MergedFile - Wide Scopeapdio.pt/.../IO2018-Livro_de_Resumos-completo.pdf · • Silvério Simões Rosa, Instituto de Telecomunicações e Universidade da Beira Interior • Susana

IO 2018XIX Congresso da APDIO

Livro de Resumos

Universidade de Aveiro

5, 6 e 7 de Setembro de 2018

ii

Conteúdo

Mensagem de Boas-Vindas 1

Mensagem do Presidente eleito do EURO 3

Comissão Organizadora 5

Comissão de Programa 7

Programa 10

Resumos 11Sessão Plenária 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12Sessão W1: EstudIO - SISCOG * . . . . . . . . . . . . . . . . . . . . 13

Resumos alargados da sessão EstudIO . . . . . . . . . . . . . . 14Sessão W2: Continuous Optimization: joint session APDIO-SEIO . . 25Sessão W3: Supply Chain and Production Management I * . . . . . 27Sessão W4: Logistics Allocation Problems . . . . . . . . . . . . . . . 29Sessão W5: Multicriteria Decision Making * . . . . . . . . . . . . . . 31Sessão W6: Risk Management and Uncertainty Modelling * . . . . . 34Sessão TA1: DEA and Performance Analysis I * . . . . . . . . . . . 39Sessão TA2: Economics, Finance and Game Theory . . . . . . . . . 41Sessão TA3: Fleet Management and Transportation * . . . . . . . . 42Sessão TA4: Logistics in HealthCare * . . . . . . . . . . . . . . . . . 45Sessão TA5: Metaheuristics for Scheduling Problems * . . . . . . . . 47Sessão TA6: Data Mining and Data Analysis * . . . . . . . . . . . . 49Sessão TB1: Inventory Management . . . . . . . . . . . . . . . . . . 52Sessão TB2: Discrete Optimization and Graphs - Applications * . . 55Sessão TB3: Scheduling in Industry * . . . . . . . . . . . . . . . . . 57Sessão TB4: OR in Health and Life Sciences . . . . . . . . . . . . . 60Sessão TB5: Multiobjective Optimization I * . . . . . . . . . . . . . 63Sessão Plenária 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

iii

iv Conteúdo

Sessão TC1: Decision Support Systems * . . . . . . . . . . . . . . . 67Sessão TC2: Simulation and Optimization * . . . . . . . . . . . . . . 69Sessão TC3: Supply Chain and Production Management II . . . . . 71Sessão TC4: Logistics and Transportation . . . . . . . . . . . . . . . 73Sessão TC5: Multicriteria Decision Making - Methodology * . . . . . 76Sessão TC6: Technology Management and Policy . . . . . . . . . . . 78Sessão F1: DEA and Performance Analysis II . . . . . . . . . . . . . 82Sessão F2: Discrete Optimization and Graphs - Methodology * . . . 84Sessão F3: Vehicle Routing * . . . . . . . . . . . . . . . . . . . . . . 86Sessão F4: Location and Distribution * . . . . . . . . . . . . . . . . 88Sessão F5: Energy * . . . . . . . . . . . . . . . . . . . . . . . . . . . 90Sessão F6: Multiobjective Optimization II . . . . . . . . . . . . . . . 93Sessão Plenária 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Lista de Moderadores 97

Lista de Autores da Sessão EstudIO 99

Lista de Autores 101

Mensagem de Boas-Vindas

Caros Congressistas

Em nome da Comissão Organizadora, é com muito gosto que vos damos asboas-vindas ao IO 2018 !

No ano em que a Associação Portuguesa de Investigação Operacional –APDIO celebra o seu 40o aniversário, assumimos o desafio de organizar, naUniversidade de Aveiro, o seu XIX Congresso, com o lema “IO – Criar valorpara a sociedade”. Trata-se, simultaneamente, de um desafio e de uma honra,pelo que tem significado a APDIO, ao longo destes 40 anos, para professores,estudantes, investigadores e membros de organizações de diferentes naturezas.De facto, nos nossos Congressos, temos vindo a refletir em conjunto de umaforma aberta e construtiva sobre os mais variados temas, através da partilhados nossos conhecimentos, quer sejam mais teóricos, quer sejam mais apli-cados, mas sempre no sentido de nos enriquecermos como indivíduos, comoassociação e, desta forma, contribuirmos para uma sociedade melhor. O lemadeste ano – IO – Criar valor para a sociedade – pretende evidenciar, precisa-mente, a necessidade de nos afirmarmos, cada vez mais, através da colocaçãodo nosso conhecimento ao serviço das organizações, sejam elas empresas in-dustriais ou de serviços, instituições sem fins lucrativos, instituições ligadasao poder central ou autárquico, ou outras.

Neste Congresso serão apresentadas 119 comunicações organizadas emsessões paralelas, 5 trabalhos na sessão dedicada ao EstudIO e 3 comunicaçõesem sessões plenárias, proferidas por especialistas de mérito reconhecido inter-nacionalmente. Temos ainda a honra de receber o Presidente eleito do EURO(The Association of European Operational Research Societies), o ProfessorImmanuel Bomze que fará a sua intervenção na sessão de abertura do Con-gresso. A quantidade, qualidade e variedade destas comunicações permite-nosafirmar que este Congresso tem todas as condições para ser bem-sucedido!Gostaríamos, assim, de expressar os nossos sinceros agradecimentos: a todosos autores dos artigos e das comunicações, por contribuírem para a qualidadecientífica do nosso Congresso; a todos os congressistas, que dão vida a este

1

2 Mensagem de Boas-Vindas

evento, e que terão a responsabilidade de levar a mensagem do Congressopara os seus ambientes profissionais, mas também pessoais; aos oradores dassessões plenárias, Professor Alexandre Dolgui, Professor Bernardo Almada-Lobo e Engenheiro António Murta, que aceitaram participar neste Congresso,disponibilizando o seu tempo, e partilhando connosco o seu conhecimento e asua experiência. Finalmente, um agradecimento muito especial à Direção daAPDIO, pela confiança que depositou em nós e pela ajuda sempre pronta eamiga.

Terminamos desejando que o IO 2018 vá ao encontro das expectativas detodos, na certeza de que tudo faremos para que se sintam bem durante oCongresso, na Universidade e na cidade de Aveiro!

Mensagem do Presidenteeleito do EURO

It is always a pleasure to congratulate an active scientific society on occasionof the 40th anniversary of its foundation; however, it is a bit arbitrary asBabylonians would have started to celebrate already four years ago...

More important to me is to witness the success of a thriving association,i.e., its members. No doubt that the important Portuguese personalities inOperational Research were always well connected and enjoyed an excellentreputation in the international community; nevertheless, the newly emerginggeneration of Portuguese Operational Researchers continues on this path withimpressive visibility and recognition of their scientific achievements, alongwith a rapidly growing network on a global level. An important testimony ofthis fact is the sheer number of well-received international scientific meetingsthat are co-organized by APDIO and/or its active members every year. Allthis is another fundamental and well-founded reason to celebrate!

In this vein, I wish APDIO and its members, including the generations ofresearchers to come, the same success in scientific progress. May IO 2018, theyearly congress commencing now contribute to this goal by a fruitful exchangeand development of fresh ideas for the benefit of all delegates and our field ofOperational Research!

Immanuel Bomze

3

4

Comissão Organizadora

Presidentes

• Ana Raquel Xambre, Universidade de Aveiro, Departamento deEconomia, Gestão, Engenharia Industrial e Turismo([email protected])

• Helena Alvelos, Universidade de Aveiro, Departamento de Economia,Gestão, Engenharia Industrial e Turismo([email protected])

Membros

• Agostinho Agra, Universidade de Aveiro, Departamento de Matemática([email protected])

• Ana Moura, Universidade de Aveiro, Departamento de Economia,Gestão, Engenharia Industrial e Turismo([email protected])

• Andreia Hall, Universidade de Aveiro, Departamento de Matemática([email protected])

• Carina Pimentel, Universidade de Aveiro, Departamento de Economia,Gestão, Engenharia Industrial e Turismo([email protected])

• Cristina Requejo, Universidade de Aveiro, Departamento de Matemática([email protected])

• Rui Borges Lopes, Universidade de Aveiro, Departamento de Economia,Gestão, Engenharia Industrial e Turismo([email protected])

• Tatiana Tchemisova, Universidade de Aveiro, Departamento deMatemática([email protected])

5

6

Comissão de Programa

Presidente• Maria João Alves, Universidade de Coimbra, Faculdade de Economia

Membros• Agostinho Agra, Universidade de Aveiro, Departamento de Matemática• Alberto Adrego Pinto, Universidade do Porto, Departamento de Matemática• Ana Isabel Pereira, Instituto Politécnico de Bragança, Escola Superior de Tecnologia

e Gestão• Ana Luísa Custódio, Universidade Nova de Lisboa, Faculdade de Ciências e

Tecnologia• Ana Paula Barbosa Póvoa, Universidade de Lisboa, Instituto Superior Técnico• Ana Paula Teixeira, Universidade de Trás-os-Montes e Alto Douro• Ana Raquel Xambre, Universidade de Aveiro, Departamento de Economia, Gestão,

Engenharia Industrial e Turismo• Ana Viana, Instituto Politécnico do Porto, Instituto Superior de Engenharia• António José Rodrigues, Universidade de Lisboa, Faculdade de Ciências• Armando Brito Mendes, Universidade dos Açores, Faculdade de Ciências e

Tecnologias• Bernardo Almada-Lobo, INESC TEC e Universidade do Porto, Faculdade de

Engenharia• Cândida Mourão, Universidade de Lisboa, CMAF-CIO e Instituto Superior de

Economia e Gestão• Carlos Ferreira, Universidade de Aveiro, Departamento de Economia, Gestão,

Engenharia Industrial e Turismo• Carlos Henggeler Antunes, Universidade de Coimbra, Departamento de Engenharia

Electrotécnica e de Computadores• Cesaltina Pires, Universidade de Évora, Departamento de Gestão• Clara Bento Vaz, Instituto Politécnico de Bragança, Escola Superior de Tecnologia

e Gestão• Cláudio Alves, Universidade do Minho, Escola de Engenharia• Dalila Fontes, Universidade do Porto, Faculdade de Economia• Domingos Moreira Cardoso, Universidade de Aveiro, Departamento de Matemática

7

8 Comissão de Programa

• Filipe Alvelos, Universidade do Minho, Escola de Engenharia• Helena Alvelos, Universidade de Aveiro, Departamento de Economia, Gestão,

Engenharia Industrial e Turismo• Isabel Cristina Lopes, Instituto Politécnico do Porto, Instituto Superior de

Contabilidade e Administração do Porto• Isabel Gomes, Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia• Ismael Vaz, Universidade do Minho, Escola de Engenharia• Joana Dias, Universidade de Coimbra, Faculdade de Economia• João Claro, Universidade do Porto, Faculdade de Engenharia• João Miranda, CERENA e Instituto Politécnico de Portalegre, Escola Superior de

Tecnologia e Gestão• João Paulo Almeida, Instituto Politécnico de Bragança• João Paulo Costa, Universidade de Coimbra, Faculdade de Economia• Jorge Orestes Cerdeira, Universidade Nova de Lisboa, Departamento de Matemática• Jorge Pinho de Sousa, Universidade do Porto, Faculdade de Engenharia• José Fernando Gonçalves, Universidade do Porto, Faculdade de Economia• José Fernando Oliveira, Universidade do Porto, Faculdade de Engenharia• José Manuel Valério de Carvalho, Universidade do Minho, Escola de Engenharia• José Soeiro Ferreira, Universidade do Porto, Faculdade de Engenharia• Lia Oliveira, Instituto Politécnico de Viana do Castelo, Escola Superior de Ciências

Empresariais• Luís Miguel Dias, Universidade de Coimbra, Faculdade de Economia• Manuel Matos, Universidade do Porto, Faculdade de Engenharia• Margarida Vaz Pato, Universidade de Lisboa, Instituto Superior de Economia e

Gestão• Maria Antónia Carravilla, Universidade do Porto, Faculdade de Engenharia• Maria Eugénia Captivo, Universidade de Lisboa, Faculdade de Ciências• Marília Pires, Universidade do Algarve, Faculdade de Ciências e Tecnologia• Mónica Oliveira, Universidade de Lisboa, Instituto Superior Técnico• Pedro Amorim, Universidade do Porto, Faculdade de Engenharia• Pedro Oliveira, Universidade do Porto, ICBAS• Silvério Simões Rosa, Instituto de Telecomunicações e Universidade da Beira Interior• Susana Relvas, Universidade de Lisboa, Instituto Superior Técnico• Tatiana Tchemisova Cordeiro, Universidade de Aveiro, Departamento de Matemática

Programa 9

Program

a

TA1 (sa

la 23.3

.4): DE

A and

Perform

ance A

nalysis I

*F1 (

sala 23.

3.4): D

EA and

Perform

ance A

nalysis I

ITA2

(sala 2

3.3.5):

Econom

ics, Fin

ance an

d Gam

e Theor

y F2 (

sala 23.

3.5): D

iscrete

Optim

ization

and Gra

phs - M

ethodo

logy *

TA3 (sa

la 23.3

.9): Fle

et Mana

gement

and Tra

nsporta

tion *

F3 (sala

23.3.9

): Vehi

cle Rou

ting *

TA4 (sa

la 23.3

.10): Lo

gistics

in Healt

hcare *

F4 (

sala 23.

3.10):

Locatio

n and D

istribu

tion *

TA5 (sa

la 23.3

.14): M

etaheu

ristics f

or Sche

duling

Proble

ms *

F5 (sala

23.3.1

4): Ene

rgy *

TA6 (sa

la 23.3

.15): D

ata Mi

ning an

d Data

Analys

is *F6 (

sala 23.

3.15):

Multio

bjectiv

e Optim

ization

II11:

00 - 11:

30Cof

fee bre

ak11:

00 - 11:

30Cof

fee bre

akTB1

(sala 2

3.3.4):

Invent

ory Ma

nagem

entTB2

(sala 2

3.3.5):

Discre

te Optim

ization

and Gra

phs - A

pplicat

ions *

TB3 (sa

la 23.3

.9): Sch

eduling

in Indu

stry *

TB4 (sa

la 23.3

.10): O

R in He

alth and

Life Sci

ences

TB5 (sa

la 23.3

.14): M

ultiobj

ective O

ptimizat

ion I *

13:30 -

14:30

Registo

14:30 -

15:00

Sessão

de Abe

rtura (s

ala 23.

1.6): co

m a par

ticipaçã

o de Lu

ís Filipe

Castro

(Vice-R

eitor da

UA)

e Imma

nuel Bo

mze (Pr

esident

e Eleito

do EU

RO)15:

00 - 16:

00Ses

são Ple

nária 1

(sala 2

3.1.6):

Alexan

dre Do

lgui

15:00 -

16:00

Sessão

Plenár

ia 2 (sa

la 23.1

.6): Be

rnardo

Almada

-Lobo

16:00 -

16:30

Coffee

break

TC1 (sa

la 23.3

.4): De

cision

Suppor

t System

s *W1

(sala 2

3.3.4):

EstudI

O - SISC

OG *

TC2 (sa

la 23.3

.5): Sim

ulation

and Op

timizat

ion *

W2 (sa

la 23.3

.5): Co

ntinuou

s Optim

ization

: joint S

ession

APDIO

-SEIO

TC3 (sa

la 23.3

.9): Sup

ply Cha

in and

Produc

tion Ma

nagem

ent II

W3 (sa

la 23.3

.9): Sup

ply Cha

in and

Produc

tion Ma

nagem

ent I *

TC4 (sa

la 23.3

.10): Lo

gistics

and Tra

nsporta

tionW4

(sala 2

3.3.10

): Logist

ics and

Alloca

tion Pro

blems

TC5 (sa

la 23.3

.14): M

ulticrit

eria De

cision

Making

- Meth

odology

*W5

(sala 2

3.3.14

): Multi

criteria

Decisi

on Ma

king - A

pplicat

ions *

TC6 (sa

la 23.3

.15): T

echnol

ogy Ma

nagem

ent and

Policy

W6 (sa

la 23.3

.15): R

isk Ma

nagem

ent and

Uncer

tainty M

odeling

*17:

30 - 17:

45Cof

fee bre

ak----

----17:

45 - 18:

45Ass

emble

ia Gera

l da AP

DIO (sa

la 23.1

.6)19:

00 - …

Cockta

il de B

oas-Vin

das----

----19:

30 - …

Passeio

de Mo

liceiro

e Janta

r do Co

ngress

o

5 de Se

tembro

(quarta

-feira)

6 de Se

tembro

(quinta

-feira)

7 de Se

tembro

(sexta

-feira)

9:30 - 1

1:00

9:30 - 1

1:00

16:00 -

17:30

16:30 -

18:20

11:30 -

13:20

11:30 -

12:30

Sessão

Plenár

ia 3 (sa

la 23.1

.6): An

tónio M

urta

12:30 -

13:20

Entreg

a de Pré

mios e

Sessão

de Enc

errame

nto (sa

la 23.1

.6)

13:30 -

14:45

Almoço

13:30 -

14:45

Almoço

*Sessãoexclusivamente

emPortugu

ês/this

sessionwilluse

exclusively

thePortugu

eselangu

age

10

Programa de 5 de Setembro 11

5 de Setembro (quarta-feira)

13:30 - 14:30 Registo

14:30 - 15:00 Sessão de Abertura (sala 23.1.6): com a participação deLuís Filipe Castro (Vice-Reitor da UA) eImmanuel Bomze (Presidente Eleito do EURO)

15:00 - 16:00 Sessão Plenária 1 (sala 23.1.6): Alexandre Dolgui

16:00 - 16:30 Coffee break

16:30 - 18:20

W1 (sala 23.3.4): EstudIO - SISCOG *W2 (sala 23.3.5): Continuous Optimization: joint Session APDIO-SEIOW3 (sala 23.3.9): Supply Chain and Production Management I *W4 (sala 23.3.10): Logistics and Allocation ProblemsW5 (sala 23.3.14): Multicriteria Decision Making - Applications *W6 (sala 23.3.15): Risk Management and Uncertainty Modeling *

19:00 - . . . Cocktail de Boas-Vindas

* Sessões exclusivamente em Português

12 Sessão Plenária 1

Sessão Plenária 15 de Setembro, Quarta-feira, 15:00 - 16:00Sala: 23.1.6

Moderador: José Fernando Oliveira

Combinatorial design of paced production lines in machiningenvironment

Alexandre Dolgui IMT Atlantique, Nantes, França

Resumo. A complex machine or machining line consists of a sequenceof work positions through which products move one way in order to be pro-cessed. Designing such a production system represents a long-term decisionproblem involving different crucial decision stages. Combinatorial design isone of them; it mostly deals with assigning the set of indivisible units of work(named tasks or operations) to work positions (or stations). In literature, themost attention was paid for combinatorial design of assembly lines (assemblyline balancing problems). In our work, we develop approaches and formula-tions of combinatorial design for machining lines and complex machines.

In this talk, a brief survey of our results on combinatorial design of com-plex machines and machining lines is presented. This deals not only withassigning tasks to a sequence of linearly ordered workstations, but necessitatealso to solve jointly some other decision problems, such as process planning,equipment selection, configuration design or task sequencing. Making simul-taneously different decisions can reach better final line performance and effec-tiveness. Advanced operational research techniques are used, a decision aidsoftware is developed and applied in the automotive industry.

Sessão W1: EstudIO - SISCOG * 13

Sessão W1: EstudIO - SISCOG *5 de Setembro, Quarta-feira, 16:30 - 18:20Sala: 23.3.4

Organização: Joana DiasModeradora: Joana Dias

Sistema de apoio à decisão para decisões online de atribuição de preçose gestão de frota em empresas de aluguer de automóveis

José Pedro Silva, Beatriz Brito Oliveira, José Fernando Oliveira

Reallocating Operating Room Time Among Surgical Services

Luísa Lubomirska, Inês Marques,

Analysis Of Surgical Processes In The Central Operating Theatre –Centro Hospitalar Lisboa Norte

Mariana J. Patrão, Inês Marques, Ana Barbosa-Póvoa

Design and Planning of Agri-Food Supply Chains

Lourenço Cruz, Ana Barbosa-Póvoa

Blood Supply Chain Planning: The Portuguese Case

Ana Margarida Araújo, Inês Marques, Ana Barbosa-Póvoa

Ver resumos alargados nas páginas seguintes.

14 Resumos alargados da Sessão EstudIO - SISCOG

Sistema de apoio à decisão para decisões online deatribuição de preços e gestão de frota em empresas de

aluguer de automóveis

José Pedro Silva∗, Beatriz Brito Oliveira, José Fernando Oliveira

∗Faculdade de Engenharia da Universidade do Porto

Descrição do problemaA necessidade de aumentar a competitividade e produtividade face aos recursos

existentes, tem-se tornado um dos principais focos das empresas, sendo que a in-dústria de aluguer de automóveis não é exceção. Para tornar estas empresas cadavez mais competitivas, todas as decisões relevantes devem ser ponderadas, con-siderando toda a informação disponível, de forma estruturada e preferencialmenteapoiadas por sistema de apoio à decisão. O problema aqui considerado prende-secom as decisões-chave de nível tático/operacional que uma empresa de aluguer deautomóveis deve tomar, nomeadamente a atribuição de preços e a consequente ges-tão da frota e da procura. Assim, é necessário um sistema que consiga apoiar asdecisões da empresa de forma a conseguir atingir o seu objetivo, neste caso o lucro.O objetivo principal é definir o preço de cada tipo de aluguer, que depende de váriascaracterísticas, tal como as estações de check-in e check-out, os tempos inicial e finalda reserva e ainda o grupo/tipo de carro envolvido. Pretende-se, assim, definir opreço individual de cada tipo de aluguer de forma a maximizar o lucro, tendo emconta os recursos existentes e a procura para cada nível de preço. Isto é, assume-seque para preços mais baixos a procura tende a ser maior e vice-versa. Para alémdo preço, pretende-se também apoiar decisões-chave de gestão da frota, ajustando ostock em cada estação ao longo do tempo de forma a conseguir atingir os objetivoscom os recursos existentes. Recorre-se ainda a realocações de veículos “em vazio”de forma a conseguir responder melhor à procura. Outro recurso disponível paraatingir o mesmo objetivo passa por oferecer upgrades aos clientes a que não sejapossível responder com o grupo pretendido. Em suma, o sistema desenvolvido deveapoiar a empresa nestas decisões críticas e torná-la mais competitiva e capaz deatingir os objetivos pretendidos.

Relevância do problemaA indústria de aluguer de automóveis está cada vez mais competitiva e demon-

stra um crescimento acentuado nos últimos anos. Assim, cada vez se torna maisrelevante a otimização das mais relevantes decisões táticas e operacionais tomadaspela empresa. A definição do preço é crucial para o sucesso da empresa, visto queum preço demasiado alto pode levar à perda de clientes para a concorrência e, assim,à falta de vendas e à consequente acumulação de veículos parados sem utilização.Por outro lado, um preço demasiado baixo pode levar a baixos retornos mesmo comtodos os ativos em utilização e à subvalorização dos mesmos. No que respeita àgestão de frota neste âmbito, esta envolve várias decisões cruciais quanto ao corretodesenrolar do exercício e à gestão da procura. A decisão de alocação e realocação

Resumos alargados da Sessão EstudIO - SISCOG 15

de recursos, ou seja, do stock disponível em cada estação, a decisão de oferecer up-grades, entre outras, são decisões que podem ditar o sucesso ou insucesso da empresa.Uma das principais dificuldades neste ramo prende-se com a incerteza na procura,em especial para períodos mais distantes. Esta encontra-se diretamente relacionadacom a competitividade desta indústria já que depende dos preços da concorrência edo mercado em geral. Torna-se imperativo, portanto, que as decisões sejam tomadasnuma frequência curta e de forma online para assim conseguir otimizar as decisões acada momento, com a informação mais atualizada possível. Num mercado cada vezmais competitivo cada pequena vantagem pode ser crucial e pode ditar o futuro daempresa. Assim, com este sistema, pretende-se ajudar a empresa a tornar-se maiscompetitiva no mercado.

Metodologia utilizada na resoluçãoPara conseguir o objetivo proposto, começou-se por desenvolver um modelo de

programação matemática MIP que define todas as variáveis de decisão e parâmetrosnecessários para atingir o objetivo. O objetivo é maximizar o lucro da empresa,sendo que este corresponde à receita obtida das reservas efetuadas menos os custos detransferências vazias e upgrades efetuados. Este modelo tem restrições importantes,como as de controlo do stock, nas quais o stock numa estação específica no períodode tempo atual é igual ao do período anterior acrescido das reservas e transferênciasvazias que chegam menos as que saíram no período anterior. Outras restriçõescruciais são as da procura, nas quais o número de reservas efetuadas é limitado pelaprocura associada ao nível de preço escolhido, para cada tipo de aluguer. O modeloinclui ainda restrições que apenas permitem upgrades entre classes de veículos quetenham sido definidas pela empresa como possíveis. A metodologia de resoluçãocompreende a implementação do modelo MIP e a sua resolução recorrendo ao solverCPLEX. O modelo foi validado, recorrendo a instâncias dummy para exemplificaçãodas suas funcionalidades e, seguidamente, a instâncias baseadas na literatura e detamanho realista. A resolução do modelo será implementada em horizonte rolante,de forma a garantir a atualização online das decisões ótimas de preço e gestão defrota. Este é um problema em que as decisões futuras têm um impacto significativonas decisões relativas ao período de tempo atual. Por exemplo, a atribuição de umpreço muito reduzido a um aluguer que se inicie no período de tempo seguinte numacerta estação, vai aumentar a procura nessa estação, fazendo com que seja necessáriogarantir, no momento atual de decisão, que o stock necessário seja enviado para essaestação. A resolução em horizonte rolante permite que estas ligações entre decisõesde diferentes períodos temporais sejam consideradas, garantindo ao mesmo tempo ofoco na decisão atual (dado que as futuras podem ser otimizadas depois, com acessoa dados atualizados). O modelo está preparado para incluir de forma modular arelação procura-preço e assim permite explorar em mais detalhe a relação com aconcorrência e com o mercado em geral. Assim pode utilizar-se um pressupostomais simples de forma a validar o modelo e mais tarde aprofundar esta relação eintroduzir valores mais realistas com todas incidências no modelo. Neste caso, deacordo com a literatura, assumiu-se que a procura é sensível ao preço e assim varia-se o valor da procura conforme o preço escolhido (quanto maior o preço, menor aprocura). Isto deve-se em grande parte à competitividade do mercado no qual adiferenciação entre concorrentes não é considerada significativa.


Reallocating Operating Room Time Among SurgicalServices

Luísa Lubomirska∗, Inês Marques,

∗Centre for Management Studies, Instituto Superior Técnico, Universidade deLisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, Portugal

[email protected]

Problem descriptionThe surgical suite (SS) is the largest cost and revenue center within a hos-

pital, while having large impact in many other services in the hospital. Costsare not only related with the expensive and very specialized equipment thateach surgical procedure requires, but also with the highly skilled staff. SS isalso a large source of revenues, due to the active role in hospital admissions.Therefore, the SS is a major challenge in the hospital and is crucial for thefinancial health and smooth functioning of the hospital. The SS has been stud-ied by many researchers. The literature addresses different levels of decisionswhen concerning SS planning and scheduling: strategic (long-term), tactical(medium-term) and operational (short-term). This work focuses on the tacti-cal level of decision which plans staff, patients and resources, both in the SSand in up and downstream facilities. In the literature, this includes designingthe so-called Master Surgical Schedule (MSS) which is a cyclic timetable thatassigns timeslots, rooms and days to each surgical specialty or surgical group.This work is developed in collaboration with a Portuguese public hospital andaims to improve efficiency of the SS. Given the hospital restrictions in termsof space and human resources (settled in the strategic level), this work reallo-cates the operating room time among the surgical services, proposing a newMSS. This Portuguese hospital has a long waiting list for surgery. This can bedue to the inflexible MSS which has been used for about 30 years. The newMSS intends to adapt supply to surgical demand, distributing the timeslotsaccording to the waiting list of each specialty. This distribution has not onlyto comply with physical restrictions of the SS, but also with the number ofsurgeons, anesthesiologists and nurses available per timeslot, and capacity inup and downstream services. Furthermore, this new MSS aims to improveefficiency in the SS and to increase throughput. These objectives can onlybe achieved if the new MSS is aligned with stakeholders’ interests and per-spectives which is difficult to reach after a long period working with the sameschedule. To be able to implement a new MSS in the hospital, stakeholders


must be engaged. Thus, another objective is to maximize stakeholders’ sat-isfaction by means of surgeons and anesthesiologists preferences in terms ofspecific timeslots, days and rooms, and of practical insights on the number ofhours daily assigned to each specialty.

Problem relevanceThe operations research literature on SS capacity planning has increased

in the last few years. Though most of this literature is dedicated to the op-erational level of decisions, leaving the strategic and tactical level with lessattention from researchers. The Portuguese Health National Service has fixeda maximum response time (in number of days) that a patient can wait fora surgery which depends on the priority level of the patient (e.g. a patientwith non-oncologic disease, priority level 3, should wait no more than 60 daysfor a surgery). Nonetheless, the waiting list of the hospital under study ex-ceeds these values which turns to high financial penalties for the hospital. Asan example, 249 patients are currently waiting for a plastic surgery and theaverage waiting time is 223 days. The long waiting list for surgery has evengreater impact due to the importance of the hospital to the region. Servingaround 325 thousand people, this is the reference hospital for specialties suchas plastic surgery, vascular surgery, pediatric surgery and bariatric surgery.By suggesting a new MSS this study aims at reducing the waiting list forsurgery considering the available resources, and to turn the waiting list closerto the targets established by the govern avoiding the high financial penal-izations. The model is also relevant for the manager of the SS, supportingthe decision-making process by obtaining more credible, independent and un-biased solutions through a systematic approach with potential to be betteraccepted by the remaining SS stakeholders. It is expected that the implemen-tation of the model’s solutions will contribute to a better organization of SS.The model should simplify the design of new MSSs and increase the dynamicof adjusting the MSS to changes in the surgical demand profile. Differentfrom other optimization problems published in the field of SS planning, thisproblem considers stakeholders’ preferences and insights on the SS planning.

Methodology used to solve the problemThe problem is formulated as a mixed integer programming model which

is solved using Cplex software. Preliminary results solve the model to opti-mality in 45 seconds. The proposed MSS will be compared with the MSScurrently implemented in the hospital and evaluated on major key perfor-mance indicators. The differences will be analyzed and discussed with themain SS stakeholders in the hospital.


Analysis Of Surgical Processes In The CentralOperating Theatre – Centro Hospitalar Lisboa NorteE

Mariana J. Patrão∗, Inês Marques, Ana Barbosa-Póvoa∗Centre for Management Studies, Instituto Superior Técnico, Universidade de

Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa, [email protected]

Problem descriptionIn this work the Central Operating Theatre (COT) of Centro Hospitalar Lisboa

Norte is the case understudy. COT’s perioperative process (Figure 1) is composedby 3 sub-processes – preoperative, intraoperative and postoperative. These sub-processes include medical (e.g. surgery) and non-medical (e.g. prepare the operatingroom for surgery) activities that require diverse physical and human resources, whichhave key roles on the process efficiency. Therewith, COT’s large patient waitinglist and costs are a major concern to the organization’s management and remainingstakeholders (e.g. patients, medical teams and hospital administrators), which leadsto the need of efficiency improvement in the perioperative process. The challenge of

Pre

op

era

tive From the registration in

the waiting list for surgeryto the admission of thepatient in the hospital.

Intr

ao

pe

rati

ve From the patient's

hospital admission to theend of surgery.

Po

sto

pe

rati

ve From the end of surgery

to patient discharge.

Figure 1: Perioperative Process.

this work is then to evaluate the efficiency of the current process and consequentlypropose solutions to overcome the possible identified inefficiencies and improve theprocess efficiency of the COT’s system.

MotivationIn Portugal, the National Health Service (Sistema Nacional de Saúde, SNS)

aims to ensure the population’s right to high quality healthcare treatment. Itsmain objective is to protect the individual and collective health and to do so, it iscomposed by integrated health care – promotion and vigilance of health, patient’sdisease prevention, diagnosis and treatment, and medical and social rehabilitation.The National Healthcare Plan (Plano Nacional de Saúde) is a basic element ofhealthcare politics in the country, which determines the strategic path of interventionin the SNS. The National Healthcare Plan aims to maximize the gains in population’shealth by aligning and integrating sustainable efforts in all society’s sectors and thefocus is on access, quality, sustainable policies and citizenry. Considering this, themost recent National Healthcare Plan (until 2020) builds upon the previous onesand aims to maximize the results and to be aligned with the principles and strategicorientations of the World Health Organization. With this, the proposals are toreduce premature mortality (before 70 years), improve the healthy life expectancy


1. Understanding

• identify theproblem to solve;

• engage theentities involved inthe project.

2. Procedure

• map the currentprocesses;

•define measuresto achieve theobjectives;

• evaluate thecurrent status;

• identify thebottlenecks andflaw points of theprocess;

• identify the non-valuableactivities;

• identify theativities thatrequireimprovements.

3. Re-engineering

• propose a set ofprocess maps thatimprove theefficiency;

• remove non-valuableactivities;

• improve theremainingactivities of theprocess.

4. Evaluation

• apply simulationto re-engineeredprocesses;

• evaluate theobtained results.

5. Implementation

• implement the re-engineeredprocesses into thereal-life case;

•analyseprocessesimplementation'sresults.

Figure 2: Steps of the proposed methodology.

(at 65 years) and reduce risk factors associated with non-transmissible diseases (e.g.obesity). To achieve this, it is necessary to improve system’s performance as wellas its integrated capacity. In this context, hospitals are critical organizations inthe health system and the organization of the associated processes is essential toguarantee a sustainable performance, being this not only a high financial capacity,but also an efficient use of available resources while meeting the patient’s needs.Towards this, critical services within the hospital should be highly organized as isthe case of Operating Theatres (OTs). The surgical interventions performed, in theOTs, are the major source of admissions into a hospital. This and the large andsteadily increasing surgical demand, leads to a service with large expenses but also asource of revenues, while having a very important role in the health being of patientsand in the performance of many other units of the hospital. For instance, recoveryrooms are downstream services and provide a monitored rehabilitation of the patientafter surgery. Therefore, OTs and the respective recovery rooms are critical assetsto hospitals. Thereby, COT’s efficiency is a major concern to the stakeholders ofHospital Santa Maria.

MethodologyTo achieve the improvement of COT’s performance, the methodology in Figure

2 has been followed. This methodology includes 5 main steps, which are composedby several sub steps. The first step aims at understanding the current functioningof COT. Towards this, the identification of the problem is performed exploringthe stakeholders’ engagement – through their involvement into the project withinterviews. Step 2 involves the mapping of the activities of the current processes atCOT. Mapping contributes to the identification and definition of the measures to usewhen targeting the defined objectives. These measures allow to identify bottlenecksand flaw points through the process. The identification of the non-valuable activitiesand the activities that require amendments is performed. With the identificationcompleted, step 3 is initiated by proposing a set of process maps that allow thegain of efficiency in the process. This may require the removal of non-valuableactivities and the improvement of the remaining ones. To test the results, the 4th


step validates the developed re-engineered processes with simulation. The processwith best results in the simulation is suggested as the one to be implemented intothe real system and results are then evaluated (step 5).

ResultsThe results provided by the methodology’s application are COT’s perioperative

map – macro and micro processes - as well as the description of activities and re-quired resources (e.g. surgeons and surgical kits). In addition, the measures toprocess evaluation are defined having into consideration different classes – quality(e.g. rate of performed surgeries within the guaranteed response time), complexity(e.g. monthly case volume), occupation (e.g. Operating Room occupancy level),cancellations (e.g. rate of cancelled surgeries), time (e.g. idle time) and satisfac-tion (e.g. patient-reported outcomes). As a final outcome, a new process to beimplemented in COT is proposed which is able to achieve efficiency gains. As thepresent work is currently ongoing, step 1 (Figure 2) has been completed and steps2 to 5 (Figure 2) are under development. As preliminary results it can be said thatsome of the COT’s studied processes have indeed a set of non-added value activitiesthat can be eliminated or changed so as to enhance the overall process efficiency.Such results will be presented and discussed, aiming to reduce patients’ waiting list(increasing throughput) and decrease of the organization’s costs, enhancing stake-holders’ satisfaction.


Design and Planning of Agri-Food Supply Chains

Lourenço Cruz∗, Ana Barbosa-Póvoa


[email protected]

Problem descriptionAgri-food supply chains (AFSCs) possess a series of characteristics that

impede typical supply chain (SC) tools and models to be used successfully,thus creating a need for specific frameworks to be developed. Due to theirvastness and complexity, designing AFSCs is difficult and time consuming, aproblem which is yet to be tackled in a satisfactory manner. Many researchersare currently contributing to solving this problem by putting forward refinedmodels which account for specific characteristics of AFSCs (perishability, un-certainty, data availability and transparency), reason for which the area hasgained significant attention from the scientific community in recent years.However, recent reviews point out to a lack of integrated solutions, arguingthat most of the models proposed so far are only considering a subset of all thecharacteristics and, as such, still fail to accurately describe AFSCs. The workhere developed hopes to further contribute to solve this problem by identify-ing existing gaps in currently proposed AFSC design models. Afterwards, anew model is developed to support supply chain managers to design and plantheir AFSCs.

Problem relevanceAgriculture and the agribusiness sector currently represents 10 percent of

worldwide consumer spending, provides 40% of global employment, and isreported to encompass EUR 117.4 and 137.9 billion in imports and exportsin the European Union, respectively. Despite its considerable economic, so-cial, and environmental impact (the sector is responsible for 30% of worldwidegreenhouse gas emissions), major concerns regarding the sector’s future abilityto provide food to a growing and more demanding Human population are onthe rise. AFSCs are vastly complex and entail a series of players which mustwork together to fulfil the ever-increasing demands of consumers. As such,these supply chains are currently the focus of extensive work. However, thegrowing number of scientific articles zeroing in on AFSC management pointsout to vast gaps in the literature. These gaps must be filled to ensure both theindustry and academia alike can adapt current frameworks and decision toolsto solve the problems of the present and the future. As mentioned, AFSCscannot be designed and managed using conventional SC tools, as these chainshave specific characteristics that set them apart. Namely, product perishabil-ity and heterogeneity, uncertainty in supply (weather conditions and natural


disasters) and demand, high lead times between order placement and productreception, among others, play an important role and must be accounted for.Such uniqueness implies tools must be created to design AFSCs specifically,avoiding the application of generic frameworks which fail to translate howAFSCs operate. Increasing efforts are being done in this front, with more andmore models being suggested to account for the characteristics of AFSCs.Nonetheless, recent reviews indicate most efforts account for one or a smallset of characteristics, instead of regarding AFSCs in their entirety. Althoughhelpful in paving the way towards future improvement, these models are yetto properly translate the behaviour of AFSCs and, as such, appropriate inte-grated models and frameworks have yet to be developed.

Methodology used to solve the problemDue to the increasing focus the scientific community is putting on AFSCs,

the number of scientific articles focusing on AFSC design is increasing rapidly.To better understand the most recent developments in the field, a systematicreview of the literature is being conducted, making use of the Web of Sci-ence Database. From this, existing gaps in the literature will be identifiedand summarised. Following the information collection, optimisation methodswill be explored to support the development of a new decision-making tool.For this, a Mixed-Integer Linear Programming (MILP) model is developed,which is implemented making use of the Generic Algebraic Modelling System(GAMS). The model is expected to assist AFSC design and management byproviding a more holistic approach compared to existing alternatives. Thiswill be made possible by incorporating a wider set of both SC and productcharacteristics than that of currently published models. The model will thenbe tested via its application to a Case Study, from which major learning pointswill be taken.

ResultsThe model developed allows for the design and planning of AFSCs where

the location of entities, their capacities, inventory levels, and supply chainflows are defined considering the specific characteristics of AFSCs. Althoughthe work is still ongoing, as preliminary results it can be stated that the SCstructure, meaning the development of centralised versus decentralised supplychains, has a great influence in the management of SC costs and producttraceability while guaranteeing its freshness, dealing in this way with thefood products’ perishability. Also, the presence of uncertainty in offer anddemand should be accounted for as this allows for a more realistic AFSCplanning while minimising cost and maximising service levels. Finally, theconsideration of post-harvest wastage as well as the presence of reverse flowsallow the combat of current SC wastage and, thus, the design of closed-loopstructures should be targeted to guarantee sustainability objectives.


Blood Supply Chain Planning: The Portuguese Case

Ana Margarida Araújo∗, Inês Marques, Ana Barbosa-Póvoa


[email protected]

Problem Description

The blood supply chain comprises the evolution and tracking of bloodand blood components from donor to recipient. These blood products aretransfused to patients in the context of surgical procedures, routine medicalpractices and in emergency situations. In this way, the blood supply chainencompasses several day-to-day activities, making it possible to provide thefinal blood products required for such tasks. These include the processes ofcollecting, testing and processing blood and blood products prior to their dis-tribution. Hence, the aim of this work is to characterize the Portuguese bloodsupply chain and to improve the main identified sources of inefficiencies byproposing an optimization model to handle tactical and operational decisions.

Problem Relevance

Blood and its derived components cannot be considered as conventionalproducts. In fact, they are remarkable in the sense that the consequences ofmishandling them may lead to catastrophic consequences, implicating humanlives. A shortage in blood supply is likely going to hinder scheduled/plannedprocedures or, more seriously, resulting in a patient’s untimely death, there-fore potentially having a negative impact in mortality rate. On the other hand,surplus may very well be proceeded by outdates which have significant reper-cussions society-wise, as it is ethically wrong to waste such a valuable andscarce/limited commodity with increasingly lower donation numbers (21,74donors per 1000 inhabitants in 2016 in Portugal – the lowest number in thelast nine years). Furthermore, we need to consider that the need for suchproducts will never cease to exist, which is why this is such a worthy topic tobe studied and its importance acknowledged. The management of the bloodsupply chain is particularly challenging due to a variety of reasons, rangingfrom the perishability of the products, which is not only short, but also differ-ent between them; to the challenge of matching supply and demand, being thesupply of donor blood irregular while the demand for blood products highlystochastic. Moreover, an efficient blood supply chain planning should not


only meet demand but at the same time reduce wastage and minimize costs.Literature on the topic exists, some focusing on each echelon of the supplychain and few in integrated views of the whole network. Notwithstanding, lit-erature focusing on the Portuguese blood supply chain is non-existing. Withthis work, we intend to shed some light on the Portuguese case and mitigatefragilities of the system, closing this gap.

MethodologyWith this work we aim to characterize the Portuguese blood supply chain

as well as to focus on the improvement of the main identified sources of ineffi-ciencies recurring to an optimization model to handle tactical and operationaldecisions. Specifically, we focus on the optimization of the blood supply chainplanning using a linear integer programming model applied to the case of Cen-tro de Sangue e Transplantação de Lisboa (CSTL). Some of the assumptionsthat are considered in this model are the location of demand points, which arefixed and known, as well as the locations of the processing centers and fixedcollection points. It is also assumed that a single product is collected priorto processing (whole blood) and thereafter multiple products are transportedwithin the supply chain. Additionally, ABO Rh compatibility of the bloodproducts is taken into consideration when necessary. The model is testedwith data gathered from this center which belongs to Instituto Português doSangue e da Transplantação (IPST). It aims to optimize the Portuguese bloodsupply chain management, in order to deliver the exact quantity of the rightblood product to the hospitals when and where it is required, at minimumcost. So far, the blood supply chain has been characterized and some ineffi-ciencies acknowledged. Data gathered from CSTL is currently being analyzedin order to further study the aforementioned inefficiencies. Subsequently, theformulation of the model will be followed by its application to a real casestudy.

Sessão W2: Continuous Optimization: joint session APDIO-SEIO 25

Sessão W2: Continuous Optimization:joint session APDIO-SEIO5 de Setembro, 16:30 - 18:20Sala: 23.3.5

Organização: Tatiana Tchemisova e Margarita Rodriguez ÁlvarezModeradora: Tatiana Tchemisova

On Finite Linear Systems Containing Strict Inequalities

Margarita Rodríguez Álvarez, José Vicente Pérez

Resumo. This talk deals with linear systems containing finitely manyweak and/or strict inequalities, whose solution sets are referred to as evenlyconvex polyhedral sets. The classical Motzkin theorem states that every(closed and convex) polyhedron is the Minkowski sum of a convex hull offinitely many points and a finitely generated cone. In this sense, similar rep-resentations for evenly convex polyhedra have been recently given by using thestandard version for classical polyhedra. In this work, we provide a new dualtool that completely characterizes finite linear systems containing strict in-equalities and it constitutes the key for obtaining a generalization of Motzkintheorem for evenly convex polyhedra.

From applications to methods for constrained fractional quadraticproblems

Paula Amaral

Resumo. In this talk we show many important applications of Con-strained Fractional Quadratic Problems, from Statistics, to Economics, tothe repair of Inconsistent Systems. We discuss the difficulties in addressingthis problem and present some successful contribution from copositive opti-mization. We show that even for small instances related to data classificationthe optimality certificated is only achieved using lower bounds provided bythe relaxation of copositive reformulations.

Converse and total duality for evenly convex optimizationproblems

Maria Dolores Fajardo, Jose Vidal

Resumo. By means of a conjugation scheme based on generalized convex

26 Sessão W2: Continuous Optimization: joint session APDIO-SEIO

conjugation theory, instead of Fenchel conjugation, we build an alternativedual problem for a general optimization one defined on a separated locallyconvex topological space, using the perturbational approach. Sufficient con-ditions for converse and total duality involving the even convexity of theperturbation function are established.

Calibration of parameters in Dynamic Energy Budget modelsusing Direct-Search methods

Ana Luísa Custodio, Jéssica Morais, Gonçalo Marques

Resumo. Dynamic Energy Budget (DEB) theory aims to capture thequantitative aspects of metabolism at the individual level, for all species. Theparametrization of a DEB model is based on information obtained throughthe observation of natural populations and experimental research. Currentlythe DEB toolbox estimates these parameters using the Nelder-Mead Sim-plex method, a derivative-free direct-search method. However, this proce-dure presents some limitations regarding convergence and how to addressconstraints.

Framed in the calibration of parameters in DEB theory, this work presentsa numerical comparison between the Nelder-Mead Simplex method and theSID-PSM algorithm, a Directional Direct-Search method for which conver-gence can be established both for unconstrained and constrained problems.A hybrid version of the two methods, named as Simplex Directional Direct-Search, provides a robust and efficient algorithm, able to solve the constrainedoptimization problems resulting from the parametrization of the biologicalmodels.

On a new approach to optimality in Copositive Programming

Tatiana Tchemisova

Resumo. The talk is devoted to new optimality conditions for linearproblems of Copositive Programming. We transform the linear copositiveproblem to a convex Semi-infinite Programming problem for which we applythe results on CQ-free optimality conditions obtained using the notions ofimmobile indices and the corresponding optimality conditions. As a result,we obtain new optimality conditions for Copositive Programming, which arealso CQ-free. We show that these conditions are more efficient when comparedwith the known results for the same classes of problems.

Sessão W3: Supply Chain and Production Management I * 27

Sessão W3: Supply Chain and ProductionManagement I *5 de Setembro, Quarta-feira, 16:30 - 18:20Sala: 23.3.9

Moderadora: Margarida Vaz Pato

Supply Chain Resilience: An optimisation model to identify therelative importance of SC disturbances

João Pires Ribeiro, Ana Barbosa-Póvoa

Resumo. Supply Chains (SC) have been facing a vast set of events thatcan endanger their operations and produce permanent damage, which areunknown until its occurrence. This led to an increased awareness of SC Re-silience to deal with such SC uncertainty. This work uses a Mixed IntegerLinear Programming model to study the relative importance of the differ-ent types of events that threaten SC operations. From this work, it can besaid that upstream disturbances are of greater importance and are the eventsthat should be more efficiently managed, generating value and ultimately acompetitive advantage to companies that deploy resilience concerns to theiroperations.

Supply chain purchasing domain optimization in a Portugueseretail company

Ana Teixeira, Eliana Costa e Silva, Isabel Cristina Lopes

Resumo. In this paper we address a case study of the purchasing manage-ment section in a Portuguese company in the Retail sector. The purchasingmanagement costs in this company were found to depend largely on the stor-age mode of the products. Therefore we developed a mathematical model foroptimizing the purchasing management costs. In the model we address howto order the products and which storage mode to choose, in order to minimizecosts and fulfil the demand. Real instances regarding the monthly demand forone year are tested and the results show that the model can reduce the ratiobetween operational costs and merchandise costs in almost every instance.

28 Sessão W3: Supply Chain and Production Management I *

On the selection of the best distribution for inventorymanagement of intermittent demand items in healthcare

Luís Girão, Gonçalo Figueira, Mário Amorim-Lopes

Resumo. In healthcare institutions a stock out occasion could, in theworst scenario, represent a loss of a patient life. Furthermore, the cost ofsome items is very high, making it necessary to minimize the amount of capitalinvested in these goods. Healthcare drugs and material for clinical consump-tion face different demand patterns. These patterns could be smooth, erratic,intermittent or lumpy. The percentage of items facing intermittent demandis high. These products have large inter-demand intervals. This behavioris also typical of spare parts items and makes inventory management moredifficult. The demand during the lead time is crucial for the determinationof the parameters of inventory management policies. For intermittent items,there are a few studies trying to find the right distribution that fits the leadtime demand which guarantees the best service level. One of them proposeda modified Kolmogorov Smirnov test, which weighs more the right tail of thedistribution. This work replicates these previous studies by applying the samemethods to a real dataset collected from a large urban multi-specialty hospi-tal. The main goal is to assess whether the conclusions of the previous worksare still valid on a new dataset from a different area.

Managing the product line: bridging marketing and operations

Xavier Andrade, Luís Guimarães, Gonçalo Figueira

Resumo. The selection of a product line appeals to revenue manage-ment and operations planning. Nevertheless, this decision is frequently madeunilaterally by marketing teams, underestimating the potential costs and syn-ergies that might arise in operations. We present a novel mixed-integer linearmodel that aims to conciliate the viewpoints of marketing and operations inthe choice of a product line. We develop a linear formulation for a demandmodel to tackle the weaknesses of the dominating models in the literature.We find the value of integrating the decision of the two departments, andthat of the new demand model. Finally, we propose extensions to the model,improving its flexibility and ensuring its applicability In real-world scenarios.

Sessão W4: Logistics Allocation Problems 29

Um modelo tri-objetivo para redesenho da rede de uma cadeiade abastecimento de bancos alimentares

Margarida Vaz Pato, Carlos Martins, Teresa Melo

Resumo. O problema abordado nesta apresentação refere-se ao redesenhoda rede multinível de uma cadeia de abastecimento de bancos alimentares. Asdecisões envolvidas incluem abertura e encerramento de bancos alimentares,bem como escolha das respetivas capacidades de armazenamento e de trans-porte ao longo de um horizonte de planeamento multi-período Selecionam-seas novas instituições beneficiárias a apoiar pela cadeia de bancos, determina-sea afetação de todas as instituições apoiadas a algum dos bancos e distribuem-se os produtos alimentares doados pelas instituições. Admite-se fluxo multi-produto dos doadores para os bancos, entre bancos da rede e dos bancos paraas instituições. Admite-se também que as doações são insuficientes para satis-fazer a procura das instituições. Tendo em vista a sustentabilidade da opera-ção são considerados três objetivos: minimização do custo operativo da redede bancos alimentares; minimização dos impactos ambientais do desperdícioalimentar e das emissões de CO2; e maximização dos benefícios sociais ge-rados através do apoio às instituições e do trabalho voluntário criado. Seráapresentado um modelo de otimização tri-objetivo linear inteiro misto, bemcomo resultados computacionais obtidos a partir de instâncias representativasda rede gerida pela Federação Portuguesa de Bancos Alimentares.

Sessão W4: Logistics Allocation Problems5 de Setembro, Quarta-feira, 16:30 - 18:20Sala: 23.3.10

Moderador: José Soeiro Ferreira

Layout Optimization for a real world stock warehouse - Thenon-food sector

Maria Alice Trindade, Maria Rosário Alves Moreira, PauloSérgio Amaral de Sousa

Resumo. Retail industry sector is becoming increasingly competitive. Asa result, led by pressures for reducing costs, improving quality and responsive-ness created by the global competition, companies are seeking to squeeze in-efficiencies out of their supply chains. Consequently, to optimize a company’soperations sector, have become a permanent concern. This paper emerges as

30 Sessão W4: Logistics Allocation Problems

a way to improve the internal layout of the non-food sector zone of the northwarehouse region of a Portuguese Food Retailer company.

At a first stage, we manage to collect information about the non-food stockprocesses throughout informal interviews, non-participant observation anddata about the items in stock and its locations. At a second stage, we redesignthe layout of the non-food stock section of the warehouse by formulating amathematical programming model that classifies the stock and helps us todistinguish the warehouse products between slow and fast movers, having asmain criteria their own turnover. This classification will be further used toaccess the optimal location for the items on warehouse and the improvementof the pickers’ productivity while building the pallets for the stores.

The manufacturer’s pallet loading problem with stability andcomplexity constraints – A case study

Galrão Ramos, Elsa Silva, Pedro Lopes, Pedro Ribeiro

Resumo. The manufacturer’s pallet loading problem is frequently ad-dressed by reducing the three-dimensional problem to a two-dimensional one,since usually boxes can only rotate about a vertical axis. However, this meansthat practical additional constraints such as stability or complexity, are nottaken into consideration when determining the two dimensional layout ar-rangement, limiting the applicability of such solutions in practice. This workpresents a flexible heuristic algorithm that enforces stability constraints basedon criteria defined by the user while addressing complexity constraints thatemerge from the automated robot packing. The algorithm was developed aspart of the AdaptPack project which developed a framework focused on thedesign and development of new highly flexible modular robotic packaging andpalletizing systems. The algorithm was tested using a large set of real worldinstances from an industrial company, and the results were compared to thecurrent solutions of the company and were also validated by the company.

The container loading problem in a shoes manufacturer

Manuel V.C. Vieira

Resumo. In this talks we describe a real life application of a containerloading problem for a shoes manufacturer. Shoe boxes are packed in severalcardboard boxes with variable dimensions. We present a MINLP model whichdecides how to pack the shoe boxes and the size of cardboard boxes. Thiscontainer loading problem is classified as an open dimension problem, withthree open dimensions. We approximate the MINLP model with a MILP andwe compare it by using BARON on the nonlinear model and we run CPLEX

Sessão W5: Multicriteria Decision Making * 31

on the linear model.

Optimizing shelf space allocation under merchandising rules

Luís Souto, Teresa Bianchi-Aguiar, José Fernando Oliveira

Resumo. The allocation of products to shelves is a very challenging prob-lem that retailers face on a regular basis. In retail environments, products aretypically grouped into product families (blocks), and a set of merchandisingrules is then defined. These rules will determine how product families shouldbe arranged on the shelves, according to a multi-level hierarchical structure.Their purpose is to improve in-store experience by trying to reproduce theway consumers look for products while shopping, enhancing the shelves’ at-tractiveness. However, merchandising rules lead to a highly constrained andcombinatorial shelf space allocation problem. To tackle it, a heuristic algo-rithm consisting of a constructive and an improvement stage was developed.The constructive procedure explores the problem’s inherent hierarchical na-ture and the improvement heuristic combines local search techniques withperturbation mechanisms. The performance of the algorithm was tested ona set of benchmark instances from a European grocery retailer. When com-pared with state-of-the-art methods, our method yielded satisfactory resultswithin shorter computation times.

Sessão W5: Multicriteria Decision Making *5 de Setembro, Quarta-feira, 16:30 - 18:20Sala: 23.3.14

Moderador: José Rui Figueira

Enhancing participatory decision-making in Energy through theENERPHI platform

Ana Vieira Vieira, Mónica Oliveira, João Bana e Costa, CarlosBana e Costa

Resumo. Decision-making in the energy sector is typically characterizedby uncertainty, risk and the existence of multiple objectives which raises sev-eral challenges. One of such challenges is the involvement of energy expertsand stakeholders from multiple disciplinary fields, backgrounds and levels of(power of) decision in the development of tailor-made evaluation models. Thisparticipatory involvement is important to gather knowledge and to increase

32 Sessão W5: Multicriteria Decision Making *

decisions’ legitimacy, but poses several difficulties regarding the way to col-lect and include the participants’ values and perspectives. For cost, time andefficiency reasons, there is space for developing innovative technologies to en-hance participation in non-face-to-face formats. In this presentation we willpresent the ENERPHI platform (http://enerphi.tecnico.ulisboa.pt/) whichpromotes a Web-Delphi platform to enable participatory processes in energydecision-making contexts and which provides attractive and intuitive audio-visual pedagogical tutorials to enable its use through a hands-on-approach.We will present real cases where ENERPHI has been used (e.g. to survey en-ergetic efficiency of the Lisbon Hotel community, for prioritizing measures forthe implementation of the Brazilian Nationally Determined Contribution re-garding the Paris agreement, and for educating engineers in decision supportmodelling) and discuss the advantages of using the platform for promotingparticipation within multicriteria evaluation.

MCDA approach for the supplier selection in the healthcareunits in Portugal: the case of heavy medical equipment

Mafalda Prazeres, José Rui Figueira, Rui Marques

Resumo. Medical devices, in particular the heavy set, are equipment withvery high technological levels, which contributes significantly to the qualityof healthcare services in medical diagnosis, monitoring and even therapeutics.In this context, the focus is on the sustainable supplier selection, in order toselect the equipment that best meets the requirements of a given service. Forsuch purpose, a value based MCDA approach is used adapting the Choquetintegral to assess criteria interactions. The proposed methodology includes thefollowing two main steps: Firstly, assigning numerical values to the capacitiesof the Choquet integral, by constructing a ratio scale. Secondly, to constructinterval scales that reflect the utility values to the criteria performances. Inthe end, this application resulted in a set of ranking alternatives, orderedby preference, with the objective of identifying, and subsequently select, thesupplier (or his equipment) with the highest overall score. The results wereconsistent with those expected and analysis was carried out to prove therobustness of the model constructed as well as to study other variations inthe parameters considered.

Framework for the purchasing of radiology medical equipmentusing QFD and MCDA

Carolina Correia Ferreira, Maria Isabel Gomes

Resumo. Medical equipment is one of the largest spending in any Hos-pital budget. A comprehensive framework and policy for decision making in

Sessão W5: Multicriteria Decision Making * 33

purchasing, replacing and maintaining medical equipment is of even larger im-portance when considering State financed hospitals. The purpose of this workis to create tools for such decision-making process, through Quality FunctionDeployment (QFD), which will translate customer requirements into techni-cal, financial and service specifications, for each medical equipment. One ofthe major difficulties in the decision-making process is to assign a relative pri-ority for each purchasing or replacement request amongst all others. In orderto create this ranking, Multi-Criteria Decision Analysis model will be devel-oped based on pairwise comparisons, supported by the qualitative preferencejudgment gathered from QFD.

Difusão de veículos de combustível alternativo considerandopreferências dinâmicas

Gabriela Oliveira, Luís C. Dias

Resumo. Num contexto de difícil penetração no mercado de Veículos deCombustível Alternativo (VCA), os modelos de difusão têm sido um dos ins-trumentos mais utilizados para compreender e prever a procura destes veícu-los. As preferências dos consumidores têm um papel fundamental nestes mo-delos ao fornecer a informação necessária para suportar a previsão da procura.Apesar destas serem sempre consideradas como estáticas em estudos anteri-ores, as preferências de VCA são dinâmicas, ou seja, alteram-se aquando dealterações das condições de mercado. Sendo assim, modelar as preferênciascomo estáticas pode comprometer a sua adequação à análise de difusão. Nestecontexto, o objetivo deste estudo é incorporar preferências dinâmicas nummodelo de Sistemas Dinâmicos (SD) de VCA e analisar se a adaptação desubsídios a essas preferências permite obter melhores resultados quanto aoinvestimento e tempo necessário para alcançar metas delineadas. Foram as-sim implementados dois modelos de Sistemas Dinâmicos, um que consideroupreferências estáticas e outro que considerou as preferências dinâmicas. Os re-sultados revelaram que o modelo com preferências dinâmicas prevê uma maiorpenetração de mercado de VCA, o que mostra a sua relevância em previsõesde difusão de VCA.

Housing assignment of migrants in Turin: A multiple criteriaapproach

Ana Sara Costa, Isabella Maria Lami, Salvatore Greco, José RuiFigueira, José Borbinha

Resumo. In 2017, the number of international migrants worldwide wasthe highest ever recorded, reaching 258 million (United Nations, unpopula-tion.org). Migration is a universal and dramatic phenomenon that demands

34 Sessão W6: Risk Management and Uncertainty Modelling *

concrete answers. In this work, we present an application of a multiple criterianominal classification method, designated CAT-SD (inesc-id.pt/publications/13353/pdf), to tackle the problem of migrant accommodation in an Italiancity (Turin). As the majority of European cities, Turin offers to migrantstemporary places for a limited time span, which are insufficient and inade-quate; meanwhile, there are several abandoned buildings that can potentiallybe used to cover the needs of housing and facility of migrants. Our aim is tocontribute for defining an urban strategy and improving the decision- mak-ing process regarding the accommodation system. A co-constructive processthrough an interaction between the analysts and the experts is followed. TheCAT-SD method allows to identify the most adequate category or categories(representing distinct migrant status), considering several criteria, for eachabandoned building in Turin.

Acknowledgments: This work was supported by national funds through Fundação para a Ciência e a Tec-nologia (FCT) with reference UID/CEC/50021/2013. The first author acknowledges financial support from Uni-versidade de Lisboa, Instituto Superior Técnico, and CEG-IST (PhD Scholarship).

Sessão W6: Risk Management and UncertaintyModelling *5 de Setembro, Quarta-feira, 16:30 - 18:20Sala: 23.3.15

Moderador: Mário Amorim-Lopes

Conditional Value at Risk (CVaR) as a risk measure to supportindustrial plant design and scheduling decisions under demanduncertainty

Miguel Vieira, Helena Paulo, Tânia Pinto-Varela, Ana Barbosa-Póvoa

Resumo. Most decisions related to industrial plant design and scheduling,that strongly influences the financial performance of a company, are taken ina complex environment under uncertainty. Mathematical modelling has beenused to solve those problems considering stochastic programming, providingan expected objective value which does not allow control over critical prob-ability outcomes. Therefore, the risk assessment can integrate the trade-offsbetween the given objective and the risk profile of the decision maker. Condi-tional Value at Risk (CVaR) has demonstrated to be an effective risk metric,though its application in the problems in study is sparse and the influenceof the stochastic parameters is often not fully characterized. To address this

Sessão W6: Risk Management and Uncertainty Modelling * 35

problem, a two stage stochastic Mixed Integer Linear Programming modelthat considers the design and scheduling of a multipurpose batch plant isused. A bi-objective optimization approach maximizes the profit while min-imizing the risk using the e-constraint method. The generated Pareto curveis a valuable tool to support the decision-making process, with informationabout the different possible solutions in terms of profit and respective riskprofiles under demand uncertainty. The CVaR dependence of the nature ofthe stochastic parameters through different scenarios trees is also explored.

Robust Supply Chain Design under Supplier IntegrationUncertainty

Nuno Falcão e Cunha, Thiam-Soon Gan, Pedro Amorim,Bernardo Almada-Lobo, Martin Grünow

Resumo. Aerospace OEMs have prioritized the improvement of aircraftefficiency while concurrently reducing non-recurring costs in recent productdevelopment programmes. This was achieved by increasing the outsourcedcomponents and sharing R&D responsibilities with key suppliers. Supplierswere also asked to pre-assemble and integrate large aircraft systems. Thus,a new class of tier-1 strategic partners emerged and took on the role of "in-tegrators". The aggressive pursuit of this strategy introduced considerableuncertainty as integrators were asked to incorporate unproven technologiesto improve aircraft performance. This shift in responsibilities also demandedthat suppliers manage their own supply chains independently. We representthe likelihood of a supplier being disrupted due to technical or managerialissues as the supplier’s integration risk. We propose a collaborative productand supply chain design (CP-SCD) method for the OEM seeking an efficientsupply base under supplier integration risk. Robust optimization is used tomitigate uncertainty and to study how decision makers with different riskaversions should design their supply chains. Furthermore, we investigate howassigning multiple components to the same supplier and selective sourcingflexibility for different components affect the OEM’s exposure to risk.

Comparing approaches in Maritime Inventory Routing Problemwith uncertainty

Filipe Rodrigues, Agostinho Agra, Lars Magnus Hvattum,Marielle Christiansen

Resumo. Maritime transportation is one of the most common ways totransport goods. However, this kind of transportation is characterized by highlevels of uncertainty, since the weather conditions have a great impact in the

36 Sessão W6: Risk Management and Uncertainty Modelling *

sailing times. We consider a maritime inventory routing problem in which theproduction and consumption rates are constant over the planning horizon.The problem involves a heterogeneous fleet and multiple production and con-sumption ports with limited storage capacity. The impact of the uncertaintyin the sailing times is analysed according to five different approaches: deter-ministic model, deterministic model with safety stocks, robust optimization,stochastic programming, and a stochastic model using the conditional valueat risk measure. The non-deterministic approaches assume two-stage deci-sions, where the routing and the quantities to load/unload are fixed beforethe uncertainty is revealed, while the visit time to ports and the inventorylevels are adjusted to the scenario. For each approach, a mathematical formu-lation is proposed. An extensive computational comparison of the proposedapproaches, based on several quality parameters, is carried out over a set of 21instances. The obtained results show that substantial gains can be obtainedwhen the uncertainty is incorporated into the model.

Cohesive forest fire management in its socioecological context:intra-annual optimization of the prevention and suppressioninvestment mix under uncertainty

Abílio Pereira Pacheco, João Claro

Resumo. Increasing wildfire threats and costs escalate the complexity offorest fire management challenges, which is grounded in complex interactionsbetween ecological, social, economic and policy factors. It is immersed inthis difficult context that decision-makers must settle on an investment mixwithin a portfolio of available options, subject to limited funds and undergreat uncertainty. We model intra-annual fire management as a problem ofmultistage capacity investment in a portfolio of management resources, en-abling fuel treatments and fire preparedness. We consider wildfires as thedemand, with uncertainty in the severity of the fire season and in the occur-rence, time, place, and severity of specific fires. We analyze a hypotheticaltest landscape and derive policy insights and recommendations at operational(e.g., spatial solutions) and strategic levels (e.g., climate change). Exploringthe impact of increasing escape costs in the optimal investment mix, we iden-tified for our instances four qualitative system stages, which can be related tospecific socioecological contexts, and used as the basis for policy (re)design.In addition to questioning some popular myths, our results highlight the valueof fuel treatments and the contextual nature of the optimal portfolio mix.

Sessão W6: Risk Management and Uncertainty Modelling * 37

Enhancing optimization planning models for health humanresources management through scenario planning

Mónica Oliveira, Marta Barbas, Ana Barbosa-Póvoa, MarianaRaposo, António Alvarenga, Marco Alves, Mário Amorim-Lopes

Resumo. To ensure a balanced health workforce it is critical for healthpolicy-makers to plan the supply of health human resources (HHR). Mathe-matical programming models have been widely used to assist such planning,but sensitivity analysis typically shows that solutions are highly sensitive tochanges in uncertain parameters and stochastic solutions are difficult to in-terpret. This study proposes a new methodology that makes use of foresightand scenario planning concepts to enhance HHR management and planningthrough optimization models. The methodology embeds a transparent pro-cess for scenario building within an optimization model. Departing from theinput parameters of the planning model, health decision-makers or expertsare invited to engage into a scenario building process in which: they providepotential drivers for input parameters future variation in a web-platform; cog-nitive maps are used to cluster the drivers into key variables; morphologicalanalysis is used to create contrasted and meaningful scenarios; semi-structuredinterviews are used to adjust and validate scenarios; and finally a workshop isused to quantify future variations in input parameters, which are then used torun the HHR planning model for each scenario. The proposed methodologyhas been fully applied to inform HHR planning in Portugal.

38 Programa de 6 de Setembro

6 de Setembro (quinta-feira)

9:30 - 11:00

TA1 (sala 23.3.4): DEA and Performance Analysis I *TA2 (sala 23.3.5): Economics, Finance and Game TheoryTA3 (sala 23.3.9): Fleet Management and Transportation *TA4 (sala 23.3.10): Logistics in Healthcare *TA5 (sala 23.3.14): Metaheuristics for Scheduling Problems *TA6 (sala 23.3.15): Data Mining and Data Analysis *


11:30 - 13:20

TB1 (sala 23.3.4): Inventory ManagementTB2 (sala 23.3.5): Discrete Optimization and Graphs - Applications *TB3 (sala 23.3.9): Scheduling in Industry *TB4 (sala 23.3.10): OR in Health and Life SciencesTB5 (sala 23.3.14): Multiobjective Optimization I *

13:30 - 14:45 Almoço

15:00 - 16:00 Sessão Plenária 2 (sala 23.1.6): Bernardo Almada-Lobo

16:00 - 17:30

TC1 (sala 23.3.4): Decision Support Systems *TC2 (sala 23.3.5): Simulation and Optimization *TC3 (sala 23.3.9): Supply Chain and Production Management IITC4 (sala 23.3.10): Logistics and TransportationTC5 (sala 23.3.14): Multicriteria Decision Making - Methodology *TC6 (sala 23.3.15): Technology Management and Policy


17:45 - 18:45 Assembleia Geral da APDIO (sala 23.1.6)

19:30 - . . . Passeio de Moliceiro e Jantar do Congresso


Sessão TA1: DEA and Performance Analysis I * 39

Sessão TA1: DEA and Performance Analysis I*6 de Setembro, Quinta-feira, 9:30 - 11:00Sala: 23.3.4

Moderadora: Clara Bento Vaz

Hospitals funding: Optimizing tariffs for health care systemssustainability

Diogo Ferreira, Rui Marques

Resumo. In a number of countries around the world, hospitals are paidby the healthcare services they provide to the population. Different financ-ing systems are available, including the Beveridge and the Bismark models.Furthermore, payments can be either prospective, retrospective, or even amerging of them both. Even though, paid tariffs are usually non-optimal inthe Pareto sense, and disregard the quality of delivered services as well as theenvironment (either internal or external) in which hospitals operate. This gapmay introduce inefficiencies and inequalities in the healthcare systems, whichare currently facing scenarios of resources reduction or even scarcity. In otherwords, paid tariffs should be optimized in order to account for the missingdata. This study proposes a new best-practices based tool, applying it to thePortuguese National Health Service. Considerable cost savings may emergeif the model is successfully employed.

An alternative benchmarking approach for electricity utilityregulation using maximum entropy

Elvira Silva, Pedro Macedo, Isabel Soares

Resumo. The main purpose of this study is to present an alternativebenchmarking approach that can be used by national regulators of utilities.It is widely known that the lack of sizeable data sets limits the choice of thebenchmarking method and the specification of the model to set price controlswithin incentive-based regulation. Ill-posed frontier models are the problemthat some national regulators have been facing. Maximum entropy estimatorsare useful in the estimation of such ill-posed models, in particular in modelsexhibiting small sample sizes, collinearity and non-normal errors, as well as inmodels where the number of parameters to be estimated exceeds the numberof observations available. The empirical study involves a sample data used

40 Sessão TA1: DEA and Performance Analysis I *

by the Portuguese regulator of the electricity sector to set the parameters forthe electricity distribution companies in the regulatory period of 2012–2014.DEA and maximum entropy methods are applied and the efficiency resultsare compared.

Performance Evaluation of European Power Systems using DataEnvelopment Analysis

Mário Couto, Ana Camanho

Resumo. Electric power systems are facing significant challenges regard-ing their organiza-tion and structure. Energy infrastructures are crucial toensure a transition to low-carbon societies, contributing to sustainable devel-opment. This paper uses Data Envelopment Analysis to compare the per-formance of the electric power systems in 16 European countries using dataavailable to the public. Three perspectives were considered, focusing on tech-nical aspects affecting quality of service, net-work costs and environmentalimpact. These features are based on the models used for the regulation ofelectric utilities. The benchmarking results can give in-sights to electric op-erators, regulators and decision-makers on the strengths and weakness of theelectric power systems and disclose the potential for efficiency improvements.The discussion of the results is intended to raise public awareness on the effi-ciency of the European power systems and contribute to the definition of newpolicies for the promotion of continuous improvement.

Environmental performance assessment of European Countries

Clara Bento Vaz, Ângela Paula Ferreira

Resumo. The European Union (EU) has been promoting an integratedapproach to climate protection and energy policy, through a set of key objec-tives for 2020, 2030 and 2050, linking Europe’s green agenda with its need forenergy security and competitiveness. This paper aims to evaluate the environ-mental efficiency of European Countries from 2010 to 2015 towards these tar-gets, through a Data Envelopment Analysis (DEA) model. The DEA modelassesses the ability of each country in minimizing current resources whilemaximizing the gross domestic product and minimizing undesirable outputs,such as GhG emissions. The DEA model is based on Directional DistanceFunction, imposing weak disposability for the undesirable output. Resultsobtained show that globally, in the period under analysis, the EU has in-creased its environmental efficiency which is consistent with the analysis ofthe indicators of the 2020 climate and energy package.

Sessão TA2: Economics, Finance and Game Theory 41

Sessão TA2: Economics, Finance and GameTheory6 de Setembro, Quinta-feira, 9:30 - 11:00Sala: 23.3.5

Moderador: João Paulo Almeida

Modeling supply chain network: a need to incorporate financialconsiderations

Alexandra Borges, Dalila B.M.M. Fontes, José Fernando Gon-çalves

Resumo. In the past few years, important supply chain decisions havecaptured managerial interest. One of these decisions is the design of thesupply chain network incorporating financial considerations, based on theidea that all the establishment and operating costs have a direct effect oncompany’s financial performance. However, works on supply chain networkdesign (SCND) incorporating financial decisions are scarce. In this work, weaddress a SCND problem in which operational and investment decisions aremade in order to maximize the company value, measured by the EconomicValue Added, while respecting the usual operational constraints, as well asfinancial ratios and constraints. This work improves on current research byconsidering debt repayments and new capital entries as decision variables, aswell as improving on the calculation of some financial values, which leads togreater value creation.

Robust portfolio optimization with minimax regret: a new modeland a new methodology for calculating relative-robust solutions

Sandra Caçador, Joana Dias, Pedro Godinho

Resumo. A portfolio optimization model based on a new minimax regretmeasure is presented. Regret is defined as the utility loss for the investor, as-suming he has constant relative risk aversion preferences. To avoid reachinga solution strongly dependent on the underlying in-sample data, two sub-samples are gathered from the in-sample data: a training subsample used toestimate the inputs of the model and a validation subsample used to evaluateits performance. A genetic algorithm (GA) is applied for the computation

42 Sessão TA3: Fleet Management and Transportation *

of the relative-robust solution, allowing the transformation of a 3-level op-timization problem into a 2-level problem. The random generation of thesubsamples and the GA optimization are repeated several times, producingsets of different solutions and different validation subsamples. Each solutionis then tested using each one of the validation subsamples. The correspondingmaximum regret is computed. Relative-robust portfolio is defined as the onepresenting the best performance in the worst case, and is then tested in theout-of-sample set. The robustness of the model was confirmed concerning de-viations from its expected performance and utility loss for the investor. Theportfolio obtained with the presented methodology stands out as one of thevery few portfolios with no poor performances.

Location-Price competition in a network under uncertainty oncosts

João Almeida, Alberto Pinto

Resumo. We develop a theoretical framework to study the location-pricecompetition under uncertainty of firms’ production costs. Firms compete ina two-stage Hotelling-type network game, with linear transportation costs.We show the existence of a Bayesian-Nash equilibrium price if, and only if,some explicit conditions on the expected production costs and on the networkstructure hold. Furthermore, we prove that the local optimal location of thefirms are at the nodes of the network.

Sessão TA3: Fleet Management and Trans-portation *6 de Setembro, Quinta-feira, 9:30 - 11:00Sala: 23.3.9

Moderadora: Maria João Alves

Capacitated vehicle routing problem with heterogeneousfixed proprietary fleet and outsourcing delivery - A clustering-based approach

Ricardo Bertoluci, Galrão Ramos, Manuel Lopes, João Bastos

Resumo. This paper describes a decision support system that was cre-ated with the objective of obtaining a more efficient finished goods distribution

Sessão TA3: Fleet Management and Transportation * 43

process for a food industry company. The finished goods distribution process,involves the use of the company’s own fleet, to serve a specific group of cus-tomers, and the use of outsourcing transportation services, that can makedirect and transshipment customer deliveries. The complexity of the problemis due to the need to decide which customers should be served by each ofthe outsourcing transportation services, direct or transshipment, and to findcost efficient solutions for the several vehicle routing problems created. First,an original clustering method consisting of a logical division of the customerorders using a delivery ratio, based on the transportation unit cost, distanceand order weight, is used to define customer clusters by service type. Then,an exact method based on a mixed integer programming model, is used toobtain optimal vehicle routing solutions for each cluster created. The deci-sion support system proved for the company real instances, promising resultsthat suggests an average reduction of 34% for the operational costs, whencomparing to the current distribution model of the company.

An approach to solve the Capacitated Simultaneous Delivery andPick-up Problem

Ana Moura

Resumo. This work presents a Math-heuristic to solve a distributionproblem for a Portuguese company, with suppliers whose material flow isperformed in both directions. The objective is to determine a route with aminimal daily cost, for a vehicle that must collect and deliver cargo to mul-tiple suppliers – taking the vehicle’s capacity in terms of weight and volumeinto consideration. The contribution of this work involves the presentation ofa model-based heuristic that uses characteristics of two mixed-integer linearprogramming models to solve this distribution problem. The first mathemat-ical programming model represents an asymmetric commodity-flow model forthe Vehicle Routing Problem with Simultaneous Delivery and Pick-up withTime Windows and the second one, a 3-Dimensional Packing Problem. Then,a model-based heuristic is also presented, using the same exact mixed-integerlinear programming models to achieve efficient solutions, in a reduced compu-tational time. Using real data from the company, several problem tests weredesigned. In order to test the feasibility and viability of the mixed-integerlinear programming models and the model-based approach, some benchmarkproblem instances were also used.

44 Sessão TA3: Fleet Management and Transportation *

Stochastic capacity-pricing problem in car rental: co-generatingsolutions and scenarios

Beatriz B. Oliveira, Maria Antónia Carravilla, José FernandoOliveira, Alysson M. Costa

Resumo. When planning a selling season, a car rental company mustdecide on the number of vehicles of each group it will have to meet demand.The products are the rental types, characterized by start and end time, lo-cation and vehicle group required. The demand for them is uncertain andhighly price-sensitive, interconnecting the prices charged and the capacitydecisions. Throughout the season, the company must also make other fleet-related decisions, such as fleet deployment. This problem is modeled as a two-stage stochastic program. The goal of this work is to provide decision-makerswith profitable solutions to the first stage decisions, describing their ability todeal with different realizations of uncertainty, represented by scenarios. Themethodology developed is based on a co-evolutionary genetic algorithm, whereparallel populations of solutions and scenarios co-evolve, depending on eachother for fitness evaluation. This method obtains a representative and diversepopulation of scenarios, in relation to the impact they have on solutions, andsolutions that converge to well-performing decisions, based on different riskprofiles, clearly associated with the impact of the different scenarios.

Afetação de veículos e motoristas na gestão de viagens de serviçonuma Universidade Brasileira

Filipe Monnerat, Maria João Alves, Joana Dias

Resumo. Este trabalho trata um problema de afetação de veículos e mo-toristas para satisfazer um conjunto de requisições de viagens realizadas numdeterminado horizonte temporal, tendo como objetivo a minimização dos cus-tos totais. O trabalho foi motivado por um caso real de uma Universidadebrasileira que tem a sua própria frota de veículos e motoristas que devem serafetados a requisições de viagens de serviço, assegurando que todas são feitasnos períodos de tempo desejados. As viagens são caracterizadas por umahora de partida, locais de início e fim, distância e hora de viagem, número demotoristas necessários para cada veículo escolhido e número de passageiros.Apresenta-se o modelo matemático desenvolvido, que é uma extensão do mo-delo de afetação generalizado, incorporando vários aspetos diferentes do pro-blema real, como a possibilidade de veículos serem compartilhados entre di-ferentes viagens, se as viagens ocorrem em intervalos de tempo compatíveis etêm destinos compatíveis. Apresentam-se também resultados computacionaisconsiderando o estudo de caso que motivou a investigação deste problema,

Sessão TA4: Logistics in HealthCare * 45

analisando-se as soluções obtidas. É possível concluir que permitir a partilhade veículos por várias viagens permite aumentar a ocupação total dos veículos,resultando numa melhor utilização dos recursos disponíveis.

Sessão TA4: Logistics in HealthCare *6 de Setembro, Quinta-feira, 9:30 - 11:00Sala: 23.3.10

Moderadora: Maria Eugénia Captivo

A Column Generation-based Diving Heuristic for StaffScheduling at an Emergency Medical Service

Hendrik Vermuyten, Joana Namorado Rosa, Inês Marques,Jeroen Beliën, Ana Barbosa-Póvoa

Resumo. Staff scheduling involves assigning people to tasks organizedin working shifts. It is a complex and time-consuming activity common toseveral real-world companies while still typically a hand-made task. Theseproblems are usually conditioned by legal and working rules, and by personalpreferences. Thus, the challenge is to find schedules that most accurately fitthe functionality of the services and equity issues. For this purpose, a columngeneration-based diving heuristic is proposed to solve a staff scheduling prob-lem at an Emergency Medical Service. The approach is generic and possiblyadjusted to several realities and companies. In this context, the heuristic isapplied to a real-life problem at Instituto Nacional de Emergência Médica(INEM), obtaining good quality solutions in relatively short running times.The best-found solution is compared with an implemented schedule at INEM,strengthening the practical value of this approach. The ultimate goal is todevelop automated tools to support INEM in their staff scheduling activities.

Localização ótima de ambulâncias: uma abordagem tendo emconta hierarquia e substituibilidade de recursos

José Nelas, Joana Dias

Resumo. Neste trabalho apresentar-se-á um modelo de localização deambulâncias, que tem explicitamente em conta a existência de equipamentoscom diferentes características de socorro e transporte de passageiros, e ainda a

46 Sessão TA4: Logistics in HealthCare *

capacidade que alguns equipamentos têm de substituírem outros. Considera-se um modelo de cobertura que pretende maximizar o número total de episó-dios cobertos. Assume-se que um episódio está coberto se e só se recebeu emtempo útil todos os meios que eram necessários (que poderão ser de diferentestipos). O modelo considera explicitamente restrições de capacidade associadaaos equipamentos, garantindo que um dado equipamento não pode estar aatender mais do que um episódio simultaneamente, permitindo ter em contatempos de viagem e de preparação dos equipamentos depois de cada episó-dio. É também possível considerar que nem todos os veículos estarão sempredisponíveis, mesmo quando não estão afetos a episódios de emergência. Serãoainda discutidas várias vertentes de trabalho futuro, que se prendem com aintrodução de outros tipos de objetivos/restrições no modelo: maximização daequidade, possibilidade de cobertura parcial, análise de compromissos custosversus tempos máximos de atendimento, entre outros.

Setorização aplicada ao transporte de utentes não urgentes entreresidências e centros hospitalares

Ana Maria Rodrigues, Luís Miguel Bandeira, José SoeiroFerreira

Resumo. Os Problemas de Setorização (PS) consistem, em linhas gerais,na divisão de um território de maiores dimensões em territórios mais pe-quenos, onde certas condições específicas são respeitadas. Aplicações surgem,entre outras, no desenho de distritos políticos, na definição de territórios devendas, em problemas de policiamento ou de limpeza de ruas. Na Sectoriza-ção são usados diversos critérios, tais como, o equilíbrio, a contiguidade e acompacidade. Os autores propõem-se apresentar uma aplicação real de umPS ligado ao transporte de utentes entre as suas residências e centros hospi-talares. A setorização deverá ter em conta, entre outros, aspetos relacionadoscom o sentido de transporte (residência-hospital ou hospital-residência) e olocal das refeições. A resolução será baseada numa adaptação do SectorEl –Sectorization by Electrostatics - um método desenvolvido pelos autores.

Heuristics for scheduling elective surgeries in a public hospital

Maria Eugénia Captivo, Carolina Martins, Raquel Sousa

Resumo. e study the elective surgeries scheduling problem in a Por-tuguese public hospital. The operating room represents a large part of theexpenses and profits of any hospital, so the efficiency in its use is fundamen-tal. Also, as a consequence of the inability of the hospital units to respondto the increase in the demand for surgeries, the waiting lists for surgery are

Sessão TA5: Metaheuristics for Scheduling Problems * 47

very large. So, their reduction is one of the main objectives of the NationalHealth Service. The administration of the hospital aims to achieve the tar-gets set by the Portuguese Ministry of Health for surgical production and toensure a surgical service with a high level of efficiency. However, hospitalsdo not have an elective surgery scheduling system, so surgeries are scheduledin a non-systematical manner and without respecting equity criteria. Heuris-tics to find quickly good solutions for the problem are developed, consideringdifferent criteria. The heuristics select patients from a long waiting list forsurgery to be scheduled in each week, and define a room and a day for eachselected surgery according to one of the criteria. Tests with real instances arepresented and analyzed. A user-friendly interface for the hospital is underdevelopment.

Sessão TA5: Metaheuristics for SchedulingProblems *6 de Setembro, Quinta-feira, 9:30 - 11:00Sala: 23.3.14

Moderadora: Ana Barbosa-Póvoa

Parallel Machine Scheduling in “Human-Robot Collaboration”Assembly Environments

Cristiane Ferreira, Francisco Machado, Gonçalo Figueira, PedroAmorim

Resumo. The term “Human-Robot Collaboration” has been used to de-fine different types of industrial environments where humans and robots sharethe same workplace. These hybrid teams are usually characterized by theheterogeneous performance of resources and the possibility to jointly executetasks.

In this work, we aim to analyze how the application of operational re-search methods to these new hybrid environments could provide importantmanagerial insights regarding the task design. For that we present a gen-eralization of the Parallel Machine Scheduling Problem where jobs may beexecuted by two different types of resources (humans and robots) or even byboth simultaneously.

We implemented a Constraint Programming model that is capable of find-ing the optimal solution for most of the problem instances generated. More-over, a Linear Programming model provided tight lower bounds for the un-solved instances. In order to generate good quality solutions for the set of

48 Sessão TA5: Metaheuristics for Scheduling Problems *

larger instances we propose two meta-heuristics: a Genetic Algorithm and aTabu Search. They have resulted in an average gap of 0.14% to the optimalsolutions and 13% to the lower bounds.

Experiments show that the possibility of collaborative work can providelarge improvement opportunities, particularly in settings with low automationand high levels of precedence constraints.

A hybrid methodology for jobs scheduling on a reconfigurableassembly line

Isabela Maganha, Marcel Da Silva Van Der Kroef, CristóvãoSilva, Nathalie Klément

Resumo. Manufacturing systems must be increasingly intelligent and re-configurable to react to changes rapidly and cost-effectively. Technologicaladvances, as internet of things, mobile robots and cyber-physical systems,support ready reconfiguration and have been contributing to design reconfig-urable manufacturing systems. In this study we present a problem associatedto a reconfigurable assembly line, composed by 10 workstations, where twodifferent products must be assembled. For each product a set of operation isto be performed at each station. Products A and B have common operationswhich are performed by humans. But, each product has their specific oper-ations which are performed by mobile robots that can move among worksta-tions whenever necessary, thus, characterizing a highly reconfigurable system.The problem can be stated as follow: a set of jobs (A and B) has to be as-sembled in the line. Each job is composed by a set of specific operations tobe performed by mobile robots in each workstation. The problem consists indefining a schedule for the jobs, deciding which robot will be assigned to whichworkstation to perform which operation, in order to minimize the makespan.The problem is solved by a methodology which combines a list algorithm anda metaheuristic.

Modelação e Otimização de um problema operacional dere-escalonamento de impressões

Nelson Chibeles-Martins, Mónica Lencastre

Resumo. A empresa X é uma gráfica da zona da Grande Lisboa. Umdos problemas diários que a Direção de Produção enfrenta é o escalonamentodas várias tarefas de impressão às diferentes impressoras disponíveis. O queaparentava ser um típico problema de Escalonamento veio a revelar-se algomais desafiante. Durante o dia, podem chegar à Produção, a qualquer mo-mento, novas ordens de impressão e os responsáveis têm de decidir:

- em que impressoras e quando deverão ser realizadas estas novas ordens;

Sessão TA6: Data Mining and Data Analysis * 49

- e se valerá a pena interromper, ou não, alguma das tarefas que já seencontra a decorrer.

Estas decisões são tomadas operacionalmente, de forma regular, mas nuncahouve uma avaliação do seu impacto a nível de custos e de desperdício demeios.

Neste trabalho pretende-se mostrar as metodologias utilizadas na simplifi-cação e modelação deste problema, no tratamento das informações recolhidase no desenvolvimento de uma ferramenta heurística que possa ser utilizadacomo apoio na tomada das decisões acima referidas.

Escalonamento de linhas de produção flexíveis com utilização derobots

Joana Guapo, Miguel Vieira, Tânia Pinto-Varela, Ana Barbosa-Póvoa

Resumo. A colocar a quarta revolução industrial está a estabelecer novosdesafios para a otimização dos processos. A automação das instalações comsistemas tecnológicos avançados é uma realidade que potencia a competitivi-dade e a capacidade de resposta à variabilidade da procura no mercado, tendocomo objetivo a mitigação da incerteza operacional. Além disso, os sistemasde programação tradicionais foram substituídos por sistemas de gestão inte-grados, muitas vezes em tempo real, para permitir o incremento de eficiêncianas operações de sistemas de manufatura flexíveis. Estas novas abordagensresultam num incremento computacional, uma vez que este tipo de problemassão NP-difíceis. Neste trabalho é implementada uma meta-heurística (Parti-cle swarm optimisation) no âmbito de escalonamento de linhas de produçãoflexíveis, explorando a integração da colaboração robot-humano, com o obje-tivo de: minimização dos custos de produção, inventário, ordens em atraso,e do número de robots utilizados nas linhas de produção. O desempenho dameta-heurística PSO é ilustrado através de um caso de estudo, cujos resulta-dos são comparando com uma metodologia exata.

Sessão TA6: Data Mining and Data Analysis *6 de Setembro, Quinta-feira, 9:30 - 11:00Sala: 23.3.15

Moderador: Gonçalo Figueira

50 Sessão TA6: Data Mining and Data Analysis *

Use of Machine Learning Techniques in the Banking Credit RiskAnalysis

Maria Teresinha Steiner, Amanda Trojan Fenerich, Pedro JoséSteiner Neto, Edevar André Tochetto, Diego Paolo Tsutsumi,Fernanda Medeiros Assef

Resumo. The purpose of this article is to compare the performance of acredit scoring model by applying different techniques of Machine Learning forclassification of payers in bank financing of companies. The historical recordsof credit operations carried out by 5,432 companies. It was considered “non-default” or “default” clients depending on the default rate, calculated from thenumber of operations with payments on time and the number of operationsdelayed for more than 180 days. In this way, 4,238 considered “non-default”and 1,194 “default”. For each case total of 10 attributes (variables; features)were retrieved. First of all a random undersampling technique was applied,in order to solve the unbalanced data problem. After that, the variableswere coded by two ways: code I (categorical variables) and code II (dummiesvariables). In the sequence, it was performed the feature selection methodsin order to detect which could be the most important variables. Finally, weused the classifier algorithms: Bayesian Networks (BN); Decision Tree (DT)and Support Vector Machine (SVM). All these techniques were implementedin the WEKA (Waikato Environment for Knowledge Analysis) software. Theaccuracies of the models were 0.89; 0.952 and 0.93, respectively.

Forecasting financial time series: a comparative study

Anabela Costa, Filipe Ramos, Diana Mendes, Vivaldo Mendes

Resumo. The main purpose of this paper it is to show that machinelearning methods (neural networks and k-nearest neighbors) can be used touncover the non-linearity that exists in financial time series and provide highquality forecast. First, we analyse the linearity (BDS test) and stationarity(ADF, PP unit rot test) of the Portuguese stock market index, PSI20, andalso some typical features are studied (descriptive statistics, Hurst exponents,among others). The first forecast it is provided by traditional linear ARMAmodels. Secondly, we train several types of neural networks for the PSI20index and use the models to make 1 and 5-day forecasts. The artificial neuralnetworks are obtained by using a three-layer feed-forward topology and theback-propagation learning algorithm. Thirdly, k-nearest neighbors chartistmethod it is used. Finally, we compare the out-of-sample forecast error (MAE)for the several models, in order to conclude about the forecasting performance.

Sessão TA6: Data Mining and Data Analysis * 51

Classification Algorithms in Financial Application: Credit RiskAnalysis on Companies

Maria Teresinha Steiner, Fernanda Medeiros Assef, Pedro JoséSteiner Neto, David Gabriel de Barros Franco, Edevar AndréTochetto, Amanda Trojan Fenerich

Resumo. This research aims at analyzing bank credit for companies, con-sidering three different outcomes for a single operation (non-default, past-dueand default operations), for the purpose of assisting decisions made by ana-lysts at bank credit evaluation area. It was considered as non-default client,those who make their payments in time; past-due clients, those who delayedtheir payments from 1 to 180 days; and default, those who have failed formore than 180 days in their payments. The models used in order to fore-cast customer situation were developed using an Artificial Neural Networks(ANNs), more specifically, the Multiple Layer Perceptron (MLP); the Ra-dial Basis Functions (RBF) and, also, the Logistic Regression (LR) statisticalmodel. For the implementation of these techniques, the softwares MATLABand SPSS were used, respectively. For the development, a set of 5,432 op-erations was used, collecting 15 attributes for each one. From the total of5,432 instances, 2,600 were considered as non-default; 1,551 were consideredpast-due and 1,281 default clients. The results show that the default clientsare easily identifiable (with accuracies of 91.40%; 80.72% and 88.50% throughMLP, RBF and LR, respectively).

Demand forecasting in a multi-specialty hospital setting: a com-parative study of machine learning and classical statistical methods

Carlos Alves, Sofia Cruz-Gomes, Luís Girão, Gonçalo Figueira,Mário Amorim-Lopes

Resumo. Forecasting demand is a critical step in ensuring an effectiveand efficient delivery of healthcare. From an inventory management perspec-tive the relevance is two-fold: 1) to ensure that both pharmaceuticals andclinical material are available, avoiding shortages of consumables during treat-ment; and 2) to reduce costs associated with unnecessarily high inventory andlosses of perishable items. Using data on the consumption history of a largeurban multi-specialty Portuguese hospital, we study the applicability of ma-chine learning algorithms to forecasting the demand for hospital consumables,which is paramount to efficient healthcare management, and compare them tomore traditional methods. In particular, we explore the performance of meth-ods such as Recurrent Neural Networks (RNN) and Support Vector Machines

52 Sessão TB1: Inventory Management

(SVM) with regards to parametric methods such as the Holt-Winters Expo-nential Smoothing or Auto-regressive Integrated Moving Average (ARIMA).We generalize the results by identifying the properties that make one modelmore suitable for a given category of items.

Sessão TB1: Inventory Management6 de Setembro, Quinta-feira, 11:30 - 13:20Sala: 23.3.4

Moderador: Agostinho Agra

Semi-variance as a safety stock calculation principle

Gerrit K. Janssens, Katrien Ramaekers

Resumo. An inventory system containing uncertainty in demand duringlead-time requires to determine a safety inventory for re-ordering. The deci-sion models need a probability distribution of the demand during lead-time.Many textbooks on inventory control propose to use a Normal distributionfor describing the demand during lead-time. Based on the knowledge of thestandard deviation and on the distribution assumption, the safety inventory iscalculated, given a prescribed customer service level. However, the functionalform of the probability distribution in practice might look different from theshape of a Normal distribution and by this wrong decisions are made whichresult in high costs or low service level. In other disciplines other risk measuresthan the standard deviation have been used. One of these is the principle ofsemi-variance. This research investigates whether the use of semi-variance isa valid alternative for the standard deviation in the determination of safetystock. The investigation is tested on compound Poisson distributed and ontriangular distributed lead-time demand.

An Integrated Model of Supplier Selection and InventoryProblem under Supply Disruption

Thomy Eko Saputro, Gonçalo Figueira, Bernardo Almada-Lobo

Resumo. Procurement plays a central role in an enterprise’s performance.The success of procurement management depends on the coordination andintegration of activities. Supplier selection has to be made so as to sourcematerials with the right quality, in the right quantity, at the right time, and

Sessão TB1: Inventory Management 53

for the right price. The scope of this problem, as well as other aspects such asthe sourcing strategy, will depend on the type of items. Critical items, whichrepresent high-profit impacts and high supply risks, should be approachedcomprehensively by considering all the main activities of the procurementprocess. This work aims to study the supplier selection problem under a multi-sourcing strategy by integrating inventory management and order allocation.Most of the past studies do not mitigate the risk of supply. Thus, we considercomplex features such as supply disruptions. Since the disruptions cannotbe easily tackled by an exact approach, we apply simulation-optimization tosolve the problem. Specifically, we build a discrete event simulation model toevaluate the objective function and apply a genetic algorithm (GA) to solvethe supplier selection problem, while inventory decisions are determined byanalytical expressions. Finally, a numerical example is provided to illustratethe solution.

Evaluating the impact of committing to customer orders inonline retail

Gonçalo Figueira, Willem van Jaarsveld, Pedro Amorim, JanFransoo

Resumo. In online retail, customers place orders for a future due date.Therefore, there is a time window, which results in ‘advanced demand in-formation’ (ADI), that the retailer can use to better manage its inventory.Inventory management is performed in two different dimensions: the replen-ishment policy and the allocation policy. The allocation of specific units tocustomers affects the performance of the system in various metrics, such as fillrate, backorders and physical inventory. Moreover, some allocation policiescan be perceived as being unfair, which is critical when customer orders arerecurrent. In addition they can discourage customers to provide informationin advance, which reduces the advantage of ADI. We study different alloca-tion policies and evaluate the impact of committing upon order arrival. Theproposed policy is ‘fair’, optimizes fill rate and provides a better service levelto customers with longer lead-times, thus promoting ADI. When comparedto ‘committing upon delivery’, the new policy results in higher inventory andbackorders. However, the fact that the fill rate is improved has an importantimpact on operational costs, since it avoids additional deliveries. We pro-vide analytical results for the performance of different allocation policies andsimulate their behavior in a variety of scenarios.

54 Sessão TB1: Inventory Management

Robust approaches to inventory models

Agostinho Agra, Cristina Requejo, Filipe Rodrigues

Resumo. We consider a class of inventory Optimization problems wheredemands are uncertain. The demands can be satisfied by production, by in-ventory held in stock or backlogged. A recourse model is considered where theproduction decisions are first stage decisions and the stock and backlog levelsare adjustable to demands. For the uncertainty set, we consider the classicalbudget polytope. We revisit the two classical robust approaches: the truemin-max approach from Bienstock and Osbay (2008) and the dualization ap-proach from Bertsimas and Thiele (2006), and propose a new approach basedon the Lagrangean relaxation of the maximization sub-problem occurring inthe min-max approach. We show that this new approach is tractable and lessconservative than the dualization approach from Bertsimas and Thiele (2006).

A Decision Support System for the Definition of a Mixed Make-to-Stock/Make-to-Order Production Strategy

Manuel Marques, Paulo Sousa, Raquel Vieira, Pedro Schuller,José Oliveira

Resumo. This study was motivated by a manufacturer following a make-to-order strategy and facing difficulties to fulfill customer orders on time.This has a huge impact on the company since they incur in penalties for latedeliveries. While adopting a hybrid make-to-stock/make-to-order strategycould bring significant service level improvements, it is not so trivial to definethe ideal combination of both approaches, since the problem is combinatorialand policy changes introduced to one product have impact on the remainingproducts. We propose a methodology to redefine the production strategy, byselecting the ideal policy for each product, and to set an inventory planningapproach for make-to-stock products. The job-shop production environment,characterized by setup times, limited capacity and congestion effects, wasmodeled to assess the impact of changes to the strategy at the product level. Agreedy heuristic was developed to iteratively switch the manufacturing policyof individual products from make-to-order to make-to-stock. Selection of idealcandidates for policy change is based on an objective function that assessesthe cost trade-off between inventory and failed deliveries. By applying thedeveloped methodology, it is expected that the company increases on-timefulfillment rates while minimizing total cost.

Sessão TB2: Discrete Optimization and Graphs - Applications * 55

Sessão TB2: Discrete Optimization and Graphs- Applications *6 de Setembro, Quinta-feira, 11:30 - 13:20Sala: 23.3.5

Moderador: Filipe Alvelos

A Benders Decomposition Algorithm for the Berth AllocationProblem

Flávia Barbosa, José Fernando Oliveira, Maria Antónia Car-ravilla, Eduardo Curcio

Resumo. Benders decomposition is a cutting plane method that hasbeen widely used for solving large-scale mixed integer linear optimizationproblems. In this work, we review the basic Benders Decomposition algorithmand its variants. Moreover, we apply it to the reformulated Berth AllocationProblem. This is a NP-hard and large-scale problem that has been gainingrelevance in Operations Research and yet Benders Decomposition has neverbeen applied to it. The reformulation is based on the Heterogeneous VehicleRouting Problem with Time Windows (HVRPTW) model. Computationaltests are run to compare the proposed Benders Decomposition with a state-of-the-art commercial solver.

Políticas de teste de compatibilidade a priori em programas dedoação renal cruzada

Fábio Oliveira, Filipe Alvelos, Ana Viana

Resumo. Um programa de doação renal cruzada (Kidney Exchange Pro-gram – KEP) tem como objetivo facilitar a realização de transplantes renaispara pacientes com deficiência renal que têm alguém disposto a doar-lhes umrim, sendo tal impossível por incompatibilidade de tipos de sangue e/ou detecidos. Um KEP baseia-se num mecanismo de doação renal cruzada entrepares dador-recetor incompatíveis. É feito um primeiro estudo de compatibili-dade entre pares (crossmatch virtual), cuja informação é usada para construirum grafo representativo do KEP. Com base nesta informação e em mode-los de otimização (e.g. programação inteira) são planeados um conjunto detransplantes para os quais são realizados testes adicionais de compatibilidade

56 Sessão TB2: Discrete Optimization and Graphs - Applications *

(crossmatch) em laboratório antes de os transplantes serem efectivamente re-alizados. Caso sejam detectadas incompatibilidade, os transplantes envolvidosna troca do par em questão têm de ser cancelados. Neste trabalho, estuda-seo efeito no número de transplantes concretizados da realização de testes decrossmatch antes de o plano de transplantes ser definitivo. São propostas di-versas políticas para decidir quais os pares que devem ser selecionados paraos testes de crossmatch para os casos em que há e em que não há estimativasda probabilidade dos testes de crossmatch serem positivos.

A Dual-RAMP Algorithm for the Uncapacitated MultipleAllocation Hub Location Problem

Telmo Matos, Fábio Maia, Dorabela Gamboa

Resumo. Hub Location Problems (HLP) are complex combinatorial op-timization problems which general goal is to determine the set of hubs from allnodes in a given network in such a way that the allocation from all nodes tothe hubs is optimal. Being NP-Hard problems, using exact methods to solvelarge instances of these problems can be seriously compromised by the highcomputational times required to obtain the optimal solution. To overcomethis difficulty, a significant number of heuristic algorithms have been pro-posed with the purpose of finding good quality solutions in reasonable com-putational times. We propose a Relaxation Adaptive Memory Programming(RAMP) approach for the Uncapacitated Multiple Allocation Hub LocationProblem (UMAHLP) that explores the primal-dual relationship by combiningLagrangean Relaxation with Subgradient Optimization with an ImprovementMethod. The algorithm was tested on the Australian Post and the CivilAeronautics Boarding producing extremely competitive results. Comparisonswith the currently best-performing algorithms for the UMAHLP show thatour RAMP algorithm achieved excellent results.

Critical Node Detection with Connectivity based on BoundedPath Lengths

Fábio Barbosa, Agostinho Agra, Amaro de Sousa

Resumo. For a given graph representing a transparent optical network,a given weight associated to each node pair and a given positive integer c, theCritical Node Detection problem variant addressed here is the determinationof the set of c nodes that, if removed from the graph, minimizes the totalweight of the node pairs that remain connected. In the context of transpar-ent optical networks, a node pair is considered connected only if the survivingnetwork provides it with a shortest path not higher than a given positive value

Sessão TB3: Scheduling in Industry * 57

T representing the optical transparent reach of the network. Moreover, thelength of a path depends both on the length of its links and on its number ofhops. A path-based Integer Linear Programming model is presented togetherwith a Benders-like decomposition approach. We present computational re-sults for a real-world network topology with 50 nodes and 88 links and for c=2up to 6. The optimal results are compared with centrality based heuristicsshowing that such approaches provide solutions which are far from optimal.

Modelos de Programação Inteira Mista para Combate a FogosFlorestais

Filipe Alvelos

Resumo. Nesta apresentação aborda-se o problema de localizar recursospara o combate a fogos florestais. Parte-se do modelo de propagação de fogo“minimum travel time” (Finley 2002) em que é definida uma rede na qual osnodos estão associados a locais e os arcos a ser possível a propagação do fogoentre locais adjacentes. Dados os tempos de propagação do fogo associadosaos arcos, o tempo de chegada do fogo entre um local de ignição e um qual-quer local da rede corresponde à duração do caminho mais rápido entre osdois locais. Neste trabalho, em vez de utilizar algoritmos de caminho maiscurto (e.g. Dijkstra) modela-se a propagação do fogo através de programaçãolinear. Tal permite a integração de variáveis de decisão relativas à localizaçãode recursos na rede ao longo do tempo com vista à optimização de medidas deimpacto do fogo. Consideram-se e exemplificam-se quatro modelos de progra-mação inteira mista com os objectivos de i) maximizar o tempo de chegadado fogo a um conjunto de locais a proteger prioritariamente, ii) minimizar aárea total ardida, iii) minimizar o número de novas ignições e iv) minimizara parte do perímetro do fogo não protegida por recursos.

Sessão TB3: Scheduling in Industry *6 de Setembro, Quinta-feira, 11:30 - 13:20Sala: 23.3.9

Moderadora: Ana Moura

Automobile Repair Scheduling: a Real Case

Maria de Fátima Pilar, Eliana Costa e Silva, Ana Borges

Resumo. This work aims at answering a challenge proposed by a Por-

58 Sessão TB3: Scheduling in Industry *

tuguese company in the automobile repair sector, specifically the schedulingof repair interventions. A model of the problem is developed and a smallinstance defined from the data provided from the company is solved. Twocriteria, namely, minimization of tardiness of the repair orders and minimiza-tion of starting times of the interventions. The results show that, for bothcriteria, the predefined ordering of the intervention on each car are respected.Also the ordering sequencing of the intervention for each vehicle are ensuredand no overlapping of interventions and mechanics occurred.

Monte Carlo tree search for the flexible job shop with multipleprocess plans

Nicolau Santos, Gonçalo Figueira, João Pedro Pedroso

Resumo. Monte Carlo tree search is a general purpose search algorithmthat recently obtained remarkable results in the area of game play, with stateof the art performance in games such as Go, Chess and Shogi. The algorithmiteratively expands the most promising nodes of a tree, based on informationcollected from previous simulations, and orients the search, in order to bal-ance exploration and exploitation as the search progresses. In this work weapply Monte Carlo tree search to the Flexible Job Shop with Multiple ProcessPlans, a generalization of the classical Job Shop where operations of each jobare selected from a set of possible process plans. The proposed method isevaluated on instances derived from a real production system and on bench-marks from other related Job Shop problems. The quality of the proposedalgorithm is assessed through a comparison with results of other well-knownheuristics.

Modelo de programação inteira mista para um problema deescalonamento da produção da indústria cerâmica

Denise Ferreira, Carina Pimentel

Resumo. Nesta comunicação expõe-se um modelo de programação inteiramista, baseado num problema real de escalonamento de produção de artigosde loiça em porcelana, de elevada diversidade, de uma indústria cerâmica. Oproblema em questão concerne, mais concretamente, a um conjunto de pro-cessadores paralelos, flexíveis e não relacionados, de enchimento a alta pressãode moldes com pasta cerâmica líquida, do qual resultam lotes de dimensãovariável. As necessidades de produção de cada artigo chegam ao sistema numabase diária. Acrescentam-se ainda restrições associadas às propriedades dosartigos, elegibilidade de máquinas, total de setups diários, disponibilidade derecursos auxiliares discretos renováveis e não renováveis e do armazém local,bem como prazos de entrega. O objetivo passa por desenvolver um plano

Sessão TB3: Scheduling in Industry * 59

diário de agendamento da produção, que minimize o atraso total, decorrenteda diferença entre o período de conclusão e o de entrega. Surge, neste âmbito,o modelo matemático que considera todos os aspetos revelados no contextoreal e cujos resultados serão apresentados para um conjunto de instânciasgeradas a partir de dados recolhidos da empresa alvo do estudo.

Otimização de seleção de pessoas: estudo de caso numa linha demontagem de bicicletas

Helena Sofia Rodrigues, Arminda Pata

Resumo. No balanceamento de linhas de montagem ou desmontagem deprodutos a distribuição da carga de trabalho, geralmente é feita tendo emconta o número de tarefas, duração e precedências, bem como o número depostos de trabalho e o tempo inativo em cada estação de trabalho. O fatorde desempenho e a compensação da fadiga dos trabalhadores, também costu-mam ser estimados. No entanto, recorrentemente, a afetação das pessoas aospostos de trabalho, é feita sendo descurado o tempo de exposição aos riscos defadiga, sujeição inevitável decorrente da realização do próprio trabalho. Taldescuido pode incitar o desgaste físico e psicológico dos trabalhadores, e natu-ralmente, incrementar o absentismo laboral e comprometer o envelhecimentoativo da força de trabalho. Assim, construiu se um modelo matemático paraotimizar a afetação das pessoas aos postos de trabalho, levando-se em contafatores relacionados com a suposta fadiga, resultante do trabalho realizado emcada estação. Aptidões para desempenhar tarefas e tempos de exposição aosriscos físicos e psicológicos, são contemplados. Os resultados foram gerados noCPLEX, para uma linha de montagem de bicicletas, e visam contribuir parauma melhoria das condições de trabalho das pessoas, bem como proporcionarum aumento da qualidade de vida profissional.

Balanceamento e otimização de linhas de montagem

Ana Martins, Ana Moura

Resumo. Este projeto aborda o estudo de duas linhas de montagem deuma empresa. O desafio proposto foi solucionar um problema de capacidadeprodutiva de duas linhas de montagem. O objetivo principal foi minimizaro tempo de ocupação das linhas, não só através do seu balanceamento, mastambém o sequenciamento das tarefas e o próprio layout da linha, tendo emconsideração aspetos de ergonomia dos postos de trabalho. Primeiramentecomeçou-se por analisar o universo de produtos produzidos nas linhas emestudo, recolhendo todos os dados inerentes à sua produção, desde listas detarefas e respetivas precedências e tempos de execução das mesmas, criando-se

60 Sessão TB4: OR in Health and Life Sciences

vários cenários. Na criação destes cenários recorreu-se à utilização de algu-mas regras heurísticas para definir a ordem de afetação das tarefas e obterassim cenários teóricos que depois foram alvo de uma análise crítica para asua adaptação às condições reais de trabalho. Na elaboração destes balancea-mentos foram tidos em conta, entre outros, aspetos de ergonomia no posto detrabalho. Com este trabalho chegou-se a resultados interessantes, alguns dosquais foram objeto de implementação nas linhas em estudo. Contribuiu-separa a confirmação dos standards de trabalho e para o reforço da importânciada aplicação de princípios ergonómicos.

Sessão TB4: OR in Health and Life Sciences6 de Setembro, Quinta-feira, 11:30 - 13:20Sala: 23.3.10

Moderador: João Luís Miranda

Health workforce needs in Portugal

Diana F. Lopes, Jorge A. Simões, Eduardo A. Castro

Resumo. Health professionals are the keystone of any health system, bydelivering health services to the population. Health workforce planning isparticularly important as it ensures a proper balance between the supply anddemand of these professionals and it plays a central role on the Health 2020policy. Although this issue has been present on the public health agenda formany years, it remains nowadays a major concern in several countries. Thissituation may affect not only the productivity and the overall socio-economicdevelopment, but the quality of the healthcare services delivered to patients.Within the scope of a national funded project (HEALTH 2040 - Future needsof human health resources in Portugal till 2040), this study exploits the use ofa socio-technical approach to forecast the health workforce needs in Portugal,i.e. physicians and nurses, by specialties and by quinquenium till 2040. Usingthis knowledge, it is possible to infer about the training needs of these healthprofessionals, both in the medium and long run. These results can be used asa starting point to test the impact of different governmental policies. Furtherresearch is still needed to geographically distribute the health professionals inorder to overcome regional inequities.

Sessão TB4: OR in Health and Life Sciences 61

Home Hospitalization Planning: a systematic review

Edgar Sanches Mascarenhas, Bernardo Almada-Lobo, MárioAmorim-Lopes

Resumo. Home Health Care (HHC) services have experienced a signif-icant growth, since they are less costly, have a positive effect on patient’squality of life, and are regarded as a safe and promising alternative to conven-tional hospitalization. The diversity of human resources delivering the care,the variety of patients’ pathologies and required medical treatments, and thenecessity to integrate the patient’s home within the care supply chain makeHHC planning a complex task. Available approaches focus only on singlesubproblems of HHC planning, which is not ideal to ensure an effective androbust HHC decision making. New state-of-art operations research methodsand quantitative analysis will be developed to tackle the integrated planningproblem. Furthermore, this project will be a valuable contribution for a moreefficient and equitable home care delivery, maximizing resource utilization andpatients service levels.

Reinforcement Learning for Robust Programming: anApplication in Kidney Exchange

Tiago Monteiro, João Pedro Pedroso, Xenia Klimentova, AnaViana

Resumo. Kidney Exchange Programs allow incompatible patient-donorpairs to have a transplant exchange with another pair. The problem, thatcan be represented by a graph - where nodes represent incompatible pairsand arcs compatibility between donor in one pair and patient in another - hassome data uncertainty commonly addressed in the literature in two differentways: expected utility and fall-back mechanisms. We propose an alternativeinteractive tool to support decision makers in the process of choosing a so-lution, showing the predicted performance in case one or more pairs becomeunavailable. We use Monte Carlo Tree Search (MCTS) to generate multi-ple solutions. The procedure consists of using one optimal solution assumingdata certainty as the root node. From there, we generate a tree of failurepossibilities, each of them corresponding to a different scenario. A solution isgenerated for each particular scenario. At the end, each solution is evaluatedin all scenarios. We consider all scenarios for each cardinality of failing ver-tices, and average results for each solution in the set of scenarios associatedto a given number of failures. Finally, Pareto dominated solutions are filteredand the non-dominated average solutions are displayed and compared withthe worst case scenario.

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The demand for healthcare services and resources: patterns,trends and challenges in healthcare delivery

Sofia Cruz-Gomes, Mário Amorim-Lopes, Bernardo Almada-Lobo

Resumo. Together with the significant improvement in health and longe-vity came a number of health and economic concerns related to the demandfor healthcare services and resources: changes in the patterns of health andillness, increasing amount and complexity of healthcare services demanded,rising health expenditures and uncertainty about whether there will be enoughhuman, physical and financial resources to deliver the healthcare servicesneeded. This paper aims to draw attention to the importance of planningthe demand for healthcare in the aforementioned context, to create awarenessof the need for a comprehensive study on the demand for healthcare servicesand resources and to propose an integrated approach for planning them, toinform managers and policy-makers on what can be the main challenges onassuring healthcare delivery in the future.

A Glance on New European S&T Challenges: The COST Action“Medicines Shortages” (CA15105) in Portugal

João Luís Miranda

Resumo. Typical OR/MS methodologies and OR-related tools, e.g., An-alytics, Big Data, Biomathematics, High Performance Computing, Modeling-Simulation-Optimization, are being incorporated with COST (European Co-operation for S&T) networking activities to further promote competitivenessand sustainability. A convenient glance on OR/MS-based topics within thelarge landscape of international activities is presented, namely, recent cases inPortugal addressing Short Term Scientific Missions (e.g., “Patients and Sup-ply Chains Stakeholders Perspectives on Medicines Shortages”) and TrainingSchools (e.g., “Pharmaceutical Supply Chains: Medicines Shortages”) withinthe COST Action “Medicines Shortages” (CA15105) are revisited. Beyondthe S&T networks, Higher Education is also under analysis, being its effec-tiveness and performance appreciated upon the impact on graduates’ employ-ability too. In this way, well prepared academicians and young researchersare needed, their education and training requires special care, being the inter-connections discussed and future developments outlined.

Sessão TB5: Multiobjective Optimization I * 63

Sessão TB5: Multiobjective Optimization I *6 de Setembro, Quinta-feira, 11:30 - 13:20Sala: 23.3.14

Moderador: Carlos Henggeler Antunes

Optimização Angular no Planeamento de Tratamentos deRadioterapia: a importância da escolha da função objectivo naexploração do espaço de soluções

Humberto Rocha, Joana Dias, Tiago Ventura, Brigida Ferreira,Maria do Carmo Lopes

Resumo. IMRT (Intensity Modulated Radiation Therapy) é um tipode tratamento de radioterapia que usa um colimador multi-folhas por formaa conseguir controlar a radiação a partir de qualquer ângulo de irradiação.Cada feixe de radiação passa a ser interpretado como sendo constituído porum conjunto de subfeixes, cada um com uma determinada intensidade e queirradia durante um determinado período de tempo. A intensidade óptimade cada subfeixe é determinada através de um problema de optimização defluências (Fluence Map Optimization–FMO). O objectivo de um tratamentode IMRT é o de irradicar células tumorais, perservando o mais possível ascélulas saudáveis e mantendo a funcionalidade de todos os orgãos.

A selecção das direcções de irradiação (optimização angular) é um dos pas-sos essenciais no planeamento deste tipo de tratamentos, sendo um problemaaltamente complexo. Na optimização angular é normalmente consideradacomo função objectivo a função que deriva do problema FMO subsequente.Neste trabalho consideramos uma nova medida para guiar a descoberta dasmelhores incidências de radiação, integrado numa estrutura de optimizaçãoparalela não baseada em derivadas. Apresentam-se resultados para 10 casosclínicos de tumores da nasofaringe.

Modelação biobjetivo para renovação de infraestruturasmulticomponente

Nuno Sousa, Luís Alçada-Almeida, João Coutinho-Rodrigues

Resumo. Quando limitadas por restrições financeiras, a manutenção desistemas de infraesturturas leva frequentemente ao problema de decidir se oselementos desse sistema devem ser reparados completamente, i.e. restaurados

64 Sessão TB5: Multiobjective Optimization I *

ao seu estado ótimo, ou se uma reparação parcial, mais barata, é suficientepara o caso em questão.

A presente pesquisa apresenta um modelo biobjetivo para o planeamentoda manutenção a longo prazo dos sistemas de infraestruturas, que otimizaa escolha entre reparações: parciais, completas ou nenhuma ação a tomar.Os objetivos são a minimização do custo de reparação e maximização dosbenefícios aos utilizadores, medidos em função do nível de serviço de cadaelemento do sistema e privilegiando soluções que tornem sistemas parcial oucompletamente operacionais em todos os seus elementos. O modelo toma emconsideração a importância de cada sistema, descontos por atacado e conti-guidade dos sistemas, caso este tenham dimensão espacial.

O modelo foi testado num caso de estudo 23 passeios (sistemas), cada qualcomposto de 6 elementos, e comparado com duas políticas de reparação maissimples, de permitir apenas reparações parciais ou completas. Os resultadosmostram que os ganhos de eficiência por se implementar a política mista sãomuito significativos na região de orçamento médio-baixo.

Improving inventory management in an automotive supply chain:a multi–objective optimization approach using a genetic algorithm

João N.C. Gonçalves, M. Sameiro Carvalho, Lino Costa

Resumo. Inventory management represents a cornerstone inherent toany supply chain, regardless of industry type. Nevertheless, uncertainty phe-nomena related to demand and supply can induce overstock or even inventorystock-outs occurrences which, in turn, jeopardize one of the major principles ofsupply chain management: deliver the right product at the right place, at theright time and the right cost. This situation may also be aggravated in auto-motive supply chains, due to its complexity in terms of entities involved. Thisresearch paper explores a multi–objective optimization model and applies itto a real industrial company, purposing to address an inventory managementproblem. Moreover, a genetic algorithm is used to determine non–dominatedsolutions of an order size and safety factor system, and the obtained results arecompared to the current strategy adopted by the company. At this point, theadvantages and drawbacks of the model implementation are assessed. Basedon a set of logistic performance indicators, it is showed that the adoption of asmaller order size is potentially beneficial to the overall levels of inventory andvalue of inventory on–hand, without compromising service level. Assertively,the proposed model reveals to be an useful tool to practitioners involved inautomotive supply chains.

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Um método multi-objetivo de pesquisa em árvore Monte-Carlopara problemas de gestão florestal com restrições ambientais

Teresa Neto, Miguel Constantino, Isabel Martins, João PedroPedroso

Resumo. Desde que as preocupações ambientais se tornaram importantespara a sociedade, a gestão florestal para a produção de madeira tem vindo aconsiderar cada vez mais preocupações sobre a erosão do solo, a qualidade daágua, a preservação da vida selvagem, entre outras.

O lucro resultante da madeira cortada e as preocupações ambientais sãoobjetivos em geral de natureza conflituosa. Este trabalho apresenta um mé-todo bi-objetivo de pesquisa em árvore baseado no método de Monte-Carlopara problemas de optimização de gestão florestal com restrições na área dasclareiras, na área total e na área interior total de certos habitats. A cone-tividade entre estes habitats foi incorporada como o objectivo de naturezaambiental.

Foram usadas dezasseis instâncias de teste, reais e hipotéticas, com umnúmero de unidades de gestão de várias dezenas a mais de mil, e horizontestemporais entre três e nove períodos. Dado o carácter estocástico do mé-todo, este foi executado doze vezes para cada instância, obtendo-se em cadaexecução um número diferente de soluções eficientes. Em geral, o métodoencontrou em tempo razoável várias soluções eficientes para as instâncias mé-dias/grandes.


Sessão Plenária 26 de Setembro, Quinta-feira, 15:00 - 16:00Sala: 23.1.6

Moderador: Luís C. Dias

Boosting the Practice of Prescriptive Analytics

Bernardo Almada-Lobo FEUP, Porto, Portugal

Resumo. Most organizations already use effectively descriptive analyticsto understand past events. Fewer attempts are observed in the domain ofpredictive analytics to anticipate scenarios and estimate, and only a minor-ity of the firms leverages intelligent recommendations based on prescriptiveanalytics. The necessary change of the mindset of companies regarding theuse of optimization models and business decision support systems, requiresmore than just appropriate technology, people and processes. It demands aproper change management. In this talk, we make use of a few successful andunsuccessful business analytics projects, as well as recent developments inprescriptive analytics, to draw some guidelines and best practices to addressthis challenge.

Sessão TC1: Decision Support Systems * 67

Sessão TC1: Decision Support Systems *6 de Setembro, Quinta-feira, 16:00 - 17:30Sala: 23.3.4

Moderadora: Ana Raquel Xambre

Otimização do processo de tomada de decisão para o planea-mento de compras

Leandra Pinho, Ana Moura

Resumo. Numa organização onde não há custos de produção porqueo produto comercializado é comprado, a única maneira de reduzir custos éminimizando custos de transporte e armazenamento. A empresa em estudoé responsável pelo armazenamento e distribuição de produtos líquidos. Otransporte do produto é feito por via marítima para o porto de Aveiro. Oprincipal objetivo é ter um sistema automático que apoie a tomada de decisãona determinação das melhores datas para receção do produto e quantidadesa encomendar, de acordo com as previsões de venda. Para determinaçãodas quantidades a encomendar e as datas de receção dos navios, têm de serconsideradas diversas restrições, umas associadas ao transporte marítimo (ca-pacidade, dimensões, condições climatéricas, acesso ao porto, etc. . . ), e outrasaos clientes, capacidades dos tanques de armazenamento, stocks, contratos,preços produto, etc.. A maioria das restrições sofrem alterações diárias quetêm de ser consideradas aquando a tomada de decisão. A aplicação foi tes-tada com dados reais da empresa e as soluções obtidas comparadas com umhistórico dos planos de compra já desenvolvidos. Conclui-se que o sistemadesenvolvido não só ajuda a tomada de decisão no “imediato”, como tambémobtém soluções melhores do que as atualmente.

Scheduling optimization for an animal-feed company

Eduardo Curcio, Ana Sofia Figueiredo, Pedro Amorim, AntônioCarlos Moretti

Resumo. The objective of this work is the development of a decisionsupport system (DSS) for the production scheduling of an animal-feed com-pany. Important aspects of this industry are sequence-dependent and non-triangular setups. A mathematical formulation is firstly presented, whichincorporates the setup characteristics as well as other specific characteristicsof the company’s production system. Given the NP-hardness of the problem,

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a random-key genetic algorithm (BRKGA) is developed to compose the DSS.The main objective of the DSS is to provide scheduling solutions that mini-mize the makespan along with the total cleaning setups. Initial results showthat the DSS was able to reduce up to 40% the number of cleanings.

Optimizing customer response to direct marketing initiatives

Francisco Amorim, Bruno Batista, Paulo Pereira, PedroCampelo, Pedro Amorim, Vera Miguéis

Resumo. Players in retail, telecommunications and banking sectors quar-rel for retention and development of their customer base in highly competitivemarkets, fact that steered companies towards targeting customer experiences.Direct marketing has been proven to increase customer’s engagement andprolong loyalty, leading to higher customer equity over mass-marketing ap-proaches. Despite the attention given by researchers to predicting individual’sresponse to direct marketing initiatives and to the optimization of campaigns’specific goals, they have been treated as solo acts. We propose a methodologythat mitigates this gap. Firstly, state-of-the-art predictive techniques are ap-plied and benchmarked to model customers’ response to direct solicitations.The output of this first phase is then fed to a second stage prescriptive toolcombining simulation and heuristic techniques that, given capacity limitationsand other business rules, maximizes the overall campaign response over a re-stricted number of solicitations. The effectiveness of this Decision SupportSystem is tested on a real-life case study through an end-to-end process on acompany performing an upsell telemarketing campaign. The field experimentis expected to yield higher response and sales rates for the test group, whilelimiting the number of calls addressing the same client and keeping operatoridle time at a base level.

Specification of a decision support system for layout design in acomplex manufacturing environment

Ana Raquel Xambre

Resumo. Traditionally production systems that require flexibility andthe possibility to produce small batches of a large diversity of products, wereorganized into functional departments where equipment of the same type aregrouped together and parts are moved between departments. Although veryflexible, this type of system is very inefficient since as much as 95% of the timea product spends in the system is used for non-value added operations such astransportation and waiting. In this context Cellular Manufacturing Systems(CMS) have emerged as a viable alternative but there are past studies thatshown that when the diversity of products is considerable, functional layouts

Sessão TC2: Simulation and Optimization * 69

are better. Additionally, new ways of organizing resources have been proposedas a middle ground between CMS and functional layouts (e.g. virtual cellsor distributed layouts). These are seen as more flexible than CMS but moreefficient than functional layouts. There are various alternatives for arrangingresources in a plant dedicated to the production of small quantities of a largeset of parts. The goal of this work is thus to present the specification of aDecision Support System (DSS) to help decision-makers evaluate and comparealternative configurations for the layout of their manufacturing system.

Sessão TC2: Simulation and Optimization *6 de Setembro, Quinta-feira, 16:00 - 17:30Sala: 23.3.5

Moderadora: Maria Isabel Gomes

Simulating Airline Daily Operations: Schedule Recovery andAirline Behavior

David Antunes, Vikrant Vaze, António Antunes

Resumo. We present a simulation framework able to simulate the dailyoperation of an airline. Its intended use is to serve testbed for evaluatingthe performance of different types of airline schedules and operational strate-gies. It was designed having in mind the usability and data input needs.We demonstrate that an agent-based approach is an adequated way to modela complex system as an airline. In the case study, we focus on the recov-ery problem and show there are tradeoffs that are hard to gauge without asimulation model to compare them. Further, we show that an adequate rep-resentation of an airline’s operation needs include the correct representationof the airline’s agency, i.e. the decision it takes in face of uncertainty. Thisframework allows us to benchmark several scheduling and recovery solutionswhich would be hard to test without a simulation model needing to resort toactual implementation in reality and retrieve the data from there.

Combining Optimization-Simulation to Increase CheckoutEfficiency

Diogo Miranda, Ricardo Cunha, José Queiroga, Teresa Bianchi-Aguiar, Bernardo Almada-Lobo, José Luís Borges

Resumo. Retailers are often challenged with the problem of defining theideal number of store’s checkouts to fulfill customers’ demand and expected

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service level. The dilemma acquires an increasing importance considering thewide range of checkout solutions available nowadays and the high fluctuationof arrival rates across the day, week and year. Motivated by the case of afood retailer, we propose a two-fold methodology based on optimization andsimulation to tackle this problem. The first stage consists on the definition ofthe ideal configuration for each store by using queueing models to representthe expected impact of each checkout configuration, while the latter tests itsrobustness and appropriateness by simulating the store’s operation through-out an entire year. The performance assessment includes a sensitivity analysisto evaluate the trade-off between service level and associated costs, as well asrobustness tests that evaluate its suitability to changes in the arrival rate. Byapplying this methodology, it is expected a reduction of the retailer’s equip-ment costs and an increase of checkout utilization without compromising theservice level.

Uncertainty Analysis in Environmental Life Cycle Assessment -A Case Study Comparing Two Pulp Bleaching Options

Andreia Santos, Ana Barbosa-Póvoa, Ana Carvalho

Resumo. Life Cycle Assessment (LCA) is the most applied methodologyto assess environmental impacts associated with product’s life cycle. It con-sists on gathering an inventory of all the inputs and outputs of a product’s lifecycle and converting these into environmental impacts using characterizationfactors. Most uncertainty studies regarding LCA focus on the inventory gath-ering part and the uncertainty associated with the characterization factorshas been little studied so far. The main goal of the present work is to identifyhow this uncertainty should be analyzed and at which degree it may affectthe results of an environmental impacts’ study. To do so a detailed LCA isapplied to a case study. SimaPro is used to gather the inventory associatedwith the case study and ReCipe 2008 is the LCA method chosen to calculatethe environmental impacts. Through @Risk a Monte Carlo Simulation is de-veloped to assess the influence of uncertain parameters in the environmentalassessment output. Two different pulp bleaching processes are compared – El-emental Chlorine Free and Total Chlorine Free. The environmental impactsassociated with each bleaching process are compared and the influence of thecharacterization factors established.

Simulação do fluxo de pacientes num serviço hospitalar deRadiologia

Mafalda Neiva, Maria Isabel Gomes

Resumo. Em 2016 as despesas correntes em cuidados de saúde represen-

Sessão TC3: Supply Chain and Production Management II 71

tavam 8,9% do PIB nacional. Estudos detalhados da eficiência dos sistemashospitalares são essenciais para que seja possível uma redução dos custos semcomprometer a qualidade dos serviços prestados. Um serviço que carece deum estudo do seu desempenho é a Radiologia de um hospital do Centro Hospi-talar Lisboa Central, em particular no que se refere aos exames de tomografiacomputorizada. A logística associada a este exame é muito complexa, poistem que dar resposta a pedidos de exames efetuados por pacientes de diferen-tes de diferentes origens (internados, externos, da urgência e “via verde”) egraus de urgência. Neste trabalho modela-se e estuda-se o fluxo dos pacientesdeste serviço de Radiologia com o objectivo de se caracterizarem os diversospercursos existentes. Pretende-se identificar e analisar os principais obstácu-los que conduzem a algumas das ineficiências observadas. A modelação seráefectuada recorrendo à simulação discreta utilizando a ferramenta FlexsimHealthcare. Algumas sugestões de melhoria serão efectuadas ao responsáveldeste serviço de Radiologia.

Sessão TC3: Supply Chain and ProductionManagement II6 de Setembro, Quinta-feira, 16:00 - 17:30Sala: 23.3.9

Moderador: Cláudio Alves

Towards an Integrated Framework for Aerospace Supply ChainSustainability

Cátia Barbosa, Nuno Falcão e Cunha, Carlos Malarranha,Telmo Pinto, Ana Carvalho, Pedro Amorim, M. Sameiro Car-valho, Américo Azevedo, Susana Relvas, Tânia Pinto-Varela, AnaCristina Barros, Filipe Alvelos, Cláudio Alves, Jorge Pinho deSousa, Bernardo Almada-Lobo, José Manuel Valério de Carvalho,Ana Barbosa-Póvoa

Resumo. Supply chains have become one of the most important strate-gic themes in the aerospace industry in recent years as globalization and deeptechnological changes have altered the industry at many levels, creating newdynamics and strategies. In this setting, sustainability at the supply chainlevel is an emerging research topic, whose contributions aim to support busi-nesses into the future. To do so the development of new products and the

72 Sessão TC3: Supply Chain and Production Management II

response to new industry requirements, while incorporating new materials ap-pears as a path to follow, which require more resilient and agile supply chains,while guaranteeing their sustainability. Such supply chains will be better pre-pared for the future complex challenges and risks faced by the aerospacecompanies. Such challenges are addressed in this work, where an integratedframework is proposed to contribute to the resilience and sustainability ofaerospace supply chains. Using different analysis methods, the frameworkaddresses four important challenges in the context of aerospace supply chainsustainability: evolution and new trends, performance assessment, supplierselection, and supply chain design and planning.

On the integration of renewal projects with capacity planning

Luís Guimarães, Manuel Díaz-Madroñero, Bernardo Almada-Lobo

Resumo. In some manufacturing environments productive assets degradeover time leading to increasing costs or capacity loss. As such, these assetsare subject to frequent renewal operations to ensure their performance. Theserenewal periods often constitute a window of opportunity to adjust capacity.Under these circumstances, capacity planning must be jointly tackled withproduction and maintenance decisions to account for the costs, the unavail-able periods and to correctly define the new production capacity. However,traditionally these problems have been addressed separately both in the sci-entific community and in practice. In this talk we will show by means ofmathematical programming how the integration of the aforementioned pro-cesses can be performed, and the respective benefits, building on a real-wordcase from a two-stage process industry.

A hybrid optimization-simulation solution for the planning andscheduling of automated assembly lines

Miguel Vieira, Samuel Moniz, Tânia Pinto-Varela, Ana Barbosa-Póvoa

Resumo. The increasing automation in current manufacturing plantshas endured complex decision-support challenges into industrial planning andscheduling optimization strategies. With the modeling of production systemsgrowing in combinatorial complexity, the development of novel methodologiesto explore the nonlinear and stochastic behavior of scenarios that mimics realoperations are gathering significant relevance to holistically asses process man-agement decisions. With the computational advances, several authors haveexplored the advantages of combining simulation and optimization method-ologies in the evaluation of industrial planning and scheduling problems. The

Sessão TC4: Logistics and Transportation 73

hybridization approach enables a solution iteration between an upper level op-timization plan which feasibility is tested with a detailed discrete-event simu-lation of the process. With a proposed simulation-optimization methodology,this work explores the planning and scheduling solution for the managementof an industrial automated assembly systems in order to provide a real-timecapacity-feasible production workstation schedule. The results discuss the ad-vantages of this hybrid methodology to control systems dynamics and improveoverall process performance metrics towards the production optimization ofadvanced manufacturing systems.

A computational study on metaheuristic approaches for theintegrated planning and scheduling problem

Mário Leite, Cláudio Alves, Telmo Pinto

Resumo. In this presentation, we address the Integrated Planning andScheduling Problem (IPSP) on parallel and identical machines. Planning andscheduling are two of the main processes in the supply chain of companies.Although they have the same purpose, they are usually analyzed separately.The integration of different optimization problems that are related to dif-ferent levels of the organization may provide more efficient procedures andthus achieve global optimal solutions. In the IPSP, the planning componentdetermines in which periods of time the jobs will be processed taking intoaccount their release and due dates. On the other hand, the scheduling partdefines the machines where the jobs will be processed and their order withinthe periods. We propose a set of optimization approaches through heuristicand metaheuristic methods based on local search. More precisely, differentvariants of the variable neighborhood search algorithms were implemented.Several and innovative neighborhood structures for the IPSP were also pro-posed. We report on extensive computational experiments using a large setof instances from the literature. The obtained results show the efficiency ofthe proposed approaches, improving previously reported achievements in theliterature.

Sessão TC4: Logistics and Transportation6 de Setembro, Quinta-feira, 16:00 - 17:30Sala: 23.3.10

Moderadora: Inês Marques

74 Sessão TC4: Logistics and Transportation

A new optimization model for airline network design

André Gomes, António Antunes

Resumo. The strategic planning of an airline includes decisions on net-work design (including hub location) and fleet planning. The network of anairline, i.e. the routes, frequencies and capacities it operates, is a reflection ofits identity and strategy.

In this presentation, we propose an optimization model with a novel for-mulation for strategic network design of airlines with the goal of maximizingprofit. We consider the airline’s hubs (bases) and fleet to be given. Themodel accounts for leg-based demand, operating costs and benefits to deter-mine which routes to fly and respective frequencies, with a preliminary fleetassignment completing the solution. We discuss possible extensions to themodel formulation for taking into account demand uncertainty, alliance/code-share agreements and competition effects. Preliminary computational resultsindicate that our formulation is more efficient than previous ones.

Model results supply information on which routes an airline should open,reinforce, downgrade or close, and whether destinations should be served non-stop or through connecting flights, independently or in collaboration withpartner airlines. Additionally, they provide information on how the airline’snetwork should be redesigned to take advantage of new generation aircraft, aswell as to deal with possible changes in demand, notably those due to marketcompetition.

A large neighborhood search heuristic for solving the airport slotallocation problem

Nuno Antunes Ribeiro, Alexandre Jacquillat, António Antunes,Amedeo Odoni

Resumo. Most of the busiest airports outside the United States, includ-ing the major connecting hubs, are classified as Level 3. At these airports,airlines need to be assigned slots by a coordinator to schedule flights. Theunderlying slot allocation process is very complex, with multiple criteria, rulesand priorities, which are specified into the IATA guidelines. Recently, someoptimization models have emerged in the literature aiming to support slot co-ordinators to better accommodate airlines’ preferences at these airports. How-ever, these models are not yet compliant with the IATA guidelines, and theirapplication to large-size airports is very limited. In this research we extendprevious work in two major ways. First, we propose a novel integer program-ming model that optimizes slot allocation decisions at schedule-coordinatedairports, while fully complying with the rules specified by the IATA guidelines.

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Second, we develop a heuristic algorithm based on large scale neighborhoodsearch methods to solve the slot allocation problem at large-size airports. Weapplied our model and heuristic at three Portuguese airports, Madeira (FNC),Porto (OPO) and Lisbon (LIS). Results suggest that our approach can signif-icantly improve the efficiency of current practice by providing slot allocationresults that match better the slot requests of airlines.

Modelação multiobjetivo em projetos de renovação de sistemasferroviários

Nuno Sousa, Luís Alçada-Almeida, João Coutinho-Rodrigues

Resumo. O modo de transporte ferroviário é visto como um modo detransporte promissor dos pontos de vista económico, energético e ambiental.No entanto, a ferrovia necessita atualmente de intervenções de fundo, frutode falta de investimento nestas infraestruturas nas últimas décadas.

Neste sentido, a presente pesquisa apresenta um modelo multiobjetivo parao planeamento de renovações na infraestrutura ferroviária, atendendo a trêsobjetivos: distribuição equitativa do investimento pelos anos de projeto, min-imização do custo total e minimização dos adiamentos de obras prioritárias.O modelo está sujeito a restrições operacionais, que visam limitar os atrasoscausados à circulação, e aplica-se a intervenções de fundo (renovações) quenão requeiram fecho completo de linhas e reencaminhamento de circulaçõesdurante o tempo de obras.

O modelo é aplicado a um caso de estudo envolvendo um problema realde gestão de ativos, para o qual são gerados e analisados vários cronogramasde Gantt de soluções não-dominadas. Os resultados mostram que existe umconsiderável “trade-off” entre os objetivos de distribuição equitativa do inves-timento e adiamentos de obras prioritárias, mas que o custo total é, para estecaso de estudo, praticamente constante.

The ambulance dispatching and relocation problems: optimiza-tion approaches using a time-preparedness metric

Ana Sofia Carvalho, Maria Eugénia Captivo, Inês Marques

Resumo. In the Emergency Medical Service (EMS) context, the decision-making process plays a very important role. Three levels of decision can beidentified: strategic, tactical and operational. This work focus on the oper-ational level by solving the dispatching and relocation ambulance problems.Ambulance dispatching decisions assign ambulances to emergencies and therelocation problem decides to which base (re)assign available ambulances.An effective and efficient EMS response is needed, so it is essential to have

76 Sessão TC5: Multicriteria Decision Making - Methodology *

an optimized system. We propose integrated optimization approaches forthe dispatching and relocation ambulance problems through a mathematicalmodel and a pilot-method heuristic. A preparedness metric is used to evalu-ate system’s coverage. The goal is to help managers in the decision-makingprocess at the operational level tasks, providing an improved service qualitythat is of interest to anyone. Some experiments are performed to validate theeffectiveness and efficiency of the proposed approaches using EMS data fromLisbon, Portugal, where solving these problems has been a handmade task.

Sessão TC5: Multicriteria Decision Making -Methodology *6 de Setembro, Quinta-feira, 16:00 - 17:30Sala: 23.3.14

Moderadora: Mónica Oliveira

On the Choquet multiple criteria preference aggregation model:Theoretical and practical insights from a real-world application

José Rui Figueira, Marta Bottero, Valentina Ferretti, SalvatoreGreco, Bernard Roy

Resumo. We consider the use of the Choquet integral for evaluatingprojects or actions in a real-world application starting from the case of there-qualication of an abandoned quarry. Despite the Choquet integral beinga very well-known preference model for which there is a rich and well devel-oped theory, its application in a multiple criteria decision aiding perspectiverequires some specific methodological developments. This led us to work outand implement, in practice, two new procedures: A first procedure to buildinterval scales with the objective of assigning utility values on a common scaleto the criteria performances, and a second one to construct a ratio scale forassigning numerical values to the capacities of the Choquet integral. Thisarticle discusses the strengths and weaknesses of the Choquet integral as ap-pearing in the case study, proposing as well insights related to the interactionof the experts within a focus group.

Sessão TC5: Multicriteria Decision Making - Methodology * 77

A new ranking for the PyeongChang 2018 Winter OlympicGames Based on Copeland Method

Nissia Bergiante, João Carlos Soares de Mello

Resumo. In this paper we propose the use of ordinal multicriteria meth-ods to study the results of the PyeongChang 2018 Winter Olympic Games.The analysis is based on Copeland method an it can be called HierarchyCopeland method. Our aim is to establish a final ranking that take into ac-count three different approaches to rankcountries: the Lexicographic method,the total number of medals and the difference between all modalities of theOlympic Games. As a result we have obtained a final ranking that can beused to analyze investment strategies in sports to maximize returns and typesof medals won by the countries.

Geração de funções de utilidade em Análise de AceitabilidadeMulticritério Estocástica (SMAA)

Luís C. Dias, Rudolf Vetschera

Resumo. A Análise de Aceitabilidade Multicritério Estocástica (Stochas-tic Multicriteria Acceptability Analysis - SMAA) é uma abordagem de avali-ação multicritério aplicável quando os valores de alguns parâmetros estão emfalta ou são incertos, o que é comum em aplicações na área do ambiente, daenergia, e outras. Os métodos SMAA baseiam-se em simulação Monte-Carlo,gerando aleatoriamente esses valores, para obter alguns indicadores de síntesepara informar os decisores. A literatura tem-se debruçado sobre a forma degerar aleatoriamente o desempenho das alternativas e os pesos dos critérios,mas não tanto sobre a geração de funções de utilidade ou de valor. Neste tra-balho discutimos algumas formas de gerar funções de utilidade, considerandoou não restrições sobre a sua forma. São revistas algumas abordagens exis-tentes e propostas novas abordagens, discutindo as propriedades que um bommétodo deveria apresentar. Apresentamos de seguida um estudo computa-cional que compara diferentes formas de gerar utilidades aleatórias em relaçãoàs propriedades discutidas.

Multi-Criteria Decision Analysis for Health TechnologyAssessment: Which agenda to address methodological challenges?

Mónica Oliveira, Inês Mataloto

Resumo. Multi-criteria decision analysis (MCDA) concepts, models andtools have been increasingly used within Health Technology Assessment(HTA),with several studies pointing out practical and theoretical issues related to its

78 Sessão TC6: Technology Management and Policy

use. This study departs from an overview of MCDA in HTA literature toreflect upon a methodological agenda to advance the area. A systematic re-view was conducted to identify studies discussing, developing or reviewingthe use of MCDA for evaluating health technologies using aggregation ap-proaches, with 129 studies being analysed. The PROACTIVE-S approachwas built and used to analyse model applications’ methodological quality,showing poor compliance with good methodological practice regarding be-havioural analyses, discussion of model assumptions and uncertainties, mod-elling of value functions, and dealing with judgmental inconsistencies. Re-ported methodological-related limitations and challenges of reviewed studieswere digested, with top 5 challenges being related to evidence and data synthe-sis, value systems’ differences and participants’ selection issues, participants’difficulties, methodological complexity and resources balance, and criteria andattributes modelling. Following these analyses, this presentation will discusswhich research pathways have the potential to address the identified limita-tions and challenges, specifying the need for developing new model featuresand good practice guidelines, as well as technologies to enable participationand behavioural research.

Sessão TC6: Technology Management andPolicy6 de Setembro, Quinta-feira, 16:00 - 17:30Sala: 23.3.15

Moderador: João Claro

A Novel Optimization Model for Short Term Storage ofContainers in Empty Container Terminals

José Oliveira, Rui Oliveira, Marta Gomes, Vasco Reis, RosárioMacário

Resumo. Small scale empty container terminals are subject to severespace and operational constraints. The requirements of clients and port au-thority give rise to uncertainties relating to the dwell time of specific contain-ers. At present, the task of stacking the containers is assigned to the terminalmanagers who, relying on their own perceptions and devised mental processes,contrive as good as possible solutions to this problem. These solutions are ar-guably the best and lack the consistency that the shipping business requires.The optimization model presented relies in the programming of the heuristic

Sessão TC6: Technology Management and Policy 79

rules to which the container allocation abides, in an algorithm for the allo-cation of forklifts and storage positions, including a TSP solver. This modelallows for the selection and optimization of parameters, offering the possibil-ity of studying the performance of different stacking policies. The novelty ofthis solution stems from its capacity to accommodate dwell time uncertaintyas well its robustness dealing with several parametrized stacking policies andthe availability of different depot resources. A simulation model under devel-opment, providing a testing platform, which results will be shortly available,together with the validating experts opinion, shall prove a valuable tool inimproving the terminal operational costs and service level.

Adapting water tariffs to climate change - An impact assessment

Francisco Silva Pinto, Bruno de Carvalho, Rui Marques

Resumo. Utilities face challenges that will most likely deepen in thefuture, and if left unattended, they may incur relevant net damage costs de-fying our society and environment. An ever more frequent impact is resourcescarcity, where a water deficit can be brought upon due to an increasinglyuncertain climate, overexploitation and contamination of resources, and alsolack of infrastructure. Thus, in the water supply sector, the robustness andresilience of systems depends on ‘preparedness’ measures able to establish alink between resources availability, utility costs, water tariffs (or other sourcesof revenue) and demand. A multi-objective optimization model is built to dealwith those diversified requirements. The model is solved through achievementscalarizing functions with several weighting coefficients for a reference point,so as to provide a significant perception of possible revenue options (and theirimpact) to the decision makers. There is a focus on the role of tariffs, andits social, economic and environmental impacts are assessed related to costs,demand, and water resources availability. The São Paulo metropolitan area(Brazil) case-study is assessed, particularly the Cantareira reservoir system.Those solutions allow tariffs to avoid unnecessary constraints on utilities andcustomers, as well as on the remaining stakeholders.

Wildfire risk governance - From a simple issue to a complex riskproblem

Tiago M. Oliveira, João Claro, Patrícia L. Costa, João Pinho,Abílio P. Pacheco, José M.C. Pereira

Resumo. Throughout the 20th century several countries evolved theirpolicies, regulations, organizations and operational systems to keep protect-ing populations and forests against wildfires. We examined the evolution of

80 Sessão TC6: Technology Management and Policy

wildfire risk governance during the last 100 years in Portugal, the countrywith highest fire incidence in Europe, based on content analysis of officialregulations. We adopted an analytical socio-ecological framework to describethe system’s adaptive capacity and built a chronology of its evolution. Wefound that most regulatory instruments were shaped in crisis contexts andthe system evolved differently according to the relative magnitude of socialand ecological changes, which ultimately drove problem framing and adoptedsolutions. Since the 80s, that framing misrepresented the dynamics of thesocio-ecological processes that fostered fuel accumulation and amplified socio-technological failures to explain fire occurrences. A simple risk problem man-aged with informal local solutions escalated to a complex ambiguity-riddenproblem. The formalization of the wildfire management system under theumbrella of civil protection set a paradigm shift that undermined forest pro-tection. We hypothesise that governance deficits hindered the emergence of acohesive system able to perform effectively, guaranteeing low fire risk exposurewhile ensuring professional and profitable management of forest resources,overwhelmingly managed by private owners.

Sequences of alignment between technologies and adopters: Caseresearch of a health screening implementation

José Coelho Rodrigues, Ana Cristina Barros, João Claro

Resumo. Although the study of implementations of technologies as pro-cesses of mutual adaptations or sequences of alignment has long been estab-lished, its extension to contexts with networks of organizations as a locusof adoption has only recently started to see some development. Misalign-ments between technologies and adopters, i.e., the lack of compatibility be-tween them that generates the need for alignment efforts, are a major causeof productivity losses in early stages of implementation projects. Alignmentmanagement is particularly challenging when the adopter, instead of a sin-gle organization, is a network of organizations, a setting that is becomingincreasingly important as a key organizational structure in many industries,such as healthcare. Findings from a multiple case research of the implementa-tions of a new health screening program in networks of healthcare providers inthe North of Portugal provide evidence about the emergence, utilization andconsequences of sequences of alignment, namely when and how non-linear se-quences are used by implementation managers, and what are the consequencesof such sequences of alignment. This work contributes to the body of knowl-edge of an important, yet understudied, topic in technology management, andprovides guidelines to help managers achieve higher levels of performance intechnology implementation projects.

Programa de 7 de Setembro 81

7 de Setembro (sexta-feira)

9:30 - 11:00

F1 (sala 23.3.4): DEA and Performance Analysis IIF2 (sala 23.3.5): Discrete Optimization and Graphs - Methodology *F3 (sala 23.3.9): Vehicle Routing *F4 (sala 23.3.10): Location and Distribution *F5 (sala 23.3.14): Energy *F6 (sala 23.3.15): Multiobjective Optimization II


11:30 - 12:30 Sessão Plenária 3 (sala 23.1.6): António Murta

12:30 - 13:20 Entrega de Prémios e Sessão de Encerramento (sala 23.1.6)

13:30 -14:45 Almoço


82 Sessão F1: DEA and Performance Analysis II

Sessão F1: DEA and Performance Analysis II7 de Setembro, Sexta-feira, 9:30 - 11:00Sala: 23.3.4

Moderadora: Ana Camanho

DEA efficiency in the public sector using provider and customeropinion: An application to the Spanish health system

Jesus Tapia, Bonifacio Salvador

Resumo. Measuring the relative efficiency of service-producing units(hospitals, state services, ...) is an important purpose of Data EnvelopmentAnalysis (DEA). In recent years, some efficiency analysis approaches haveused customer opinion as data when considering it a crucial measure of thequality of the received service. In this paper, we analyse the DEA efficiency ofthe services through satisfaction-opinion indexes of both customers (outputs)and providers (inputs); the provider (healthcare personnel, civil servants, ...)opinion indexes are considered as a measure of the quality of the offered ser-vice. When the opinion indexes are estimated from survey samplings of cus-tomers and providers, the technical efficiency score, obtained using the DEAclassic models, is an estimator of the populational efficiency obtained if a cus-tomer and provider census were possible. We use the bootstrap methodologyto study the properties of this estimator and propose results to determinethe sample size needed to achieve a fixed accuracy in the efficiency estima-tion with confidence interval. Using this methodology and opinion indexesobtained from two surveys, one of doctors of primary healthcare and one ofpatients, we analyse the efficiency in the Spanish health system.

PRICDEA: preference information incorporation for decision-making using the Choquet integral in a DEA model

Miguel Pereira, José Rui Figueira, Rui Marques

Resumo. In a world in permanent (r)evolution that revolves aroundmoney, seeking new ways to contain costs, better allocate resources, and, over-all, improve performance is a constant across all the fields. Hence, the usageof computational methods based on statistical science is crucial for achievingan appropriate combination of efficiency and effectiveness, especially in do-mains where the decision-making process is a complex task. This is where

Sessão F1: DEA and Performance Analysis II 83

Data Envelopment Analysis (DEA) comes in. However, as a non-parametricand, usually, purely objective technique, DEA makes up for in flexibility andadaptability what it lacks in incorporating preference information, which isparticularly important in areas where the judgment of decision-makers is cru-cial. This work proposes a cutting-edge and original approach to fill in thisknowledge gap by linking DEA and multi-criteria decision-making with an ad-ditive DEA model that takes into consideration criteria interactivity, by usingan inference methodology to determine their weights, and decision-makers’preference information incorporation, by applying the Choquet multi-criteriapreference aggregation model. Thus, PRICDEA (PReference information In-corporation using the Choquet integral in a DEA model) was born, yield-ing acceptable and valid results in a tailor-made case study of performanceassessment of Portuguese National Healthcare Service secondary healthcareproviders.

Using students’ university scores to benchmark secondary schools

Maria Silva, Ana Camanho

Resumo. Data on university students’ first year scores is used as a meansto compare and benchmark secondary schools on their ability to lead studentsto university success. Two universities in Portugal, Portuguese Catholic Uni-versity (with 7 faculties) and University of Porto (with 14 faculties) wereused to compute a number of metrics, based on which secondary schools werecompared. The performance of more than 10.000 students from 65 differentdegrees was explored for a three year period. There are mainly two researchquestions addressed in this paper: what are the determinants of success forfirst year university students? and what is the role of the secondary school oforigin in determining success for first year university students? These researchquestions were addressed through regression based models and DEA models.Conclusions from the preliminary analysis point to the importance of scoreson entry in explaining the success of students at the university. The typeof school appears as the second most important factor in determining stu-dent’s success, with public schools performing better than private. Aggregateschool’s performance based on their ability to prepare students for univer-sity success, tell a complete different story than ranking of schools based onnational exams.

Regulation and benchmarking: a formative evaluation ofPortuguese wastewater services using composite indicators

Alda Henriques, Ana Camanho, Pedro Amorim, Gabriel Silva

Resumo. The well-functioning of the water sector is fundamental for

84 Sessão F2: Discrete Optimization and Graphs - Methodology *

sustainable development. This study contributes to the improvement of thewastewater sector through the empowerment of regulators’ governance mod-els. We developed a framework for enhanced monitoring of the quality ofservice provided by water operators, focusing on wastewater treatment ac-tivities. Its application can be extended to other activities related to watersupply or other regulatory contexts. The framework is rooted on quantita-tive benchmarking and uses frontier techniques (Data Envelopment Analysis).The evaluation of operators’ performance is illustrated for a set of whole-sale and retail operators in the year 2014, with the indicators collected bythe Portuguese Water and Waste Services Regulatory Authority (ERSAR).It considers three dimensions of quality of service: protection of user inter-ests, operator sustainability and environmental sustainability. We developeda composite indicator, estimated using a directional distance function, whichincorporates weight restrictions to reflect alternative perspectives concerningthe emphasis given to each dimension. In a second-stage, a Tobit regressionwith bootstrapping was used to analyze the impact of contextual factors onoperators’ activity. This framework can be used to disseminate best practicesand motivate continuous improvement, contributing to increased transparencyand accountability in the water sector.

Sessão F2: Discrete Optimization and Graphs- Methodology *7 de Setembro, Sexta-feira, 9:30 - 11:00Sala: 23.3.5

Moderador: Jorge Orestes Cerdeira

New results on the order, average degree and degree sequenceof (sub)graphs

Sofia J. Pinheiro, Domingos Cardoso

Resumo. Considering some results of extremal graph theory, namely theMoore bound on the order of graphs with a particular diameter and averagedegree, and the Turan’s theorem which is associated to the very beginning ofextremal graph theory (stating an upper bound on the size of graphs withoutq-cliques), bounds on the order and average degree of subgraphs of a givengraph are established. Furthermore, the Erdos-Gallai theorem that gives anecessary and sufficient condition for a sequence of nonnegative integers begraphic, is extended to the case of graphs with positive edge weights.

Sessão F2: Discrete Optimization and Graphs - Methodology * 85

Diameter-constrained clique relaxations with fixed-length paths

Filipa Duarte de Carvalho

Resumo. A k-club is a subset of vertices of a graph that induces a sub-graph of diameter at most k. The k-club is a clique-relaxation model. Itrelaxes the clique requirement of minimum distance between every pair ofvertices. In spite of providing easy reachability for small values of k, k-clubsmay fail on other clique cluster features, namely the ability of keeping the di-ameter within a small range when one vertex is removed from the graph. Oneway of guaranteeing this important cluster property is to impose an additionalfixed-length-path constraint on a k-club. Alternatively, fixed-length-path k-clubs may be defined in terms of the diameter of the spanning trees containedin the graphs they induce. A compact integer linear formulation for the maxi-mum fixed-length-path k-club problem is developed. For the special case k=3,simplified formulations are presented and discussed. Computational resultsobtained on a set of randomly generated graphs are reported.

Solving the linear fractional assignment problem

Marta Pascoal

Resumo. The goal of the assignment problem is to find an assignmentthat minimizes a linear objective function. The linear fractional assignmentproblem is an extension of the latter, with the quotient of two linear functionsas the objective function. Such a problem can be transformed into a linearprogram, by means of a change of variables. However, this may not be inter-esting from a practical point of view given that doing so implies losing theassignment problem structure and properties. Traditionally linear fractionalassignment problems have been solved by parametric methods that solve asequence of assignment problems with varying arc costs. Nevertheless, opti-mal linear fractional assignments are also efficient assignments with respectto a bicriteria problem where one function is to minimize and the other is tomaximize. In this talk we use a weighted sum approach to solve the linearfractional assignment problem and compare the two methods empirically.

The combinatorial product sum problem

Paulo Bárcia, Jorge Orestes Cerdeira

Resumo. Let E 6= ∅ be a finite set, and suppose there are two weights,pe > 0 and se, associated to every element e ∈ E. If X ⊆ E, the weightof X is z(X) =

∏e∈X pe +

∑e∈X se. Call arbitrary {∅} 6= F ⊆ 2E the set

of feasible sets. The Combinatorial Prod/Sum Problem (CPSP) seeks for a

86 Sessão F3: Vehicle Routing *

minimum weight feasible set. We show that CPSP is NP-hard, even whenF = 2E ; give a procedure to obtain lower bounds on the optimal valuesthat consists of maximizing a piecewise concave function of a single variable;present an integer cut approach to obtain optimal solutions; and report somecomputational experiments for different sets of feasible sets including (s →t)-paths on acyclic directed graphs, and matchings and spanning trees onundirected graphs.

Sessão F3: Vehicle Routing *7 de Setembro, Sexta-feira, 9:30 - 11:00Sala: 23.3.9

Moderadora: Cristina Requejo

Dynamic approaches to solve the Smart Waste CollectionRouting Problem

Carolina Morais, Tânia Ramos, Ana Barbosa-Póvoa

Resumo. A Dynamic Inventory Routing Problem model embedded intoa Rolling Horizon solution approach is developed, along this paper, to solvethe Smart Waste Collection Routing Problem. This allows the definitionof dynamic waste collection routes that explore the use of real-time infor-mation on the bins’ fill-level, over a medium-term horizon. Opposite to apublished short-term approach, based on the solution of the Vehicle Rout-ing Problem with Profits that maximize daily profits, the presented approachleads to better results translated into higher operational profits. This evi-dence is shown through the solution and comparison of both the short-termand the medium-term approaches in a set of small instances where differentactive rolling horizon intervals are tested. A large instance obtained from areal waste collection system case study is also studied, and the results confirmthe conclusions obtained when solving smaller instances.

A robust Vehicle Routing Problem with Selective Backhaulsunder revenue uncertainty

Maria Santos, Pedro Amorim, Eduardo Curcio

Resumo. The Vehicle Routing Problems with Selective Backhauls(VRPSB) is a NP-hard optimization problem that aims to design efficient

Sessão F3: Vehicle Routing * 87

transportation plans so that a fleet of vehicles simultaneously deliver requeststo mandatory customers and optionally pickup materials from suppliers (back-hauls). Each backhaul has an associated revenue and the selection process isbased on the impact that revenue has on minimizing the total routing costs(total distance minus total revenue collected). Despite the suitability of theVRPSB to real-world problems, no study addressing its uncertain counter-part was yet carried in literature. Moreover, uncertainty in revenues is rarelyinvestigated in transportation planning problems. One trendy approach todeal with uncertainty in VRPs is robust optimization that, instead of usinga probability distribution function, represents uncertainty as a bounded set.In robust optimization the goal is to guarantee solution feasibility for all po-tential realizations of the uncertainty. The main objectives of this work are:i) to develop a model and solutions methods to deal with uncertain revenuesusing a robust optimization approach; ii) to provide the study of a problemnot yet covered in literature (Robust VRPSB); and iii) to gather insights onthe properties and robustness measures of the related robust plans.

Multiple vehicle synchronisation in a full truck-load pickup anddelivery problem: a case-study in the biomass supply chain

Ricardo Soares, Alexandra Marques, Pedro Amorim

Resumo. The search for efficiency and flexibility in transportation plan-ning processes for real life applications is rather challenging. The increasingaccess to sensor technologies and the advent of Industry 4.0 can highly con-tribute to supply chain efficiency, namely in transportation planning. In thiscontext, the synchronisation of vehicles performing different operations atgiven locations can potentiate further gains in logistics costs. In this work,the full truck-load pickup and delivery problem with multiple vehicle syn-chronisation is presented. This problem is motivated by a real-life applicationin the biomass supply chain “hot-system”, where it is necessary to simulta-neously perform chipping and transportation operations at the forest road-side. Its purpose consists in determining the integrated routes planning forthree distinct types of vehicles which need to perform interrelated operationswith minimum logistics costs. We extend existing studies in synchronisa-tion in vehicle routing problems by acknowledging multiple synchronisationaspects, and present a novel mixed integer programming model (MIP) andtransportation network to successfully model the problem. Furthermore, asolution method is developed for solving large-scale instances and is testedin a case-study of a biomass supplier in Finland, where significant gains inoverall logistics costs can be acknowledged.

88 Sessão F4: Location and Distribution *

The generalized Skill Vehicle Routing Problem: time windows,precedence constraints and device uncertainty

Paola Cappanera, Cristina Requejo, Maria Grazia Scutellà

Resumo. We study a generalization of the Skill VRP that incorporatesvery realistic temporal constraints, the management of special devices, anduncertainty aspects, making the problem particularly significant in applica-tion contexts such as Field Service and Home Care. We are given a directednetwork where nodes correspond to clients, a set of (partially ordered) oper-ations required by each client, a set of the available technicians, and a set ofoperations each technician is skilled to perform. An operation may also re-quire the use of a special device. Given technician dependent traveling costs,we study the problem of defining the tours for the technicians and for thespecial device, while respecting skill compatibility constraints among clientsand technicians, the partial ordering relation associated with operations ateach client, time window constraints at the clients, maximum workday du-ration of the technicians and synchronization. The objective function, to beminimized, is the overall traveling cost. Uncertainty on availability of thespecial device is addressed. We propose a mathematical model for the gener-alized Skill VRP, and a robust model for its uncertain counterpart. Resultsof preliminary computational experiments will be reported.

Sessão F4: Location and Distribution *7 de Setembro, Sexta-feira, 9:30 - 11:00Sala: 23.3.10

Moderador: Pedro Amorim

Dynamic Facility Location Problem under Uncertainty: anextension to stochastic setup times

Maria do Céu Marques, Joana Dias

Resumo. Dynamic facility location problems consider situations whereit is important to decide not only where but also when to open (or close)facilities, given a planning time horizon. The majority of models presented inthe literature considers binary decision variables that define whether facilitiesare open or not in a given time period. If a facility is first opened at period tthen clients can usually be assigned to it from t forward. However, in reality, todecide to open a facility at a given time period is quite different of having the

Sessão F4: Location and Distribution * 89

facility prepared such that clients can be assigned to it, exactly from that timeperiod forward. In this talk, we propose a new mathematical model whereuncertainty in the setup time of facilities is explicitly considered. This meansthat the Decision Maker is only capable of deciding where to locate facilitiesand when to begin all the necessary works to get the facilities operational, butthe real time elapsed until really opening each facility is not known for sure.We also present the primal-dual heuristic that was specifically developed forthis problem, and compare its performance with the performance of a generalsolver.

Problema de localização-distribuição com maximização deproveitos: uma aplicação na área do turismo

Rui Borges Lopes, Carlos Ferreira, Beatriz Sousa-Santos

Resumo. Nos problemas de localização-distribuição (PLD), onde se pro-cura resolver de forma integrada problemas de localização e problemas derotas de veículos, têm surgido diversas variantes e aplicações na literatura.Esta comunicação pretende focar-se numa aplicação específica que não foiainda abordada ao nível dos PLD. Nomeadamente, em viagens turísticas,qual a escolha do hotel onde permanecer e quais os pontos de interesse a visi-tar. Pretende-se maximizar o proveito resultante de visitar pontos de interesse(não sendo obrigatório visitar todos), sujeito a um conjunto de restrições (deorçamento, janelas temporais, duração máxima de rota, etc.) que o torna demuito difícil resolução. Será apresentada nesta comunicação uma formulaçãomatemática e uma aproximação heurística que permitem resolver algumasinstâncias deste PLD.

Planning the delivery of Home-Based Long-Term Care: Amathematical programming-based tool to support routes’ planning

Daniel Espadinha, Teresa Cardoso-Grilo

Resumo. The adequate planning of home-based long-term care (HBLTC)is essential in the current European setting where long-term care (LTC) de-mand is increasing rapidly, and where home-based care represents a poten-tial cost-saving alternative from traditional inpatient care. Particularly, thisplanning should involve proper route planning to ensure visits of health pro-fessionals to patients’ homes. Nevertheless, literature in the specific area ofHBLTC planning is still scarce. Accordingly, this paper proposes a tool basedon a mathematical programming model – the LTCroutes – for supportingthe daily planning of routes to visit LTC patients’ homes in National HealthService-based countries. The model allows exploring the impact of consider-ing different objectives relevant in this sector, including the minimization of

90 Sessão F5: Energy *

costs and the maximization of service level. Patients’ preferences, traffic con-ditions and budget constraints are also considered in the proposed model. Toillustrate the applicability of the model, a case study based on the NationalNetwork of LTC in Portugal is analyzed.

Consistent consolidation strategies in grocery retail distribution

Sara Martins, Pedro Amorim, Bernardo Almada-Lobo

Resumo. In the food retail sector, maintaining the food quality acrossthe supply chain is of vital importance. The quality of the products is depen-dent on its storage and transportation conditions and this peculiarity increasesthe supply chain complexity relatively to other types of retailers. Actually,in this industry there are three types of food supply chains: frozen, chilledand ambient. Moreover, food retailers run different store formats, of differentsizes, assortments and sales volume. In this study we research the trade-offbetween consolidating a range of products in order to perform direct deliver-ies to the stores versus performing separate delivery routes for products withdifferent transportation requirements. A new consistency dimension is pro-posed regarding the periodicity that a consolidation strategy is implemented.The aim of this paper is to define a consolidation strategy for the deliverymode planning that allows to smooth the complexity of grocery retail oper-ations. A three-step approach is proposed to tackle a real size problem in acase-study with a major Portuguese grocery retailer. By changing the con-solidation strategy with a complete consistent plan the company could reachannual savings of around 4%.

Sessão F5: Energy *7 de Setembro, Sexta-feira, 9:30 - 11:00Sala: 23.3.14

Moderador: Manuel Matos

Transmission expansion planning and cost allocation underuncertainty

Manuel Loureiro, João Claro, Paul Fischbeck

Resumo. European power systems are undergoing a unification process.As market coupling efforts advance, new interconnection expansions may berequired to address power transfer needs of Member States. Concurrently,

Sessão F5: Energy * 91

the energy mix is changing in favour of renewable energy sources, further con-tributing to the increase in pressure on current interconnections. We proposea Transmission Network Expansion Planning model, including a Stackelberggame, where Transmission System Operators (TSOs) of two market coupledregions act as leader, deciding on the long-term transmission investments,and the follower models the Independent System Operator, responsible fordispatch. The model also includes a portfolio of real options framework, withthe TSOs cooperating and acting as single multi-stage decision-makers withdecisions that are contingent to the uncertain evolution of generation and de-mand. Transmission investment costs are later split between regions using afair share cost allocation procedure based on Nash-Coase bargaining. Usingelectricity bid data from the Iberian Electricity Market and ENTSO-E’s fourVisions for 2030, we study scenarios for the development of Portugal-Spaininterconnections.

Abordagens meta-heurísticas híbridas para o problema deotimização em dois níveis com múltiplos seguidores: uma aplicaçãono mercado retalhista de eletricidade

Inês Soares, Maria João Alves, Carlos Henggeler

Resumo. Na evolução para as redes elétricas inteligentes, é expetável queos comercializadores implementem ofertas comerciais com tarifas dinâmicas.Estas estruturas tarifárias transmitem sinais de preços, induzindo moldar ospadrões de uso dos equipamentos. O objetivo do comercializador é maxi-mizar o lucro enquanto o objetivo dos consumidores é minimizar a fatura deeletricidade. Esta interação pode ser modelada através da programação emdois níveis (bi-level programming - BL). O comercializador define os preçosem cada período horário e os consumidores determinam o funcionamento dosequipamentos tirando partido da flexibilidade temporal, face aos preços erequisitos de conforto. Foram desenvolvidas duas abordagens híbridas de oti-mização BL, considerando um líder (comercializador) e múltiplos seguidores(consumidores), baseadas em meta-heurísticas populacionais: um algoritmogenético (GA) e um algoritmo de otimização por enxames de partículas (PSO)para o problema de nível superior, compreendendo um solver de programaçãolinear inteira mista para resolver o problema do nível inferior. Foram geradosdiferentes cenários, considerando um líder que impõe diferentes esquemas tari-fários e três seguidores com diferentes perfis de consumo. Foram consideradosequipamentos residenciais com diferentes ciclos de operação e analisadas dife-rentes estruturas de preços. Os resultados obtidos revelaram uma consistentesuperioridade da abordagem PSO em relação ao GA.

92 Sessão F5: Energy *

Diagnosing and predicting power transformers condition

Luís Dias, Luís Guimarães, Armando Leitão, Luís Ribeiro,Ricardo Bessa, Manuel Matos, Leonel Carvalho

Resumo. Power transformers are a critical equipment for a distribu-tion system operator (DSO) and generation companies (GenCos) due to thecomplexity and cost of their maintenance and replacement operations. ManyDSOs and GenCos apply condition monitoring to prevent power outages andextend the transformer’s remaining useful life (RUL). Transformer conditionis assess using different tests but the results obtained are often analyzed inde-pendently. To improve this diagnosis, researchers have tried to combine thetest’s results, however, these new methods rely on approaches that are hard tointerpret by decision makers. In this work, we develop two data-driven modelscapable of diagnosing and predicting the transformer condition. In the firstmodel, we apply clustering techniques to group the different transformers bycondition and then use known diagnosis models to classify potential faults.In the second model, we use a log-linear regression to predict the transformerRUL incorporating different factors such as technology, level of operation andweather conditions. In this talk, we describe their practical application, com-pare the models’ advantages/disadvantages against the ones in the literatureand finally expose the obtained results.

Distributed OPF algorithm for radial electric distributionnetworks

Rui Pinto, Ricardo Bessa, Manuel Matos

Resumo. The desire for a deeper distributed renewable energy sources(DRES) penetration within medium voltage (MV) and low voltage (LV) distri-bution grids brings new challenges regarding the technical operation of suchgrids. Conventional optimal power flow (OPF) algorithms rely on central-ized problem formulation. Increasing the number of small-scale generators,PV panels, domestic batteries, electric vehicles, and demand response pro-grammes in MV and LV distribution grids exponentially increases the numberof variables in the OPF problem. Near-future distribution grid operationalparadigm will have to rely on distributed and efficient OPF algorithms forreal-time and non-centralised control. We study a distributed OPF algorithmfor radial distribution grids that is based on the alternating direction methodof multipliers (ADMM) while relaxing the non-convex characteristic of theOPF problem through second-order cone program (SCOP) or semi-definiteprogramming (SDP). ADMM allows the decomposition of the original OPFproblem into local subproblems at the nodal level. Each node optimizes its

Sessão F6: Multiobjective Optimization II 93

own individual problem while communicating with neighbor nodes and thusassuring that global optimal solution is found. Initial results for an AC OPFformulation considering a radial and balanced single-phase distribution gridsare in line with other vastly validated software tool such as MatPower fromMatlab.

Sessão F6: Multiobjective Optimization II7 de Setembro, Sexta-feira, 9:30 - 11:00Sala: 23.3.15

Moderadora: Dalila Fontes

Multi-objective optimization approach to design and planning ahydrogen supply chain in Portugal

Diego F.M. Camara, Tânia Pinto-Varela, Ana Barbosa-Póvoa

Resumo. The transition from the current energy infrastructure to thatin which hydrogen plays an important role as transport energy has been in-creasing the interest of the academic as well as industrial communities. Thisis mainly associated with a context of sustainable development, where it is in-tended to contribute to the reduction of global potential warming by buildingglobal optimized supply chains (SC) that support industrial processes throughrenewable energy sources. Recently, different approaches to modeling a hy-drogen SC have appeared in the literature, as an attempt to determine ifhydrogen is a competitive option, -as an energetic vector while mitigating thehigh capital investment. This is not, however a solved problem. In this con-text, a multi-objective, multi-period mathematical formulation for design andplanning of a hydrogen SC was developed. The developed Mixed Integer Lin-ear Programming (MILP) aims to determine the SC strategic and planningdecisions, considering minimization of cost and environmental impact in thenetwork, taking in account transportation between different regions as wellas local transportation within regions. A study case applied in Portugal wassolved and the results will be discussed.

Supply chain design and planning towards social sustainability

Bruna Mota, Ana Carvalho, Maria Isabel Gomes, Ana Barbosa-Povóa

Resumo. Companies are continuously being pressured to become sustain-able. Environmental sustainability has been the main focus of many studies,

94 Sessão F6: Multiobjective Optimization II

in combination with the economic pillar. Social sustainability continues to bethe far less explored pillar. This happens mostly due to difficulty in quanti-fying these aspects and due to the associated subjectivity. Job creation hasbeen the main social indicator studied and applied in supply chain optimi-sation. This work takes a step forward exploring the job creation indicatorwithin the context of the European Union Sustainable Development Goals.This study aims to understand how different socio-economic indicators affectsupply chain design and planning decisions, and the supply chain economicperformance. Different socio-economic indicators, based on the SustainableDevelopment goals are developed and applied in a multi-objective mixed in-teger supply chain design and planning model. Such indicators are based onGross Domestic Product (GDP) and Unemployment Rate statistics, in ad-dition to straightforward job creation. A real case-study in the automotivecomponents industry is developed. Recommendations on the application ofsocio-economic indicators in supply chain design and planning models are de-rived. A careful choice of the indicators used is recommended to companiesand governmental institutions deciding on how to measure social sustainabil-ity performance.

A multi-criteria genetic algorithm approach to develop workersrotation programs

Pedro Coelho, Leonardo Porto, Cristóvão Silva, NathalieKlément

Resumo. Job rotation is a method of work organization which requiresthe workers to move between different tasks, at fixed or irregular periods oftime. It helps prevents worker’s musculoskeletal disorders, eliminates bore-dom and increases job satisfaction and morale. This may lead to increases inproductivity, employee loyalty and decreases in employee turnover; however,developing effective rotation schedules can be complex in even moderate sizedfacilities. The aim of this study is to suggest a job rotation Schedule for theoperators of a gas bottle preparation unit by employing multi-criteria geneticalgorithm in order to reduce sequential high daily workloads and minimizebetween-worker variability in cumulative daily workloads. The effectivenessof the approach is demonstrated by comparing it results, which take into ac-count workers skills as well as their health disorder, with the cumulative dailyworkloads imposed to the company workers during the year 2016, whereassome of workers were successively assigned to high workload workstation un-der no job rotation. The application of the algorithm presented could be anefficient planner tool in the development of a rotation program that help toreduce the potential for work-related musculoskeletal disorders without any

Sessão F6: Multiobjective Optimization II 95

loss in terms of productivity or quality.

Selection of a strategic plan using multi-objective optimization

Dalila B. M. M. Fontes, Teresa Pereira, Márcia Oliveira

Resumo. In this work we develop a multi-criteria decision making modelto assist in the choice of a strategic plan for word class company. The BalancedScorecard (BSC) is a support tool of Beyond Budgeting that translates acompany’s vision and strategy into a coherent set of performance measures;however it does not provide help in choosing a strategic plan. The selectionof a strategic plan involves multiple goals and objectives that are very oftenconflicting and incommensurable. This paper proposes an integrated AHP- Goal Programming (GP) approach to select such a plan consisting of twostages. In the first stage, the AHP is used to evaluate the relative importanceof the initiatives with respect to financial indicators / KPIs; while in thesecond one a GP model incorporating the AHP priority scores is developed.The GP model selects a set of initiatives that maximizes EBIT and minimizesCapital Employed. The proposed method was evaluated through a case study.


Sessão Plenária 37 de Setembro, Sexta-feira, 11:30 - 12:30Sala: 23.1.6

Moderadora: Helena Alvelos

Da IO à IA - Passando por Machine Learning

António Murta Pathena, Portugal

Resumo. No princípio eram as Operações, e daí a Investigação Opera-cional (IO). Programas processavam Dados e geravam Informação. De Oti-mização e de Heurísticas se tratava – sempre sob a Ameaça Combinatorial delargos espaços de procura. A IO teve muitos filhos – Programação Inteira,Constraint-based-Programming, etc.

Depois veio a Inteligência Artificial – com as abordagens de representaçãodo Conhecimento (potencialmente incompleto e incerto). Esta (IA) cresceu eexpandiu-se por muitas verticais.

Uma veio a ganhar grande preponderância e impacto : a área de MachineLearning. A sua conjugação com a Internet das Coisas e com espaços deBig Data veio tornar possíveis abordagens totalmente novas e com resultadosextraordinários. Programas usavam muitos dados para treinar / melhorar egeravam Programas (Inteligentes).

É deste caminho, da IO à IA, que a apresentação dará conta.

Lista de Moderadores

AAgra, Agostinho . . . . . . . . . . . . . . . . . 52Almeida, João Paulo . . . . . . . . . . . . . 41Alvelos, Filipe . . . . . . . . . . . . . . . . . . . 55Alvelos, Helena . . . . . . . . . . . . . . . . . . 96Alves, Claudio . . . . . . . . . . . . . . . . . . . 71Alves, Maria João . . . . . . . . . . . . . . . 42Amorim, Pedro . . . . . . . . . . . . . . . . . . 88Amorim-Lopes, Mário . . . . . . . . . . . 34Antunes, Carlos Henggeler . . . . . . . 63

BBarbosa-Póvoa, Ana . . . . . . . . . . . . . 47

CCamanho, Ana . . . . . . . . . . . . . . . . . . 82Captivo, Maria Eugénia . . . . . . . . . .45Cerdeira, Jorge Orestes . . . . . . . . . . 84Claro, João . . . . . . . . . . . . . . . . . . . . . . 78

DDias, Joana . . . . . . . . . . . . . . . . . . . . . . 13Dias, Luís C. . . . . . . . . . . . . . . . . . . . . 66

FFerreira, José Soeiro . . . . . . . . . . . . . 29Figueira, Gonçalo . . . . . . . . . . . . . . . . 49Figueira, José Rui . . . . . . . . . . . . . . . 31

Fontes, Dalila . . . . . . . . . . . . . . . . . . . . 93

GGomes, Maria Isabel . . . . . . . . . . . . . 69

MMarques, Inês . . . . . . . . . . . . . . . . . . . .73Matos, Manuel . . . . . . . . . . . . . . . . . . .90Miranda, João Luís . . . . . . . . . . . . . . 60Moura, Ana . . . . . . . . . . . . . . . . . . . . . 57

OOliveira, José Fernando . . . . . . . . . . 12Oliveira, Mónica . . . . . . . . . . . . . . . . . 76

PPato, Margarida Vaz . . . . . . . . . . . . . 27

RRequejo, Cristina . . . . . . . . . . . . . . . . 86

TTchemisova, Tatiana . . . . . . . . . . . . . 25

VVaz, Clara Bento . . . . . . . . . . . . . . . . 39

XXambre, Ana Raquel . . . . . . . . . . . . 67

97

98

Lista de Autores da SessãoEstudIO

AAraújo, Ana Margarida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 23

BBarbosa-Póvoa, Ana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13, 18, 21, 23

CCruz, Lourenço . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 21

LLubomirska, Luísa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 16

MMarques, Inês . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 16, 18, 23

OOliveira, Beatriz Brito . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 14Oliveira, José Fernando . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 14

PPatrão, Mariana J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 18

SSilva, José Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13, 14

99

100

Lista de Autores

PlenáriasAlmada-Lobo, Bernardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66

FEUP, Porto, PortugalDolgui, Alexandre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

IMT Atlantique, Nantes, FrançaMurta, António . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96

Pathena, Portugal

AAgra, Agostinho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35, 54, 56

[email protected] de Aveiro, CIDMA e Departamento de Matemática

Alçada-Almeida, Luís . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63, [email protected] de Coimbra, Faculdade de Economia

Almada-Lobo, Bernardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35, 52, 61, 62, 69, 71, 72, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Almeida, João . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Bragança, LIAAD-INESC TEC e CeDRI

Alvarenga, António . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa

Alvarez, Margarita Rodríguez . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Alicante, Espanha

Alvelos, Filipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55, 57, [email protected] do Minho, Centro Algoritmi e Departamento de Produção e

SistemasAlves, Carlos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

[email protected] do Porto, INESC-TEC e Faculdade de Engenharia

101

102 Lista de Autores

Alves, Cláudio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71, [email protected] do Minho

Alves, Marco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

Alves, Maria João . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44, [email protected] de Coimbra, CeBER e Faculdade de Economia

Amaral, Paula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] NOVA de Lisboa, DM/FCT e CMA

Amorim, Francisco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] e Universidade do Porto, Faculdade de Engenharia

Amorim, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35, 47, 53, 67, 68, 71, 83, 86, 87, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Amorim-Lopes, Mário . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 37, 51, 61, [email protected] do Porto, INESC TEC e Faculdade de Engenharia; Católica

Porto Business SchoolAndrade, Xavier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28

[email protected] do Porto, INESC TEC e Faculdade de Engenharia

Antunes, António . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69, [email protected] de Coimbra, CITTA e Departamento de Engenharia Civil

Antunes, David . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, CITTA e Departamento de Engenharia Civil

Assef, Fernanda Medeiros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50, [email protected]ícia Universidade Católica do Paraná, Brasil

Azevedo, Américo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Engenharia

BBárcia, Paulo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .85

[email protected] NOVA de Lisboa, Nova School of Business and Economics

Bandeira, Luís Miguel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Engenharia

Barbas, Marta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .37


[email protected] de Lisboa

Barbosa, Cátia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Barbosa, Fábio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Telecomunicações, Universidade de Aveiro

Barbosa, Flávia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Barbosa-Póvoa, Ana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27, 34, 37, 45, 49, 70–72, 86, [email protected] de Lisboa, CEG-IST e Instituto Superior Técnico

Barros, Ana Cristina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71, [email protected] TEC

Bastos, João . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, Instituto Superior de Engenharia

Batista, Bruno . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

Beliën, Jeroen . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Leuven Campus Brussels, Bélgica

Bergiante, Nissia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Federal Fluminense, Brasil

Bertoluci, Ricardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, Instituto Superior de Engenharia

Bessa, Ricardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Bianchi-Aguiar, Teresa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31, [email protected]

Borbinha, José . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior Técnico

Borges, Alexandra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Viana do Castelo

Borges, Ana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]


Politécnico do Porto, ESTGBorges, José Luís . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

[email protected] do Porto, INESC TEC e Faculdade de Engenharia

Bottero, Marta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Turim, Itália

CCaçador, Sandra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

[email protected] de Aveiro, ISCA; Universidade de Coimbra, CeBER e Faculdade

de EconomiaCamanho, Ana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40, 83

[email protected] do Porto, Faculdade de Engenharia

Camara, Diego F.M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior Técnico

Campelo, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

Cappanera, Paola . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Florença, Itália

Captivo, Maria Eugénia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46, [email protected] de Lisboa, CMAF-CIO e Faculdade de Ciências

Cardoso, Domingos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, CIDMA e Departamento de Matemática

Cardoso-Grilo, Teresa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Universitário de Lisboa, ISCTE e CEG-IST

Carravilla, Maria Antónia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Carvalho, Ana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70, 71, [email protected] de Lisboa, CEG-IST e Instituto Superior Técnico

Carvalho, Ana Sofia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CMAF-CIO

Carvalho, Bruno de . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79Universidade de Lisboa, CERIS e Instituto Superior Técnico

Carvalho, Filipa Duarte de . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85


[email protected] de Lisboa, ISEG e CMAF-CIO

Carvalho, José Manuel Valério de . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Minho

Carvalho, Leonel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Carvalho, M. Sameiro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .64, [email protected] do Minho, Departamento de Produção e Sistemas

Castro, Eduardo A. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, GOVCOPP

Cerdeira, Jorge Orestes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] NOVA de Lisboa, DM/FCT e CMA

Chibeles-Martins, Nelson . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] NOVA de Lisboa

Christiansen, Marielle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] University of Science and Technology, Noruega

Claro, João . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36, 79, 80, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Coelho, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, CEMMPRE

Constantino, Miguel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Faculdade de Ciências

Costa, Alysson M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] University of Melbourne, Australia

Costa, Ana Sara . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CEG-IST e INESC-ID, Instituto Superior Técnico

Costa, Anabela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Universitário de Lisboa, ISCTE e CMAF-CIO

Costa, Carlos Bana e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior Técnico

Costa, João Bana e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]


Bana Consulting LDACosta, Lino . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64

[email protected] do Minho, Departamento de Produção e Sistemas

Costa, Patrícia L. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Universitário de Lisboa, ISCTE

Coutinho-Rodrigues, João . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63, [email protected] de Coimbra, Departamento de Engenharia Civil

Couto, Mário . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto

Cruz-Gomes, Sofia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Cunha, Nuno Falcão e . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35, [email protected] do Porto, Faculdade de Engenharia

Cunha, Ricardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

Curcio, Eduardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55, 67, [email protected] TEC

Custodio, Ana Luísa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] NOVA de Lisboa, DM/FCT e CMA

DDíaz-Madroñero, Manuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72

[email protected] Politécnica de Valência, Espanha

Dias, Joana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41, 44, 45, 63, [email protected] de Coimbra, CeBER, INESC Coimbra e Faculdade de Economia

Dias, Luís . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Dias, Luís C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33, [email protected] de Coimbra, CeBER, INESC Coimbra e Faculdade de Economia

EEspadinha, Daniel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89


[email protected] Universitário de Lisboa, ISCTE

FFajardo, Maria Dolores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

[email protected] de Alicante, Espanha

Fenerich, Amanda Trojan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50, [email protected]ícia Universidade Católica do Paraná, Brasil

Ferreira, Ângela Paula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Bragança

Ferreira, Brigida . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, ESTSP

Ferreira, Carlos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, DEGEIT

Ferreira, Carolina Correia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] NOVA de Lisboa, Departamento de Física, FCT

Ferreira, Cristiane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Ferreira, Denise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, DEGEIT

Ferreira, Diogo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior Técnico

Ferreira, José Soeiro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Engenharia

Ferretti, Valentina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] School of Economics and Political Science, Reino Unido

Figueira, Gonçalo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 47, 51–53, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Figueira, José Rui . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32, 33, 76, [email protected] de Lisboa, CEG-IST e Instituto Superior Técnico

Figueiredo, Ana Sofia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Engenharia


Fischbeck, Paul . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Melon University, Estados Unidos

Fontes, Dalila B.M.M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41, [email protected] do Porto, Faculdade de Economia

Franco, David Gabriel de Barros . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]ícia Universidade Católica do Paraná, Brasil

Fransoo, Jan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]/e, Holanda

GGamboa, Dorabela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

[email protected]écnico do Porto, CIICESI e ESTG

Gan, Thiam-Soon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Técnica de Munique, Alemanha

Girão, Luís . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, [email protected] TEC

Godinho, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, CeBER e Faculdade de Economia

Gomes, André . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra

Gomes, Maria Isabel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32, 70, [email protected] NOVA de Lisboa, DM/FCT e CMA

Gomes, Marta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CERIS, CESUR e Instituto Superior Técnico

Gonçalves, João N.C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Minho, Centro Algoritmi

Gonçalves, José Fernando . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Economia

Grünow, Martin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Técnica de Munique, Alemanha

Greco, Salvatore . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33, [email protected]


Universidade de Catania, Itália; CORL, Universidade de Portsmouth, UKGuapo, Joana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49


Guimarães, Luís . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28, 72, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

HHenggeler, Carlos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

[email protected] de Coimbra, INESC Coimbra e DEEC-UC

Henriques, Alda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Engenharia

Hvattum, Lars Magnus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] University College, Noruega

JJaarsveld, Willem van . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

[email protected]/e, Holanda

Jacquillat, Alexandre . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Mellon University (CMU), Estados Unidos

Janssens, Gerrit K. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Hasselt, Bélgica

KKlément, Nathalie . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48, 94

École Nationale des Arts et Mé[email protected]

Klimentova, Xenia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Kroef, Marcel Da Silva Van Der . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra

LLami, Isabella Maria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

[email protected]écnico de Turim, Itália

Leitão, Armando . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]


Universidade do Porto, Faculdade de EngenhariaLeite, Mário . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

[email protected] do Minho

Lencastre, Mónica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] NOVA de Lisboa

Lopes, Diana F. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, GOVCOPP

Lopes, Isabel Cristina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, LEMA, CEOS.PP, ISCAP

Lopes, Manuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, Instituto Superior de Engenharia

Lopes, Maria do Carmo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected], EPE

Lopes, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, Instituto Superior de Engenharia

Lopes, Rui Borges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, CIDMA e DEGEIT

Loureiro, Manuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

MMacário, Rosário . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78

[email protected] de Lisboa, CERIS, CESUR e Instituto Superior Técnico

Macedo, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, CIDMA e Departamento de Matemática

Machado, Francisco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Engenharia

Maganha, Isabela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra

Maia, Fábio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, ESTG

Malarranha, Carlos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71


[email protected] de Lisboa, Instituto Superior Técnico

Marques, Alexandra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Marques, Gonçalo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Maretec e Instituto Superior Técnico

Marques, Inês . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45, [email protected] de Lisboa, Instituto Superior Técnico

Marques, Manuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] e Universidade do Porto, Faculdade de Engenharia

Marques, Maria do Céu . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Coimbra, ISEC; Institute for Systems Engineering and

Computers at CoimbraMarques, Rui . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32, 39, 79, 82

[email protected] de Lisboa, CERIS e Instituto Superior Técnico

Martins, Ana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, DEGEIT

Martins, Carlos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CEMAPRE e ISEG

Martins, Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Faculdade de Ciências

Martins, Isabel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior de Agronomia

Martins, Sara . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Mascarenhas, Edgar Sanches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Mataloto, Inês . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior Técnico

Matos, Manuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Matos, Telmo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56


[email protected]écnico do Porto, CIICESI e ESTG

Mello, João Carlos Soares de . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Federal Fluminense, Brasil

Melo, Teresa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Ciências Aplicadas, Saarbrücken, Alemanha

Mendes, Diana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Universitário de Lisboa, ISCTE e BRU

Mendes, Vivaldo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Universitário de Lisboa, ISCTE e BRU

Miguéis, Vera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Miranda, Diogo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] e Universidade do Porto, Faculdade de Engenharia

Miranda, João Luís . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Portalegre, ESTG e CERENA/IST

Moniz, Samuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Monnerat, Filipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, CeBER e Faculdade de Economia

Monteiro, Tiago . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Morais, Carolina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CEG-IST e Instituto Superior Técnico

Morais, Jéssica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Maretec e Instituto Superior Técnico

Moreira, Maria Rosário Alves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, Faculdade de Economia

Moretti, Antônio Carlos . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Campinas, Brasil

Mota, Bruna . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]


Universidade de Lisboa, Instituto Superior TécnicoMoura, Ana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43, 59, 67

[email protected] de Aveiro, DEGEIT

NNeiva, Mafalda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

[email protected] NOVA de Lisboa, Departamento de Física, FCT

Nelas, José . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, Faculdade de Economia

Neto, Pedro José Steiner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50, [email protected] Positivo, Brasil

Neto, Teresa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Viseu

OOdoni, Amedeo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

[email protected] Institute of Technology, Estados Unidos

Oliveira, Beatriz B. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Oliveira, Fábio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Minho, Centro Algoritmi

Oliveira, Gabriela . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, Departamento de Engenharia Mecânica

Oliveira, José . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54, [email protected] de Lisboa, CERIS, CESUR e Instituto Superior Técnico

Oliveira, José Fernando . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 44, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Oliveira, Márcia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Technologies

Oliveira, Mónica . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31, 37, [email protected] de Lisboa, Instituto Superior Técnico

Oliveira, Rui . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CERIS, CESUR e Instituto Superior Técnico


Oliveira, Tiago M. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Centro de Estudos Florestais e Instituto Superior de

Agronomia

PPérez, José Vicente . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

[email protected] de Alicante

Pacheco, Abílio Pereira . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36, [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Pascoal, Marta . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, CMUC e Departamento de Matemática

Pata, Arminda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Viana do Castelo

Pato, Margarida Vaz . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CMAF-CIO e ISEG

Paulo, Helena . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Lisboa, ISEL

Pedroso, João Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58, 61, [email protected] do Porto, INESC TEC e Faculdade de Ciências

Pereira, José M.C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Centro de Estudos Florestais e Instituto Superior de

AgronomiaPereira, Miguel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

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Pereira, Paulo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

Pereira, Teresa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, Instituto Superior de Engenharia

Pilar, Maria de Fátima . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico do Porto, ESTG

Pimentel, Carina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, GOVCOPP e DEGEIT


Pinheiro, Sofia J. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, CIDMA e Departamento de Matemática

Pinho, João . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] da Conservação Natureza e das Florestas IP

Pinho, Leandra . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Aveiro, DEGEIT

Pinto, Alberto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, LIAAD-INESC TEC e Faculdade de Ciências

Pinto, Francisco Silva . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CERIS e Instituto Superior Técnico

Pinto, Rui . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Pinto, Telmo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71, [email protected] do Minho

Pinto-Varela, Tânia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34, 49, 71, 72, [email protected] de Lisboa, CEG-IST e Instituto Superior Técnico

Porto, Leonardo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, Departamento de Engenharia Mecânica

Prazeres, Mafalda . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior Técnico

QQueiroga, José . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

[email protected]

RRamaekers, Katrien . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

[email protected] de Hasselt, Bélgica

Ramos, Filipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Universitário de Lisboa, ISCTE

Ramos, Galrão . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30, [email protected]écnico do Porto, Instituto Superior de Engenharia

Ramos, Tânia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86


[email protected] de Lisboa, CEG-IST e Instituto Superior Técnico; Instituto

Universitário de Lisboa, ISCTE e BRURaposo, Mariana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37


Reis, Vasco . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CERIS, CESUR e Instituto Superior Técnico

Relvas, Susana . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, Instituto Superior Técnico

Requejo, Cristina . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54, [email protected] de Aveiro, CIDMA e Departamento de Matemática

Ribeiro, João Pires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CEG-IST

Ribeiro, Luís . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Ribeiro, Nuno Antunes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, CITTA

Ribeiro, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

Rocha, Humberto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Coimbra, CeBER, INESC Coimbra e Faculdade de Economia

Rodrigues, Ana Maria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] - P. Porto e INESC TEC

Rodrigues, Filipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35, [email protected] de Aveiro, CIDMA e Departamento de Matemática

Rodrigues, Helena Sofia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]écnico de Viana do Castelo

Rodrigues, José Coelho . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] do Porto, INESC TEC e Faculdade de Engenharia

Rosa, Joana Namorado . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa


Roy, Bernard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] Paris-Dauphine, PSL Research University, CNRS (UMR 7243),

LAMSADE, França

SSalvador, Bonifacio . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

[email protected] de Valladolid, Espanha

Santos, Andreia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] de Lisboa, CEG-IST e Instituto Superior Técnico

Santos, Maria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected] TEC

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Schuller, Pedro . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [email protected]

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