FRE 2672

Urban Ontologies : the Towntology prototype towards case studies

Chantal BERDIER (EDU),

Catherine ROUSSEY (LIRIS)

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Ontology DefinitionsGruber 1993: « the specification of conceptualisations, used

to help programs and humans share knowledge.  »  

Studer 1998 : « Ontology is a formal and explicite specification of a share conceptualisation.  »  

  The conceptualization is an abstract, simplified view of the world that

has to be represented for some purpose.

The specification is the representation of this conceptualization in a concrete form. The goal is to create an agreed-upon vocabulary and semantic structure for exchanging information about that domain.

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Ontology ObjectivesExpert System Knowledge based System

Knowledge separation from treatment in order to solve a specific problem or to achieve a task.

Knowledge reuse in different systems

Problem Solving MethodMethod input Method output

Method ontology

Application ontology

Domain ontology

Described by

mappingExtended to

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4 Ontology Classifications

Classification according to :

1.Formalization,

2.Expressiveness,

3.Purpose,

4.Specificity

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Classification according to Formalization

Depend on the language used to describe the ontology

highly informal: Yahoo directory

semi-informal: French Architecture Thesaurus

semi-formal: Dublin Core metadata Initiative in RDF.

rigorously formal: measurement ontology in KIF.

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Classification according to Expressiveness

Terms

Natural Language Definition

Concepts, class, type

Relation type, property type

Concept taxonomy

Relation type taxonomy

Properties and Attributes

Constraints

Formal definition

Axiom, facts

Rules

Lightweight Ontology

Heavyweight Ontology

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Classification according to Purpose Application ontology Ontolingua,

Protégé

Reference ontology PSL standard

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Classification according to SpecificityGeneric Ontology

Generic concept applicable on many fields

Example: measure concept

Core Ontology Core concept of urban domain applicable to urban field

Example: network concept

Domain Ontology Specific Concepts of a field.

Example: electricity network.

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Towntology ProjectFormalization: Semi informal / formal ontology

Expressiveness Lightweight Ontology

Purpose Reference ontology

Specificity Domain ontology

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Towntology Browser Semantic networkList of terms

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Image Browser

List of conceptsInteractive zones

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Towntology Browser: Information Frame

relations definitions Imagereferences

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Road System Ontology

roadway

Track

Bridge

Giratory

Structure

Draining road

PavementCycle strip

Cycle path

Urban trip

Building outline

Road way structure

Hierarchical Road

Road

Auscultation

Black

Undulation

Sevader

has tool

is a

is used for

is a computing tool forhas problem

has activity about

characterizeis located on

is composed ofhas tool

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Road System Visualisation in Context

ArbreCandélabre

Transport en commun

Potence

Feu de signalisation

Stationnement

Bordure

gauche

Marquage au sol

Figurine piéton

Potelet

Plaque de rue

Chaussée

Tree

Public transport

Desactivated concrete

bracket

Traffic lights

Parking

Kerb

Pedestrian crossing

Road marking

Pedestrian figurine

Road way

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7 classes of relationship typesRelation of localization « is located on » « is located in »

Relation of use : « is used for » « is used by » « can hold the role »

Relation of composition : « is composed of »

Relation of subordination : « depends on » « works for »

Relation of being : « is a(n) »

Relation of characterization « is characterized by » « says itself for »

Relation of generation: « is resulting from »

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Urban Mobility Ontology

Mode of transportationCaptive

User of road

Pedestrian

Car

walking cycling

Bus

Mean of public

transport

Noise Nuisance

Pollution

ExternalityDisabled person

Motorized mode of transportationMode of transportation not

motorized

Tramway Subway

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Urban Renewal Ontology

Urban renewal demolition

High rise estate

Is located on

reconstruction

Is composed of

Is followed by

operation

Is a

Social problem

unemployement

Is resulting from

educational failure

Is characterized by

Family of numerous childs

Functionalism theory

form

Construction period

Industrial techniques of building

Is linked

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Towntology report

To add the attributes and measurements

To develop a base of knowledge

Description of a particular situation

Example: the rehabilitation of the Lacassagne street in Lyon.

Limit of the tool :

All the concepts are represented in the same way

No visible hierarchy of concepts (identification of the level of specialization, or degree of association of the concept)

no filter on the domain/level, etc…

no regrouping of similar concepts in various fields (example : operation)

No global vision of the complexity of certain urban fields (example : urban renewal)

Sometimes a simplistic modelling of the field.

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Guidelines To make a good choise of Domain : technical

domain is easier Consensus and mathematical rigour

Documentation (dictionary, books, standards)

To think about the meaning of relations upstream Hierarchical relation

To think about general concepts and core concepts « general concepts » enable to build a good hierarchy

To define the difference between « brother concepts ».

To limit the number of relations

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Conclusion

All the fields of urban are not necessarily formalisable. A minimum of stability in the definitions is required.

Urban is able to generate any kind of ontology: formal, informal etc...

For example : technical fields of urban like roadway system can give rise to a formal ontology

Urban renewall for example give rise to abstract ontology.It Is a constructing domain.

One should not seek to make consensus but to create footbridges between various levels of vocabularies...