1. An Introduction to Systems Analysis and Modelling (1).pptx

8/16/2019 1. An Introduction to Systems Analysis and Modelling (1).pptx

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An Introduction toSystems Analysis

and Modelling

Dr Kristin Stock


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OutlineWhat, Why, When and Where?

Diferent levels o modelling (conceptual, low leveletc!

"odelling and Design # what is design, how does itrelate to what we will cover in this course?

$he systems development liecycleSystems development methodologies

Systems analyst roles and skills

%ro&ect management, especially re 'S) $ools


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What is Systems nalysisand "odelling?

*ow doprogrammersknow what to write

in their code?


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What is Systems nalysisand "odelling?Systems analysis and modelling is a process

o+identiying the prolem that needs to e

solved

analysing the current situation

identiying re-uirements or the new systemmodelling those re-uirements in a systematic

way

creating a clear speci.cation o what the

system must do


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What is Systems nalysisand "odelling?When we talk aout specifying what the

system must do, speci.cally this can include+What data is needed

$he rules that govern that data

$he rules or how that data will e processed

$he layout o user interaces, reports, etc/ules aout access constraints

)0pectations aout the perormance o thesystem


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1s it aout designing a

system?

Well2yes, utthere arediferentde.nitions o

design


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What is the diference etweenanalysis, modelling and design?

nalysis is prolem ocussed

Design is solution ocussed3ut one morphs into the other through the

process

$he tools we use or analysis are also used or

designWe model the e0isting process, and then we

model our design o the new process

We can sometimes use this to generate code2


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Why Systems nalysis and Design? $o ensure the system meets the

needs it is intended to meet

$here is a long history oe0pensive 1$ systems that ailed tomeet user needs

$o ensure system -uality

$o ensure a good .t with the 1$environment

4ltimately2 to provide value tothe organisation


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)0amples o %ro&ect 5ailures6ational *ealth Service, 4K http+77calleamcom7W$%57?p89::;

$ransit $icketing uthority, "elourne,ustraliahttp+77calleamcom7W$%57?p8>

http://calleam.com/WTPF/?p=2003http://calleam.com/WTPF/?p=455http://calleam.com/WTPF/?p=1881http://calleam.com/WTPF/?p=1881http://calleam.com/WTPF/?p=1881http://calleam.com/WTPF/?p=455http://calleam.com/WTPF/?p=455http://calleam.com/WTPF/?p=2003http://calleam.com/WTPF/?p=2003


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$he systemsanalyst+

translates,connects

communicates

ridges the gapetween the

users7organisation and the

technologicaldetails


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When?/ight at the eginning@

When the pro&ect idea

is .rst ormed, somesystems analysisactivities areappropriate

'an continuethroughout, dependingon SDA' methodology


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Where? $he systems analyst needs to spend

time with the users

6eed to oserve and understand thecurrent situation, systems andenvironment

$his is the oundation or a good

system speci.cation


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Diferent Aevels o

"odelling

'onceptual

Aogical

%hysical

1ncreasing levels o detail


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'onceptual nalysis and "odelling*igh level

Sketches out road concepts

'an work with users to de.ne high levelconcepts

eg 'oncept "apping

house street city

is inis in


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Aogical nalysis and

"odelling"uch more detailed

1ndependent o implementation

Does not depend on a particular operatingsystem, sotware or hardware

1mplementation decisions can e madeseparately, later

'hanges in the implementation do not afectthe logical design

%1" 8 platorm independent model


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%hysical nalysis and "odelling"oves rom logical design into design on a

particular operating system, hardware,sotware

)g 'reating the actual dataase tales,creating sotware classes etc

Some tools are availale to generate some

parts o the physical design rom the logicaldesign models

)g logical dataase design can e used togenerate speci.c Oracle, SBA Server

dataases


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Systems Development

Aie 'ycle (SDA'!


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$he SDA' %rocess

$he process consists o our phases

)ach phase consists o a series o steps)ach phase is documented

(deliverales!

%hases are e0ecuted se-uentially,incrementally, iteratively or in someother pattern


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Buestions to e

nswered%lanning phaseWhy should we uild this system?

What value does it provide?

*ow long will it take to uild?

nalysis phaseWho will use it?

What should the system do or us?Where C when will it e used?

Design phase*ow should we uild it?

1ncreasinglevels odetail


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SDA'+ $he %lanning

%hase> %ro&ect 1nitiationDevelop7receive a system

re-uest'onduct a easiility analysis

9 %ro&ect "anagementDevelop the work plan

Staf the pro&ect"onitor C control the pro&ect

Deliverale+ Work

%lan


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SDA'+ $he nalysis %hase> Develop an analysis strategy

"odel the current system

5ormulate the new system9 ather the re-uirements

Develop a system concept

'reate a usiness model to

represent+

3usiness data

3usiness processes

; Develop a system proposal

Deliverale+ nalysisand *ighE

AevelDesign


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SDA'+ $he Design %hase> Develop a design strategy

9 Design architecture and interaces

; Select hardware, sotware, networkinrastructure!


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word aout

speci.cations2/e-uirements speci.cationWhat is re-uired o the system?

*igh level

5unctional speci.cationWhat unctions must it provide?

What usiness processes must it support?

Design speci.cationDetails o design, including user interaces,

what each utton does etc

Do we need all three?


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SDA'+ $he 1mplementation

%hase

> 'onstruct the system

3uild it (write the programming code!

$est it

9 1nstall system

$rain the users; Support the system

(maintenance!


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SDA'+ "ethodologies"ethodology+ a ormaliFed approach to

implementing the SDA'

'ategories3y area o ocus%rocess orientedData centeredO&ectEoriented

3y se-uencing and emphasis o phases+Structured/apid action development

gile development


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'lasses o

"ethodologiesStructured DevelopmentWaterall Development

%arallel Development/apid pplication

Development%hased

%rototypinggile DevelopmenteGtreme %rogrammingS'/4"


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Structured "ethodologies4sed commonly in >H:s

/eplaced adEhoc approach

5ormal, se-uential, stepEyEstep


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Waterall Development%roceeds se-uentially rom one step to the ne0t

Aots o documentation, approved at each step

'anIt go ackwards

dvantages+

/e-uirements are identi.ed long eore programmingstarts

/e-uirements do not change

Disadvantages+

1 re-uirements are missed,e0pensive postEimplementation changesre-uired

Does not cater or changes in

the environment


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%arallel Developmentter a general high level design, suEpro&ects

are created

SuEpro&ects designed and implemented inparallel

SuEpro&ects integrated at the end

dvantages+

/educes time or total development, so lesschange in environment

Disadvantages+SuEpro&ects may e interdependent, so

integration is diJcult


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/apid pplication

DevelopmentStarted to e used in >HH:s

$ry to get some parts o the systemdeveloped -uickly and out to users oreedack

dvocate the use o 'omputer ided Sotware)ngineering ('S)! tools, oint pplication

Design (D! sessions, visual programmingtools, code generators

'an result in Lscope creepI # re-uirementschange and increase as users work with the

system


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%hased Development3egins with a high level design o the system concept

De.nes a series o versions, with ever increasingunctionality

5or each version, there is analysis, design,

implementation, release to users'ontinues until system complete or osolete

dvantages+ets something in the hands o the users -uickly, so early

value to organisation

'an also identiy prolems and changed re-uirements early

Disadvantages+4sers are working with an incomplete system

4ser e0pectation management


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%rototyping1terative

Mery preliminary design used to create .rst prototype

radually re.ned

nalysis, design and implementation perormed

concurrentlyll iterative

dvantages+)arly user involvement and eedack

Disadvantages+Such rapid change that methodological design and

analysis is diJcult

'an e very ineJcient


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$hrowaway %rototypingdopts a more

conventional waterallprocess overall, ut

prototypes are uilt alongthe way, then discarded

%rototypes address speci.cissues

)ach prototype has its ownanalysis, design,implementation cycle, andis used to re.ne thedesi n


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gile Development"ost recent

"ore ocussed around design philosophiesthan speci.c details o methodology

5ollow the >9 principles+Sotware is delivered early and continuously

'hanging re-uirements are emraced

'ustomers and developers work together5ace to ace communication is key

5ocus on technical e0cellence and good design

/egular reNection


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Drawacks o gile Development/e-uire coElocation o

development team

$he process i not highlymanaged (y de.nition!, so canturn into Lprogrammers gonewildI, hacking togethersolutions

Aittle documentation

Suitale or large, missioncritical systems?


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)0treme %rogramming'ommunication, simplicity, eedack,

courage

5eedack to users continuously

)mrace change

Buality .rst

$esting is continuous

)volutionary, incremental*eavy onEsite user input

/elies on a small, closeEknit team


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Scrum"ade up o ;: day sprints

)ach sprint delivers a system to the

user

6o re-uirements changes during a

sprintScrum meeting each day+%revious dayIs accomplishments

%lan or today

ny ostaclesgain, may not e suitale or large

pro&ects


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Which "ethodology to

4se?


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What kind o person is involvedin Systems nalysis?

gents o change

1dentiy ways to improve the organiFation"otivate C train others

ility to see oth technical and user sides oa prolem

3ig picture plus detail


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Skills needed or Systemsnalysis

Skills needed+ $echnical+ must understand the technology

3usiness+ must know the usiness processes

nalytical+ must e ale to solve prolems

'ommunications+ technical C nonEtechnicalaudiences

1nterpersonal+ leadership C management

)thics+ deal airly and protect con.dentialinormation


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os involving Systems nalysis3usiness nalyst5ocuses on the usiness issues

Systems nalyst

5ocuses on the 1S issues

1nrastructure nalyst5ocuses on the technical issues

'hange "anagement nalyst

5ocuses on the people and management issues

%ro&ect "anager

)nsures that the pro&ect is completed on time and withinudget

Systems rchitect

Data "odeller

4ser 1nterace71nteraction Designer


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1$ %ro&ect "anagement%ro&ect "anagement is the process o planning and

controlling system development within a speci.ed

time at a minimum cost with the right unctionality

pro&ect is a set o activities with a speci.edeginning and end point meant to create a systemthat rings value to the usiness

%ro&ect "anagers monitor and control all tasks androles that need to e coordinated

nalysis and "odelling are key to the success o 1$pro&ects


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Spectacular 1$ pro&ect

ailures4K prison 1$ system+http+77wwwFdnetcom7article7ukEprisonEitEmassiv

eEandEspectacularEailure

7See reading rom 6elson, 9:: on Stream

http://www.zdnet.com/article/uk-prison-it-massive-and-spectacular-failure/http://www.zdnet.com/article/uk-prison-it-massive-and-spectacular-failure/http://www.zdnet.com/article/uk-prison-it-massive-and-spectacular-failure/http://www.zdnet.com/article/uk-prison-it-massive-and-spectacular-failure/http://www.zdnet.com/article/uk-prison-it-massive-and-spectacular-failure/http://www.zdnet.com/article/uk-prison-it-massive-and-spectacular-failure/


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Why are ailures so

common?4nderestimating time and efort4nreasonale demands7e0pectations

4se o unknown7new technologies $oo much ocus on technology+Driven y technology rather than usiness

value

5ailing to take human, organisational, culturalaspects into account


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%ro&ect 1denti.cation usiness need is identi.ed # management,usiness unit, 1$ department, e0ternal (egpoliticians, senior management!

'ould result rom some prolem (losingmarket share etc!

Speculative pro&ect identi.cation

$he usiness need should drive the high levelre-uirements


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$he System /e-uest document that descries the reasons or and the

value added rom uilding a new system

'ontains = elements+• %ro&ect sponsor+ the primary point o contact or the

pro&ect

• 3usiness need+ the reason prompting the pro&ect

• 3usiness re-uirements+ what the system will do

• 3usiness value+ how will the organiFation ene.t romthe pro&ect

• Special issues+ nything else that should e considered


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What is a 3usiness 'ase?'ommonly (and loosely! used term to

descrie a document that &usti.es why asystem should e uilt7changed7upgraded

'an range rom a couple o paragraphs to alengthy document

1 you want to spend time or money on apro&ect, you will need to make the case to

management


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5easiility nalysis1s this pro&ect easile?What are the risks?

'an these risks e overcome?

"a&or components+ $echnical easiility ('an we uild it?!

)conomic easiility (Should we uild it?!

OrganiFational easiility (Will they use it?!


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$echnical 5easiility1dentiy risks in the ollowing areas+ $he unctional area+ re analysts amiliar

with this portion o the usiness? $he technology+ Aess amiliarity generates

more risk

%ro&ect siFe+ Aarge pro&ects have more risk

'ompatiility+ DiJcult integration increasesthe risk


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)conomic 5easiility('ostE3ene.t nalysis!

1dentiy the costs and the ene.ts

ssign values to the costs and ene.tsDetermine the cash Now

Determine the value using one or moremethods+

6et present value (6%M!/eturn on investment (/O1!

3reakEeven point


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5ormulas or Determining

Malue


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)0ample 'ostE3ene.t

nalysis


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)0ample 3reakE)ven

%oint


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OrganiFational 5easiilityWill the users accept the system?

1s the pro&ect strategically aligned with the

usiness?'onduct a stakeholder analysis%ro&ect champion(s!

OrganiFational management

System usersOthers


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%ro&ect Selection%ro&ects are approved, declined or delayed

ased on value added vs risks

%ro&ect portolio managementoals+"a0imiFe cost7ene.t ratio

"aintain an optimal mi0 o pro&ects ased on+/iskSiFe, cost C length o time to complete

%urpose, scope C usiness valueAimited resources re-uire tradeEofs

Selected pro&ects enter the pro&ectmanagement process

%ro&ect "anagement


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%ro&ect "anagement $oolsids in creating workplans

1dentiy all tasks, their se-uence and estimate thetime to complete each one

Work reakdown structures (W3S!+ a hierarchy otasks to identiy+Duration o each task'urrent status o each task $ask dependencies (shows which tasks must e

completed eore others can egin!antt charts+ horiFontal ar chart that shows the

W3S graphically

6etwork diagrams+ %)/$ and '%"


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antt 'harts

Show tasks, duration, start and end andresources (eg staf! in graphical ormat


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(ctivity

> Study conte0tual aspects that contri,ute to language use and interpretation in )nglish

9 Study use of spatial relations in "aori

; Study conte0tual aspects that contri,ute to language use and interpretation in "aori

< 'ompare )nglish and "aori spatial language models and conte0tual aspects

; Develop of Spatial 'onte0t Ontology

< Develop of model for conte0tual language use

= Develop of reasoning method

P )valuate models against test data and iteratively improve

Qear > Qear 9 Qear ;


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Scope "anagementScope RcreepOccurs ater the pro&ect is underway

/esults rom adding new re-uirements to the pro&ect

'an have a deleterious efect on the schedule $echni-ues to manage the pro&ect scope+ 1dentiy all re-uirements at the outset

llow only those changes deemed asolutely necessary

'areully e0amine the impact o suggested changesDelay some changes or Ruture enhancements

$ime o0ing


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)nvironment C 1nrastructure

"anagement

)nvironmentT'hoose the right set o tools4se appropriate 'S) tools to+

1ncrease productivity and centraliFe inormation (repository! 4tiliFe diagramsTmore easily understood

)stalish standards to reduce comple0ity

1nrastructureTDocument the pro&ect appropriately

Store deliverales C communications in a pro&ectinder

4se 4ni.ed %rocess standard documents

DonIt put of documentation to the last minute


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'ase Study+ ustralian 'apital $erritory SD"S

oal+ to automate, record, enale landadministration

$wo e0isting systems+'D system

Oracle ased te0tual system

/e-uirement+ a single integrated system tosupport all usiness unctions


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'ase Study+ ustralian 'apital $erritory SD"S

Waterall model

5irst analysed e0isting systems andprocesses

Designed new processes

Designed user interaces and applications to

support those processes


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'ase Study+ ustralian 'apital $erritory SD"S # Aessons Aearnt

"assive scope creep

"oved to phased methodology4ser involvement much too late in the

process

5ull set o speci.cations+ re-uirements,

unctional, designDesign spec impractical

Mery comple0 system technically andorganisationally


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Documents

1. An Introduction to Systems Analysis and Modelling (1).pptx