management information systems 8/e raymond...
TRANSCRIPT
Chapter 7System Life CycleSystem Life Cycle
MethodologiesMethodologies
MANAGEMENT INFORMATION SYSTEMS 8/ERaymond McLeod, Jr. and George Schell
Copyright 2001 Prentice-Hall, Inc.7-1
OBJECTIVESOBJECTIVES
Realize that the development and use of aRealize that the development and use of acomputer-based system progresses through a lifecomputer-based system progresses through a lifecycle, and that users and information specialistscycle, and that users and information specialistsplay key roles in each phaseplay key roles in each phaseBe aware of the MIS steering committee, theBe aware of the MIS steering committee, thefunctions that it performs, and the advantages thatfunctions that it performs, and the advantages thataccrue from its participation in the life cycleaccrue from its participation in the life cycleKnow the benefits that can be expected fromKnow the benefits that can be expected fromplanning the system life cycleplanning the system life cycle
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The Systems Life Cycle (SLC)The Systems Life Cycle (SLC)
MethodologyMethodology–– Recommended way of doing somethingRecommended way of doing something
An application of the systems approachAn application of the systems approachto the task of developing and using ato the task of developing and using acomputer-based systemcomputer-based systemOften called waterfall approachOften called waterfall approach
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Phases in the SDLCPhases in the SDLC
1) Planning1) Planning2) Analysis2) Analysis3) Design3) Design4) Implementation4) Implementation5) Use5) Use
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The System Development LifeThe System Development LifeCycle (SDLC)Cycle (SDLC)
SDLC is the phrase that encompasses the planning,SDLC is the phrase that encompasses the planning,analysis, design, and implementation phases of the systemanalysis, design, and implementation phases of the systemlife cyclelife cycleWho participatesWho participates–– IS personnelIS personnel–– UserUser–– Information specialists can consultInformation specialists can consult
TraditionalTraditional–– Information specialists working with users.Information specialists working with users.–– A new strategy: OutsourcingA new strategy: Outsourcing
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Life Cycle ManagementLife Cycle Management
An upward migrationAn upward migrationExecutive responsibilityExecutive responsibilityMIS steering committeeMIS steering committee–– FunctionsFunctions
»» Set policySet policy»» Control the purse stringsControl the purse strings»» Resolve conflictsResolve conflicts
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Executives
MIS SteeringCommittee
Project leader -Warehouselocation model team
Project leaderMRP 11 team
Project leaderISDN system team
Project leader HRIS team
Marketing
Manufacturing
Finance
HumanResources
Project leaderCredit approvalsystem team
Managers of Systems Life Cycles are Arranged in a HierarchyManagers of Systems Life Cycles are Arranged in a Hierarchy
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Main Advantages ofMain Advantages ofthe Steering Committeethe Steering Committee
Total firm supportTotal firm supportProjects will be characterized by goodProjects will be characterized by goodplanning and controlplanning and controlEstablishes policies, provides fiscal control,Establishes policies, provides fiscal control,and resolves conflictsand resolves conflicts
Since the steering committee will probably not getinvolved with the details of the work, a projectteam is usually appointed.
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Planning PhasePlanning Phase
BenefitsBenefits–– Define scope of the projectDefine scope of the project
–– Spot potential problemsSpot potential problems
–– Arrange tasks in sequenceArrange tasks in sequence
–– Provide basis for controlProvide basis for control7-9
StepsSteps
1. Recognize problem (the trigger)1. Recognize problem (the trigger)2. Define problem2. Define problem3. Set objectives3. Set objectives4. Identify constraints4. Identify constraints
Recall that objectives, standards,and constraints are problem-solvingelements.
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Steps (cont.)Steps (cont.)
5.5. Conduct feasibility study (TENLOS)Conduct feasibility study (TENLOS)–– TechnicalTechnical–– Economic returnEconomic return–– Noneconomic returnNoneconomic return–– Legal and ethicalLegal and ethical–– OperationalOperational–– ScheduleSchedule
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Steps (cont.)Steps (cont.)
6.6. Prepare study project proposalPrepare study project proposal–– Goes to MIS steering committeeGoes to MIS steering committee
7.7. Approve or disapprove (go/no go)Approve or disapprove (go/no go)–– Key questions?Key questions?1.1.Will the system accomplish its goals?Will the system accomplish its goals?2.2.Is this the best way to go about it?Is this the best way to go about it?
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Steps (cont.)Steps (cont.)
8.8. Establish a control mechanismEstablish a control mechanism–– Think in terms of:Think in terms of:
»» 1. What1. What»» 2. Who2. Who»» 3. When (Person-months versus calendar months)3. When (Person-months versus calendar months)
–– PERT and CPM network diagramsPERT and CPM network diagrams
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Define theproblem
ConsultConsult
Prepare a systemstudy proposal
Establish a control mechanism
Approve or disapprove the study project
Recognize the problem
Set systemobjectives
Identify systemconstraints
The Planning PhaseThe Planning PhaseMIS SteeringMIS Steering Comm Comm Manager Systems AnalystManager Systems Analyst
1.1.
2.2.
3.3.
4.4.
5.
6.
7.7.
8.8.
Conduct afeasibility study
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Outline of a System Study ProposalOutline of a System Study Proposal1. Executive summary2. Introduction3. System objectives and constraints4. Possible system alternatives5. The recommended system study project
5.1 Tasks to be performed5.2 Human resource requirements5.3 Schedule of work5.4 Estimated cost
6. Expected impact of the system6.1 Impact on the firm’s organization structure6.2 Impact on the firm’s operations6.3 Impact on the firms resources
7. General development plan (analysis, design, and implementation phase)8. Summary
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A Project ScheduleA Project ScheduleFunctional System:Functional System: MarketingMarketingSubsystem:Subsystem: ProductProductModel:Model: Product DeletionProduct Deletion
SubtaskSubtaskTimeTime
EstimateEstimate(Person Months)(Person Months)
ResponsibilityResponsibility
1. Identify1. Identifydeletion criteriadeletion criteria
2. Identify output2. Identify outputinformationinformationrequirementsrequirements
Systems analystSystems analystProduct managerProduct manager
Systems analystSystems analystNetwork specialistNetwork specialistProduct managerProduct manager
0.750.75
0.250.257-16
Project Schedule (cont.)Project Schedule (cont.)
3. Identify input data Systems analyst 0.503. Identify input data Systems analyst 0.50 requirements DBA requirements DBA4. Prepare new system Systems analyst 2.004. Prepare new system Systems analyst 2.00 documentation documentation5. Design network Network specialist 1.505. Design network Network specialist 1.506. Design database DBA 0.506. Design database DBA 0.507. Review design Product manager 0.257. Review design Product manager 0.25 Systems analyst Systems analyst8. Prepare program Programmer 1.008. Prepare program Programmer 1.00 documentation documentation
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Project Schedule (cont.)Project Schedule (cont.)
9. Code program Programmer 1.259. Code program Programmer 1.2510. Test program Programmer 0.7510. Test program Programmer 0.75 Operations staff Operations staff11. Approve program Product manager 0.5011. Approve program Product manager 0.50 VP of marketing VP of marketing12. Prepare database DBA 2.0012. Prepare database DBA 2.0013. Educate users Systems analyst 0.5013. Educate users Systems analyst 0.5014. Cutover to model Operations staff 0.7514. Cutover to model Operations staff 0.75
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Analysis PhaseAnalysis Phase
StepsSteps1.1.AnnounceAnnounce
»» Reasons for projectReasons for project»» Purpose: inform and counteract fearPurpose: inform and counteract fear
2.2.Organize project teamOrganize project team»» User(s)User(s)»» SpecialistsSpecialists»» Define rolesDefine roles
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Analysis Phase (cont.)Analysis Phase (cont.)
3.3. Define information needsDefine information needs»» MethodsMethods
Personal interview (the preferred method)Personal interview (the preferred method)ObservationObservationRecord search (includes review of existingRecord search (includes review of existingdocumentation)documentation)SurveysSurveys
A project directory can bemaintained as an encompassing setof documentation to describe thesystem
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Analysis Phase (cont.)Analysis Phase (cont.)
4.4. Define system performance criteriaDefine system performance criteria5.5. Prepare design proposalPrepare design proposal(Compare to system study proposal)(Compare to system study proposal)6.6. Approve or disapprove the designApprove or disapprove the design
projectproject
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Announce the system study
Organize the project team
Define information needs
Define system performance criteria
Preparedesign
proposal
Approve or disapprove the design project
1.
2.
3.
4.
5.
6.
The Analysis PhaseThe Analysis PhaseMIS SteeringMIS SteeringCommitteeCommittee ManagerManager Systems AnalystSystems Analyst
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Outline of a Design ProposalOutline of a Design Proposal1. Executive summary2. Introduction3. Problem definition4. System objectives and constraints5. Performance criteria6. Possible system alternatives7. The recommended design project
7.1 Tasks to be performed7.2 Human resource requirements7.3 Schedule of work7.4 Estimated cost
8. Expected impact of the system8.1 Impact on the firm’s organization structure8.2 Impact on the firm’s operations8.3 Impact on the firms resources
9. General development plan (analysis, design, and implementation)10. Summary
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Approve or disapprove the systemApprove or disapprove the systemimplementationimplementation
Prepare thePrepare thedetaileddetaileddesigndesignsystemsystem
IdentifyIdentifyalternatealternatesystemsystem
configurationsconfigurations
EvaluateEvaluatesystemsystem
configurationsconfigurations
Select theSelect thebestbest
configurationconfiguration
Prepare thePrepare theimplementationimplementation
proposalproposal
1.1.
2.2.
3.3.
4.4.
5.5.
6.
MIS Steering CommitteeMIS Steering Committee ManagerManager Systems AnalystSystems Analyst
The Design PhaseThe Design Phase
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Design PhaseDesign Phase
1.1. Prepare detailed designPrepare detailed design–– Structured design (top down)Structured design (top down)
»» System levelSystem level»» Subsystem levelSubsystem level
–– Documentation toolsDocumentation tools
2. Identify alternate system configurations2. Identify alternate system configurations–– Refine to a manageable setRefine to a manageable set
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Popular Documentation ToolsPopular Documentation Tools
Data Modeling Entity-relationship diagramData dictionaryScreen/printer layout form
Process Modeling System flowchartProgram flowchartData flow diagramStructured English
Object Modeling Object relationship modelClass specification
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Data Flow Diagram of Four Data Processing SubsystemsData Flow Diagram of Four Data Processing Subsystems
Customers
1.4Accounts
Receivable
1.1OrderEntry
1.3Billing
1.2Inventory
Sales orders
Rejected salesorder notices
Accepted orders
Payments bycustomers
Stat
emen
ts
Invoices
Billed orders
Receivables ledger data
Order logremovals file
Filled items
Inventoryledger data
Received items
Purchasing data
3
3 2
2
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Data Flow Diagram of Order Entry SystemData Flow Diagram of Order Entry SystemSales orderedit rejects
Order log
Sales ordercredit rejects
Customercredit file
Customer
1.1.1Edit
orderdata
1.1.2Compute
creditcheck
1.1.3Log inorders
1.1.4Markfilled
orders
1.2
1.3
Sales orders Edit rejects
Rejectedsales ordernotices
Edited orders
Credit data
Edited and checked orders
Credit rejects
Acceptedorders
Completed orders Date filled
Order data
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Hardware Choices Make PossibleHardware Choices Make PossibleMultiple System ConfigurationsMultiple System Configurations
System ElementsSystem Elements AlternativesAlternatives••CRT terminalCRT terminal••Hardcopy terminalHardcopy terminal••OCROCR
Input
Order log
Customer credit file
Rejected orders file
Accepted orders file
Completed orders file
Rejected orders notice
Processing
••Magnetic tapeMagnetic tape••DASDDASD
••Magnetic tapeMagnetic tape••DASDDASD
••Magnetic tapeMagnetic tape••DASDDASD
••Magnetic tapeMagnetic tape••DASDDASD
••Magnetic tapeMagnetic tape••DASDDASD
••PrinterPrinter••CRT terminalCRT terminal••Hardcopy terminalHardcopy terminal••BatchBatch
••OnlineOnline
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Alternatives Selected for Detailed StudyAlternatives Selected for Detailed StudyAlternativeAlternative
InputInputOrderOrderLogLog
CustomerCustomerCredit FileCredit File
Accepted &Accepted &RejectedRejected
Orders FileOrders File
CompletedCompletedOrders FileOrders File
RejectedRejectedOrdersOrdersNoticeNotice
1.1.
2.2.
3.3.
ScannerScanner
KeyboardKeyboardterminalterminal
MagneticMagnetictapetape
KeyboardKeyboardterminalterminal
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
MagneticMagnetictapetape
PrinterPrinter
PrinterPrinter
HardcopyHardcopyterminalterminal
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Design Phase (cont.)Design Phase (cont.)
3. Evaluate configurations3. Evaluate configurations4. Select best configuration4. Select best configuration5. Prepare implementation proposal5. Prepare implementation proposal6. Approve or disapprove the system6. Approve or disapprove the system
implementationimplementation
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1. Executive summary2. Introduction3. Problem definition4. System objectives and constraints5. Performance criteria6. System design
6.1 Summary description6.2 Equipment configuration
7. The recommended implementation project7.1 Tasks to be performed7.2 Human resource requirements7.3 Schedule of work7.4 Estimated cost
8. Expected impact of the system8.1 Impact on the firm’s organization structure8.2 Impact on the firm’s operations8.3 Impact on the firms resources
9. General implementation plan10. Summary
Outline of an Implementation ProposalOutline of an Implementation Proposal
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Implementation PhaseImplementation Phase
Acquire and integrate the physical andAcquire and integrate the physical andconceptual resources to produce aconceptual resources to produce aworking systemworking system
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Steps for the Implementation PhaseSteps for the Implementation Phase1. Plan implementation2. Announce3. Obtain hardware resources
RFP / Written Proposals4. Obtain software resources
"Make or buy"5. Prepare database6. Prepare physical facilities7. Educate participants and users8. Prepare cutover proposal9. Approve or disapprove cutover to new systsem10. Cutover to new system
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Plan the implementation
Announce the implementation
Control
Cutover the new system
Obtain the hardware resources
Obtain the softwareresources
Prepare the database
Educate the participants and users
Prepare the physical facilities
Control
1.1.
2.2.33
44
55
66
77
8.
The Implementation PhaseThe Implementation PhaseMIS Steering CommitteeMIS Steering Committee ManagerManager Information SpecialistsInformation Specialists
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Outline of a Request for ProposalOutline of a Request for Proposal
1. Letter of transmittal2. System objective and applicable constraints3. System design
3.1 Summary description3.2 Performance criteria3.3 Equipment configuration3.4 Summary system documentation3.5 Estimated transaction volume3.6 Estimated file size
4. Installation schedule
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Outline of Supplier ProposalOutline of Supplier Proposal
1. Letter of transmittal2. Summary of recommendations3. Advantages4. Equipment configuration5. Equipment specifications
5.1 Performance data5.2 Prices
6. Satisfaction and performance criteria7. Delivery schedule
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Cutover ApproachesCutover Approaches
Old System
Old System New System
Immediate cutoverPhased cutover
Parallel cutover
Pilot System
Immediate
Old SystemNew SystemPhased
New system
Old SystemParallel
Time
Pilot
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Use PhaseUse Phase1.1.UseUse2.2.Audit (post implementation review)Audit (post implementation review)
»» By information specialist(s)By information specialist(s)»» By internal auditor (a different one from theBy internal auditor (a different one from the
project team member)project team member)
3. Maintain the system3. Maintain the system»» Correct errorsCorrect errors»» Keep currentKeep current»» ImproveImprove
4. Prepare reengineering proposal4. Prepare reengineering proposal5. Approve or disapprove reengineering5. Approve or disapprove reengineering
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The Use PhaseThe Use Phase
Control Use thesystem
Audit thesystem
Maintain the
system
Preparere-
engineeringproposal
Approve or disapprove thereengineering proposal
MIS Steering Committee Manager Information Specialists
12
3
4
5
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PrototypingPrototyping
Type I -- Becomes operational systemType I -- Becomes operational system
Type II -- Serves as a blueprintType II -- Serves as a blueprint
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Development of a Type I PrototypeDevelopment of a Type I Prototype
1.1.
2.2.
3.3.
4.4.
NN
Identify user needsIdentify user needs
Develop a prototypeDevelop a prototype
PrototypePrototypeacceptable?acceptable?
YY
Use the prototypeUse the prototype
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DevelopmentDevelopmentof a Type IIof a Type IIPrototypePrototype NN
NN
Identify userIdentify userneedsneeds
Develop aDevelop aprototypeprototype
Code theCode theoperational systemoperational system
Test theTest theoperational systemoperational system
Use theUse theoperational systemoperational system
PrototypePrototypeacceptable?acceptable?
SystemSystemacceptable?acceptable?
YY
YY
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The Attraction of PrototypingThe Attraction of PrototypingCommunications between the systemsCommunications between the systemsanalyst and user are improved.analyst and user are improved.The analyst can do a better job ofThe analyst can do a better job ofdetermining the user’s needs.determining the user’s needs.The user plays a more active role in systemThe user plays a more active role in systemdevelopment.development.The information specialists and the userThe information specialists and the userspend less time and effort in developing thespend less time and effort in developing thesystem.system.Implementation is much easier because theImplementation is much easier because theuser knows what to expect.user knows what to expect. 7-44
Potential Pitfalls of PrototypingPotential Pitfalls of PrototypingThe haste to deliver the prototype mayThe haste to deliver the prototype mayproduce shortcuts in problem definition,produce shortcuts in problem definition,alternative evaluation, and documentation.alternative evaluation, and documentation.The users may get so exited about theThe users may get so exited about theprototype that they have unrealisticprototype that they have unrealisticexpectations of the operational system.expectations of the operational system.Type I prototypes might not be as efficientType I prototypes might not be as efficientas systems coded in a programmingas systems coded in a programminglanguage.language.The computer-human interface provided byThe computer-human interface provided bycertain prototyping tools may not reflectcertain prototyping tools may not reflectgood design techniques.good design techniques. 7-45
Applications That Are GoodApplications That Are GoodProspects for PrototypingProspects for PrototypingHigh riskHigh riskConsiderable user interactionConsiderable user interactionLarge number of usersLarge number of usersA need for quick deliveryA need for quick deliveryAn expected short use phase of theAn expected short use phase of thesystemsystemAn innovative systemAn innovative systemUnpredictable user behaviorUnpredictable user behavior
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Rapid Application Development (RAD)Rapid Application Development (RAD)
Information engineering (IE)Information engineering (IE)Key ingredientsKey ingredients–– Management should be experimenters orManagement should be experimenters or
early adaptersearly adapters–– Specialized teamsSpecialized teams–– Methodologies (RAD life cycle)Methodologies (RAD life cycle)–– Tools (I-CASE, 4GLs)Tools (I-CASE, 4GLs)
RAD and the SLC are applications of theRAD and the SLC are applications of thesystems approachsystems approachTools are mainly 4th generation languages andTools are mainly 4th generation languages andCASE toolsCASE tools 7-47
Informationstrategyplanning
(ISP)Business area
analysis(BAA)
Rapid application development(RAD)
.
Strategic overview of theinformation needed to runan enterprise as efficientlyas possible
Data model
Design of records used by specificprocedures
Strategic overview of thefunctions and goals ofan enterprise
The process needed tooperate the enterpriseand how they interrelate
Design ofprocedures forspecific applications
Rapid Application Development is an Integral Part of Information Engineering
DataActivities
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Business Process RedesignBusiness Process Redesign(BPR)(BPR)
Often used to react to systems that can noOften used to react to systems that can nolonger function adequately in the currentlonger function adequately in the currentbusiness environment of the firm (legacybusiness environment of the firm (legacysystems fall into this category)systems fall into this category)Three techniques for business processThree techniques for business processredesign areredesign are1) reverse engineering1) reverse engineering2) restructuring2) restructuring3) reengineering3) reengineering 7-49
Reverse EngineeringReverse EngineeringReverse Engineering Produces Documentation onReverse Engineering Produces Documentation onSuccessively Higher Levels but Leaves the SystemSuccessively Higher Levels but Leaves the System
UnchangedUnchanged
ReverseReverseEngineeringEngineering EngineeringEngineering
ReverseReverseEngineeringEngineeringReverseReverse
EngineeringEngineeringReverseReverse
Planning Planning PhasePhase
Analysis Analysis PhasePhase
Design Design PhasePhase
ImplementationImplementationPhasePhase
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RestructuringRestructuring
PlanningPhase
Restructuring Restructuring Restructuring Restructuring
AnalysisPhase
DesignPhase
ImplementationPhase
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ReengineeringReengineeringReverseEngineering
ReverseEngineering
ReverseEngineering
ReverseEngineering
ForwardEngineering
ForwardEngineering
ForwardEngineering
ForwardEngineering
Planning Phase
Analysis Phase
DesignPhase
ImplementationPhase
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Selection of BPR ComponentsSelection of BPR Components
Based upon functional qualityBased upon functional quality–– What the system doesWhat the system does
Based upon technical qualityBased upon technical quality–– How the system does its jobHow the system does its job
The relationship between these twoThe relationship between these twocharacteristics suggest which BPRcharacteristics suggest which BPRtechnique would be appropriatetechnique would be appropriate
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FunctionalQuality(What?)
Good
Technical Quality(How?)
Poor
Poor
Good
Selection of BPR Components
Reverse Engineer
Restructure
Do Nothing
ForwardEngineer
Reengineer
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SLC, Prototyping, RAD, and BPR inSLC, Prototyping, RAD, and BPR inPerspectivePerspective
SLC, prototyping, and RAD are allSLC, prototyping, and RAD are allmethodologiesmethodologies–– Recommended ways of implementing aRecommended ways of implementing a
computer-based systemcomputer-based system
BPR revamps systems that wereBPR revamps systems that wereimplemented with computer technology thatimplemented with computer technology thathas become obsoletehas become obsolete
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SummarySummary
System Life CycleSystem Life Cycle–– PlanningPlanning–– AnalysisAnalysis–– DesignDesign–– ImplementationImplementation–– UseUse
Cycle management responsibilityCycle management responsibilityOther methodologiesOther methodologies
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