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Systems DevelopmentMBA 8125 – Week 8
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CorporateStrategy
ISStrategyand Plan
InternalSystems
Development
OutsourcedSystems
Development
Implementation
InternalSystems
Operations
OutsourcedSystems
Operations
Infrastructure
Security
Course Overview
OrganizationalDesign
Strategy
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Learning Objectives
Describe the systems development life cycle Apply project management principles to information
systems projects Understand the user’s role in the development and
implementation of information systems Identify generic system conversion strategies Examine challenges to structured stable-state thinking Understand that security starts with development
efforts.
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Challenges & Questions
Can building new systems produce organizationalchange? Should it?
How can a company can information systems thatfit its business plan?
What are the core activities in the systemsdevelopment process?
What are the alternative methods for buildinginformation systems?
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Agenda
Software Engineering Systems Development Life Cycle Alternative Methodologies
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“The study of methods for producing high quality software atminimum cost.”
Stakeholders: Users, managers, designers, programmers,competitors.
Issues: Efficiency, quality, delivery target, changingrequirements, innovation, team interaction, team incentives,project organization and management, software structure,reusability, prototyping, formal description techniques,development tools.
What is Software Engineering
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Why Develop an Information System?
Phenomena that trigger IS development An opportunity (proactive) A problem (reactive) A directive
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Ultimate Management Challenge
“... It’s hard work to make improvementswithout changing anything...”
Mikahail Gorbachev, from his address to theSupreme Soviet Congress, February, 1986
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System Interdependence
BusinessStrategy
Rules
Processes
Figure 1.2 (Laudon & Laudon 2006)
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Definition of Success
“A successful software project is one whosedeliverables satisfy and possibly exceed thestakeholders’ expectations, that is developed in atimely and economical fashion, and is resilient tochange and adaptation.”(adapted from Grady Booch and others) On time Within budget Meet expectations Adaptable (Why is this important?)
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Agenda
Software Engineering Systems Development Life Cycle Alternative Methodologies Managing Software Projects Security
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Systems Development Life Cycle
Planning/ definition
Study/analysis
Design
Programming
Installation
Maintenance
STAGES
Project proposal reportSystem proposal report
Design specificationsProgram code
Testing and installation
Postimplementation audit
END PRODUCTS
OPERATIONSMilestone 1
Project initiation
Milestone 2Designsolutiondecision
Milestone 3 Designspecification sign-off
Milestone 4 Productiondecision
Year 1Year 2 3-8 year lifespan
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Spiral (Iterative) Model
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Initial Project RisksInitial Project Scope
Revise OverallProject Plan• Cost• Schedule• Scope/Content
Plan Iteration N• Cost• Schedule
Assess Iteration N
Risks EliminatedRevise Project Risks• Reprioritize
Develop Iteration N• Collect cost andquality metrics
Define scenariosto address highestrisks
Iteration N
Iterations Retire Risks
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“Make sure thesystem works!”
Importance of Testing
Unit Test Integration Test Full System Test Stress Testing Field Testing Regression Testing
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Strategies usedto convert fromone IS to another
Installation: Conversion Strategies
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Activities in Systems Support
Maintenance and Support
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Agenda
Software Engineering Systems Development Life Cycle Alternative Methodologies Managing Software Projects Security
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Alternative Methodologies
Other options for software development: Rapid Prototyping Iterative Development Object-Oriented Development “Off the Shelf” Applications End User Development Outsourcing
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Build experimental system to demonstrate, evaluateapproach; users refine needs
Prototype: Preliminary working version of informationsystem for demonstration, evaluation purposes
Problems: Omission of basic requirements.
Lack of documentation, testing.
Prototyping tools may not be capable of developing complexsystems.
Users see prototype and expect to be able to use it.
Alternative Methodologies:Rapid Prototyping
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Prototyping Guidelines
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In iterative development, refinement of the system continues until usersare satisfied.
Alternative Methodologies:Iterative Development
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• Object• basic unit of systems analysis and design• important entities (“things”)
• (e.g. customer, account, product, sale,invoice, employee, etc.)
• combine data and processes used on the data(e.g. sale may have a process or method calledcalculate_total and account may haveupdate_balance as a method)
Object-Oriented Development
Source: Laudon & Laudon 2006
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Class and Inheritance
Figure 14-9Source: Laudon & Laudon 2006
Class Name
Attributes (data)
Methods (processes)
SubClass Name
More attributes
More methods
See http://www.agilemodeling.com/style/classDiagram.htm
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• Industry standard for representing variousviews of an object-oriented system using aseries of graphical diagrams
• Diagrams
Unified Modeling Language (UML)
1. Structural diagrams: relationship betweenclasses
2. Behavioral diagrams: interactions inobject-oriented system
Source: Laudon & Laudon 2006
See http://www.agilemodeling.com/essays/umlDiagrams.htm
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A UML Use Case Diagram
Figure 14-10Source: Laudon & Laudon 2006
See http://www.agilemodeling.com/style/useCaseDiagram.htm
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Alternative Methodologies:End-User Development
End-users develop system with little help from technicalspecialists Small, desktop applications Users have autonomy over system
Management Benefits Improved requirements Development controlled by users Reduced application backlog
Management Problems Insufficient review / analysis Lack of standards and controls Proliferation of “private” information systems and data
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Alternative Methodology:Acquiring Software Packages
Commercial Off theShelf (COTS)Packages Set of prewritten
application softwareprograms commerciallyavailable
Modification ofsoftware package tomeet organization’sneeds
Figure 14.12 – Laudon & Laudon 2006
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Purchase of an externally produced good orservice that was previously produced internally
Alternative Methodology:Outsourcing
AdvantagesEconomyPredictabilityFrees up human resources
DisadvantagesLoss of controlVulnerability of strategic informationDependency
Is Outsourcing Fool’s Gold? (Kroenke, 2006)
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Comparison of Systems Development Approaches
Can lead to proliferation ofuncontrolled informationsystemsSystems do not always meetquality assurance standards
Users control systems-buildingSaves development timeand costReduces applicationbacklog
Systems created by endusers using fourth-generation softwaretoolsRapid and informalMinimal role of IT dept
End-user Development
Inappropriate for large, complexsystemsCan gloss over steps in analysis,documentation, and testing
Rapid and inexpensiveUseful whenrequirements areuncertain or when end-user interface isimportantPromotes userparticipation
Requirements specifieddynamically withexperimental system
Rapid, informal, anditerative process
User interacts withprototype
Prototyping
Slow and expensiveDiscourages changesMassive paperwork to manage
Necessary for largecomplex systemsand projects
Sequential step-by-stepprocess
Written specificationand approvals
Limited role of users
Systems Lifecycle(Waterfall)
Approach Features Advantages Disadvantages
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May not meetorganization’s uniquerequirementsMay not perform manybusiness function wellExtensive customizationraises development costs
Design, programming,installation, and maintenancework reducedCan save time and cost whendeveloping commonbusiness applicationsReduces need for internalinformation systemsresources
Commercial softwareeliminates need forinternally developedsoftware programs
Application Software Package
Loss of control over theinformation systemsfunctionDependence on thetechnical direction andprosperity of externalvendors
Can reduce or control costsCan produce systems wheninternal resources notavailable or technicallydeficient
Systems built andsometimes operated byexternal vendors
Outsourcing
Comparison of Systems Development Approaches
Approach Features Advantages Disadvantages
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• Changing demands in application development indigital firm era.
• Agility and scalability critical goals and successfactors. Strategic agility (innovation) organization mustdesign itself to be appropriately agile in response toexternal and internal forces (Gardner, 2004)
• Interorganizational system requirements whennetworks of applications are managed by differentbusiness partners
Evolving Challenges and SolutionsManagement Challenges
Source: Laudon & Laudon 2006
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Evolving Challenges and SolutionsEvolving Solutions
• Building systems by assembling and integrating existingsoftware components
Component-Based Development:
• Web services –tools to build new applications or enhancingexisting systems.
• Web services -- software components deliverable overInternet; provide functions for organization’s existing systemsor create new systems that link organization’s systems tothose of other organizations.
Web Services and Service-Oriented Computing:
Source: Laudon & Laudon 2006
See http://en.wikipedia.org/wiki/Service-oriented_architecture
See http://en.wikipedia.org/wiki/Web_service
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Duane Truex,
Richard Baskerville, & Heinz Klein
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Revoking Traditional ISD Goals
Lengthy analysis & design are poorinvestments
User satisfaction is improbable Abstract requirements are largely imaginary Complete and unambiguous specifications are
ineffectual New systems development projects denote
failure
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Emergent Goals
Always analysis Dynamic requirement negotiations Incomplete and usefully ambiguous
specifications Continuous redevelopment Adaptability orientation
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Figure . Alternative lifespan economies.(from Truex et al, 1999, CACM
Traditional
view
Emergent &
Deferred
view
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Supported by…
Back channel communications Emergent IT organizations Proper awards systems
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EmergentISD: Goals
andTechniques
(from Truex et al,CACM, 1999)
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Architectural Evolution
Standalonesystems
AdaptivePatchwork
DataWarehousing
TechnicalConnectivity
EnterpriseIntegration
ComponentArchitecture
Technologicalintegration
Dataintegration
Processintegration
Source: Dr. Stefano GrazioliUniversity of VirginiaUsed with permission
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Conclusions
Software engineering is challenging process Non-IS managers have important role in
software development Multiple methodologies for developing
software Information systems differ No development process works in all situations
Difficult to manage software projects
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