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Systems Development Approach. Topics. Frames. Development Approach. Matching Classification . XP. SSADM. Long Running Transaction. SE. Technology. Modelling. Server Scripting. Statechart. Sequence Diagram. SQL & RDBMS. EER. Web services. XML. Use Case. Matching (again).
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Topics Frames Development Approach Matching Classification XP SSADM Long Running Transaction SE Technology Modelling Server Scripting Statechart Sequence Diagram SQL & RDBMS EER Web services XML Use Case
Matching (again) • Generally, matching means to ends • Donor to patient • Documents to a search query • … Easier to assess But depends on modelling Model of Means Model of ends Means Ends Fitness required but hard to assess
Matching in Systems Development • Technology to Application • Internet Technology (Php/MySQL, J2EE,.NET • To • Given implementation problem
Matching in Systems Development Approaches • Current Development models • SSADM • XP • SE&A • To • Specific Application and Organisational Context
Matching by factor weightingclassical approach • E.g. Spam/Ham • E.g. Selecting a host for a web site • A. Model all hosts as a set of factors • Cost • Functionality • PHP • SQL.. • Filestore limit in Mb • Bandwidth Mb/month • B. For a given problem, select weights for importance of each factor • C. Calculate the weighted sum of factors • D. Choose the host with the highest score.
Matching by prototype • E.g. Selecting a Development approach • Would factor weighting work? • Alternative is prototype based: • Identify typical situations in which each approach has been successful • Assess how ‘close’ each situation is the those typical situations • Use weightings to measure closeness
IBM paper • Version 1 • – complex set of stakeholders • Good framework for processes of project management and software development • Little formality in stakeholder and system requirements => changing requirements, lost functionality
Version 2 – adopt Systems Engineering and Architecture approach • Clear distinction between stakeholder and system requirements • Understandable and unambiguous requirements • Stakeholder ownership • Requirements database
Benefits of SE & A • Definition of Mission Critical requirements • Making schedule a critical mission requirement • Intimate stakeholder involvement throughout • Traceability • Structure baseline change control • Scored Reviews
XP v SSADM v SE&A • Review the 12 practices of XP • Read the paper • Read the DSDM XP paper • Tutorial discussion on selection of development approach