Information Technology IMS5024 Information Systems Modelling Blum’s Taxonomy

School of Information Management & Systems 12.2 Content re-visit the taxonomy application to the methods

School of Information Management & Systems 12.3 Why create models? to communicate to represent to explain to clarify to simplify to contextualise to record

School of Information Management & Systems 12.4 Software development analysis design implementation

School of Information Management & Systems 12.5 Taxonomy of methods “…there will be few invariants in the domain of design methods.”

School of Information Management & Systems 12.6 Domains of modelling business occurs in the application domain what people do what management wants how results are interpreted models of the application domain correspond to the described need are valid solutions to a problem

School of Information Management & Systems 12.7 Domains of modelling software development occurs in the implementation domain demonstrably correct logically precise technologically operable models in the implementation domain correct in terms of instrumental technology verifiable against formal criteria

School of Information Management & Systems 12.8 The software process Implementation domain Conceptual model Formal model Application domain

School of Information Management & Systems 12.9 Correspondence for any identified business need there may be many conceptual models for each conceptual model, many formal models are possible for each formal model there may be many correct implementations There is no formal way of defining the “best” response

School of Information Management & Systems Openness business problems are Open some requirements are considered implicit software products are Closed the delivered functionality is explicit scope for mismatch

School of Information Management & Systems A framework of methods problem oriented or product oriented conceptual or formal (this is Blum’s framework – there are sure to be other, different views)

School of Information Management & Systems Blum’s framework Problem oriented Product oriented ConceptualIII FormalIIIIV after Blum, p86

School of Information Management & Systems Blum’s classification of design methods Problem oriented Product oriented Conceptual I Structured Analysis Entity-Relationship model Logical construction of sys Modern Structured Anal Object-oriented analysis II Structured design Object-oriented design Formal III PSL/PSA JSD VDM IV Levels of abstraction stepwise refinement Proof of correctness data abstraction JSP Object-oriented programming after Blum, p92

School of Information Management & Systems Reference Blum, B.I. (1994) A taxonomy of software development methods. Communications of the ACM, 37, 11, pp