lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons 1 Part 2: Building System Models for RE Introduction

2 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons RE activities require focus and structure A recurrent problem... –focusing, structuring elicitation sessions & artefacts (Chap.2) –identifying items at common level of granularity for comparison, evaluation (Chap.3) –structuring large, complex specifications (Chap.4) –focusing inspection, validation, verification on structured specs (Chap.5) –identifying change units, granularities of traceable items, derivation links for reqs evolution (Chap.6)  Model-driven  Model-driven approach to RE

3 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons Model-Driven RE  Model: –abstract representation of system (as-is or to-be) –highlights, specifies, inter-relates key system features  Multi-view  Multi-view model: –different system facets for requirements completeness

4 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons Why models for RE ? key aspects  Focus on key aspects (abstraction from multiple details) structure  Provides structure for RE activities –target for what must be elicited, evaluated, specified, consolidated, modified –interface among RE activities: produce/consume model items analysis  Facilitates analysis –support for early detection and fix of errors  Support for understanding, explanation to stakeholders  Basis for making decisions –multiple options made explicit  Basis for generating the requirements document (with tool)

5 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons A goal-oriented approach to model-driven RE modeling generation of RE deliverables interviewsdocuments.html.rtf.pdf.mif existing systems analysis

6 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons techniques  Concentrates on solid, replicable RE techniques construction,  Emphasizes model construction, beyond mere use of diagrammatic notations –heuristic rules, tactics, modeling patterns, bad smells –UML compliance wherever possible UMLUnified Modeling Language, de facto standards Specific diagrams when not supported by UML ( e.g. goals)  Based on case studies in a variety of domains The lectures will summarize book chapters, see details there !

7 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons What models for RE ? why ? Goals Goals (Chap. 7, 8)

8 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons What models for RE ? Risks Risks (Chap.9) why ? 8 Goals (Chap. 7, 8)

9 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons What models for RE ? Conceptual objects Conceptual objects (Chap.10) on what? why ? Risks (Chap.9) Goals (Chap. 7, 8)

10 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons What models for RE ? Agents Agents (Chap.11) on what? why ? who ? Goals (Chap. 7, 8) Risks (Chap.9) Conceptual objects (Chap.10)

11 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons What models for RE ? Operations Operations (Chap.12) what ?

12 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons What models for RE ? what ? Behaviors - Scenarios Scenarios (Chap.13) Behaviors - State machines State machines (Chap.13) Operations (Chap.12)

13 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons What models for RE ? what ? I    Threats Threats (Chap. 16) Operations (Chap.12) Behaviors - Scenarios (Chap.13) Behaviors - State machines (Chap.13)

14 lamsweerde Part 2: Building System Models for RE © 2009 John Wiley and Sons Building system models for RE : more detailed outline Chap.8: Modeling system objectives with goal diagrams Chap.9: Risk analysis on goal models Chap.10: Modeling conceptual objects with class diagrams Chap.11: Modeling system agents and responsibilities Chap.12: Modeling system operations Chap.13: Modeling system behaviors: scenarios and state machines Integrating multiple system views Chap.14: Integrating multiple system views A Goal-oriented model building method in action Chap.15: A Goal-oriented model building method in action