tailieunhanh - Chương 8: Modeling System Objectives with Goal Diagrams

Prescriptive statements of intent the system should satisfy through cooperation of its agents. | Building System Models for RE Chapter 8 Modeling System Objectives with Goal Diagrams Intentional view of the modeled system : Goals : Risks : Conceptual objects : Agents on what? why ? who ? Goals as seen in Chapter 7 Prescriptive statements of intent the system should satisfy through cooperation of its agents formulated in terms of problem world phenomena at various levels of abstraction/granularity Can be negotiated, weakened, prioritized (unlike domain props) The finer-grained a goal, the fewer agents required for its satisfaction requirements, expectations: single-agent goals Behavioral (Achieve/Maintain) goals, soft goals Functional, quality, development goals A goal model shows contribution links and leafgoal assignments AND-refinement OR- refinement Goal modeling: outline Goal features as model annotations Goal refinement Capturing conflicts among goals Connecting the goal model with other system views Capturing alternative options Goal diagrams as AND/OR graphs Documenting goal refinements & assignments with annotations Building goal models: heuristic rules & reusable patterns Goal features are specified in model annotations Goal Maintain [DoorsClosedWhileMoving] Def All train doors shall be kept closed at any time when the train is moving [ FormalSpec . in temporal logic for analysis, not in this chapter . ] [ Category Safety ] [ Priority Highest ] [ Source From interview with railway engineer X . ] DoorsClosedWhileMoving precise definition goal features annotation Goal refinement An AND-refinement of goal G into subgoals G1, ., Gn states that G can be satisfied by satisfying G1, ., Gn The set {G1, ., Gn} is called refinement of G Subgoal Gi is said to contribute positively to G Achieve [BookRequestSatisfied] Achieve [ CopyBorrowed If Available] Achieve [CopyDueSoon If Not Available] Def In case a requested book has no copy available for check out, a copy of that book shall be made available within 2 weeks for check | Building System Models for RE Chapter 8 Modeling System Objectives with Goal Diagrams Intentional view of the modeled system : Goals : Risks : Conceptual objects : Agents on what? why ? who ? Goals as seen in Chapter 7 Prescriptive statements of intent the system should satisfy through cooperation of its agents formulated in terms of problem world phenomena at various levels of abstraction/granularity Can be negotiated, weakened, prioritized (unlike domain props) The finer-grained a goal, the fewer agents required for its satisfaction requirements, expectations: single-agent goals Behavioral (Achieve/Maintain) goals, soft goals Functional, quality, development goals A goal model shows contribution links and leafgoal assignments AND-refinement OR- refinement Goal modeling: outline Goal features as model annotations Goal refinement Capturing conflicts among goals Connecting the goal model with other system views Capturing alternative options Goal diagrams as .