Systematic Elicitation of Mode Models for Multifunctional Systems

I held this talk at the 2015 IEEE International Requirements Conference in Ottawa, Canada

Transcript

1. Systematic Elicitation of Mode Models for Multifunctional Systems RE 2015, Ottawa, Canada August 26, 2015 Andreas Vogelsang, Henning Femmer Institut für Informatik Technische Universität München Christian Winkler MAN Truck & Bus AG Munich, Germany
2. Modes in Requirements Engineering 2 “The air conditioning must maintain the desired temperature if the engine is running.” FKN1 FKN2 FKN3 FKN4 FZGFKN1 FZGFKN2 What does “engine running” in this case exactly mean? What happens in case of start/stop? We need a model of modes within a system! Precise definitions Source for requirements Tracing
3. Mode Models and Description Techniques • Mode model = (structured) set of modes • Representation as statechart: 3 mode category mode value mode AND decomposition XOR decomposition
4. Systematic Elicitation of Mode Models 4 Textual Requirements (Inspection) Domain Knowledge (Interviews) FKN1 FKN2 FKN3 FKN4 FZGFKN1 FZGFKN2 System Architecture (Dependency Analysis)
5. Study Design and Context • Research questions: – RQ1: Are the introduced elicitation approaches feasible in practice? – RQ2: Are the resulting mode models manageable? – RQ3: How do the elicited modes differ? • Data Collection: 5 FKN1 FKN2 FKN3 FKN4 FZGFKN1 FZGFKN2 Elicitation Mode Model Assessment / / RQ1 RQ2 RQ3 Discussion of RQs
6. Elicitation by Interviews with Domain Experts General idea: Experts know the modes within their application domain 6 4 interviews: • cabin & lights • base software • energy management • driver assistance
7. Elicitation by Requirements Inspection General idea: Requirements often implicitly contain statements about modes 7 11 requirements specifications 223 requirements The air conditioning must maintain the desired temperature if the engine is running. The air conditioning must maintain the desired temperature if the engine is running. The air conditioning must maintain the desired temperature if the engine is running.
8. Window Lifter Airbag Cruise Control … Elicitation by Feature Dependency Analysis General idea: Relation between feature dependencies and modes [1,2] 8 Transfer signal to a mode: Check data type: • Boolean  Signal transferred to mode with values yes/no • Enumeration  Signal transferred to mode with values of enumeration • Value  Check requirements document for discrete description of signal [1] M. Broy: Multifunctional software systems: Structured modeling and specification of functional requirements. 2010 [2] D. Dietrich, J.M. Atlee: A mode-based pattern for feature requirements, and a generic feature interface. RE’13 FKN1 FKN2 FKN3 FKN4 FZGFKN1 FZGFKN2
9. Assessment of Resulting Mode Models 9 RQ1: Are the introduced elicitation approaches feasible in practice? RQ2: Are the resulting mode models manageable? RQ3: How do the elicited modes differ? Number of Modes (NM) Nesting Depth (ND) Number of Mode Values (NMV) Scope of Modes (Context, System, Feature) structural measures qualitative measure
10. Study Results: Elicited Mode Models 10 FKN1 FKN2 FKN3 FKN4 FZGFKN1 FZGFKN2
11. Study Results: Discussion of RQs 11 Research Questions: • RQ1: Are the introduced elicitation approaches feasible in practice? • RQ2: Are the resulting mode models manageable? • RQ3: How do the elicited modes differ? FKN1 FKN2 FKN3 FKN4 FZGFKN1 FZGFKN2
12. Reference Mode Model for MAN • Number of modes: 75 modes in 15 mode categories • Number and overlap of elicited modes: 12 FW: MAN wants to adopt the reference mode model in their development process FKN1 FKN2 FKN3 FKN4 FZGFKN1 FZGFKN2
13. Summary Thank you. Elicitation Approaches Modes in RE Empirical Assessment Take away message: Eliciting mode models is feasible in practice; A combination of our elicitation approaches yields a comprehensive model of operational states. @andivogelsang vogelsan@in.tum.de