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| Annex 1 | |||
| 5.8 Category of Methods "System Behavior Models" (SBM) |
SVM - Systemverhaltensmodelle
5.8.1 Overview
In the Methods Standard, the category of methods System Behavior Models is intended to support the requirement analysis of functional or software portions with high criticality. The support is realized on the levels System, Segment, and SW Unit, when complex real-time behavior occurs, having a great impact on the warranty of the functionality. A special method is only selected within the scope of the operationalization of the Method Standard.
5.8.1.1 Appraisal Criteria
Each individual method of the category SBM must at least have the following characteristics and features in order to be applied for the previously mentioned purpose:- notation of events, states, or elements of comparable meaning,
- representation of static causal connections between events and states (causal logic),
- representation of concurrent/parallel events/states,
- additional representation of temporal aspects (optional),
- comprehensibility of dynamic event sequences, e. g. race conditions,
- assessability of the static description with regard to the syntactic correctness and the semantic consistency. Meeting this criterion may be relevant for later assessments that are to be realized within the scope of quality assurance by applying the basic methods STAT - Static Analysis or SIMU - Simulation Models.
5.8.1.2 Application Criteria
The application criteria mentioned next are intended to help by selecting individual methods from the category of methods.- structure of the object of description (many distributed and simple/less concentrated, but complex functional units),
- uniqueness and comprehensibility (i. e. communicability) of the description,
- good maintainability of the methodical description with regard to the model in question.
5.8.1.3 Individual Methods
/Davis, 88/ contains an overview comparing methods for the behavior specification for event-oriented systems. The Methods Standard already includes the following basic methods: decision tables, finite automata, Pseudocode. Next, the following methods are individually introduced:- Petri Nets (PNET), (s. /Reisig, 1986/)
- State Charts (STC), (s. /Harel, 1987/)
- Specification and Description Language (SDL), (SBM part), (s. /SDL, 1985a/)
5.8.2 Individual Descriptions
5.8.2.1 Petri Nets (PNET)5.8.2.2 State Charts (STC)
5.8.2.3 Specification and Description Language (SDL)
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