Synthesis of behavioral models from scenarios

Abstract

Scenario-based specifications such as Message Sequence Charts (MSCs) are useful as part of a requirements specification. A scenario is a partial story, describing how system components, the environment, and users work concurrently and interact in order to provide system level functionality. Scenarios need to be combined to provide a more complete description of system behavior. Consequently, scenario synthesis is central to the effective use of scenario descriptions. How should a set of scenarios be interpreted? How do they relate to one another? What is the underlying semantics? What assumptions are made when synthesizing behavior models from multiple scenarios? In this paper, we present an approach to scenario synthesis based on a clear sound semantics, which can support and integrate many of the existing approaches to scenario synthesis. The contributions of the paper are threefold. We first define an MSC language with sound abstract semantics in terms of labeled transition systems and parallel composition. The language integrates existing approaches based on scenario composition by using high-level MSCs (hMSCs) and those based on state identification by introducing explicit component state labeling. This combination allows stakeholders to break up scenario specifications into manageable parts and reuse scenarios using hMCSs; it also allows them to introduce additional domainspecific information and general assumptions explicitly into the scenario specification using state labels. Second, we provide a sound synthesis algorithm which translates scenarios into a behavioral specification in the form of Finite Sequential Processes. This specification can be analyzed with the Labeled Transition System Analyzer using model checking and animation. Finally, we demonstrate how many of the assumptions embedded in existing synthesis approaches can be made explicit and modeled in our approach. Thus, we provide the basis for a common approach to scenario-based specification, synthesis, and analysis.

Composition of Use Cases Using Synchronization and Model Checking

“…Many approaches have been developed to synthesize state-based models from a set of use cases [5][6][7][8][9][10][11]. State-based models are basically needed to verify and validate the user requirements in order to detect design problems as soon as possible.…”

“…There are two kinds of state characterization: trace-based [5][6][7]16], and variable (or label) state-based characterization [8,9,17 ]. In this paper, we propose to detect these states using a model checking approach.…”

“…Rule (7) defines the set of the states of the builder FSA while Rule (8) defines the set of its final states. Rule (9) shows that the labeling of all the transitions that are not outgoing from s are labeled with the same label a. Rule (10) demonstrates that from the state s new added transitions labeled with f s (begin) and f s (end) synchronize with the builder of referred use case clone.…”

Synthesis and Refinement Check of Sequence Diagrams

“…Modeling sequence diagrams with process algebra has also been studied [7]- [9], [20], [21]. Korenblat et al [7] proposed the method for modeling UML state machine diagrams and sequence diagrams by π-calculus.…”

“…Uchitel et al [9], [20] presented the procedure to integrate multiple sequence diagrams into an FSP and carry out formal verification using LTSA. This framework for the integration is based on the use of hMSCs.…”