Timing analysis of scenario-based specifications using linear programming

Abstract

Scenario-based specifications (SBSs), such as UML interaction models, offer an intuitive and visual way of describing design requirements, and are playing an increasingly important role in the design of software systems. This paper presents an approach to timing analysis of SBSs expressed by UML interaction models. The approach considers more general and expressive timing constraints in UML sequence diagrams (SDs), and gives a solution to the reachability analysis, constraint conformance analysis and bounded delay analysis problems, which reduces these problems into linear programs. With the synchronous interpretation of the SD compositions, the timing analysis algorithms in the approach form a decision procedure for a class of SBSs where any loop in any path is time-independent of the other parts in the path. These algorithms are also a semi-decision procedure for general SBSs with both the synchronous and asynchronous composition semantics. The approach also supports bounded timing analysis of SBSs, which investigates all the paths in the bound limit one by one, and performs the timing analysis for each finite path by linear programming. A tool prototype has been developed to support this approach. SPIN which supports the design of MSCs, and allows for the creation, debugging, organization and maintenance of MSCs. Peled et al. [14,15] present a tool for searching a hierarchical MSC design for a path that matches a given specification. For SBSs with timing constraints used to describe real-time systems, the verification problems are more difficult and complicated. Some algorithms are presented by Alur et al. [6] for analysing basic MSCs with interval delays. A solution is given to the timed analogue of scenario matching by Akshay et al. [16]. Timing analysis has been extended to check UML SDs and MSC specifications [7,17,18]. However, all those works are about checking SBSs for timing consistency which is a basic property. In view of the practical use, there are a lot of properties about the accumulated delays on the traces of systems. For example, there often is a need to check if all traces of a system satisfy that the separation in time between two given events is within a given time interval, which is called bounded delay analysis. This problem has been considered for timed automata by Courcoubetis and Yannakakis [19], and for a class of Petri nets by Hulgaard and Burns [20].This paper presents an approach to timing analysis of SBSs expressed by UML interaction models. The approach gives a solution to the reachability analysis, constraint conformance analysis and bounded delay analysis problems, which reduces these problems into linear programs. With the synchronous interpretation of the SD compositions, the timing analysis algorithms in the approach form a decision procedure for a class of SBSs where any loop in any path is time-independent of the other parts in the path. These algorithms are also a semi-decision procedure for general SBSs with both the synchronous and asynchronous composition semantics. T...