We propose a new approach to testing conformance to a nondeterministic specification , in which testing proceeds only as long as increased test coverage is guaranteed. In testing that a system meets a nondeterministic specification [1], it is usually assumed that the system is fair to each transition of the specification (i.e., the system will make every possible nondeterministic choice if give...

It is not easy to analyze the physical system with Petri net if the system is large-scaled and complex, mainly because the structure of the Petri net model is also complex. In order to overcome this difficulty, a decomposition method of Petri net based on an index function of places is introduced, with which a set of well-formed and structure-simple sub net systems can be obtained. For all the ...

Current garbage collectors leave much heap-allocated data uncollected because they preserve data reachable from a root set. However, only live data—a subset of reachable data—need be preserved. Using a first-order functional language we formulate a context-sensitive liveness analysis for structured data and prove it correct. We then use a 0-CFA-like conservative approximation to annotate each a...

This paper presents a method for complexity reduction in reachability analysis and safety-preserving controller synthesis via Schur-based decomposition. The decomposition results in either decoupled or weaklycoupled (lower dimensional) subsystems. Reachable sets, computed independently for each subsystem, are back-projected and intersected to yield an overapproximation of the actual reachable s...

Functional programming languages use garbage collection for heap memory management. Ideally, garbage collectors should reclaim all objects that are dead at the time of garbage collection. An object is dead at an execution instant if it is not used in future. Garbage collectors collect only those dead objects that are not reachable from any program variable. This is because they are not able to ...

Formal verification using reachability analysis has been shown to be useful for detecting design failures for controlled embedded systems, and thus to improve dependability. If the state space is hybrid, however, the growth of complexity with the dimension of the continuous dynamics limits the applicability significantly. This paper proposes an efficient approach to computing reachable sets for...

We propose a new formalism for reasoning about dynamic memory heaps, using monotonic abstraction and symbolic backward reachability analysis. We represent the heaps as graphs, and introduce an ordering on these graphs. This enables us to represent the violation of a given safety property as the reachability of a finitely representable set of bad graphs. We also describe how to symbolically comp...

test generation. The process of test generation is automated by GOTCHA, which explores the state space described by the GDL model. The user has several alternative test generation strategies, including breadth-first search, coverage-directed search, and on-the-fly test generation. Breadth-first search and on-the-fly test generation algorithms are well known. Coverage-first search involves givin...

We describe a Lohner-type algorithm for the computation of rigorous upper bounds for reachable set for control systems, solutions of ordinary differential inclusions and perturbations of ODEs.