Bu Lei

An Instrumentation Tool for Program Dynamic Analysis in Java

Dynamic analysis has been widely used in program analysis. Instrumentation is a general technology used to trace dynamic behavior of software. This paper presents a java source code instrumentation tool, which supports making instrumentation manually and automatically according to rules based on AST analysis. On one hand, users can instrument source code manually. It supports to manage those instrumentation points. On the other hand, code snippets can be instrumented automatically in compliance with criteria defined by users. This tool defines some inside criteria and makes instrumentation automatically for them. Whats more, these inside criteria can be expanded. By instrumentation, a dynamic execution report about the java source code can be obtained.

Composed IIS path locating based optimization for bounded \\reachability analysis of compositional linear hybrid systems}{Composed IIS path locating based optimization for bounded reachability analysis of compositional linear hybrid systems

Hybrid systems include both discrete and continuous behavior and are widely used to model control systems. The reachability analysis of its unsafe state is an important method for guaranteeing the safety of a system. However, the current techniques do not scale well to the problems of practical interest. Due to the synchronization of components and the combinatorial explosion of state space, the reachability analysis of compositional linear hybrid system is extremely complex. In order to reduce the complexity, a path-oriented approach was proposed in a previous work, which conducted bounded reachability analysis of a compositional linear hybrid system. By enumerating and verifying each potential path one by one, the size of the problem that can be solved will be increased substantially. This path-oriented approach will become quite inefficient due to a sharp increase in the number of candidate paths when analyzing complex systems. The path explosion problem in model checking is also famous. To solve this problem, we propose a state-space reduction technique, which accelerates the verification process. We propose a method to locate the cause of infeasibility, when a composed infeasible path segment after a path set is proved to be infeasible. As we can simply falsify a path set that contains a composed infeasible path segment, the number of candidate paths can be reduced significantly. Furthermore, to avoid such composed path segments efficiently, we propose an approach based on satisfiability modulo theories (SMT), to traverse the bounded graph structure of the composed linear hybrid system. The results of the experiment show that the performance of the path-oriented bounded reachability analysis can be optimized significantly and that the overall performance of the proposed approach is better than that of the state-of-the-art competitor.

Modeling and analysis of wireless sensor network protocols by stochastic timed automata and statistical model checking

Recently, sensor technology has seen significant achievement. Meanwhile, Wireless Sensor Network (WSN) technique has attracted lots of attention because of its open and dynamic behaviors, and has become a very important component of the Internet-based computing. The behavior of WSN system is very complex and may encounter lots of stochastic uncertainties and disturbances like message loss and node dynamics. Furthermore, WSN system is difficult to change and maintain once it is deployed. Thus, it is critical to ensure the quality of the low level protocols of WSN system in design phase. Designers should ensure the logical correctness of a protocol, as well as evaluate the performance of the protocol under certain target environments. To handle these issues, in this paper, we propose a framework to analyze and evaluate WSN protocols based on stochastic timed automata and statistical model checking. We propose to address the modeling of the uncertainties in the realistic behaviors by weighted stochastic transitions in the timed automata model of the protocol. Furthermore, we propose that the performance of the protocol under realistic environments should be evaluated by statistical model checking which is much cheaper and more scalable. To illustrate the feasibility and detail of the modeling and verification approach presented in this paper, two well-known WSN protocols, Timing-sync Protocol for Sensor Networks (TPSN) and Flooding Time Synchronization Protocol (FTSP), are studied thoroughly throughout the paper.

Scenario-Based timing consistency checking for time petri nets

In this paper, we solve the consistency checking problems of concurrent and real-time system designs modelled by time Petri nets for the scenario-based specifications expressed by message sequence charts (MSCs). The algorithm we present can be used to check if a time Petri net satisfies a specification expressed by a given MSC which requires that if a scenario described by the MSC occurs during the run of the time Petri net, the timing constraints enforced to the MSC must be satisfied.In this paper, we solve the consistency checking problems of concurrent and real-time system designs modelled by time Petri nets for the scenario-based specifications expressed by message sequence charts (MSCs). The algorithm we present can be used to check if a time Petri net satisfies a specification expressed by a given MSC which requires that if a scenario described by the MSC occurs during the run of the time Petri net, the timing constraints enforced to the MSC must be satisfied.