In this paper, we apply a compositional proof technique to an automatic verification of the correctness of Fischer's mutual exclusion protocol. It is demonstrated that the technique may avoid the state-explosion problem. Our compositional technique has recently been implemented in a tool CMC, which gives experimental evidence that the size of the verification effort required of the technique only grows polynomially in the size of the number of processes in the protocol. In particular, CMC verifies the protocol for 50 processes within 172.3 seconds and using only 32MB main memory. In contrast

An input/output--link control protocol is modeled and analyzed in the real-time model checker Uppaal. The protocol is supposed to sit in an audio/video component and control (read from and write to) a link to neighbour audio/video components. The component may for example be a TV, and a neighbour may be a VCR. The protocol also communicates with the remote--control. The protocol is in addition responsible for the powering up and down of the component in between the arrival of data. It is this power control that is the focus of the modeling and verification demonstrated in this report. The work has been carried out in a collaboration between Aalborg University and the audio/video company B&O, which plans to incorporate the protocol as part of a new product line. The work was carried out in a limited period of 3 weeks, with an attempt to examine how well such a collaboration would proceed. The paper elaborates on the lessons learned. Amongst

Since real-time systems often operate in safety-critical environments it is extremely important that they function correctly. Uppaal is a tool that can be used for validation and verification of real-time systems. The user models the system using networks of timed automata and uses a simple logic to express safety requirements that the modelled system must satisfy to guarantee its correct behaviour. Uppaal then performs reachability analysis using constraint solving techniques to check if the model satisfies the given requirements. In addition, the tool is also able to provide the user with a sample execution that explains why a requirement is (or is not) satisfied by the model. The analysis is fully automated. This thesis describes various techniques adopted when implementing Uppaal. Some of he techniques have improved the performance of Uppaal significantly. We have studied the techniques with performance measurements in several case-studies. One of the main contributions is the comparison of different strategies in implementing the basic data structures and searching algorithms. The measurements can be used as hints on what parts of the model-checker that are most important to optimise. Though the techniques are studied in the context of timed automata, we believe that they are applicable to the implementation of

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