Towards Concolic Testing for Hybrid Systems

TL;DR

This paper explores combining random sampling and symbolic execution to improve the verification of hybrid systems, introducing a dynamic algorithm and a web-based tool called HyChecker.

Contribution

It proposes a novel method that adaptively switches between sampling and symbolic execution for hybrid system verification, enhancing efficiency.

Findings

HyChecker effectively verifies benchmark hybrid systems.

The dynamic switching algorithm reduces verification cost.

Hybrid approach outperforms pure sampling in effectiveness.

Abstract

Hybrid systems exhibit both continuous and discrete behavior. Analyzing hybrid systems is known to be hard. Inspired by the idea of concolic testing (of programs), we investigate whether we can combine random sampling and symbolic execution in order to effectively verify hybrid systems. We identify a sufficient condition under which such a combination is more effective than random sampling. Furthermore, we analyze different strategies of combining random sampling and symbolic execution and propose an algorithm which allows us to dynamically switch between them so as to reduce the overall cost. Our method has been implemented as a web-based checker named HyChecker. HyChecker has been evaluated with benchmark hybrid systems and a water treatment system in order to test its effectiveness.