University of Minnesota
Software Engineering Center

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Yunja Choi

Recent Publications

Deviation Analysis: A New Use for Model Checking

Inaccuracies, or deviations, in the measurements of monitored variables in a control system are facts of life that control software must accommodate. Deviation analysis can be used to determine how a software specification will behave in the face of such deviations. Deviation analysis is intended to answer questions such as "What is the effect on output O if input I is off by 0 to 100?". This property is best checked with some form of symbolic execution approach. In this report we wish to propose a new approach to deviation analysis using model checking techniques.

Combination Model Checking: Approach and a Case Study.

We present combination model checking approach using a SAT-based bounded model checker together with a BDD-based symbolic model checker to provide a more efficient counter example generation process. We provide this capability without compromising the verification capability of the symbolic model checker. The basic idea is to use the symbolic model checker to determine whether or not a property holds in the model. If the property holds, we are done. If it does not, we preempt the counterexample generation and use the SAT-based model checker for this purpose.

Model Checking Requirements Specifications Using Domain Reduction Abstraction

As an automated verification and validation tool, model checking can be quite effective in practice. Nevertheless, model checking has been quite inefficient when dealing with systems with data variables over a large (or infinite) domain, which is a serious limiting factor for its applicability in practice.