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Previous research has shown how statistical model checking can be used with human task behavior modeling and human reliability analysis to make realistic predictions about human errors and error rates. However, these efforts have not accounted for the impact that design changes can have on human reliability. In this research, we address this deficiency by using similarity theory from human cognitive modeling. This replicates how negative transfer can cause people to perform old task behaviors on modified systems. We present details about how this approach was realized with the PRISM model checker and the enhanced operator function model. We report results of a validation exercise using an application from the literature. We discuss the implications of our results and describe future research. 

Modern software systems are deployed in a highly dynamic, uncertain environment. Ideally, a system that is robust should be capable of establishing its most critical requirements even in the presence of possible deviations in the environment. We propose a technique called behavioral robustification, which involves systematically and rigorously improving the robustness of a design against potential deviations. Given behavioral models of a system and its environment, along with a set of user-specified deviations, our robustification method produces a redesign that is capable of satisfying a desired property even when the environment exhibits those deviations. In particular, we describe how the robustification problem can be formulated as a multi-objective optimization problem, where the goal is to restrict the deviating environment from causing a violation of a desired property, while maximizing the amount of existing functionality and minimizing the cost of changes to the original design. We demonstrate the effectiveness of our approach on case studies involving the robustness of an electronic voting machine and safety-critical interfaces.