Robustness of Specifications and Its Applications to Falsification, Parameter Mining, and Runtime Monitoring with S-TaLiRo

Logical specifications have enabled formal methods by carefully describing what is correct, desired or expected of a given system. They have been widely used in runtime monitoring and applied to domains ranging from medical devices to information security. In this tutorial, we will present the theory and application of robustness of logical specifications. Rather than evaluate logical formulas to Boolean valuations, robustness interpretations attempt to provide numerical valuations that provide degrees of satisfaction, in addition to true/false valuations to models. Such a valuation can help us distinguish between behaviors that “barely” satisfy a specification to those that satisfy it in a robust manner. We will present and compare various notions of robustness in this tutorial, centered primarily around applications to safety-critical Cyber-Physical Systems (CPS). We will also present key ways in which the robustness notions can be applied to problems such as runtime monitoring, falsification search for finding counterexamples, and mining design parameters for synthesis.