CPSDebug: Automatic failure explanation in CPS models

AbstractDebugging cyber-physical system (CPS) models is a cumbersome and costly activity. CPS models combine continuous and discrete dynamics—a fault in a physical component manifests itself in a very different way than a fault in a state machine. Furthermore, faults can propagate both in time and space before they can be detected at the observable interface of the model. As a consequence, explaining the reason of an observed failure is challenging and often requires domain-specific knowledge. In this paper, we propose approach, a novel CPSDebug that combines testing, specification mining, and failure analysis, to automatically explain failures in Simulink/Stateflow models. In particular, we address the hybrid nature of CPS models by using different methods to infer properties from continuous and discrete state variables of the model. We evaluate CPSDebug on two case studies, involving two main scenarios and several classes of faults, demonstrating the potential value of our approach

Understanding Child Support Trends: Economic, Demographic, and Political Contributions

We use data from the Panel Study of Income Dynamics (PSID) to examine trends in child support payments over the past thirty years and to assess five different explanations for these trends: inflation, the shift to unilateral divorce, changes in marital status composition, changes in men's and women's earnings, and ineffective child support laws. We find that during the 1970s and early 1980s, three factors high inflation, increase in non-marital childbearing, and shifts to unilateral divorse--exerted downward pressure on child support payments. Throughout this time period, child support policies were weak, and average real payments declined sharply. Our findings indicate that two child support policies legislative guidelines for awards and universal wage withholding--are important for insuring child support payments. Finally, our analyses suggest that further gains in child support payments will rest with our ability to collect child support for children born to unwed parents. These children are the fastest growing group of children in the US, and they are the least likely to receive child support. To date, child support policies have been ineffective in assuring child support for never married mothers.

Welfare reform and New York City's low-income population

Welfare ; Poverty

Dynamic systems as tools for analysing human judgement

With the advent of computers in the experimental labs, dynamic systems have become a new tool for research on problem solving and decision making. A short review on this research is given and the main features of these systems (connectivity and dynamics) are illustrated. To allow systematic approaches to the influential variables in this area, two formal frameworks (linear structural equations and finite state automata) are presented. Besides the formal background, it is shown how the task demands of system identification and system control can be realized in these environments and how psychometrically acceptable dependent variables can be derived