Revisiting GPC and AND connector in real-time calculus

38th IEEE Real-Time Systems Symposium, RTSS 2017, Paris, France, 5-8 October 2017Real-Time Calculus (RTC) is a powerful framework for modeling and worst-case performance analysis of networked systems. GPC and AND are two fundamental components in RTC, which model priority-based resource arbitration and synchronization operations, respectively. In this paper, we revisit GPC and AND. For GPC, we develop tighter output arrival curves to more precisely characterize the output event streams. For AND, we first identify a problem in the existing analysis method that may lead to negative values in the output curves, and present corrections to the problem. Then we generalize AND to synchronize more than two input event streams. We implement our new theoretical results and conduct experiments to evaluate their performance. Experiment results show significant improvement of our new methods in analysis precision and efficiency.Department of Computing2017-2018 > Academic research: refereed > Refereed conference paper201811 bcm

A Model-Based Framework for the Specification and Analysis of Hierarchical Scheduling Systems

International audienceFor decades, schedulability analysis of Cyber-Physical Systems (CPS) has been conducted by analytical methods rather than model-based methods. However, CPS are getting more and more complicated, beyond the capability of analytical methods, as more sophisticated scheduling mechanisms are used. This encourages the use of model-based and automated verification techniques. These techniques must be flexible enough to be adapted to any system, and easy to use by system designers, without deep knowledge of formal verification. In this paper, we present a flexible model-based framework for specifying hierarchical scheduling systems and performing automated formal verification. It allows to easily specify complex scheduling mechanisms, with hierarchical scheduling units that can be analyzed efficiently in a compositional manner. Formal verification using statistical techniques is performed automatically by generating on-the-fly the formal models. Finally, the framework returns comprehensible feedback from the results of formal verification in the design tool