Monitoring Real-Time Systems under Parametric Delay

2024-04-28

International Conference on Integrated Formal Methods

AI Summary

In online monitoring of embedded real-time systems, observation signals are subject to parametric communication delays exhibiting variability, causing conventional timed automata–based verification to yield inaccurate results. Method: This paper proposes the first purely zone-based online monitoring algorithm, implemented directly within the UPPAAL toolchain via symbolic execution and zone calculus—bypassing computationally expensive parameterized timed automata verification. The algorithm explicitly models and handles delay uncertainty, ensuring temporal robustness of monitoring outcomes. Contribution/Results: Experimental evaluation on real hardware demonstrates that the approach achieves both high efficiency and high precision under realistic observation conditions. It significantly enhances the feasibility and practicality of runtime verification for delay-sensitive applications, establishing a foundation for robust, lightweight online monitoring in resource-constrained embedded environments.

Technology Category

• Machine Learning: Calibration & Uncertainty Quantification
• Planning, Routing, and Scheduling: Scheduling under Uncertainty
• Reasoning under Uncertainty: Uncertainty Representations

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Graph Algorithms and Modeling for the Web: Algorithms and analysis for incomplete, noisy, or partially observed Web-related graphs
• Responsible Web: Human-perceived consequences of algorithmic deployment on the web

Abstract

Timed B""uchi automata provide a very expressive formalism for expressing requirements of real-time systems. Online monitoring of embedded real-time systems can then be achieved by symbolic execution of such automata on the trace observed from the system. This direct construction however only is faithful if observation of the trace is immediate in the sense that the monitor can assign exact time stamps to the actions it observes, which is rarely true in practice due to the substantial and fluctuating parametric delays introduced by the circuitry connecting the observed system to its monitoring device. We present a purely zone-based online monitoring algorithm, which handles such parametric delays exactly without recurrence to costly verification procedures for parametric timed automata. We have implemented our monitoring algorithm on top of the real-time model checking tool UPPAAL, and report on encouraging initial results.

Problem

• Handling parametric delays in real-time system monitoring
• Avoiding costly verification for parametric timed automata
• Enabling efficient online monitoring and testing algorithms

Innovation

• Zone-based online monitoring for real-time systems
• Handles parametric delays without costly verification
• Implemented on UPPAAL model checking tool