arXiv subjects

Thomas M. Grosen

Publications and source records attributed to Thomas M. Grosen.

3 recordsLinked to original sources

arXiv2026

Exploiting Assumptions for Effective Monitoring of Real-Time Properties under Partial Observability

Runtime verification of temporal properties is essential for ensuring the correctness and reliability of real-time systems, particularly in cyber-physical systems. A significant challenge in this domain is the effective prediction of property failure or success, especially when dealing with partially observable systems. This paper addresses these challenges by developing an Assumption-Based Runtime Verification (ABRV) approach for a continuous real-time setting. Our method exploits assumptions about the system's behavior, specified as Timed Automata, to enable monitors to predict future outcomes and handle unobservable system parts, such as internal faults. Properties to be monitored are specified using Metric Interval Temporal Logic (MITL). The approach also includes formalizing observations with data and time uncertainty using sequences of timed constraints. We present a zone-based online algorithm for computing the monitoring verdict, implemented on top of the UPPAAL tool. Experimental evaluation on proof-of-concept cases demonstrates the approach's feasibility and effectiveness, illustrating how assumptions facilitate earlier verdicts, enable monitoring of properties dependent on unobservable events, and provide insights into scalability.

cs.FL↗

arXiv2025

Time for Timed Monitorability

Monitoring is an important part of the verification toolbox, in particular in situations where exhaustive verification using, e.g., model-checking is infeasible. The goal of online monitoring is to determine the satisfaction or violation of a specification during runtime, i.e., based on finite execution prefixes. However, not every specification is amenable to monitoring, e.g., properties for which no finite execution can witness satisfaction or violation. Monitorability is the question of whether a given specification is amenable to monitoring, and has been extensively studied in discrete time. Here, we study the monitorability problem for real-time properties expressed as Timed Automata. For specifications given by deterministic Timed Muller Automata, we prove decidability while we show that the problem is undecidable for specifications given by nondeterministic Timed Büchi automata. Furthermore, we refine monitorability to also determine bounds on the number of events as well as the time that must pass before monitoring the property may yield an informative verdict. We prove that for deterministic Timed Muller automata, such bounds can be effectively computed. In contrast we show that for nondeterministic Timed Büchi automata such bounds are not computable.

cs.FL↗

arXiv2025

Efficient Runtime Verification of Real-Time Systems under Parametric Communication Delays

Timed Büchi automata provide a very expressive formalism for expressing requirements of real-time systems. Online monitoring and active testing 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 (or test harness, respectively) 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 or testing device. We present purely zone-based online monitoring and testing algorithms, which handle such parametric delays exactly without recurrence to costly verification procedures for parametric timed automata. We have implemented our algorithms on top of the real-time model checking tool UPPAAL, and report on encouraging initial results.

cs.FL↗