From LTL to rLTL monitoring: improved monitorability through robust semantics

Mascle, Corto, Neider, Daniel, Schwenger, Maximilian, Tabuada, Paulo, Weinert, Alexander and Zimmermann, Martin ORCID: 0000-0002-8038-2453 (2022) From LTL to rLTL monitoring: improved monitorability through robust semantics. FORMAL METHODS IN SYSTEM DESIGN, 59 (1-3). pp. 170-204.

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Official URL: http://dx.doi.org/10.1007/s10703-022-00398-4

Abstract

Runtime monitoring is commonly used to detect the violation of desired properties in safety critical cyber-physical systems by observing its executions. Bauer et al. introduced an influential framework for monitoring Linear Temporal Logic (LTL) properties based on a three-valued semantics for a finite execution: the formula is already satisfied by the given execution, it is already violated, or it is still undetermined, i.e., it can still be satisfied and violated by appropriate extensions of the given execution. However, a wide range of formulas are not monitorable under this approach, meaning that there are executions for which satisfaction and violation will always remain undetermined no matter how it is extended. In particular, Bauer et al. report that 44% of the formulas they consider in their experiments fall into this category. Recently, a robust semantics for LTL was introduced to capture different degrees by which a property can be violated. In this paper we introduce a robust semantics for finite strings and show its potential in monitoring: every formula considered by Bauer et al. is monitorable under our approach. Furthermore, we discuss which properties that come naturally in LTL monitoring-such as the realizability of all truth values-can be transferred to the robust setting. We show that LTL formulas with robust semantics can be monitored by deterministic automata, and provide tight bounds on the size of the constructed automaton. Lastly, we report on a prototype implementation and compare it to the LTL monitor of Bauer et al. on a sample of examples.

Item Type:	Article
Uncontrolled Keywords:	Robust Linear Temporal Logic, Runtime monitoring
Divisions:	Faculty of Science and Engineering > School of Electrical Engineering, Electronics and Computer Science
Depositing User:	Symplectic Admin
Date Deposited:	02 Mar 2023 09:02
Last Modified:	02 Mar 2023 09:02
DOI:	10.1007/s10703-022-00398-4
Open Access URL:	https://doi.org/10.1007/s10703-022-00398-4
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3168677