Online Monitoring of Metric Temporal Logic using Sequential Networks
This paper addresses efficiency and scalability bottlenecks in online monitoring of Metric Temporal Logic (MTL) for cyber-physical systems. Methodologically, it introduces a unified monitoring framework supporting both discrete- and dense-time behaviors. Its core contribution is the first “point-free” dense-time modeling approach for MTL, circumventing theoretical limitations inherent in traditional point-based semantics and thereby enhancing monitor composability and engineering practicality. The framework integrates sequence-network-based modeling, syntactic parsing of the past-time fragment of MTL, a unified semantic construction for discrete and dense time, and synergistic optimization via term rewriting and automata-theoretic techniques. Experimental evaluation demonstrates that the prototype monitor outperforms state-of-the-art tools in both runtime speed and memory footprint, achieving real-time deployment capability.