1 research outputs found
Online Quantitative Timed Pattern Matching with Semiring-Valued Weighted Automata
Monitoring of a signal plays an essential role in the runtime verification of
cyber-physical systems. Qualitative timed pattern matching is one of the
mathematical formulations of monitoring, which gives a Boolean verdict for each
sub-signal according to the satisfaction of the given specification. There are
two orthogonal directions of extension of the qualitative timed pattern
matching. One direction on the result is quantitative: what engineers want is
often not a qualitative verdict but the quantitative measurement of the
satisfaction of the specification. The other direction on the algorithm is
online checking: the monitor returns some verdicts before obtaining the entire
signal, which enables to monitor a running system. It is desired from
application viewpoints. In this paper, we conduct these two extensions, taking
an automata-based approach. This is the first quantitative and online timed
pattern matching algorithm to the best of our knowledge. More specifically, we
employ what we call timed symbolic weighted automata to specify quantitative
specifications to be monitored, and we obtain an online algorithm using the
shortest distance of a weighted variant of the zone graph and dynamic
programming. Moreover, our problem setting is semiring-based and therefore,
general. Our experimental results confirm the scalability of our algorithm for
specifications with a time-bound.Comment: Accepted to FORMATS 201