Striver: Stream Runtime Verification for Real-Time Event-Streams

Abstract

We study the problem of monitoring rich properties of real-time event streams, and propose a solution based on Stream Runtime Verification (SRV), where observations are described as output streams of data computed from input streams of data. SRV allows a clean separation between the temporal dependencies among incoming events, and the concrete operations that are performed during the monitoring. SRV specification languages typically assume that all streams share a global synchronous clock and input events arrive in a synchronous manner. In this paper we generalize the time assumption to cover real-time event streams, but keep the essential explicit time dependencies present in synchronous SRV languages. We introduce Striver, which shares with SRV the simplicity, and the separation between the timing reasoning and the data domain. Striver is a general language that allows to express other real-time monitoring languages. We show in this paper translations from other formalisms for (piece-wise constant) signals and timed event streams. Finally, we report an empirical evaluation of an implementation of Striver.