TarTar: A Timed Automata Repair Tool

Abstract

We present TarTar , an automatic repair analysis tool that, given a timed diagnostic trace (TDT) obtained during the model checking of a timed automaton model, suggests possible syntactic repairs of the analyzed model. The suggested repairs include modified values for clock bounds in location invariants and transition guards, adding or removing clock resets, etc. The proposed repairs guarantee that the given TDT is no longer feasible in the repaired model, while preserving the overall functional behavior of the system. We give insights into the design and architecture of TarTar , and show that it can successfully repair 69% of the seeded errors in system models taken from a diverse suite of case studies.

An automated system repair framework with signal temporal logic

“…Repair of timed automata (TA) models has not been studied until recently [6,26,27]. In [26,27], a repair suggestion is generated by analyzing a faulty timed trace of a TA. The analysis is based on running an SMT solver on a linear arithmetic encoding of the trace.…”

“…Next, we present case studies to demonstrate our framework on TA. In our case studies, we borrow well-known UPPAAL [15] models from the literature, i.e., Fischer's protocol [23], DB from [26], SBR from [26,27], and nuclear plant and train models from [7]. To observe a faulty behavior; for Fischer's protocol and SBR, we instantiate the model with a faulty configuration; DB is already faulty; and for nuclear plant and train examples, we randomly delete guards and invariants.…”

“…Our next case study is an NTA implementing three cyclic processes, a processor and a feature deployment machine [26,27]. Due to space limitations, we invite interested reader to [27] for the details of the model. The safety specification of the model is that all processes shall finish their execution before their corresponding deadlines.…”

“…The works from [6,26,27] also aim at repairing timed automata. In [6] and [26], bounds from the existing constraints are modified.…”

“…In [6] and [26], bounds from the existing constraints are modified. The method from [26] is extended with additional repair operations including introducing resets, changing comparison operators and clock references in [27]. Our method adds new clocks and introduces new constraints over the new clocks, which allows us to detect errors of the model due to the missing clocks.…”