Synthesis of coordination programs from linear temporal specifications

Abstract

This paper presents a method for synthesizing a reactive program which coordinates the actions of a group of other reactive programs, so that the combined system satisfies a temporal specification of its desired long-term behavior. Traditionally, reactive synthesis has been applied to the construction of a stateful hardware circuit. This work is motivated by applications to other domains, such as the IoT (the Internet of Things) and robotics, where it is necessary to coordinate the actions of multiple sensors, devices, and robots. The mathematical model represents such entities as individual processes in Hoare's CSP model. Given a network of interacting entities, called an environment, and a temporal specification of long-term behavior, the synthesis method constructs a coordinator process (if one exists) that guides the actions of the environment entities so that the combined system is deadlock-free and satisfies the given specification. The main technical challenge is that a coordinator may have only partial knowledge of the environment state, due to non-determinism within the environment, and environment actions that are hidden from the coordinator. This is the first method to handle both sources of partial knowledge, and to do so for arbitrary linear temporal logic specifications. It is shown that the coordination synthesis problem is PSPACE-hard in the size of the environment. A prototype implementation is able to synthesize compact solutions for a number of coordination problems.

Automatic Repair and Deadlock Detection for Parameterized Systems

“…Additionally, there are several approaches for synchronization synthesis and repair of concurrent systems. Some of them differ from ours in the underlying approach, e.g., being based on automata-theoretic synthesis [7,28]. Others are based on a similar underlying counterexample-guided synthesis/repair principle, but differ in other aspects from ours.…”

“…From lazy synthesis [27] we borrow the idea to construct the set of all error paths of a given length instead of a single concrete error path, but this approach only supports systems with a fixed number of components. Some of these existing approaches are more general than ours in that they support certain infinite-state processes [9,32,41], or more expressive specifications and other features like partial information [7,28].…”

“…) is the automaton that reads states of A × B k as actions and accepts all words that violate the property. 7 Example. Consider again the simple reader-writer system in Figures 5 and 4, and assume that instead of local transition (nr, {nw}, r) we have an unguarded transition (nr, Q, r).…”

“…For concurrent systems, the large number of possible interactions between processes is known to be the main challenge in guaranteeing their correctness. Therefore, we need to go beyond these existing repair approaches, and also repair the communication between processes by choosing the right options out of a set of possible interactions, a problem that is related to the idea of synchronization synthesis [7,9,38]. Moreover, we aim for an approach that avoids introducing deadlocks, which is particularly important for a repair algorithm, since often the easiest way to "repair" a system is to let it run into a deadlock as quickly as possible.…”

Adapting Behaviors via Reactive Synthesis

“…We reformulated the problem as synthesis of reactive controllers that compose with existing systems to achieve a temporal specification, e.g. [7,13,17]. Note that our work differs from such frameworks in its variables separation feature.…”