Reasoning about multithreaded object-oriented programs is difficult, due to the non-local nature of object aliasing, data races, and deadlocks. We propose a programming model that prevents data races and deadlocks, and supports local reasoning in the presence of object aliasing and concurrency. Our programming model builds on the multi-threading and synchronization primitives as they are presen...

This paper concerns the coordination and traffic management of a group Automated Guided Vehicles (AGVs) moving in real industrial scenario, such as an automated factory or warehouse. The proposed methodology is based on three-layer control architecture, which described follows: 1) Top Layer (or Topological Layer) allows to model vehicles among different areas environment; 2) Middle path planner...

This paper describes a method for coordinating the independently planned trajectories of multiple mobile robots to avoid collisions and deadlocks among them. Whenever the distance between two robots drops below a certain value, they exchange information about their planned trajectories and determine whether they are in danger of a collision. If a possible collision is detected, they monitor the...

Establishing the absence of deadlocks is important in many applications of formal methods. The use of model checking for finding deadlocks in formal models is limited because in many industrial applications the state space is either infinite or much too large to be explored exhaustively. In this paper we propose a constraint-based approach to finding deadlocks employing the ProB constraint solv...

Deadlocks are a common error in programs with lock-based concurrency and are hard to avoid or even to detect. One way for deadlock prevention is to deadlocks. Often static approaches try to confirm that the lock-taking statically analyze the program code to spot sources of potential adheres to a given order, or, better, to infer that such an order exists. Such an order precludes situations of c...

Modern production facilities (i.e., flexible manufacturing systems) exhibit a high degree of resource sharing, a situation in which deadlocks (circular waits) can arise. Using digraph theoretic concepts we derive necessary and sufficient conditions for a deadlock occurrence and rigorously characterize highly undesirable situations (second level deadlocks), which inevitably evolve to circular wa...

This paper presents a graph-based dynamic verification algorithm for deadlock detection and avoidance specialised in barrier synchronisation. Barriers are used to coordinate the execution of groups of tasks, and serve as a building block of parallel computing. The synchronisation patterns enabled by current barrier-based abstractions can introduce deadlocks, a major issue in getting parallel ap...

Concurrency bugs are widespread in multithreaded programs. Fixing them is time-consuming and error-prone. We present CFix, a system that automates the repair of concurrency bugs. CFix works with a wide variety of concurrency-bug detectors. For each failure-inducing interleaving reported by a bug detector, CFix first determines a combination of mutual-exclusion and order relationships that, once...

In this paper we illustrate a compositional method for modeling the concurrent execution of working processes in flexible manufacturing systems (FMS) through a special class of Petri Nets that we call S 'PI?. In essence, this class is built from state machines sharing a set of places modeling the availability of system resources. The analysis of S ' P R leads us to characterize deadlock situati...

Formal dynamic analysis of MPI programs is crucially important in the context of developing HPC applications. Existing dynamic verification tools for MPI programs suffer from exponential schedule explosion, especially when multiple non-deterministic receive statements are issued by a process. In this paper, we focus on detecting message-orphaning deadlocks within MPI programs. For this analysis...