Evolutionary algorithms, such as particle swarm optimization (PSO), are widely applied to UAV path planning problems. However, the fixed particle length of PSO, which may not be suitable for the scenario, will compromise the search efficiency. This paper proposes the RGG-PSO+ method, which adapts to scenarios by dynamically adjusting the number of waypoints. Random geometric graphs (RGG) and the divide-and-conquer paradigm are involved in improving the proposed method. Comparative analyses with established heuristic methods demonstrate RGG-PSO+’s superior performance in complex environments, particularly in terms of convergence speed and path length. The implementation of RGG significantly improves the F-Measure, indicating a shift from exploration to exploitation of PSO’s iterations, and the implementation of the divide-and-conquer paradigm is evident in the improved mean and variance of normalized path lengths.

We introduce a goal-aware extension of responsibility-sensitive safety (RSS), a recent methodology for rule-based safety guarantee for automated driving systems (ADS). Making RSS rules guarantee goal achievement—in addition to collision avoidance as in the original RSS—requires complex planning over long sequences of manoeuvres.To deal with the complexity, we introduce a compositional reasoning framework based on program logic, in which one can systematically develop RSS rules for smaller subscenarios and combine them to obtain RSS rules for bigger scenarios. As the basis of the framework, we introduce a program logic $\text{dFHL}$ that accommodates continuous dynamics and safety conditions. Our framework presents a $\text{dFHL}$-based workflow for deriving goal-aware RSS rules; we discuss its software support, too. We conducted experimental evaluation using RSS rules in a safety architecture. Its results show that goal-aware RSS is indeed effective in realising both collision avoidance and goal achievement.

Deep Neural Networks (DNNs) are finding a place at the heart of more and more critical systems, and it is necessary to ensure they perform in as correct a way as possible. Search-based repair methods, that search for new values for target neuron weights in the network to better process fault-inducing inputs, have shown promising results. These methods rely on fault localisation to determine what weights the search should target. However, as the search progresses and the network evolves, the weights responsible for the faults in the system will change, and the search will lose in effectiveness. In this work, we propose an adaptive search method for DNN repair that adaptively updates the target weights during the search by performing fault localisation on the current state of the model. We propose and implement two methods to decide when to update the target weights, based on the progress of the search's fitness value or on the evolution of fault localisation results. We apply our technique to two image classification DNN architectures against a dataset of autonomous driving images, and compare it with a state-of-the art search-based DNN repair approach.

The Multi-Agent Path Finding (MAPF) problem, i.e., the scheduling of multiple agents to reach their destinations, has been widely investigated. Testing MAPF systems is challenging, due to the complexity and variety of scenarios and the agents’ distribution and interaction. Moreover, MAPF testing suffers from the oracle problem, i.e., it is not always clear whether a test shows a failure or not. Indeed, only considering whether the agents reach their destinations without collision is not sufficient. Other properties related to the ‘quality’ of the generated paths should be assessed, e.g., an agent should not follow an unnecessarily long path. To tackle this issue, this article proposes MET-MAPF, a Metamorphic Testing approach for MAPF systems. We identified 10 Metamorphic Relations (MRs) that a MAPF system should guarantee, designed over the environment in which agents operate, the behaviour of the single agents and the interactions among agents. Starting from the different MRs, MET-MAPF automatically generates test cases addressing them, so possibly exposing different types of failures. Experimental results show that MET-MAPF can indeed find MR violations not exposed by approaches that only consider the completion of the mission as test oracle. Moreover, experiments show that different MRs expose different types of violations.

Service disruptions due to deliberate sabotage are serious threats to supply systems. To alleviate the loss of accessibility caused by such disruptions, identifying the system vulnerabilities that would be worth strengthening is a critical problem in critical infrastructure protection. Today's supply systems tend to be organized in a decentralized manner, with different components belonging to different entities, keeping much information private. Therefore, a protection plan must balance its benefits among these entities for universal agreement to be reached. This paper addresses the issue of decentralized supply chain fortification by proposing the R-Interdiction Median problem with Fortification for Decentralized supply systems (D-RIMF). In the D-RIMF, each demand node is private and is a client of a certain facility; each facility evaluates its potential worst-case reduction in accessibility, measured as the increase in service provision costs considering only its own clients, and the objective is to minimize the largest evaluation values. To model the D-RIMF, we introduce a bilevel multiagent framework, in which all facilities and the defender are considered as independent agents. To solve the D-RIMF, both heuristic and optimal algorithms are designed to satisfy different requirements. Finally, the usefulness of the D-RIMF and the performances of the proposed algorithms are observed through simulations performed on typical datasets.