Science of Computer Programming最新文献

Programming swarm behaviors is a challenging task, due to the need to express collective behaviors in terms of local interactions among simple agents. Even if several programming frameworks have been proposed, they are often based on low-level abstractions, which makes the development of swarm applications complex and error-prone. Thus, we present MacroSwarm, an aggregate programming framework for the development of swarm behaviors. With this framework, it is possible to define a large variety of swarm behaviors, starting from simple movements to more complex ones, such as aggregation, flocking, and collective decision-making. In this paper, we present the main features of the framework and some simple examples of its API usage.

The development of microservice systems is complex due to the impact consistency problems have on the business logic design. On the other hand, the implementation of a microservice requires extensive use of middleware technology, which delays the test and identification of the cases where consistency problems can occur. We introduce the Microservices Simulator object-oriented framework that supports the rapid prototyping of a microservice system designed according to the Transactional Causal Consistency model.

Hybrid dynamical systems describe the mixed discrete dynamics and continuous dynamics of cyber-physical systems such as aircraft, cars, trains, and robots. To justify correctness properties of the safety-critical control algorithms for their physical models, differential dynamic logic (

Software Testing is normally one of the main forms of verification and validation used in software development but it is often manual and so expensive and error prone. One of the proposed solutions to this is to use model-based testing, in which testing is based on a model of how the system should behave. If the model has a formal semantics, then there is potential to automate systematic test generation. In this paper we consider the case where the semantics of the model is a set of refusal traces, also called failure traces. We show how the notions of fundamental refusal and fundamental refusal trace can be used to derive a normalised transition system, which we call an observation transition system (OTS), from the semantics. We then show how, if this OTS has finitely many states, and we are given a bound m, one can produce a corresponding complete test suite: one that is guaranteed to determine correctness as long as the number of states of the OTS defined by the semantics of the system under test has no more than m states. In practice, the choice of value for m might be based on domain knowledge or a cost-benefit analysis. As far as we are aware, this is the first work to show how a finite complete test suite can be derived when the semantics under consideration is a set of refusal traces.

TADA is a unique toolkit designed to foster the use and implementation of approximate distributed agreement primitives. Developed in Java, TADA provides ready-to-use implementations of several approximate agreement algorithms, as well as the tools to enable programmers/researchers to easily implement further protocols: A template that enables new protocol implementations to be created by simply changing specific functions; and high-level abstractions for communication and concurrency control. As an example, the toolkit includes a ready-to-use implementation for clock synchronisation between distributed processes. Further use cases can include sensor input stabilisation and distributed machine learning, or other instances of distributed agreement where network synchrony cannot be assumed, byzantine fault tolerance may be required and a bounded divergence in decision values can be tolerated.

This article introduces ScaRLib, a Scala-based framework that aims to streamline the development cyber-physical swarms scenarios (i.e., systems of many interacting distributed devices that collectively accomplish system-wide tasks) by integrating macroprogramming and multi-agent reinforcement learning to design collective behavior. This framework serves as the starting point for a broader toolchain that will integrate these two approaches at multiple points to harness the capabilities of both, enabling the expression of complex and adaptive collective behavior.

The TLA⁺ Proof System (TLAPS) allows users to verify proofs with the support of automated theorem provers, including SMT solvers. To increase trust in TLAPS, we revisited the encoding of TLA⁺ for SMT, whose implementation had become too complex. Our approach is based on a first-order axiomatization with E-matching patterns. The new encoding is available with TLAPS and achieves performances similar to the previous version, despite its simpler design.

This paper introduces the IPFS requested content location service, a software service to monitor the operation of IPFS from the perspective of the content requested through IPFS gateways. The software is provided as a docker stack that consumes the logs of one or more IPFS gateways, extracts the CID of the requested content and the IP address of the requester, and queries the IPFS network for the providers of the content. The software also matches the IP addresses of the requesters and providers with their geographic location, and stores the results in a database for later analysis. The software has been used in our previous measurement study, published at DAIS'23, that analyzed the operation of IPFS from the perspective of the content requested through gateways.

Context. Several Research areas emerged and have been proceeding independently when in fact they have much in common. These include: mutant subsumption and mutant set minimization; relative correctness and the semantic definition of faults; differentiator sets and their application to test diversity; generate-and–validate methods of program repair; test suite coverage metrics.

Objective. Highlight their analogies, commonalities and overlaps; explore their potential for synergy and shared research goals; unify several disparate concepts around a minimal set of artifacts.

Method. Introduce and analyze a minimal set of concepts that enable us to model these disparate research efforts, and explore how these models may enable us to share insights between different research directions, and advance their respective goals.

Results. Capturing absolute (total and partial) correctness and relative (total and partial) correctness with a single concept: detector sets. Using the same concept to quantify the effectiveness of test suites, and prove that the proposed measure satisfies appealing monotonicity properties. Using the measure of test suite effectiveness to model mutant set minimization as an optimization problem, characterized by an objective function and a constraint.

Generalizing the concept of mutant subsumption using the concept of differentiator sets. Identifying analogies between detector sets and differentiator sets, and inferring relationships between subsumption and relative correctness.

Conclusion. This paper does not aim to answer any pressing research question as much as it aims to raise research questions that use the insights gained from one research venue to gain a fresh perspective on a related research issue.