P is a domain-specific language designed for specifying asynchronous, event-driven systems. Its computational model is based on actors, i.e., on communicating state machines. This paper presents a formal semantics of P using rewriting logic, extending the language's verification capabilities. Implemented in Maude, a rewriting logic language, this semantics enables automated analysis of P programs, including reachability analysis, LTL model checking, and statistical model checking. Through illustrative examples, this paper demonstrates how this formalization significantly enhances P 's verification capacities in practical scenarios.

Abstract The problem of service composition is the process of assigning resources to services from a pool of available ones in the shortest possible time so that the overall quality of service is maximized. This article provides solutions for the composition problem that takes into account its scalability, services' locations, and users' restrictions, which are key for the management of applications using state‐of‐the‐art technologies. The provided solutions use different techniques, including genetic algorithms and heuristics. We provide an extensive experimental evaluation, which shows the pros and cons of each of them, and allows us to characterize the preferred option for each specific problem. Since no solution dominates the others, we propose a decision tree, based on our results, to select the best composition algorithm in each situation.

Abstract This paper addresses the problem of approximating the set of all solutions for Multi-objective Markov Decision Processes. We show that in the vast majority of interesting cases, the number of solutions is exponential or even infinite. In order to overcome this difficulty we propose to approximate the set of all solutions by means of a limited precision approach based on White’s multi-objective value-iteration dynamic programming algorithm. We prove that the number of calculated solutions is tractable and show experimentally that the solutions obtained are a good approximation of the true Pareto front.