New generations of distributed systems are opening novel perspectives for logic programming (LP): on the one hand, service-oriented architectures represent nowadays the standard approach for distributed systems engineering; on the other hand, pervasive systems mandate for situated intelligence. In this paper we introduce the notion of Logic Programming as a Service (LPaaS) as a means to address the needs of pervasive intelligent systems through logic engines exploited as a distributed service. First we define the abstract architectural model by re-interpreting classical LP notions in the new context; then we elaborate on the nature of LP interpreted as a service by describing the basic LPaaS interface. Finally, we show how LPaaS works in practice by discussing its implementation in terms of distributed tuProlog engines, accounting for basic issues such as interoperability and configurability.
MobIoT @cite_20 provides efficient service discovery, composition, and access in heterogeneous, dynamic, mobile contexts, revisiting the standard SOA approach by providing probabilistic registration, look-up and thing-based composition based on comprehensive ontologies. However, it does not support runtime interaction with users to let them specify their goals, and still needs proper validation from the scalability viewpoint when the number of registered services is very large.
@cite_20
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In this paper, we introduce MobIoT, a service-oriented middleware that enables large-scale mobile participatory sensing. Scalability is achieved by limiting the participation of redundant sensing devices. Precisely, MobIoT allows a new device to register its services only if it increases the sensing coverage of a physical attribute, along its expected path, for the set of registered devices. We present the design and implementation of MobIoT, which mobile devices use to determine their registration decision and become accessible for their services. Through experiments performed on real datasets, we show that our solution scales, while meeting sensing coverage requirements. Service Oriented Architectures and web service technology are becoming popular in recent years. As more web services can be used over the Internet, the need to find efficient algorithms for web services composition that can deal with large amounts of services becomes important. These algorithms must deal with different issues like performance, semantics or user restrictions. In this paper we present an A* algorithm which solves the problem of semantic input-output message structure matching for web service composition. Given are quest, a service dependency graph with a subset of the original services from an external repository is dynamically generated. Then, the A*search algorithm is used to find a minimal composition that satisfies the user request. Moreover, in order to improve the performance, a set of dynamic optimization techniques has been implemented over the search process. A full experimental validation with eight different public repositories has been done showing a good performance as in all tests as the algorithm finds a valid solution with minimal number of services and execution path. Service-Oriented Architecture (SOA) provides a flexible framework for service composition. Using standard-based protocols (such as SOAP and WSDL), composite services can be constructed by integrating atomic services developed independently. Algorithms are needed to select service components with various QoS levels according to some application-dependent performance requirements. We design a broker-based architecture to facilitate the selection of QoS-based services. The objective of service selection is to maximize an application-specific utility function under the end-to-end QoS constraints. The problem is modeled in two ways: the combinatorial model and the graph model. The combinatorial model defines the problem as a multidimension multichoice 0-1 knapsack problem (MMKP). The graph model defines the problem as a multiconstraint optimal path (MCOP) problem. Efficient heuristic algorithms for service processes of different composition structures are presented in this article and their performances are studied by simulations. We also compare the pros and cons between the two models. The challenge of publishing and discovering Web services has recently received lots of attention. Various solutions to this problem have been proposed which, apart from their offered advantages, suffer the following disadvantages: (i) most of them are syntactic-based, leading to poor precision and recall, (ii) they are not scalable to large numbers of services, and (iii) they are incompatible, thus yielding in cumbersome service publication and discovery. This article presents the principles, the functionality, and the design of PYRAMID-S which addresses these disadvantages by providing a scalable framework for unified publication and discovery of semantically enhanced services over heterogeneous registries. PYRAMID-S uses a hybrid peer-to-peer topology to organize Web service registries based on domains. In such a topology, each Registry retains its autonomy, meaning that it can use the publication and discovery mechanisms as well as the ontology of its choice. The viability of this approach is demonstrated through the implementation and experimental analysis of a prototype.