Service Composition Engine Research Articles

Interoperability in semantic Web of Things: Design issues and solutions

SummaryThe significant improvement in processing power, communication, energy consumption, and the size of computational devices has led to the emergence of the Internet of Things (IoT). IoT projects raise many challenges, such as the interoperability between IoT applications because of the high number of sensors, actuators, services, protocols, and data associated with these systems. Semantics solves this problem by using annotations that define the role of each IoT element and reduces the ambiguity of information exchanged between the devices. This work presents SWoTPAD, a semantic framework that helps in the development of IoT projects. The framework is designer oriented and provides a semantic language that is more user‐friendly than OWL‐S and WSML and allows the IoT designer to specify devices, services, environment, and requests. Following this, it makes use of these specifications and maps them for RESTful services. Additionally, it generates an automatic service composition engine that is able to combine services needed to handle complex user requests. We validated this approach with two case studies. The former concerns a residential security system and the latter, the cloud application deployment. The average time required for service discovery and automatic service composition corresponds to 72.9% of the service execution time in the case study 1 and 64.4% in the case study 2.

Toward Supporting Unplanned Dynamic Changes of Service-Based Business Processes

Service-oriented architecture (SOA) has become an application development paradigm widely recognized both in academia and in industry. Although SOA-based applications may vertically implement business processes through the composition of loosely coupled services, they have to face frequent changes, such as unavailability of service (due to the uncontrollable, dynamic, and distributed environments) or dynamic replacement of service (due to specific user requirements). This indicates that the service compositions are expected to be adaptable enough to cater to such changing situations. In this paper, we propose an approach to supporting unplanned dynamic changes of service compositions by combining variability management and dynamic binding. The proposed approach introduces the concept of abstract proxy services in a variability-supporting service composition language, namely VxBPEL, and provides a mechanism to support variation design and dynamic binding for unplanned changes at run time. To realize the proposed approach, we have developed a service composition engine that supports abstract proxy services and their run-time replacement via service discovery or user intervention. Finally, a case study has been conducted to demonstrate the feasibility of the proposed approach and quantify the performance overhead resulting from runtime variability management and dynamic binding. The experimental results show that the proposed approach overcomes the limitation of imperative variability-based approaches in handling unplanned dynamic changes and further enhances the dynamic adaptability of VxBPEL-based service compositions.

Data integration using service composition in data service middleware

ABSTRACTService‐oriented computing has emerged as the state‐of‐the‐art distributed computing model for loosely coupled service‐centric business applications. Specifically, service‐oriented computing techniques allow organizations to compose Web services. Indeed, the organizational capacity to compose Web services has received much interest, particularly with respect to supporting business‐to‐business or enterprise application integration. In this paper, we present a system that proposes to adopt service composition as a new approach to integrate data from various data sources. We specify the business process description language as well as the service composition engine that supports the proposed language. We also present different strategies for executing a composite data service call. Copyright © 2013 John Wiley & Sons, Ltd.

Context-sensitive user interfaces for semantic services

Service-centric solutions usually require rich context to fully deliver and better reflect on the underlying applications. We present a novel use of context in the form of customized user interface services with the concept of User Interface as a Service (UIaaS). UIaaS takes user profiles as input to generate context-aware interface services. Such interface services can be used as context to augment semantic services with contextual information leading to UIaaS as a Context (UIaaSaaC). The added serendipitous benefit of the proposed concept is that the composition of a customized user interface with the requested service is performed by the service composition engine, as is the case with any other services. We use a special-purpose language (called User Interface Description Language (UIDL)) to model and realize user interfaces as services. We use a real-life e-government application, human services delivery for the citizens, as a proof-of-concept. We also present a comprehensive evaluation of the proposed approach using a functional evaluation and a nonfunctional evaluation consisting of an end user usability test and expert usability reviews.

Semantics Web service composition engine based on topic maps

With regard to the problems like flow control and throughput of Web service composition,a topic-map-based semantics Web service composition engine was proposed,in which some Web services would be described via ontology and topic map.Web services and topic maps were abstracted by using these description languages which included OWL-S and XTM.Web service topic was employed to express semantics Web service,which aimed to use characteristic of topic maps.And topic maps expediently implemented positioning and navigation of information resource,such as Web services,which made states and goal of Web services definite.Thus,to define UDDI registration(UDDIr) and retrieval capability(UDDIs),grammar checking(GD) and semantics recognition capability(SI),similarity(STS),matching(STM),sufficiency(STF) of Web service topics,facet classification capability of Web service topics characteristics(SFC),access right of Web service topics(STP),facet depth decision(FDD) and interoperability capability(STC) to set up service composition engine approach,and employ mathematical method to describe and define.Finally,Java was employed to develop Web service composition engine.The experimental results show that it is feasible and effective.

A Flexible Directory Query Language for the Efficient Processing of Service Composition Queries

Service composition is a major challenge in an open environment populated by large numbers of heterogeneous services. In such a setting, the efficient interaction of directory-based service discovery with service composition engines is crucial. In this article we present a Java-based directory that offers special functionality enabling effective service composition. In order to optimize the interaction of the directory with different service composition algorithms exploiting application-specific heuristics, the directory supports user-defined selection and ranking functions written in a declarative query language. Inside the directory queries are transformed and compiled to JVM bytecode which is dynamically linked into the directory. The compiled query enables a best-first search of matching directory entries, efficiently pruning the search space.

A Multiagent System for the Reliable Execution of Automatically Composed Ad-hoc Processes

This article presents an architecture to automatically create ad-hoc processes for complex value-added services and to execute them in a reliable way. The uniqueness of ad-hoc processes is to support users not only in standardized situations like traditional workflows do, but also in unique non-recurring situations. Based on user requirements, a service composition engine generates such ad-hoc processes, which integrate individual services in order to provide the desired functionality. Our infrastructure executes ad-hoc processes by transactional agents in a peer-to-peer style. The process execution is thereby performed under transactional guarantees. Moreover, the service composition engine is used to re-plan in the case of execution failures.

On-the-fly Construction of Web Services Compositions from Natural Language Requests

The introduction of Semantic Web techniques in Service-oriented Architectures enables explicit representation and reasoning about semantically rich descriptions of service operations. Those techniques hold promise for the automated discovery, selection, composition and binding of services. This paper describes an approach to derive formal specifications of Web Service compositions on the basis of the interpretation of informal user requests expressed in restricted Natural Language. Our approach leverages the semantic and ontological description of a portfolio of known service operations (called the Semantic Service Catalog). Each user request is processed against a Natural Language vocabulary that includes lexical constructs designed to convey the operations' semantics, in order to recognize and extract fundamental functional requirements implied by the request, and associate them to entries in the Catalog. In addition, the request interpreter extracts from the request the overall service logic, expressed in terms of a set of modular templates describing control and data flow among the selected operations. The result is a composition specification that associates on demand each user request to a new composed service. That specification is formal and can thus be transformed in an executable flow document for a target service composition engine.