QoS-Aware Semantic Service Selection: An Optimization Problem

Journal of Intelligent & Fuzzy Systems, 2018

The applications based on Web services (WS) composition are gaining momentum as an approach to build autonomous, heterogenous and distributed applications. Often a unique WS does not provide the required funcionality, therefore it is necessary to carry out a composition of WS in order to get the expected results. Optimizing the WS composition requires an efficient way to select the best Web services. Solving this problem can be a very complex task involving many criteria. In this work an approach is proposed to accomplish the WS selection from services previously registered and classified according to their quality of service (QoS) parameters. QoS parameters are characterized by an ontology and their values stored in a semantic database. The values of QoS corresponding to providers are collected automatically by an evaluation agent of QoS. In this way the service composition benefits from this proposal being easier and more efficient, taking into account only the best services and respecting the quality of service requirements established by the user. The results from the experiments performed with data involving real WS and artificially created data show that the proposed method is a feasible option to do a better selection of WS in the context of a WS composition.

2009

The increasing number of functionally similar services requires the existence of a non-functional properties selection process based on the Quality of Service (QoS). Thus, in this article, authors focus on the provision of a QoS model, an architecture and an implementation which enhance the selection process by the annotation of Service Level Agreement (SLA) templates with semantic QoS metrics. This QoS model is composed by a specification for annotating SLA templates files, a QoS conceptual model formed as a QoS ontology and selection algorithm. This approach, which is backward compatible, provides interoperability among customer-providers and a lightweight alternative. Finally, its applicability and benefits are shown by using examples of Infrastructure services.

Proceedings. IEEE International Conference on Web Services, 2004., 2004

The Web is moving toward a collection of interoperating Web services. Achieving this interoperability requires dynamic discovery of Web services on the basis of their capabilities. The capability of a service can be properly determined by using not only its functional description (or service interface), but also its quality attributes as judged by previous users of the service. We develop a service repository that extends UDDI registries. This repository combines an ontology of attributes with evaluation data.

2008

Most Semantic Web Services discovery approaches are based on Description Logics, allowing a limited expressiveness when describing Quality-of-Service preferences. Furthermore, DLs is not suited to perform selection tasks, because these are modeled as optimization problems. In this work, we present a hybrid discovery and selection model for Semantic Web Services that takes care of QOS preferences. Our approach splits the whole process into two stages, using the most suited engine in each one, depending on its search nature. In order to perform QOSaware discovery and selection, user preferences have to be semantically described as the rest of the service description. Our model provides an ontology for user preferences, so instances can be transformed into optimization problems that can be solved by using the most suited engine.

2010

Intensive efforts are made in the Web services selection literature by these days mainly because of the overwhelming interest of the community in the services provided over the Web. In selecting best services, the non functional properties of such services are proven to be more and more important; these describe the Quality of service that is the key factor in the selection process.In this paper, we discuss a Web service selection based on both the context and the QoS ontology. We propose an architecture that makes an automatic selection of best service provider that is based on mixed context and QoS ontology for a given set of parameters of QoS. The key idea is to rely on multi dimensional QoS. Finally, some experiments are run so to demonstrate consistency and effectiveness of the proposed method.

Informatica (Slovenia), 2016

With the growing number of web services on the Web, many approaches have been proposed to help users discover and select the desired services. Nevertheless, finding the best service that meets the user needs and preferences is still a problem. In this article, we introduce a user preferences based semantic web services discovery and selection system (PrefWS3). PrefWS3 is considered to be a user-centric system which helps users in formulating their requirements and preferences. This system involves semantic enhancement of both request and web services and provides an efficient semantic-based matching mechanism, which calculates the semantic similarity between the request and the web service. Furthermore, PrefWS3 includes a QoS-aware process and provides a reputation mechanism that enables users to evaluate the credibility of the web services they use. In this article, we also present the results of a comparison of the PrefWS3 and some other published approaches to evaluate its effect...

Computer and Information Science, 2011

Intensive efforts are made in the Web services selection literature by these days mainly because of the overwhelming interest of the community in the services provided over the Web. In selecting best services, the non functional properties of such services are proven to be more and more important; these describe the Quality of service that is the key factor in the selection process.In this paper, we discuss a Web service selection based on both the context and the QoS ontology. We propose an architecture that makes an automatic selection of best service provider that is based on mixed context and QoS ontology for a given set of parameters of QoS. The key idea is to rely on multi dimensional QoS. Finally, some experiments are run so to demonstrate consistency and effectiveness of the proposed method.

2010

With the growing number of web services on the web that offer similar functions, it is required to use mechanisms for ranking and selecting them based on non-functional properties (i.e. QoS). Different QoS models and language may use different concepts, metrics, units, values for representing QoS information. It is difficult for an automatic semantic web service discovery system to be able to understand such QoS information collected from some semantic web services in order to decide about the best semantic web service in terms of their quality. In this paper, an ontology-based approach for ranking semantic web services has been proposed. A generic and domain-specific ontology is used to infer the semantic similarity between the parameters of the request and the advertisement, which will be applied in the process of SWSs ranking. This ontology is referred to as Extended OWL-Q (EOWL-Q). Furthermore some OWL-Q disadvantages and the way of resolving them in EOWL-Q were studied to achieve a same understanding of QoS properties. Moreover, how semantic web service ranking can be used in the context of semantic web service discovery in new QoS-aware framework is explained.

2006

We present a framework for the autonomous discovery and selection of Semantic Web services based on their QoS properties. The novelty of our approach is the wide use of semantic technologies for a customizable discovery, which enables both the service users and providers to flexibly specify their matching models for QoS and the corresponding environmental conditions. In the presented approach, the discovery and ranking of services can be personalized via the use of domain ontologies detailing the user's preferences and the provider's specification. The discovery component is modeled as an adaptive query processing system in which the basic steps of filtering, matchmaking, reputation-based QoS assessment, and ranking of services correspond to logical algebraic operators, which facilitates the introduction of different discovery algorithms and the automatic generation of appropriate parallelized matchmaking evaluations, enabling the scalability of our solution up to unpredictable arrival rate of user queries against high numbers of published service descriptions in the system.

International Journal of Advanced Computer Science and Applications, 2011

Web Services are emerging technologies that enable application to application communication and reuse of services over Web. Semantic Web improves the quality of existing tasks, including Web services discovery, invocation, composition, monitoring, and recovery through describing Web services capabilities and content in a computer interpretable language. To provide most of the requested Web services, a Web service matchmaker is usually required. Web service matchmaking is the process of finding an appropriate provider for a requester through a middle agent. To provide the right service for the right user request, Quality of service (QoS)-based Web service selection is widely used. Employing QoS in Web service selection helps to satisfy user requirements through discovering the best service(s) in terms of the required QoS. Inspired by the mode of the Internet Web search engine, like Yahoo, Google, in this paper we provide a QoS-based service selection algorithm that is able to identify the best candidate semantic Web service(s) given the description of the requested service(s) and QoS criteria of user requirements. In addition, our proposed approach proposes a ranking method for those services. We also show how we employ data warehousing techniques to model the service selection problem. The proposed algorithm integrates traditional match making mechanism with data warehousing techniques. This integration of methodologies enables us to employ the historical preference of the user to provide better selection in future searches. The main result of the paper is a generic framework that is implemented to demonstrate the feasibility of the proposed algorithm for QoSbased Web application. Our presented experimental results show that the algorithm indeed performs well and increases the system reliability.