VOLARE: Adaptive Web Service Discovery Middleware for Mobile Systems

With the recent advent and widespread use of smart mobile devices, the flexibility and versatility offered by Service Oriented Architecture's (SOA) makes it an ideal approach to use in the rapidly changing mobile environment. However, the mobile setting presents a set of new challenges that service discovery methods developed for nonmobile environments cannot address. The requirements a mobile client device will have from a Web service may change due to changes in the context or the resources of the client device. In a similar manner, a mobile device that acts as a Web service provider will have different capabilities depending on its status, which may also change dramatically during runtime. This paper introduces VOLARE, a middleware-based solution that will monitor the resources and context of the device, and adapt service requests accordingly. The same method will be used to adapt the Quality of Service (QoS) levels advertised by service providers, to realistically reflect each provider's capabilities at any given moment. This approach will allow for more resource-efficient and accurate service discovery in mobile systems and will enable more reliable provider functionality in mobile devices

Efficient Approach Towards an Agent-Based Dynamic Web Service Discovery Framework with QoS Support

Abstract. Web services are about the integration of applications via the Web. Hereby, the programming effort should be minimized through the reuse of standardized components and interfaces. One of the fundamental pillars of the Web service vision is a brokerage system that enables services to be published to a searchable repository and later retrieved by potential users. One of the subtasks in a service-oriented architecture is service discovery. Service discovery, the identification of existing Web Services that can be used by new Web applications, is one of the most critical problems deterring Web Service (WS) technology. Current solution is based on UDDI catalogue browsing that supports only primitive matching mechanisms and provides no control over the quality of registered services Quality of Service (QoS) is becoming an important criterion for selection of the best available service. Currently the problem is twofold. The Universal Description, Discovery and Integration (UDDI) registries do not have the ability to publish the QoS information, and the authenticity of the advertised QoS information available elsewhere may be questionable. We aim to refine the discovery process through designing a new framework that enhances retrieval algorithms by combining syntactic and semantic matching of services with QoS. We propose a model of QoS-based Web services discovery that combines an augmented UDDI registry to publish the QoS information and a reputation manager to assign reputation scores to the services based on customer feedback of their performance. The Certifier verifies the QoS claims from the Web service suppliers. A discovery agent facilitates QoS-based service discovery using the reputation scores in a service matching, ranking and selection algorithm. The novelty of our model lies in its simplicity and in its coordination of the above mentioned components. The Proposed framework should give Web services consumers some confidence about the quality of services of the discovered Web services

A Review on Framework and Quality of Service Based Web Services Discovery

Selection of Web services (WSs) is one of the most important steps in the application of different types of WSs such as WS composition systems and the Universal Description, Discovery, and Integration (UDDI) registries. The more available these WSs on the Internet are, the wider the number of these services whose functions match the various service requests is. Selecting WSs with higher quality largely depends on the quality of service (QoS) since it plays a significant role in selecting such services. In achieving this selection of the best WSs, the potential WSs are ranked according to the user’s necessities on service quality. In many cases, the value of QoS ontology is realized by its support for nonfunctional features of WSs. This ontology is also capable of providing solutions to the interoperability of QoS description. Moreover, based on the QoS ontology, it becomes more possible to develop a framework of semantic WS discovery. The framework enhances the automatic discovery of WSs and can improve the users’ efficiency in finding the best web services. Thus, Web Services are software functionalities publish and accessible through the Internet. Different protocols and web mechanism have been defined to access these Services

Extending Web Service Architecture with a Quality Component: Web Service Architecture and Quality Component

The Web service technology provides standard mechanisms for describing the interface of the services available on the Web, as well as protocols for locating such services and invoking them. Each Web service has an associated Web Services Description Language (WSDL) document which describes how it works and how to invoke it. Such document is registered at a Universal Description, Discovery and Integration (UDDI) registry that provides a discovery service for the WSDL descriptions. The Web services architecture consists of three components: Service Provider, Service Requester and UDDI Registry, and the interactions between them through publish, find, and bind operations. Between finding and binding steps there is another crucial step, which is not fully considered by current approaches. This is the step of selection. The UDDI service registry hosts hundreds of similar Web services, which makes it difficult for the service requesters to choose from them, as the selection is based on the functional properties only. However, many similar services are differentiated by their quality criteria. Therefore, quality criteria are important to be considered in the web service selection. This thesis proposes a quality-based Web service architecture (QWSA) that extends the current Web service architecture with a quality server. The quality server consists of four main components: quality manager, quality matchmaker, quality report analyzer, and quality database. The main purpose of quality server is to assist service requester to select the best available service that fulfils his/her preference by matching between a service requester’s quality requirement and the service providers’ quality specifications. In addition, this thesis reports the development of a quality matchmaking process (QMP) based on the proposed architecture by building a quality service selection system (QSSS). This QSSS has been verified and validated using a case study of Amazon E-commerce service (ECS)

A decision support system for QoS-enabled distributed web services architecture

Service selection is crucial for fulfilling the requirements of service requestors. While in the real service-oriented environment, Quality of Services (QoS) is one of the greatest concerns for consumers during service selection. Existing web services "standards do not tackle the QoS issue adequately when service discovery and selection are performed. In this paper, we argue that the process of services selection is a kind of decision making" to decide which service should be selected dependent on their QoS and trustworthiness values as well as their functional capabilities. Hence, we propose a service selection solution which utilizes the Decision Support Systems Module (DSS Module) to select the most appropriate service. In DSS module we introduce Service Trust to carry out the service QoS measurement based on the Context-specific Quality Aspects. The architecture of DSS module is presented in detail and the solution is also integrated into one of the components "domain broker" in our proposed distributed web services architecture. The contributions of this paper are two fold. Firstly, we apply DSS module into web services, thus opening a new, fertile ground for DSS research in web services literature and secondly, we provide a novel and feasible solution for QoS-based service selection

Towards a Unifying View of QoS-Enhanced Web Service Description and Discovery Approaches

The number of web services increased vastly in the last years. Various providers offer web services with the same functionality, so for web service consumers it is getting more complicated to select the web service, which best fits their requirements. That is why a lot of the research efforts point to discover semantic means for describing web services taking into account not only functional characteristics of services, but also the quality of service (QoS) properties such as availability, reliability, response time, trust, etc. This motivated us to research current approaches presenting complete solutions for QoS enabled web service description, publication and discovery. In this paper we present comparative analysis of these approaches according to their common principals. Based on such analysis we extract the essential aspects from them and propose a pattern for the development of QoS-aware service-oriented architectures

Efficient Retrieval of Web Services Using Prioritization and Clustering

WEB services are software entities that have a well defined interface and perform a specific task. Typical examples include services returning information to the user, such as news or weather forecast services. A web service is formally described in a standardized language (WSDL). The service description may include the parameters associated with web services like input , output and quality of service. As web services and service providers proliferate, there will be a large number of candidate, and likely competing, services for fulfilling a desired task. Hence, effective service discovery mechanisms are required for identifying and retrieving the most appropriate services. The main contributions of our paper are summarized as follows; we propose and implement a method for determining dominance relationships among service advertisements that simultaneously takes into consideration multiple PDM criteria. We introduce a method for prioritization and clustering web services based on similarity measures using efficient algorithms Keywords : Web Service , PDM , dominance score ,TKDD, clustering

Comparison of web service architecture based on architecture quality properties

Web service research has been focused on the issues of automatic binding, performance, scalability, and security, however, little research has been done in evaluation of web service architectures, namely Broker based. Examples of these are Matchmaker Broker, Layered Matchmaker, Facilitator, Layered facilitator, and Peer to peer (P2P) based, such as P2P Discovery, Match Maker and P2P, Split Code and P2P execution, Mobile Code with P2P etc. Another consideration is its impact on the adoption in distributed Internet environment. In this paper we introduce a methodology for measuring and evaluating web service architecture style, and we present our development of a set of architectural quality properties, and use these quality properties to carry out comparison and contract of current web services architectures. We provide a detailed analysis and critique of these, and these could be served as a guidelines for the next generation of web services development, which could adopted into the distributed environment

Web service management system for bioinformatics research: a case study.

In this paper, we present a case study of the design and development of a Web Service management system for bioinformatics research. The described system is a prototype that provides a complete solution to manage the entire life cycle of Web services in bioinformatics domain, which include semantic service description, service discovery, service selection, service composition, service execution, and service result presentation. A challenging issue we encountered is to provide the system capability to assist users to select the "right" service based on not only functionality but also properties such as reliability, performance, and analysis quality. As a solution, we used both bioinformatics and service ontology to provide these two types of service descriptions. A service selection algorithm based on skyline query algorithm is proposed to provide users with a short list of candidates of the \best" service. The evaluation results demonstrate the eciency and scalability of the service selection algorithm. Finally, the important lessons we learned are summarized and remaining challenging issues are discussed as possible future research directions