A Three-Level Semantic Categorization Scheme of Web Services (Short Paper)

Services are an increasingly important part of the Web, and they are a necessary component of the Semantic Web. Semantic Web Services (SWS) are a research effort towards automation of the use of Web services, enhancing existing SOA capabilities with intelligent and automated integration. Recently, we have introduced WSMO-Lite, a lightweight service ontology intended for semantic annotations of the Web Service Description Language WSDL. In contrast to preceding SWS frameworks such as OWL-S and WSMO, WSMO-Lite simplifies the semantic descriptions and enables bottom-up semantic annotation of Web services, but very importantly, it also relaxes the requirements on completeness of semantic descriptions, which enables building incremental layers of semantics on top of existing service descriptions. In this work, we describe various useful subsets of the extent of semantic annotation on Web services with respect to the requirements of SWS automation tasks; and we detail the means of validating SWS descriptions with flexible levels of strictness.

Web services are software components that were designed to improve interoperability and integration of applications developed on different platforms. Automatic Web service composition and dynamic service discovery and selection are the most promising features that can be provided by Web services. These features can be achieved by adding semantics to the different layers of the Web service conceptual stack. The semantic information is provided by ontologies. This paper proposes an ontology model which allows semantic annotation of Web services aiming at automatic Web service composition for food chain traceability. The proposed model consists of a core ontology and two categories of taxonomic trees: Business service description trees and business product description trees. The model has been implemented in the framework of the Food-Trace project for traceability in the domain of meat industry.

Service-orientation for the development of complex distributed systems with reusable components (services) has proved to be highly beneficial approach in software engineering. In order to realize its advantages automated techniques and tools for finding services, selecting the ones that match requestor needs, composing them for achieving enhanced functionality and resolving heterogeneity issues are required. Adding semantics to web services has become the key approach for the automation of service-orientation environments. Current paper proposes semantic approach for service selection and integration. It considers the semantic description of web services and involves reasoning on a knowledge base. The proposed approach for web service discovery and integration is based on designing logic based techniques for matching goal description with the semantic annotation of web services. It provides for the automation of web service search which facilitates the design of practical applications in service-oriented environment.

Description logic is used as the formal theoretical foundation of semantic web services, the paper analyzed description language of Semantic Web Services OWL-S, WSDL-S, WSML and SWSL. Give a formal definition of description about semantic web services, further Web services is interpreted with the semantic of description logic. The satisfiability and subsumption in description logic can be applied to inferring semantic web services. For further research semantic annotation of web services, relation between web services and services, reasoning problems for semantic web services, our work was important and fundamental.

Currently proposed Semantic Web Services technologies allow the creation of ontology-based semantic annotations of Web services so that software agents are able to discover, invoke, compose and monitor these services with a high degree of automation. The OWL Services (OWL-S) ontology is an upper ontology in OWL language, providing essential vocabularies to semantically describe Web services. Currently OWL-S services can only be developed independently; if one service is unavailable then finding a suitable alternative would require an expensive and difficult global search/match. It is desirable to have a new OWL-S construct that can systematically support substitution tracing as well as incremental development and reuse of services. Introducing relationship (IR) into OWL-S is a natural solution. However, OWL-S, as well as most of the other currently discussed formalisms for Semantic Web Services such as WSMO or SAWSDL, has yet to define a concrete and self-contained mechanism of establishing relationships among services, which we believe is very important for the automated annotation and discovery of Web services as well as human organization of services into a taxonomy-like structure. In this paper, we extend OWL-S with the ability to define and maintain relationships between services. Through the definition of an additional inheritance profile, relationships can be stated and reasoned about. Two types of IRs are allowed to grant service developers the choice to respect the contract between services or not. The proposed framework has also been implemented and the prototype will be briefly evaluated as well.

The current Web service technology brought a new potential to the Web of services. However, the success of Web services still depends on resolving three fundamental challenges, namely search, integration and mediation. In this paper we define an extended Web service stack enabling total or partial automation of web service provisioning process. With the goal of a maximal Web standards compliance, we describe various types of service semantics, use RDF Schema (RDFS) to define a pragmatic meaning for those descriptions, and use Semantic Annotations for WSDL and XML Schema (SAWSDL) to define a place for a semantic description in a Web service. We elaborate on the existing SAWSDL specifications and define precise rules for semantic annotations of Web services.

The automatic composition of Web Services has been explored in the literature from different standpoints. It aims to create an execution plan for the flow of Web Services based on requests made and sent by the client, by following the stages necessary for the generation of composite services and then carrying out the execution of the workflow that has been designed. However, no research studies have been found that undertake the whole process of an automatic composition and execution, from the user's request to the execution of the services chosen as a solution. Therefore, the goal of this paper is to evaluate the performance of an automatic Web Service composition, since the request made by the client, to the delivery of the results of the executed composition. This article examines the integration between two tools, the automatic web service composition system and the extensible platform to evaluate semantic web services with the aim of conducting a performance evaluation of an entire process of automatic composition of Web services.

RESTful Web service composition with BPEL for REST

A metamodel-based definition of a conversion mechanism between SOAP and RESTful web services

The need for adaptability in software is growing, driven in part by the emergence of autonomic computing. In many cases, it is desirable to enhance existing programs with adaptive behavior, enabling them to execute effectively in dynamic environments. Existing web service invocation and adaptation mechanisms are limited only to the scope of web service choreography in terms of web service selection. Such a scope hardly leaves ground for a participating service in a choreographed flow to re-adjust itself in terms of changed non functional expectations. In this paper we used Aspect oriented programming (AOP) to invoke Web Services (WS) and Representational State Transfer (REST) web services and to enable dynamic adaptation in existing programs. We propose an approach to implement dynamic adaptability especially in Aspect weaving at the time invoking web services and REST web service. We have used AspectJ; Java based language to create aspects in Eclipse supported framework.

Service Oriented Architecture (SOA) has been widely adopted by industries due to its ability to provide increased interoperability among heterogeneous systems. SOA is realized through web services which can be either based on the style of Remote Procedure call(RPC) and SOAP protocol or on the Representational State Transfer(REST) style and HTTP. RESTful web services are increasingly becoming popular in the industry because of their simplicity, uniform interface, statelessness and cacheability benefits. The ability to efficiently select and integrate appropriate heterogeneous services available on the web dynamically at runtime is essential in the development of the applications based on web services. Whenever a single web service cannot satisfy the functionality required by the user, there should be a possibility to combine several existing services together in order to fulfill the request. This need has triggered a considerable number of research efforts on the composition of web services. Although several works have focused on the composition of SOAP based web services, there has not been adequate effort towards the composition of RESTful services. However, due to the above- mentioned advantages offered by the RESTful web services, it will be beneficial to design an application as a composition of such RESTful services. Towards this objective, this paper investigates two different approaches for composing the REStful web services specifically designed for health care domain, one using the Jopera tool and another using hypermedia.

A difficulty of sharing messages transferred among Web services is absence of common vocabulary, and the semantic organization and description of Web services is an important requirement for enabling the automatic discovery, selection, composition, execution and monitoring of Web services. This paper proposes a model for semantic-based interaction between Web services. The method defined some ontology-based vocabularies to describe different Web services and some mapping rules among those vocabularies. Compared with existing methods, the method considers the Web services together with the semantic interpretation, satisfiability and reasoning of distributed ontologies. So the method can ensure the share and reusage of term be used for describing parameters of Web services.

New value-added business, generated by Web service composition in BPEL, provides more powerful and flexible features. SOAP-based web services invoked in BPEL are heavy with redundant information and lower performance. RESTful Web service is brought forward to new value-added business as an alternative solution. However, it's a big challenge to compose RESTful Web services with SOAP-based Web Services in SOA BPEL business processes. BPEL is not designed to use RESTful Web services because these types of services do not use WSDL to describe themselves. This paper proposes a novel approach for integrating RESTful Web services and SOAP-based Web services in business processes described in BPEL. The approach is applied to a practical multimedia conference BPEL process, and the experimental data show the stability of the new RESTful BPEL process with a higher performance.

This paper presents a novel approach for Web Service Retrieval that utilizes Latent Semantic Indexing method to index both SOAP and RESTful Web Services. Presented approach uses modified term-document matrix that allows to store scores for different service components separately. Service data is collected and extracted using web crawlers. To determine similarities between user query and services the cosine measure is used. Presented research results are compared to standard Latent Semantic Indexing method. We also introduce our Web Service test collection that can be used for many benchmarks and make research results comparable.KeywordsLatent Semantic IndexingWeb Service RetrievalWeb Service

Despite increasing availability of Web Services (WS), their automatic processing (classification, grouping or composition) slows down because of the difficulty to read the WSDL service descriptions without related technical knowledge. Categorizing services for automatic service discovery and composition has become a challenging problem. The paper argues that n-gram representation of the data extracted from the different sections of the WSDL description (types, messages and operations) along with the weighing scheme can benefit the classification of services. Experiments are carried out with three different classifiers over available collections of WS descriptions. It is shown that such representations as word bigrams or letter trigrams extracted from WSDL Operations and Types service description features with TF-IDF as n-gram weighting scheme, can improve automatic WS classification.