IJRIT International Journal of Research in Information Technology, Volume 1, Issue 5, May 2013, Pg. 196-201

International Journal of Research in Information Technology (IJRIT)

www.ijrit.com

ISSN 2001-5569

A survey on Web Service Composition Algorithm 1

Bhavin P Mistry, 2 Kirit J Modi

1

Department of Information Technology, U V Patel College of engineering, Kherva, Mehsana, Gujarat, India-384012 2 Department of Information Technology, U V Patel College of engineering, Kherva, Mehsana, Gujarat, India-384012 1

[email protected] , 2 [email protected]

Abstract Service Oriented Computing (SOC) is an emerging cross-disciplinary paradigm for distributed computing that is changing the way, of how software are designed, architecture, delivered and consumed. Web Services are the most promising part of SOC. Web Services are autonomous, platform-independent, computational element that can be described, published, discovered, orchestrated and programmed using XML. Web Service Composition plays an important role in SOC. Web Service Composition may be dynamic or static. A composition process require an algorithm to perform composition task. Now-a-days various approach for composition algorithm are used as required by research task. Popular approach are an uninformed search, a greedy informed search and a genetic algorithm etc. In this study, we have done a survey on various composition algorithm and derive their features and capabilities for composition.

Keywords: Web Service Composition, SOC, Web Service, Semantic Web, Algorithm

1. Introduction A Web Service can be defined as a piece of software that conforms to a set of open interoperability standards [1] such as WSDL (Web Service Description Language), SOAP (Simple Object Access Protocol), and UDDI (Universal Description, Discover and Integration), for Description, messaging protocol and discovering, respectively. In a Service Oriented Architecture (SOA), application can be accomplished by composing simple services in order to perform a given task. The necessity for fast service composition systems is directly connected with the emergence of Service Oriented Architecture (SOA). Today, companies depend on complex IT infrastructure that require frequent changes in their business strategy. A SOA is an ideal option for this type of architecture. Sematic Web is the next generation Web Technology that can provide more user specific description in Web Service. In traditional Web Service Technology, there is a lake of Semantics. A Semantic Web Service (SWS) is a Bhavin P Mistry, IJRIT

196

service whose input, output, precondition and effects (IOPE) are associated with a formal description rather than just a data type. The advantage of Semantic Web Service is that it can provide more functionality than cannot be provided by traditional services. It can automatically match and compose functionality provided by other service when only one service is not able to produce the desired functionality. For Web Service Composition various approaches and algorithms are used based on research task. Some algorithm is based on informed approach, some are based on uninformed approach and some are based on genetic approach. But some algorithms have lake of service discovery strategy, do not use semantic approach etc. In Web Service Composition an Algorithm is a key element that perform important task of composition process.

2. Web Service Web Services are considered as self-contained, self-describing, modular applications that can be published, located and invoked across the Web [2]. Today, all business are run on heterogeneous environments. They require cross-platform application integration over the Internet. If one service is not able to fulfill the requirement of user, then there should be possibility to combine existing services together in order to fulfill the request. A Web service paradigm is typically supported by set of standards. For example, the industry standards include Simple Object Access Protocol (SOAP) for message exchange; Web services Description Language (WSDL) for Web service description, and Universal Description, Discovery, and Integration (UDDI) for Web service discovery and integration.

Fig. 1 Web Service Model [3]

As depicted in Fig. 1, there are three roles in the Web service architecture [3]: the service provider, consumer, and service registry. Interactions among these roles include service publishing, finding, binding, and invocation. A Web service provider publishes a Web service defined by WSDL in a service registry (e.g., UDDI). A service consumer can search and retrieve a service description and the access point to a WSDL file from the registry. The WSDL file is then used to generate a client-side Web service proxy that is used by the service consumer to invoke the Web service by sending a SOAP message. After the service is executed, the results will be returned to the

Bhavin P Mistry, IJRIT

197

service consumer as a SOAP message. SOAP enables communication between two applications that are developed in different programming languages and run on different platforms.

3. Semantic Web Semantic web services are built around universal standards for the interchange of semantic data, which makes it easy for programmers to combine data from different sources and services without losing meaning. Web services can be activated "behind the scenes" when a web browser makes a request to a web server, which then uses various web services to construct a more sophisticated reply than it would have been able to do on its own. Semantic web services can also be used by automatic programs that run without any connection to a web browser. A Semantic Web Services platform that uses OWL (Web Ontology Language) to allow data and service providers to semantically describe their resources using third-party ontologies is SSWAP: Simple Semantic Web Architecture and Protocol [4]. The goal of semantic Web is to develop enabling standards and technologies designed to help machines understand more information on the Web and support richer discovery, data integration, and automation of tasks. The layers of Semantic Web are shown in Fig. 2

Fig. 2 Semantic Web Stack [5] The main layer of semantic Web architecture is ontology vocabulary, which typically consists of hierarchical distribution of important concepts in a domain, along with descriptions of the properties of each concept. RDF+rdfschema layer is a knowledge representation language, providing basic elements for the description of ontologism. Ontologism play a pivotal role in the semantic Web by providing a source of shared and precisely defined terms that can be used in metadata. The recognition of the key role in ontologism is likely to play in the future of the Web that has led to extension of Web markup languages like XML Schema, RDF and RDF Schema.

Bhavin P Mistry, IJRIT

198

The recognition of the limitations in markup languages led to the development of new Web ontology languages such as OIL, DAML–ONT and DAML+OIL, OWL. In Proof layer, the ultimate goal of semantic Web is to create a much smarter content which could be understood by the machines. Trust is the top most layer of the semantic Web architecture in which the trustworthiness of information should be subjectively evaluated by each information consumers. Digital signatures run horizontal to the RDF family up through the proof layer and support the notion of trust. Semantic Web services will allow the semi-automatic and automatic annotation, advertisement, discovery, selection, composition, and execution of inter-organization business logic, making the Internet become a global common platform where organizations and individuals communicate among each other to carry out various commercial activities and to provide value-added services. The idea and vision of the “Semantic Web” [6] catches on and researchers as well as companies have already realized the benefits of this great vision. Ontologies [7] are considered the basic building block of the Semantic Web as they allow machine supported data interpretation reducing human involvement in data and process integration.

4. Web Service Composition Web Service Composition plays an important role in SOC. There are several standards available to support Web Service Composition like SOAP, BPEL4WS etc. Web Service Composition may be dynamic or static. Now-a-days, Dynamic Web Service Composition is interesting topic among researcher. The mainstream XML standards for interoperation of web services specify only syntactic interoperability, not the semantic meaning of messages. For example, Web Services Description Language (WSDL) can specify the operations available through a web service and the structure of data sent and received but cannot specify semantic meaning of the data or semantic constraints on the data. This requires programmers to reach specific agreements on the interaction of web services and makes automatic web service composition difficult. Web services are well defined and re-usable software components that perform specific, encapsulated tasks via standardized Web-oriented mechanisms. Simple Web services can be assembled together to perform a more complex Web service.

4.1 Phases of Web Service Composition[2] Most precisely, the process of automatic service composition includes the following phases: 1. 2. 3. 4. 5.

Presentation of single service Translation of the languages Generation of composition process model Evaluation of composite service Execution of composite service

Bhavin P Mistry, IJRIT

199

5. Web Service Composition Algorithm In [8], three different approaches for service composition are proposed. An uniformed approach, which is based on a Depth-First Search, an informed approach, which is based on a heuristic that guides the composition process, and a generic approach, which is based on evolutionary approach, which is based on evolutionary algorithm.

Author M. A. Amiri,H. Serajzadeh [9]

Approach Genetic based Algorithm

Description Here author has proposed new algorithm based on Genetic approach with QoS. They have improved generation of chromosomes, selection and crossover function. So, the speed of algorithm is increased, but computation time is low.

Frederico G.A. and Jose M.P. de Oliveria [10]

Heuristic based runtime ranking (informed)

Here authors have suggested heuristic based run time ranking algorithm with QoS. The ranking composition relies on a heuristic that considers either the functional correctness, or the overall quality of the composite service.

Bin & Jian Wu, S. Deng, Ying Li, J. Yin [11]

State Space Search (informed)

Here authors have proposed enhanced state space search approach with heuristic. They introduce heuristic about domain ontology to improve search space.

Ching-Seh Wu and Ibrahim Khoury [12]

Tree Based Search (informed)

Here authors have proposed a cloud web service composition algorithm. They have used BFS algorithm to search pruned tree in effective and efficient way according to distance evolution function.

Seyyed Vahid Hashemian,Farhad Mavaddat [13]

Graph Based Search (informed)

Here authors have used specific modelling language called Inference Automata. Given a request for a web service, a composite web service as an interface automaton is found which matches that request. The Interface automaton can be converted to a web service that could be published on the web.

Table 1 Web Service Composition Algorithm

6. Conclusion In this paper we have done survey on various web service composition algorithm and describe their functionality regarding composition. Today, web service composition is a well-known research topic among researchers. We have taken some of algorithm for classification purpose and we found that there are mainly three type of algorithms are used for web service composition: uninformed, informed (greedy) and genetic algorithm. In future, we want to do survey on Automatic and Static Web service composition approaches.

Bhavin P Mistry, IJRIT

200

7. References [1] Eric Pulier and Huge Taylor. Understanding Enterprise SOA. Manning Publications Co., Greenwich, CT,USA 2005. [2] Jinghai Rao and Xiaomeng Su. “A Survey of Automated Web Service Composition Methods,” In: Proceedings of the 1st International Workshop on Semantic Web Services and Web Process Composition, SWSWPC2004, LNCS, San Diego, USA,43-54, 2004. [3] K. Gottschalk, S. Graham, H. Kreger, and J. Snell. Introduction to Web services Architecture. IBM Systems Journal, Vol.41, No.2, 170-177, 2002. [4] Damian DG Gessler, Gary S Schiltz, Greg D May, Shulamit Avraham, Christopher D Town, David Grant and Rex T Nelson. “SSWAP: A Simple Semantic Web Architecture and Protocol for semantic web services,” BMC Bioinformatics, 2009. [5] Fan Li. “An Algorithm Concerned Dynamic Composition of Web Services Based on Ontology,” ICIECS, Wuhan, China, pp. 1-4 2009. [6] W3C, W3C Semantic Web Activity, 2013. [Online] http://www.w3.org/2001/sw/ (10 May 2013) [7] Uschold, M. and M. Gruninger. Ontologies: Principles, methods and applications. Knowl-edge Engineering Review, 11(2): pp. 93-155, 1996. [8] T. Weise, S.Bleul, D. Comes, and K. Geihs. “Different approaches to semantic web service composition” In ICIW ’08: Proceedings of the 2008 Third International Conference on Internet and Web Applications and Servicess, pp. 90-96, Washigton, DC, USA, IEEE Computer Society, 2008. [9] Mahmood A.A., H. Serajzadeh. “QoS Aware Web Service Composition Based On Genetic Algorithm,” In IST ’2010: Proceedings of the 2010 Fifth International Symposium on Telecommunications, pp. 502-507, 2010. [10] Frederico G. A. de Oliveira Jr. and Jose M. Parente de Oliveira. “A heuristic- based Runtime Ranking for Service Composition,” IEEE Computer Society, 2009. [11] Bin Wu, Jian Wu, Shuiguang Deng, Ying Li, Jianwei Yin. “Automatic Composition of Semantic Web Services- an Enhanced State Space Search Approach,” Proceedings in 2010 International Conferences on Service Sciences, pp. 226230, 2010. [12] Ching-Seh Wu and Ibrahim Khoury. “Tree Based Search Algorithm for Web Service Composition in SaaS,” Proceedings in 2012 Ninth International Conference on Information Technology- New Generations, pp. 132-138, 2012. [13] Seyyed Vahid Hashemian,Farhad Mavaddat. “A Graph-Based Approach to Web Services Composition,” Proceedings of the 2005 Symposium on Applications and the Internet (SAINT’05), IEEE, 2005.

Bhavin P Mistry, IJRIT

201