Web Services Composition Methods and Techniques: A Review <s> INTRODUCTION <s> The goal of the Web Service Composition (WSC) problem is to find an optimal "composition" of web services to satisfy a given request using their syntactic and/or semantic features, when no single service satisfies it. In this paper, in particular, we study the WSC problem from semantic aspects, exploiting the supertype-subtype relationship among parameters, and propose a novel solutionbased on techniques for the boolean satisfiability problem (SAT). Given a set of web service descriptions and a requirement web service, we reduce the WSC problem into a reachability problem on a state-transition system, and then we find the shortest path for the reachability problem, which is amount to the optimal composition. A preliminary experiment using 7 examples reveals that our proposal can find optimal compositions of web services efficiently. <s> BIB001 </s> Web Services Composition Methods and Techniques: A Review <s> INTRODUCTION <s> The automatic discovery and composition of Web services rely on the facilities offered by the providers of services in describing the functionalities of their services semantically and on the description of the client's requests and their needs, without being ambiguous. In this paper, we present a model of Semantic Annotations for Web Services Discovery and its Composition. The proposed approach uses an inter-connected network of semantic Web services describing in OWL-S, using the similarity measure (outputs-inputs similarity) between concepts based on ontology, built before any submitted request. In only one exploration, the composition algorithm can find several composition plans. But the selected composition plan must be ''the best one'' according to the quality criteria (similarity, time and memory space). This technique takes advantages from a graph structure, chaining algorithm of expert system and semantic annotations. <s> BIB002 </s> Web Services Composition Methods and Techniques: A Review <s> INTRODUCTION <s> Web Services are interfaces that describe a collection of operations that are network-accessible through standardized web protocols. When a required operation is not found, several services can be compounded to get a composite service that performs the desired task. To find this composite service a search process in a, generally, huge search space must be performed. The algorithm that composes the services must select the adequate atomic processes and, also, must choose the correct way to combine them using the different available control structures. In this paper a genetic programming algorithm for web services composition is presented. The algorithm has a context-free grammar to generate the valid structures of the composite services and, also, it includes a method to update the attributes of each node. Moreover, the proposal tries to minimize the number of services, and looks for compositions with the minimum execution path. A full experimental validation with four different repositories with up to 1,090 web services has been done, showing a great performance in all the tests as the algorithm finds a valid solution with a short execution path. <s> BIB003 </s> Web Services Composition Methods and Techniques: A Review <s> INTRODUCTION <s> Abstract Various fishery information systems have been developed in different times and on different platforms. Web service application composition is crucial in the sharing and integration of fishery data and information. In the present paper, a heuristic web service composition method based on fishery ontology is presented, and the proposed web services are described. Ontology reasoning capability was applied to generate a service composition graph. The heuristic function was introduced to reduce the searching space. The experimental results show that the algorithm used considers the services semantic similarity and adjusts web service composition plan by dynamically relying on the empirical data. <s> BIB004
Service Oriented Architectures (SOA) and Web Services are presented in the mainstream scientific and industrial for many years. SOA is an architectural paradigm and interactions or patterns between them for components of a system. In this architecture, service is a contractually defined behavior that can be implemented and provided by a component for by using another component  . Web service is a [2] . software component that takes the input data and produces the output data. Web services are loosely coupling that allows developers to create, generate and compose them at runtime, interfaces that describe a collection of operations that are network-accessible through standardized web protocols and its features are described by using a standard eXtensible Markup Language (XML)-based language. However, Web Services are syntactically usually and described with standards such as Simple Object Access Protocol (SOAP), Web Service Description Language (WSDL) and Universal Description Discovery and Integration(UDDI)) BIB004 . The description of web service consists of the technical parameters, constraints and policies that define the terms to invoking service  .. A web service is defined as a four-tuple WS= (name, des, In, Out), name represents service name and is used as a unique identifier; des represents the description of service; In represents the input parameters set of service; and Out represents the output parameters set of service. The SOAP is a protocol to exchanging structured information in a decentralized and distributed environment. WSDL is a XML format for describing the web services and only describes the syntactic interface of web services that alone cannot be used for automatic composition of web services. Thus, semantic standard protocols such as WSDL-S (Web Service Description Language-Semantic), WSMO (Web Service Modeling Ontology), OWL-S (Ontology Web Language -Service) and SAWSDL (Semantic Annotations for Web Service Description Language) have been developed for the automatic web service composition and also UDDI is a virtual registry that exposes information about Web services BIB002 . In many cases, atomic web service isn't sufficient to achieving complex needs of the user. Therefore, web services composition is appropriate solution to finding an optimal composition of web services to satisfy various user requests using their syntactic and/or semantic features BIB001 [6] BIB003 . The rest of this paper is organized as follows: Section II describes preliminary knowledge and background for following discussion. Section III we provide a review of some approaches and current methods and then we categorized all these approaches with respect to some service composition requirements. Finally, Section IV sums up the conclusion.