The PORSCE II framework: using AI planning for automated Semantic Web service composition

Web services have emerged as a major technology for deploying automated interactions between distributed and heterogeneous applications. The main advantage of Web services composition is the possibility of creating value-added services by combining existing ones to achieve customized tasks. How to combine these services efficiently into an arrangement that is both functionally sound and architecturally realizable is a very challenging topic that has founded a significant research area within computer science. A great deal of recent Web-related research has concentrated on dynamic Web service composition. Most of proposed models for dynamic composition use semantic descriptions of Web services through the construction of domain ontology. In this paper, we present our approach to dynamically produce composite services. It is based on the use of two Artificial Intelligence (AI) techniques: Case-Based Reasoning (CBR) and AI planning. Our motivating scenario concerns a national system for the monitoring of childhood immunization.

Semantic Web Service technology provides a strong support for automation software development based on Web service. By analyzing the existing description models and methods of semantic Web service, a Semantic Web Service Description Model (WSDM4S) and its formal description based on SHOIN+(D) are proposed, which attempt to offer an effective model for description, publication, discovery, composition, and execution of Web services based on semantic description. And a Semantic Web Service Description Language (WSDL4S) based on XML is designed to support the WSDM4S. Based on WSDL4S, Web Services could be packaged into basic semantic unit of semantic software development.

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.

Ontologies as a means for semantic description of web services have been discussed for many years. Various formal languages and correspoding tools using ontologies for describing web services have also been proposed (i.e. OWL-S). However, these existing approaches mainly are targeting domain experts creating ontologies. They are often too complex to be used by an average service provider offering web services online. But for offering and retrieving web services from future electronic marketplaces or service registries, a semantic service description is necessary. Therefore, in this paper an approach for an easy-to-use web-based editor for describing web services using ontologies based on the OWL-S language is proposed and evaluated. It not only supports a semantic, but also a commercial description of the web service offered, while remaining compatible with previous approaches addressing such holistic web service descriptions.

This paper presents a new approach for automatic Web service composition based on the formalism of Fluent Calculus using semantic Web service descriptions. In our approach, the Web service composition process is viewed as an AI planning problem in the Fluent Calculus formalism. To semantically describe Web services, we have used a Web service domain ontology which is then translated into a Fluent Calculus knowledge base, necessary for the composition planning phase. For verifying the composed services, the Label Transition System Analyzer (LTSA) formalism is used. The paper also presents an experimental prototype for the Fluent Calculus based Web service composition and demonstrates its effectiveness with the help of an application scenario from the social event planning domain.

Service-oriented computing is gaining wider acceptance. For Web services to become practical, an infrastructure needs to be supported that allows users and applications to discover, deploy, compose and synthesize services automatically. For this automation to be effective, formal semantic descriptions of Web services should be available. In this paper we formally define the Web service discovery and composition problem and present an approach for automatic service discovery and composition based on semantic description of Web services. We also report on an implementation of a semantics-based automated service discovery and composition engine that we have developed. This engine employs a multi-step narrowing algorithm and is efficiently implemented using the constraint logic programming technology. The salient features of our engine are its scalability, i.e., its ability to handle very large service repositories, and its extremely efficient processing times for discovery and composition queries. We evaluate our engine for automated discovery and composition on repositories of different sizes and present the results.

The article describes a method for developing and modelling composite web-services. Web-service composition is used to derive new functionality from the interaction of existing web-services. Composite web-services are built in several stages: specifications (determining the type of service); development of the structure of the service based on the algebra of services; service composition modelling; selecting a service variant and generating a service. The main elements of the proposed approach are the algebra of services and web-services interaction models (basic and composite). The above approach formally presents the consideration of the main aspects in solving problems related to the construction of effective composite web-services and the selection of mathematical models, namely: description of web-services, determining the structure of web-services, taking into account the dynamics of information changes, taking into account the main uncertainties in building the structure web-services. Based on the approach, a method for constructing composite web-services has been developed. The method is based on an algebraic description of a web-service based on a specialized algebra of services. The method consists of the following steps: description of the task of developing a web-service; development of the structure of a web service based on the algebra of services; formal description of the structure and clarification of service operations; building models of functioning and interaction of service components; building simulation models of the composite service; defining the final structure of the composite service; web-service implementation. The main tool for describing composite services is the algebra of services, and the model building tool is colouredPetri nets implemented using СPN Tools. As an example of the application of the developed method, the construction of a pharmaceutical service is described, in which the modellingof the interaction of web-services based on Petri nets is used. The process of building a composite model of a web-service is considered. The process begins with building a pharmaceutical web-service model structure based on the service algebra. Based on the service algebra, operators were developed to implement composite services. The structure of the model is developed, which is presented in the form of a formal description. The process of building pharmaceutical service models in the СPN Tools environment is described in detail.

A web service is a software system that supports interoperable machine to machine interaction over the network. It can be any kind of service provided on the web that can exchange data between applications. In simple terms, it is any program that is callable by another program across the web using standard protocols. Web services are special because they are independent of the platform, programming language, and model design. In current web applications, more businesses are gradually publishing their business as services over the web. This growing number of web services available within an organization and on the Web raises a new and challenging search problem: locating desired web services. Searching for web services with conventional web search engines is insufficient in this context. In this paper, a latent semantic web service discovery and composition framework, addressing both discovery and composition of web services, is introduced. The framework provides a graphical visualization interface that can facilitate users in finding the desired web service beyond the general keyword search and provide composition of complex services if the service does not exist. A novel approach based on an information retrieval technique known as latent semantic analysis is applied to a large web service descriptions data set collection. By using co-occurrence patterns across the entire data collection, and then using those patterns to infer semantic relationships between documents, relevant results in a ranked order can be retrieved. Moreover, a back to front algorithm is applied to the composition search interface in order to compose complex web services in full or partial terms from pre-existing web services when the requested service does not exist. An experimental study conducted on a collection of 2525 publicity available web service shows improved performance to the technique applied in obtaining much better search results.

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.

This article tackles the problem of supplying the low level commanders with information from information sources located on higher command levels, distributed using web services, the most commonly used technology in modern command and control systems. There has been proposed the Adaptation Framework For Web Services Provision (AFRO) that defines a mechanism for effective web services invocation in tactical networks, which are considered disadvantaged in terms of available throughput, delay and error rate. Its implementation, in the form of AFRO Proxy performs so called adaptation actions, which are modifications of the SOAP XML messages by changing their encoding to more efficient or dropping information that are accepted to be removed by the service requester. The proposed adaptation mechanism gives promising effects for low level commanders located at the battlefield. They can be supplied with information generally available on high command levels, which, up to now, were very rarely distributed to tactical networks.

There are many studies on composing Web services by creating service chains to get valid Web service compositions, but in practical application, some Web services can work in parallel This paper proposes a new composing Web service method based on chaining Web service units, it adds domain ontology labels of input and output to the description of a Web service, and uses the output similarity measure to find all related Web service units for a user request automatically. It builds Web service unit chains by reverse depth-first searching over the semantic relation graph of Web services, those Web service unit chains whose output similarity is bigger than predefined threshold and the inputs are only provided by the user request are candidate Web service compositions.

One of the main visions of Semantic Web has been the ability of software agents to compose atomic web services in order to facilitate the automation of complex tasks. One of the approaches used in the past in order to automatically construct composite web services has been AI planning. The most important advantage of this approach is its dynamic character that reduces the interference of the user. Although there have been various attempts to utilize planning algorithms and systems in the composition process, there has been little work in the field of converting web service composition plans in OWL-S. This paper studies the use of two well established standards in expressing plans and composite web services, namely the Planning Domain Definition Language (PDDL) and the Ontology Web Language for Services (OWL-S) and suggests a method for translating the produced PDDL plans of any planning system to OWL-S descriptions of the final composite web services. The result is a totally new web service that can later be discovered and invoked or even take part in a new composition.

Aiming at the hot and difficult issues in Web services and service composition, this paper analyzes and studies the selection of Web services and service composition from the functional and non functional attributes of Web services, and mainly makes the following work and innovation. First of all, the functional attributes of Web services are studied, Web services on various service provision platforms are collected, and Web services are classified. Secondly, aiming at the shortcomings of existing Web service QoS attribute evaluation models, an improved method is proposed, which introduces a comprehensive evaluation mechanism of variable weight vector. Based on the constant weight comprehensive evaluation method, the state variable weight vector is established to dynamically adjust the attribute weights of various service QoS indicators, so as to improve the accuracy and objectivity of the Web service QoS attribute evaluation. Finally, in view of the defects and deficiencies of traditional algorithms in the selection of Web service composition, the particle swarm optimization algorithm with linearly decreasing inertia weight and learning factor is introduced, which better balances the self cognition and social learning ability of particles, and improves the search speed and global search ability of particles. And a large number of experiments are carried out to compare it with the traditional algorithm, which verifies the effectiveness and superiority of the improved particle swarm optimization algorithm.

Semantic Web Services promise seamless interoperability of data and applications on a semantic level, thus turning the Web from a world-wide information repository for human consumption only to a device of distributed computation. To this end, appropriate semantic descriptions of Web services and intelligent mechanisms working on this need a solid foundation in terms of the underlying semantically-enabled communication technologies. Recent advances in middleware technologies propose semantics-aware tuplespaces as an instrument for coping with the arising requirements of scalability, heterogeneity and dynamism. An additional argument is that Semantic Web Services have inherited the communication model of XML-based Web services, which is based on message exchange, thus being a priori incompatible with the REST architectural model of the Web. Analogously to the conventional Web, truly Web-compliant service communication should be based on persistent publication instead of message passing. In this chapter, we present “Triple Space computing”, a Triple Space-based coordination middleware for Semantic Web Services. We take a closer look at the respective data, infrastructure and coordination models that enable the management of formal knowledge and that support the interaction patterns characteristic for the Semantic Web and Semantic Web Services. Applying Triple Space computing to Semantic Execution Environments and Service-Oriented Infrastructures is the second main topic of this chapter.

Web service matching is an important component of web service system architecture. The recall and precision rate of traditional web service matching methods is usually not satisfactory. Semantic description of web service using ontology provides a way for service matching on semantic level. The chapter proposes an approach for semantic web service matching. Experimental results show that the proposed method can improve the recall and precision rate effectively.