Semantic Web Service Composition

Litteratus Calculus is a proposal to help Semantic Web enjoy the good properties which made the success of the original Web, i.e. natural language, navigation, simple search, freedom of formats, without sacrificing the structural and normative qualities of semantics. This poster outlines the underlying formalism of Litteratus Calculus, explains how it relates to Semantic Web standards, and describes some promising experiments. It is an invitation to a shared reflection on these points.

In this essay, we poke at several sacred cows (even though we like their milk and drink it ourselves) and point out several overlooked ordinary cows as well. We discuss our little herd of claims in five sections. Trust-"reliance on the integrity, ability, or character of a person or thing" 1 -is pervasive in social systems. We constantly apply it in interactions between people, organizations, animals, and even artifacts ("Can I trust my car on this vacation trip?"). We use it instinctively and implicitly in closed and static systems, or consciously and explicitly in open or dynamic systems. An epitome for the former case is a small village, where everybody knows everybody, and the villagers instinctively use their knowledge or stereotypes to trust or distrust their neighbors. A big city exemplifies the latter case, where people use explicit rules of behavior in diverse trust relationships. A city dweller builds up trust, for instance, by asking friends or recommendation services for a dependable plumber. If trust is so pervasive and beneficial in complex social systems, why not exploit pervasive trust as a paradigm in computing environments? (Using pervasive trust in nonpervasive computing is not a contradiction!) We already use trust in computing systems extensively, although usually subconsciously. Examples are users' trust-based decisions to search for reputable ISPs or e-banking sites, or to ignore emails from "Nigerians" asking for help transferring millions of dollars out of their country. The challenge for exploiting trust in computing lies in extending the use of trust-based solutions, first to artificial entities such as software agents or subsystems, then to human users' subconscious choices.

Large software systems are modularized in order to improve manageability. The parts of the software system communicate in order to achieve the desired functionality. To better understand, develop, manage, and maintain the resulting complexity, this paper presents a framework of ontologies. The ontologies range from very general, foundational ones to ontologies that elucidate the specificities of particular modularization and communication paradigms. We support two specific paradigms. First, we define an ontology for software components that may be used in traditional middleware architectures, e.g., application servers. Second, we specify an ontology for Web services. Through the reuse of existing foundational ontologies and our new Core Software Ontology, our proposal offers several advantages. In particular, it avoids the typical shortcomings related approaches exhibit and it allows for the concise definition of commonalities and differences of the two paradigms.

Peer-to-Peer systems are a new paradigm for information sharing and some systems have successfully been deployed. It has been argued that current Peer-to-Peer systems suffer from the lack of semantics. The SWAP project (Semantic Web and Peer-to-Peer) aims at overcoming this problem by combining the Peer-to-Peer paradigm with Semantic Web technologies. In the course of our investigations it turned out that the nature of Peer-to-Peer systems requires some compromises with respect to the use of semantic knowledge models. In particular, the notion of ontology does not really apply as we often do not find a shared understanding of the domain. In this paper, we propose a data model for encoding semantic information that combines features of ontology (concept hierarchies, relational structures) with a flexible description and rating model that allows us to handle heterogeneous and even contradictory views on the domain of interest. We discuss the role of this model in the SWAP environment and describe the model as well as its creation and access.

Semantic Web Services are a research effort to automate the usage of Web services, a necessary component for the Semantic Web. Traditionally, Web service discovery depends on detailed formal semantic descriptions of available services. Since a complete detailed service description is not always feasible, the client software cannot select the best service offer for a given user goal only by using the static service descriptions. Therefore the client needs to interact automatically with the discovered Web services to find information about the available concrete offers, after which it can select the best offer that will fulfill the user's goal. This paper shows when and why complete semantic description is unfeasible, it defines the role and position of offer discovery, and it suggests how it can be implemented and evaluated.

A framework for modeling Semantic Web Service is proposed. It is based on Description Logic (DL), hence it is endowed with a formal semantics and, in addition, it allows for expressing constraints in service descriptions of different strengths, i.e. Hard and Soft Constraints. Semantic service discovery can be performed by matching DL descriptions, expressing both Hard and Soft constraints, and exploiting DL inferences. Additionally, a method for solving the problem of ranking services is proposed which is based on the use of a semantic similarity measure for DL. This method can rank (matched) service descriptions on the grounds of their semantic similarity w.r.t. the service request, by preferring those that are able to better satisfy both Hard and Soft Constraints. p ) I |) ) = 5 8 • max( 5 8 , 5 5

Peer-to-Peer systems are a new paradigm for information sharing and some systems have successfully been deployed. It has been argued that current Peer-to-Peer systems suffer from the lack of semantics. The SWAP project (Semantic Web and Peer-to-Peer) aims at overcoming this problem by combining the Peer-to-Peer paradigm with Semantic Web technologies. In the course of our investigations it turned out that the nature of Peer-to-Peer systems requires some compromises with respect to the use of semantic knowledge models. In particular, the notion of ontology does not really apply as we often do not find a shared understanding of the domain. In this paper, we propose a data model for encoding semantic information that combines features of ontology (concept hierarchies, relational structures) with a flexible description and rating model that allows us to handle heterogeneous and even contradictory views on the domain of interest. We discuss the role of this model in the SWAP environment and describe the model as well as its creation and access.

This paper describes how semantic bridges realized in terms of rulebased ontology mappings can be incorporated into BPEL processes. The approach is explained by applying it to a semantic system integration scenario in the eBusiness domain defined as the "purchase order mediation" scenario in the context of the Semantic Web Service Challenge 1 . The presented approach relies strongly on the existing Web standards and is based on widely adopted open source software components.

The Semantic Web Service Challenge is one of the major initiative dedicated to work on Semantic Web Service (SWS) discovery and selection. It represents an effective manner for evaluating the functionality of SWS technologies. In this paper, we provide a new SWS-Challenge scenario proposal with new interesting problems to be solved on the basis of an analysis of a real world shipment scenario in the logistic operators domain. In the discussion a number of aspects concerning the discovery and selection processes are emphasized. In particular, we focus on the problem of considering the heterogeneity between the provider and the requester perspectives, and on the differences between functional and non functional specifications both on the requester and provider side.

This project aims at creating a network of distributed interoperable semantic services for building more complex ones. These services will be available in semantic Web service libraries, so that they can be invoked by other systems (e.g., semantic portals, software agents, etc.). Thus, to accomplish this objective, the project proposes: a) To create specific technology for developing and composing Semantic Web Services. b) To migrate the WebODE ontology development workbench to this new distributed interoperable semantic service architecture. c) To develop new semantic services (ontology learning, ontology mappings, incremental ontology evaluation, and ontology evolution). d) To develop technological support that eases semantic portal interoperability, using Web services and Semantic Web Services. The project results will be open source, so as to improve their technological transfer. The quality of these results is ensured by a benchmarking process.

This article presents the semantic portal MUSEUMFINLAND for publishing heterogeneous museum collections on the Semantic Web. It is shown how museums with their semantically rich and interrelated collection content can create a large, consolidated semantic collection portal together on the web. By sharing a set of ontologies, it is possible to make collections semantically interoperable, and provide the museum visitors with intelligent content-based search and browsing services to the global collection base. The ...

The increase in complexity of integrated circuits results in the need to develop hardware platforms shared among a set of applications in the same domain. Today's general purpose processors cannot satisfy the future aggressive timing and power constraints for a specific application. On the other hand, conventional ASIC design methodologies are costly and require a long time-to-market for today's complex designs. We need a platform based system optimized for a set of applications in a same domain. Reconfiguration has to be integrated into system design. We must exploit the regularity (or similarity) among applications in target system design. This regularity depends on the domain of applications . For example, Each application can demand different set of modules to be embedded as fixed cores in the target system. In this work, we specifically study one of the important issues in domain-specific programmable design methodologies. We introduce the pattern selection problem. Patterns are application specific computational units. The patterns embedded on the target system are selected by exploiting regularity among the applications in the same domain. The number of patterns nominated by applications to be embedded on systems can be large. There can also exist overlap between the patterns. We present a gain model which can represent different characteristics of patterns. Using this gain model, we propose an algorithm to select a set of patterns such that the objective is maximized. Our model and proposed algorithm can be applied at different levels of design hierarchy. Our method also considers the overlap between the patterns. The experimental results show that our method chooses different sets of patterns when area limit for embedded cores on the system changes. We used our method to select a set of embedded modules on the SPS architecture [6] for multimedia applications. Comparing the results obtained by our algorithm with the method in which only common patterns are chosen to be embedded, latency and utilization of embedded patterns can be improved by ¢ £¢ ¥¤ and ¦ £ § £¤ , respectively.

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This paper demonstrates an approach for technology-enhanced learning, combining analysis, collaborative work, mobile learning (m-learning for short), discussion, and learning-by-authoring approaches in order to achieve more active participation of the learners during the reception of knowledge and to stimulate their creative thinking. The learners visit famous churches, monasteries, museums, etc., where they can see samples of Bulgarian Iconography supported by m-learning. They rely on the GUIDE@HAND platform containing personalized collections presenting location, historical data, pictures, etc. Multimedia and other information resources are delivered through the Virtual Encyclopaedia of the East-Christian Art digital library (BIDL)—a web-based environment for registration, documentation, access and exploration of Bulgarian iconographical artefacts. The main goal of the learners is to create their own learning material/project by analysing the available resources. The presented use...

Triple Space Computing (TSC) has been proposed as communication and coordination paradigm based on the convergence of spacebased computing and the Semantic Web. It acts as a global virtual shared space like middleware to enable communication and coordination of semantic data based on the principle of publish and read. This paper presents an overview of the work in progress under Austrian FIT-IT funded TSC project (http:==tsc.deri.at). It presents the evolution of the TSC framework, overall architecture and its usage by Semantic Web Services.

Abstract. Electronic Government initiatives, such as seamless public services delivered at one-stop government portals, require establishing collaborative networks among public-and private-sector organizations. However, semantic interoperability problems emerge as these organizations may differ in the terms and meanings they use to communicate, express their needs and describe resources they make available to each other. This paper describes typical semantic interoperability problems and presents a middleware solution to address ...

Currently available toolsets for the development of embedded systems adopt traditional architectural styles and do not cover the whole requirements of the development process, with extensibility being the major drawback. In this paper, a service-oriented architectural framework that exploits semantic web is defined. Features required in the development process are defined as web services and published into the public domain, so as to be used on demand by developers to construct their projects' specific integrated development environments (IDEs). The infrastructure required to build a web service-based IDE is presented. Specific web services are defined and the way these services affect the development process is discussed. Special focus is given on the device model and the means that such a modelling can significantly improve the development process. A prototype implementation demonstrates the applicability and usefulness of the proposed demand-led development process in the industrial automation domain.

Semantic Business Process Management (SBPM) aims, among other advantages, to facilitate the reuse of knowledge related to the definition of business processes, as well as to provide an easier transition from models to executable processes by applying semantic technologies to BPM. In this article the authors focus on extending the scope of knowledge being reused from executable processes to semantic models' scope. This is done by providing some methodological extensions to existing BPM methodologies in order to take advantage of semantic technologies during business process modeling.

In distributed environment the changes and challenges faced by composite web services in their network environment are enormous. The primary issue in these systems is to distribute the load among various components of the composite web services to improve the performance through minimizing the response time. In this paper, we present a methodology to estimate the load sharing among composite web services using traditional workflow concept combined with game theory approach. In addition, we have developed a simulation model and observed that the results are promising for a better understanding of workload sharing among individual web services. We obtained the stable solution for ensuring the cooperation of the web services which further helps in capacity planning in composite web services network environment.

Web applications must deal with a rapidly evolving, distributed, heterogeneous environment of information and reasoning services. Many applications obtain information from multiple sources and thus need to determine how, why, and when to use answers. Currently few if any webbased reasoning services make explanations available and, if they do, the supporting proofs of these explanations are rarely portable across applications. Thus, proofs, if available, are difficult to understand and more difficult to combine. This ...

In this research was developed a language to describe a robot-based assembly. This language has an important role in the generation of robot programs. To accomplish with the objective of automatic generation of robot programs, it was developed a system, which consists on the next subsystems: a High-level-language Planner, a Generic-level-language Parser and a Wrapper-generic-level language.

Business process models mostly exist without a corresponding reference ontology of the business and its domain, or without semantic specifications of their basic tasks to be executed through software. This work shows our 'big picture' of integrated support for modeling business processes in BPMN 2.0 (Business Process Model and Notation). It illustrates representing semantic information of such business processes and its links. So, this paper presents our comprehensive integration of executable business process models represented in BPMN 2.0 with semantic concept and service task specifications. Our integration can be used for model verification and generation, as well as model execution with assigned (software) services (or objects).

Finding specification of pervasive systems is difficult because it requires making certain environmental assumptions explicit at design-time, and describing the software in a way that facilitates runtime composition. This paper describes how a systematic refinement of specifications from descriptions of the system's environment and requirements can be automated. Our notion of requirements allows individual features in the system to be inconsistent with each other. Resolution of conflicts at design-time is often over-restrictive ...

TRIPLE was designed as a practical rule language for data manipulation applications. Over the last couple of years the language has been deployed in various applications and use case studies. In this paper we first introduce the design principles of TRIPLE and then present some of the applications for which this language has been used.

In this paper we show how personalization techniques from the area of adaptive hypermedia can be achieved in the semantic web. Our approach is based on rule-based reasoning enabled by semantic web technologies. The personalization techniques are formalized as reasoning rules. The rules are able to reason over distributed information resources annotated with semantic web metadata formats. This leads towards the realization of an adaptive semantic web idea which provides personalized, adaptive access to information, services, or other, distributed resources.

Traditional adaptive hypermedia systems have focused on providing adaptation functionality on a closed corpus, while Web search interfaces have delivered non-personalized information to users. In this paper, we show how we integrate closed corpus adaptation and global context provision in a Personal Reader environment. The local context consists of individually optimized recommendations to learning materials within the given corpus; the global context provides individually optimized recommendations to resources found on the Web, e. g., FAQs, student exercises, simulations, etc. The adaptive local context of a learning resource is generated by applying methods from adaptive educational hypermedia in a semantic web setting. The adaptive global context is generated by constructing appropriate queries, enrich them based on available user profile information, and, if necessary, relax them during the querying process according to available metadata.

We present the SmartWeb Demonstrator for multimodal and mobile querying of semantic resources and the open WWW. The end-user interface consists of a Pocket Data Assistant which accepts written or spoken questions as input and delivers answers based on a multitude of resources including a semantic knowledge base, semantically annotated online web services, and semi-automatically created knowledge from text-based web pages. If answers cannot be found using these structured resources, then the system returns answers based on linguistic query-answering techniques on the open WWW.

E-tutoring system is a sophisticated, integrated software system that applies Artificial Intelligence (AI) concepts and methods to teaching and learning problems and requirements. They allow the student to search for level of knowledge and learning methods used to enhance or correct the students' knowledge. In a specified area of knowledge, they are intended to support and improve teaching and learning process while preserving the learner's uniqueness. E-tutoring system research has successfully delivered systems providing support for one-to-one tutoring. Most of these systems are actively used in real-world settings and have even contributed to changing traditional education. To improve the future research related to the enhancement of tutoring, we proposed an ontology domain model including besides the standard modules a common shared ontology database and knowledge-based background, too. The shared ontology databases can improve the quality of the domain models both in tutor and student models. In this paper, we give a survey on current E-tutoring systems, E-tutoring system technologies and proposed E-tutoring architecture. In this paper, we focus on domain module, our goal here is to let the e-tutor system prepare the material according to the students' capabilities. As a result, the proposed model can solve the problem of the current E-tutoring systems, can meet the features of reusability, standardization, open knowledge and flexibility, by using the ontology domain model we can avoid the problem of isolated database. The constructed ontology can be used in the future to control adaptive intelligent e-tutor frameworks.

In this paper, we introduce a new mathematical structure: fractal hypergraph. Due to the hierarchical and compositional nature of fractal hypergraphs, representations based on fractal hypergraphs can capture and abstract the object-oriented nature of SystemC. We propose a formal semantics of Sys-temC components based on fractal hypergraphs that has already be used in a formal debugger of SystemC components.

In this paper the Web Ontology Language (OWL) is examined to instantiate expert system knowledge bases intended for semantic Web applications. In particular, OWL is analyzed for expressing Unified Modeling Language (UML) representations that have been augmented with propositional logic asserted as inter-link constraints. The motivation is ultimately to provide declarative propositional logic constraints that can be represented in UML and declaratively implemented using OWL and other constructs to realize semantic Web knowledge base repositories and databases to facilitate expert system applications. The results of this paper show that OWL is sufficient for capturing most inter-link constraints asserted on generalization=specialization instances; however, OWL alone is inadequate for representing some inter-link constraints asserted on associations. We propose enhancements to OWL via RDF extensions for the reification of associations into classes. These extensions mitigate all concerns that were identified in OWL as part of this study. The result is increased support of declarative constraint representations, which can be expressed in knowledge bases in the context of the semantic Web.

It is a common characteristic of scientific applications to require the integration of information coming from multiple sources. This aspect usually confronts end-users with data management issues which involve the transportation of data from one system to another as well as the syntactic and semantic integration of data, i.e. data come in different formats and have different meanings. In order to deal with these issues in a systematic and well structured way, we propose a sophisticated framework based on process modeling. In this paper, we present the three major conceptual architectural abstractions of the system and detail its execution.

Crosscutting concerns in business processes have been addressed, among other forms, under the aspects orientation paradigm. The goal is reducing visualization complexity, allowing reuse and improving maintainability. Literature presents techniques that address aspects in BPM lifecycle stages of modeling and implementation. However, those techniques adopt different semantical representations, making the integration between those stages very difficult. This paper proposes a service identification method to select an implementation for aspects in order to meet goals set in the modeling stage. We describe an artifact produced with this purpose within an application scenario where Web Services are discovered and selected during a process execution. We conclude that aspects' behavior can be flexible and adaptable at runtime .

This paper deals with the organization of concepts and ideas as regards the relation between quality and web accessible services. We discuss the concept of service and service requestor. We investigate their mutual expectations and offered functionalities that involve both functional and non-functional requirements. The relation between nonfunctional requirements and quality attributes is presented by examining the related concepts of measurement and model. We contextualize the generic concept of service in the Web and Web services architecture and, finally, we briefly present current proposals for service functional and non-functional requirements description.

The main purpose of this study is to investigate the impact of short term assets and short term liabilities in cement industry of Pakistan for the period of last twelve years 2000-2011. Our intention was about the use of current assets and current liabilities how effecting the profitability of this sector. The data were collected from the financial analysis of the State Bank of Pakistan for non-financial company's analysis. The population of this study was the complete cement industry of the Pakistan. We have used multiple regressions through SPSS for the testing of this study hypothesis. The results show that cash is significant at 5% level of significance. Inventory and debtors are insignificant at 5% level of significance. The results also show that current liabilities and sales are highly significant at 5% level of significance. The current liabilities are negatively affecting the profitability. The variable sales are positively affecting the profitability. The current assets are also significant at 5% level of significance.

— With the development of Web Services, the retrieval of relevant services has become a challenge. The keyword-based discovery mechanism using UDDI and WSDL is insufficient due to the retrieval of a large amount of irrelevant information. Also, keywords are insufficient in expressing semantic concepts since a single concept can be referred using syntactically different terms. Hence, service capabilities need to be manually analyzed, which lead to the development of the Semantic Web for automatic service discovery and retrieval of relevant services and resources. This work proposes the incorporation of Semantic matching methodology in Semantic Web for improving the efficiency and accuracy of the discovery mechanism.

Abstract. Electronic Government initiatives, such as seamless public services delivered at one-stop government portals, require establishing collaborative networks among public-and private-sector organizations. However, semantic interoperability problems emerge as these organizations may differ in the terms and meanings they use to communicate, express their needs and describe resources they make available to each other. This paper describes typical semantic interoperability problems and presents a middleware solution to address ...

Research efforts have produced a lot of applications and hardware devices for healthcare services especially in the developed world. However, much still left to be desire in mobile wireless healthcare research that produces semantic web services applications solution especially for the developing African countries. The first successful implementation of a mobile wireless application for the healthcare industry in the United States of America (USA) was announced on 13 October, 2008 by InfoLogic. This paper presents our research in the design and implementation of a framework for cost cutting electronic healthcare delivery services for rural/suburban communities. This is achieved through the development of a semantic web services framework that would be deployed to provide wireless mobile healthcare delivery services and health management services for rural African communities. Currently no e-health application making use of semantic web services are known or reported in literature to have been implemented in any real life situation in Africa. The product of this research will be deployed in some selected rural communities in south-western Nigeria. Software artifacts will be implemented on the proposed framework. The software will be deployed for use by patients and healthcare practitioner in some selected hospitals in south-western Nigeria.

Bongard Problems (BPs) are a set of 100 visual puzzles set as a benchmark test for understanding the human concept learning abilities depending on contexts. It is still obscure how the human mind recognizes objects under minimal information, like amodal problems where only minimal information are available as sensory input. Though BPs have been well known among AI researchers as solutions towards understanding such human visual perception abilities, only a little progress has been made towards solving a set of BPs. In this study, a semantic web based meta-knowledge was developed along with a hierarchical logical inference to mimic human-logical inference ability in solving the Bongard problems. We applied this method to solve a set of fourteen BPs based on visual inputs from a perceiver (through an interface) and successfully demonstrated the system to find the unique distinction between the two classes in a given problem.

Web services have become popular in the modern infrastructure of the World Wide Web. They aim to provide automatic discovery, selection, and invocation of required applications (services) across the internet. However, the quality assurance aspects of web services remain a challenge. Recently, the semantic web has been introduced as an emerging technology which emphasizes presenting the meaning of the web content to achieve a machine processable automation. In this paper, we explore the synergy of applying specification based software testing techniques to semantic web services. Our approach investigates the possibility of deriving concrete test cases from the goal specification of a semantic web service in order to determine the correctness of a service implementation. Furthermore, we also propose coverage criteria to evaluate the generated test cases at both the goal and the service description levels. We demonstrate the generation and evaluation of the test cases from a goal specification with the help of a simplified discount example.

Human communication is highly fault tolerant: although words and phrases that are not jointly understood are often used, a shared common language can be used to explain these differences. In agent communication, however, mutual comprehension usually depends on a perfect matching of messages to internal ontologies. Thus any kind of ontological mismatch will lead to communication failure, even though large sec¬ tions of the ontologies may be common to both parties. Ontologies, once envisaged as definitive descriptions of what exists in a domain, are commonly not static but are continually updated and altered, both centrally and by individual users. As the envi¬ ronments in which agents interact become increasingly diverse and distributed, with agents being designed by a large number of different users, ontology mismatch be¬ comes increasingly common. Standard approaches to resolving this problem assume that the mismatched ontologies can be fully observed and often assume that it is desirable to match large sections, or even all, of the ontologies. However, this is not always a reasonable assumption, as many of these changes are not made public, and the computational cost of mapping entire ontologies is often prohibitive. We believe that it is more appropriate to assume that the ontologies of external agents are not available for observation, except for the specific parts of their ontologies revealed through normal agent communication. Con¬ sequently, a real-world solution, which we propose, is to patch specific instances of ontology mismatch when these particular mismatches lead to communication prob¬ lems. This thesis describes the development of ORS (Ontology Refinement System), a sys¬ tem designed to dynamically refine ontologies whenever mismatches lead to commu¬ nication problems during agent interaction. ORS contains a framework for agents to diagnose and refine ontological mismatch, integrated within an environment where iii planning agents can use this ability to achieve goals that would otherwise have been unreachable. These abilities are evaluated against genuine examples of ontological mismatch to demonstrate that they are useful and can be successfully performed.

Recognition is growing for the need of richer semantic specifications of Web Services to support automated service selection and invocation, automated or semi-automated service composition, as well as more comprehensive approaches to service monitoring. In this paper, we combine [12] an approach for composing Web Services on the semantic web and [10] using OWL-S for explicitly describing the semantics to Web Services. We propose an OWL-S based approach for the automatic composition of Semantic Web Services and present a technique to generate composite services from high-level declarative descriptions. We discuss its implementation for the shipment monitoring application, an open, multimodal end-to-end tracking and tracing system in the Border Control domain based on Semantic Web Services as part of the SAP Auto-ID infrastructure.

Service interface description languages such as WSDL, and related standards, are evolving rapidly to provide a foundation for interoperation between Web services. At the same time, Semantic Web service technologies, such as the Ontology Web Language for Services (OWL-S), are developing the means by which services can be given richer semantic specifications. Richer semantics can enable fuller, more flexible automation of service provision and use, and support the construction of more powerful tools and methodologies. Both sets of technologies can benefit from complementary uses and crossfertilization of ideas. This paper shows how to use OWL-S in conjunction with Web service standards, and explains and illustrates the value added by the semantics expressed in OWL-S.

Current industry standards for describing Web Services focus on ensuring interoperability across diverse platforms, but do not provide a good foundation for automating the use of Web Services. Representational techniques being developed for the Semantic Web can be used to augment these standards. The resulting Web Service specifications enable the development of software programs that can interpret descriptions

Ontology-based web service composition allows for integration of available web services in real-time to meet desired objectives. In order to evaluate the quality of composite web services at runtime, there is a pressing need to define a feasible real-time web service reliability model. In this paper, we present such a model. We first introduce a dynamic process model that supports the evaluation of web service reliability. Then we provide a hybrid reliability model for atomic web services by considering both software and hardware aspects of the services. In order to calculate efficiently the reliability of ontology-based dynamic composite web services, we present a recursive algorithm that evaluates the reliability of various service composition constructs in real-time. Finally, we use a case study to show how to compute and monitor the reliability of composite web services in real-time, and how our approach supports reliable ontology-based dynamic web service composition.