Showing papers on "Services computing published in 2004"

QoS-aware middleware for Web services composition

Abstract: The paradigmatic shift from a Web of manual interactions to a Web of programmatic interactions driven by Web services is creating unprecedented opportunities for the formation of online business-to-business (B2B) collaborations. In particular, the creation of value-added services by composition of existing ones is gaining a significant momentum. Since many available Web services provide overlapping or identical functionality, albeit with different quality of service (QoS), a choice needs to be made to determine which services are to participate in a given composite service. This paper presents a middleware platform which addresses the issue of selecting Web services for the purpose of their composition in a way that maximizes user satisfaction expressed as utility functions over QoS attributes, while satisfying the constraints set by the user and by the structure of the composite service. Two selection approaches are described and compared: one based on local (task-level) selection of services and the other based on global allocation of tasks to services using integer programming.

Whither Services Marketing? In Search of a New Paradigm and Fresh Perspectives

Abstract: This article examines the received wisdom of services marketing and challenges the validity and continued usefulness of its core paradigm, namely, the assertion that four specific characteristics—i...

Service-Oriented Architecture: A Field Guide to Integrating XML and Web Services

Abstract: Web services is the integration technology preferred by organizations implementing service-oriented architectures. I would recommend that anybody involved in application development obtain a working knowledge of these technologies, and I'm pleased to recommend Erl's book as a great place to begin.-Tom Glover, Senior Program Manager, Web Services Standards, IBM Software Group, and Chairman of the Web Services Interoperability Organization (WS-I).An excellent guide to building and integrating XML and Web services, providing pragmatic recommendations for applying these technologies effectively. The author tackles numerous integration challenges, identifying common mistakes and providing guidance needed to get it right the first time. A valuable resource for understanding and realizing the benefits of service-oriented architecture in the enterprise.-David Keogh, Program Manager, Visual Studio Enterprise Tools, Microsoft.Leading-edge IT organizations are currently exploring second generation web service technologies, but introductory material beyond technical specifications is sparse. Erl explains many of these emerging technologies in simple terms, elucidating the difficult concepts with appropriate examples, and demonstrates how they contribute to service-oriented architectures. I highly recommend this book to enterprise architects for their shelves.-Kevin P. Davis, Ph. D., Software Architect.Service-oriented integration with less cost and less riski? i? The emergence of key second-generation Web services standards has positioned service-oriented architecture (SOA) as the foremost platform for contemporary business automation solutions. The integration of SOA principles and technology is empowering organizations to build applications with unprecedented levels of flexibility, agility, and sophistication (while also allowing them to leverage existing legacy environments).This guide will help you dramatically reduce the risk, complexity, and cost of integrating the many new concepts and technologies introduced by the SOA platform. It brings together the first comprehensive collection of field-proven strategies, guidelines, and best practices for making the transition toward the service-oriented enterprise.Writing for architects, analysts, managers, and developers, Thomas Erl offers expert advice for making strategic decisions about both immediate and long-term integration issues. Erl addresses a broad spectrum of integration challenges, covering technical and design issues, as well as strategic planning. Covers crucial second-generation (WS-*) Web services standards: BPEL4WS, WS-Security, WS-Coordination, WS-Transaction, WS-Policy, WS-ReliableMessaging, and WS-Attachments Includes hundreds of individual integration strategies and more than 60 best practices for both XML and Web services technologies Includes a complete tutorial on service-oriented design principles for business and technical modeling Explores design issues related to a wide variety of service-oriented integration architectures that integrate XML and Web services into legacy and EAI environments Provides a clear roadmap for planning a long-term migration toward a standardized service-oriented enterpriseService-oriented architecture is no longer an exclusive discipline practiced only by expensive consultants. With this book's help, you can plan, architect, and implement your own service-oriented environments-efficiently and cost-effectively.About the Web SitesErl's Service-Oriented Architecture books are supported by two Web sites. http://www.soabooks.com provides a variety of content resources and http://www.soaspecs.com supplies a descriptive portal to referenced specifications.

Understanding and Managing the Services Supply Chain

Abstract: SUMMARY Services have become increasingly important as the driving force in the U.S. economy. However, there has been little research to date on services supply chains. It is believed that service businesses can benefit by applying some best practices from manufacturing to their processes. However, the inherent differences in services create a need for supply chain management tools specific to the services sector. This article documents the growing importance of the services sector and of services purchasing. Next, it develops a supply chain framework appropriate for a services supply chain by comparing and contrasting the applicability of three product-based manufacturing models: Global Supply Chain Forum Framework, SCOR and Hewlett-Packard's Supply Chain Management Model. Finally, this research describes the challenges for procurement professionals managing purchases for a services supply chain and provides suggestions for use of supply chain management theory, and practices for improvement.

The utility business model and the future of computing services

Abstract: The utility business model is shaped by a number of characteristics that are typical in public services: users consider the service a necessity, high reliability of service is critical, the ability to fully utilize capacity is limited, and services are scalable and benefit from economies of scale. This paper examines the utility business model and its future role in the provision of computing services.

The Open Grid Services Architecture

Abstract: Publisher Summary This chapter describes the Open Grid Services Architecture (OGSA)—the standards-based Grid computing framework. It introduces the service-oriented architecture principles that underlie OGSA and provides a detailed description of the Web services mechanisms and the Open Grid Services Infrastructure specification that together define the core interfaces and behaviors underlying OGSA. The development of OGSA represents a natural evolution of the Globus Toolkit 2.0 in which the key concepts of factory, registry, reliable and secure invocation, and so on exist in a less general and flexible form and without the benefits of a uniform interface definition language. The development of OGSA also represents a natural evolution of Web services. By integrating support for transient, stateful service instances with existing Web services technologies, OGSA extends significantly the power of the Web services framework, while requiring only minor extensions to existing technologies. A defining feature of Grids is the sharing of networks, computers, and other resources and services. This sharing introduces a need for resource and service management.

Aspect-oriented web service composition with AO4BPEL

Abstract: Web services have become a universal technology for integration of distributed and heterogeneous applications over the Internet. Many recent proposals such as the Business Process Modeling Language (BPML) and the Business Process Execution Language for Web Services (BPEL4WS) focus on combining existing web services into more sophisticated web services. However, these standards exhibit some limitations regarding modularity and flexibility. In this paper, we advocate an aspect-oriented approach to web service composition and present AO4BPEL, an aspect-oriented extension to BPEL4WS. With aspects, we capture web service composition in a modular way and the composition becomes more open for dynamic change.

Planning and Monitoring Web Service Composition

Abstract: The ability to automatically compose web services, and to monitor their execution, is an essential step to substantially decrease time and costs in the development, integration, and maintenance of complex services. In this paper, we exploit techniques based on the “Planning as Model Checking” approach to automatically compose web services and synthesize monitoring components. By relying on such a flexible technology, we are able to deal with the difficulties stemming from the unpredictability of external partner services, the opaqueness of their internal status, and the presence of complex behavioral requirements. We test our approach on a simple, yet realistic example; the results provide a witness to the potentiality of this approach.

Smart monitors for composed services

Abstract: Service-based approaches are widely used to integrate heterogenous systems. Web services allow for the definition of highly dynamic systems where components (services) can be discovered and QoS parameters negotiated at run-time. This justifies the need for monitoring service compositions at run-time. Research on this issue, however, is still in its infancy.We investigate how to monitor dynamic service compositions with respect to contracts expressed via assertions on services. Dynamic compositions are represented as BPEL processes which can be monitored at run-time to check whether individual services comply with their contracts. Monitors can be automatically defined as additional services and linked to the service composition.We present two alternative implementations of our monitoring approach: one based on late-binding and reflection and the other based on a standard assertion system. The two implementations are exemplified on a case study.

Quality of Service for Web Services

Abstract: The World Wide Web is evolving from being a pure information repository to a more functional and service oriented platform thanks to technologies such as Web Services. This technology offers a homogeneous representation of Web elements and the ways they are communicating that make it possible to deal with the inherent structural and behavioural heterogeneities of the Web. A Web service can be seen as an autonomous functional element that is loosely coupled to other Web services and can be discovered and deployed in Web-based applications. Autonomity and loose coupling make Web services a viable light weight complementary componentbased approach for design and development of dynamic distributed systems for more heavy weight solutions such as OMG’s CORBA and Microsoft’ s DCOM. In this paper, we take the position that if Web Services are going to be considered as reusable commercial of-the-shelf (COTS) components, their Quality of Service (QoS) needs to be expressed explicitly and measured independently. More specifically, we present and discuss possible quality aspects that need to be represented and quantified for Web Services.

Authorization and privacy for semantic Web services

Abstract: Web services will soon handle users' private information. They'll need to provide privacy guarantees to prevent this delicate information from ending up in the wrong hands. More generally, Web services will need to reason about their users' policies that specify who can access private information and under what conditions. These requirements are even more stringent for semantic Web services that exploit the semantic Web to automate their discovery and interaction because they must autonomously decide what information to exchange and how. In our previous work, we proposed ontologies for modeling the high-level security requirements and capabilities of Web services and clients.1 This modeling helps to match a client's request with appropriate services-those based on security criteria as well as functional descriptions.

Filtering and selecting semantic Web services with interactive composition techniques

Abstract: To demonstrate the utility of semantic Web service descriptions for service composition, we've developed a goal-oriented, interactive composition approach that uses matchmaking algorithms to help users filter and select services while building the composition. filtering and selecting services helps the user drive the composition process. We've implemented composition. Indeed, it is the filtering and selection of services that helps the user drive these ideas in a prototype system that can compose the Web services deployed on the Internet and provide filtering capabilities where a large number of similar services might be available.

Value Webs: using ontologies to bundle real-world services

Abstract: Real-world services - that is, nonsoftware-based services - differ significantly from Web services, usually defined as software functionality accessible and configurable over the Web. Because of the economic, social, and business importance of the service concept in general, we believe it's necessary to rethink what this concept means in an ontological and computational sense. We deal about the OBELIX (ontology-based electronic integration of complex products and value chains) project has therefore developed a generic component-based ontology for real-world services. This OBELIX service ontology is first of all a formalization of concepts that represent the consensus in the business science literature on service management and marketing. We express our service ontology in a graphical, network-style representation, and we've developed support tools that facilitate end-user modeling of services. Then, automated knowledge-based configuration methods let business designers and analysts analyze service bundles. We've tested our ontology, methods, and tools on applications in real-world case studies of different industry sectors.

Generating test cases for web services using data perturbation

Abstract: Web services have the potential to dramatically reduce the complexities and costs of software integration projects. The most obvious and perhaps most significant difference between Web services and traditional applications is that Web services use a common communication infrastructure, XML and SOAP, to communicate through the Internet. The method of communication introduces complexities to the problems of verifying and validating Web services that do not exist in traditional software. This paper presents a new approach to testing Web services based on data perturbation. Existing XML messages are modified based on rules defined on the message grammars, and then used as tests. Data perturbation uses two methods to test Web services: data value perturbation and interaction perturbation. Data value perturbation modifies values according to the data type. Interaction perturbation classifies the communication messages into two categories: RPC communication and data communication. At present, this method is restricted to peer-to-peer interactions. The paper presents preliminary empirical evidence of its usefulness.

Approaches to semantic web services: An overview and comparisons

Abstract: The next Web generation promises to deliver Semantic Web Services (SWS); services that are self-described and amenable to automated discovery, composition and invocation. A prerequisite to this, however, is the emergence and evolution of the Semantic Web, which provides the infrastructure for the semantic interoperability of Web Services. Web Services will be augmented with rich formal descriptions of their capabilities, such that they can be utilized by applications or other services without human assistance or highly con-strained agreements on interfaces or protocols. Thus, Semantic Web Services have the potential to change the way knowledge and business services are consumed and provided on the Web. In this paper, we survey the state of the art of current enabling technologies for Semantic Web Services. In addition, we characterize the infrastructure of Semantic Web Services along three orthogonal dimensions: activities, architecture and service ontology. Further, we examine and contrast three current approaches to SWS according to the proposed dimensions.

Towards context-aware adaptable web services

Abstract: In this paper, we present a context framework that facilitates the development and deployment of context-aware adaptable Web services. Web services are provided with context information about clients that may be utilized to provide a personalized behavior. Context is extensible with new types of information at any time without any changes to the underlying infrastructure. Context processing is done by Web services, context plugins, or context services. Context plugins and context services pre- and post-process Web service messages based on the available contextinformation. Both are essential for automatic context processing and automatic adaption of Web services to new context types without the necessity to adjust the Web services themselves. We implemented the context framework within the ServiceGlobe system, our open and distributed Web service platform.

Engineering Web service - agent integration

Abstract: Web services are fast emerging as the dominant means for connecting remotely executing programs via well established Internet protocols and commonly used machine readable representations. Software agents are now increasingly used in commercial applications to solve complex engineering problems, and these applications often expose or make use of Web services. As such, this paper presents a gateway architecture for connecting software agents and Web services in a transparent manner with fully automatic operation. This gateway allows Web services to invoke agent services and vice versa by translating message encodings and service descriptions between the two technologies. We also address how software agents offer the opportunity to introduce new modalities in the ways Web services are used and manipulated, including redirection, aggregation, integration and administration.

Efficient Selection and Monitoring of QoS-Aware Web Services with the WS-QoS Framework

Abstract: While the concept of UDDI supports the automatic discovery of services implementing a common public tModel interface, there have been only few attempts to find a standardized form to describe the quality of service (QoS) properties of Web services. We introduce our approach "Web service QoS (WS-QoS)" that enables an efficient, dynamic, and QoS-aware selection and monitoring of Web services. The prototype of our approach is implemented with the .NET technology, including the following components: a WS-QoS Editor for the specification of QoS properties, a WS-QoS Requirement Manager for retrieving QoS requirements specified by client applications, a Web service broker for an efficient and QoS-aware selection of Web service offers, and a WS-QoS Monitor for checking the compliance of the service offers.

A conceptual architecture for semantic web services

Abstract: In this paper, we present an abstract conceptual architecture for semantic web services. We define requirements on the architecture by analyzing a set of case studies developed as part of the EU Semantic Web-enabled Web Services project. The architecture is developed as a refinement and extension of the W3C Web Services Architecture. We assess our architecture against the requirements, and provide an analysis of OWL-S.

Interoperability among independently evolving web services

Abstract: The increasing popularity of XML Web services motivates us to examine if it is feasible to substitute one vendor service for another when using a Web-based application, assuming that these services are "derived from" a common base. If such substitution were possible, end users could use the same application with a variety of back-end vendor services, and the vendors themselves could compete on price, quality, availability, etc. Interoperability with substituted services is non-trivial, however, and four types of incompatibilities may arise during such interoperation -- structural, value, encoding and semantic. We address these incompatibilities three-fold: (1) static and dynamic analysis tools to infer whether an application is compatible with a substituted service, (2) semi-automatically generated middleware components called cross-stubs that actually resolve incompatibilities and enable interoperation with substituted services, and (3) a lightweight mechanism called multi-option types to enable applications to be written from the ground up in an interoperation-friendly manner. Using real applications and services as examples, we both demonstrate and evaluate our tools and techniques for enabling interoperation with substituted services.

Service components for managing the life-cycle of service compositions

Abstract: Web services are becoming the prominent paradigm for distributed computing and electronic business. This has raised the opportunity for service providers and application developers to develop value-added services by combining existing web services. However, current web service composition solutions do not address software engineering principles for raising the level of abstraction in web-services by providing facilities for packaging, re-using, specializing and customizing service compositions.In this paper we propose the concept of service component that packages together complex services and presents their interfaces and operations in a consistent and uniform manner in the form of an abstract class definition, Service components are internally synthesized out of reused, specialized, or extended complex web services and just like normal web services are published and can thus be invoked by any service-based application. In addition, we present an integrated framework and prototype system that manage the entire life-cycle of service components ranging from abstract service component definition, scheduling, and construction to execution.

Service framework with local proxy for representing remote services

Abstract: In an information appliance system 100, a user device 108 comprises a client platform (200, FIG. 5) that includes a service framework (235, FIG. 5) to discover and connect with a variety of services, both remote and local, transient and persistent, and to disconnect from them when they are no longer of interest or become unavailable. The service framework 235 provides a standard, consistent, simplified way for services to make themselves available and for service-using entities to locate and connect with the services of interest to them. From the perspective of the client platform 200, all services, whether local or remote, are presented as local services to the application. Each remote service is represented as a local service through the use of a local proxy that insulates the service user from the complexities of communicating with a remote server. Various methods of operating a service framework are also described.

Dynamic data integration using Web services

Abstract: We address the problem of large-scale data integration, where the data sources are unknown at design time, are from autonomous organisations, and may evolve. Experiments are described involving a demonstrator system in the field of health services data integration within the UK. Current Web services technology has been used extensively and largely successfully in these distributed prototype systems. The work shows that Web services provide a good infrastructure layer, but integration demands a higher level "broker" architectural layer; the paper identifies eight specific requirements for such an architecture that have emerged from the experiments, derived from an analysis of shortcomings which are collectively due to the static nature of the initial prototype. The way in which these are being met in the current version in order to achieve a more dynamic integration is described.

Triple-Space Computing: Semantic Web Services Based on Persistent Publication of Information

Abstract: This paper discusses possible routes to moving the web from a collection of human readable pieces of information connecting humans, to a webthat connects computing devices based on machine-processable semantics of dataand distributed computing. The current shortcomings of web service technologyare analyzed and a new paradigm for fully enabled semantic web services isproposed which is called triple-based or triple-space computing.

XML-based specification for Web services document security

Abstract: The Internet and related technologies have seen tremendous growth in distributed applications such as medicine, education, e-commerce, and digital libraries. As demand increases for online content and integrated, automated services, various applications employ Web services technology for document exchange among data repositories. Web services provide a mechanism to expose data and functionality using standard protocols, and hence to integrate many features that enhance Web applications. XML, a well-established text format, is playing an increasingly important role in supporting Web services. XML separates data from style and format definition and allows uniform representation, interchange, sharing, and dissemination of information content over the Internet. XML and Web services provide a simplified application integration framework that drives demand for models that support secure information interchange. Providing document security in XML-based Web services requires access control models that offer specific capabilities. Our XML-based access control specification language addresses a new set of challenges that traditional security models do not address.

The export of e‐services in the age of technology transformation: challenges and implications for international service providers

Abstract: Advancements in information and communication technologies have created unprecedented opportunities to services providers in both developing and developed countries. The service sector represents one of the fastest growing areas of exports in the global trade. The Internet and e‐commerce make it possible to sell a variety of services, ranging from airline tickets to financial services, from anywhere in the world, around the clock. International delivery of services through electronic means is creating value in the supply chain by the reduction of many of the barriers to entry. This paper focuses on the determinants influencing the diffusion and export of e‐services across borders. The paper also presents strategic challenges, followed by implications for service providers.

Adding high availability and autonomic behavior to Web services

Abstract: Rapid acceptance of the Web Services architecture promises to make it the most widely supported and popular object-oriented architecture to date One consequence is that a wave of mission-critical Web Services applications will certainly be deployed in coming years Yet the reliability options available within Web Services are limited in important ways To use a term proposed by IBM, Web Services systems need to become far more autonomic, configuring themselves, diagnosing faults, and managing themselves High availability applications need more attention Moreover, the scenarios in which such issues arise often entail very large deployments, raising questions of scalability In this paper we propose a path by which the architecture could be extended in these respects