Aspect] is a simple and practical aspect-oriented extension to Java With just a few new constructs, AspectJ provides support for modular implementation of a range of crosscutting concerns. In AspectJ's dynamic join point model, join points are well-defined points in the execution of the program; pointcuts are collections of join points; advice are special method-like constructs that can be attached to pointcuts; and aspects are modular units of crosscutting implementation, comprising pointcuts, advice, and ordinary Java member declarations. AspectJ code is compiled into standard Java bytecode. Simple extensions to existing Java development environments make it possible to browse the crosscutting structure of aspects in the same kind of way as one browses the inheritance structure of classes. Several examples show that AspectJ is powerful, and that programs written using it are easy to understand.

An overview of AspectJ

The article reviews the book “Information Rules: A Strategic Guide to the Network Economy,” by Carl Shapiro and Hal R. Varian.

Information Rules: A Strategic Guide to the Network Economy

Biogas from Waste and Renewable Resources , Biogas from Waste and Renewable Resources , کتابخانه الکترونیک و دیجیتال - آذرسا

http://www.beck-shop.de/fachbuch/inhaltsverzeichnis/9783527327980_TOC_001.pdf

Biogas from Waste and Renewable Resources

Concrete mathematics, a foundation for computer science, by Ronald L. Graham, Donald E. Knuth and Oren Patashnik. Pp 625. £24·95. 1989. ISBN 0-201-14236-8 (Addison-Wesley)

Composition of Web services has received much interest to support business-to-business or enterprise application integration. On the one side, the business world has developed a number of XML-based standards to formalize the specification of Web services, their flow composition and execution. This approach is primarily syntactical: Web service interfaces are like remote procedure call and the interaction protocols are manually written. On the other side, the Semantic Web community focuses on reasoning about web resources by explicitly declaring their preconditions and effects with terms precisely defined in ontologies. For the composition of Web services, they draw on the goal-oriented inferencing from planning. So far, both approaches have been developed rather independently from each other. We compare these approaches and discuss their solutions to the problems of modeling, composing, executing, and verifying Web services. We discuss what makes the Web service composition so special and derive challenges for the AI planning community.

Web Service Composition - Current Solutions and Open Problems

The Semantic Web will allow software agents to understand and reason about data provided by Web applications. Unfortunately, formal ontologies, needed to express data semantics, are often not readily available. However, common data schemas can help to create ontologies. We propose mappings from XML Schema to OWL as well as XML to RDF and show how web engineering can benefit from the gained expressiveness as well as the use of inference services.

/pdf/lifting-xml-schema-to-owl-265ijgawhw.pdf

Lifting XML Schema to OWL

For the majority of front-end e-business systems, the assumption of a coherent and homogeneous set of interfaces is highly unrealistic. Problems start in the back-end, with systems characterised by heterogeneous mix of applications and business processes. Integration can be complex and expensive, as systems evolve more in accordance with business needs then with technical architectures. E-business systems are faced with the challenge to give a coherent image of a diversified reality. Web Services make business interfaces more efficient, but effectiveness is a business requirement of at least comparable importance.In this paper, we propose a technique for automatic reconciliation of the Web Service interfaces involved in inter-organisational business processes. The working assumption is that the Web Service front-end of each company, is represented by a set of WSDL and WSCL interfaces. The result of our reconciliation method is a common interface that all the parties can effectively enforce. Indications are also given on ways to adapt individual interfaces to the common one. The technique was embodied in a prototype that we also present.

Web service interfaces for inter-organisational business processes an infrastructure for automated reconciliation

Service-oriented computing is meant to support loose relationships between organisations: Collaboration procedures on the application-level translate to interaction processes via Web Services. Service composition deals with the specification and enforcent of such processes. Its main focus is on service orchestration where workflow managent is utilised for proactive coordination. In such an approach, coordination process and interaction logic are usually captured in the same workflow - which leads to deficiencies in recognising the possible impact of operational coordination on the interaction logic. In this paper, we claim that the choice of coordination alternatives impacts the quality of the composed service and has to be customised to each specific service case. As a consequence, we outline a solution that is based on service interaction patterns where the paradigms of patterns and idioms are applied to interaction procedures and orchestration processes. This allows studying a) reusable interaction patterns typical for service relationships and b) for each pattern a range of possible coordination idioms. Finally, we sketch a technique that refines the service logic based on analysis of its interaction patterns and utilisation of suitable coordination idioms selected by rules in terms of changing service context.

/pdf/flexible-coordination-of-service-interaction-patterns-1nl5pb3w8d.pdf

Flexible coordination of service interaction patterns

Over the last two years, portal sites surfaced as a major trend in electronic commerce. Unlike many other exaggerated trends, portals have become an important facet of the World Wide Web which is likely to stay. Emerging from search engines and catalogues, they integrate an increasing amount of information and functionality. The paper reflects on portal characteristics as well as on foundations of their realization and introduces technology needed for the next generation service trading concepts: based on the promising open source project Jetspeed, a prototype of the GIBRALTAR service portal is introduced, capable of integrating, trading and composing complex remote e-services.

Advanced concepts for next generation portals

For the majority of front-end e-business systems, the assumption of a coherent and homogeneous set of interfaces is highly unrealistic. Problems start in the back-end, with systems characterised by a heterogeneous mix of applications and business processes. Integration can be complex and expensive, as systems evolve more in accordance with business needs than with technical architectures. E-business systems are faced with the challenge to give a coherent image of a diversified reality. Web services make business interfaces more efficient, but effectiveness is a business requirement of at least comparable importance. We propose a technique for automatic reconciliation of the Web service interfaces involved in inter-organisational business processes. The working assumption is that the Web service front-end of each company is represented by a set of WSDL and WSCL interfaces. The result of our reconciliation method is a common interface that all the parties can effectively enforce. Indications are also given on ways to adapt individual interfaces to the common one. The technique was embodied in a prototype that we also present.

/pdf/web-service-interfaces-for-inter-organisational-business-3caf3ckejl.pdf

Christian Zirpins

Papers

Lifting XML Schema to OWL

Web service interfaces for inter-organisational business processes an infrastructure for automated reconciliation

Flexible coordination of service interaction patterns

Advanced concepts for next generation portals

Web service interfaces for inter-organisational business processes an infrastructure for automated reconciliation