Roy Grønmo

Model-driven Web services development

Web service technologies are becoming increasingly important for integrating systems and services. There is much activity and interest around standardization and usage of Web service technologies. The unified modeling language (UML) and the model driven architecture (MDA)/spl trade/ provide a framework that can be applied to Web service development. We describe a model-driven Web service development process, where Web service descriptions are imported into UML models; integrated into composite Web services; and the new Web service descriptions are exported. The main contributions are conversion rules between UML and Web services described by Web service description language (WSDL) documents and XML schema.

Transformations between UML and OWL-S

As the number of available Web services increases there is a growing demand to realize complex business processes by combining and reusing available Web services. The reuse and combination of services results in a composition of Web services that may also involve services provided in the Internet. With semantically described Web services, an automated matchmaking of capabilities can help identify suitable services. To address the need for semantically defined Web services, OWL-S and WSML have been proposed as competing semantic Web service languages. Both proposals are quite low-level and hard to use even for experienced Web service developers. We propose a UML profile for semantic Web services that enables the use of high-level graphical models as an integration platform for semantic Web services. The UML profile provides flexibility as it supports multiple semantic Web service languages. Transformations of both ways between OWL-S and UML are implemented to show that the UML profile is expressive enough to support one of the leading semantic Web service languages.

Toward standardised model to text transformations

The objective of this work is to assess the qualities of the MOFScript language, which has recently been submitted to the OMG as a proposed model to text transformation language. This is done by identifying requirements for this type of language and evaluating the MOFScript language with regard to these. The language is presented along with a tool implementation and compared with the alternative languages submitted to the OMG Model to Text RFP.

Developing scientific workflows from heterogeneous services

Scientific WorkFlows (SWFs) need to utilize components and applications in order to satisfy the requirements of specific workflow tasks. Technology trends in software development signify a move from component-based to service-oriented approach, therefore SWF will inevitably need appropriate tools to discover and integrate heterogeneous services. In this paper we present the SODIUM platform consisting of a set of languages and tools as well as related middleware, for the development and execution of scientific workflows composed of heterogeneous services.

Model-Driven Web Service Development

Web service technologies are becoming increasingly important for integrating systems and services. There is much activity and interest around standardization and usage of Web service technologies. Contemporary Web services are described in the Web Service Description Language (WSDL). However, WSDL documents can be difficult to understand for service developers. This article recommends a model-driven process for Web service development combining the graphical modeling language UML with WSDL. The Unified Modeling Language (UML) is developed by Object Management Group. In the proposed process, Web service descriptions (in WDSL) are converted to UML; their UML models are integrated to form composite Web services; and then the new Web service descriptions are exported. The main contribution of this article is a “pure UML†modeling strategy supported by implementation of two-way conversion rules between the UML models and the WSDL documents.

Improving reuse of web service compositions

We describe a methodology for assembling composite services based on three basic processes which are independent of the concrete implementation: Service Abstraction Process, Service Composition Process, and Translation Process. These processes share the concept of integrated component composed of two key aspects: a specific set of the Aalsts workflow patterns together with a component-style composition of complex services. We propose a novel approach that implements the steps of such methodology, providing an efficient manner for developing service compositions and enhancing the expressiveness of target composition languages like BPEL4WS. Here we focus on the description of the Service Abstraction Process, a critical step in order to enhance the service composition by facilitating the reuse of existing services.

Can Graph Transformation Make Aspect Languages for BPEL Redundant

The aspect language AO4BPEL has been introduced as a way to modularize cross-cutting concerns in Web service compositions that are specified in BPEL. AO4BPEL can be difficult to understand and to write for non-XML experts. This paper explores if algebraic graph transformation rules can be used to specify BPEL aspects at the modeling level, and make new aspect languages like AO4BPEL redundant. Three AO4BPEL examples, taken from the literature, are used to test the suitability of graph transformation as a means to simulate BPEL aspects.

Supporting GI standards with a model-driven architecture

This paper describes an approach to generate GI standards such as OpenGIS Geography Markup Language (GML) and ISO 19118 XML Encoding from UML. GML application schemas in OpenGIS context are being developed by using XML Schema directly and without any relation to UML models. It is SINTEFs belief that a model-driven architecture using UML is more sutiable for specifying GML application schemas. SINTEF has used a model-driven architecture for several years and has also been strongly involved in defining the ISO GI standards. The model-driven architecture is investigated further by SINTEF in the project GeNorway-Model-based infrastructure for living geospatial data in eNorway. GeNorway shall implement a Norwegian version of an OGC-conform Web Mapping test case built on top of the Norwegian Spatial Data Infrastructure (NGIS).

A service composition construct to support iterative development

Development of composed services requires a continues adaptation of the composed service to the changing environment of offered services. Services may no longer be available or may change performance characteristics, price, or quality of service criteria after they have been selected and used in a composition. The replacement of such a service requires a good understanding why this service got selected in the first place. This is hard to accomplish as it is known from software maintenance. Therefore we propose an approach where the conceptual task implemented by a selected service as well as the relationship between task and selected service is explicated and maintained during the complete life cycle of a composed service. This covers the design of the composition, derivation of service search criteria, and the execution of the composed service. The approach has been validated by an implementation in the Service Composition Studio (SERCS) supporting the iterative development of composed services.