workflow partitioning in mobile information systems

The increasing success of wireless technologies is sustaining the diffusion of mobile information systems, but the youth of the underlying technology and its peculiar characteristics are impacting the development of such systems. For example, the execution of business processes in such a context must cope with the variable and fluctuating bandwidth available to the different devices. This leads the designer to stress the independence of each actor -- by minimizing interactions and knowledge sharing -- to increase the reliability of the whole system

A programming system for process coordination in virtual organisations

PhD thesisDistributed business applications are increasingly being constructed by composing them from services provided by various online businesses. Typically, this leads to trading partners coming together to form virtual organizations (VOs). Each member of a VO maintains their autonomy, except with respect to their agreed goals. The structure of the Virtual Organisation may contain one dominant organisation who dictates the method of achieving the goals or the members may be considered peers of equal importance. The goals of VOs can be defined by the shared global business processes they contain. To be able to execute these business processes, VOs require a flexible enactment model as there may be no single ‘owner’ of the business process and therefore no natural place to enact the business processes. One solution is centralised enactment using a trusted third party, but in some cases this may not be acceptable (for instance because of security reasons). This thesis will present a programming system that allows centralised as well as distributed enactment where each organisation enacts part of the business process. To achieve distributed enactment we must address the problem of specifying the business process in a manner that is amenable to distribution. The first contribution of this thesis is the presentation of the Task Model, a set of languages and notations for describing workflows that can be enacted in a centralised or decentralised manner. The business processes that we specify will coordinate the services that each organisation owns. The second contribution of this thesis is the presentation of a method of describing the observable behaviour of these services. The language we present, SSDL, provides a flexible and extensible way of describing the messaging behaviour of Web Services. We present a method for checking that a set of services described in SSDL are compatible with each other and also that a workflow interacts with a service in the desired manner. The final contribution of this thesis is the presentation of an abstract architecture and prototype implementation of a decentralised workflow engine. The prototype is able to enact workflows described in the Task Model notation in either a centralised or decentralised scenario

MPI-style Web services: An investigation into the potential of using Web services for MPI-style applications

This research investigates the potential of the Web services architecture to act as a platform for the execution of MPI-style applications. The work in this thesis is based upon extending current Web service methodologies and merging them with ideas from other research domains, such as high performance computing. MPIWS, an API to extend the functionality of standard Web services is introduced. MPIWS provides MPI-style message passing functionality to facilitate the execution of MPI-style applications using Web service based communication protocols. The thesis then presents a large selection of experiments that perform a comprehensive evaluation of MPIWS's performance. This performance is compared with an existing MPI implementation that has the option of transmitting data either via Java serialised objects, or via the Java native interface to an underlying C implementation of MPI. From the results obtained from these experiments, it can be concluded that using MPIWS for applications requiring MPI-style message passing between services is potentially a practical and efficient way of distributing coarse grained parallel applications. The results also show that the use of collective communication techniques within the Web services architecture can significantly improve the efficiency of suitable applications such as molecular dynamics simulation. MPI-style communication can also be used to enhance the performance of Web service based workflow execution. Tests conducted have evaluated a range of functionality that can be provided by the MPIWS tool. This evaluation shows that direct messaging between services, without sending data via the workflow manager, can improve the efficiency of Web service based workflow execution

Services State of Play - Compliance Testing and Interoperability Checking

The document contains an inventory of existing solutions for compliance testing and interoperability checking of services, the assumption being that the services are web services. Even if the emphasis is on geographical information and therefore on Geographical Information Systems, the document describes applicable solutions outside the geographical Information System domain.JRC.H.6-Spatial data infrastructure

Iterchanging Discrete Event Simulationprocess Interaction Modelsusing The Web Ontology Language - Owl

Discrete event simulation development requires significant investments in time and resources. Descriptions of discrete event simulation models are associated with world views, including the process interaction orientation. Historically, these models have been encoded using high-level programming languages or special purpose, typically vendor-specific, simulation languages. These approaches complicate simulation model reuse and interchange. The current document-centric World Wide Web is evolving into a Semantic Web that communicates information using ontologies. The Web Ontology Language OWL, was used to encode a Process Interaction Modeling Ontology for Discrete Event Simulations (PIMODES). The PIMODES ontology was developed using ontology engineering processes. Software was developed to demonstrate the feasibility of interchanging models from commercial simulation packages using PIMODES as an intermediate representation. The purpose of PIMODES is to provide a vendor-neutral open representation to support model interchange. Model interchange enables reuse and provides an opportunity to improve simulation quality, reduce development costs, and reduce development times

Service-Interoperabilität für naturwissenschaftliche Anwendungen : Identifikation und Anpassung von komponentenbasierten Service-Mediatoren

In der Softwareentwicklung wird die Serviceorientierung als neues Realisierungsparadigma propagiert. Sie erlaubt lose gekoppelte Services bedarfsbezogen in Workflows zu aggregieren. Hierbei ist die Überbrückung der Heterogenität dieser Services ein anerkanntes Problem von hohem wirtschaftlichem Interesse. Es besteht der Bedarf die Service-Interoperabilität weitestgehend automatisch herzustellen. In dieser Arbeit wurde ein Konzept für Service-Mediatoren entwickelt, die über eine offene und erweiterbare, software-unterstützte Prozedur (semi-)automatisch identifiziert und problembezogen in einen Workflow eingebettet werden können. Service-Mediatoren über\-brücken die Heterogenität der einzelnen Services und erzielen so die geforderte Service-Interoperabilität. Die offene Architektur und Entwicklung dieser Prozedur erlaubt erstmals die Vorteile gängiger Ansätze zu integrieren. Um einmal entwickelte Service-Mediatoren in verschiedenen Workflows einsetzen und wiederverwenden zu können, bedarf es ihrer gezielten Identifikation und Anpassung. Leider stellt gerade die Suche nach benötigten Service-Mediatoren ein besonders schwieriges Problem da. Dies gilt insbesondere, wenn erst mehrere geeignet verknüpfte Service-Mediatoren zusammen die Service-Interoperabilität erreichen und bereits bei der Suche diese Kombination identifiziert werden muss. Die Aspekte der Suche und der Anpassung erfordern eine Beschreibungssprache, die die Fähig\-keiten eines Service-Mediators sowohl syntaktisch als auch semantisch beschreiben kann. Mit der Mediator Profile Language (MPL) wurde eine derartige, auf OWL basierende Beschreibungssprache entwickelt, die die Grundlage des entworfenen Komponentenmodells der Service-Mediatoren bildet. Sie erlaubt u. a. die Beschreibung der Komposition mehrerer Service-Mediatoren, sowie deren Konfiguration über zustandsbehaftete Eigenschaftsfelder. Die semantische Annotation eines Service-Mediators geschieht hierbei über Konzepte einer Domänenontologie. Im Rahmen dieser Arbeit wurden Matchmaking-Algorithmen zur Suche entwickelt, die eine Identifikation adäquater Service-Mediatoren und deren Komposition erlauben. Durch den Einsatz von Ontologien zur semantischen Annotation der Service-Mediatoren kann die Suche auch über rein syntaktische Merkmale hinaus durchgeführt werden. Trotz der den Servicebeschreibungen innewohnenden Unschärfe wurde ein Verfahren realisiert, welches die Servicebeschreibungen auf MPL abbildet und dabei eine automatische Annotation durch die Konzepte einer Ontologie vornimmt. Die Matchmaking-Algorithmen wurden auch auf das Problem der semantischen Suche nach Service-Operationen übertragen. Die entwickelten ontologiebasierten Matchmaking-Verfahren liefern im Vergleich zu Standard-IR-Techniken signifikant bessere Ergebnisse, wie durch entsprechende Benchmarks mit anschließender Messung von Precision und Recall gezeigt werden konnte.Service Interoperability for Science Applications - Identification and Adaptation of Component-Based Service MediatorsService-orientation is a new software paradigm for building distributed, component-based software. It allows the aggregation of loosely coupled services into value-added workflows. In this context the gap between heterogeneous services is an accepted problem with particular commercial interest. Thus, there is the need to create service interoperability semi-automatically. In this thesis the concept of service mediators is developed. Through a software-aided procedure service mediators are identified, adapted and integrated into workflows in order to bridge the heterogeneity of different services. Service mediators are software components realizing for instance transformation facilities. The open architecture of the developed procedure allows the integration of benefits from current approaches. The discovery of relevant service mediators is a difficult problem, especially if several service mediators have to be combined adequately to reach the desired service interoperability. One major challenge is that such compositions have to be identified during discovery. The discovery and adaptation phases of the software-aided procedure require a suitable description of the capabilities of service mediators. Such a description should contain both syntactical and semantical information. The OWL-based Mediator Profile Language (MPL) addresses these issues. MPL permits among other things the description of compositions of service mediators as well as their customization by stateful properties. Semantical information is assigned by concepts of a domain ontology. In this dissertation different matchmaking algorithms were developed supporting the user in identifying relevant service mediators as well as new compositions of service mediators. Requirements for service mediators are derived from service descriptions and represented by query profiles in MPL. Even though the service descriptions are fuzzy the query generation algorithm automatically creates semantical annotations by mapping syntactical information to concepts of the domain ontology. These annotations are also stored within the query profile. Due to the application of the domain ontology the discovery process enables not only syntactical matchmaking but also semantical matchmaking. Furthermore, the matchmaking algorithms were transferred to the problem of discovering service operations. By measuring precision and recall it could be shown that ontology-based matchmaking is advantageously over standard information retrieval techniques

Patterns-based Evaluation of Open Source BPM Systems: The Cases of jBPM, OpenWFE, and Enhydra Shark

In keeping with the proliferation of free software development initiatives and the increased interest in the business process management domain, many open source workflow and business process management systems have appeared during the last few years and are now under active development. This upsurge gives rise to two important questions: what are the capabilities of these systems? and how do they compare to each other and to their closed source counterparts? i.e. in other words what is the state-of-the-art in the area?. To gain an insight into the area, we have conducted an in-depth analysis of three of the major open source workflow management systems - jBPM, OpenWFE and Enhydra Shark, the results of which are reported here. This analysis is based on the workflow patterns framework and provides a continuation of the series of evaluations performed using the same framework on closed source systems, business process modeling languages and web-service composition standards. The results from evaluations of the three open source systems are compared with each other and also with the results from evaluations of three representative closed source systems - Staffware, WebSphere MQ and Oracle BPEL PM, documented in earlier works. The overall conclusion is that open source systems are targeted more toward developers rather than business analysts. They generally provide less support for the patterns than closed source systems, particularly with respect to the resource perspective which describes the various ways in which work is distributed amongst business users and managed through to completion