Towards an aspect weaving BPEL engine

This position paper proposes the use of dynamic aspects and the visitor design pattern to obtain a highly configurable and extensible BPEL engine. Using these two techniques, the core of this infrastructural software can be customised to meet new requirements and add features such as debugging, execution monitoring, or changing to another Web Service selection policy. Additionally, it can easily be extended to cope with customer-specific BPEL extensions. We propose the use of dynamic aspects not only on the engine itself but also on the workflow in order to tackle the problems of Web Service hot deployment and hot fixes to long running processes. In this way, composing aWeb Service "on-the-fly" means weaving its choreography interface into the workflow

INTEROP deliverable DTG 6.2 : Method repository

This deliverable presents the INTEROP method chunks repository (MCR), its architecture and provided services. It includes the definition of a reusable method chunk, its structure, illustrated with examples of method chunks stored in the repository and guidelines for method chunks definition and characterisation covering tasks TG6.2 and TG6.3 of the work plan of the task group. The main result is the definition of the structure of the method chunk repository emphasizing the link to interoperability. Interoperability is a first-class concept in the structure of the method chunk repository. It not only characterizes method chunks, i.e. procedures to solve interoperability problems, but also interoperability cases, i.e. the presentation of actual problems involving interoperability issues. TG 6 has produced three MCR prototypes. Two experiments were undertaken using the Metis system and one using ConceptBase. The task group attended a two-day intense workshop on Metis. As a result, two experiments with Metis as platform for the method chunk repository are under way and reported in this deliverable. One is realizing the structure of the MCR as specified in this report. The other is an alternative approach that serves as a benchmark and is reported in the appendix. The ConceptBase prototype utilizes the metamodel presented in this deliverable. We have analysed three cases involving various aspects of interoperability. One case is about establishing a broker platform for insurance agents, the second about linking the information systems in the public utility sector, and the third case is establishing the relation of the ATHENA Model-Driven Interoperability Framework to the goals of the MCR. The results of the TG6 have been published at the ISD conference 2006 and the ER conference 2006. Copies of the papers are included in the appendix. The report of the example session with the method chunk repository has been shifted towards deliverable TG6.3 (Tutorial of the MCR). This is the more logical place. We want to emphasize that TG6 was not only busy in drafting concepts, exploring the state of the art, and analyzing cases. We are actually experimenting with a prototype and consider this a valuable contribution to the network. As soon as the prototype is stable, knowledge about interoperability solutions can be coded in this repository and can guide designers of interoperable systems by experience knowledge

A generic architecture for interactive intelligent tutoring systems

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University, 07/06/2001.This research is focused on developing a generic intelligent architecture for an interactive tutoring system. A review of the literature in the areas of instructional theories, cognitive and social views of learning, intelligent tutoring systems development methodologies, and knowledge representation methods was conducted. As a result, a generic ITS development architecture (GeNisa) has been proposed, which combines the features of knowledge base systems (KBS) with object-oriented methodology. The GeNisa architecture consists of the following components: a tutorial events communication module, which encapsulates the interactive processes and other independent computations between different components; a software design toolkit; and an autonomous knowledge acquisition from a probabilistic knowledge base. A graphical application development environment includes tools to support application development, and learning environments and which use a case scenario as a basis for instruction. The generic architecture is designed to support client-side execution in a Web browser environment, and further testing will show that it can disseminate applications over the World Wide Web. Such an architecture can be adapted to different teaching styles and domains, and reusing instructional materials automatically can reduce the effort of the courseware developer (hence cost and time) in authoring new materials. GeNisa was implemented using Java scripts, and subsequently evaluated at various commercial and academic organisations. Parameters chosen for the evaluation include quality of courseware, relevancy of case scenarios, portability to other platforms, ease of use, content, user-friendliness, screen display, clarity, topic interest, and overall satisfaction with GeNisa. In general, the evaluation focused on the novel characteristics and performances of the GeNisa architecture in comparison with other ITS and the results obtained are discussed and analysed. On the basis of the experience gained during the literature research and GeNisa development and evaluation. a generic methodology for ITS development is proposed as well as the requirements for the further development of ITS tools. Finally, conclusions are drawn and areas for further research are identified

GUISET: A CONCEPTUAL DESIGN OF A GRID-ENABLED PORTAL FOR E-COMMERCE ON-DEMAND SERVICES

Conventional grid-enabled portal designs have been largely influenced by the usual functional requirements such as security requirements, grid resource requirements and job management requirements. However, the pay-as-you-use service provisioning model of utility computing platforms mean that additional requirements must be considered in order to realize effective grid-enabled portals design for such platforms. This work investigates those relevant additional requirements that must be considered for the design of grid-enabled portals for utility computing contexts. Based on a thorough review of literature, we identified a number of those relevant additional requirements, and developed a grid-enabled portal prototype for the Grid-based Utility Infrastructure for SMME-enabling Technology (GUISET) initiative – a utility computing platform. The GUISET portal was designed to cater for both the traditional grid requirements and some of the relevant additional requirements for utility computing contexts. The result of the evaluation of the GUISET portal prototype using a set of benchmark requirements (standards) revealed that it fulfilled the minimum requirements to be suitable for the utility context

Developing a Generic Debugger for Advanced-Dispatching Languages

Programming-language research has introduced a considerable number of advanced-dispatching mechanisms in order to improve modularity. Advanced-dispatching mechanisms allow changing the behavior of a function without modifying their call sites and thus make the local behavior of code less comprehensible. Debuggers are tools, thus needed, which can help a developer to comprehend program behavior but current debuggers do not provide inspection of advanced-\ud dispatching-related language constructs. In this paper, we present a debugger which extends a traditional Java debugger with the ability of debugging an advanced-dispatching language constructs and a user interface for inspecting this

A Collaborative Visualization Framework Using JINI™ Technology

It is difficult to achieve mutual understanding of complex information between individuals that are separated geographically. Two well-known techniques commonly used to deal with this difficultly are collaboration and information visualization. This thesis develops a generic flexible framework that supports both collaboration and information visualization. It introduces the Collaborative Visualization Environment (COVE) framework, which simplifies the development of real-time synchronous multi-user applications by decoupling the elements of collaboration from the application. This allows developers to focus on building applications and leave the difficulties of collaboration (i.e., concurrency controls, user awareness, session management, etc.) to the framework. The framework uses an object sharing approach to share information and views between participants in a collaborative session. This approach takes advantage of several Java technologies (i.e., JavaBeans™, Jini™, and JavaSpaces™). JavaBeans™ establish a well-known standard for applications to operate within the framework. Jini™ services provide framework stability and enable code sharing across the network. Objects are shared between remote clients through the JavaSpaces™ service

Adaptive object management for distributed systems

This thesis describes an architecture supporting the management of pluggable software components and evaluates it against the requirement for an enterprise integration platform for the manufacturing and petrochemical industries. In a distributed environment, we need mechanisms to manage objects and their interactions. At the least, we must be able to create objects in different processes on different nodes; we must be able to link them together so that they can pass messages to each other across the network; and we must deliver their messages in a timely and reliable manner. Object based environments which support these services already exist, for example ANSAware(ANSA, 1989), DEC's Objectbroker(ACA,1992), Iona's Orbix(Orbix,1994)Yet such environments provide limited support for composing applications from pluggable components. Pluggability is the ability to install and configure a component into an environment dynamically when the component is used, without specifying static dependencies between components when they are produced. Pluggability is supported to a degree by dynamic binding. Components may be programmed to import references to other components and to explore their interfaces at runtime, without using static type dependencies. Yet thus overloads the component with the responsibility to explore bindings. What is still generally missing is an efficient general-purpose binding model for managing bindings between independently produced components. In addition, existing environments provide no clear strategy for dealing with fine grained objects. The overhead of runtime binding and remote messaging will severely reduce performance where there are a lot of objects with complex patterns of interaction. We need an adaptive approach to managing configurations of pluggable components according to the needs and constraints of the environment. Management is made difficult by embedding bindings in component implementations and by relying on strong typing as the only means of verifying and validating bindings. To solve these problems we have built a set of configuration tools on top of an existing distributed support environment. Specification tools facilitate the construction of independent pluggable components. Visual composition tools facilitate the configuration of components into applications and the verification of composite behaviours. A configuration model is constructed which maintains the environmental state. Adaptive management is made possible by changing the management policy according to this state. Such policy changes affect the location of objects, their bindings, and the choice of messaging system