Towards a re-engineering method for web services architectures

Recent developments in Web technologies – in particular through the Web services framework – have greatly enhanced the flexible and interoperable implementation of service-oriented software architectures. Many older Web-based and other distributed software systems will be re-engineered to a Web services-oriented platform. Using an advanced e-learning system as our case study, we investigate central aspects of a re-engineering approach for the Web services platform. Since our aim is to provide components of the legacy system also as services in the new platform, re-engineering to suit the new development paradigm is as important as re-engineering to suit the new architectural requirements

mPower: A component-based development framework for multi-agent systems to support business processes

One of the obstacles preventing the widespread adoption of multi-agent systems in industry is the difficulty of implementing heterogeneous interactions among participating agents via asynchronous messages. This difficulty arises from the need to understand how to combine elements of various content languages, ontologies, and interaction protocols in order to construct meaningful and appropriate messages. In this paper mPower, a component-based layered framework for easing the development of multi-agent systems, is described, and the facility for customising the components for reuse in similar domains is explained. The framework builds on the JADE-LEAP platform, which provides a homogeneous layer over diverse operating systems and hardware devices, and allows ubiquitous deployment of applications built on multi-agent systems both in wired and wireless environments. The use of the framework to develop mPowermobile , a multi-agent system to support mobile workforces, is reported

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

Rapid Modeling, Prototyping, and Generation of Digital Libraries- A Theory-Based Approach

Despite some development in the area of DL architectures and systems, there is still little support for the complete life cycle of DL development, including requirements gathering, conceptual modeling, rapid prototyping, and code generation and reuse. Even when partially supported, those activities are uncorrelated within the current systems, which can lead to inconsistencies and incompleteness. Moreover, the current few existing approaches are not supported by comprehensive and formal foundations and theories, which brings problems of interoperability and makes it extremely difficult to adapt and tailor systems to specific societal preferences and needs of the target community. In this paper, having the 5S formal theoretical framework as support, we present an architecture and a family of tools that allow rapid modeling, prototyping, and generation of digital libraries. 5S stands for Streams, Structures, Spaces, Scenarios, and Societies and is our formal theory for DLs. 5SL is a domain-specific, declarative language for DL conceptual modeling. 5SGraph is a visual modeling tool that helps designers to model a digital library without knowing the theoretical foundations and the syntactical details of 5SL. Furthermore, 5SGraph maintains semantic constraints specified by a 5S metamodel and enforces these constraints over the instance model to ensure semantic consistency and correctness. 5SGraph also enables component reuse to reduce the time and efforts of designers. 5SLGen is a DL generation tool that takes specifications in 5SL and a set of component pools and generates portions of a running DL system. The outputs of 5SLGen include user interface prototypes, in a generic UI markup language, for validation of services behavior and workflow representations of the running system, generated to support the desired scenarios

Using formal methods to develop WS-BPEL applications

In recent years, WS-BPEL has become a de facto standard language for orchestration of Web Services. However, there are still some well-known difficulties that make programming in WS-BPEL a tricky task. In this paper, we firstly point out major loose points of the WS-BPEL specification by means of many examples, some of which are also exploited to test and compare the behaviour of three of the most known freely available WS-BPEL engines. We show that, as a matter of fact, these engines implement different semantics, which undermines portability of WS-BPEL programs over different platforms. Then we introduce Blite, a prototypical orchestration language equipped with a formal operational semantics, which is closely inspired by, but simpler than, WS-BPEL. Indeed, Blite is designed around some of WS-BPEL distinctive features like partner links, process termination, message correlation, long-running business transactions and compensation handlers. Finally, we present BliteC, a software tool supporting a rapid and easy development of WS-BPEL applications via translation of service orchestrations written in Blite into executable WS-BPEL programs. We illustrate our approach by means of a running example borrowed from the official specification of WS-BPEL

A distributed solution to software reuse

Reuse can be applied to all stages of the software lifecycle to enhance quality and to shorten time of completion for a project. During the phases of design and implementation are some examples of where reuse can be applied, but one frequent obstruction to development is the building of and the identifying of desirable components. This can be costly in the short term but an organisation can gain the profits of applying this scheme if they are seeking long-term goals. Web services are a recent development in distributed computing. This thesis combines the two research areas to produce a distributed solution to software reuse that displays the advantages of distributed computing within a reuse system. This resulted in a web application with access to web services that allowed two different formats of component to be inserted into a reuse repository. These components were searchable by keywords and the results are adjustable by the popularity of a component’s extraction from the system and by user ratings of it; this improved the accuracy of the search. This work displays the accuracy, usability, and speed of this system when tested with five undergraduate and five postgraduate students

From Method Fragments to Method Services

In Method Engineering (ME) science, the key issue is the consideration of information system development methods as fragments. Numerous ME approaches have produced several definitions of method parts. Different in nature, these fragments have nevertheless some common disadvantages: lack of implementation tools, insufficient standardization effort, and so on. On the whole, the observed drawbacks are related to the shortage of usage orientation. We have proceeded to an in-depth analysis of existing method fragments within a comparison framework in order to identify their drawbacks. We suggest overcoming them by an improvement of the ?method service? concept. In this paper, the method service is defined through the service paradigm applied to a specific method fragment ? chunk. A discussion on the possibility to develop a unique representation of method fragment completes our contribution

Abstract Interactions and Interaction Refinement in Model-Driven Design

In a model-driven design process the interaction between application parts can be described at various levels of platform-independence. At the lowest level of platform-independence, interaction is realized by interaction mechanisms provided by specific middleware platforms. At higher levels of platform-independence, interaction must be described in such a way that it can be further refined and realized onto a number of different middleware platforms, each with its particular interaction mechanisms and implementation constraints. In this paper, we investigate concepts that support interaction design at various levels of middleware-platform-independence. Also, we propose design operations for interaction refinement. The application of these operations to source designs results in target designs that take into account implementation constraints imposed by platforms, while preserving characteristics prescribed in source designs