This paper factors out the common denominator underlying these variants: full decoupling of the communicating entities in time, space, and synchronization. We use these three decoupling dimensions to better identify commonalities and divergences with traditional interaction paradigms. The many variations on the theme of publish/subscribe are classified and synthesized. In particular, their respective benefits and shortcomings are discussed both in terms of interfaces and implementations

This paper describes work in progress to develop a standard for interoperability among high-performance scientific components. This research stems from growing recognition that the scientific community needs to better manage the complexity of multidisciplinary simulations and better address scalable performance issues on parallel and distributed architectures. Driving forces are the need for fast connections among components that perform numerically intensive work and for parallel collective interactions among components that use multiple processes or threads. This paper focuses on the areas we believe are most crucial in this context, namely, an interface definition language that supports scientific abstractions for specifying component interfaces and a ports connection model for specifying component interactions.

. In this paper, we propose ICrafter, a framework for services

Developing requirements for software components, and ensuring these requirements are met by component designs, is very challenging, as very often application domain and stakeholders are not fully known during component development. We introduce a new methodology, aspect-oriented component engineering, that addresses some difficult issues of component requirements engineering by analysing and characterising components based on different aspects of the overall application a component addresses. We give an overview of the aspect-oriented component requirements engineering process, focus on component requirements analysis, specification and reasoning, and briefly discuss tool support. 1. Introduction As software systems become ever more complex, developers use new technologies to help manage development. Component-based systems are one example offering potential for better existing or third party component reuse, compositional systems development, and dynamic and end user reconfiguration...

Software architectures promote development focused on modular building blocks and their interconnections. Since architecture-level components often contain complex functionality, it is reasonable to expect that their interactions will also be complex. Modeling and implementing software connectors thus becomes a key aspect of architecture-based development. Software interconnection and middleware technologies such as RMI, CORBA, ILU, and ActiveX provide a valuable service in building applications from components. The relation of such services to software connectors in the context of software architectures, however, is not well understood. To understand the tradeoffs among these technologies with respect to architectures, we have evaluated several off-the-shelf middleware technologies and identified key techniques for utilizing them in implementing software connectors. Our platform for investigation was C2, a component- and message-based architectural style. By encapsulating middleware functionality within software connectors, we have coupled C2’s existing benefits such as component interchangeability, substrate independence and structural guidance with new capabilities of multi-lingual, multi-process and distributed application development in a manner that is transparent to architects.

PAWS (Parallel Application WorkSpace) is a software infrastructure for use in connecting separate parallel applications within a component-like model. A central PAWS Controller coordinates the linking of serial or parallel applications across a network to allow them to share parallel data structures such as multidimensional arrays. Applications use the PAWS API to indicate which data structures are to be shared and at what points the data is ready to be sent or received. PAWS implements a general parallel data descriptor, and automatically carries out parallel layout remapping when necessary. Connections can be dynamically established and dropped, and can use multiple data transfer pathways between applications. PAWS uses the NEXUS communication library and is independent of the application’s parallel communication mechanism. 1.

This paper motivates the need for AOCE and gives examples of using aspects during component requirements engineering, design and implementation. We begin with an overview of the concept of component aspects, using a component-based process management environment for illustration. We describe aspect-oriented component requirements engineering, and the refinement of component requirements codified by aspects into design-level aspects. Implementation of software components using designlevel aspect information is described, along with various run-time uses of aspects. Tool support is briefly discussed, and we compare and contrast our approach with other component development methods and architectures. We conclude with an overview of current and possible future research directions.

Developing software engineering tools is a difficult task, and the environments in which these tools are deployed continually evolve as software developers' processes, tools and tool sets evolve. To more effectively develop such evolvable environments, we have been using component-based approaches to build and integrate a range of software development tools, including CASE and workflow tools, file servers and versioning systems, and a variety of reusable software agents. We describe the rationale for a component-based approach to developing such tools, the architecture and support tools we have used, some resultant tools and tool facilities we have developed, and summarise possible future research directions in this area. Keywords: component-based software architectures, multiple views, consistency management, tool integration, task automation 1. Introduction Software engineering tools are usually complex applications. Many require multiple view support with appropriate consistency ...

We are currently witnessing the emerging of a new generation of software systems: Federated information systems. Their main characteristic is that they are constructed as an integrating layer over existing legacy applications and databases. They can be broadly classified in three dimensions: the degree of autonomy they allow in integrated components, the degree of heterogeneity between components they can cope with, and whether or not they support distribution. Whereas the communication and interoperation problem has come into a stage of applicable solutions over the past decade, semantic data integration has not become similarly clear. This report

he visualization window (right). Researchers can select UI (user interaction) buttons on many of the modules that allow control and feedback of parameters within a particular module (left). interactively via a component-based visual programming model. SCIRun enables scientists to modify geometric models and interactively change numerical parameters and boundary conditions, as well as to modify the level of mesh adaptation needed for an accurate numerical solution. As opposed to the typical "off-line" simulation mode - in which the scientist manually sets input parameters, computes results, visualizes the results via a separate visualization package, then starts again at the beginning - SCIRun "closes the loop" and allows interactive steering of the design, computation, and visualization phases of a simulation. The BioPSE project seeks to release state-of-the-art software, datasets, and documentation for researchers investigating bioelectric field problems. The immediate applicat