Current Middleware Technologies Research Articles

Multicast middleware for performance and topology analysis of multimedia grids

Since multicast reduces bandwidth consumption in multimedia grid computing, the middleware for monitoring the performance and topology of multicast communications is important to the design and management of multimedia grid applications. However, the current middleware technologies for multicast performance monitoring are still far from attaining the level of maturity and there lacks consistent approaches to obtain the evaluation data for multicast. In this study, to serve a clear guide for the design and implementation of the multicast middleware, two algorithms are developed for organising all constituents in multicast communications and analysing the multicast performance in two topologies – ‘multicast distribution tree’ and ‘clusters distribution’, and a definitive set of corresponding metrics that are comprehensive yet viable for evaluating multicast communications are also presented. Instead of using the inference data from unicast measurements, in the proposed middleware, the measuring data of multicast traffic are obtained directly from multicast protocols in real time. Moreover, this study makes a middleware implementation which is integrated into a real access grid multicast communication infrastructure. The results of the implementation demonstrate the substantial improvements in the accuracy and real time in evaluating the performance and topology of multicast network.

A qualitative human-centric evaluation of flexibility in middleware implementations

Today middleware is much more powerful, more reliable and faster than it used to be. Nevertheless, for the application developer, the complexity of using middleware platforms has increased accordingly. The volume and variety of application contexts that current middleware technologies have to support require that developers be able to anticipate the widest possible range of execution environments, desired and undesired effects of different programming strategies, handling procedures for runtime errors, and so on. This paper shows how a generic framework designed to evaluate the usability of notations (the Cognitive Dimensions of Notations Framework, or CDN) has been instantiated and used to analyze the cognitive challenges involved in adapting middleware platforms. This human-centric perspective allowed us to achieve novel results compared to existing middleware evaluation research, typically centered around system performance metrics. The focus of our study is on the process of adapting middleware implementations, rather than in the end product of this activity. Our main contributions are twofold. First, we describe a qualitative CDN-based method to analyze the cognitive effort made by programmers while adapting middleware implementations. And second, we show how two platforms designed for flexibility have been compared, suggesting that certain programming language design features might be particularly helpful for developers.

Adaptive resource management in middleware: a survey

Current middleware technologies cannot meet the demands of new application areas, such as embedded and mobile systems, that require mechanisms for dealing with a changing environment. This article reviews several approaches for providing adaptive resource management for middleware. Current middleware technologies, such as the Common Object Request Broker Architecture (CORBA) and .NET (http://msdn.microsoft.com/net), mask system and network heterogeneity problems and alleviate the inherent complexity of distributed systems in many application areas. However, the recent emergence of new application areas for middleware, such as embedded systems, real-time systems, and multimedia, imposes challenges that few existing middleware platforms can meet. In particular, because they impose greater resource-sharing and dynamism demands, these application areas require more complex and sophisticated middleware. Resource sharing must be controlled and predictable to ensure that activities running on the same middleware instance have adequate resources.