A principled approach to supporting adaptation in distributed mobile environments

Abstract

To support multimedia applications in mobile environments, it will be necessary for applications to be aware of the underlying environmental conditions, and also to be able to adapt their behaviour and that of the underlying platform as such conditions change. Many existing distributed systems platforms support such adaptation only in a rather ad hoc manner. This paper presents a principled approach to supporting adaptation through the use of reflection. More specifically, the paper introduces a languageindependent, component-based reflective architecture featuring a per-component meta-space, the use of meta-models to structure meta-space, and a consistent use of component graphs to represent composite components. The paper also reports on a quality of service management framework, providing sophisticated support for monitoring and adaptation functions. Finally, the paper describes a prototype implementation of this architecture using the object-oriented programming language Python.

CAMPUS: A middleware for automated context-aware adaptation decision making at run time

“…To avoid the recompilation required in Odyssey, many application-aware context-aware middleware systems, such as [4,7,8], employ the reflective mechanism to dynamically reconfigure the application based on descriptive adaptation policies. Importantly, these policies can be changed after the deployment of applications.…”

An Infrastructure for Adaptable Middleware

“…Open-ORB [12,4] is a project whose goal is to define an architecture for adaptable middleware, particularly in the domain of multimedia applications. It is based on a component model which includes explicit dependencies and interaction between components, support for continuous media (streaming), and an event notification model.…”

“…The next step is to make this middleware more flexible, and able to be adapted -or even better to adapt itself -to environmental changes. Although current industrial middleware implementations ( [1,2,3]) do not take into account the dynamic execution conditions, previous works on adaptable middleware [4,5] have shown the viability of this approach.…”

Exploiting Reflection to Design and Manage Services for an Adaptive Resource Management System

“…Today, reflection is successfully applied at the architectural level too [10]. Generally, architectural reflection may introduce additional layers [3,4,5,6,15] or software components [13,16] between the representation of a system and applications. Their role is to enable applications to adapt to the systems' features and, vice-versa, systems to adapt (whenever possible) to the applications' requirements.…”