A control-based middleware framework for quality-of-service adaptations

In heterogeneous environments with performance variations present, multiple applications compete and share a limited amount of system resources and su ffer from variations in resource availability. These complex applications a re desired to adapt themselves and to adjust their resource demands dynamic ally, On one hand, current adaptation mechanisms built within an applicatio n cannot preserve global properties such as fairness; on the other hand, ad aptive resource management mechanisms built within the operating system are not aware of data semantics in the application. In this paper, we present a novel middleware control framework to enhance the effectiveness of qualit y-of-service (QoS) adaptation decisions by dynamic control and reconfigurat ion of internal parameters and functionalities of a distributed multimedia application. Our objective is to satisfy both system-pwide properties (such as fairness among concurrent applications) and application-specific requir ements (such as preserving the critical performance criteria). The framewor k is modeled by the task control model and the fuzzy control model, based o n rigorous results from the control theory, and verified by the controllabi lity and adaptivity of a distributed visual tracking application, The resul ts show validation of the framework, i.e., critical application quality par ameters can be preserved via controlled adaptation.