Date Added: Jan 2010
Middleware systems have emerged in recent years to support applications in heterogenous and ubiquitous computing environments. Specifically, future middleware platforms are expected to provide Quality-of-Service (QoS) support, which is required by a new generation of QoS-sensitive applications such as media streaming and e-commerce. This paper presents four key aspects of a QoS-aware middleware system. First, QoS specification to allow description of application behavior and QoS parameters; Second, QoS translation and compilation to translate specified application behavior into candidate application configurations for different resource conditions; Third, QoS setup to appropriately select and instantiate a particular configuration; Finally, QoS adaptation to adapt to runtime resource fluctuations. This paper also provides a comparison of existing QoS-aware middleware systems in these four aspects.