Context-Based Qos Model and its Application in Ubiquitous Computing

In the mobile and resource-constrained ubiquitous computing environments, we need an effective quality of service (QoS) model to support dynamic service selection in tune with the variation of context. To serve this purpose, we explore the concept of QoS and propose a context-based QoS model with hierarchical structure. Based on the context model, the QoS model can identify different types of context and evaluate the impact of context upon service selection through first-order logic inference and fuzzy logic evaluation. Quantitative methods are employed to quantify quality factors. The application of the model is demonstrated in the process of service selection. Two experiments have been conducted to evaluate the model. The result of the experiments has proved that with the application of the QoS model, service selection is of better scalability and performance