A New Methodology of QoS Evaluation and Service Selection for Ubiquitous Computing

Abstract

Ubiquitous Computing (UbiComp) has become a new computing model in computer systems. However, the characteristics of UbiComp, such as context-awareness, mobility and resource-limitedness, pose challenges for service infrastructure to provide effective service provision. In this paper, we present a suit of user-oriented models and methods that support dynamic Quality of Service (QoS) evaluation and adaptive service selection for UbiComp: 1) We propose a user-oriented QoS model with hierarchical structure to achieve scalability and flexibility; 2) An extended context model with time dimension is employed in QoS evaluation; 3) To capture the weights of quality criteria, we design a user preference model based on linguistic variable; 4) We also model QoS evaluation and service selection as the combination of first order logic inference and hierarchical fuzzy logic evaluation. A case study is presented to demonstrate the effectiveness of our approach.