A Two-Stage Composition Method for Danger-Aware Services Based on Context Similarity

• Published in: IEICE Transactions on Information and Systems Vol. E93.D; no. 6; pp. 1521 - 1539
• Main Authors: WANG, Junbo, CHENG, Zixue, JING, Lei, OTA, Kaoru, KANSEN, Mizuo
• Format: Journal Article
• Language: English
• Published: Oxford The Institute of Electronics, Information and Communication Engineers 2010; Oxford University Press
• Subjects: Acceptability; Applied sciences; Composing; composition of contexts; context similarity; context-aware services; danger-aware; Detection, estimation, filtering, equalization, prediction; Dynamical systems; Dynamics; Exact sciences and technology; Indoor; Information, signal and communications theory; Networks; Reasoning; Signal and communications theory; Signal, noise; Similarity; Telecommunications; Telecommunications and information theory; Teleprocessing networks. Isdn; ubiquitous computing; Valuation and optimization of characteristics. Simulation; Multiple access; Multistage method; Useful information; Similarity; Adaptive system; Ubiquitous computing; Context aware; context-aware services; Network service; composition of contexts; danger-aware; Implementation; Information service; Accuracy; Indoor installation; Computer network; context similarity; Sensor array; Multistage circuit; Signal detection; Telecommunication services
• ISSN: 0916-8532; 1745-1361; 1745-1361
• DOI: 10.1587/transinf.E93.D.1521

Context-aware systems detect user's physical and social contexts based on sensor networks, and provide services that adapt to the user accordingly. Representing, detecting, and managing the contexts are important issues in context-aware systems. Composition of contexts is a useful method for these works, since it can detect a context by automatically composing small pieces of information to discover service. Danger-aware services are a kind of context-aware services which need description of relations between a user and his/her surrounding objects and between users. However when applying the existing composition methods to danger-aware services, they show the following shortcomings that (1) they have not provided an explicit method for representing composition of multi-user' contexts, (2) there is no flexible reasoning mechanism based on similarity of contexts, so that they can just provide services exactly following the predefined context reasoning rules. Therefore, in this paper, we propose a two-stage composition method based on context similarity to solve the above problems. The first stage is composition of the useful information to represent the context for a single user. The second stage is composition of multi-users' contexts to provide services by considering the relation of users. Finally the danger degree of the detected context is computed by using context similarity between the detected context and the predefined context. Context is dynamically represented based on two-stage composition rules and a Situation theory based Ontology, which combines the advantages of Ontology and Situation theory. We implement the system in an indoor ubiquitous environment, and evaluate the system through two experiments with the support of subjects. The experiment results show the method is effective, and the accuracy of danger detection is acceptable to a danger-aware system.