UbiQuest: A P2P-based Resource Discovery System for Ubiquitous Computing*

Users in ubiquitous computing environments need to find and utilize ambient resources (ubiquitous services or devices which provide ubiquitous services). In ubiquitous computing, users and resources are highly mobile, and furthermore, the attributes of ubiquitous resources may change dynamically; the static/centralized resource management systems such as conventional DNS are inappropriate for ubiquitous computing. The new resource discovery system should be independent of specific protocols, service providers and types of devices, and should be capable of finding resources only by using the attribute information of the wanted resource. This paper presents a novel resource discovery system, UbiQuest. UbiQuest has a simple and flexible architecture and provides a general-purpose/semantic-free resource discovery service. To support distributed resource management and discovery, UbiQuest adopts a DHT-based overlay network architecture. Despite the inherent rigidness of DHT, UbiQuest supports range queries and flexible search by using logical operators as well as the discovery of dynamically changing resources. The performance of the UbiQuest system is evaluated by simulation experiments, which reveal that UbiQuest can handle dynamically changing resources more efficiently.