Spacelog Concept and Issues for Novel u-Services in Smart Spaces

Spacelog is a continuous collection of existence states and activity experiences of various entities in a physical environment, and it can be regarded as a special database or conceptually seen as a memory organ specifically for a real spatial site such as a home and a laboratory. Different from lifelog that is a personal database for a single individual, the entities in the spacelog cover multiple forms including people, facilities, artifacts, and space-related states in a site. This paper first explains the spacelog concept as compared with concepts of log, lifelog, monitoring cameras and context history, then discusses the fundamental features of the spacelog as well as related technique issues faced to develop spacelog systems, and finally describes the possible novel services and applications using spacelog in smart spaces.