Applying Log Data to Context-Awareness in Home Network System

In the conventional context-aware services of the home network system (HNS), every context has been defined by current (or recent) situations only. Considering past situations in a house would significantly extend the expressive power of the context-aware services. In this paper, we propose a new type of context, called log context, by using house log of the HNS, extensively. The log context is defined with both the current and past situations, where the current situation is obtained by sensors or device status of the HNS while the past situations are derived by queries to the house log. We also develop a system that can derive the log contexts within an actual HNS. To manage individual log contexts efficiently, the system is designed by four layers: application layer, log context layer, log query layer, and DB connector layer. To evaluate the execution performance of our system, we have conducted an experiment which measures execution time of some variety of log queries