High level activity annotation of daily experiences by a combination of a wearable device and Wi-Fi based positioning system

Many people would like to record and manipulate their experiences effectively. However, efficient summarization to show ldquowhat, when and whererdquo we did in our daily lives is still an open issue in life log applications. In conventional approaches, many sensors were attached to a human body to solve this problem. However, this is not practical for daily use. In this paper, we propose a simple solution in which a user wears two devices: a single life-logging device SenseCam [1] hung by neck and a Wi-Fi enabled PDA. The location data and low-level activity are analyzed by a Wi-Fi based positioning system. Then, high-level activity classification is conducted using the wearable device along with a refinement process considering the time consistency. Experimental results demonstrated high recall and precision rates as much as 81% and 85% respectively, on average.