Indoor-Outdoor Activity Recognition by a Smartphone

It is increasingly important to recognize daily activity pattern in order to detect early sign of dementia in the aging society. This paper shows indoor-outdoor activity recognition using only a smartphone. We developed an indoor living activity recognition engine and an outdoor migration activity recognition engine, and combined them into an Android (TM) application. The former recognizes not only "resting" or "walking" but also user's various living activities such as "vacuuming" and "brushing teeth" by using a built-in accelerometer and a built-in microphone. The latter engine recognizes the user's means of migration, namely, "resting," "walking," "running," and "boarding" by using a built-in accelerometer. It enables users to continuously recognize indoor-outdoor activities by switching between the two engines depending on an acquisition condition of GPS satellites.