Part 2: Data Capture and Transmission to a Back-End Server: We propose to write a comprehensive mobile software suite that will allow the mobile phone to use Bluetooth to pair with wireless monitoring devices to collect vital health and behavioral data along with reading the built-in GPS data. The BodyMedia and MemSensse units will provide accelerometry data on physical activity and sleep. These measures will be validated in our physical activity lab against the Actigraph accelerometer (which has been extensively validated in youth) and Continuous Observation using the SOFIT system, a gold standard for physical activity measurement in youth 32, 33. By using time stamps the sensor data from Accelerometer can be correlated to the vital signs data collected from wearable sensors. We will use the data collected from all these sensors to automatically classify the user's activity. In particular, the software creates user specific movement signatures to account for differences in user's gait, walking/running/bicycling speed, usual route taken between work and home etc. The software will be able to use a combination of GPS and accelerometers to recognize the differences between driving on road and walking. This sensor information will be recorded continuously on the local storage on the mobile phone. For reference, our mobile device platform has an 8GB in-built flash memory that can be used for storing sensor information. Table 1 shows the approximate data rate of sensors. Using these data rates, we estimate that our 8GB local storage can store approximately 1000 days worth of data.