Enabling Identification and Behavioral Sensing in Homes using Radio Reflections

Understanding users' behavior at home is central to behavioral research. For example, social researchers are interested in studying domestic abuse, and healthcare professionals are interested in caregiver-patient interaction. Today, such studies rely on diaries and questionnaires, which are subjective, erroneous, and hard to sustain in longitudinal studies. We introduce Marko, a system that automatically collects behavior-related data, without asking people to write diaries or wear sensors. Marko transmits a low power wireless signal and analyses its reflections from the environment. It maps those reflections to how users interact with the environment (e.g., access to medication cabinet) and with each other (e.g., watch TV together). It provides novel algorithms for identifying who-does-what, and bootstrapping the system in new homes without asking users for new annotations. We evaluate Marko with a one-month deployment in six homes, and demonstrate its value for studying couple relationships and caregiver-patient interaction.