Exer-model: A User Model for Scrutinising Long-term Models of Physical Activity from Multiple Sensors

A user model that is built from the data of multiple physical activity sensors has the potential to enable people to answer important questions about their long-term physical activity. Our work provides a way to do this for the case of exercise from virtual reality gaming and from incidental daily walking. Our approach is based two parts: 1) a carefully designed a user model ontology, Exer-model; 2) an interface for navigating the model and comparing components of the model. We evaluated the Exer-model ontology and the scrutiny interface in a study with 16 users: 8 viewing their own user models, from 8 weeks of their sensor data, and the other 8 scrutinising the model of a hypothetical user. Our core contributions are the insights about designing the ontologies and interfaces for scrutable user models from multiple physical activity sensors.