C2FHAR: Coarse-to-Fine Human Activity Recognition With Behavioral Context Modeling Using Smart Inertial Sensors

Smart sensing devices are furnished with an array of sensors, including locomotion sensors, which enable continuous and passive monitoring of human activities for the ambient assisted living. As a result, sensor-based human activity recognition has earned significant popularity in the past few years. A lot of successful research studies have been conducted in this regard. However, the accurate recognition of <italic>in-the-wild</italic> human activities in real-time is still a fundamental challenge to be addressed as human physical activity patterns are adversely affected by their behavioral contexts. Moreover, it is essential to infer a user & x2019;s behavioral context along with the physical activity to enable context-aware and knowledge-driven applications in real-time. Therefore, this research work presents & x201C;C2FHAR & x201D;, a novel approach for <italic>coarse-to-fine human activity recognition in-the-wild</italic>, which explicitly models the user & x2019;s behavioral contexts with activities of daily living to learn and recognize the fine-grained human activities. For addressing real-time activity recognition challenges, the proposed scheme utilizes a multi-label classification model for identifying <italic>in-the-wild</italic> human activities at two different levels, i.e., <italic>coarse</italic> or <italic>fine-grained</italic>, depending upon the real-time use-cases. The proposed scheme is validated with extensive experiments using heterogeneous sensors, which demonstrate its efficacy.