A fundamental step towards artificial intelligence is to provide learning processes with the ability to constantly adapt to continuously evolving environments and to deal with the ever-increasing quantity of data that these environments generate. This is the case in sensor-rich environments that characterize the Internet of Things applications such as human activity recognition (HAR). In this contribution, we propose to improve HAR systems with domain knowledge composition. Three models encoding different domain knowledge are used: (1) a model of the influence of data sources on human activities, (2) a model of the interactions between data sources, and (3) a model of the transitions between human activities.