AbstractThis report focuses on improving classification accuracy and reducing computational complexity for human activity recognition problem on public datasets UCI and WISDM. We discussed the benefits of getting access to smartphones in the filed of HAR research. Our experiment indicates that combining AdaBoost M1 algorithm with C4.5 contributes to discriminating several common human activities. Moreover, we showed that it is feasible to reduce computational complexity and achieve high accuracy at the same time by applying correlation-based feature selection.