“…Next step is to select the optimal set of features using feature selection methods such as windowing technique, kernel discriminant analysis [122], minimal redundancy maximal relevance heuristic [126], Correlation based Feature Selection [125,121]. Afterwards, the selected features are fed into supervised classifiers including Naive Bayes [122], SVM [124,126], Decision Trees [121], Neural Networks [15], k-Nearest Neighbor [125] or unsupervised clustering methods such as LDA, MFA [127] depending on the availability of the labels for each class of activity to detect the activities including static physical activities like sitting, standing, lying, watching TV [122,15], and dynamic like walking and up stairs [122], down stairs, running [125], ramp up and down [121]. Table 6 summarizes our analysis of the literature on feature-level sensor fusion in activity recognition systems; for the sake of clarity, we reported only the most representative (in terms of citations and novelty) analyzed works.…”