“…This field focuses on the definition and application of algorithms that can be trained on data to model underlying patterns [11,73,77,88]. Machine learning approaches can be applied to many different research fields, including biomedical science [59,84,95,126], natural language understanding [22,83], [97] anomaly detection [17], image classification [71], database knowledge discovery [32], robot learning [3], online advertising [86], time series forecasting [13], brain computer interfacing [78] and many more [98]. To train these algorithms, it is necessary to define an objective function, which gives a scalar measure of the algorithm's performance [77,116].…”