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Class imbalance is prevalent in many real world datasets. It occurs when there are significantly fewer examples in one or more classes in a dataset compared to the number of instances in the remaining classes. When trained on highly imbalanced datasets, traditional machine learning techniques can often simply ignore the minority class(es) and label all instances as being of the majority class to maximize...
This paper considers the use of feature selection within the state detection module for an ocean turbine condition monitoring system. The goal is to reduce the quantity of data to be processed while maintaining or improving state detection capabilities. Five feature selection techniques (Chi-squared, Information Gain, Signal-To-Noise, AUC and PRC) are evaluated based on their effects on four widely...
Data fusion is the process of combining data from multiple sources, allowing for a more complete and accurate assessment of a system or an environment than could have been otherwise provided by a single source. This paper considers and empirically evaluates a decision-level data fusion method for enabling reliable ocean turbine state detection based on data from multiple sensors. This method involves...
An ocean turbine extracts the kinetic energy from ocean currents to generate electricity. Vibration signals from the turbine hold a wealth of information regarding its state, and detecting changes in these signals is crucial to the timely detection of faults. Wavelet transforms provide a means of analyzing these complex signals and extracting features which are representative of the signal. Feature...
An ocean turbine extracts the kinetic energy from ocean currents to generate electricity. Machine Condition Monitoring(MCM) / Prognostic Health Monitoring (PHM) systems allow for self-checking and automated fault detection, and are integral in the construction of a highly reliable ocean turbine. This paper presents an onshore test platform for an ocean turbine as well as a case study showing how machine...
An ensemble is a collection of independent processes, each tasked with drawing potentially differing conclusions about the same data. Using Petri nets, this paper formally describes how ensembles are organized and their behavior coordinated to effect distributed discrete event control of an ocean turbine prototype. Compositions, duals, reverses, and cliques formed over known Petri net graphs comprise...
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