Cosine Similarity Measure between Vague Sets and Its Application of Fault Diagnosis

In order to propose a novel cosine similarity measure between vague sets and to apply it to the fault diagnosis of turbine, a new similarity measure value between a testing sample and the knowledge of system faults is evaluated in the vibration fault diagnosis of turbine. The testing sample is near to a type of fault knowledge if the measure value is big. Thus, the type of vibration fault is determined according to the maximum measure value (more than some threshold). The fault-diagnosis problems of the turbine are investigated by use of the proposed cosine similarity measure. The results demonstrate that the proposed method not only diagnoses the main fault types of the turbine, but also provides useful information for multi-fault analyses and future trends. Therefore, the proposed method is reasonable and effective and provides another useful tool for fault analyses.