Abstract: Unsupervised learning is a technique to organize the data into meaningful way having similarity. Cluster analysis is the study of clustering techniques and algorithms which are helpful to discover important patterns from fundamental data without knowledge of category label for further analysis. k-Means algorithm is one of the most popular clustering algorithm among all partition based clustering algorithm to partition a dataset into meaningful patterns. k-Means algorithm suffers from the problem of specifying the number of clusters in advance and often converges to local minima and therefore resulted clusters are heavily dependent on initial centroids. Various methods have been proposed for automatic detection of initial centroids to improve the performance and efficiency of k-Means algorithm. This paper presents an overview of clustering, clustering techniques and algorithms, addressing problems of k-Means algorithm, comparison of different methods for automatic detection of initial.

• Publication Date: 03-Jun-2011
• DOI: 10.15224/978-981-07-1847-3-1027
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Abstract: The direct torque control (DTC) scheme for a matrix-converter-fed induction motor drive system is a high performance motor control scheme with fast torque and flux responses. The main disadvantage of conventional DTC is electromagnetic torque ripple. Matrix converter is a single-stage ac-ac power conversion device without dc-link energy storage elements. Switching pattern of the different switches of matrix converter are generated by direct torque control scheme and by suitably selecting switching pattern, the electromagnetic torque ripple of the motor is effectively reduced. By this switching strategy, the advantages of the DTC schemes and the benefits of the matrix converters can be combined and as a result, a satisfactory servo drive can be achieved. This paper presents a literature survey on the direct torque control of matrix converter fed induction motor drive. Different techniques for DTCIMD are described and attempt is made to provide a guideline and quick reference for the res

• Publication Date: 12-Mar-2012
• DOI: 10.15224/978-981-07-1847-3-896
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