Silhouette criterion for automatic grouping algorithm of spaceship electronic components

Due to the development of the space industry, expansion of functions of spacecrafts and increasing its service life, matter of its reliability are becoming very important. Therefore, it is necessary to provide a high quality of electronic components in space production and pay attention to the homogeneity of its specifications to ensure a high level of consistency of its work as the part of the device. This requires a complex control system, testing and automatic classification of arriving components, which aims to select components manufactured within the same production batch from providing components. Besides, the results of the selective destroying physical analysis can be extended to all batches of components, only being confident in homogeneity of this batch. This paper is devoted to one aspect of such a system - the definition of the estimated number of production batches in a composite party of components. The task of determination of number of groups is one of the most difficult aspects of data classification. There is significant amount of various criteria for evaluation of expected number of groups in literature today. We studied the effectiveness of various criteria, and concluded that the method based on the Silhouette criterion is very effective to solve the problem of automatic grouping, particularly for grouping of spacecraft electronic components on homogeneous production batches. We paid special attention to the “outliers” - elements, which characteristics are far from the characteristics of the major amount of classified elements. We made experimental verification of the method on real data and showed that the maximum of Silhouette criterion corresponds to the actual number of production batches in the examination selection, representing the combined batch collected from the elements made as a part of several homogeneous production lots. The proposed method for estimating the number of production lots is based on the test data from a specialized test center and does not require additional testing. Thus, this method is suitable for implementation in manufacturing process to improve the quality of spacecraft electronic components without considerable expenses.