| 摘要 |
PROBLEM TO BE SOLVED: To provide a process monitoring method by an MT method using principal component analysis, the process monitoring method being capable of unequivocally determining the number of principal components. SOLUTION: In the process monitoring method, a principal component is set based upon data acquired in manufacturing processes of a product, the square value MD2 of a Mahalanobis distance is calculated based upon the principal component, and the quality of the product is predicted based upon MD2. Then the number (s) of principal components is determined to be a value (e) at which an indicator function IND(e) has a minimum value, where (g) is the number of principal components generated when principal component analysis is carried out with respect to a correlation coefficient matrix R between items of data, (e) is an integer of 1 to (g), (n) is the number of sets of data, (p) is the number of items,λ<SB>j</SB>is a j-th eigen value, ER is an error amount, and IND(e) the indicator function associated with the error amount ER. COPYRIGHT: (C)2009,JPO&INPIT
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