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Out‐of‐Control Signals in Three‐Part Compositional T 2 Control Chart
Author(s) -
VivesMestres Marina,
DaunisiEstadella Josep,
MartínFernández JosepAntoni
Publication year - 2014
Publication title -
quality and reliability engineering international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 62
eISSN - 1099-1638
pISSN - 0748-8017
DOI - 10.1002/qre.1583
Subject(s) - control chart , chart , control (management) , transformation (genetics) , computer science , signal (programming language) , constant (computer programming) , interpretation (philosophy) , process (computing) , multivariate statistics , shewhart individuals control chart , process control , statistics , data mining , mathematics , artificial intelligence , machine learning , ewma chart , chemistry , programming language , biochemistry , gene
Interpretation of out‐of‐control signals in multivariate control charts is a persistent problem. Identifying the variables contributing to the signal is of crucial importance for process control. Both procedures turn out to be more complicated when observations are compositions (variables adding to a constant sum). Compositional T 2 control chart ( T C 2 ) is suitable for monitoring compositions because it is based on a transformation of the data, which moves it from restricted to real space. This paper proposes a method for interpreting the out‐of‐control signals of the T C 2 control chart for three‐part compositions on the basis of an appropriate selection of the transformation. An example of industrial application illustrates the introduced techniques. Copyright © 2013 John Wiley & Sons, Ltd.