A Principal Component Analysis Control Chart Method for Catenary Status Evaluation and Diagnosis

<div><i>T</i><sup>2</sup> control chart and SPE control chart of catenary in normal states. (a) Principal component <i>T</i><sup>2</sup> control chart; (b) SPE control chart; (c) conventional multiple <i>T</i><sup>2</sup> control chart.</div>

Advances in Civil Engineering

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Figure 2

Figure 2: A Principal Component Analysis Control Chart Method for Catenary Status Evaluation and Diagnosis 