Time-domain global similarity method for automatic data cleaning for multi-channel measurement systems in magnetic confinement fusion devices

Abstract

To guarantee the availability and reliability of data source in Magnetic Confinement Fusion (MCF) devices, incorrect diagnostic data, which cannot reflect real physical properties of measured objects, should be sorted out before further analysis and study. Traditional data sorting cannot meet the growing demand of MCF research because of the low-efficiency, time-delay, and lack of objective criteria. In this paper, a Time-Domain Global Similarity (TDGS) method based on machine learning technologies is proposed for the automatic data cleaning of MCF devices. The aim of traditional data sorting is to classify original diagnostic data sequences. The lengths and evolution properties of the data sequences vary shot by shot. Hence the classification criteria are affected by many discharge parameters and are different in various discharges. The focus of the TDGS method is turned to the physical similarity between data sequences from different channels, which are more independent of discharge parameters. The complexity arisen from real discharge parameters during data cleaning is avoided in the TDGS method by transforming the general data sorting problem into a binary classification problem about the physical similarity between data sequences. As a demonstration of its application to multi-channel measurement systems, the TDGS method is applied to the EAST POlarimeter–INTerferometer (POINT) system. The optimal performance of the method evaluated by 24-fold cross-validation has reached 0.9871 ± 0.0385.