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13 results on '"Lee, Guan-wei"'

9. Long Short-Term Memory Autoencoder for Anomaly Detection in Rails Using Laser Doppler Vibrometer Measurements

Author

Yang, Chi, Kaynardag, Korkut, Lee, Guan-Wei, and Salamone, Salvatore

Abstract

This study presents an application of a long short-term memory autoencoder (LSTM AE) for the detection of broken rails based on laser Doppler vibrometer (LDV) measurements. This work is part of an ongoing project aimed at developing a noncontact damage detection system using LDV measurements. The damage detection system consists of two LDVs mounted on a moving rail car to measure vibrations induced on the rail head. Field tests were carried out at the Transportation Technology Center (TTC) in Pueblo, CO, to collect the vibrational data. This study focused on the detection of broken rails. To simulate the reflected and transmitted waves induced by the broken rail, a welded joint was used. The data were collected from moving LDV measurements, in which the train was operating at three different speeds: 16 km/h (10 mph), 32 km/h (20 mph), and 48 km/h (30 mph). After obtaining the data, filtering and signal processing were applied to obtain the signal features in time and frequency domains. Next, correlation analysis and principal component analysis were carried out for feature selection and dimension reduction to determine the input used to train and test the LSTM AE model. In this study, the LSTM AE models were trained based on different data sets for anomaly detection. Consequently, an automatic anomaly detection approach for anomaly detection based on the LSTM AE model was evaluated. The results show that the LSTM AE model can efficiently detect the anomaly based on the selected features at three different speeds.

Published
2025
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13. Are the Color Gamuts of CRT and LCD Triangular? An Experimental Study

Author

NATIONAL TSING HUA UNIV HSIN-CHU (TAIWAN) DEPT OF INDUSTRIAL ENGINEERING, Lee, Guan-wei, Wen, Chao-hua, NATIONAL TSING HUA UNIV HSIN-CHU (TAIWAN) DEPT OF INDUSTRIAL ENGINEERING, Lee, Guan-wei, and Wen, Chao-hua

Abstract

Color LCD (Liquid Crystal Display) has been widely used for personal computers (PC) and video monitors because of its light weight, small volume, low power consumption and so on. Color reproductions for LCD panels are different from that of CRT (Cathode Ray Tube) display. This study describes the difference of color gamuts in different luminance level and the accuracy of color between CRT and LCD. In the present study, the reproduction color gamuts on the chromaticity diagram are measured in three types of displays, including two CRT types (BARCO Reference Calibrator Plus and ViewSonic PT775) and one LCD type (NEC MultiSync LCD 200). In the experiment, the tristimulus values XYZ for the combinations of three primary colors R(red), G(green), B(blue) were measured by varying the input digital levels. The digital levels which varied from 0 to 255 in every primary color were equally divided into 17 stages, including 0 and 255, and thus the tristimulus values of 4913 colors at each display were measures. Size and shape of color gamuts varied with the luminance, sampling distribution and color difference of LCD and CRT will be discussed. The higher the value of Y, the smaller the area of the color gamut, no matter which display type performed. The area of the color gamut of LCD is smaller than that of CRT in most levels of luminance. This paper discovered that some special patterns exist in color gamut diagrams. Finally, relationships among patterns have been clarified for characterizing the color gamuts of displays., Presented at Display Technologies III, International Optoelectronics Symposium, Taipei, Taiwan, 26-27 Jul 2000. Pub. in Proceedings of SPIE, v4079 p271-276, 2000. ISSN 0277-786X. This article is from ADA398270 Display Technologies III Held in Taipei, Taiwan on 26-27 July 2000

Published
2000

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