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213 results on '"Chang, Yuan-Jen"'

10. The Optimization of a Model for Predicting the Remaining Useful Life and Fault Diagnosis of Landing Gear.

Author

Chang, Yuan-Jen, Hsu, He-Kai, Hsu, Tzu-Hsuan, Chen, Tsung-Ti, and Hwang, Po-Wen

Subjects
REMAINING useful life, LANDING gear, FAULT diagnosis, FLIGHT recorders, KRIGING, MOVING average process, BOX-Jenkins forecasting
Abstract

With the development of next-generation airplanes, the complexity of equipment has increased rapidly, and traditional maintenance solutions have become cost-intensive and time-consuming. Therefore, the main objective of this study is to adopt predictive maintenance techniques in daily maintenance in order to reduce manpower, time, and the cost of maintenance, as well as increase aircraft availability. The landing gear system is an important component of an aircraft. Wear and tear on the parts of the landing gear may result in oscillations during take-off and landing rolling and even affect the safety of the fuselage in severe cases. This study acquires vibration signals from the flight data recorder and uses prognostic and health management technology to evaluate the health indicators (HI) of the landing gear. The HI is used to monitor the health status and predict the remaining useful life (RUL). The RUL prediction model is optimized through hyperparameter optimization and using the random search algorithm. Using the RUL prediction model, the health status of the landing gear can be monitored, and adaptive maintenance can be carried out. After the optimization of the RUL prediction model, the root-mean-square errors of the three RUL prediction models, that is, the autoregressive model, Gaussian process regression, and the autoregressive integrated moving average, decreased by 45.69%, 55.18%, and 1.34%, respectively. In addition, the XGBoost algorithm is applied to simultaneously output multiple fault types. This model provides a more realistic representation of the actual conditions under which an aircraft might exhibit multiple faults. With an optimal fault diagnosis model, when an anomaly is detected in the landing gear, the faulty part can be quickly diagnosed, thus enabling faster and more adaptive maintenance. The optimized multi-fault diagnosis model proposed in this study achieves average accuracy, a precision rate, a recall rate, and an F1 score of more than 96.8% for twenty types of faults. [ABSTRACT FROM AUTHOR]

Published
2023
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19. Accurate Analysis of IEEE 802.15.4 Slotted CSMA/CA over a Real-Time Wireless Sensor Network

Author

Huang, Wen-Tzeng, Lin, Jing-Ting, Chen, Chin-Hsing, Chang, Yuan-Jen, Chen, You-Yin, Akan, Ozgur, Series editor, Bellavista, Paolo, Series editor, Cao, Jiannong, Series editor, Dressler, Falko, Series editor, Ferrari, Domenico, Series editor, Gerla, Mario, Series editor, Kobayashi, Hisashi, Series editor, Palazzo, Sergio, Series editor, Sahni, Sartaj, Series editor, Shen, Xuemin (Sherman), Series editor, Stan, Mircea, Series editor, Xiaohua, Jia, Series editor, Zomaya, Albert, Series editor, Coulson, Geoffrey, Series editor, Hailes, Stephen, editor, Sicari, Sabrina, editor, and Roussos, George, editor

Published
2010
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36. Holographic interferometry study of spatially periodic heat transfer in a channel with ribs detached from one wall

Author

Liou, Tong-Miin, Wang, Wen-Bin, and Chang, Yuan-Jen

Subjects
Heat -- Conduction, Holographic interferometry -- Research, Engineering and manufacturing industries, Science and technology
Abstract

The holographic interferometry study helps evaluate turbulent heat transfer and fiction in a fully developed periodic region of a 4:1 aspect ratio rectangular duct. The ducts have square ribs at a little distance away from the walls. The results reveal that the critical clearance ratio exists for these ducts. The clearance ratio controls the process of heat transfer augmentation.

Published
1995

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