Showing papers by "Sang-Kwon Lee published in 2018"
TL;DR: In this paper, an adaptive filter with an optimal weight vector for the active control of a quasi-stationary narrowband sinusoidal signal was proposed to reduce the engine noise inside the cabin of a car.
Abstract: This paper presents a novel active noise cancellation (ANC) method to reduce the engine noise inside the cabin of a car. During the last three decades, many methods have been developed for the active control of a quasi-stationary narrowband sinusoidal signal. However, since the interior noise signal is non-stationary with a fast frequency variation when the car accelerates rapidly, these methods cannot stably reduce the interior noise. The proposed method can reduce the interior noise stably even if the speed of the car is changed quickly. The method uses an adaptive filter with an optimal weight vector for the active control of such an engine noise. The method of determining the optimal weight vector of an adaptive filter is demonstrated. In order to validate the advantages of the proposed method, a conventional method and the proposed method are simulated with three synthesized signals. Finally, the proposed method is applied to the cancellation of booming noise in a sport utility vehicle. We demonstrate that the performance of the ANC system with the proposed algorithm is excellent for the attenuation of engine noise inside the cabin of a car.
35 citations
TL;DR: This article presents the new detection process of tooth faults in a gearbox system based on the empirical mode decomposition algorithm which adaptively decomposes the signal into a set of intrinsic mode functions and the cyclostationarity process which identifies the hidden periodicity clearly in bi-frequency domain.
Abstract: In the previous work, the cyclostationarity process, which is one of signal processing methods, has been used in health monitoring of the rotating machinery because of the superior detecting proper...
16 citations
TL;DR: In this paper, Dong-Un Yun et al. applied time-frequency masking to the diesel engine sound signals and calculated the modulation degree of those signals by a correlation test, and the DSQI was successfully applied to the quantification of knocking noise of diesel engines.
Abstract: The present study focused on knocking noises of internal combustion engines. It was shown that the quantification of knocking noise can be calculated by considering time-frequency masking. The knocking noises were synthesized from the characteristics of diesel engine sounds. The subjective rating of these sounds was performed by a jury test. For the objective evaluation, time-frequency masking is applied to the knocking sound signals, and the modulation degree of those signals was calculated. By a correlation test, the diesel sound quality index (DSQI) was developed. The DSQI was successfully applied to the quantification of knocking noise of diesel engines. Dong-Un Yun et al. ; Evaluation of Sound Quality of a Diesel Engine with Considering Masking Effect 650 ┃ Trans. Korean Soc. Noise Vib. Eng., 28(6) : 649~654, 2018 른 시간에 영향을 미치는 시간 마스킹이 존재하고 있 으며 두 마스킹은 동시에 영향을 미친다. 그러나 CKI 기술은 동시에 영향을 미치는 것을 고려한 것이 아니라 두 마스킹 효과 중에 가장 효과가 큰 것을 사용하였다. 특히 노킹소음은 진폭변조 및 주파수 변조가 동시에 발 생함으로 두 마스킹 효과를 동시에 고려해야 한다. 이 연구에서는 엔진 폭발에 기인한 저주파의 하모닉 성분의 주파수 마스킹효과와 진폭변조특성으로 발생하 는 최대 음압 점에 대한 시간 마스킹효과를 고려하여 연소소음 정량화에 적용하고자 한다. 연구방법은 엔진 에서 발생하는 노킹소음을 신호처리 기술을 통하여 모 델링 후 합성음을 제작한다. 여기에 마스킹효과를 고 려하여 진폭변조 정도를 계산한다. 다음 단계로 합성 음에 대한 청음평가 결과를 시행하여 변조도와 상관도 비교를 하여 알고리듬의 유효함을 검증한다. 이 결과 를 실제 엔진에 적용하기 위하여 엔진실험을 실행하였 으며, 엔진의 실험 조건은 디젤 연소 노킹음이 가장 많 이 발생하는 정속 조건과, 가속조건에서 실시하였다. 측정된 엔진 소음에 이 연구에서 개발된 시간-주파수 마스킹 기술을 적용하고 청음평가와의 상관성을 통하 여 마스킹 효과를 검증하였다. 검증된 알고리듬을 활 용하여 디젤엔진음질인덱스를 개발하였다.
1 citations