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김영달,장석구 한국소음진동공학회 2000 소음 진동 Vol.10 No.6
Active noise control is an approach to reduce the noise by utilizing a secondary noise source that destructively interferes with the unwanted noise. In general, active noise control systems rely on multiple sensors to measure the unwanted noise field and the effect of the cancellation. This paper develops an approach that utilizes a single sensor. The noise field is modeled as a stochastic process, and an adaptive algorithm is used to adaptively estimate the parameters of the process. Based on these parameter estimates, a canceling signal is generated. Oppenheim assumed that transfer function characteristics from the canceling source to the error sensor is only a propagation delay. This paper proposes a modified Oppenheim algorithm by considering transfer characteristics of speaker-path-sensor This transfer characteristics is adaptively cancelled by the proposed adaptive modeling technique. Feasibility of the proposed method is proved by computer simulations with artificially generated random noises and sine wave noise. The details of the proposed architecture. and theoretical simulation of the noise cancellation system for three dimension enclosure are presented in the Paper.
김영달,전시식,차동욱 대한전기학회 2022 전기학회논문지 Vol.71 No.1
Partial discharge diagnosis is being carried out to prevent failure of ground switch of distribution facilities. However, the reliability of partial discharge diagnosis is insufficient because the results are different depending on how the experts classify the partial discharge and noise signals. Therefore, in this paper, a method to automatically classify partial discharge and noise signals was studied in order to improve the reliability of the partial discharge diagnosis results of ground switch. Partial discharge and noise signal are obtained through the High Frequency Current Transformer(HFCT). And the features were extracted based on the pulse shape analysis, the standard deviation and gravity center of signal. The features are used as input to neural networks and learned using back-propagation. In addition, the structure of neural networks was optimized through genetic algorithm.
김영달,이민명,정창경,Kim, Yeong-Dal,Lee, Min-Myeong,Jeong, Chang-Gyeong 대한전기학회 2000 전기학회논문지 D Vol.52 No.1
Active noise control is an approach to noise reduction in which a secondary noise source that destructively interferes with the unwanted noise. In general, active noise control systems rely on multiple sensors to measure the unwanted noise field and the effect of the cancellation. This paper develops an approach that utilizes a single sensor. The noise field is modeled as a stochastic process, and a time-adaptive algorithm is used to adaptively estimate the parameters of the process. Based on these parameter estimates, a canceling signal is generated. Opppenheim model assumed that transfer function characteristics from the canceling source to the error sensor is only propagation delay. But this paper proposes a modified Oppenheim model by considering transfer characteristics of acoustic device and noise path. This transfer characteristics is adaptively cancelled by adaptive model. This is proved by computer simulation with artifically generated random noise and sine wave noise. The details of the proposed architecture, and theoretical simulation and experimental results of the noise cancellation system for three dimension enclosure are presented in the paper.
김영달 三陟大學校 1994 論文集 Vol.27 No.-
Ground vibration is the most serious of the factors affecting the surface constructs in an urban blasting. To set up a control measure for ground vibration, I took into account the open-air blastings conducted by the Samchok factory of Dongyang Cement Co. Ltd. The damage limit of blasting vibration was fixed on the peak particle velocity 5cm/sec, which was proposed by Langefors and USBM, while the generalized form V=KL??d ?? was used for the blasting vinbration formula. The results are as follows. 1) The constant K, which is determined by the ground condition, was found to be 38.95 in the vertical direction. 2) The index m was found to be 0.5, which is determined by the quanity of the charging gun-powder. 3) The distance diminution index n was found to be 1.54, which is determined by the distance between the blasting point and the measuring point.