• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권10호
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• pp.4930-4951
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• 2018

The deep learning based speech enhancement has shown considerable success. However, it still suffers performance degradation under mismatch conditions. In this paper, an adaptation method is proposed to improve the performance under noise mismatch conditions. Firstly, we advise a noise aware training by supplying identity vectors (i-vectors) as parallel input features to adapt deep neural network (DNN) acoustic models with the target noise. Secondly, given a small amount of adaptation data, the noise-dependent DNN is obtained by using $L_2$ regularization from a noise-independent DNN, and forcing the estimated masks to be close to the unadapted condition. Finally, experiments were carried out on different noise and SNR conditions, and the proposed method has achieved significantly 0.1%-9.6% benefits of STOI, and provided consistent improvement in PESQ and segSNR against the baseline systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.522-529
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• 2005

The commercial service of KTX from April 1st 2004 has realized that whole country has shrunk into half-day life zone and it opened the times of speed. However, some technical problems unexpected before service have been raised and, among them, the noise generation at train passing was claimed by the residents living nearby the track and it is often publicized by the broadcastings and newspapers. In case where the residential area is close to the track, the installation of noise barrier at trackside is the general measures for noise reduction on bridge section and earthwork section. In case of KTX project, such measures were actually taken without any exception; however, the noise level is still high. In this study, analysis for the reason of higher noise level in spite of which the noise barriers are being installed was carried out, the sample of insulation material effective for noise barrier was manufactured and the performance of the insulation material was evaluated to verify its effectiveness

• 대한기계학회논문집B
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• 제27권3호
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• pp.286-293
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• 2003

The unsteady flow characteristics and associated blade tonal noise of a cross-flow fan are predicted by computational methods. The incompressible Navier-Stokes equations are time-accurately solved for obtaining the pressure fluctuations between the rotating blades and the stabilizer. and the sound pressure is predicted using Curie's equation. The discrete noise characteristics of three impellers with a uniform and two random pitch (type-A and -B) blades are compared by their SPL (Sound Pressure Level) spectra. and the frequency modulation characteristics of the BPF (Blade Passing Frequency) noise are discussed. Besides. a mathematical model is proposed for the prediction of discrete blade tonal noise and is validated with available experimental data. The fan performance is also compared with experimental data. indicating that the random pitch effect does not significantly alter the performance characteristics at ${\phi}$ 〉 0.4

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.361-364
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• 2011

In this paper, This work demonstrates a experimental evaluation for vehicle road noise NVH performance from the component-level NVH measurements of Tire. The power unit noise from tire emitted by cars has been reduced. It has been found that tire noise dominates noise produced by the power train when vehicles are driven at high constant speed. Therefore tire pattern noise is affected by pattern and vehicle and transmission loss. Tire noise mechanism is generated by several mechanisms. The sound of tire can propagate either through the air or through the structure of vehicle. Pattern noise is the result of pressure variations through the air to the interior side of vehicle. Especially, smooth asphalt, the periodicity of tread design, groove depth is important factor, which have an influence on the reduction of tire pattern noise.

• Journal of information and communication convergence engineering
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• 제9권1호
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• pp.59-63
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• 2011

Conventional noise reduction filtering schemes realize limited improvements of the peak signal-to-noise ratio (PSNR) in the low-level noisy images. The flatness degree and the edge information are effectively used to estimate the noise volume. We propose a noise estimator for reducing noise in the AWGN (additive white gaussian noise) corrupted images using three intermediate image maps (FGM(flatness gray map), FIM(flatness index map), NEM(noise estimate map)). The proposed noise estimator is fed into the conventional noise reduction filters as a pre-processor. The performance of noise reduction is tested in the various AWGN corrupted images.

• Structural Engineering and Mechanics
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• 제72권4호
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• pp.421-432
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• 2019

In high-speed railway (HSR) system, the structure-borne noise inside viaduct at low frequency has been extensively investigated for its mitigation as a research hotspot owing to its harm to the nearby residents. This study proposed a novel acoustic optimization method for declining the structure-borne noise in viaduct-like structures by separating the acoustic contribution of each structural component in the measured acoustic field. The structural vibration and related acoustic sourcing, propagation, and radiation characteristics for the viaduct box girder under passing vehicle loading are studied by incorporating Finite Element Method (FEM) with Modal Acoustic Vector (MAV) analysis. Based on the Modal Acoustic Transfer Vector (MATV), the structural vibration mode that contributes maximum to the structure-borne noise shall be hereinafter filtered for the acoustic radiation. With vibration mode shapes, the locations of maximum amplitudes for being ribbed to mitigate the structure-borne noise are then obtained, and the structure-borne noise mitigation performance shall be eventually analyzed regarding to the ribbing conduction. The results demonstrate that the structural vibration and structure-borne noise of the viaduct box girder mainly occupy both in the range within 100 Hz, and the dominant frequency bands both are [31.5, 80] Hz. The peak frequency for the structure-borne noise of the viaduct box girder is mainly caused by $16^{th}$ and $62^{th}$ vibration modes; these two mode shapes mainly reflect the local vibration of the wing plate and top plate. By introducing web plate at the maximum amplitude of main mode shapes that contribute most to the acoustic modal contribution factors, the acoustic pressure peaks at the field-testing points are hereinafter obviously declined, this implies that the structure-borne noise mitigation performance is relatively promising for the viaduct.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.407-412
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• 2000

Response surface method is employed in optimizing the acoustic performance of automotive engine-cooling axial fans. The effects of modifications in blade geometry on noise reduction are investigated. Taking the far-field noise level as the objective, a quadratic response surface is constructed utilizing D-Optimality condition as the candidate-points selection criteria. It is shown that the quadratic model exhibits an excellent fitting capability resulting in the blade design with low far-field noise level.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.534-537
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• 2011

This Paper present prediction Vehicle Interior Noise using ATF(Acoustic Transfer Function) and engine radiated sound power. This is useful tool to qualifying the effectiveness of Air-borne noise Path. Furthermore This method provide acoustic package performance of the vehicle and able to prepare frequency band to same segment or benchmarking vehicle.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2004년도 유체기계 연구개발 발표회 논문집
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• pp.509-513
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• 2004

There are a lot of efforts to improve noise and vibration in compressor. It had depended on experiments to reduce the annoying noise and vibration raised by costumer complaints until the twentieth century. But a trend of noise and vibration research changed tremendously by simulation techniques. Simulation techniques are also applied to fields on acoustic and valve dynamics etc, to validate a experiment and improve the performance of various fields in noise and vibration.

• 한국음향학회지
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• 제42권3호
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• pp.181-188
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• 2023

일반적인 거주 공간에서 창호는 외부소음에 직접적으로 노출된다. 외부소음을 가장 효과적으로 저감할 수 있는 방법은 내부가 아닌 외부에서 바로 소음을 차단하는 방법이다. 태양 빛 차단을 위한 외부 블라인드는 다양하게 제품화되어 있지만, 우리나라에서는 아직 적극적으로 활용되지 못하고 있다. 앞선 연구에서는 차광용으로 제작된 외부 전동블라인드의 차음성능을 검증하기 위해 공인 실험실에서 실험하였다. 그 결과 일반창호 저감 성능 대비 6 dBA의 추가 차음성능을 검증하였다. 이 연구에서는 외부 전동블라인드의 차음성능을 실제 거주 공간 창호에 실증 적용하여 저감성능을 확인하고자 하였으며, 효과적인 소음저감 성능 추가확보를 위해 개선방안을 모색하고자 하였다. 실험결과, 외부 전동블라인드 자체의 저감 성능은 기본 창호 대비 1 dBA ~ 3 dBA 수준으로 미미했다. 하지만 블라인드 슬릿 사이의 틈새 충진을 통해 2 dBA 수준의 추가 저감성능을 확인하였다.