• 한국항행학회논문지
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• 제7권1호
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• pp.30-37
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• 2003

본 논문에서는 Middleton이 제안한 A급 임펄스성 잡음이 존재하는 실내 무선 환경에서 MC (Multi-Carrier) CDMA 시스템의 BER (Bit Error Rate) 성능을 분석하였고, 임펄스성이 약한 환경에서부터 강한 환경까지 성능을 평가하였다. 그리고 임펄스성 잡음에 대한 보상 방법으로 Turbo 부호기를 사용하여 성능 개선 정도를 평가하였다. 성능 해석 결과, 임펄스성 잡음 환경에서는 강력한 성능 개선 기법이 시스템에 반드시 필요함을 알 수 있었다. 그리고 임펄스성 잡음 환경에서 터보 부호를 적용하면 BER면에서 약 $10^{-2}$정도 개선됨을 알 수 있었고, AWGN 환경에 근접할수록 터보 부호에 의한 성능 개선 효과가 뚜렷이 나타남을 알 수 있었다.

• 한국인터넷방송통신학회논문지
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• 제10권6호
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• pp.99-105
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• 2010

통신 시스템의 성능을 유도하기위하여 가장 많이 가정하는 잡음의 모델은 부가성 백색 잡음이다. 그러나 실제 통신 시스템을 사용하는 환경에서는 임펄시브 잡음이 더욱 현실적인 모델이기 때문에 최근에는 임펄시브 잡음 하에서의 통신 시스템의 성능을 분석하는 연구가 증가하고 있다. 따라서 본 논문에서는 최근에 집중적인 연구 주제가 되고 있는 협동다이버시티 시스템을 대상으로 하여 임펄시브 잡음하에서 시스템의 성능을 유도하였다. 특히 릴레이 방식으로 복조후 전송방식과 증폭후 전송방식을 사용하였을 때의 성능을 해석적으로 유도하고 비교하였다. 연구결과 레일레이 페이딩을 받는 무선 채널에서, 임펄시브 잡음의 평균 임펄스의 수가 감소할수록 잡음의 임펄시브 성분이 증가하고, 그 결과 신호 대 잡음비(SNR)가 큰 영역에서 시스템의 성능은 열화되었다. 그리고 동일한 조건에서 복조후 전송 릴레이를 채택한 협동 다이버시티 시스템이 증폭후 전송방식을 채택하였을 때보다 우수한 성능을 나타내었다.

• 한국안전학회지
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• 제12권4호
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• pp.3-8
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• 1997

This paper shows a performance estimation of windowing a single tone with added Gaussian noise and uniform noise. Signal-to-noise ratio can be determined by the ratio of the output noisy signal variance to the input noisy signal variance of a window. Standard deviation of noise is reduced by windowing Signal-to-noise ratio of the noisy signal is reduced by the windowing operation. Thus, performance of window function can be determined by this filtering operation that improved the signal-to-noise ratio.

• 전기학회논문지P
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• 제63권3호
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• pp.157-162
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• 2014

The active noise control(ANC) method for noise problems solution generally uses filtered-X LMS algorithms. However, Filtered-X LMS algorithms were mainly used but these had a limitation that had to measure a transfer function of secondary noise path. However, newly proposed correlation-LMS algorithms have slightly much calculation and are minutely behind performance, these have a advantage not in measuring transfer function onerously so that we can easily adapt these in real time. Thus Co-LMS algorithm was developed to improve the real-time implementation performance under the variable input noise such as road noise environment. In this paper, the performance of the Co-LMS is presented in comparison with that of the Filtered-X LMS algorithm. Simulation results show that active noise control using Co-LMS have slightly much calculation and are minutely behind performance, these have a advantage not in measuring transfer function onerously so that we can easily adapt these in real time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2011년도 춘계학술대회 논문집
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• pp.735-741
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• 2011

In the early phase of vehicle development, CAE is conducted as tool for vehicle performance assessment. To maintain acceptable road noise performance, solution for reduced vehicle sensitivity is required. Chassis interface dynamic stiffness characteristics are key component to isolating vibration and noise of road from the vehicle interior. This research provide how to set up the optimized dynamic characteristics under noise effect through DFSS study. CAE-based DOE is performed to build prediction math model, CMS process involves DOE to achieve very fast run times while giving results very comparable. Minimized $95^{th}$ percentile of performance distribution is applied to minimize vehicle sensitivity and road noise levels variation during the optimization process. Finally, the results of optimization were reviewed for performance and robustness.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1125-1128
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• 2007

In order to improve the acoustic performance of a noise barrier without increasing its height, various type of acoustic devices are suggested but, there is no proper method to estimate the performance in Korea. For this, an outdoor test facility was established in Expressway and Transportation Technology Institute(ETTI) of Korea Expressway Corporation for testing the acoustical performance of noise reducing devices installed on the top of a noise barrier. Noise measurements before and after installation of the noise reducing devices were carried out by using sound pressure level for long distance range from the barrier, from 10m to 40m. For considering the directivity effects of noise reducing devices, multivariate regression analysis was attempted.

• 한국정보통신학회논문지
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• 제15권4호
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• pp.897-904
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• 2011

본 논문에서는 CMOS 능동 인덕터를 이용하여 1.8GHz PCS 대역과 2.4GHz WLAN 대역에서 동조가 가능한 저잡음 증폭기의 새로운 회로구조를 제안하였다. CMOS 능동 인덕터 부하를 이용하는 저잡음 증폭기의 높은 잡음지수를 줄이기 위한 회로구조와 잡음지수를 더욱 감소시키기 위한 잡음상쇄기법을 적용하고 해석하였다. 이 동조가능 저잡음 증폭기를 $0.18{\mu}m$ CMOS 공정기술로 시뮬레이션을 수행한 결과는 잡음성능이 약 3.4dB 향상된 것을 보여주며, 이는 주로 제안된 새로운 회로구조에 기인한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 C
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• pp.1784-1786
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• 1996

It is necessary to eliminate the broad band noise which frequency is in a few kHz to MHz in the AC line to supply the power to electrical and electronic control equipments. Because this kind of noise could damage the device or could be a source of malfunction, many devices like a filter and surge suppressor are developed to cut off the noise. But those device could not disconnected from the power line, so it remain some problem and on be used in limited area, In this paper, we present performance test results NCT(noise Cut Transformer) with excellent performance for reducing the high frequency noise and surge existing in the power line.

• 한국소음진동공학회논문집
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• 제14권10호
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• pp.939-944
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• 2004

The numerical methods including the performance analysis and the noise prediction of the centrifugal compressor impeller are coupled with the optimization design skill, which consists of response surface method, statistical approach, and genetic algorithm. The flow-field Inside of a centrifugal compressor is obtained numerically by solving Wavier-Stokes equations. and then the propagating noise is estimated from the distributed surface pressure by using Ffowcs Williams-Hawkings formulation. The quadratic response surface model with D-optimal 3-level factorial experimental design points is constructed to optimize the impeller geometry for the advanced centrifugal compressor. The statistical analysis shows that the quadratic model exhibits a reasonable fitting quality resulting in the impeller blade design with high performance and low far-field noise level. The influences of selected design variables, objective functions, and constraints on the impeller performance and the impeller noise are also examined as a result of the optimization process.

• 한국소음진동공학회논문집
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• 제13권2호
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• pp.144-150
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• 2003

Pleasantness or quietness becomes one of the most important factors for residential and office building designs recently. Especially for apartments, the noise generated by falling objects becomes a sensitive issue these days. To overcome the problem of the impact noise in apartments, the floor design has been changed. To reduce the transmissibility of the noise. composite floor structures ate devised and implemented for the construction of apartments. In this paper. the noise reduction) performance of a composite floor plate with holes is analyzed. Computational models for the structures are developed and its Performance is evaluated by using the finite element method. The results show that the noise can be significantly reduced with the multi-layer composite floor plates with holes.