• 한국컴퓨터산업학회논문지
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• 제5권2호
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• pp.269-274
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• 2004

기존 음성 인식의 실세계 적용에서 큰 문제점은 잡음이다. 본 논문에서는 잡음이 섞인 음성 신호로부터 잡음 성분을 분리해 내는 방법을 제안한다. 이 방법은 잡음이 섞인 음성 신호에 독립성분분석(ICA:Independent Component Analysis)을 사용한 암묵신호 분리(blind source separation)를 적용하여 잡음 성분을 제거하게 된다. 잡음이 혼합된 음성 신호에 독립성분분석을 전처리(preprocessing) 과정에 이용함으로써 인식성능을 향상시킬 수 있다. 깨끗한 음성 신호에 음악과 거리잡음을 섞었을 경우 인식률이 잡음 없는 음성의 인식률보다 각각 최대 14.98%, 13.78%까지 저하되었다. 그러나 독립성분분석으로 복원된 음성의 경우 잡음 없는 음성의 인식률 수준(각각 97.39%, 96.49%)으로 나타났으며, 독립성분분석을 이용한 음성의 잡음 제거가 인식률 향상에 좋은 결과를 가져옴을 확인 할 수 있다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.404-406
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• 2014

The NDIF method is developed for eigenvalue analysis of arbitrarily shaped two-dimensional acoustic cavity with a mixed boundary, which consists of rigid-wall and open boundaries. The NDIF method, which was developed by the author in 2000, has the feature that it yields highly accurate eigenvalues compared with other analytical methods or numerical methods (FEM and BEM). The validity of the proposed method is shown in a case study, which indicate that eigenvalues obtained by the proposed method are more accurate compared to the exact method or FEM(ANSYS).

• 한국게임학회 논문지
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• 제11권6호
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• pp.3-11
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• 2011

디지털미디어의 사운드는 인간의 감각을 자극하여 커뮤니케이션을 수행한다. 소리 자극은 생리적 흥분을 가져오고 반응에 민감한 상태로 각성시키는데, 이는 심장박동, 혈압, 뇌파신호로 나타난다. 본 논문에서는 이완효과가 있는 백색잡음을 혼합한 게임음악과 백색잡음이 섞이지 않은 게임음악을 듣는 게임 플레이어의 뇌파변화를 검사했다. 실험은 두 그룹으로 나누어 진행되었으며 A 그룹은 백색잡음이 섞인 게임음악을, B 그룹은 백색잡음이 섞이지 않은 게임음악을 들으며 게임을 플레이했다. 두 그룹의 전전두엽 뇌파 변화를 측정한 결과 좌뇌에서는 백색 잡음의 이완효과가 나타났으며, 우뇌의 경우는 기대치에 미치지 못했다. 본 연구는 백색잡음의 이완효과를 이용한 기능성 심리치료 게임을 개발하기 위한 기본 연구가 될 것이다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.255-257
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• 2018

최근 다양한 분야에서 영상매체의 사용 빈도가 증가함에 따라 신호처리의 중요성이 높아지고 있다. 하지만 송수신 과정에서 많은 종류의 잡음이 발생하며 신호의 정보에 영향을 미치고 있으며, 이러한 이유로 잡음 제거를 전처리 과정으로서 필수적으로 행한다. 본 논문에서는 임펄스 잡음과 AWGN이 혼합된 잡음을 제거하기 위한 알고리즘을 제안하였다. 제안한 알고리즘은 효율적인 잡음 제거를 위해 잡음 판단과 화소 변화를 통해 영상을 복원하였으며, 기존 방법과 달리 두 잡음의 영향을 모두 최소화하여 잡음을 제거하는 모습을 보였다. 시뮬레이션 결과 우수한 잡음제거 특성을 나타내었으며, 객관적인 판단을 위해 PSNR 등을 이용하여 비교 및 분석하였다.

• 대한인간공학회지
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• 제15권1호
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• pp.79-90
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• 1996

A research project was conducted to assess the levels of noise exposed to "Noraebang" users and potential hazards to noise-induced hearing loss due to commercial Noraebang noise. A two-way, mixed-factors factorial design was employed for the experiment using independent variables of "noise source" (no- singer, 1-singer, and 2-singer conditions) and "music type" (Trot, Ballad, and Rock music) with 18 normal hearing subjects. Each singer group sang 5 popular songs of each music type in each signing condition, whereas background music was just played for the no-singer condition. For each music played/sung, equivalent continuous sound pressure levels and maximum sound pressure levels were measured for data analysis purposes. Pure-tone audiometry was applied for measuring subjects' hearing threshold levels before and after exposure to Noraebgang noise. The statistical analyses indicate that average continuous noise levels due to Noraebang leisure environment were very serious, especially when two people were singing (higher than 95 dBA). Furthermore, maximum noise levels often exceeded the OSHA's non-premissible 115 dBA level. Worse yet, hearing loss assessment implies that Noraebang facilities may pose a serious threat to noise-induced hearing loss, based on 6-8 dB loss at 125 Hz and 8 dB loss at 4000 Hz after about 1-hour Noraebang noise exposure.

• 항공우주시스템공학회지
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• 제7권1호
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• pp.8-18
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• 2013

Recently, the advanced condition monitoring methods such as the model-based method and the artificial intelligent method have been applied to maximize the availability as well as to minimize the maintenance cost of the aircraft gas turbines. Among them the non-linear GPA(Gas Path Analysis) method and the GA(Genetic Algorithms) have lots of advantages to diagnose the engines compared to other advanced condition monitoring methods such as the linear GPA, fuzzy logic and neural networks. Therefore this work applies both the non-linear GPA and the GA to diagnose AE3007 turbofan engine for an aircraft, and in case of having sensor noise and bias it is confirmed that the GA is better than the GPA through the comparison of two methods.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.446-454
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• 2011

The noise of the subway has become a social issue and includes very complex reasons. The friction between rail and train wheel is the most important reason of the noise. In this study, we developed MFI(Multi Fluid Injection) System which sprays the mixed fluid(water, anticorrosive and lubricant) on the rail when the train is approaching to reduce the friction. To verify the system's effect, we measured the internal and external noise of the running train. The measured and analyzed results show that MFI system reduce the noise of the running subway.

• 센서학회지
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• 제21권6호
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• pp.429-433
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• 2012

In this paper, we reduced the optical noise interference in a visible light communication system using two color LEDs. In the transmitter, the original and the inverted signals of the transmitted data modulated a red LED and a blue LED, respectively. In the receiver, a differential detector which is composed of two photodetectors and an optical red filter detected the mixed signal radiated from the two LEDs. In an environment that the optical noise from a fluorescent lamp exists, the signal-to-noise ratio in this system was improved by about 20dB compared to that in the conventional system which uses a single LED and a single photodetector.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 합동 추계학술대회 논문집 정보 및 제어부문
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• pp.562-564
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• 2002

Noise reduction and a simplification of a precision measurement system has been performed by changing analog output mode of a load cell into digital output mode. Usually, analog output signal of a few $\mu V$ from a load cell are amplified by amp and acquired by A/D converter. If the distance from a load cell to a DAS(Data Acquisition System) increases, more noise signals are mixed. So, a microprocessor has been integrated into a load cell so that the amplification and A/D conversion of output signals could be done in close proximity to the lode cell for the reduction in mixing of noise. Obtained data from the load cell like this manner are transferred to a computer with digital values(of TTL level). To simplify the configuration of a multi-channel DAS, RS-485 communication system has used for data transfer.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2006년도 하계종합학술대회
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• pp.895-896
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• 2006

This paper proposes a new method to measure the ECG signal from the driver. The ECG signal is often measured in the room. But it is mixed with many kinds of noise when we measure it during the vehicle moving. We classified noise occupied most many parts as the experimental among them. And we designed one suitable filter for each noise. It used ALE(Adaptive Line Enhancement) to remove the noise occurred to electromagnetic wave in vehicle. To remove the noise occurred to steering or vibration of vehicle, we used Wavelet transformation after ALE(preprocessing filter).