• Proceedings of the Acoustical Society of Korea Conference
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• 한국음향학회 2004년도 추계학술발표대회논문집 제23권 2호
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• pp.275-278
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• 2004

본 논문에서는 저 비트오율 압축 시 발생되는 신호 왜곡을 인간의 지각적 특성을 이용하여 음질을 개선하는 알고리즘을 제안한다. 저 비트오율 압축 과정에서 손실된 고주파 영역의 신호를 부가 정보를 사용하지 않고 손실되지 않은 영역의 정보를 사용하여 고주파 영역의 신호를 첨가함으로써 음질을 개선하였다. 비 손실 영역의 순음 및 비 순음 성분을 검출하여 손실영역에 해당 하모닉 성분을 청각 자극 에너지로 스케일 하여 새로운 신호를 첨가한다. 원 신호와 저 비트오율 압축으로 인해 왜곡된 신호, 그리고 본 논문의 알고리즘을 이용하여 개선된 신호를 신호 대 잡음 비를 측정하고 청감 테스트를 통해 음질 개선 효과를 확인하였다.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 한국정보기술응용학회 2005년도 6th 2005 International Conference on Computers, Communications and System
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• pp.335-338
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• 2005

In this paper, we propose a downlink power control scheme to apply in the unequal error protection multi-code CDMA mobile medicine system. The mobile medicine system contains (i) blood pressure and body temperature measurement value, (ii) ECG medical signals measured by the electrocardiogram device, (iii) mobile patient's history, (iv) G.729 audio signal, MPEG-4 CCD sensor video signal, and JPEG2000 medical image. By the help of the multi-code CDMA spread spectrum communication system with downlink power control scheme and unequal error protection strategy, it is possible to transmit mobile medicine media and meet the quality of service. Numerical analysis and simulation results show that the system is a well transmission platform in mobile medicine.

• Proceedings of the Korean Institute of Interior Design Conference
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• 한국실내디자인학회 2003년도 춘계학술발표대회 논문집
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• pp.35-38
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• 2003

According to developing digital media, the delivery and the collection of information are changing with a variety of ways. Especially, digital, as it is, is easy for its sound, video and letter to be mixed. Therefore, media character, Audio-Visual will appear in total. Hypertext must be a basic form in the traveling way of media information which includes such digital Quality in originality. Taking advantage of digital media trait of hypertext , most users can make a research on a variety of studying method. On this thesis, a style of made-up hypertext is taking a part of recent digital culture, and I want to present a different method in research, using two hypertext skills, adventurous choice and joint origination

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 한국방송공학회 2000년도 정기총회 및 학술대회
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• pp.29-35
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• 2000

음성 데이터의 패킷 지터(jitter)가 심할수록 오디오 플레이어가 오디오 데이터를 자연스럽게 재생하지 못하기 때문에 사용자는 원래의 음성을 거의 알아들을 수 없게 된다. 이 문제점을 해결하기 위하여 오디오 수신자는 전송 받은 오디오 데이터를 바로 재생하지 않고 재생시간을 지연시키는 방법을 사용한다. 본 연구자의 조사에 의하면 이러한 재생시간을 지연하는 대표적인 지터 컨트롤 알고리즘으로 6가지 방식이 제안되고 있다. 그 중 세 가지는 NeVot, Vat, Open H.323 프로그램 등에 구현되어 실제로 사용되고 있다 본 논문에서는 이들 6가지의 모델의 지터 컨트롤 알고리즘의 특성을 알아보고 어느 알고리즘이 효율적인지 알아보기 위해 현재 인터넷의 성능을 파악하고 이를 기초로 제안된 6가지 알고리즘 중 어느 것이 가장 효율적인가를 파악하여 오디오의 음질을 개선하기 위한 방법을 제시하고자 한다.

• ETRI Journal
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• 제31권3호
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• pp.336-338
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• 2009

This letter proposes a complexity reduction method to speed up the noiseless decoding of a bit-sliced arithmetic coding (BSAC) decoder. This scheme fully utilizes the group of consecutive arithmetic-coded symbols known as the decoding band and the significance tree structure sorted in order of significance at every decoding band. With the same audio quality, the proposed method reduces the number of calculations that are performed during the noiseless decoding in BSAC to about 22% of the amount of calculations with the conventional full-search method.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2003년도 하계학술대회
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• pp.234-239
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• 2003

디지털방송, DAB 등과 같은 디지털 오디오 방송 서비스를 위한 디지털 시스템을 설계하기 위해서는 오디오 음질을 평가하기 위한 방법이 필수적이다. 기존의 방식은 인간의 귀를 이용한 주관적 방식을 이용함으로서 많은 시간과 비용을 들이게 되며, 음질평가를 하는 사람의 주관적 의견에 많이 좌우하게 된다. 그러나 최근 ITV-R에서는 오디오 음질의 객관적 평가를 위한 BS.1387(PEAQ)를 제안함으로 많은 시간과 비용을 절감하고 신뢰할 수 있는 결과를 얻게 되었다. PEAQ는 인간의 귀에서의 신호의 처리과정과 인식과정을 심리음향모델과 인식모델로 분리하여 구성함으로써 주관적 평가의 SDG(Subjective Difference Grade)에 대응하는 ODG(Objective Difference Grade)를 구하게 된다. 본 논문에서는 이러한 PEAQ의 심리음향 모델과 인식 모델을 원리와 과정을 평가 분석하였다.

• Proceedings of the IEEK Conference
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• 대한전자공학회 2003년도 컴퓨터소사이어티 추계학술대회논문집
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• pp.7-10
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• 2003

In this paper, we present a new echo kernel, which is a modification of polar echo kernel. to improve the detection performance and robustness against attacks. Polar echo kernel may take advantage of large detection margin from the polarity of inserted echo signal, but its poor frequency response in low frequency band degrades sound quality. To solve this problem, we applied bipolar echo pulses to the polar echo kernel. Using the proposed echo kernel the distributions of autocepstrum peaks fur data ‘0’ and ‘1’ are located more distant and improvement of detection performance is achieved. It also makes the low frequency band flat so that the timbre difference in the polar echo kernel can be removed to reproduce the imperceptible sound qualify. Informal listening tests as well as robustness test against attacks were performed to evaluate the proposed echo kernel. Experimental results demonstrated the superiority of the proposed echo kernel to both conventional unipolar and polar echo kernels

• Proceedings of the IEEK Conference
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2467-2470
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• 2003

This paper presents a new structure of MPEG-4 AAC encoder. The proposed encoder directly shapes quantization noise distribution according to the energy distribution curve and thereafter performs adjustment of the offset level of the noise distribution to meet the given bit rate. The direct noise shaping and the bit rate matching scheme of the proposed encoder algorithm significantly alleviate the problem of conventional encoder's processing burden related with the employment of the precise psychoacoustic model and iteration intensive quantizer. The encoder algorithm is implemented on ARM processor with fixed-feint arithmetic operations. The audio quality of the implemented system is observed comparable to those of commercially available encoders, white the complexity of the implementation is drastically reduced in comparison to the conventional encoder systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.183-188
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• 2003

This study is to make the fundamentals of sound quality evaluation in regard of acoustical characteristics of passenger compartment. The deviation of frequency response function level within audible frequency is evaluated at receiving point in the research of room acoustics. In this study, frequency response function is the one between speaker and driver's ear positions. The positions of driver and audio speakers are optimized by analysis of acoustic mode of acoustic cavity. The main reflection planes are determined by analysis sound ray path diffused at optimized speaker positions. Finally, designer selects acoustical material by analysis of absorption effect of acoustical materials on the main reflection planes in order to avoid to distortion and fluctuation of frequency response function..

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2003년도 춘계학술대회 논문집 기술교육전문연구회
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• pp.96-102
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• 2003

Today, stage technology is developing highly by application of digital computer. Performance is composed of audio/video and acoustic technology takes very important position in field of stage technology. Generally speaking, four factors of sound are loudness, pitch, sound timbre and duration. Loudness depends on sound pressure level, yet partly related with spectrum and dulation. Pitch depends mainly on frequence and have a relation with sound pressure and duration. sound timbre depends strongly on spectrum and have a relation with frequence. In this paper, I designed a multi-microphone system which can used in broadcasting and performance stage with vicboss 200MHz-VHF wireless microphone and vicboss 900MHz-VHF wireless microphone. I also studied about multi-microphone which can use conveniently in the super play that needs many microphones. If this multi-microphone is prodused, we could expect better sound quality and a big progress in stereo recording technology.