• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.178-183
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• 1995

본 연구에서는 플랜트 잡음이 강한 음향 환경에서 기존의 인버스 필터링 방법에 적용 선형 증진기를 부착하여 부가경로 전달함수의 온라인 모델링과 주소음원에 대한 제어 시뮬레이션을 수행하여 다음과 같은 결과를 얻었다. 첫째로, 신호대 잡음비가 낮은 음향 환경에서 적응 선형 증진기를 이용하여 플랜트 잡음을 제거함으로써 부가경로 전달함수의 온라인 모델링을 수행할 수 있었다. 둘째로, 실제의 부가경로 전달함수가 변한 상태에서 제안된 알고리즘을 이용하여 제어 시뮬레이션을 수행하여 주소음원에 대한 제어와 정확하게 새로운 부가경로 전달함수를 예측할 수 있었다. 향후 본 연구에서 제안된 알고리즘을 실시간 어셈블리화하여 능동 소음 제어 실험한 결과를 발표할 예정이다.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.3
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• pp.251-260
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• 2009

In this paper, we studied on an attenuation effect of automobile exhaust noise according to the direction of canceling speaker in ANC system. Automobile exhaust noise was recorded at 800 rpm, 3500 rpm and 5000 rpm of a diesel engine. Directions of canceling speaker can be set to $30^{\circ}$, $90^{\circ}$ and $150^{\circ}$ against the primary noise flow by acrylic ducts to be made for the experimentation. DSP board with TMS320C6416 chip of Texas Instrument Co. used to control the ANC system. The algorithm of this ANC system applied the Filtered-x-LMS algorithm that is modified to compensate for a property of DSP input signal and the secondary-path effect. As an experiment result, the direction of canceling speaker was proved to influence the reduction effect of noise. The $150^{\circ}$ duct in the attenuation effect of noise showed a better result than the $90^{\circ}$ or $30^{\circ}$ duct.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.127-130
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• 2004

다이나믹 스피커의 진동판과 보이스코일을 지지하는 댐퍼는 스피커 진동부에 복원력을 공급하는 탄성체로서만 고려되어 왔다. 즉, 음파발생 장치로서 스피커를 고려할 때, 음파발생부로서 진동판과 부가적 음파발생부로서 에지에 의한 영향만이 고려되어 왔다. 본 논문에서는 진동판과 에지를 제거한 후, 댐퍼와 보이스코일 만으로 진동하는 다이나믹 스피커를 제작하여 댐퍼에 의해 발생된 음파의 특성을 측정하였다. 다음으로 댐퍼를 개별적인 음원으로 가정하여 댐퍼에 의해 발생된 음파를 계산하여 측정치와 비교하였다. 결론적으로 댐퍼는 스피커 진동계 복원력을 제공하는 요소로저 만이 아닌 진동판 이외의 부가적인 음원이 됨을 확인할 수 있었다.

• The Journal of the Korea Contents Association
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• v.18 no.10
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• pp.267-278
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• 2018

The purpose of this study is to analyze how the vertical integration, which is the main characteristic of the domestic digital music market, appears in each period and how these phenomena affect the digital music market. As a result, we could find out that the domestic digital music market is a vertically integrated market centered on ISPs. There were a variety of subjects that led the digital music market from the early digital music in 2000s to the latest streaming market. However, ISP was the only subject that vertically integrated all aspects of content, distribution, and consumption through its subsidiaries and affiliated companies. A variety of combined services, supplementary services, and fare plans provided by using its platform and network have become mainstream services in the domestic digital market and have fixed the current transaction type in domestic market.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.04a
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• pp.161-164
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• 1995

실시간 ANC 이전에, 소음원으로부터 대상계를 거친 신호와 소음원신호가 오차계를 거친 신호를 측정함으로서 이론적인 한계성능을 파악하기 위한 지표를 제시하였다. 이 지표는 오차계를 통과한 신호를 입력으로, 대상계를 통과한 신호를 출력으로 하는 계의 선형화 정도를 나타내는 다중기여도함수와 흡사한 형태로 나타났다. 제한된 상황에서 ANC 성능을 최대화 하고자 할 때 이 지표는 레퍼런스와 부가음원의 위치 및 갯수 결정등 여러가지 파라메터 결정에 매우 유용하게 쓰일 수 있다고 생각된다.

• Digital Contents
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• no.7 s.122
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• pp.128-131
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• 2003

사람은 두 귀를 사용해 어떤 소리를 들었을 때, 그것이 3차원 공간상의 어느 지점과 방향으로부터 들려오는지 감지할 수 있다. 또한 그 음이 속한 음향적 환경(예를 들면 실내, 야외, 강당, 동굴 등)을 구분할 수 있다. '3D사운드'란 음원이 발생한 공간에 위치하지 않은 청취자가 음향을 들었을 때에 방향감, 거리감 및 공간감을 지각할 수 있도록 음향에 공간 정보를 부가한 음향을 말한다.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.189-192
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• 1999

수중소음체의 음원 특징을 해석하기 위해서는 배경잡음과 해면$\cdot$해저반사파의 영향이 적은 심해에서 측정하여 분석하여야 한다. 그러나 측정의 어려움으로 인공 수조에서 측정하여 수면과 수조벽에 의해 발생되는 반사파들을 제거하여 신호 고유의 특징을 해석한다 이러한 반사파들의 부가효과를 보상하여 수중소음체의 신호특징을 해석하기 위하여 정합필터배열처리(Matched Filter Array Process : MFAP)기법을 적용하고자 할 때 각 센서에 적용되는 정합필터는 처리시간의 문제로 인해 필터길이를 제한하여 구성되게 된다 정합필터는 수조의 임펄스응답함수의 시역전함수로 정의되는데 필터길이에 따라 수신신호 특징 개선 정도가 좌우된다 본 연구에서는 인공수조에서 부가되는 반사파들의 효과를 보상하여 수신신호 특징 개선을 위해 정합필터배열처리기법을 적용할 때 각 센서의 정합필터의 시간길이가 특징 개선에 미치는 영향을 신호대잡음비(SNR)로 정의하여 분석하였고 수조의 특성에 따른 최적의 정합필터 시간길이를 제안하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.5
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• pp.1054-1065
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• 1993

A computer simulation is performed on the effectiveness of the active minimization of harmonically excited enclosed sound fields for producing global reduction in the amplitude of the pressure fluctuations. In this study for the appreciable reductions in total time averaged acoustic potential energy, $E_{pp}$, the transducer location strategies for three dimensional active noise control is presented based on a state space modal which approximates the closed acoustic field.In this study, the above theoretical basis is used to investigate the application of active control to sound fields of low modal density. By the used of room-like 3-dimensional rectangular enclosure it is demonstrated that the reductions in $E_{pp}$ can be achieved by using a single secondary source, provided that the source is placed within the half a wavelength from the primary source and placed away from nodal line of the sound field. Concerning the reductions in $E_{pp}$ by minimzing the pressure in sound fields by the use of 3-dimensional rectangular enclosure, the effects of the number of sensors and the locations of these sensors are investigated. When a few modes dominate the response it is found that if only a limited number of sensors are located away from nodal line and located at the pressure maxima of the sound field such as at each corner of a rectangular enclosure.

• Journal of the Korean Society for Precision Engineering
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• v.26 no.7
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• pp.51-57
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• 2009

In this paper, we studied on an attenuation effect of automobile exhaust noise according to the direction of canceling speaker in duct-acoustic ANC system. Automobile exhaust noise was recorded at 800rpm, 3500rpm and 5000rpm of a diesel engine. Directions of canceling speaker can be set to $30^{\circ}$, $90^{\circ}$ and $150^{\circ}$ against the primary noise flow by acrylic ducts to be made for the experimentation. DSP board used to control the ANC system. The algorithm of this ANC system applied the Filtered-x-LMS algorithm that is modified to compensate for a property of DSP input signal and the secondary-path effect. As an experiment result, the direction of canceling speaker was proved to influence the reduction effect of noise. The $150^{\circ}$ duct in the attenuation effect of noise showed a better result than the $90^{\circ}$ or $30^{\circ}$ duct.

• Cartoon and Animation Studies
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• s.15
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• pp.221-235
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• 2009

Most of the sounds used in animated films are artificially made. A large number of the sounds used are either actual sound recordings or diversely processed artificial sounds made with professional sound equipments such as synthesizers. One animation episode contains numerous amounts of sounds, resulting in significant sound production costs. These sounds have full potential to be reused in different films or animations, but in reality we fail to do so. This thesis discusses ways these sound sources can be acknowledged as added new values to the present market situation as a usable 'digital content'. The iTunes Music Store is an American Apple company product that is acknowledged as the most successful digital content distribution model at the time being. Its system's sound library has potential for application in the Korean sound industry. In result, this system allows the sound creator to connect directly to the online store and become the initiative content supplier. At the same time, the user can receive a needed content easily at a low price. The most important part in the construction of this system is the search engine, which allows users to search for data in short periods of time. The search engine will have to be made in a new manner that takes into consideration the characteristics of the Korean language. This thesis presents a device incorporating the Wiki System to allow users to search and build their own data bases to share with other users. Using this system as a base, the Korean animation sound library will provide development and growth in the sound source industry as a new digital sound content.