• 한국위성정보통신학회논문지
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• 제11권3호
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• pp.80-85
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• 2016

본 연구는 선음원과 점음원의 이론에 근거하여 개발된 혼타입 스피커와 라인어레이 타입 스피커에 대해 비교분석하여 실제에서 이론대로 적용되는지에 대해 연구하였다. 이론적으로 점음원은 거리가 2배 됨에 따라 6dB 감쇄하며, 선음원은 거리가 2배 됨에 따라 3dB 감쇄한다. 선음원 이론에 근거하여 개발된 라인어레이 스피커 시스템이 선음원의 이론대로 작은 음압감쇄가 일어나는지에 대하여 분석하여 사용 목적과 환경에 따른 올바른 스피커의 배열 구성이 선택되도록 하는 것이 본 연구의 목적이다. 이를 위해 점음원과 선음원의 이론을 분석하였으며, 이론을 바탕으로 설계된 혼타입 스피커와 라인어레이 스피커를 시뮬레이션으로 파라메터 값들을 분석하였다.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2011년도 춘계학술논문집 2부
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• pp.529-532
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• 2011

A theoretical model has been studied to describe the sound radiation analysis for structure vibration noise of vehicle tires under the action of random moving line forces. When a tire is analyzed, it had been modeled as curved beams with distributed springs and dash pots that represent the radial, tangential stiffness and damping of tire, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The expression for sound power is integrated numerically and the results examined as a function of Mach number, wave-number ratio and stiffness factor. The experimental investigation for structure vibration noise of vehicle tire under the action of random moving line forces has been made. Based on the Spatial Transformation of Sound Field techniques, the sound power and sound radiation are measured. Results strongly suggest that operation condition in the tire material properties and design factors of the tire govern the sound power and sound radiation characteristics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집 Vol.3 No.2
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• pp.1075-1079
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• 2002

This paper presents a result of sound transmitting system with power line communication technique, Sound transmitting system is a transmitter which transmits modulated audio signal to power to power line and receiver which is capable of detesting it with earphone or speaker. It has been evaluated with the frequency characteristics and spectrum analysis. And, from the result of evaluation on the developed system, we confirm the superior sound transmitting characteristics, and the possibility of application on a language laboratory.

• 조명전기설비학회논문지
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• 제18권3호
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• pp.128-134
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• 2004

본 연구에서는 전력선통신 기술을 이용하여 전송주파수에 음성신호를 변조한 후 전력선으로 전송하고 전력선으로부터 수신 및 복조하여 변조된 음성신호를 검출하는 음향전달 시스템을 제작하였다. 제작된 시스템으로부터 변복조 및 주파수 특성을 분석하여, 어학실습 교육을 위한 용도로서의 활용 가능성을 평가하였다. 그 결과 전달된 음향 신호가 최적상태는 아니지만 어학실습 교육용으로 청취하기에 충분한 수준으로 판단되었다.

• 방송공학회논문지
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• 제12권1호
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• pp.28-40
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• 2007

본 논문에서는 기존에 제안된 잔향 알고리즘 구조에서 문제점으로 대두된 잔향특성을 개선한 새로운 알고리즘 구조를 제안하였다. 제안된 알고리즘 구조는 초기 잔향을 위하여 탭 지연라인을 사용하여 초기반사음을 충분히 구현하였고, 후기 반사음과 잔향을 위해 nested allpass delay line을 이용하여 잔향 밀도를 높이도록 제안하였다. 실내음향의 파라메터를 추출하여 각 지연 라인의 지연 시간을 설정 및 조절하여 가장 좋은 잔향 효과를 갖도록 계수 값들을 설정하였으며, 제안한 알고리즘을 일반 범용 신호처리기를 이용하여 구현 및 실험 고찰을 통해 기존에 제시된 모델에서의 임펄스성음에 대한 비선형적인 거친 응답과 급격한 음색변화가 감소하여, 고르고 평탄한 잔향 밀도가 향상되어 잔향특성이 개선됨을 관찰하였다.

• 대한전기학회논문지:전력기술부문A
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• 제52권3호
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• pp.183-192
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• 2003

This paper presents the real-time implemented distance relay algorithm which the fault distance is estimated with only local terminal information. When a single-phase-to-earth fault on a two-parallel transmission line occurs, the reach accuracy of distance relay is considerably affected by the unknown variables which are fault resistance, fault current at the fault point and zero- sequence current of sound line The zero-sequence current of sound line is estimated by using the zero sequence voltage which is measured by relaying location Also. the fault resistance is removed at the Process of numerical formula expansion. Lastly, the fault current through a fault point is expressed as a function of the zero-sequence current of fault line, zero-sequence current of sound line, and line, and fault distance. Therefore, the fault phase voltage can be expressed as the quadratic equation of the fault distance. The solution of this Quadratic equation is obtained by using a coefficient of the modified quadratic equation instead of using the square root solution method. After tile accurate fault distance is estimated. the mote accurate impedance is measured by using such an information.

• 한국정보전자통신기술학회논문지
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• 제13권1호
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• pp.1-7
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• 2020

음향 시스템의 지향성 제어기술은 음향의 품질 향상을 위한 핵심 기술이다. 음향 시스템에서 점 음원이 아닌 선음원을 제공하면 원거리에서 감쇠 간섭의 영향을 줄일 수 있기 때문에, 고품질의 음향을 제공할 수 있다. 특히, 라인 어레이(line-array) 스피커 시스템을 이용하면 원거리까지 균일한 고품질의 음향을 제공할 수 있다. 그러나, 고음은 파장이 짧기 때문에 라인 어레이 시스템의 스피커간의 거리가 짧아야 하지만 물리적인 한계가 있다. 본 논문에서 이러한 문제점을 해결하기 위해 웨이브 가이드를 설계하고 스피커 유닛에 장착하였다. 개발된 스피커의 성능 확인을 위해 다양한 음향특성을 측정하고 테스트 하였다. 그 결과 개발된 스피커를 이용하여 라인 어레이 음향 시스템을 구성하면 고음 영역을 포함한 모든 영역에서 선 음원을 제공할 수 있기 때문에 단일 확장 음원과 같은 효과를 얻을 수 있고, 원거리까지 고품질의 음향을 제공할 수 있음을 확인하였다.

• 한국음향학회:학술대회논문집
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• 한국음향학회 2004년도 추계학술발표대회논문집 제23권 2호
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• pp.221-224
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• 2004

A theoretical model has been studied to describe the sound radiation analysis for structure vibration noise of vehicle tires under the action of random moving line forces. When a tire is analyzed, it had been modeled as curved beams with distributed springs and dash pots that represent the radial , tangential stiffness and damping of tire, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y=0 and to be axially infinite. The curved beam material and elastic foundation are assumed to be lossless Bernoulli-Euler beam theory including a tension force, damping coefficient and stiffness of foundation will be employed. The expression for sound power is integrated numerically and the results examined as a function of Mach number, wave-number ratio and stiffness factor. The experimental investigation for structure vibration noise of vehicle tire under the action of random moving line forces has been made. Based on the Spatial Transformation of Sound Field techniques, the sound power and sound radiation are measured. Results strongly suggest that operation condition in the tire material properties and design factors of the tire govern the sound power and sound radiation characteristics.

• 소음진동
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• 제5권2호
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• pp.169-181
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• 1995

A theoretical model has been studied to describe the sound radiation analysis for structural vibration noise control of tire under the action of random moving line forces. When a tire is analyzed, it has been modeled as a curved beam with distributed springs and dash-pots which represent the radial, tangential stiffness and damping of tire, respectively. The reaction due to fluid loading on the vibratory response of the curved beam is taken into account. The curved beam is assumed to occupy the plane y = 0 and to be axially infinite. The material of curved beam and elastic foundation are assumed to be lossless, and governed by the law of Bernoulli-Euler beam theory. The expression for sound power is integrated numerically and its results examined as a function of Mach number(M), wavenumber ratio(.gamma.) and stiffness factor(.PSI.). The experimental investigation for structural vibration noise of tire under the action of random moving line forces has been made. Based on the STSF(Spatial Transformation of Sound Field) techniques, the sound power and sound radiation are measured. The experimental results show that operating condition, material properties and design factors of the tire have a great effect on the sound power and sound radiation characteristics.

• 한국생산제조학회지
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• 제7권1호
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• pp.41-50
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• 1998

The detemination of sound pressure radiated from peoriodic plate structures is fundamental in the estimation of noise levels in aircraft fuselages and ship hull structures. As a robust approach to this problem, here a very general and comprehensive analytical model for predicting the sound radiated by a vibrating plate stiffened by periodically spaced orthogonal symmetric beams subjected to a sinusoidally time varying point load is developed. The plate is assumed to be infinite in extent, and the beams are considered to exert both line force and moment reactions on it. Structural damping is included in both plate and beam materials. A space harmonic series representation of the spatial variables is used in conjunction with the Fourier transform to find the sound pressure in terms of harmonic coefficients. From this theoretical model. the sound pressure levels on axis in a semi-infinite fluid (water) bounded by the plate with the variation in the locations of an external time harmonic point force on the plate can be calculated efficiently using three numerical tools such as the Gauss-Jordan method, the LU decomposition method and the IMSL numerical package.