• 한국소음진동공학회논문집
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• 제14권9호
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• pp.861-867
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• 2004

For the evaluation of acoustic noise of a DLP projector, vibration and sound characteristics of a DLP projector were studied. The acoustic noise of DLP projector could be classified into three categories, that is, the direct noise from a body of rotation, the air-bone noise generated from turbulence or vortex occurred during cooling process and the structural born noise produced by vibrating elements. Cooling fans and color filter wheel which rotates at 9000 rpm are main causes of acoustic noise induced in DLP projector. Since the structure of an optical module in a DLP projector can be excited by the excessive vibration of a color filter wheel, the structural design for anti-vibration should be considered. To make a reduction of overall acoustic noise, the anti-vibration design and the enclosing structure have been studied and applied to a color filter wheel.

• 한국음향학회지
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• 제40권1호
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• pp.84-91
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• 2021

승강기는 고층아파트에서 매우 중요한 설비기기이다. 이러한 승강기가 운행할 때 발생하는 소음은 거주민에게 불편함을 주고 있다. 하지만 승강기 소음에 대한 법규 및 규정은 없는 실정이며, 승강기 소음을 측정하고 평가하는 방법 또한 명확하지 않다. 이러한 문제는 승강기 운행 시 발생하는 소음과 진동의 특성 파악이 우선 시 되어야 한다. 본 연구에서는 고층아파트 로프식 승강기 운행 시 발생하는 소음과 진동을 측정 층수와 측정 실의 종류에 따라 나누어 측정 하였다. 소음과 진동의 동시 측정을 진행하여 소음과 진동의 특성을 파악하고, 상관성 분석을 통해 각 실험 조건에 따른 상관계수를 파악 하였다. 그 결과 승강기 소음은 125 Hz ~ 500 Hz 대역의 성분이 주요하고, 125 Hz ~ 500Hz 대역에서 진동과의 상관성 또한 유의미한 것으로 파악 되었다. 최상층의 경우 상관계수가 0.8 수준으로 매우 높음을 확인 하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.592-597
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• 2002

The purpose of this study was to analyze the characteristics of a new heavy weight impactor, the Rubber Ball. Until now Bang-machine has been used to measure the heavy impact noise in accordance with JIS A 1418-1. However, various kinds of examination methods have been needed to make an objective observation of insulation capacity for floor impact noises. Two types of experiments were undertaken. First, the experiment about noise was carried out about an apartment building in actual living condition. Then. vibration noises from the impactors were analyzed. The results of this study were as follows : the result of experiment carried out with bonded area of bail was closer to practical experiment than that of non bonded area. In addition, the result about bonded area of ball was more similar to the result which is claimed by H. Tachibana than that about non bonded area. Moreover, it was found that Rubber Ball has more similar vibration characteristics to the real impact noise source than Bang-machine.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 춘계학술대회논문집
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• pp.1425-1431
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• 2006

In this study, An analysis of correlation between the vibration transmissions and the dynamic characteristics for floor impact sound insulation materials through model test was carried out. As the results, the correlation coefficients between the vibration transmissions and the dynamic characteristics for floor impact sound insulation materials were over 0.8 at the heavy and light floor impact source and less dynamic stiffness was more effective in reducing the vibration transmission.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.861-865
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• 2001

Generally the noise and vibration characteristics of 4WD vehicle is closely related to the characteristics of driveline such as bending mode, torsional mode, unbalance and nonuniformity of propeller shaft. In this paper the 4WD vehicle which has body vibration problem in high speed driving condition was tested. The sources of the body vibration and its transfer path are investigated by experimental approach. According to the experimental assessment, the body vibration is caused by the nonuniformity of joint of propeller shaft. And this paper presents a kinematic model of a vehicle driveline for the optimization of a driveline characteristics. Finally the optimized result of the drive line has been verified through the experiment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1459-1462
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• 2005

The paper deals with the structural vibration and noise characteristics of pipe structures. In general, A structure bone noise has a great effect on the drain noise of toilets, and depends on the natural frequency of the related structures. In order to measure and to find the relationships between structural vibration and noise of the pipe structures, some experiments have been performed. Through the experiments, impact acceleration signal in time domain and magnitude of transfer function in the frequency domain have been investigated for three kinds of pipes. Transmission loss of pipes depending on the frequency ranges was also found by using small speakers as a sound source.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2012년도 춘계학술대회 논문집
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• pp.307-308
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• 2012

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.348.1-348
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• 2002

This paper deals with the vibration reduction of the hull mount system of ship structures brought by ER smart structures. The hull mount is used to isolate the vibration form the immersed structures. Utilizing the tunable characteristics of ER fluids, ER insert are made In the hull mountint structure. Different types of ER inserts are proposed and the vibration characteristics are investigated. (omitted)

• 한국소음진동공학회논문집
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• 제14권3호
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• pp.185-192
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• 2004

Vibration table is required to obtain high packing density in expendable pattern casting process. Packing density. which is an important manufacture factor, depends on the vibration pattern induced by vibration table. In general, circular vibration pattern is recognized as the best pattern. The existing vibration table is investigated to identify current vibration pattern and consider a countermeasure. Modal test is utilized to identify the dynamic characteristics of vibration table, and finite element method is used to propose the improved design. In simulation using finite element method, the position of stiffeners is obtained to satisfy the required dynamic characteristics.

• 한국소음진동공학회논문집
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• 제20권11호
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• pp.1071-1077
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• 2010

The reduction of the vehicle interior noise has been the main interest of noise and vibration harshness(NVH) engineers. A passenger vehicle has various and complicated transmission paths of sound and vibration. In order to identify the mechanism of transfer path, estimation of excitation force and exact modeling of transfer path are required. This paper presents method for estimating the noise source contribution on the road noise of the vehicle in a multiple input system where the input sources may be coherent with each other. And vector synthesis technique is employed to identify the characteristics of road noise and its transmission to vehicle compartment through noise and vibration analysis. Vibration reduction efficiency of each transfer path is evaluated by comparing individual vector components obtained virtual simulation.