• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 춘계학술대회 논문집
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• pp.343-348
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• 2003

As one of countermeasures for vibration and noise source which come from train operation in subway system, the heavy-weighted tunnel structure and the low-vibration track design have been adopted. In recent the low-vibration concrete track have been constructed to enhance the maintenance effectiveness as well as the reduction of vibration. This paper is explaining and evaluating of the characteristics of vibration and its effects comparing to tile ballast track, concrete track, and full surface supported floating slab track installed on Express bus terminal in Seoul subway No. 7 line.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.787-791
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• 2013

The engine excitation forces are considered as major vibration source for the forklift truck, especially in small class. Even though the current engine mounting system designs are acceptable for vibration isolation, the performance of the engine mounting system is still required for the tendency of light weight, higher power and driver's higher vibration requirement. In this paper vibration reduction technique of forklift engine which is supported on rubber mounts is presented. Based on the dynamic model of resilient engine mounting system, design evaluation program is established. The design optimization technique and evaluation method of system properties are discussed. Effects of optimal design are validated through comparison with test results.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.997-1004
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• 2007

A hybrid technique that combines the advantages of binaural reproduction and sound field reproduction technique is proposed. The concept of HRTF-field, which is defined as the set of HRTFs corresponding to the various head dislocations, enables us to realize virtual source imaging over a wide area. Conventional $2{\times}2$ definition is redefined as a MIMO system composed of multiple control sources and multiple head locations, and HRTF variations corresponding to various head movement are quantified. Through the direct control of HRTF-field, reproduction error induced by head dislocation can be minimized in least-square-error sense, and consequential disturbances on the virtual source image can be reduced within a selected area. Simple lateralization examples are investigated, and the reproduction error of the proposed technique is compared to that of Higher-order Ambisonics.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.861-864
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• 2006

In general, 4-pole parameter and three-point method are used for predicting transmission loss which is one of characteristics of Muffler using CAE tools. However, these mehtods show different results from experiment when the flow effects are presented in practical model. In this parer, to overcome these problems, both Fluent and.Sysnoise are used to analyze the performance of extended inlet/outlet muffler including flow effects with varying flow velocity at inlet of duct. Flow fields and quadrupole source is calculated by Fluent. And Sysnoise is used to analyze acoustic performances of muffler with quadrupole source data extracted from Fluent. Finally, the variation of transmission loss is estimated according to various inlet flow velocity.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.366-370
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• 2006

In this study, characteristics of impact force and impact sound of impact source such as bang machine, impact ball, and children's jumping were review. Results of review showed that impact ball has most similar characteristic to real impact sources in terms of objective properties such as impact force and impact sound. The effects of various isolator on floor impact sound were also investigated in apartment building and test facilities building using bang machine an impact ball. From the field measurement, it was found that the difference in reduction sound level between bang machine and impact ball was relatively large and the reduction sound level by impact ball was much larger than bang machine.

• 한국소음진동공학회논문집
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• 제21권11호
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• pp.983-990
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• 2011

This paper investigates active noise control(ANC) of a rectangular cavity using single channel filtered-x least mean square(FXLMS) algorithms to globally reduce the interior noise. To obtain the global reduction of the interior noise, multichannel active control should be incorporated in general. We, however, examined firstly the optimal location of the secondary source that produces a global reduction of the interior noise field using single channel control. We then investigated the frequency characteristics of the reduction to yield the effective frequency band of the active control system. It follows that the secondary source should be located as close to the primary source as possible in order to obtain the global reduction.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.662-663
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• 2014

In most vehicle manufactures have traditionally relied on find-fix method of human auditor, mainly due to variation excitation source. To solve the BSR noise, the requirements for BSR test are presented in terms of detection of noise source, analysis of time-frequency and sound pressure, sound quality for noise. A number of new technology direction, particularly in the field of noise source identification application and psycho-acoustics from the Zwicker's sound quality parameter, the computed objective sound metrics and subjective jury test result.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.471-477
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• 1998

A constant flow-rate control valve provides effective distributions and controls of running water in a pipe system. The noise characteristics were measured to reveal the noise sources depending on pressure differences across a valve. Valve noise is mostly dominated by bubble dynamics under cavitating conditions. In this study, the sound powers from a flow control valve of constant flow rates are effectively normalized. Flow-excited dynamic systems for which there is no strong coupling between the flow and the system response can be described using a linear source-filter model. On this assumption, the normalized sound powers can be decomposed of noise source function and a response function. The source spectra in, terms of cavitation frequency show cavitation events occurring at narrow banded frequencies greater than 10 kHz. There also possibly exist two kinds of cavitating modes based on our experimental data.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.645-645
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• 2009

In many practical applications of the centrifugal fan, the impeller-diffuser interaction noise is considered as a main source of fan noise. The housing for an electric motor is also expected to play an important role on noise propagation because of its complicated configuration. This study investigates the impeller-diffuser interaction noise and its sources by computing three-dimensional, incompressible flow field of the centrifugal fan in motor housing. The effect of motor case on fan noise characteristic is then investigated using the Brinkman penalization method, while the noise source associated with impeller-diffuser interaction is mathematically modeled. It is found that the present methodology combined with mathematical description of noise source provides a fairly good agreement with the experimental results, indicating that the motor housing has significant effect on noise characteristics. Finally, aeroacoustic noise prediction for various impeller-diffuser blade count ratios is conducted for noise reduction.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.383-386
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• 2001

The KS of “Measurements of impact sound insulation of floors” was established before the years. But the KS of “Rating of floor impact sound insulation for impact source in building and of building elements” is not founded yet. To establish the rating measurement of floor impact sound insulation. The studies on the rating method of domestic floor system of impact sound insulation and response of its inhabitant’s were reviewed. And the rating method of ISO’s and JIS’s were studied in this consideration. The result of this study, KS of “Rating of floor impact sound insulation for impact source in building and of building elements” is proposed.