• 한국소음진동공학회논문집
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• 제26권2호
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• pp.121-129
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• 2016

The noise pattern of a household refrigerator is dependent on the characteristics of its operating cycle which is repeated with a specific pattern depending on various parameters, such as room temperature and performance of its mechanical parts. Analysis of noise pattern is essential prior to evaluation of sound quality of a refrigerator. In this study, 14 units of refrigerator were classified into 4 types according to noise pattern and sort of mechanical part, which helps to analyze characteristics of refrigerator noise. Sound quality metrics(loudness, sharpness, roughness, and fluctuation strength) were calculated to compare noise pattern of the 4 types of refrigerator. The results of this study can be useful to decide noise performance of refrigerator.

• 한국ITS학회 논문지
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• 제11권1호
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• pp.86-91
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• 2012

다양한 잡음환경에 노출되는 텔레메틱스 기반의 음성 통화 시스템에서 고품질의 통화 품질을 제공하기 위해서는 저연산량을 가지며 효과적으로 배경 잡음을 제거할 수 있는 잡음제거 알고리즘이 요구된다. 본 논문에서는 Mel-Filter 기반의 잡음제거 알고리즘을 제안하며, 제안된 알고리즘을 기존 잡음제거 알고리즘들과 비교하여 설명한다. 자동차 잡음과 배블 잡음 환경에서 잡음제거 알고리즘의 성능 측정 결과, 제안된 Mel-Filter 기반의 잡음제거 알고리즘이 기존 잡음제거 알고리즘들에 비해 비슷한 PESQ 성능에 적은 연산량을 가지는 장점을 가지고 있으며, 제안된 잡음제거 알고리즘이 텔레메틱스 단말기에서 효과적으로 잡음을 제거할 수 있음을 입증하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.186-189
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• 2005

Since human listening is very sensitive to sound, a subjective index of a sound quality is required. Therefore, in the analysis for each situation, the sound evaluation is composed with sound quality factor. Many researchers spends their effort to make a more reliable and more accurate of sound in term of sound quality index for various system noise. In this study a reliable index is constructed and analyzed using correlation analysis, regression analysis and weighting factor for each sound quality factor. We have made the sound quality index that agrees with more than human subjective sensitivity which apply to various sound quality metrics. Also we applied a 'grade' metric to jury for sound evaluation, analyzed relation between sound duality index and sound quality grade. Then we will judge the sound quality level according to the sound quality grade scheme.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.193-198
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• 2004

In order to keep the market competitiveness, it is desirable for automotive manufacturer to meet the customer's various aspects of requirements. The overall NVH (Noise, Vibration, and Harshness) performance has been an important measure when evaluating overall vehicle performance, product quality, and enhancing customers' loyalty to the product. The noise and vibration, while the engine is idling, has been brought particular attention to the drivers and passengers, because they encounter the operation conditions quite frequently without other masking noise sources: wind noise, road noise, and even powertrain radiated noise at higher speed driving. The specific noise, defined as 'CHIT' noise, has been identified as a potential customer issue, from the Pickup Truck with newly developed V8 powertrain. This paper describes the definition of the noise, identifying the potential sources, and noise radiation mechanisms, based on series of powertrain and vehicle test and verification processes. Then, based on the root-cause identified, the design change has been proposed and validated with several vehicles in order to have a complete satisfaction of the customer.

• 소음진동
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• 제9권4호
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• pp.841-848
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• 1999

직류 모터의 생산 공정품질 확인 작업에 있어서 전체 소음레벨이 합격점에 이른다 할지라도 관능 평가시의 이음으로 인해 불량판정을 받게되는 경우가 있다. 이런 종류의 문제는 가공 또는 조립 공정상에서 발생될수 있는데 본 눈문에서는 과도기적 스펙트럴 분석 혹은 시간-주파수 분석 기법을 소음품질 문제에 적용해 보았다.Case Study로써 윈드쉴드 와이퍼 모터의 이음 발생원이 상세 분석되었으며, 결과적으로 정상적인 주파수 분석에서 발견되지 않았던 아마추어 축의 불량이 충격소음을 일으킨것으로 밝혀졌다. 이를 통해 회전체-기어 시스템의 이음 원인규명을 위한 시간-주파수 분석 기법의 효과적 활용이 잘 나타났다.

• 한국소음진동공학회논문집
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• 제16권3호
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• pp.240-246
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• 2006

In the air-conditioner, refrigerant induced noise and vibration can be increased when the airflow rate is reduced in order to decrease the noise at the low mode. Through the test and analysis of this kind of noise, it can be verified that the main reasons of refrigerant induced noise are the velocity and flow Induced force of the refrigerant at the inlet of the evaporator, So, in order to reduce this velocity, quality at the evaporator inlet should be minimized. And, in order to reduce flow induced force of the refrigerant, sudden change of fluid flow must not be occurred. So, in this paper, we will review the characteristics of refrigerant cycle and find how the quality and flow induced force can be minimized.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.401-405
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• 2003

Sound quality is becoming a major concern in optical disc drives (ODD). In order to improve the sound quality of slim type ODDs, we changed lead screw pitch and firmware algorithm in the seek mode. To evaluate the sound quality, the PCM (Paired Comparison Method) was adopted and the result was compared with the time-averaged loudness spectrum. Sound signals were also recorded and modified by increasing or decreasing selected frequency bands to verify their sensitivities to the sound quality. As a result of jury test, preferred frequency bands are associated with the time-averaged loudness spectrum.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.286-292
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• 1997

Sound quality is becoming the major concern in passenger vehicle. The study on it has been done recently but it is not good enough. In order to improve the sound quality in passenger vehicle, so many noise sources must be considered and human feeling to the noise also be taken into account. In this paper, the sound quality was analyzed by vehicle road test which was carried out with varying the traveling speed. As basic factors for sound quality, only objective factors are considered such as loudness, sharpness, speech intelligibility, sound pressure level ... etc. The relations between sound pressure level and other factors are discussed from a point of view of traveling speed dependency. The frequency dependency of sound quality factor is also analyzed by frequency analysis.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2006년도 추계학술대회논문집
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• pp.654-660
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• 2006

There are various sounds in the car as much as cats have many mechanical parts. These sounds make various sound qualities. The international competition in car markets has continuously required the research about the sound quality of a car. The domestic carmakers have also invested a lot of money for the research and development of sound quality. Car axle plays an important role in a vehicle and its NVH development is also important. By this time, NVH development of car axle is mainly based on the reduction of sound pressure level(dBA), which cannot gives, the satisfaction to the customers in view of the sound quality of a vehicle. Therefore, in this project, a sound quality index evaluating the sound quality of axle noise based on human sensibility is developed and applied to the development of the sound quality of axle noise

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.421-426
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• 2005

For the air-conditioner, refrigerant induced noise and vibration should be the problem when it reduced airflow rate in order to reduce the noise at low mode. With the test, it could be verified that one of the main reason for refrigerant induced noise were the velocity and flowing induced force of the refrigerant at the inlet of evaporator. So in order to reduce this velocity with same mass flow rate of refrigerant, quality at the evaporator inlet should be minimized. And in order to reduce flowing induced force of the refrigerant, flowing direction change should be eliminated. So in this paper, it would like to review the characteristics of refrigerating cycle at first and find how the quality and flowing induced force can be minimized.