• 한국컴퓨터정보학회논문지
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• 제24권11호
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• pp.153-161
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• 2019

본 논문에서는 소의 목 넘김 소리를 이용하여 소의 사료 섭취량을 측정할 수 있도록 하는 방법을 제안하였다. 목 넘김 소리를 측정하기 위해 소의 목에 부착한 웨어러블 장치를 통해 녹음을 하게 되는데, 목장 사육환경에 따라 많은 소음이 함께 녹음되어진다. 이처럼 백색 잡음(white noise)이 섞여 들어간 원시 사운드 데이터를 스펙트럼화 하고, 필터를 이용한 신호 변환을 통하여 백색 잡음을 제거할 수 있는 방법을 제안하였다. 이를 통해 사료 섭취량을 측정할 수 있도록 하였다. 제안된 백색 소음 제거 방법을 통하여 소의 목 넘김 소리만을 추출하는 것이 가능하였고, 이를 통하여 소의 목 넘김 횟수 측정이 가능하였다. 본 논문에서 제안된 방법을 통하여 손쉽게 소의 사료섭취량을 측정할 수 있게 됨으로써 발정기 예측, 건강관리, 그리고 사료 관리 등이 효율적으로 이루어질 수 있게 되었다.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.181-188
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• 2001

The evaluation of the noise for the an existing engine was carried out to improve the current noise level. The applied techniques were 1m air-borne noise, combustion noise analysis, torsional analysis at the front pulley and sound pressure intensity. In addition, the evaluation of the possibility to the noise reduction by means of wrapping the parts was performed to propose the detailed information in engine design. In view of the obtained results, the following countermeasures were recommended to reduce the current noise level through the above methods. Furthermore, in order to assess the influence of combustion noise on the overall engine noise, the noise test was also performed by the change of intake air temperature up to 5$0^{\circ}C$ in steps of 1$0^{\circ}C$. Finally, the fixed design specifications to reduce the engine noise will be decided in consideration of the test data for proto type engine.

• 한국소음진동공학회논문집
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• 제25권8호
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• pp.546-552
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• 2015

In the previous study, the air flow noise around 1.6 k~1.8 kHz was analyzed, and could be reduced by machining a groove in the bore of compressor inlet in front of the main blades of a compressor wheel. It was proven that this groove was very effective for removing the noise without critical sacrifice of compressor performance, and in addition, it did not noticeably deteriorate vehicle performance, drivability and acceleration. It is interesting that the type of groove tried for 1.6~1.8 kHz noise reduction could be effective for another air flow noise, 4 k~6 kHz which is the 3rd order frequency range of turbocharger speed. This study tried various shapes of grooves for minimizing engine performance difference as well as reducing the 3rd order noise. Finally, it was shown that the groove should be round for the engine performance, and an optimal size exist for the noise and the engine performance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1371-1374
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• 2007

A few intake stations have vibration problems caused by pipes. The vibration transffered from pipes excites building severely. Therefore, the crack is generated on building wall and people who work at intake station are damaged. In this paper, the vibration is measured and analysis is carried out for pipes at intake station in order to identify the usefulness and effectiveness of the solution proposed for pipe resonance avoidance. According to the result of analysis, bellows is reduced the vibration of pipes.

• 한국동물위생학회지
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• 제31권3호
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• pp.415-423
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• 2008

This study examined the effects of the daily noise stress on body weight, feed intake and clinicopathological findings in Korean indigenous goats. A total of 14 male goats was divided into 2 groups (test and control) with same number (n=7), and exam was started 2 weeks later. This study composed 2 stages. First was noise stage i.e., noise (80-100 dB) inflicted on the test for 70 minutes each time (5 times/day), and have continued for 2 months. Second was no noise for 2 months. Body weight and daily gain in stress group was decreased compared with control group after imposing noise (first stage). However, these results were reversed after ceasing noise (second stage). Average daily feed intake was not significant different between two groups throughout the experimental periods. But, feed conversion ratio was lowerin control group than another. Clinicopathological findings including total protein, albumin, globulin, total bilirubin, total cholesterol, triglyceride, aspartate aminotransferase (AST), alanine aminotransferase (ALT), glucose, amylase, blood urea nitrogen (BUN), cortisol, total leucocytes and hemoglobin value showed no significant different between stress and control group.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.190-193
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• 2005

The air filter in engine intake system filters the dirt in the breathing air but also it attenuates the noise although the phenomenon has been regarded negligible. For the analysis of the acoustical performance of air filter, an acoustical model is suggested in this paper. The air filter consists of a porous filter element, which catches the particulate dirt, and a plastic filter box, which supports the filter element. Fibrous structure of the filter element is modeled as a micro-perforated panel using the flow resistivity and porosity. The pleated geometry of the filter element is modeled as two coupled ducts and a mathematical model is developed for the analysis of sound propagation. The filter box Is modeled as a rigid rectangular box. By combining two models, a 4-pole transfer matrix for the air filter is derived. The transmission loss calculated using the transfer matrix of the suggested model is compared with the measured data. Reasonably good agreement is observed. The result can be improved by considering the visco-thermal effect in modeling, in particular at a frequency range near the troughs of TL curve.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.913-917
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• 2007

The turbocharger for a vehicle is consisting of a centrifugal compressor and turbine. These compressor and turbine are vibrating and emitting noises through the T/C body, exhaust system (Catalyst, Bellows, Pipe, etc) and Intake system (Hoses, Intercooler pipes, Intercooler) as rotating. A turbocharger cold test bench is constructed to reduce these noises, especially for the purpose of realizing transient operating environment and oil temperature control to simulate the vehicle operating characteristics with intake system and exhaust system. This research laid the groundwork to develop a lower noise level T/C through understanding the mechanism of the noise source of T/C.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.617-618
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• 2013

• 한국자동차공학회논문집
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• 제19권3호
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• pp.90-98
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• 2011

Noises from diesel engine are the major issues for noise pollution as well as affect customers' purchasing needs to vehicles powered by diesel engine. This study investigates to screen-out main factors that contribute to noises from diesel engine using VGT 2000cc engine developed recently. Changes of fuel temperature, intake temperature and the presence of three way catalyst don't affect the 'Engine Radiation Noise' and the solely three way catalyst influence on the 'Tail Pipe Noise'. Especially, there are no effects of the presence of three way catalyst on torque, which is main subject that should be considered in secondary study.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.166-172
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• 1998

In contrast to the conventional intake manifold of steel or aluminum material, the lst natural frequency range of plastic intake manifold becomes very lower to ca. 40Hz. That causes negative effects on the engine control unit installed inside the throttle body. In this paper, support design concepts to increase the natural frequency range larger than max. 200Hz are suggested based on the vibration analysis results using finite-element method. In conclusion, it is shown that the vibration level can be reduced most effectively by the installation of the neck support bracket between the throttle body and the plenum chamber.