• 한국음향학회:학술대회논문집
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• 한국음향학회 2004년도 추계학술발표대회논문집 제23권 2호
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• pp.191-194
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• 2004

This study Is an measurement and prediction of transmission loss through dash panel with multi-path in a vehicle. Measurement results of transmission loss are decided by sound power measured using the sound intensity method under locating a sound source in the anechoic room and reverberant room, respectively. Prediction one is decided by multi-path analysis of dash panel composed by a various part of materials and complicated shape. Finally, two results show a great agreement between measured and predicted transmission loss.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.122-125
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• 2005

This study is an measurement and prediction of transmission loss through dash panel with multi-path in a vehicle. Measurement results of transmission loss are derided by sound power measured using the sound intensity method under locating a sound source in the anechoic room and reverberant room, respectively. Prediction one is decided by multi-path analysis of dash panel composed by a various part of materials and complicated shape. Finally, two results show a great agreement between measured and predicted transmission loss.

• International Journal of Railway
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• 제4권1호
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• pp.19-27
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• 2011

Many studies for improving the railway vehicle's performance and comfort such as speed, weight and noise are currently in progress. Improving the structural characteristics of the vehicle for greater noise insulation is considered important for reducing disturbance due to noise, but measuring transmission loss entails large costs. This study explores an alternative method for estimating and measuring the railway vehicle's transmission loss that involves on applying the numerical analysis coupled with scaled reverberation chamber measurement. The transmission loss measurement using scaled reverberation chamber was performed after the compensation value was found through 1mm thickness(1t) specimen. For numerical analysis, a commercially available acoustics solver VA ONE was used. The proposed method is found to lead to transmission loss measurement comparable to the measurements based on large-scale reverberation chamber. Thus, it can be argued that a reliable method has been developed for measuring railway vehicle's transmission loss.

• 대한기계학회논문집A
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• 제27권10호
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• pp.1720-1727
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• 2003

The object of this work is to develop the measurement method of the transmission error of the helical gears. For this purpose, experimental set up is designed by 3D CAD software. It consists of the motor, inverter, powdered brake equipment, torque sensor and helical gearbox. In this study, tangential linear accelerometers were used as the methods for the transmission error measurement. the acceleration signals are transmitted to the signal conditioners through the slip rings and the transmission errors are obtained by a specially designed circuit board. The transmission errors are analyzed in the frequency domain. As a result, The periodicity of the transmission error is confirmed in the mesh frequency and its harmonics. The magnitude of harmonic components is very dependent on the natural frequencies of the gear system. It usually increases with the rotational speed. However, it does not always increase with torque.

• 한국음향학회지
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• 제4권2호
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• pp.3-12
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• 1985

The surface intensity method is a relatively new tool which can identify the noise source or path and measure the radiation power. One microphone and one accelerometer are used in this new technique. In this study, this new technique has been used to measure the field transmission loss trough doors. The results of the experiment indicate that the surface intensity method produces reliable data and can be applied to the transmission loss measurement.

• 한국음향학회지
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• 제4권2호
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• pp.3.1-3.1
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• 1985

The surface intensity method is a relatively new tool which can identify the noise source or path and measure the radiation power. One microphone and one accelerometer are used in this new technique. In this study, this new technique has been used to measure the field transmission loss trough doors. The results of the experiment indicate that the surface intensity method produces reliable data and can be applied to the transmission loss measurement.

• 한국소음진동공학회논문집
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• 제18권5호
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• pp.550-557
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• 2008

A transmission control cable connects the transmission control arm and the control lever mechanically and transfers control effort exerted by a driver to the transmission. It also transfers vibration generated by the engine to the passenger room through mechanical connection. To understand vibration and noise transfer mechanism and to further find a way to suppress the transmission of vibration effectively, a dependable dynamic vibration model is a necessity. A vibration model for a transmission control cable is developed and a simulation study has been conducted to obtain mode frequencies and a transmittability. The resonance frequencies obtained by an harmonic analysis is compared with the noise level measurement data. The measurement agrees with the simulation result thus ensures the reliability of the model.

• 전자공학회논문지
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• 제50권2호
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• pp.35-46
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• 2013

모바일 네트워크 사용량이 급증함에 따라 트래픽 수요 문제를 해결하기 위한 많은 연구가 이뤄지고 있다. 특히 네트워크 환경 측정 분야는 정확한 분석을 통해 네트워크상에 발생되는 문제들의 원인을 찾아냄으로써 트래픽 수요 문제를 해결할 수 있는 기반을 제공한다. 특히 최근 스마트폰의 수요가 늘어남에 따라 모바일 플랫폼 특성이 네트워크에 미치는 영향을 고려한 측정시스템이 필요하다. 이에 본 논문에서는 모바일 플랫폼을 위한 네트워크 환경 측정 시스템을 설계하였다. 설계된 시스템은 클라이언트를 통하여 얻은 패킷의 정보를 통하여 패킷 전송간의 지연시간과 throughput을 실시간으로 계산한다. 그리고 측정시 클라이언트인 모바일 단말기에 요구되는 계산량을 줄임으로써 모바일 단말기에 걸리는 부하를 최소화하였다. 설계한 시스템을 통하여 네트워크 자원을 최대로 사용하였을 시 Wi-Fi 망이 3G 망보다 짧은 전송지연시간, 높은 최대 throughput, 낮은 손실률을 가지고, Android가 iOS보다 짧은 전송지연시간과 높은 최대 throughput을 가지며, UDP가 TCP보다 긴 전송지연시간, 높은 최대 throughput을 가진다는 것을 확인하였다.

• Current Optics and Photonics
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• 제3권6호
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• pp.496-501
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• 2019

We propose a method to eliminate the noise of a disordered medium optical transmission matrix. Gaussian noise exists whenever light passes through the medium, during the measurement of the transmission matrix and thus cannot be ignored. Experiments and comparison of noise eliminating before and after are performed to illustrate the effectiveness and advance presented by our method. After noise elimination, the results of focusing and imaging are better than the effect before noise elimination, and the measurement of the transmission matrix is more consistent with the theoretical analysis as well.

• Nuclear Engineering and Technology
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• 제36권1호
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• pp.12-23
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• 2004

In the present study a new measurement technique has been developed, which uses an ultrasonic transmission signal in order to identify the vertical two phase flow pattern. The ultrasonic measurement system developed in the present study not only provides the information required for the identification of vertical two phase flow patterns but also makes real time identification possible. Various vertical two phase flow patterns such as bubbly, slug, churn, annular flow etc. have been accurately identified with the present ultrasonic measurement system under atmospheric condition. In addition, the present test apparatus can practically simulate the ultrasonic propagation characteristics under high temperature and high pressure systems. Therefore, it is expected that the present ultrasonic flow pattern identification technique could be applicable to the vertical two phase flow systems under high temperature and high pressure conditions.