• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.197-202
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• 2005

Current Optical Disk drive is dominating high share gradually in information storage device market through development of great skill. These technologies can achieve not only improvement of transmission speed but also elevation of recording/reproduction technology. However, these present state cause not only the increase of vibration in structural viewpoint but also problem of serious noise while the ODD becomes high speed/high performance. Specially, air-born noise is being bigger than structural-born noise as disk rotation speed increases gradually. The object of this research is that reduce the air-born noise in optical disk drive by reducing a quantity of flow by using a miniaturized muffler. The micro muffler is a miniaturized muffler. The muffler is used widely by solution to reduce air-born noise which is generated by flow. According to frequency band of the noise source, it can be applied by muffler of various forms. In this research, we examined the noise characteristics of the micro muffler and applied it by noise reduction solution of the ODD. It could get an excellent noise reduction in high frequency band by using the micro muffler than the opened case through the decrease of an inner flow. But it could not get a noise reduction in low frequency band through the decrease of an inner flow.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.537-542
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• 2000

When visual intrusion Is an Important factor, it is desirable to find alternative methods of Improving the insertion loss of a noise barrier without Increasing the height. Therefore, the primary object of the work attenuate the noise due to railway by small interference device installed at noise barrier edge. In this paper the performance of noise barriers with attached interference device, in terms of shape, absorptive material and split panel, we examined using the boundary element approach. Also, the scale models are mounted in an anechoic chamber and the frequency of the sound sources are appropriately scaled to simulate full scale site conditions. Lastly, experimental measurements of the designs are executed for a range of frequencies and receiver positions, and are compared with the results of numerical modeling.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11b
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• pp.166-169
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• 2005

The best sunroof wind noise quality is mainly related to the sunroof deflector which affects both low-speed buffeting and high-speed aerodynamic noise. An automatic deflector-moving and noise-measuring apparatus is developed to obtain hundreds of measuring data which haven't been available by hand. With an additional program for fast and easy noise analysis, this device leads quickly to the better position and angle of the deflector. Now, the 'better' means the lower noise level and the robuster design solution. From these kinds of better solutions, more meaningful guidelines on the deflector design and sunroof wind noise reduction can be suggested.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.05a
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• pp.1053-1056
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• 2007

The acoustical performance of noise reducing devices installed on the top of a noise barrier were tested by small-scale outdoor tests. Noise measurements before and after installation of the devices were carried out using sound intensity methods. It is well known that the sound intensity method can specify the strength and directivity of sound, and it is convenient to consider the feature of sound around a noise barrier. The noise reduction effect of each edge device was evaluated using the difference between the input and output sound power levels calculated from sound intensities. It was investigated that each device had different efficiency in the shadow zone, while there was no significant difference between edge devices in the illuminated zone.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.331-341
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• 2013

In the present work, the effect of the gate-to-drain capacitance ($C_{gd}$) on the noise performance of a symmetric tied-gate $In_{0.52}Al_{0.48}As/In_{0.53}Ga_{0.47}As$ double-gate HEMT is studied using an accurate charge control based approach. An analytical expression for the gate-to-drain capacitance is obtained. In terms of the intrinsic noise sources and the admittance parameters ($Y_{11}$ and $Y_{21}$ which are obtained incorporating the effect of $C_{gd}$), the various noise performance parameters including the Minimum noise figure and the Minimum Noise Temperature are evaluated. The inclusion of gate-to-drain capacitance is observed to cause significant reduction in the Minimum Noise figure and Minimum Noise Temperature especially at low values of drain voltage, thereby, predicting better noise performance for the device.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.480-483
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• 2000

We developed a home electric panel board with surge protection device to protect home electric appliances from transient overvoltages and electromagnetic(EM) noise. In this paper, electrical characteristics of the home electric panel board are described. From the performance test using a combination surge generator standardized in IEC 610004-5, it is confirmed that the proposed home panel board has an excellent surge protection performance. Also, EM noise reduction characteristics of the panel board in ranges from 150 kHz to 30 MHz is estimated by using a network analyser, and the results showed that the panel board has an over 20 45 noise reduction performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.132-137
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• 2003

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.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.14 no.9 s.90
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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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.157-159
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• 2010

Most digital cameras apply a Charge Coupled Device(CCD) Sensor or a Complementary Metal Oxide Semiconductor(COMS) Sensor. And the images captured these sensors include unwanted noises. In this paper, we proposed a method of the Noise Reduction(NR) about noise reduction or recovery in the image. The proposed NR method is related to Bandwidth of the Low Pass Filter(LPF). For improvement of NR, we were changing the filter coefficient of the LPF. The results of simulations with various filter coefficients, [1 2 1] in the LPF and [-1 2 -1] in the High Pass Filter(HPF) have ideal frequency bandwidth and high performance. We proposed a filter coefficient [1 2 1] and [-1 2 -1] in the LPF and the HPF respectively.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1784-1786
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• 1996

It is necessary to eliminate the broad band noise which frequency is in a few kHz to MHz in the AC line to supply the power to electrical and electronic control equipments. Because this kind of noise could damage the device or could be a source of malfunction, many devices like a filter and surge suppressor are developed to cut off the noise. But those device could not disconnected from the power line, so it remain some problem and on be used in limited area, In this paper, we present performance test results NCT(noise Cut Transformer) with excellent performance for reducing the high frequency noise and surge existing in the power line.