• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.417-419
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• 1999

본 논문에서는 최근 선진국에서 활발히 연구되는 EMF 차폐 대책의 일환인 수동루프에 대한 이론적 분석 방법을 제시하고, 고속철도 금전선 주변에서의 자계 저감효과를 보이고자 한다. 그 결과 수동루프를 이용하여 자계 저감효과를 확실하게 나타낼 수 있었다.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1393-1395
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• 2000

본 논문에서는 최근 선진국에서 활발히 연구되는 EMF 차폐 대책의 일환인 수동루프에 대한 이론적 분석 방법을 제시하고, 고속철도 급전선 주변에서의 자계 저감효과를 보이고자 한다. 그 결과 수동루프를 이용하여 자계 저감효과를 확실하게 나타낼 수 있었다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.2
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• pp.293-305
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• 1994

In this paper the efficient channel models of the subscriber loops for the ISDN U-interface digital transmission are presented. Several configuration medels of the loop network are adopted from the CCITT recommendations, and various parameters specifying the physical dimensions are determined in accordance with the measurements of the loop characteristics of Korea. A typical loop interfacing circuit is applied at both ends of the loops and the overall transmissing circuit model is obtained. Based on this circuit model of transmission. 3 types of signal path models, related to transmission, echo, and near end crosstalk noise are defined and their transfer function are respectively derived as the channel models. As examples of the proposed channel models, numerical calculation has been performed for some loop configuration models and the channel responses are investigation in both domains of frequency and time. It is shown that various changes of the loop characteristics can well be explained in terms of the proposed models. And these models can efficiently be used for the simulation of the digital transmission over the subscriber loop.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.788-792
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• 2013

There are three significant noises from the sunroof while driving. Among them, sunroof tilt-up noise has mainly high-frequency characteristics in the side and rear openings of sunroof. Because of complex structures to operate sunroof, significant flow disturbance makes strong turbulent noise. In this study, sunroof tilt-up noise was predicted by using numerical simulation code and the results were compared with experimental data.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.3
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• pp.201-209
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• 2001

Some passenger cars with sunroofs open at tilted positions experience reverse flows into cabin rooms and wind noises much louder compared to other cars. In this study, flows around open sunroofs are numerically studied with the variations of body leakage. The effects of body leakage on ventilation and wind noise of a sun roof are examined, in particular. Furthermore, flow visualization, pressure, and noise measured from wind tunnel and road tests are presented. The results show that too small body leakage results in poor performance of ventilation and generates high wind noise around a sunroof. It is therefore very important to secure an adequate body leakage from the early design stage to achieve better performance of a sunroof as well as passengers' comfort related to HVAC(Heating, Ventilation, and Airconditioning).

• Journal of Korean Society of Transportation
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• v.20 no.5
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• pp.163-174
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• 2002

Speeding has been reported as one of the major causes for fatal traffic accidents in Korea. The resolution against this dangerous speeding comes to make the automated speed enforcement system an enforcement tool. The speed detection device, which measures speeds of each incoming vehicles using double loop sensors, requires high accuracy. The object of this study is to develop an accurate speed measurement algorithm using double loop detectors. Some important findings are summarized as follows: 1) It was found that speed measurement errors are caused by scanning rate, distance of two loops, irregular vehicle trajectories, multiple vehicles in detection zone. 2) A proposed algorithm using two signal set proved to reduce variance as well as mean of speed measurement. 3) A proposed filtering algorithm was effective to filter irregular driving vehicles and multiple vehicles in detection zone. A comprehensive field test of developed algorithm resulted in significant improvement of speed measurement accuracy.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.3
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• pp.17-22
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• 2006

Sunroof is getting widely used in automobiles since it maintains, compare to window, better air circulation as well as less noise while driving in high speed. In this study, we consider an electronic control type spoiler sunroof which slides backward after tilting a rear part of a glass. Installing a wind deflector on the sunroof reduces noise much more effectively. The height of the wind deflector is designed using a boundary theory related to incompressible air layer. The developed wind deflector is investigated experimentally by measuring a wind noise. When the height of the wind deflector is designed by a fixed type, the sunroof maintains a very quiet interior noise over a certain driving speed, nevertheless it produces relatively loud noise in low driving speed.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.191-192
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• 2015

국내 배전계통은 일반적으로 수지상 계통으로 운영하고 있으며 배전선로 내 과부하 해소 및 배전계통의 유지보수를 위해 상시 개방점과 구분 개폐기를 통해 루프계통으로 운전하는 경우가 있다. 이 과정은 신속한 고장 구간 분리 및 무정전 절체를 위해 루프계통 운전 시 흐르는 루프조류 등을 정확히 고려하여 판단해야 한다. 특히 배전계통 내에 에너지저장장치(Energy Storage System, ESS) 등의 분산전원이 다수 도입된 이후로, 배전계통이 기존의 단방향에서 양방향 전력공급의 특징을 갖게 됨으로 인해 기존의 루프계통 운전에 대한 판단에 추가적인 과정을 필요하게 된다. 따라서 본 논문은 배전계통 내 에너지저장장치가 연계된 경우, 루프계통 운전을 위한 에너지저장장치의 출력변동에 대한 판단을 PSCAD/EMTDC로 모델링하여 수행한다.

• Geotechnical Engineering
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• v.34 no.1
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• pp.57-71
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• 2018

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.44 no.11
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• pp.60-66
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• 2007

In this paper, a novel voltage-controlled oscillator (VCO) using the microstrip square open loop multiple split ring resonator (OLMSRR) is presented for reducing the phase noise property. The square-shaped multiple split ring resonator (MSRR) having the form of the microstrip square open loop is investigated to realize this property. Compared with the microstrip square open loop resonator and the microstrip square open loop split ring resonator (OLSRR) as well as the conventional microstrip line resonator, the microstrip square OLMSRR has the larger coupling coefficient value, which makes a higher Q value, and has reduced the phase noise of VCO. The VCO with 1.7V power suppIy has the phase noise of $-124.5\;{\sim}\;-122.0\;dBc/Hz$ @ 100 kHz in the tuning range, $5.746\;{\sim}\;5.84\;GHz$. The figure of merit (FOM) of this VCO is $-203.96\;{\sim}\;-201.6\;dBc/Hz$ @ 100 kHz in the same tuning range. Compared with VCO using the conventional microstrip line resonator, VCO using the microstrip square open loop resonator and VCO using microstrip square OLSRR, the phase noise property of VCO using the proposed resonator has been improved in 25.66 dB, 8.34 dB, and 4.5 dB, respectively.