• Current Optics and Photonics
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• 제3권2호
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• pp.111-118
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• 2019

The optical characteristics of a tunable flattened-pass-band fiber comb filter, based on the polarization-diversified loop configuration, are investigated using the $Poincar{\acute{e}}$-sphere representation. In the design process, the spectral flatness is checked quantitatively, and the tunability of the pass band is demonstrated experimentally. Theoretical calculations show that the filter also exhibits desirable dispersion and polarization properties. The orientation angles of rotatable wave plates for the wavelength tunability of the filter are obtained. Furthermore, we elaborate on the multiple angle loci produced by degeneracies through the combination of optical elements within the loop of the filter.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.985-992
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• 2008

A turnout system which permits trains to pass from one track to another is a combination of the switch, the crossing, lead rails which are necessary to connect the switch and the crossing, two guard rails and a switch machine for operating the switch. A turnout is the sole moving part among the railway components and has complex configuration, so the safety has always been raised an issue. In Korea, it is planned to adopt the high speed tilting train, which operates at the maximum speed of 180km/h, at conventional lines by the year of 2010. However, for the application of the tilting train to conventional lines, it is prerequisite to establish a stable turnout system allowing the tilting train to pass through it without reducing speed. Therefore, the improved turnout system for the speed-up of conventional lines has been developed and the prototype of the turnout system has been constructed. In this study, evaluation of noise characteristics around the improved turnout system was performed through the field measurements. Field measurements of noise around the conventional and the high-speed turnout system were also carried out for the comparison.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1000-1005
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• 2008

A turnout system which permits trains to pass from one track to another is a combination of the switch, the crossing, lead rails which are necessary to connect the switch and the crossing, two guard rails and switch machines for operating the switch. A turnout is the sole moving part among the railway components and has complex configuration, so the safety has always been raised an issue. In Korea, it is planned to adopt the high speed tilting train, which operates at the maximum speed of 180km/h, at conventional lines. However, for the application of the tilting train to conventional lines, it is prerequisite to establish a stable turnout system allowing the tilting train to pass through it without reducing speed. Therefor, the improved turnout system for the speed-up of conventional lines has been developed and the prototype of the turnout system has been constructed. In this study, evaluation of Vibration characteristics around the improved turnout system was performed through the field measurements. Field measurements of Vibration around the conventional and the high-speed turnout system were also carried out for the comparison.

• 재무관리연구
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• 제22권1호
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• pp.147-179
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• 2005

모기지유동화증권(Mortgage-Backed Securities : MBS)의 도입과 변화를 주도한 근본적인 원인은 투자자 혹은 차입자의 효용 제고 및 욕구 충족에 있다. 본 연구는 이러한 사실에 주목하여 MBS의 발행 구조에 따라 그 가치가 변동할 수 있음을 이론 모형으로 정립, 증명, 분석 및 해석한다. 구체적으로 자동이체증권과 PAC-Support CMO라는 차별적 발행구조의 두 MBS의 가치를 투자자의 효용의 관점에서 파악하고 발행구조에 따라 후자가 전자보다 더 큰 가치를 창출할 수 있음을 이론적으로 보인다. 한편 모기지 및 MBS의 가치평가에 재금융(refinancing)으로 인한 조기상환 위험의 평가가 매우 중요하며, 재금융은 이자율의 등락 및 과거 이자율의 경로에 의하여 크게 영향 받기 때문에 이를 3기간 모형으로 반영하여 MBS의 가치평가를 시도하였다. 특히 소진현상(burnout)을 모형에 명확히 반영하여 이 현상이 MBS의 현금흐름, 위험 및 가치에 미치는 영향을 고찰하였다. 본 연구 결과 동일한 현금흐름 및 위험을 제시하는 MBS보다 차별적으로 설계된 MBS가 선호될 수 있으며 후자의 가치를 극대화하는 최적의 발행 구조가 존재함이 인정된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.588-590
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• 1996

An AC induction motor or constant speed characteristics has been widely used as power source because of simple structure and low maintenance cost in industrial field. The variable frequency AC source with a conventional inverter which is composed or power semi-conductors and drive systems contains much noises in sine wave current due to high speed switching or direct current. In this paper, the low pass LC filter for a variable speed induction motor driven by a full bridge inverter is introduced to solve EMI problem originated by much noise current. The modified LC filter based on the 3rd order Butterworth LC filter is used for the computer simulations and real experiments. The characteristics or proposed LC filter are investigated through FET analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.854-857
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• 2001

At present, colonoscopy is performed by means of quite long and flexible endoscopes and controlled manually. Although the flexibility of the distal tip allows the endoscope to follow the tortuous path of the colon, the insertion of the endoscope requires the endoscopist to exert forces on and to perform rotations of the proximal end; these actions cause discomfort to the patient. Though self-propelling colonoscopic systems has been suggested to overcome these problems, it is difficult to pass through highly curved regions of the intestine. In this paper, we introduce a steering mechanism for a self-propelling coloinlscope, the smart capsule, which has three actuator units. The mechanism is designed not only to move forward and backward but also to pass through the curved regions. We derived the governing equations of this mechanism. Active movements and motion control are developed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.450-451
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• 2008

Most of the transmission lines in Korea pass through a mountains. The forest fire occurred in around the transmission lines make an accident such as flashover and faults in the power transmission lines. In spite of that risk, there are no research on the flashover characteristics by fires in electric discharge engineering in our country. Therefore, by studying flame's electrical conductivity, the paper recommended measures that can minimize transmission line's flashover accidents in the future, which can be caused by forest fire in a region where transmission lines pass through.

• 한국컴퓨터정보학회논문지
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• 제3권2호
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• pp.77-84
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• 1998

요즈음 CMOS 기술의 발전에 의해서 연속시간 신호시스템이 매우 각광을 받고 있다. 따라서 이 논문에서는 음성신호 처리영역에서 동작하는 CMOS floating 저항을 이용한저역통과 필터를 설계하였다. 특히 이 논문에서는 포화영역에서 동작하는 all CMOS floating 저항을 설계하였으며, $\pm$1V 영역에서 $\pm$0.04%의 선형성이 얻어졌다. 주파수 응답은10MHz를 초과하였으며 능동 RC회로의 집적화에 매우 유용할것으로 생각한다. 이 방법에 의해 설계도니 저역통과필터는 SC 필터보다 그 구조가 간단하므로 IC의 형태로 만들 때 칩 면적을 많이 줄일 수 있다. 설계된 필터의 특성은 pspice에 의해 시뮬레이션 하였으며, 그 특성이 우수함이 입증되었다.

• 한국전기전자재료학회논문지
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• 제11권4호
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• pp.281-287
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• 1998

$BiNbO_4$ ceramics doped with 0.07wt% $V_2O_5$ and 0.03wt% CuO (BNC3V7) were sucessfully sintered at $900^{\circ}C$ through the firing process with Ag electrode. The BNC3V7 shows typically Dielectric constant of 44.3, Thermal Coefficient of resonance Frequency(TCF) of 2 ppm/$^{\circ} and $Qxf_o$ value of 22,000 GHz. The laminated chip Low Pass Filter (LPF) is very sensitive to chip processing parameters, was confirmed by the computer simulation as a function of Q(Quality factors), filter size, capacitor layer thickness, inductor pattern widths. The multilayer type LPF was fabricated by screen-printing with Ag electrode after tape casting and then compared with the simulated characteristics. The results show that characterization of band pass width was similar to that of designed ones.

• 환경영향평가
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• 제15권6호
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• pp.453-458
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• 2006

A turnout system which permits trains to pass from one track to another consists of the switch, the crossing, lead rails which are necessary to connect the switch and the crossing, two guard rails and a switch machine for operating the switch. A turnout is the sole moving part among the railway components and has complex configuration, so the safety has always been raised an issue. In Korea, it is planned to adopt the high speed tilting train, which operates at the maximum speed of 180km/h, at conventional lines by the year of 2010. However, for the application of the tilting train to conventional lines, it is prerequisite to establish a stable turnout system allowing the tilting train to pass through it without reducing speed. Therefore, the improved turnout system for the speed-up of conventional lines has been developed and the prototype of the turnout system has been constructed. In this study, evaluation of noise characteristics around the improved turnout system was performed through the field measurements. Field measurements of noise around the conventional and the high-speed turnout system were also carried out for the comparison.