• Current Optics and Photonics
• /
• v.3 no.2
• /
• pp.111-118
• /
• 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.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.985-992
• /
• 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.

• Proceedings of the KSR Conference
• /
• 2008.11b
• /
• pp.1000-1005
• /
• 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.

• The Korean Journal of Financial Management
• /
• v.22 no.1
• /
• pp.147-179
• /
• 2005

It is frequently said that mortgage-backed securities (MBS) of different security designs are issued in an attempt to meet the varying needs and expectations of investors. If this is true indeed, MBS of complicated risk-return characteristics are likely to be priced higher than MBS of simple risk-return characteristics we. We test this implication by establishing a recombining binomial interest rate prepayment model with a burnout effect embedded. More specifically, we compare the relative values (utilities) of a pass-through and a PAC- Support collateralized mortgage obligation(CMO), and theoretically show why and how the CMO is more highly valued than is the pass-through. The model is established such that mortgage prepayment is a function of the current value of, and the past path of, the mort-gage market rate. Since we work on not the total value of the two MBS but the value of each tranche of either MBS, the test results could be robust to slightly different versions of similar tests, which may be done in the future.

• Proceedings of the KIEE Conference
• /
• 1996.07a
• /
• pp.588-590
• /
• 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.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2001.04a
• /
• pp.854-857
• /
• 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.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.450-451
• /
• 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.

• Journal of the Korea Society of Computer and Information
• /
• v.3 no.2
• /
• pp.77-84
• /
• 1998

The continuous time signal system by development of CMOS technology have been receiving consideration attention. In this paper, Low pass filter using CMOS floating resistor have been designed with cut off frequency for speech signal processing. Especially a new floating resistor consisting entirely of CMOS devices in saturation has been developed. Linearity within $\pm$0.04% is achieved through nonlineartiy via current mirrors over an applied range of $\pm$1V. The frequency response exceeds 10MHz, and the resistors are expected to be useful in implementing integrated circuit active RC filters. The low pass filter designed using this method has simpler structure than switched capacitor filter. So reduce the chip area. The characteristics of the designed low pass filter using this method are simulated by pspice program.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.11 no.4
• /
• pp.281-287
• /
• 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.

• Journal of Environmental Impact Assessment
• /
• v.15 no.6
• /
• pp.453-458
• /
• 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.