• Proceedings of the KSR Conference
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• 2008.11b
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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.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.3
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• pp.161-168
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• 2019

This study introduces a new topology to decrease the voltage stress experienced by a 13.56 MHz electrical variable capacitor (EVC) circuit with an asymmetrical switch structure applied to the impedance matching circuit of a radio frequency (RF) plasma system. The method adopts a symmetrical switch structure instead of an asymmetrical one in each of the capacitor's leg in the EVC circuit. The proposed topology successfully reduces voltage stress in the EVC circuit due to the symmetrical charging and discharging mode. This topology can also be applied to the impedance matching circuit of a high-power and high-frequency RF etching system. The target features of the proposed circuit topology are investigated via simulation and experiment. Voltage stress on the switch of the EVC circuit is successfully reduced by more than 40%.

• Journal of the Korea Institute of Military Science and Technology
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• v.27 no.2
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• pp.197-202
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• 2024

In this study, we propose a method to improve the durability of rotorcraft switches. Additionally, the appropriate verification test results are presented. As a result of analyzing the defective switch, it was found that the contact was defective due to long-term use. It was confirmed that stable contact of the terminal is necessary to achieve appropriate performance. We manufactured a switch with one spring and a switch with two springs. As a result of the verification test using this, it was found that the durability of the improved shape was improved by 15 % compared to the existing shape. Those numbers have merit from an operational perspective. This has the effect of reducing the number of replacements per aircraft.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.1
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• pp.101-108
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• 2017

As the quantum gate matrix is a $r^{n+1}{\times}r^{n+1}$ dimension when the radix is r, the number of control state vectors is n, and the number of target state vectors is one, the matrix dimension with increasing n is exponentially increasing. If the number of control state vectors is $2^n$, then the number of $2^n-1$ unit matrix operations preserves the output from the input, and only one can be performed the unitary operation to the target state vector. Therefore, this paper proposes a new method of function embedding that can replace $2^n-1$ times of unit matrix operations with deterministic contribution to matrix dimension by arithmetic power switch of the unitary gate. The proposed function embedding method uses a binary literal switch with a multivalued threshold, so that a general purpose hybrid MCU gate can be realized in a $r{\times}r$ unitary matrix.

• Journal of Chest Surgery
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• v.31 no.10
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• pp.931-938
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• 1998

Background: Anatomic correction of transposition of the great arteries by means of the arterial switch operation is now accepted as the therapeutic method of choice. This retrospective study attempts to assess the results of the neonatal arterial switch operation for transposition of the great arteries performed by our newly established institution. Materials and methods: 33 consecutive neonates underwent the arterial switch operation between October 1991 to November 1997. There were 27 neonates with transposition and intact ventricular septum, 3 with ventricular septal defect, and 3 with Taussig-Bing anomaly. The mean age was 10.9$\pm$7.9 days and mean body weight was 3.29$\pm$0.44kg. Results: Overall postoperative hospital mortality was 30.3% (10 patients). The mortality has improved with time; 75% (6 patients) among first 8 consecutive patients before 1994, 20% (2 patients) among 10 patients in 1994 and 1995, and 13.3% (2 patients) among 15 patients since 1996. Univariated analysis of risk factors revealed that earlier date of the operations and one of preoperative events were determinants for operative death. There were two late deaths. A mean follow-up of 17.4$\pm$16.5 months was achieved in all 21 survivors. All were in New York Heart Association functional class I. One patient had mild pulmonary stenosis and two had mild aortic valve regurgitation on their echocardiography. Conclusions: We concluded that we should continue to perform arterial switch operation for neonates with transposition of the great arteries because the mortality of the operation has been improved and the operative survivors have good functional results with low incidence of late complications.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.5
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• pp.1037-1050
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• 2000

A goal of a BISDN network is to provided integrated transport for a wide range of applications such as teleconferencing, Video On Demand etc. There require multipoint communications in addition to conventional point-to-point connections. Therefore multicast capabilities are very essential in multimedia communications. In this paper, we propose a new multicast cell scheduling method on the Parallel Multicast Packet Switch with Ring network: PMRN which are based on separated HOL. In this method, we place two different HOLs, one for unicast cells and the other for multicast cells. Then using non-FIFO scheduling, we can schedule both unicast cells and multicast cells which are available at the time in the input buffer. The simulation result shows that this method reduces the delay in the input buffer and increases the efficiency of both point-to-point network and ring network and finally enhances the bandwidth of the overall packet switch. A goal of a BISDN network is to provided integrated transport for a wide range of applications such as teleconferencing, Video On Demand etc. There require multipoint communications in addition to conventional point-to-point connections. Therefore multicast capabilities are very essential in multimedia communications. In this paper, we propose a new multicast cell scheduling method on the Parallel Multicast Packet Switch with Ring network: PMRN which are based on separated HOL. In this method, we place two different HOLs, one for unicast cells and the other for multicast cells. Then using non-FIFO scheduling, we can schedule both unicast cells and multicast cells which are available at the time in the input buffer. The simulation result shows that this method reduces the delay in the input buffer and increases the efficiency of both point-to-point network and ring network and finally enhances the bandwidth of the overall packet switch.

• Proceedings of the KIPE Conference
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• 2004.07a
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• pp.330-334
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• 2004

A new SEPIC-Flyback converter is proposed. The proposed converter is the integration of SEPIC and Flyback converter. Not only SEPIC output but also Flyback output could be fully regulated by constant frequency PWM control. Merged SEPIC and Flyback topology can share the transformer and power MOSFET. When the switch turns on, one topology operates via capacitive energy transfer. The other topology acts as inductive energy transfer while the switch is off. So, it can increase power density per one cycle. The experimental result is presented and verified.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.1
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• pp.78-84
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• 2011

In this paper, the switching frequency and THD for the reduction instead of traditional single phase inverter using a new type of central arm of the single phase inverter is proposed. The proposed single phase inverter topology, the existing one to add a arm by two-way central switch 3-level output voltage can be raised and, central arm, especially one or two of the switches by using a switch to the diode current switching algorithm was simplified. During the dead time because of this, depending on the direction of the current level does not appear in any other existing level compared to the inverter output voltage level of the THD has the advantage that less can be. The simulation and experimental results verified the validity of the proposed topology.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.1
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• pp.70-76
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• 2000

This paper describes a one-chip micom controller and phase angle control method for self-starting and energy saving of single-phase induction motor. The proposed method is based on the optimal efficiency control which is running by variable phase angle of main winding current such as to maintain the maximum efficiency characteristics of the motor, in voltage control with TRIAC. Experiments are focused on a capacitor starting single-phase induction motor. The optimal energy saving by variable phase angle control are verified by experimental results. Also, auxiliary winding was controlled by electronic starting switch.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.526-529
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• 2004

A new SEPIC-Flyback convater is proposed. The proposed converter is the superposition of SEPIC and Flyback converter. Not only SEPIC output but also Flyback output could be fully regulated by constant frequency PWM control. Merged SEPIC and Flyback topology could share the transformer and power MOSFET. When the switch turns of one topology operates via capacitive energy transfer. Another topology acts as powering mode while the switch is off. So, it could increase power falsify per one cycle. The operating principle of the proposed converter is described below. Prototype featuring 24V input 48V output, 100kHz switching frequency, and 100W output is simulated under the proposed topology.