• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.10
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• pp.1034-1040
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• 2004

The latch-up current and switching characteristics of MOS-Controlled Thyristor(MCT) are studied with variation of the channel length and impurity concentration. The proposed MCT power device has the lateral structure and P-epitaxial layer in substrate. Two dimensional MEDICI simulator is used to study the latch-up current and forward voltage-drop from the characteristics of I-V and the switching characteristics with variation of impurity concentration. The channel length and impurity concentration of the proposed MCT power device show the strong affect on the anode current and turn-off time. The increase of impurity concentration in P and N channels is found to give the increase of latch-up current and forward voltage-drop.

• Management Science and Financial Engineering
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• v.19 no.2
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• pp.49-53
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• 2013

A Markov-chain Monte Carlo sampling algorithm samples a new point around the latest sample due to the Markov property, which prevents it from sampling from multi-modal distributions since the corresponding chain often fails to search entire support of the target distribution. In this paper, to overcome this problem, mode switching scheme is applied to the conventional MCMC algorithms. The algorithm separates the reducible Markov chain into several mutually exclusive classes and use mode switching scheme to increase mixing rate. Simulation results are given to illustrate the algorithm with promising results.

• Journal of Korean Society for Quality Management
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• v.41 no.2
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• pp.261-276
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• 2013

Purpose: This study intends to offer strategic implications that can be used in Korean medicine hospitals through analysis of causal relationship among factors focusing on image improvement and trust building. Methods: Differential model was introduced to test causal relationship. Questionnaire was developed, and data was collected and analyzed with Structural Equation Modeling. Results: Medical service has effects on image, trust, and CS. CS has an effect on trustworthiness, and trustworthiness has positive effect on loyalty intention and has negative effect on switching intention. Emotional attachment has moderating functions between trust and loyalty intention and between trust and switching intention. Conclusion: This study offers practical implications to relevant managers, at the same time it has limitations that omits relevant study of inducing factor for emotional attachment.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12A
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• pp.1985-1991
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• 1999

In this paper, complete and general two-port lumped Spice-network model is developed for a lossy transmission line. This model is realized as a Spice subcircuit, by means of standard lumped network elements and mathematical functions. It is used as a component in the time-domain simulation of a high-speed data transmission line such as IMI(Inter Module Interface) data path in HANbit ACE 64 ATM switching system. The only required Spice network elements are resistance and frequency-dependent controlled-voltage sources. Such frequency-dependent sources are realized by utilizing the standard Hspice mathematical functions FREQ, DELAY, and POLY.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.5A
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• pp.574-582
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• 2004

This paper shows the performance comparisons of several different rate scheduling schemes for non-real time data service over the uplink of burst switching-based direct sequencecode division multiple access (DS/CDMA) system to support the integrated voice/data service. The closed-form solution of optimal scheduling formulation, which minimizes average transmission delay when all of the active data users are transmitting simultaneously, is presented and mathematical analyses with other rate scheduling schemes, which provide efficiency criterion of transmission delay for rate scheduling schemes, are performed. Numerical results show the analyses explicitly.

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.148-150
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• 1988

The output characteristics of VSI by transistor depend upon bias signal with drive circuit. As the CTI is one of the VSI, takes case PWM output voltage. This Inverter operation is based upon position and negative of sinusoldal PWM signal by carrier triangular wave and compared sine one. Besides, the Inverter operation system required digital signal for microprocessor, sampling method of Inverter driver signals study for get rid of generated signal is error. In the paper, the method of 3 level PWM signal for CTI was studied. This method of signals depend upon caculated switching position of natural sampling with $10^{-6}$ modulation error for time flowchart programs.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.3-5
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• 2001

When a fault occurs on distribution network. blackout region may happen, then it should be restored as fast as possible to minimize interruption of electric service. In this paper. A near optimal method to restore distribution network is proposed. For an optimal restoration, the number or switching operations must be minimized. The proposed method generates a general restoration plan for any distribution network fault and designed to reduce switching operations considering available load transfers. In this method overall process time can reduce with heuristic rules, which make a reduction of search space before restoration process. To achieve a near optimal solution, multiple load transfer algorithm is proposed too.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.641-642
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• 2006

The modelling of some different types of switchgears has been reported in the previous papers. This paper consists of two parts. The first part concerns the modelling and simulation of switching arcs with an auto-expansion circuit breaker as an example. The second part focuses on the simulation of the PTFE nozzle ablation effect with three different nozzle shapes. For circuit breakers, the modelling of moving contact and the choice of time steps are discussed before typical results are given and compared with available test result.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2005.05a
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• pp.192-200
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• 2005

A high speed address recovery technique for AC plasma display panel(PDP) is proposed. By removing the GND switching operation, the recovery speed can be increased and switching loss due to GND switch also becomes to be reduced. The proposed method is able to perform load-adaptive operation by controlling the voltage level of energy recovery capacitor, which prevents increasing inefficient power consumption caused by circuit loss during recovery operation. Thus, th e technique shows the minimum address power consumption according to various displayed images, different from prior methods operating in fixed mode regardless of images. Test results with 50' HD single- scan PDP(resolution : $1366{\times}768$) show that less than 350ns of recovery time is successfully accomplished and about $54\%$ of the maximum power consumption can be reduced, tracing minimum power consumption curves.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.4
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• pp.15-21
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• 2004

High speed on-off electro-magnetic valves have been used for pressure control or flow control in automotive or construction machine servomechanisms. These systems require quicker valve switching speed to improve control preciseness. The authors designed and manufactured an electric valve driver with quick response characteristics by using 3 power source type valve driver concept. In experiments by using a hydraulic system incorporating the new valve driver, the new driver shortened the switching lag time from 5 ms to 1.3 ms. And also the new driver showed excellent position tracking control performances.