• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.34-36
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• 1998

In these days the hybrid interrupters are widely used for medium voltage class circuit breakers. In the design of the hybrid interrupter, the shape of the short-circuit ring is one of the most important design parameters. Recently the investigation into the phase difference between arc current and magnetic field due to the shape variation of the short circuit ring has been conducted. In this paper, the results of eddy current analyses in the hybrid interrupter and test result are presented.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.2
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• pp.17-22
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• 2013

We investigated the optimum bonding conditions for thermo-compression bonding of electrodes between flexible printed circuit board(FPCB) and rigid printed circuit board(RPCB) with Sn-58Bi solder as interlayer. In order to figure out the optimum bonding conditions, peel test of FPCB/RPCB joint was conducted. The peel strength was affected by the bonding conditions, such as temperature and time. The fracture energies were calculated through F-x (Force-displacement) curve during peel test and the relationships between bonding conditions and fracture behaviors were investigated. The optimum condition for the thermo-compression bonding with Sn-58Bi solder was found to be temperature of $195^{\circ}C$ and time of 7 s.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2003.09a
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• pp.154-157
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• 2003

In order for testing faults of combinatorial logic circuit, the authors have developed a new diagnosis method: "Neural Network (NN) fault diagnosis", based on fm error back propagation functions. This method has proved the capability to test gate faults of wider range including so called SSA (single stuck-at) faults, without assuming neither any set of test data nor diagnosis dictionaries. In this paper, it is further shown that what kind of fault models can be detected in the NN fault diagnosis, and the simply modified one can extend to test delay faults, e.g. logic hazard as long as the delays are confined to those due to gates, not to signal lines.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.150-152
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• 2008

It is necessary to improve the time efficiency in the high power testing station because tests are mainly performed by high-priced equipment. Minimizing a human error through building the database of relevant standards is possible to expect reliable tests. And also, application program that is properly customized for the certain laboratory's power system will help test engineer to easily analyze the phenomenon that is happened in short-circuit and load switching tests. This paper introduces the several functions of the application program that is developed in order to realize these requirements.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.1
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• pp.85-92
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• 2018

In this paper, we designed a 150W LED lighting SMPS circuit operating at $-40^{\circ}C$. We designed a 150W LED lighting constant current circuit for the characteristics of the SMPS and fabricated and measured. The operating temperature range for a 150W LED lighting SMPS circuit is -40 to $70^{\circ}C$ and SMPS predicted life was 1.29-2.25 years based on 24 hours. The high acceleration life test and EMI test confirmed no abnormality.

• PNF and Movement
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• v.8 no.2
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• pp.47-55
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• 2010

Purpose : The purpose of present study was to determine effects of a task-oriented circuit training(TOCT) for lower limb on walking ability after stroke. Methods : Twenty one chronic stroke patients participated. Participants were randomly divided into either TOCT group or control group(11 experimental, 10 control). All of participants were in-patients at local rehabilitation centre and had been receiving a traditional rehabilitation program, five days a week. TOCT group have additionally undergone for four weeks, three days a week, the TOCT program but control group was not received any additional program except the traditional rehabilitation program. The 10 m walking test (10MWT), the 2 min walking test (2MWT), the step test (ST) and the figure-8 walking test (F8WT) to measure a walking ability were carried out twice before and after training. Results : After participation in the program, subjects of TOCT demonstrated a significant improvement in the scores of the 10MWT, 2MWT, the ST, the F8WT. The control group had no change on the any tests. After the training, the results to improve significantly in TOCT group compared to post-test of control group were the time of 10MWT and the time and the step of curved walking of F8WT. Conclusion : The present study suggests that the TOCT program may become a useful strategy for enhancing walking ability in the rehabilitation of stroke patients.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.7
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• pp.331-337
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• 2001

With the increasing reliability of analysis schemes and the dramatically increased calculating speed, the computer simulation has become and indispensable process to predict the interruption capacity of circuit breakers. Generally, circuit breakers have to possess both the small current and large current interruption abilities and the circuit breaker designers need to evaluate its capacities to save the time and the expense. The analysis of small current and the large current interruption performances have been considered separately because the phenomena occurring in a interrupter are quite different. To analyze the dielectric recovery after large current interruption many physical phenomena such as heat transfer, convection and arc radiation, the nozzle ablation, the ionization of high temperature SF(sub)6 gas, the electric and themagnetic forces and so forth mush be considered. However, in the analysis of small current interruption performance only the cold gas flow analysis needs to be carried out because the capacitive current is to small that the influence from the current can be neglected. In this paper, an empirical equation which is obtained from a series of tests to estimate the dielectric recovery strength has been applied to a real circuit breaker. The results of analysis have been compared with the test results and the reliability has been investigated.

• Journal of the Korea Society of Computer and Information
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• v.6 no.1
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• pp.7-13
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• 2001

As the density of VLSI increases, the conventional logic testing is not sufficient to completely detect the new faults generated in design and fabrication processing. Recently. IDDQ testing becomes very attractive since it can overcome the limitations of logic testing. This paper presents a new BIC for the internal current test in CMOS logic circuit. Our circuit is composed of Magnetoresistive current sensor, level shifter, comparator, reference voltage circuit and a circuit be IDDQ tested as a kind of self-testing fashion by using the proposed BIC.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.80-82
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• 1996

This paper deals with the effects of the volume of thermal expansion chamber on the interrupting performance in thermal expansion type 25.8kV 25kA gas circuit breaker. Model interrupters with 5 type thermal expansion chamber were designed and manufactured. Short-circuit tests were carried out for those model interrupters with 25kA breaking current. Pressure rise in the expansion chamber were measured and compared with the calculated one which was obtained from a self-developed program in our team. The analysis on the interrupting performance of each model interrupter has been done on the base of the short-circuit test results.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.80-87
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• 2008

Many researches related to the reliability of Pb-free solder joints with PCB (printed circuit board) surface finish under thermal or vibration stresses are in progress, because the electronics is operating in hash environment. Therefore, it is necessary to assess Pb-free solder joints life with PCB surface finish under thermal and mechanical stresses. We have investigated 4-points bending fatigue lifetime of Pb-free solder joints with OSP (organic solderability preservative) and ENIG (electroless nickel and immersion gold) surface finish. To predict the bending fatigue life of Sn-3.0Ag-0.5Cu solder joints, we use the test coupons mounted 192 BGA (ball grid array) package to be added the thermal stress by conducting thermal shock test, 500, 1,000, 1,500 and 2,000 cycles, respectively. An 4-point bending test is performed in force controlling mode. It is considered that as a failure when the resistance of daisy-chain circuit of test coupons reaches more than $1,000{\Omega}$. Finally, we obtained the solder joints fatigue life with OSP and ENIG surface finish using by Weibull probability distribution.