• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.1
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• pp.42-48
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• 1988

MM(multimode) PWM(pulse width modulation) Suitable for high performance and harmonic effects minimization of VSI (voltabge source invertetr)-IM (induction motor)drive system is proposed. The approximated optimal, suboptimal and optimal PWM are implemented in the low frequency range, while square wave operation is realized in the hibh frequency range. The pulse width Modulator is capable of generating control signals to a transistorized inverter operating at about 1KHz. All functions except digital comparison have been implemented in softyware making the scheme economical, flexible and reliable. Pulse width modulator is built and tested experimentally. In order to confirm the effectiveness and the reliability of the theoretical proposition, this scheme is applied to 1Hp, Three phase IM. As results, it is concluded that the scheme of MM PWM is superior to other conventional switching scheme through the discussions or analysis carried out on the items such as line-to-line voltage, current and spectrum of current harmonic components observed at the output terminal of inverter, noise level of motor.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.412-417
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• 2007

The energy efficiency and environment-friendly aspect of the railway system would be superior to other on-land transportation systems. In a preliminary feasibility study stage, the energy efficiency and problems related with environment are usually not considered. Selection of optimal railway line is taken into consideration include of the purpose of railway, geographical features and facility of management. The railway Alignment which could be reasons of environmental problems are focused and studied in this paper. This study performed opinions of specialists, checking of industrial environment, analysis of bid guideline to select the optimal line and executed AHP method to make quality model and choose weight factors. The investment for railway systems could be encouraged by the considering of main environmental elements evaluated with the modified noise and vibration standard for environment-friendly railway construction.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.3
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• pp.452-466
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• 1996

The purpose of this study is to proviede basic data for designing sports-brassiere by a questionnaire survey about sports-brassieres preferences and physiological wearing test. The results of the survey and the physiological wearing tests on sports-brassieres are as follow; 1. According to the survey, dissatisfied factors on the sports-brassiere are "drooping and vibrating of the breasts". Preferable factors are supporting breasts by stretch and seldom changing its position by motion. The bigger cup-size and more hemispherical-type causes more discontent than flat-type. 2. The shape of breasts is oval, on what ground, horizontal line is longer than vertical. For the cross section of bust line, shirts type.brassiere is more gently curved than cup-brassiere. 3. The feeling of wearing comfort is correlated with bust.up, shield, close adhesion. The vibration of breasts is correlated with covering urea and close adhesion, and the changing band's position by movement, close adhesion. Too much covering area or strain are in inverse correlation of the comfort. 4. The rate of prevention of vibration is 75~80% on superior sports-brassieres, which has broad covering area and excellent close adhesion. adhesion.

• Nuclear Engineering and Technology
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• v.33 no.2
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• pp.201-208
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• 2001

The high power RF transmission line components are required for transmitting MW level RF power continuously in RF heating and current drive system which heat the plasma and produce plasma current in fusion reactor The liquid stub and phase shifter is proposed as the superior to the conventional stub and phase shifter. Experimental results show that they are reliable and easy to operate compared to the conventional stub and phase shifter. There is no distortion of reflected power during the raising of the liquid level. RF breakdown voltage is over 40kV. Temperature increment of the liquid is expected not to be severe. These results verify that the liquid stub and phase shifter can be used reliably in the high power continuous RF facilities.

• Journal of Power Electronics
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• v.16 no.6
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• pp.2057-2066
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• 2016

An extension of the one-cycle control (OCC) method for switched-capacitor (SC) converters is proposed in this paper, featuring a fast dynamic response, wide line and load operation ranges, and simplicity in implementation. To illustrate the operation principle of this nonlinear control method and to demonstrate its simplicity in design, a dual-phase unity gain SC converter is examined. A new control loop based on the charge balance in a flying capacitor is formulated for the OCC technique and implemented with a 15W dual-phase unity gain SC converter on a circuit board for control verification. The obtained experimental results show that external disturbances can be rejected in one switching cycle by the OCC controlled SC converter with good line and load regulations. When compared to other control methods, the proposed nonlinear control loop exhibits superior dynamic performance in suppressing input and load disturbances.

• Bulletin of the Korean Chemical Society
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• v.33 no.11
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• pp.3635-3639
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• 2012

A series of new diarylureas possessing aminoisoquinoline scaffold was synthesized, and their in vitro antiproliferative activity against A375P human melanoma cell line was tested. Compounds 1d, 1l, 1n, 1p, 1q, and 1t showed superior potency against A375P to Sorafenib. The highest potency was shown by compound 1p possessing 3,5-bis(trifluoromethyl)phenyl terminal ring with $IC_{50}$ value of $0.41{\mu}M$.

• The korean journal of orthodontics
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• v.21 no.3
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• pp.581-590
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• 1991

This study was carried out for the comparison of the head postures between mouth breathers and normal nasal breathers. For this purpose, a test group of 28 mouth breathers, between the ages of 8 to 12 years old and a control group of 25 nasal breathers were used. Following results were obtained after comparing the craniofacial and craniocervical angulations to the True Vertical line. 1. In the comparisions relating to the True Vertical Line, results were obtained using four items; NSL/VER, FH/VER, NL/VER, PMV/VER. Variations were observed in all the items and the craniofacial angulations in the mouth breathers group showed more superior position compared to the control group. 2. In the comparisions relating to the craniocervical angulations, results were obtained using four items; NSL/OPT, FH/OPT, NL/OPT, PMV/OPT. Variations between the two groups were observed only in the PMV/OPT item and the mouth breather group showed more craniocervical angulations compared to the control group.

• Journal of the Korean Institute of Educational Facilities
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• v.18 no.1
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• pp.11-19
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• 2011

This study was carried out to investigate consciousness of users about management of multipurpose space introduced in open planned elementary school after the year of 1990's. Thirteen open planned elementary schools were participated through questionnaire and interviews. As the results, the positive response was maintained a superior position in the need of multipurpose space and changes of classroom management. Independence type in the arrangement of multipurpose space and the additional corridor type having extra moving line in comparison with the extensional corridor type were remarkably preferred, respectively. The consciousness of utilization about multipurpose space was comparatively low in a type having traffic line in surroundings of classroom compared to a type having entrance or a type having roundabout corridor. Finally, the group accepting changes positively showed high need to solve urgent problems about management of classroom.

• Journal of the Korean Institute of Navigation
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• v.5 no.2
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• pp.41-47
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• 1981

Many new radar techniques have appeared on the electronic scene in recent years, such as a variety of automatic computer processing. However, even with the advent of these sophisticated radar techniques, an old problem continues to plague all radars: the problem of transmission line losses. With the higher performance required today, the Waveguide testing and trouble-shooting techniques remain essentially unchanged in principle. This paper dealt with the rf pulse "Time-domain Reflectometry" to inspect radar wave-guide system and compared with the conventional methods. During the investigation, it was verified that the pulsed TDR for wave-guide is superior to the conventional methods; 1. Disassembling is not needed to locate the discontinity points and measure the reflections of trobled points. 2. The results of the data are more precise. 3. The condition of individual component is able to the photographed and recorded permanently. 4. Since rf pulse TDR is based on the well-known basic radar principle, such a test set requires the minimum of training to operate. With the level of transmission line problems, the prospect of increasing complexity of equipment, and no relief in sight, the benifits must be emphasizied to adopt such a testing procedure.procedure.

• Journal of Advanced Marine Engineering and Technology
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• v.29 no.2
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• pp.225-235
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• 2005

In this Paper, it was designed the GA-fuzzy controller of a Thyristor Controlled Series Capacitor(TCSC) for enhancement of power system stability. The newly designed controller of TCSC was designed to overcome the nonlinearity such as operating point change of power system as well as to respond to disturbances as uncertainties of line parameters and line fault. So, fuzzy controller by intelligent control theory was used for it. And the fuzzy controller was optimized from a genetic algorithm for complements the demerit such as the difficulty of the component selection of fuzzy controller namely. scaling factor. membership function and control rules. Nonlinear simulation results show that the proposed control technique is superior to conventional PSS in dynamic responses over the wide range of operating conditions and is convinced robustness and reliableness in view of structure.