• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.1
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• pp.10-16
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• 2004

In this thesis, improved full wave mode ZVT(Zero-Voltage-Transition) PMW DC-DC Converters are presented to maximize the regeneration ratio of resonant energy by only putting an additional diode In series with the auxiliary switch. The operation of the auxiliary switch in a half wave mode makes it possible soft switching operation of all switches including the auxiliary switch whereas it is turned off with hard switching in conventional converter. The increase of the regeneration ratio to resonant energy results in low commutation losses and minimum voltage and current stresses. The operation principles of the improved ZVT PWM DC-DC Converters are theoretically analyzed using the boost converter topology as an example. Both theoretical analysis and experimental results verify the validity of the PWM boost converter topology with the improved full wave mode ZVT PWM converters.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1394-1397
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• 2005

Hyundai LCD Inc. and LUXELL Technologies Inc. have jointly developed a 1.5" passive matrix full color OLED display ($132{\times}RGB{\times}96$, 111ppi) with characteristics of enhanced contrast ratio using black layer technology. This prototype ECR OLED was fabricated with the structure of ITO/HIL/HTL/RGB EML/HBL/ETL/LiF/Black Layer/Cathode and showed significant improvement of contrast ratio comparing with that of non-filtered OLED as well as compatible with circular polarizer OLED

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10b
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• pp.989-994
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• 2000

Nine tests to failure are performed on full-scale eight composite beams with unreinforced web opening having ribbed slabs with formed deck which are perpendicular to the steel section and one steel beam. The effects of slab width, reinforcing of stud, moving of rib, moment-shear ratio are studied. At the low M/V ratio, Vierendeel action around the high moment end of the opening is occurred and the large deflection across the opening and transverse cracking are occurred with increasing of applied load. As the M/V ratio increases, the relative deflection across the opening decreases. And at failure, full tensile strain are occurred at bottom T section of steel beam, and concrete crushes at the High Moment End of the opening. With narrow slabs, diagonal tension failure at the high moment end of the opening is occurred. And with wide slabs, rib punch-through failure is occurred near the high moment end of the opening. The implications for design are discussed.

• Journal of the Optical Society of Korea
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• v.5 no.2
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• pp.39-42
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• 2001

A new method of switching mode in AFLC cell is proposed for faster switching time and higher contrast ratio. In this mode the ″dark″ state is obtained by applying negative full voltage while the ″bright″ state is achieved by applying positive full voltage to the cell. The switching time is reduced to 100 $mutextrm{s}$ for the cell whose switching time is 22 ms when operated in conventional mode. The contrast ratio is also improved vastly with this method. The possibility of achieving gray scale was shown in this mode of operation.

• Journal of Biosystems Engineering
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• v.34 no.2
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• pp.71-76
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• 2009

This study was conducted to investigate the load acting on a tractor engine when it delivers the maximum power at drawbar. The results of the drawbar tests on the 5 locally-made and 14 imported tractors conducted at NIAE in 2004, and the 15 tractors tested at OECD test stations in foreign countries were analyzed and presented by the torque load ratio, defined as a ratio of the engine torque load caused by drawbar pull to its full-load capacity, as a function of pull speed. The NIAE test results showed that the torque load ratio increased from 20 to 80% with pull speed less than 5 km/h. At speeds faster than 5 km/h, it was 80${\sim}$110% regardless of the pull speed. However, the OECD test results showed that the torque load ratio was evaluated mostly to be 70${\sim}$90% in the entire pull speed range. The same trend was also shown for the maximum drawbar load. The difference in the torque load ratio may be attributable to bias-ply tires for locally-made and some imported tractors. It is also suggested that the input torque load may be increased safely up to 120% of the full load capacity of the tractor engine for an accelerated life test of tractor transmissions.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.2
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• pp.109-116
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• 2019

This paper carried out numerical analysis for estimating the propulsion performance of the model scale ONRT benchmark model of'Tokyo 2015 a workshop on CFD'. The method reflecting the scale effect of ITTC'78 method and form factor were used to compare the estimates of the effective wake ratio of full-scale. The numerical calculation was performed with Siemens's Star-CCM+, compared with IIHR model tests and the numerical analysis results of other research institutes, showing good agreement. In the case of an open stern and twin skeg ship, the validity of the ITTC'78 method can be confirmed by assuming that the effective wake ratio estimated from the numerical analysis results of model scale is similar to the effective wake ratio of full-scale.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12A
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• pp.1260-1266
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• 2007

Error propagation of source-relay (S-R) link limits the performance of decode-and-forward (DF) relay and prohibits DF relay from achieving full diversity gain. In order to solve this problem, the proposed deployment strategy focuses on two objectives. One is to achieve full diversity gain, and the other is to minimize the used power of the DF relay system. In order to achieve full diversity, the error probability of S-R link should be lower than that of maximal ratio combining (MRC) at destination without error propagation since the error probability of the weaker link dominates the total error probability. The proposed strategy of relay positioning points out the range of the relay position for achieving full diversity, and the used power of the relay is minimized by this range. Analysis of error probability and simulation results prove that the two objectives are achieved by the proposed strategy of the relay position.

• Journal of Yeungnam Medical Science
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• v.35 no.2
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• pp.187-191
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• 2018

Background: Respiratory distress syndrome (RDS) is a one of the most common cause of respiratory morbidity and mortality in neonates. This study was conducted to investigate the risk factors for RDS in full-term neonates. Methods: We conducted this retrospective study using medical records. The study group included 80 full-term neonates diagnosed with RDS and hospitalized in the neonatal intensive care unit between January 2012 and December 2016, at Yeungnam University Hospital. We analyzed sex, gestational age, birth weight, delivery method, maternal age, number of pregnancy, history of abortion, and complication of pregnancy. The control group included 116 full-time neonates who were hospitalized with jaundice during the same period. Results: The incidence of full-term RDS was more common in males (odds ratio [OR], 3.288; 95% confidence interval [CI], 1.446-7.479), cesarean section (OR, 15.03; 95% CI, 6.381-35.423), multiparity (OR, 4.216; 95% CI, 1.568-11.335). The other factors rendered no significant results. Conclusion: The risk factors for RDS in full-tern neonates were identified as male sex, cesarean section, and multiparity. Further studies involving more institutions are needed to clarify the risk factors for RDS in full-term infants.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.12
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• pp.1608-1615
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• 2004

CFD data compression methods based on Full-3D and Quasi-1D supercompact multiwavelets are presented. Supercompact wavelets method provide advantageous benefit that it allows higher order accurate representation with compact support. Therefore it avoids unnecessary interaction with remotely located data across singularities such as shock. Full-3D wavelets entails appropriate cross-derivative scaling function & wavelets, hence it can allow highly accurate multi-spatial data representation. Quasi-1D method adopt 1D multiresolution by alternating the directions rather than solving huge transformation matrix in Full-3D method. Hence efficient and relatively handy data processing can be conducted. Several numerical tests show swift data processing as well as high data compression ratio for CFD simulation data.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.518-519
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• 2012

This paper suggested a fuel cell generation system which combined interleaved full-bridge converter with half-bridge inverter. High ratio step-up converter is essential to use the power as general voltage source. Full-bridge converter has high efficiency and can boost the input voltage to high output with transformer. With series connected capacitors, interleaved full-bridge converter and half-bridge inverter are combined. Half-bridge inverter has two fewer switches compared to full-bridge type. Also, switching loss can be reduced. The performance is verified through simulation with 1.5[kW] fuel cell generation system.