• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.774-775
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• 2015

In this paper, a series of electromagnetic analyses carried out for a high efficiency 22.9/0.38kV mold transformer are presented. The simulations were performed in order to calculate the losses which eventually verify the performance(efficiency) of the designed product. Here, losses include core loss, stray losses of non-current carrying metallic structural parts(core plate and clamp), ohmic loss and eddy current loss of current carrying metallic parts(busbars, leads, terminals and windings). The obtained results of the simulations were compared to the test results and showed high level of accuracy. The loss evaluation technology will allow designers avoid any potential over-design or under-design of the high efficiency products, reducing the manufacture cost and development period compared to the conventional experience-based design procedures.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.2
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• pp.103-108
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• 2009

Local exhaust system used in toilet and cooking place of low-rise public house installed roof ventilator at terminal of stack. There are many high riser public houses in Korea. These buildings were not viewed as being major contributors to exhaust pollutants producted in indoor. It was because many engineers thought that exhaust in high riser public house depends on stack effect. But Neutral pressure level represents in a terminal of stack with air tightness for the best exhaust efficiency. Thereby, lower floors have the worst indoor air quality. This paper focuses mainly on the exhaust efficiency improved by roof fan with motor installed in high riser public house. It is observed there is higher exhaust efficiency than the existing natural roof ventilator.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.102-105
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• 2005

For transferring the primary power to the secondary one, the high frequency series resonant converter has been widely used for the contactless power supply system. However, the high frequency series resonant converter has the disadvantages such as the low efficiency, the high voltage gain characteristics and deviation of the phase angle in the overall load range. To improve this disadvantage, In this paper, the characteristics of the high efficiency and unit voltage gain as well as in phase are revealed in the proposed three-level LCLC ( Inductor - Capacitor - Inductor -Capacitor)resonant converter. The results are verified on the simulation based on the theoretical analysis and the 4kW experimental prototype.

• Journal of Power Electronics
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• v.16 no.2
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• pp.447-454
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• 2016

A single-ended primary-inductor converter (SEPIC) features low input current ripple and output voltage up/down capability. However, the switching devices in a two-level SEPIC suffer from high voltage stresses and switching losses. To cope with this drawback, this study proposes a three-level SEPIC that uses a low voltage-rated switch and thus achieves better switching performance compared with the two-level SEPIC. The three-level SEPIC can reduce switch voltage stresses and switching losses. The converter operation and control method are described in this work. The experimental results for a 500 W prototype converter are also discussed. Experimental results show that unlike the two-level SEPIC, the three-level SEPIC achieves improved power efficiency with balanced capacitor voltages.

• Journal of Acupuncture Research
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• v.24 no.4
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• pp.55-68
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• 2007

Objectives : This research was performed to investigate the effect of herbal acupuncture(Crataegus pinnatifida) at WI-SU($BL_{21}$) on weight gain, food intake, food efficiency, serum of lipid concentrations, liver function and cardiovascular risk of rats fed high fat diet for 8weeks. Methods : Experimental groups were divided into high fat diet group(Control), high fat diet and saline in $BL_{21}$ treated group(Saline), high fat diet and Crataegus pinnatifida-herbal acupuncture in $BL_{21}$ treated group(HA-1, 0.08mg/ml/g), high fat diet and Crataegus pinnatifida-herbal acupuncture in $BL_{21}$ treated group(HA-2, 0.04mg/ml/g), high fat diet and Crataegus pinnatifida-herbal acupuncture in $BL_{21}$ treated group(HA-3, 0.016mg/ml/g), Herbal acupuncture was bilaterally treated at Crataegus pinnatifida-herbal acupuncture in both $BL_{21}$ 1time (0.2cc) per 4days, total 14 times in 56days. Results : Body weight was decreased in HA-1 and food efficiency was decreased in HA-1, HA-3. Feed intake was increased in HA-3. The level of serum total cholesterol was decreased in Saline, HA-1, HA-2, HA-3. The level of serum HDL-cholesterol was increased in HA-1, but LDL-cholesterol was not significant. The level of serum triglyceride was decreased in HA-1, HA-2, HA-3. and the level of serum Total Bilirubin was decreased in HA-1. The level of serum Atherogenic index was decreased in HA-1, HA-2, HA-3. and the level of serum HTR was increased in HA-3. The evel of serum AST, ALT were increased in saline, and the level of serum r-GTP was not significant. Conclusions : Crataegus pinnatifida acupuncture in Wi-Su($BL_{21}$) can control the body weight, feed intake and feed efficiency ratio, total cholesterol, HDL-cholesterol, triglyceride, total bilirubin, and prevention cardiovascular risk. And Crataegus pinnatifida acupuncture is not injurious on liver function.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.11
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• pp.1174-1182
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• 1990

A hgih efficiency and good dynamic performance drive system of an induction motor is presented in this paper using vector control technique. If the induction motor is driven under light loads with rated flux, the iron loss is excessively large compared with the copper loss, resulting in poor motor efficiency. High efficiency drive of an induction motor can be achieved by adjusting the flux level which leads the total motor loss to be a minimum value. Generally reducing the flux degrades the dynamic performance, but the dynamic performance of the proposed system is also maintained high. If the d-axis is coincident with rotor flux phasor in synchronous rotating reference frame, the stator current can be decoupled as flux component and torque component. At steady state, the developed motor torque is proportional to the product of the flux and torque component. The combination of the two components minimizing the motor loss could be found with numerical method. As the procedure to obtain the optimal combination is too hard, it is found experimentally. The system block diagram is suggested for maximum efficiency control. The proposed system is studied through digital simulation and verified with experiment. The experimental results show the possiblity of a high efficiency drive with good dynamic performance of maximum efficiency control.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.565-566
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• 2008

The high efficiency power management IC(PMIC) for Moblie application is proposed in this paper. PMIC is controlled with PWM control method in order to have high power efficiency at high current level. The saw-tooth generator is made to have 1.2 MHz oscillation frequency and full range of output swing from ground to supply voltage(VDD:3.3V). The comparator is designed with two stage OP amplifier. And the error amplifier has 70dB DC gain and $64^{\circ}$ phase margin. DC-DC converter, based on Voltage-mode PWM control circuits, achieved the high efficiency near 95% at 100mA output current. DC-DC converter is designed with LDO in stand-by mode which fewer than 1mA for high efficiency.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.533-539
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• 2004

The rotary compressor is widely used for the air conditioner because it is efficient and compact. In recent, the need for silent and efficient compressors is much stronger than the past. The new type muffler was invented to reduce noise level and to improve efficiency. The new type muffler that has two side discharge holes and dome shape represents much lower overall noise level, especially noise levels around 1kHz than the old type one that has one center discharge hole In acoustic spectra. Also it has higher air conditioner efficiency by lower oil discharging amount of a compressor than old type one that has rectangular shape and two side discharge holes. The noise reduction and efficiency improvement effects of the new type muffler were verified by tests for rotary compressors and air conditioners.

• Journal of Acupuncture Research
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• v.25 no.2
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• pp.211-226
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• 2008

Objectives : This research was performed to investigate the effects of Fructus Hordei Germiniatus-herbal acupuncture(HA; herbal acupuncture) at acupoint Jung-wan($CV_{12}$) on weight gain, food consumption, food efficiency, serum of lipid concentrations and liver function of rats fed high fat diet for 7weeks. Methods : Experimental groups were divided into high fat diet group(Control), high fat diet and saline injection at acupoint $CV_{12}$ treated group(Saline), high fat diet and Fructus Hordei Germiniatus-HA at acupoint $CV_{12}$ treated groups. According to HA concentration, HA groups were classified into 4 groups ; HA-1($0.108mg/g/m{\ell}$), HA-2($0.054mg/g/m{\ell}$), HA-3($0.022mg/g/m{\ell}$), HA-4($0.011mg/g/m{\ell}$). HA was treated at $20{\mu}{\ell}$ per 4days, total 12times in 49days. Results : 1. Body weight per week was significantly decreased in HA-1, HA-2, HA-3 and HA-4 And body weight per day was significantly decreased in HA-3. 2. Food consumption per week was significantly decreased in HA-1, HA-2, HA-3 and HA-4. 3. Food efficiency per week was significantly decreased in HA-2, HA-3 and HA-4 And food efficiency per day was significantly decreased in HA-3. 4. The level of serum total cholesterol was significantly decreased in HA-1 and HA-3 And the level of serum HDL-cholesterol was significantly decreased in HA-1. 5. The level of serum triglyceride was significantly decreased in HA-1, HA-2, HA-3 and HA-4. And the level of serum total bilirubin was significantly decreased in HA-1and HA-2. 6. The level of serum AST was significantly decreased in HA-2 and HA-3 And the level of serum ALT, r-GTP were significantly decreased in HA-2. Conclusions : According to the above results, Fructus Hordei Germiniatus-HA at acupoint $CV_{12}$ can control body weight, food consumption, food efficiency, serum lipid concentrations and liver function. Asthe same time this kind of Fructus Hordei Germiniatus-HA does not seem to be injurious on liver function. To use Fructus Hordei Germiniatus-HA for obesity, further studies about their underlying mechanism may be needed.

• Journal of Korea Society of Digital Industry and Information Management
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• v.11 no.3
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• pp.31-43
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• 2015

In this paper, we discuss a code generation technique for custom transport triggered architecture (TTA) from a high-level language structure. This methodology is implemented by using TTA-based Co-design Environment (TCE) tool. The results show how the scheduler exploits instruction level parallelism in the custom target architecture and source program. Thus, the scheduler generates parallel TTA instructions using lower cycle counts than the sequential scheduling algorithm. Moreover, we take Tensilica tool to make a comparison with TCE. Because of the efficiency of TTA, TCE takes less execution cycles compared to Tensilica configurations. Finally, this paper shows that it requires only 7 cycles to generate the parallel TTA instruction set for implementing Cyclic Redundancy Check (CRC) applications as an input design, and presents the code generation technique to move complexity from the processor software to hardware architecture. This method can be applicable lots of channel Codecs like CRC and source Codecs like High Efficiency Video Coding (HEVC).