• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1248-1250
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• 2000

The aim of this paper is to present a review of recently used current control technique for three-phase voltage source pulse-width modulated converters. Various technique, different in concept, three current control methods are presented in this paper. Current -control methods to be applied in system are PI controller. Predictive current controller. Minimum-time current controller respectively. In initial state and transient state, the response characteristics of three current control methods are verified through simulations.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.27-30
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• 2001

This paper describes the geographical and cultural characteristics of Han river and presents a schematic design of outdoor lighting for Han river bridges. Basic design concept for Han river and detail theme for each bridge was developed. With lighting simulation program, lamp, color, and image of bridge in Han river modeled and simulated. Lighting visualizations of the three major bridges were shown and detail design concept for such bridges were introduced.

• Journal of Power Electronics
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• v.8 no.4
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• pp.363-370
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• 2008

In this paper, three kinds of PWM strategies for a three-phase current-fed dc/dc converter are proposed and compared in terms of losses and voltage transfer ratio. Each PWM strategy is described graphically and their switching losses are analyzed. With the proposed PWM C strategy, one turn-off switching of each bridge switch is eliminated to reduce switching losses under the same switching frequency. In addition, RMS current through the bridge switches is lowered by using parallel connection between two bridge switches and thus, conduction losses of the switches are reduced. Further, copper losses of the transformer are decreased due to the reduced RMS current of each transformer's winding. Therefore, total losses are minimized and the efficiency of the converter is improved by using the proposed PWM C strategy. Digital signal processor (DSP: TI320LF2407) and a field-programmable gate array (FPGA: EPM7128) board are used to generate PWM patterns for three-phase bridge and clamp MOSFETs. A 500W prototype converter is built and its experimental results verify the validity of the proposed PWM strategies.

• Korean Journal of Radiology
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• v.1 no.1
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• pp.3-4
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• 2000

• Journal of Plant Biology
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• v.15 no.s
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• pp.33-49
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• 1972

Recently two thousand year old several villages ruins discovered at Amsadong, Daeshimli and Hunbaukol near the Han River side in Korea. An investigation of the present flora of these three localities was done. There are 84 families including 419 species of vascular plants. The vegetations of flora in the localities of the Han River side are very similar. the forests are poorly developed and appear as the secondary vegetations. The reforest plants can be recognized as Pinus rigida, quercus acutissima, Q. serrata, Robinia pseudoacacia and Alnus hirta. Herbaceous plants of Miscanthus sacchariflorus and Phragmitis japonicus bind up the soiles of the Han River side. Populus nigra grows abundantly in the moist places of sand bars which are located on the river side south of Daeshimli and on the northern side of the Han River across from Hunbaukol. These three area are fully cultivated but still many primitive farm techniques are employed. Farm produce crops include rice, corn, barley wheat, other vegetables, and a few ornamental plants. In this study the author found flower color variations ranging from a dark blue to a pale blue, and chromosome number differences existing between the populations of Commelina communis. The dark blue flowered taxa chromosome number is 44 and in the pale blue taxa it is 72. The wild white flowered Chrysanthemum is Chrysanthemum zawadskii Herb. ssp. acutilobum and which has finely lobed leaves, and has 54 chromosome in the root tip cells.

• Journal of the Regional Association of Architectural Institute of Korea
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• v.21 no.6
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• pp.119-128
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• 2019

The aim of this study is to examine the characteristics of facade expression designed by Kim. Han-sup, a key architect in the regional modern architecture movement in Gwang-ju and Jeonnam from the 1950's to 1960's. The study begins with the architectural background and thoughts of Kim. Han-sup through literature reviews and introduces an interview with Han. chong-un, a former college student and employee of Kim, which explains the aesthetic architecture that appeared in his design of facades that was reasonably applied to materials, technology, structure and function in line with the economically tough period in Korea. Furthermore, in order to investigate the characteristics of his facade expression, detailed analysis items will be derived from precedent studies. This study will attempt to conclude with statements that his aesthetic architecture can be defined as an emphasis on formative mass by contrasting between basic rectangular forms, implementation with detailed three-dimensional facade by extruding differently vertical and horizontal structural lines and with the pursuit of decoration through compartmental faces on his 12 representative architectural works.

• Herbal Formula Science
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• v.25 no.4
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• pp.437-447
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• 2017

Objective : Zhang zhi-cong insisted the theory related to the 'Six-meridian qi transformation', and Zhen xiu-yuan inherited that theory understanding six-meridian disease of "Shang-Han-Lun". This emphasizes that the disease of 'three yin and three yang' in "Shang-Han-Lun" is a disease caused by Six-meridian qi transformation, not a lesion of meridian itself. He said, "If you do not know brightly in the 'Tip, Root and Middle qi', you can not read the "Shang-Han-Lun"." Therefore, in this paper, we examine the interpretation of the "Shang-Han-Lun"by using the theory of 'five circuits and six qi'. Method : First, extract sentences related to 'Tip, Root and Middle qi' from the sentences of "Shang-Han-Lun" Second, the sentence is interpreted through the Zhen xiu-yuan's "Sang han lun qian zhu". Third, the meaning of the sentence is examined and summarized. Result : Zhen xiu-yuan proposed a clear and systematic theory that can understand the meaning of Six-meridian in "Shang-Han-Lun", by utilizing the discipline that 'Tip, Root and Middle qi' Conclusion : The change of 'Tip, Root and Middle qi' is a very central theory that explains the properties of 'Yin and Yang' and mutual correspondence among Korean medicine theories. It also provides basic directions for understanding the changing patterns of disease.

• Journal of the Korean Institute of Landscape Architecture
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• v.27 no.2
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• pp.119-129
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• 1999

It may be said that ancient wild Chinese garden had been founded during Qin dynasty and completed through Han, Sui and Tang dynasties. At first used as hunting areas for kings, the ancient resort forests began to take forms of garden. They dug a pond in the garden and made a simulated mountains with the soil that came from the excavations for the pond and suc pavilions has Gyong, Ru, Gak etc. were built around the pond. The ponds were different in size from those in Korea, being of the lake-like size. they made three island in the pond, which were the islands of Taoist hermits with supernatural powers, called Bong-lae, Young-ju and Band-jang respectively. the traditional of making those islands began in the Qin era and were completed in the Han era, being descended to posterity as a traditional garden structure of 'three islands in one pond' garden style. Such style was brought to Korea and first appeared as Kung-Nam-Ji in Back-jae kingdom and then brought to Japan, becoming the tradition of constructing ponds from early Heian era. Those lake-like huge Chinese ponds constituted the core of ancient garden where various feasts took place. Such ponds were also placed at the center of the gardens and played the roles of feasting garden ponds. Through the above-mentioned studies of the ancient Chines garden, the origin of them and the influence of the ancient Chinese ponded garden upon those of Korea and Japan were investigated.

• Journal of Electrical Engineering and Technology
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• v.6 no.2
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• pp.255-262
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• 2011

This paper proposes a grid-tied power conditioning system for fuel cell, which consists of three-phase current-fed DC-DC converter and three-phase PWM inverter. The three-phase current-fed DC-DC converter boosts fuel cell voltage of 26-48 V up to 400 V with zero-voltage switching (ZVS) scheme, while the three-phase PWM(Pulse Width Modulation) inverter controls the active and reactive power supplied to the grid. The operation of the proposed power conditioning system with fuel cell model is verified through simulations with PSCAD/EMTDC software. The feasibility of hardware implementation is verified through experimental works with a laboratory prototype with 1.2 kW proton exchange membrane (PEM) fuel cell stack. The proposed power conditioning system can be commercialized to interconnect the fuel cell with the power grid.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.227-233
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• 2011

This paper proposes a design and experiment of three phase interleaved dc-dc converter for 5kW battery charger. The charger consists of a three-phase interleaved dc-dc converter, which interfaces batteries and DC link, and a grid connected inverter. Lead-acid battery is modeled in a simple R-C model by matlab. Parameters of the battery are estimated based on step current discharging test. The battery is connected to three-phase interleaved DC-DC converter in order to reduce the ripple current to the battery and so, increase the lifetime of battery. Controller for charging and discharging mode is designed and tested in a 5kW charger prototype.