• 전기학회논문지P
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• 제65권2호
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• pp.114-121
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• 2016

This paper is Instant space vector PWM(Pulse Width Modulation)power conversion devices in switching power semiconductors from my generation to losses and switching when the voltage surge and current surge of electronic noise(EMI: Electro Magnetic Interference / RFI: Radio Frequency Interference)to effectively minimize the power soft-switching power conversion circuit topologies of auxiliary resonant DC tank for the purpose of high performance realization of the electric power conversion system by the high-speed switching of a semiconductor device(AQRDCT simultaneously : an active auxiliary resonance using auxiliary Quasi-resonant DC tank)DC link snubber switch has adopted a three-phase voltage inverter. AQRDCL proposed in this paper can reduce the effective and current peak stress of the power semiconductors of the auxiliary resonant snubber circuit compared to the conventional active-resonant DC link snubber, it is not necessary to install the clamp switch of the auxiliary resonant DC link, DC the peak current and power loss of the bus line can be reduced.

• Journal of Power Electronics
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• 제11권5호
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• pp.639-654
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• 2011

This paper presents a Current Distribution Control design for Paralleled Positive Output Elementary Super Lift Luo Converters (PPOESLLCs) operated in Continuous Conduction Mode using a Sliding Mode Controller (SMC). Manipulating the higher current requirement of the load through the paralleling of POESLLCs, results in a current inequality. This is mainly due to dissimilarities in the power semiconductor switches and circuit components used in POESLLCs, which may lead to converter failures. In order to balance the proper load current sharing and the load voltage regulation of PPOESLLCs, a SMC is developed. The SMC is designed for the inherently variable-structured of POESLLCs by using the state-space average based model. The static and dynamic performance of the developed controller with PPOESLLCs is validated for its robustness to perform over a wide range of operating conditions through both a laboratory prototype and MatLab/Simulink models, which are compared with a Proportional-Integral (PI) controller. Theoretical analysis, simulation and experimental results are presented to demonstrate the feasibility of the developed SMC along with the complete design procedure.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.531-532
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• 2005

We have used ITO/$Alq_3$/Al structure to study electrical conduction mechanism in $Alq_3$ based organic light emitting diode. Current-voltage characteristics were measured at room temperature by varying the thickness of $Alq_3$ layer from 60 to 400nm. We were able to prove that there are three different mechanism depending on the applied voltage; Ohmic, SCLC (space-charge-limited current). and TCLC (trap-charge -limited current) mechanism.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 학술대회 논문집
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• pp.73-77
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• 2004

Outdoor space used for leisure life as inhabitantses' recreation and rest area, and night activity is very important space to many apartment complex. Lately, outdoor space is recognized as a very important space in apartment complex. Especially, that outdoor space is frequently used at night despite planning of lighting of current outdoor space is unprepared for the selection of suitable luminaires, arrangement of luminaire and lighting plan. From this point of view, this paper investigated the essence of light in outdoor space and analyzed different outdoor luminous environment. This paper finally suggested recommended level of illuminance and planning of lighting.

• 천문학회보
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• 제39권2호
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• pp.100.1-100.1
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• 2014

Korea Astronomy and Space Science Institute (KASI) has been participating in the Giant Magellan Telescope (GMT) project since 2009. In 2014, GMT project has passed its important milestones toward construction of the telescope and observatory facilities. We will report the recent achievements and current status of the project in this contribution.

• 디자인학연구
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• 제3권1호
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• pp.83-93
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• 1990

The constant evolution of society, culture and scientific technology, coupled with changes in life style and behavioral patterns, has led mankind to peroeive diverse needs for space. Particularly, the rapid structural change in the field of marketing has entailed changes in techinques for construction and presentation of space for an improved marketing environment. To satisfy such new, diverse needs for space, interior designers will have to redefine the "mankind and environmen( concept and examine their design methodology anew. The question of how to design available space for a certain purpose will remain a daunting task for designers in the future, as it has been in the past. In the pursuit of convenience and conformity to mankind's surroundings, every nation has, in common with other nations, basic design elements, design skills and other factors. In designing camercial space in a particular region, it is essential, however, to have a proper understanding of the social economic and cultural context indigenous to that region, as well as the impact on environmental and ecological change and marketing strategy. This study discusses design metholdology for the comming camercial space on the basis of the space concept and current status in Korea, with major emphasis on Korea's regional characteristics.

• 천문학회보
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• 제41권1호
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• pp.58.1-58.1
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• 2016

K-GMT Science Program, operated by Center for Large Telescopes (CfLAT) in Korea Astronomy and Space Science Institute (KASI), aims to promote the scientific researches by providing the access to the observational facilities such as 4-8m class telescopes and specialized instruments. In 2016, we plan to make various instruments with MMT and Gemini Observatory as well as IGRINS with 2.7m HJS Telescope in McDonald Observatory available to Korean Astronomical Community. We will present the current status and future prospect as well as some early results made from the K-GMT Science Program in past years.

• 교육시설 논문지
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• 제21권6호
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• pp.25-32
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• 2014

Korean academic libraries are facing serious space shortage problems due to an inability to accommodate for the rapidly increasing number of printed materials. Despite the current situation, Korean academic libraries have largely focused on impractical applications of the new library paradigm, using technology or management programs to improve the quality of research and learning environments of the university. However, such improvements would be fruitless without first resolving the space shortage crisis. In order to make realistic improvements to the quality of academic libraries, this study used questionnaires to employ the opinions of librarians currently practicing at such Korean libraries. Survey questionnaires about types and causes of space shortage problems, library facility expansion plans, expected effects of expansion, frequency of and reasons for furniture relocation, and tight spaces needing improvement were distributed to selected 4-year college librarians through Google Drive. Analysis of survey responses indicated that library space shortage was largely responsible for the hindrance of research and learning environments. Furthermore, it reflected the urgency to secure book storage space.

• 전기학회논문지
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• 제63권10호
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• pp.1377-1383
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• 2014

This paper deals with eddy current loss of magnetic coupling with radial permanent magnet (PM) using analytical method such as a space harmonic method. Superposition of two kinds analysis model is used to analyze eddy current loss induced in inner PM and outer PM of magnetic coupling. When the eddy current is induced, the environmental temperature increases, and the permanent magnet(PM) characteristics are degraded because the performance of PM is greatly influenced by temperature rise. Hence, the calculation of eddy current loss becomes an important factor in the magnetic coupling. In order to analyze eddy current loss, first, on the basis of the magnetic vector potential and two-dimensional(2-D) polar-coordinate system, the magnetic field solutions of the radial magnetized PM are obtained. And we obtain the analytical solutions for the eddy current density produced by permanent magnet. Lastly, analytical solutions for eddy current loss are derived by using equivalent, electrical resistance calculated from magnet volume and analytical solution for eddy current density. This analytical results are validated by comparing with the 2-D finite element analysis (FEA).

• Journal of Astronomy and Space Sciences
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• 제27권4호
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• pp.401-406
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• 2010

We have measured and analyzed the dark data of two PICNIC IR arrays (P574 and P560) obtained through the Cosmic Infrared Background ExpeRiment (CIBER). First, we identified three types of bad pixels: the cold, the hot, and the transient, which are figured in total as 0.06% for P574 and 0.19% for P560. Then, after the bad pixels were masked, we determined the dark noise to be 20.5 ${\pm}$ 0.05 $e^-$ and 16.1 ${\pm}$ 0.05 $e^-$, and the dark current to be 0.6 ${\pm}$ 0.05 $e^-$/sec and 0.7 ${\pm}$ 0.05 $e^-$/sec for P574 and P560, respectively. Finally, we discussed glitches and readout modes for a future mission.