• Current Industrial and Technological Trends in Aerospace
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• v.9 no.1
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• pp.3-14
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• 2011

The current space activities are soaring ever since the first human flight to outer space 50 years ago and the first satellite launch 54 years ago. 74 space launch vehicles were launched in 2010, up from average 66 yearly in 2000s, and 900 operational satellites are currently in orbit around Earth. Space has become a worthwhile investment for governments as space assets become vital to national social, economic, and technological development as well as contributing their national defense and security program. The world governments' investments on space programs have reached a historical peak of $71.5 billion in 2010. However, the growth of government funding for space has slowed down posting only a 2% growth rate since 2009 while 9 % compound annual growth rate experienced by world's space expenditures between 2004 and 2009. Korea invested $158 million in 2011, experienced strong decrease with a 16% compound annual growth rate since 2008. In this paper the current statuses of world governments' funding for space program and space market were presented and the current issues on the Korean space budget policy were reviewed.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2225-2229
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• 2010

In this study, we have investigated the effects of space charge on the conduction current with the variation of applied time of electric field in polymer insulators. We had also improved the PEA method, and then we could measure a simultaneously the space charge and the conduction current in insulators under the DC electric field. From this experiment, we have known the variation of conduction current due to the existence of space charge in XLPE1 and XLPE2.

• Journal of Astronomy and Space Sciences
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• v.32 no.4
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• pp.427-434
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• 2015

Coronal Mass Ejections (CME), which originate from active regions of the Sun's surface, e.g., sunspots, result in geomagnetic storms on Earth. The variation of the Earth's geomagnetic field during such storms induces surface currents that could cause breakdowns in electricity power grids. Hence, it is essential to both monitor Geomagnetically Induced Currents (GICs) in real time and analyze previous GIC data. In 2012, in order to monitor the variation of GICs, the Korean Space Weather Center (KSWC) installed an induced current measurement system at SINGAPYEONG Substation, which is equipped with 765 kV extra-high-voltage transformers. Furthermore, in 2014, two induced current measurement systems were installed on the 345 kV high-voltage transformers at the MIGEUM and SINPOCHEON substations. This paper reports the installation process of the induced current measurement systems at these three substations. Furthermore, it presents the results of both an analysis performed using GIC data measured at the SINGAPYEONG Substation during periods of geomagnetic storms from July 2013 through April 2015 and the comparison between the obtained GIC data and magnetic field variation (dH/dt) data measured at the Icheon geomagnetic observatory.

• Current Industrial and Technological Trends in Aerospace
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• v.7 no.1
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• pp.3-10
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• 2009

In this paper the current statuses of world governments' funding for space program and space market were presented. Since 2001, governments' expenditures for space program have experienced strong growth, and are at a historical high, estimated $62.1 billion in 2008, as compared to $30-35 billion in 1990s. Following a peak growth of 9% in 2008, government budgets for space program are expected to continue their growing trend but at a slower pace during next five years, with 4.5%. Also world space market revenue reached a historical high $123 billion in 2007 with 11.5% annual growth rate during 2002-2007. In this paper the Korean government's budget and Korean space market revenue were presented too, and compared to those worldwide.

• Current Industrial and Technological Trends in Aerospace
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• v.8 no.1
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• pp.3-11
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• 2010

Despite the global economic recession, the space market has reached a historical peak of $160.9 billion in 2009, a 11 % growth compared to the previous year. The world governments' investments on space programs totaled $68 billion in 2009, 11% growth compared to 2008. However, Korea invested $217 million in 2009, 24% decrease compared to 2008. The completion of the 'Naro' rocket project has an impact regard to the budget cut. The Korean space market decreased 3% to $789 million due to the decrease of the export of satellite phone by economic recession. In this paper the current statuses of world governments' funding for space program and space market were presented and the current issues on the Korean space budget policy were reviewed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.117-118
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• 2014

The unfloored space and floor is one of characteristic of traditional house in Korea. This space is used to connecting passage between room or entrance of house. Currently, according to decline of heat insulation property thereby becoming decrepit house, native is repairing it for block external environment such as rain, wind and so on. But, variety problem is happening from wrong repair. This object of this study is current status and analysis on problem of unfloored space and floor repair. As a result, current status of repair is classified repair type, installation position and using form. And position of problem is confirmed connection between original house and extend space.

• Proceedings of the KIEE Conference
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• 1995.07a
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• pp.357-359
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• 1995

In this paper, vector control of induction motor drives using space current vector PWM is presented. The scheme gives advantages, besides robustness to inverter arm-shoot, sinusoidal input current and voltage for induction motors. In addition, space vector PWM for CSI produces faster transient response than conventional pattern PWM. Also, a modulation index control is proposed.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.51 no.7
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• pp.322-327
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• 2002

Temperature-dependent current-voltage characteristics of organic light-emitting diodes(OLEDs) were studied in a device structure of ITO/TPD/Alq$_3$/Al to understand conduction mechanism. The current-voltage characteristics were measured in the temperature range of 8K ~ 300K. We analyzed an electrical conduction mechanism of the OLEDS using space-charge-limited current(SCLC) and Fowler-Nordheim tunneling. In the temperature range above 150k, the conduction mechanism could be explained by space charge limited current from the inversely proportional temperature dependence of exponent m. The characteristic trap energy is found to be about 0.15ev. At low temperatures below 150k, the Fowler-Nordheim tunneling conduction mechanism is dominant. We have obtained a zero field barrier height to be about 0.6~0.8eV.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1992.11a
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• pp.37-40
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• 1992

This paper examined the existance behavior of charged particles by measuring polarity inversion current Thermal Stimulate Current (TSC) and analysed appearance mechanism of polarity inversion current Peak and Also investigated relation between ionic space charge format ion and dielectric breakdown by measuring D.C breakdown impulse breakdown D.C - impulse superposition as a sample of FET. As a result. lie found that dielectric breakdown is likely to happen due to ionic space charge at the transient state when applied polarity inversion voltage and that charged partion of TSE Peak at the high temperature was the same as that of polarity inversion current. Also there was no effect on ionic space charge about the dielectric breakdown in stationary state when applied D.C voltage.

• Publications of The Korean Astronomical Society
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• v.27 no.4
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• pp.105-109
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• 2012

The current status of the AKARI-FIS Point Source Catalogue is reported. The first version of the Bright Source Catalogue has been in public since March 2010 and used extensively in the various fields in astronomy. The second version of the Bright Source Catalogue and the first version of the Faint Source Catalogue are currently under development. The revised Bright Source Catalogue is expected to have improved completeness, reliability, and accuracy compared to the current version. The Faint Source Catalogue will have a scan-density dependent detection limit and will enable much deeper exploration of the sky especially in the high-ecliptic latitude regions. Both catalogues will be available in a year time scale.