• The Bulletin of The Korean Astronomical Society
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• v.24 no.1
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• pp.17-17
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• 1999

• Journal of Satellite, Information and Communications
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• v.8 no.3
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• pp.41-46
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• 2013

In this paper, we present the compatibility study results including the frequency sharing criteria between new allocation to maritime mobile satellite service and Earth exploration satellite service in the 7/8 GHz. The transmitting Earths station of MMSS in the 8025 - 8400 MHz band would make harmful interference to the receiving Earth station of EESS operating in the same frequency band. In order to ensure the compatibility with EESS, the separation distance is provided as a frequency sharing criteria. The republic of Korea has a plan to launch the geostationary satellite around 2017 and EESS Earth station will be operated in 8025 - 8400 MHz band. Therefore, we calculate the interference levels and separation distance using the system parameters of two Earth station systems. As results of the study, the separation distances for LOS path and Non-LOS path due to the geographical characteristics are shown around 471 km and 200 km, respectively.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.654-664
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• 2018

In this paper, this system is operated by PCS that is driven by being synchronized voltage fed inverter and AC source, and in the steady state of power source charge battery connected to DC side with solar cell using a photovoltaic (PV) that it was so called constant voltage charge. it can cause the effect of energy saving of electric power, from 10 to 20%. and through a normal operation of electric energy storage system (EESS). In addition, better output waveform was generated because of pulse width modulation (PWM) method, and it was Proved to test by experiment maintained constant output voltage regardless of AC source disconnection, load variation, and voltage variation of AC power source.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.663-668
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• 2008

Recently, World Radio Conference(WRC)-2007 approved the ultrawide bandwidth of 500 MHz for the use of spaceborne synthetic aperture radar in X-band for the EESS(Earth Exploration Satellite Service) in order to improve the SAR imaging resolution. It is concerned about the interference impact from the spaceborne SAR that may cause to most of ground radars due to the extended ultra wideband. In this paper, in order to predict the interference impact of the ground-based radar from the spaceborne radar, radar interference model is presented using radar characteristic parameters by taking into account the operating environments of the spaceborne and ground based radar in the time, space, and spectrum domains. Using the spaceborne SAR model of TerraSAR-X and ground radar model of meteorological radar recommended by ITU-R, the interference impact was assessed through the computer simulation to see the possible interference impact of the ground based radar operating in the Korean peninsula.

• Progress in Superconductivity and Cryogenics
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• v.16 no.4
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• pp.57-61
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• 2014

Output fluctuation which is generated in wind power farm can hinder stability of total power system. The electric energy storage (EES) reduces unstable output, and superconducting magnetic energy storage (SMES) of various EESs has the proper performance for output compensation of wind power farm since it charges and discharges large scale power quickly with high efficiency. However, because of the change of current within SMES, the electromagnetic losses occur in the process of output compensation. In this paper, the thermal effect of the losses that occur in SMES system while compensating in wind power farm is analyzed. The output analysis of wind power farm is processed by numerical analysis, and the losses of SMES system is analyzed by 3D finite element analysis (FEA) simulation tool.

• Journal of the East Asian Society of Dietary Life
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• v.25 no.6
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• pp.990-998
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• 2015

The aim of this study was to examine the cytotoxicity and potential inhibitory effects from four types of edible domestic brown seaweeds, Undaria pinnatifida (UP), Laminaria japonica (LJ), Sargassum fulvellum (SF), and Hizikia fusiforme (HF), on preadipocyte differentiation in 3T3-L1 cell line. Water and ethanol extracts from the four types of seaweeds were prepared and tested for cell viability in the 3T3-L1 cell line by using MTT assay. In addition, various doses of the water extract of seaweeds (WES) and ethanol extract of seaweeds (EES) were treated at the beginning of 3T3-L1 differentiation and continued until the cells were fully differentiated to adipocytes. Oil Red-O staining was performed to determine the potential cell differentiation inhibitory effects of the WES and EES by measuring the levels of lipid droplet accumulation in 3T3-L1 adipocytes. $PPAR{\gamma}$ mRNA expression levels were significantly reduced by WESs of UP, LJ, and HF as well as EESs of LJ and HF. As a result, we observed the superior cell differentiation inhibitory effects of WES compared to that of EES in a dose-dependent manner without any significant cytotoxicity in mouse adipocytes.

• Journal of Korea Game Society
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• v.4 no.1
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• pp.26-33
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• 2004

OlineGame Player suffers very big impact in environment of game World. Therefore, physical environment that is embodied to Gameworld is truth and immersion important element that experience to Player. Also, Game-System that embodied physical environment influences in Game Play can give more game player truth and immersion. I mainly MMORPG that is serviced present in this study investigated. 'What earth habitat factor was embodied and What influence does embodied earth habit at factor exert on game play'. I searched what problem is to design game system that do earth environment simulation. And I asserted development of environment information system to approach game system that do earth environment simulation by easier method. Environment information system is system that process status information of stand-by status, wind, wind speed, topography etc.. of game World.