• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.615-619
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• 2009

This paper is investigated to variation of wave power generation operation rate, operating capacity and output with the wave conditions represented by wave height-period window. By the use of the long-term wave data from 1979 to 2002 which is provided by Korea Ocean Research & Development Institute(KORDI), we calculated the monthly variation of significant wave height(Hs), zero-up crossing period(Tz) and distribution of wave appearance rate. And using the same wave data, it was charted the Hs-Tz and wave-energy scatter diagrams.

• Journal of Multimedia Information System
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• v.3 no.4
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• pp.161-168
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• 2016

In this paper, a power flow simulator, which visualizes power flow and system configuration, is proposed and implemented. Generally, it is necessary to prepare a text file with power-system descriptions, which is one of the barriers for power-flow simulations. The proposed simulator has a function of automatic generations of IEEE common data format files from user-drawn power-system diagrams. Therefore, it is possible for users to carry out simulations only by drawing power system on display. In addition, the proposed simulator also has a function that power-system diagram is illustrated automatically from an IEEE common data format file. By using this function, it is possible to visualize amounts and directions of power flows on the bus-system diagram, which helps users to comprehend network dynamics intuitively. Because the proposed simulator allows including renewable-resource generators in power systems, it is useful to evaluate the power distribution system. It is shown in this paper that the proposed simulator can make IEEE common data format files correctly and illustrate intuitive power flow.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.48.2-48.2
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• 2014

We study the resolved stellar populations of ESO149-G003, a nearby dwarf irregular galaxy in the vicinity of the Sculptor group. We present F606W-F814W vs. F814W colour-magnitude diagrams (CMDs) obtained from HST/ACS archival data. We analyze the stellar content of ESO149-G003, as well as the spatial distribution of stars selected from stellar isochrone fitting analysis. Distance measurement using the tip of the red giant branch method, age measurement of various populations seen in the CMD, and isochrone fitting result will be shown and discussed.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.3
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• pp.255-261
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• 2015

An analysis of the interleaving effect for the secondary winding distribution of a toroidal transformer is presented in this paper. The equations to calculate the leakage inductance of the toroidal transformer are derived using MMF diagrams for the different secondary winding distributions. The simulation and experimental results are provided to show the validity of the theoretical calculation.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.82.2-82.2
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• 2010

We investigate the distribution of stars along the red giant branch (RGB) in the globular clusters (GCs) NGC 288 and NGC 362 from Caby photometry using the CTIO 4m Blanco telescope. Our color-magnitude diagrams in hk index show that the RGB stars have two distinct subpopulations with different Ca abundances apparently supplied by the Type II supernovae explosions. However, the RGB splits are not shown in the b - y color, as indicated by previous observations. Our stellar population models show that the presence of two distinct RGBs in these GCs can be reproduced if metal-rich second generation stars are also enhanced in helium and younger by 1 ~ 2 Gyrs.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2000.11a
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• pp.31-35
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• 2000

We investigate the groundwater distribution and chemical characteristics for 3 or 5 districts every year and make the hydrogeologic map on a scale of 1:50,000. We draw the hydrogeologic digital map based on "The Handbook for the Drawing and Management of Hydrogeologic Map" which was published by MOCT and KOWACO in 1998. But, the Stiff diagram and well's notation are difficult to be presented in the digital map using the commercial Arcview GIS tools. So we develop the script file with Avenue language to represent them in Arcview GIS tool. At first, we design the database for the chemical analysis result of groundwater and well identification, and make the program code with Avenue language to display them on the digital map. And next we test the usefulness of the program code. As a result, we find that the script file is very useful for drawing the symbols and diagrams in hydrogeologic digital map using ArcView GIS.

• Journal of The Korean Astronomical Society
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• v.13 no.1
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• pp.45-62
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• 1980

Defining a metal parameter $(Sp)_c$, which is related to the morphological parameters of C-M diagrams, we have estimated metal abundances for 97 globular clusters in our Galaxy. A correlation between absolute magnitude of the horizontal branch and metal abundance is derived, which is used for the determining distances to globular clusters whose visual magnitudes of the horizontal branch are known. The space distribution of globular clusters and the chemical evolution of the halo are examined. Our analysis suggests an initial mean gradient of metallicity to be d[Fe/H]/$dr_G$ = -0.06 $kpc^{-1}$ for the halo in galactocentric distance, $r_G$<20 kpc. Our findings also imply a slow collapse of protogalaxy.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.55
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• pp.25-31
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• 2000

To make a better decision about when to shutdown a nuclear power plant, we build a decision model using influence diagrams. We proceed the analysis adopting a bayesian approach. Firstly, an accident arrival rate is assumed to be known and this assumption is relaxed later. We perform our analysis on the cases of exponential time to accidents, and gamma distribution for the arrival rate. An optimal shutdown time is obtained considering the trade-off between the costs incurred by an accident due to late shutdown and the possible loss of revenues due to the early shutdown. We also derive the upper bound of the failure rate where we may operate the plant.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.673-678
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• 2015

Terahertz dual-band frequency selective surface filters made by perforating two different rectangular holes in molybdenum have been designed, fabricated and measured. Physical mechanisms of the dual-band resonant responses are clarified by three differently configured filters and the electric field distribution diagrams. The design process is straightforward and simple according to the physical concept and some formulas. Due to the weak coupling between the two neighboring rectangle holes with different sizes in the unit cell, good dual-band frequency selectivity performance can be easily achieved both in the lower and higher bands by tuning dimensions of the two rectangular holes. Three samples are fabricated, and their dual-band characteristics have been demonstrated by a THz time-domain spectroscopy system. Different from most commonly used metal-dielectric structure or metal-dielectric-metal sandwiched filters, the designed dual-band filters have advantages of easy fabrication and low cost, the encouraging results afforded by these filters could find their applications in dual-band sensors, THz communication systems and other emerging THz technologies.

• Transactions on Electrical and Electronic Materials
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• v.6 no.2
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• pp.39-45
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• 2005

Numerical and visualization procedures are used in a finite difference grid to analyze and better understand the heat transfer in the MEMS based air micro-jet array (MIA) impingement cooling device. The Navier-Stokes (NS) equations with incompressible flow are solved using an implicit procedure. The temperature contour and velocity vector visualization diagrams are used for illustration. The computed temperature distribution at the bottom of the MIA is in good agreement with the experimental measurement data. The parameters are investigated to improve the efficiency of heat transfer in the MIA. The optimum configuration of the MIA is suggested. The present modeling explains the flow phenomenon and yields valuable information to understand the flow and heat transfer in MIA.