• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.257-261
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• 2017

We built a $8{\mu}m$ selected sample of galaxies in the NEP-AKARI field by defining 4 redshift bins with the four AKARI bands at 11, 15, 18 and 24 microns (0.15 < z < 0.49, 0.75 < z < 1.34, 1.34 < z < 1.7 and 1.7 < z < 2.05). Our sample contains 4079 sources, 599 are securely detected with Herschel/PACS. Also adding ultraviolet (UV) data from GALEX, we fit the spectral energy distributions using the physically motivated code CIGALE to extract the star formation rate, stellar mass, dust attenuation and the AGN contribution to the total infrared luminosity ($L_{IR}$). We discuss the impact of the adopted attenuation curve and that of the wavelength coverage to estimate these physical parameters. We focus on galaxies with a luminosity close the characteristic $L^*_{IR}$ in the different redshift bins to study the evolution with redshift of the dust attenuation in these galaxies.

• Journal of Environmental Health Sciences
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• v.43 no.4
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• pp.298-306
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• 2017

Objectives: Since 1998, the Korea National Health and Nutrition Examination Survey (KNHANES) has been conducted in order to investigate the health and nutritional status of Koreans. The food intake data of individuals in the KNHANES has also been utilized as source dataset for risk assessment of chemicals via food. To improve the reliability of intake estimation and prevent missing data for less-responded foods, the structure of integrated long-standing datasets is significant. However, it is difficult to merge multi-year survey datasets due to ineffective cleaning processes for handling extensive numbers of codes for each food item along with changes in dietary habits over time. Therefore, this study aims at 1) cleaning the process of abnormal data 2) generation of integrated long-standing raw data, and 3) contributing to the production of consistent dietary exposure factors. Methods: Codebooks, the guideline book, and raw intake data from KNHANES V and VI were used for analysis. The violation of the primary key constraint and the $1^{st}-3rd$ normal form in relational database theory were tested for the codebook and the structure of the raw data, respectively. Afterwards, the cleaning process was executed for the raw data by using these integrated codes. Results: Duplication of key records and abnormality in table structures were observed. However, after adjusting according to the suggested method above, the codes were corrected and integrated codes were newly created. Finally, we were able to clean the raw data provided by respondents to the KNHANES survey. Conclusion: The results of this study will contribute to the integration of the multi-year datasets and help improve the data production system by clarifying, testing, and verifying the primary key, integrity of the code, and primitive data structure according to the database normalization theory in the national health data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3533-3539
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• 2009

An air conditioner impeller has been used to suck the warm air and to blow the chilled air by the centrifugal force induced from the rotation of it. To check the possibility of the fracture due to resonance, both numerical and experimental approach was carried out. For the structural analysis, the commercial code ANSYS based on the Finite Element Method was employed. The possibility of the fracture is the resonance between the natural frequency of impeller and characteristic frequency due to the aerodynamic forces. Experiment was carried out to see the natural frequency and numerical analysis based on the Vortex Element Method is performed to get the characteristic frequency. Comparing the natural frequencies that are calculated as described, we believe that resonance occurs.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.92-99
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• 2002

This work investigated the optimal condition for an uniform deposition growth rate in the vertical cylindric CVD chamber. Heat transfer, surface chemical reaction and mass diffusion in the flow field of CVD chamber h,id been computed using Fluent v5.3 code. A SIMPLE based finite Volume Method (FVM) was adopted to solve the fully elliptic equations for momentum, temperature and concentration of a chemical species. The numerical analysis results show good agreements with the measurements obtained by N. Yoshikawa. The results obtained by the numerical analysis showed that the film growth rate in the center of a susceptor is increasing, as the inner flow approaches to the forced convection. To the contrast, as it approaches to the natural convection, that in the outside of a susceptor is increasing. As the Reynolds number increases, the uniformity may not hold due to the larger temperature gradient at a susceptor surface. Therefore, when the temperature gradient on the surface of a susceptor is zero, the film growth rate becomes uniform on most surface.

• Journal of Astronomy and Space Sciences
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• v.32 no.2
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• pp.127-136
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• 2015

We present a by-product of our long term photometric monitoring of cataclysmic variables. 2MASS J18024395 +4003309 = VSX J180243.9 +400331 was discovered in the field of the intermediate polar V1323 Her observed using the Korean 1-m telescope located at Mt. Lemmon, USA. An analysis of the two-color VR CCD observations of this variable covers all the phase intervals for the first time. The light curves show this object can be classified as an Algol-type variable with tidally distorted components, and an asymmetry of the maxima (the O'Connell effect). The periodogram analysis confirms the cycle numbering of Andronov et al. (2012) and for the initial approximation, the ephemeris is used as follows: Min I. BJD = 2456074.4904+0.3348837E. For phenomenological modeling, we used the trigonometric polynomial approximation of statistically optimal degree, and a recent method "NAV" ("New Algol Variable") using local specific shapes for the eclipse. Methodological aspects and estimates of the physical parameters based on analysis of phenomenological parameters are presented. As results of our phenomenological model, we obtained for the inclination $i=90^{\circ}$, $M_1=0.745M_{\odot}$, $M_2=0.854M_{\odot}$, $M=M_1+M_2=1.599M_{\odot}$, the orbital separation $a=1.65{\cdot}10^9m=2.37R_{\odot}$ and relative radii $r_1=R_1/a=0.314$ and $r_2=R_2/a=0.360$. These estimates may be used as preliminary starting values for further modeling using extended physical models based on the Wilson & Devinney (1971) code and it's extensions

• Korean Journal of Microbiology
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• v.43 no.4
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• pp.285-291
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• 2007

According to the Baltimore Scheme, viruses are classified into 6 main classes based on their replication and coding strategies. Except for some small DNA viruses, most viruses code for their own polymerases: DNA-dependent DNA, RNA-dependent RNA and RNA-dependent DNA polymerases, all of which contain 4 common motifs. We undertook a phylogenetic study to establish the relationship between the Baltimore Scheme and viral polymerases. Amino acid sequence data sets of viral polymerases were taken from NCBI GenBank, and a multiple alignment was performed with CLUSTAL X program. Phylogenetic trees of viral polymerases constructed from the distance matrices were generally consistent with Baltimore Scheme with some minor exceptions. Interestingly, negative RNA viruses (Class V) could be further divided into 2 subgroups with segmented and non-segmented genomes. Thus, Baltimore Scheme for viral taxonomy could be supported by phylogenetic analysis based on the amino acid sequences of viral polymerases.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.7
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• pp.391-399
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• 2018

The site coefficients in the common requirements for seismic design codes, which were promulgated in 2017, were reevaluated and the standard design spectrum for soil sites were newly proposed in order to ensure the consistency of the standard design spectra for rock and soil sites specified in the common requirements. Using the 55 ground motions from domestic and overseas intraplate earthquakes, which were used to derive the standard design spectrum for rock sites, as rock outcropping motions, site response analyses of Korean soil were performed and its ground-motion-amplification was characterized. Then, the site coefficients for soil sites were reevaluated. Compared with the existing site coefficients, the newly proposed short-period site coefficient $F_a$ increased and the long-period site coefficient $F_v$ decreased overall. A new standard design spectrum for soil sites was proposed using the reevaluated site coefficients. When compared with the existing design spectrum, it could be seen that the proposed site coefficients and the standard design spectrum for soil sites were reasonably derived. They reflected the short-period characteristics of earthquake and soil in Korea.

• Journal of the Korean Institute of Navigation
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• v.23 no.2
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• pp.29-42
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• 1999

An accurate method of estimating ship maneuverability needs to be developed to evaluate precisely and improve the maneuverability of ships according to the water depth. In order to estimate maneuverability by a mathematical model. The hydrodynamic forces acting on a ship hull and the flow field around the ship in maneuvering motion need to be estimated. The ship speed new the berth is very low and the fluid flow around a ship hull is unsteady. So, the transient fluid motion should be considered to estimate the drag force acting on the ship hull. In the low speed and short time lateral motion, the vorticity is created by the body and grow up in the acceleration stage and the velocity induced by the vorticity affect to the body in deceleration stage. For this kind of problem, CFD is considered as a goof tool to understand the phenomena. In this paper, the 2D CFD code is used for basic consideration of the phenomena to solve the flow in the cross section of the ship considering the ship is slender and the water depth is large enough. The flow fields Added and hydrodynamic forces for the some prescribed motions are computed and compared with the preliminary experiment results. The comparison of the force with measurement is shown a fairly good agreement in tendency. The 3D Potential Calculation based on the Hess & Smith Theory is employed to predict the surge, sway added mass and yaw added moment of inertia of hydrodynamic coefficients for M/V ESSO OSAKA according to the water depth. The results are also compared with experimental data. Finally, the sway added mass of hydrodynamic coefficients for T/S HANNARA is suggested in each water depth.

• Progress in Medical Physics
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• v.16 no.2
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• pp.97-103
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• 2005

The energy spectra and dose calculations were performed for secondary neutrons from a 24 MV LINAC using MCNPX code (V2, 4, 0). The energy spectra for neutrons and photons emitted from the LINAC head, and absorbed dose to water were calculated in water phantom. The absorbed doses calculated with Monte Carlo were $0.66\~0.35$ mGy/photon Gy at the surface to d=5 cm, and calculated with interaction data was 0.52 mGy/photon Gy at the depth of electron equilibrium in water. We have shown that this work can be applied to dose estimation of neutrons from high energy LINAC through the comparison of our results with other results.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.5
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• pp.75-84
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• 2010

The aim of this paper is to design the blank shape of SPFH 590 high strength steel for stamping of the center hinge of automotive via numerical analyses and experiments for multi-stages transfer forming process. Three-dimensional elasto-plastic finite element analyses for the transfer forming process with six stages were performed using a commercial code AUTOFORM V4.2. The influence of the blank shape on the formability and the shape conformity were quantitatively examined through the FE analyses. From the results of the FE analysis, a feasible shape of the blank and the forming load were estimated. Stamping experiments were carried out using the proposed blank shape. The results of experiments were shown that the center hinge parts with the desired shapes can be manufactured successfully as the proposed blank shape is used. Through the comparison of the results of the experiments with those of the analyses, it was shown that the estimation of blank shape using the FE analysis is a proper methodology to create a feasible shape of the blank for the center hinge of automotive.