• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.2
• /
• pp.76.2-76.2
• /
• 2017

We present Subaru Near-Infrared (NIR) photometry for globular clusters (GCs) in the giant elliptical galaxy NGC 4649 (M60) belonging to the Virgo cluster. NIR data are obtained in Ks-band with the Subaru/MOIRCS, and matching HST/ACS optical data available in literature are used to explore the origin of GC color bimodality. A clear bimodal color distribution is observed in the optical color (g-z), in which the ratio between blue and red GCs is 4:6. By contrast, the more metallicity-sensitive optical-NIR colors (g-Ks, z-Ks) show a considerably weakened bimodality in their distributions. The color-color relation of the optical and NIR colors for the GC system shows a nonlinear feature, supporting that the optical color bimodality observed in NGC 4649 GC system is caused by nonlinear color-metallicity relations (CMRs).

• The Bulletin of The Korean Astronomical Society
• /
• v.42 no.1
• /
• pp.53.4-53.4
• /
• 2017

With large-volume surveys becoming the norm, it is increasingly important to accurately model the galaxy-halo connection and being able to create mock universes of galaxies - starting from dark matter halo catalogs - that reproduce with high-fidelity all the characteristics of a given experiment. This step is necessary, in order to safely interpret cosmological data and fully control systematic effects. We are developing a new Python-based tool which integrates several existing packages and allows one to reproduce many of the forms used to describe galaxy-halo models, ranging from halo occupation distribution (HOD) to abundance matching techniques, along with the characteristics of a given survey and the main testable observables. We are making the code parallel for high-performance parallel-architectures.

• The Proceeding of the Korean Institute of Electromagnetic Engineering and Science
• /
• v.5 no.3
• /
• pp.48-58
• /
• 1994

In this paper, a CLPDA (Crossed Log-Periodic Dipole Antenna) for EMI / EMC Measurement is presented, and is analyzed by Combining the moment method and the transmission line theory. The CLPDA has a broaddband characteristic. It is so important to achieve a impedance matching over op- erating frequency range that Twin-boom method is used at feed point. Here, the current distribution, input admittance, radiation pattern and gain are calculated. In practice CLPDA is fabricated. Calculated result for radiation pattern and gain are very closed to measured result.

• Coupled systems mechanics
• /
• v.5 no.4
• /
• pp.371-393
• /
• 2016

We propose a heat jet approach for a two-dimensional square lattice with nearest neighbouring harmonic interaction. First, we design a two-way matching boundary condition that linearly relates the displacement and velocity at atoms near the boundary, and a suitable input in terms of given incoming wave modes. Then a phonon representation for finite temperature lattice motion is adopted. The proposed approach is simple and compact. Numerical tests validate the effectiveness of the boundary condition in reflection suppression for outgoing waves. It maintains target temperature for the lattice, with expected kinetic energy distribution and heat flux. Moreover, its linear nature facilitates reliable finite temperature atomic simulations with a correct description for non-thermal motions.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2001.04b
• /
• pp.735-738
• /
• 2001

한전에서는 판매업무의 혁신을 기하기 위하여 지리정보시스템(GIS)을 운영기반으로 하는 신배전정보 시스템(NDIS : New Distribution Information System) 구축사업을 적극적으로 추진하여 현재 일부 지사 지점에서 시범운영중에 있으며, 향후 전국적인 운영확산이 예정되어 있다. NDIS에서는 국가기본도를 GIS의 기초도면으로 활용하고 있으나 DB구축시 기존 설비도면과의 상대위치오차가 발생되고, 설비가 누락 또는 오분류되어 있는 경우가 있어 이를 보정하는데 많은 노력이 드는 실정이다. 국가기본도 사용을 전제한 때 이러한 문제점은 피할 수 없는 현상이며, 한전에서는 이를 보다 효과적으로 해결하고자 배전설비에서 위치의 기준이 되는 전주를 중심으로 기초도면 변경에 따른 설비도면 보정기법연구와 시스템 개발을 수행하였다. 본고에서는 한전에서의 설비도 위치보정 적용환경과 함께 연구개발된 내용을 소개하고자 한다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.1B
• /
• pp.48-55
• /
• 2000

The design techniques of an asymmetric TEM (ATEM) cell for calibrating E/H filed probes are presented in this paper. The authors describe the techniques to obtain not only the arbitrary frequency and second resonant frequency, but also the test space with $\pm$2dB filed uniformity. We could design an ATEM cell that the measured data, electric filed distribution inside the cell, impedance matching and resonant frequencies, agree with the calculated results.

• Aerospace Engineering and Technology
• /
• v.3 no.1
• /
• pp.257-266
• /
• 2004

A three node triangular element with drilling rotations incorporating improved higher-order zig-zag theory(HZZT) is developed to accurately assess the stress distribution through thickness of the laminated plate and analyze the vibration of pretwisted composite plates with embedded damping layer. Shear force matching conditions are enforced along the interfaces between the embedded damping patch and the border patch. The natural frequencies and model loss factors are calculated for cantilevered pretwisted composite blade with damping core with the present triangular element, and compared to experiments and MSC/NASTRAN using a layered combination of plate and solid elements.

• Journal of the Optical Society of Korea
• /
• v.18 no.5
• /
• pp.485-494
• /
• 2014

A novel antenna with ellipsoid-paraboloid surfaces configuration is designed for matching the incident radial radiation fiber laser distribution for maximum transmission efficiency. The on-axial and off-axial defocus effects on the optical antenna system, resulting in energy loss, are analyzed in detail. Knowledge of the effects of those defocuses on beam divergence, aberration and antenna transmission efficiency is of great importance to the long range communication systems.

• The Bulletin of The Korean Astronomical Society
• /
• v.39 no.1
• /
• pp.47.1-47.1
• /
• 2014

We examine the effect of environment on star formation activity of a sample of galaxy group catalogue given in Tempel et al.(2012) constructed from the Sloan Digital Sky Survey Data Release 8. In order to compare galaxies in different environment, we classify galaxies into two groups: galaxies in low density environment and galaxies in high density environment. After matching colors and apparent magnitudes of the galaxies, we are left with 5912 galaxies in each of the environment category. The fraction of star-forming galaxies in low-density environment is ~34%, higher than ~15% in high-density environment. Star-forming galaxies in low density environment have a higher average SFR value than those in high density environment. The bulge-to-disk ratio for galaxies in two different environment shows bimodal distribution. Regardless of the environment, we find galaxies with high star formation rate despite their red (g-r) color, for which the origin enhancing their star formation rate is investigated.

• Journal of electromagnetic engineering and science
• /
• v.13 no.4
• /
• pp.208-213
• /
• 2013

This paper proposes a tag antenna for radio frequency identification (RFID) food system. The RFID tag antenna is designed and fabricated based on the rectangular loop concept used in the UHF band (Korean and Japanese standards, 916.7-923.5MHz). The proposed tag antenna is composed of a radiation patch, sensor tag chip, temperature sensor, oscillator, and battery. We conjugated matching between the tag antenna and the sensor tag using a U-shaped stub. Details of the proposed tag antenna design and the simulated and measured results are presented and discussed.