• Journal of Power System Engineering
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• v.12 no.3
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• pp.60-65
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• 2008

This study aims at investigating the wear properties of thermally sprayed $Al/Al_2O_3$ metal matrix composite(MMC) coating against different counterparts. $Al/Al_2O_3$ MMC coatings were fabricated using a flame spray system on an Al 6061 substrate. Dry sliding wear tests were performed using the sliding speeds of 0.2m/s and the applied loads of 1 and 2 N. AISI 52100, $Al_2O_3$, $Si_3N_4\;and\;ZrO_2$ balls(diameter: 8mm) were used as counterpart materials. Wear properties of $Al/Al_2O_3$ MMC coatings were analyzed using a scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDX). It was revealed that wear properties of $Al/Al_2O_3$ composite coatings were much influenced by counterpart materials. In the case of AISI 52100 used as counterparts, the wear rate of composites coating layer increased according to the increase of the applied load. On the contrary, in the case of ceramics used as counterparts, the wear rate of composites coating layer decreased according to the increase of the applied load.

• Korean Journal of Human Ecology
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• v.21 no.6
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• pp.1145-1160
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• 2012

This study empirically compared generational differences in responses between baby boomers, Generation X, and Generation Y groups as measured by key variables related to advertisement. The respondents in this study were consumers throughout Korea, with 914 survey questionnaires used for the final analyses. Eight of the original 10 hypotheses were validated and two were rejected. Both baby boomer consumers and Generation Y consumers showed more positive responses to affective advertisements than their Generation X counterparts. Generation Y consumers showed more positive attitudes towards humorous advertisements than their baby boomer and Generation X counterparts. The effect of advertising models on the evaluation of advertisements was greater among Generation Y consumers than their Generation X counterparts. Generation Y consumers showed more positive attitudes towards storytelling-type marketing than their baby boomer and Generation X counterparts. Baby boomer consumers showed more positive attitudes towards symbolic advertisements than their Generation X and Generation Y counterparts. Generation X consumers showed more positive attitudes towards functional advertisements than the baby boomer and Generation Y groups. There were significant differences in attitudes towards two types (symbolic and functional) of advertisements in both baby boomer consumers and Generation X consumers.

• The Journal of Korean Medicine
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• v.33 no.2
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• pp.56-63
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• 2012

Objectives: To undertake manpower-related improvements based on a comparison between specialists in the traditional Korean medicine hospitals(TKMH) and their counterparts in Western medicine Methods: A survey of the TKMH based on questionnaire sheets dispatched to them by mail(57 of 142 responded) in the June December, 2008 period, and on almanac statistics provided by the Ministry for Health, Welfare and Family Affairs of Korean Government. Results: Overall, the workforce engaged in the traditional Korean medicine hospitals comprises traditional Korean medical doctors(28%), nurses(23%), administrative staffs(19%), assistant nurses(9%), medical record keepers(2%), nutritionists(2%), herbal pharmacists(1%), and others(16%). Each hospital has 16.5 traditional Korean medical doctors on average, which can be broken down into 6.2 specialists, 1.3 generalists, and 9.3 residents/interns. Only 10.7% of whole of traditional Korean medical doctors work in the hospitals, compared to 54.5% of Western medicine doctors. The ratio of traditional Korean medical doctors to the entirety of employees in the TKMH is 2.5 times higher than their Western medicine counterparts, while the ratio of medical technicians to the entire employees in the TKMH is 20 times lower than in the Western medicine counterparts. Conclusions: To provide more qualified medical service in the TKMH, they will be required to increase the proportion of non medical doctor employees, like Western medicine counterparts.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.1
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• pp.53.3-54
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• 2021

We present optical follow-up observation results of three binary black hole merger (BBH) events, GW190408 181802, GW190412, and GW190503 185404, which were detected by the Advanced Ligo and Virgo gravitational wave (GW) detectors. Electromagnetic (EM) counterparts are generally not expected for BBH merger events, however, some theoretical models suggest that EM counterparts of BBH can possibly arise in special environments. To identify EM counterparts of the three BBH merger events, we observed high-credibility regions of the sky with telescopes of the Gravitational-wave EM Counterpart Korean Observatory (GECKO), including the Korea Microlensing Telescope Network (KMTNet). Our observation started as soon as 100 minutes after the GW event alert and covered roughly 29 - 63 deg2 for each event with a depth of 22.5 mag in R-band within hours of observation. No plausible EM counterparts were found for these events. Our result gives a great promise for the GECKO facilities to find EM counterparts within few hours from GW detection in future GW observation runs.

• Journal of Power System Engineering
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• v.11 no.4
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• pp.92-97
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• 2007

This study aims at investigating the wear behavior of thermally sprayed Ni-based self-flux alloy coatings against different counterparts. Ni-based self-flux alloy powders were flame-sprayed onto a carbon steel substrate and then heat-treated at temperature of $1000^{\circ}C$. Dry sliding wear tests were performed using the sliding speeds of 0.2 and 0.8 m/s and the applied loads of 5 and 20 N. AISI 52100, $Al_2O_3$, $Si_3N_4$ and $ZrO_2$ balls were used as counterpart materials. Wear behavior of Ni-based self-flux alloy coatings against different counterparts were studied using a scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDX). It was revealed that wear behavior of Ni-based self-flux alloy coatings were much influenced by counterpart materials.

• Journal of The Korean Astronomical Society
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• v.47 no.5
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• pp.163-166
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• 2014

In order to identify peculiar X-ray sources, we select 442 sources with no counterparts in other wavelength bands (as of the year 1999) from the ROSAT All-Sky Survey Bright Source Catalog. We cross-correlate this initial list with the NASA/IPAC Extragalactic Database, the USNO and WISE catalogs, and the HEASARC XRAY Master Catalog. Eventually, we are left with four unidentified sources with no counterparts in other wavelength bands. We present these four sources and their X-ray properties in this paper.

• The Bulletin of The Korean Astronomical Society
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• v.45 no.1
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• pp.35.2-35.2
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• 2020

Submillimeter galaxies (SMGs) have played an important role in the understanding of galaxy evolution and cosmic star formation history at high redshift because they are known as being located at z ~ 2 and harbor a vigorous star formation. Therefore studying properties of SMGs can lead us to understand evolution of massive and actively star forming galaxies and distribution of cosmic star formation density. Recently we detected 548 SMGs near North Ecliptic Pole with JCMT/SCUBA-2 from the JCMT large program covering about 2 deg2 so far. To derive their physical parameters, we compiled a multi-wavelength photometry ranging from optical (0.3 ㎛) to submillimeter (850 ㎛) by cross-identifying counterparts at different wavelengths. In order to find counterparts, we used either VLA-1.4 GHz image and/or Spitzer/IRAC 3.6 ㎛, 4.5 ㎛ image. The number of SMGs with relatively robust counterparts is 349. In this talk, we present photometric redshifts, stellar mass, star formation rates, total infrared luminosity, and AGN fraction of these 349 SMGs derived through SED fitting analysis.

• Journal of Families and Better Life
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• v.30 no.4
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• pp.119-132
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• 2012

The purpose of this study was to investigate the differences in time use between Korean and American high school students. The data sources were the '2009 Time Use Survey' conducted by Korea National Statistical Office and the '2009 ATUS (American Time Use Survey)' conducted by Labor Statistics Division in the U.S.. 1,734 Korean diaries (1,311 on weekdays and 423 on Sundays) and 321 American diaries (208 on weekdays and 113 on Sundays) from high school students of 15 to 18 years of age were analyzed. Descriptive statistics and t-test were used for the statistical analysis. The time use patterns of Korean students on weekdays and Sundays were different than those of their American counterparts. On weekdays and Sundays, the sleeping time of Korean students was 2 hours less than the time of their American counterparts. Koreans studied more, nearly double the time of their American counterparts on weekdays and five times more on Sundays. The study-oriented time allocation of Korean students resulted in less leisure time than the American students. Korean students spent their leisure time of more than 30 minutes participating in social activities, media, and hobbies, and their time allocation to volunteer work and religious activities were nil. On Sundays, the time for studying by Korean students was more than five times longer than that spending by their American counterparts. Koreans used their leisure time of 6 hours and 47 minutes mainly for media, hobbies and social activities. The participation rate of volunteering by Korean students was only 0.5%, though it was 31.0% for the Americans. For a study-life balance for Korean students, it was recommended that trends toward time management and social policy should increase the time allocation to sleeping, housework, work, sports, and volunteering and decrease the time use in studying and hobbies.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.3
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• pp.140-148
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• 2012

Aeronautical lights, which are internationally standardized sequence of colors and placements, are aeronautic safety devices that provide visual information to pilots by continuously adjusting their light intensity to appropriate level. In this paper, we consider the development testing for in pavement LED aeronautical light system such as taxiway centerline, stop line and temporary stop line. The test results of LED sourced lights have shown a drastic improvement in power consumption levels and cost efficiency compared to their halogen sourced counterparts The LED light used only 42.7% as much power as their halogen sourced counterparts. Taking installation costs into account, LED will cost only 58% of its halogen counterparts. These results suggest that developing the LED sourced aeronautical light would result in globally competitive products thar guarantees satisfaction to their consumers, and that both cost effective and energy efficient.

• Korean Journal of Applied Biomechanics
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• v.15 no.1
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• pp.111-125
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• 2005

This study was intended to assist athletes in having a technical understanding of the Yega motion and provide basic material for improving their competitive ability by analyzing the kinematic variable of the Yega motion during the competition of the uneven parallel bar of female gymnastics. For this purpose, the game of female gymnastics participating in the uneven parallel bar game was personally videotaped using the DLT(direct linear transformation) method. An attempt was made to make a comparative analysis of the Yega motion by dividing the final first to third places into the upper group('A' group) and the sixth to eighth places into the lower group('B' group). Based on the results of actual analysis on the scenes of actual game, the following conclusion was concluded: 1. Athletes in the 'A' group showed the shorter required time on the flight phase(P3) than counterparts in the 'B' group. 2. Athletes in the 'A' group showed the little width in the horizontal displacement of the center of gravity than counterparts in the 'B' group. But athletes in the 'A' group exhibited the somewhat greater relative vertical height of the center of the body. 3. Athletes in the 'A' group showed the greater resultant velocity at the lowest point of the center of the body(E2) and at the point in time of release(E3) compared to counterparts in the 'B' group.