• The Korean Journal of Applied Statistics
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• v.18 no.3
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• pp.627-637
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• 2005

Small area estimation has been studied using various methods such as direct, indirect, synthetic and based on regression or time series model . In this paper we investigate a motel-based small area estimation which takes into account the spare time autoregressive model. The Economic Active Population Surveys in 2001 are used for analysis and the results from space-time autoregressive(STAR) and simultaneous autoregressive(SAR) model are compared with using MSE, MAE and MB.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.135-145
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• 2020

Infections caused by Trichomonas vaginalis in humans are one of the main public health problems caused by sexually transmitted diseases. Objective of this study was to evaluate potential biological activity of the medicinal plant Argemone mexicana (Mexican poppy) on T. vaginalis. Methanolic extracts of the stems and leaves of A. mexicana, and different fractions were prepared with solvents of different polarities. The extracts and functional groups were detected containing sterols, triterpenes, quinones, flavonoids and, alkaloids. Extracts from both the stems and leaves of A. mexicana inhibited the growth of T. vaginalis with half-maximal inhibitory concentration value of 70.6 and 67.2 ㎍/ml, respectively. In the active fractions, the most abundant compounds were berberine and jatrorrhizine, with presumed antiparasitic activity.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.2
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• pp.35.3-36
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• 2018

One of the most prevalent knowledge about disk galaxies, which dominate the population of the local Universe, is that they consist of stellar structures with different kinematics, such as thin disk, bulge, and halo. Therefore, investigating when and how these components develop in a galaxy is the key to understanding the evolution of galaxies. Using the NewHorizon simulation, we can resolve the detailed structures of galaxies, in the field environment, from the early Universe where star formation and mergers were most active. We first decompose stellar particles in a galaxy into a disk and a dispersion-dominated, spheroidal, component based on their orbits and then see how these components evolve in terms of mass and structure. At high redshift z~3, galaxies are mostly dispersion-dominated as stars are formed misaligned with the galactic rotational axis. At z=1~2, massive galaxies start to dominantly form disk stars, while less massive galaxies do much later. Furthermore, massive galaxies are forming thinner and larger disks with time, and the preexistent disks are heated or even disrupted to become a part of dispersion-dominated component. Thus, the mass growth of spheroidal components at later epochs is dominated by disrupted stars with disk origins and accreted stars at large radii.

• New & Renewable Energy
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• v.18 no.3
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• pp.72-84
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• 2022

As the threat of climate change escalates, 'net-zero' has become a priority for the international community, and the use of new and renewable energy sources is expected to play a significant role in reaching international carbon neutrality. Here, we evaluate technological competitiveness in terms of implementation and technology by analyzing scientific literature and patents in the new and renewable energy fields of five major countries. For the past 10 years (2009-2019), the most active areas of new and renewable energy research and development have been solar power, wind power, waste, and fuel cells. China is the forerunner in implementation, whereas the United States has the most advanced technology. Portfolio analysis revealed that Korea's fuel cell, the United States' bioenergy, China's waste, Japan's solar and fuel cell, and the European Union's wind power have shown to be in Star Field respectively. Technological competitiveness analysis found that Korea is lagging behind other countries in the new and renewable energy sector, and needs to set a new direction for future carbon-neutral research and development, investment, and policy.

• Journal of Korean Library and Information Science Society
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• v.50 no.4
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• pp.429-467
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• 2019

Various digital literacy and critical competencies are crucial for success in the information and media-rich 21st century game of life. This study explores and describes the digital literacy practices of role-players in WildStar, a science fantasy Massively Multiplayer Online Role Playing Game (MMORPG). Active role-players create and participate in group-driven interactive stories while in-character. A hybrid ethnographic method integrating overt participant observation and engagement, collection of community artifacts across multiple sites (such as wikis, discussion boards, and social media), and semi-structured interviews was employed to understand how role-players seek, use, evaluate, and manage information, media, and technology. Role-players used various media and technologies to supplement, simplify, and make role-playing more immersive. The relative digital literacy skill levels of individuals varied, leading role-players to leverage the skills of more proficient or experienced community members. Given the broad appeal of online games and educational benefits of role-playing, implications and applications for digital literacy skills instruction and library programming are also discussed.

• Journal of Astronomy and Space Sciences
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• v.29 no.2
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• pp.151-161
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• 2012

An intensive analysis of 148 timings of V700 Cyg was performed, including our new timings and 59 timings calculated from the super wide angle search for planets (SWASP) observations, and the dynamical evidence of the W UMa W subtype binary was examined. It was found that the orbital period of the system has varied over approximately $66^y$ in two complicated cyclical components superposed on a weak upward parabolic path. The orbital period secularly increased at a rate of $+8.7({\pm}3.4){\times}10^{-9}$ day/year, which is one order of magnitude lower than those obtained by previous investigators. The small secular period increase is interpreted as a combination of both angular momentum loss (due to magnetic braking) and mass-transfer from the less massive component to the more massive component. One cyclical component had a $20.^y3$ period with an amplitude of $0.^d0037$, and the other had a $62.^y8$ period with an amplitude of $0.^d0258$. The components had an approximate 1:3 relation between their periods and a 1:7 ratio between their amplitudes. Two plausible mechanisms (i.e., the light-time effects [LTEs] caused by the presence of additional bodies and the Applegate model) were considered as possible explanations for the cyclical components. Based on the LTE interpretation, the minimum masses of 0.29 $M_{\odot}$ for the shorter period and 0.50 $M_{\odot}$ for the longer one were calculated. The total light contributions were within 5%, which was in agreement with the 3% third-light obtained from the light curve synthesis performed by Yang & Dai (2009). The Applegate model parameters show that the root mean square luminosity variations (relative to the luminosities of the eclipsing components) are 3 times smaller than the nominal value (${\Delta}L/L_{p,s}{\approx}0.1$), indicating that the variations are hardly detectable from the light curves. Presently, the LTE interpretation (due to the third and fourth stars) is preferred as the possible cause of the two cycling period changes. A possible evolutionary implication for the V700 Cyg system is discussed.

• The Korean Journal of Franchise Management
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• v.12 no.3
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• pp.35-46
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• 2021

Purpose: The hotel industry needs a leader who can actively demonstrate leadership to respond to and accept changes in the organization in a highly competitive and fast-changing environment. Therefore, the role of leaders who instill clear vision and goals of the organization in their members, listen to their opinions, and empathize is paramount. Leaders should encourage successful organizational activities based on active participation by employees and create the best environment for working with a sense of mission and responsibility. This study aims to identify the relationship between empathy leadership and job engagement as a result variable of team cohesion in the hotel culinary department and conduct empirical studies on the role of empathy leadership and job engagement. Research design, data, and methodology: The data were collected from employees who work in culinary department at a five-star franchise hotel located in the Seoul metropolitan area. Because it is difficult to conduct a survey through face-to-face contact with employees due to the COVID-19 pandemic, the online survey was conducted from February 1 to February 28, 2020. A total of 330 questionnaires through online were distributed and 268 employees completed the survey, yielding a response rate of 81%. Of the 268 returned responses, 27 responses were not usable due to missing information. Thus, a total of 241 responses were used for analysis. Results: The study results are as follows. First, it has been shown that the empathy leadership of culinary department in hotel companies has a significant positive impact on the job engagement. Second, it has been shown that job engagement has a significant positive effect on members' team cohesiveness. Third, empathy leadership of hotel companies' culinary department has a significant positive impact on members' team cohesiveness. Fourth, job engagement has a significant positive (+) mediating effect in the relationship between empathy leadership and team cohesiveness in culinary department. Conclusion: This study supports the theory that an emotional and empathic leader's behavior or ability can change the effectiveness or atmosphere of a rapidly changing hotel culinary team organization by presenting a research model on the effect of empathic leadership on job engagement and team cohesiveness. And hotel chefs should be more aware of the importance of empathic leadership and make them a human resource of the organization through formal and informal communication with culinary employees.

• The Bulletin of The Korean Astronomical Society
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• v.44 no.1
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• pp.42.1-42.1
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• 2019

We observed 80 dense cores ($N(H_2)$ > $10^{22}cm^{-2}$) in the Orion molecular cloud complex which contains the Orion A (39 cores), B (26 cores), and ${\lambda}$ Orionis (15 cores) clouds. We investigate the behavior of the different molecular tracers and look for chemical variations of cores in the three clouds in order to systematically investigate the effects of stellar feedback. The most commonly detected molecular lines (with the detection rates higher than 50%) are $N_2H^+$, $HCO^+$, $H^{13}CO^+$, $C_2H$, HCN, and $H_2CO$. The detection rates of dense gas tracers, $N_2H^+$, $HCO^+$, $H^{13}CO^+$, and $C_2H$ show the lowest values in the ${\lambda}$ Orionis cloud. We find differences in the D/H ratio of $H_2CO$ and the $N_2H^+/HCO^+$ abundance ratios among the three clouds. Eight starless cores in the Orion A and B clouds exhibit high deuterium fractionations, larger than 0.10, while in the ${\lambda}$ Orionis cloud, no cores reveal the high ratio. These chemical properties could support that cores in the ${\lambda}$ Orionis cloud are affected by the photo-dissociation and external heating from the nearby H II region. An unexpected trend was found in the $[N_2H^+]/[HCO^+]$ ratio with a higher median value in the ${\lambda}$ Orionis cloud than in the Orion A/B clouds than; typically, the $[N_2H^+]/[HCO^+]$ ratio is lower in higher temperatures and lower column densities. This could be explained by a longer timescale in the prestellar stage in the ${\lambda}$ Orionis cloud, resulting in more abundant nitrogen-bearing molecules. In addition to these chemical differences, the kinematical difference was also found among the three clouds; the blue excess, which is an infall signature found in optically thick line profiles, is 0 in the ${\lambda}$ Orionis cloud while it is 0.11 and 0.16 in the Orion A and B clouds, respectively. This result could be another evidence of the negative feedback of active current star formation to the next generation of star formation.

• The Journal of the Korea Contents Association
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• v.21 no.12
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• pp.855-869
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• 2021

Since 2009, stars produced through audition programs have appeared through the process of establishing familiar ties with viewers, unlike stars created by entertainment agencies. This study is a case study that examines the characteristics, roles, and identity of internet live broadcasts (Labang) of vocalists Kang Dong-hoon and his fan cafe(fan community) who appeared in JTBC Phantom Singer 3 in 2020. As a result of the study, fans gathered around SNS even before the fan cafe was created, at their request, 'Labang' began. "Labang" is a "freely participating talk show" in which fans actively participate. This brought about the bond of fans, a sense of belonging, and the activation of fandom. Both stars and fans recognized "Live Broadcast" as "a window of communication to get to know each other," and expressed satisfaction that they could see the sincerity of familiar and unpretentious stars, not unrealistic images reproduced on TV through "immediate comment communication." "Labang" consists of a variety of contents, including stars' daily lives, music activities, broadcast appearances, and hobbies, and is showing "aesthetic differentiation" from those who do not watch "Labang" while sharing the daily lives of stars and fans with active participation.

• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.43.1-43.1
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• 2015

We have discovered an unexplored population of galaxies featuring weak broad-line regions (BLRs) at z < 0.2 from detailed analysis of galaxy spectra in the Sloan Digital Sky Survey Data Release 7. These objects predominantly show a stellar continuum but also a broad $H{\alpha}$ emission line, indicating the presence of a low-luminosity active galactic nucleus (AGN) oriented so that we are viewing the central engine directly without significant obscuration. These accreting black holes have previously eluded detection due to their weak nature. The new BLR AGNs we found increased the number of known type 1 AGNs by 49%. Some of these new BLR AGNs were detected at the Chandra X-ray Observatory, and their X-ray properties confirm that they are indeed type 1 AGN. Based on our new and more complete catalogue of type 1 AGNs, we derived the type 1 fraction of AGNs as a function of [OIII] ${\lambda}5007$ emission luminosity and explored the possible dilution effect on the obscured AGN due to star-formation. The new type 1 AGN fraction shows much more complex behavior with respect to black hole mass and bolometric luminosity than suggested by the existing receding torus model. The type 1 AGN fraction is sensitive to both of these factors, and there seems to be a sweet spot (ridge) in the diagram of black hole mass and bolometric luminosity. Furthermore, we present a hint that the Eddington ratio plays a role in determining the opening angles. This work is submitted to ApJS.