• Journal of the Korean Geographical Society
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• v.37 no.5
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• pp.498-510
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• 2002

This study has the following two focuses to analyze the changes in national-level locational pattern of the U.S. professional sports franchises during 1950-2001. The first is to empirically clarify spatial orientation in the changing locational pattern of sports franchises. The second is to identify compared characteristics of the relocation cases reflecting the orientation to other cases, for the variables indicative of franchises' and leagues' pursuits of their relocation-related interests ultimately affecting franchises' relocations, by employing a legit model. As a result of the analyses, sports franchises and leagues, respectively have shown spatial orientation toward relocating to and toward locating new franchises in southern and western areas, responding to the changes in U.S. urbanization pattern. And, relocation cases reflecting the orientation have displayed a feature of the higher annual population growth rate in destination urban area than in origin area, in comparison to other cases.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.38.2-38.2
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• 2013

Several studies have reported the presence of sodium excess objects having neutral atomic absorption lines at $5895{\AA}$ (NaD) and $8190{\AA}$ that are deeper than expected based on stellar population models that match the stellar continuum. The origin of these lines is therefore hotly debated. van Dokkum & Conroy proposed that low-mass stars (0.3M) are more prevalent in massive early-type galaxies, which may lead to a strong NaI 8190 line strength. It is necessary to test this prediction, however, against other prominent optical line indices such as NaD, Mgb, and Fe5270, which can be measured with a significantly higher signal-to-noise ratio than NaI 8190. We identified a new sample of roughly one thousand NaD excess objects (NEOs; ~8% of galaxies in the sample) based on NaD line strength in the redshift range 0.00${\alpha}$-enhanced" ([${\alpha}/Fe$] ~ 0.3), "metal-rich" ([Z/H] ~ 0.3), and, especially, "Na-enhanced" ([Na/Fe] ~ 0.3).

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.36-36
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• 2013

Globular clusters (GCs) are among the oldest stellar objects in the universe and provide valuable constraints on many aspects of galaxy evolution. GC systems typically exhibit bimodal color distributions the phenomenon of which has been a major topic in the area of GC research. GC color bimodality established a paradigm where scenarios to explain its origin require two GC groups with different formation origins. The GC division, asserted mainly by photometric color bimodality so far, has been viewed as the presence of two distinct metallicity subgroups within individual galaxies. In this study, we make use of spectroscopy of GC systems associated with two giant galaxies, M31 (the Andromeda) and M87 (NGC 4486), to investigate the GC bimodality and the underlying metallicity distributions. Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Given that spectroscopy is a more detailed probe into stellar population than photometry; the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We present spectra of 130 old globular clusters (GCs) associated with the Virgo giant elliptical galaxy M87, obtained using the Multi-Object Spectrography (MOS) mode of Faint Object Camera and Spectrograph (FOCAS) on the Subaru telescope. M87 GCs with reliable metallicity measurements exhibit significant inflection along the color-metallicity relations, through which observed color bimodality is reproduced from a broad, unimodal metallicity distribution. Our findings lend further support to this new interpretation of the GC color bimodality, which could change much of the current thought on the formation of GC systems and their host galaxies.

• The Bulletin of The Korean Astronomical Society
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• v.38 no.2
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• pp.47.2-47.2
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• 2013

We present ultraviolet (UV) color-magnitude relations (CMRs) of early-type dwarf galaxies in the Viro cluster, combining Galaxy Evolution Explorer (GALEX) UV data with SDSS optical data, based on the Extended Virgo Cluster catalog (EVCC). We find that dwarf lenticular galaxies (dS0s) show a surprisingly distinct and tight locus separated from that of ordinary dEs, which is not clearly seen in previous CMRs. The dS0s in UV CMRs follow a steeper sequence than dEs and show bluer UV-optical color at a given magnitude. We explore the observed CMRs with population models of a luminosity-dependent delayed exponential star formation history. The observed CMR of dS0s is well matched by models with relatively long delayed star formation. The dS0s are most likely transitional objects at the stage of subsequent transformation of late-type progenitors to ordinary red dEs in the cluster environment. Most early type dwarf galaxies with blue UV colors (FUV-r < 6 and NUV-r < 4) are identified as those showing spectroscopic hints of recent or ongoing star formation activities. In any case UV photometry provides a powerful teel to disentangle the diverse subpopulations of early-type dwarf galaxies and uncover their evolutionary histories. lenticular galaxies, and irregular high surface brightness (HSB) galaxies, respectively. Dwarf elliptical galaxies and dwarf irregular LSB galaxies occupy the similar structural parameter spaces. We suggest that giant elliptical galaxies and dwarf elliptical galaxies may have different origin.

• Publications of The Korean Astronomical Society
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• v.32 no.1
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• pp.135-139
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• 2017

We have performed systematic studies of the properties of dust in various environments of nearby galaxies with AKARI. The unique capabilities of AKARI, such as near-infrared (near-IR) spectroscopy combined with all-sky coverage in the mid- and far-IR, enable us to study processing of dust, particularly carbonaceous grains includings polycyclic aromatic hydrocarbons (PAHs), for unbiased samples of nearby galaxies. In this paper, we first review our recent results on individual galaxies, highlighting the uniqueness of AKARI data for studies of nearby galaxies. Then we present results of our systematic studies on nearby starburst and early-type galaxies. From the former study based on the near-IR spectroscopy and mid-IR all-sky survey data, we find that the properties of PAHs change systematically from IR galaxies to ultraluminous IR galaxies, depending on the IR luminosity of a galaxy or galaxy population. From the latter study based on the mid- and far-IR all-sky survey data, we find that there is a global correlation between the amounts of dust and old stars in early-type galaxies, giving an observational constraint on the origin of the dust.

• Journal of Korean Society of Transportation
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• v.24 no.3 s.89
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• pp.7-15
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• 2006

A large sample can Provide more information about the Population. As the sample size Increases, analysts will be more confident about the survey results. On the other hand, the costs for survey will increase in time and manpower. Therefore, determination of the sample size is a trade-off between the required accuracy and the cost. In addition, permitted error and significance level should be considered. Sample size determination in surveys for O/D estimation is also connected with confidence of survey result. However, the past methods were usually too simple to consider confidence. Therefore, a new method for O/D surveys was Proposed and it was accurate enough, but it has too large sample size when we have current budget constraint. In this research, several minimum sample size determination methods for origin-destination survey under budget constraint were proposed. Each method decreased sample size, but has its own advantages. Selection of the sample size will depend on the study Purpose and budget constraint.

• Journal of the Korea Furniture Society
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• v.18 no.4
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• pp.317-323
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• 2007

Almost all the people, particularly the rural people are directly dependent on the continued productivity of natural resources, like water, soils, forests and fisheries. But the overuse by the extremely high population pressures has degraded the natural resources into severe widespread deforestation. The degradation of natural resources, particularly the plant resources has been a great concern for socio-economic and sustainable development of the country. The Forests in Bangladesh have been depleted and degraded in volume, area, and quantity, thus requiring urgent forest protection by identifying the causes of forest loss. There are so many causes of deforestation and loss of genetic resources such as; the timber industry, which, legal or not, are cutting too many trees; indigenous forest dwellers, having their own types of problems; migrants, who, because of problems in their places of origin, have decided to move to the forests and the government through its Forest Department which is not able or willing to implement suitable policies to regulate the cutting trees and to prevent illegal cutting. Because it is a time consuming task to mitigate the first and second sets of factors, we recommend involving forest dwellers in forestry practices as much as possible and taking necessary steps to alleviate the third and fourth sets and thereby reduce the rate of forest depletion. Accordingly, a number of strategies that should be adopted to halt the loss of remaining forest cover are discussed.

• Journal of Ecology and Environment
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• v.44 no.3
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• pp.155-161
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• 2020

Glossy Ibis (Plegadis falcinellus), which has never been recorded in South Korea, appeared on Jeju Island in 2018 and re-emerged in the inland area of Seocheon-gun (South Chungcheong Province) and in Goyang-si (Gyeonggi Province) in the following year. This study aims to report the progress in observing P. falcinellus in the inland areas of South Korea in 2019 and to predict its origin region and future propensity for habitats in the country through literature review. On 5 May 2019, an individual of P. falcinellus with breeding feathers was observed in a farmland in Wolsan-ri, Seocheon-gun. Twelve days later, another one was identified in a farmland in Janghang-dong, Goyang-si, about 173 km north of Wolsan-ri. The observed birds fed and rested in the area and stayed for only a day. The individual birds spotted in South Korea in 2019 are conjectured to have come from either Southeast Asia or Australia, among areas located in East Asian-Australasian Flyway (EAAF). This is because P. falcinellus, a species with excellent dispersal capacity, forms a population in new areas during extreme environmental changes in their current habitats, especially droughts. For 2 years, P. falcinellus was observed to be migrating in spring; however, in the future, they may exhibit the same propensity for breeding and habitats as that of birds migrating in autumn. As it is a conspicuous species, effective detection of their arrival requires a survey system that classifies the country by habitat type and involves periodic and multiple observations by experts and citizens.

• Clinical and Experimental Pediatrics
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• v.59 no.3
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• pp.132-138
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• 2016

Purpose: Acute respiratory infection, particularly pneumonia, is the most common cause of hospitalization and death among children in developing nations. This study aimed to investigate the characteristics of children and adolescents with pneumonia who visited Emergency Department (ED) in South Korea in 2012. Methods: We analyzed National Emergency Department Information System (NEDIS) records from 146 EDs in South Korea for all pediatric patients aged ${\leq}18years$ who were diagnosed with pneumonia between January and December 2012. Results: Among 38,415 subjects, the male-to-female ratio was 1:0.8. Patients aged <12 months comprised 18.0% of the study population; those aged 1 to 3 years, 54.4%; those aged 4 to 6 years, 16.8%; those aged 7 to 12 years, 7.4%; and those aged 13 to 18 years, 3.4%. Presentation rates were highest in April, followed by January, March, and May. The hospital admission rate was 43.5%, of which 2.6% were in intensive care units. The mortality rate was 0.02%. Based on the International Classification of Diseases, 10th Revision, diagnostic codes, the types of pneumonia according to cause were viral pneumonia (29.0%), bacterial pneumonia (5.3%), Mycoplasmal pneumonia (4.5%), aspiration pneumonia (1.3%), and pneumonia of unknown origin (59.3%). Conclusion: Despite the limited data due to the ED data from the NEDIS lacking laboratory results and treatment information, this study reflects well the outbreak patterns among children and adolescents with pneumonia. Our results provide a basis for future studies regarding ED treatment for children and adolescents with pneumonia.

• Journal of Preventive Medicine and Public Health
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• v.29 no.3 s.54
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• pp.555-563
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• 1996

Nationwide incidence survey was conducted to estimate the annual incidence rates of colorectal cancer among Koreans between Jan 1, 1988 and Dec 31, 1989. The population of the incidence survey was the beneficiaries of Korea Medical Insurance Corporation (KMIC), which were about 4,500,000 persons. The medical records of patients with diagnosis of either ICD-9 153(colon cancer), 154(rectal caner), 197(secondary malignant neoplasm of digestive and respiratory system), or 211(benign neoplasm of digestive system) were abstracted for the period with the standard format. The diagnosis was confirmed by one oncologist through the review of these abstracts. The numerator of the rate was finally defined as the incident colorectal cancer cases diagnosed between July 1, 1988 and June 30, 1989. The crude annual incidence of colorectal cancer for men was 13.1 per 100,000 and 10.6 for women, which was still low when compared with those of Japan and China during the same period. Age-adjusted sex ratio was 1.2 for right-sided colon cancer and 1.9 for left-sided colon cancer. The excess of right colon cancer among postmenopausal women was remarkable, so further analytical approach would be needed to investigate which factors are related with this phenomenon.