• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.3
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• pp.29-58
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• 2022

Recently, Korea has been experiencing a problem of population decline, therefore the transition to a compact spatial structure is being urged. However, what is required is not just physical compression, but a compact city that also considers connectivity, in view of the changes in today's demographic and industrial structure. From this point of view, this study measures the compressibility of domestic cities suffering from extinction risk due to low birth rates, aging population, and population decline, and examined the spatial structure characteristics. In addition to the compressibility evaluation index used in previous studies, the compressibility of six indicators (population, land use, service accessibility, transport accessibility, connectivity, and concentration) was compared and analyzed, and a comprehensive compression index was calculated. The analysis results, based on the comprehensive compression index, classified 2.3% cities in the first grade, 4.6% in the second grade, 16.09% in the third grade, 43.68% in the fourth grade, and 33.33% in the fifth grade areas. Currently, the urban characteristics affecting the compactness index differ from region to region. Therefore, it is necessary to establish measures and policies for extinction risk considering the influence of each region's compactness index. This study is meaningful in that connectivity was considered using spatial syntax, and the compactness of cities at risk of extinction was compared and analyzed quantitatively. It is expected that this study will be used as basic data to establish the direction and action strategy for extinction risk cities.

• Health Policy and Management
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• v.33 no.3
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• pp.253-263
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• 2023

Background: The purpose of this study was to explore the relationship between the local extinction index and total medical service utilization. Methods: A fixed effects model in panel analysis was performed for the 228 administrative districts in Korea. The statistical yearbook on the usage of medical services by region and Korean Statistical Information Service data were used from 2010 to 2019 for analysis. Medical service utilization was represented by the number of visits day, the number of inpatient days, and medical charges. Control variables were selected by using an Anderson model. The local extinction index was calculated using resident registration population data. Results: Descriptive statistics showed that the number of areas at risk of extinction increased from 61 to 95 for the study years. In addition, the number of visits, the number of inpatient days, and medical charges all increased during the study years. After controlling for variables affecting medical service utilization and doing a panel fixed effects model, the result suggested that a one-step increase in the local extinction index was significantly associated with a 12.29% decrease in medical charges of inpatients, a 7.33% decrease in medical charge of outpatient, a 5.21% decrease in the number of inpatient day, and a 5.54% decrease in the number of visits day. Conclusion: This study showed that the higher the region's extinction risks, the higher the region's total medical service utilization. The results of this study suggested that there was a disparity in medical service utilization between areas at risk of extinction and areas not at risk of extinction, so measures should be taken to address this disparity.

• Korean Journal of Environmental Biology
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• v.27 no.1
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• pp.73-81
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• 2009

Population viability analysis of a Gold-spotted pond frog (Rana chosenica) population at Cheongwon-gun, Chungbuk, in South Korea was conducted and we proposed several suggestions for effective conservation and re-introduction of the species. Simulating a developed model over 1,000 times predicted that the population will exist over 30 years with a relatively low growth rate of 0.113, but with a high probability of extinction as 81.1%. Population growth and extinction probability were the most greatly depended on the rate of successful metamorphosis. In the case of outbreak of amphibian diseases such as Chytridiomycosis and Ranavirus, the population will be easily extinct within 4 years with 100% probability. In a habitat of which carrying capacity is 200, to successfully re-introduce an extinct population, it is initially needed to put 100 individuals of which 83% is males and its age structure is normal-distributed. If we additionally conducts artificial supplementation of 10% individuals every 2 years from 4 years to 10 years after initial reintroduction, the population will become a stable with 0.297 growth rate and 0.290 extinction rate. Our results are the first case of amphibian population viability analysis in Korea and could be used to develop effective conservation and re-introduction plans for endangered Gold-spotted pond frog.

• Journal of Korean Society of Rural Planning
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• v.22 no.3
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• pp.119-129
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• 2016

The aim of this study is to suggest the quantitative standard of a marginal village. For the purpose, the study selected 43 villages with the population of 50 or less, the classification of a marginal village in accordance with advanced research and 47 villages with the population over 50 in Buyeo-gun region. The common reason of occurrence of a marginal village suggested by advanced research is a characteristic of a village or decline and extinction of a village rather than a simple index of population or aging rate. Therefore, the study assumed that decline of functions of the village would be caused by decline a function of communities consisting of the villagers. The study then assumed that the relatively low or 0 number or rate of participants would result in community functions. The study conducted t-test on basis of population and aging rate and an analysis to find the range with relatively large differences in the number of communities, participants and the rate of the participants, etc. The result showed that the community function began to decline when the population was less than 60~70 and the aging rate over 75%~85%. As the decline of functions of communities began in population of 70, the critical point was met when the population was 40 or less. With population of 40 or less, the young and the old group communities became extinct or showed rapid decrease in the number of participants. The study assumed that decline of functions of a village, a reason of occurrence of a marginal village would be decline of functions of communities, but there was no further analysis on decline or extinction of a village with population of 40 or less. There shall be further studies about whether a village of population of 40 or less is led to decline of a function or extinction of village communities.

• Korean Journal of Environment and Ecology
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• v.27 no.4
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• pp.417-428
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• 2013

The red fox (Vulpes vulpes), listed as a Class I endangered species by the Ministry of Environment of Korea, has been considered to be extinct in South Korea since the 1980s, and an intensive restoration project has been underway in Sobaeksan national park. This study was carried out to develop a suitable model for the red fox reintroduction program based on Population viability analysis (PVA) by using the VORTEX program. If 10 animals (5 females and 5 males) were continuously released into the initial zero population every year for 10 years, population growth rate and extinction probability over the next 50 years after the introduction of the population were $0.018{\pm}0.204$ and 0.354, respectively; the maximum population size was 116.34 at the 16th year after the first release, and a reduction rate of 1.22 every year from the 17th year was inferred. We found that additional releases would be needed from the 17th year after the initial release to maintain a positive growth rate and to prevent the extinction of the released red foxes, and releasing more than 12 individuals every year would be needed for the long-term, continuous existence of red foxes. By contrast, if fewer than 6 red fox individuals were released the extinction probability over the next 50 years was more than 80%. To maintain the minimum population growth rate, the release of more than 8 individuals were needed for positive population growth. The population growth rate was more stable when 10 animals in the change of their sex rate every year from the set value were released as the female-to- male sex ratio of 6:4 rather than 1:1. However, if the female-biased sex ratio was increased by more than 7:3, a negative population growth was expected. The occurrence rate of roadkill and poaching are important factors in the red fox restoration project. The extinction probability was decreased to 30% if each factor was decreased to 3% based on the standard baseline; however, if each factor was increased to more than 3%, an extinction rate of about 90% was reached over the next 50 years.

• Journal of Astronomy and Space Sciences
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• v.20 no.3
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• pp.175-184
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• 2003

To investigate the SEDs of galaxies considering the dust extinction processes in the galactic disks, we present the population synthesis models for normal galaxies with dusty disks. We use PEGASE (Fioc & Rocca-Volmerange 1997) to model them with standard input parameters for stars and new dust parameters. We find that the model results are strongly dependent on the dust parameters as well as other parameters (e.g. star formation history). We compare the model results with the observations and discuss about the possible explanations. We find that the dust opacity functions derived from studies of asymptotic giant branch stars are useful for modeling a galaxy with a dusty disk.

• Health Policy and Management
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• v.31 no.3
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• pp.301-311
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• 2021

Background: This study purposed to analyze the relationship between the local extinction index and medical service uses of chronic diseases. The local extinction index is an indicator of the demographic structure and population aging of the region. Methods: The 2014-2018 statistics of National Health Insurance Corporation and Korean Statistical Information Service data were used for the analysis. First, descriptive statistics were used to analyze the general status of research variables. Second, a panel analysis was performed to analyze the relationship between the local extinction index and medical service uses of chronic diseases (hypertension, diabetes mellitus, periodontal disease, arthritis, mental health, epidemic disease, liver disease). Medical service uses were measured by the number of visits/inpatient days and medical charges of seven chronic diseases. Results: Panel analysis results showed that higher local extinction risks (meaning lower local extinction index) had a positive relationship with the number of visits/inpatient days and medical charges of chronic diseases. But the relationships were varied when the seven chronic diseases were analyzed separately. Conclusion: This study showed a significant relationship between the local demographic structure and medical service uses of chronic disease. Analyzing the local demographic structure will be an essential prerequisite step for implementing appropriate regional health care policies.

• Journal of Environmental Impact Assessment
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• v.22 no.5
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• pp.525-528
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• 2013

River otter(Lutra lutra) are listed as endangered species and Natural monument in Korea, and this study examined the possibility of extinct of river otter in Hongchon river using with the application of Population Viability Analysis (PVA) technique. In Hongchon river areas population was estimated 9 individuals for the last 1999-2005 years and PVA analysis was done for the next 10 years using the average population of 9. Using the initial population the river otter was estimated 30% of extinct for the next 10 years. This estimation was quite low considering water pollution and construction of highways. Also PVA only used population size lacking in other life history information. Nonetheless river otter population can be in risk of extinction if the current construction of crossovers, cement bank are maintained. Long term information regarding life history needs essential.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.32 no.1
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• pp.79-90
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• 2024

UAM is emerging due to the deepening population concentration in the metropolitan area and the problem of congested ground transportation in urban areas. Accordingly, along with research on eVTOL aircraft for UAM services, interest in vertiport, the interest in vertiports, the infrastructure that allows eVTOLs to take off and land, is also increasing. However, behind the concentration of population in the metropolitan area, aphenomenon of local extinction is occurring in conjunction with the aging population. AAM, which moves quickly through 3D space, can be an effective SOC facility in times of local extinction crisis. In this paper, we introduce a design plan from the perspective of a complex transper center for a regional hub-level vertiport that can connect with local high-speed rail and utilize local airports in compliance with the vertiport design guidelines issued by FAA(Federal Aviation Administration) and EASA(European union Aviation Safety Agency). We would like to present Vertiport's future operation plan.

• Journal of Ecology and Environment
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• v.32 no.2
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• pp.103-107
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• 2009

We investigated colonization and extinction patterns in a meta population of the gold-spotted pond frog (Rana planeyi ehoseniea) near the Korea National University of Education, Chungbuk, Korea, by surveying the frogs in the nine occupied habitat patches in the study area four times per breeding season for three years (2006$\sim$2008) and recording whether the patches were occupied by frogs as well as how many frogs were calling in the patches. We then developed five a priori year-specific models using the Akaike Information Criterion (AIC). The models predicted that: 1) probabilities of colonization and local extinction of the frogs were better explained by year-dependent models than by constant models, 2) there are high local extinction and low colonization probabilities, 3) approximately 31% number of patches will be occupied at equilibrium, and 4) that considerable variation in occupation rate should occur over a 30-year period, due to demographic stochasticity (in our model, the occupation rate ranged from 0.222 to 0.889). Our results suggest that colonization is important in this metapopulation system, which is governed by mainly stochastic components, and that more constructive conservation effects are needed to increase local colonization rates.