• Korean System Dynamics Review
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• v.17 no.1
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• pp.107-134
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• 2016

Accelerated ageing with low fertility is one of the most critical problems in Korea. Because of ageing via low fertility, Korea will face a serious demographic cliff. This research primarily focus on the analyzing the dynamics of the marginal ageing state and decreasing population especially in Eup and Myeon region. This study based on the system dynamics approaches for finding causal loop structure of marginal ageing and critical mass of population disappearing. The results of this study are summarized as follows. First, demographic marginalization trends have already begun in the Eups and Myons of Gun. Second, marginal aging speed in Eup/Myeon areas is causing an population disappearing in the near future. Third, critical mass of population disappearing will begin when the rate of marginal aging is exceed 82% after 2023.

• 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.

• Communications for Statistical Applications and Methods
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• v.11 no.2
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• pp.419-433
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• 2004

We suggest the modified computing algorithm for raking ratio estimation under the assumption that the population total is partially known, and the sample total is completely known about survey variable in contingency table. We show that the proposed estimation procedure is useful to estimate the population cell count in this situation through an empirical study.

• Journal of the Korean housing association
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• v.25 no.3
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• pp.35-43
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• 2014

Korea is the most rapidly aging country in the OECD countries, becoming 'an aging society' in 2010, when over 12% of the population had reached the age 65 and beyond. Along with the population aging, problems of the elderly have become a social issue. Also, the elderly population in most farming villages is increasing due to the cityward concentration of younger generation and the rapid urbanization centered around the capital area. Yet no definite success in revitalization of these villages has been reported despite the acknowledgement of the problems arising from such phenomena. Therefore, by examining "marginal villages" (communities whose joint social activities are difficult to maintain as over 50% of the population is 65 years or older) in Japan, which at this point has entered "the ultra-aged society" before Korea, this study intends to compare and analyze the countermeasure plans for the population decrease in these villages. The case study has been done with the focus on the literary references published in Japan such as papers, various reports, statistics, newspapers, and journals.

• Journal of the Korean association of regional geographers
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• v.22 no.3
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• pp.515-528
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• 2016

Since 1960s the rural population of Korea has continually decreased as a result of the rapid rural-to-urban migration and this caused an economic recession as well as the accelerated aging phenomenon in the rural communities. Such problems got worse in smaller rural villages and marginal villages began to appear among the rural communities. This study aims to analyze the structures and characteristics of rural marginal villages. A case study on the county of Goheung, Jeollanamdo, is carried out using survey and stakeholder interviews. With the survey results a series of comparative analysis are done revealing the commonalities and peculiarities between two different types of marginal villages. This study also tries to reveal the residents's perceptions on the marginal villages and the potential determinants of rural rehabilitation.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.649-663
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• 1998

The clarify the ecological properties, and to predict change of understory vegetation of mt. Nam Park, population dynamics and interspecific competition of D. smilacinum and D. viridescens, which grow in understory of deciduous broad-leaved forest and pseudo-annuals, were studied from May 20 to May 30 1998. The depth of litter layer, soil moisture content, soil organic matter and soil texture were surveyed in 18 populations (15 D. smilacinum populations and 3 D. viridescens populations). Mean litter layer of d. smilacimum population was thinner than that of D. viridescens populations). Mean litter layer of D. smilacnum population was thinner than that of D. viridescens population. The contents of soil moisture and organic matter of D. smilacinum population were lower than that of D. viridescens population. The D. smilacinum growed in broad range of soil texture but D. viridescens in loamy soil. Because D. smilacinum could tolerate more broad range of soil moisture and soil texture than D. viridescens, the former covered the herb layer in earlier stage and the latter introduced in later stage when rhizome could grow easily. The numbers of individual in two marginal parts were smaller than that in center in same D. smilacinum patch. And the total numbers of individuals grown in (10 ${\times}$ 10)cm were from 0 to 12. The rhizome (subterranean runner) weight, rhizome length, root weight, shoot weight, lea weight and leaf number per subquadrat (cell) increased along the number of individual, that is, increased from marginal part to center. But rhizome weight and rhizome length per individual were vice versa. Therefore, the individuals in marginal part reproduced longer and stronger asexual propagules than that in center. The distribution pattern of D. smilacinum was contageous and that of D. viridescens was random or regular. Therefore, population growth of former was independent on density and that of latter was dependent on density. The distributions of size-class showed normal curves in two population, but the curves based on data of total dry weight showed positive skewness and those of leaf number showed negative skewness The correlation coefficient (CC) values between the properties of each organ were high in two population and significant at 0.1% level. The CC values of D. viridescens were higher of the two. Therefore, the former allocated the energy to each organ stable. The rhizome depth of d. viridescens was 2 times deeper than that of D. smilacinum. And rhizome length and weight of D. viridescens were longer (2 times) or heavier (4 times) than those of D. smilacinum. The patch size of D. viridescens increased 60 cm per year and that of D. smilacinum 30 cm. On this results, the intrinsic increase velocity of d. viridescens patch was 2 times faster than that of d. smilacinum, therefore, on the competition, the former had an advantage over D. smilacinum. The reason why d. viridescens defeated D. smilacinum resulted from that the leaf area of former was 4 times broader than that of latter. in Mt. Nam Park, it was thought that two disporum Population would change with the 3 thpes of environmental change as followings. First, no human impact and increase of soil moisture content resulted in increase of D. viridescens population. Second, mild human impact and similar condition of soil moisture content resulted in slow increase or no changes of D. smilacinum and d. viridescens population. Third, severe human impact and dry condition resulted in decrease or vanishment of two disporum populations.

• Journal of Korean Society of Rural Planning
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• v.24 no.1
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• pp.21-31
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• 2018

This study is a basic research for the development of 'Marginal Village Policy' in response to the hollowing-out of rural areas. For this purpose, the viewpoint of "Regeneration" & "Reconstruction" of the "Marginal Village Theory" and the recent "Rural Planning Theory of Evacuation" in Japan were reviewed. The background and trends of Marginal Village policy in Japan were also investigated. And based on this, the implications and future tasks for Korea were summarized as follows; (1)It is necessary to be interested in the disappearance of villages and marginal villages and to form positive discussions and social consensus. (2)Continuous field investigation and management of changes in population and village functions at regional and village level are required. (3)In addition to increasing the importance of depopulation problems, it is necessary to establish 'marginal villages' as a public policy target. (4)It is necessary to review and consider the viewpoint of reconstruction along with regeneration. (5)It is necessary to pay attention that the software project is expanded, and the regeneration & reconstruction policies of the rural villages are aimed at revitalizing the rural community. (6)It is necessary to consider the possibility of applying 'spacial construction' along with the expansion of the academic debate on the 'rural planning theory of evacuation'. On the basis of this, in this study, rural villages were classified into 'continuous villages', 'semi-marginal villages' and 'marginal villages' according to the degree of marginalization, and the basic framework of 'Marginal Village Policy' was proposed, which is to encourage the differentiated policies of 'continuous villages' by 'rural village policy', 'semi-marginal villages' and 'marginal villages' by 'marginal village policy'.

• Journal of Wetlands Research
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• v.22 no.2
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• pp.100-105
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• 2020

Northern pipevine (Aristolochia contorta) commonly inhabits marginal areas between waterside and terrestrial vegetation. In particular, A. contorta is ecologically important in the marginal areas as a food plant of dragon swallowtail butterfly (Sericinus montela), which is designated as vulnerable species in the Republic of Korea. For long-term sustainability of the plant population, assessment of the genetic diversity of exist populations should be conducted. Genomic DNA of A. contorta leaf samples were extracted from four populations where the vigorous growth were observed in the South Korea. Intra-population genetic diversity and inter-population genetic distance were assessed using randomly amplified polymorphic DNA (RAPD) with five polymorphic random primers. Overall genetic diversity was lower, compared to other wetland species (h: 0.0607 ~ 0.1401; I: 0.0819 ~ 0.1759), while GP showed the highest intra-population genetic diversity. Despite of the geographical distance, GP showed the larger genetic distance from other populations. This result seemed to be caused by the fragmented habitat and lower sexual reproduction of A. controta. Mixture of the different source populations and construction of the proper environmental condition such as shade and physical support for sexual reproduction should be considered for conservation of A. contorta population.

• Journal of Korean Society of Rural Planning
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• v.21 no.4
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• pp.85-94
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• 2015

The purpose of this study is to investigate how the hollowization in rural villages which causes marginal villages appears in Korean rural villages and whether the hollowization has relation with decrease and aging of population or not. For achieving the research objective, survey was carried out focused on Geumsan-gun. As a result, it confirmed that rural out-migration and rural decline especially in 'people', 'land(economic situation)' and 'community' have being progressed. Also variance analysis and regression analysis were executed with using the number of population and the ratio of people over 65 as dependent variables and using each survey contents(variables) as independent variables. The results of analysis showed that the ratio of people over 65(+), the income level per household(-), the rate of fallow lands(+), the number of empty houses(+), programs for urban-rural interchange(+), and the implementing public projects(+), etc. have a relation with the number of population(-) and the number of population(-), the income level per household(-), the rate of fallow lands(+), the number of empty houses(+), activities of communities(+), and the implementing public projects(+), etc. have a relation with the ratio of people over 65(+) (+: increase, -: decrease). So the hollowization in people', 'land(economic situation)' and 'community' has direct relation with decrease and aging of population in rural areas.

• The Journal of the Korean dental association
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• v.56 no.7
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• pp.366-374
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• 2018

Purpose : The purpose of this study was to compare the marginal fit of monolithic zirconia restorations fabricated form the conventional and the digital impression technique. Materials and methods : Ten patients were restored with monolithic zirconia restorations fabricated from the digital and the conventional impression technique. Before definitive insertion, silicone replicas were produced from all twenty crowns. The silicone replicas were cut in three sections; each section was evaluated at two points. The measurement was carried out by using a measuring microscope (Olympus BX 51) and I-Solution. Data from the silicone replica scores were analyzed by Shapiro-Wilk test for normal distribution and the t-test for equality of two population's mean. All tests were performed with ${\alpha}-level$ of 0.05. Results : The average marginal gaps of monolithic zirconia restorations were $133.81{\pm}36.46{\mu}m$ for the conventional impression technique, $90.07{\pm}9.47{\mu}m$ for the digital impression technique. No statistical differences were found between the two impression techniques Conclusion : Both prostheses presented clinically acceptable results with comparing the marginal fit.