• Journal of the Korean Data and Information Science Society
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• v.28 no.2
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• pp.443-449
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• 2017

Estimation of population proportion like the distribution rate of LED TV and the prevalence of a disease are often estimated based on survey sample data. Population proportion is generally considered as a special form of population mean. In complex sampling like stratified multistage sampling with unequal probability sampling, the denominator of mean may be random variable and it is estimated like ratio estimator. In this research, we examined the estimation of distribution rate based on stratified multistage sampling, and determined some numerical outcomes using stratified random sample data with about 25% of missing observations. In the data used for this research, the survey weight was determined by deterministic way. So, the weights are not random variable, and the population distribution rate and its variance estimator can be estimated like population mean estimation. When the weights are not random variable, if one estimates the variance of proportion estimator using ratio method, then the variances may be inflated. Therefore, in estimating variance for population proportion, we need to examine the structure of data and survey design before making any decision for estimation methods.

• Animal Systematics, Evolution and Diversity
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• v.28 no.4
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• pp.279-290
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• 2012

Plecoglossus altivelis (ayu) is an amphidromous fish widely distributed in Northeastern Asia from the East China Sea to the northern Japanese coastal waters, encompassing the Korean Peninsula within its range. The shore lines of northeastern region in Asia have severely fluctuated following glaciations in the Quaternary. In the present study, we investigate the population genetic structure and historical demographic change of P. altivelis at a population level in East Asia. Analysis of molecular variance (AMOVA) based on 244 mitochondrial control region DNA sequences clearly showed that as the sampling scope extended to a larger geographic area, genetic differentiation began to become significant, particularly among Northeastern populations. A series of hierarchical AMOVA could detect the genetic relationship of three closely located islands between Korea and Japan that might have been tightly connected by the regional Tsushima current. Neutrality and mismatch distribution analyses revealed a strong signature of a recent population expansion of P. altivelis in East Asia, estimated at 126 to 391 thousand years ago during the late Pleistocene. Therefore it suggests that the present population of P. altivelis traces back to its approximate demographic change long before the last glacial maximum. This contrasts our a priori expectation that the most recent glacial event might have the most crucial effect on the present day demography of marine organisms through bottleneck and subsequent increase of effective population size in this region.

• Korea journal of population studies
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• v.3 no.1
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• pp.62-77
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• 1979

The purpose of this study is to explain the increasing trend of the aged population and its demographic characteristics. This study is based on the data for the aged population above 65 years old published by the Bureau of Statistics, Economic Planning Board. The increasing trend of the aged population has been analyzed and projected from 1955 to the year 2000. Some demographic charicteristics of the aged population including marital status, educational status and status of economic activities have also been analyzed in order to identify the problems associated with aging of population in Korea. The study offers the following conclusion. 1. The aged population index, the proportion of aged population to total population was 3.6 in 1975 and projected to be 6.6 in 2000. There has been steady increase of the aged population is reflected in changes of population structure. The proportional change of the aged population index was 100.0 in 1955, 109.0 in 1975 and 200.0 in 2000 respectively. 2. As for marital status of the aged population 77.6 per cent of male were married while 24.3 per cent of female were married in 1975. 22 per cent of male were widowed while it spouses died declined remarkable the mortality rate declined. 3. As the educational status of the aged, 77 per cent never attended school and 18 per cent attended from a primary school. This is very low and the number of educated men is higher than that of educated women. The rank ordering of schooling is city, Eub and Myeon in that aged. 4. The dependency ratio of the aged population was 5.9 in 1955, 6.1 in 1975 and will be 9.8 in 2000. It is gradually increasing as indicated above 20 per cent of aged population was economically active of these, they are employed in the following occupations as listed in order of the magnitude of the aged population employed. The employment status of the aged workers shows that a greater number of persons are self-employed than workers for another employer. In particular, temporary employees comprise 56.0 per cent of those employed.

• Communications for Statistical Applications and Methods
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• v.4 no.1
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• pp.207-218
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• 1997

We consider two models for the growth of population with overlaping generations. First, the model we will describe is basically the model given by Leslie(1945). This is only a one-sex model of population age structure and growth. Next, we introduce a model in which couples must be formed before reproduction occurs. If the maximum number of couples is formed, and if the couples are only formed from fermales of age x-a and males of age x at time t, $\alpha$ > 0. Then, we will solve the renewal equations for the reproductive value.

• Asian Journal of Business Environment
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• v.9 no.4
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• pp.23-28
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• 2019

Purpose - With rapid population aging in Korea, changes in the population structure will result in a rise in the fiscal burden. This paper investigates the effects of population aging on fiscal spending based on Korea's province data and country panel data from the OECD. Research design, data, and methodology - We use province-level fiscal data from Local Finance Integrated Open System and the Korean Statistical Information Service and also collect country panel data from the OECD. To investigate the relationship between population aging and fiscal expenditures, our analysis uses the fixed effects model. Results - The empirical analysis based on Korean local finance and country panel data show that population aging has a positive impact on social welfare expenditures and it also has a positive impact on spending related to children and the elderly, implying that population aging may lead to an increase in fiscal spending via an increase in social welfare expenditures and spending related to children and the elderly. Conclusion - These empirical results suggest that countries like Korea that expect to experience rapid population aging need to pay more attention to prepare for the expected increase in age-related spending in the near future.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.65 no.4
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• pp.447-456
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• 2020

Peanut is an allotetraploid derived from a single recent polyploidization. Polyploidization has been reported to have caused significant loss in genetic diversity during the domestication of cultivated peanuts. Single nucleotide polymorphism (SNP)-based markers such as cleaved amplified polymorphic sequences (CAPS) derived from next-generation sequencing (NGS) have been developed and widely applied for breeding and genetic research in peanuts. This study aimed to identify the genetic diversity and population structure using 30 CAPS markers and 96 peanut accessions from five different origins. High genetic dissimilarities were detected between the accessions from Korea and those from the other three South American origins generally regarded as the origin of peanuts, while the accessions from Brazil and Argentina presented the lowest genetic dissimilarity. Based on the results of the present study, accessions from Korea have unique genetic variation compared to those from other countries, while accessions from the other four origins are closely related. Our study identified the genetic differentiation in 96 peanut accessions from five different origins, and this study also showed the successful application of SNP information derived from re-sequencing based on NGS technology.

• ALGAE
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• v.23 no.2
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• pp.141-150
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• 2008

Populations of Codium amplivesiculatum were found in association with rhodolith beds. We present population trends of C. amplivesiculatum from surveys conducted in the southwestern Gulf of California based on monthly sampling from June 1999 to August 2000. Surveys were conducted at 2 sites in the San Lorenzo Channel at depths of 8 - 12 m. The parameters measured were percent cover, biomass and structure in relation to size of the thalli. From each thallus the following measurements were taken: length and diameter, proportion of each thallus with reproductive structures and the degree of fragmentation (measured as number of small thalli). Mean biomass and cover varied seasonally with the maximum (1036.6 gm$^{-2}$ and 100% cover) present in June 2000 and the minimum in winter (0 gm$^{-2}$ and 0% cover). The longest fronds (3 m) occurred during July 1999 and August 2000, while the maximum diameters of 1.0 cm were present during October and November 1999. There were no significant linear relationships between length and diameter of the fronds, suggesting independent growth. Reproductive structures were common in June and July 1999 with monoic and dioic thalli present. Most fronds were monoic, and this is the first record of this feature for this species. Fragmentation occurred in September, and may be associated with stress from early gametangial reproduction and the combination of high temperatures and low nutrients. A hypothetical life cycle for the species is presented.

• Animal cells and systems
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• v.16 no.6
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• pp.498-505
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• 2012

This study uses the mitochondrial DNA control region to identify the genetic diversity and population structure of the marbled soles (Pleuronectes yokohamae) that inhabit Jinhae Bay and Yokji Island in the nearby sea and the adjacent waters of Namhae, Hansan Island, and Jaran Bay. Direct sequencing of the PCR products revealed 379 bp sequences with 83 variable nucleotide sites, defining a total of 91 haplotypes. The haplotype diversity was high, ranging from $0.917{\pm}0.031$ to $0.983{\pm}0.008$, and nucleotide diversity ranged from $0.015{\pm}0.008$ to $0.024{\pm}0.012$. In addition, 48 haplotypes (52.7%) were unique. Pairwise $F_{ST}$ values were very low, with the maximum value occurring between PYH (Hansan Island) and PJI (Jinhae Bay) ($F_{ST}$ = 0.011). Therefore, no significant genetic differentiation was evident between any pair of sampling localities.

• Journal of Forest and Environmental Science
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• v.25 no.3
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• pp.187-194
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• 2009

This study was carried out to investigate vegetation structure and soil property of natural habitat of Polygonatum stenophyllum to provide basic information for propagation, conservation and restoration. Habitats of Polygonatum stenophyllum were classified into Hemiptelea davidii-Robinia pseudo-acacia dominant population (Yeongwol-eup), Pinus densiflora-Hemiptelea davidii-Callicarpa japonica dominant population (Nam-myeon), and Hemiptelea davidii-Rubus crataegifolius dominant population (Gangchon-ri). The soil pH 6.49~7.28; and electron conductivity 0.10~0.19 ds/m. The average content of organic matter, total nitrogen, available $P_2O_5$, $Ca^{2+}$, $Mg^{2+}$, $K^+$, and $Na^+$ were 8.24~16.45 g/kg, 0.02~0.13%, 45.67~123.67 mg/kg, 4.61~6.71 cmol(+)/kg, 0.17~0.63 cmol(+)/kg, 0.06~0.27 cmol(+)/kg and 0.03~0.30 cmol(+)/kg, respectively. Species diversity index (H'), maximum species diversity index (H' max), evenness (J') and dominance (1-J') of investigated sites ranged 1.0323 (Nam-myeon)~1.1134 (Yeongwol -eup), 1.4914 (Gangchon-ri)~1.6128 (Nam-myeon), 0.6401 (Nam-myeon)~0.7270 (Yeongwol-eup) and 0.2730 (Yeongwol-eup)~0.3599 (Nam-myeon) respectively.

• Mycobiology
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• v.48 no.2
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• pp.115-121
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• 2020

In this study, the genetic diversity and the population structure of 77 wild strains and 23 cultivars of Lentinula edodes from Korea were analyzed using 20 genomic SSRs, and their genetic relationship was investigated. The tested strains of L. edodes were divided into three sub-groups consisting of only wild strains, mainly wild strains and several cultivars, and mainly cultivars and several wild strains by distance-based analysis. Using model-based analysis, L. edodes strains were divided into two subpopulations; the first one consisting of only wild strains and the second one with mainly cultivars and several wild strains. Moreover, AMOVA analysis revealed that the genetic variation in the cultivars was higher than that in the wild strains. The expected and observed heterozygosity and values indicating the polymorphic information content of L. edodes cultivars from Korea were also higher than that of the wild strains. Based on these results, we presume that the cultivars in Korea have developed by using numerous strains from other countries. In conclusion, the usage of wild strains for the development of new cultivars could improve the adaptability of L. edodes to biotic and abiotic stress.