• The Plant Pathology Journal
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• v.37 no.3
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• pp.280-290
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• 2021

Population genetic studies of Hemileia vastatrix have been conducted in order to describe the evolutionary dynamics of the pathogen and the disease epidemiology as consequence of changes in disease management and host distribution occurred in Peru after the 2013 epidemic. These analyses were performed by sequencing the internal transcribed spacers of the nuclear ribosomal DNA (rDNA-ITS) of H. vastatrix collected from two coffee growing areas in 2014 and 2018. H. vastatrix population showed high haplotype diversity (Hd = 0.9373 ± 0.0115) with a low nucleotide diversity (π = 0.00322 ± 0.00018). Likewise, AMOVA indicated that fungus population has behaved as a large population without structuring by geographical origin and sampling years (F_ST = 0.00180, P = 0.20053 and F_ST = 0.00241, P = 0.19693, respectively). Additionally, the haplotype network based on intraspecific phylogenetic analysis of H. vastatrix using Peruvian and NCBI sequences revealed that Peruvian ancestral haplotypes, which were maintained in time and space, would correspond to the reported sequences of the races II and XXII. This result suggests that no substantial changes have occurred through time in Peruvian Hemileia vastatrix population.

• The Korean Journal of Applied Statistics
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• v.33 no.6
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• pp.697-712
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• 2020

New infectious diseases have broken out repeatedly across the world over the last 20 years; COVID-19 is causing drastic changes and damage to daily lives. Furthermore, as there is no denying that new epidemics will appear in the future, there is a continuous need to develop measures aimed towards responding to economic damage. Against this backdrop, the living population is an important indicator that shows changes in citizens' life patterns. This study analyzes time-based and socio-environmental characteristics by detecting and classifying changes in everyday life caused by COVID-19 from the perspective of the floating population. k-shape Clustering is used to classify living population data of each of the 424 dong's in Seoul measured by the hour; then by applying intervention analysis and One-way ANOVA, each cluster's characteristics and aspects of change in the living population occurring in the aftermath of COVID-19 are scrutinized. In conclusion, this study confirms each cluster's obvious characteristics in changes of population flows before and after the confirmation of coronavirus patients and distinguishes groups that reacted sensitively to the intervention times on the basis of COVID-related incidents from those that did not.

• Journal of Environmental Science International
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• v.1 no.1
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• pp.23-27
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• 1992

The changes of pectoral muscle size (as an index of protein reserves) and fat reserves (as an index of lipid) were measured in wintering Dunlin during 1988 -1989 on two estuaries located in the south coast of Korea. The mean of lean mass of February population was greater(11.8%) than that of October population. SMI of October population was greater(4.5%) than that of February population and lipid index of October population also greater(1.6%) than that of February population. This show that the body condition of October population is better than February population. The mean of fat and protein reserves of 22 % of Dunlin arriving on October for their wintering were higher than that of others, this group seems to continue their migration to south further and 11% of the wintering population seems to starve during winter.

• Journal of Wetlands Research
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• v.19 no.2
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• pp.223-229
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• 2017

This study analyzed the relationship between environmental factors and the temporal changes of the bird populations during the every January from 1999 to 2016 (18 years) in Donglim reservoir. 'Winter Waterbird Census of Korea' data by National Institute of Biological Resources were used for the bird population data, and principal component analysis and cluster analysis were used to analyze the changes of annual population. The average temperature of January and the average storage rate of the reservoir were used as environmental factors. According to the results of the study, the population changes in the study area can be explained by the increase and decrease of two water bird groups and a mountain bird group. The average temperature of the years when the population of water bird groups increased was more than $1.4^{\circ}C$ in comparison with the year when mountain birds increased. On the other hand, the influence of the water content was not clear. The visiting of Baikal Teal affected by temperature was a factor affecting the other group of water bird and a mountain bird group. The results of this study suggest that the temperature change affects the global spatial distribution of birds and the migration of large population species such as Baikal Teal affects species composition and populations of birds at local scale. Therefore, understanding of environmental changes at large scale and spatial distribution of species and flock contributes to understand the temporal variation of the bird population at regional or local scales.

• Journal of Environmental Health Sciences
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• v.47 no.6
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• pp.521-529
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• 2021

Background: The coronavirus disease (COVID-19) has caused changes in human activity, and these changes may possibly increase or decrease exposure to fine dust (PM_2.5). Therefore, it is necessary to evaluate the exposure to PM_2.5 in relation to the outbreak of COVID-19. Objectives: The purpose of this study was to compare and evaluate the exposure to PM_2.5 concentrations by the variation of dynamic populations before and after the outbreak of COVID-19. Methods: This study evaluated exposure to PM_2.5 concentrations by changes in the dynamic population distribution in Guro-gu, Seoul, before and after the outbreak of COVID-19 between Jan and Feb, 2020. Gurogu was divided into 2,204 scale standard grids of 100 m×100 m. Hourly PM_2.5 concentrations were modeled by the inverse distance weight method using 24 sensor-based air monitoring instruments. Hourly dynamic population distribution was evaluated according to gender and age using mobile phone network data and time-activity patterns. Results: Compared to before, the population exposure to PM_2.5 decreased after the outbreak of COVID-19. The concentration of PM_2.5 after the outbreak of COVID-19 decreased by about 41% on average. The variation of dynamic population before and after the outbreak of COVID-19 decreased by about 18% on average. Conclusions: Comparing before and after the outbreak of COVID-19, the population exposures to PM_2.5 decreased by about 40%. This can be explained to suggest that changes in people's activity patterns due to the outbreak of COVID-19 resulted in a decrease in exposure to PM_2.5.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.42.1-42
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• 2002

A model to predict population by sex, age and district over a long-range period is proposed based on fuzzy theories. First, a fuzzy model is described. Second, a method to estimate the social increase by sex and age in each district is proposed based on a fuzzy clustering method for dealing with long-range socioeconomic changes in population migration. By the proposed methods, it became possible to predict the population by sex, age and district over a long-range period. Third, the structure and characteristics of the three models of employment model, time distance model, and land use model constructed to predict various socioeconomic indicators, which are require...

• Journal of the Korean Association of Geographic Information Studies
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• v.9 no.4
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• pp.204-214
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• 2006

The necessity of a management for a metropolitan has long intrigued many urban scholars and researchers who are interested in Busan metropolitan spatial structure and its problems. The purpose of this study is to investigate the dynamic changes of spatial structure in Busan Metropolitan by analyzing the population, employment and Land prices, for the period of 1993, 2001. The major results in this study are as follows; While main-centers have experienced significant loss of population, sub-centers have been growing. Jung-Ang Dong still has high accessibility in population potentials, but its accessibility has declined since 1993. Pu-Jeon Dong had increasing trend of population until 2000, but its population has also descended since that time. Meanwhile, the population of sub-centers has increased in its accessibility. And The spatial pattern of the population in Busan has changed from monocentric to polycentric. This phenomenon was almost spontaneously generated from population dispersion from existing main-centers. In terms of change of land values are there is a spatial and temporal rhythm in the urbanization of Busan. The highest land value in Busan is shown in CBD. The development of Busan proceeded along the north-south belt and extended to west Busan.

• Journal of the Korean Society of Industry Convergence
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• v.5 no.1
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• pp.53-64
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• 2002

The purpose of this study was to predict the future urban activities effectively and rationally. For the purpose, a simulation model, based on SD, was built by integrating economic activities, land use and traffic of a city and by dividing Daegu Metropolitan City into seven districts and one county. To identify the effect of the development of a new city in the Dalsung County area, the future population and traffic volume of the city were predicted, using the model. The results are summarized as follows. The future population according to the development of a new city in the Dalsung County area was predicted, and the effects before and after the development twenty years later were compared. The future population of the Dalsung County was found to have slightly increased, whereas that of the adjoining Dalsuh Metropolitan District was found to has slightly decreased. For the other districts, there were no changes of the future population. It was found, therefore, that the development of a new city would have no effect on other districts. Then, the traffic volume according to the development of a new city in the Dalsung County area was also predicted. It was found that in the initial stage the traffic volume would increase with the increase in population of Dalsung County. It was predicted that particularly,. the traffic volume for the purpose of business would greatly increase. The traffic volume of Dalsuh Metropolitan District showed a slight decrease, whereas for the other districts, there were no changes of the traffic volume.

• Korea journal of population studies
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• v.8 no.1
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• pp.65-86
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• 1985

Korean population is ecpected to reach about 50 million by year 2000. And per capita GNP might attain the $5,000 level. This is bound to have profound impact on housing. For one thing, population and income growth will accelerate new household formation thus increasing new housing needs. On the other, changes in the housing preference function in association with income growth and new way of life would mean increasing demand for better dwelling environment. In addition, by year 2000, there will be many more elderly households necessitating new approaches to housing. The question is whether or not Korea could cope with new housing perspectives. If Korean housing has made in the past some progress in housing quality, it has not been able to tackle the mounting housing shortage. This is attributable to the concentration of effective housing demand in the hands of upper income groups in association with skewed income distribution and sustained dwelling price hike. Korea needs some basic changes in housing policy. The public sector should produce much more small dwellings either for sales or renting. Second, mortgage loans should be expanded so as to increase the access to housing. Third, every thing must be done to cut down the dwelling price through tax cut, relaxation of some requlations, cyclical stabilization of dwelling construction and loan subsidies.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.667-672
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• 2007

Land-use in Cheongju region is changing rapidly because of the increased interactions of human activities with the environment as population increases. We used multi-temporal Landsat images (1991 and 2000) and DEM data in a post-classification analysis with GIS to map land-use distribution and to analyse factors influencing the land-use changes for Cheongju City. Land-use statistics revealed that substantial land-use changes have taken place and that the built-up areas have expanded by about $17.57km^2(11.47%)$ over the study period (1991-2000). Agricultural lands and forests have decreased substantially while urban and barren lands have been on the increase. Rapid economic developments together with the increasing population were noted to be the major factors influencing rapid land use changes. Urban expansion has replaced urban and barren lands, thereby affecting habitat quality and leading to serious environmental degradation.