• Journal of the Optical Society of Korea
• /
• v.15 no.1
• /
• pp.68-73
• /
• 2011

This study investigated, using the Orbscan II topography system, the influence of age and sex related changes on the corneal thickness and anterior corneal curvature, more specifically the fine structure of the cornea, in a Korean young population. The Orbscan II topography system is a computer-assisted slit-beam scanning technology that can map the anterior section of the cornea. The mean central corneal thickness of all subjects was $547.532{\pm}44.529\;{\mu}m$. There was no statistical difference (p>0.5) in the mean central corneal thickness between males and females. Sex and age related changes in the mean central corneal thickness had no specific statistical difference (P>0.5). There was a negative correlation between the anterior corneal curvature and the central corneal thickness in all subjects, except for the twenty year olds. However, the thickness relationship between the mean central corneal and the eight paracentral corneal thicknesses had strong statistical differences in all subjects. Also age and sex related changes in the central corneal thickness and the anterior corneal curvature in all subjects had no statistically significant difference, except from 20-26 years old (p>0.05). This information could be a suitable reference basis for future studies in the young population of Asia and for the development of examination tools for corneal refractive surgery.

• Journal of Ecology and Environment
• /
• v.29 no.1
• /
• pp.1-16
• /
• 2006

Environmental variables, fishing and biological data of the common squid, Todarodes pacificus were used to describe changes in structure, migration and abundance of the squid population in relation to ocean climate shifts. It was possible to consider the main groups of the squid (autumn and winter-spawned groups) as a single population to aid conservation in the waters around Korea and Japan (TWC and KOC regions). The patterns of yearly fluctuations in abundance of the squid population in the two regions were the same during 52 years of $1952{\sim}2003$. The abundance of the squid began to decrease in both regions in the early 1970s, remained low in the 1980s and the main squid groups synchronously increased in the 1990s coincident with favorable changes of thermal conditions and plankton production in those ecosystems. The mechanisms of changes in the structure, distribution and abundance of common squid population in relation to current-mediated migration circuits are explained on the basis of phenological variables responding to climate shifts.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.46 no.4
• /
• pp.392-405
• /
• 2010

The population of small yellow croaker, Larimichthys polyactis, in the Yellow and East China Seas has decreased significantly since the mid 1970s. Several management measures have been introduced to conserve it, but population size remains low. To rebuild this population, it is now necessary to consider more effective management methods based on the stock assessment. To determine long-term population changes, fishery and biological data collected over 34 years (1969-2002) were analysed. Yearly fish length compositions were analysed for the time periods 1968 through 1970, 1978 through 1982, and 1993 through 2002; and catch data was available from 1969 to 2002. Annual population sizes were calculated based on length composition, the relationship between total length and body weight, and total landings. Analyses showed that since the 1970s, average size of harvested fish decreased; the proportion of less mature fish (smaller than the 50% maturity length, 19cm) in catches has increased and the estimated biomass has decreased significantly. Consequently, the main management recommendation is that juvenile fish need to be better protected to allow the rebuilding of resources to a more sustainable population level. This will require fish size limit, permissible mesh size, and closed area and season regulations.

• Korean System Dynamics Review
• /
• v.15 no.3
• /
• pp.37-59
• /
• 2014

This paper is to study dynamics of populations of religions. As human population is a crucial source of social dynamics, the religious population is a driving force that changes political and cultural landscape of society. Although many christian scholars have reported important causal factors in changing population of christian world, there are few studies on the dynamics of religious population in system dynamics. This paper interprets these dynamic mechanisms in terms of feedback loops and constructs a basic system dynamic model to forecast future trend of religious population in Korean society.

• Asia Marketing Journal
• /
• v.21 no.4
• /
• pp.77-89
• /
• 2020

Population-level learning has traditionally been used to provide an explanation for the underlying mechanism of industry change. But it has yet to examine the impact on strategic decisions such as market entry. This conceptual paper aims to provide an insight into how population-level learning affects entry likelihood by acting as a tool for interpreting population-level changes. We study this in the context of the fast-paced mobile gaming industry where population-level information is salient and develop a set of propositions with regard to the likelihood of entry.

• Journal of Environmental Health Sciences
• /
• v.50 no.1
• /
• pp.6-15
• /
• 2024

Background: People's activities have been restricted due to the COVID-19 pandemic. These changes in activity patterns may lead to a decrease in fine particulate matter (PM_2.5) concentrations. Additionally, the level of population exposure to PM_2.5 may be changed. Objectives: This study aimed to analyze the impact of population movement and meteorological factors on the distribution of PM_2.5 concentrations before and after the outbreak of COVID-19. Methods: The study area was Guro-gu in Seoul. The research period was selected as January to March 2020, a period of significant population movement changes caused by COVID-19. The evaluation of the dynamic population was conducted by calculating the absolute difference in population numbers between consecutive hours and comparing them to determine the daily average. Ambient PM_2.5 concentrations were estimated for each grid using ordinary kriging in Python. For the population exposure assessment, the population-weighted average concentration was calculated by determining the indoor to outdoor population for each grid and applying the indoor to outdoor ratio to the ambient PM_2.5 concentration. To assess the factors influencing changes in the ambient PM_2.5 concentration, a statistical analysis was conducted, incorporating population mobility and meteorological factors. Results: Through statistical analysis, the correlation between ambient PM_2.5 concentration and population movement was positive on both weekends and weekdays (r=0.71, r=0.266). The results confirmed that most of the relationships were positive, suggesting that a decrease in human activity can lead to a decrease in PM_2.5 concentrations. In addition, when population-weighted concentration averages were calculated and the exposure level of the population group was compared before and after the COVID-19 outbreak, the proportion of people exceeding the air quality standard decreased by approximately 15.5%. Conclusions: Human activities can impact ambient concentrations of PM_2.5, potentially altering the levels of PM_2.5 exposure in the population.

• Korea journal of population studies
• /
• v.11 no.1
• /
• pp.131-145
• /
• 1988

There was a rapid population change accompanied with changes in population structure recently in Korea. The changes were nationwide though greater in rural, where the population decreased steeply, through the internal migration from rural to urban. There, in the structure of Gun's population, severely distorted features have been shown in the study. Also, the structure differ greatly by Gun. It indicated that the rural problems were much more serious than anticipated when analyzed generally. It tells us that we should consider the problems related with different population structure in developing the programs for the rural.

• Korean Journal of Social Welfare
• /
• v.57 no.1
• /
• pp.271-297
• /
• 2005

Since the 1980s, the western welfare states have experienced a wide spectrum of socio-economic changes; changes in population composition, the economic globalization, the post-industrialization, an increasing flexibility in the labor market. etc. This study examines the trend of poverty in welfare states, and analyzes how those socio-economic changes are related to it. For these purposes, this study first calculates the poverty indices for several years in 10 welfare states using the Luxembourg Income Study database, and then decomposes the index by subpopulation and income sources. Major findings of this study can be summarized as follows. First of all, the welfare state in general has experienced an increasing trend in the degree of poverty since the 1980s. In particular, poverty has greatly intensified in the United Kingdom and the Netherlands. Many other welfare states including Canada, Germany, Sweden, and Norway have also experienced substantial increases in poverty. The increasing trend of poverty is not wholly due to changes in population composition such as increases in the aging population and one-parent(mother) families. Contrary to the traditional belief, these population groups are not as much poor as the working-age population. In particular, the degree of poverty in the elderly is less severe than in the working-age group. Furthermore, since the 1980s the market income poverty in the aging population has shown a decreasing trend in many welfare states. The degree and trend of poverty in one-parent families vary greatly across countries, owing to the labor market and income transfer policies. The most important reason for the increasing poverty trend in the welfare state is that the degree of poverty has been deepening in the working-age population. Especially, the market income poverty of the working-age population has considerably increased in every country except the Netherlands. Structural changes in the economy and the labor market may drive the increasing trend of poverty. Further studies and deliberate anti-poverty policies are needed to tackle the factors relating to the increase in the market income poverty.

• Land and Housing Review
• /
• v.9 no.3
• /
• pp.29-36
• /
• 2018

This study aims at suggesting directions to make children's parks considering the actual groups using them by comparative analysis of age distribution in residents within area of use and locations of children's parks with regards to changes in population structure of low birth rate and aging. Cheongju was selected for the study, and the current status of children's parks and population structure were categorized into six stages and the investigation and analysis were conducted by statistics by population group and by using Arc GIS Program. As a result of the analysis, children under 13 were 13.1% of the entire population in Cheongju and share of middle-aged and aged group including middle-aged was 31.3%. Park area per one children under 13 was 5.9㎡ and based on walking use area(250m), average number of parks available by autonomous district was eight. As a result of the analysis of characteristics of distribution of children's parks, they are densely located in old downtowns or the distribution density was relatively high in newly developed areas such as Osong-eup or Ochang-eup. However, outer rural areas have no children's parks or relatively low rate. As a result of the analysis on population structure and co-efficient of park location, in nine autonomous districts, aged group is increasing, leading to decrease use of children's parks. If resident rate aged group is higher in the region where a children's park is located, it is necessary to re-compose the existing one to different one or to change purposes of parks to be planned. Also, in the area with similar rates in both children's group and aged group, composing complex parks for both of them could be considered. This study has limitations by not conducting field studies about the current status of use of children's parks in areas where the population structure has been changing and not suggesting specifically new types of parks according to changes in population structure. It is necessary to conduct the following studies about relationship between children's parks and policies for composing parks responding to changes in population structure in neighboring regions in future.

• Journal of Korean Society of Rural Planning
• /
• v.9 no.4 s.21
• /
• pp.9-18
• /
• 2003

The objectives of the study are to improve techniques for social impact assessment and to suggest their measuring methods to apply in small scale rural development projects. Population, residence, industries, and traffic volumes were selected to measure the social and economic impact assessment of Seongeup agricultural water development project in Jeju Province. Existing data gathering methods were used to estimate the changes of population and traffic volumes. Interview schedule for villagers was applied to estimate the residents' satisfaction to living environments. Interview schedule for experts was applied to estimate agricultural productivity and land price. The results of social and economic impact assessment show that there will be considerable changes in living environments, agricultural productivity, and land price. On the contrary, the project will make little impacts on the changes of population, em-ployment, and traffic volumes.