• 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.

• Korean Journal of Organic Agriculture
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• v.15 no.3
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• pp.291-307
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• 2007

The objective of this article is to examine the structure of the composition of the population in rural area for the last 45 years, and to forecast mid and long term structure of the population in the near future. Moreover, forecast has been done whether the rapid increase by the inflow of foreigners has any offset on the structural change in rural population. According to the research result, the rural area is experiencing a rapid decrease in population, a rapid increase in the percentage of the aged, and foreigners. To resolve the problematic situation mentioned above, some effective counterplan has to be considered by all agencies concerned.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.2
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• pp.335-352
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• 2023

When solving multi-objective optimization problems, the blindness of the evolution direction of the population gradually emerges with the increase in the number of objectives, and there are also problems of convergence and diversity that are difficult to balance. The many- objective optimization problem makes some classic multi-objective optimization algorithms face challenges due to the huge objective space. The sine cosine algorithm is a new type of natural simulation optimization algorithm, which uses the sine and cosine mathematical model to solve the optimization problem. In this paper, a knee-driven many-objective sine-cosine algorithm (MaSCA-KD) is proposed. First, the Latin hypercube population initialization strategy is used to generate the initial population, in order to ensure that the population is evenly distributed in the decision space. Secondly, special points in the population, such as nadir point and knee points, are adopted to increase selection pressure and guide population evolution. In the process of environmental selection, the diversity of the population is promoted through diversity criteria. Through the above strategies, the balance of population convergence and diversity is achieved. Experimental research on the WFG series of benchmark problems shows that the MaSCA-KD algorithm has a certain degree of competitiveness compared with the existing algorithms. The algorithm has good performance and can be used as an alternative tool for many-objective optimization problems.

• Journal of Korean Society of Rural Planning
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• v.28 no.4
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• pp.1-9
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• 2022

Rural decline due to the decrease of the local population is an inevitable phenomenon, and a vicious cycle has been formed between a lack of basic living services and a population decrease in rural areas. Therefore, the study aims to derive the migration decision-making characteristics based on basic living service infrastructure data in rural areas. To do this, the population change over the past 20 years was categorized into six types, and the relationship between the classified population change types and the number of basic living service infrastructures was analyzed using decision tree analysis. Of the total 3,501 regions, 801 regions were the continuous decline type, of which 740 were rural areas. On the other hand, among 569 regions that were the continuous increase type, 401 regions were urban areas, confirming the population imbalance between rural and urban areas. As a result of the decision tree analysis on the relationship between population change types and the distribution of basic living service infrastructure, the number of daycare centers was derived as an important variable to classify the continuous increase type. Hospitals, parks, and public transportation were also found to be major basic living services affecting the classification of population change types.

• The Korean Journal of Food & Health Convergence
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• v.9 no.5
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• pp.1-5
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• 2023

As the elderly population is rapidly increasing not only domestically but also globally, convenience foods for the elderly population are receiving attention. Therefore, the senior food market continues to grow rapidly both domestically and overseas. In relation to this, this study seeks to explore convenience food preferences through the growth status of the convenience food market and the demand for convenience food among the elderly population. We would like to consider various factors that influence the increase in convenience food consumption among the elderly population. This study uses meta-analysis and systematic literature research to find ways to revitalize the convenience food market targeting the elderly population. As a result of the analysis, it was mentioned that in order to revitalize the convenience food market for the elderly population, it is important to develop products with high nutritional value, suitable for the physical characteristics of the elderly population, and low price, and to consider convenience and accessibility. Through a multifaceted approach, we aim to increase the need for convenient food products that meet the needs of the elderly population, contribute to improving the health and well-being of the elderly, and further efficiently manage the health of the elderly nationally and globally.

• 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.

• Analyses & Alternatives
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• v.4 no.2
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• pp.71-102
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• 2020

This study analyzes the effect of demographic changes on economic growth. We use the supply-side output identity to forecast the growth potential of the Korean economy. According to the results, even based on optimistic assumptions and prospects, the economic growth rate is likely to fall drastically starting in 2020. Of course, to maintain growth potential, efforts to increase productivity are necessary. However, given the historical experience of developed countries, it is not clear whether the huge trend of demographic change can be offset by efforts to increase productivity. In the so-called '30-50 club' countries, both labor productivity and growth rate tend to fall after reaching the per capita income of $30,000. The degree of decline in the growth rate is closely related to changes in the working age population and the prime-age workforce. The results are similar when tracking the path of changes in total factor productivities of the economy. When a certain level of income is reached, the increase in total factor productivity also tends to slow down. The ripple effects of rapid changes in demographics will indeed be extensive. The negative impact is likely to be concentrated at a time when the working age population, the prime-age workforce, and the total population shrink simultaneously. Above all, it is necessary to use the government's fiscal space to block the possibility of a rapid fall in the growth rate. In addition, it is important to continuously implement various reform tasks that should be promoted, such as improving the education system and strengthening the social safety net.

• Journal of Families and Better Life
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• v.26 no.1
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• pp.51-67
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• 2008

The study analyzes divorce rates in Korea and makes suggestions for the future research of divorce rates. Based on the data from Korea Statistical Information System (KOSIS) of the National Statistics Organization, trends for divorce rates change and the relations between divorce rates and macro environmental factors are analyzed. Macro environmental factors include socioeconomic factors such as, Korean War, Vietnam War, oil shock, IMP economic crisis and gross national income (GNI), whereas demographical factors include population structure, rates of female labor participation, and geographical location. The principle characteristics of divorce rates are as follows: 1) the Crude divorce rates (CDR) and the number of divorced had been increased from 1970 to 2004, then the trend changed to a decrease; 2) the slope of the change were the highest during 1998 to 2004 after the IMP economic crisis. The relations between socioeconomic factors are as follows: 1) during the war there was a small increase of CDR for a short period of time; 2) the economic crisis of the nation tend to increase the CDR, while the IMP economic crisis had a strong impact on an increase of CDR because of the interaction effect among the population structure, women's sex role changes as well as the level of standard of living. The increase in CDR from 1990 to 2000 can be explained partly by the population of baby Boomers passing through their marriage and divorce process. The number of population residing in the rural area and the middle class households, and the mobility of population also had an impact on the divorce rates changes. The recommendations for the future research were as follows: 1) the need to develop new divorce statistics that are based on a marriage cohort or a birth cohort because family behavior is a mixture of personal, social and political responses, and because CDR is not an accurate measure of divorce rate since it was influenced by population structure; 2) the need to include micro personal factors as well as macro social factors in a model to find an interaction effect between those variables.

• Journal of the Society of Disaster Information
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• v.16 no.3
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• pp.479-492
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• 2020

Purpose: The purpose of this study is to analyze the impact of regional characteristics on population movement on the Seoul metropolitan areas. Method: To this end, 66 basic entities in the Seoul metropolitan area were divided into three regions by analyzing the demographic movement data from 2010 to 2016 and the factors for determining population movement within and between regions were identified by applying a stepwise regression technique. Result: The major analysis confirmed that the increase in the number of apartments in all areas of the Seoul metropolitan area, the increase in the number of single-family homes, the increase in the number of employees, the increase in manufacturers, the growth rate of knowledge, culture, and leisure industries, the increase rate of GRDP, and the opening of new subway stations. In particular, the growth rate of the number of apartments, the growth rate of the knowledge, culture and leisure industries, the increase rate of GRDP, and the opening of new subway stations played a positive role in increasing population inflow. Conclusion: The result showed that by region, the growth rate of knowledge, culture and leisure industries contributed greatly to the inflow of population in the first region, and that the opening of new subway stations and the increase of GRDPs were the main factors. The increase in the number of apartments and subway stations were the main factors in the three areas.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.63-70
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• 2022

This study is to investigate that population change as a result of the decline in population has a correlation with a decrease in crime, with the change in the demographic composition by comparing with two models: model with growth in population and one with the decline in population. We collected demographic data for all cities in Korea from the 2010 Census to 2020 offered by the Korean Statistical Information Service, with crime data comprising serious reported crime events from the Korean Nation Police Agency through requesting data related to the total number of crimes at the same as the period of demographic data. This study can identify the impacts of demographic changes as a result of population change on crime change through a comparative analysis between areas with population growth and ones with population decline. We can confirm that there are differences in determinants of crime between areas with population increase and one with population decrease from the analysis of the impact of demographic change as a result of population change on crime change.