• KOREAN JOURNAL OF CROP SCIENCE
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• v.37 no.4
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• pp.320-328
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• 1992

The soybean yield forcasting models based on climatic elements in six locations were estimated by the STEPWISE/MAXR, Cp statistics and GLM procedure of SAS. The climatic elements were aerial temperature, sunshine hours and precipitation from May to October in 20 years. The investigated six locations were Chunchon, Suwon, Cheongju, Kwangju, Iri and Jinju. The important climatic elements for main effects in Chunchon model were August sunshine hours-linear term, August precipitation-quadratic. June temperature to August precipitation and May temperature to August precipitation were interaction terms. The quadratic August precipitation was assumed to be related to yield in Chunchon. The main effects of Suwon were linear-June temperature, quadratic June sunshine hours and June precipitation. These terms affected yields negatively. The main effects of Cheongju were linear June temperature and quadratic August precipitation. May temperature to June precipitation, July to August precipitations were interactions. The main effects of Kwangju were linear July precipitation, quadratic June temperature and July precipitation. June to July sunshine hours of interaction terms influenced yield negatively. The main effects of Iri were linear May sunshine hours, quadratic May and July sunshine hours. May temperature to May precipitation and June to July precipitations affected yields negatively. The main effects of Jinju were linear June and August precipitations. August temperature to August sunshine hours, June sunshine hours to July precipitation and June to August precipitation were interactions. In linear terms, June and August precipitations and, in interactions, August to August sunshine hours were negative efficacies respectively. The included year variables in Chunchon, Suwon, Kwangju, and Jinju model building were recognized as a linear trend based on an assumption that the technological factors have improved through times.

• Journal of Korean Society of Forest Science
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• v.109 no.3
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• pp.259-270
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• 2020

Extreme weather events, such as heat and drought, have occurred frequently over the past two decades. This has led to continuous reports of cases of forest damage due to physiological stress, not pest damage. In 2014, pine trees were collectively damaged in the forest genetic resources reserve of Sogwang-ri, Uljin, South Korea. An investigation was launched to determine the causes of the dieback, so that a forest management plan could be prepared to deal with the current dieback, and to prevent future damage. This study aimedto 1) understand the topographic and structural characteristics of the area which experienced pine tree dieback, 2) identify the main causes of the dieback, and 3) predict future risk areas through the use of machine-learning techniques. A model for identifying risk areas was developed using 14 explanatory variables, including location, elevation, slope, and age class. When three machine-learning techniques-Decision Tree, Random Forest (RF), and Support Vector Machine (SVM) were applied to the model, RF and SVM showed higher predictability scores, with accuracies over 93%. Our analysis of the variable set showed that the topographical areas most vulnerable to pine dieback were those with high altitudes, high daily solar radiation, and limited water availability. We also found that, when it came to forest stand characteristics, pine trees with high vertical stand densities (5-15 m high) and higher age classes experienced a higher risk of dieback. The RF and SVM models predicted that 9.5% or 115 ha of the Geumgang Pine Forest are at high risk for pine dieback. Our study suggests the need for further investigation into the vulnerable areas of the Geumgang Pine Forest, and also for climate change adaptive forest management steps to protect those areas which remain undamaged.

• Korea Real Estate Review
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• v.28 no.1
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• pp.79-90
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• 2018

The purpose of this study was to estimate the pricing factors of residential lands in new cities by estimating the pricing model of residential lands. For this purpose, hedonic equations for each quantile of the conditional distribution of land prices were estimated using quantile regression methods and the sale price date of Jangyu New Town in Gimhae. In this study, a quantile regression method that models the relation between a set of explanatory variables and each quantile of land price was adopted. As a result, the differences in the effects of the characteristics by price quantile were confirmed. The number of years that elapsed after the completion of land construction is the quadratic effect in the model because its impact may give rise to a non-linear price pattern. Age appears to decrease the price until certain years after the construction, and increases the price afterward. In the estimation of the quantile regression, land age appears to have a statistically significant impact on land price at the traditional level, and the turning point appears to be shorter for the low quantiles than for the higher quantiles. The positive effects of the use of land for commercial and residential purposes were found to be the biggest. Land demand is preferred if there are more than two roads on the ground. In this case, the amount of sunshine will improve. It appears that the shape of a square wave is preferred to a free-looking land. This is because the square land is favorable for development. The variables of the land used for commercial and residential purposes have a greater impact on low-priced residential lands. This is because such lands tend to be mostly used for rental housing and have different characteristics from residential houses. Residential land prices have different characteristics depending on the price level, and it is necessary to consider this in the evaluation of the collateral value and the drafting of real estate policy.

• Korean small business review
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• v.31 no.4
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• pp.67-93
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• 2009

The purpose of this paper is to explore the relations between financial constraints and dividend smoothing of innovative small and medium sized enterprises(SMEs) listed on Korea Securities Market and Kosdaq Market of Korea Exchange. The innovative SMEs is defined as the firms with high level of R&D intensity which is measured by (R&D investment/total sales) ratio, according to Chauvin and Hirschey (1993). The R&D investment plays an important role as the innovative driver that can increase the future growth opportunity and profitability of the firms. Therefore, the R&D investment have large, positive, and consistent influences on the market value of the firm. In this point of view, we expect that the innovative SMEs can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. And also, we expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Aivazian et al.(2006) exert that the financial unconstrained firms with the high accessibility to capital market can adjust dividend payment faster than the financial constrained firms. We collect the sample firms among the total SMEs listed on Korea Securities Market and Kosdaq Market of Korea Exchange during the periods from January 1999 to December 2007 from the KIS Value Library database. The total number of firm-year observations of the total sample firms throughout the entire period is 5,544, the number of firm-year observations of the dividend firms is 2,919, and the number of firm-year observations of the non-dividend firms is 2,625. About 53%(or 2,919) of these total 5,544 observations involve firms that make a dividend payment. The dividend firms are divided into two groups according to the R&D intensity, such as the innovative SMEs with larger than median of R&D intensity and the noninnovative SMEs with smaller than median of R&D intensity. The number of firm-year observations of the innovative SMEs is 1,506, and the number of firm-year observations of the noninnovative SMEs is 1,413. Furthermore, the innovative SMEs are divided into two groups according to level of financial constraints, such as the financial unconstrained firms and the financial constrained firms. The number of firm-year observations of the former is 894, and the number of firm-year observations of the latter is 612. Although all available firm-year observations of the dividend firms are collected, deletions are made in the case of financial industries such as banks, securities company, insurance company, and other financial services company, because their capital structure and business style are widely different from the general manufacturing firms. The stock repurchase was involved in dividend payment because Grullon and Michaely (2002) examined the substitution hypothesis between dividends and stock repurchases. However, our data structure is an unbalanced panel data since there is no requirement that the firm-year observations data are all available for each firms during the entire periods from January 1999 to December 2007 from the KIS Value Library database. We firstly estimate the classic Lintner(1956) dividend adjustment model, where the decision to smooth dividend or to adopt a residual dividend policy depends on financial constraints measured by market accessibility. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between current payout rato and target payout ratio each year. In the Lintner model, dependent variable is the current dividend per share(DPS_t), and independent variables are the past dividend per share(DPS_t-1) and the current earnings per share(EPS_t). We hypothesized that firms adjust partially the gap between the current dividend per share(DPS_t) and the target payout ratio(Ω) each year, when the past dividend per share(DPS_t-1) deviate from the target payout ratio(Ω). We secondly estimate the expansion model that extend the Lintner model by including the determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory. In the expansion model, dependent variable is the current dividend per share(DPS_t), explanatory variables are the past dividend per share(DPS_t-1) and the current earnings per share(EPS_t), and control variables are the current capital expenditure ratio(CEA_t), the current leverage ratio(LEV_t), the current operating return on assets(ROA_t), the current business risk(RISK_t), the current trading volume turnover ratio(TURN_t), and the current dividend premium(DPREM_t). In these control variables, CEA_t, LEV_t, and ROA_t are the determinants suggested by the residual dividend theory and the agency theory, ROA_t and RISK_t are the determinants suggested by the dividend signaling theory, TURN_t is the determinant suggested by the transactions cost theory, and DPREM_t is the determinant suggested by the catering theory. Furthermore, we thirdly estimate the Lintner model and the expansion model by using the panel data of the financial unconstrained firms and the financial constrained firms, that are divided into two groups according to level of financial constraints. We expect that the financial unconstrained firms can adjust dividend payment faster than the financial constrained firms, because the former can finance more easily the investment funds through the market accessibility than the latter. We analyzed descriptive statistics such as mean, standard deviation, and median to delete the outliers from the panel data, conducted one way analysis of variance to check up the industry-specfic effects, and conducted difference test of firms characteristic variables between innovative SMEs and noninnovative SMEs as well as difference test of firms characteristic variables between financial unconstrained firms and financial constrained firms. We also conducted the correlation analysis and the variance inflation factors analysis to detect any multicollinearity among the independent variables. Both of the correlation coefficients and the variance inflation factors are roughly low to the extent that may be ignored the multicollinearity among the independent variables. Furthermore, we estimate both of the Lintner model and the expansion model using the panel regression analysis. We firstly test the time-specific effects and the firm-specific effects may be involved in our panel data through the Lagrange multiplier test that was proposed by Breusch and Pagan(1980), and secondly conduct Hausman test to prove that fixed effect model is fitter with our panel data than the random effect model. The main results of this study can be summarized as follows. The determinants suggested by the major theories of dividend, namely, residual dividend theory, dividend signaling theory, agency theory, catering theory, and transactions cost theory explain significantly the dividend policy of the innovative SMEs. Lintner model indicates that firms maintain stable and long run target payout ratio, and that firms adjust partially the gap between the current payout ratio and the target payout ratio each year. In the core variables of Lintner model, the past dividend per share has more effects to dividend smoothing than the current earnings per share. These results suggest that the innovative SMEs maintain stable and long run dividend policy which sustains the past dividend per share level without corporate special reasons. The main results show that dividend adjustment speed of the innovative SMEs is faster than that of the noninnovative SMEs. This means that the innovative SMEs with high level of R&D intensity can adjust dividend payment faster than the noninnovative SMEs, on the ground of their future growth opportunity and profitability. The other main results show that dividend adjustment speed of the financial unconstrained SMEs is faster than that of the financial constrained SMEs. This means that the financial unconstrained firms with high accessibility to capital market can adjust dividend payment faster than the financial constrained firms, on the ground of their financing ability of investment funds through the market accessibility. Futhermore, the other additional results show that dividend adjustment speed of the innovative SMEs classified by the Small and Medium Business Administration is faster than that of the unclassified SMEs. They are linked with various financial policies and services such as credit guaranteed service, policy fund for SMEs, venture investment fund, insurance program, and so on. In conclusion, the past dividend per share and the current earnings per share suggested by the Lintner model explain mainly dividend adjustment speed of the innovative SMEs, and also the financial constraints explain partially. Therefore, if managers can properly understand of the relations between financial constraints and dividend smoothing of innovative SMEs, they can maintain stable and long run dividend policy of the innovative SMEs through dividend smoothing. These are encouraging results for Korea government, that is, the Small and Medium Business Administration as it has implemented many policies to commit to the innovative SMEs. This paper may have a few limitations because it may be only early study about the relations between financial constraints and dividend smoothing of the innovative SMEs. Specifically, this paper may not adequately capture all of the subtle features of the innovative SMEs and the financial unconstrained SMEs. Therefore, we think that it is necessary to expand sample firms and control variables, and use more elaborate analysis methods in the future studies.

• Journal of agricultural medicine and community health
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• v.11 no.1
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• pp.44-54
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• 1986

This study was aimed at investigating the health seeking behaviors of patients; For the purpose of analyzing the research theme we classified the study into two phase. First, the types of patients' health seeking behavior were categorized into a scheme according to what medical care resources were utilized in patients' coping process. Second, from patients' first visits to third visits to medical resources, we analyzed variations of factors which noted as crucial elements in constituting the patients' sickness career. To grasp the generalized characteristics from complicated empirical data, we limited the scope of our analysis to third stage of health seeking. A total of 121 persons who had beer suffering from chronic diseases more than 3 months was sampled among the residents of Banwol-Eup, the target Area of Korea University Health Project. The findings are as follows ; 1) In the course of visiting medical care resources, 34 different types of health seeking Behavior were found. From this result we inferred the idea that patients in Banwol-Eup had not any stable norms to cope with their pains. Clinics, hospital, pharmacy, Herb-doctors', folkways (self-treatment) were accessed by patients in orders. But more than half of patients who had utilized clinics or hospitals from their first to third visits, changed medical care resources to others, for example herb doctors or folkways, which had fundamentally different treatment models. Upon these two facts, the diversified types and capricious patterns in the health seeking behavior of Banwol patients, we observed a typical Shopping-Around phenomenon. 2) Factors which influenced patients' to their sickness career were changed along the courses of health seeking, from first to third visits as follows ; $\cdot$ Perceived seriousness of diseases were tended to decrease. $\cdot$ Professional medical personnel tended to be influencial in the patients' sickness career, (5.0%, 25.0% and 65.7%). The influence of the primary interaction groups such as parents, friends, neighbours, tended to decrease ; (90.9%, 71.2% and 30.0%). $\cdot$ The subjective reasons why to choose such a medical care resource were related to economic affordability and disease-itself as main motives. Credibility of health resources tended to increase 14.9%, 24.0% and 31.4 sequently. $\cdot$ Geographic accessibility factors did not change significantly. Most of patients had utilized health resources in Banwol and Anyang area. 3) Cultural inclination in the shopping-around phenomenon has shown difference among age groups. The age group' over 50 years' preferred traditional health resources to modern health resources. 4) Consistency of health seeking behavior on the shopping around phenomenon has shown difference according to the degrees of patients' economic affordability and those of psychological satisfaction toward modern health services. However, there were some restrictions in this thesis ; a) the study was limited to the 3rd health seeking career so it did not allow us to collect more informations after that, b) the study was not able to carry out causal analysis on patients health behavior determinated by explanatory model of health resources, and c) the study was not able to take into consideration of factors connected with social structural circumstances. Despite of restrictions described above, we are sure that this thesis would promote health providers' understanding toward patients' inclinations, through which they could provide efficient and accurate medical service.

• Atmosphere
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• v.21 no.4
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• pp.349-359
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• 2011

The climatology in stratospheric ozone over the Korean Peninsula, presented in previous studies (e.g., Cho et al., 2003; Kim et al., 2005), is updated by using daily and monthly data from satellite and ground-based data through December 2009. In addition, long-term satellite data [Total Ozone Mapping Spectrometer (TOMS), Ozone Monitoring Instrument (OMI), 1979~2009] have been also analyzed in order to deduce the spatial distributions and temporal variations of the global total ozone. The global average of total ozone (1979~2009) is 298 DU which shows a minimum of about 244 DU in equatorial latitudes and increases poleward in both hemispheres to a maximum of about 391 DU in Okhotsk region. The recent period, from 2006 to 2009, shows reduction in total ozone by 6% relative to the values for the pre-1980s (1979~1982). The long-term trends were estimated by using a multiple linear regression model (e.g., WMO, 1999; Cho et al., 2003) including explanatory variables for the seasonal variation, Quasi-Biennial Oscillation (QBO) and solar cycle over three different time intervals: a whole interval from 1979 to 2009, the former interval from 1979 to 1992, and the later interval from 1993 to 2009 with a turnaround point of deep minimum in 1993 is related to the effect of Mt. Pinatubo eruption. The global trend shows -0.93% $decade^{-1}$ for the whole interval, whereas the former and the later interval trends amount to -2.59% $decade^{-1}$ and +0.95% $decade^{-1}$, respectively. Therefore, the long-term total ozone variations indicate that there are positive trends showing a recovery sign of the ozone layer in both North/South hemispheres since around 1993. Annual mean total ozone (1985~2009) is distributed from 298 DU for Jeju ($33.52^{\circ}N$) to 352 DU for Unggi ($42.32^{\circ}N$) in almost zonally symmetric pattern over the Korean Peninsula, with the latitudinal gradient of 6 DU $degree^{-1}$. It is apparent that seasonal variability of total ozone increases from Jeju toward Unggi. The annual mean total ozone for Seoul shows 323 DU, with the maximum of 359 DU in March and the minimum of 291 DU in October. It is found that the day to day variability in total ozone exhibits annual mean of 5.7% in increase and -5.2% in decrease. The variability as large as 38.4% in increase and 30.3% in decrease has been observed, respectively. The long-term trend analysis (e.g., WMO, 1999) of monthly total ozone data (1985~2009) merged by satellite and ground-based measurements over the Korean Peninsula shows increase of 1.27% $decade^{-1}$ to 0.80% $decade^{-1}$ from Jeju to Unggi, respectively, showing systematic decrease of the trend magnitude with latitude. This study also presents a new analysis of ozone density and trends in the vertical distribution of ozone for Seoul with data up to the end of 2009. The mean vertical distributions of ozone show that the maximum value of the ozone density is 16.5 DU $km^{-1}$ in the middle stratospheric layer between 24 km and 28 km. About 90.0% and 71.5% of total ozone are found in the troposphere and in the stratosphere between 15 and 33 km, respectively. The trend analysis reconfirms the previous results of significant positive ozone trend, of up to 5% $decade^{-1}$, in the troposphere and the lower stratosphere (0~24 km), with negative trend, of up to -5% $decade^{-1}$, in the stratosphere (24~38 km). In addition, the Umkehr data show a positive trend of about 3% $decade^{-1}$ in the upper stratosphere (38~48 km).

• Journal of the Korean Applied Science and Technology
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• v.36 no.4
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• pp.1472-1484
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• 2019

This study aimed to verify the effects of nutritional status, K-ADL, K-IADL, and social network on the life satisfaction of the elderly in home. Total 213 research subjects participated in this study, and their average age was 71.38±5.59. As the methods of analysis, using the SPSS 21.0, this study examined the differences between variables in accordance with the general characteristics, and then verified the correlations between independent variables of nutritional status, K-ADL, K-IADL, social network(family networks, friends networks), and life satisfaction. In order to verify the factors having effects on the life satisfaction of the elderly in home, the stepwise multiple regression analysis was conducted. In the results of this study, in the general characteristics, the life satisfaction showed statistically significant differences in accordance with education(F=5.280, p=.002), economic condition(F=22.407, p<.001), monthly income(F=3.181, p=.015), and subjective health status(F=14.933, p<.001). In the results of verifying the correlation between independent variables, the life satisfaction showed positive correlations with family networks(r=268, p<.001) and friends networks(r=.286, p<.001) while the nutritional status(r=-.222, p=.001), K-IADL(r=-.235, p=.001), and interdependent social support(r=-.283, p<.001) showed negative correlations. The predictive factors on the life satisfaction of the elderly in home included the economic condition(β=.358, p<.001), subjective health status(β=.245, p<.001), interdependent social support(β=-.158, p=.009), and K-IADL(β=-.153, p=.012), and the explanatory power was 30.1%. The regression model was statistically significant(F=23.778, p<.001). Based on such results of this study, it would be necessary to develop programs that could maintain and improve the health of the elderly, and also provide financial support to the elderly suffering from economic hardship, in order to improve the life satisfaction of the elderly in home. Moreover, there should be the concrete measures for vitalizing the community-connected activities for interdependent social support.

• Journal of Korean Society of Forest Science
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• v.82 no.4
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• pp.420-430
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• 1993

This study was conducted to investigate the effect of the forest environmental factors(5 items) and physico-chemical properties of soil(13 items) on the growth of Pinus thunbergii stands. The 218 plots were sampled over the coastal district of the whole country. In statistical analysis, the explanatory variables were soil and environmental factors(18 items), and the response variable was the site index of Pinus thunbergii stands. Data computation was processed in order of preparation of original data, computation of inner correlation matrix table by correlation analysis, calculation of partial correlation coefficients and coefficients of determination, estimation of regression equation by stepwise begression analysis, and stepwise regression analysis by factor score of factor analysis. The main results obtained were summarized as follows ; 1. The site index in Pinus thunbergii stands way highly correlated with effective soil depth(r=0.8668), slope percentage, organic matter, and total nitrogen. 2. According to the coefficients by partial correlation analysis, effective soil depth(r=0.6270), slope percentage (r=-0.5423) and base saturation(r=0.3278) among environmental factors had a great effect on tree growth. 3. With stepwise regression analysis, the factors effecting on the Pinus thunbergii stands growth were effective soil depth, slope percentage, organic matter, base saturation, soil pH, content of silt, exchangeable Ca, and etc. 4. Estimation equation for the site index of Pinus thunbergii stands was given by $Y=13.2691+0.0242\;X_2-1.2244\;X_4+0.6142\;X_5-0.3472\;X_{11}+0.0355\;X_{13}+0.1552\;X_{15}-0.1002\;X_{17}$. The coefficient of determination for the estimation model was 0.77, which was significant at the 1 percent level. 5. In result of factor analysis by the environmental factors, principal components were 6 factors, and communality contribution percentage was 71.1 percent. 6. By stepwise regression analysis between factor score and site index of Pinus thunbergii stands, the factor group effecting on site index was 5 principal components. The coefficients of determination was 85 percent, which was significant at the 1 percent level. In conclusion, on the occasion of analizing which factors to effect on the tree height growth in Pinus thunbergii stands the stepwise regression analysis proved to be greatly significant. Also the management of Pinus thunbergii stands should be working by the above selected growth factors.

• Journal of Society of Preventive Korean Medicine
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• v.5 no.1
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• pp.41-56
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• 2001

Overview: The purpose of this study was to evaluate the determinants on the correlation between constitution and health promoting lifestyle profile on the workers. Also, the questionnaire on the HPLP (health promoting lifestyle profile) of Walker(1987) and Sa-sang constitution of Lee(l894) were utilized Methods: Data from a representative sample of 652 workers were analyzed Pearson's chi-square test analysis was utilized to test the explanatory causal model and to determine the direct and indirect effects of independent variables on quality of life. Results: Constitutional distribution among exposed group, were Tae-eum In(43.7%), So-eum In(33.6%), and So-yang In(22.7%). The degree of the subjects practicing health promoting lifestyle, on a scale of 1 to 4, is an average of 2.62, personal relations 2.94, self-realization 2.86, stress management 2.71, nutrition 2.68, responsibility for health 2.37, and exercise 2.21, with personal relations earning the highest points and exercise the lowest As for factors influencing health promoting lifestyle, there is significant difference between sex and age. That is female and higher age. On the difference between constitution and health promoting lifestyle, Tae-eum In is the highest all area except personal relations. So-eum In is the lowest all area except responsibility for health. Conclusions: Tae-eum In totally do health promoting lifestyle well but So-eum In relatively not. On the Study we used the HPLP(health promoting lifestyle profile) on the premise that each person's daily life, the attitude and the practice level to the health have an influence on the health. So in the constitution there is a little differences in the consideration and the practice level and health condition will be different. On this study we finish up by knowing about the health promoting lifestyle. But on next time we will have to go on studying about the sign and the comparison with the result of western and oriental medical health examination to the each constitution on carrying out continuously oriental medical health examination.

• Journal of agricultural medicine and community health
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• v.46 no.4
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• pp.280-294
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• 2021

Objectives: The purpose of this study is to investigate the effects of social capital characteristics, socio-demographic characteristics, physical condition, and health behavior characteristics on health-related quality of life of the elderly in Korea. Methods: T-test, one-way ANOVA, and regression analysis were performed by applying a complex sample design to 57.787 people aged 65 and over using the 2019 Community Health Survey. Results: First, as a result of complex-sample T-test and ANOVA analysis, it was found that there were differences in health-related quality of life according to social capital characteristics, physical condition & health behavior characteristics, and socio-demographic characteristics. Complex Sample Regression Analysis Results, the explanatory power of the model was 28%. When living in the metropolitan area, living in an apartment building, having a spouse, having a higher household income, economic activity, higher educational attainment, increase sleeping time, walking time, frequent binge drinking, health checkup, networking, trust, and social participation showed higher health-related quality of life. When people were older, their gender was female, higher BMI, number of chronic diseases, and severe stress that showed lower health-related quality of life. Conclusions: It was proved that the factors affecting the health-related quality of life of the elderly are not only physical condition and health behavior factors, but also social capital and socio-demographic characteristics. It was found that the role as a member was important.