• Clinical and Experimental Pediatrics
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• v.51 no.7
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• pp.747-753
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• 2008

Purpose : Diabetes mellitus is a major risk factor for the development of cardiovascular disease. Early atherosclerotic changes in the arterial walls begin in adolescence and the risk factors are associated with its development. To assess the usefulness of carotid artery intima-media thickness (IMT), as a marker of early atherosclerosis, we evaluated the structural and functional characteristics of the carotid artery and investigated their relationshop with the metabolic and anthropometric parameters in children and adolescents with type 1 diabetes. Methods : For this study, we enrolled 23 children with type 1 diabet and 19 age and sex-equivalent healthy children as the control group. Metabolic and anthropometric parameters such as serum lipid levels, plasma glycated hemoglobin (HbA1c), and body mass index were measured after a 12-h fasting period. The carotid artery IMT was measured by a high-quality ultrasound system, and compliance, and distensibility were calculated by an equation. Results : There were no significant differences between the 2 groups with regard to the sex ratio, age, blood pressure and serum cholesterol levels' however, HbA1c levels were significantly higher in the diabetic children ($8.5{\pm}1.8$ vs. $5.0{\pm}0.2$, P=0.001). Ultrasonographic findings showed that compared with the control group, the diabetic group had higher IMT ($0.45{\pm}0.06mm$ vs. $0.41{\pm}0.04mm$, P=0.04), but there were no significant differences in compliance and distensibility. The HbA1c (P=0.002) and high-density lipoprotein cholesterol (P=0.026) levels were independent IMT predictors in the diabetic group. Conclusion : Here, the carotid artery IMT was higher in the diabetic group, and it is correlated with atherosclerotic risk factor. Thus, carotid IMT could be evaluated as a marker of early atherosclerosis in diabetic children.

• Korean Journal of Soil Science and Fertilizer
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• v.10 no.3
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• pp.135-151
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• 1977

The present paper summerizes the studies on clay mineralogical characteristics of Korean soil, relationship between potassium and clay minerals, potassium release pattern of clay minerals and utilization of clay minerals for soil conditioner and fertilizers, which have been carried out in this laboratory. 1. The red yellow podzolic soil is mostly abundant in the upland of Korea and mainly consists of halloysite and weathered intermediates of mica such as illite and vermiculite. 2. With regard to soil parent material, kaolin mineral occurs abundant in soils derived from granite and granite gneiss. Mica is dominant in basaltic soil. The main clay mineral of the soil, originated from the Tertiary, is found montmorillonite and the volcanic soil of Jeju Island has plenty of allophane as its main clay mineral. 3. It is confirmed that the soil fertility depends on the composition of clay minerals. The red yellow podzolic soil, containing lot of kaolin, shows low productivity while the montmorillonite soil has higher productivity. 4. The release rate of solid phase potassium (micas and fixed potassium) follows the 1st order reaction equation in the equilibrium solution of $IN-NH_4OAc$. The potassium release constant is positively correlated with the mica content of the clay but negatively correlated with the content of $14.5{\AA}$ minerals. On the other hand, the potassium release constant has very high correlation with the ratio(Kex/Kt) of exchangeable potassium(Kex) to total potassium(Kt). 5. It is also found that Kex/Kt has rather high correlation with the content of mica and $14.5{\AA}$ minerals existed in the clay as well as the mica content of the soil.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.12
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• pp.1293-1303
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• 2006

This paper represents a comparison the difference between existence and nonexistence of soundproof trees for road traffic noise. Also we suggested that the simple equation has been derived using a single regression analysis for predicting levels of $Leq_{th}$ at a given distance from a road in terms of the flow rate, the mean speed of the traffic, and the percentage of the type vehicles in the existence and nonexistence of soundproof trees. We classified a vehicle into four and analyzed contribution rate to traffic volume. As a result, the order showed as followed: light vehicle>medium vehicle>heavy vehicle>motorcycle. However, the results of analyzing contribution rate with between traffic volume and traffic noise by the each type showed as followed; Motorcycle>Light vehicle>Medium vehicle>Heavy vehicle. This study showed that the most a lof of traffic volumes of the three vehicles(light vehicle, medium vehicle and motorcycle) and heavy vehicle were existed in 67 km/h and 61 km/h of car speed, respectively. The total traffic noise to the mean car speed decreased because of the inflow a lot of traffic volumes between 2016 and 2388 in the range of 67 km/h of light vehicle speed, in traffic composition of 4.75% heavy vehicles, and 1.11% motorcycle. the final result for this study showed that statistical paired t-test for between existence and nonexistence of soundproof trees was significant(p<0.05) and the difference between daytime and night in the location of the nonexistence of plant communities with the independent sample T-test was significant(p<0.05). However, the independent sample T-test for analyzing the variance of traffic noise between daytime and night was not significant(p>0.05).

• Journal of Korean Society of Environmental Engineers
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• v.31 no.4
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• pp.263-271
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• 2009

This study evaluated the flocs forming characteristics in the mixing zone to increase the coagulation effect in the drinking water plant. As a measuring tool of formed flocs, on-line particle dispersion analyzer (iPDA) was used in Y drinking water plant. To evaluate the forming flocs, many parameters such as poly amine, coagulant dosing amount, raw water turbidity, and pH was applied in this study. During the periods of field test, poly aluminium chloride (PACl) as a coagulant was used. With the increase of the raw water turbidities, poly amine was also added as one of aids for increasing in coagulation efficiency. The turbidity and pH of raw water was ranged from 7 to 9 and from 25 to 140 NTU, respectively. The increasing of raw water turbidity brought the bigger floc sizes accordingly. From a regression analysis, $R^2$ value was 0.8040 as a function of T, raw water turbidity. Floc size index (FSI) was obtained from a correlation equation as follows; FSI = 0.9388logT - 0.3214 Also, polyamine gave the bigger flocs the moment it is added to the coagulated water in the rapid mixing zone. One of parameters influencing the floc sizes was the addition of powdered active carbon(PAC) in the mixing zone. In case of higher turbidity of raw water, $R^2$ value was 0.9050 in the parameters of [PACl] and [PAC]; FSI = $0.0407[T]^{0.324}[PACI]^{0.769}[PAC]^{0.178}$ On-line floc monitor was beneficial to evaluate the flocs sizes depending on the many parameters consisting raw water properties, bring the profitable basic data to control the mixing zone more effectively.

• Korean Journal of Soil Science and Fertilizer
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• v.39 no.3
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• pp.123-135
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• 2006

Spatial variability and distribution map of soil properties and the relationships between soil properties and crop yields are not well characterized in agroecosystems that have been land leveled to facilitate more cultivation of the new reclaimed sloping highland. Potato, onion, carrot, Chinese cabbage and radish were grown on the coarse sandy loam soil in 2004. Soil moisture content, soil penetration resistance and crop yield were sampled in the $10m{\times}50m$ field consisted of five plots. Sampling sites of each cultivation plot were 33 for the soil moisture, 11 for the soil penetration and 33 for the crop yield. The results of semivariance analysis, most of models were shown spherical equation. The significant ranges of each spatial variability model for the soil moisture, soil penetration and crop yield were broad as 33-35 meters in the potato cultivation plot, and that in the Chinese cabbage cultivation plot was narrow as 5-6 meters. The coefficient of variances (C.V.) of moisture, penetration and yield were various from 14 to 59 percents in five cultivation plots. The highest C.V. of potato yield was 59 percents, and that of the radish cultivation plot was as low as 14 percents. The required sample numbers for the determination of soil moisture content, soil penetration resistance and crop yield with error 10% at 0.05 significant level were ranged 8-40 for soil moisture, 7-25 for soil penetration and 424-4,678 for crop yield. The variogram and distribution map by kriging described field characteristics well so that the spatial variability would be useful for soil management for better efficiency and precision agriculture in the reclaimed highland.

• Journal of the Korean Institute of Landscape Architecture
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• v.45 no.3
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• pp.21-29
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• 2017

In this study of visitor place attachment to parks, Scannel and Gilford considered the dimensions of place attachment, and proposed the theoretical framework of PPP(Place, Person, Process) that should be systematically studied from the perspective of person, place and psychological processes. According to Scannel's theoretical basis, this paper puts forward the hypothesis of a structure model of place attachment. In the model, the five independent variables of people, places, cognition, emotion, and behavior have influenced the dependent variable of place attachment. The questionnaire was conducted on 18 neighborhood parks in Kunming, China, and the residents of the 5 neighborhood parks in Daejeon, South Korea. A total of 1,645 valid samples of the questionnaire survey were collected. Through confirmatory factor analysis(CFA) results of the inspection of the various elements, it was shown that the reliabilities of 6 latent variables, such as people, places, cognition, affection, behavior and place attachment, which were composed with the observed variables(30 observed variables in Daejeon, 19 observed variables in Kunming), were all above 0.7 and the data were fit for this study. The hypothesis test results found that the physical environment of the neighborhood parks such as a comfortable environment, pleasant road and convenient facilities would increase the rate of visitors coming back. From the park management perspective, to increase the amount of visitors to the park, the park should increase visibility, provide more organized, varied activities and meetings, or special exhibitions according to the particular characteristics of the individual park, to increase awareness of the park. From the park visitors' psychological perspective, visitors are seeking to enjoy the park facilities and environment not only to bring physical relaxation, but also to bring about a psychological cure. With the commonality of attachment structure between the two countries, to improve the place attachment of neighborhood park visitors, collecting regularly visitor feedback will facilitate the sustainable development of neighborhood park attachment.

• Korean Journal of Agricultural Science
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• v.10 no.2
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• pp.324-333
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• 1983

Modeling of longterm runoff is theoritically based on waterbalance analysis. Simplified equation of water balance with rainfall, evapotranspiration and soil moisture storage could be formulated into regression model with variables of rainfall, pan evaporation and previous-month streamflow. The hydrologic response of water shed could be represented lumpedly, qualitatively and deductively by regression coefficients of water-balance regression model. Characteristics of regression modeling of water-balance were summarized as follows; 1. Regression coefficient $b_1$ represents the rate of direct runoff component of precipitation. The bigger the drainage area, the less $b_1$ value. This means that there are more losses of interception, surface detension and transmission in the downstream watershed. 2. Regression coefficient $b_2$ represents the rate of baseflow due to changes of soil moisture storage. The bigger the drainage area and the milder the watershed slope, the bigger b, value. This means that there are more storage capacity of watershed in mild downstream watershed. 3. Regression coefficient $b_3$ represents the rate of watershed evaporation. This depends on the s oil type, soil coverage and soil moisture status. The bigger the drainage area, the bigger $b_3$ value. This means that there are more watershed evaporation loss since more storage of surface and subsurface water would be in down stream watershed. 4. It was possible to explain the seasonal variation of streamflow reasonably through regress ion coefficients. 5. Percentages of beta coefficients what is a relative measure of the importance of rainfall, evaporation and soil moisture storage to month streamflow are approximately 89%, 9% and 11% respectively.

• Journal of Environmental Impact Assessment
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• v.27 no.4
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• pp.353-366
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• 2018

The purpose of this study was assessment the quality of water by using the statistical analysis technique of the Water flow and water quality from January 2012 to December 2016 at the unit basin for total pollutant load management system (TPLMS) in the Imjin River. Water flow and water quality were monitored at an average of 8 day intervals, 11 parameters were used for correlation analysis, principal component analysis (PCA), factor analysis (FA), and cluster analysis (CA). The Hierarchical CA was classified into three according to the change of space, such as natural rivers, urban rivers, point with large influence of point pollution source, it was found that the type of contamination source the similarity of water quality affected the classification of cluster. Using one-way analysis of variance (ANOVA) and post-hoc Analysis, there were statistically significant differences between mean values among the clusters. Correlation analysis showed the correlation coefficient between $COD_{Mn}$ and TOC was 0.951 (p<0.01) and the correlation was statistically significantly higher. According to the result PCA and FA, 3 principal components can explaining 72% of the total variations in water quality characteristics and main factor was EC, $BOD_5$, $COD_{Mn}$, TN, TP and TOC indirect indicators of organic matter and nutrients were influenced. This study presented the regression equation obtained by applying the factor scores to the multiple linear regression analysis and concluded that the management Indirect indicators of organic matter and nutrients is important for water quality management in the Imjin River basin.

• Korean Journal of Soil Science and Fertilizer
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• v.37 no.4
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• pp.220-227
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• 2004

Phosphorus desorption study is essential to understanding P behavior in agricultural and environmental soils because phosphorus is considered as two different aspects, a plant nutrient versus an environmental contaminant. This study was conducted to determine soil P buffering power related to P desorption quantity intensity (Q/I) parameters, $Q_{max}$(an index of P release capacity) and $l_0$(an index of the intensity factor), and to investigate the characteristics of relationship between the P desorption Q/I parameters and the soil properties. Soil samples were prepared with treatments of 0 and $100mg\;P\;kg^{-1}$ applied as $KH_2PO_4$ solution. The P desorption Q/I curves were obtained by a procedure using anion exchange resin beads and described by an empirical equation ($Q=aI^{-1}+bln(I+1)+c$). The P desorption Q/I curves for the high available P (${\g}20mg\;kg^{-1}$ of Olsen P) soils were characteristic concave trends with or without soil P enrichment, whereas for the low available P (${\lt}20mg\;kg^{-1}$ of Olsen P) soils, the anticipated Q/I concave curves could not be obtained without a proper amount of P addition. When the soils were enriched in phosphates, the values of desorbed solid phase labile P and solution P, such as $Q_{max}$ and $I_0$ respectively, were increased, but the ratio of $Q_{max}$ versus $I_0$ was decreased. Thus, the slope of desorption Q/I curve represented as phosphorus buffering power, $|BP_0|$, is decreased. The $|BP_0|$ values of the high available P soils ranged between 48 and $61L\;kg^{-1}$ in the P untreated samples and between 18 and $44L\;kg^{-1}$ in the P enriched samples. Overall $|BP_0|$ values of both low and high available P soils treated with $l00mg\;P\;kg^{-1}$ ranged between 14 and $79L\;kg^{-1}$. The $Q_{max}$, values ranged between 71.4 and $173.1mg\;P\;kg^{-1}$, and the lo values ranged between 0.98 and $3.82mg\;P\;L^{-1}$ in the P enriched soils. The $Q_{max}$ and $I_0$ values that control the P buffering power may be not specifically related to a specific soil property, but those values were complicatedly related to soil pH, clay content, soil organic matter content, and lime. Also, phosphorus release activity, however, markedly depended on the desorbability of the applied P as well as the native labile P.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.113-120
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• 2005

An understanding of soil-structure interaction is the key to rational and economical design for laterally loaded drilled shafts. It is very difficult to formulate the ultimate lateral capacity into a general equation because of the inherent soil nonlincarity, nonhomogeneity, and complexity enhanced by the three dimensional and asymmetric nature of the problem though extensive research works on the behavior of deep foundations subjected to lateral loads have been conducted for several decades. This study reviews the four most well known methods (i.e., Reese, Broms, Hansen, and Davidson) among many design methods according to the specific site conditions, the drilled shaft geometric characteristics (D/B ratios), and the loading conditions. And the hyperbolic lateral capacities (H$_h$) interpreted by the hyperbolic transformation of the load-displacement curves obtained from model tests carried out as a part of this research have been compared with the ultimate lateral capacities (Hu) predicted by the four methods. The H$_u$ / H$_h$ ratios from Reese's and Hansen's methods are 0.966 and 1.015, respectively, which shows both the two methods yield results very close to the test results. Whereas the H$_u$ predicted by Davidson's method is larger than H$_h$ by about $30\%$, the C.0.V. of the predicted lateral capacities by Davidson is the smallest among the four. Broms' method, the simplest among the few methods, gives H$_u$ / H$_h$ : 0.896, which estimates the ultimate lateral capacity smaller than the others because some other resisting sources against lateral loading are neglected in this method. But it results in one of the most reliable methods with the smallest S.D. in predicting the ultimate lateral capacity. Conclusively, none of the four can be superior to the others in a sense of the accuracy of predicting the ultimate lateral capacity. Also, regardless of how sophisticated or complicated the calculating procedures are, the reliability in the lateral capacity predictions seems to be a different issue.