• International Journal of High-Rise Buildings
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• v.11 no.4
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• pp.315-320
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• 2022

With the rapid development of urbanization the problems of pedestrian-level wind comfort and natural ventilation of tall buildings are becoming increasingly prominent. The velocity at the pedestrian level ($\overline{MVR}$) and variation of wind pressure coefficients $\overline{{\Delta}C_p}$ between windward and leeward surfaces of tall buildings were investigated systematically through numerical simulations. The examined parameters included building density ρ, height ratio of building α_H, width ratio of building α_B, and wind direction θ. The linear and quadratic regression analyses of $\overline{MVR}$ and $\overline{{\Delta}C_p}$ were conducted. The quadratic regression had better performance in predicting $\overline{MVR}$ and $\overline{{\Delta}C_p}$ than the linear regression. $\overline{MVR}$ and $\overline{{\Delta}C_p}$ were optimized by the NSGA-II algorithm. The LINMAP and TOPSIS decision-making methods demonstrated better capability than the Shannon's entropy approach. The final optimal design parameters of buildings were ρ = 20%, α_H = 4.5, and α_B = 1, and the wind direction was θ = 10°. The proposed method could be used for the optimization of pedestrian-level wind comfort and natural ventilation in a residential area.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.36 no.6
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• pp.611-620
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• 2018

With the revitalization of alley market area becoming a major goal of the urban regeneration project, an understanding on customer characteristics that affect the sales of alley market areas is needed. As spatial heterogeneity appears to exist in alley market areas, the use of GWR (Geographically Weighted Regression) is required as an alternative to OLS (Ordinary Least Squares) regression. This study analyzes effects of customer characteristics on sales of 1007 alley market areas in Seoul. Comparing R squared and AICc, results show that GWR is better than OLS regression. According to OLS regression, the ratio of female, the ratio of 40's and 50's, the number of employees, the opening rate of establishment, the density of building and the size of alley market area have positive effects on sales, while the ratio of 20's and 30's, the distance of bus stop and that of subway station have negative effects. As a result of comparing local regression coefficients of geographically weighted regression analysis, the ratio of female customers has the greatest effect on the northwestern region, followed by the southwestern region, the central region and the northeastern region. The ratio of 20's and 30's and that of 40's and 50's effect on the southeastern and northeastern regions, and then the southwestern region. It is expected that this study will help to identify marketing target for each alley market area.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.1
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• pp.46-56
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• 2018

This paper aimed to identify main factors of community characters, which have an effect on the land surface temperature(LST) change and estimate the impacting coefficient(ratio) of factors in a significant level of statistics. Chungcheongbuk-do province was selected and then partitioned into city and county areas for the sake of convenience of modeling. LST time series data and the community character data were developed based on Terra Satellite MODIS data and collected from the National Statistical Office, respectively. By the cause and effect relationship between community characters and LST, regression coefficients were estimated using a penal model. In a panel modeling, LST and community characters were used as a dependent variable and explanatory variables, respectively. Panel modeling analysis was carried out using statistical package STATA14 and one-way fixed effect model was selected as the most suitable model to evaluate the regression coefficients in the study area. The impacting ratio of LST change by any explanatory variable derived from the regression coefficients of the panel model fixed. Impacting ratios for industrial areas, elevation ${\times}$ building, energy usage, average window speed, non-urban management area, agricultural, nature and environmental conservation, average precipitation were 3.746, 2.856, 2.742, 0.553, 0.102, 0.071 and 0.003, respectively.

• Journal of Korea Water Resources Association
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• v.55 no.3
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• pp.229-243
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• 2022

The effects of monthly meteorological data measured at 11 stations in South Korea on pan coefficient were analyzed to develop the four types of multiple linear regression models for estimating pan coefficients. To evaluate the applicability of developed models, the models were compared with six previous models. Pan coefficients were most affected by air temperature for January, February, March, July, November and December, and by solar radiation for other months. On the whole, for 12 months of the year, the effects of wind speed and relative humidity on pan coefficient were less significant, compared with those of air temperature and solar radiation. For all meteorological stations and months, the model developed by applying 5 independent variables (wind speed, relative humidity, air temperature, ratio of sunshine duration and daylight duration, and solar radiation) for each station was the most effective for evaporation estimation. The model validation results indicate that the multiple linear regression models can be applied to some particular stations and months.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.715-720
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• 2003

The chief factors for the penetration and diffusion of chloride ions in concrete are water-cement ratio(W/C), aging, curing conditions, chloride ions concentration of given environment., wet and dry conditions and etc. In this study, of these factors effect of curing conditions such as standard and outdoor curing on the characteristics of chloride ions diffusion in concrete were researched when environmental factors for the penetration and diffusion of chloride ions were constant. For this purpose, the voltages passing through the diffusion cell were measured by using accelerated test method using potential difference, and then diffusion coefficients of chloride ions by using Andrade's method were estimated for 44%, 49.5% and 60% of w/c, respectively. As a result., according to curing conditions correlation among diffusion coefficients of chloride ions, W/C and aging were concluded through multiple regression model.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.16 no.1
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• pp.72-80
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• 2016

Re-auction happens when a bid winner defaults on the payment without making second in-line purchase declaration even after determining sales permission. This is a process of selling under the court's authority. Re-auctioning contract price of real estate is largely influenced by the real estate business, real estate value, and the number of bidders. This paper is designed to establish a statistical model that deals with the number of bidders participating especially in apartment re-auctioning. For these, diverse factors are taken into consideration, including ratio of minimum sales value from the point of selling to re-auctioning, number of bidders at the time of selling, investment value of the real estate, and so forth. As an attempt to consider ambiguous and vague factors, this paper presents a comparatively vague concept of real estate and bidders as trapezoid fuzzy number. Two different methods based on the least squares estimation are applied to fuzzy regression model in this paper. The first method is the estimating method applying substitution after obtaining the estimators of regression coefficients, and the other method is to estimate directly from the estimating procedure without substitution. These methods are provided in application for re-auction data, and appropriate performance measure is also provided to compare the accuracies.

• Journal of the Korean Home Economics Association
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• v.35 no.1
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• pp.415-428
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• 1997

In the present study we examined clothing expenditure patterns and related variables in Korea. In addition we analyzed the differences of clothing expenditure patterns between overall overspenders and non-overspenders. We use the Family Income and Expenditure Study published by the National Statistical Office of Korea. Double logarithm functional forms were used to adjust the normality of sample distribution and multiple regression analyses and t-test were utilized as a statistical tools. The present study was divided into four folders. First the income elasticity of clothing expenditures was examined by different groups such as age job and education levels of households as percentage change of clothing expenditures to a percentage change of income. Second to analyze the effects of demogtraphic and socio-economic variables on clothing expenditure we utlized the standardized coefficients in the separate regression equation by demographic and socio-economic variables. Third using spending to income ratio we investigated the differnces of the clothing expenditure patterns between overall overspenders and non-overspenders. Fourth the effects of independent variables by ovespenders and non-overspenders werediscussed.

• Journal of Korean Society for Atmospheric Environment
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• v.14 no.1
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• pp.1-10
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• 1998

Relationships between TSP and PM10 concentrations were evaluated using their respective data sets collected from Taegu and Kyeungsan areas during the period of December 1993 to November 1994. The collection of data was made using the gravimetric and $\beta$-ray absorption ($\beta$-MPM) methods for 7 days of every month from three urban sites in Taegu and one suburban site in Kyeungsan. Correlation coefficients between TSP and PM10 concentrations for these four sampling sites were found in the range of 0.85 $\sim$ 0.96. Correlation analysis was also conducted for $\beta$-PM concentration data that were measured only from the residential and commercial sites. The correlation coefficients between TSP and $\beta$-PM concentrations were 0.9 in the residential site and 0.8 in the commercial site. By contrast, the correlation coefficients between PM10 $\beta$-PM concentrations were almost identical for both the residential and commercial sites with a value of 0.88. The mean ratio for PM10 to TSP concentrations for all sites was appeared to be 0.68. The analysis of seasonal trends in PM10/TSP ratios showed that the contribution of PM10 to TSP concentrations was more significant during winter (0.70 $\sim$ 0.75) than during summer (0.61 $\sim$ 0.68). The results of this study may provide empirical informations on the compatability of aerosol data measured by different sampling methods.

• Journal of Biosystems Engineering
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• v.15 no.1
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• pp.23-32
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• 1990

Geometrical characteristics of fruit including perimeter, projected area and length of minor and major axis were calculated by computer programs to be used in fruit sorting by image processing system. The results are summerized as follows. 1. A program calculating perimeter, projected area, and length of minor and major axis by edge detection and chain code was developed. 2. Geometrical characteristics of given figures were calculated to verify the program and the discrepancies from the measured values were about 5%. 3. Regression models for estimating volums of apples were developed and regression coefficients for each variety were found. 4. Abnormal apples could be recognized by comparing the ratio of minor axis to major axis and the standard value was proposed.

• Journal of Korean Society on Water Environment
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• v.23 no.5
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• pp.731-739
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• 2007

In this study, water quality monitoring focused on TOC was performed at 5 points in Mihocheon (Stream) from January to December 2006. And 10 parameters (water temperature, pH, DO, EC, turbidity, SS, BOD, $PO_4-P$, TOC, TN) were monitored every month for one year. According to this study, TOC increased towards the lower stream (#4~#5). Correlation coefficients between TOC and DO, EC, turbidity, SS, BOD, $PO_4-P$, TN were -0.126, 0.351, 0.320, 0.286, 0.711, 0.525, 0.666. TOC was highly related to BOD. As a result of linear regression analysis, regression equation between BOD and TOC was BOD=0.58TOC+1.90 ($R^2=0.506$). In Mihocheon (Stream), BOD/TOC ratio decreased towards the lower stream. This results show decrease of ratio of biodegradable organic material to total organic pollutants towards the lower stream. This study is significant since it has revealed the potential value of TOC as organic material indicator for inquiry of water quality characteristics in the natural water system.