• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.32 no.4_1
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• pp.343-351
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• 2014

The correlation between regional Walkability Index and their physical socio-economic characteristics has evaluated by the spatial statistical analysis to understand the urban pedestrian environments, where has been emerging the significance, recently. Following to the study, the Walkability Indexes were calculated quantitatively from two administrative districts of Busan and measured Global Local spatial autocorrelation indices. Additionally, the Geographically Weighted Regression model was applied to define the correlation between Walkability Indexes and urban environmental variables. The spatial autocorrelation values and clusters on the Walkability Indexes were derived in statistically significant level. Furthermore, the Geographically Weighted Regression model has been derived more improved inference than the OLS regression model, so as the influence of local level pedestrian environment was identified. The results of this study suggest that the spatial statistical approach can be effective on quantitative assessing the pedestrian environment and navigating their associated factors.

• The Korean Journal of Applied Statistics
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• v.34 no.4
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• pp.589-597
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• 2021

In simple and multiple regression, there is a difference in the meaning of regression coefficients, and not only are the estimates of regression coefficients different, but they also have different signs. Understanding the relative contribution of explanatory variables in a regression model is an important part of regression analysis. In a standardized regression model, the regression coefficient can be interpreted as the change in the response variable with respect to the standard deviation when the explanatory variable increases by the standard deviation in a situation where the values of the explanatory variables other than the corresponding explanatory variable are fixed. However, the size of the standardized regression coefficient is not a proper measure of the relative importance of each explanatory variable. In this paper, the estimator of the regression coefficient in multiple regression is expressed as a function of the correlation coefficient and the coefficient of determination. Furthermore, it is considered in terms of the effect of an additional explanatory variable and additional increase in the coefficient of determination. We also explore the relationship between estimates of regression coefficients and correlation coefficients in various plots. These results are specifically applied when there are two explanatory variables.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4D
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• pp.443-450
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• 2009

Uninterrupted facility - since there is a close relationship between traffic volume, speed and density -, when a ramp traffic flow merges into the main line, will change the traffic speed or density, and the corresponding correlational model equation will be changed. Thus, this study, using time and space-series traffic data on areas under the influence of such a merging, identified sections which changed the correlation between speed and density variables, and examined such changes. As a result, the upstream and merging sections showed the "Underwood"-shaped exponent, and the downstream after passing the merging section showed a straight line "Greenshields" model. The downstream section which changed the correlation between speed and density showed a gradual downstream movement phenomenon within 100 m-500 m from the end of the third lane linking with the ramp, as the traffic approached the inner lanes. Also, the upstream section, merging section, and downstream section involving a change showed heterogeneous traffic flows which, in the speed-density model, have a statistically different free flow speed (constant) and a different ratio of free flow speed to jam density (gradient).

• English Language & Literature Teaching
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• v.18 no.1
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• pp.115-132
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• 2012

In order to confirm ecological validity of D$\ddot{o}$rnyei's second language motivational self, the present study investigated 495 South Korean secondary school students' L2 learning motivation and motivated behavior by using a questionnaire survey. The participants' ideal L2 self, ought-to L2 self, integrativeness, and instrumentality were examined and compared to identify which motivational factor had the most effect on their motivated L2 learning behavior. Among Korean secondary school students, the concept of integrativeness was replaced with the ideal L2 self as a more appropriate concept for understanding Korean secondary school students' L2 learning motivation. As for instrumentality, promotional aspects demonstrated a significant correlation with both the ideal and ought-to L2 selves, whereas preventional aspects showed a relatively high correlation with the ought-to L2 self. The ideal L2 self had the most impact on the motivated behavior, and the ideal L2 self and ought-to L2 self reflected the students' different motivational characteristics. It is suggested that D$\ddot{o}$rnyei's (2005, 2009) L2 motivational self system can be a better psychological model than Gardner's (1985) socio-educational model for understanding Korean secondary school students' L2 learning motivation.

• Journal of Integrative Natural Science
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• v.10 no.2
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• pp.78-84
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• 2017

CXC chemokine receptor 2 (CXCR2) is a prominent chemokine receptor on neutrophils. CXCR2 antagonist may reduce the neutrophil chemotaxis and alter the inflammatory response because the neutrophilic inflammation in the lung diseases is found to be largely regulated through CXCR2 receptor. Hence, in the present study, Hologram based Quantitative Structure Activity Relationship Study was performed on a series of CXCR2 antagonist named pyrimidine-5-carbonitrile-6-alkyl derivatives. The best HQSAR model was obtained using atoms, bonds, and chirality as fragment distinction parameter using hologram length 151 and 6 components with fragment size of minimum 4 and maximum 7. Significant cross-validated correlation coefficient ($q^2=0.774$) and non cross-validated correlation coefficients ($r^2=0.977$) were obtained. The model was then used to evaluate the six external test compounds and its $r^2_{pred}$ was found to be 0.614. Contribution map show that presence of cyclopropyl ring and its bulkier substituent's makes big contributions for improving the biological activities of the compounds. We hope that our HQSAR model and analysis will be helpful for future design of novel and structurally related CXCR2 antagonists.

• Journal of Integrative Natural Science
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• v.8 no.1
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• pp.40-47
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• 2015

Glycogen synthase kinase 3 (GSK-3) is a serine/threonine protein kinase that has recently emerged as a promising target in drug discovery. It is involved in multiple cellular processes and associated with the pathogenesis of several diseases. A three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis was performed on a series of GSK-3 inhibitors to understand the structural basis for inhibitory activity. Comparative molecular field analysis (CoMFA) method was used to derive 3D-QSAR models. A reliable CoMFA model was developed using ligand-based alignment scheme. The model produced statistically acceptable results with a cross-validated correlation coefficient ($q^2$) of 0.594 and a non-cross-validated correlation coefficient ($r^2$) of 0.943. Robustness of the model was checked by bootstrapping and progressive scrambling analysis. This study could assist in the design of novel compounds with enhanced GSK-3 inhibitory activity.

• Journal of Integrative Natural Science
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• v.8 no.1
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• pp.1-12
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• 2015

CRTh2 receptor is an important mediator of the inflammatory effects and act as beneficial target for the treatment of asthma, COPD, allergic rhinitis and atopic dermatitis. In the present work, Hologram QSAR studies were conducted on a series of 50 training set CRTh2 antagonists (2-(2-(benzylthio)-1H-benzo[d]imidazol-1-yl acetic acids). The best HQSAR model was obtained using atoms, bonds, connections and donor/acceptor as fragment distinction parameter using hologram length 257 and 6 components with fragment size of minimum 7 and maximum 10. Significant cross-validated correlation coefficient ($q^2=0.786$) and non cross-validated correlation coefficients ($r^2=0.954$) were obtained. The model was then used to evaluate the 15 external test compounds which are not included in the training set and the predicted values were in good agreement with the experimental results ($r^2_{pred}=0.739$). Contribution map show that presence of C ring and its substituents makes big contributions for activities. The HQSAR model and analysis from the contribution map could be useful for further design of novel structurally related CRTh2 antagonists.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.04a
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• pp.183-186
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• 2002

The objective of this study is to predict behavior of a contaminant plume and concentration of contaminants in soil through tile relations between the concentrations of contaminants in groundwater and in soil on the shallow sandy aquifer contaminated with petroleum hydrocarbons. The current state of the plume and its fate in the study area was simulated by using the MODFLOW-RT3D model and geochemical parameters of grounwater had been monitored and measured during 3 years (1999~2001). The relations between the concentrations of contaminants in each medium were taken from the investigation of site characterization conducted in 1999. Simulation results showed the center of the plume would migrate 407m twenty years later. At that time, the concentration would be decreased down to about 26 mg/$\ell$(93%). In comparison TEX concentration in the groundwater with that in the soil, the value of correlation coefficient (r=0.876) was as high as it could be used. Based on the high r-value, the linear equation was obtained from regression analysis. The results of model simulation by RT3D engine showed that the highest TEX concentration in the groundwater would be 58.8 mg/$\ell$ 16 years later, and then the TEX concentration in soil would be below the alarming level (80 mg/kg) of regulation criteria.

• Journal of Korean Society of Water and Wastewater
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• v.14 no.3
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• pp.281-290
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• 2000

This study investigates the prediction of daily water supply, which is a necessary for the efficient management of water distribution system. ANFIS, namely artificial intelligence, is a neural network into which fuzzy information is inputted and then processed. In this study, daily water supply was predicted through an application of network-based fuzzy inference system(ANFIS) for daily water supply prediction. This study was investigated methods for predicting water supply based on data about the amount of water which supplied in Kwangju city. For variables choice, four analyses of input data were conducted: correlation analysis, autocorrelation analysis, partial autocorrelation analysis, and cross-correlation analysis. Input variables were (a) the amount of water supply, (b) the mean temperature, and (c) the population of the area supplied with water. Variables were combined in an integrated model. Data of the amount of daily water supply only was modelled and its validity was verified in the case that the meteorological office of weather forecast is not always reliable. Proposed models include accidental cases such as a suspension of water supply. The maximum error rate between the estimation of the model and the actual measurement was 18.46% and the average error was lower than 2.36%. The model is expected to be a real-time estimation of the operational control of water works and water/drain pipes.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.6
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• pp.871-881
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• 2012

This study suggested a model that can predict a degradation condition over time of two plastic pipes, PE and PVC, which are currently used in the country. This study was analyzed physical characteristics change of plastic pipes by comparison with initial physical characteristics (on the case of new pipes). Since this is dependent on accidents that already occurred, there are limitations that it only decides a priority on improvement based on relative corrosion status rather than precautionary aspects. The comparison results between physical degradation by the deducted performance rating and a conventional numerical scoring method showed that correlation coefficient was 0.67 for PE pipes and 0.86 for PVC pipes, indicating a high correlation. According to this result, it has been decided that the performance rating suggested herein can be applied naturally to the criterion of an improvement decision, which was based on Scoring System. From results of the research, it is expected that a reliable result can be provided to an improvement decision process related to degradation of plastic pipes by comprehensively comparing and evaluating a condition of pipe materials(direct factors) and an environmental impact(indirect factors).