• Asian-Australasian Journal of Animal Sciences
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• v.22 no.7
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• pp.923-930
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• 2009

This study was conducted to compare three models: two random regression models with and without considering heterogeneity in the residual variances and a lactation model (LM) for evaluating the genetic ability of Holstein cows in Korea. Two datasets were prepared for this study. To apply the test-day random regression model, 94,390 test-day records were prepared from 15,263 cows. The second data set consisted of 14,704 lactation records covering milk production over 305 days. Raw milk yield and composition data were collected from 1998 to 2002 by the National Agricultural Cooperative Federation' dairy cattle improvement center by way of its milk testing program, which is nationally based. The pedigree information for this analysis was collected by the Korean Animal Improvement Association. The random regression models (RRMs) are single-trait animal models that consider each lactation record as an independent trait. Estimates of covariance were assumed to be different ones. In order to consider heterogeneity of residual variance in the analysis, test-days were classified into 29 classes. By considering heterogeneity of residual variance, variation for lactation performance in the early lactation classes was higher than during the middle classes and variance was lower in the late lactation classes than in the other two classes. This may be due to feeding management system and physiological properties of Holstein cows in Korea. Over classes e6 to e26 (covering 61 to 270 DIM), there was little change in residual variance, suggesting that a model with homogeneity of variance be used restricting the data to these days only. Estimates of heritability for milk yield ranged from 0.154 to 0.455, for which the estimates were variable depending on different lactation periods. Most of the heritabilities for milk yield using the RRM were higher than in the lactation model, and the estimate of genetic variance of milk yield was lower in the late lactation period than in the early or middle periods.

• Journal of Distribution Science
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• v.13 no.8
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• pp.91-96
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• 2015

Purpose - This study reviews the delivery of child welfare service quality and examines how the dimensions of the variables of customer satisfaction impact the results from a service distribution perspective. This study differs from existing research since it proposes that a recognized level of child welfare service quality is necessary to achieve customer satisfaction from the perspective of service distribution. Research design, data, and methodology - This study explores child welfare service quality factors that affect customer satisfaction. The study examines and analyzes demographic variables, service quality dimensions, and the causal relationships between child welfare service quality and customer satisfaction. Data from 300 child welfare cases were collected from organizations in Korea in the areas of Busan and Gyeongsangnamdo. The methods of analysis are as follow. First, using descriptive analysis frequency, the percentages were evaluated to assess the demographic variables. Second, Cronbach's α was used to test reliability and to evaluate the internal consistency of the measuring of items. Third, multiple regression analysis was conducted to find out how much the independent variable can affect customer satisfaction. Results - Five factors of child welfare service quality were identified in three categories: process quality (assurance, empathy), results quality (reliability, caring), and physical environment quality (tangibles). There were significant differences among the effects of the child welfare service quality factors on customer satisfaction. A multiple regression analysis was done with process quality (assurance, empathy), results quality (reliability, caring) and physical environment quality (tangibles) to test the hypothesis: assurance (t=2.434, p<0.05), empathy (t=3.677, p<0.001), reliability (t=3.271, p<0.05), caring (t=4.380, p<0.000), and tangibles (t=3.654, p<0.01) had a positive influence on child welfare service quality from a service distribution perspective. Therefore, hypotheses 1, 2, 3, 4, and 5 were supported. In addition, multiple regression analysis on the effects of the variables showed that caring (β=0.273), empathy (β=0.246), tangibles (β=0.265), reliability (β=0.152), and assurance (β=0.131) all had a positive and strong influence on child welfare service quality from a service distribution perspective. Therefore, all child welfare service quality categories (process, results and physical environment quality) were positively statistically significant. Conclusion - In this study, the main findings can be summarized as follows. First, the quality of service of child welfare consists of three dimensions of quality: process quality, results quality, and physical environment quality. The results of the multiple regression analysis also showed that caring and reliability were confirmed as more meaningful variables by the increasing loading factors. Second, the family members involved in child welfare proposed caring as the most important variable among the dimensions of service quality. Third, the results of the hypothesis testing using regression showed that all child welfare service quality factors had a positive impact on customer satisfaction. The results of the study could provide useful information to help increase the effectiveness of delivery strategies for child welfare service quality from a service distribution perspective.

• Journal of the Korean Graphic Arts Communication Society
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• v.30 no.1
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• pp.71-81
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• 2012

A research framework and hypothesis were established for analysing layout-factors of bus wrapping which influence on brand attitude. 130 questionnaire were distributed and 123 copies were retreated at metropolitan area. SPSS 12.0 was used for frequency analysis, factor analysis, and reliability analysis. For testing hypothesis multi-regression analysis were utilized. Attention, readability, explicitness, formativeness, creativity are partially significant to establish brand attitude. Attention and readability are insignificant, while explicitness, formativeness, creativity are significant to establish brand attitude. The most effective independent variables are creativity, and explicitness and formativeness are followed. In particular sensual, original, fresh layout of bus wrapping are highly significant.

• Journal of Korean Association for Spatial Structures
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• v.14 no.1
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• pp.61-68
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• 2014

The design of foot-bridge is often influenced by natural frequency. Consequently, vibration frequency becomes important. The empirical expressions used to quantify this parameter at the design phase have not been developed enough to give guideline to Korean foot-bridge. This paper is concerned with the vertical natural frequency of steel foot-bridges. It describes the vibration measurement methods employed for testing structures and presents reliable methods of assessing natural frequency from jumping vibration tests. Data from measurements on 16 structures in Seoul are given. Regression formulas of natural frequency for steel-framed foot-bridges are suggested. Finally, obtained formula are compared with empirical expressions of Seoul City's guideline.

• English Language & Literature Teaching
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• v.18 no.1
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• pp.171-195
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• 2012

While noticing that there is insufficient interest in the assessment of EFL learners' vocabulary levels or sizes, the researchers developed two tests identical in form (Forms A and B) to assess the lexical knowledge of Korean university learners at the $1^{st}{\sim}10^{th}$ 1,000 word bands by adapting a pre-established vocabulary levels test (VLT). Of equal concern was to investigate if the VLT was equally a valid and reliable instrument to be used on measuring the lexical knowledge of EFL learners. The participants were 804 university freshmen enrolled in a General Education English Course from four different colleges. The learners were asked to respond to either Form A or B. While scores generally fell towards the lower frequency bands, multiple regression found the Korean College Scholastic Ability Test (CSAT) to be a significant variable for predicting the learners' vocabulary sizes. From a methodological perspective, however, noticeable differences between Forms A and B could be found with item response theory analysis. The findings of the study provide suggestions on how future VLT for testing EFL learners may have to be redesigned.

• Geomechanics and Engineering
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• v.22 no.2
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• pp.165-171
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• 2020

Laboratory determination of strength and deformation behavior of clean sands and gravels has always been challenging due to the difficulty in obtaining their undisturbed samples. An alternative solution to this problem is to develop correlations between mechanical properties of cohesionless soils and their gradation characteristics. This study presents database of 3 natural sands with 11 varying particle size gradation curves to allow investigating relationships between mean particle size, maximum and minimum void ratio, relative density and shear strength of the test soils. Direct shear tests were performed at relative densities of 50, 75 and 95% to explore the effects of gradation and density on the angle of internal friction of the modeled sand samples. It is found that the mean grain size D₅₀ bears good correlations with void ratio range (e_max - e_min) and peak angle of internal friction 𝜙'_peak. The generated regression models are in good agreement with published literature and can be considered as reliable for natural sands in Pakistan. These empirical correlations can save considerable time and efforts involved in laboratory and field testing.

• Culinary science and hospitality research
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• v.23 no.6
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• pp.89-98
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• 2017

This research focused on recognizing and empirically testing a relationship between brand personality congruence and brand extension, which can lead to effective marketing strategies for the hotel industry. The objective of this research was to identify how customer's brand personality congruence affect brand extension and to then address what the most appropriate brand extension types for hotel brands are. This study offered a better approach to assess the broader impact of extension strategy for the marketer managers. The methodology for achieving these objectives were described in the following sections: developing measurements based on extensive reviews of literature and analyzing data utilized a exploratory factor analysis and a series of simple linear regression analyses. The result of this study showed customer's brand personality congruence had a great impact on the customer's positive attitude toward core brand. However, customer's attitude toward core brand had no impact on the updated attitude. The findings provided some theoretical and managerial implications for hotel operators.

• Journal of Korean Society for Quality Management
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• v.46 no.2
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• pp.339-350
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• 2018

Purpose: The purpose of this study is to propose useful suggestions by analyzing the impact of SNS quality and the pressure which comes from SNS usage objectives on SNS discontinuance intention. Methods: We developed a SNS user's discontinuance intention model in terms of SNS quality and pressure of SNS usage. Survey data of SNS users was analyzed using multi-regression analysis for testing hypotheses. Results: We found that information quality plays an important role in lowering the SNS discontinuance intention. In addition, it was founded that pressure of social networking and information processing are positively related with the SNS discontinuance intention. Conclusion: We expect that this research can provide theoretical and practical implications. As for theoretical, this study can suggest the insight on conceptualization of SNS fatigue in the further study. Regarding practical implication, service providers can make their service strategies based on understanding our analysis.

• Journal of Preventive Medicine and Public Health
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• v.15 no.1
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• pp.179-186
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• 1982

The methods controlling the confounding factors were discussed using the data of secondary infertility with induced abortion. Mantel-Haenszel method and logistic model were applied in the analysis to find out which factors were confounding and/or effect modification variables. In the logistic analysis, the main effect of induced abortion, spontaneous abortion, age and interaction effect between induced abortion and spontaneous abortion were chosen as independent variables being regressed into logistic functions. Spontaneons abortion was interpreted as a potential confounder and at the same time potential effect modifier and age was interpreted as potential confounder. Spontaneous abortion was shown to be more important influencing factor than age to the secondary infertility. In the course of logistic analysis, the problem of parameter estimation and hypothesis testing, assessing the fitness of a model, and selection of the best model were briefly explained. For the program of logistic model, FUNCAT Procedure of SAS package was chosen.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.115-119
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• 2006

The goal of this research is to develop and apply the generalized regression neural networks model (GRNNM) embedding genetic algorithm (GA) for pan evaporation, which is missed or ungaged and for the alfalfa reference evapotranspiration, which is not measured in South Korea. The GRNNM-GA is evaluated using the training, the testing, and reproduction performance respectively for the estimation of the PE and the alfalfa reference evapotranspiration. Since the observed data of the alfalfa reference evapotranspiration using lysimeter have not been measured for a long time in South Korea, the PM method is used to assume and estimate the observed alfalfa reference evapotranspiration. From this research, we evaluate the impact of the limited climatical variables on the accuracy of the GRNNM-GA. We should, furthermore, construct the credible data of the PE and the alfalfa reference evapotranspiration and suggest the reference data for irrigation and drainage networks system in South Korea.