• Journal of Korean Society for Quality Management
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• v.42 no.1
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• pp.43-61
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• 2014

Purpose: This study identifies preventive measures for VOC management by analyzing the causes and effects of factors that contribute to high risk service failure using FMEA on KORAIL VOC data. Methods: Two research methods were used. First, a Risk Priority Number (RPN) was assigned to each KORAIL VOC based on Failure Mode and Effect Analysis (FMEA). Second, multiple regression analysis was run with RPN factors that include severity, occurrence, and detection as the independent variables and customer dissatisfaction as the dependent variable. Results: Multiple regression analysis showed that RPN factors including severity, occurrence, and detection had significantly positive relationship with customer dissatisfaction. Based on these results, an FMEA was performed on VOC categories with high RPN for railroad stations including platform, ticketing, ticket verification, parking, and escalator, and VOC categories with high RPN for trains including entrance doors, cafes, air quality, announcement, and ticket verification. Conclusion: This study has practical implications to service failure management. A priority order using FMEA was established for the list of customer dissatisfactions that should be addressed to actively manage service failure, and strategies for tackling this priority list are offered.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.1140-1147
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• 2009

Productivity measurement of construction machinery is a significant issue faced by many contractors especially those involved in earthwork projects. Traditionally, equipment production rate has been estimated using data available in manufacturers' catalogues, results of previous construction projects, or personal experience and assessments of the site personnel. Actual production rates obtained after the completion of a project demonstrate the fact that most of these methods fail to provide accurate results and as a direct consequence, may lead to unrealistic project cost estimations prepared by the contractors. What makes this more critical is that in most cases, inadequate cost estimations lead the entire project to exceed the initial budget or fall behind the schedule. In this paper, a linear regression method to estimate bulldozer productivity is introduced. This method has been developed using SPSS-16 software package. The presented method is used to estimate the productivity of Komatsu D-155A1 series which is commonly used in many earthmoving operations in Iran. The data required for the numerical analysis has been collected from actual site observation and productivity measurement of 60 pieces of D-155A1 series currently being used in several earthmoving projects in Iran. Comparative analysis of the output data of the presented regression method and the existing productivity tables provided by the manufacturer shows that when compared to the actual productivity data collected on the jobsite, a significant increase in accuracy and a remarkable reduction of data variance can be achieved by using the presented regression method.

• Journal of Environmental Health Sciences
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• v.47 no.3
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• pp.279-291
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• 2021

Objectives: This study investigated the association between air pollutant levels and medical usage rates for environmental disease in a general residential area during the period 2015-2017. Methods: Air pollutant (PM₁₀, PM_2.5, SO₂, NO₂, CO, O₃) data were collected from Air-Korea. Medical usage data on environmental disease (asthma, allergic rhinitis, atopic dermatitis) for the period 2015-2017 in a general residential area in Gyeongsangnam-do Province were provided by the National Health Insurance Corporation. Pearson correlation analysis and multiple regression analysis were conducted to investigate the association between air pollutant levels and medical usage rates (SAS 9.4). In the multiple regression analysis, environmental disease was set as the dependent variable and air pollutants were set as independent variables and analyzed using the General Linear Model. Results: Except for PM_2.5, the average concentration of air pollutants in the surveyed area was below than the air environment standards of Korea. NO₂ was higher than Korea's national average, but CO was similar. The others were lower than the Korea's national average. The daily medical usage rates for environmental disease were 1.38‰ for asthma, 9.90‰ for allergic rhinitis, and 0.32‰ for atopic dermatitis. As a result of correlation analysis, PM₁₀ and SO₂, NO₂ and CO were significantly correlated with asthma, PM₁₀ and NO₂ and CO were correlated with allergic rhinitis, and PM₁₀ and PM_2.5, SO₂, NO₂ and CO were correlated with atopic dermatitis. As a result of multiple regression analysis, PM₁₀ and SO₂ were found to have a higher effect on asthma, PM₁₀ and NO₂ on allergic rhinitis, and SO₂ and NO₂ on atopic dermatitis, compared to other air pollutants. Conclusion: According to these results, air pollutants such as PM₁₀ and SO₂ and NO₂ were associated with the medical usage rates of environmental disease even in relatively low concentrations. Therefore, continuous monitoring will be required for general residential areas.

• Genomics & Informatics
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• v.14 no.4
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• pp.187-195
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• 2016

In genetic association studies with high-dimensional genomic data, multiple group testing procedures are often required in order to identify disease/trait-related genes or genetic regions, where multiple genetic sites or variants are located within the same gene or genetic region. However, statistical testing procedures based on an individual test suffer from multiple testing issues such as the control of family-wise error rate and dependent tests. Moreover, detecting only a few of genes associated with a phenotype outcome among tens of thousands of genes is of main interest in genetic association studies. In this reason regularization procedures, where a phenotype outcome regresses on all genomic markers and then regression coefficients are estimated based on a penalized likelihood, have been considered as a good alternative approach to analysis of high-dimensional genomic data. But, selection performance of regularization procedures has been rarely compared with that of statistical group testing procedures. In this article, we performed extensive simulation studies where commonly used group testing procedures such as principal component analysis, Hotelling's $T^2$ test, and permutation test are compared with group lasso (least absolute selection and shrinkage operator) in terms of true positive selection. Also, we applied all methods considered in simulation studies to identify genes associated with ovarian cancer from over 20,000 genetic sites generated from Illumina Infinium HumanMethylation27K Beadchip. We found a big discrepancy of selected genes between multiple group testing procedures and group lasso.

• Industry Promotion Research
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• v.9 no.4
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• pp.341-349
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• 2024

This study was conducted to determine the influence of housing condition variables on housing satisfaction. To this, the 2022 Housing Status Survey data was analyzed, and the total number of households targeted was 51,325. The data was analyzed using the SPSS PC+ Win. Ver. 24 program, and frequency analysis, correlation analysis, and multiple regression analysis were performed. The results of the study are as follows. First, the correlation analysis results showed that all housing condition-related variables were positively correlated. Among them, crack condition and waterproofing condition were strongly correlated. Second, the multiple regression analysis results showed that the structural soundness and crack condition of the house were the most important factors in housing satisfaction when the house was above ground. Third, when the house was semi-basement or underground, it was found that there was no influence other than the heating and noise conditions, except for the solidity and crack condition of the house. Based on these research results, suggestions for future research were made and policy measures were also revealed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.629-633
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• 2005

The reduction of the Vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to $R^2$ value and F-value. And testing for regression model is necessary to Independence, Homoscedesticity and Normality. Also we selected optimum layout of damping material using Taguchi method. As a result of application, sound quality is improved by more quiet, powerful, expensive, smooth.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.30 no.6 s.249
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• pp.728-733
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• 2006

The reduction of the Vehicle interior noise has been the main interest of NVH engineers. The driver's perception on the vehicle noise is affected largely by psychoacoustic characteristic of the noise as well as the SPL. In particular, the HVAC sound among the vehicle interior noise has been reflected sensitively in the side of psychology. In previous study, we have developed to verify identification of source for the vehicle HVAC system through multiple-dimensional spectral analysis. Also we carried out objective assessments on the vehicle HVAC noises and subjective assessments have been already performed with 30 subjects. In this study, the linear regression models were obtained for the subjective evaluation and the sound quality metrics. The regression procedure also allows you to produce diagnostic statistics to evaluate the regression estimates including appropriation and accuracy. Appropriation of regression model is necessary to $R^2$ value and F-value. And testing for regression model is necessary to independence, homoscedesticity and normality. Also we selected optimum layout of damping material using Taguchi method. As a result of application, sound quality is improved more quietly, powerfully, even though costly, and smoothly.

• The Korean Fashion and Textile Research Journal
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• v.10 no.1
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• pp.83-91
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• 2008

This study was designed to figure out the changes in elderly women's foot size and shape by aging, to propose size specification for elderly women's shoes, and to produce regression equations using representative measurements items to estimate other measurements usually hard to get. Subjects were 118 women of 30-59 years and the 227 elderly women over 60 years. Martin's anthropometry was done on the right foot of each subject for 25 items. And 11 indirect measurement items were measured on both foot printing sole outline and picture in profile taken by digital camera. For statistical analysis on the anthropometric measurements by SPSS program, analysis of variance, post-hoc test(SNK-test), crosstabulation, multiple correlation analysis, regression analysis were performed. The results of the study are as follows. Firstly, it was found that the foot figures of elderly women over 60 years were smaller in girth and width than those of below 60 years. In addition, it was revealed that a big toe and a little toe of elderly women showed a tendency concentrating to the central axis of feet. The foot index of elderly was smaller in width and girth. Secondly, foot size distribution table of elderly group showed wider size ranges and covered smaller sizes than the below the age of 60, meaning wide variation in foot size of elderly women. Thirdly, the multiple correlation analysis showed high correlation of foot length/girth to other measurements, suggesting these two items could be used as representative items for elderly women's shoe size specification as other age groups. Regression equations were produced using foot length/girth to estimate other measurements, suggesting such items could be estimated effectively and utilized in on/off-line shoe manufacturing shop as heel to big toe length, heel to little toe length, exterior malleouls width, instep girth, ankle girth, etc. These results imply prudent features of elderly women's foot as diversity of foot shape and wide size specification range should be applied for ergonomic shoe design for them.

• Research in Community and Public Health Nursing
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• v.32 no.4
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• pp.457-466
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• 2021

Purpose: The purpose of this study was to examine the correlations among emotional perception clarity, emotion regulation, family relationship, non-suicidal self-injury, and depression, and to determine associated factors of non-suicidal self-injury and depression for senior elementary school students. Methods: Data were collected from 150 early adolescences in K region, Korea. A self-report questionnaire consisted of Trait Meta-Mood Scale, Cognitive Emotion Regulation Questionnaire, Family Relationship Assessment Scale, Functional Assessment of Self-Mutilation, and Children's Depression Inventory. The data were analyzed using t-test, Pearson's correlation coefficient, logistic regression, and multiple regression analysis. Results: Non-suicidal self-injury and depression were positively associated with maladaptive emotion regulation strategy and family conflict, but negatively related to emotional perception clarity and family support. Adaptive emotion regulation strategy and family togetherness were only significantly correlated with depression. In logistic regression analysis, significant predictors of non-suicidal self-injury were emotional perception clarity, maladaptive emotion regulation strategy, and family support. Multiple regression analysis found that significant factors of depression were adaptive and maladaptive emotion regulation strategies, which explained 38.0% of the variance. Conclusion: Our study findings suggest that targeted intervention to reinforce the adaptive emotion regulation strategy and family relationship may prevent non-suicidal self-injury, and depression for senior elementary school students.

• Culinary science and hospitality research
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• v.15 no.3
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• pp.307-323
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• 2009

This study aims to redefine people's attitudes about well-being trend LOHAS(Lifestyles Of Health And Sustainability) by a systematic research on diners' perspectives about LOHAS and menu-selecting behavior since well-being trend has been a main interest of the media and the food service industry. Also, this study has focused on understanding customers' menu-selecting behavior through a customer interest survey and on customers' interests and verifying factors for healthy food inclination and satisfaction level to give basic information and marketing suggestions for healthful menu. SPSS 12.0 was used for the data analysis, and $x^$-test was carried to make clear the different perspectives about well-being trend LOHAS according to the general characteristics of those polled. Factor analysis was done to menu-selecting behavior. Differences between sampling menu-selecting factors and general characteristics(t-test & ANOVA) were inspected and multiple regression analysis between health inclination and satisfaction level was also conducted. According to the survey, customers' well-being menu selecting behavior showed highly in married women, relatively older people, those with higher general income and higher education. Regression analysis showed that menu-selecting behavior influenced customers' inclination toward health and satisfaction level. Therefore, the food service industry should target those groups and improve its promotional communication strategy with proper menu development and an improved concept.