• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2336-2341
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• 2002

When WC and group IV elements are added to Ti(C,N)-Ni cermet, microstructures of the cermet is changed. The change effects directly on the property of the material. In this study, the amount of WC and group IV elements of Ti(C,N) cermet tool was investigated. The composition of WC was changed from 5 to 20wt% to determine the effect of WC on the cutting performance of cermet tool. The more WC was added, the longer the tool life of the cermet tool was. The cermet with lwt% ZrC and l4wt% WC showed the best cutting performance among the investigated cermet tools. The cutting performance of cermet cutting tools suggests the possibility in interrupted cutting for reliability test experimentation was performed repeatedly with $Ti(C_{0.7},N_{0.3})- l4WC-1ZrC-20Ni$ cermet tool machining SCM440. The flank wear of cermet cutting tool at given time condition is suitable for Normal distribution and Log normal distribution by Chi squared test.

• The Journal of Industrial Distribution & Business
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• v.9 no.9
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• pp.25-33
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• 2018

Purpose - In this study, we consider and examine relationships between reasons for business switch or liquidation (BSL), and the demographics of small and medium enterprises (SMEs) in South Korea. The related five variables are occupations, administrative districts, age of employer, firm age and foundation motivation. In addition, eleven levels in association with reasons for BSL visualize the corresponding demographics by measuring their similarity on the dimensional planes assuming that the association exists between variables under consideration. Research design, data, and methodology - This study is done by the Ministry of SMEs and Startups in 2016 and examines 20,307 small and medium enterprises. For examining the distinct relationships among variables under consideration, both chi-squared test and correspondence analysis as main statistical tools are used. Results - The results show that among levels of reasons for BSL the three levels -weakening profitability, poor sales and economic depression- are main ones for the five demographics variables mentioned above, and we can obtain the detailed associations between attributes of corresponding variables by inspecting the two dimensional plane. Conclusions - This study suggests reasons for BSL are closely associated with the five different demographics variables - Administrative districts, Firm age, Occupations, Age of employer and Foundation motivation-by looking over results.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.740-746
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• 2010

Rainwater has been used in many countries as a way of minimizing water availability problems. Rainwater harvesting system (RHS) has been successfully implemented as alternative water supply sources even in Korea. Although RHS is an effective alternative to water supply, its efficiency is often heavily influenced by temporal distribution of rainfall. Since natural precipitation is a random process and has probabilistic characteristics, it will be more appropriate to describe these probabilistic features of rainfall and its relationship with design storage capacity as well as supply deficit of RHS. This study presents the methodology to establish the relationships between storage capacities and deficit rates using probability distributions. In this study, the real three-story building was considered and nine scenaries were developed because the daily water usage pattern of the study one was not identified. GEV, Gumbel and the generalized logistic distribution ware selected according to the results of Kolmogorov-Smirnov test and Chi-Squared test. As a result, a set of curves describing the relationships under different exceedance probabilities were generated as references to RHS storage design. In case of the study building, the deficit rate becomes larger as return period increases and will not increase any more if the storage capacity becomes the appropriate quantity. The uncertainties between design storage and the deficit can be more understood through this study on the probabilistic relationships between storage capacities and deficit rates.

• Fashion & Textile Research Journal
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• v.21 no.6
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• pp.743-753
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• 2019

This study investigates differences in demographic characteristics, shopping orientation, perceived risk, and satisfaction after purchase among consumer types. This study classifies consumer types according to their channel transition behaviors between the online and offline channels with a focus on the steps of information research and buying decision in buying decision-making process. The four consumer groups are as follows: off-off type (offline research-offline purchase), on-on type (online research-online purchase), on-off type (online research-offline purchase) and on/off-off type (online and offline research-offline purchase), off-on type (offline research-online purchase) and on/off-on type (online and offline research-online purchase). Data were collected from adults over 20 years old who had bought clothes within one year. The questionnaire was carried out from July, 2019 using a professional internet research panel; in addition, 500 sets of useful data were analyzed by descriptive statistics, factor analysis, reliability analysis, chi-squared test, ANOVA and Duncan-test using SPSS 21.0. The findings showed significant differences among the classified consumer groups for consumer demographics, shopping orientation, perceived risk, and purchase after satisfaction. The results imply that consumers show a variety of channel transition behaviors based on demographic variables, shopping orientation, and perceived risk. Understanding and adapting to consumer purchase behaviors will allow company distribution channels to be effectively managed and eventually increase consumer satisfaction as well as company sales volume.

• Communications for Statistical Applications and Methods
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• v.19 no.1
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• pp.107-115
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• 2012

Yoo and Cook (2007) developed an optimal sufficient dimension reduction methodology for the conditional mean in multivariate regression and it is known that their method is asymptotically optimal and its test statistic has a chi-squared distribution asymptotically under the null hypothesis. To check the effect of dimension used in estimation on regression coefficients and the explanatory power of the conditional mean model in multivariate regression, we applied their method to several simulated data sets with various dimensions. A small simulation study showed that it is quite helpful to search for an appropriate dimension for a given data set if we use the asymptotic test for the dimension as well as results from the estimation with several dimensions simultaneously.

• The Mathematical Education
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• v.49 no.1
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• pp.85-109
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• 2010

The purpose of the study is to devise syllabus in which traditional textbooks were rearranged by van Hiele Level theory and van Hiele instruction step 5 was applied to syllabus which used computer software, GSP especially in step 2 for students who studied properties and relations of the figure. Another purpose is to analyze the van Hiele Level distribution and find out how significant improvement syllabus based instruction could make compared with the traditional classes using textbooks. The results of the study revealed that more than half of the students were less than Level 1 in the comparative group but more than half of the students have reached Level 3 in the experimental group. And improvement of van Hiele Level was significant in syllabus based classes compared with traditional classes using textbooks by the Welch-Aspin tests and Chi-squared tests.

• Journal of Sasang Constitutional Medicine
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• v.11 no.1
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• pp.159-168
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• 1999

Purpose : Sasang Constitutional Medicine explains the pathology peculiar to constitution and suggests treatment for each constitution. In Sasang Constitutional Medicine hwnan beings are classified on four groups; Taeyangin, Taeumin, 5oyangin, Soeumin. These four constitution has their's own symptoms and treatments. In treatment, control of mind inclination, that is to say, moderation takes a very important role. But the study on heredity in Sasang Constitutional Medicine has not done not biological study but also statistical study. So we used several statistical methods and analyzed 163 samples. Methods : We implemented Fishers exact test for adjusting chi-squared test, kappa coefficient to estimate agreement of parent's and children's constitutions, and finally plotted bi-plot using correspondence analysis. Results : From Fisher's exact test result, we could know that parent's and children'S constitution's distribution had significant difference. In kappa coefficient, mother and daughter's estimated value produced highest result. In correspondence analysis we only plotted the case of mother and son for easy interpretation. Conclusion : In the study of heredity of SaSang constitution, we cannot know exactly the heredity of constitution in terms of biology or genetics. But this research can be helpful for further analysis, that is, a study of biological or genetical aspects. And we could conclude that in statistical aspects the heredity in SaSang constitution is meaningful.

• Human Ecology Research
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• v.52 no.2
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• pp.165-173
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• 2014

The study was conducted to analyze whether the recent trends in preference toward small and medium-sized housing in Korea represent changes in space norms. To accomplish this, the existing data from Statistics Korea and two different empirical data sets collected in 2007 and 2012 from Ulsan, Korea, were statistically analyzed through descriptive statistics, cross-tabulation analysis with a chi-squared test and multiple regression analysis. In the analyses, the space norms of households were compared and any changes in the space norms and the related factors were determined. The space norms were mainly investigated in terms of the housing size and the number of rooms. The results are as follows: 1) since 2010, there have been changes in the housing stock distribution in terms of size. Stocks of small housing increased, while those of medium and large housing decreased. Nevertheless, the overall conditions of spatial density have improved considerably in the recent 30 years. 2) It was found that there were statistically significant differences between 2007 and 2012 in space norms. The norms for housing sized less than 99 m2 and with one or two rooms were found to have increased, while that for housing sized more than 132 m2 decreased. 3) Household size, education of the head, monthly household income, housing type and the number of bedrooms in the current dwelling were the significant explanatory variables of space norms.

• East Asian Journal of Business Economics (EAJBE)
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• v.10 no.3
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• pp.51-61
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• 2022

Purpose - The purpose of this study is to establish the government's logistics policy by calculating the logistics cost of the company and grasping the management status, to reduce the logistics cost of the related companies and to provide basic statistical data necessary for the management strategy. This work examines some associations between reasons for reducing corporate logistics costs (RCLC) and corporate classification such as industry and sales size. Research design, data, and methodology - The survey was conducted in 2018 for 2,000 companies based on the business of mining, manufacturing and wholesale and retail industries since 2010. The survey population is 94,976, of which 92,708 are small and medium enterprises and 2,268 are large corporations. The association among factors may be statistically and visually explored by using chi-squared test and correspondence analysis. Result - This study reveals the association between reasons for RCLC and corporate classification and properties and closeness that exist between the categories of each factor can be mined. Conclusion - As a task to reduce logistics costs of industrial products, expansion and operation of joint logistics business, establishment of cooperative logistics network, and establishment of ordinance on support for smart distribution logistics can be proposed.

• Child Health Nursing Research
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• v.29 no.4
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• pp.280-289
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• 2023

Purpose: This study investigated weight status in survivors of childhood acute lymphocytic leukemia (ALL) and identified related factors. Methods: A retrospective review of the electronic medical records of survivors of childhood ALL (n=230) was conducted. We analyzed the survivors' characteristics, including sex, age, weight status at diagnosis, central nervous system involvement, risk classification, length of treatment, radiation therapy, and hematopoietic stem cell transplantation. Analysis of variance and the chi-squared test were applied to investigate influencing factors. Results: The weight status distribution was as follows: 23 individuals (10.0%) were classified as underweight, 151 individuals (65.7%) were healthy weight, and 56 individuals (24.3%) were overweight/obese. Age at diagnosis (F=10.03, p<.001), weight status at diagnosis (x²=43.41, p<.001), and risk classification (F=10.98, p=0.027) showed significant differences among the weight status groups. Survivors who were older at diagnosis and those in the very high-risk category had a higher likelihood of experiencing underweight status during their survivorship, while survivors who were overweight/obese at diagnosis were more likely to remain overweight/obese at the time of survival. Conclusion: Considering the potential health implications related to an unhealthy weight status in survivors of ALL, it is imperative to undertake early identification and implement interventions for at-risk individuals.