• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.1
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• pp.93-100
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• 2012

In this paper, the deterministic optimal design for the tail plane made of composite materials is conducted under the deterministic loading condition and compared with that of the metallic materials. Next, the reliability analysis with five random variables such as loading and material properties of unidirectional prepreg is conducted to examine the probability of failure for the deterministic optimal design results. The MATLAB programing is used for reliability analysis combined with FEA S/W(COMSOL) for structural analysis. The laminated composite is assumed to the equivalent orthotropic material using classical laminated plate theory. The response surface methodology and importance sampling technique are adopted to reduce computational cost with satisfying the accuracy in reliability analysis. As a result, structural weight of composite materials is lighter than that of metals in deterministic optimal design. However, the probability of failure for the deterministic optimal design of the tail plane structures is too high to be neglected. The sensitivity of each variable is also estimated using probabilistic sensitivity analysis to figure out which variables are sensitive to failure. The computational cost is considerably reduced when response surface methodology and importance sampling technique are used. The study of the computationally inexpensive method for reliability-based design optimization will be necessary in further work.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.8
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• pp.1128-1140
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• 2002

As consumers' alternatives in fashion store selection increase, they select different store types to purchase different product types. Therefore, the probability of patronage mix behavior according to product type increases. Understanding consumers patronage mix behavior, finding out the determinant attributes of fashion stores for each product type are important to retailers and marketers for building a successful merchandising and marketing strategies. Most of the previous researches in store selection and patronage assume consumer behavior as single store patronage, and thus relatively little is known about patronage mix behavior. Also, little attention has been given to product characteristics as an important variable in store patronage behavior. The purposes of this study were to determine the effects of product characteristics in consumers patronage mix behavior. In this study, a theoretical model including product characteristics as an intervening variable between store attributes and patronage behavior was developed. A Questionnaire was developed and data were collected form 464 adult women living in Seoul area in Korea. Factor analysis, paired t-test, ANOVA, Duncan test and discriminant analysis were employed to analyze the data. As a result, the suggested model was partially verified. First, the product characteristic was found to have an effect on perceived importance of store attributes and on determinant attributes of stores. Consumers were found to use different evaluative criteria for store attributes when they purchase different product types. Second, the perceived importance of store attributes was determined by consumer characteristics as well as product characteristics. Third, the determinant attributes in store selection were affected not only by the perceived importance of store attributes but also by the type of product to be purchased.

• The Research Journal of the Costume Culture
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• v.22 no.3
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• pp.411-430
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• 2014

The purpose of this study is to identify the antecedents and consequence of role-relaxed consumption. Consumption-related variables were considered as antecedents, and fashion-related variable was considered as a consequence. Hedonic consumption, impulse buying, value consciousness, and brand sensitivity were included as consumption-related variables and fashion consciousness was included as a fashion-related variable. It was hypothesized that hedonic consumption, impulse buying, value consciousness, and brand sensitivity influence rolerelaxed consumption and then influence fashion consciousness. Data were gathered by surveying university students in Seoul, using convenience sampling. Two hundred twenty seven questionnaires were used in the statistical analysis, exploratory factor analysis using SPSS and confirmatory factor analysis and path analysis using AMOS. While hedonic consumption, impulse buying, value consciousness, and brand sensitivity were uni-dimensions, role-relaxed consumption and fashion consciousness were multi-dimensions. Factor analysis of role-relaxed consumption revealed two dimensions, 'self-centered decision making' factor and 'importance of intrinsic value' factor. In addition, factor analysis of fashion conscious revealed three dimensions, 'individualism' factor, 'dressing style' factor, and 'appearance' factor. Tests of the hypothesized path show that impulse buying and brand sensitivity negatively influence 'self-centered decision making' and that hedonic consumption and value consciousness negatively influence 'importance of intrinsic value'. While 'self-centered decision making'negatively influence 'dressing style' and 'appearance, 'importance of intrinsic value' negatively influences all factors of fashion consciousness. The implications of these findings and suggestions for future study are also discussed.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.88-96
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• 2010

We propose the efficient channel coding method combined with a 2.4kbps speech coder. The code rate of a channel coder is given by 1/2 and 1/2 rate convolutional coder is obtained from the punctured convolutional coder with rate of 1/3. The punctured convolutional coder is used for a variable rate allocation. The puncturing method according to the importance of the output data of the source encoder is applied for the convolutional coder. The importance of output data is analyzed by evaluating the bit error sensitivity of speech parameter bits. The performance of proposed coder is analyzed and simulated in Rayleigh fading channel and AWGN channel. The experimental results with 2.4kbps EHSX coder show that the variable rate channel coding method is superior to non-variable channel coding method from the subjective speech quality.

• Journal of Korea Game Society
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• v.21 no.4
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• pp.3-12
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• 2021

In this study, models for predicting the final result of League of Legends game were constructed for each rank using data from the first 10 minutes of the game. Variable importance was extracted from the prediction models to derive strategic direction in early phase of the game. As a result, it was possible to predict final results with over 70% accuracy in all ranks. It was found that early game advantage tends to lead to the final win and this tendency appeared stronger as it goes to challenger ranks. Kill(death) was found to be the most influential factor for win, however, there were also variables whose importance rank changed according to rank. This indicates there is a difference in the strategic direction in the early stage of the game depending on the rank.

• Fashion & Textile Research Journal
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• v.20 no.4
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• pp.389-399
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• 2018

The purpose of this study was to investigate the differences of sociocultural attitudes toward appearance, clothing and cosmetics purchasing behaviors according to male consumer's age group. The research method was survey and subjects were 656 male consumers. The results were as follows. First, three factors (appearance importance awareness, appearance internalization, and slimness importance awareness) were emerged on sociocultural attitudes toward appearance. Young age group showed higher level of appearance importance awareness and internalization than middle age group. Second, there were many differences on clothing purchasing behaviors by age variable. Young age group more importantly considered psycho-social purchasing motives, aesthetic selection criteria, and the internet as information source and purchasing place than middle age group. Whereas middle age group more importantly considered practical purchasing motives, practical selection criteria, and store display & salesman as information sources, and fashion outlet as purchasing place than young age group. Third, there were also many differences on cosmetics purchasing behaviors by age variable. Young age group used more and various cosmetics, and they more importantly considered skin improvement as purchasing motive, skin suitability and price as selection criteria, the internet as information source and purchasing place than middle age group. On the other hand, middle age group generally used fundamental cosmetics, and they more importantly considered skin protection as purchasing motive, quality as selection criterion, TV and store display & salesman as information sources, and discount store and cosmetics speciality store as purchasing places than young age group.

• Korean Journal of Ecology and Environment
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• v.43 no.1
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• pp.161-167
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• 2010

In this study, we implemented an experimental approach of ecological model development in order to emphasize the importance of input variable selection with respect to time-delayed arrangement between input and output variables. Time-series modeling requires relevant input variable selection for the prediction of a specific output variable (e.g. density of a species). Inadequate variable utility for input often causes increase of model construction time and low efficiency of developed model when applied to real world representation. Therefore, for future prediction, researchers have to decide number of time-delay (e.g. months, weeks or days; t-n) to predict a certain phenomenon at current time t. We prepared a total of 3,900 equation models produced by Time-Series Optimized Genetic Programming (TSOGP) algorithm, for the prediction of monthly averaged density of a potamic phytoplankton species Stephanodiscus hantzschii, considering future prediction from 0- (no future prediction) to 12-months ahead (interval by 1 month; 300 equations per each month-delay). From the investigation of model structure, input variable selectivity was obviously affected by the time-delay arrangement, and the model predictability was related with the type of input variables. From the results, we can conclude that, although Machine Learning (ML) algorithms which have popularly been used in Ecological Informatics (EI) provide high performance in future prediction of ecological entities, the efficiency of models would be lowered unless relevant input variables are selectively used.

• 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.

• Journal of Korean Society of Rural Planning
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• v.29 no.4
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• pp.105-116
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• 2023

In this study, evaluation indicators for quantitative and qualitative indicators were presented by resetting the evaluation indicators for the selection of the living conditions renovation project for vulnerable residential areas by reflecting the results of expert importance. The appropriateness of the project selection evaluation index was reviewed by comparing the results of the expert AHP importance survey to make the project sustainable and to discover vulnerable villages. Evaluation items were constructed based on the guidelines for selecting the target site, and AHP importance evaluation was performed using this evaluation item as a proxy variable. Based on the data collected from 152 villages in Gimhae-si for case studies, the evaluation results were derived by applying the existing guideline evaluation indicators and evaluation indicators reflecting the importance proposed in this study. As a result of the study, Overall, there was a positive correlation between the results of the existing guideline evaluation and the results of the AHP importance survey, but in detail, there is a difference in the results evaluated by the two evaluation methods. In the future, if the scope of participating experts is expanded to supplement the importance evaluation, and the evaluation grade is set by analyzing quantitative data from Gyeongsangnam-do or rural areas nationwide, local governments and others will use this evaluation index as basic data when promoting the project.

• School Mathematics
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• v.16 no.1
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• pp.19-37
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• 2014

This study investigated the degree of understanding pre-service teachers' random variable concept, based on the attention and the importance for developing pre-service teachers' ability on statistical reasoning in statistics education. To accomplish this, the subject of this study was 70 pre-service teachers belonged to three universities respectively. The teachers were given to 7 tasks on random variable and requested to solve them in 40 minutes. The tasks consisted of three contents in large; 1) one was on the definition of random variables, 2) the other was on the understanding of random variables in different/diverse conditions, and 3) another was on problem solving relevant to random variable concept. The findings are as follows. First, while 20% of pre-service teachers understood the definition of random variable correctly, most teachers could not distinguish between random variable and variable or probability. Second, there was a significant difference in understanding random variables in different/diverse conditions. Namely, the degree of understanding on the continuous random variable was superior to that of discrete random variable and also the degree of understanding on the equal distribution was superior to that of unequality distribution. Third, three types of problems relevant to random variable concept dealt with in this study were finding a sample space and an elementary event, and finding a probability value. In result, the teachers responded to the problem on finding a probability value most correctly and on the contrary to this, they had the mot difficulty in solving the problem on finding a sample space.