• 한국생산제조학회지
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• 제23권6호
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• pp.569-575
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• 2014

In this study, the effect of cutting edge geometry, such as helix and rake angles, on surface roughness in ball-end milling is investigated by using the Taguchi method. A set of experiments adopting the $L_{27}(3^{13})$ design with an orthogonal array are conducted with special WC ball-end mills having different helix and rake angles. Analysis of variance (ANOVA) is performed to analyze the effects of tool geometry and machining parameters, such as cutting speed, feed per tooth, and depth of cut, on surface roughness. The ANOVA results reveal that helix and rake angles are critical factors affecting surface roughness; the interaction of helix angle and cutting speed is also important. This research can contribute to novel cutting edge designs of ball-end mills and optimization of cutting parameters.

• International Journal of Aeronautical and Space Sciences
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• 제7권1호
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• pp.1-12
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• 2006

In this study, a surrogate model is applied to multi-objective aerodynamic optimization design. For the balanced exploration and exploitation, each objective function is converted into the Expected Improvement (EI) and this value is used as fitness value in the multi-objective optimization instead of the objective function itself. Among the non-dominated solutions about EIs, additional sample points for the update of the Kriging model are selected. The present method was applied to a transonic airfoil design. Design results showed the validity of the present method. In order to obtain the information about design space, two data mining techniques are applied to design results: Analysis of Variance (ANOVA) and the Self-Organizing Map (SOM).

• 대한안전경영과학회지
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• 제12권3호
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• pp.101-106
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• 2010

The purposes of this paper are to investigate an effect of weight of material and gender on postural stability and to introduce formulas for those. There were five levels of weights 0, 9, 18, 27 and 36 kg, and two levels of genders were conducted. Eight male and five female subjects participated in this experiment, ten tests were performed for each level of weights to measure the postural stability by using the stability platform. The effect of the genders and the load on the postural stability were statistically analysed by the two way ANOVA test and the regression analysis. The ANOVA test showed that the effect of weights was statistically significant on postural stability to the both male and female subjects. And the postural stability of female subjects was better than that of male subjects. A linear regression formula for the balancing time and the load and a formula for the reduction rate postural stability and the relative load were introduced by the regression analysis.

• 아동학회지
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• 제21권3호
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• pp.25-40
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• 2000

This study investigated the development of infant behaviors and maternal scaffolding in mother-infant games. Subjects were 60 mothers and their 9-, 12-, 15- and 18-month infants, 15 dyads in each age group. Mother-infant interaction was videotaped in the laboratory as they played peek-a-boo and a ball game in 2 sessions. Infant game behaviors were classified by the Rome-Flanders, Cossette, Ricard and $D{\acute{e}}carie$(1995) list, and maternal game behaviors were classified by the Hodapp, Goldfield & Boyatzis(1984) list. Data were analyzed by one-way ANOVA, two-way ANOVA with repeated measures, sequential analysis and Z test as well as qualitative analysis. Results showed that infants played an increasingly active role with age. Infants mastered the ball game at earlier age than peek-a-boo. Mothers scaffolded infant behaviors in various ways. The amount of maternal game behavior varied by type of game.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2022년도 봄 학술논문 발표대회
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• pp.37-38
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• 2022

This study is attempted to propose an appropriate number of measurements by checking and statistically analyzing the change in hardness according to the number of measurements. As a result, there was no significant difference between the 20th and 30th data, and in the 10th case, the effect on errors occurring during measurement was found to be dominant. Therefore, as the number of measurements, proposing 20 times in consideration of the convenience of use. In addition, in order to minimize the effect on the measurement error, it is proposed to remeasure the surface mane of the measurement surface and the test value in which the error occurs on the average of the test values.

• Restorative Dentistry and Endodontics
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• 제39권2호
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• pp.143-147
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• 2014

• Restorative Dentistry and Endodontics
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• 제39권1호
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• pp.74-77
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• 2014

• 한국의류학회지
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• 제22권1호
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• pp.159-169
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• 1998

The purpose of this study was to develop a large representative data base of market information for jeans apparel. This study was to observe consumer buying behavior and to determine the market share of various brands depending on several variables such as age and distribution regions. This study also analyzed the major factors in purchasing jeans for 17-29 age groups. The 660 questionnaires were distributed and 618 reliable ones were used for statistical analysis. A SAS statistical package including frequency' table, Chi-square test, factor analysis, analysis of variance(ANOVA), Duncan's multiple range test was used. The results of this study showed that consumer possessed about 6 pairs of jeans and bought about 3 pairs of jeans per year. The most recently purchased brand was Nix. Lots of brands were statistically significant at the segmented three age groups and in the five different distribution regions. The most popular type of design was the basic style. The result of factor analysis indicated 4 factors(quality/comfort, famous brand/fashion, mood/extrinsic attitude, economy). The result of ANOVA represented that three factors among them have influenced on the preferred design types.

• 응용통계연구
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• 제24권2호
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• pp.373-381
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• 2011

본 논문은 실험자료에 대한 분석모형으로 이원 분산분석모형을 가정한다. 고정효과 모형의 가정하에 요인별 변동량을 구하기 위한 방법으로 제1종 분석을 다루고 있다. 모형의 순차적 적합에 따라 얻어지는 요인별 제곱합의 계산방법으로 대수적 방법이 아닌 사영에 의한 분석방법을 제공한다. 관측자료를 다차원상의 공간벡터로 간주할 때, 최소 제곱법에 의한 요인별 변동량은 계획행렬로 생성되는 모수추정 공간에서 요인별 부분공간으로의 사영에 이르는 거리 제곱으로 구해질 수 있음을 논의하고 있다. 또한 사영행렬로 부터의 고유벡터와 고유근을 이용하여 요인별 변동량을 구하는 방법을 제공하고 있다. 균형자료나 불균형자료에서 모형의 순차적 적합에 따른 제1종 분석이 행해질 때 요인별 변동량의 합은 처리제곱합과 일치하나 제2종 분석의 경우 불균형자료에서 이러한 성질이 만족되지 않음을 논의하고 있다.

• 한국의류학회지
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• 제33권10호
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• pp.1673-1682
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• 2009

The purpose of the study was to investigate differences in: 1) importance of buying motives including external stimuli and sales promotional stimuli among groups according to levels of diversity orientation; 2) importance of buying motives including external stimuli and sales promotional stimuli among their subordinate factors. Questionnaires were distributed 340 women who aged between 20 and 30. A sample of 317 women responded to the questionnaire. Using SPSS/PC version 12.0, factor analysis reliability analysis, Analysis of Variance (ANOVA), and Repeated measure ANOVA were used for the data analysis. As results, there were significant differences in importance of buying motives including external stimuli and sales promotional stimuli among groups according to levels of diversity orientation. Also, there were significant differences in importance of external stimuli and sales promotional stimuli among their subordinate factors.