• Journal of the Korean Society of Manufacturing Process Engineers
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• v.3 no.4
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• pp.13-19
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• 2004

This paper deals with the analysis of geometric error and the optimization of process parameters in surface grinding. Taguchi method which is one of the design of experiments has been introduced in achieving the aims. The process parameters were the grain size, the wheel speed, the depth of cut and the table speed. The effect of the process parameters on the geometric error was examined and an optimal set of the parameters was selected to minimize the geometric error within the controllable range of the used grinding machine. The reliability of the results was evaluated by the ANOVA.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.6
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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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• v.7 no.1
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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).

• Journal of the Korea Safety Management & Science
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• v.12 no.3
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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.

• Korean Journal of Child Studies
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• v.21 no.3
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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.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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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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• v.39 no.2
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• pp.143-147
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• 2014

• Restorative Dentistry and Endodontics
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• v.39 no.1
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• pp.74-77
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• 2014

• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.1
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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.

• The Korean Journal of Applied Statistics
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• v.24 no.2
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• pp.373-381
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• 2011

This paper discusses how to get the sums of squares due to treatment factors when Type I Analysis is used by projections for the analysis of data under the assumption of a two-way ANOVA model. The suggested method does not need to calculate the residual sums of squares for the calculation of sums of squares. There-fore, the calculation is easier and faster than classical ANOVA methods. It also discusses how eigenvectors and eigenvalues of the projection matrices can be used to get the calculation of sums of squares. An example is given to illustrate the calculation procedure by projections for unbalanced data.