• The Korean Journal of Applied Statistics
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• v.23 no.2
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• pp.235-247
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• 2010

In this paper it is investigated how the number of work experiences is distributed among college graduates who have ever entered the labor market and built up career by turnover. To do so, we classified the type of work experience and, moreover, conduct ANOVA to explore wage differentials caused by the number of work experience and by the type of work experience, using the GOMS(graduates occupational mobility survey) from 2006 to 2007.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.19 no.2
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• pp.184-190
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• 2010

Recently, the polishing process using magnetorheological fluids(MR fluids) has been focused as a new ultra-precision polishing technology for micro and optical parts such as aspheric lenses, etc. This method uses MR fluid as a polishing media which contains required micro abrasives. In the MR polishing process, the surface roughness and material removal rate of a workpiece are affected by the process parameters, such as the properties of used nonmagnetic abrasives(particle material, size, aspect ratio and density, etc.), rotating wheel speed, imposed magnetic flux density and feed rate, etc. The objective of this research is to predict MRR according to the polishing conditions based on the multiple regression analysis. Three polishing parameters such as wheel speed, feed rates and current value were optimized. For experimental works, an orthogonal array L27(313) was used based on DOE(Design of Experiments), and ANOVA(Analysis of Variance) was carried out. Finally, it was possible to recognize that the sequence of the factors affecting MRR correspond to feed rate, current and wheel speed, and to determine a combination of optimal polishing conditions.

• Journal of the Korean Society for Railway
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• v.16 no.2
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• pp.144-150
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• 2013

This paper presents an analysis of door design for the Ui LRT based on experiments to predict doorway flow-time and their analyses results. A similar railway vehicle (from Gimhae LRT) and operational conditions are utilized to assess the doorway flow-time through repetitive experiments. Design of the experiments consists of four scenarios, and the experiments are repeated 39 times in total. We use the results of the experiments to verify the design of doors of Ui LRT (e.g. the required number of doors and their width). Various statistical analyses are carried out for the flow-time with respect to the number of boarding/alighting passengers. We make three category levels of boarding/alighting passengers, and analyze the mean and variance for each category, and then carry out One-Way ANOVA to analyze how the number of boarding/alighting and onboard passengers impact flow-time. The results of this paper can be used for making decisions about doors of the LRT vehicle.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.21-27
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• 2013

Recently, It is increasing that importance of systematic management by carbon sinks in forest resources. Especially, in terms of social, Forest resources in urban areas are important role as well as carbon sinks, and improvement of the natural environment of the city. In this study, through ANOVA analysis that a total of nine different vegetation index from rearranged NIR band of images to Forest tree species classified in urban areas using high-resolution aerial images and satellite images of KOMPSAT-2. And various vegetation indices such as NDVI are divided a species by forest units through statistical analysis. Also, separated species are compared to forest type map by the Forest Service. As a result, it is built as basis for vegetation management in urban areas.

• Journal of Digital Convergence
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• v.19 no.9
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• pp.307-316
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• 2021

This study aims to explore the effects of deductive FFI and inductive FFI in L2 learners' grammatical achievement and their reaction to the grammar instruction. 84 students were placed into three groups: 29 given deductive FFI(DG), 28 receiving inductive FFI(IG), and 27 with traditional instruction(CG). All students completed pre/post tests and questionnaires, and took a delayed post test 9 weeks after the treatment. For statistical anlayses of all the quantitative data, a one-way ANOVA, paired samples T-test, and repeated measures ANOVA were performed. The results indicated that both deductive and inductive FFI affected learners' grammatical achievement and their achievement was sustained over time. Deductive FFI was more effective than inductive FFI, whereas the IG students more positively changed their attitudes and perceptions to the grammar instruction. These findings of the study imply that FFI should be valued in an Korean EFL classroom, which would contribute to further longitudinal research for its sustainability.

• Journal of the Korean Data and Information Science Society
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• v.25 no.4
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• pp.755-767
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• 2014

Recently, many firms have introduced information and communication technology (ICT) into supply chain. However, existing studies have not yet insisted definite conclusion with respect to ICT impact on supply chain. Thus, this study subdivides supply chain performance which previous researchers have studied comprehensively while suggesting perspective of the use of firm's ICT capabilities. We classify ICT capabilities into four types of group and then analyze the difference between groups regarding each factor of supply chain performance by ANOVA analysis and Tukey method. As a result of analysis, the group in which all ICT capabilities are high shows the highest level of integration and flexibility performance among supply chain performances. On the other hand, the group in which all ICT capabilities are low presents the lowest level of integration and flexibility performance. We also provide more precise and specific information with practitioners by analyzing the difference between groups with regard to detailed measurements on integration and flexibility variables.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.298-303
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• 2004

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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.694-697
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• 2005

The design of experiments are used for optimal design of formed tools to machine automobile bearing rubber seal die, which is classified into the high precision rubber mold. The clearance angle, rake angle and the length cutting edge are considered as the factors. The cutting force is selected to be a characteristic value and compared with the mean tool wear and life by repeated experiments. The design of the experiment is based on the repeated one-way factorial design, which finds the significance of the factors and the best level to predict the tool life by using ANOVA and regression.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.866-869
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• 2000

To improve quality of the ground surface, we have to consider a number of parameters. But it is difficult to make experiment with many parameters. Most of all experiments try to search optimal grinding condition with conservative factors such as feed rate, depth of cut, wheel rotating speed, etc. But This paper attempts to view the significance of some different factors effecting on the surface roughness by introducing helical scan grinding method and material removal rate. The design of experiment is used to find the optimal grinding condition which minimizes the surface roughness value bout optical glass material. To analyze experimental results, ANOVA(ANalysis of VAriation) is used. Discussion on the result about helical scan grinding is also given.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.553-556
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• 2003

End-milling have been used in the industrial world because it is very effective to the manufacture of mechanical parts with various shape. Recently the end-milling processing is needed the high-precise technique with good surface roughness and rapid time in aircraft, automobile part and molding industry. Therefore this study carried to decide the optimum cutting condition for surface roughness and rapid manufacturing time using design of experiment and ANOVA. From the results of experimentation, surface roughness have an effect on cutting direction, spindle speed and depth of cut. And then the optimum condition used Taguchi design is upward cutting in cutting direction, 600rpm in spindle speed, 240mm/min feed rate, 2mm in axial depth of cut and 0.25mm radial depth of cut. By using design of experiment, it is effectively represented shape characteristics of working surface in end-milling.