• Honam Mathematical Journal
• /
• v.36 no.3
• /
• pp.679-688
• /
• 2014

The notion of asymptotically negative dependence for collection of random variables is generalized to a Hilbert space and the almost sure convergence for these H-valued random variables is obtained. The result is also applied to a linear process generated by H-valued asymptotically negatively dependent random variables.

• Proceedings of the Korean Society for Quality Management Conference
• /
• 2006.04a
• /
• pp.330-333
• /
• 2006

Many practical problems of quality control in service management are derived from the use of ordinal variables. Ordered linguistic variables differ from measurement variables. This paper presents a new control chart of a production process based on ordinal variables.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2004.10a
• /
• pp.1082-1086
• /
• 2004

Since the sheet forming of Mg alloy has many difficulties due to the low formability, many forming conditions need to be selected properly. Especially, the process variables should be investigated to increase the formability, such as, forming temperature. In this paper, the effects of forming process variables has been investigated using the bending and deep drawing process. A simple U-bending designed for mobile part could be formed in room temperature and springback amounts are surveyed. On the other hand, square cup part couldn't be formed in room temperature due to the low formability. Therefore, the effects of forming temperature are investigated in deep drawing process for square cup part. As a experimental and FEM results, the optimum forming temperature is presence and formability in a higher temperature is less than that of lower temperature. Above experimental results are compared with the FEM analysis and well coincided with the experimental results. Therefore, more detail investigations could be progressed to select more appropriate process conditions by the FEA.

• Transactions of Materials Processing
• /
• v.9 no.5
• /
• pp.469-477
• /
• 2000

Most of researches have been performed on the formability of axisymmetric shape, but it is insufficient that the study on Process variables of elliptical deep drawing Product. There are many Process variables exerted influence on the formability of products. Particularly, blank shape is more important than the others in elliptical deep drawing process. In this study, blanks of three types were proposed and compared using thickness distribution and movement of sheet during the process. The aim of a paper is to obtain optimal blank shape through experiment and finite element analysis(FEA).

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2000.04a
• /
• pp.146-150
• /
• 2000

there are a lot of process variable exerted influence on the formability of products in deep drawing process. Particularly it is important that blank shape of the process variables. A paper to be connected with process variables of elliptical deep drawing products is insufficient the actual circumstances enough though researches have been performed on the deep drawing of sheet metal forming. In this study The effects of thickness distribution and movement of sheet are grasped as alteration of blank shapes in the process of elliptical deep drawing product and then optimal blank shape was presented. They were verified by the finite element analysis (FEA) and experiment.

• Journal of the Korean Home Economics Association
• /
• v.26 no.3
• /
• pp.33-42
• /
• 1988

The study was to investigate the relationship between clothing variables (Conformity, Modesty, Importance) and environmental variables of Family (the Value Orientations of Family, the Psychological Process of Family), according to sex and region. the subjects were university students in Kyoung nam and Pusan (Male; 397-Pusan 183 and Kyoung nam 214, Female; 401-Pusan 224 and Kyoung Nam 177). Survey method was questionnaires. The data was analyzed with frequency, Pearson's Parson's Correlation, T-test, Multiple Regression using the SPSS. The results were as follows; 1. There was significant difference between clothing Variables in Young nam, but partially significant difference in Pusan. 2. There was partially significant difference between clothing Variables and Environmental Variables of family in each male & female Kyoung nam & Pusan). 3. In the T-test, between clothing Variables and Environmental Variables of family, difference between male and female was shown that female student was higher than male student all of Clothing Variables and male student was higher than female student t in the case of Environmental Variables of family, In the difference between Pusan and Kyoung Nam, male student was shown significant difference in the case of Conformity, materialism and love-Rejection, female student in the case of Modesty, Importance, materialism and Social rising. 4. In the multiple Regression analysis between clothing variables and Environmental Variables of family, clothing voriables partially were effected on the Environmental Variables of family in the cases of male and female in Pusan & Kyoung Nam.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.10a
• /
• pp.754-758
• /
• 2005

Optimization of process variables such as arc current, welding voltage and welding speed in terms of the weld characteristics desired is the key step in achieving high quality and improving performance characteristics without increasing the cost. Consequently, incorrect settings of those process variables give rise to deviations in the welding characteristics from the desired bead geometry. Therefore, trainee welders are referred to the tabulated information relating different metal types and thickness as to recommend the desired values of process variables. Basically, the bead geometry plays an important role in determining the mechanical properties of the weld. So that it is very important to select the process variables for obtaining optimal bead geometry. However, it is difficult for the traditional identification methods to provide an accurate model because the optimized welding process is non-linear and time-dependent. In this paper, the possibilities of the Infra-red sensor in sensing and control of the bead geometry in the automated welding process are presented. Infra-red sensor is a well-known method to deal with the problems with a high degree of fuzziness so that the sensor is employed to build the relationship between process variables and the quality characteristic the proposed above respectively. Based on several neural networks, the mathematical models are derived from extensive experiments with different welding parameters and complex geometrical features. The developed system enables to select the optimal welding parameters and control the desired weld dimensions during arc welding process.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2001.10a
• /
• pp.216-219
• /
• 2001

The production of fine wire through multi-pass wet wire drawing process would be impossible with no backtension at inlet of dies. Backtension is affected by many process parameters, such as dies reduction, coiling number of wire at capstan, machine constant, slip between wire and capstan, characteristic of lubricant and so on. Up to date, dies design and dies pass schedule of multi-pass wet wire drawing process have performed by trial and error of expert in the Industrial field without consideration of quantitative relation among process variables. Thus study investigates the multi-pass wet wire drawing process considering the relation among process variables, such as dies reduction, coiling number of wire at capstan, machine constant, slip between wire and capstan, etc. And analysis program which can analyze many important process values(drawing force, backtension force, slip rate, slip velocity rate, etc) for die design and dies pass schedule of multi-pass wet wire drawing process was developed.

• Transactions of Materials Processing
• /
• v.8 no.5
• /
• pp.449-453
• /
• 1999

Sheet metal forming process is a non-linearity problem which is affected by various process variables, such as geometric shape of punch and die, frictional characteristic, etc.. Therefore, the knowledge of the influence of the process variables is needed in the design of sheet metal working processes. In this paper, cylindrical cup drawing tests for blank holding force, punch speed and lubrication between sheet material and tool were carried out to investigate the influence upon sheet formability. Experimental results were discussed about the defects on the deformation behaviors during the forming process.

• Journal of Industrial and Engineering Chemistry
• /
• v.68
• /
• pp.117-123
• /
• 2018

Recently, aqueous method has attracted lots of attention because it enables the solution-processed metal oxide thin film with high electrical properties in low temperature fabrication condition to various flexible devices. Focusing the development of aqueous route, many researchers are only focused on metal oxide materials. However, for expansive application of the aqueous-based metal oxide films, the systematic study of performance change with process variables for the development of aqueous-based metal oxide insulator film is urgently required. Here, we propose importance of process variables to achieve high electrical-performance metal oxide insulator based on the aqueous method. We found that the significant process variables including precursor solution temperature and humidity during the spincoating process strongly affect chemical, physical, and electrical properties of $AlO_x$ insulators. Through the optimization of significant variables in process, an $AlO_x$ insulator with a leakage current value approximately $10^5$ times smaller and a breakdown voltage value approximately 2-3 times greater than un-optimized $AlO_x$ was realized. Finally, by introducing the optimized $AlO_x$ insulators to solutionprocessed $InO_x$ TFTs, we successfully achieved $InO_x/AlO_x$ TFTs with remarkably high average field-effect mobility of ${\sim}52cm^2V^{-1}\;s^{-1}$ and on/off current ratio of 106 at fabrication temperature of $250^{\circ}C$.