• Journal of the Semiconductor & Display Technology
• /
• v.16 no.2
• /
• pp.79-84
• /
• 2017

This paper outlines the Taguchi optimization methodology, which is applied to optimize cutting parameters in end milling when machining STS304 with TiAlN coated SKH59 tool under up and down end milling conditions. The end milling parameters evaluated are depth of cut, spindle speed and feed rate. An orthogonal array, signal-to-noise (S/N) ratio and analysis of variance (ANOVA) are employed to analyze the effect of these end milling parameters. The Taguchi design is an efficient and effective experimental method in which a response variable can be optimized, given various control and noise factors, using fewer resources than a factorial design. An orthogonal array of $L_9(33)$ was used. The most important input parameter for cutting force, however, is the feed rate, and depending on the cutter rotation direction. Finally, confirmation tests verified that the Taguchi design was successful in optimizing end milling parameters for cutting force.

• Journal of the Korean Recycled Construction Resources Institute
• /
• v.11 no.4
• /
• pp.535-541
• /
• 2023

Friction material, an integral constituent of bearing supports, facilitates frictional interactions between two components. Polytetrafluoroethylene (PTFE), a commonly employed friction material in bearing supports, has assessed resultant friction equilibrium. Nonetheless, protracted utilization diminishes frictional performance as the lubricating agent is progressively depleted. Friction materials can affect the entire structural system. Hence, this study applied ceramic material as a friction material due to its high strength, low friction, and low deformation. The frictional behavior was investigated using a cyclic friction test, considering various friction materials as the primary design variables and examining their covariance in cyclic frictional movements. The results substantiated that the ceramic friction material yielded a low variance and friction coefficients in cyclic frictional movements.

• Journal of the Korean Society of Safety
• /
• v.37 no.1
• /
• pp.20-29
• /
• 2022

To stem the ever-prevalent occurrence of industrial accidents in the construction industry, which is emerging as a social problem, efforts must be invested by various stakeholders. Specifically, among stakeholders, the orderer is at the top of a project's decision-making structure. Therefore, the orderer's awareness of safety and health directly affects the process of securing the safety of the overall construction site. In this light, the present study aims to identify differences in the perceptions of each stakeholder regarding the obligatory safety and health measures for clients that have recently been introduced. In addition, it suggests specific implementation plans in the Korean context. The data used for analysis were collected through a survey targeting stakeholders such as orderers, safety managers, and site managers, and the collected data were quantitatively reviewed by using multivariate analysis methods such as analysis of variance. As a result of the analysis, the introduction of safety and health obligations for the owner was found to be necessary, and the designation and operation of safety and health experts as an action plan was deemed reasonable. The authors expect that the results of this study can be used as basic data for revising the related regulations in Korea. Moreover, as a further study, a review of the effectiveness after improving regulations would contribute strongly to the domain.

• International Journal of Industrial Entomology and Biomaterials
• /
• v.3 no.1
• /
• pp.31-35
• /
• 2001

Ten newly evolved bivoltine hybrids of silkworm (Bombyx mori L) were evaluated with control hybrid KA${\pm}$NB4D2 during three seasons of a year for their seasonal performance. Analysis of variance and other statistical methods were employed and the performance was observed in respect of 10 quantitative traits. The results showed significant genotype${\pm}$environment interaction with respect to four quantitative characters viz. fecundity, yield/10,000 larvae, filament length and raw silk (%). Environmental effects were significant for nine characters out of ten characters evaluated. A 105${\pm}$J2 and B${\pm}$NB4D2 were considered as highly adaptable hybrids to local conditions with high mean for maximum characters studied and found suitable to rear in all seasons.

• Transactions on Electrical and Electronic Materials
• /
• v.9 no.6
• /
• pp.237-242
• /
• 2008

The effects of the process parameters in the molding of aspheric glass lenses for camera phone modules have been investigated experimentally. The molding conditions were optimized with respect to the form accuracy (PV) (the response variable) of the molded lens. The experimental conditions were obtained by employing a factorial design method. From the analysis of variance (ANOVA) and P-value (significance level), the slow cooling rate was found to affect the response variable most significantly. The lens molded under the optimum molding condition showed a transcription ratio of 93.4%.

• 보존과학연구
• /
• s.8
• /
• pp.1-12
• /
• 1987

Fifty ancient Korean coins originated in Choson dynasty have been determined for 9 elements such as Sn, Fe, As, Ag, Co, Sb, Ir, Ru and Ni by instrumental neutron activation analysis and for 3 elements such as Cu, Pb, and Zn by atomicalsorption spectrometry. Bronze coins originated in early days of the dynasty contain as major constituents Cu, Pb and Sn approximately in the ratio 90 : 4 : 3, where as, those in latter days contain in the ratio 7 : 2 : 0. Brass coins which had begun in 17century contain as major constituents Cu, Zn and Pb approximately in the ratio 7 : 1: 1. The multivariate date have been analyzed for the relation among elemental contents through the variance-covariance matrix. The data have been fur theranalyzed by a principal component mapping method. As the results training set of 8class have been chosen, based on the spread of sample points in an eigenvector plotand archaeolgical data such as age and the office of minting.

• Journal of the Korean Home Economics Association
• /
• v.35 no.4
• /
• pp.111-124
• /
• 1997

The purpose of this study was to find out the effects of children's elementary school entrance age and sex on cognitive and social abilities. The subjects were 80 the same number was slected by elementary school entrance age(5-year and 6-year) and sex. Their cognitive and social abilities were measured by Intelligence Maturity Test and Revised Vineland Adaptive Behavior Scales. The data were statistically analyzed including descriptive statistics and multivariate analysis of variance. The results were as follows: 1) 6-year-old children had higher perceptive ability of sameness and calculation ability than 5-year-old children. Girls also had higher IQ and language concept than boys, 2) 6-year-old children's communication socialization and total social ability were higher than those of 5-year old children Girls' communication and total social ability were higher than those of boys. The implication was that it would be important to consider children's social ability if their entrance age were decided. In addition Early Entrance to Elementary School system should be reconsidered in the point of childer's developmental adaptation.

• Journal of Magnetics
• /
• v.15 no.2
• /
• pp.74-77
• /
• 2010

This paper deals with optimum design criteria for maximum torque density & minimum torque ripple of a Flux Switching Motor (FSM) using response surface methodology (RSM) & finite element method (FEM). The focus of this paper is to find a design solution through the comparison of torque density and torque ripple which vary with rotor shape. And then, a central composite design (CCD) mixed resolution was introduced and analysis of variance (ANOVA) was conducted to determine the significance of the fitted regression model. The proposed procedure allows one to define the rotor dimensions, starting from an existing motor or a preliminary design.

• Women's Health Nursing
• /
• v.15 no.3
• /
• pp.216-223
• /
• 2009

Purpose: The purpose of this study was to investigate the influencing factors of postpartum depression among parturient women between 4 to 6 weeks after childbirth. Methods: The participants were 146 healthy postpartum women who delivered at three women's health hospitals in Chungnam province in 2008. Data were collected by a self-report questionnaire. Collected data were analyzed by using the SPSS WIN 14.0 program. Results: There was a significant difference in postpartum depression depending on the educational level. Postpartum depression was significantly correlated with childcare stress, social support, infant fussiness, Sanhujori satisfaction, subjective health condition, and sleep satisfaction. Stepwise multiple regression analysis showed that postpartum depression was significantly predicted by childcare stress, Sanhujori satisfaction and subjective health condition. These variables explained 49.0% of the variance of postpartum depression. Conclusion: It is concluded that a nursing intervention for postpartum depression should focus on decreasing childcare stress and improving Sanhujori satisfaction. further studies are required to verily and substantiate the effect of the developed nursing intervention programs.

• Journal of Korean Society for Quality Management
• /
• v.43 no.2
• /
• pp.169-184
• /
• 2015

Purpose: This paper is concerned with optimally designing accelerated degradation test (ADT) plans based on a gamma process for the degradation model. Methods: By minimizing the asymptotic variance of the MLE of the q-th quantile of the lifetime distribution at the use condition, the test stress levels and the proportion of test units allocated to each stress level are optimally determined. Results: The optimal plans of ADT are developed for various combination of parameters. In addition, a method for determining the sample size is developed, and sensitivity analysis procedures are illustrated with an example. Conclusion: It is important to optimally design ADT based on a gamma process under the condition that a degradation process should be always nonnegative and strictly increasing over time.