• 한국초전도ㆍ저온공학회논문지
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• 제8권1호
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• pp.23-25
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• 2006

Optimization of process variables, including oxygen and water partial pressure and also an nesting temperature, was performed in batch-type process to fabricate YBCO films on LaAlO3 single crystal. In this work, YBCO oxide powder was used as a starting precursor for metal-organic deposition(MOD)method. The precursor films were fabricated in batch furnace and they were converted to the epitaxial YBCO films at the same furnace with varying the process variables. The oxygen partial pressure was varied from 100ppm to 2000ppm and the water partial pressure from 1.2% to 12.2%. The window for optimal P(O2) was narrow about 700ppm for batch-type process. YBCO films in bathc-thype MOD process were optimized at 740-770oC and P(H2O) of 2.3%-7.3%.

• 대한화학회지
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• 제56권2호
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• pp.257-263
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• 2012

The selection of suitable delignification conditions and optimization of process variables is crucial to the successful operation of chemical pulping processes. Soda pulping of Carpolobia lutea was investigated, as an alternative raw material for pulp and paper production. The process was optimized under the influence of three operational variables, namely, temperature, time and concentration of cooking liquor. Equations derived using a second - order polynomial design predicted the pulp yield and lignin dissolution with errors less than 8% and 11% respectively. The maximum variations in the pulp yield using a second order factorial design was caused by changes in both time and alkali concentration. Optimum pulp yield of 43.87% was obtained at low values of the process variables. The selectivity of lignin dissolution was independent of the working conditions, allowing quantitative estimations to be established between the pulp yield and residual lignin content within the range studied.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1996년도 춘계학술대회논문집
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• pp.23-30
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• 1996

The purpose of this study was to investigate changes in thewall thickness of tube sinking and working forces by the upper bound method and ABAQUS code. The independent variables were : Workpiece material, original wall thickness of tube, die angle, friction, and diameter reduction. The results indicated that of these five variables were a factor in wall-thickness increase and working forces. Three variables, a inner tube wall angle and two angles of the velocity discontinuous surfaces, are optimized in this proposed velocity field by the upper bound method. In this method, we can estimate the working forces and final tube thicknesses whcih are similar to acturla forming process. Optimized process variables which are obtained by upper bound method are used in ABAQUS pre-model . In ABAQUS analysis, the stress and the strain contours which are considered to be heat generation occured by the friction during forming process are observed.

• 한국초등과학교육학회지:초등과학교육
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• 제20권1호
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• pp.1-7
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• 2001

The purpose of this study is to examine the learner's variables affecting on scientific thinking and scientific process skills. To study this purpose, through the procedure study, the learner's variables were divided into cognitive variable, ego variable, and affective variable, then the questionaire survey through the reconstruction of standardization instrument was made over 120 elementary school fifth grade student in Seoul, Anyang, and Pajoo. The results of this study were as follows: 1) The learner's variables affecting on scientific thinking were cognitive variable and for female students, also affect affective variable. The subordinated catagories of statistically significant degree of explanation were achievement motivation, cognitive level, and cognitive style and another statistically significant correlation were meta-cognition, self regulated learning, self efficacy, and muliple intelligence. 2) The learner's variables affecting on science process skills were cognitive variable and affective variable. And the subordinated catagories of statistically significant degree of explanation were achievement motivation, and cognitive level. And another statistically significant correlation were meta-cognition, self regulated loaming, self efficacy, multiple intelligence, and attribution.

• 품질경영학회지
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• 제28권3호
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• pp.155-164
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• 2000

This paper considers the problem of determining the optimum proccss mean value of the quality characteristic of interest, and the screening limit for two correlated variables under single-stage screening. In the single-stage screening, inspection is performed on two correlated variables which are correlated with the quality characteristic of interest. Model is constructed which involves selling price, production, inspection, and penalty costs. Method for finding the optimum process mean and screening limit are presented when the quality characteristic of interest and the correlated variables are assumed to be jointly normally distributed. A numerical example is presented and numerical analysis is performed to compare the proposed screening based on two screening variables with screening based on one screening variable.

• Journal of Welding and Joining
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• 제15권6호
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• pp.116-123
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• 1997

In GMA welding processes, bead contour and penetration patterns are criterion to estimate weld quality. Bead geometry is commonly defined with width, height and depth. When weaving is taken into account, selection of welding conditions is known to be difficult. Thus, empirical or trial-and-error method are usually introduced. This study examined the correlation of welding process variables including weaving parameters with bead geometry using srtificial neural networks(ANN). The main task of the Ann estimator is to realize the mapping characteristics from the sampled welding process variables to the actual bead geometry through training. After the neural network model is constructed, welding process variables for desired bead geometry is selected by inverse model. Experimental varification of the inverse model is conducted through actual welding.

• 대한산업공학회지
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• 제29권4호
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• pp.334-344
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• 2003

A mixture experiment is a special type of response surface experiment in which factors are the ingredients or components of a mixture, and the response is a function of the proportions of each ingredient. Evolutionary operation is useful to improve on-line full-scale manufacturing process by systematically changing the levels of the process variables without jeopardizing the product. This paper presents an evolutionary operation procedure with mixture variables for large-scale mixture production process which can be beneficial to practitioners who should improve on-line mixture quality while maintaining the production amount of the mixture product.

• 가정과삶의질연구
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• 제20권1호
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• pp.115-124
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• 2002

The purpose of this study is to examine the social competence of children with reference to day care center's structural, process variables and demographic variables. The subjects were 156 children who attend day care center, aged from 3 to 5 years and 9 teachers in Seoul or the province of KyungkiDo. Data were gathered via the structured Questionnaires distributed to the teachers to rate children's social competence and their own job satisfaction. And two observers rated teacher-child interaction in day care center The major findings are as follows The variables predicting children's social competence were child's sex, age, period of attendance in day care center, teacher's job satisfaction, and group size. Especially this study suggests that teachers who are highly satisfied with their job and small group size influence children's social competence positively.

• 제어로봇시스템학회논문지
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• 제8권10호
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• pp.847-850
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• 2002

Stochastic process analysis is often based on Monte Carlo simulations. As a more rigorous alternative, a deterministic algorithm based on numerical integration is proposed in this paper. which calculates the probability distributions of dependent random variables using the results of simulation with grid points of independent random variables. For performance evaluation, the proposed algorithm is applied to an example problem which can be analytically solved. and the result is compared with that of Monte Carlo simulation. The proposed algorithm is suitable for general process simulation problems with a few independent random variables, and expected to be applicable to areas such as safety analysis and quality control.

• 호남수학학술지
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• 제36권3호
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• pp.679-688
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• 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.