• Journal of Korean Society for Quality Management
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• v.46 no.3
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• pp.509-522
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• 2018

Purpose: The purpose of this study was to propose more accurate mathematical model which can represent result of government quality assurance activity, especially corrective action and flaw. Methods: The collected data during government quality assurance activity was represented through histogram. To find out which distributions (Poisson distribution, Zero-Inflated Poisson distribution) could represent the histogram better, this study applied Pearson's correlation coefficient. Results: The result of this study is as follows; Histogram of corrective action during past 3 years and Zero-Inflated Poisson distribution had strong relationship that their correlation coefficients was over 0.94. Flaw data could not re-parameterize to Zero-Inflated Poisson distribution because its frequency of flaw occurrence was too small. However, histogram of flaw data during past 3 years and Poisson distribution showed strong relationship that their correlation coefficients was 0.99. Conclusion: Zero-Inflated Poisson distribution represented better than Poisson distribution to demonstrate corrective action histogram. However, in the case of flaw data histogram, Poisson distribution was more accurate than Zero-Inflated Poisson distribution.

• Tribology and Lubricants
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• v.38 no.3
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• pp.84-92
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• 2022

In Part I, developed was a method to obtain the stress field due to an edge dislocation that locates in an elastic half plane beneath the contact edge of an elastically similar square wedge. Essential result was the corrective functions which incorporate a traction free condition of the free surfaces. In the sequel to Part I, features of the corrective functions, F_kij,(k = x, y;i,j = x,y) are investigated in this Part II at first. It is found that F_xxx(ŷ) = F_xyx(ŷ) where ŷ = y/η and η being the location of an edge dislocation on the y axis. When compared with the corrective functions derived for the case of an edge dislocation at x = ξ, analogy is found when the indices of y and x are exchanged with each other as can be readily expected. The corrective functions are curve fitted by using the scatter data generated using a numerical technique. The algebraic form for the curve fitting is designed as F_kij(ŷ) = $\frac{1}{\hat{y}^{1-{\lambda}}I+yp}$$\sum_{q=0}^{m}{\left}$$\left[A_q\left(\frac{\hat{y}}{1+\hat{y}} \right)^q \right]$ where λ_I=0.5445, the eigenvalue of the adhesive complete contact problem introduced in Part I. To investigate the exponent of F_kij, i.e.(1 - λ_I) and p, Log|F_kij|(ŷ)-Log|(ŷ)| is plotted and investigated. All the coefficients and powers in the algebraic form of the corrective functions are obtained using Mathematica. Method of analyzing a surface perpendicular crack emanated from the complete contact edge is explained as an application of the curve-fitted corrective functions.

• Earthquakes and Structures
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• v.25 no.3
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• pp.177-186
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• 2023

Reinforced concrete frames with a masonry infill panel is a structural typology frequently used worldwide. In seismic cases, the interaction between the masonry infill and the RC frames constitutes one of the most complex subjects in earthquake engineering. In this work, an enhancement of an existing numerical model is proposed to improve the estimation of lateral strength and stiffness of masonry-infilled frame structures and predict their probable failure modes. The proposed improvement is based on attributing corrective coefficients to the shear strength of each diagonal shear spring of the macro element, which simulates the masonry infill. The improved numerical model is validated by comparing the results with those of the original numerical model and with experimental results available in the literature. The enhanced macro element model can be used as a powerful, accessible tool for assessing the capacity and stiffness of masonry-infilled frame structures and predicting their probable failure modes.

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.3
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• pp.359-365
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• 1998

An economic process monitoring procedure is presented when the major quality characteristic of the item is dichotomous. Every item is inspected and decided whether it is conforming or not. If an item is found to be nonconforming, the previous number of the successive conforming items is compared with a predetermined number r to check the process for existence of any assignable cause of variation. A cost model is constructed on the basis of costs of inspection, illegal signal, undetected out-of-control state and corrective action. By minimizing the expected total cost per unit time, the optimal value of r is obtained. The effects of cost coefficients are studied numerically.

• Korean Journal of Community Nutrition
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• v.8 no.4
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• pp.603-609
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• 2003

This study examined the reproducibility of nutrient intakes estimated by the 24-hour recall method in a prospective cohort study (Longitudinal study of aging and health monitoring of Korean elderly) of middle-aged volunteer subjects (42 males and 49 females) in the Seoul area. The three-day 24-hour recall was administered twice at an interval of approximately 6 months. The first data were collected and a corrective procedure was performed by interviewing of the subjects and a trained dietitian. The second data were collected by mail from the subjects without the performance of any corrective procedure. The mean age of the subjects was 53.5 $\pm$ 9.6 for the males and 52.2 $\pm$ 8.9 for the females. The subjects who had above college education were 95% in the case of the males and 60% in the case of the females. The characteristics of the male subjects in this study were that they were highly educated and held professional jobs and were from the middle or upper class. Comparing the first and second 24-hour recall data, the second data showed relatively lower intakes of all nutrients, except vitamin A, vitamin Bi and cholesterol. There was no difference in the nutrients of the first and the second data with respect to vitamin A, vitamin B$_1$ and cholesterol in the males and calcium, iron, sodium, vitamin A, vitamin B$_1$, vitamin B$_2$ and cholesterol in the females. This data may indicate that the 24 hour retail method without a dietitian's help may result in lower reporting of the subject's intakes. The men had a tendency to remember less than the women. Pearson's correlation coefficients with unadjusted nutrient intakes values were ranged from 0.24 to 0.66. When energy intake was adjusted, there was a slight increase (from 0.26 to 0.71). Intra-class correlation coefficients with nutrient-unadjusted values ranged from 0.22 to 0.66, and the energy-adjusted values were ranged from 0.23 to 0.69. The weighted Kappa statistical values ranged from 0.10 to 0.40. On the average,46.3% of the subjects who were found in the lowest quartile of the nutrient intake levels based on the first 24-hour recall, were in the lowest quartile based on the second 24-hour recall. Therefore, there was a low reproducibility between the first and the second 24-hour recall. We should examine the factors influencing low reproducibility. Also, strategies should be developed to maximize the reliability of the assessment, with regard to portion-size training and telephone validation. (Korean J Community Nutrition 8(4) : 603∼609, 2003)

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3059-3072
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• 2022

A Jacobian-Free Newton Krylov Two-Nodal Coarse Mesh Finite Difference algorithm based on Nodal Expansion Method (NEM_TNCMFD_JFNK) is successfully developed and proposed to solve the three-dimensional (3D) and multi-group reactor physics models. In the NEM_TNCMFD_JFNK method, the efficient JFNK method with the Modified Incomplete LU (MILU) preconditioner is integrated and applied into the discrete systems of the NEM-based two-node CMFD method by constructing the residual functions of only the nodal average fluxes and the eigenvalue. All the nonlinear corrective nodal coupling coefficients are updated on the basis of two-nodal NEM formulation including the discontinuity factor in every few newton steps. All the expansion coefficients and interface currents of the two-node NEM need not be chosen as the solution variables to evaluate the residual functions of the NEM_TNCMFD_JFNK method, therefore, the NEM_TNCMFD_JFNK method can greatly reduce the number of solution variables and the computational cost compared with the JFNK based on the conventional NEM. Finally the NEM_TNCMFD_JFNK code is developed and then analyzed by simulating the representative PWR MOX/UO₂ core benchmark, the popular NEACRP 3D core benchmark and the complicated full-core pin-by-pin homogenous core model. Numerical solutions show that the proposed NEM_TNCMFD_JFNK method with the MILU preconditioner has the good numerical accuracy and can obtain higher computational efficiency than the NEM-based two-node CMFD algorithm with the power method in the outer iteration and the Krylov method using the MILU preconditioner in the inner iteration, which indicates the NEM_TNCMFD_JFNK method can serve as a potential and efficient numerical tool for reactor neutron diffusion analysis module in the JFNK-based multiphysics coupling application.

• Journal of Chest Surgery
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• v.23 no.1
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• pp.22-32
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• 1990

Postoperative cardiac performance of cyanotic congenital heart disease is somewhat different from that of other cardiac diseases. For the evaluation of postoperative cardiac performance in the cyanotic congenital heart disease we measured cardiac output by thermodilution technique at 1, 4, 8, 12, 16, 20, 24, 36, 48 postoperative hours in 14 patients operated from Feb. 1989 to Nov. 1989 in The Department of Thoracic and Cardiovascular Surgery, Seoul National University Children`s Hospital. At the same time, we checked left atrial pressure [LAP], central venous pressure [CUP], and mixed venous oxygen saturation [SvO2] to detect correlation between them. Immediate postoperative cardiac index was 3.585 $\pm$ 0.945 L/min/m2, and it decreased maximally to 3.322$\pm$1.007 L/min/m2 at postoperative 16 hours. After then it increased and stabilized from 36 hours after operation, and its value was 4.426$\pm$1.358 L/min/m2. There were no correlations between cardiac index and left atrial pressure or central venous pressure. Between mixed venous oxygen saturation and cardiac index, there was no correlation in the early postoperative period but after postoperative 16 hours, there was significant correlation between them and correlation coefficients were 0.573 [16hrs], 0.743 [20hrs], 0.436 [24hrs], 0.560 [36hrs], 0.636 [48hrs], respectively. From these results, we concluded that in the corrective surgery of cyanotic congenital heart disease, cardiac performance was depressed in the early postoperative period. It improved from postoperative 16 hours, and stabilized from 36 hours after operation. During early postoperative period, mixed venous oxygen saturation should not be used as a predictor of cardiac performance but it could be used as a predictor of cardiac performance from 16 hours after operation.

• Journal of Digital Convergence
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• v.14 no.12
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• pp.257-265
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• 2016

This study is the descriptive survey to understand the knowledge, attitude, and education needs of the university students on the dementia and to examine their relationships. Collected data were analyzed using t-test, ANOVA, and Pearson's correlation coefficients with the SPSS 20.0 for Windows Program. The rate of corrective answers on dementia was shown as 79.6%, mean attitude with 3.74 points, and mean education needs with 4.02 points. Significant positive correlations were detected between the knowledge and the attitude (r=.23, p=.005), and between the attitude and education needs (r=.61, p<.001). Based on the results of this study, it is required to make an effort to enhance the correct knowledge of the university students on dementia and to establish their positive attitude. The objective education needs proven by this study are expected to be used as the fundamental data for the development of customized education program for the university students.