• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.21-31
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• 2008

response surface method (RSM) is widely used to evaluate th e extremely smal probability of ocurence or toanalyze the reliability of very complicated structures. Althoug h Monte-Carlo Simulation (MCS) technique can evaluate any system, the procesing time of MCS dependson the reciprocal num ber of the probability of failure. The stochastic finite element method could solve thislimitation. However, it is limit ed to the specific program, in which the mean and coeficient o f random variables are programed by a perturbation or by a weigh ted integral method. Therefore, it is not aplicable when erequisite programing. In a few number of stage analyses, RSM can construct a regresion model from the response of the c omplicated structural system, thus, saving time and efort significantly. However, the acuracy of RSM depends on the dist ance of the axial points and on the linearity of the limit stat e functions. To improve the convergence in exact solution regardl es of the linearity limit of state functions, an improved adaptive response surface method is developed. The analyzed res ults have ben verified using linear and quadratic forms of response surface functions in two examples. As a result, the be st combination of the improved RSM techniques is determined and programed in a numerical code. The developed linear adapti ve weighted response surface method (LAW-RSM) shows the closest converged reliability indices, compared with quadratic form or non-adaptive or non-weighted RSMs.

• Journal of the Korean Wood Science and Technology
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• v.35 no.1
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• pp.17-26
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• 2007

This study was conducted to investigate the effects of End-coating (CO) treatment and Vapor-dam (V) treatment on the air circulating oven drying characteristics of green stock (Paulownia tomentosa) for drum. The reduction of the weight of specimens was greatly displayed in order of control (C-NC) treatment, End-coating (C-CO) treatment, Vapor-dam (V-NC) treatment and Vapor-dam/End-coating (V-CO) treatment after the beginning of drying. The V-CO treated specimen showed smoother temperature gradient compared with the V-NC treated specimen throughout whole drying stage and there was little temperature gradient between the inner and outer part of the cylindrical stock. The C-CO treated specimen showed higher value of vapor pressure in both the inner and outer part of the cylindrical stock until the middle stage of drying, while after the middle stage of drying only the inner part of the cylindrical stock presented higher value compared with the C-NC treated specimen. The distribution of the absolute vapor pressure of the V-CO treated specimen was similar to that of the V-NC treated specimen during the initial stage of drying. However, the former showed a large distribution in order of the hollow, the outer part, the inner part of the cylindrical stock after the initial stage of drying, which was entirely different model of distribution from that of the V-NC treated specimen. Surface checks and ring failures were not observed for all of the specimens, while end checks were severely occurred for the C-NC treated specimen and the V-NC treated specimen.

• Childhood Kidney Diseases
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• v.14 no.1
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• pp.32-41
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• 2010

Purpose : Glomerulonephropathy (GN) often manifests as proteinuria and progresses to chronic renal failure without specific therapy. Mesenchymal stem cell (MSC) has been tried as a therapeutic agent in experimental GN, and previous studies showed that administration of MSC concomitantly to the insult inducing GN or via intra-renal administration ameliorated proteinuria. The purpose of this study was to test the therapeutic potential of MSC administered via intravenous route at the time of clinically evident proteinuria. Methods : MSCs were administered intravenously via tail vain into the mice with adriamycin (ADR) induced nephropathy (ADR-GN), two weeks after ADR injection when massive proteinuria was evident. To test the capacity of MSC modulate the cytokine production in the inflammatory milieu, the concentrations of IFN-$\gamma$ and IL-10 were measured in the supernatant of in vitro mixed lymphocyte culture (MLC) with or without additional MSC. Results : MSCs administered intravenously into the proteinuric mice with ADR-GN accelerated the recovery of this experimental GN with disappearance of proteinuria in two weeks when the saline treated (control) mice still showed significant proteinuria. The mice treated with MSC also had a tendency of better survival. Addition of MSC decreased IFN-$\gamma$ and increased IL-10 in the supernatant of MLC. Conclusion : This study showed that MSC had a therapeutic potential even when administered in a more clinically relevant setting into a proteinuric glomerulonephropathy model. Further study to verify the mechanism and long-term safety of this phenomenon is required.

• Journal of Yeungnam Medical Science
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• v.18 no.1
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• pp.85-93
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• 2001

Background: The number of glomerulus has been considered one of the etiologic factors especially for focal segmental glomerulosclerosis. However, glomeruli are too many to calculate them correctly. Although the fractionator method has became convinced, in which they used selected sections, not whole kidney sections, with same intervals, it is also very hard to get good results. Because it is still very time-consuming and laborous work which leads to make big observers' biases. Methods and Materials: We designed the index for glomerular number to estimate the tendency of increase or decrease of the number of it in different kidneys and which was evaluated by other conventional methods including fractionator method. Index was based upon the theory by Nyengaard; "the number of glomerulus correlates with the weight of kidney, which is positively correlated with body weight". Calculating formula is the number of glomeruli/surface areas of cortices, which contain calculated glomeruli multiplies by kidney weight/body weight. Results: We applied this index to kidneys of FGS/Kist mouse and those of RFM/Nga mouse. The former is spontaneous glomerulosclerosis model with heavy protein uria and renal failure and the latter is the mother side of FGS/Kist mouse but has no glomerular disease or protein uria. The number of glomerulus of FGS/Kist mouse was decreased by 30% to those of RFM/Nga mouse. Conclusion: This index was useful and reliable for estimating the relative glomerular number between two groups.

• The Journal of Korean Obstetrics and Gynecology
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• v.27 no.4
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• pp.69-87
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• 2014

Objectives: We analyzed retrospective clinical data of Korean medical institutes for infertility care and investigated current status and outcome of the Korean medical treatment of infertility as a part of foundational research for verifying validity of constructing national support system and developing appropriate policy on Korean medical treatment of infertility. Methods: We investigated data uploaded on the homepage of The Society of Korean Medicine for Subfertility (http://www.okinfertility.org) by Korean medical institutes for infertility care to get informations such as patients' age, body height, weight, methods of Korean medical treatment, cost and duration of treatment, success or failure of pregnancy and result of treatment. Results: The average age of patients was $33.1{\pm}3.8$ and the average body height was $161.2{\pm}5.3cm$ and the average body weight was $55.2{\pm}8.5kg$. The method of Korean medical treatment was Herbal medicine (97.5%), acupuncture (80.4%), moxibustion (57.7%), cupping (32.7%). The average cost of treatment was $1,160,625{\pm}882,499$ won, and the average medical cost per visit was $357,845{\pm}241,602$ won. The average duration of treatment was $11.26{\pm}10.58$ weeks, and the average number of visits per patient was $4.78{\pm}6.10$ times. The average duration of treatment was the longest in the group of infertile patients with the highest average medical cost per visit. The average pregnancy success rate was 30.9% overall, and that of the group of infertile patients was 25.8%. Conclusions: When we develop the standard project model with expectation for about 25% success rate of pregnancy and delivery in the group of patients who have idiopathic and ovulatory factors, it is desirable to perform acupuncture and moxibustion treatment 1-2 times a week with herbal medicine. The treatment period is set to at least 12 weeks. Average treatment fee maybe calculated by converting the averaged treatment cost of clinic's one month worth of daily treatment fee and medical hospital's ten day treatment fee into weekly treatment cost.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.5
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• pp.533-541
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• 2021

Retaining walls have been used to prevent slope failure through resistance of earth pressure in railway, road, nuclear power plant, dam, and river infrastructure. To calculate dynamic earth pressure and determine the characteristics for seismic behavior, many researchers have analyzed the nonlinear response of ground and structure based on various numerical analyses (FLAC, PLAXIS, ABAQUS etc). In addition, seismic fragility evaluation is performed to ensure safety against earthquakes for structures. In this study, we used the FLAC2D program to understand the seismic response of the inverted T-type wall with a backfill slope, and evaluated seismic fragility based on relative horizontal displacements of the wall. Nonlinear site response analysis was performed for each site (S2 and S4) using the seven ground motions to calculate various seismic loadings reflecting site characteristics. The numerical model was validated based on other numerical models, experiment results, and generalized formula for dynamic active earth pressure. We also determined the damage state and damage index based on the height of retaining wall, and developed the seismic fragility curves. The damage probabilities of the retaining wall for the S4 site were computed to be larger than those for the S2 site.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.441-456
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• 2021

Enterprise is focused on R&D innovative activities in order to achieve sustainable growth & secure competitive advantage. There are many factors that influence enterprise innovation performance, but enterprise innovation activities do not always have a positive effect. Therefore, this study analyzed the effects of on innovation performance, focusing on innovation acceleration factors and innovation hindrance factors. The research model analyzed 2,081 national manufacturing enterprises that responded to the 2016 Korean Innovation Survey (STEPI). SPSS 25.0 was used to perform reliability, feasibility, and logistic regression analysis. The results are as follows. First, innovation activities have positive effects on enterprise product and process innovation performance. On the other hand, government support had the opposite results. Second, the collaboration of technology showed a positive effect on product innovation performance, independent of innovation acceleration and hindrance factors. Third, innovation activities showed a positive effect on process innovation performance, regardless of the innovation acceleration and hindrance factors. Unlike prior studies limited to technological innovation, this study analyzed the attitudes of enterprises toward innovation acceleration and hindrance factors. This study is expected to contribute to establishing a strategy for reducing the failure and risk of innovation due to its findings on how innovation performance varies by groups.

• Korean Journal of Comparative Education
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• v.28 no.4
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• pp.165-187
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• 2018

The main purpose of this study is to analyze the reform of deadministration of universities in China by the Cooper's 4-dimension of education policy theory. Based on the theory, the reform of deadministration was analyzed in four dimensions(normative, structural, constituent, and technical dimension). First, in the normative dimension, the Chinese university deadministration policy is fully guaranteed by law, and mainly aimed at "modernization of education management system and management ability". Second, in the structural dimension, a highly administrative management paradigm of universities has played an important role during the early stages of higher education development, but it now becomes one of the main obstacle to its further development. However, the Chinese university de-administration policy is a policy that has taken almost 60 years. Therefore, this problem must be solved step by step. Third, in the constituent dimension, although there were some differences in the attitudes towards "the administration" and "the de-administration" of Chinese scholars, university presidents and the public(students), most of them agreed on eliminating "the administration of universities." Fourth, in the technical dimension, Chinese central government and many universities have accumulated many achievements of "the deadministration policies" in management and practice, while some criticisms are heard, either. However, I hope that all reform cases, regardless of their success or failure, will become a model for future administrative reforms.

• Journal of Korea Technology Innovation Society
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• v.22 no.3
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• pp.382-415
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• 2019

This study analyzes the impact of exclusive subcontracting on the input, behavior, and output of innovation in manufacturing industries of Korea. Based on the analysis of pooled cross-sectional data of 6,029 small venture firms, this study proved that the exclusive subcontracting between small venture firms and large enterprises are lowering R&D investment of small venture firms. Second, the innovation activities of small venture firms including the ratio of R&D personnel and the scope of cooperation and partnership with external organizations were lower than those of small venture firms that have non-exclusive or no relations with large enterprises. Third, the innovation performance of small venture firms such as the number of patent applications, the ratio of sales by new products, and the cumulative sales growth rate was lower than those of small venture firms that have non-exclusive or no relations with large enterprises. This study verifies that the exclusive subcontracting relationships significantly weaken the innovation process and performance of small venture firms systematically, resulting in a kind of market failure in which small venture firms have almost no incentive to facilitate innovation.

• The Journal of Engineering Geology
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• v.28 no.4
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• pp.605-618
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• 2018

Korea follows the slope design criteria during construction. It was enacted by the Ministry of Land, Transport and Maritime Affairs. There are cases where the Soil-nail is designed as a measure to secure slope stability. The arrangement of the soil-nail may be arranged at equal intervals or may be arranged differently depending on the soil failure model. The optimum design of the countermeasure method is determined by securing stability of the slope through optimization of dimensions and shape. However, when uniform nails are placed at low elevations in slopes, the standard safety factor is exceeded, which may hinder economic design. It is preferable to arrange the reinforcement of the nails over the entire slope. When the horizontal spacing of the nails was topology optimized according to the slope height, it was possible to minimize the amount of reinforcement while satisfying the standard safety factor. Since the active load is reduced in the section where the slope height is lowered, the safety factor after reinforcement may be excessively increased. Therefore, the phase optimization method is proposed as an economical optimal design method using the reinforcing shape density. In addition, a relational expression was designed to optimize the horizontal spacing by slope height.