• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.9 no.5
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• pp.496-502
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• 2016

In this study, we investigated the comparative NHPP software model based on learning techniques that operators in the process of software testing and development of software products that can be applied to software test tool. The life distribution was applied Makeham distribution based on finite fault NHPP. Software error detection techniques known in advance, but influencing factors for considering the errors found automatically and learning factors, by prior experience, to find precisely the error factor setting up the testing manager are presented comparing the problem. As a result, the learning factor is larger than automatic error that is usually well-organized model could be established. This paper, a trust characterization of applying using time among failures and parameter approximation using maximum likelihood estimation, after the effectiveness of the data through trend examination model selection were well-organized using the mean square error and $R^2$. From this paper, the software operators must be considered life distribution by the basic knowledge of the software to confirm failure modes which may be helped.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.4
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• pp.449-456
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• 2007

Dispersion coefficient preprocessing schemes have been examined to improve plume dispersion model performance in complex coastal areas. The performances of various schemes for constructing the sigma correction order were evaluated through estimations of statistical measures, such as bias, gross error, R, FB, NMSE, within FAC2, MG, VG, IOA, UAPC and MRE. This was undertaken for the results of dispersion modeling, which applied each scheme. Environmental factors such as sampling time, surface roughness, plume rising, plume height and terrain rolling were considered in this study. Gaussian plume dispersion model was used to calculate 1 hr $SO_2$ concentration 4 km downwind from a power plant in Boryeung coastal area. Here, measured data for January to December of 2002 were obtained so that modelling results could be compared. To compare the performances between various schemes, integrated scores of statistical measures were obtained by giving weights for each measure and then summing each score. This was done because each statistical measure has its own function and criteria; as a result, no measure can be taken as a sole index indicative of the performance level for each modeling scheme. The best preprocessing scheme was discerned using the step-wise method. The most significant factor influencing the magnitude of real dispersion coefficients appeared to be sampling time. A second significant factor appeared to be surface roughness, with the rolling terrain being the least significant for elevated sources in a gently rolling terrain. The best sequence of correcting the sigma from P-G scheme was found to be the combination of (1) sampling time, (2) surface roughness, (3) plume rising, (4) plume height, and (5) terrain rolling.

• Journal of Energy Engineering
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• v.6 no.2
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• pp.203-211
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• 1997

This study is on the separation of Global warming effect gas, CO$_2$by chemical absorption from mixture of CO$_2$-N$_2$which was modeled after flue gas of fire power plant. Investigation of optimum condition for absorbent was carried out by using sparged vessel apparatus. Through packed tower experiments, applicabilities of two absorption models were tested by comparing experimental results with theoretical values. Absorbent used in the experiments was Monoethanolamine (MEA) and gas mixture was made in the mole composition of 15% CO$_2$and 85% N$_2$. Through estimations of CO$_2$loading and CO$_2$removal efficiency, optimum concentration of absorbent was found in the range of 4-5 M. To find a rate of absorption, an enhancement factor was introduced. Values of rate of absorption were calculated by Film model and Higbie model, respectively. Higbie model showed good agreement with experimental results. Therefore, this models is considered to be applicable to the CO$_2$separation process for flue gas from fire power plant.

• Journal of Internet Computing and Services
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• v.10 no.1
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• pp.135-143
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• 2009

The purpose of this study was to explore factors that affected the satisfaction of students' experiences in an education course, with the educational method and educational technology designed with a blended learning strategy. Blended learning is currently recognized as a good solution for the problems posed by both online and face-to-face learning, because it has features like flexibility and accessibility by using tools supporting both individualization and socialization. This study is one case that illustrates how blended learning can be applied at the university level. Subjects were 56 students who had participated in the class and responded to the survey questions. The gathered data were analyzed by using Factor Analysis and the Structural Equation Model. Based on the results of Factor Analysis, data revealed 5 factors: learning motivation, previous experience, ability to use information & technology, capability of self-regulated learning, and learning satisfaction. The results of the Structural Equation Model revealed causal relationships among the aforementioned factors as follows: (a) there was a statistically meaningful causal relationship between "learning motivation" and "capability of self-regulated learning", (b) there was a statistically meaningful casual relationship between "previous experience" and "capability of self-regulated learning", and (c) "capability of self-regulated learning" directly affected "learning satisfaction".

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.1
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• pp.7-13
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• 2011

The behavior prediction of PAHs in Jinhae Bay using a three-dimensional ecological model(EMT-3D) was examined. A three-dimensional ecological model(EMT-3D) was applied to the simulation of PAHs behaviors in Jinhae Bay of Korea. The computed results of simulation were in good agreement with the observed values. The result of sensitivity analysis showed that photolysis coefficient and extinction coefficient were important factors in the variation of dissolved PAHs, and POC partition coefficient was important factor in the variation of PAHs in particulate organic matter. In the case of PAHs in phytoplankton, bioconcentration factor of plankton was the most significant and the most effective in all. In simulations of 30%, 50% and 80% reduction in total loads of PAHs, the concentrations of dissolved PAHs were shown to be lower than 24 ng/L, 20 ng/L and 16 ng/L, respectively.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.7
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• pp.3009-3014
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• 2015

The epidermal growth factor (EGF) may play a pathological role in hepatocellular carcinoma (HCC). However, the conclusions of published reports on the relationship between the EGF $61^*A/G$ polymorphism and HCC risk remain controversial. To derive a more precise estimation we performed a meta-analysis based on 14 studies that together included 2,506 cases and 4,386 controls. PubMed, EMBASE, Web of Knowledge and the Chinese National Knowledge Infrastructure (CNKI) databases were used to retrieve articles up to August 1, 2014. The crude odds ratios (ORs) with 95% confidence intervals (95%CIs) were calculated to evaluate the association. Meta-analysis results showed a significant association between the EGF $61^*A/G$ polymorphism and HCC risk in all four genetic models (allele model: OR=1.25, 95%CI=1.12-1.40; dominant model: OR=1.32, 95%CI=1.14-1.54; recessive model: OR=1.33, 95%CI=1.12-1.58; ho-mozygous model: OR=1.59, 95%CI=1.33-1.90). Moreover, significant associations were observed when stratified by ethnicity, source of controls, etiology and genotype methods. Thus, this meta-analysis suggests that the G-allele of the EGF $61^*A/G$ polymorphism is associated with an increased risk of HCC, especially in Asians and Caucasians, without influence from the source of controls or etiological diversity. Further studies with larger population sizes are needed to confirm these results.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.1
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• pp.1-12
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• 2013

Purpose: Vascular endothelial growth factor (VEGF)-C and its tyrosine kinase receptor, VEGF receptor (VEGFR)-3 are recently known to have lymphangiogenic activities in various tumor types. In this study, we determined whether the expression of lymphangiogenic factors correlate with nodal metastasis or survival in a nude mouse model of oral squamous cell carcinoma (OSCC). Methods: Three OSCC cells (KB, SCC4, SCC9) were xenografted into the right mandibular gland of athymic nude mice. The mice were followed for tumor development and growth, and the mice were sacrificed when they had lost more than 20% of their initial body weight, or the diameter of the induced tumor exceeds 20 mm. After necropsy, the murine tumors were examined histologically and radiologically (micro-positron emission tomography computed tomography) for regional or distant metastasis. We performed immunohistochemical assays with anti-VEGF-C, VEGFR-3, CD105, and D2-40 antibodies. Immunofluorescence double staining for LYVE-1/CD31 was also performed. To quantify the VEGF-C and VEGFR-3 level in the cancer tissue, Western blotting was performed. Finally, we determined the correlation between the degree of expression of VEGF-C/VEGFR-3 and the mean survival time. Results: OSCC tumor cells into the mandibular gland of the nude mice successfully resulted in the formation of recapitulating orthotopic tumor. Tumor cells of the induced tumor did not express VEGF-C. VEGF-C/VEGFR-3 expression was mainly distributed in the endothelial cells of the stromal area. There were no correlation between the degree of expression of VEGF-C/VEGFR-3 and the mean survival time of mice injected with different OSCC cell lines. Conclusion: An recapitulating orthotopic model of OSCC in nude mice was established, which copies the cervical nodal metastasis of human OSCC. Overexpression of lymphangiogenic factors seems to have no effect on survival of hosts in this in vivo experiment.

• Convergence Security Journal
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• v.11 no.6
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• pp.73-80
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• 2011

In this study, software products developed in the course of testing, software managers in the process of testing software and tools for effective learning effects perspective has been studied using the NHPP software. The delayed software S-shaped reliability model applied to distribution was based on finite failure NHPP. Software error detection techniques known in advance, but influencing factors for considering the errors found automatically and learning factors, by prior experience, to find precisely the error factor setting up the testing manager are presented comparing the problem. As a result, the learning factor is greater than automatic error that is generally efficient model could be confirmed. This paper, numerical example of applying using time between failures and parameter estimation using maximum likelihood estimation method, after the efficiency of the data through trend analysis model selection were efficient using the mean square error and $R^2$(coefficient of determination).

• Journal of the Korean earth science society
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• v.34 no.1
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• pp.51-58
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• 2013

An appropriate determination of time step is one of the important problems in atmospheric modeling. In this study, we investigate the sensitivity of numerical solutions to time step in a nonlinear atmospheric model. For this purpose, a simple nondimensional dynamical model is employed, and numerical experiments are performed with various time steps and nonlinearity factors. Results show that numerical solutions are not sensitive to time step when the nonlinearity factor is not influentially large and truncation error is negligible. On the other hand, when the nonlinearity factor is large (i.e., in a highly nonlinear regime), numerical solutions are found to be sensitive to time step. In this situation, smaller time step increases the intensity of the spatial filter, which makes small-scale phenomena weaken. This conflicts with the fact that smaller time step generally results in more accurate numerical solutions owing to reduced truncation error. This conflict is inevitable because the spatial filter is necessary to stabilize the numerical solutions of the nonlinear model.

• Korean Journal of Organic Agriculture
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• v.27 no.3
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• pp.271-288
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• 2019

It has continuously promoted to scale up the agricultural management body in order to cope with the market-opening pressure such as the UR negotiation, the DDA negotiation, and more conclusions of FTAs and to enhance the competitiveness of our agriculture. This study evaluated the factors associated with production organization participation centered on environmentally-friendly agriculture farmers in order to improve the production efficiency of environmentally-friendly agriculture in the aspect of production. In order to achieve this objective, this study evaluated the factors that contributed to participating in an organization using the bivariate probit model focusing on environmentally-friendly agriculture farmers in Chungnam. This study examined the validity and reliability of the study model through exploratory factor analysis. The results of factor analyses identified four factors: "distribution", "production", "organization operation", and "social capital". The results of the bivariate probit model showed that distribution significantly affected production activities and distribution, organization operation, agricultural income, and gender significantly influenced sale activities. Environmentally-friendly production organization had not been able to provide the productive support that was needed for local farmers to produce environmentally-friendly agricultural products in a region. Additionally, farming education did not provide the information needed by the farmers. Although producers had a network within a production organization, it was operated mainly for administrators. Therefore, participants felt somewhat lacking. This study identified the level of organization of producer organizations in Chungnam area, where environmentally-friendly agriculture is well activated. This study suggested implications for future production organization participation by evaluating factors affecting participation quantitatively.