• Journal of Korea Technology Innovation Society
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• v.14 no.3
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• pp.578-598
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• 2011

This study estimates the value of photovoltaic core material technology, which is getting attention as a clean energy source. The estimation is based on the real option pricing model (ROPM). This study has two main contributions. The first is in the methodology. The process of modeling volatility, which is the most complicated stage in ROPM, is greatly simplified by using the stock price as a covariate representing the volatility of the real option's basic asset. The second contribution is the application of technology. In this study, the economic value of poly-silicon, a core material in the photovoltaic industry and recently surging in demand, is evaluated as a manufacturing technology. In a case study of a company in the photovoltaic industry, the stochastic process of a basic asset follows geometric Brownian motion (GBM), and the option value of firm A's poly-silicon manufacturing technology is estimated at 3.4 trillion won.

• Tunnel and Underground Space
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• v.26 no.3
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• pp.235-252
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• 2016

This study presents a methodology to reproduce the mechanical behavior of isotropic or transversely isotropic rock using the polygonal grain-based distinct element model. A numerical technique to monitor the evolution of micro-cracks during the simulation was developed in the present study, which enabled us to examine the contribution of tensile cracking and shear cracking to the progressive process of the failure. The numerical results demonstrated good agreement with general observations from rock specimens in terms of the behavior and the evolution of micro-cracks, suggesting the capability of the model to represent the mechanical behavior of rock. We also carried out a parametric study as a fundamental work to examine the relationships between the microscopic properties of the constituents and the macroscopic behavior of the model. Depending on the micro-properties, the model exhibited a variety of responses to the external load in terms of the strength and deformation characteristics. In addition, a numerical technique to reproduce the transversely isotropic rock was suggested and applied to Asan gneiss from Korea. The behavior of the numerical model was in good agreement with the results obtained in the laboratory-scale experiments of the rock.

• The Journal of Korean Medicine
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• v.30 no.2
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• pp.63-78
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• 2009

Objective: The purpose of experimental study was to prove the effects of Boyangmakseong-bang (BYMSB) treatment on cBSA-induced in a MN mouse model. Methods: We divided mice into 4 groups. The Normal group had no treatment. We used cBSA and induced MN mouse model to the other 3 groups. The Control group was treated with cBSA (9mg/kg i.p) only. The second group, named 'BY-250', was treated with cBSA (9mg/kg i.p) and BYMSB extract (250mg/kg, p.o). The third group, named 'BY-500', was treated with cBSA (9mg/kg i.p) and BYMSB extract (500mg/kg, p.o). After cBSA and BYMSB extract treatment for 4 weeks, the increase in percentage of body weight, proteinuria, serum albumin, total cholesterol, creatinine and BUN of all groups were measured. The CD3+, CD19+, CD4+, CD8+ cell levels of spleen of all groups were analyzed. IgA, IgG, IgM, IL-$1{\beta}$, TNF-${\alpha}$, IL-6 and IFN-${\gamma}$ levels of all groups were gauged. H&E staining, immunofluorescence staining and electron microscopy of kidney were observed. Results: BYMSB showed significant decrease in the 24hrs proteinuria, serum total cholesterol, serum IgG levels and BUN levels, and showed significant increase in the serum albumin levels compared with the control group. BYMSB showed increase in the increasing percentage of body weight and IFN-${\gamma}$ levels compared with the control. BYMSB showed decrease in the CD3+ T cells, CD4+ Th cells, IL-$1{\beta}$, TNF-${\alpha}$ and IL-6 levels, but did not show significant change compared with the control. BYMSB showed considerable decrease in the thickening of the GBM on H&E staining, deposition of IgG on immunofluorescence staining and deposition of electron-density on electron microscopy of kidney compared with the control. Conclusions: According to the above results, it is suggested that BYMSB decreases the symptoms of MN induced by cBSA in a mouse model. Therefore BYMSB seems to be applicable to MN in clinical practice.

• The Journal of Internal Korean Medicine
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• v.30 no.3
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• pp.495-509
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• 2009

Objective : Membranous nephropathy(MN) is an organ-specific autoimmune disease and a relatively common cause of nephrotic syndrome in adults worldwide. But treatment of MN is not defined. This study was to evaluate the effects of Acasia Catechu extract(ACE) on the MN induced by cBSA in mice. Methods : Mice were divided into 4 groups. The normal group was injected with a saline solution. The control group was treated with cBSA(10 mg/kg i.p.) only. The third group was treated with cBSA (10 mg/kg i.p.) and ACE (250 mg/kg, p.o.). The fourth group was treated with cBSA (10mg/kg i.p.) and ACE (500mg/kg, p.o.). After cBSA and ACE treatment for 6 weeks, we measured change of body weight, 24hrs proteinuria, serum albumin, total cholesterol, triglyceride, BUN, creatinine, TNF-$\alpha$, IL-6, IL-$1{\beta}$, IFN-$\gamma$, IgA, IgM and IgG levels. The morphologic changes of renal glomeruli were also observed with a light microscope. Results : The levels of 24 hrs proteinuria, total cholesterol, triglyceride, IgG, IgM, IgA, TNF-$\alpha$, IL-6, IL-$1{\beta}$, IFN-$\gamma$ significantly decreased in both ACE groups. The level of albumin significantly increased in both ACE groups. The mRNA expression of IL-$1{\beta}$ in splenocytes considerably decreased in the ACE-500 group. In histological findings of kidney tissue, thickening of GBM decreased in both ACE groups. Conclusions : This study shows that ACE might be effective for treatment of MN. More clinical data and studies are to be done for efficient application.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.6 no.1
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• pp.10-19
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• 2020

Boron Neutron Capture Therapy (BNCT) has the advantage of selectively removing cancer cells ingesting boron compounds. In this study, the benefits for treatment time and boron compound injection dose were compared between current neutron sources and a high current neutron sources to be developed in near future. The time-activity curve (TAC) of GBM (Glioblastoma) for one bolus injection was obtained by applying modified 3 compartment model. The treatment time was determined for an accelerator-based neutron sources at the present time and a high current accelerator based neutron source to be developed in the near future. In the case of the double amount of IAEA-recommended neutron flux, the treatment time was shortened to 15 minutes. In the case of high current accelerators, which are five times the amount of IAEA-recommended neutron flux, the irradiation time is within 5 minutes. The use of a high current accelerator based neutron source in BNCT is advantageous in terms of treatment time. In addition, it can increase the efficiency of use of neutrons and reduce the boron compound injection dose to patients, thus reducing pharmacological toxicity.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.5
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• pp.1063-1072
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• 2009

Membranous nephropathy(MN) is the most common cause of adult nephrotic syndrome worldwide. But treatment of MN is not defined. This study was to evaluate the effects of Lonicerae Flos Extract(LFE) on the MN induced by cBSA in mice. Mice were divided into 4 groups. The first group named for 'Normal' was injected with a saline solution. The second group named 'Control' treated with cBSA(10 mg/kg i.p) only. The third group named 'LFE-250', treated with cBSA(10 mg/kg i.p) and LFE(250 mg/kg, p.o). The fourth group named 'LFE-500'treated with cBSA(10 mg/kg i.p) and LFE(500 mg/kg, p.o). After cBSA and LFE treatment for 4 weeks, we measured change of body weight, 24hrs proteinuria, serum albumin, total cholesterol, triglyceride, BUN, creatinine, TNF-$\alpha$, IL-6, IL-$1{\beta}$, IL-10, IFN-$\gamma$, IgA, IgM and IgG levels. The morphologic changes of renal glomeruli were also observed with a light microscope. The levels of 24 hrs proteinuria, total cholesterol, IgG , IgM, IgA, IL-6 were significantly decreased in both LFE groups. The level of triglyceride, IL-$1{\beta}$ was significantly decreased in LFE-500 group. The level of Albumin was significantly increased in LFE-250 group. The level of TNF-$\alpha$, IFN-$\gamma$ were significantly decreased in LFE-250 group. The mRNA expression of IL-$1{\beta}$ in splenocytes was consideraly decreased in LFE-500 group. In histological findings of kidney tissue, thickening of GBM decreased in both LFE groups. This study shows that the LFE might be effective for treatment of MN. More clinical data and studies are to be done for efficient application.

• The Journal of Korean Medicine
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• v.30 no.4
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• pp.93-107
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• 2009

Objective: Membranous nephropathy (MN) is one of the most common causes of nephrotic syndrome in adults. However, there is not a satisfactory treatment for MN. This study aimed to evaluate the effect of Houttuyniae Herba Extract (HHE) on MN induced by cationic bovine serum albumin (cBSA). Methods: Mice were divided into 4 groups. The first group, Normal, was injected with saline. The second group, Control, was treated with cBSA (10mg/kg i.p) only. The third group, HHE-250, was treated with cBSA (10mg/kg i.p) and HHE (250mg/kg, p.o). The fourth group, HHE-500, was treated with cBSA (10mg/kg i.p) and HHE (500mg/kg, p.o). After treatment for 4 weeks, we measured change of body weight, 24 hrs proteinuria, serum albumin, total cholesterol, triglyceride, BUN, creatinine, IgA, IgM, IgG, TNF-${\alpha}$, IL-1${\beta}$ levels and the mRNA expression of IFN-${\gamma}$, IL-6, and IL-10. The morphologic changes of renal glomeruli were also observed with a light microscope and an electron microscope. Results: The levels of 24 hrs proteinuria and serum triglyceride, BUN, IgG, TNF-${\alpha}$, IL-1${\beta}$ significantly decreased in both HHE groups, while the level of serum albumin significantly increased in both HHE groups. The mRNA expression of IFN-${\gamma}$ and IL-6 in splenocytes considerably increased in both HHE groups. The mRNA expression of IL-10 in splenocytes considerably decreased in both HHE groups. In histological findings of kidney tissue, thickening of GBM decreased in both HHE groups. Conclusions: This study shows that HHE might be effective for treatment of acute stage MN. More clinical data and studies are to be done for efficient application.

• Biomolecules & Therapeutics
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• v.2 no.4
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• pp.376-382
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• 1994

Repeated injections of low-doses of mercuric chloride in rats or mice induce polyclonal activation which includes the induction of anti-glomerular basement membrane (GBM) antibodies and circulating immune complex and it results in nephritis. Because this disease is autoimmune mediated disease resulted from immune dysfunction, immunomodulators are used to control the symptoms or to cure the disease. Irpex lacteus Fr. is a kind of new medicinal fungus. The polysaccharide fraction extracted from submerged fermentation of Irpex lacteus Fr. decreased the serum agglutinin, serolysin and IgM plaque forming cells in normal mice. The hitherto obtained clinical results suggested that it significantly improved the oligourea, edema, and hypertension in patients who have nephritis. To elucidate the action-mechanisms of Irpex lacteus Fr., we established the experimental model of HgCl$_2$induced polyclonal activation by intraperitoneal administrations of HgCl$_2$to mice. To assess the immunomodulating effect of Irpex lacteus fraction, we Investigated its effects on the mitogen induced proliferation and IgM PFC counts of splenic lymphocytes in mice during the treatment of HgCl$_2$. The Irpex lacteus polysaccharide reduced the abnormally increased mitogen induced Iymphocyte proliferation and IgM PFCs to almost normal levels. And the Irpex lacteus polysaccharides prevented the increasement of serum immunoglobulin level induced by HgCl$_2$. These data suggested that the Irpex lacteus polysaccharides might have the immunomodulating activity to prevent and /or improve the HgCl$_2$ induced autoimmune disease.

• Journal of the Korea Society of Computer and Information
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• v.28 no.8
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• pp.49-58
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• 2023

Dropouts of students not only cause financial loss to the university, but also have negative impacts on individual students and society together. To resolve this issue, various studies have been conducted to predict student dropout using machine learning. This paper presents a model implemented using DNN (Deep Neural Network) and LGBM (Light Gradient Boosting Machine) to predict dropout of university students and compares their performance. The academic record and grade data collected from 20,050 students at A University, a small and medium-sized 4-year university in Seoul, were used for learning. Among the 140 attributes of the collected data, only the attributes with a correlation coefficient of 0.1 or higher with the attribute indicating dropout were extracted and used for learning. As learning algorithms, DNN (Deep Neural Network) and LightGBM (Light Gradient Boosting Machine) were used. Our experimental results showed that the F1-scores of DNN and LGBM were 0.798 and 0.826, respectively, indicating that LGBM provided 2.5% better prediction performance than DNN.

• Journal of Korean Society for Quality Management
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• v.51 no.2
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• pp.171-184
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• 2023

Purpose: First, this paper suggests an alternative approach to find optimal portfolio (stocks, bonds and ESG stocks) under the maximizing utility of investors. Second, we include ESG stocks in our optimal portfolio, and compare improvement of welfares in the case with and without ESG stocks in portfolio. Methods: Our main method of analysis follows Brennan et al(2002), designed under the continuous time framework. We assume that the dynamics of stock price follow the Geometric Brownian Motion (GBM) while the short rate have the Vasicek model. For the utility function of investors, we use the Power Utility Function, which commonly used in financial studies. The optimal portfolio and welfares are derived in the partial equilibrium. The parameters are estimated by using Kalman filter and ordinary least square method. Results: During the overall analysis period, the portfolio including ESG, did not show clear welfare improvement. In 2017, it has slightly exceeded this benchmark 1, showing the possibility of improvement, but the ESG stocks we selected have not strongly shown statistically significant welfare improvement results. This paper showed that the factors affecting optimal asset allocation and welfare improvement were different each other. We also found that the proportion of optimal asset allocation was affected by factors such as asset return, volatility, and inverse correlation between stocks and bonds, similar to traditional financial theory. Conclusion: The portfolio with ESG investment did not show significant results in welfare improvement is due to that 1) the KRX ESG Leaders 150 selected in our study is an index based on ESG integrated scores, which are designed to affect stability rather than profitability. And 2) Korea has a short history of ESG investment. During the limited analysis period, the performance of stock-related assets was inferior to bond assets at the time of the interest rate drop.