• Journal of Korean Society on Water Environment
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• v.37 no.6
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• pp.458-468
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• 2021

In this study, we investigated the variations of dissolved organic matter (DOM) in an agricultural reservoir during the monsoon period (June to October, 2020) with respect to the organic carbon concentration (DOC), molecular weight distribution, and optical properties. The monsoon period was divided into three phases - beginning storm (BS), during storm (DS), and after storm (AS). Our results showed significant differences in the concentrations and characteristics of DOM during the summer monsoon. The DOC concentrations were decreased after the monsoon, probably due to a dilution effect. In contrast, increasing trends were observed in the specific UV absorbance (SUVA), and relative abundances of humic-like fluorescence and larger-sized compounds. These observations implied that the large-sized and humic-like organic components with terrestrial origins strongly affected the reservoir DOM after the summer monsoon. Meanwhile, biopolymer size fraction, which is associated with algal activity, became more abundant after the monsoon. These results suggest that DOM with autochthonous sources became dominant as a result of the inflow of nutrients into the reservoir after the storm. Spatial changes in DOM within the reservoir were not pronounced as much as the temporal variations. All taken, it can be concluded that the summer monsoon simply led to the decrease of DOM concentrations while the sources and the quality of DOM underwent substantial changes, which may enrich refractory organic matter in the reservoir. This study reveals the importance of in-depth DOM quality monitoring before and after summer monsoon for effective water quality management in agricultural reservoirs.

• Korean Journal of Head & Neck Oncology
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• v.38 no.2
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• pp.23-27
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• 2022

Systemic lupus erythematosus(SLE) is a multisystemic disorder of autoimmune etiology. SLE can occur commonly in young women, and the early symptoms include fever, myalgia, arthralgia, weight loss, lymphadenopathy and these nonspecific symptoms develop into skin rash, splenomegaly, serositis and encephalopathy. Diagnosis of SLE requires clinical and serologic criteria, and treatment choices are hydroxyquinolone and NSAIDs for mild disease, corticosteroids and immunosuppressant for severe disease. In lupus patient, the prevalence of lymphadenopathy is 12~59%. Although lymphadenopathy is common finding in SLE, it is hard to distinguish in early phase of SLE. A 38-year-old woman visited our hospital for cervical lymphadenopathy with polyarthritis and malaise. Multiple cervical lymph nodes enlargement was found on Neck CT, and serologic laboratory test including ANA, antiphospholipid antibody, and anti-dsDNA was positive. For excluding lymphoma, PET-CT and excisional biopsy were performed. The patient finally diagnosed with SLE, and got regular follow-up without complication.

• Korean Journal of Veterinary Service
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• v.45 no.2
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• pp.133-137
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• 2022

Lumpy skin disease (LSD) is a severe cross-border infectious disease that causes fever, skin and visceral nodules in cattle. LSD is caused by the lumpy skin disease virus (LSDV), a dsDNA virus that belongs to the genus Capripoxvirus. Although LSD has been found only in Southern Africa traditionally, in the last decade it is spreading very quickly through the Middle East and into Eastern Europe and China. It usually affects cattle and water buffalos being transmitted by blood-feeding insects. As it causes a huge economic impact, LSD is a notifiable disease by World Organisation for Animal Health, and managed as the legal infectious disease class I in Korea. Therefore, the purpose of this study was to confirm the existence of LSDV antigens or antibodies in Korean livestock. We collected 1,200 blood samples from cattle (Korean native and dairy cattle) and Korean water deer in 4 major provinces of the country, then tested the existence of LSDV antigen and antibody. None (0.0%) of the 1,200 blood samples were positive for both antigen and antibody of LSDV. To the best of our knowledge, this is the first study that examines the prevalence of LSDV in Korea. Our study aims to report the LSDV occurrence situation obtained by surveillance in Korea and provide information that may help prevention of LSD epidemics.

• Journal of Ocean Engineering and Technology
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• v.36 no.3
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• pp.181-193
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• 2022

This study presents a mission management technique that is a key component of underwater docking system used to expand the operating range of autonomous underwater vehicle (AUV). We analyzed the docking scenario and AUV operating environment, defining the feasible initial area (FIA) level, event level, and global path (GP) command to improve the rate of docking success and AUV safety. Non-holonomic constraints, mounted sensor characteristic, AUV and mission state, and AUV behavior were considered. Using AUV and docking station, we conducted experiments on land and at sea. The first test was conducted on land to prevent loss and damage of the AUV and verify stability and interconnection with other algorithms; it performed well in normal and abnormal situations. Subsequently, we attempted to dock under the sea and verified its performance; it also worked well in a sea environment. In this study, we presented the mission management technique and showed its performance. We demonstrated AUV docking with this algorithm and verified that the rate of docking success was higher compared to those obtained in other studies.

• Journal of the Korea Society for Simulation
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• v.32 no.3
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• pp.67-74
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• 2023

A semiconductor fabrication facility(FAB) is one of the most capital-intensive and large-scale manufacturing systems which operate under complex and uncertain constraints through hundreds of fabrication steps. To improve fab performance with intuitive scheduling, practitioners have used weighted-sum scheduling. Since the determination of weights in the scheduling significantly affects fab performance, they often rely on simulation-based decision making for obtaining optimal weights. However, a large-scale and high-fidelity simulation generally is time-intensive to evaluate with an exhaustive search. In this study, we investigated three sampling methods (i.e., Optimal latin hypercube sampling(OLHS), Genetic algorithm(GA), and Decision tree based sequential search(DSS)) for the optimization. Our simulation experiments demonstrate that: (1) three methods outperform greedy heuristics in performance metrics; (2) GA and DSS can be promising tools to accelerate the decision-making process.

• Biomolecules & Therapeutics
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• v.30 no.2
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• pp.170-178
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• 2022

The airway epithelium is equipped with the ability to resist respiratory disease development and airway damage, including the migration of airway epithelial cells and the activation of TLR3, which recognizes double-stranded (ds) RNA. Primary cilia on airway epithelial cells are involved in the cell cycle and cell differentiation and repair. In this study, we used Beas-2B human bronchial epithelial cells to investigate the effects of the TLR3 agonist polyinosinic:polycytidylic acid [Poly(I:C)] on airway cell migration and primary cilia (PC) formation. PC formation increased in cells incubated under serum deprivation. Migration was faster in Beas-2B cells pretreated with Poly(I:C) than in control cells, as judged by a wound healing assay, single-cell path tracking, and a Transwell migration assay. No changes in cell migration were observed when the cells were incubated in conditioned medium from Poly(I:C)-treated cells. PC formation was enhanced by Poly(I:C) treatment, but was reduced when the cells were exposed to the ciliogenesis inhibitor ciliobrevin A (CilioA). The inhibition of Beas-2B cell migration by CilioA was also assessed and a slight decrease in ciliogenesis was detected in SARS-CoV-2 spike protein (SP)-treated Beas-2B cells overexpressing ACE2 compared to control cells. Cell migration was decreased by SP but restored by Poly(I:C) treatment. Taken together, our results demonstrate that impaired migration by SP-treated cells can be attenuated by Poly(I:C) treatment, thus increasing airway cell migration through the regulation of ciliogenesis.

• Nuclear Engineering and Technology
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• v.55 no.4
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• pp.1563-1570
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• 2023

In this study, a DeCART/MIG uncertainty quantification (UQ) analysis code system with a multicorrelated cross section stochastic sampling (S.S.) module was established and verified through the UAM (Uncertainty Analysis in Modeling) and the BEAVRS (Benchmark for Evaluation And Validation of Reactor Simulations) benchmark calculations. For the S.S. calculations, a sample of 500 DeCART multigroup cross section sets for two major actinides, i.e., ²³⁵U and ²³⁸U, were generated by the MIG code and covariance data from the ENDF/B-VII.1 evaluated nuclear data library. In the three pin problems (i.e. TMI-1, PB2, and Koz-6) from the UAM benchmark, the uncertainties in k_inf by the DeCART/MIG S.S. calculations agreed very well with the sensitivity and uncertainty (S/U) perturbation results by DeCART/MUSAD and the S/U direct subtraction (S/U-DS) results by the DeCART/MIG. From these results, it was concluded that the multi-group cross section sampling module of the MIG code works correctly and accurately. In the BEAVRS whole benchmark problems, the uncertainties in the control rod bank worth, isothermal temperature coefficient, power distribution, and critical boron concentration due to cross section uncertainties were calculated by the DeCART/MIG code system. Overall, the uncertainties in these design parameters were less than the general design review criteria of a typical pressurized water reactor start-up case. This newly-developed DeCART/MIG UQ analysis code system by the S.S. method can be widely utilized as uncertainty analysis and margin estimation tools for developing and designing new advanced nuclear reactors.

• Bulletin of the Korean Mathematical Society
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• v.60 no.4
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• pp.1085-1100
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• 2023

For any given function f, we focus on the so-called prescribed mean curvature problem for the measure e^-f(|x|2)dx provided thate^-f(|x|2) ∈ L¹(ℝⁿ⁺¹). More precisely, we prove that there exists a smooth hypersurface M whose metric is ds² = dρ² + ρ²d𝜉² and whose mean curvature function is ${\frac{1}{n}}(\frac{u^p}{{\rho}^{\beta}})e^{f({\rho}^2)}{\psi}(\xi)$ for any given real constants p, β and functions f and ψ where u and ρ are the support function and radial function of M, respectively. Equivalently, we get the existence of a smooth solution to the following quasilinear equation on the unit sphere 𝕊ⁿ, $${\sum_{i,j}}({{\delta}_{ij}-{\frac{{\rho}_i{\rho}_j}{{\rho}^2+|{\nabla}{\rho}|^2}})(-{\rho}ji+{\frac{2}{{\rho}}}{\rho}j{\rho}i+{\rho}{\delta}_{ji})={\psi}{\frac{{\rho}^{2p+2-n-{\beta}}e^{f({\rho}^2)}}{({\rho}^2+|{\nabla}{\rho}|^2)^{\frac{p}{2}}}}$$ under some conditions. Our proof is based on the powerful method of continuity. In particular, if we take $f(t)={\frac{t}{2}}$, this may be prescribed mean curvature problem in Gauss measure space and it can be seen as an embedded result in Gauss measure space which will be needed in our forthcoming papers on the differential geometric analysis in Gauss measure space, such as Gauss-Bonnet-Chern theorem and its application on positive mass theorem and the Steiner-Weyl type formula, the Plateau problem and so on.

• 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.

• Korean Journal of Exercise Nutrition
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• v.23 no.4
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• pp.6-13
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• 2019

[Purpose] In this study, we examined the in vitro antioxidant activities and laxative effects of taurine-xylose (T-X), a synthetic taurine-carbohydrate derivative, in a rat model of constipation induced by loperamide. [Methods] The animals were divided into four treatment groups: normal untreated rats (NOR group), loperamide-treated control rats (CON group), loperamide and taurine-xylose (15 mg/kg)-treated rats (T-X group), and loperamide and commercial Dulcolax S (5.5 mg/kg)-treated rats (DS group). [Results] In the present study, T-X exhibited potent reducing power and free radical scavenging activities for DPPH (1,1-diphenyl-2-picrylhydrazyl) and ABTS+ (2,2'-azino-bis (3-ethylbenzothiazoline 6-sulfonic acid ammonium salt) radicals. The laxative effects of T-X were dependent on food, body weight, fecal properties, gastrointestinal transit (GIT) ratio, and serum metabolic parameters. In the T-X group, the number, wet weight, and water content of fecal pellets were noticeably increased compared to those in the loperamide-induced group. T-X treatment significantly increased the activities of hepatic antioxidant enzymes, including those of glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), and catalase (CAT), relative to those in loperamide-induced constipated rats. Furthermore, the GIT ratio and loperamide-induced metabolic parameters in serum, including gastrin (GAS), motilin (MTL), and somatostatin (SS) levels, were significantly improved by T-X treatment. [Conclusion] These results suggest that taurine-xylose exerts antioxidant activities and laxative effects on loperamide-induced constipation by promoting gastrointestinal motility.