• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.6
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• pp.565-572
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• 2009

This work intends to establish the reliability and fracture toughness $K_{IC}$ criterion of welded joints by EGW for high strength EH36-TMCP ultra thick plate. For this, firstly thermo elasto-plastic analysis has been carried out on two pass X-groove butt joint model to clarify the thermal and mechanical behaviour(residual stress, plastic strain, magnitude of stress and their distribution and production mechanism). Moreover, to establish fracture criterion, analysis of fracture toughness $K_{IC}$ has been performed under the notch machined and residual stress with the load condition on EGW welded joints. A quantitative fracture criterion for EGW welded joints is suggested by using $K_{IC}$.

• Journal of The Korean Society of Agricultural Engineers
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• v.62 no.6
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• pp.11-20
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• 2020

We estimated the spatio-temporally distributed soil moisture using Sentinel-1A/B SAR (Synthetic Aperture Radar) sensor images and soil moisture data assimilation technique in South Korea. Soil moisture data assimilation technique can extract the hydraulic parameters of soils using observed soil moisture and GA (Genetic Algorithm). The SWAP (Soil Water Atmosphere Plant) model associated with a soil moisture assimilation technique simulates the soil moisture using the soil hydraulic parameters and meteorological data as input data. The soil moisture based on Sentinel-1A/B was validated and evaluated using the pearson correlation and RMSE (Root Mean Square Error) analysis between estimated soil moisture and TDR soil moisture. The soil moisture data assimilation technique derived the soil hydraulic parameters using Sentinel-1A/B based soil moisture images, ASOS (Automated Synoptic Observing System) weather data and TRMM (Tropical Rainfall Measuring Mission)/GPM (Global Precipitation Measurement) rainfall data. The derived soil hydrological parameters as the input data to SWAP were used to simulate the daily soil moisture values at the spatial domain from 2001 to 2018 using the TRMM/GPM satellite rainfall data. Overall, the simulated soil moisture estimates matched well with the TDR measurements and Sentinel-1A/B based soil moisture under various land surface conditions (bare soil, crop, forest, and urban).

• Journal of Welding and Joining
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• v.27 no.6
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• pp.31-35
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• 2009

When conducting CTOD test, especially in thick welded steel plate, fatigue pre-cracking occasionally failed to satisfy the requirements of standards thus making the test result invalid. Internally accumulated residual stress of test piece has been thought as one of the main reasons. The propagation of fatigue crack, started from the tip of machined notch, which might have propagated irregularly due to residual stress field. To overcome this kind of difficulty three methods to modify the residual stress are suggested in standard i.e. local compression, reverse bending and stepwise high-R ratio method. In this paper not only multi pass welding but also local pre-compressing process of thick steel plate has been simulated using finite element method for clarifying variation of internal welding residual stress. The simulated results show that welding residual stress is compressive in the middle section of the model and it is predominantly increased after machining the specimen. Comparing as-welded state all component of the welding residual stress changing to compressive in the tip of machine notch whereas residual stress of the outer area remain as tensile condition relatively. Analysis results also show that this irregular residual stress distribution is improved to be more uniformly by applying local compression.

• Journal of Ginseng Research
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• v.46 no.3
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• pp.435-443
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• 2022

Background: Post-traumatic stress disorder (PTSD) is a psychiatric disease that develops following exposure to a traumatic event and is a stress-associated mental disorder characterized by an imbalance of neuroinflammation. Korean Red Ginseng (KRG) is the herbal supplement that is known to be involved in a variety of pharmacological activities. We aimed to investigate the effects of KRG on neuroinflammation as a potential mechanism involved in single prolonged stress (SPS) that negatively influences memory formation and consolidation and leads to cognitive and spatial impairment by regulating BDNF signaling, synaptic proteins, and the activation of NF-κB. Methods: We analyzed the cognitive and spatial memory, and inflammatory cytokine levels during the SPS procedure. SPS model rats were injected intraperitoneally with 20, 50, or 100 mg/kg/day KRG for 14 days. Results: KRG administration significantly attenuated the cognitive and spatial memory deficits, as well as the inflammatory reaction in the hippocampus associated with activation of NF-κB in the hippocampus induced by SPS. Moreover, the effects of KRG were equivalent to those exerted by paroxetine. In addition, KRG improved the expression of BDNF mRNA and the synaptic protein PSD-95 in the hippocampus. Taken together, these findings demonstrate that KRG exerts memory-improving actions by regulating anti-inflammatory activities and the NF-κB and neurotrophic pathway. Conclusion: Our findings suggest that KRG is a potential functional ingredient for protecting against memory deficits in mental diseases, such as PTSD.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3409-3416
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• 2023

Licensing the next-generation of nuclear reactor designs requires extensive use of Modeling and Simulation (M&S) to investigate system response to many operational conditions, identify possible accidental scenarios and predict their evolution to undesirable consequences that are to be prevented or mitigated via the deployment of adequate safety barriers. Deep Learning (DL) and Artificial Intelligence (AI) can support M&S computationally by providing surrogates of the complex multi-physics high-fidelity models used for design. However, DL and AI are, generally, low-fidelity 'black-box' models that do not assure any structure based on physical laws and constraints, and may, thus, lack interpretability and accuracy of the results. This poses limitations on their credibility and doubts about their adoption for the safety assessment and licensing of novel reactor designs. In this regard, Physics Informed Neural Networks (PINNs) are receiving growing attention for their ability to integrate fundamental physics laws and domain knowledge in the neural networks, thus assuring credible generalization capabilities and credible predictions. This paper presents the use of PINNs as surrogate models for accidental scenarios simulation in Nuclear Power Plants (NPPs). A case study of a Loss of Heat Sink (LOHS) accidental scenario in a Nuclear Battery (NB), a unique class of transportable, plug-and-play microreactors, is considered. A PINN is developed and compared with a Deep Neural Network (DNN). The results show the advantages of PINNs in providing accurate solutions, avoiding overfitting, underfitting and intrinsically ensuring physics-consistent results.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.1
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• pp.99-107
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• 2001

Manufacture of fishing vessel is needed the effective material for light, strength, fire and corrosion of water in order to improve durability by high-speed and fishing. These fishing vessel can be divided into FRP and AI alloys fishing vessel. FRP fishing vessel is light and effective for strength but highly ignited and susceptible to heat during the manufacturing ship by-produce noxious component for human. In the case of a scrapped ship, it cause environmental pollution. On the other hand, aluminum is a material in return for FRP and has merit of high-strength and lightness. It's more heat proof and durable than FRP and superior to prevent from corrosion. Al alloys fishing vessel development is rising as an urgent matter. But, al alloy has some defect of bad weldability, welding transformation, cracks and overcost of construction. Therefore this study is to develop the new welding joint shape solving aluminum defects and mechanical behavior. First of all, strength was compared and reviewed by analysis of plate, stiffen plate, new model simplified by using plate theory. On the base of this result, plate and new model of temperature distribution, weld residual stress and strength of tensile, compressive force were compared and reviewed by finite element computer program has been developed to deal with heat conduction and thermal elasto plastic problem. Also, new model is proved application possibility and excellent mechanic by strength comparison is established to tensile testing result.

• Journal of Korean Theatre Studies Association
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• no.40
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• pp.239-275
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• 2010

Cette ${\acute{e}}tude$ a pour but de proposer une $m{\acute{e}}thodologie$ de critique avec la $s{\acute{e}}miotique$ ouverte. La critique de $th{\acute{e}}{\hat{a}}tre$ commence ${\grave{a}}$ lire le $th{\acute{e}}{\hat{a}}tre$, l'analyse et juge son valeur. Il arrive souvent qu'on juge avec intutition. On dit que c'est une critique d'impressionnisme. Cette critique est subjective, mais pas objective. La $s{\acute{e}}miotique$ de Saussure offre la $m{\acute{e}}thodologie$ scientifique ${\grave{a}}$ la critique. A $c{\hat{o}}t{\acute{e}}$ de la critique d'impressionnisme qui est subjective, la $s{\acute{e}}miotique$ peut expliciter la raison objective. On ${\acute{e}}tait$ admiratif devant sa scientisme, pourtant $apr{\grave{e}}s$ quoi on critique sa non-$subjectivit{\acute{e}}$ et sa non-$historicit{\acute{e}}$. Dans l'opposition de $l^{\prime}objectivit{\acute{e}}$ et de la $subjectivit{\acute{e}}$, on tente de rechercher un model $int{\acute{e}}gr{\acute{e}}$ dialectiquement entre l'impressionisme(subjective) et la scientisme(objective). Pour cela, on doit aux Ecrits de linguistique $g{\acute{e}}n{\acute{e}}rale$ ($publi{\acute{e}}$ en 2002 chez Gallimard). Ces Ecrits nous aident ${\grave{a}}$ amener la $s{\acute{e}}miotique$ $ferm{\acute{e}}e$ sur la $s{\acute{e}}miotique$ ouverte et ${\grave{a}}$ $red{\acute{e}}couvrir$ la $pens{\acute{e}}e$ de Saussure. Ils nous font ouvrir un nouveau champ de recherche pour la $s{\acute{e}}miotique$ ouverte. L'essentiel de la $th{\acute{e}}orie$ saussurienne du signe $d{\acute{e}}pend$ de l'arbitraire et du circulaire du signe. On $red{\acute{e}}couvre$ la notion ${\acute{e}}largie$ du signe, dans Ecrits de linguistique $g{\acute{e}}n{\acute{e}}rale$, contre le courant majeur de linguistique et de structuralisme. Cette notion s'y focalise, ${\grave{a}}$ la valeur, ${\grave{a}}$ la $relativit{\acute{e}}$, ${\grave{a}}$ la $diff{\acute{e}}rence$ et au $syst{\grave{e}}me$. Avec elle, on tente d'adopter la $s{\acute{e}}miotique$ ouverte pour rechercher une $m{\acute{e}}thodologie$ de critique qui se veut objective et ${\grave{a}}$ la fois subjective. Il s'agit d'une difficile combinaison de l'impressionisme et de la scienticisme. Pour cela, la $m{\acute{e}}thodologie$ se $d{\acute{e}}veloppera$ en trois ${\acute{e}}tapes$. $1{\grave{e}}re$ ${\acute{e}}tape$: c'est lire le $th{\acute{e}}{\hat{a}}tre$ comme un signe total pour 1er jugement d'impressionnisme. $2{\grave{e}}me$ ${\acute{e}}tape$: c'est retrouver sa structure invisible dans la $relativit{\acute{e}}$ des signes. $3{\grave{e}}me$ ${\acute{e}}tape$: c'est juger, dans leur $relativit{\acute{e}}$, comment les $d{\acute{e}}tails$ de signes se fonctionnent. C'est lire les $d{\acute{e}}tails$ de signes et puis $r{\acute{e}}affirmer$ le jugement en $1{\grave{e}}re$ ${\acute{e}}tape$. Selon les $derni{\grave{e}}res$ deux ${\acute{e}}tapes$, on pourra comparer le premier jugement (impressif) et le dernier jugement (objectif), et enfin s'assumer comme critique. Selon la $m{\acute{e}}thodologie$ $propos{\acute{e}}e$, on pratique la critique sur ${\acute{e}}crit$ par Jean Genet, et mise en $sc{\grave{e}}ne$ par Lee Youn-Taek et par Park Jung-Hee. Pour la critique intertextuelle, on la fera en comparant les deux spectacles avec la $pi{\grave{e}}ce$ de Jean Genet. $D^{\prime}apr{\grave{e}}s$ la comparaison, Lee Youn-Taek met en $sc{\grave{e}}ne$ avec $fid{\acute{e}}lit{\acute{e}}$ la structre et les signes de $d{\acute{e}}tail$ de l'auteur, Park Jung-Hee change sa structre et ses signes pour mettre en $sc{\grave{e}}ne$ la $pi{\grave{e}}ce$ de Genet. Ils se $diff{\grave{e}}rent$ l'un et l'autre: Lee incite le discours de la classe sociale dans le spectacle, et Park y incite le discours du $d{\acute{e}}sir$. La $diff{\acute{e}}rence$ des signes dans la $relativit{\acute{e}}$ apporte la $diff{\acute{e}}rence$ de la signification de discours $th{\acute{e}}{\hat{a}}tral$, et enfin se font changer les significations de deux spectacles.

• Journal of Physiology & Pathology in Korean Medicine
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• v.21 no.5
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• pp.1081-1086
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• 2007

This study was performed to investigate the medicinal effects of the herbal combination extracts-2 (HCE-2), consisting of Artemisia capillaris Thunb., Lonicera japonica Thunb., Prunella vulgaris var. lilacina, and Hovenia dulcis Thunb. on the alcohol-induced liver injury in rats. The rats were randomly divided into four groups: normal group (n =6), non-treated control group (n =6), saline-treated group (n =6) and the herbal combination extract (HCE-2)-treated group (n =6). The rats in the alcohol-loaded groups were orally administered with ethanol at a daily dose of 4 g/kg-body weight for 5 weeks. Thirty minutes before the ethanol injection, saline or herbal combination extracts was administered by using a gastrogavage. Blood and liver tissue samples were taken out from the hearts and livers of the rats, respectively, on 15th and 38th days. The activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were measured using an enzyme-linked immunosorbent assay (ELISA). We also investigated the protective effect of the herbal combination extracts by Hematoxylin-Eosin staining on histological sections of rat liver. In this study, the oral administration of the herbal combination extracts significantly reduced the serum levels of AST and ALT, which had been raised by alcohol-induced liver injury. Histological analysis and apparent observation of liver also showed the preventive effect of the herbal combination extracts in a chronic alcohol-induced rat model. Theses results revealed that the herbal combination extracts effectively prevented hepatic damage consequent to the chronic exposure to repetitive administration of ethanol and could be used as a primary resource of a health beverage or herbal medicine, alleviating the alcohol-induced hepatic injury and hangover symptoms.

• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1135-1144
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• 2023

Many agricultural reservoirs in South Korea, constructed before 1970, have become aging facilities. The majority of small-scale reservoirs lack measurement systems to ascertain basic specifications and water levels, classifying them as unmeasured reservoirs. Furthermore, continuous sedimentation within the reservoirs and industrial development-induced water quality deterioration lead to reduced water supply capacity and changes in reservoir morphology. This study utilized Light Detection And Ranging (LiDAR) sensors, which provide elevation information and allow for the characterization of surface features, to construct high-resolution Digital Surface Model (DSM) and Digital Elevation Model (DEM) data of reservoir facilities. Additionally, bathymetric measurements based on multibeam echosounders were conducted to propose an updated approach for determining reservoir capacity. Drone-based LiDAR was employed to generate DSM and DEM data with a spatial resolution of 50 cm, enabling the display of elevations of hydraulic structures, such as embankments, spillways, and intake channels. Furthermore, using drone-based hyperspectral imagery, Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) were calculated to detect water bodies and verify differences from existing reservoir boundaries. The constructed high-resolution DEM data were integrated with bathymetric measurements to create underwater contour maps, which were used to generate a Triangulated Irregular Network (TIN). The TIN was utilized to calculate the inundation area and volume of the reservoir, yielding results highly consistent with basic specifications. Considering areas that were not surveyed due to underwater vegetation, it is anticipated that this data will be valuable for future updates of reservoir capacity information.

• Proceedings of the Korean Environmental Sciences Society Conference
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• 1998.10a
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• pp.2-4
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• 1998

Proliferation of Nocardia amarae cells in activated sludge has often been associated with the generation of nuisance foams. Despite intense research activities in recent years to examine the causes and control of Nocardia foaming in activated sludge, the foaming continued to persist throughout the activated sludge treatment plants in United States. In addition to causing various operational problems to treatment processes, the presence of Nocardia may have secondary effects on the fate of heavy metals that are not well known. For example, for treatment plants facing more stringent metal removal requirements, potential metal removal by Nocardia cells in foaming activated sludge would be a welcome secondary effect. In contrast, with new viosolid disposal regulations in place (Code o( Federal Regulation No. 503), higher concentration of metals in biosolids from foaming activated sludge could create management problems. The goal of this research was to investigate the metal sorption property of Nocardia amarae cells grown in batch reactors and in chemostat reactors. Specific surface area and metal sorption characteristics of N. amarae cells harvested at various growth stages were compared. Three metals examined in this study were copper, cadmium and nickel. Nocardia amarae strain (SRWTP isolate) used in this study was obtained from the University of California at Berkeley. The pure culture was grown in 4L batch reactor containing mineral salt medium with sodium acetate as the sole carbon source. In order to quantify the sorption of heavy metal ions to N amarae cell surfaces, cells from the batch reactor were harvested, washed, and suspended in 30mL centrifuge tubes. Metal sorption studies were conducted at pH 7.0 and ionlc strength of 10-2M. The sorption Isotherm showed that the cells harvested from the stationary and endogenous growth phase exhibited significantly higher metal sorption capacity than the cells from the exponential phase. The sequence of preferential uptake of metals by N. amarae cells was Cu>Cd>Ni. The specific surFace area of Nocardia cells was determined by a dye adsorption method. N.amarae cells growing at ewponential phase had significantly less specific surface area than that of stationary phase, indicating that the lower metal sorption capacity of Nocardia cells growing at exponential phase may be due to the lower specific surface area. The growth conditions of Nocardia cells in continuous culture affect their cell surface properties, thereby governing the adsorption capacity of heavy metal. The comparison of dye sorption isotherms for Nocardia cells growing at various growth rates revealed that the cell surface area increased with increasing sludge age, indicating that the cell surface area is highly dependent on the steady-state growth rate. The highest specific surface area of 199m21g was obtained from N.amarae cell harvested at 0.33 day-1 of growth rate. This result suggests that growth condition not only alters the structure of Nocardia cell wall but also affects the surface area, thus yielding more binding sites of metal removal. After reaching the steady-state condition at dilution rate, metal adsorption isotherms were used to determine the equilibrium distributions of metals between aqueous and Nocardia cell surfaces. The metal sorption capacity of Nocardia biomass harvested from 0.33 day-1 of growth rate was significantly higher than that of cells harvested from 0.5- and 1-day-1 operation, indicatng that N.amarae cells with a lower growth rate have higher sorpion capacity. This result was in close agreement with the trend observed from the batch study. To evaluate the effect of Nocardia cells on the metal binding capacity of activated sludge, specific surface area and metal sorption capacity of the mixture of Nocardia pure cultures and activated sludge biomass were determined by a series of batch experiments. The higher levels of Nocardia cells in the Nocardia-activated sludge samples resulted in the higher specific surface area, explaining the higher metal sorption sites by the mixed luquor samples containing greater amounts on Nocardia cells. The effect of Nocardia cells on the metal sorption capacity of activated sludge was evaluated by spiking an activated sludge sample with various amounts of pre culture Nocardia cells. The results of the Langmuir isotherm model fitted to the metal sorption by various mixtures of Nocardia and activated sludge indicated that the mixture containing higher Nocardia levels had higher metal adsorption capacity than the mixture containing lower Nocardia levels. At Nocardia levels above 100mg/g VSS, the metal sorption capacity of activate sludge increased proportionally with the amount of Noeardia cells present in the mixed liquor, indicating that the presence of Nocardia may increase the viosorption capacity of activated sludge.