• Journal of the Korean Society for Industrial and Applied Mathematics
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• v.24 no.2
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• pp.143-159
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• 2020

We propose a consistent numerical method for elliptic interface problems with nonhomogeneous jumps. We modify the discontinuous bubble immersed finite element method (DB-IFEM) introduced in (Chang et al. 2011), by adding a consistency term to the bilinear form. We prove optimal error estimates in L² and energy like norm for this new scheme. One of the important technique in this proof is the Bramble-Hilbert type of interpolation error estimate for discontinuous functions. We believe this is a first time to deal with interpolation error estimate for discontinuous functions. Numerical examples with various interfaces are provided. We observe optimal convergence rates for all the examples, while the performance of early DB-IFEM deteriorates for some examples. Thus, the modification of the bilinear form is meaningful to enhance the performance.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.6
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• pp.989-995
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• 2010

The aim of this study was to investigate the effect of Taeeumjowuitanggagam-bang(TJV) on the mRNA expression of adipocytokines (TNF-${\alpha}$ and IL-6), and SREBPs. Mice were divided into 4 groups ; a normal group of db/+ mice, a control group of db/db mice, a group (db/db mice) treated with TJV 200 mg/kg, and a group (db/db mouse) treated with TJV 500 mg/kg. They were treated orally with TJV and measured their body weight every other day during 9 weeks. After that, we measured the mRNA expression of adipocytokines (TNF-${\alpha}$ and IL-6) and SREBPs (SREBE-1a and SREBP-1c) in liver, and blood concentration of total cholesterol, triglyceride, too. In addition, liver samples were fixed in 4% PFA for 2 hours and stored in $-70^{\circ}C$. Liver tissues were embedded in Optical cutting temperature(OCT) compound and 30 ${\mu}m$ sections were cut. Tissue sections were stained Oil-Red-O to visualize neutral lipids. Nuclei were stained with hematoxylin solution. In result, the TJV reduced the mRNA expressions of TNF-${\alpha}$ and IL-6 and SREBPs in liver and stained liver tissue less red than control group. However, there was no significant differences in total cholestreol and triglyceride blood concentration and body weight among groups. The TJV has inhibitory effect on the mRNA expression of adipocytokines and SREBPs. Therefore, it is assumed that the TJV is related to inhibiting lipogenesis in the liver

• Journal of Korean Institute of Industrial Engineers
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• v.24 no.2
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• pp.311-322
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• 1998

Modular BOMs are typically used in TWO-Level Master Production Schedule. To solve the problems of Modular BOM generation and efficient DB construction, we proposed Value Clustering Method. Based upon Where-Used matrix of products and components, VCM is the method to find out module by generating product family group value, product value, and component value. We also proposed method to find out information about Modules, algorithms to find out Modules that show Alternative Usage Pattern, and method to find out Modules used in a given product. We also compared the DB creation method by Value Clustering Method and by conventional method. We compared the size of DB in both methods. We mathematically proved that the proposed method is doing better as the size and complexity of product family gets larger and more complicated.

• Magazine of the Korean Society of Agricultural Engineers
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• v.42
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• pp.24-30
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• 2000

A system for evaluating streamflow data (KORSAS) was developed, and is operated using PC based Windows to help the hydrological observation practitioner's working in Korea Water Resources Corporation (KOWACO). This system has modules including; DB access and data management, flow measurement arranging, H-Q relation deriving, area rainfall calculating, flow calculating, and flow evaluating modules. Evaluation of observed streamflow is accomplished through the following processes. First, hourly streamflow data is calculated from water level data stored in a DB server by applying the rating relationship between water level and flow rates derived from the past flow measurements. Second, hourly areal rainfal data is calculated from point data stored in the DB server by applying Thiessen networks. Third, hydrographs are displayed on a daily, weekly, monthly, or seasonal duration basis, and are compared to hydrographs of reservoir inflow, hydrographs at water level observation stations and hydrographs derived from simulated results using models.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.5
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• pp.733-739
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• 1987

In this paper, variable threshold detection with weighted pulse code modulation-encoded signals transmitted over Gaussian channels has been investigated. Each bit in the \ulcornerlaw PCM word is weighted according to its significance in the transmitter. It the output falls into the erasure zone, the regenerated sample replaced by interpolation or prediction. To overall system signal to noise ratio for BPSK/PCM speech signals of this technique has been found. When the input signal level was -17 db, the gains in overall signal s/n compared to weighted PCM and variable threshold detection were 5 db and 3 db, respectively. Computer simulation was performed generating signals by computer. The simulation was in resonable agreement with our theoretical prediction.

• Korean Journal of Construction Engineering and Management
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• v.13 no.5
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• pp.12-24
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• 2012

The Risks in undertaking a construction project comes from many sources and often involves many participants in the project. This study has identified various kinds of risks, assessed the risk factors quantitatively and suggested risk management method for response pertinent in Design Build(Turn Key)type of projects in Korean context. A questionnaire was designed comprising of 145 possible risks in all types of construction projects. The population from owner, consultant and contractor groups was asked to indicate the risks applicable in DB projects. 25 numbers of critical risks in DB projects were identified and further analyzed for reveling inherent relationship between them through factor analysis. Factor analysis revealed 8 risk factors in DB projects. Construction site related, contract related and design related risk factor consisted about 72% of total risk weight. It has been found out about 6%, while considering the mutual dependency, it is about 10% of total cost of DB project. Therefore, It is suggested that 6% to 10% of construction amount as contingency has to be made provision for risk responses in the DB projects.

• Journal of the Korean Institute of Gas
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• v.12 no.1
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• pp.13-18
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• 2008

Vibration velocity induced by earthquakes or external vibration sources is one of the integrity assessment indexes, and is also a representative value used to describe the amount of vibration because it is based on a proportional relationship with the damage scale. In this study, the vibration velocity criterion for structures is first examined. Then, based on the velocity criterion, an integrity assessment is performed. Burial condition is set up based on the "Highway and Local Road Design Criteria" with API 5L Gr. X65 pipeline(D=762 mm). The FE model considers DB-24 vehicle load as a time function with a varying velocity in the range of $20{\sim}160\;km/h$. Maximum vibration velocity occurs at v=80 km/h and decreases after v=80 km/h. The maximum vibration velocity of buried pipeline by DB-24 loads is about 0.034 cm/s. The velocity that occurs is in the range of allowable values for each vibration velocity criterion. The wave propagation velocity was identified based on attenuation law and the minimum value appears at vehicle velocity 80 km/h that has maximum vibration velocity.

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.331-342
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• 2009

A reliability analysis of the fatigue failure of highway steel bridges was performed by applying the Miner's fatigue damage rule for the fatigue design truck proposed for the LRFD code and for the current DB 24 truck. The limit state function for fatigue failure is expressed as a function of various random variables that affect fatigue damage. Among these variables, the statistical parameters for the equivalent moment, the impact factor, and the loadometer were obtained by analyzing recently measured domestic traffic data, and the parameters for the fatigue strength, the girder distribution factor, and the headway factor were obtained from the measured data reported in literature. Based on the reliability analysis, the fatigue truck model for the LRFD code was proposed. After applying the proposed fatigue truck to the LRFD code, 16 composite plate and box girder bridges were designed based on the LRFD method, and the LRFD design results for the fatigue limit state were compared with those by the current KHBDC.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.35-43
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• 2006

In this paper, procedures and research results involved in the development of glass reinforced composite bridge deck of hollow section were presented. Laminate design for the 3 cell deck section was performed. Structural characteristics such as serviceability, strength, failure and stability for DB24 load were analytically studied through the finite element analysis for the composite deck plate girder bridge. Composite deck tube was fabricated with pultrusion and extensive tests such as flexural test, girder-connection test, barrier-connection test, compression fatigue test and flexural fatigue test were carried out to evaluate structural behavior experimentally. Also, field load test was conducted for the demonstration plate girder bridge with composite deck and requirements for the strength and serviceability were reviewed.

• Endocrinology and Metabolism
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• v.37 no.1
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• pp.96-111
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• 2022

Background Diabetic nephropathy (DN) is characterized by albuminuria and accumulation of extracellular matrix (ECM) in kidney. Transforming growth factor-β (TGF-β) plays a central role in promoting ECM accumulation. We aimed to examine the effects of EW-7197, an inhibitor of TGF-β type 1 receptor kinase (ALK5), in retarding the progression of DN, both in vivo, using a diabetic mouse model (db/db mice), and in vitro, in podocytes and mesangial cells. Methods In vivo study: 8-week-old db/db mice were orally administered EW-7197 at a dose of 5 or 20 mg/kg/day for 10 weeks. Metabolic parameters and renal function were monitored. Glomerular histomorphology and renal protein expression were evaluated by histochemical staining and Western blot analyses, respectively. In vitro study: DN was induced by high glucose (30 mM) in podocytes and TGF-β (2 ng/mL) in mesangial cells. Cells were treated with EW-7197 (500 nM) for 24 hours and the mechanism associated with the attenuation of DN was investigated. Results Enhanced albuminuria and glomerular morphohistological changes were observed in db/db compared to that of the nondiabetic (db/m) mice. These alterations were associated with the activation of the TGF-β signaling pathway. Treatment with EW-7197 significantly inhibited TGF-β signaling, inflammation, apoptosis, reactive oxygen species, and endoplasmic reticulum stress in diabetic mice and renal cells. Conclusion EW-7197 exhibits renoprotective effect in DN. EW-7197 alleviates renal fibrosis and inflammation in diabetes by inhibiting downstream TGF-β signaling, thereby retarding the progression of DN. Our study supports EW-7197 as a therapeutically beneficial compound to treat DN.