• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.492-492
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• 2017

강수량은 지상에 내린 물의 총량으로 홍수 및 갈수량 산정에 있어서 유출특성을 파악하는데 중요한 자료이다. 부정확한 자료 및 수문분석기법에 의한 수자원량의 추정은 수공구조물의 설계 시과소 또는 과다 설계로 문제를 가져올 수 있으며, 수리 수문분석시스템의 효율적인 운영에 많은 지장을 초래하게 될 수 있다. 특히 강수량자료를 기초로 하는 홍수예보 및 갈수예보 모형들은 그 입력치인 강수량자료의 정확도가 큰 비중을 차지하게 된다. 강수량은 면적 강수량을 대표할 수 있는 위치에서 관측되어야 점 강수량을 면적 강수량으로 환산하는데서 발생하는 오차를 최소화 할 수 있다. 최근 강수 특성은 과거에 비해 시공간적으로 매우 불규칙해졌으며, 특히 짧은 지속시간 동안에 많은 양의 강우가 집중되고 있다. 강수량조사망은 이와 같은 강수 특성 변화를 충분히 반영할 수 있어야 한다. 강수 특성을 반영하여 수문조사, 홍수예보, 강우레이더에 활용하기 위해서는 기존 강수량조사망에 대한 재평가가 선행되어야 하며, 재평가된 결과를 토대로 강수량조사망을 설계하여야 한다. 또한 강수량관측소는 그 자체에 여러가지 오차를 내재하는데, 이는 바람의 영향, 증발, 주변 환경 변화 등 다른 여러 가지 오차들이다. 이러한 오차의 발생을 최소화하기 위해서는 관측시설의 유지관리가 매우 중요하다. 강수량자료의 품질 문제를 최소화하여 강수량자료의 품질을 향상시키기 위해서는 기존 강수량관측소 및 운영현황에 대한 명확한 고찰이 선행되어야 하며, 기존의 강수량조사망에 어떠한 문제점 등이 내포되어 있는지에 대한 객관적인 평가를 통하여 수문조사, 홍수예보, 강우레이더 활용에 적합한 강수량조사망 구축이 필요하다. 본 연구에서는 영산강홍수통제소 관할 유역의 강수량관측소 67개소를 조사 평가하여 수문조사, 물관리, 강우레이더의 활용에 필요한 강수량조사망을 구축하였다. 이에 따라 신설 강수량관측소는 14개소가 필요한 것으로 나타났으며, 이 경우 평균 시강수량의 추정 불확실도가 0.2 이상인 영역은 19.3 %에서 10.6 %로 줄어들며, 연평균 강수량의 추정 불확실도가 0.2 이상인 영역은 9.0 %에서 4.7 %로 줄어드는 것으로 나타났다. 또한 강수량조사망 구축에 필요한 강수량관측소 설치, 위치선정, 배치 등에 관한 기준 및 유지관리에 필요한 사항을 제시하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.65-65
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• 2016

Various types of flow conditions are developed in the region just downstream of hydraulic structures such as weir and drop structures. One of distinct flow conditions occurred downstream of drop structures is the wave type flow with undular hydraulic jump formation. We present three-dimensional numerical simulations of a wave type flow formed downstream of a stepped weir which were experimentally investigated by Kang et al. (2010). The turbulent flow over the weir structure is modeling using the unsteady Reynolds-averaged Navier-Stokes (URANS) simulation employing the Spalart-Allmaras one equation model and the detached eddy simulation. Numerical modeling and the performance of turbulence modeling approaches are evaluated by comparing with the experimental measurements in terms of the free surface variation, the shapes and sizes of undular wave, roller near at free surface, recirculation zone near the channel bottom downstream of the structures, and streamwise velocity profiles at selected longitudinal locations.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.423-423
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• 2019

RGB나 다중분광영상은 높은 공간 해상도로 인해 크기가 작은 물질의 클래스를 부여하는데 있어서는 효과적이지만 분광해상도가 낮아 다양한 종류의 지표물 분류 및 분광적으로 미세한 차이를 보이는 대상 체간의 분류에는 한계를 가지고 있다. 그러나 초분광 영상(Hyperspectral Image)은 대상 객체의 분광 반사곡선을 수백개의 연속적인 분광 파장대 영역으로 상세하게 해당 물체의 정보를 취득할 수 있는 기능을 가지고 있다. 최근 국내에서도 초분광 영상을 이용한 토지피복도 작성 및 환경 모니터링 등 다양한 분야에 적용하기 위한 연구가 시도되고 있다. 최근에는 드론과 같은 소형 UAV를 활용하여 경제적인 비용으로 시공간해상도가 높은 영상을 획득하는 것이 가능하게 되었으며 분광정보를 수집하는 영상 장비의 발전으로 드론에 탑재가 가능한 경량의 소형 초분광센서가 개발됨으로써 보다 높은 분광해상도의 영상을 취득할 수 있게 되었다. 본 연구에서는 효율적인 하천환경조사를 위해 UAV를 활용하여 고해상도 초분광 영상을 취득하였으며, 차원축소법과 분류기 적용에 따른 공간 분류 정확도 분석을 통해 하천환경에 대한 분류 및 평가를 실시하였다. 연구지역에서 획득한 초분광 영상은 노이즈로 인한 영향을 줄이고자 MNF와 PCA 기법으로 차원축소를 수행하였으며, MLC(Maximum Likelihood Classification)와 SVM(Support Vector Machine), SAM(Spectral Angle Mapping) 감독분류기법을 적용하여 하천환경특성에 따른 공간분류를 수행하였다. 연구 결과 MNF기법으로 차원 축소한 영상을 적용하여 MLC 감독분류를 수행하였을 때 가장 높은 분류정확도를 얻을 수 있었으나, 일부 클래스 및 수역의 경계와 그림자 공간에서 주로 오분류가 나타나는 것을 확인할 수 있었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.6
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• pp.243-250
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• 2018

This paper designs and implements a smart care system for the senior citizen who lives alone. Recently, as the level of living has increased due to the rapid improvement of medicine, living standard and environment, the proportion of the elderly population is increasing. In addition, the proportion of the elderly living alone, which is increasing with the aging society, suggests that the provision of services such as the elder care system and emergency notification is becoming an important issue. However, since the existing emergency notification technology analyzes fixed CCTV images, it is difficult to monitor in the blind spot of CCTV and to move to a place where the camera is not installed. There is a problem that it can not be performed. Therefore, in this paper, we design and develop a smart care system that utilizes robot and object tracking technology that can move in real time to overcome these shortcomings. This enables real-time monitoring regardless of the location, and prompts for assistance in case of an emergency, so that it can provide convenience to cares and assistants.

• Journal of Society of Preventive Korean Medicine
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• v.23 no.1
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• pp.83-94
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• 2019

Objective : This study investigated the effects of concentrated and lyophilized blue honeysuckle powders (BH) on the pharmacokinetics (PK) of sorafenib were observed. Method : The blood was collected at 0.5 hr before single oral treatment of sorafenib (40 mg/kg) or sorafenib with BH (400, 200 and 100 mg/kg) mixed formulas administration, and 0.5, 1, 2, 3, 4, 6, 8 and 24 hrs after the end of single or mixed formula administration. Plasma concentrations of sorafenib were analyzed using LC-MS/MS methods. Tmax, Cmax, AUC, $t_{1/2}$ and $MRT_{inf}$ of sorafenib were analysis as compared with sorafenib single treatment. Results : Single oral administration of mixed formulas induced significant increases of plasma sorafenib concentrations from 0.5 hr after end of administration throughout all blood collected time points, as compared with sorafenib single formula treated rats, and significant decreases of sorafenib Tmax with increases of Cmax, $AUC_{0-t}$ and $AUC_{0-inf}$ were detected in sorafenib and BH 400 mg/kg mixed formulation treated rats as compared with sorafenib single formula treated rats, respectively. Inaddition, sorafenib and BH 200 or 100 mg/kg mixed formula treated rats also showed significant increases of sorafenib Cmax, $AUC_{0-t}$ and $AUC_{0-inf}$, respectively. Conclusions : According to these results, mixed formulation of BH with sorafenib increased the bioavailability of sorafenib through the increment of the absorptions.

• Corrosion Science and Technology
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• v.19 no.6
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• pp.296-301
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• 2020

Failure analysis on the welded type 304 pipe used for cooling water piping in the district heating primary side was conducted. Inorganic elements and bacteria in the cooling water and in corrosion products were analyzed, and the weldment was inspected by microscopy and a sensitization test. Corrosion damages were observed in the heat-affected zone, on weld defects such as incomplete fusion or excessive penetration caused by improper welding, or/and at the 6 o'clock position along the pipe axial direction. However, the level of concentration of chloride in the cooling water as low as 80 ppm has been reported to be not enough for even a sensitized type 304 steel, meaning that the additional corrosive factor was required for these corrosion damages. The factor leading to these corrosion damages was drawn to be the metabolisms of the types of bacteria, which is proved by the detection of proton, sulfur containing species, biofilms, and both bacteria and corrosion product analyses.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1B
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• pp.63-71
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• 2009

Riprap filter should be installed around the pier to prevent riprap subsidence due to sediment winnowing or leaching between the riprap and bed layers. However, riprap protection without filters is commonly applied in the field because of ambiguous specifications and technical and economical difficulties to install the filter layer. Therefore, the hydraulic experiments were conducted in this study to measure and analyze the riprap subsidence quantitatively with different conditions for thickness of riprap layer, approached velocity, sizes of riprap and bed material. As the velocity was increased and size of bed material and thickness of riprap layer were decreased, the subsidence was increased. Consequently, the dimensionless riprap subsidence equation was derived using the synthesized experimental results. The results of this study could be employed as a standard criterion or predictor to evaluate the subsidence stability.

• Ecology and Resilient Infrastructure
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• v.10 no.4
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• pp.201-207
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• 2023

Suspended solid in river is resource serious contamination. Suspended solid have a pernicious influence to fish and aquatic ecosystem. Flood and sediment and land use in river are largely[mainly] responsible of suspended solid. Especially, resuspension phenomenon of sediment will be dangerous effect to aquatic ecosystem. Study of fish and aquatic ecosystem on suspended solidus slight in fresh water. This study was basic research to manage fish and aquatic ecosystem on turbidity. It was conducted to analyze and monitor fish response on turbidity. Result in this study was confirmed the insensitive and die of fish on reduction of oxygen supply.

• Animal cells and systems
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• v.15 no.3
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• pp.203-210
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• 2011

In the present study, we examined the effects of caffeine on food intake and body weight, and pro-opiomelanocortin (POMC) and agouti-related protein (AgRP) expression in the hypothalamus. Rats were administered intraperitoneally with 100 mg/kg caffeine (a high, non-toxic dose) or saline during the light phase. Intraperitoneal administration of caffeine induced a significant reduction in food intake and body weight 12 hr after treatment. In addition, POMC expression was significantly increased and AgRP expression was decreased in the arcuate nucleus (Arc) after caffeine treatment. These results demonstrate that administration of caffeine up-regulates POMC expression and down-regulates AgRP expression in the Arc, suggesting that the activation of the hypothalamic POMC neurons and inhibition of the AgRP neurons might play a role in the regulation of food intake and body weight by caffeine.

• Journal of Periodontal and Implant Science
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• v.50 no.6
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• pp.368-378
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• 2020

Purpose: Vitamin D deficiency may cause bone loss and increased inflammation, which are well-known symptoms of periodontal disease. This study investigated whether serum 25-hydroxyvitamin D (25(OH)D) levels are associated with periodontal disease status and tooth loss. Methods: Cross-sectional data from 5,405 individuals aged ≥50 years (2,253 males and 3,152 females) were obtained from the 2008-2010 Dong-gu study, a prospective cohort study of risk factors for chronic diseases. Periodontal examinations were conducted to evaluate the number of remaining teeth, the periodontal probing depth (PPD), the clinical attachment level (CAL), and bleeding on probing. The percentages of sites with PPD ≥4 mm and CAL ≥4 mm were recorded for each participant. The severity of periodontitis was classified using the Centers for Disease Control and Prevention and the American Academy of Periodontology case definitions. Serum 25(OH)D levels were classified as reflecting severe deficiency, deficiency, insufficiency, or sufficiency. Multivariate linear regression analysis was performed to assess the associations of serum 25(OH)D levels with periodontal parameters and the number of remaining teeth after adjusting for confounders including age, smoking status, alcohol consumption status, month of blood collection, and physical activity. Multivariate logistic regression was used to evaluate the association between serum vitamin D levels and severe periodontitis. An overall statistical analysis and a stratified analysis by sex were performed. Results: Overall, the rates of severe deficiency, deficiency, insufficiency, and sufficiency were 6.5%, 67.9%, 22.4%, and 3.2%, respectively. After adjustment for confounders, vitamin D levels were directly associated with the number of remaining teeth, an association that was significant in males, but not in females. Sufficient serum 25(OH)D was associated with a low frequency of severe periodontitis. Conclusions: This population-based cross-sectional study indicates that low serum 25(OH) D is significantly associated with tooth loss and severe periodontitis in Koreans aged 50 years and older.