• 한국농공학회논문집
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• 제66권3호
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• pp.1-14
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• 2024

Gaining an accurate 3D stream geometry has become feasible with Unmanned Aerial Vehicle (UAV), which is crucial for better understanding stream hydrodynamic processes. The objective of this study was to investigate series of filters to remove stream vegetation and propose the best method for generating Digital Terrain Models (DTMs) using UAV-based point clouds. A stream reach approximately 500 m of the Bokha stream in Icheon city was selected as the study area. Point clouds were obtained in August 1st, 2023, using Phantom 4 multispectral and Zenmuse L1 for Structure from Motion (SfM) and Light Detection And Ranging (LiDAR) respectively. Three vegetation filters, two morphological filters, and six composite filters which combined vegetation and morphological filters were applied in this study. The Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) were used to assess each filters comparing with the two cross-sections measured by leveling survey. The vegetation filters performed better in SfM, especially for short vegetation areas, while the morphological filters demonstrated superior performance on LiDAR, particularly for taller vegetation areas. Overall, the composite filters combining advantages of two types of filters performed better than single filter application. The best method was the combination of Progressive TIN (PTIN) and Color Indicies of Vegetation Extraction (CIVE) for SfM, showing the smallest MAE of 0.169 m. The proposed method in this study can be utilized for constructing DTMs of stream and thus contribute to improving the accuracy of stream hydrodynamic simulations.

• 대한의용생체공학회:의공학회지
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• 제36권4호
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• pp.135-142
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• 2015

Outflow cannulation site of left ventricular assist device(LVAD) chosen by considering anatomical structure of thoracic cavity and vascular system. Though outflow cannulation site influences blood perfusion at each branch, there is no standard rule or quantitative data. In this study, we computed the amount of blood perfusion at each arterial branch numerically according to outflow cannulation sites(ascending aorta, aortic arch, descending aorta). We generated computational meshes to the three-dimensionally reconstructed arterial system. Clinically measured arterial pressure were used for inlet boundary condition, porous media were applied to mimic blood flow resistance. Blood perfusion through left common carotid artery was 2.5 times higher than other cases, and that through right common carotid artery was 1.1 times higher than other branches. Although this is simulation study, will be useful reference data for the clinical study of LVAD which considers blood perfusion efficiency.

• 융합신호처리학회논문지
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• 제3권2호
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• pp.71-75
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• 2002

본 논문은 여러 프로세스제어에 사용되는 PID제어기의 최적 자동동조에 관한 새로운 방법을 제안하고자 한다. 이 방법은 먼저, 제어대상의 계단응답으로부터 모델링된 1차 지연계를 Pade 근사화 하고, Ziegler-Nickels의 한계감도 법으로 초기계수를 결정한 후 유전자알고리즘의 부모세대의 2진 스트링에 적합도 값으로 입력시켜 선택 교배 및 돌연변이를 통하여 새로운 자손세대를 형성한다 이 방법은 Ziegler-Nickels로 구한 출력특성보다 더욱 좋은 특성을 가지며 입력변수 K, L, T의 학습범위가 없어져 응용범위가 확장되는 장점을 가지고 있다.

• 식품보건융합연구
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• 제6권1호
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• pp.17-20
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• 2020

Wheat is the most abundant crop in the world, accounting for one third of the world's population diet. In Ukraine, wheat is in fact, in addition to its nutritional value, a national symbol of the state. Therefore, the main thesis on the development of modern plant growing in Ukraine is the reduction of costs and the introduction of innovative technologies. The quality of grain and seed depends on many factors, namely: agro-climatic conditions, sowing condition of the seed material, quality characteristics of the soil, yielding properties of seeds, pre-sowing seed treatment. etc. For this purpose, the photosynthesis and intensity of photosynthesis need to be limited to the width of the leaf and the height of the leaves by a smaller cut of the stem. It is extremely important to ensure that the head and side pagons of wheat are in good condition. All parameters are often secured by the technology of grain preparation before delivery. Prior to this technology, it is possible to introduce processing of the material in the form for the development of the material. This article presents the effectiveness of the use of infrared irradiation for the pre-sowing treatment of winter wheat seeds in Sekobra Research, Germany.

• 융합정보논문지
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• 제12권3호
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• pp.126-131
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• 2022

비만은 에너지의 섭취와 소비의 불균형으로 지방조직이 비정상적으로 분화하면서 생기는 대사질환으로 알려져있다. 본 연구에서는 본 연구는 적양파 추출물 처리에 따른 Pancreatic lipase 억제, 지방세포분화 억제 활성을 확인하고자 하였다. 적양파추출물 처리에 따른 활성은 지방세포 분화 및 관련 유전자에 대한 평가는 3T3-L1 지방전구세포를 이용하고 Real-Time PCR을 통하여 확인하였다. 실험 결과, Pancreatic lipase 활성 억제 실험에서 적양파 추출물은 농도 의존적으로 lipase 활성을 억제하였다. 지방세포분화 실험을 수행한 결과, insulin, dexamethasone, 3-isobutyl-1-methylxanthine(MDI)등으로 분화 유도된 3T3-L1 세포에서 적양파 추출물은 지방전구세포의 분화를 억제하였으며 동시에 지방구 형성을 억제하는 것으로 나타났다. 또한, 지방전구세포의 분화 과정과 관련된 C/EBP-α, C/EBP-β, PPAR-γ의 발현을 억제하였다. 본 실험에서 적양파 추출물은 지방분해효소를 억제하며, 지방전구세포 분화와 관련된 유전자 발현을 억제함으로써 지방세포 분화 및 지방구형성을 억제할 수 있는 항비만 소재로의 개발 가능성이 높다고 판단된다.

• 한국산업융합학회 논문집
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• 제26권6_2호
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• pp.1047-1053
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• 2023

An experimental study was performed on the collision nozzle system that generates microbubble by air self-suction using a venturi nozzle. This study experimentally investigates the pressure of a pump and a dissolution tank, water flow rate, air self-suction amount and microbubble generation amount. The experimental conditions were varied by changing the diameter of the collision nozzle (d_e=4,5,6,7,8mm), the pumping power(0.5hp, 1.0hp) and the capacity of the dissolution tank(4.4L, 8/8L). The pressure change of the pump according to the outlet diameter of the collision nozzle showed that the 1.0hp pump power operated more stably than the 0.5hp pump. The pressure change in the dissolution tank was shown to decrease rapidly as the outlet diameter of the nozzle increased. The flow rate of recirculating water was shown to increase as the nozzle diameter increased. Additionally, it was shown that the pump capacity of 1.0hp increased the flow rate more than that of 0.5hp. The self-suction air flow rate was shown to occur above d_e=6mm, and the air flow rate increased as the nozzle diameter increased. Also, as the pump capacity increased, the self-suction amount of air increased. It was shown that the amount of microbubble less than 50mm generated was maximum when the nozzle diameter was 6mm, the pump power was 1.0hp, and the dissolution tank capacity was 8.8L.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2004년도 봄 학술발표회 발표논문집
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• pp.245-248
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• 2004

다대포 갯벌의 YP는 0.06~0.13 mg/L이었고 진우도의 TP는 0.06~0.11 mg/L로 조사시기별로는 두 조사지역간 차이는 없었고 TN은 다대포의 경우 1.44~2.87 mg/L, 진우도는 0.15~1.09 mg/L로 조사되어 매 조사시기마다 진우도보다는 다대포에서 월등히 높았으며 두 지역 모두 해역의 어염등급에 비추어볼 때 상당히 오염이 진행된 상태였다. 조사된 미세조류는 Navicula, Nitzschia, Cyclotella, Cymbella, Synedra 등 13속 26종류로 호청수성 조은 Achnanthes convergence 등 1속 2종류, 호오염성 종은 Nitzschia palea 등 5속 8종류, 광적응성 종은 Cymbella minuta 등 3속 5종류였으며 매 시기마다 우점을 보인 종은 Nitzschia, Navicula 였다. DAIpo 지수는 다대포의 경우, 평균 31.1 진우도는 평균 48.4로 조사되어 비교적 낮은 DAIpo 값을 보였지만 계절별로는 다대포와 진우도의 경우 모두 봄인 5월에 가장 높은 DAIpo 값으로 비슷한 경향을 보였으나 다대포의 경우에서는 매 계절마다 진우도보다 더 DAIpo값이 낮게 조사되었다. DAIpo 값으로부터 갯벌의 오염도를 판정하면 다대포는 $\alpha$-중부수성, 진우도는 $\beta$-중부수성에 해당하여 다대포의 경우가 진우도보다 더 오염이 심한 것으로 조사되었다.

• Applied Science and Convergence Technology
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• 제26권3호
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• pp.47-49
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• 2017

Photocurrent enhancement has been investigated in monolayer (1L) $MoS_2$ with PbS quantum dots (QDs). A metal-semiconductor-metal (Au-1L $MoS_2$-Au) junction device is fabricated using a standard photolithography method. Considerably improved photo-electrical properties are obtained by coating PbS QDs on the Au-1L $MoS_2$-Au device. Time dependent photoconductivity and current-voltage characteristics are investigated. For the QDs-coated $MoS_2$ device, it is observed that the photocurrent is considerably enhanced and the decay life time becomes longer. We propose that carriers in QDs are excited and transferred to the $MoS_2$ channel under light illumination, improving the photocurrent of the 1L $MoS_2$ channel. Our experimental findings suggest that two-dimensional layered semiconductor materials combined with QDs could be used as building blocks for highly-sensitive optoelectronic detectors including radiation sensors.

• 한국전기전자재료학회논문지
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• 제30권3호
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• pp.185-191
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• 2017

Cadmium compounds with one dimension (1D) nanostructures have attracted attention for their excellent electrical and optical properties. In this study, vertically aligned CdTe-Si nanostructures with high density were synthesized by several simple chemical reactions. First, l D Te nanostructures were synthesized by silver assisted chemical Si wafer etching followed by a galvanic displacement reaction of the etched Si nanowires. Nanowire length was controlled from 1 to $25{\mu}m$ by adjusting etching time. The Si nanowire galvanic displacement reaction in $HTeO_2{^+}$ electrolyte created hybrid 1D Te-branched Si nanostructures. The sequential topochemical reaction resulted in $Ag_2Te-Si$ nanostructures, and the cation exchange reaction with the hybrid 1D Te-branched Si nanostructures resulted in CdTe-Si nanostructures. Wet chemical processes including metal assisted etching, galvanic displacement, topochemical and cation exchange reactions are proposed as simple routes to fabricate large scale, vertically aligned CdTe-Si hybrid nanostructures with high density.

• 한국전기전자재료학회논문지
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• 제24권11호
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• pp.876-881
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• 2011

The sintering, defect and grain boundary characteristics of Bi-based ZnO chip varistor (1,608 mm size) have been investigated to know the possibility of lowering a manufacturing price by using 100 % Ag inner-electrode. The samples were prepared by general multilayer chip varistor process and characterized by shrinkage, SEM, current-voltage (I-V), admittance spectroscopy (AS), impedance and modulus spectroscopy (IS & MS) measurement. There are no problems to make a chip varistor with 100% Ag inner-electrode in the sintering temperature range of 850~900$^{\circ}C$ for 1 h in air. A good varistor characteristics ($V_n$= 9.3~15.4 V, a= 23~24, $I_L$= 1.0~1.6 ${\mu}A$) were revealed but formed $Zn_i^{{\cdot}{\cdot}}$(0.209 eV) as dominant defect, and increased the distributional inhomogeneity and the temperature instability in grain boundary barriers.