• Journal of Forest and Environmental Science
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• 제35권3호
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• pp.181-188
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• 2019

This study was performed to construct tree species classification map according to three information types (spectral information, texture information, and spectral and texture information) by altitude (30 m, 60 m, 90 m) using the unmanned aerial vehicle images and the object-based classification method, and to evaluate the concordance rate through field survey data. The object-based, optimal weighted values by altitude were 176 for 30 m images, 111 for 60 m images, and 108 for 90 m images in the case of Scale while 0.4/0.6, 0.5/0.5, in the case of the shape/color and compactness/smoothness respectively regardless of the altitude. The overall accuracy according to the type of information by altitude, the information on spectral and texture information was about 88% in the case of 30 m and the spectral information was about 98% and about 86% in the case of 60 m and 90 m respectively showing the highest rates. The concordance rate with the field survey data per tree species was the highest with about 92% in the case of Pinus densiflora at 30 m, about 100% in the case of Prunus sargentii Rehder tree at 60 m, and about 89% in the case of Robinia pseudoacacia L. at 90 m.

• 사물인터넷융복합논문지
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• 제8권2호
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• pp.35-40
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• 2022

농업환경에서 농약방제는 농업인에게 작업 위험성과 높은 노동력을 요구한다. 무인항공기를 활용한 농약방제는 기후, 토지형태, 무인항공기의 특성에 따라 효율성이 다르게 나타난다. 따라서, 살포조건과 환경조건을 고려한 효율적인 무인항공기 농약방제 방안이 요구된다. 본 논문은 작물별 살포조건과 환경정보를 고려한 농업용 무인항공기 기반의 효율적인 농약 방제 시스템을 제안한다. 감수지 부착 후 고도 및 속도 변화에 따른 농약 낙하균일도 측정 및 작물 성장조건 변화에 따른 수관내부 약제 침투율 측정 실험을 통해 제안하는 모델의 효과성을 보였다. 실험결과, 무인항공기의 높이가 지면과 가까울수록 작물에 고르게 살포되지만 안전이 고려된 2m이상이 높이와 평균 2m/s의 속도에서 가장 방제효과가 적합하였다. 제안하는 방제 시스템은 농업환경에서의 다양한 무인항공기 활용 기반 지능형 서비스 개발에 도움을 줄 것으로 기대한다.

• 약학회지
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• 제50권2호
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• pp.136-143
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• 2006

Roots of Scutellaria baicalensis have been used for fever remedy; diuresis, antiphlogistic. For the investigation of the active component from aerial parts of Scutellaria baicalensis, MeOH extracts from aerial parts of Scutellaria baicalensis were suspended with $H_2O$, and partitioned by $CHCl_3$. In order to investigate the efficacy of antioxidative activity the activity guided fraction and isolation of physiologically active substance were peformed. Its $H_2O,\;30\%,\;60\%$ MeOH and MeOH fractions were examined on antioxidative activity using DPPH method and TBARS assay; It was revealed that $30\%\;and\;60\%$ MeOH fractions have significant anti-oxidative activity. its fractions testing type I allergy, compound 48/80 induced systemic anaphylaxis was applied. As a result, compared with reference (cromolygate), these fraction significantly inhibited systemic anaphylaxis by $71\%\;and\;57\%$, respectively. From $30\%,\;60\%$ MeOH fraction, five compounds were isolated and elucidated apigenin 6-C-${\alpha}$-L-arabinopyranosyl-8-C-${\beta}$-D-glucopyranoside (isoschaftside, I), scutellarein 7-O-${\beta}$-D-glucuronopyranoside (scutellarin, II), apigenin 7-O- ${\beta}$-D-glucuronopyranoside (III), isoscutellarein 8-O-${\beta}$-D-glucuronopyranoside (IV), kaempferol 3-O-${\beta}$-D-glucopyranoside (V) through their physicochemical data and spectroscopic methods. We measured radical scavenging activity with DPPH method and anti-lipid peroxidative efficacy on human LDL with TBARS assay. [$I] showed antioxidant activities in order. Type I allergy compound 48/80 induced systemic anaphylaxis was applied. $[V inhibited systemic anaphylaxis in order.

• Journal of Biosystems Engineering
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• 제33권2호
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• pp.94-100
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• 2008

Present chemical application method using a power sprayer has been labor intensive, costly and ineffective. Therefore, a small agricultural unmanned helicopter was suggested to replace the conventional spray system. In this study, conceptual design for developing the helicopter and a consequential prototype were reported. The overall conceptual design was initiated by deciding the type of agricultural helicopter, as the single rotor helicopter with a tail system. As the first step of the designing, an air-cooled, 2-stroke engine was selected and a prototype transmission was designed by determining the rotating speed of main rotor shaft. A 'pusher' type tail rotor system was adapted to balance the reaction torque and reduce the power use. The tail boom length was designed to avoid the rotating trajectory of the main rotor. The RF console consisted of the engine control, attitude control, and emergency control modules. Assembling the prototype concluded the mechanical development of the agricultural helicopter.

• International Journal of Aeronautical and Space Sciences
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• 제11권3호
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• pp.167-174
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• 2010

The design, dynamics, and control allocation of tri-rotor unmanned aerial vehicles (UAVs) are introduced in this paper. A trirotor UAV has three rotor axes that are equidistant from its center of gravity. Two designs of tri-rotor UAV are introduced in this paper. The single tri-rotor UAV has a servo-motor that is installed on one of the three rotors, which enables rapid control of its motion and its various attitude changes-unlike a quad-rotor UAV that depends only on the angular velocities of four rotors for control. The other design is called 'coaxial tri-rotor UAV,' which has two rotors installed on each rotor axis. Since the tri-rotor type of UAV has the yawing problem induced from an unpaired rotor's reaction torque, it is necessary to derive accurate dynamic and design control logic for both single and coaxial tri-rotors. For that reason, a control strategy is proposed for each type of tri-rotor, and nonlinear simulations of the altitude, Euler angle, and angular velocity responses are conducted by using a classical proportional-integral-derivative controller. Simulation results show that the proposed control strategies are appropriate for the control of single and coaxial tri-rotor UAVs.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.580-585
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• 2005

A QRT(Quad-Rotor Type) hovering robot system is developed for quick detection and observation of the circumstances under calamity environment such as indoor fire spots. The UAV(Unmanned Aerial Vehicle) is equipped with four propellers driven by each electric motor, an embedded controller using a DSP, INS(Inertial Navigation System) using 3-axis rate gyros, a CCD camera with wireless communication transmitter for observation, and an ultrasonic range sensor for height control. The developed hovering robot shows stable flying performances under the adoption of RIC(Robust Internal-loop Compensator) based disturbance compensation and the vision based localization method. The UAV can also avoid obstacles using eight IR and four ultrasonic range sensors. The VTOL(Vertical Take-Off and Landing) flying object flies into indoor fire spots and sends the images captured by the CCD camera to the operator. This kind of small-sized UAV can be widely used in various calamity observation fields without danger of human beings under harmful environment.

• 한국항공우주학회지
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• 제34권8호
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• pp.63-70
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• 2006

초소형 비행체는 초소형, 초경량이기 때문에 매우 작고 가벼운 MEMS형 센서만이 초소형 비행체 자동 비행 장치에 적용될 수 있다. 본 논문에서는 이러한 MEMS 형 관성센서의 항법 성능을 향상시키기 위해 가속도계와 자이로를 혼합하는 알고리즘으로 자세 비교 보상을 이용한 혼합 방법을 제시하고 기존의 퍼지 추정을 이용한 혼합 방법과 시뮬레이션을 통해 성능을 비교한다. 이를 통하여 자세 비교 보상 방법을 이용한 혼합 방법이 기존의 퍼지를 기반으로 하는 혼합 방법보다 초소형 비행체 자세 추정에 보다 더 우수한 성능을 가짐을 보인다.

• 한국측량학회지
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• 제16권2호
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• pp.195-202
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• 1998

본 연구에서는 GPS 위성의 다양한 관측치를 이용한 GPS 항공삼각측량의 카메라 노출중심좌표 분석을 통해 관측치 종류별 활용 가능성을 연구하였다. 3차원 등각변환 방식을 통한 모델조정으로 획득한 동적 DGPS 카메라 노출중심좌표를 재래식 모델조정에 의해 결정된 카메라 노출중심좌표와 비교하여 각각의 정밀도 및 오차를 분석하였다. C/A코드 관측치의 경우, 카메라 노출중심좌표가 표준편차 $\pm{2m}$의 범위 내에서 결정되었고, L1 반송파 관측치는 $\pm{14cm}$ 이내, L1/L2 반송파 관측치는 $\pm{10cm}$ 이내로 결정되었다. 따라서 번들블럭조정 후 발생될 수 있는 카메라 노출중심좌표의 정확도를 미리 예측할 수 있었다.

• 한국수소및신에너지학회논문집
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• 제22권6호
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• pp.819-826
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• 2011

The proton exchange membrane fuel cell (PEMFC) is regarded as the most promising alternative power sources for unmanned aerial vehicle (UAV) due to its high energy density and silent operation. Since there are many load changes during UAV flight, thermal management is one of the important factor for the performance of PEMFC. In order to reduce the UAV weight for the stable operation of UAV, thermal management system (TMS) studied in this work does not use the fan but use the air flowing into UAV by UAV flight. In order to develop the passive type heat exchanger (HEX) for 1kW PEMFC, four types of HEXs are fabricated and their cooling performances are compared. The parametric study on the cooling performance of HEXs has performed with the variation of operating parameters such as mass flow rates and inlet temperature of air and coolant. Type 4 has the best performance in every case. This study can be helpful to achieve the optimal design of HEX for PEMFC powered UAV.

• 생약학회지
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• 제29권4호
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• pp.338-346
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• 1998

In order to elucidate the relationship between anti-HIV-1 enzyme activity and inhibition of HIV-1 replication by natural sources, extracts from some plants using the foods and oriental medicines were tested for inhibitory effects on the viral replication, reverse transcriptase (RT), protease and ${\alpha}-glucosidase$. In the anti-RT test, water extracts of Ficus carica (leaf), Houttuynia cordata (aerial part) and Ixeris tamagawaensis (aerial part) showed more than 79% inhitibion at a concentration of $100\;{\mu}g/ml$. The protease and ${\alpha}-glucosidase-inhibiting$ samples in the screening were water extract of Syringa dilatata (leaf) and methanol extract of Hibiscus syriacus (leaf and stem), which showed more than 40% inhibition at a concentration of $100\;{\mu}g/ml$. In the primary anti-HIV-1 test, water extracts of Equisetum arvense (aerial part), Hibiscus syriacus (leaf), Ixeris tamagawaensis (aerial part) and Pueraira thunbergiana (leaf) showed the potent inhibition against HIV-1 induced cytopathic effects.