• The Journal of the Korea institute of electronic communication sciences
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• v.14 no.5
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• pp.901-906
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• 2019

UAV (Unmanned Aerial Vehicle) is widely used in various areas such as civil and military applications including entertainment industries. Among them, UAV based communication system is also one of the important application areas. Relays have been received much attention in communication system due to its benefits of performance enhancement and coverage extension. In this paper, we investigate UAVs as relays especially focusing on physical layer. First, we introduce the research on UAV application for the relays, then the basic performance of relay networks in dual-hop communication system is analyzed by adopting decode-and-forward (DF) relaying protocol. The performance is represented using symbol error rate (SER) and UAV channels are applied by assuming asymmetric environments. Based on the performance analysis, we discuss performance enhancement issues by considering physical layer.

• Computers and Concrete
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• v.33 no.4
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• pp.425-443
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• 2024

Floods are among the most common natural hazards in urban areas. To mitigate the problems caused by flooding, unstructured data such as images and videos collected from closed circuit televisions (CCTVs) or unmanned aerial vehicles (UAVs) have been examined for flood management (FM). Many computer vision (CV) techniques have been widely adopted to analyze imagery data. Although some papers have reviewed recent CV approaches that utilize UAV images or remote sensing data, less effort has been devoted to studies that have focused on CCTV data. In addition, few studies have distinguished between the main research objectives of CV techniques (e.g., flood depth and flooded area) for a comprehensive understanding of the current status and trends of CV applications for each FM research topic. Thus, this paper provides a comprehensive review of the literature that proposes CV techniques for aspects of FM using ground camera (e.g., CCTV) data. Research topics are classified into four categories: flood depth, flood detection, flooded area, and surface water velocity. These application areas are subdivided into three types: urban, river and stream, and experimental. The adopted CV techniques are summarized for each research topic and application area. The primary goal of this review is to provide guidance for researchers who plan to design a CV model for specific purposes such as flood-depth estimation. Researchers should be able to draw on this review to construct an appropriate CV model for any FM purpose.

• Journal of Ginseng Research
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• v.28 no.4
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• pp.201-206
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• 2004

This experiment was conducted to determine the economic application method of Yakto among 6 application method : amount of Yakto application $3\;plot(70\;l,\;25.5\;l,\;13,3\;l/kan;\;180cm{\times}90cm),$ and added side dressing(3 l/kan) each plot. The reduced amoumt of Yakto application(25.5 l, 13.3 l/kan) were lower the contents of inorganic nitrogen, $P_{2}O_{5},\;K,\;Ca$ and Mg, but similar pH in bed soil compared with standard Yakto application(70 l/kan). Side dressing applicated on 29 May increased the contents of inorganic nitrogen, $P_{2}O_{5},\;K,\;Ca,\;Mg$ and salt concentration in bed soil compared with non­side dressing in each Yakto application plot(70 l, 25.5 l, 13,3 l/kan). The reduced amoumt of Yakto application(25.5 l/kan) added side dressing(3 l/kan) were similar the contents of inorganic nitrogen, K, Mg and salt but lower $P_{2}O_{5}$ and Ca in bed soil compared with standard Yakto application(70 l/kan) in June. The reduced amoumt of Yakto application(25,5 l/Kan) added side dressing(3 l/kan) was similar the contents of P, K, Ca and Mg but lower N in leaves compared with standard Yakto application(70 l/kan). The reduced amoumt of Yakto application(25.5 l/kan) added side dressing(3 l/kan) was shorter stem length, and higher $5{\%}$ chlorosis of leaf tip, but similar emergence ratio, survival ratio, leaf senescence ratio, chlorophyll, stem diameter and leaf area compared with standard Yakto application(70 l/kan). These suggested that 25.5 l Yakto application added side dressing(3 l/kan) per kan might be possible economical application method of Yakto.

• The Korean Journal of Pesticide Science
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• v.20 no.3
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• pp.181-188
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• 2016

BtPlus is a group of biopesticides that are made of Bacillus thuringiensis and immunosuppressant. A new BtPlus that exhibits high insecticidal activity against mosquito larvae has been investigated in control efficacy in field conditions and its environmental safety against aquatic system. This study assessed the control efficacy of BtPlus against mosquito larvae with two different application methods. In aerial spraying application (100 mL per $3.3m^2$), BtPlus was effective at 50% or above formulation concentrations to control mosquito larvae. For a direct application to aqueous mosquito habitat, a semi-field mimicking paddy rice field was constructed. In this condition, BtPlus showed 80% and 100% control efficacies at 0.1% and 0.2% concentrations, respectively. BtPlus also showed 40% mortality against adults at 0.1% concentration in 10% sugar bait. However, its control efficacies against adults were much less than against larvae. Safety assessment of BtPlus against ecosystem was evaluated using young carp (Cyprinus carpio), a water flea (Daphnia magna), and a honey bee (Apis mellifera). BtPlus did not give any adverse effects on these nontarget organisms. Based on these results, BtPlus can be applied to control mosquitoes by direct aqueous application to paddy rice field.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.28 no.6
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• pp.579-586
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• 2010

Due to the recent development of measuring technology and 3D programs, it has become possible to obtain various spatial data. This study utilizes the 2-dimensional data and 3-dimensional data extraction technology based on the existing empirical and statistical DB. The data obtained from geospatial data technology are integrated with civil engineering BIM to conduct the modeling of the topography of the target region and select the optimum location condition by using the cut and fill balance of the volume of earth. The target area is the land around Tamjin River, Jangheong-gun, Jeolla-do. The 3-dimensional topology linked with 3-dimensional mapping technology by using the orth-image and aerial LiDAR that uses aerial photo of the target area is visualized with Civil3D of AutoDesk. By using Civil3D program, the Thanks to the recent development of measuring technology and 3D programs, target area is analyzed through visualization and related data can be obtained for analysis. The method of using civil engineering BIM enables to obtain various and accurate information about the target area which is helpful for addressing the issues risen from the existing methodology. In this regard, it aims at searching for the alternatives and provides suggestions to utilize the information.

• Applied Biological Chemistry
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• v.46 no.4
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• pp.376-379
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• 2003

The aerial parts of tile Garland (Chrysanthemum comnarium L.) were extracted in MeOH and solvent fractionated with EtOAc, n-BuOH and water, successively. EtOAc fractions gave three steroid compounds through application of silica gel column chromatographies. The chemical structures of the steroids were determined by the interpretation of several spectral data, including NMR and MS as $stigmast-5-en-3{\beta}-ol\;(1,\;{\beta}-sitosterol),\;stigmast-4-en-6{\beta}-ol-3-one$ (2), $stigmast-4-en-6{\alpha}-ol-3-one$ (3). Compounds 2 and 3 have been so far reported only in the aquatic plants, were isolated for the first time from the land plants.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.296-303
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• 2015

The concentration of solute in a $NaBH_4$ solution is limited due to the low solubility of $NaBO_2$. The performance of a hydrogen generation system was evaluated using various concentrations of $NaBH_4$ solution. First, a self-hydrolysis test and a hydrogen generation test for 30 min were performed. The composition of $NaBH_4$ solution was selected to be 1 wt% NaOH + 25 wt% $NaBH_4$+74wt% $H_2O$ by considering the amount of hydrogen loss, stability of hydrogen generation, $NaBO_2$ precipitation, conversion efficiency, and the purpose of its application. A hydrogen generation system for a 200 W fuel cell was evaluated for 3 h. Although hydrogen generation rate decreased with time due to $NaBO_2$ precipitation, hydrogen was produced for 3 h (conversion efficiency: 87.4%). The energy density of the 200 W fuel cell system was 263 Wh/kg. A small unmanned aerial vehicle with this fuel cell system can achieve 1.5 times longer flight time than one flying on batteries.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.4
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• pp.447-456
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• 2010

The application of a reliable motion simulator can contribute effectively in the evaluation of the performance of a vehicle platform in the development stage of a small unmanned aerial vehicle (UAV). Therefore, the research on a reliable motion simulator can accelerate the development of UAV and decrease the relevant cost. In this paper, the design factors considered in the preliminary design stage of a 6 degree-of freedom motion simulator are defined and the motion range of the simulator is described on the basis of these design factors. The length, acceleration, and the required thrust of actuators with respect to the motion simulator under development are also predicted. The motion range can be increased and a suitable actuator can be selected and produced by applying these results in the manufacturing process of the motion simulator. Thus, the reliability of the motion simulators can be achieved during the actual design operation of the UAV.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1217-1222
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• 2010

This paper describes the Model-Based Development(MBD) process behind the flight control software of a close-range unmanned aerial vehicle(KUS-9). An integrated development environment was created using a commercial tool(MATLAB $Simulink^{(R)}$), which was utilized to design models for linear/nonlinear simulation, flight control law, operational logic and HILS(Hardware In the Loop Simulation) system. Software requirements were validated through flight simulations and peer reviews during the design process, whereas the models were verified through the application of a DO-178B verification tool. The integrity of automatically generated C code was verified by using a separate S/W testing tool. The finished software product was embedded on two different types of hardware and real-time operating system(uC/OS-II, VxWorks) to perform HILS and flight tests. The key findings of this study are that MBD Technology enables the development of a reusable and an extensible software product and auto-code generation technology allows the production of a highly reliable flight control software under a compressed time schedule.

• Food Science and Biotechnology
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• v.18 no.1
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• pp.95-102
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• 2009

The aerial parts of garland (Chrysanthemum coronarium L.) were extracted in 80% aqueous methanol (MeOH) and the concentrated extract was then partitioned using ethyl acetate (EtOAc), n-butanol (n-BuOH), and $H_2O$, successively. EtOAc and n-BuOH fractions resulted in 4 glycerides with the application of octadecyl silica gel and silica gel column chromatography. The chemical structures of the glycerides were determined using several spectroscopic methods, including nuclear magnetic resonance (NMR) and mass spectrometry (MS) as (2S)-1-O-palmitoyl-sn-glycerol (1), (2S)-1-O-oleoyl-2-O-oleoyl- 3-O-$\beta$-D-galactopyranosyl-sn-glycerol (2), (2S)-1-O-palmitoyl-2-O-linoleoyl-3-O-phosphorouscholine-sn-glycerol (3), and (2S)-1-O-linolenoyl-2-O-palmitoyl-3-O-[$\alpha$-D-galactopyrasyl-($1{\rightarrow}6$)-$\beta$-D-galactopyranosyl]-sn-glycerol (4). The free fatty acids of these glycerides were determined with gas chromatography (GC)-MS analysis following alkaline hydrolysis and methylation. These glycerides demonstrated an inhibitory effect on acyl-CoA: cholesterol acyltransferase (ACAT, compound 1: $45.6{\pm}0.2%$ at $100{\mu}g/mL$), diacylglycerol acyltransferase (DGAT, compound 1: $59.1{\pm}0.1%$ at $25{\mu}g/mL$), farnesyl protein transferase (FPTase, compound 2: $98.0{\pm}0.1%$; compound 3: $55.2{\pm}0.1%$ at $100{\mu}g/mL$), and $\beta$-secretase ($IC_{50}$, compound 4: $2.6{\mu}g/mL$) activity. This paper is the first report on the isolation of these glycerides from garland and their inhibitory activity on ACAT, DGAT, FPTase, and $\beta$-secretase.