• Korean journal of applied entomology
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• v.59 no.2
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• pp.83-91
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• 2020

We assessed efficacy of spraying pesticides from an unmanned helicopter to control two insect species, Monochamus alternatus and M. saltuarius, which are vectors of pine wood nematodes. Control efficacy of thiacloprid FL (33×), acetamiprid ME (33×), and flupyradifurone SL (33×) was determined by placing caged insects in the canopy of pine trees (Pinus sp). Water-sensitive paper was used to record the spray pattern of pesticide droplets and the degree of coverage; furthermore, we investigated peripheral scattering due to spraying. The three pesticides showed > 96% control efficacy against the targeted vectors, and pesticide droplet spray patterns were similar. Peripheral scattering was observed up to 20 m in front and 10 m to the left, right, and behind the targeted area. The coverage index of all the directions at 5 and 10 m distance was 6-7 and 2, respectively.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.137-148
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• 2014

A multi-rotor is an autonomous flying robot with multiple rotors. Depending on the number of the rotors, multi-rotors are categorized as tri-, quad-, hexa-, and octo-rotor. Given their rapid maneuverability and vertical take-off and landing capabilities, multi-rotors can be used in various applications such as surveillance and reconnaissance in hostile urban areas surrounded by high-rise buildings. In this paper, the unified dynamic model of each tri-, quad-, hexa-, and octo-rotor are presented. Then, based on derived mathematical equations, the operation and control techniques of each multi-rotor are derived and analyzed. For verifying and validating the proposed models, operation and control technique simulations are carried out.

• Journal of Advanced Navigation Technology
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• v.25 no.4
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• pp.273-279
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• 2021

A flight control computer(FLCC) applied to an unmanned aerial vehicle(UAV) is a safety-critical item, and which is designed in a multiple structure to increase the reliability of operation by securing fault tolerance. These FLCC of multiple structure should be designed so that each independent processing/control components can perform the same operation at the same time. And for this reason, a synchronization algorithm for synchronizing the operation between FLCCs should be included in an operational flight program. In this paper, we propose a software design method for synchronization between dual FLCCs applied to UAVs. The proposed synchronization method is designed to synchronize using only the minimum hardware resources to reduce a failure rate. In addition, the proposed synchronization method is designed to minimized synchronization errors due to a timer operation by designing in consideration of operation characteristics of the hardware timer used for the synchronization.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.7
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• pp.479-487
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• 2022

This paper presents the control and guidance algorithm of a KAU-SPUAV(Korea Aerospace University - Solar Powered Unmanned Aerial Vehicle) which is designed and developed in Korea Aerospace University. Aerodynamic coefficients are calculated using the vortex-lattice method and applied to the aircraft's six degrees of freedom equation. In addition, the thrust and torque coefficients of the propeller are calculated using the blade element theory. An altitude controller using thrust was used for longitudinal control of KAU-SPUAV to glide efficiently when it comes across the upwind. Also describes wind estimation technic for considering wind effect during flight. Finally, introduce some guidance laws for endurance, mission and coping with strong headwinds and autonomous landing.

• Korean Journal of Remote Sensing
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• v.31 no.3
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• pp.215-226
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• 2015

Normally, aero photography using UAV uses about 430 MHz bandwidth radio frequency (RF) modem and navigates and remotely controls through the connection between UAV and ground control system. When using the exhausting method, it has communication range of 1-2 km with frequent cross line and since wireless communication sends information using radio wave as a carrier, it has 10 mW of signal strength limitation which gave restraints on life my distance communication. The purpose of research is to use communication technologies such as long-term evolution (LTE) of smart camera, Bluetooth, Wi-Fi and other communication modules and cameras that can transfer data to design and develop automatic shooting system that acquires images to UAV at the necessary locations. We conclude that the android based UAV filming and communication module system can not only film images with just one smart camera but also connects UAV system and ground control system together and also able to obtain real-time 3D location information and 3D position information using UAV system, GPS, a gyroscope, an accelerometer, and magnetic measuring sensor which will allow us to use real-time position of the UAV and correction work through aerial triangulation.

• Journal of Applied Biological Chemistry
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• v.60 no.2
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• pp.149-153
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• 2017

Contamination and growth of Trichoderma, a green mold, on the oak log and wooden chip or sawdust media can severely inhibit the growth of oak mushroom. Chemicals including pesticides and antibiotics are generally not allowed for the control of green mold disease during mushroom cultivation. In this study, bacterial pathogens causing blotch disease on the oyster mushrooms were isolated and their peptide toxins were purified for the control of green mold disease. Strains of Pseudomonas tolaasii secret various peptide toxins, tolaasin and its structural analogues, having antifungal activities. These peptides have shown no effects on the growth of oak mushrooms. When the peptide toxins were applied to the green mold, Trichoderma harzianum H1, they inhibited the growth of green molds. Among the 20 strains of peptide-forming P. tolaasii, strong, moderate, and weak antifungal activities were measured from 8, 5, and 7 strains, respectively. During oak mushroom cultivation, bacterial culture supernatants containing the peptide toxins were sprayed on the aerial mycelia of green molds grown on the surface of sawdust media. The culture supernatants were able to suppress the fungal growth of green molds while no effect was observed on the mushroom growth and production. They changed the color of molds from white aerial mycelium into yellowish dried scab, representing the powerful anti-fungal and sterilization activities of peptide toxins.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.4
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• pp.345-352
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• 2020

To preserve and restore tidal flats and prevent safety accidents, it is necessary to construct tidal flat topographic information including the exact location and shape of tidal creeks. In the tidal flats where the field surveying is difficult to apply, airborne LiDAR surveying can provide accurate terrain data for a wide area. On the other hand, we can economically obtain relatively high-resolution data from UAV (Unmanned Aerial Vehicle) surveying. In this study, we proposed the methodology to generate high-resolution topographic information of tidal flats effectively by integrating airborne LiDAR and UAV point clouds. For the purpose, automatic ICP (Iterative Closest Points) registration between two different datasets was conducted and tidal creeks were extracted by applying CSF (Cloth Simulation Filtering) algorithm. Then, we integrated high-density UAV data for tidal creeks and airborne LiDAR data for flat grounds. DEM (Digital Elevation Model) and tidal flat area and depth were generated from the integrated data to construct high-resolution topographic information for large-scale tidal flat map creation. As a result, UAV data was registered without GCP (Ground Control Point), and integrated data including detailed topographic information of tidal creeks with a relatively small data size was generated.

• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.1
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• pp.103-110
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• 2017

In Concentrated Animal Feeding Operations(CAFOs), emission of ammonia from stored manure contributes negatively on the wellness of livestock. In CAFOs facilities, indoor aerial ammonia concentration oftentime surpasses the critical level potentially harmful to livestock's immune system. Understandably, numerous researches to control aerial ammonia have been conducted in countries where CAFOs were practiced for many decades. Some innovative technologies, such as scrubber, bio-filter, and additives emerged, as a result. Among them, microbial additives became popular in Korea, due to an easiness of use and affordability. However, microbial additives still have some weaknesses. Their price is still high enough to discourage farmers who run a small scale farm and their effectiveness are still questioned by many users and researchers. In the present study, we found soluble carbohydrates, such as sugar, glucose, and molasses, when supplemented to pig slurry manure, can mitigate ammonia emission. To be more specific, pig manure slurry(120kg), stored in container(200L), was supplemented with sugar at 0.1%(w/w) and was, subsequently, monitored for pH and aerial ammonia for next 10 days. From this experiment, it was found that the sugar supplementation was effective in mitigating the aerial ammonia concentration (33% in average) when monitored daily. Also, the pH of manure slurry was maintained at relatively low level(8.2) in sugar-supplemented manure slurry while it was elevated to 8.5 in untreated slurry. Conclusively, the obtained data suggest that soluble carbohydrate can mitigate ammonia emission by acidifying manure slurry. Additionally, it can be suggested that soluble carbohydrates, such as sugar, glucose, and molasses, can be reasonable choices for animal farmers who have been looking for an alternative choice to replace expensive microbial additives.

• Journal of Mushroom
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• v.12 no.2
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• pp.132-137
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• 2014

Green mold disease caused by Trichoderma species has recently caused considerable damage to oyster mushroom industries in Korea. This disease Trichoderma, Penicillium, Aspergillus, such as in (genus) to be included in a disease caused by a species that collectively the largest incidence and damage is caused by the pathogen Trichoderma genus. T. longibrachiatum, Trichoderma koningii, Trichoderma virens, T. hazianum, T. atroviride, and T. pseudokoningii were detected on oyster mushroom beds and, of them, T. virens, T. hazianum, T. longibrachiatum was the most frequently detected. The knowledge concerning physiological and ecological properties of Trichoderma spp. was essential for their effective control. T. longibrachiatum hyphal growth is very fast, spore formation, and, particularly well-chlamydospore formation characteristics, and reviews are dark green discoloration. T. koningii, fast mycelial growth, aerial hyphae and spores in aerial hyphae formation is concentrated. T. virens, especially if the color change caused by spore-forming, slow, late in infection, the more severe the damage is discovered. T. hazianum fast mycelial growth, white aerial hyphae and late turns dark green. After spore formation hyphae glob of white pustules or tufts on the top of the formation. T. atroviride. aerial hyphae usually the mycelial growth and spore formation in the unlikely event of the formation and smells similar to the smell of coconut is that. Fast T. pseudokoningii mycelial growth, spore formation is formed around the inoculation site, discoloration of the medium color and well formed chlamydospores.

• The Korean Journal of Pesticide Science
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• v.16 no.4
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• pp.315-321
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• 2012

Fate of acetamiprid and imidacloprid aerially sprayed to control pine wood nematode (Bursaphelenchus xylophilus) were studied in a forest of Haman area. Acetamiprid 20% SL or imidacloprid 20% DC were diluted 100 times and applied two times as rate of 50 L/ha using an aircraft of Bell 206 L helicopter. Average acetamiprid deposits on forest floor ranged from 2 to 4% of standard aerial application rate. Following to the second application, acetamiprid deposits in the pine needle ranged 1.8~8.5 mg/kg and then gradually decreased to 1.2~2.1 mg/kg after 48 days. Deposits on the plant washed off by rainfall and reached to soil surface was ca. 17% of the application rate. All of acetamiprid on the ground resided in the forest floor covering the soil surface, where acetamiprid residues were decreased to a quarter at 48 days after the second application, but they were not detected in soil beneath it. And the only low level of acetamiprid residues, 0.0003 mg/L, was detected in the reservoir nearby the experimental forest on the day of aerial application. The acetamiprid detection was presumably due to spray drift. And average imidacloprid deposits on forest floor ranged from 1 to 3% of standard aerial application rate. Following to the second application, imidacloprid deposits in the pine needle analysed very low concentration of 0.1 mg/kg, but the amount of imidacloprid in wash-off in standard and two-fold treatment were ca. 8% and 4% of the application rate, respectively. Most of imidacloprid on the ground also resided in the forest floor, where imidacloprid residues were decreased to a twentieth at 111 days after the second application, and they were detected below 0.5% of the application rate in sol beneath it. And the low level of imidacloprid, 0.0003~0.0017 mg/L, were detected in the streams in the experimental forest. It was not to the level of contamination concerns.