• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.9
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• pp.833-841
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• 2016

The 200 W electrically powered unmanned aerial vehicle, which is studied in this research, uses solar cells, a fuel cell and batteries as the main power source simultaneously. The output of each power source performs power control for each power source by the active power control method so that an adequate capacity of the battery could be maintained while limiting the maximum output of the fuel cell. The output variation for each power source under the active power control method was identified through an integrated ground test. In addition, the effect of limiting the maximum output of the fuel cell on the output variation of the entire system was experimentally identified, and it was confirmed that the adequate maximum output value of the fuel cell for preventing the overdischarge of six series-connected, small size batteries for fuel cell systems is 150 W.

• Journal of Practical Engineering Education
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• v.9 no.1
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• pp.15-21
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• 2017

In order to satisfy the graduation requirements, the graduation work should be presented as an engineering dissertation system of the produced work and an outline of the procedure made by the major unit in accordance with the graduation thesis submission rules, and suggests necessary matters for improvement. The design content relates to a small unmanned aerial vehicle configuration for detecting personnel or objects in a disaster area. It is equipped with an infrared sensor and a GPS in the drone, the drone is control by using Blutooth communications. The drones detect the target and use the GPS to determine the location. As a result of the experiment, it was possible to detect the structure object within the range of 3~4 m, confirm the transmission of the position value in real time, and increase the communication distance by using RF communication.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.5
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• pp.326-334
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• 2019

Development of Small UAV using HILS (Hardware In the Loop Simulation) can be effectively used to improve the reliability of UAV (Unmanned Aerial Vehicle) while reducing cost and time. It is also possible to reduce the damage to people or property by simulating the malfunction of the Flight Control Computer (FCC) that may occur during the actual flight. For applying such HILS, a real-time simulation environment capable of providing an environment similar to an actual flight condition is required. In this paper, we constructed a real - time HILS environment for Small UAV using 6 D.O.F motion table. In order to link the 6 D.O.F motion table developed in the previous research with the HILS environment in real time, the motion algorithm was changed from the position control method to the velocity control method. Also, we implemented modeling of inverse kinematics model for command transmission in Matlab $Simulink^{(R)}$ and verified the action of motion table according to the simulation model.

• Journal of Ginseng Research
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• v.45 no.4
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• pp.527-534
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• 2021

Background: Phenological studies are a prerequisite for accomplishing higher productivity and better crop quality in cultivated plants. However, there are no phenological studies on Panax ginseng that improve its production yield. This study aims to redefine the phenological growth stages of P. ginseng based on the existing Biologische Bundesanstalt, Bundessortenamt und Chemische Industrie (BBCH) scale and proposes a disease control reference. Methods: This study was conducted at the Korea Ginseng Corporation Experiment Station in Gyeonggi province, South Korea. Phenological observations were performed once weekly or twice monthly, based on the developmental stages. The existing BBCH scale with a three-digit code was used to redefine and update P. ginseng's phenological growth codes. Results: The phenological description is divided into eight principal growth stages: three for vegetative growth (perennating bud, aerial shoot, and root development), four for reproductive growth (reproductive organ development, flowering, fruit development, and fruit maturation), and one for senescence according to the extended BBCH scale. A total of 58 secondary growth stages were described within the eight principal growth stages. Under each secondary growth stage, four mesostages are also taken into account, which contains the distinct patterns of the phenological characteristics in ginseng varieties and the process of transplanting seedlings. A practical management program for disease control was also proposed by using the BBCH code and the phenological data proposed in this work. Conclusion: The study introduces an extended BBCH scale for the phenological research of P. ginseng.

• The Journal of the Convergence on Culture Technology
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• v.9 no.2
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• pp.575-580
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• 2023

This study was prevent the decrease in crop output by insect pests and spraying by application uniformity. A flight level 4 m height and 4-5 m/sec. speed are difficult to maintain with a agricultural drone for aerial application, which has been affected by the methods or environmental factors, such as changes in the wind. Therefore, which can allow a controlled application width and spray rate automatically and verified experimentally using drone. The sprayed particles began to decrease from about 3.75 m on the left and right sides of the spray nozzle. According to the number of particles, the effective spraying width was observed to be about 7.5 m, and it was verified that the proposed spraying system was effective in uniform control system.

• Journal of Ginseng Culture
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• v.6
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• pp.51-79
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• 2024

In the 1970s and 1980s, during the nascent phase of ginseng disease research, efforts concentrated on isolating and identifying pathogens. Subsequently, their physiological ecology and pathogenesis characteristics were scrutinized. This led to the establishment of a comprehensive control approach for safeguarding major aerial part diseases like Alternaria blight, anthracnose, and Phytophthora blight, along with underground part diseases such as Rhizoctonia seedling damping-off, Pythium seedling damping-off, and Sclerotinia white rot. In the 1980s, the sunshade was changed from traditional rice straw to polyethylene (PE) net. From 1987 to 1989, focused research aimed at enhancing disease control methods. Notably, the introduction of a four-layer woven P.E. light-shading net minimized rainwater leakage, curbing Alternaria blight occurrence. Since 1990, identification of the bacterial soft stem rot pathogen facilitated the establishment of a flower stem removal method to mitigate outbreaks. Concurrently, efforts were directed towards identifying root rot pathogens causing continuous crop failure, employing soil fumigation and filling methods for sustainable crop land use. In 2000, adapting to rapid climate changes became imperative, prompting modifications and supplements to control methods. New approaches were devised, including a crop protection agent method for Alternaria stem blight triggered by excessive rainfall during sprouting and a control method for gray mold disease. A comprehensive plan to enhance control methods for Rhizoctonia seedling damping-off and Rhizoctonia damping-off was also devised. Over the past 50 years, the initial emphasis was on understanding the causes and control of ginseng diseases, followed by refining established control methods. Drawing on these findings, future ginseng cultivation and disease control methods should be innovatively developed to proactively address evolving factors such as climate fluctuations, diminishing cultivation areas, escalating labor costs, and heightened consumer safety awareness.

• Economic and Environmental Geology
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• v.52 no.2
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• pp.169-188
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• 2019

This study was carried out unmanned aerial photography and terrestrial laser scanning to establish digital database on original wall of Gyejoksanseong fortress, and measured ground control points for continuity of the monitoring. It also performed precise examination with the naked eye, unmanned aerial photogrammetry, endoscopy, total station and handy measurement to examine the structural stability of the original walls. The ground control points were considered as a point where visual field can be secured, 3 points were selected around each of the south and north walls. For the right side of the south original wall, aerial photogrammetry was conducted using drones and a deviation analysis of 3-dimensional digital models was performed for short-term monitoring. As a result, the two original walls were almost matched in range within 5mm, and no difference indicating displacement of stones was found, except for partial deviation. Regular monitoring of the areas with structural deformation such as bulging, weak and fracture zone by precisely examining with the naked eye and using high-resolution photo data revealed no distinct change. The inner foundation observed through endoscopy found out that filling stones of the original walls were still remained, while most filling soil was lost. As a result of measuring the total station focusing around the points with structural deformation on the original walls, the maximum displacements of the north and south walls were somewhat high with 6.6mm and 3.8mm, respectively, while the final displacements were relatively stable at below 2.9mm and 1.4mm, respectively. Handy measurement also did not reveal clear structural deformation with displacements below 0.82mm at all points. Even though the results of displacement monitoring on the original walls are stable, it is hard to secure structural stability due to the characteristics of ramparts where sudden brittle fracture occurs. Therefore, it is necessary to conduct conservational scientific diagnosis, precise monitoring, and structural analysis based on the 3-dimensional figuration information obtained in this research.

• Composites Research
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• v.36 no.3
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• pp.211-216
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• 2023

When designing ships and aircraft structures, it is important to design them to satisfy weight reduction and strength. Currently, studies related to topology optimization using 3D printed composite materials are being actively conducted to satisfy the weight reduction and strength of the structure. In this study, structural analysis was performed to analyze the applicability of 3D printed composite materials to the flight control surface, one of the parts of an aircraft or unmanned aerial vehicle. The optimal topology shape of the flight control surface for the bending load was analyzed by considering three types (hexagonal, rectangular, triangular) of the topology shape of the flight control surface. In addition, the bending strength of the flight control surface was analyzed when four types of reinforcing materials (carbon fiber, glass fiber, high-strength high-temperature glass fiber, and kevlar) of the 3D printed composite material were applied. As a result of comparing the three-point bending test results with the finite element method results, it was confirmed that the flight control surface with hexagonal topology shape made of carbon fiber and Kevlar had excellent performance. And it is judged that the 3D printed composite can be sufficiently applied to the flight control surface.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2004.04a
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• pp.15-26
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• 2004

The calibration for systematic error in LiDAR is crucial for the accuracy of airborne laser scanning. The main error is the misalignment of platforms between INS(Inertial Navigation System) and Laser scanner For planimetrical calibration of LiDAR, the building is good feature which has great changes in height and continuous flat area in the top. The planimetry error(pitch, roll) is corrected by adjustment of height which is calculated from comparing ground control points(GCP) of building to laser scanning data. We can know scale correction of laser range by the comparison of LiDAR data and GCP is arranged at the end of scan angle where maximize the height error. The area for scale calibration have to be large flat and have almost same elevation. At 1000m for average flying height, The Accuracy of laser scanning data using LiDAR is within 110cm in height and ${\pm}$50cm in planmetry so we can use laser scanning data for generating 3D terrain surface, expecically digital surface model(DSM) which is difficult to measure by aerial photogrammetry in forest, coast, urban area of high buildings

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.244-245
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• 2008

본 논문은 관성센서를 이용한 무인 항공체의 자세 제어에 관한 연구를 다루었다. 항공계의 종류는 크게 고정익기와 회선익기로 나뉘는데 본 연구에서는 회전익기의 형태를 가진 Quarter Vehicle을 사통하였다. Quarter Vehicle은 4개의 프로펠러에 의한 양력과 회전 반발력으로 비행을 한다. 이때의 양력은 수평면에 대해 수직으로 추력을 발생시키므로 다른 비행체보다 불안정하며 이를 안정하게 제어하기 위해 관성 센서를 적용하여 균형을 유지한다. 본 연구에서는 관성센서를 이용하여 UAV의 자세와 균형을 안정적으로 유지하여 안정적인 비행이 가능하도록 하였다. 또한 상호 의존적인 항법 시스템으로 환경변화에 영향을 받지 않으며, 정확한 위치정보를 제공하는 GPS를 사용하여 3개 이상의 위성으로부터 정보를 받아 좌표를 계산하고 위치, 속도 및 방향을 결정하여 자율 비행이 가능하도록 설계하였다. 본 논문에서는 Quarter Vehicle의 구조와 이론적 배경을 통한 설계, 그리고 관성센서와 GPS의 적용을 위한 방법을 제시 한다.