• Journal of the KSME
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• v.51 no.3
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• pp.48-52
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• 2011

• Water for future
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• v.49 no.6
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• pp.8-15
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• 2016

• Journal of Biosystems Engineering
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• v.20 no.3
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• pp.226-235
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• 1995

An unmanned speed sprayer was developed using a remote control and an inductive cable guidance systems to protect operators and environment from hazardous pesticides. The sprayer consists of a remote control system, an induction system, obstacle detectors, control actuators and an one-chip microcomputer. The sprayer can be operated by the induction guidance and/or remote control. The following summarize characteristics of the developed speed sprayer. 1) Both the remote control and the induction guidance operation were possible with the developed speed sprayer. 2) Sixteen functions of the forwarding, backing, halting, steering, 3-way valve for nozzles and fan operating etc. were utilized on the remote control system. 3) It was concluded that the DTMF method, having less transmitting error, performed better than the FSK method for an agricultural remote controller. A radio station may be necessary. 4) The digital inductive guidance system, consisting of five low-impedance detection coils and a window comparator circuit, performed better than the analog detecting system, guiding route using inductive voltage differential from tow detection coils.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.6
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• pp.488-496
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• 2015

This paper proposes a framework to determine the routes of multiple unmanned aerial vehicles (UAVs) to conduct multiple tasks in different locations considering the survivability of the vehicles. The routing problem can be formulated as the vehicle routing problem (VRP) with different cost matrices representing the trade-off between the safety of the UAVs and the mission completion time. The threat level for a UAV at a certain location was modeled considering the detection probability and the shoot-down probability. The minimal-cost path connecting two locations considering the threat level and the flight distance was obtained using the Dijkstra algorithm in hexagonal cells. A case study for determining the optimal routes for a persistent multi-UAVs surveillance and reconnaissance missions given multiple enemy bases was conducted and its results were discussed.

• Journal of the Korea Convergence Society
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• v.8 no.4
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• pp.9-18
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• 2017

UAVs began to be actively applied to so-called 3D jobs, including the autonomous exploration, investigation, mapping, search and rescue, etc. since the mid-2000s. With this global trend, having a precise controllability of the UAV will certainly revolutionize the life of the modern human in the aspect of tremendous applications of the UAV. In the first part, a simplified dynamic model of the UAV identified using system identification techniques is compared with the previously built time-discrete linear model. In the second part, the three parameters of the dynamic model are estimated using the batch and RLS methods. Angular acceleration data of the quadrotor UAV at the hovering maneuver are analyzed and shown to be converging at all time. Also, according to the quadrotor flight data from both experiments and MATLAB simulations, the batch estimation method turns out to be more accurate than the RLS estimation method based on the comparison of final parameter values.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.32 no.5
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• pp.737-750
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• 2022

The demands of Unmanned Aerial Vehicles (UAVs) are growing very rapidly with the era of the 4th industrial revolution. As the technology of the UAV improved with the development of artificial intelligence and semiconductor technology, it began to be used in various civilian fields such as hobbies, bridge inspections, etc from being used for special purposes such as military use. MAVLink (Macro Air Vehicle Link), which started as an open source project, is the most widely used communication protocol between UAV and ground control station. However, MAVLink does not include any security features such as encryption/decryption mechanism, so it is vulnerable to various security threats. Therefore, in this study, the block cipher is implemented in UAV to ensure confidentiality, and the results of the encryption and decryption performance evaluation in the UAV according to various implementation methods are analyzed. In addition, we proposed the security requirements in accordance with Common Criteria, which is an international recognized ISO standard.

• Journal of Aerospace System Engineering
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• v.18 no.3
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• pp.48-55
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• 2024

In recent years, as the commercialization of unmanned aerial vehicles (UAVs) has been actively promoted, much attention has been focused on developing a technology to ensure the safety of UAVs. In general, the UAV has the potential to enter an uncontrollable state caused by sudden maneuvers, disturbances, and pilot error. To prevent entering an uncontrolled situation, it is essential to predict the flight state of the UAV. In this paper, we propose a flight state prediction technique based on an improved CNN-LSTM hybrid mode to enhance the flight state prediction performance. Simulation results show that the proposed prediction technique offers better state prediction performance than the existing prediction technique, and can be operated in real-time in an on-board environment.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.11
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• pp.33-40
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• 2005

The reliability of flight control system(FCS) for Unmanned Air Vehicle(UAV) is underestimated because of the design restrictions such as small size, low cost and light weight. However because the failure of FCS may cause the loss of aircraft, the reliability of FCS must be analysed and validated whether it meet the reliability requirements in design phase.In this paper the failure rate of subsystems was divided with its function based on the design experience of FCS. The redundancy models which satisfy the system reliability requirements were suggested. These results may be utilized in the hardware design of FCS.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2012.05a
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• pp.153-156
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• 2012

The optimization and integration of a fuel cell were performed to improve the performance and reliability of the fuel cell in this paper. To improve the performance of the PEMFC, current and voltage of the fuel cell were measured using an electrical load, and the results was compared and analyzed with the data of a commercial fuel cell. Based on the above results, a controller for a fuel cell UAV applications was designed, and the fuel cell control algorithm was developed to optimize the performance of the fuel cell UAV.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.139-140
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• 2022

자율운항선박은 사람이 없다는 전제를 두고 개발되고 있지만, 완벽한 자율운항이 되기까지는 많은 시간이 필요할 것이다. 이러한 경우, 발생 가능한 모든 경우의 수를 고려하여 시나리오를 구축하는 것이 중요한데, 자율운항 선박에 대한 사고는 아직 발생한 바가 없기 때문에 시나리오를 구축하는 것은 어렵다. 이에, 본 연구에서는 기존 조사된 해양사고 사고·사례를 통해 아직 발생한적 없지만 발생가능 확률이 높다고 생각되는 사고 시나리오를 구축하여야 한다. 이러한 시나리오가 있다면 자율운항선박 사이의 사고 등을 확률적으로 추정할 수 있다. 한편, 해양사고의 종류는 다양하나, 본 연구에서는 위험유해물질(HNS)을 적재된 자율운항선박으로 제한하며, 최종 목표는 자율운항의 기초 단계로, 무인화 선박에서 발생 가능한 사고경로를 예측하여 화학 사고를 예방하는 것이다. 본 연구의 목적으로는 기존의 해상 화학사고 원인을 분석하여 ETA기법을 적용한 자율운항 선박에서 발생 가능한 사고 시나리오를 구축하는 것이다. 연구방법으로는 자율운항 시 발생할 수 있는 가상경로를 화학반응식으로 식별하고, ETA기법을 이용하여 화학사고가지분석(CATA, Chemical Accident Tree Analysis)모델을 구축할 예정이다.