• Journal of Sensor Science and Technology
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• v.33 no.5
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• pp.391-398
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• 2024

Accurate positioning is essential for unmanned underwater vehicle (UUV) operations, particularly for long-term survey missions. To reduce the inherent positioning errors from the inertial navigation systems of UUVs, or dead reckoning, underwater terrain observations from sonar sensors are typically exploited. Within the framework of pose-graph optimization, we can generate submaps of the seafloor and use them to add loop-closure constraints to the pose graph by determining the best match between the submaps. However, this approach results in error accumulation in long-term operations because the quality of local submaps depends on the dead reckoning. Hence, we can adopt external acoustic positioning systems, such as an ultrashort baseline (USBL), to add global constraints to the existing pose graph. We assume that the acoustic transponder is installed on a UUV and that the acoustic transceiver is equipped in an unmanned surface vehicle trailing the UUV to maintain an acoustic connection between the vehicles. We simulate the terrain and USBL measurements as well as evaluate the performance of the UUV's pose estimation via online pose-graph optimization.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.2
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• pp.367-418
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• 2018

Just as safety is the most important thing in aviation, safety is the most important in the operation of unmanned aircraft (RPA), and safety operation is the most important in the legal responsibility of the operator of the unmanned aircraft. In this thesis, the legal responsibility of the operator of the unmanned aircraft, focusing on the responsibility of the operator of the unmanned aircraft, was discussed in depth with the issue of insurance, which compensates for damages in the event of an accident First of all, the legal responsibility of the operator of the unmanned aircraft was reviewed for the most basic : definition, scope and qualification of the operator of the unmanned aircraft, and the liability of the operator of the Convention On International Civil Aviation, the ICAO Annex, the RPAS Manual, the Rome Convention, other major international treaties and Domestic law such as the Aviation Safety Act. The ICAO requires that unmanned aircraft be operated in such a manner as to minimize hazards to persons, property or other aircraft as a major principle of the operation of unmanned aircraft, which is ultimately equivalent to manned aircraft Considering that most accidents involving unmanned aircrafts fall to the ground, causing damage to third parties' lives or property, this thesis focused on the responsibility of operators under the international treaty, and the responsibility of third parties for air transport by Domestic Commercial Act, as well as the liability for compensation. In relation to the Rome Convention, the Rome Convention 1952 detailed the responsibilities of the operator. Although it has yet to come into effect regarding liability, some EU countries are following the limit of responsibility under the Rome Convention 2009. Korea has yet to sign any Rome Convention, but Commercial Act Part VI Carriage by Air is modeled on the Rome Convention 1978 in terms of compensation. This thesis also looked at security-related responsibilities and the responsibility for privacy infringement. which are most problematic due to the legal responsibilities of operating unmanned aircraft. Concerning insurance, this thesis looked at the trends of mandatory aviation insurance coverage around the world and the corresponding regulatory status of major countries to see the applicability of unmanned aircraft. It also looked at the current clauses of the Domestic Aviation Business Act that make insurance mandatory, and the ultra-light flight equipment insurance policy and problems. In sum, the operator of an unmanned aircraft will be legally responsible for operating the unmanned aircraft safely so that it does not pose a risk to people, property or other aircraft, and there will be adequate compensation in the event of an accident, and legal systems such as insurance systems should be prepared to do so.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.12 no.6
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• pp.612-618
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• 2019

In the unmanned vehicle industry, the market is exploding due to the rapid development of public and private demands along with the technological development of the 4th Industrial Revolution. In addition, unmanned mobiles are being used for communication services. In this paper, we analyzed the communication performance of unmanned aerial vehicle according to the characteristics of Doppler frequency. The Doppler frequency was calculated using the geometric model of the unmanned aerial vehicle, and the Doppler frequency of 10km, 30km, 300km, 1000km per hour and the BER performance by AWGN were measured by considering the unmanned high speed unmanned vehicle based on the position of the controller. The Doppler frequency model uses a Dent model and adds additive white Gaussian noise (AWGN) to check the bit errors of the transmitter and receiver. Low speed unmanned vehicles generally exhibited a BER performance of 0.2, while high speed unmanned vehicles generally exhibited a BER performance of 0.06. As the frequency band increases at the same speed, the BER performance increases, and when the speed increases in the same frequency band, the BER performance decreases. This is confirmed by the simulation results to predict theoretically predictable BER performance. In the frequency bands of 2.6 GHz, 5 GHz, and 28 GHz, the BER characteristics by Doppler frequency and the BER characteristics by controller function are verified. effect was confirmed.

• Journal of Wetlands Research
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• v.20 no.2
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• pp.124-130
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• 2018

This study was conducted to identify the characteristics of bird population dynamics using unmanned monitoring system in rice paddy. We compared the similarity of population dynamics of birds between unmanned monitoring system and field survey, and evaluated the spatial and temporal patterns of population dynamics of birds using the unmanned monitoring system. The monitoring using the system was conducted from January 1, 2014 to December 31, 2016 in Cheolwon, Dangjin, Buan, and Heanam. The images from the system were obtained at 10-min intervals from 6:00 to 20:00. The field survey was conducted once a month in Dangjin from January to December 2016. Total 91,980 images were obtained from the unmanned monitoring system. We extracted the number of individuals for herons, shorebirds, and waterfowl from the images. The population dynamics of waterbirds using the unmanned monitoring system were similar to that in field survey. Especially, population dynamics of herons was more similar than other waterbirds. It was identified that the population dynamics of herons using the unmanned monitoring system was different among the Cheolwon, Dangjin, Buan, and Heanam. Furthermore, the unmanned monitoring system was available on various time scale such as month, day, and minute. It is expected that long-term data storage using the unmanned monitoring system can be used to identify in detail and forecast the population dynamics of birds in rice paddy.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.9
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• pp.1019-1025
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• 2014

Recently, the studies of the Unmanned Aerial Vehicle(UAV) has been studied a variety from military aircraft to civilian aircraft and for general hobby activity aircraft. In particular, for small unmanned aircraft research for the ease of turning and hovering and Vertical-Off Take Landing(VTOL), have been studied mainly quadrotor unmanned aircraft is a type suitable for this study of small unmanned aircraft. The studies of these unmanned aircraft is the kinetic analysis requires complex processes, because these support by the aerodynamic forces on the unmanned aircraft study, and the controller design based on these dynamical analysis and experimental model analysis. In this paper, after the implementation of the basic attitude control based on a general PID controller, we propose concept design of the attitude control method on quadrotor attitude control by using the reinforcement learning algorithm of neural networks for non-linear elements not considered in the controller design.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.5
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• pp.525-530
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• 2016

In this paper, we proposed an image shaking index to evaluate the remote controllability of vision based unmanned vehicles. To analyze the usefulness of the proposed image-shaking index, we perform subjective tests using a virtual unmanned vehicle driving simulator. The developed driving simulator consists of a real-time multibody dynamic software of the unmanned vehicle, a motion simulator, and a driver console. We perform dynamic simulations to obtain the motion of the unmanned vehicle running on the various road surfaces such as ISO roughness level A~E roads. The motion of the vehicle body is reflected in the motion simulator. Then, to enable remote control operation, we offer to operators the image data that was measured using the camera sensor on the simulator. We verify the usefulness of the proposed image-shaking index compared with subjective index provided by operators.

• Journal of Navigation and Port Research
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• v.41 no.6
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• pp.381-388
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• 2017

Recently, renewed attention for technological applications within the maritime industry has taken place, particularly regarding unmanned vessels. There has been a lot of interest about the number of projects aiming at testing the operational feasibility of unmanned vessels, particularly in relation to technological, safety and security issues. Nevertheless, no studies have investigated this issue from the point of view of seafarers towards unmanned vessels; this paper aims at filling this gap. Data has been collected through a survey questionnaire. A Pearson correlational coefficient has been used to test the correlation between some of the variables. The results show that more than half of the respondents indicated that unmanned vessels do not contribute to an increase in accidents at sea. In addition, seafarers believe unmanned vessels will not be operational in the near future, with most of the respondents indicating a 10-20 year time frame. Thirdly, most of the respondents(both officers and ratings).

• Convergence Security Journal
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• v.18 no.5_2
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• pp.3-10
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• 2018

The drone is an unmanned aircraft that can be steered and controlled using radio waves on the ground, and the pilot moves unmanned without boarding. The history of the unmanned airplane began with military use, and the first unmanned aerial flight was the first successful flight of the 'Sperry Aerial Torpedo' drones built in the United States in 1917 with a bomb. With the development of unmanned aerial technology, the use of military drones has expanded to a wider field. Recently, the use of drones has been utilized in various fields such as agriculture, industry, logistics, broadcasting, and safety, and the scale of the market is also expanding. Although the drones are becoming indispensable to penetrate our lives, they can be used for bad purposes depending on the intended use of the user, but the risk factors are overlooked. Therefore, technical defects related to drones and accidents caused by operator's mistakes can not be completely prevented. However, privacy infringement, security leakage, and terrorism, which may be caused by illegal use of drones, It will not be inhibited and will accelerate.

• Journal of Convergence for Information Technology
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• v.8 no.4
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• pp.109-114
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• 2018

In general, the simple items we need to live in are purchased through retail stores such as supermarkets near our home. In the store, not only the items but also the management personnel and the payment instruments for the store management are located in one space called the store. Such a general store environment is gradually changing into an 'unmanned market' as a result of the development and fusion of information and communication technology (ICT). An unmanned market is an environment in which no one runs a market as the word has. An example of a typical change is Amazon's Unofficial Amazon Store. In addition, the usage and prospects of unmanned market in China are growing very meaningfully. In this study, the present situation of the unmanned market is examined in the US and China markets, and the development prospects are described. It also describes the key milestones necessary for the unmanned market.

• Journal of Aerospace System Engineering
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• v.11 no.4
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• pp.1-7
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• 2017

The development of effective design allowable values for unmanned composite aircraft is an issue of paramount concern for the industry. The application of conventional manned aircraft structural certification methods to unmanned aircraft such as prototype and technology demonstrators, can lead to excessively long development time and costs. In this paper, the determining method of composite structure design allowable values for light composite unmanned aircraft is presented to reduce to the structural weight. This paper seeks to show the applicability of composite B-basis material values as a design allowable of light composite unmanned aircraft structures. A review of different civil and UAV targets failure probability is given. From the results, the researchers can know that the requirements of light composite unmanned aircraft design allowable should be alleviated, compared to manned composite aircrafts.