• Journal of Korean Society of Rural Planning
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• v.27 no.4
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• pp.55-70
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• 2021

In this study, in the field of remote sensing, where the scope of application is rapidly expanding to fields such as land monitoring, disaster prediction, facility safety inspection, and maintenance of cultural properties, monitoring of rural space and surrounding environment using UAV is utilized. It was carried out to verify the possibility, and the following main results were derived. First, the aerial image taken with an unmanned aerial vehicle had a much higher image size and spatial resolution than the aerial image provided by the National Geographic Information Service. It was suitable for analysis due to its high accuracy. Second, the more the number of photographed photos and the more complex the terrain features, the more the point cloud included in the aerial image taken with the UAV was extracted. As the amount of point cloud increases, accurate 3D mapping is possible, For accurate 3D mapping, it is judged that a point cloud acquisition method for difficult-to-photograph parts in the air is required. Third, 3D mapping technology using point cloud is effective for monitoring rural space and rural resources because it enables observation and comparison of parts that cannot be read from general aerial images. Fourth, the digital elevation model(DEM) produced with aerial image taken with an UAV can visually express the altitude and shape of the topography of the study site, so it can be used as data to predict the effects of topographical changes due to changes in rural space. Therefore, it is possible to utilize various results using the data included in the aerial image taken by the UAV. In this study, the superiority of images acquired by UAV was verified by comparison with existing images, and the effect of 3D mapping on rural space monitoring was visually analyzed. If various types of spatial data such as GIS analysis and topographic map production are collected and utilized using data that can be acquired by unmanned aerial vehicles, it is expected to be used as basic data for rural planning to maintain and preserve the rural environment.

• Journal of Aerospace System Engineering
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• v.15 no.5
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• pp.24-32
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• 2021

Personal Air Vehicle (PAV), Cargo UAS (Cargo UAS), and existing manned and unmanned aircraft are key vehicles for urban air mobility (UAM), and should demonstrate compatibility for the design of aircraft systems. The safety assessment required by for certification to ensure safety and reliability should be systematically performed throughout the entire cycle from the beginning of the aircraft development process. However, with the increasing complexity of safety critical aviation systems and the application of state-of-the-art systems, conventional experience-based and procedural-based safety evaluation methods make ir difficult to objectively assess safety requirements and system safety. Therefore, Model-Based Safety Assessment (MBSA) using modeling and simulation techniques is actively being studied at domestic and foreign countries to address these problems. In this paper, we propose a Model-Based Safety Evaluation framework utilizing modeling and simulation-based integrated flight simulators. Our case studies on the Traffic Collision Availability System (TCAS) and Wheel Brake System (WBS) confirmed that they are practical for future safety assessments.

• Journal of the Institute of Convergence Signal Processing
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• v.19 no.3
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• pp.139-146
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• 2018

Underwater acoustic communication can be applied to various area such as scientific, commercial and military survey using Autonomous Underwater Vehicles and Unmanned Underwater Vehicles. Underwater communication is studying very actively by advanced country like United States. But differ from wireless communication in the air, underwater acoustic communication has some difficult problems, ISI(Inter Symbol Interference) due to multipath and limit of transmission bandwidth due to slow propagation of sound wave. In this paper, SC-FDE and OFDM transmission system for the cancellation of ISI in conjunction with underwater acoustic channel modeling are applied to the underwater simulation of communication. The performance of these methods in the simulation guide to possibility of adopting in underwater acoustic communication algorithm. For this purpose, we compare SER performance of SC-FDE with that of OFDM for modelled underwater channel. Underwater channel is generated by Bellhop model. Simulation results show above 5dB SNR gain at 10-3 SER. And it demonstrate SC-FDE is efficient method for underwater acoustic communication.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.127-152
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• 2020

Despite growing international cooperation for maintenance of international peace and security, wars continue to occur due to conflicted state interests. Continuing conflicts has advanced development of various weapon systems such as global integrated intelligence, surveillance and reconnaissance. However, with a big increase in the number of civilian casualties caused by the weapon systems development, the international community has also advanced diplomatic efforts to minimize deaths of civilian and military personnel. Therefore, it is essential to observe the principle of discrimination between combatants and non-combatants when operating unmanned aerial vehicles (UAVs), better known as drones. Drones have become more capable of distinguishing combatants from non-combatants due to its high-tech prowess. In the operation of drones, any parties involved in combat or the war are responsible for mounting civilian casualties. In addition, it should comply with the principle of proportionality that calls for a balance between results of such action and expected military advantage anticipated from the attack. The rule of proportionality prohibits use of military force which may be expected to cause excessive civilian harm. Drones have been able to track and monitor targets for hours and select the accurate locations of the targets. The aim is to reduce civilian losses and damage to a minimum. Drones meet the standards of Article 51.4 of the Additional Protocol.

• The Korean Journal of Air & Space Law and Policy
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• v.31 no.2
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• pp.37-72
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• 2016

In the aerospace field, besides special purpose airplanes, contracts for supply of various types of products such as prototypes, unmanned aerial vehicles and space launch vehicles are increasing. In the case of the contractor, it was planned to spend a large amount of money to supply the production, but if the purchase specification that presents the quality and performance standard of the product is poor or lacks the capacity to judge the performance, consuming enormous amounts of time and money. Even if the undertaker does not have the ability to supply the products with the required performance and quality to achieve the purpose of the contract, he/she must pay the cost of burial due to the incompleteness of the work and the compensation for the cancellation of the contract. In this case, the defendant ordered the plaintiff to supply the aircraft by the Happy Box method, which is capable of ILS Offset flight as specified in the Purchase Specification, but the plaintiff attempted to supply the aircraft by the RNAV method. Although the ILS ground signal can be inspected by the RNAV method, the aircraft manufactured in the manner claimed by the plaintiff does not have the ILS Offset flight function required by the purchase specification, so the defendant can not achieve the purpose required by the purchase specification. It was a question of whether a defendant's cancellation of contract was legitimate. The aircraft, which is the object of this contract, is a subordinate substitute, so the case contract is of undertaking. Therefore, in order to complete the work in this contract, the major structural parts of the aircraft must be manufactured as agreed and have the performance generally required in the social sense. However, the aircraft delivered by the plaintiff has serious defects because the defendant can not achieve the purpose required by the purchase specification due to the lack of the ILS Offset flight function required by the purchase specification. This deficiency is impossible for the plaintiff to repair, so the defendant 's cancellation of the contract is legitimate.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.2
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• pp.256-265
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• 2021

Ground, sea and air mobility, such as vehicles, ships, and airplanes, are generally operated by people. Based on the innovative development of autonomous decision-making systems and artificial intelligence (AI) following the recent fourth industrial revolution, research and development on maritime autonomous surface ships (MASS) is been actively performed around the world. Before the realization of the commercialization of MASS in international maritime transport, it is urgent to clarify the characteristics of this ship and its international legal status. This paper aims to analyze the concern of whether a ship without crew members will eventually be operated as a fully unmanned ship or can be recognized as a ship under international law as the number of crew members is gradually reduced owing to the development stage of autonomous ships. Consequently, based on the United Nations Convention on the Law of the Sea (UNCLOS) and the regulations of the International Maritime Organization (IMO), it was found that MASS has the same international legal status as general ships. In addition this paper presents the working principles of enacting and revising the IMO Conventions and international legal measures necessary for the safe operation of MASS.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.227-260
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• 2018

Recently, as the use of drones increases, the risk of drone accidents and third-party property damage is also increasing. In Korea, due to the recent increase in drone use, accidents have been frequently reported in the media. The number of reports from citizens, and military and police calls regarding illegal or inappropriate drone use has also been increasing. Drone operators may be responsible for paying damages to third parties due to drone accidents, and are liable for paying settlements due to illegal video recording. Therefore, it is necessary to study the idea of providing drone insurance, which can mitigate the liability and risk caused by drone accidents. In the US, comprehensive housing insurance covers damages caused by recreational drones around the property. In the UK, when a drone accident occurs, the drone owner or operator bears strict liability. Also, in the UK, drone insurance joining obligation depends on the weight of the drones and their intended use. In Germany, in the event of personal or material damage, drone owner bears strict liability as long as their drone is registered as an aircraft. Germany also requires by law that all drone owners carry liability insurance. In Korea, insurance is required only for "ultra-light aircraft use businesses, airplane rental companies and leisure sports businesses," where the aircraft is "paid for according to the demand of others." Therefore, it can be difficult to file claims for third party damages caused by unmanned aerial vehicles in personal use. Foreign insurance companies are selling drone insurance that covers a variety of damages that can occur during drone accidents. Some insurance companies in Korea also have developed and sell drone insurance. However, the premiums are very high. In addition, drone insurance that addresses specific problems related to drone accidents is also lacking. In order for drone insurance to be viable, it is first necessary to reduce the insurance premiums or rates. In order to trim the excess cost of drone insurance premiums, drone flight data should be accessible to the insurance company, possibly provided by the drone pilot project. Finally, in order to facilitate claims by third parties, it is necessary to study how to establish specific policy language that addresses drone weight, location, and flight frequency.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.1
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• pp.28-33
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• 2016

Batteries are used for main power engine in the fields such as mobiles, electric vehicles and unmanned submarines, for starter and lamp driver in general automotive, for emergency electric source in ship. These days, lead-acid and the lithium ion batteries are increasingly used in the fields of the secondary battery, and the lead-acid battery has a low price and safety comparatively, The lithium ion battery has a high energy density, excellent output characteristics and long life, whereas it has the risk of explosion by reacting with moisture in the air. But Recently, due to the development of waterproof, fireproof, dustproof technology, lithium batteries are widely used, particularly, because their usages are getting wider enough to be used as a power source for hybrid ship and electric propulsion ship, it is necessary to manage more strictly. Hybrid ship has power supply units connected to the packets to produce more than 500kWh large power source, and therefore, A number of the communication modules and wires need to implement the wire inspection and monitor system(WIIMS) that allows monitoring server to transmit detecting voltage, current and temperature data, which is required for the management of the batteries. This paper implements a low price type wireless inspection and monitoring system(WILIMS) of the lithium ion battery for hybrid vessels using BLE wireless communication modules and power line modem( PLM), which have the advantages of low price, no electric lines compared to serial communication inspection systems(SCIS). There are state of charge(SOC), state of health(SOH) in inspection parts of batteries, and proposed system will be able to prevent safety accidents because it allows us to predict life time and make a preventive maintenance by checking them at regular intervals.