• Convergence Security Journal
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• v.14 no.6_1
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• pp.129-138
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• 2014

South Korea should correspond to the primary threat to North Korea's nuclear weapons. It is necessary to have countermeasures to solve the realistic problems of North Korea's nuclear weapons. We can intensify military pact between the United States and Korea and at the same time strengthening the current military power. Currently, we take note the threat North Korea's missile. We can not control the development of a nuclear weapon and there are possibilities that North Korea have successfully miniaturized nuclear enough to carry by the missile. We should overview and check the Korea's missile defenses system. While the direction of the overall missile defense system deployment with a focus on lower and upper air defense network. And discuss defense research should be to build a system that can be protected with a key strategic facilities and cities. While North Korea have nuclear weapon, the main issues related to North Korea's nuclear threat. The six party talks countries try to solve the problem by the international and diplomatic approach. At the same time we should make somewhat to defend measures such as military defenses of Kill chain system to protect our country. Kill Chain is on of the effective defense system. We know that North Korea do not abandon to develop nuclear weapons by diplomatic efforts. We should performed in fact by a variety of military suppression method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.7
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• pp.428-434
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• 2020

The one-shot weapon system is destroyed after only one mission. So, the system requires high reliability. Guided missiles are one-shot weapon systems that have to be analyzed by storage reliability since they spend most of their life in storage. The analysis results depend on the model and the ratio of correct censored data. This study was conducted to propose a method to more accurately predict the future failure rate of Air force guided missiles. In the proposed method, the failure rate is predicted by both MTTF (Mean Time To Failure) and MTBF (Mean Time Between Failure) models and the model with a smaller error from the real failure rate is selected. Next, with the selected model, the ratio of correct censored data is selected to minimize the error between the predicted failure rate and the real failure rate. Based on real field data, the comparative result is determined and the result shows that the proposed sampling rate can predict the future failure rate more accurately.

• Journal of Advanced Navigation Technology
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• v.20 no.5
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• pp.446-452
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• 2016

The aircraft has to be considered for safety very importantly because of peculiarity of flight in the air, so it should be retained through proper inspection and maintenance not only in production phase but also in operating phase. Recently, it is using the latest technology as engineering approach not depending on human factor to determine on maintenance needs, and domestic production rotary aircraft also has the health & usage monitoring system to measure and to monitor major components. However, continued vibration exceedance phenomenon occurred in production and operation phase because of inappropriate thresholds, and it confirmed as false alarm which is not necessary to repair. In this paper, it is described that operational concept of HUMS, and especially it contains a study result for efficiency of aircraft operation and ultimately the improvement of flight safety by optimizing HUMS thresholds to determine efficiently necessity of maintenance under limited conditions and by establishing inspection/maintenance procedures when the re-designated thresholds exceedance occurred.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.45-79
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• 2018

An increase of airplanes and military aircraft operation lead to significant demanding of residential claims by people who live in nearby airports and military bases due to noise, vibration and residential damages caused by aircraft operations. In recent years, a plaintiff has filed a lawsuit against the defendant, claiming the prohibition of using claimant's possessed land as a helicopter landing route, and the Daejeon High Court was in favour of the plaintiff. Although the Supreme Court later dismissed the Appeal Court decision, it is necessary to discuss the case of setting flight prohibited zone. In Japan, the airport noise lawsuits have been filed for a long time, mainly by environmental groups. Unlike the case that admitted residential damages caused by noise, the Yokohama District Court for the first time sentenced a judgment of the prohibition of the flight. This ruling was partially changed in the appellate court and some of the plaintiffs' claims were adopted. However, the Supreme Court of Japan finally rejected such decision from appeal and district courts. Atsugi Base is an army camp jointly used by the United States and Japan, and residents, live nearby, claim that they are suffering from mental damage such as physical abnormal, insomnia, and life disturbance because of the noise from airplane taking off and landing in the base. An administrative lawsuit was therefore preceded in the Yokohama District Court. The plaintiff requested the Japan Self-Defense Forces(hereinafter 'JSDF') and US military aircraft to be prohibited operating. The court firstly held the limitation of the flight operation from 10pm to 6am, except unavoidable circumstance. The case was appealed. The Supreme Court of Japan dismissed the original judgment on the flight claim of the JSDF aircraft, canceled the first judgment, and rejected the claims of the plaintiffs. The Supreme Court ruled that the exercise of the authority of the Minister of Defense is reasonable since the JSDF aircraft is operating public flight high zone. The court agreed that noise pollution is such an issue for the residents but there are countermeasures which can be taken by concerned parties. In Korea, the residents can sue against the United States or the Republic of Korea or the Ministry of National Defense for the prohibition of the aircraft operation. However, if they claim against US government regarding to the US military flight operation, the Korean court must issue a dismissal order as its jurisdiction exemption. According to the current case law, the Korean courts do not allow a claimant to appeal for the performance of obligation or an anonymous appeal against the Minister of National Defense for prohibiting flight of military aircraft. However, if the Administrative Appeals Act is amended and obligatory performance litigation is introduced, the claim to the Minister of National Defense can be permitted. In order to judge administrative case of the military aircraft operation, trade-off between interests of the residents and difficulties of the third parties should be measured in the court, if the Act is changed and such claims are granted. In this connection, the Minister of National Defense ought to prove and illuminate the profit from the military aircraft operation and it should be significantly greater than the benefits which neighboring residents will get from the prohibiting flight of military aircraft.

• The Korean Journal of Air & Space Law and Policy
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• v.27 no.1
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• pp.103-122
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• 2012

Nowadays, advanced countries and international community in which provide many services and profits due to rapid progress space science and technology whereas there is rising possibility of damage by collision of space object and increase of space debris. I will propose the concept and range of damage in the basis of review of space treaty and space liability convention as form of international order to fair and complete compensate to victim of accident and hazardous space activity. And, I will try to discuss possibility of compensation on personal damage and mental damage, scope of material damage, possibility of compensation about environmental contamination, issue of satellite data sending, place of damage, and so on. Also, I would like to propose establishment of space tribunal and regional cooperative agency.

• Journal of the Korea Society for Simulation
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• v.29 no.1
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• pp.39-46
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• 2020

The utilization of artificial intelligence (AI) in the engagement has been a key research topic in the defense field during the last decade. To pursue this utilization, it is imperative to acquire a realistic simulation to train an AI engagement agent with a synthetic, but realistic field. This paper is a case study of training an AI agent to operate with a hardware realism in the air-warfare dog-fighting. Particularly, this paper models the pursuit of an opponent in the dog-fighting setting with a gun-only engagement. In this context, the AI agent requires to make a decision on the pursuit style and intensity. We developed a realistic hardware simulator and trained the agent with a reinforcement learning. Our training shows a success resulting in a lead pursuit with a decreased engagement time and a high reward.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.8
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• pp.599-607
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• 2018

This paper presents a ground-to-air bistatic radar system and its implementation algorithm, which resembles an SAR(synthetic aperture radar) reconstruction algorithm. Via cooperative working between a standoff transmitting radar and an array of ground based receiving radars, it detects and images moving targets under clutter in the air. In the proposed system, the whole receiving antenna aperture is synthesized by physical ground based radars, and thus, unlike conventional SAR, it does not require long illumination time of the target area. The reconstruction algorithm uses planewave approximation based polar format processing, which alleviates the requirement of positioning the receiving radars, which can cause grating lobes if not chosen properly. We derive a reconstruction algorithm including clutter suppression and discuss implementation issues, such as the resolution of a reconstructed image and the method of compensation for the irregularity of the receiving radars' positions. A simulation that validates the proposed algorithm is also shown.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.8
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• pp.1153-1163
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• 2002

A transient analysis on temperatures of fuel and oil in hydraulic and lubrication systems in an aircraft was studied using the finite difference method. Numerical calculation was performed by an explicit method with modified Dufort-Frankel scheme. Among various missions, air superiority mission was considered as a mission model with 20% hot day ambient condition in subsonic region. The ambience of the aircraft was assumed as turbulent flow. Convective heat transfer coefficient were used in calculating heat transfer between the aircraft surface and the ambience. For an aircraft on the ground, an empirical equation represented as a function of free-stream air velocity was used. And the heat transfer coefficient for flat plate turbulent flow suggested by Eckert was employed for in-flight phases. The governing equations used in this analysis are the mass and energy conservation equations on fuel and oils. Here, analysis of fuel and oil temperature in the engine was not carried out. As a result of this analysis, the ground operation phase has shown the highest temperature and the largest rate of temperature increase among overall mission phases. Also, it is shown that fuel flow rate through fuel/oil heat exchanger plays an important role in temperature change of fuel and oil. This analysis could be an important part of studies to ensure thermal stability of the aircraft and can be applicable to thermal design of the aircraft fuel system.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.11
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• pp.979-987
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• 2012

This paper implements and integrates algorithms for terrain following of UCAVs (Unmanned Combat Aerial Vehicles): trajectory generation, guidance, and navigation. Terrain following is very important for UCAVs because they perform very dangerous missions such as Suppression of Enemy Air Defences while the terrain following can improve the survivability of UCAVs against from the air defence systems of the enemy. To deal with the GPS jamming, terrain referenced navigation based on nonlinear filter is chosen. For the trajectory generation, Voronoi diagram is adopted to generate horizontal plane path to avoid the air defense system. Cubic spline method is used to generate vertical plane path to prevent collisions with ground while flying sufficiently close to surface. Follow-the-Carrot and pure pursuit tracking methods, which are look-ahead point based guidance algorithms, are applied for the guidance. Numerical simulation is performed to verify the performance of the integrated terrain following algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.6
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• pp.781-787
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• 2010

Forecasting possible failure characteristics is very important in maintenance planning because it helps in predicting any future failures and determining the optimum replacement interval. This paper examines the time.to-failure distribution of the transfer gearbox of a J79 engine by using a probability plotting technique which is one of the most convenient techniques for reliability analysis. Various probability distributions are evaluated for determining the suitable probability distribution of the failure data of the transfer gearbox, and the resulting correlation coefficient indicates that failure data have a lognormal distribution. The expected number of unscheduled maintenance actions and the optimum replacement interval for various values of cost ratios are determined.