• Journal of Satellite, Information and Communications
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• v.4 no.2
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• pp.12-19
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• 2009

In the modern UAV systems, the role of radar payload has been increasing with its unique performance of day-and-night operation and see-through capability over hidden obstacles. Contrary to the satellite reconnaissance, UAV is expected to provide high resolution target detection and recognition capability while frequent flight missions would deliver enhanced SAR image and local information over the target area. STK(Satellite Tool Kit) is a professional space-analysis software widely used in all phases of a space system's life cycle. The simulation of STK is efficient and accurate relatively. In this paper, the author attempt to model the UAV operation and measure the expected SAR image quality. STK(Satellite Tool Kit) is employed to analyze UAV operation and produce SAR raw data. A SAR simulator is developed to produce high resolution SAR image for various ground targets.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.7C
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• pp.971-984
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• 2004

In the coming age of information warfare, information security patterns need to be changed such as to the active approach using offensive security mechanisms rather than traditional passive approach just protecting the intrusions. In an active security environment, it is essential that, when detecting an intrusion, the immediate confrontation such as analysing the intrusion situation in realtime, protecting information from the attacks, and even tracing the intruder. This paper presents an active intrusion-confronting system using a fake session and a honeypot. Through the fake session, the attacks like Dos(Denial of Service) and port scan can be intercepted. By monitoring honeypot system, in which the intruders are migrated from the protected system and an intrusion rule manager is being activated, new intrusion rules are created and activated for confronting the next intrusions.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.83.1-83.1
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• 2017

SDO/AIA와 STEREO/EUVI 두 태양 관측 위성의 193 파장에서의 실시간 영상 이미지를 이용하여 Stonyhurst Heliographic Map을 작성하고 각각의 위성 데이터 분석으로부터 얻어진 결과들을 종합적으로 재구성하여 태양 전면 및 후면의 활동 영역들을 동시에 표출하는 태양 활동성 지도 (Solar Activity Monitoring Map)를 작성하는 프로그램을 제작하였다. 태양 활동성 지도를 이용하여 태양 후면에서의 극자외선 밝기 분포를 경도에 따라 등간격으로 나눈 후 각 지역에서 얻은 극자외선량을 실시간으로 갱신하며 그래프를 작성하는 프로그램도 함께 제작하고 그로부터 태양 후면 영역의 활동성이 향후 지구에 어떠한 방식으로 영향을 미칠 것인지 사전에 예측 가능하도록 하였다. 또한 태양 후면에서 발생하는 활동 영역 (Active Region) 및 코로나홀들을 자동적으로 탐지한 후 실시간으로 변화 정도를 추적 및 기록하는 프로그램도 제작하였다. 태양 활동성 지도는 193 파장에서 뿐만 아니라 두 위성이 공유하는 세 개의 동일 혹은 유사한 파장대 (171,211,304)에서 얻어진 데이터들도 함께 이용하여 각 파장대에서 독립적으로 작성하였는데 이로 인해 각각의 에너지 영역의 특성에 해당하는 태양 활동성을 동시에 표출하는 것이 가능하게 되었다. 이러한 프로그램을 이용하여 태양 후면에서의 활동 영역의 발생 및 변화를 사전에 인식하고 그들이 태양 전면으로 나타나기 전에 대비할 수 있는 예보 장치가 마련되었다. 본 연구들과 더불어 극자외선 영역에서의 태양 활동성 조사로부터 플레어의 발생을 예측할 수 있을 것인지의 가능성 여부를 타진하기 위해 과거 극자외선 관측에서 얻어진 활동 영역들의 데이터와 연 X-선 관측으로부터 기록된 플레어 발생 여부의 상관관계를 조사하는 연구가 현재 진행 중이다. 이러한 연구로부터 긍정적인 결과가 도출되는 경우 극자외선 영역에서의 관측 데이터를 이용하여 플레어 발생 가능성을 예측하는 새로운 방법을 제시하는 것이 가능해질 것이다.

• Journal of the Korea Society for Simulation
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• v.28 no.2
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• pp.81-88
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• 2019

Since the AESA radar scans and tracks a distant targets or ground, it requires a test field which meets far-field condition before flight test. In order to test beam foaming, targeting, and availability from cluttering and jamming, it is general to build a outdoor roof-lab test site at tens of meters high. However, the site is affected by surrounding terrain, weather, and noise wave and is also requires time, space, and a lot of costs. In order to solve this problem, theoretical near-field beam foaming method has proposed. However, it requires modification of associated hardware in order to construct near-field test configuration. In this paper, we propose near-field beam foaming method which use single LUT in order to calibrate the variation of TRM(transmit-receive module) which consists AESA radar without modification of associated hardware and software. It requires less costs than far-field test and multiple LUT based near-field test, nevertheless it can derives similar experimental results.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.20 no.4
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• pp.89-108
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• 2010

Recently many mutual authentication protocol for light-weight hash-based for RFID have been proposed. Most of them have assumed that communications between a backend server and reader are secure, and not considered threats for backend server and RFID reader impersonation. In the real world, however, attacks against database or reader are more effective rather than attacks against RFID tag, at least from attacker's perspective. In this paper, we assume that all communications are not secure to attackers except the physical attack, and considering realistic threats for designing a mutual authentication protocol based on hash function. And It supports a mutual authentication and can protect against the replay attack, impersonation attack, location tracking attack, and denial of service attack in the related work. We besides provide a secure and efficient RFID mutual authentication protocol which resists impersonation attacks on all of the entities and alow a backend server to search tag-related information efficiently. We conclude with analyzing the safety and efficiency among latest works.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.740-747
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• 2012

An Active Electronically Scanned Array(AESA) radar required necessarily as the Fire Control Radar(FCR) of recent fighters has ununiform detection range with regard to scan angle due to scan loss. Although the compensation method of scan loss in an AESA radar with variable dwell time is investigated, the effectiveness of the method in a fighter FCR with multi-function such as search, track, and missile guidance within limited resources should be considered systematically. In this paper, uniform search performance of an AESA radar using variable dwell time with regard to scan angle is derived. We assumed the search load of 50 % for case without changing dwell time in fixed frame time and showed the fighter FCR requirement for multi-function is not satisfied because the search load for the uniform search performance should be increased by about 100 %. On the other hand, in case of increasing the frame time for the uniform search performance and search load of 50 %, degradation of the search performance is shown by 86.7 % compared with the former. Based on these analyses, the effective beam operation strategy on an airborne AESA radar with uniform search performance in whole scan area is described with consideration of frame time, search load and performance as a whole.

• Geophysics and Geophysical Exploration
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• v.9 no.1
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• pp.37-43
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• 2006

In 2006, the Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) plans to undertake (subject to receiving the necessary approvals) a Pilot program for $CO_2$ storage within a depleted gas reservoir. The Otway Basin Pilot Program (OBPP) aims to demonstrate that subsurface $CO_2$ storage is both economically and environmentally sustainable in Australia. This will be the first $CO_2$ storage program in the world to utilise a depleted gas reservoir and, hence, the experience gained will be a valuable addition to the range of international $CO_2$ storage programs that are underway or being planned. A key component of the OBPP is the design of an appropriate geophysical monitoring strategy that will allow the subsurface migration of the $CO_2$ plume to be tracked and to verify that containment has been successful. This paper presents the results from modelling the predicted gravity response to $CO_2$ injection into the Otway Basin reservoir, where the goal was to determine minimum volumes of $CO_2$ that may be detectable using non-seismic geophysical techniques. Modelling results indicate that gravity measurements at 10 m spacing within the existing observation well and the planned $CO_2$ injection well would provide excellent vertical resolution, even for the smallest $CO_2$ volume modelled (10000 tonnes), but resolving the lateral extent of the plume would not be possible without additional wells at closer spacing.

• 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.