• Journal of the military operations research society of Korea
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• v.34 no.3
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• pp.31-40
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• 2008

The aircraft manufacturing industry is a profitable business and has the potential to be an important export business. Our trade deficit needs to be improved in aircraft manufacturing part. Our national aircraft industry, which has been recognized for its quality in many domestic and international Air Shows, has developed the T/A-50 aircraft from the origins of the KT-1. With the ongoing development of the next generation fighter planes and helicopters, business for the next generation domestic air cargo has bright prospects. Judging by the history of the overseas air force dispatch during the Vietnam, Gulf, and Iraqi wars whose main mission was air transportation, there will be many opportunities to show the excellence of Korean air cargo in the future. The purpose of this study is to discover the optimal scale of air cargo development using the AHP method. The authors evaluated the scale of air cargo in size and capacity based on the following 5 standards used Korean developing airliner: usability, economics, technology, safety, and environmental friendliness. Then, the authors modified specific standards suitable for air cargo based on literature review Decision-making groups were chosen for suitability of expert staff in charge because they could represent for leading opinions in this specialized area especially as in practical aspects. The participants of the evaluation were pilots, transportation officers and management staff in the KAI who have experienced over 5years.

• Journal of the Korean Society for information Management
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• v.29 no.3
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• pp.187-214
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• 2012

Libraries are founded to ensure the intellectual freedom of citizens, and citizens have the right to confidentiality regarding their needs, information access, and information use. Protecting users' privacy is critical to safeguarding their freedom of speech, freedom of thought, and freedom of assembly. Libraries and librarians should seriously concern themselves with their users' privacy because protecting this privacy is part of their most important mission, and, in doing so, users can truly enjoy their intellectual freedom. This study extensively investigated and analyzed the possibility of privacy invasion that may occur in libraries. As a result, cases of potential invasion of privacy in libraries were summarized in the following three categories: violations occurring in the process of national or law agencies' enforcement operations; violations occurring in the process of routine library services such as circulation, reference, online searching etc.; and violations occurring by outsourcing library services.

• Journal of Digital Convergence
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• v.14 no.10
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• pp.173-181
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• 2016

The objective of this study is to subdivide the tactical considerations (METT+TC; Mission, Enemy, Terrain & Weather, Troops available, Time available, Civil considerations) through Delphi method and prioritize those via AHP (Analytic Hierarchy Process). Though it has been taken for granted that the tactical considerations were inevitable for decision making relating to military operations, their segmentation and priority have not been studied sufficiently in military. The data for Delphi method and AHP were based on interview with military experts and questionnaires answered by those. Six tactical considerations were segmented into 34 sub-considerations by Delphi, and Six tactical considerations and 34 sub-ones were prioritized through AHP in attack and defense aspects. If the research results will be embedded into database of automatic command and control system (e.g. ACTIS; Army Tactical Command Information System), effective decision-making process will get easier and faster.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.12
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• pp.1281-1286
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• 2015

Fatigue cracks can be generated in aircraft as a result of the cumulative time spent during flight operations, which can extend for long periods of time and cover a variety of missions. If a crack occurs in an aircraft's main spar, it can generate many problems, including a lift time reduction. To solve this problem, it was necessary to perform an analysis of fatigue crack growth in the fatigue critical locations. Much time and expense is involved in generating the stress needed for a crack propagation analysis over a long period of time to obtain the amount of data required for an actual aircraft. In this paper, an algorithm is developed that can calculate the spectrum of stress over a long period of time for a mission by the Southwest Research Institute, which is based on the short-time load factor data produced using the peak-valley cycle counting method.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.12
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• pp.14-21
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• 2013

In satellite operations and space exploration missions, a ranging is one of the most essential technologies to get its navigational information of space probes. Recently, the importance of cross-support between space agencies is increasing for more fine performance of space mission. For cross-support, mutually compatible ranging system between space agencies is recommended. For these reasons, the consultative committee for space data systems (CCSDS) recommends pseudo noise (PN) ranging as a digital standard ranging system. The length of PN sequence in CCSDS standard is proper for deep space missions, however, it is too long to use for ranging in near earth missions. In this paper, we propose Variable Length PN sequence schemes suitable for ranging of near earth satellites, such as low-earth orbit (LEO), medium-earth orbit (MEO) and Geostationary orbit (GEO). Therefore we propose variable length PN sequence ranging system including CCSDS standard for multiple missions.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.4
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• pp.377-386
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• 2015

DubaiSat-2 is the first satellite developed in Korea equipped with a hall-effect thruster. In this paper, the performance of the DubaiSat-2 hall-effect thruster is verified by analyzing the orbit information of DubaiSat-2. The preparation and performance of orbit operations during 8 months after launch (2013.11.21., UTC) is emphasized and the effects of solar activity on orbit evolution is analyzed. In particular, the hall-effect thruster's thrust is estimated by analyzing difference between observed orbit evolution and predicted orbit. As a result, the estimated thrust is similar to the ground experiment result of 11 mN. The summarized result in this paper would be important reference to improve the stability and effectiveness of satellite operation during the early operation and normal mission lifetime in case of low Earth orbit satellites.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.7
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• pp.738-746
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• 2016

As the trend of future war has been changed to network centric warfare, tactical data link should be needed for fast and accurate situation awareness. Nowadays, Korean air force conducts military operations by using aircrafts equipped with Link-16. The Link-16 can conduct multiple mission at the same time because it supports multi-net capability. Due to lack of frequency resource, the way to share the frequency with other systems has been studied and using L band with radar is considered as one of the candidates bands. However, the data link can be affected by the interference from radars when it shares the L-band because the L-band in Korea is already assigned to long-range detection radars. In this paper, we evaluate operational possibilities of tactical data link in the L-band based on Link-16.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.33-38
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• 2012

A LEO Satellite performs automatic initial operations by FSW after separation from a launch vehicle. After initial operation by FSW is finished, preparation for normal operation is performed by ground during bus initial activation and checkout phase. First of all, we check state of health of the satellite including solar array deployment status. After then, each unit of spacecraft bus is activated and checked. After activation and checkout of every units used for normal operation, we check maneuver performance for imaging mission and orbit maintenance performance. Because the Bus IAC is performed during limited ground contact time, every detailed procedure must be designed considering ground contact. Therefore, the Bus IAC procedure is separated into several parts based on ground contact duration. In addition, the procedures for every possible operation including expected situation as results of IAC procedures and unexpected contingency situation must be prepared. The contingency operation is also designed based on ground contact duration. The LEO satellite was successfully launched and the Bus IAC was successfully performed. In this paper, we explain design concepts and execution results of Bus IAC.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.6
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• pp.35-40
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• 2019

In this research, we suggest a real-time tele-driving system for unmanned drone operations using the LTE communication system. The drone operator is located 180km away and controls the altitude and position of the drone with a 50ms time delay. The motion data and video from the drone is streamed to the operator. The video is played on the operator's head-mounted display (HMD) and the motion data emulates the drone on the simulator for the operator. In general, a drone is operated using RF signal and the maximum distance for direct control is limited to 2km. For long range drone control over 2km, an auto flying mode is enabled using a mission plan along with GPS data. In an emergency situation, the autopilot is stopped and the "return home" function is executed. In this research, the immersion tele-driving system is suggested for drone operation with a 50ms time delay using LTE communication. A successful test run of the suggested tele-driving system has already been performed between an operator in Daejeon and a drone in Inje (Gangwon-Do) which is approximately 180km apart.

• Current Industrial and Technological Trends in Aerospace
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• v.5 no.2
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• pp.33-42
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• 2007

위성체 총조립 및 시험(AIT ; Assembly, Integration & Test)을 위한 전기지상지원장비(EGSE ; Electrical Ground Support Equipment)와 위성 임무 준비 및 운용을 위한 관제시스템(MCS ; Mission Control System)의 공동 개발은 미국과 유럽의 위성사업 기관 및 업체에서 지금까지 많은 연구가 되어 왔다. 비록 두 시스템이 다른 목적으로 사용되고 있지만 기술적으로 유사한 기능을 갖는 시스템으로서 많은 공통점과 호환 가능성을 갖고 있다. 두 시스템의 공동 개발은 시스템 개발과 위성 운용 교육 및 준비에 필요한 비용 절감뿐만 아니라 AIT 단계에서 위성운용단계로의 자연스러운 전환이 가능하다. 이는 AIT 단계에서 공통지상시스템 하드웨어 및 운영시스템, 시험/운용 절차서, 위성 데이터베이스의 사전 검증이 이루어지기 때문이다. 또한 위성 운용 요원의 AIT 참여를 통해 공통지상시스템 운용 훈련과 위성 관제 지식 습득이 자연스럽게 이루어 질 수 있다. 이로서 사업 일정과 개발 위험도를 최소화 할 수 있다. 이러한 두 시스템의 공통성과 호환성 및 공통시스템 개발 장점이 있기에 EGSE와 MCS의 공통 기능에 대한 표준화 작업은 1986년 만들어진 COES(Committee for Operations and EGSE Standard)에서 공식적으로 논의되기 시작하여 1994년 CNES와 ESA의 발의로 제정된 ECSS(European Cooperation for Space Standards)를 통해 국제 표준(ISO, CCSDS 등)을 바탕으로 한 지상시스템에 대한 유럽 표준화 작업이 ECSS-E-70 Working Group에서 진행되고 있다. 또한 검증된 지상시스템의 핵심 운영시스템의 소프트웨어 모듈의 재사용을 통해 최근에서 다양한 공통지상시스템이 개발되어 운용되고 있다. 이러한 배경으로 국내에서도 저궤도 위성 개발에서 EGSE 핵심 모듈인 TM/TC 처리 및 Database 관리 모듈을 AIT 단계에서 개발 및 검증 후에 MCS에서의 재사용을 적극적으로 고려하고 있다. 앞으로 국제적인 추세에 따라 AIT 및 지상국간의 기술 및 인력 교류와 핵심모듈 개발을 통한 공통지상시스템 개발의 활발한 전개가 예상된다.