• Journal of Space Technology and Applications
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• v.2 no.1
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• pp.30-40
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• 2022

This paper illustrates the trajectory design of drift distance recovery after initial launch and proximity operation when verifying rendezvous/docking technology using nanosatellites. The rendezvous/docking is a technology that is the basis of on-orbit servicing technology and is a preemptive process essential for approaching a target object. In particular, since it is difficult to verify in space, nanosatellites have recently been used to reduce the risk and cost of the development stage. Therefore, this paper not only introduces the configuration and specifications of thrusters for nanosatellites but also designs relative trajectories that can take into account the thrust limitations which come from the small size and low power of nanosatellites. In addition, we intend to be helpful in later designing scenarios according to the improvement of available thruster performance through comparison of trajectories and thrust usage with cases without thrust limitations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.4
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• pp.59-65
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• 2022

In this paper, a digital active phased array antenna is briefly introduced and beam forming method for a dual-channel side-lobe blanking applied to blank the side-lobe of the main beam is described. Next, the antenna performance was verified from results of design and antenna near-field measurement for the antenna main beam and side-lobe blanking beam. Then, a single-channel side-lobe blanking beam forming method was proposed to reduce the number of channels than the existing system operating dual-channel side-lobe blanking beam and weight distribution for each element of the side-lobe blanking antenna was designed with the proposed method. Finally, the designed single-channel side-lobe blanking beam pattern and blanking ability were verified and compared with the dual-channel side-lobe blanking beam. In addition, by comparing/verifying the conventional dual-channel and the proposed single-channel side-lobe blanking beam patterns measured through the receiving near-field test of the digital active phased array antenna and their ability to blank side-lobe of the main beam, validity of the proposed method for forming single-channel side-lobe blanking beam was confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2579-2586
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• 2014

It is crucial to set up early the required performance of surface ship for preventing the risk factors such as an excess of performance, cost and period in development stage. In this study, MOP and MOE are proposed to establish the method for deriving alternatives, MOP represents the defensive effect for anti ship missiles and MOE is the ratio of cost and performance. The 16 engagement scenarios which selectively install RF decoy, RF jammer, CIWS and anti air missile are suggested. The simulation results by using NORAM tool operated by ROK Navy show that the ship survivability is 0.605~0.975 and MOP is 0.301~0.887. The analyzed results represent the operating scenario with RF decoy, RF jammer and short range anti air missile is the best cost and effectiveness measure.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.64.3-65
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• 2021

인공지능 기계학습에 의한 한문고전 자동번역기는 승정원일기 뿐만 아니라, 한국 고문헌 중 천문 기록에 특화되어 한자로 된 천문 고전을 한글로 번역해 서비스하고 있다. 한국천문연구원은 한국지능정보사회진흥원이 주관하는 2019년도 Information and Communication Technology 기반 공공서비스 촉진사업에 한국고전번역원과 공동 참여하여 이 자동 번역기 개발을 완료한 것이다. 이 번역기의 개발 목적은 초벌 번역 수준일지라도 문장 형태의 한문을 한글로 자동 번역하는 것이며, 이 연구는 현재 번역기 운용 현황을 서비스 별로 분석하고자 한다. 자동 번역관련 서비스는 크게 3가지이다. 첫째, 누구나 웹 접속을 통해 사용 가능한 한문고전 자동번역 대국민 서비스이다. 1년간 자체 시험을 거쳐 2021년 1월 12일 시험판을 오픈하여 운용 중에 있다. 둘째, 기관별로 구축된 코퍼스와 도메인 특화된 번역 모델 등을 관리할 수 있는 한문고전 자동번역 확산 플랫폼 서비스이다. 대국민 서비스와 함께 클라우드 기반으로 서비스되며, 한국고전번역원이 관리를 담당한다. 셋째, 자동번역 Applied Programmable Interface를 활용한 한국천문연구원 내 자체 활용이 가능한 천문고전 자동번역 서비스이다. 서비스 현황 분석은 기관별 관리 서비스에 해당되는 한문고전 자동번역 확산 플랫폼에서 집계하여 제공하는 대시보드의 통계 기능을 활용한다. 각 서비스별 문장과 파일 번역 이용 건수, 번역 속도, 평균 자수 뿐만 아니라, 번역 모델 프로필에 따른 이용률 분석이 가능하다. 이에 따른 주요 분석 중 하나인 올해 전체 번역 이용 건수는 한 해 각 기관의 평균 방문자수 대비 87% 성과 목표에 해당되는 약 38만 건에 근접할 것으로 예측된다. 이 자동 번역기는 원문 해독 시간을 단축시키는 효과와 함께 미번역 천문 고문헌의 활용성을 높여 다양한 연구에 기여할 것이다.

• Journal of Advanced Navigation Technology
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• v.28 no.1
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• pp.77-86
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• 2024

'UAS flight recording system' is a system that is mounted on an unmanned aircraft system consisting of various components and records flight-related data. The data recorded by this system should be used for aviation accident and incident investigations to prevent similar accidents. In particular, for the category of UAS with high operating risk, safety devices close to that of manned aircraft are required, and it is urgent to develop flight recording systems reflecting the characteristics of the UAS to secure airworthiness. This paper highlights the need for UAS flight recording systems for aviation accident and incident investigations and seek a method to derive flight recording system parameters for 'Certified Category' with high operational risk. To this end, Inter-City UAM was used as a concrete use case, and the process of approaching system parameters was devised by assuming accident occurrences and hazards from mission profiles and scenarios. As a result of the study, it was confirmed that parameters could be derived through this process.

• Aerospace Engineering and Technology
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• v.13 no.1
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• pp.142-152
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• 2014

This paper analyzes the conjunction events of Korea satellites by year or kind of satellite using CSM, which is provided by JSpOC. If multiple CSM for single conjunction event are available, consistency analysis is performed using minimum range of CSM. And this paper presents the contact analysis results with space objects if there is a radar system in Korea. The effectiveness of Korea's radar system is analyzed by calculating the access time or frequency with space objects. Furthermore, we investigate the radar systems of other space agencies and find the specific parameter depending on the operating environment. Using this information, we define the requirements of radar system, which is appropriate the Korea.

• The Journal of the Korea Contents Association
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• v.10 no.4
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• pp.115-122
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• 2010

Most of intelligent services provided today work based on the users' location. Numerous devices for indoor localization services have their own characteristic functions and operating systems, we need the interoperability and diversity of middleware to connect and control these devices. The indoor localization method using existing inertial sensors are relatively less efficient because of additional cost according to the size of space. Accordingly, the indoor user localization method proposed in this study supports integrated services using OSGi framework, an open source project, and solves problems in inertial sensor based on accurate distance to a specific object measured using ultrasonic sensor. Furthermore, it reduces errors resulting from difference in response rate by adding the reliability item.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.59-66
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• 2000

This study describes the precise DTM by image processing method through scanning the positive film of aerial photo using scanner instead of plotter. First, scanned the positive film of aerial photo by drum scanner and flatbed scanner in different resolution, and then compared the height from image processing method using auto correlation method with height which is taken using $50^m{\times}50^m$ grid in 1 :5,000 geographical map. It shows that heights from aerial photo image of high resolution obtained from scanner are comparable to the heights from 1：5,000 geographical map.

• 한국공간정보시스템학회:학술대회논문집
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• 2000.06a
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• pp.51-63
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• 2000

현재 지리정보 기술의 세계적인 추세는, ISO 나 OGC 등의 국제 표준기구에서 제시하고 있는 상호 운용성을 지원하기 위한 3계층 구조의 인터넷 GIS로 나아가고 있다. 특히 OGC 에서는 인터넷 환경에서 표준 인터페이스를 통해 다양한 데이타 소스의 지리정보를 접근하여 기존의 웹 브라우저로 표현하는 구조의 웹 매핑 테스트베드를 제시하고 있다. 3계층 구조의 인터넷 GIS에서의 문제점은 각 계층간의 통신 횟수와 데이타 전송량이 많고, 미들웨어 컴포넌트에서의 데이터 변환으로 인해 속도가 저하되는 것이다. 데이타 전송량과 데이타 변환량으로 인한 문제점은 미들웨어 계층에서 공간 데이터를 캐슁함으로써 해결될 수 있다. 본 논문의 핵심 아이디어는 미들웨어 컴포넌트들 사이에 공유 캐쉬를 두고, 여러 클라이언트들이 공통적으로 접근하는 데이타를 중심으로 캐쉬를 관리하는 것이다. 본 논문에서 제시하는 기법은 질의 영역에 대해 확장된 영역을 캐슁함으로써, 하나의 클라이언트 입장에서 근접한 영역의 질의에 대한 사용자 응답 시간을 줄일 수 있다. 또한 캐쉬 교체를 위해 접근 빈도수 중심의 교체 함수를 취함으로써 여러 클라이언트들에 대해 데이타의 재사용성을 높일 수 있다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.16 no.2
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• pp.235-242
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• 1998

This study aims to detect and to reduce the multipath errors which are main errors source in high precious surveying such as GPS-aided aerial triangulation and Car Navigation. which reference receivers being fixed, when kinematic receivers move continuously, multipath is performed using smoothed code measurement and pure code measurement in the network. Through this methods, 3D RMS errors are reduced into about 30% in the single differential code solution to the kinematic receiver. This is based on the fact that the network adjustment are performed at multiple reference receivers, but positioning is carried out by the single differential methods between a reference receiver and a kinematic receiver. So it was supposed that this methods reduced the correlation errors including the atmospheric errors using the nearest receivers and can be mixed with another methods.