• Information and Communications Magazine
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• v.32 no.10
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• pp.18-23
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• 2015

위성 통신 기술의 비약적인 발전에 따라 군용 통신위성도 정보를 중계해주는 단순한 역할로부터 네트워크 중심전을 지향하는 군전술통신망의 중추적인 역할을 담당하게 될 것이다. 이에 따라 군 통신위성은 고속대용량 전송, 접속성, 생존성, 보안성 등 전술통신의 다양한 기능이 요구되며, 이러한 기능을 효율적으로 수행하기 위한 핵심요소가 디지털화된 OBP (On-Board Processing) 기술이다. 본고에서는 위성탑재 OBP의 환경 및 이에 따른 요구조건과 군위성에 탑재되는 OBP의 주요 기능인 채널화 및 역채널화, 항재밍 기술, 자원할당 기술 등에 대해 소개한다.

• Journal of Satellite, Information and Communications
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• v.10 no.2
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• pp.102-108
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• 2015

In general, two way satellite communication systems based on TDMA(Time Division Multiple Access) require network clock synchronization between hub station and remote terminals. This paper describes basic concepts for network clock synchronization based on NCR(Network Clock Reference) clock recovery scheme as suggested in DVB-S2/ RCS2 international standards. in addition, a new NCR insertion method has been proposed and evaluated in terms of supporting CCM mode as well as ACM mode which optimizes throughput by changing code rates and modulation types ranging from QPSK to 32-APSK.

• Journal of Satellite, Information and Communications
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• v.12 no.3
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• pp.54-62
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• 2017

China has invested for military satellite technology development to construct the space-based surveillance system from existing land-based and aerostat surveillance system since 1960s to react rapidly for deployment of marine force of United States and surrounding nations in west Pacific, south China sea and Indian ocean. China has also launched about 40 the Yaogan military intelligence satellites series for EO, SAR and ELINT fields since 2006 after the required technique with several technical experiment satellites launch and operational test. ELINT satellites transmit data from satellite to earth station in real time with construction space-based network around it. Those data are simultaneously delivered to Anti-Ship Ballistic Missile(ASBM) connected land-based C4ISR network for marine target attack. Therefore China has enhanced surveillance and attack capability to the surrounding marine nations with space-based network around it. In the future, It is considered that China will increase accurate location search, signal processing and analysis ability through a further study on its technology.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.25-31
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• 2015

In this paper, we propose PEP based on cross-layer and network coding in digital video broadcasting-return channel via satellite (DVB-RCS) networks. In particular, we propose not only a scheme of cross-layer information exchange for interaction between TCP and the resource allocation (RA) scheme in the link layer but also a tuning algorithm for the TCP contention window (CWND) by using information on the RA in the link layer and the redundancy rate for network-coded packets. The simulation results show that TCP CWND can be adjusted by RA information in the proposed protocol. Furthermore, through the transmission of network-coded packets and the proposed CWND tuning algorithm, TCP throughput is enhanced in lossy environment due to user mobility without the unnecessary resource overhead.

• The Journal of Bigdata
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• v.8 no.2
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• pp.141-148
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• 2023

Recent advancements in the integration of satellite technology and the Internet of Things (IoT) have led to the development of a sophisticated network ecosystem, capable of generating and utilizing vast amounts of big data across various sectors. However, this integrated network faces significant security challenges, primarily due to constraints like limited latency, low power requirements, and the incorporation of diverse heterogeneous devices. Addressing these security concerns, this paper explores the construction of a satellite-IoT network through the application of Software Defined Networking (SDN). While SDN offers numerous benefits, it also inherits certain inherent security vulnerabilities. To mitigate these issues, we propose a novel approach that incorporates blockchain technology within the SDN framework. This blockchain-based SDN environment enhances security through a distributed controller system, which also facilitates the authentication of IoT terminals and nodes. Our paper details the implementation plan for this system and discusses its validation through a series of tests. Looking forward, we aim to expand our research to include the convergence of artificial intelligence with satellite-IoT devices, exploring new avenues for leveraging the potential of big data in this context.

• 정보화사회
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• s.117
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• pp.23-24
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• 1997

앞으로의 사회경제활동 고도화에 따라 고속통신의 수요가 증대되어 네트워크의 고속화가 필요해지고 있는 가운데, 광역성.동보성.내재해성 등의 특성을 지닌 위성이 큰 역할을 담당할 것으로 생각되고 있다.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.41-48
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• 2013

A positioning technique using the augmentation system has been researched to improve the accuracy. The network RTK is the precise positioning technique using carrier phase correction data from reference stations and is constantly being researched. The study for the system accuracy has been performed but system integrity research has not been done as much as system accuracy. In this paper, we presented the anomaly detection algorithm by satellite system and the diagnosis algorithm to a basic research in the integrity on network RTK. And the presented algorithms are verified on the DL-V3 dual-frequency receiver and the simulated error scenario using the GSS7700.

• Bulletin of the Korean Space Science Society
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• 2003.10a
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• pp.58-58
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• 2003

과학위성 1호의 컴퓨터 시스템은 지상국 명령 및 데이터 처리, 위성 자세 제어, 위성체 운용, 상태 감시, 탑재체 운용, 배터리의 충방전 제어 등을 담당하며, 우리별 3호 위성을 통하여 검증된 컴퓨터 시스템을 기반으로 개발되었다 과학위성 1호의 컴퓨터 시스템은 탑재 컴퓨터(On-board Computer)와 비행 소프트웨어(Flight Software)로 구성된다. 과학위성 1호의 탑재 컴퓨터는 우리별 3호의 탑재 컴퓨터에 비하여 FPGA를 사용함으로써 크기 및 무게의 소형화를 추구하였고, 네트워크 제어기를 내장함으로써 통신 성능의 개선을 이루었다. 그리고 EEPROM을 장착하여 위성 운용 기간 도중에 발생할 수 있는 소프트웨어의 변경에도 대응하였다 과학위성 1호의 비행 소프트웨어는 우리별 3호의 비행 소프트웨어를 기반으로 하여 과학위성 1호의 명령 및 데이터 처리 시스템과 임무에 적합하도록 개발되었다.

• Journal of Satellite, Information and Communications
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• v.9 no.1
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• pp.45-50
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• 2014

In this paper, broadband wireless smart city network coverage was implemented targeting a city (Wonju) using the wireless mesh network. Through this, we could provide wireless network that can easily add network and be repaired easily and have high economic effect. In order to implement broadband wireless smart city network coverage, wireless mesh network has been designed through pre-survey of the region and appropriate selecting of equipment. In addition, the designed network is examined, evaluated and compared with existing network though simulation. The aim of this paper is to prove high cost saving effect of wireless mesh network and its superior performance and to suggest future oriented integrated network of Green IT though research.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2005.05a
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• pp.248-254
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• 2005

본 논문에서는 대화형 GEO 위성 네트워크에서 패킷 손실량 기대값의 총합을 최소화하는 최적 버퍼 및 타임슬롯 할당 체계를 제시한다. 이를 위해 각 단말에서의 패킷 손실량 기대값을 분석하고, 최적 버퍼 및 타임슬롯 할당 방법을 구하기 위한 최적화 모형을 정형화하고, 정형화된 모형을 빠른 시간 내에 해결할 수 있는 방법을 제시한다. 실험을 통해 제시한 방법이 기존 방법에 비해 패킷 손실량 기대값의 총합을 의미 있게 감소시킴을 보인다.