• Broadcasting and Media Magazine
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• v.24 no.3
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• pp.76-81
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• 2019

지상파 UHD 방송의 주요 특징 중 하나는 IP기반의 양방향 서비스이다. 데이터 전송 측면에서 보면 고화질 영상을 많은 사람들이 동시에 수신할 수 있는 브로드캐스트 서비스이면서도 통신망과의 연결을 통해 콘텐츠를 확장할 수 있는 확장형 서비스라고 할 수 있다. 초고속, 초저지연, 초연결 등 세가지 중요한 특징의 5G 서비스는 이러한 지상파 UHD 방송과 어떻게 접목될 수 있을까? 초고화질로 연결되는 현장 상황은 실시간 방송의 품질을 높일 것이며, 초저지연은 무선라이브 제작환경의 혁신을 가져올 것이다. 또한 초연결성은 고품질 미디어 서비스 단말기의 무한 확장을 가져올 것이다. 이처럼 통신 기술의 혁신적인 발전은 연결형 서비스로 거듭난 지상파 방송 서비스의 진화에도 많은 영향을 미칠 것이다. 본 고에서는 5G에서 달라진 기술 혁신의 내용과 미디어 소비 환경의 변화가 지상파 방송 미디어 서비스를 어떻게 변화시키는지 논의해 보고자 한다.

• 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.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.4
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• pp.441-450
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• 2016

Wireless multi-hop communication is one of the key technologies to operate Unmanned Ground System (UGS) networks efficiently. Conventionally a lot of routing protocol has been developed and studied for multi-hop networks like Mobile Ad-hoc Network (MANET). However, the routing protocol for the unique environment of the UGS requires further studies, since conventional routing protocols cannot be used itself for UGS networks. In this paper, we propose the Betweenness Centrality based Geographic Routing (BCGR) which considers the main function of UGS. BCGR utilizes expanded ego betweenness centrality, mobility and location information error, respectively. We have conducted a simulation study for evaluating the performance of the BCGR using ns-3, and our simulation results show that BCGR outperforms the conventional routing protocols such as AODV and GPSR in terms of end-to-end transmission reliability, throughput and delay.

• Journal of the Korean Society for Railway
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• v.15 no.1
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• pp.29-36
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• 2012

This paper includes ATP(Automatic Train Protection) simulator development and ATP algorithm verification to allocate wayside and train-borne and verify ATP functions of communications based train control system. The train control system has some characteristics such as simple structure and high safety when wireless communication technology is applied to the train control system. Especially, vital functions can be performed with in wayside and train-borne ATP. However, different system can be realized because I/F contents vary in accordance with vital functional allocation of ATP. Drawing characteristics in accordance with wayside and train-borne functional allocation and drawing I/F details affected by such characteristics are needed accordingly. This paper includes ATP simulator development creating train location information by direct activation of an electric motor, verifies train safety distance control algorithm of ATP by functional allocation such as train movement authority and train speed limit to ATP, and draws any supplementation needed. Appropriate simulated environment for verify ATP algorithm and main factors that affect to the ATP function were confirmed.

• Journal of Internet Computing and Services
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• v.7 no.4
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• pp.45-55
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• 2006

This paper proposes a virtual target overlay technique for a realistic training simulation which projects a virtual target on ground-based CCD images according to an appointed scenario. This method creates a realistic 3D model for instructors by using high resolution GeoTIFF (Geographic Tag Image File Format) satellite images and DTED(Digital Terrain Elevation Data), and it extracts road areas from the given CCD images for both instructors and trainees, Since there is much difference in observation position, resolution, and scale between satellite Images and ground-based sensor images, feature-based matching faces difficulty, Hence, we propose a moving synchronization technique that projects the targets on sensor images according to the moving paths marked on 3D satellite images. Experimental results show the effectiveness of the proposed algorithm with satellite and sensor images of Daejoen.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.9
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• pp.752-759
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• 2012

This paper presents a mission orbit design method for spacecraft which use the sun-synchronous and ground repeat orbits. In this work, we have proposed a new design procedure, "Nonlinear simulation-based numerical optimization technique" using the commercial S/W's such as STK (Satellite Tool kit) and Matlab, which are widely adopted S/W's in the area of orbital mechanics and engineering analysis. Inclusion of all the perturbation effects on the spacecraft not only can more precisely satisfy the mission requirements for sun-synchronicity and repeated ground track, and also operational requirements such as minimum change in the S/C local time, maximization of the contact time with a specified ground station, etc. can be appropriately considered. Design examples for LEO sun-synchronous mission are presented to demonstrate the usefulness of the proposed method in this paper.

• Journal of Broadcast Engineering
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• v.15 no.2
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• pp.192-204
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• 2010

As illegal distribution of the terrestial DTV broadcast program occurs very frequently in on-line, the needs to protect broadcast program have increased. In this paper, a new approach to implement a system for terrestial DTV broadcast program protection based on program protection information(PPI) is proposed. In our approach, the broadcast program is recorded with encryption according to redistribution condition of the PPI and packaged into a file with key information and PPI together. And we also define a set of domain protocol for supporting user fair-use of broadcast program. In the proposed system, copy control can also be provided by process of home domain management. Implementation results show that our system can protect broadcast programs with efficiency and can support conditional distribution within home domain in order to satisfy user fair-use.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.05a
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• pp.250-253
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• 2014

Due to limited resource, marine communication is severely limited when compared to communications in land. Radio relay facilities, etc. based on a wired network through a long distance communication is possible. In addition, the aircraft is in the air, the ground-based network service based on long-range straight-line distance and elevation (LOS: Line of Sight) communications. On the other hand, the distance in a straight line to the sea, the sea level because communication is limited or through satellite, underwater communications relay equipment installed in the communication scheme has been investigated.. In this paper, using TCP-based real-time joint maritime security communication links were studied. Harsh marine environment, real-time communication that can provide secure communications and propose a LINK joint. In this study, more secure, and convenient communications at sea, a plan was presented to you.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.143-146
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• 2009

브로드밴드 네트워크의 발전으로 네트워크를 통해 콘텐츠를 제공하는 TV포털이나 IPTV 서비스가 활성화되고 있으며 시청자들은 온디멘드 서비스에 익숙해지고 있다. 하지만 지상파 방송사는 방통 융합 서비스의 핵심이라고 할 수 있는 양방향 네트워크를 갖고 있지 않으므로 증가하고 있는 시청자의 온디멘드 서비스 요구에 적절히 대응하지 못하고 있는 실정이다. 따라서 지상파 방송사의 입장에서는 상대적으로 운용비용이 많이 드는 인터넷과 같은 양방향 네트워크의 전송 효율을 높이기 위해 온에어 DTV 채널을 기반으로 인터넷을 접목하여 TV와 PC 나아가서는 모바일 단말과 같은 다양한 단말에서 콘텐츠와 관련 데이터를 공유할 수 있는 DTV 기반의 크로스미디어 서비스가 적합하다. 이에 본 논문에서는 이러한 크로스미디어 서비스를 제공하기 위해 필요한 콘텐츠 제작 요소기술과 온에어와 인터넷을 통해 콘텐츠와 관련 정보를 송수신하는 요소기술을 제안하는 바이다.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.119-126
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• 2008

도시공간정보 통합플랫폼은 도시의 체계적이고 과학적인 관리, 특히 지상 및 지하시설물 관리에 필요한 센서 및 미들웨어 기술, 유무선 네트워크, GIS-USN 연계 등의 요소기술이 집적된 지능형 도시운영 기반환경으로 정의된다. 도시공간정보 통합플랫폼은 상수도, 하수도, 가스, 난방, 송유, 전력, 통신의 7대 지하시설물과 교량, 육교, 터널 등 도시 지상시설물 등 도로기반시설물 관리를 지능화 할 수 있는 기반 환경을 제공하는 역할을 수행해야 한다. 본 연구에서는 지능형 도시공간정보 통합플랫폼 개발을 위해 플랫폼의 비전을 설정하고 개방형 분산처리 레퍼런스 모델(RM-ODP, Reference Model for Open Distributed Processing)의 적용을 통해 개발전략을 도출하였다.