• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1824-1833
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• 2016

In this paper, we propose networked airborne relay-based positioning scheme (N-ARPS) based on time division multiple access (TDMA) networks to improve the performance of relative navigation (RelNav). To integrate the ARPS into TDMA, there are three problems such as slot allocation, selection of airborne relays, and method for signal loss to be solved. A subframe of N-ARPS is designed to assign the slots for broadcast and relay of navigation signals consecutively to minimize the effect of mobility. The selection algorithm determines the optimum set of airborne relays by selecting evenly distributed nodes depending on their distances to the master station. Finally, we uses precise position location information (PPLI) messages, which are received in data transmission period, to estimate a user position when the navigation signals are missing. The simulation results indicate that N-ARPS significantly improves user accuracy over RelNav.

• Korean journal of communication and information
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• v.59
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• pp.211-232
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• 2012

The N Screen service has been focused because of the explosive growth of Smart media. However, between content producers and service providers have been causing the copyright issue while N-Screen service providing real-time channels. In this study, the current copyright issues are analyzed by examining at the right relationships associated with the right of communication to the public and private copy that caused by sling box which is activated N Screen.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1104-1111
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• 2012

Airborne tactical networks is used to air-to-air or air-to-ground operation and have a large propagation delay. All nodes share the data by using TDMA-based broadcasting. In airborne tactical networks, each time slot needs the guard time to ensure the broadcasting because the collisions occur due to the large propagation delay. However, the channel utilization of the networks can be greatly degraded due to the waste of guard time. In this paper, we propose Inter-Transmitter Distance-Based TDMA (ID-TDMA) scheme which ensures the broadcasting while improving the channel utilization by reducing the guard time with the inter-transmitter distance information. The proposed scheme shows the effectiveness through the performance evaluation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.3
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• pp.187-196
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• 1990

This paper presents the design and implementation of a File Transfer Protocol between PC's which are connected through public network. The file handling system was implemented under 3B20S/UNIX which has connections to IBM-PC under MS-DOS. In designing the Protocol we use Kerimit Protocol which supports a file transfer between several kinds of PC's, and we extended the Kermit Protocol to have window function and file managing system. Users prepare data at PC and are able to send it to host computer and can receive, inquire, and delete file in host computer.

• Journal of Information Management
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• v.42 no.2
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• pp.1-21
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• 2011

The copyright law is the greatest legal tool for promoting access to knowledge and information by striking a balance between owners rights and users rights. For libraries, copyright limitations and exceptions are critical to meeting our missions to support learning and research, promote the flow of information, provide equitable access to information to the public, preserve intellectual and cultural heritage. Based on these reasons, this study analysed the limitation of copyright law of Korea for library, suggested improvement of reproduction for the library preservation and distribution including rental and lending, printout and transmission of internet information resources, copy of library materials which are rarely available through normal trade channel and government publications, reproduction and electronic transmission for persons with disabilities, and proposed fair use model(limitations on exclusive rights) for libraries.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.1
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• pp.153-156
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• 2005

현재 육상과 해상간의 통신은 Inmarsat 단말기를 이용하여 전화, 텔렉스, 팩스, 전자메일(E-mail) 및 데이터 통신을 한다. 기존 전자메일 프로그램은 비싼 통신요금과 저속의 위성통신 환경에서 최대한 통신비용을 줄이기 위한 목적으로 개발되었다. 그리고 팩스를 이용하는 경우는 관련문서를 출력 후, 송신하기 때문에 시간과 비용이 낭비된다. 이에 현재 많은 나라에서 Inmarsat을 이용한 육상과 선박간의 서로 다른 네트워크 상의 정보를 공유할 수 있는 방법을 모색하고 있다. 따라서 본 논문에서는 기존의 육상과 해상간의 전자메일 시스템과 팩스 기능을 통합한 육상과 해상을 모두 지원하는 인터넷 기반의 팩스 서비스 시스템에 관한 연구이다. 이를 위하여 기존 전자메일 시스템과 공중전화망(PSTN : Public Switched Telephone Network)을 연결하는 하드웨어적인 모듈을 설계하였다.

• Journal of Korean Society for Geospatial Information Science
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• v.12 no.2 s.29
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• pp.3-9
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• 2004

The Broadcasting system is very important part of human lift that preceding to people news, nation plan, sport, drama, leisure and politics. The product of maded by brocasting system conveyed the whole country by radio signal. A brocasting station operate the brocast product radio trial network in the mountain. Recently a height of new building, concrete structure is very large and higher then old one. Since one does or says, noise occur to radio and TV signal whole nation. In this study, Taejun Sikjang mountain and Cheunan-Heuksung mountain where occurred radio noise chosen as a sample, and analysis 3D simulation and plane check. Accordingly come to conclusion condition of noise occurred radio antenna.

• Electronics and Telecommunications Trends
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• v.15 no.3 s.63
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• pp.28-41
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• 2000

인터넷 멀티캐스트 서비스는 지난 10여 년 동안의 기술 발전에도 불구하고 아직 보편화되지 않았다. 본 고에서는 최근 IETF에서의 인터넷 멀티캐스트 보급을 촉진시키기 위한 새로운 기술들에 대하여 살펴보고자 한다. 먼저, 관리범위 멀티캐스팅에서는 공중 인터넷망으로 진입하는 멀티캐스트 트래픽의 흐름을 도메인 내에서 한정시키고자 하고, MSDP에서는 인터도메인 트리 구성을 위한 송신자 위치파악 메커니즘을 정의한다. 한편, 최근 호주에서 개최된 제47차 IETF 회의에서 가장 큰 주목을 받았던 SSM에서는 멀티캐스트 그룹주소뿐만 아니라 송신자의 주소를 토대로 멀티캐스트 라우팅을 수행하여 인터넷 멀티캐스팅에 대한 관리 및 구현의 용이성을 향상시키고자 하며, 특히 인터넷망 사업자들의 큰 관심을 얻고 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.72-74
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• 2021

현재의 저궤도 위성 통신망은 일반적으로 지상기반 네트워크와 공중 기반 네트워크로 구성되지만 최근에는 위성들간의 애드 혹 네트워크 기술을 적용하고자 하는 연구가 진행중이다. 이러한 애드 혹 네트워크 구성의 핵심은 라우팅 프로토콜로써 본 논문에서는 송신자와 수신자 위성간의 교차지점을 활용한 라우팅 프로토콜을 제안한다. 제안된 방법은 시뮬레이션을 통하여 성능을 평가하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.1
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• pp.93-100
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• 2012

A telemetry signal occurs the line-of-sight problem by the effect of geography in flight test. A fixed relay system or a mobile relay system is used to solve that problem in general but we propose an airborne telemetry relay system using aircraft in this paper. An airborne telemetry relay system receives the telemetry signal of the test vehicle and then retransmits it to the ground system. The receiving antenna which is a phased array antenna can be tilted to ${\pm}30^{\circ}$ beam direction by beam-forming and track the rapidly moving test vehicle in effect. The relay pod which is mounted to an aircraft consists of the front antenna and the side antenna. It receives S-band signal and then down-converts the frequency to L-band signal. As a result, that can remove the frequency interference on an aircraft while retransmitting.