• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.12-13
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• 2003

광 솔리톤은 고속, 장거리 광통신시스템에서 분산과 self-phase modulation(SPM)에 의한 문제를 해결하기 위한 효과적인 기술 중의 하나이다. 현재, 솔리톤 전송은 장거리 해저 광전송시스템 뿐만 아니라 중거리 및 근거리 고속 전송시스템에서도 적용하기 위한 연구가 집중되고 있다. 특히, 솔리톤 전송은 광전중계기 없이 장거리 전송이 가능한 장점으로 인하여 기존의 중, 단거리링크를 초고속링크로 업그레이드하기 위하여 많은 연구가 진행되고 있다. (중략)

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.89-97
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• 2018

In future warfare, most part of resources and their platforms would be replaced by unmanned system like UGV(Unmanned Ground Vehicle). They are also connected each other with communication network and it is called NCW(Network Centric Warfare) environment. Hence how to measure the effectiveness of UGV operated in NCW circumstance become an important issue. However, there are few research paper to deal with this kind of UGV effectiveness issue coupled with communication failure. In this paper, we proposed a new ABM process to measure the UGV effectiveness combined with communication success ratio based on terrain condition of the ground engagement. Additionally, we also provide the effectiveness analysis result when communication repeater is applied in case of communication failure.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.6
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• pp.661-668
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• 2012

In this paper, a dual-fed small ICS repeater antenna with high isolation is designed, fabricated, and measured. Bandwidth and gain are optimized by changing the stub lengths near main patch and power divider, and also by changing the size of parasitic patch. To improve the isolation characteristic of the antenna, a dual-feeding method is applied in designing the antenna. The fabricated antenna has a VSWR less than 2, a gain over 7 dBi, and an isolation between the donor and the server antennas less than -65 dB from 1,920~2,170 MHz for 3G mobile communication.

• ETRI Journal
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• v.14 no.3
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• pp.1-15
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• 1992

Stand-slone 신호 중계 교환기인 SMX-1(Signalling Message eXchange No.1)은 통신망의 신경계인 공통선 신호망(Common Channel Signalling Network)의 하부 구조를 구성하는 시스팀이다. SMX-1에 총괄명 번역서비스를 수용하게 되면 통신망 사용자에게 통신망 내부의 구성 및 구성 요소의 변화에 구속되지 않고 지속적인 지능망 서비스를 제공할 수 있게 된다. 본 연구에서는 SMX-1의 설계 이념에 부합되도록 신호연결 제어부의 기능을 소프트웨어 및 하드웨어적으로 분산화하여 설계, 구현함으로써 SMX-1의 고신뢰성 및 신속성을 추구하였다. 소프트웨어적으로는 총괄명번역 서비스 제공을 위해 국제 전신 전화 자문 회의(CCITT)권고 Q.711-Q.714에서 정의하고 있는 신호연결 제어부(SCCP:Signalling Connection Control Part)의 기능을 관리 기능(SCMG : SCCP Management Part)과 루팅 제어 기능(SCRC : SCCP Routing Control Part)으로 분리하여 각각의 기능을 이중화하여 설계, 구현하였다. 하드웨어적으로는 관리 기능을 하나의 보드로 집중화하고 루팅 제어 기능을 여러개의 보드로 분산화하였다. 분산되어 있는 루팅 제어기능이 총괄명번역 서비스를 수행하기 위하여 사용하는 루팅 제어 데이터의 일치성을 유지하기 위하여, 관리 기능에 루팅 제어 데이터를 총괄적으로 관리하는 루팅 제어 데이터 관리 기능(RCDMFB : Routing Control Data Management Function Block)과 운용 관리 기능 (OMS : Operation and Management Subsystem)의 제원관리 지원기능을 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.595-597
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• 2005

현재 IP 멀티캐스트의 도입의 지연으로, 기존의 유니캐스트 망 기반 멀티캐스트의 필요성이 대두되어 오버레이(Overlay) 멀티캐스트 관련 연구가 진행 중이다. 특히, 확장성 제공과 작은 오버헤드 등으로 효율적인 CBT(Core Based Trees) 기반의 오버레이 멀티캐스트에 대한 연구가 활발히 진행 중이다. 그러나 기존의 거리 매트릭(Metric) 기반의 CBT로 오버레이 트리를 구성하는 경우, 특정 라우터에 패킷이 집중되는 현상으로 인하여 혼잡이 발생하여 멀티캐스트 성능 저하뿐만 아니라 네트워크 전체 성능을 저하시킬 수 있다. 본 논문에서는 이를 해결칠기 위하여. 코어 노드를 기준으로 이웃하는 두 노드 간의 패킷 중계 방향성을 계산하는 알고리즘을 제안하고. 이 결과값을 이용하는 새로운 매트릭 기반의 CBT를 구성하고자 한다. 실험 결과, CBT 상의 자식 위치에 있는 종단 노드로 패킷을 중계하는 과정에서 중복되는 패킷 전송 경로를 최소화하여 CBT를 구성함으로써 특정 라우터에 집중되는 트래픽을 줄이거나 다른 라우터로 트래픽을 분산함으로써 혼잡 발생 가능을 낮추어 보다 안정적인 통신을 기대할 수 있다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.5A
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• pp.441-450
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• 2007

In this paper, it is proposed the link performance analysis results using SNRAT(Satellite Network Resource Allocation & Analysis Tool) and verified the anticipated results by satellite communication network simulator. A communication satellite cannot be corrected or fixed for the error in orbit operation after launching unlike the ground operation equipment and has a restricted operation life. So, it is important to make possible to use satellite communications in the proper time. It is expected the link BER(Bit Error Rate), throughput and AJ(Anti-Jamming) performance using SNRAT tool before launching. And it is verified the performance of the repeaters and ground equipment specification using the satellite network simulator and is extracted the optimum operational scenarios through the tests of various network operational plans.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.4B
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• pp.388-396
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• 2002

In this paper, An aperture-coupled microstrip patch antenna operating at WLL frequency range(Rx : 2.3∼2.33Ghz, Tx : 2.37 ∼2.4Ghz) for WLL repeater is designed and fabricated. FR-4 epoxy substrate with 4.7 relative permittivity is inserted between feed-line and patch plane. Aperture-coupled structure is employed for consideration of bandwidth improvement and gain\`s characteristics. Air gap is arranged at each layer for bandwidth extension and radome is used as a protector in the upper patch. In this paper, both 1 port and 2 port are designed as 1$\times$2 array antenna which uses T-junction and λ$\_$g//4 transformer. Here, 1 port is used as transmitting/receiving antenna and 2 port is used as receiving antenna. Functionally independent two antennas using space diversity arrange slots between two antennas in order to be placed at the same place. As a result, we obtained a excellent isolation below -40dB and return loss is reduced by means of slots arrangement between patch and antenna.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.12 no.2
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• pp.43-52
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• 2012

This paper presents and analyzes laboratory test results of Interference Cancellation Digital On Channel Regenerative Repeater(IC-DOCR) to broadcast digital television signals in the Advanced Television Systems Committee(ATSC) transmission systems using single frequency networks(SFN). IC-DOCR laboratory test is classified to receiver test, transmitter test, and feedback interference cancellation test. The receiver part includes random noise, single echo, multi-path ensembles, and adjacent channel interference test. The transmitter part includes out-of channel emission, equality of transmitting signal, and phase noise test. By the laboratory test, the receiver part of the IC-DOCR eliminates 28dB of feedback signal higher than the received signal and has 17.8dB at TOV(Threshold Of Visibility) under random noise environment. Also, the transmitter part satisfies the specification of US FCC(Federal Communications Commission) as well as maintains good output signal quality for guaranteeing more than SNR 30dB.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.911-916
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• 2016

The nearest-neighbor multihop routing with/without infrastructure support is known to achieve the optimal capacity scaling in a large packet-erasure network in which multiple wireless nodes and relay stations are regularly placed and packets are erased with a certain probability. In this paper, a throughput scaling law is shown for an infrastructure-supported erasure network where wireless nodes are randomly distributed, which is a more feasible scenario. We use an exponential decay model to suitably model an erasure probability. To achieve high throughput in hybrid random erasure networks, the multihop routing via highway using the percolation theory is proposed and the corresponding throughput scaling is derived. As a main result, the proposed percolation highway based routing scheme achieves the same throughput scaling as the nearest-neighbor multihop case in hybrid regular erasure networks. That is, it is shown that no performance loss occurs even when nodes are randomly distributed.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.10 no.5
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• pp.424-434
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• 2017

In industrial wireless sensor networks, many applications require integrated QoS supporting. This paper proposes a reliable protocol for real-time monitoring in industrial wireless sensor networks. Retransmission is well-known to recover the transmission failure, however, this might cause the time delay to violate the real-time requirement. The proposed protocol exploits broadcasting feature of wireless networks and the temporal opportunity concept. The opportunities to relay the data packets are shared by the broadcasting feature and the temporal opportunity concept maximize the number of candidates in communication. Simulation results show that the proposed protocol is superior to the existing real-time protocols in term of real-time service and reliability.