• Journal of KIISE:Information Networking
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• v.28 no.1
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• pp.173-181
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• 2001

최근 인터넷 사용자의 증가와 서비스의 다양화 그리고 이에 따른 고속 인터넷 엑세스 기술의 도입으로 인터넷 트래픽의 급격한 증가를 초래하고 있다. 이러한 이유로 인터넷 패킷 전달에 2계층 스위칭 기술과 3계층 라우팅 기술을 접목한 IP/ATM Hybrid system이 등장하게 되었다. 이러한 시스템에서의 중요한 자원은 2계층 스위칭 기술을 사용하기 위한 유한한 VCI/VPI 공간이다. 이 VCI/VPI 공간을 효과적으로 관리하기 위한 방안으로 많은 방안들이 제시되고 있다. 특히 흐름 기반의 IP/ATM Hybrid system에서의 흐름 분류기를 사용함으로서 VCI/CPI 공간을 관리하고 있다. 본 논문에서 주장하는 적응형X/Y 분류기가 유한한 VCI/VPI 공간을 효율적으로 관리하기 위한 방안임을 제시하고 이에 대하여 실험을 통하여 성능 평가를 실시하였다 특히 동일한 VCI/VPI 공간에서 X/Y분류기와의 비교실험에서 적응형 X/Y 분류기의 성능이 높은 스위칭 율로 나타나고 있다. 즉 적응형 X/Y 분류기가 X/Y분류기에 비하여 효율적으로 VCI/VPI를 관리함을 보이고 있다

• Proceedings of the Korea Information Processing Society Conference
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• 2000.10b
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• pp.1267-1270
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• 2000

위성통신 시스템은 기존의 지상망이나 광 케이블 기술에 비해 통신 대역폭의 유연성과 다중 접속능력, 이동통신, 광역성, 멀티포인트 및 브로드캐스팅 등의 본래의 특징으로 인해 초고속정보통신망 구축에 중요한 역할을 하게 된다. 특히 OBP (On-Board Processing) 기술을 적용하면 기존 위성통신 탑재장치의 수동적인 중계 기능 이외에 복조/재변조, 부호/복호화 및 오류정정, 중계기 및 빔간의 상호 연결/절체 등의 새로운 기능이 추가되어 능동적인 중계를 가능하게 함으로써 통신 품질의 향상, 통신 링크의 전송 효율 개선, 전송 용량 증대 등의 장점을 갖고있다. OBP 탑재 위성 B-IDSN 중계망은 하나의 거대한 가상 ATM 교환기로 간주되고, 여러중계 지구국들중 목적 중계 지구국으로 패킷들을 직접 라우팅 할 수 있는 장점이 있다. 본 논문은 OBP 탑재 위성 B-ISDN 연동 프로토콜 연구를 수행하는 것으로서, 위성 B-ISDN 구조와 각 지구국별 신호 기능 및 B-IDSN 신호 시스템인 DSS2 계층 3 신호 프로토콜, B-ISUP 프로토콜, S-BISUP 프로토콜의 구조를 분석하였다. 또한 점-대-다지점을 위한 B-ISDN의 연결과 소유권 및 각각의 프로토콜에 대한 메시지와 프리미티브를 정의하여, 이를 토대로 OBP 탑재 위성 B-IDSN 연동 프로토콜의 기본 호 처리 절차를 설계 및 구현하고, 이를 테스트하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.10C
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• pp.980-986
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• 2002

In the fast data communication system, synchronized by a clock source, the loss of data will often occur due to several reasons as a differential routing path between data and clock, a differential propagation delay of components or an unstable phase of clock and data by external noise. In this paper, we describe the ASIC implementation of the data compensation circuit which can detect the data loss from above problems and recovery to original data with stable synchronization. Especially it supports a strong stability and a good BER in the communication system for fast data transfer as optic area. This circuit is implemented by Verilog HDL and available to the digital ASIC implementations related to fast data transfer.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.590-593
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• 2011

Time goes on, Ad Hoc network is hot issues. So far, there are a lot of protocols have been proposed for Ad Hoc routing protocol to support the mobility. This paper presents an enhanced DSDV(Destination-Sequenced Distance Vector) routing protocol which nominates one node to take care of a specific area. Simply Area-Aware(AA) DSDV routing protocol has one nominee to take care of some area. It has two jobs. One is to take care of its neighbour and another is to transfer the routing table to its other node as it works. It is called as Area Nominee(AN). The new scheme extends the routing table to include the nominee in the area. The general node is the same as the previous DSDV routing protocol. In the other hands, the node which is nominated has two routing protocols. One is for Regional Routing(RR) table which is the same routing table in DSDV. Another is Global Routing(GR) table which is about the area round its area which it cares nearby. GR table is the table for the designated node like the nominee. Each area has one nominee to transfer between ANs. It has only nominee's information about every area. This concept decreases the topology size and makes the information of topology more accurate.

• The Transactions of the Korea Information Processing Society
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• v.2 no.4
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• pp.592-602
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• 1995

Non-grid and grid method are used for modeling the routing region of the automatic routing system. In this study, we develop the automatic routing system by mixing the methods of non-grid and grid to improve the speed of routing. Grid method has a demerit which decreases the automatic routing speed because it is required a lot of memory by the limitation of the size of board and grid, although the electrical and physical elements are insufficient on the PCB, But non-grid is spent gurite less memory than grid method by using a shape-based patterns. Therefore, we used the methods of non-grid and grid altogether in this paper, In the former method, it is attributed to the improvement of speed, the latter one is applied only the connection of the failed routing in the former one, and it performs the complete automatic routing. This system was developed with C＋＋language under the Windows NT environment of IBM 486DX2-66 Computer.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.6
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• pp.1391-1396
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• 2011

A way to increase productivity in agriculture that is labor-centered industry is to graft IT technology. Today, many technologies in ubiquitous computing are deployed in all areas of society such as traffic control, automotive manufacturing, construction, defence, healthcare and clinical services. These IT technologies is gaining more attention as a fusion technology among traditional industries. To successfully build ubiquitous agriculture environment, it needs optimized core technology development for agriculture that includes sensor node H/W, middleware platform, routing protocol and agriculture environment application services. To achieve accurate botany growth environment management, we propose a green growth environment management system using environmental factor monitoring sensor and biological information sensors in greenhouse. By using our proposed system, it is expected to realize fusion complex agriculture technology with low cost.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3B
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• pp.144-152
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• 2005

Mobile IP(MIP) and SIP have been proposed to support mobility in the wireless internet working at different layers of the protocol stack. However MIP has some problems such as triangle routing, the need of each host's home address, the overhead of tunneling and the lack of wide deployment. Thus we proposed a scheme for supporting mobility based on SIP in this research. A novel SIP system to provide a hierarchical registration has been designed according to this scheme. Our SIP system has been established by implementing JAIN technologies which follow next generation network standards to support the mobility of wireless terminal. This system successfully satisfied ITU-T recommendation.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.47 no.2
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• pp.1-10
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• 2010

Mapping virtual process topology to physical processor topology is one of the most important design issues in parallel programming. However, the mapping problem is complicated due to the topology irregularity and routing complexity. This paper proposes a new process mapping scheme called adjacency-based mapping (AM) for irregular cluster systems assuming that the two-dimensional mesh process topology is specified as an interprocess communication pattern. The cluster systems have been studied and developed for many years since they provide high interconnection flexibility, scalability, and expandability which are not attainable in traditional regular networks. The proposed AM tries to map neighboring processes in virtual process topology to adjacent processors in physical processor topology. Simulation study shows that the proposed AM results in better mapping quality and shorter interprocess latency compared to the conventional approaches.

• The KIPS Transactions:PartD
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• v.11D no.4
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• pp.975-982
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• 2004

In current P2P concept, pure P2P and Hybrid P2P structures are used commonly. Gnutella and Ktella are forms of pure P2P. and forms of Hybrid P2P are innumerable. File searching models exist in these models. These models provide group management for file sharing, searching and indexing. The general file sharing model is good at maintaining connectivity. However, it is defective in group management. Therefore, this study approaches hierarchical structure in file sharing models through routing technique and backup system. This system was designed so that the user was able to maintain group efficiency and connection reliability in large-scale network.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.622-628
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• 2016

The prosperity of IT technologies and the removal of restrictions regarding Unmanned Aerial Vehicles (UAVs), also known as drones, have driven growth in their popularity. However, without a proper solution to the problem of accident avoidance for UAVs, this popularity increases the potential for collisions between UAVs and between UAV and terrain features. These collisions can occur because UAVs to date have flown using radio control or image recognition based autonomous navigation. Therefore, we propose efficient UAV routing schemes to tackle the collision problem using vehicular communication systems. Performance evaluation by computer simulation shows that the proposed methods effectively reduce the collision probability and improve the routing efficiency of the UAV. Furthermore, the proposed algorithms are compatible and can be directly applied with small overhead to the commercial vehicular communication system implementation.