• 한국경영과학회지
• /
• 제26권1호
• /
• pp.33-44
• /
• 2001

In this paper, we address a problem of traffic grooming and wavelength routing in all optical WDM ring networks. Given a traffic demand for each node pair, we should aggregate the traffic onto lightpaths between pairs of nodes to transport the demand, and set up the routing path for each lightpath with minimum number of wavelengths to be assigned to lightpaths. In this paper, we formulate our problem as a mixed Integer Programming model. Owing to the problem complexity, it is hard to find an optimal solution for our problem. hence, we develop a heuristic algorithm to solve our problem efficiently. From the computational experiments, we can find the proposed heuristic is very satisfactory in both the computation time and the solution quality generated.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2002년도 춘계학술대회 논문집
• /
• pp.535-542
• /
• 2002

This paper show communication network scheme problem for the railway is solved which were electrical noise and line break in wayside using rerouting communication line, Considering the availability and the maintainability based on the reliability in design of communication networks. At first, Self-Healing Ring algorithm is suggested in that solution which is satisfied with above requirements. And also, in the advanced type, Dual Master scheme is suggested that the problem which is occurred in line break of both main and sub line at the same time can be solved using DMSHR(Dual Master Self Healing Ring). Therefore total reliability in railway system is going to be advanced using DMSHR scheme.

• 한국정보처리학회:학술대회논문집
• /
• 한국정보처리학회 2004년도 춘계학술발표대회
• /
• pp.1259-1262
• /
• 2004

Detecting environmental hazards and monitoring remote terrain are among many sensor network applications. In case of fire detection, it is significantly valuable to monitor fire-spot's shape and trend in time. Mobile ad hoc sensor nodes right round are responsible for sensoring, processing and networking packets, or even launching extinguisher. In this paper, we proposed a ring-oriented Multicast architecture based on "Fisheye State Routing" (MFSR) to organize a group of mobile ad hoc sensor nodes in a multicast way. It is familiar with traditional mesh-based multicast protocol [1] in mobile ad hoc network, trying to concentrates on efficiency and robustness simultaneously. Certain applications-based solution for hazards is proposed, quantitative results including architecture and recovery algorithms of MFSR are also investigated in this paper.

• 에너지공학
• /
• 제14권2호
• /
• pp.112-116
• /
• 2005

본 논문에서는 높은 대역폭과 안정성을 제공하는 DCS용 통신망의 구조를 제시하고 성능을 해석한다. 본 논문에서 제시하는 DCS용 통신망은 DCS 통신망에서 널리 사용되는 리플렉티브 메모리 (Reflective Memory) 구조를 채용하며, 이에 따라 링형 토폴로지를 가진다 물리계층으로 사무용 및 산업용으로 널리 쓰이고 있는 패스트 이더넷(Fast Ethernet)물리 매체를 사용하여 100 Mbps의 대역폭을 가지고, 링형 토폴로지가 가지는 단점인 각 노드에서의 시간 지연을 줄이기 위해 RED(Ring Enhancement Device)라는 장치를 고안하여 사용한다. 본 논문에서 소개하는 DCS용 통신망을 ERCNet(Ethernet based Real-time Control Network)이라고 명명하며, ERCNet의 구조와 동작에 대해 설명한다. ERCNet의 통신 성능에 대한 수학적 해석을 수행하고 개발된 ERCNet을 이용한 실험을 통하여 해석 결과의 정확성과 통신망 성능을 검증한다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
• /
• pp.161-164
• /
• 2002

This paper presents an 1-D substrate resistance value expression and compares the measured wave-form data with the calculated 1-D resistance network model. The remaining part is devoted to the effectiveness of guard ring varying its width and number.

• 한국인터넷방송통신학회논문지
• /
• 제12권5호
• /
• pp.197-203
• /
• 2012

본 논문에서는 광파장다중화(WDM) 기반 광인터넷 환경에서 논리적인 다중 링 구조에 의한 통신망 복구 기법의 대역폭 효율성을 연구한다. 이 방법은 링 토폴로지의 특성을 이용해 빠르고 간단한 복구 동작을 제공하며, 지역적인 복구를 수행한다. 동시에 다중 링 구성을 통하여 대체 경로의 분산과 공유 정도를 높이고 단위 링크당 예약되어야 하는 예비 광파장의 수를 줄임으로써 전체 통신망 자원 이용의 효율성을 높일 수 있다. 본 논문에서는 위험공유링크그룹(SRLG) 개념을 이용하여 링크 손실을 복구하는데 필요한 예비대역폭 비율을 토폴로지상의 Cut-Set을 이용해 계산하고 이를 실험을 통해 비교 확인하였다.

• 한국통신학회논문지
• /
• 제30권8A호
• /
• pp.688-696
• /
• 2005

본 논문에서는 위성을 이용한 디지털 위성방송 시스템에 적용하기 위한 고효율 평면안테나를 설계 및 제작하였다. 전통적인 접시형 안테나에 비하여 높은 개구효율, 용11한 설치 및 미려한 외관 등의 장점을 가지고 있는 평면 안테나를 설계하였다. 안테나 소자의 설계에는 마이크로스트립을 이용한 Annular Ring 공진기를 이용하였으며, 방사형 도파관을 이용한 급전구조를 채택하였다. 또한 수신신호를 중간주파 신호로 변환하기 위한 LNB를 안테나의 뒷면에 설치함으로써 전송손실의 최소화를 꾀하였다. 제작된 안테나는 직경 35cm, 이득은 31.8dBi 이며 개구효율은 약 $80\%$이다.

• Journal of Communications and Networks
• /
• 제5권3호
• /
• pp.249-257
• /
• 2003

Ring networks are very commonly exploited among local area and metropolitan area networks (LAN/MAN), whereas cells or small fixed-size packets are widely used in synchronized ring networks. In this paper, we present an analytical method for evaluating the delay-throughput performance of a MAC protocol with multiple self-tokens in a slotted ring network under uniform traffic. In our analysis, we introduce the stationary probability, which indicates the number of packets in a node. Also, it is assumed that each node has a sufficiently large amount of self-tokens, and a slotted ring has the symmetry. The analytical results with respect to delay-throughput performance have similar values to computer simulated ones. Furthermore, in order to achieve fair access under non-uniform traffic, we propose an adaptive MAC protocol, where the number of self-tokens in a node dynamically varies, based on the number of packets transmitted within a specified period. In the proposed protocol, when the number of packets transmitted by a node within a specified period is larger than a specified threshold, the node decreases the number of self-tokens in a per-node distributed method. That results in creating free slots in the ring, thus all nodes can obtain an equal opportunity to transmit into the ring. Performance results obtained by computer simulation show that our proposed protocol can maintain throughput fairness under non-uniform traffic.

• 한국경영과학회:학술대회논문집
• /
• 대한산업공학회/한국경영과학회 2004년도 춘계공동학술대회 논문집
• /
• pp.135-138
• /
• 2004

This paper considers a ring loading problem on RPR(Resilient Packet Ring), where RPR is recommended by IEEE802.17 Resilient Packet Ring working group for data optimized networks without the requirements of provisioning circuits. RPR is well suitable for metropolitan area network with two counter-rotating rings that multiple stations share the bandwidth, where the data and its corresponding control traffic is transmitted to the two opposite directional ring, respectively. One of the major concerns on RPR is to provide fairness among traffic requirements. The paper discusses several fairness measures and analysis ring loading problems for the fairness.

• 한국경영과학회지
• /
• 제39권1호
• /
• pp.13-27
• /
• 2014

In this paper, we deal with a Steiner Ring Star (SRS) problem arising from the design of survivable telecommunication networks. We develop two mixed integer programming formulations for the SRS problem by implementing Miller-Tucker-Zemlin (MTZ) and Sarin-Sherali-Bhootra (SSB) subtour elimination constraints, and then apply the reformulation-linearization technique (RLT) to enhance the lower bound obtained by the LP relaxation. By exploiting the ring-star structure of underlying network, we devise some valid inequalities that tighten the LP relaxation. Computational results demonstrate the effectiveness of the proposed solution procedure.