• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.334-337
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• 2005

This paper describes the implementation of DCS communication network that provides high bandwidth and reliability. The network for DCS in this paper adopts the Reflective Memory (RM) architecture and Fast Ethernet physical media that have 100Mbps bandwidth. Also, this network uses Ring Enhancement Device (RED) which was invented to reduce the time delay of each node. The DCS network that is introduced in this paper is named as ERCNet(Ethernet based Real-time Control Network). This paper describes the architecture and working algorithms of ERCNet and performs numerical analysis. In addition, the performance of ERCNet is evaluated by experiment using the developed ERCNet network.

• Journal of Korean Society for Quality Management
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• v.28 no.1
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• pp.105-118
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• 2000

In this paper, we consider an interconnection network, DRDT (Dual Receive Dual Transmit), that is a double-loop ring topology and adopts the concept of multiple packets transmission. For three types of DRDT configurations, we investigate some properties related to path sets and discuss the method for finding minimal path sets. Using the concept of the terminal reliability and the path sets approach, we evaluate the reliability of the DRDT networks and compare them with a single ring network and a unidirectional double-loop ring network.

• Current Optics and Photonics
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• v.2 no.1
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• pp.23-26
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• 2018

Optical-layer restoration has been demonstrated with a wavelength-blocker (WB) -based reconfigurable optical add/drop multiplexer (ROADM). Two $2{\times}2$ optical switches with a control circuit were placed before and after a WB-based ROADM to provide automatic path restoration under fiber-failure conditions. Using the proposed node configuration, a 3-node self-healing ring (SHR) network has been implemented to demonstrate the feasibility of the automatic optical-layer restoration. From the results, the restoration time was measured to be ~4 ms under fiber-failure conditions, without any additional power penalty in receiver sensitivity.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.41 no.5
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• pp.1-7
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• 2004

A regular logical topology requires little processing time for routing purposes which may be a desirable property for high-speed networks. Asymmetric bilayered ShuffleNet, proposed by us as a logical topology, can be used to a wavelength division multiplexing ring network to increase the network capacity compared to ShuffleNet. In this paper, asymmetric bilayered ShuffleNet is imbedded on a wavelength division multiplexing ring with the objective of minimizing the total number of wavelengths assigned.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.891-900
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• 2005

This paper studies network recovery methods for WDM optical mesh networks, concentrating on improving spare resource utilization. The resource efficiency can be obtained by sharing spare resources needed for network recovery. To improve the sharability of spare resources in WDM networks, methods to share backup paths us well as spare capacity should be studied. The proposed method in this paper uses multiple ring-covers and this method provides fast and simple recovery operation by exploiting the characteristics of logical ring topology, and also provides efficient resource utilization by using multiple distributed backup paths to improve the sharability of overall spare resources in the networks. This method can provide layered reliability to network service by enabling hierarchical robustness against multiple failures. The performance results show that the proposed method provide improved resource efficiency for single failure and enhanced robustness for multiple failures.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.1
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• pp.157-176
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• 2011

An interest-based P2P constructs the peer connections based on similarities for efficient search of resources. A clustering technique using peer similarities as data is an effective approach to group the most relevant peers. However, the separation of groups produced from clustering lowers the scalability of a P2P network. Moreover, the interest-based approach is only concerned with user-level grouping where topology-awareness on the physical network is not considered. This paper proposes an efficient scalable search for the interest-based P2P system. A scalable multi-ring (SMR) based on fuzzy clustering handles the grouping of relevant peers and the proposed scalable search utilizes the SMR for scalability of peer queries. In forming the multi-ring, a minimized route function is used to determine the shortest route to connect peers on the physical network. Performance evaluation showed that the SMR acquired an accurate peer grouping and improved the connectivity rate of the P2P network. Also, the proposed scalable search was efficient in finding more replicated files throughout the peer network compared to other traditional P2P approaches.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.6
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• pp.1045-1054
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• 2020

In this paper, we designed a TCP/IP based ring buffer system that can stably transfer bulk data streams in the unstable network environments. In the scheme we proposed, The observation data stream generated and output by each radio observatory's backend system as a UDP frame is stored as a UDP packet in a large capacity ring buffer via a socket buffer in the client system. Thereafter, for stable transmission to the remote destination, the packets are processed in TCP and transmitted to the socket buffer of server system in the correlation center, which packets are stored in a large capacity ring buffer if there is no problem with the packets. In case of errors such as loss, duplication, and out of order delivery, the packets are retransmitted through TCP flow control, and we guaranteed that the reliability of data arriving at the correlation center. When congestion avoidance occurs due to network performance instability, we also suggest that performance degradation can be minimized by applying parallel streams.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.306-310
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• 2004

In this paper, we consider the Ring Loading Problem with integer demand splitting (RLP). The problem is given with a ring network, in which a required traffic requirement between each selected node pair must be routed on it. Each traffic requirement can be routed in both directions on the ring network while splitting each traffic requirement in two directions only by integer is allowed. The problem is to find an optimal routing of each traffic requirement which minimizes the capacity requirement. Here, the capacity requirement is defined as the maximum of traffic loads imposed on each link on the network. We formulate the problem as an integer program. By characterizing every extreme point solution to the LP relaxation of the formulation, we show that the optimal objective value of the LP relaxation is equal to p or p+0.5, where p is a nonnegative integer. We also show that the difference between the optimal objective value of RLP and that of the LP relaxation is at most 1. Therefore, we can verify that the optimal objective value of RLP is p+1 if that of the LP relaxation is p+0.5. On the other hand, we present a strengthened LP with size polynomially bounded by the input size, which provides enough information to determine if the optimal objective value of RLP is p or p+1.

• The KIPS Transactions:PartC
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• v.11C no.7 s.96
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• pp.895-904
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• 2004

Due to the frequent and unpredictable topology changes, multicast still remains as challenge and no one-size-fits-all protocol could serve all kinds of needs in mobile ad hoc network. In this paper, we propose a novel scheme of Hierarchical Eulerian Ring Oriented Multicast Architecture (HEROMA) over mobile ad hoc network. It has features that concentrate on efficiency and robustness simultaneously. It is also an application-driven proposal for hazard detection. Architectures including Eulerian ring, hierarchy and multicast agent are investigated in detail Simulation results different level of improvements on control traffic, end-to-end delay and packet delivery ratio by comparing with tree-based and mesh-based multicast protocols.

• The KIPS Transactions:PartC
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• v.13C no.4 s.107
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• pp.447-454
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• 2006

An ad-hoc network routing protocol, AODV(Ad-hoc On-demand Distance Vector) initially uses ERS(Expanding Ring Search) algorithm to control the RREQ(Route Request) retransmission in the route discovery process. Because ERS uses the fixed NTT(Node Travesal Time), it does not reflect accurately ad-hoc network environment. In this paper, we propose an improved ERS algorithm which lowers the retransmission rate. It uses RREP(Route Reply) and gives different weights in NTT of each node in accordance with the adjacency to an originating node. To show the effectiveness of the proposed algorithm, we perform a simulation using ns2. The simulation results showed that the proposed algorithm has better performance than existing algorithms.