• Proceedings of the Korean Information Science Society Conference
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• 2000.04a
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• pp.707-709
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• 2000

본 논문은 광네트워크(optical network)에서 정보의 송/수신에 필요한 광경로를 설정하기 위한 방법으로 유전자 알고리즘을 이용한 라우팅 전략을 제시하고 있다. 논문에서 제시하는 유전자 알고리즘(genetic algorithms)은 메쉬형(mesh-like)광 네트워크의 각 링크에 적은 수의 광경로(lightpath)가 통과하도록 하여 네트워크 전체 링크의 사용빈도를 감소시키고 광경로들이 특정 링크로 집중되는 현상을 감소시켜 네트워크의 효율을 증가시키는 라우팅 전략을 제시할 수 있음을 보이고 있다.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.1264-1266
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• 2009

We introduce a location-based routing model applied for grid backbone nodes in wireless mesh network. The number of paths with nearest distance between two nodes is calculated and used as key parameter to execute routing algorithm. Node will increase the transmission range that makes a trade off with data rate to reach its neighbors when node itself is isolated. The routing model is lightweight and oriented thanks to the simple but efficient routing algorithm.

• Journal of Electrical Engineering and information Science
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• v.1 no.1
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• pp.98-107
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• 1996

In this paper, we propose a scheme that maps the time-delay neural network (TDNN) into the neurocomputer called EMIND-II which has the wavefront toroidal mesh-array structure. This neurocomputer is scalable, consists of many timeshared virtual neurons, is equipped with programmable on-chip learning, and is versatile for building many types of neural networks. Also we define the programming model of this array and derive the parallel algorithms about TDNN for the proposed neurocomputer EMIND-II. In addition, the computational complexities for the parallel and serial algorithms are compared. Finally, we introduce an application of this neurocomputer to word recognition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.5
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• pp.1116-1121
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• 2014

Mesh structure is one of typical interconnection networks, and it is used in the part of VLSI circuit design. Torus and Hyper-Torus are advanced interconnection networks in the part of diameter and fault-tolerance of mesh structure. In this paper, we will analyze embedding between Torus and Hyper-Torus networks. We will show T(4k,2l) can be embedded into QT(m,n) with dilation 5, congestion 4, expansion 1. And QT(m,n) can be embedded into T(4k,2l) with dilation 3, congestion 3, expansion 1.

• ETRI Journal
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• v.27 no.4
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• pp.355-366
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• 2005

Automatic discovery of physical topology plays a crucial role in enhancing the manageability of modern metro Ethernet networks. Despite the importance of the problem, earlier research and commercial network management tools have typically concentrated on either discovering logical topology, or proprietary solutions targeting specific product families. Recent works have demonstrated that network topology can be determined using the standard simple network management protocol (SNMP) management information base (MIB), but these algorithms depend on address forwarding table (AFT) entries and can find only spanning tree paths in an Ethernet mesh network. A previous work by Breibart et al. requires that AFT entries be complete; however, that can be a risky assumption in a realistic Ethernet mesh network. In this paper, we have proposed a new physical topology discovery algorithm which works without complete knowledge of AFT entries. Our algorithm can discover a complete physical topology including inactive interfaces eliminated by the spanning tree protocol in metro Ethernet networks. The effectiveness of the algorithm is demonstrated by implementation.

• Journal of Communications and Networks
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• v.6 no.1
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• pp.46-59
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• 2004

In this paper, we present two algorithms for efficiently aggregating link state information needed for quality-of-service (QoS) routing. In these algorithms, each edge node in a group is mapped onto a node of a shufflenet or a node of a de Bruijn graph. By this mapping, the number of links for which state information is maintained becomes aN (a is an integer, N is the number of edge nodes) which is significantly smaller than N2 in the full-mesh approach. Our algorithms also can support asymmetric link state parameters which are common in practice, while many previous algorithms such as the spanning tree approach can be applied only to networks with symmetric link state parameters. Experimental results show that the performance of our shufflenet algorithm is close to that of the full-mesh approach in terms of the accuracy of bandwidth and delay information, with only a much smaller amount of information. On the other hand, although it is not as good as the shufflenet approach, the de Bruijn algorithm also performs far better than the star approach which is one of the most widely accepted schemes. The de Bruijn algorithm needs smaller computational complexity than most previous algorithms for asymmetric networks, including the shufflenet algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.7
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• pp.1465-1470
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• 2011

In this paper, we propose a new MAC protocol, namely DM-MMAC (Doze Mode Multi-Channel MAC) for ad hoe wireless networks which can utilize multiple channels effectively, thereby enhancing the network throughput considerably. Basically, the IEEE 802.11 specification allows for the use of multiple channels available at the physical layer, but its MAC protocol is designed only for a single channel with the fatal drawback, so called multi-channel hidden terminal problem in multi-channel environments. In this vein, several multi-channel MAC protocols have been proposed, but most of them demonstrate the performance problem that its throughput drastically decreases as the number of mobile hosts residing in a given network increases with small number of available channels. In this work, we tried to improve the performance of multi-channel MAC protocols in terms of network throughput as well as power saving effects by simplifying the channel assignment and channel capturing procedures and reducing the possibility of collisions between mobile hosts.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.3
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• pp.341-345
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• 2010

WMN is one of efficient solutions to provide Internet services for users by forming wireless backbone networks with wireless links. The dominant technology for WMNs is the IEEE 802.11, which provides multi-channel and multi-rate capabilities. One of important issues in WMNs is the network capacity and it is essential to design a multi-channel protocol that leverages the network capacity. However, when wireless links that use different data rates operate on the common channel, the performance of high-rate links is severely degraded by the presence of the low-rate links, which is often referred as performance anomaly. In this paper, we propose a Tree-based Channel Assignment (TreeCA) protocol to mitigate the performance anomaly problem by distributing data rates over multiple channels. TreeCA performs channel assignments based on the tree WMN architecture to accommodate the Internet traffics efficiently. Parent nodes on the tree distribute their child nodes over multiple channels so that the performance anomaly is reduced. Through simulations, we observed that the proposed TreeCA outperforms the existing multi-channel protocols for WMNs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.1A
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• pp.17-24
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• 2012

In this paper, we described a received signal model in terms of the starting point of FFT window and derive a post-detection SINR for the receiver with MMSE filter and the corresponding filter coefficients in order to mitigate the effects of interferences caused by time and frequency selective fading channels and time difference of arrival (TDoA) in OFDMA-based Mesh Networks. In addition, we proposed an MMSE Bidirectional Successive Detection (BSD) technique which can suppress the effects of interferences among multi-nodes without any redundant FFT operations. It was shown by simulation that the proposed interference suppression technique has not an error floor at higher average SNR than 30dB in terms of 64QAM uncoded BER contrary to the conventional techniques.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37B no.12
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• pp.1174-1185
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• 2012

This paper proposes a call admission control scheme for delay guarantee in the wireless mesh networks. The admission of a new call is determined based on the expected delay inferred from the class level available bandwidth at nodes on the path. All nodes under the effects of the new call are considered in designing the call admission control scheme to maintain the delay guarantee of the pre-existing traffic. An effective technique for estimating the available bandwidth of the neighbor nodes is proposed with no addition of message interchanges. The class-level delay control is mainly performed by the queueing discipline while keeping the MAC operation simple. Simulations are performed to show the validity of the proposals. We observe acceptable performances in delay expectation with the addition of new calls. We also show that the proposed call admission control is helpful in guaranteeing the delay performances.