• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.1
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• pp.171-192
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• 2017

The change of any element in the network is possible to cause performance degradation of the multicast network. So it is necessary to optimize the topology path through the multicast update strategy, which directly affects the performance and user experience of the overlay multicast. In view of the above, a new multicast tree update strategy based on perturbation theory Musp (Multicast Update Strategy based on Perturbation theory) is proposed, which reduces the data transmission interruption caused by the multicast tree update and improves user experiences. According to the multicast tree's elements performance and the topology structure, the Musp strategy defines the multicast metric matrix and based on the matrix perturbation theory it also defines the multicast fluctuation factor. Besides it also demonstrates the calculability of the multicast fluctuation factor presents the steps of the Musp algorithm and calculates the complexity. The experimental results show that compared with other update strategies, as for the sensitivity of the multicast fluctuation factor's energized multicast tree to the network disturbance, the maximum delay of the Musp update strategy is minimal in the case of the local degradation of network performance.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.463-467
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• 2006

Several segmentation algorithms have been proposed for DTM generation or building modeling from airborne LiDAR data. Three components are important for accurate segmentation: (i) the adjacent relationship of n-nearest points or mesh, etc. (ii) the effective decision parameters of height, slope, curvature, and plane condition, (iii) grouping methods. In this paper, we created the topology of point cloud data using the contour tree and implemented the region-growing Terrain and non-terrain points were classified correctly in the segmented data, which can be used also for feature classification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.123-126
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• 2005

STP gets to have different network performance, depending on the configuration method of topology. Accordingly, for efficient network environment, it is necessary to make the optimum topology. This paper proposed a way to make the optimum topology for construction of efficient network among switches on ethernet: the optimum topology was made by calculating the time the switches in the same domain receive the frame transmitted from the root switch, using a mathematical model. And it analyzed the performance of the topology depending on the location of the root switch. As a result of analyzing the performance, this study came to the conclusion that it would be effective to locate the root switch in the center of the square network.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.9A
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• pp.874-881
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• 2010

Acoustic signal, which is a main carrier of underwater communication, attenuates along the traveled path heavily depending on the frequency as well as inter-node distance. In addition, since it has a long propagation delay, the conventional medium access control (MAC) schemes requiring complex signaling procedures and accordingly heavy overhead messages would not be appropriate in underwater communications. In this paper, we propose a code division multiple access (CDMA) scheme as a solution for MAC of underwater communication and evaluate the performance. A hierarchical data-gathering tree topology is considered and a staggered wake-up pattern is employed for the purpose of energy saving. As a performance measure, the data rate at each level of hierarchical topology is derived.

• The Transactions of the Korea Information Processing Society
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• v.6 no.2
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• pp.299-306
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• 1999

Considers the problem to update the spanning tree and strongly-connected components in response to topology change of the network. This paper proposes a distributed algorithm that solves such a problem after several processors and links are added and deleted. Its message complexity and its ideal-time complexity are O(n'log n'+ (n'+s+t)) and O(n'logn') respectively where n'is the number of processors in the network after the topology change, s is the number of added links, and t is the total number of links in the strongly connected component (of the network before the topology change) including the deleted links.

• The Journal of the Acoustical Society of Korea
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• v.21 no.2
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• pp.199-210
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• 2002

In this paper, we carried out the study on speech recognition using the KM-Net topology design algorithm based on decision tree state-clustering to improve the performance of acoustic models in speech recognition. The Korean has many allophonic and grammatical rules compared to other languages, so we investigate the allophonic variations, which defined the Korean phonetics, and construct the phoneme question set for phonetic decision tree. The basic idea of the HM-Net topology design algorithm is that it has the basic structure of SSS (Successive State Splitting) algorithm and split again the states of the context-dependent acoustic models pre-constructed. That is, it have generated. the phonetic decision tree using the phoneme question sets each the state of models, and have iteratively trained the state sequence of the context-dependent acoustic models using the PDT-SSS (Phonetic Decision Tree-based SSS) algorithm. To verify the effectiveness of the above algorithm we carried out the speech recognition experiments for 452 words of center for Korean language Engineering (KLE452) and 200 sentences of air flight reservation task (YNU200). Experimental results show that the recognition accuracy has progressively improved according to the number of states variations after perform the splitting of states in the phoneme, word and continuous speech recognition experiments respectively. Through the experiments, we have got the average 71.5%, 99.2% of the phoneme, word recognition accuracy when the state number is 2,000, respectively and the average 91.6% of the continuous speech recognition accuracy when the state number is 800. Also we haute carried out the word recognition experiments using the HTK (HMM Too1kit) which is performed the state tying, compared to share the parameters of the HM-Net topology design algorithm. In word recognition experiments, the HM-Net topology design algorithm has an average of 4.0% higher recognition accuracy than the context-dependent acoustic models generated by the HTK implying the effectiveness of it.

• Journal of Communications and Networks
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• v.15 no.6
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• pp.614-634
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• 2013

The proliferation of real-time multimedia services requires huge amounts of data transactions demanding strict quality-of-service (QoS) guarantees. Multicast transmission is a promising technique because of its efficient network resource utilization. However, high head-of-line (HOL) blocking probability and lack of service-specific QoS control should be addressed for practical implementations of multicast networks. In this paper, a topology aware fanout set division (TAFD) scheme is proposed to resolve these problems. The proposed scheme is composed of two techniques that reduce HOL blocking probability and expedite packet delivery for large-delay branches regarding multicast tree topology. Since management of global topology information is not necessary, scalability of the proposed scheme is guaranteed. Mathematical analysis investigates effects of the proposed scheme and derives optimal operational parameters. The evaluation results show that the TAFD scheme achieves significant delay reduction and satisfies required delay bounds on various multicast networks.

• Journal of information and communication convergence engineering
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• v.6 no.4
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• pp.383-390
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• 2008

Clock skew modeling is important in the performance evaluation and prediction of clock distribution network and it is one of the major constraints for high-speed operation of synchronous integrated circuits. In clock routing synthesis, it is necessary to reduce the clock skew under the specified skew bound, while minimizing the cost such as total wire length and delay. In this paper, a new efficient bounded clock skew routing method is described, which generalizes the well-known bounded skew tree method by allowing loops, i.e., link-edges can be inserted to a clock tree when they are beneficial to reduce the clock skew and/or the wire length. Furthermore, routing topology construction and wire sizing is used to reduce clock delay.

• Journal of Communications and Networks
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• v.8 no.1
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• pp.85-92
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• 2006

In this paper, we study a wireless cellular network design problem. It consists of selecting the location of the base station controllers and mobile service switching centres, selecting their types, designing the network into a tree-topology, and selecting the link types, while considering the location and the demand of base transceiver stations. We propose a constraint programming model and develop a heuristic combining local search and constraint programming techniques to find very good solutions in a reasonable amount of time for this category of problem. Numerical results show that our approach, on average, improves the results from the literature.

• Proceedings of the IEEK Conference
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• 2004.06a
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• pp.91-94
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• 2004

In this paper, we propose a new parallel computer topology, called the postorder Fibonacci circulants and analyze its properties. It is compared with Fibonacci cubes, when its number of nodes and its degree is kept the same of comparable one. Its diameter is improved from n-2 to [$\frac{n}{3}$] and a its topology is changed from asymmetric to symmetric. It includes Fibonacci cube as a spanning tree.