• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.915-918
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• 2000

In this paper, we propose an efficient feature vector extraction and decision fusion methods for the automatic classification of power system disturbances. Here, FFT and WPT(wavelet packet transform) are und to extract an appropriate feature for classifying power quality disturbances with variable properties. In particular, the WPT can be utilized to develop an adaptable feature extraction algorithm using best basis selection. Furthermore. the extracted feature vectors are applied as input to the decision fusion system which combines the decisions of several classifiers having complementary performances, leading to improvement of the classification performance. Finally, the applicability of the proposed approach is demonstrated using some simulations results obtained by analyzing power quality disturbances data generated by using Matlab.

• ETRI Journal
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• v.30 no.2
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• pp.216-226
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• 2008

This paper proposes a novel transport network architecture for the next generation network (NGN) based on the optical burst switching technology. The proposed architecture aims to provide efficient delivery of various types of network traffic by satisfying their quality-of-service constraints. To this end, we have developed a soft-state bandwidth reservation mechanism, which enables NGN transport nodes to dynamically reserve bandwidth needed for active data burst flows. The performance of the proposed mechanism is evaluated by means of numerical analysis and NS2 simulation. Our results show that the packet delay is kept within the constraint for each traffic flow and the burst loss rate is remarkably improved.

• Journal of applied mathematics & informatics
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• v.4 no.2
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• pp.535-543
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• 1997

The application of Hadamard matrix to the paral-lel routings on the hypercube network was presented by Rabin. In this matrix every two rows differ from each other by exactly n/2 positions. A set of n disjoint paths on n-dimensional hypercube net-work was designed using this peculiar property of Hadamard ma-trix. Then the data is dispersed into n packets and these n packet are transmitted along these n disjoint paths. In this paper Rabin's routing algorithm is analyzed in terms of covering problem and as-signment problem. Finally we conclude that n packets dispersed are placed in well-distributed positions during transmisson and the ran-domly selected paths are almost a set of n edge-disjoint paths with high probability.

• Journal of Korea Society of Digital Industry and Information Management
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• v.16 no.2
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• pp.27-33
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• 2020

Backward compatibility is one of the key issues for radio equipment supporting IEEE 802.11, the typical wireless local area networks (WLANs) communication protocol. For a successful packet decoding with the backward compatibility, the frame format detection is a core precondition. This paper presents a novel frame format detection method based on a deep learning procedure for WLANs affiliated with IEEE 802.11. Considering that the detection performance of conventional methods is degraded mainly due to the poor performances in the symbol synchronization and/or channel estimation in low signal-to-noise-ratio environments, we propose a novel detection method based on convolutional neural network (CNN) that replaces the entire conventional detection procedures. The proposed deep learning network provides a robust detection directly from the receive data. Through extensive computer simulations performed in the multipath fading channel environments (modeled by Project IEEE 802.11 Task Group ac), the proposed method exhibits superb improvement in the frame format detection compared to the conventional method.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.4
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• pp.288-291
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• 2002

We characterize multipath fading channel dynamics at the packet level and analyze the corresponding data queueing performance in various environments. We identify the similarity between wire-line queueing analysis and wireless network per-formance analysis. The second order channel statistics, i.e. channel power spectrum, is fecund to play an important role in the modeling of multipath fading channels. However, it is identified that the first order statistics, i.e. channel CDF also has significant impact on queueing performance. We use a special Markov chain, so-called CMPP, throughout this paper.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.331-334
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• 2005

This paper suggests the Ethernet aggregation to XGMII framing procedure (EAXFP) mechanism to economically combine the traffic adaptation technology with the link aggregation method in designing 10 Gigabit Ethernet (10 GbE) interfaces. This design sidesteps the data-loss issues that can result from designing an interface with only one link. The most critical issue in relation to the link aggregation interface is the algorithm used to control frame distribution between the ten ports. The proposed EAXFP mechanism offers an efficient link aggregation method as well as an efficient frame distribution algorithm, which maximize the throughout of the 10 GbE interface. In the experiment and analysis of the proposed mechanism, it was also discovered that the 10 GbE interface that uses the proposed EAXFP mechanism significantly reduced the packet loss rate. When there will be heavy traffic loads come about in the future, the proposed EAXFP mechanism assures an efficient and economical transmission performance on the router system.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.122-128
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• 2010

Efficient energy management is a very important issue in wireless sensor network since wireless sensor nodes are usually battery-powered. Recently, S-MAC protocol based on low duty-cycle has been proposed to reduce energy consumption. Even though research effort has been made to evaluate performance of S-MAC by conducting various simulations, however, some important simulation parameters are not well evaluated yet. In this paper, we identify the performance of S-MAC under different amount of streams and different patterns such as data rate and traffic. Through analyzing the simulation results, we discover weakness of S-MAC as well as analyze impact of amount of streams and packet pattern.

• Journal of information and communication convergence engineering
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• v.8 no.1
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• pp.71-76
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• 2010

Scalable video coding (SVC) has been standardized as an extension of the H.264/AVC standard. SVC allows straightforward adaptation of video streams by providing layered bit streams. In this paper, we propose a SVC video-based multicasting system preserving scalable security which is able to provide a SVC video service while maintaining information security. In order to maintain information security between a server and a client during all transmission time, the proposed system immediately performs a packet filtering process without decoding with respect to encrypted data received in a routing device, thereby reducing an amount of calculations and latency.

• Annual Conference of KIPS
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• 2017.11a
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• pp.126-127
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• 2017

사물인터넷 산업이 발전함으로써 차량 간의 통신이 주목 받고 있다. 네트워크 연결이 빈번하게 끊어지는 자동차 사이에서 무선으로 통신을 하기 위한 네트워킹에 대해 알아본다. 이를 위하여 차량이 노드 역할을 하는 VANET 환경에서 CCN을 적용하여 Data Packet 수를 살펴보았다.

• The Transactions of the Korea Information Processing Society
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• v.6 no.11S
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• pp.3332-3339
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• 1999

TCP protocol is originally designed for the wired network in which the packet loss in mostly caused the network congestion, and thus the performance of protocol can be decreased in mobile Internet environment due to the comparatively high error rate of wireless link. This paper analyzes the influence of retransmission interference that is a major factor to the TCP performance decrease. We first build a model in order to simulate the mobile Internet environment that includes the wireless network, and then we implement a program using PARSEC simulation language and finally executed the program. Based on the simulation results, we suggest a method that reduce the effect of the retransmission interference.