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Effect of wavelength shift on PLC-type WDM directional coupler by UV irradiation

IEEE PHOTONICS TECHNOLOGY LETTERS 2000年第9期12卷 1189-1191页

作者： Han, SP Park, T Park, JS Jeong, KT Elect & Telecommun Res Inst Interconnect Team Taejeon 305350 South Korea Korea Telecom Access Network Lab Opt Commun Res Team Taejeon 305348 South Korea

The UV light of KrF excimer laser, which is used for making fiber gratings, is irradiated on PLC-type WDM directional couplers, After the irradiation, the shift of transmission wavelengths is observed as a function of UV exposure dose,The amount of the effective refractive index change of rectangular silica waveguides is calculated by the coupled mode theory and the measured data.

关键词： directional coupler KrF excimer laser planar lightwave circuit wavelength division multiplexing WDM coupler

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ANALYSIS OF OUT-OF-SEQUENCE PROBLEM AND PREVENTATIVE SCHEMES IN PARALLEL SWITCH ARCHITECTURE FOR HIGH-SPEED ATM NETWORK

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IEE PROCEEDINGS-COMMUNICATIONS 1994年第1期141卷 29-38页

作者： JUNG, YC UN, CK RYU, SM LEE, SC AGCY DEF DEV CTR COMMUN & ELECTR R&DTAEJON 300600SOUTH KOREA KOREA TELECOM TELECOMMUN NETWORK RES LABSEOUL 137140SOUTH KOREA

The parallel switch architecture combines advantageously a parallel plane method with a bit-parallel conversion scheme in VLSI implementation of ATM switches with the capability of handling unlimited external trunk speed. However, the parallel architecture encounters out-of-sequence problems owing to various possible switching paths. The authors analyse the out-of-sequence performance dependency on the trunk utilisation, the total number of virtual channels/trunk, and the number of parallel switch planes. They then propose two parallel switches equipped with preventive schemes for avoiding cells delivered out-of-sequence. By using the method of cascading virtual channel routing networks at input lines of the switch planes, the large speed reducing effect to support trunks at speeds of several Gb/s can be achieved in ATM-based parallel switch design. Also, the out-of-sequence problem is basically eliminated, and additional delay can be reduced to a negligible level.

关键词： HIGH SPEED ATM SWITCHES PARALLEL SWITCH ARCHITECTURE OUT-OF-SEQUENCE PERFORMANCE

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Interoperability test generation and minimization for communication protocols based on the multiple stimuli principle

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IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 2004年第10期22卷 2062-2074页

作者： Seol, S Kim, M Chanson, ST Kang, S Korea Telecom Telecommun Networks Lab Taejon 305811 South Korea Informat & Commun Univ Taejon 305714 South Korea Hong Kong Univ Sci & Technol Dept Comp Sci Kowloon Hong Kong Peoples R China

This paper presents an automatic test generation and minimization method for testing interoperability of communication protocols such as the asynchronous transfer mode/broadband integrated services digital network (ATM/B-ISDN) signaling protocol and the transmission control protocol (TCP). The method is based on a technique of composing finite-state machines (FSMs). Traditionally, the generation of inputs utilizing FSM was mostly based on sequential test scripting languages and often done manually. Each input is processed on a one-at-a-time basis, which did not allow generating complex scenarios of simultaneous inputs on several interfaces of the system under test (SUT). In practice, there exists the possibility that additional inputs have to be sent to the SUT, while the previous input is still being processed, and/or multiple inputs need to be sent to different interfaces of the SUT at the same time. Our method generates interoperability test cases dealing with these more complex situations. Moreover, it minimizes the number of increased test cases due to the multiple stimuli without jeopardizing transition coverage. Experimental results have shown that compared with the conventional methods, our test generation method generates more interoperability test cases resulting in higher transition coverage (26% higher for TCP and 12% higher for ATM signaling protocol). Also, our test minimization method reduces the interoperability test cases by about 94% in the case of the ATM signaling protocol with the same transition coverage.

关键词： conformance testing interoperability testing protocols test case generation test minimization validation

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Approximation error analysis for partially coherent EGC receiver under Nakagami-m fading channels

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IEICE TRANSACTIONS ON COMMUNICATIONS 2007年第5期E90B卷 1245-1248页

作者： Kim, Youngsun Kim, Kiseon KERI Power Telecommun Network Res Lab Uiwang City Gyeonggi Do South Korea Gwangju Inst Sci & Technol Commun & Sensor Networks Lab Kwangju South Korea

We present the approximated bit error rate (BER) performance of a binary phase shift keying (BPSK) modulated equal-gain combining (EGC) diversity receiver with phase noise over independent and non-identical Nakagami fading branches. The approximated BER becomes accurate with phase-locked loop (PLL) gain, K = 20. Also, for special values of fading parameter, m, and branch number, L, we derived the closed form expression of the BER.

关键词： equal-gain combining phase noise Nakagami fading channels

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Using an Event Data Taxonomy to Represent the Impact of Cyber Events as Geometrical Instances

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IEEE ACCESS 2018年 6卷 8810-8828页

作者： Gonzalez-Granadillo, Gustavo Rubio-Hernan, Jose Garcia-Alfaro, Joaquin ATOS Spain Atos Res & Innovat Cybersecur Lab Barcelona 08020 Spain Paris Saclay Univ Telecom SudParis Dept Networks & Telecommun Serv RST F-91011 Evry France

Visualization and simulation models used for the evaluation and selection of security countermeasures need accurate data to compute the impact of cyber events (e.g., malicious and benign actions). The information required to build appropriate impact models depends directly on the nature of the system. The information dealt by water supply systems, for instance, is particularly different from the information obtained by energy, telecommunication, transportation, or finance systems. It is, therefore, important to properly classify the data of security events according to the nature of the system. This paper proposes an event data taxonomy based on the system's criticality, the geographical location of the target, the time at which the information is obtained by the attacker, and the nature of the data. A use case on the impact assessment of events originated in a critical infrastructure is presented to show the applicability of the proposed taxonomy.

关键词： Security detection algorithms data visualization event detection security events event data taxonomies geometrical models impact assessment critical infrastructures

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TRANSLATION OF USERS QOS PARAMETERS INTO ATM PERFORMANCE REQUIREMENTS

TRANSLATION OF USERS QOS PARAMETERS INTO ATM PERFORMANCE REQ...

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IFIP TC6 2nd International Conference on Broadband Communications

作者： SERET, D JUNG, JI KOREA TELECOM TELECOMMUN NETWORK RES LABSOCHO KUSEOUL 137140SOUTH KOREA

ISBN: (纸本)0444818340

The paper deals with the Quality of Service concept in broadband ISDN. Its main goal is to present the translation of user's QoS parameters between layers. We concentrate on the translation from the AAL to the ATM layer because the AAL is designed to be service dependent and specific. The QoS parameters at the ATM layer resulting from the translation will be the performance requirements on a connection basis for the ATM network. Finally, we discuss the impact of QoS parameter translation on guaranteeing QoS in the ATM network.

关键词： QUALITY OF SERVICE BROAD-BAND COMMUNICATIONS NETWORK MANAGEMENT

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A new multi-level statistical model for variable bit rate MPEG sources over ATM networks and its performance study

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COMPUTER COMMUNICATIONS 2001年第3-4期24卷 296-307页

作者： Yoo, SJ Kim, SD Korea Telecom Telecommun Network Lab Network Planning Res Team Network Engn Div Taejon 305390 South Korea Korea Adv Inst Sci & Technol Dept Elect Engn Taejon 305701 South Korea

In this paper, we propose a new traffic model for MPEG-coded video sequences. The proposed modeling scheme uses scene-based traffic characteristics and considers the correlations between frames of consecutive group of pictures (GOPs). Using a simple scene detection algorithm, scene changes are modeled by a state transition matrix and the number of GOPs of a scene state is modeled by a geometric distribution. Frames of a scene are modeled by the mean I, P. and B frame sizes of each state. For more accurate traffic modeling, the residual bits that represent the difference between the original frame size and the mean frame size of each frame type are compensated by autoregressive processes. The modeling results show that our scene-based model can capture the statistical traffic characteristics of the original video sequences well and estimate the queueing performance with good approximation quality. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： traffic modeling MPEG scene-based model ATM networks variable bit rate

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An etch-stop technique using Cr₂O₃ thin film and its application to silica PLC platform fabrication

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ETRI JOURNAL 2002年第5期24卷 398-400页

作者： Shin, JU Kim, DJ Park, SH Han, YT Sung, HK Kim, J Park, SJ ETRI Basic Res Lab Taejon South Korea Korea Telecom Telecommun Networks Lab Taejon South Korea

Using Cr2O3 thin film, we developed a novel etch-stop technique for the protection of silicon surface morphology during deep ion coupled plasma etching of silica layers. With this technique we were able to etch a silica trench with a depth of over 20 pm without any damage to the exposed silicon terrace surface. This technique should be well applicable to fabricating silica planar lighwave circuit platforms for opto-electronic hybrid integration.

关键词： .waveguide exposed opto-electronic Fabricating Hybrid Integration Etch-Stop Cr Thin Film silica layers silicon terrace Silica PLC platforms ICP etching

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BER and power penalty fluctuations due to PMD statistics in 10 Gbit/s optical transmissions

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ELECTRONICS LETTERS 2002年第12期38卷 577-579页

作者： dos Santos, AB Jimenez, MR von der Weid, JP Djupsjöbacka, A Pontificia Univ Catolica Chile Ctr Telecommun Studies BR-22453900 Rio De Janeiro Brazil Ericsson Telecom AB Networks Res Lab S-12625 Stockholm Sweden

Polarisation-mode dispersion (PMD) in optical fibres causes a time-varying power penalty for the receiver, This variation has the same time-scale as low bit error rate (BER) measurements. Hereby, power penalty statistics can be difficult to determine with traditional BER measurements. A method where the statistics can be measured both quickly and accurately is proposed.

关键词： optical fibre dispersion PMD statistics optical fibres Optical communication equipment BER polarisation-mode dispersion receiver sensitivity curve time-varying power penalty error statistics 10 Gbit/s optical transmissions Fibre optics power penalty fluctuations low bit error rate measurements optical receivers 10 Gbit/s optical fibre polarisation

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Signaling cost and performance of SIGMA: A seamless handover scheme for data networks

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WIRELESS COMMUNICATIONS & MOBILE COMPUTING 2005年第7期5卷 825-845页

作者： Fu, SJ Atiquzzaman, M Ma, LR Lee, YI Univ Oklahoma Sch Comp Sci Telecommun & Networks Res Lab Norman OK 73019 USA Korea Natl Univ Educ Dept Technol Educ Chungbuk 363791 South Korea

Mobile IP has been developed to handle mobility of Internet hosts at the network layer. Mobile IP (MIP), however, suffers from a number of drawbacks such as requirement of infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions. In this paper, we describe and evaluate the performance of SIGMA, a Seamless IP diversity-based Generalized Mobility Architecture. SIGMA utilizes multihoming to achieve seamless handover of mobile hosts, and is designed to solve many of the drawbacks of MIP, including requirement for changes in infrastructure. We first evaluate the signaling cost of SIGMA and compare with that of hierarchical Mobile IPv6 (an enhancement of Mobile IP) by analytical modeling, followed by comparison of handover performance of SIGMA and Mobile IPv6 enhancements. Criteria for performance evaluation include handover latency, packet loss, throughput, and network friendliness. Our results indicate that in most cases SIGMA has a lower signaling cost than Hierarchical Mobile IPv6. Moreover, for a typical network configuration, SIGMA has a higher handover performance over Mobile IP Copyright (C) 2005 John Wiley & Sons, Ltd.

关键词： mobile handover SIGMA mobile IP IP diversity signaling cost

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