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2015年

作者： Alberto Paradisi Michel Daoud Yacoub Fabrcio Lira Figueiredo Tania Regina Tronco

ISBN: (纸本)9783319238227

This book focus on Long Term Evolution (LTE) and beyond. The chapters describe different aspects of research and development in LTE, LTE-Advanced (4G systems) and LTE-450 MHz such as telecommunications regulatory framework, voice over LTE, link adaptation, power control, interference mitigation mechanisms, performance evaluation for different types of antennas, cognitive mesh network, integration of LTE network and satellite, test environment, power amplifiers and so on. It is useful for researchers in the field of mobile communications.

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Experimental-based subsystem models for simulation of heterogeneous optical networks

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Journal of Microwaves, Optoelectronics and Electromagnetic Applications 2014年第2期13卷 87-103页

作者： Magalhães, Eduardo Garrich, Miquel Moura, Uiara Nascimento, Lara Oliveira, Juliano Bordonalli, Aldário Optical System Division CPqD - Telecom and IT Solutions Campinas Brazil DMO FEEC UNICAMP Campinas Brazil

This work presents and analyzes experimental-based subsystem models for Erbium doped fiber amplifiers (EDFAs) and wavelength selective switches (WSSs) under operation in a metropolitan optical network testbed. Firstly, the performance of the EDFAs and two gain control types are analyzed in a heterogeneous experimental setup with lightpaths modulated at 10G/100G/200G. Secondly, the WSS optical shape filter is experimentally characterized. Subsequently, simulation models are proposed accordingly to the experimental data obtained from the experimental setups. Results of output power and spectrum shape for both amplifiers under test showed good agreement between simulation and experiment. In addition, the optical signal-to-noise ratio (OSNR) for all channels was also analyzed and it was obtained error values bellow 1 dB, which are within an acceptable error margin. The developed sub-system models will provide greater flexibility to simulate different network scenarios and enable the development and validation of future optical network intelligence algorithms. © 2014 SBMO/SBMag.

关键词： Erbium doped fiber amplifiers

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Competitive neural networks for fault detection and diagnosis in 3G cellular systems

Competitive neural networks for fault detection and diagnosi...

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11th International Conference on telecommunications, ICT 2004

作者： Barreto, Guilherme A. Mota, João C. M. Souza, Luís G. M. Frota, Rewbenio A. Aguayo, Leonardo Yamamoto, José S. Macedo, Pedro E. O. Department of Teleinformatics Engineering Federal University of Ceará Fortaleza-CE Brazil CPqD Telecom and IT Solutions Campinas-SP Brazil

ISBN: (纸本)3540225714

We propose a new approach to fault detection and diagnosis in third-generation (3G) cellular networks using competitive neural algorithms. For density estimation purposes, a given neural model is trained with data vectors representing normal behavior of a CDMA2000 cellular system. After training, a normality profile is built from the sample distribution of the quantization errors of the training vectors. Then, we find empirical confidence intervals for testing hypotheses of normal/abnormal functioning of the cellular network. The trained network is also used to generate inference rules that identify the causes of the faults. We compare the performance of four neural algorithms and the results suggest that the proposed approaches outperform current methods. © Springer-Verlag Berlin Heidelberg 2004.

关键词： Fault detection

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Signal predistortion for nonlinear transmitters in direct-detection OFDM over multimode fibers

Signal predistortion for nonlinear transmitters in direct-de...

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International Symposium on telecommunications

作者： Celio K. H. Vasconcelos Andre N. Barreto Darli A. A. Mello Fábio D. Simões Department of Electrical Engineering University of Brasilia Brasilia Brazil Department of Communications (DECOM) University of Campinas Campinas Brazil CPqD Telecom & IT Solutions Campinas Brazil

This paper investigates the transmission of OFDM signals, generated by a directly-modulated VCSEL, over an optical channel estimated from experimental measurements in OM-3 multimode fibers. Simulation results indicate limitations on the system performance due to the nonlinear L-I curve of the VCSEL. We show that, in these conditions, the system performance can be improved by transmitter predistortion.

关键词： Optical transmitters Vertical cavity surface emitting lasers OFDM Predistortion Optical fibers Modulation

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Node architectures for next generation ROADMs: A comparative study among emergent optical solutions

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Journal of Microwaves, Optoelectronics and Electromagnetic Applications 2013年第SPEC. ISSUE 2期12卷 156-166页

作者： Magalhães, Eduardo C. Nascimento, Marcelo R. De Oliveira, Vinícius G. Angeli, Bruno C. C. De Oliveira, Juliano R. F. De Oliveira, Júlio C. R. F. Bordonalli, Aldário C. Optical System Division CPqD - Telecom and IT Solutions Campinas Brazil DMO FEEC UNICAMP Campinas Brazil

Reconfigurable optical add and drop multiplexers (ROADMs) are key components to increase the dynamicity and flexibility of optical networks. In its first generation, solely based on PLC and WSS-technology, ROADMs allowed service providers to automate some of its network operations, reducing the OPEX and improving the quality of service offered to the customer. However, the current solution is limited to several constrains such as direction, color and contention, and still demands truck rolls and manual reconfiguration depending on the desired operation. To address this limitation, new optical components are emerging and particularly two node architectures are being considered as most promising candidates: multicast switch with optical amplification array and dense low loss fiber optical cross-connect with MUX/DEMUX AWGs. This paper compares both solutions, and a third variation using fiber OXC in conjunction with WSS, from a CAPEX and OPEX perspective. It concludes that depending on the network scenario one solution is more suitable than the others and probably, in the next generation reality, different node architectures will be required in different portions of a same network. © 2013 SBMO/SBMag.

关键词： Multicasting

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The IJCB 2014 PaSC video face and person recognition competition 2

The IJCB 2014 PaSC video face and person recognition competi...

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2nd IEEE/IAPR International Joint Conference on Biometrics, IJCB 2014

作者： Beveridge, J. Ross Zhang, Hao Flynn, Patrick J. Lee, Yooyoung Liong, Venice Erin Lu, Jiwen De Assis Angeloni, Marcus De Freitas Pereira, Tiago Li, Haoxiang Hua, Gang Struc, Vitomir Krizaj, Janez Phillips, P. Jonathon Colorado State University Fort CollinsCO United States University of Notre Dame Notre DameIN United States NIST GaithersburgMD United States Advanced Digital Science Center Singapore Singapore CPqD Telecom and IT Solutions Campinas SP Brazil Stevens Institute of Technology HobokenNJ United States University of Ljubljana Ljubljana Slovenia

ISBN: (纸本)9781479935840

The Point-and-Shoot Face Recognition Challenge (PaSC) is a performance evaluation challenge including 1401 videos of 265 people acquired with handheld cameras and depicting people engaged in activities with non-frontal head pose. This report summarizes the results from a competition using this challenge problem. In the Video-to-video Experiment a person in a query video is recognized by comparing the query video to a set of target videos. Both target and query videos are drawn from the same pool of 1401 videos. In the Still-to-video Experiment the person in a query video is to be recognized by comparing the query video to a larger target set consisting of still images. Algorithm performance is characterized by verification rate at a false accept rate of 0.01 and associated receiver operating characteristic (ROC) curves. Participants were provided eye coordinates for video frames. Results were submitted by 4 institutions: (i) Advanced Digital Science Center, Singapore;(ii) cpqd, Brasil;(iii) Stevens Institute of Technology, USA;and (iv) University of Ljubljana, Slovenia. Most competitors demonstrated video face recognition performance superior to the baseline provided with PaSC. The results represent the best performance to date on the handheld video portion of the PaSC. © 2014 IEEE.

关键词： Face recognition

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LBP-TOP based countermeasure against face spoofing attacks

LBP-TOP based countermeasure against face spoofing attacks

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11th Asian Conference on Computer Vision, ACCV 2012

作者： De Freitas Pereira, Tiago Anjos, André De Martino, José Mario Marcel, Sébastien Brazil CPqD Telecom and IT Solutions Brazil IDIAP Research Institute Switzerland

ISBN: (纸本)9783642374098

User authentication is an important step to protect information and in this field face biometrics is advantageous. Face biometrics is natural, easy to use and less human-invasive. Unfortunately, recent work has revealed that face biometrics is vulnerable to spoofing attacks using low-tech cheap equipments. This article presents a countermeasure against such attacks based on the LBP-TOP operator combining both space and time information into a single multiresolution texture descriptor. Experiments carried out with the REPLAY ATTACK database show a Half Total Error Rate (HTER) improvement from 15.16% to 7.60%. © 2013 Springer-Verlag.

关键词： Authentication

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Can face anti-spoofing countermeasures work in a real world scenario?

Can face anti-spoofing countermeasures work in a real world ...

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6th IAPR International Conference on Biometrics, ICB 2013

作者： De Freitas Pereira, Tiago Anjos, Andre De Martino, Jose Mario Marcel, Sebastien Brazil CPqD Telecom and IT Solutions Brazil IDIAP Research Institute China

ISBN: (纸本)9781479903108

User authentication is an important step to protect information and in this field face biometrics is advantageous. Face biometrics is natural, easy to use and less human-invasive. Unfortunately, recent work has revealed that face biometrics is vulnerable to spoofing attacks using low-tech equipments. This article assesses how well existing face anti-spoofing countermeasures can work in a more realistic condition. Experiments carried out with two freely available video databases (Replay Attack Database and CASIA Face Anti-Spoofing Database) show low generalization and possible database bias in the evaluated countermeasures. To generalize and deal with the diversity of attacks in a real world scenario we introduce two strategies that show promising results. © 2013 IEEE.

关键词： Database systems

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The IJCB 2014 PaSC video face and person recognition competition

The IJCB 2014 PaSC video face and person recognition competi...

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IEEE International Joint Conference on Biometrics (IJCB)

作者： J. Ross Beveridge Hao Zhang Patrick J. Flynn Yooyoung Lee Venice Erin Liong Jiwen Lu Marcus de Assis Angeloni Tiago de Freitas Pereira Haoxiang Li Gang Hua Vitomir Štruc Janez Križaj P. Jonathon Phillips Colorado State University Fort Collins CO USA University of Notre Dame Notre Dame IN USA NIST Gaithersburg MD USA Advanced Digital Science Center Singapore CPqD Telecom & IT Solutions Campinas SP Brasil Stevens Institute of Technology Hoboken NJ USA University of Ljubljana Ljubljana Slovenia

The Point-and-Shoot Face Recognition Challenge (PaSC) is a performance evaluation challenge including 1401 videos of 265 people acquired with handheld cameras and depicting people engaged in activities with non-frontal head pose. This report summarizes the results from a competition using this challenge problem. In the Video-to-video Experiment a person in a query video is recognized by comparing the query video to a set of target videos. Both target and query videos are drawn from the same pool of 1401 videos. In the Still-to-video Experiment the person in a query video is to be recognized by comparing the query video to a larger target set consisting of still images. Algorithm performance is characterized by verification rate at a false accept rate of 0.01 and associated receiver operating characteristic (ROC) curves. Participants were provided eye coordinates for video frames. Results were submitted by 4 institutions: (i) Advanced Digital Science Center, Singapore; (ii) cpqd, Brasil; (iii) Stevens Institute of Technology, USA; and (iv) University of Ljubljana, Slovenia. Most competitors demonstrated video face recognition performance superior to the baseline provided with PaSC. The results represent the best performance to date on the handheld video portion of the PaSC.

关键词： Face Face recognition Educational institutions Feature extraction Cameras Vectors Histograms

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The 2nd competition on counter measures to 2D face spoofing attacks

The 2nd competition on counter measures to 2D face spoofing ...

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6th IAPR International Conference on Biometrics, ICB 2013

作者： Chingovska, I. Yang, J. Lei, Z. Yi, D. Li, S.Z. Kahm, O. Glaser, C. Darner, N. Kuijper, A. Nouak, A. Komulainen, J. Pereira, T. Gupta, S. Khandel Wa, S. Bansal, S. Rai, A. Krishna, T. Goyal, D. Waris, M.-A. Zhang, H. Ahmad, I. Kiranyaz, S. Gabbouj, M. Tronci, R. Pili, M. Sirena, N. Roli, F. Galbally, J. Ficrrcz, J. Pinto, A. Pedrini, H. Schwartz, W.S. Rocha, A. Anjos, A. Marcel, S. Idiap Research Institute Switzerland Chinese Academy of Sciences China Fraunhofer Institute for Computer Graphics Research IGD Germany University of Oulu Finland University of Campinas Brazil CPqD Telecom and IT Solutions Brazil LNM Institute of Information Technology India Tampere University of Technology Finland University of Cagliari Italy Universidad Autonoma de Madrid Spain Universidade Federal de Minas Gerais Brazil

ISBN: (纸本)9781479903108

As a crucial security problem, anti-spoofing in biomet-rics, and particularly for the face modality, has achieved great progress in the recent years. Still, new threats arrive in form of better, more realistic and more sophisticated spoofing attacks. The objective of the 2nd Competition on Counter Measures to 2D Face Spoofing Attacks is to challenge researchers to create counter measures effectively detecting a variety of attacks. The submitted propositions are evaluated on the Replay-Attack database and the achieved results are presented in this © 2013 IEEE.

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