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Publications

Abstract

SCADA (Supervisory Control and Data Acquisition) databases have three main features that identify them as big data systems: volume, variety and velocity. SCADAs are extremely important for the safety and security operation of modern power system and

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BibTeX

@article{alves2017hybrid,
title={A Hybrid approach for big data outlier detection from electric power SCADA system},
author={Alves, Wesin and Martins, Daniel and Bezerra, Ubiratan and Klautau, Aldebaro},
journal={IEEE Latin America Transactions},
volume={15},
number={1},
pages={57–64},
year={2017},
publisher={IEEE}
}

Abstract

Several new architectures are under investigation for cloud radio access networks, assuming distinct splits of functionality among the network elements. Consequently, the research on radio data compression for the fronthaul is based on assumptions that

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BibTeX

@article{ramalho2017lpc,
title={An LPC-Based Fronthaul Compression Scheme},
author={Ramalho, Leonardo and Fonseca, Maria Nilma and Klautau, Aldebaro and Lu, Chenguang and Berg, Miguel and Trojer, Elmar and H{\”o}st, Stefan},
journal={IEEE Communications Letters},
volume={21},
number={2},
pages={318–321},
year={2017},
publisher={IEEE}
}

Abstract

Alien crosstalk is one of the major impairments for copper-based transmissions. This letter outlines a method for mitigating alien crosstalk for DSL downstream transmissions impaired by multiple interference sources. The method requires a reference channel, and includes a

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BibTeX

@article{gomes2017mitigation,
title={Mitigation of Alien Crosstalk for Downstream DSL Impaired by Multiple Interferers},
author={Gomes, Diego and Medeiros, E and Klautau, Aldebaro and Pelaes, Evaldo},
journal={IEEE Communications Letters},
year={2017},
publisher={IEEE}
}

Abstract

Sophisticated communication technologies are developed using simulators, emulators and prototypes. In many situations emulators represent a good tradeoff in terms of flexibility and realism. OpenAirInterface (OAI) is an open-source emulation platform of 4G/5G

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BibTeX

@article{nahumemulation,
title={Emulation of 4G/5G Network Using OpenAirInterface},
author={Nahum, Cleverson and Soares, Jos{\’e} and Batista, Pedro and Klautau, Aldebaro}
}

Abstract

Systems and methods for determining non-linear precoding coefficients are disclosed. In some embodiments, a method of determining non-linear precoding coefficients for transmitting at least one frequency tone on lines includes obtaining a channel matrix that

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BibTeX

@misc{lu2017systems,
title={Systems and methods for determining non-linear precoding coefficients},
author={Lu, Chenguang and Eriksson, Per-Erik and Klautau, Aldebaro and M{\”u}ller, Francisco and Zu, Keke},
year={2017},
month=oct # “~24”,
publisher={Google Patents},
note={US Patent 9,800,720}
}

Abstract

The recent growth of Internet traffic and the forecast of new applications on context of fifth generation of network technology (5G) leads to changes in the communication paradigm of future Internet. The Information Centric Networking (ICN) is a new architecture

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BibTeX

@article{ramosforwarding,
title={Forwarding Strategies in ICN networking with a 5G Application},
author={Ramos, Ivanildo and Ara{\’u}jo, Ivanes and Klautau, Aldebaro}
}

Abstract

This paper presents an architecture and an implementation of a field-programmable gate array (FPGA)-based Ethernet fronthaul testbed. The system exploits the IEEE 1588 precision time protocol for clock synchronization and is capable of transporting radio data from one

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BibTeX

@inproceedings{freire2017fpga,
title={An FPGA-based Design of a Packetized Fronthaul Testbed with IEEE 1588 Clock Synchronization},
author={Freire, Igor and Lu, Chenguang and Berg, Miguel and Klautau, Aldebaro},
booktitle={European Wireless 2017; 23th European Wireless Conference; Proceedings of},
pages={1–6},
year={2017},
organization={VDE}
}

Abstract

Cloud radio access network (C-RAN) is a recent trend of RAN architecture positioned to help the operators to address challenges of new wireless services, such as emerging 4G and 5G mobile networks. C-RAN uses baseband processing units in a central

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BibTeX

@inproceedings{paulo2016fpga,
title={FPGA-based testbed for synchronization on Ethernet fronthaul with phase noise measurements},
author={Paulo, Joary and Freire, Igor and Sousa, Ilan and Lu, Chenguang and Berg, Miguel and Almeida, Igor and Klautau, Aldebaro},
booktitle={Instrumentation Systems, Circuits and Transducers (INSCIT), International Symposium on},
pages={132–136},
year={2016},
organization={IEEE}
}

Abstract

Due to the much higher crosstalk impairing in G. fast high-frequency channels compared with digital subscriber line low-frequency channels, the nonlinear Tomlinson-Harashima precoding (THP) has a good potential to enhance the G. fast system

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BibTeX

@article{zu2016rate,
title={Rate Balancing Based Tomlinson–Harashima Precoding for G. Fast Systems},
author={Zu, Keke and M{\”u}ller, Francisco CBF and Lu, Chenguang and Eriksson, Per-Erik and Klautau, Aldebaro},
journal={IEEE Communications Letters},
volume={20},
number={8},
pages={1519–1522},
year={2016},
publisher={IEEE}
}

Abstract

Grounding systems play an important role in electrical substations. They prevent grounding potential rise (GPR) during current fault events. GPR can cause the known step or touch voltages that can hurt people around the substations. Over time, grounding systems

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BibTeX

@inproceedings{ramalho2016data,
title={Data acquisition system for continuous monitoring of grounding grids in energized substations},
author={Ramalho, Leonardo and Rocha, Willian and Nakamura, Andrey and Arajo, Bruno and Castro, Adalbery and Klautau, Aldebaro and Lima, Ribamar and Freire, Raimundo},
booktitle={Instrumentation Systems, Circuits and Transducers (INSCIT), International Symposium on},
pages={113–117},
year={2016},
organization={IEEE}
}

Abstract

Provisioning of cost-effective Ethernet-based fronthaul by reusing the LAN infrastructure available in most commercial buildings is challenging predominantly in terms of the required bandwidth and synchronization. In contrast to a synchronous fronthaul, a PTP-

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BibTeX

@inproceedings{freire2016analysis,
title={Analysis and Evaluation of End-to-End PTP Synchronization for Ethernet-Based Fronthaul},
author={Freire, Igor and Sousa, Ilan and Klautau, Aldebaro and Almeida, Igor and Lu, Chenguang and Berg, Miguel},
booktitle={Global Communications Conference (GLOBECOM), 2016 IEEE},
pages={1–6},
year={2016},
organization={IEEE}
}

Abstract

A classificação automática de modulação (CAM) é um importante processo nos sistemas militares e de rádio cognitivo, a qual consiste em identificar a modulação adotada sem haver cooperação do transmissor. No entanto a avaliação desses sistemas é

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BibTeX

@article{silvabase,
title={Base de Dados para Avalia{\c{c}}{\~a}o de Algoritmos de Classifica{\c{c}}{\~a}o de Modula{\c{c}}{\~a}o},
author={Silva, Andrey and Paulo, Joary and Klautau, Aldebaro}
}

Abstract

Summary This work describes and proposes the application of evolutionary algorithms on the multiuser spectrum and SNR margin optimization problem for multicarrier systems, such as digital subscriber line. The proposed method is designed such that it takes advantage of

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BibTeX

@article{gomes2016hybrid,
title={An hybrid evolutionary multiobjective algorithm for multiuser margin maximization in DSL},
author={Gomes, Ana and Monteiro, Marcio and Dortschy, Boris and Klautau, Aldebaro},
journal={International Journal of Communication Systems},
volume={29},
number={1},
pages={194–209},
year={2016},
publisher={Wiley Online Library}
}

Abstract

Summary This work proposes a new method for automatically identifying topologies of lines with one or more sections in a telephone network. The method is based on the examination of both impulse response and time-domain reflectometry trace of a line under test. They are

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BibTeX

@article{lima2016wavelet,
title={A wavelet-based expert system for digital subscriber line topology identification},
author={Lima, VD and Klautau, Aldebaro and Costa, Jo{\~a}o and Ericson, Klas and Fertner, Antoni and Sales, Claudomiro},
journal={International Journal of Communication Systems},
volume={29},
number={1},
pages={47–63},
year={2016},
publisher={Wiley Online Library}
}

Abstract

Voice imitation basically consists in estimating a synthesizers input parameters to mimic a target speech signal. This is a difficult inverse problem because the mapping is time-varying

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BibTeX

@article{araujo2016genetic,
title={Genetic algorithm to estimate the input parameters of Klatt and HLSyn formant-based speech synthesizers},
author={Ara{\’u}jo, Fab{\’\i}ola and Klautau, Aldebaro and others},
journal={Biosystems},
volume={150},
pages={190–193},
year={2016},
publisher={Elsevier}
}

Abstract

G. fast is a new standard for fixed broadband access that aims at achieving bit rates of 1 Gb/s over short copper loops. In order to give support to simulation, design and performance evaluation tests, the G. fast recommendation presents examples of some wiring

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BibTeX

@inproceedings{acatauassu2015khm,
title={KHM cable model parameters for ITU-T G. fast reference loops},
author={Acatauassu, Diogo and H{\”o}st, Stefan and Lu, Chenguang and Berg, Miguel and Costa, Jo{\~a}o and Klautau, Aldebaro and {\”O}dling, Per and B{\”o}rjersson, Per Ola},
booktitle={Standards for Communications and Networking (CSCN), 2015 IEEE Conference on},
pages={168–173},
year={2015},
organization={IEEE}
}

Abstract

G. fast is the most recent ITU-T standard for copper-based transmission, which targets at short distances and adopts a bandwidth of 106 MHz extensible to 212 MHz. In several scenarios G. fast systems will be composed by or coexist with uncoordinated lines,

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BibTeX

@inproceedings{de2015feasibility,
title={Feasibility of alien crosstalk mitigation with receiver-side MIMO processing on G. fast systems},
author={de Azevedo Gomes, Diego and Freire, Igor and Klautau, Aldebaro and Pelaes, Evaldo},
booktitle={Telecommunications (IWT), 2015 International Workshop on},
pages={1–7},
year={2015},
organization={IEEE}
}

Abstract

The requirement of higher data rates motivates the adoption of high-order modulations and pulse shaping in optical systems. This paper proposes an efficient architecture for FPGA-based parallel fractional sample rate conversion that has an optimum

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BibTeX

@inproceedings{sousa2015parallel,
title={Parallel polyphase filtering for pulse shaping on high-speed optical communication systems},
author={Sousa, Ilan and Boas, Brenda Vilas and Freire, Igor and Klautau, Aldebaro and Reis, Jacklyn D},
booktitle={Microwave and Optoelectronics Conference (IMOC), 2015 SBMO/IEEE MTT-S International},
pages={1–5},
year={2015},
organization={IEEE}
}

Abstract

Traffic forecasts suggest increasing mobile data rates, which motivates research on new technologies collectively called 5G features. Among these is hyper-dense deployment of small cells to maximize capacity. However, this small cell deployment can significantly

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BibTeX

@inproceedings{araujo2015traffic,
title={Traffic-aware sleep mode algorithm for 5G networks},
author={Araujo, Ivanes Lian Costa and Klautau, Aldebaro},
booktitle={Telecommunications (IWT), 2015 International Workshop on},
pages={1–5},
year={2015},
organization={IEEE}
}

Abstract

We compare schemes from two different standards for copper twisted pairs in light of the upcoming G. fast standard for Digital Subscriber Lines. Various configurations are compared based on error performance. This contribution confirms quantitatively that Low-

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BibTeX

@inproceedings{takeda2015comparison,
title={A comparison between RS+ TCM and LDPC for G. fast channel coding},
author={Takeda, Marcos and Smith, Fernanda and Klautau, Aldebaro},
booktitle={Circuits \& Systems (LASCAS), 2015 IEEE 6th Latin American Symposium on},
pages={1–5},
year={2015},
organization={IEEE}
}

Abstract

A method and arrangement is proposed for adaptively generating a target noise margin for use on a DSL transmission line. The method includes determining a first quantity representing a current noise power on the line using line parameter data relating to the

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BibTeX

@misc{de2015dynamic,
title={Dynamic target margin adaptation for DSL transmission lines},
author={de Medeiros, Eduardo Lins and Dortschy, Boris and Klautau, Aldebaro and Monteiro, Marcio Murilo Conte},
year={2015},
month=mar # “~17”,
publisher={Google Patents},
note={US Patent 8,983,060}
}

Abstract

Background Utterance copy consists in estimating the input parameters to reconstruct a speech signal using a speech synthesizer. This process is distinct from the more traditional text-to-speech but yet used in many areas, especially in linguistics and

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BibTeX

@article{klautau2015utterance,
title={Utterance copy through analysis-by-synthesis using genetic algorithm},
author={Klautau, Aldebaro and Ara{\’u}jo, Fab{\’\i}ola and others},
journal={Journal of the Brazilian Computer Society},
volume={21},
number={1},
pages={17},
year={2015}
}

Abstract

Techniques for Structural Health Monitoring (SHM) have been the subject of intense research recently. This trend can be attributed to the high costs of maintenance and repair of large infrastructures, besides the loss of invaluable lives in catastrophic accidents,

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BibTeX

@article{nunes2015sistema,
title={Sistema de Monitoramento de Integridade Estrutural Baseado em Rede de Sensores},
author={Nunes, Fl{\’a}vio and Corr{\^e}a, Lucas and Castro, Adalbery and Klautau, Aldebaro},
journal={Anais do Computer on the Beach},
pages={446–448},
year={2015}
}

Abstract

A method is proposed for compiling a corpus of phonetically-rich triphone sentences; ie, sentences with a high variety of triphones, distributed in a uniform fashion. Such a corpus is of interest for a wide range of contexts, from automatic speech recognition

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BibTeX

@inproceedings{mendoncca2014method,
title={A method for the extraction of phonetically-rich triphone sentences},
author={Mendon{\c{c}}a, Gustavo and Candeias, Sara and Perdig{\~a}o, Fernando and Shulby, Christopher and Toniazzo, Rean and Klautau, Aldebaro and Alu{\’\i}sio, Sandra},
booktitle={Telecommunications Symposium (ITS), 2014 International},
pages={1–5},
year={2014},
organization={IEEE}
}

Abstract

G. fast is a new standard from the International Telecommunication Union, which targets 1 Gb/s over short copper loops using frequencies up to 212 MHz. This new technology requires accurate parametric cable models for simulation, design, and

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BibTeX

@article{acatauassu2014simple,
title={Simple and causal copper cable model suitable for G. fast frequencies},
author={Acatauassu, Diogo and H{\”o}st, Stefan and Lu, Chenguang and Berg, Miguel and Klautau, Aldebaro and B{\”o}rjesson, Per Ola},
journal={IEEE Transactions on Communications},
volume={62},
number={11},
pages={4040–4051},
year={2014},
publisher={IEEE}
}

Abstract

The cyclic prefix adopted by discrete multitone (DMT) systems may impose a data rate reduction or be insufficient to prevent inter-symbol and inter-carrier interference from distorting the received symbols and degrading the system performance. Thus, techniques

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BibTeX

@inproceedings{freire2014low,
title={Low complexity precoder and equalizer for dmt systems with insufficient cyclic prefix},
author={Freire, Igor and Lu, Chenguang and Eriksson, Per-Erik and Klautau, Aldebaro},
booktitle={Global Communications Conference (GLOBECOM), 2014 IEEE},
pages={3243–3248},
year={2014},
organization={IEEE}
}

Abstract

The use of vectoring for crosstalk cancellation in the new ITU-T G. fast standard for next generation DSL systems becomes essential for efficient utilization of the extended bandwidth (up to 200 MHz). In VDSL2 (up to 30 MHz), a zero-forcing-based linear precoder

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BibTeX

@inproceedings{muller2014optimizing,
title={Optimizing power normalization for G. fast linear precoder by linear programming},
author={Muller, Francisco CBF and Lu, Chenguang and Eriksson, Per-Erik and Host, Stefan and Klautau, Aldebaro},
booktitle={Communications (ICC), 2014 IEEE International Conference on},
pages={4160–4165},
year={2014},
organization={IEEE}
}

Abstract

This work describes the current version of newGASpeech, a framework centered on analysis-by-synthesis and genetic algorithms for automatically estimating the input parameters of Klatts speech synthesizer. The goal is to speed up the process of speech”

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BibTeX

@inproceedings{sousa2014utterance,
title={Utterance copy for Klatt’s speech synthesizer using genetic algorithm},
author={Sousa, Jos{\’e} and Ara{\’u}jo, Fab{\’\i}ola and Klautau, Aldebaro},
booktitle={Spoken Language Technology Workshop (SLT), 2014 IEEE},
pages={89–94},
year={2014},
organization={IEEE}
}

Abstract

A method of determining a number of operating points for spectrum management of a plurality of digital subscriber lines in a communications network, the method comprising the steps of: determining optimization criteria (Oi) for the digital subscriber lines; determining

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BibTeX

@misc{dortschy2014operating,
title={Operating points for spectrum management in digital subscriber lines},
author={Dortschy, Boris and Bezerra, Johelden Campos and Klautau, Aldebaro and de Medeiros, Eduardo Lins and Monteiro, Marcio Murilo Conte},
year={2014},
month=may # “~13”,
publisher={Google Patents},
note={US Patent 8,724,799}
}

Abstract

Page 1. Universidade de São Paulo 2014-01 Listener: a pronunciation training system forBrazilian-accented English International Workshop on Cross-Language Speech Perception,2014, Braga. http://www.producao.usp.br/handle/BDPI/45554 Downloaded from: Biblioteca Digital

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BibTeX

@inproceedings{mendoncca2014listener,
title={Listener: a pronunciation training system for Brazilian-accented English},
author={Mendon{\c{c}}a, Gustavo Augusto and Candeias, Sara and Klautau, Aldebaro and Aluisio, Sandra Maria and others},
booktitle={International Workshop on Cross-Language Speech Perception},
year={2014},
organization={University of Minho}
}

Abstract

The present invention relates to a method and an arrangement based on two-port network (TPN) theory that allows analytically estimating the loop transfer function from open and short-circuited input impedance measurements, eg single ended line transmission (SELT)

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BibTeX

@misc{ericson2014method,
title={Method and arrangement for a digital subscriber line},
author={Ericson, Klas and Rodrigues, Roberto Menezes and Costa, Jo{\”a}o C Weyl Albuqerque and Klautau, Aldebaro},
year={2014},
month=aug # “~5”,
publisher={Google Patents},
note={US Patent 8,798,946}
}

Abstract

The present invention relates to a method for managing transmission resources in a digital communication system comprising an access network, such as a DSL system, implementing resource management for minimization of cross-talk interference in a cable or cable binder

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BibTeX

@misc{lindqvist2014method,
title={Method and a system for management of transmission resources in digital communication systems},
author={Lindqvist, Fredrik and Dortschy, Boris and Klautau, Aldebaro and da silva fonseca Lindqvist, Maria Neiva and Pelaes, Evaldo Goncalves},
year={2014},
month=sep # “~30”,
publisher={Google Patents},
note={US Patent 8,848,555}
}

Abstract

In this paper we investigate the use of the Support Vector Machine (SVM) approach to develop simple and efficient VLSI architectures for real-time digital modulation classification. Such simplicity and efficiency arise from the adoption of a front end block that

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BibTeX

@inproceedings{sorato2013real,
title={Real-time digital modulation classification based on Support Vector Machines},
author={Sorato, Edson and Fronza, Eduardo P and Barbosa, Paulo RFMM and G{\”u}ntzel, Jos{\’e} Lu{\’\i}s and Castro, Adalbery R and Klautau, Aldebaro},
booktitle={Integrated Circuits and Systems Design (SBCCI), 2013 26th Symposium on},
pages={1–6},
year={2013},
organization={IEEE}
}

Abstract

Several modern communication systems, such as G. fast-based copper transmission or LTE-based wireless systems, benefit from MIMO techniques to achieve higher capacity. In most of these techniques, the inversion of channel matrices is required.

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BibTeX

@inproceedings{fonseca2013high,
title={High speed GSGR matrix inversion algorithm with application to G. fast systems},
author={Fonseca, Ma Nilma and Klautau, Aldebaro},
booktitle={Microwave \& Optoelectronics Conference (IMOC), 2013 SBMO/IEEE MTT-S International},
pages={1–5},
year={2013},
organization={IEEE}
}

Abstract

The evolving broadband access systems using copper networks are currently deployed in a frequency band that goes up to 30 MHz, as specified in VDSL2. As hybrid fiber-copper architectures become more important in the industry and academia, using shorter

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BibTeX

@inproceedings{almeida2013capacity,
title={Capacity analysis of G. fast systems via time-domain simulations},
author={Almeida, Igor and Klautau, Aldebaro and Lu, Chenguang},
booktitle={Communications (ICC), 2013 IEEE International Conference on},
pages={4008–4013},
year={2013},
organization={IEEE}
}

Abstract

The GNU Radio and USRP are important tools that can be used by students to learn the theory of various areas, such as digital signal processing and telecommunications. This work presents how the GNU Radio and USRP has been used to transmit/receive

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BibTeX

@article{ramalhognu,
title={GNU Radio and USRP for Problem-Based Learning in Communications: Case Studies in Cellular Phone Jamming and Modulation Classification},
author={Ramalho, Leonardo and Fortuna, Joary and Santos, Lailson and Oliveira, Joeldo and Klautau, Aldebaro}
}

Abstract

The increasing demand for capacity has been driving the wireless communication standards to provide support to the coexistence of macro and small cells. The backhaul, which is the link between the radio access network and the backbone, is of increasing

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BibTeX

@inproceedings{lins2013requirements,
title={Requirements and evaluation of copper-based mobile backhaul for small cells LTE networks},
author={Lins, Silvia and Figueiredo, Pedro and Klautau, Aldebaro},
booktitle={Microwave \& Optoelectronics Conference (IMOC), 2013 SBMO/IEEE MTT-S International},
pages={1–5},
year={2013},
organization={IEEE}
}

Abstract

The use of a hybrid copper and fiber architecture is attractive in both fixed access and mobile backhauling scenarios. This trend led the industry and academia to start developing the fourth generation broadband system, which aims at achieving bit-rates of 1

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BibTeX

@inproceedings{acatauassu2013simple,
title={Simple and causal twisted-pair channel models for G. fast systems},
author={Acatauassu, Diogo and Höst, Stefan and Lu, Chenguang and Berg, Miguel and Klautau, Aldebaro and Borjesson, Per Ola},
booktitle={Global Communications Conference (GLOBECOM), 2013 IEEE},
pages={2834–2839},
year={2013},
organization={IEEE}
}

Abstract

There are several commercial text-to-speech (TTS) systems that generate speech signals that sound very natural. A distinct problem is utterance copy, which consists in taking speech as input (instead of text, as in TTS) and find the input parameters that would drive a

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BibTeX

@inproceedings{trindade2013genetic,
title={A genetic algorithm with look-ahead mechanism to estimate formant synthesizer input parameters},
author={Trindade, Jonathas and Ara{\’u}jo, Fab{\’\i}ola and Klautau, Aldebaro and Batista, Pedro},
booktitle={Evolutionary Computation (CEC), 2013 IEEE Congress on},
pages={3035–3042},
year={2013},
organization={IEEE}
}

Abstract

This letter presents a new algorithm for automatic modulation classification (AMC) and its implementation and validation as an intellectual property (IP) core. AMC aims at accurately identifying the modulation scheme of a given communication system in a short

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BibTeX

@article{cardoso2013efficient,
title={An efficient FPGA IP core for automatic modulation classification},
author={Cardoso, Claudomir and Castro, Adalbery R and Klautau, Aldebaro},
journal={IEEE Embedded Systems Letters},
volume={5},
number={3},
pages={42–45},
year={2013},
publisher={IEEE}
}

Abstract

This paper presents VLSI architectures to perform Digital Modulation Classification based on Support Vector Machines. In order to obtain suitably small circuitry, the designed architectures use a recently proposed front end that is based on histograms. Four versions of

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BibTeX

@inproceedings{sorato2013vlsi,
title={VLSI architectures for Digital Modulation Classification using Support Vector Machines},
author={Sorato, Edson and Netto, Renan and Michel, Pedro and G{\”u}ntzel, Jos{\’e} Lu{\’\i}s and Castro, Adalbery R and Klautau, Aldebaro},
booktitle={Circuits and Systems (LASCAS), 2013 IEEE Fourth Latin American Symposium on},
pages={1–4},
year={2013},
organization={IEEE}
}

Abstract

This paper promotes the need of choosing some and integrating the large variety of Free and Open Source Softwares (FOSS) to provide an integrated solution for information technology management and process improvement. The main motivation is that

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BibTeX

@article{haick2013free,
title={Free software tools for IT management and processes organisation: Case study in scientific research environment},
author={Haick, Bruno and Klautau, Aldebaro},
journal={Proceedings of WMSCI},
year={2013}
}

Abstract

ste trabalho apresenta um projeto de telefonia celular comunitária de
baixo custo, o CELCOM, e tem como objetivo oferecer, além de uma opção barata de telefonia móvel, uma alternativa de acesso à Internet através da tecnologia GPRS, podendo assim ser utilizada em aplicações de EaD (Educação à Distância) em comunidades isoladas das áreas rurais. Como será abordado ao longo do trabalho, existem diversos programas de inclusão digital que pretendem fornecer acesso à Internet banda larga para municípios das áreas rurais, no entanto, tais programas tem como alvo apenas as sedes desses municípios, negligenciando as comunidades mais afastadas que deles fazem parte, o trabalho aqui apresentando visa atender justamente essas comunidades isoladas, fornecendo não só uma alternativa para levar educação como também integrando-as ao resto do mundo.

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BibTeX

@article{leiteprojeto,
title={Projeto CELCOM: Uma alternativa tecnol{\’o}gica de baixo custo para desenvolvimento de EaD em comunidades rurais isoladas},
author={Leite, Jeferson and Cabral, Marcel and Nunes, Edgleyson and M{\”u}ller, Francisco and Klautau, Aldebaro}
}

Abstract

Dual-ended line testing (DELT) is a common capability in most current modems and can be used for digital subscriber line (DSL) qualification and monitoring purposes. In spite of that, this feature remains largely unexplored in the literature. This paper proposes a

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BibTeX

@inproceedings{sales2012expert,
title={Expert system based on wavelets and DELT measurements for VDSL systems},
author={Sales, Claudomiro and Lima, Vinicius and Ikeda, Gustavo and Rodrigues, Roberto M and Ericson, Klas and Klautau, Aldebaro and Costa, Jo{\~a}o},
booktitle={Global Communications Conference (GLOBECOM), 2012 IEEE},
pages={3110–3115},
year={2012},
organization={IEEE}
}

Abstract

Speech Synthesis is a mature field, with great results, and many differents techniques. One of most recent techniques is the HMM-based (Hidden Markov Models-based) approach, which is very interesting by its good results when using limited voice

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BibTeX

@inproceedings{costa2012sintetizador,
title={Um Sintetizador de Voz Baseado em HMMs Livre: Dando Novas Vozes para Aplica{\c{c}} oes Livres no Portugu{\^e}s do Brasil},
author={Costa, Ericson Sarmento and de Oliveira Monte, Anderson and Neto, Nelson and Klautau, Aldebaro},
booktitle={Workshop de Software Livre},
year={2012}
}

Abstract

The ability of a specific telephone line to support a certain digital subscriber line (DSL) service is determined by its downstream and upstream data rates, which are mainly dependent on the lines transfer function. In this way

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BibTeX

@article{rodrigues2012transfer,
title={Transfer function estimation of telephone lines from input impedance measurements},
author={Rodrigues, Roberto M and Sales, Claudomiro and Klautau, Aldebaro and Ericson, Klas and Costa, Jo{\~a}o},
journal={IEEE Transactions on Instrumentation and Measurement},
volume={61},
number={1},
pages={43–54},
year={2012},
publisher={IEEE}
}

Abstract

This paper presents the current stage of development of a fast Fourier transform (FFT) processor in VHDL. This processor uses fixed-point as numeric representation, taking advantage of the facilities provided by the IEEE fixed point package. Its main advantages is

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BibTeX

@article{correa2012vhdl,
title={Vhdl implementation of a flexible and synthesizable fft processor},
author={Correa, Ilan Sousa and Freitas, Lilian Coelho and Klautau, Aldebaro and Costa, Joao Crisostomo Weyl Albuquerque},
journal={IEEE Latin America Transactions},
volume={10},
number={1},
pages={1180–1183},
year={2012},
publisher={IEEE}
}

Abstract

A method and transmitter unit in a multi-tone multi-line based transmission system such as a digital subscriber line system for determining a Power Spectral Density (PSD) of a plurality of users over a physical channel for at least one tone. Each of the users has a minimum

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BibTeX

@misc{dortschy2012method,
title={Method and arrangement for power minimization in a multi-tone transmission-based communication system},
author={Dortschy, Boris and i Riu, Jaume Rius and Bastos, Moraes Rodrigo and Klautau, Aldebaro and Zampolo, Ronaldo},
year={2012},
month=aug # “~7”,
publisher={Google Patents},
note={US Patent 8,238,545}
}

Abstract

A method, central unit, and modem for reducing crosstalk in a Digital Subscriber Line (DSL) system. A virtual line referred to as a ghost line is introduced in the system as a substitution for all of the lines except a first line to induce crosstalk to the first line. The Power Spectral

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BibTeX

@misc{dortschy2012method,
title={Method central unit, and modem in a digital subscriber line network},
author={Dortschy, Boris and i Riu, Jaume Rius and Moraes, Rodrigo Bastos and Klautau, Aldebaro and Zampolo, Ronaldo},
year={2012},
month=oct # “~23”,
publisher={Google Patents},
note={US Patent 8,295,151}
}

Abstract

Advances in speech processing research rely on the availability of public resources such as corpora, statistical models and baseline systems. In contrast to languages such as English, there are few specific resources for Brazilian Portuguese. This work

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BibTeX

@article{oliveira2012baseline,
title={Baseline acoustic models for brazilian portuguese using CMU sphinx tools},
author={Oliveira, Rafael and Batista, Pedro and Neto, Nelson and Klautau, Aldebaro},
journal={Computational Processing of the Portuguese Language},
pages={375–380},
year={2012},
publisher={Springer}
}

Abstract

Cognitive radio (CR) is a novel technology that allows to improve spectrum utilization by enabling opportunistic access to the licensed spectrum band by unlicensed users 2. This is accomplished through heterogeneous architectures and techniques of dynamic spectrum

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BibTeX

@incollection{freitas2012data,
title={Data mining applied to cognitive radio systems},
author={Freitas, Lilian and Pires, Yomara and Morais, Jefferson and Costa, Jo{\~a}o and Klautau, Aldebaro},
booktitle={Advances in Data Mining Knowledge Discovery and Applications},
year={2012},
publisher={InTech}
}

Abstract

Digital subscriber lines (DSL), the broadband data transmission technologies that use the copper cable as channel, are the most used Internet media around the world with more than 300 million users (Oksman et al., 2010), Much of the DSL success is related to the cost-

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BibTeX

@incollection{acatauassu2012measurement,
title={Measurement and modeling techniques for the fourth generation broadband over copper},
author={Acatauassu, Diogo and Almeida, Igor and Muller, Francisco and Klautau, Aldebaro and Lu, Chenguang and Ericson, Klas and Dortschy, Boris},
booktitle={Advanced Topics in Measurements},
year={2012},
publisher={InTech}
}

Abstract

In recent years, the performance of personal computers has evolved with the production of ever faster processors, a fact that enables the adoption of speech processing in computer-assisted education. There are several speech technologies that are effective in education,

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BibTeX

@incollection{neto2012voiceconet,
title={VOICECONET: A Collaborative Framework for Speech-Based Computer Accessibility with a Case Study for Brazilian Portuguese},
author={Neto, Nelson and Batista, Pedro and Klautau, Aldebaro},
booktitle={Modern Speech Recognition Approaches with Case Studies},
year={2012},
publisher={InTech}
}

Abstract

The automatic modulation classification (AMC) problem aims at identifying the modulation scheme of a given communication system with a high probability of success and in a short period of time. AMC has been used for decades in military applications in which friendly

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BibTeX

@incollection{castro2012modulation,
title={Modulation Classification in Cognitive Radio},
author={Castro, Adalbery R and Freitas, Lilian C and Cardoso, Claudomir C and Costa, Jo{\~a}o CWA and Klautau, Aldebaro BR},
booktitle={Foundation of Cognitive Radio Systems},
year={2012},
publisher={InTech}
}

Abstract

The Klatt synthesizer is considered one of the most important formant synthesis. Therefore, this chapter addresses the problem of automatic estimation of Klatts synthesizer parameters in order to perform the imitation of voice (utterance copy)

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BibTeX

@incollection{araujo2012multi,
title={Multi-Objective Genetic Algorithm to Automatically Estimating the Input Parameters of Formant-Based Speech Synthesizers},
author={Ara{\’u}jo, Fab{\’\i}ola and Trindade, Jonathas and Borges, Jos{\’e} and Klautau, Aldebaro and Couto, Igor},
booktitle={Real-World Applications of Genetic Algorithms},
year={2012},
publisher={InTech}
}

Abstract

Recently, the industry and the academy started to discuss the development of the fourth generation DSL systems. For example, within this context, ITU started working in G. fast DSL standard. A trend in this new generation is to increase the end-user bit rates by

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BibTeX

@inproceedings{acatauassu2011experimental,
title={Experimental evaluation of fourth generation DSL in different DSM scenarios},
author={Acatauassu, Diogo and Monteiro, Marcio and Muller, Francisco and Klautau, Aldebaro},
booktitle={Communications (LATINCOM), 2011 IEEE Latin-American Conference on},
pages={1–6},
year={2011},
organization={IEEE}
}

Abstract

This paper presents some improvements on an existing set of linguistic rules that is capable of performing the syllabification of Brazilian Portuguese words. An algorithm was also implemented and based on this set, which improvements previously mentioned

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BibTeX

@inproceedings{monte2011rule,
title={A rule-based syllabification algorithm with stress determination for Brazilian Portuguese natural language processing},
author={Monte, Anderson and Ribeiro, Danielle and Neto, Nelson and Cruz, Regina and Klautau, Aldebaro},
booktitle={17th international congress of phonetic sciences},
pages={1418–1421},
year={2011}
}

Abstract

This work presents a novel method for automatic modulation classification based on discriminative learning. The features are the ordered magnitude and phase of the received symbols at the output of the matched filter. The results using the proposed front end

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BibTeX

@article{muller2011front,
title={A front end for discriminative learning in automatic modulation classification},
author={Muller, Francisco CBF and Cardoso Jr, Claudomir and Klautau, Aldebaro},
journal={IEEE Communications Letters},
volume={15},
number={4},
pages={443–445},
year={2011},
publisher={IEEE}
}

Abstract

This work presents ListenU, a tool for environmental monitoring using wireless sensor networks that allows collecting physical information. Based on the TinyOS operating system and presented with MicaZ sensors, a base station and an easy graphical interface,

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BibTeX

@misc{sousa2011listenu,
title={ListenU uma Ferramenta para Monitoramento Ambiental Usando Redes de Sensores Sem Fio},
author={Sousa, Ilan and Am{\’e}rico, Lauro and Freitas, Lilian and Klautau, Aldebaro and Costa, Jo{\~a}o},
year={2011}
}

Abstract

This work presents the simulation and analysis of the impact of impulsive noise on video transmission over ADSL using the Ptolemy II framework. The implemented software modem includes channel coding and modulation used in the ADSL standard and an

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BibTeX

@inproceedings{smith2011simulation,
title={Simulation and analysis of the impulsive noise effects in DSL video using Ptolemy II},
author={Smith, Fernanda and M{\”u}ller, Francisco and Klautau, Aldebaro and Pelaes, Evaldo},
booktitle={Microwave \& Optoelectronics Conference (IMOC), 2011 SBMO/IEEE MTT-S International},
pages={157–161},
year={2011},
organization={IEEE}
}

Abstract

An automatic speech recognition system has modules that depend on the language and, while there are many public resources for some languages (eg, English and Japanese), the resources for Brazilian Portuguese (BP) are still limited. This work describes

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BibTeX

@article{neto2011free,
title={Free tools and resources for Brazilian Portuguese speech recognition},
author={Neto, Nelson and Patrick, Carlos and Klautau, Aldebaro and Trancoso, Isabel},
journal={Journal of the Brazilian Computer Society},
volume={17},
number={1},
pages={53–68},
year={2011},
publisher={Springer}
}

Abstract

Um sistema de reconhecimento automático de voz é composto por módulos dependentes da lıngua. Enquanto existem muitos recursos públicos para algumas lınguas, como Inglês e Japonês, os recursos para o Português Brasileiro (PB) ainda sao escassos.

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BibTeX

@article{oliveira2011recursos,
title={Recursos para desenvolvimento de aplicativos com suporte a reconhecimento de voz para desktop e sistemas embarcados},
author={Oliveira, Rafael and Batista, Pedro and Neto, Nelson and Klautau, Aldebaro},
journal={12o F{\’o}rum Internacional de Software Livre},
year={2011}
}

Abstract

Digital subscriber lines (DSLs) technology is vastly used for high-speed data transmission. Crosstalk is one of the main problems in DSL. The research community has done extensive work on how to optimize spectrum allocation across DSL frequencies and

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BibTeX

@article{moraes2010semiblind,
title={Semiblind spectrum balancing for DSL},
author={Moraes, Rodrigo B and Dortschy, Boris and Klautau, Aldebaro and i Riu, Jaume Rius},
journal={IEEE Transactions on Signal Processing},
volume={58},
number={7},
pages={3717–3727},
year={2010},
publisher={IEEE}
}

Abstract

Most works in power systems event classification concern classifying an event according to the morphology of the corresponding waveform. An important and even more difficult problem is the classification of the event underlying cause. However, the lack of

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BibTeX

@article{morais2010framework,
title={A framework for evaluating automatic classification of underlying causes of disturbances and its application to short-circuit faults},
author={Morais, Jefferson and Pires, Yomara and Cardoso Jr, Claudomir and Klautau, Aldebaro},
journal={IEEE Transactions on Power Delivery},
volume={25},
number={4},
pages={2083–2094},
year={2010},
publisher={IEEE}
}

Abstract

The broadband capacity of the twisted-pair lines strongly varies within the copper access network. It is therefore important to assess the ability of a digital subscriber line (DSL) to support the DSL services prior to deployment. This task is handled by the line qualification

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BibTeX

@article{sales2010line,
title={Line topology identification using multiobjective evolutionary computation},
author={Sales, Claudomiro and Rodrigues, Roberto M and Lindqvist, Fredrik and Costa, Joao and Klautau, Aldebaro and Ericson, Klas and i Riu, Jaume Rius and Borjesson, Per Ola},
journal={IEEE Transactions on Instrumentation and Measurement},
volume={59},
number={3},
pages={715–729},
year={2010},
publisher={IEEE}
}

Abstract

The proper management of the signal to noise ratio margin is important for improving the stability of digital subscriber line (DSL) networks and increasing the customer satisfaction regarding services such as triple-play. This work presents a novel algorithm for

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BibTeX

@inproceedings{monteiro2010algorithm,
title={An algorithm for improved stability of DSL networks using spectrum balancing},
author={Monteiro, Marcio and Gomes, Ana and Lindqvist, Neiva and Dortschy, Boris and Klautau, Aldebaro},
booktitle={Global Telecommunications Conference (GLOBECOM 2010), 2010 IEEE},
pages={1–6},
year={2010},
organization={IEEE}
}

Abstract

This paper describes an impulse noise measurement system for digital subscriber line channels composed by open hardware/software elements developed using the universal software radio peripheral and GNU is not Unix Radio. The proposed system

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BibTeX

@inproceedings{acatauassu2010dsl,
title={DSL Impulse Noise Measurement System Implemented in USRP and GNU Radio},
author={Acatauassu, Diogo and Mesquita, Igor and Muller, Francisco and Klautau, Aldebaro},
booktitle={Telecommunications (AICT), 2010 Sixth Advanced International Conference on},
pages={178–181},
year={2010},
organization={IEEE}
}

Abstract

This work is part of the effort to develop a speech recognition system for Brazilian Portuguese. The resources for the training and test stages of this system, such as corpora, pronunciation dictionary, language and acoustic models, are publicly available. Here, an

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BibTeX

@article{silva2010open,
title={An open-source speech recognizer for Brazilian Portuguese with a windows programming interface},
author={Silva, Patrick and Batista, Pedro and Neto, Nelson and Klautau, Aldebaro},
journal={Computational Processing of the Portuguese Language},
pages={128–131},
year={2010},
publisher={Springer}
}

Abstract

Métodos/Eventos Descriçao Básica SREngine Método para carregar e inicializar o reconhecedor loadGrammar Método para carregar gramática SAPI XML addGrammar Método para carregar gramática nativa do Julius startRecognition Método para iniciar o

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BibTeX

@misc{neto2010reconhecedor,
title={Um Reconhecedor de Voz Livre para Portugu{\^e}s Brasileiro com Interface de Programa{\c{c}}{\~a}o},
author={Neto, Nelson and Silva, Carlos and Batista, Pedro and Klautau, Aldebaro and de Sinais, Laborat{\’o}rio de Processamento},
year={2010},
publisher={Agosto}
}

Abstract

Text-to-speech (TTS) is currently a mature technology that is used in many applications. Some modules of a TTS depend on the language and, while there are many public resources for English, the resources for some underrepresented languages are still

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BibTeX

@inproceedings{couto2010open,
title={An open source HMM-based text-to-speech system for Brazilian Portuguese},
author={Couto, Igor and Neto, Nelson and Tadaiesky, Vincent and Klautau, Aldebaro and Maia, Ranniery},
booktitle={7th international telecommunications symposium},
year={2010}
}

Abstract

The development and assessment of spectrum management methods for the copper access network are usually conducted under the assumption of accurate channel information. Acquiring such information implies, in practice, estimation of the crosstalk

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BibTeX

@article{lindqvist2010impact,
title={Impact of crosstalk channel estimation on the DSM performance for DSL networks},
author={Lindqvist, Neiva and Lindqvist, Fredrik and Monteiro, Marcio and Dortschy, Boris and Pelaes, Evaldo and Klautau, Aldebaro},
journal={EURASIP Journal on Advances in Signal Processing},
volume={2010},
pages={2},
year={2010},
publisher={Hindawi Publishing Corp.}
}

Abstract

The International Conference on Computational Processing of Portuguese—PROPOR—is the main event in the area of natural language processing that is focused on Portuguese and the theoretical and technological issues related to this language. It welcomes

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BibTeX

@book{klautau2010computational,
title={Computational Processing of the Portuguese Language},
author={Klautau, Aldebaro and Vieira, Renata and de Lima, Vera L{\’u}cia Strube and Pardo, Thiago AS},
year={2010},
publisher={Springer-Verlag Berlin Heidelberg}
}

Abstract

There are many spectrum balancing algorithms to combat the deleterious impact of crosstalk interference in digital subscriber lines (DSL) networks. These algorithms aim to find a unique operating point by optimizing the power spectral densities (PSDs) of the modems.

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BibTeX

@article{bezerra2010evolutionary,
title={An evolutionary algorithm for improved diversity in DSL spectrum balancing solutions},
author={Bezerra, Johelden and Klautau, Aldebaro and Monteiro, Marcio and Pelaes, Evaldo and Medeiros, Eduardo and Dortschy, Boris},
journal={EURASIP Journal on Advances in Signal Processing},
volume={2010},
pages={41},
year={2010},
publisher={Hindawi Publishing Corp.}
}

Abstract

This work proposes a method for the evaluation of the effectiveness of adopting dynamic spectral management (DSM) algorithms in different DSL scenarios. In the last years several DSM algorithms emerged in the literature but their comparison has been typically

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BibTeX

@article{smitheffectiveness,
title={On the Effectiveness of Dynamic Spectrum Management Algorithms in xDSL Networks},
author={Smith, Fernanda and M{\”u}ller, Francisco and Klautau, Aldebaro and Pelaes, Evaldo and Monteiro, Marcio and Dortschy, Boris}
}

Abstract

Wireless sensor networks has been growing and brings with it many alternatives which facilitates and turn possible some tasks, like monitoring places which access is not so easy, it is possible joining small sensors with wireless technology. The sensors to this tasks

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BibTeX

@inproceedings{correa2010wireless,
title={A wireless sensor network for monitoring the sound of animals in tropical forests},
author={Correa, Ilan S and Freitas, Lilian C and Costa, Joao Cris{\’o}stomo and Klautau, Aldebaro},
booktitle={10th Microelectronics Students Forum (SForum)},
year={2010}
}

Abstract

Spectrum balancing (SB) techniques optimize transmission and can significantly improve digital subscriber lines (DSL) services. In the literature, the DSL system optimization is typically formulated as a rate maximization problem. However, there is an increasing

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BibTeX

@inproceedings{monteiro2009spectrum,
title={Spectrum balancing algorithms for power minimization in DSL networks},
author={Monteiro, Marcio and Lindqvist, Neiva and Klautau, Aldebaro},
booktitle={Communications, 2009. ICC’09. IEEE International Conference on},
pages={1–5},
year={2009},
organization={IEEE}
}

Abstract

This paper evaluates the capacity of MIMO DSL systems up to 100 MHz using short loops (50 and 200 meters) based on measured channel data. The experimental results show that these systems have capacities as high as 0.77 Gbps for the 50 m loop, for

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BibTeX

@inproceedings{acatauassu2009capacity,
title={Capacity of MIMO DSL systems using 100 MHZ measured channel data},
author={Acatauass{\’u}, Diogo and Muller, Francisco CBF and Klautau, Aldebaro},
booktitle={Telecommunications, 2009. ICT’09. International Conference on},
pages={266–269},
year={2009},
organization={IEEE}
}

Abstract

This paper investigates practical aspects associated to the adoption of dynamic spectrum management (DSM) in existing digital subscriber lines (DSL) access networks. A standard-compliant crosstalk estimation method is utilized in order to retrieve the crosstalk

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BibTeX

@inproceedings{medeiros2009dsm,
title={DSM performance on practical DSL systems based on estimated crosstalk channel information},
author={Medeiros, Eduardo and Lindqvist, Neiva and Monteiro, Marcio and Abrahim, Harney and Lindqvist, Fredrik and Dortschy, Boris and Klautau, Aldebaro},
booktitle={Signal Processing Conference, 2009 17th European},
pages={2092–2096},
year={2009},
organization={IEEE}
}

Abstract

This paper presents a performance analysis of an ultra wideband (UWB) communication system based on Multiband Orthogonal Frequency Division Multiplexing (MB-OFDM) in the presence of narrowband interference. Although OFDM-based systems

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BibTeX

@inproceedings{muller2009performance,
title={Performance analysis of a multiband OFDM UWB system in the presence of narrowband interference},
author={Muller, Francisco CBF and Klautau, Aldebaro and Da Silva, Claudio RCM},
booktitle={Global Telecommunications Conference, 2009. GLOBECOM 2009. IEEE},
pages={1–5},
year={2009},
organization={IEEE}
}

Abstract

This work discusses the integration of available technologies for developing spoken dialog systems in Brazilian Portuguese. As a proof-of-concept, it describes a system for non-visual and on-line Web search on Windows. The prototype system is based on

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BibTeX

@inproceedings{morais2009tecnologias,
title={Tecnologias para o desenvolvimento de sistemas de di{\’a}logo falado em Portugu{\^e}s Brasileiro},
author={Morais, Jefferson and Neto, Nelson and Klautau, Aldebaro},
booktitle={7th Brazilian Symposium in Information and Human Language Technology},
year={2009}
}

Abstract

This work presents a new version of LaPSTalk: a computer-assisted software for English language learning. All the speech interfaces (recognition and synthesis) were implemented using the Microsoft Speech Application Development (SAPI 5.1) toolkit. Also,

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BibTeX

@article{siravenha2009computer,
title={A computer-assisted learning software using speech synthesis and recognition in Brazilian Portuguese},
author={Siravenha, Ana and Neto, Nelson and Macedo, Valqu{\’\i}ria and Klautau, Aldebaro},
journal={Interactive Computer Aided Blended Learning},
pages={1–5},
year={2009}
}

Abstract

This work presents an on-going project that consists in providing low-cost telephony services in remote areas in the Amazon region, North Brazil. The idea is to build GSM networks using open-source and open-hardware projects, such as: OpenBTS,

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BibTeX

@inproceedings{cabral2009low,
title={Low-cost gsm telephony in the amazon region based on open-source/open-hardware projects},
author={Cabral, Marcel and Almeida, Igor and Melo, Carlos and Klautau, Aldebaro},
booktitle={Communications, 2009. LATINCOM’09. IEEE Latin-American Conference on},
pages={1–6},
year={2009},
organization={IEEE}
}

Abstract

This work presents two approaches to the problem of automatic modulation classification in cognitive radios. The first approach deals with classifying distinct QAM modulations. The proposed solution consists of a SVM classifier that uses as input

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BibTeX

@inproceedings{freitas2009automatic,
title={Automatic modulation classification for cognitive radio systems: Results for the symbol and waveform domains},
author={Freitas, Lilian C and Cardoso, Claudomir and Muller, Francisco CBF and Costa, Joao WA and Klautau, Aldebaro},
booktitle={Communications, 2009. LATINCOM’09. IEEE Latin-American Conference on},
pages={1–6},
year={2009},
organization={IEEE}
}

Abstract

Data mining can play a fundamental role in modern power systems. However, the companies in this area still face several difficulties to benefit from data mining. A major problem is to extract useful information from the currently available non-labeled digitized

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BibTeX

@incollection{pires2009data,
title={Data mining applied to the electric power industry: classification of short-circuit faults in transmission lines},
author={Pires, Yomara and Morais, Jefferson and Cardoso, Claudomir and Klautau, Aldebaro},
booktitle={Innovative Applications in Data Mining},
pages={107–122},
year={2009},
publisher={Springer}
}

Abstract

I. INTRODUCTION CROSSTALK noise from similar digital services of physically adjacent loops is the primary impairment to send digital information through usual transmission lines, such as twisted-pair loops, which are nowadays used as inexpensive channels for last mile Internet

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BibTeX

@inproceedings{alcantara2009mtl,
title={A MTL transmission matrix method for transmission-lines with differential setup},
author={Alcantara, Licinius DS and Costa, Jo{\~a}o CW Albuquerque and Dortschy, Boris and Klautau, Aldebaro},
booktitle={Microwave and Optoelectronics Conference (IMOC), 2009 SBMO/IEEE MTT-S International},
pages={363–367},
year={2009},
organization={IEEE}
}

Abstract

The growth of available data in the electric power industry motivates the adoption of data mining techniques. However, the companies in this area still face several difficulties to benefit from data mining. One of the reasons is that mining power systems data is an

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BibTeX

@incollection{morais2009overview,
title={An overview of data mining techniques applied to power systems},
author={Morais, Jefferson and Pires, Yomara and Cardoso, Claudomir and Klautau, Aldebaro},
booktitle={Data Mining and Knowledge Discovery in Real Life Applications},
year={2009},
publisher={InTech}
}

Abstract

Data mining can play a fundamental role in modern power systems. However, a major problem is to extract useful information from the currently available non-labeled digitized time series. This work proposes a new methodology based on hierarchical

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BibTeX

@inproceedings{cardoso2008hierarchical,
title={Hierarchical Agglomerative clustering of short-circuit faults in transmission lines},
author={Cardoso, Claudomir and Pires, Yomara and Morais, Jefferson and Klautau, Aldebaro},
booktitle={Neural Networks, 2008. SBRN’08. 10th Brazilian Symposium on},
pages={87–92},
year={2008},
organization={IEEE}
}

Abstract

Digital subscriber lines (DSL) are today one of the most important
means for delivering high-speed data transmission. An emerging technique
for dealing with one of the technologys most harmful problems

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BibTeX

@inproceedings{moraes2008semi,
title={Semi-blind power allocation for digital subscriber lines},
author={Moraes, Rodrigo and Dortschy, Boris and Klautau, Aldebaro and i Riu, J Rius},
booktitle={Communications, 2008. ICC’08. IEEE International Conference on},
pages={1420–1425},
year={2008},
organization={IEEE}
}

Abstract

Digital Subscriber Lines (DSL) are today one of the most important means for delivering high-speed data transmission. Dynamic Spectrum Management (DSM) is an emerging technique for dealing with crosstalk, one of the technologys most harmful”

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BibTeX

@inproceedings{moraes2008optimal,
title={Optimal solution for the fixed margin problem in digital subscriber lines},
author={Moraes, Rodrigo and Dortschy, Boris and Klautau, Aldebaro and Zampolo, Ronaldo and i Riu, Jaume Rius},
booktitle={Communications, Control and Signal Processing, 2008. ISCCSP 2008. 3rd International Symposium on},
pages={1395–1399},
year={2008},
organization={IEEE}
}

Abstract

The development and assessment of spectrum management methods for the copper access network are usually conducted under the assumption of accurate channel information. Acquiring such information implies, in practice, estimation of the crosstalk

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BibTeX

@inproceedings{lindqvist2008impact,
title={Impact of crosstalk estimation on the dynamic spectrum management performance},
author={Lindqvist, Neiva and Lindqvist, Fredrik and Dortschy, Boris and Pelaes, Evaldo and Klautau, Aldebaro},
booktitle={Global Telecommunications Conference, 2008. IEEE GLOBECOM 2008. IEEE},
pages={1–5},
year={2008},
organization={IEEE}
}

Abstract

The development and assessment of spectrum management methods for the copper access network are usually conducted under the assumption of accurate channel information. Acquiring such information implies, in practice, estimation of the crosstalk

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BibTeX

@inproceedings{neiva2008impact,
title={Impact of crosstalk estimation on the dynamic spectrum management performance},
author={Neiva, Lindqvist and Lindqvist, Fredrik and Dortschy, Boris and Pelaes, Evaldo and Klautau, Aldebaro},
booktitle={IEEE Global Communication-GLOBECOM 2008},
year={2008},
organization={IEEE Press}
}

Abstract

This work describes GASpeech: a framework centered on genetic algorithms for automatically estimating the input parameters of Klatts speech synthesizer. GASpeech aims to speed up the process of speech imitation (or utterance copy)

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BibTeX

@inproceedings{borges2008gaspeech,
title={GASpeech: A framework for automatically estimating input parameters of Klatt’s speech synthesizer},
author={Borges, Jos{\’e} and Couto, Igor and Oliveira, Fab{\’\i}ola and Imbiriba, Tales and Klautau, Aldebaro},
booktitle={Neural Networks, 2008. SBRN’08. 10th Brazilian Symposium on},
pages={81–86},
year={2008},
organization={IEEE}
}

Abstract

A conversao de uma seqüência de caracteres em seqüências de fones é um importante pré-requisito para serviços que envolvem reconhecimento e/ou sıntese de voz. Contudo, a tarefa nao é trivial e diversas técnicas de conversao vêm sendo adotadas ao

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BibTeX

@inproceedings{siravenha2008uso,
title={Uso de regras fonol{\’o}gicas com determina{\c{c}}ao de vogal t{\^o}nica para conversao grafema-fone em portugu{\^e}s brasileiro},
author={Siravenha, Ana and Neto, Nelson and Macedo, Valqu{\i}ria and Klautau, Aldebaro},
booktitle={7th International Information and Telecommunication Technologies Symposium},
pages={1–6},
year={2008}
}

Abstract

CAI (Computer Assisted Instruction) is a learning process with the aid of computers. In the last 40 years, there was an exponential growth in the use of computers as providers of instructions. During this fast technological revolution, the CAI has become more refined and

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BibTeX

@article{neto2008computer,
title={A computer-assisted learning software to help teaching english to brazilians},
author={Neto, Nelson and Siravenha, Ana and Macedo, Valqu{\’\i}ria and Klautau, Aldebaro},
journal={Applications of Portuguese Speech and Language Technologies-Propor 2008 Special Session},
pages={8},
year={2008}
}

Abstract

Este trabalho apresenta uma avaliaç ao de classificadores de modulaçao digital em sensoriamento espectral de rádio cognitivo. Para extraçao das caracterısticas da modulaçao digital é utilizada análise de correlaçao espectral cıclica, a qual tem

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BibTeX

@article{freitas2008classificadores,
title={Classificadores de modula{\c{c}}{\~a}o digital em sensoriamento espectral de r{\’a}dio cognitivo},
author={Freitas, Lilian C and Klautau, Aldebaro and Costa, JCWA},
journal={Simp{\’o}sio Brasileiro de Telecomunica{\c{c}}{\~o}es (SBrT) 2008},
year={2008}
}

Abstract

Speech processing is a data-driven technology that relies on public corpora and associated resources. In contrast to languages such as English, there are few resources for Brazilian Portuguese (BP). This work describes efforts toward decreasing such gap and

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BibTeX

@article{neto2008spoltech,
title={Spoltech and ogi-22 baseline systems for speech recognition in brazilian portuguese},
author={Neto, Nelson and Silva, Patrick and Klautau, Aldebaro and Adami, Andre},
journal={Lecture Notes in Computer Science},
volume={5190},
pages={256},
year={2008},
publisher={Springer}
}

Abstract

Speech processing is a data-driven technology that relies on public corpora and associated resources. In contrast to languages such as English, there are few resources for Brazilian Portuguese (BP). This work describes efforts toward decreasing such gap and

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BibTeX

@article{silva2008speech,
title={Speech recognition for brazilian portuguese using the spoltech and OGI-22 corpora},
author={Silva, Patrick and Neto, Nelson and Klautau, Aldebaro and Adami, Andre and Trancoso, Isabel},
journal={XXVI Simp{\’o}sio Brasileiro de Telecomunica{\c{c}}oes-SBrt},
volume={2008},
year={2008},
publisher={Citeseer}
}

Abstract

This work presents BrDSLWizard, a software to obtain and monitor DSL modems, including the evaluation of the operating margin. Margin fluctuations indicate changes in the condition of the DSL channel, such as increase of the crosstalk interference. BrDSLWizard

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BibTeX

@article{macapuna2008software,
title={A software for evaluating the operating margin of dsl modems},
author={Macapuna, Carlos and Medeiros, Eduardo and Klautau, Aldebaro},
journal={Proc. XXVI Simp{\’o}sio Brasileiro de Telecomunica{\c{c}}oes-SBrT},
year={2008}
}

Abstract

Data mining can play a fundamental role in modern power systems. However, the companies in this area still face several difficulties to benefit from data mining. A major problem is to extract useful information from the currently available non-labeled digitized

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BibTeX

@inproceedings{morais2007data,
title={Data mining applied to the electric power industry: Classification of short-circuit faults in transmission lines},
author={Morais, Jefferson and Pires, Yomara and Cardoso, Claudomir and Klautau, Aldebaro},
booktitle={Intelligent Systems Design and Applications, 2007. ISDA 2007. Seventh International Conference on},
pages={943–948},
year={2007},
organization={IEEE}
}

Abstract

In most works published so far, dynamic spectrum management (DSM) techniques are simulated assuming a single service (eg ADSL) and classical copper-pair channel models described in standards for spectrum management. This work presents an

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BibTeX

@article{fonseca2007evaluation,
title={Evaluation of DSM performance with mixed DSL services and measured crosstalk channels},
author={Fonseca, Neiva and Neves, Darlene and Gomes, Ana Claudia and Conte, M{\’a}rcio and Dortschy, Boris and Ericson, Klas and Riu, Jaume Rius I and Pelaes, Evaldo and Klautau, Aldebaro},
journal={Proceedings of the 25th Simp{\’o}sio Brasileiro de Telecomunica{\c{c}}oes (SBrT’07)},
year={2007}
}

Abstract

O trabalho emprega técnicas de Inteligência Computacional procurando facilitar a análise e o diagnóstico de problemas em Qualidade de Energia, pois várias causas, desde naturais até manobras planejadas, podem comprometer essa qualidade e acarretar

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BibTeX

@article{borges2007inteligencia,
title={Intelig{\^e}ncia Artificial Aplicada {\`a} Supervis{\~a}o da Qualidade de Energia},
author={Borges, L and Klautau, Aldebaro},
journal={Revista Cient{\’\i}fica da UFPA},
year={2007}
}

Abstract

This work concerns automatic classification of short circuits in transmission lines. These faults are responsible for the majority of the disturbances and cascading blackouts. Each short circuit is represented by a sequence (time-series) and both online (for each short

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BibTeX

@inproceedings{morais2007experimental,
title={An experimental evaluation of automatic classification of sequences representing short circuits in transmission lines},
author={Morais, Jefferson and Pires, Yomara and Cardoso, Claudomir and Klautau, Aldebaro},
booktitle={Brazilian Conference on Neural Networks (CBRN)},
year={2007}
}

Abstract

Speech processing is a data-driven technology that relies on public corpora and associated resources. In contrast to languages such as English, there are few resources for Brazilian Portuguese (BP). Consequently, there are no publicly available scripts to design

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BibTeX

@inproceedings{hosn2006new,
title={New resources for brazilian portuguese: Results for grapheme-to-phoneme and phone classification},
author={Hosn, Chadia and Baptista, Luiz Alberto and Imbiriba, Tales and Klautau, Aldebaro},
booktitle={Telecommunications Symposium, 2006 International},
pages={477–482},
year={2006},
organization={IEEE}
}

Abstract

The paper presents preliminary results of a new framework for automatically extracting the input parameters of a class of synthesizers. The framework allows to speed up the process of utterance copy (or speech imitation), where one has to find the model

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BibTeX

@inproceedings{figueiredo2006automatically,
title={Automatically estimating the input parameters of formant-based speech synthesizers},
author={Figueiredo, Aline and Imbiriba, Tales and Bruckert, Edward and Klautau, Aldebaro},
booktitle={Workshop de Tecnologia da Informa{\c{c}}{\~a}o e da Linguagem Humana-TIL 2006. October, 23-27},
year={2006}
}

Abstract

The Gaussian mixture model (GMM) is the main technique used in speaker recognition systems. However, in tasks other than speaker recognition, GMM is often outperformed by modern classifiers, such as support vector machines (SVM). This work

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BibTeX

@inproceedings{imbiriba2005applying,
title={Applying Discriminative Learning to Speaker Verification},
author={Imbiriba, Tales and Marinho, Rafael and Castro, Adalbery and Klautau, Aldebaro},
booktitle={Congresso Brasileiro de Computa{\c{c}}ao-Workshop TIL},
year={2005}
}

Abstract

Real-world power quality (PQ) events usually are infrequent and composing a dataset of significant size is a difficult task. Using simulators to generate data in wellcontrolled conditions is a very useful and popular option. This work presents a

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BibTeX

@inproceedings{pires2005framework,
title={A framework for evaluating data mining techniques applied to power quality},
author={Pires, Yomara and Santos, Andreia and Borges, Jose and Carvalho, Antonio and Nunes, Marcus Vinicius Alves and Santoso, Surya and Klautau, Aldebaro},
booktitle={Brazilian Conference on Neural Networks (CBRN)},
year={2005}
}

Abstract

Speech is a natural interface for human-machine communication. Speech (or voice) technology is a well-developed field when one considers the international community. There is a wide variety of academic and industrial software. The majority of them assumes a

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BibTeX

@inproceedings{neto2005desenvolvimento,
title={Desenvolvimento de software livre usando reconhecimento e s{\’\i}ntese de voz: O estado da arte para o Portugu{\^e}s Brasileiro},
author={Neto, N and Sousa, Erick and Macedo, Valqu{\i}ria and Adami, A and Klautau, Aldebaro},
booktitle={6th forum internacional software livre},
year={2005}
}

Abstract

This work presents some steps towards the development of a large vocabulary continuousspeech recognition system for Brazilian Portuguese, with a vocabulary of more than 60 thousand words. The paper discusses the creation of a phonetic dictionary, with

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BibTeX

@inproceedings{silva2005desenvolvimento,
title={Desenvolvimento de um sistema de reconhecimento autom{\’a}tico de voz cont{\’\i}nua com grande vocabul{\’a}rio para o Portugu{\^e}s Brasileiro},
author={Silva, E and Baptista, Luiz and Fernandes, Helane and Klautau, Aldebaro},
booktitle={XXV congresso da sociedade Brasileira de computa{\c{c}}{\~a}o},
year={2005}
}

Abstract

This paper describes an open source framework for developing speaker recognition systems. Among other features, it supports kernel classifiers, such as the support and relevance vector machines. The paper also presents results for the IME corpus using

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BibTeX

@inproceedings{imbiriba2004gmm,
title={GMM and kernel-based speaker recognition with the ISIP toolkit},
author={Imbiriba, Tales and Klautau, Aldebaro and Parihar, Naveen and Raghavan, Sridhar and Picone, Joseph},
booktitle={Machine Learning for Signal Processing, 2004. Proceedings of the 2004 14th IEEE Signal Processing Society Workshop},
pages={371–380},
year={2004},
organization={IEEE}
}

Abstract

Este trabalho apresenta resultados preliminares acerca do uso de modelos estatísticos N-grama para o português brasileiro. O mesmo se insere no âmbito do desenvolvimento de um sistema de reconhecimento de voz com suporte a grandes vocabulários, onde a

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BibTeX

@inproceedings{silva2004modelos,
title={Modelos de linguagem n-grama para reconhecimento de voz com grande vocabul{\’a}rio},
author={Silva, E and Pantoja, Marcus and Celid{\^o}nio, Jackline and Klautau, Aldebaro},
booktitle={III workshop em tecnologia da informa{\c{c}}{\~a}o e da linguagem humana},
year={2004}
}

Abstract

We consider the problem of multiclass classification. Our main thesis is that a simple one-vs-all” scheme is as accurate as any other approach

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BibTeX

@article{rifkin2004defense,
title={In defense of one-vs-all classification},
author={Rifkin, Ryan and Klautau, Aldebaro},
journal={Journal of machine learning research},
volume={5},
number={Jan},
pages={101–141},
year={2004}
}

Abstract

We investigate feature selection applied to automatic speech recognition (ASR) systems. We focus on systems based on support vector machines (SVM), which can naturally use features optimized for each classifier. We present a new method for feature

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BibTeX

@inproceedings{klautau2003mining,
title={Mining speech: automatic selection of heterogeneous features using boosting},
author={Klautau, Aldebaro},
booktitle={Acoustics, Speech, and Signal Processing, 2003. Proceedings.(ICASSP’03). 2003 IEEE International Conference on},
volume={2},
pages={II–13},
year={2003},
organization={IEEE}
}

Abstract

A common way of constructing a multiclass classifier is by combining the outputs of several binary ones, according to an error-correcting output code (ECOC) scheme. The combination is typically done via a simple nearest-neighbor rule that finds the class that is

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BibTeX

@article{klautau2003nearest,
title={On nearest-neighbor error-correcting output codes with application to all-pairs multiclass support vector machines},
author={Klautau, Aldebaro and Jevti{\’c}, Nikola and Orlitsky, Alon},
journal={Journal of Machine Learning Research},
volume={4},
number={Apr},
pages={1–15},
year={2003}
}

Abstract

We show that a classifier based on Gaussian mixture models (GMM) can be trained discriminatively to improve accuracy. We describe a training procedure based on the extended Baum-Welch algorithm used in speech recognition. We also compare the

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BibTeX

@inproceedings{klautau2003discriminative,
title={Discriminative Gaussian mixture models: A comparison with kernel classifiers},
author={Klautau, Aldebaro and Jevtic, Nikola and Orlitsky, Alon},
booktitle={Proceedings of the 20th International Conference on Machine Learning (ICML-03)},
pages={353–360},
year={2003}
}

Abstract

Many applications require classification of examples into one of several classes. A common way of designing such classifiers is to determine the class based on the outputs of several binary classifiers. We consider some of the most popular methods for combining

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BibTeX

@inproceedings{klautau2002combined,
title={Combined binary classifiers with applications to speech recognition.},
author={Klautau, Aldebaro and Jevtic, Nikola and Orlitsky, Alon},
booktitle={INTERSPEECH},
year={2002}
}

Abstract

Most speech recognition systems search through large finite state machines to find the most likely path, or hypothesis. Efficient search in these large spaces requires pruning of some hypotheses. Popular pruning techniques include probability pruning which keeps only

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BibTeX

@inproceedings{jevtic2001estimated,
title={Estimated rank pruning and Java-based speech recognition},
author={Jevtic, Nikola and Klautau, Aldebaro and Orlitsky, Alon},
booktitle={Automatic Speech Recognition and Understanding, 2001. ASRU’01. IEEE Workshop on},
pages={401–404},
year={2001},
organization={IEEE}
}

Abstract

We propose a new architecture for deploying speech recognition over the Internet. The client performs the recognition, but is assisted by the server who computes the speech parameters. To demonstrate the architecture, we developed a Java-based Web-navigation

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BibTeX

@inproceedings{klautau2000server,
title={Server-assisted speech recognition over the Internet},
author={Klautau, Aldebaro and Jevtic, Nikola and Orlitsky, Alon},
booktitle={Acoustics, Speech, and Signal Processing, 2000. ICASSP’00. Proceedings. 2000 IEEE International Conference on},
volume={6},
pages={3690–3693},
year={2000},
organization={IEEE}
}

Abstract

Introduction Several speech processing algorithms assume the signal is stationary during short intervals (approximately 20 to 30 ms). This assumption is valid for several applications, but it is too restrictive in some contexts. This work investigates the application

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BibTeX

@article{klautau2000frequency,
title={Frequency Tracking: LMS and RLS Applied to Speech Formant Estimation},
author={Klautau, Aldebaro},
year={2000},
publisher={Citeseer}
}

Abstract

Long-term ECG monitoring demands a bit rate of around 200 bps with acceptable distortion. Vector quantization (VQ) techniques allow one to reach that performance, despite the high computational effort. The most time-consuming stage in the VQ is the search for the

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BibTeX

@inproceedings{bertonha1993ecg,
title={ECG data compression with vector quantization using k-dimensional tree for fast search},
author={Bertonha, Eduardo and Zanchin, Carlos I and Klautau, Aldebaro},
booktitle={Computers in Cardiology 1993, Proceedings.},
pages={515–518},
year={1993},
organization={IEEE}
}

Abstract

Monitoramento de integridade estrutural tornou-se uma tecnologia muito importante na engenharia civil e é altamente dependente de avanços na instrumentação, comunicações e microeletrônica. Este trabalho apresenta um sistema de monitoramento

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BibTeX

@article{ataide11rede,
title={Rede de Sensores para Monitoramento de Integridade Estrutural: Monitoramento On-line de Torres de Linha de Transmiss{\~a}o},
author={Ataide, Rodrigo Williams and Castro, Adalbery and Souza, Marco and Souza, Remo and Klautau, Aldebaro},
journal={Revista de Inicia{\c{c}}{\~a}o Cient{\’\i}fica},
volume={11},
number={4}
}