Segunda/Monday - Sexta/Friday (8:00/8:00AM – 18:00/6:00PM)
+55 91 3201-7181
lasse@ufpa.br

Publicações

Abstract

Digital representations of the real world are being used in many applications, such as augmented reality. 6G systems will not only support use cases that rely on virtual worlds but also benefit from their rich contextual information to improve performance and reduce communication overhead. This paper focuses on the simulation of 6G systems that rely on a 3D representation of the environment, as captured by cameras and other sensors. We present new strategies for obtaining paired MIMO channels and multimodal data. We also discuss trade-offs between speed and accuracy when generating channels via ray tracing. We finally provide beam selection simulation results to assess the proposed methodology.

Quick access

[PDF]

BibTeX

@article{oliveira_bastos_trindade_frazão_nascimento_klautau_muller_gomes_2021,
title={Simulation of Machine Learning-based 6G Systems in Virtual Worlds},
volume={2},
number={4},
journal={ITU Journal on Future and Evolving Technologies},
author={Oliveira, Ailton and Bastos, Felipe and Trindade, Isabela and Frazão, Walter and Nascimento, Arthur and Klautau, Aldebaro and Muller, Francisco and Gomes, Diego},
year={2021},
pages={113–123}}

Abstract

This work proposes a compression method developed to transport radio signals over a centralized radio access network using a functional split in which the fronthaul transports frequency-domain samples. The proposed method allows detecting which subcarriers from an LTE/NR OFDM symbol are inactive to avoid sending them over the fronthaul, hence decreasing the required throughput and making it vary with the radio usage. The proposed method was evaluated in different scenarios, and the results were analyzed in terms of user equipment goodput and fronthaul traffic. The simulations show a significant reduction in the fronthaul traffic, especially when the radio usage is low.

Quick access

[PDF]

BibTeX

@ARTICLE{9439518,
author={Nahum, Cleverson and Ramalho, Leonardo and Klautau, Aldebaro and Medeiros, Eduardo and Almeida, Igor and Trojer, Elmar},
journal={IEEE Communications Letters},
title={Functional Split and Frequency-Domain Processing for Fronthaul Traffic Reduction},
year={2021},
volume={25},
number={8},
pages={2758-2762}}

Abstract

Applications of Reinforcement Learning (RL) are increasingly relevant in the context of future networks. However, although there is a great availability of environments for other research areas such as computer vision, there is a lack of good ones for telecommunication purposes. This paper proposes a Beam-Selection MiniGrid, based on Minimalist Gridworld environment.

Quick access

[PDF]

BibTeX

@article{aben-athar_braun_nascimento_borges_klautau_2021,
title={Beam-Selection MiniGrid Environment for 5G and 6G Networks Applications},
journal={XXXIX SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2021},
author={Aben-Athar, Rebecca and Braun, Carnot and Nascimento, Ingrid and Borges, João and Klautau, Aldebaro},
year={2021},
pages={1–2}}

Abstract

Some 6G use cases include augmented reality and high-fidelity holograms, with this information flowing through the network. Hence, it is expected that 6G systems can feed machine learning algorithms with such context information to optimize communication performance. This paper focuses on the simulation of 6G MIMO systems that rely on a 3-D representation of the environment as captured by cameras and eventually other sensors. We present new and improved Raymobtime datasets, which consist of paired MIMO channels and multimodal data. We also discuss tradeoffs between speed and accuracy when generating channels via ray-tracing. We finally provide results of beam selection and channel estimation to assess the impact of the improvements in the ray-tracing simulation methodology.

Quick access

[PDF]

BibTeX

@article{klautau2021generating,
title={Generating MIMO Channels For 6G Virtual Worlds Using Ray-tracing Simulations},
author={Klautau, Aldebaro and de Oliveira, Ailton and Trindade, Isabela Pamplona and Alves, Wesin},
journal={arXiv preprint arXiv:2106.05377},
year={2021}
}

Abstract

The fifth-generation (5G) cellular networks incorporate a large variety of technologies in order to address very distinct use cases. Assessing these technologies and investigating future alternatives is complicated when one relies only on simulators. 5G testbeds are an important alternative to simulators and many have been recently described, emphasizing aspects such as cloud functionalities, management and orchestration. This work presents a 5G mobile network testbed with a virtualized and orchestrated structure using containers, which focuses on integration to artificial intelligence (AI) applications. The presented testbed uses open-source technologies to deploy and orchestrate the virtual network functions (VNFs) to flexibly create various mobile network scenarios, with distinct fronthaul and backhaul topologies. Distinctive features of the testbed are its relatively low cost and the support to using AI for optimizing the network performance. The paper explains how to deploy the testbed structure and reproduce the presented results with the provided code. AI-based radio access network (RAN) slicing and VNF placement are used as examples of the testbed capabilities.

Quick access

[PDF]

BibTeX

@ARTICLE{9290141,
author={Nahum, Cleverson Veloso and De Nóvoa Martins Pinto, Lucas and Tavares, Virgínia Brioso and Batista, Pedro and Lins, Silvia and Linder, Neiva and Klautau, Aldebaro},
journal={IEEE Access},
title={Testbed for 5G Connected Artificial Intelligence on Virtualized Networks},
year={2020},
volume={8},
number={},
pages={223202-223213}}

Abstract

Cell-free massive multiple-input multiple-output (CF-mMIMO) is one of the components of the fifth generation mobile communications, where a large number of distributed access points (APs) serve many users simultaneously, and provides scalability and high capacity data transmission. However, resource usage increases as the number of APs and user equipment (UEs) grows in the network, and practical systems need to meet the serequirements. In this work, we evaluate resource usage of the fronthaul (FH) link capacity using two precoding methods, zero-forcing and conjugate beamforming, with regards to user data and channel state information (CSI) transmission.

Quick access

[PDF]

BibTeX

@article{nakamura_ramalho_klautau_2020,
title={Fronthaul Requirements Analysis for Cell-Free MIMO},
journal={IV School on Systems and Networks – SSN 2020},
author={Nakamura, Andrey and Ramalho, Leonardo and Klautau, Aldebaro},
year={2020},
pages={1–4}}

Abstract

Satellite tracking techniques are constantly being developed and improved so that stable communication links between satellites and terrestrial stations can be established. However, the implementation of such techniques can be frequently limited due to the complexity in reproducing satisfying test scenarios, manipulating and interpreting signals from those systems. Therefore, this paper proposes a method to manipulate the power signals of a three-phase induction motor (responsible for the movement of an antenna in a satellite tracking system) in order to apply them to a system able to emulate the behavior of the beacon signal (the reference signal for satellites). For that, the hardware project of a beacon and limit switches (LSs) emulators, motor rotation frequency meters, and rotation direction detectors will be presented. This was implemented in a System on-Chip (SoC) FPGA (Field Programmable Gate Array) platform. The described system enables hardware-in-the-loop simulations and the efficient assessment of satellite tracking algorithms.

Quick access

[PDF]

BibTeX

@INPROCEEDINGS{9231170,
author={Conde, Lucas and Souza, Gustavo and Souza, Yuri and Nunes, Flávio and Takeda, Marcos and Castro, Adalbery and Klautau, Aldebaro},
booktitle={2020 International Conference on Computing, Electronics Communications Engineering (iCCECE)},
title={SoC FPGA-based Beacon Emulator Platform for a Three-Axis Satellite Antenna},
year={2020},
volume={},
number={},
pages={217-223}}

Abstract

This article presents an energy consumption analysis of two different emulation scenarios of a GSM (Global System for Mobile) network; one with a traditional computer and another with Raspberry Pi 3. The network is created by open-source software that emulates the main modules of a GSM network, this emulation combined with a radio generator equipment enables calls and message exchange between network users. The CELCOM project designs and implements community networks in digitally isolated regions, the scenarios presented in this article can be applied in works of CELCOM project. The power distribution service of this GSM network, in isolated regions, does not have the required stability to maintain the quality in community networks, creating a demand for an alternative power system. Different scenarios are proposed and analyzed in this work, trying to get a lower energy consumption.

Quick access

[PDF]

BibTeX

@article{couto_leão_castro_muller_klautau_2020,
title={Redução De Consumo De Energia Em Sistemas De Telefonia Comunitária Usando Raspberry Pi},
journal={XI Computer on the Beach – COTB 2020},
author={Couto, Gabriel and Leão, Giovanni and Castro, Lauro and Muller, Francisco and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

This article presents the current stage of the implementation of the PA5Ge, which is a mobile network based on functionalities of the fourth (4G) and fifth (5G) generations, licensed for scientific and experimental purposes in the 700 MHz band. The PA5Ge has modern features such as virtualization of network functions (VNFs) and architecture of Centralized Radio Access Network (C-RAN). One of its objectives is to serve as an experimental platform for academic research in 5G and future networks (B5G). Another objective is to generate know-how for the future use of 4G/5G resources on community networks in locations far from urban centers and not served by commercial operators. In this context, the main contribution of the article is the project description and its steps on the implementation of PA5Ge, encompassing licensing aspects to technicians in order to foster similar initiatives to establish platforms for experimental research in 4G/5G and in the scope of humanitarian engineering through telecommunications.

Quick access

[PDF]

BibTeX

@article{castro_nahum_correa_ramalho_klautau_2020,
title={PA5Ge: Implementação de uma Rede Celular Privada com Funcionalidades 5G no Campus da UFPA},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020},
author={Castro, Lauro and Nahum, Cleverson and Correa, Ilan and Ramalho, Leonardo and Klautau, Aldebaro},
year={2020},
pages={1–5}}

Abstract

Aerial imagery map generation depends on the application of several optimization processes for image quality improvement. This is usually done by proprietary software, which removes the possibility of code customization and often requires expensive licenses. This paper proposes the adoption of an open-source aerial mapping tool as a learning platform in the area of unmanned aerial vehicle (UAV) mapping, posing as an alternative to commercial programs in the study of multispectral aerial images applied to crop health monitoring. The paper discusses the results obtained in the experiments using the different processing methods available at the proposed tool.

Quick access

[PDF]

BibTeX

@article{castro_borges_klautau_pinheiro_shibata_lins_klautau_2020,
title={UAV-Based Crop Monitoring Through Multispectral Image Processing using Open-Source Tools},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020},
author={Castro, Pedro and Borges, João and Klautau, Sofia and Pinheiro, Samya and Shibata, Lucas and Lins, Silvia and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

This paper presents the design of an RF front end for a base transceiver station implemented with a commercial general purpose software defined radio board. This front end helps to decrease the total cost of deploying community networks and the contribution of this paper is to disclose its project and simulation results, as well as discuss the aspects that influenced its design decisions.

Quick access

[PDF]

BibTeX

@article{carneiro_maia_nunes_klautau_ramalho_2020,
title={RF Front End for an SDR-based Community Network in the 700MHz Band},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020},
author={Carneiro, Daniel and Maia, Moacir and Nunes, Flavio and Klautau, Aldebaro and Ramalho, Leonardo},
year={2020},
pages={1–2}}

Abstract

MIMO (multiple-input multiple-output) wireless communication systems play a fundamental role in 5G communications and beyond. This work describes the development of an open source Python package aimed to assist students and researchers in the study of 5G MIMO systems. Its current version includes the ability to estimate the capacity of a MIMO channel for different levels of CSI (channel-state information) available to the transmitter and receiver and the calculation of directivity patterns for antenna arrays. A brief discussion on the conversion of code developed originally in Matlab to Python is included. The major objective is to allow the community to explore, improve and expand this Python package for 5G MIMO processing.

Quick access

[PDF]

BibTeX

@article{shibata_muller_klautau_2020,
title={Open Source Python Package for 5G MIMO Processing},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020},
author={Shibata, Lucas and Muller, Francisco and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

Gather data to test telecommunication systems is an essential step to guarantee the quality of the product, but it can be a slow process and demand a good amount of effort. Having a ready dataset at disposal make things way easier and faster, allowing a developer to focus in more specific stuff. This paper presents an entire multimodal dataset with different kinds of information like: channel communication, urban traffic and obstacles position, got from two simulations made in two different city models: Beijing and Rosslyn. It also includes detailed information on how each data is stored.

Quick access

[PDF]

BibTeX

@article{nascimento_frazão_oliveira_gomes_klautau_2020,
title={MultiModal Dataset for Machine Learning Applied to Telecommunications},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020},
author={Nascimento, Arthur and Frazão, Walter and Oliveira, Ailton and Gomes, Diego and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

System virtualization ensures greater flexibility in telecommunications networks when compared to physical solutions. The centralized radio access network (C-RAN) architecture allows a virtualized mobile network deployment, and it uses fronthaul and backhaul links for component communication. Physical fronthaul and backhaul topologies are a problematic point, as they require the configuration and purchase of multiple routers and switches. This article proposes a C-RAN deployment using the OpenAirInterface platform with virtualized fronthaul and backhaul using Mininet, thus creating a flexible configuration of fronthaul and backhaul topologies for researches.

Quick access

[PDF]

BibTeX

@article{couto_nahum_tavares_pereira_batista_klautau_2020, title={Virtualized C-RAN with Mininet and OAI Supporting Flexible Network Topologies},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020, },
author={Couto, Gabriel and Nahum, Cleverson and Tavares, Virgínia and Pereira, João and Batista, Pedro and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

This paper presents a feasibility study of performing equipment inspection on networked environments by exploring networks specially designed for semantic segmentation task. It is assumed that the neural network needs to be split and the resulting two pieces need to be allocated in two devices. The provided results suggest that the current state of the art on semantic segmentation is not well-suited for the splitted networks applications even in the context of the 5G networks.

Quick access

[PDF]

BibTeX

@article{gonçalves_guerreiro_pinheiro_brito_nascimento_linder_klautau_2020,
title={Splitted Neural Networks for Equipment Inspection: Experiments and Resources},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020,},
author={Gonçalves, Luan and Guerreiro, Tiago and Pinheiro, Samya and Brito, Flávio de and Nascimento, Ingrid and Linder, Neiva and Klautau, Aldebaro},
year={2020},
pages={1–5}}

Abstract

Network Slicing is considered a key mechanism to serve all network clients in a flexible and cost-efficient manner. This concept defines a real network into virtual and independent logical networks allocated according to services and requirements. The software-defined RAN (Radio Access Network) platforms allow the control and administration of RAN, thus providing functionalities such as network slicing and RAN programmability. This paper presents an implementation of a software-defined RAN platform in a Centralized RAN architecture using FlexRAN and OpenAirInterface platform. Furthermore, the network elements were containerized using Docker in an orchestrated scenario using Kubernetes.

Quick access

[PDF]

BibTeX

@article{nóvoa_tavares_nahum_batista_klautau_2020,
title={RAN Slicing using OpenAirInterface and FlexRAN in a Virtualized Scenario},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020, },
author={Nóvoa, Lucas and Tavares, Virgínia and Nahum, Cleverson and Batista, Pedro and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

The Wireless Mesh Network (WMN) allows communication between wireless devices with the a id of multihop wireless mesh routers, while they are within range of the radios, under penalty of data loss. But, long distances, delays, disruptions or disconnections between nodes are a challenge to Wireless Mesh Network. The DTN (Delay / Disruption Tolerant Networking) technology allows the transfer of continuous and quality data in a network, this technology has a data delivery guaranteed by its Store-and-Forward mechanism. This article presents a low-cost and easy implementation of a Delay/Disruption Tolerant Wireless Mesh Network, through WMN associate with DTN. For the easy and low-cost implementation, we use the tools LibreMesh and IBR-DTN, because they are free and have low complexity. The validation of the implementation was through an analysis of Packet Loss and Round Trip Time (RTT) between the Mesh Network with and without the DTN association.

Quick access

[PDF]

BibTeX

@article{tavares_neto_muller_klautau_2020,
title={Delay/Disruption Tolerant Mesh Network Using LibreMesh and IBR-DTN},
journal={XXXVIII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT 2020,},
author={Tavares, Virgínia and Neto, Moacir and Muller, Francisco and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

Channel characterization is one of the most important steps in the design and performance evaluation of a communication system. With the adoption of larger antenna arrays (up to the hundreds, in massive MIMO systems) and millimeter waves, measurement campaigns require expensive equipment to be performed. An alternative approach is touse ray-tracing techniques to accurately obtain MIMO channel responses. For time-varying scenarios, the simulation can be very computationally expensive. An alternative method is to obtain SISO channel responses, and then use the geometric channel model to generate the full MIMO channel for uniform linear or planar antenna arrays. This works analyses the impact ofthis approximation in the estimated channel capacity and NMSE (normalized mean square error).

Quick access

[PDF]

BibTeX

@article{trindade_muller_klautau_2020,
title={Accuracy Analysis of the Geometrical Approximation of MIMO Channels Using Ray-Tracing},
journal={IEEE Latin-American Conference on Communications – LATINCOM 2020},
author={Trindade, Isabela and Muller, Francisco and Klautau, Aldebaro},
year={2020},
pages={1–5}}

Abstract

In telecommunications networks, users connected toa network node request an amount of resources. This information is of importance for network optimizations problems (e.g., Resource Management), and it is available to the user but not to the network operator. In this work, a machine learning model called Extra Trees infers the actual rate requested by the user only with network performance counters available to the operator. Simulations were used to create instances of the problem and to generate data sets. Results show that the problem is solvable when the network topology is simple, and the network is not facing traffic congestion. However, when the network is performing poorly or has a complicated topology, more advanced techniques are required.

Quick access

[PDF]

BibTeX

@article{dantas_gonçalves_batista_klautau_2020,
title={User Rate Inference From the Network Operator Perspective},
journal={X Conferência Nacional em Comunicações, Redes e Segurança da Informação – ENCOM 2020},
author={Dantas, Diego and Gonçalves, Luan and Batista, Pedro and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

The Fifth-Generation (5G) of mobile networks is differentiated from other generations by the control and management features in which all devices and the network functions can be organized more efficiently. Machine learning (ML) can define an efficient organization to the 5G network and handle the growing complexity of Beyond 5G. Kubeflow is an alternative that uses the Kubernetes cluster to create and manage ML workloads. This article focuses on validating the usability of the Kubeflow project to build Machine Learning systems for 4G/5G networks. We deployed a simple ML workload using Kubeflow, which chooses the best scenario for Virtualized Network Functions (VNF) placement in a Kubernetes cluster of a testbed 4G/5G.

Quick access

[PDF]

BibTeX

@article{tavares_nóvoa_nahum_batista_klautau_2020,
title={Machine Learning Workload in a 4G/5G Testbed using Kubeflow},
journal={X Conferência Nacional em Comunicações, Redes e Segurança da Informação – ENCOM 2020},
author={Tavares, Virgínia and Nóvoa, Lucas and Nahum, Cleverson and Batista, Pedro and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

Nos últimos anos, o particionamento de redes neurais profundas vem ganhando atenção de pesquisadores, pois permite implementar tais redes com uma combinação de processamento local em dispositivos de baixo poder computacional e processamento em nuvem. Neste artigo, é proposto um método de compressão que utiliza normalização de bloco e quantização escalar para um sistema de particionamento de rede neural, a fim de reduzir a taxa de dados necessária para transmissão dos scores da rede através do enlace de comunicação. Para avaliar o desempenho do método, foram realizadas simulações que analisaram a acurácia da rede após a compressão. Os experimentos mostram que ao aplicar normalização em bloco e um quantizador escalar de 6 bits à rede originalmente quantizada em 8 bits, as perdas na acurácia foram de aproximadamente 1%.

Quick access

[PDF]

BibTeX

@article{silva_brito_ramalho_klautau_2020,
title={Compressão dos Sinais de Ativação de Redes Neurais Profundas Particionadas},
journal={X Conferência Nacional em Comunicações, Redes e Segurança da Informação – ENCOM 2020},
author={Silva, Lucas and Brito, Flávio and Ramalho, Leonardo and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

Drones, also known as unmanned aerial vehicles (UAVS), plays a fundamental role in the applications envisioned for 5G and beyond 5G (B5G), with several studies in topics such as UAV-assisted wireless networks, product shipping, traffic monitoring, and surveillance, to name a few. In this context, channel modeling is an essential step in using drones via a wireless communication system. However, the simulations involved in this process use 3D environments to represent the real world; consequently, the complexity of the model and the materials utilized to represent the surfaces can significantly impact the time needed to prepare and run an experiment. This paper compares simulations using different 3D models parameters such as the number of faces, materials, and channel aspects, to investigate their impact on the results.

Quick access

[PDF]

BibTeX

@article{bastos_oliveira_borges_klautau_2020,
title={Effects of Environment Model Complexity in Ray-Tracing Simulation for UAV Channels},
journal={X Conferência Nacional em Comunicações, Redes e Segurança da Informação – ENCOM 2020},
author={Bastos, Felipe and Oliveira, Ailton and Borges, João and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

Fifth-generation (5G) networks are being designed with high levels of virtualization and programmability. Together with a large amount of data, it could benefit from Artificial Intelligence (especially Machine Learning) to improve its cost-efficiency through e.g. automated (intelligent) network configuration. Handling large amounts of data is not a trivial task and Elastic Stack can be useful in such scenarios by allowing real-time data search, logging and analytics. This paper describes an Elastic Stack implementation in a virtualized 4G/5G network testbed for monitoring operational data from the mobile network cluster and network controllers.

Quick access

[PDF]

BibTeX

@article{guerreiro_tavares_nahum_lins_klautau_2020,
title={4G/5G Network Data Collection and Processing using Elastic Stack},
journal={X Conferência Nacional em Comunicações, Redes e Segurança da Informação – ENCOM 2020},
author={Guerreiro, Tiago S. and Tavares, Virgínia and Nahum, Cleverson and Lins, Silvia and Klautau, Aldebaro},
year={2020},
pages={1–2}}

Abstract

In recent years, technology-based studies have surfaced due to the growing interest in the global problem of antibiotic resistance, especially in the bioinformatics field applied to metagenomics, which is able to represent the microorganism and its associated genes in terms of antibiotic resistance. This paper aims to present a novel approach to categorize antibiotic-resistant genes data based on metagenomic databases through an analysis with histogram-based signal processing. The preliminary results show that the approach is effective to identify antibiotic-resistant genes and has a relatively low computational cost.

Quick access

[PDF]

BibTeX

@article{klautau_pinheiro_nascimento_castro_ramos_klautau_2020,
title={Tetra-Nucleotide Histogram-Based Analysis of Metagenomic Data for Investigating Antibiotic-Resistant Bacteria},
journal={XXVII Congresso Brasileiro de Engenharia Biomédica},
author={Klautau, Sofia and Pinheiro, Samya and Nascimento, Arthur and Castro, Pedro and Ramos, Rommel and Klautau, Aldebaro},
year={2020},
pages={1–6}}

Abstract

In this work, we propose a new dataset, the UFPArk, which consists of a selection of video clips based on a surveillance camera’s footage throughout a day. The aforementioned dataset is relevant to areas such as computer vision-based object detection, human behavior detection and Internet of Things (IoT) applications, which gained momentum with recent Deep Learning (DL) breakthroughs. To validate our dataset, we conduct some experiments that illustrate the relevance of this effort and its applicability in academic and commercial environments.

Quick access

[PDF]

BibTeX

@article{nascimento_castro_klautal_golçalves_filho_brito_klautau_2020,
title={Public Dataset of Parking Lot Videos for Computational Vision Applied to Surveillance},
journal={IEEE INTERNATIONAL CONFERENCE ON MACHINE LEARNING AND APPLICATIONS 2020},
author={Nascimento, Ingrid and Castro, Pedro and Klautal, Sofia and Golçalves, Luan and Filho, Carnot and Brito, Flávio and Klautau, Aldebaro},
year={2020},
pages={1–4}}

Abstract

We propose an SNR estimation procedure for systems that transmit frequency-multiplexed analog signals in a channel. It is agnostic to the type of radio signal transmitted, can be performed without increasing the required bandwidth, and without interrupting the transmission of the signals. We simulate the transmission of frequency-multiplexed OFDM signals in an optical channel with intensity modulation of the laser and direct detection, where we show the accuracy of the estimation comparing the estimated SNR to the analytical SNR of the channel.

Quick access

[PDF]

BibTeX

@ARTICLE{9093846,
author={I. {Correa} and B. {Dortschy} and A. {Klautau}},
journal={IEEE Communications Letters},
title={SNR-based Pre-Emphasis for Transmission of Frequency-Multiplexed Radio Signals in Fronthaul},
year={2020},
volume={},
number={},
pages={1-1},}

Abstract

This work investigates a mechanism for alignment of the timing on which spatially distributed and cooperative radio units transmit in radio-frequency (RF) when served over a packet-based fronthaul. It analyzes the problem by considering the imperfect clock synchronization of the radio units and the packet delay variation that fronthaul packets are subject to.

Quick access

[PDF]

BibTeX

@ARTICLE{9088987,
author={I. {Freire} and I. {Almeida} and E. {Medeiros} and M. {Berg} and C. {Lu} and E. {Trojer} and A. {Klautau}},
journal={IEEE Access},
title={Testbed Evaluation of Distributed Radio Timing Alignment Over Ethernet Fronthaul Networks},
year={2020},
volume={8},
number={},
pages={87960-87977}
}

Abstract

Unmanned Aerial Vehicles (UAVs) became very popular in a vast number of applications in recent years, especially drones with computer vision functions enabled by on-board cameras and embedded systems. Many of them apply object detection

Quick access

[PDF]

BibTeX

@article{dantas_braun_forte_brito_silva_lins_linder_klautau_2019,
title={Testbed for Connected Artificial Intelligence using Unmanned Aerial Vehicles and Convolutional Pose Machines},
journal={CBIC 2019: XIV Congresso Brasileiro de Inteligência Computacional},
author={Dantas, Diego and Braun, Carnot and Forte, Kaio and Brito, Flávio and Silva, Andrey and Lins, Silvia and Linder, Neiva and Klautau, Aldebaro},
year={2019},
pages={1–1}
}

Abstract

Community networks deployment is one of several worldwide efforts to reduce the digital divide. Most of these networks rely entirely on IEEE 802.11 (WiFi). In this work,

Quick access

[PDF]

BibTeX

@article{castro_laredo_oliveira_dias_muller_klautau_2019,
title={Uso de Rede de Telefonia Celular Comunitária para Inclusão Social e Digital na Amazônia},
journal={XXXVII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT2019},
author={Castro, Lauro and Laredo, Giovanni and Oliveira, Emerson and Dias, Marcus and Muller, Francisco and Klautau, Aldebaro},
year={2019},
pages={1–1}
}

Abstract

Virtualization is a key feature in Cloud Radio Access Network (C-RAN). It can help to save costs since it allows the use of virtualized base stations instead of physically deployment in different areas. However, the creation and management of

Quick access

[PDF]

BibTeX

@article{novaes_nahum_trindade_cederholm_patra_klautau_2019,
title={Virtualized C-RAN Orchestration with Docker, Kubernetes and OpenAirInterface},
journal={XXXVII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT2019},
author={Novaes, Camila and Nahum, Cleverson and Trindade, Igor and Cederholm, Daniel and Patra, Gyanesh and Klautau, Aldebaro},
year={2019},
pages={1–1}
}

Abstract

Millimeter waves is one of 5G networks strategies to achieve high bit rates. Measurement campaigns with these signals are difficult and require expensive equipment. In order

Quick access

[PDF]

BibTeX

@article{oliveira_dias_trindade_klautau_2019,
title={Ray-Tracing 5G Channels from Scenarios with Mobility Control of Vehicles and Pedestrians},
journal={XXXVII SIMPÓSIO BRASILEIRO DE TELECOMUNICACÕES E PROCESSAMENTO DE SINAIS – SBrT2019},
author={Oliveira, Ailton and Dias, Marcus and Trindade, Isabela and Klautau, Aldebaro},
year={2019},
pages={1–1}
}

Abstract

This article presents the construction of a 4G network and its traffic analysis via network protocols. The main focus is the usage of open-source software to deploy the basic
Quick access

[PDF]

BibTeX

@article{tavares_nóvoa_couto_klautau_muller_2019,
title={Emulação de Rede LTE Usando OpenAirInterface e Análise de Tráfego Via Protocolo de Rede},
journal={XXXVII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS – SBrT2019},
author={Tavares, Virgínia and Nóvoa, Lucas and Couto, Gabriel and Klautau, Aldebaro and Muller, Francisco},
year={2019},
pages={1–1}
}

Abstract

This paper presents a compression scheme devel- oped for the transport of downlink radio signals in packet fronthaul of centralized-radio access networks (C-RAN). The technique is tailored to

Quick access

[PDF]

BibTeX

@article{nahum_ramalho_fortuna_lu_berg_almeida_klautau_2019,
title={Downlink Fronthaul Compression in Frequency Domain using OpenAirInterface},
volume={1},
journal={XXXVII SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS},
author={Nahum, Cleverson and Ramalho, Leonardo and Fortuna, Joary and Lu, Chenguang and Berg, Miguel and Almeida, Igor and Klautau, Aldebaro},
year={2019},
pages={1–1}
}

Abstract

Millimeter wave communication systems can leverage information from sensors to reduce the overhead associated with link configuration. LIDAR (light detection and ranging) is one sensor widely used in autonomous driving for high resolution mapping and

Quick access

[PDF]

BibTeX

@article{klautau_gonzalez-prelcic_heath_2019,
title={LIDAR Data for Deep Learning-Based mmWave Beam-Selection},
journal={IEEE Wireless Communications Letters},
author={Klautau, Aldebaro and Gonzalez-Prelcic, Nuria and Heath, Robert W.},
year={2019},
pages={1–1}
}

Abstract

G.fast is one of the most recent DSL system standardized by ITU. It aims to achieve transmission rates of the order of Gbps over short loops, using bandwidth of 106 MHz or 212 MHz. Owing to its

Quick access

[PDF]

BibTeX

@article{gomes_klautau_pelaes_2019,
title={Modelling and performance evaluation of alien crosstalk mitigation in DMT transmissions},
volume={89},
journal={Digital Signal Processing},
author={Gomes, Diego De Azevedo and Klautau, Aldebaro and Pelaes, Evaldo},
year={2019},
pages={91–103}
}

Abstract

Information-centric networking (ICN) is one of the most promising research topics for the future Internet.
ICN aims at circumventing several issues of current Internet protocol (IP) solutions such as

Quick access

[PDF]

BibTeX

@article{batista_araújo_linder_laraqui_klautau_2019,
title={Testbed for ICN media distribution over LTE radio access networks},
volume={150}, DOI={10.1016/j.comnet.2018.12.013}, journal={Computer Networks},
author={Batista, Pedro and Araújo, Ivanes and Linder, Neiva and Laraqui, Kim and Klautau, Aldebaro},
year={2019},
pages={70–80}
}

Abstract

The synchronization accuracy achieved via the IEEE 1588 Precision Time Protocol (PTP) in packet-based fronthaul networks is substantially impaired by packet delay variation (PDV). Nevertheless, in the particular case of deployment over tree topologies,

Quick access

[PDF]

BibTeX

@article{freire_sousa_bemerguy_klautau_almeida_lu_berg_2018,
title={Analysis of Controlled Packet Departure to Support Ethernet Fronthaul Synchronization via PTP},
url={https://ieeexplore.ieee.org/document/8543068},
journal={2018 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS)},
author={Freire, Igor and Sousa, Ilan and Bemerguy, Pedro and Klautau, Aldebaro and Almeida, Igor and Lu, Chenguang and Berg, Miguel},
year={2018}
}

Abstract

Tools and techniques of high-level languages saw an increase in usage on embedded systems due to the rise in popularity and low cost of high performance development boards with embedded Linux distributions,

Quick access

[PDF]

BibTeX

@article{nakamura_silva_correa_takeda_castro_klautau_2018,
title={Renderização de interface gráffica em sistema embarcado utilizando Node.js e o elemento Canvas},
journal={Computer on The Beach},
author={Nakamura, Andrey K. and Silva, Álan R. B. and Correa, Lucas Q. and Takeda, Marcos Y. and Castro, Adalbery R. and Klautau, Aldebaro},
year={2018}
}

Abstract

Modelos e medidas de canais são essenciais para o desenvolvimento de novas tecnologias de comunicações. Este trabalho adota uma metodologia que combina simulações e medidas no intuito de obter o perfil

Quick access

[PDF]

BibTeX

@article{barbosa_trindade_eras_klautau_barros_araújo_2018,
title={Metodologia para Obtenção de Perfil de Potência e Retardo na Faixa de 10 GHz},
volume={1},
journal={VIII Conferência Nacional em Comunicações, Redes e Segurança da Informação},
author={Barbosa, Brenda and Trindade, Isabela and Eras, Leslye and Klautau, Aldebaro and Barros, Fabricio and Araújo, Jasmine},
year={2018},
pages={29–30}
}

Abstract

Cloud-radio access networks (C-RAN) and carrier aggregation are enabling technologies for high data rate in mobile communications. However, a drawback of C-RAN is

Quick access

[PDF]

BibTeX

@article{takeda_ramalho_lu_berg_klautau_2018,
title={Fronthaul Signal Compression in C-RAN with Carrier Aggregation},
volume={1},
journal={XXXVI SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS},
author={Takeda, Marcos and Ramalho, Leonardo and Lu, Chenguang and Berg, Miguel and Klautau, Aldebaro},
year={2018},
pages={1019–1023}
}

Abstract

The use of higher frequencies and MIMO is important in many 5G use cases. However, the available channel models for millimeter waves (mmWaves) currently demand investigation and

Quick access

[PDF]

BibTeX

@article{trindade_vilas boas_klautau_2018,
title={Evaluation of Simplified Methodology for Obtaining mmWave MIMO Channels from Ray-Tracing Simulations},
volume={1},
journal={XXXVI SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS},
author={Trindade, Isabela and Vilas Boas, Brenda and Klautau, Aldebaro},
year={2018},
pages={959–960}
}

Abstract

The first community celullar network of Brazil with licensed spectrum by ANATEL was inaugurated in 2018. It is located at Campo Verde, Concórdia do Pará municipality, Pará State, Brazil. This paper will present the implementation of this network, describing the services

Quick access

[PDF]

BibTeX

@article{oliveira_dias_vilas boas_klautau,
title={CELCOM: Tecnologias e Experiências Adquiridas em Redes de Telefonia Comunitárias no Brasil},
volume={1},
journal={XXXVI SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS},
author={Oliveira, Emerson and Dias, Marcus and Vilas Boas, Brenda and Klautau, Aldebaro},
pages={905–906},
year={2018}
}

Abstract

Multiple antennas (MIMO) are widely adopted in modern communication systems. Low-cost testbeds that support MIMO transceivers are of interest in both industry and academia. Software-defined radios (SDR) are

Quick access

[PDF]

BibTeX
@article{scherer_paulo_klautau,
title={Avaliação de canal MIMO com ambientes de testes utilizando tecnologia SDR},
volume={1},
journal={XXXVI SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS},
author={Scherer, Bruno and Paulo, Joary and Klautau, Aldebaro},
pages={878–879},
year={2018}
}

Abstract

Some applications and use cases of unmanned aerial vehicle (UAV or drones) in 5G require communication channels with large capacities to transmit, for example, high-resolution videos in real-time. In this case, millimeter waves

Quick access

[PDF]

BibTeX

@article{bastos e bastos_nascimento_klautau_2018,
title={Ambiente de Simulações com Traçado de Raios para mmWave MIMO Aplicado a VANTs},
volume={1},
journal={XXXVI SIMPÓSIO BRASILEIRO DE TELECOMUNICAÇÕES E PROCESSAMENTO DE SINAIS},
author={Bastos e Bastos, Felipe H. and Nascimento, Ingrid and Klautau, Aldebaro},
pages={871–872}}
year={2018}
}

Abstract

Currently, there are about 3.6 billion people in the world without any kind of Internet access. Parallel to this, we have the connectivity as a fundamental part for insertion of the individual in a globalized society. Thus,

Quick access

[PDF]

BibTeX
@article{freitas_neto_muller_leal_abelem_klautau_2019,
title={ Desenvolvimento de redes comunitárias na região amazônica com uso de redes em malha sem fio através da plataforma LibreMesh.},
volume={1},
journal={Computer On The Beach 2019},
author={Freitas, Lorena and Neto, Moacir and Muller, Francisco F. and Leal, Débora and Abelém, Antônio and Klautau, Aldebaro},
year={2019}
}

Abstract

==== MISSING ABSTRACT ====

Quick access

[PDF]

BibTeX

@article{leão_castro_lima_pinto_oliveira junior_klautau_2019,
title={ Projeto CELCOM: Um processo de inclusão digital em comunidades isoladas através de redes comunitárias.},
volume={1},
journal={Computer On The Beach 2019},
author={Leão, Giovanni L. and Castro, Lauro B. and Lima, Marcos and Pinto, Lucas Martins and Oliveira Junior, Emerson S. and Klautau, Aldebaro},
year={2019}
}

Abstract

This letter presents a fronthaul signal compressionscheme based on linear prediction coding adapted to the orthogo-nal frequency division multiplexing signals.

Quick access

[PDF]

BibTeX

@misc{wseas transactions on power systems,
title={Data Warehouse Applied to SCADA Historical Data in Electrical Power Systems},
url={http://www.wseas.org/multimedia/journals/power/2018/a445916-554.php},
journal={WSEAS Transactions on Power Systems},
publisher={World Scientific and Engineering Academy and Society}
}

Abstract

This letter presents a fronthaul signal compression scheme based on linear prediction coding adapted to the orthogo-nal frequency division multiplexing signals.

Quick access

[PDF]

BibTeX

@article{ramalho_freire_lu_berg_klautau_2018,
title={Improved LPC-Based Fronthaul Compression With High Rate Adaptation Resolution},
volume={22},
number={3},
journal={IEEE Communications Letters},
author={Ramalho, Leonardo and Freire, Igor and Lu, Chenguang and Berg, Miguel and Klautau, Aldebaro},
year={2018},
pages={458–461}
}

Abstract

The increasing complexity of configuring cellularnetworks suggests that machine learning (ML) can effectivelyimprove 5G technologies. Deep learning has proven successful in

Quick access

[PDF]

BibTeX

@article{klautau_batista_gonzalez-prelcic_wang_heath_2018,
title={5G MIMO Data for Machine Learning: Application to Beam-Selection Using Deep Learning},
journal={2018 Information Theory and Applications Workshop (ITA)},
author={Klautau, Aldebaro and Batista, Pedro and Gonzalez-Prelcic, Nuria and Wang, Yuyang and Heath, Robert W.},
year={2018}}
}

Abstract

Modelos e medidas de canais são essenciais para o desenvolvimento de novas tecnologias de comunicações. Este trabalho adota uma metodologia que combina simulações e medidas no intuito de obter o perfil de Potência e Retardo (PPR) de interesse para a

Quick access

[PDF]

BibTeX

@article{barbosa_trindade_eras_klautau_barros_araújo_2018,
title={Metodologia para Obtenção de Perfil de Potência e Retardo na Faixa de 10 Ghz.},
journal={ENCOM 2018},
author={Barbosa, Brenda and Trindade, Isabela and Eras, Leslye and Klautau, Aldebaro and Barros, Fabrício and Araújo, Jasmine P.L},
year={2018},
pages={1–10}
}

Abstract

Algumas aplicações e casos de uso de veı́culos aéreos não tripulados (VANT ou drones) em 5G requerem canais de comunicação com grandes capacidades de transmissão,por exemplo, vı́deos de alta resolução em tempo real. Neste caso, as ondas milimétricas (mmWaves) são

Quick access

[PDF]

BibTeX

@article{barros_nascimento_klautau_2018,
title={Ambiente de Simulações com Traçado de Raios para mmWave MIMO Aplicado.},
journal={SBRT 2018},
author={Barros, Felipe H.B.E. and Nascimento, Ingrid and Klautau, Aldebaro},
year={2018},
pages={871–872}
}

Abstract

Múltiplas antenas são amplamente utilizadas nos sistemas de comunicação (MIMO). Testbeds de baixo custo que deem suporte à comunicação com MIMO são de interesse tanto para

Quick access

[PDF]

BibTeX

@article{scherer_fortuna_klautau_2018,
title={Avaliação de canal MIMO com ambientes de testes utilizando tecnologia SDR.},
journal={SBRT 2018},
author={Scherer, Bruno and Fortuna, Joary and Klautau, Aldebaro},
year={2018},
pages={878–879}
}

Abstract

Cloud-radio access networks (C-RAN) and carrier aggregation are enabling technologies for high data rate in mobile communications. However, a drawback of C-RAN is the high volume of data that must be

Quick access

[PDF]

BibTeX

@article{takeda_ramalho_lu_berg_klautau_2018,
title={Fronthaul Signal Compression in C-RAN with Carrier Aggregation.},
journal={SBRT 2018},
author={Takeda, Marcos Y. and Ramalho, Leonardo and Lu, Chenguang and Berg, Miguel and Klautau, Aldebaro},
year={2018},
pages={1019–1023}
}

Abstract

This work describes the implementation of a satellite tracking technique in a real antenna control system. The technique uses least squares estimation to search for the best antenna pointing position to

Quick access

[PDF]

BibTeX

@article{sarmento_nakamura_silva filho_correa_takeda_castro_klautau_2018,
title={Development and Evaluation of Least Square Satellite Tracking in Real Antenna Control System.},
journal={SBRT 2018},
author={Sarmento, Thiago L. and Nakamura, Andrey K. and Silva FIlho, Iteli N. and Correa, Lucas and Takeda, Marcos Y. and Castro, Adalbery and Klautau, Aldebaro}, year={2018},
pages={1084–1087}
}

Abstract

The automatic classification (or identification) of modulation schemes and radio access technologies (RAT) find several applications in military and cognitive radio systems. As in other domains, deep learning has been applied to

Quick access

[PDF]

BibTeX

@inproceedings{inproceedings,
author = {Nascimento, Ingrid and Mendes, Flavio and Dias, Marcus and Silva, Andrey and Klautau, Aldebaro},
year = {2018},
month = {09},
title = {Deep Learning in RAT and Modulation Classification with a New Radio Signals Dataset}
}vc_column_text]

Abstract

In this project, we leverage offline/online learning approaches to recommend beams and predict beam power for mmWave vehicle-to-infrastructure (V2I) communication, based on vehicles’ situational awareness.

Quick access

[PDF]

BibTeX

@article{wang_klautau_ribero_narasimha_heath_2018,
title={MmWave Vehicular Beam Training with Situational Awareness by Machine Learning},
journal={2018 IEEE Globecom Workshops (GC Wkshps)},
author={Wang, Yuyang and Klautau, Aldebaro and Ribero, Monica and Narasimha, Murali and Heath, Robert W.},
year={2018}
}

Abstract

The synchronization accuracy achieved via the IEEE 1588 Precision Time Protocol (PTP) in packet-based fronthaul networks is substantially impaired by packet delay variation (PDV). Nevertheless, in the particular case of deployment over tree topologies, it is known that PDV can be avoided by controlling the departure of PTP packets such that they experience close to constant delays over the fronthaul.

Quick access

[PDF]

BibTeX

@inproceedings{freire2018analysis,
title={Analysis of Controlled Packet Departure to Support Ethernet Fronthaul Synchronization via PTP},
author={Freire, Igor and Sousa, Ilan and Bemerguy, Pedro and Klautau, Aldebaro and Almeida, Igor and Lu, Chenguang and Berg, Miguel},
booktitle={2018 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control, and Communication (ISPCS)},
pages={1–6},
year={2018},
organization={IEEE}
}

Abstract

The noise present in embedded analog-to-digital converter (ADC) of microcontrollers (MCUs) and other System-on-chips (SoCs) is a limiting factor that can impede their use in some application. This noise can be caused due to the proximity between ADCs and digital circuits whose switching couples to the analog signals and

Quick access

[PDF]

BibTeX

@inproceedings{ferreira2017noise,
title={A noise-cancelling technique for data acquisition systems: A case study on embedded ADCs},
author={Ferreira, Jamelly and Trindade, Isabela and Ramalho, Leonardo and Sousa, Ilan and Klautau, Aldebaro},
booktitle={2017 2nd International Symposium on Instrumentation Systems, Circuits and Transducers (INSCIT)},
pages={1–6},
organization={IEEE}
}

Abstract

Current video streaming demands are motivating research on cost-efficient solutions for distributing such large traffic amount. Information-Centric Networking (ICN) is a relevant new paradigm that can inherently benefit from multipath transport. This work contributes specifically evaluating the impact of multipath transport in ICN

Quick access

[PDF]

BibTeX

@misc{impact of multipath in mobile backhaul savings for icn …,
url={https://www.researchgate.net/publication/331357699_Impact_of_Multipath_in_Mobile_Backhaul_Savings_for_ICN_Architectures_An_Evaluation_Using_ndnSIM}
}

Abstract

Alien crosstalk is one of the major impairments forcopper-based transmissions. This letter outlines a method for mitigating alien crosstalk for digital subscriber line downstream transmissions impaired by multiple interference sources. The method requires a

Quick access

[PDF]

BibTeX

@article{gomes_medeiros_klautau_pelaes_2017,
title={Mitigation of Alien Crosstalk for Downstream DSL Impaired by Multiple Interferers},
volume={21},
number={11},
journal={IEEE Communications Letters},
author={Gomes, Diego and Medeiros, Eduardo and Klautau, Aldebaro and Pelaes, Evaldo},
year={2017},
pages={2380–2383}
}

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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-

Quick access

[PDF]

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

Quick access

[PDF]

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

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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,

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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-

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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,

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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”

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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)

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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.

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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.

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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-

Quick access

[PDF]

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,

Quick access

[PDF]

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

Quick access

[PDF]

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)

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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,

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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.

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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.

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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,

Quick access

[PDF]

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,

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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”

Quick access

[PDF]

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

Quick access

[PDF]

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

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)

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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

Quick access

[PDF]

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}
}