Dissertações em Engenharia Elétrica (Mestrado) - PPGEE/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2316

O Mestrado Acadêmico inicou-se em 1986 e pertence ao Programa de Pós-Graduação em Engenharia Elétrica (PPGEE) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).

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Agora exibindo 1 - 4 de 4

Acesso aberto (Open Access)
Análises de atividades oscilatórias de EEG durante treinamento cognitivo e análise espectral de Holo-Hilbert
(Universidade Federal do Pará, 2022-07-19) SOUZA, Suzana Cescon de; GOMES, Bruno Duarte; http://lattes.cnpq.br/4932238030330851; PEREIRA JÚNIOR, Antonio; http://lattes.cnpq.br/3239362677711162
In this work we developed a protocol for the analysis of a cognitive training (TC), in order to raise the performance in bulldozer operators of Vale S.A. This research took part of the POAD (High performance operators' program) Innovation Project of the Vale Technological Institute ITV). The protocols of the TC were based in Neurofeedback (NFB), in order to develop the ability to self-regulate cerebral frequencies, based on electroencephalogram (EEG) analysis. In this research, the Holo-Hilbert Spectral Analysis (HHSA) for the study of amplitude modulation (AM) band frequency (FM) of the rhythms that compose the cerebral frequencies. The HHSA was based on empirical mode decomposition (EMD) in two layers. First the EEG signal has been decomposed in a series of intrinsic mode function in modulated frequency (IMFs) and then every IMF modulated in frequency have been decomposed in a sel of IMFs modulated in amplitude. thus. the present work explores the eflicicney of an TC bas s on modulated frequency and amplitude variations in EEG data obtained via NFB. The results show statistical relevance for the group-who went through the TC showing the effects of the application of TC, Moreover validate the efficacy of HHSA in the extraction of informative characteristics from the signals
Acesso aberto (Open Access)
FPGA-based testbed for fronthaul signal compression: implementation and validation
(Universidade Federal do Pará, 2017-03-24) FORTUNA, Joary Paulo Wanzeller; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
In recent years the world has seen an increasing demand for mobile services with high capacity and low cost. Such requirements forced the radio access technologies to be rethought. Among the different architectures proposed in literature, one that has got a lot of attention was the Centralized Radio Access Network (C-RAN). This strategy proposes to share the network resources through the centralization of the base-band processing and, as a result, reduce the network cost. Even though the centralization can bring several benefits, it also increases the distance between the point where the signal is captured and the point where it is processed. The link connecting both points is called fronthaul. In this scenario, the existing fronthaul technologies do not fit in the flexibility and cost requisites expected for the next generation mobile network, mainly due to the usage of dedicated optical links. One solution to these problems is the usage of Ethernet to transport fronthaul data, due to its ubiquitous presence, flexibility and low cost. In this work, a testbed for fronthaul based on Ethernet is presented, along with the implementation details and validation results. Also motivated by the Ethernet’s bandwidth limitation, this work presents the VHDL implementation of a compression technique for LTE signals, evaluated in real transport conditions with the testbed. The obtained results indicate that it is possible to utilize the Ethernet network infrastructure for fronthaul transport. Although, it is necessary to reduce the requirements of Fronthaul stream through, for example, the application of signal compression techniques and synchronization methods.
Acesso aberto (Open Access)
Um protótipo para desenvolvimento e aplicação de estratégias de otimização em sistemas xDSL práticos
(Universidade Federal do Pará, 2010-04-19) MEDEIROS, Eduardo Lins de; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
This work describes the development of a prototype for the application of optimization strategies for practical xDSL systems. The prototype described here is made of software components and an experimental setup, capable of generating IP tra c and noise signals, in order to evaluate the performance of a complete DSL network in a controlled environment, with commercial unmodi ed hardware. The results obtained with the prototype as well as its applications for optimization of practical xDSL systems are presented.
Acesso aberto (Open Access)
Techniques of downstream rate balancing for vectored digital subscriber line systems: case study of the ITU G.9700 standard
(Universidade Federal do Pará, 2015-03-10) COUTINHO FILHO, Claudio de Castro; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
As the DSL (Digital Subscriber Line) technology reaches its physical bandwidth limit and the Fiber-to-the-Home (FTTH) model becomes a potential substitute, new techniques and standards are developed to cope with the requirements from the Internet access industry. In this context, the newly agreed G.9700 (G.fast) standard, from the International Telecommunication Union (ITU), brings to the copper plant a renewal of its lifespan with the use of techniques such as Vectoring. Although Vectoring is a powerful tool for DSL to become a competitive technology for optical fiber, it must deal with the problem that subscribers still may get differing rates at their CPEs (Customer Premises Equipment), caused mainly by physical aspects of the channel. With that in mind, this work proposes methods of balancing the achievable rates delivered to user lines at Downstream. This is done by using different column sortings of the channel matrix, in scenarios that utilize the Tomlinson-Harashima Precoder (THP) up to 200 MHz. Simulations using each rate balancing method on six measured cables are made in order to show each method’s progress. These simulations are extended to the Near-Far Scenario, which tries to resemble the situations where some lines have greater length than others, that is, differing distances between the CPE and the DSLAM (Digital Subscriber Line Access Multiplexer). The proposed methods yielded promising balancing result, with reductions of up to 95.79% of the standard deviation for the Swisscom I51 cable, when comparing results of a genetic algorithm method with those of the THP.

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