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).

Navegar

Agora exibindo 1 - 20 de 108

Acesso aberto (Open Access)
Abordagem de leitura de texto em imagens provenientes de redes sociais para ganho em disponibilidade de dados
(Universidade Federal do Pará, 2017-10-19) FERREIRA NETO, Luiz Cortinhas; SANTANA, Ádamo Lima de; http://lattes.cnpq.br/4073088744952858
This work aims to propose a methodological adaptation in the process of social network analisys, based on the inclusion of text extracted from images that are obtained from the social networks themselves. Highly important for market intelligence, product analysis, CRM and SCRM processes, since these are market trends used by large companies, thus, promotes financial and research incentives. The adaptation proposed in here has its importance based on data availability, which has become increasingly restricted, thanks to the use of APIs, interfaces of data access management where, in several different ways, each social network limits the data query, either by type of data, quantity or collected window. This research intends to prove, through case studies, that there is relevant information gain to sentiment analyses process when textual data derived from images are used.
Acesso aberto (Open Access)
Abordagem probabilística para caracterização do sistema de marcação de sequenciamento multiplex na plataforma ABI SOLID
(Universidade Federal do Pará, 2011-07-01) LOBATO, Fábio Manoel França; SANTANA, Ádamo Lima de; http://lattes.cnpq.br/4073088744952858
The next generation sequencers such as Illumina and SOLiD platforms generate a large amount of data, commonly above 10 Gigabytes of text files. Particularly, the SOLiD platform allows the sequencing of multiple samples in a single run (called multiplex run) through a marking system called Barcode. This feature requires a computational process for separation of data per sample, therefore, the sequencer provides a mixture of all samples in a single output. This process must be secure to avoid any harm that may scramble further analysis. In this context, this dissertation proposes development of a probabilistic model capable of characterizing the marking system used in multiplex sequencing. The results corroborate the adequacy of the model obtained, which allows, among other things, identify faults in some step in the sequencing process, adapt and develop new protocols for sample preparation, and assign a grade to the reliability of data generated and guide a filtering process that respects the characteristics of each sequence, without discarding sequences useful in an arbitrary manner.
Acesso aberto (Open Access)
Ações de eficiência energética em navios: estudo de caso e um navio patrulha da Marinha do Brasil
(Universidade Federal do Pará, 2016-08-26) AQUINO, Suzane Cruz de; MORAES, Hito Braga de; http://lattes.cnpq.br/5044859479302394; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
Due to growing concern about the environment, the IMO (International Maritime Organization), through MARPOL (International Convention for the Prevention of Pollution from Ships), has developed the first mandatory regulation of the area about the energy efficiency of ships aiming the reduction of greenhouse gases emissions and costs related to energy consumption. This dissertation proposes a methodology of energy efficiency measures in a patrol ship of the Navy of Brazil. The analyzed ship, the P-49 or Guarujá, is a 19 years old vessel just as almost all its equipments. The Guarujá is electrically a isolated propulsion system from the power generation, then the target of this research were those systems with the highest electricity demand: the lighting system, cooling, electric power generation, saving and cold storages. However, the information available above those systems have proven scarce, thus it was exploited only the bulbs and some compressors and fan motors. The actions proposed to equipment available verification were 1. the exchange of the reference case bulbs with LED lamps; and 2. replacing the engines with similar specimens of higher yield. They were analyzed financially and environmentally by RETScreen software, an important tool for energy efficiency and renewable sources studies developed by the Government of Canada; with the aid of PROCEL simulator, BD Motor, promoting greater focus on the engines due to its complexity and significance in the optimal functioning of the ship's systems. The actions proved viable, with the total turnaround time of two years, reducing emissions by 164 tCO2 in 20 years and saving about R$ 352,974.80 at the end of the project time, thus justifying their implementation.
Acesso aberto (Open Access)
Acoplamento de modos guiados em cabos de pares trançados utilizando antenas com simetria radial no cenário terabit DSL
(Universidade Federal do Pará, 2020-03-26) SOUSA, Brenda Penedo Tavares de; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
The development of data transmission standards and access technologies has always been linked to the need to supply high data rates. Thus, technologies already implemented, such as the DSL (Digital Subscriber Line) system that uses twisted pairs for transmission, have been adjusting to support this growing data demand. In DSL systems, the twisted pairs are used as a transmission line, using the transverse electromagnetic mode (TEM). However, the physical limitations of the twisted pair as a transmission line prevent the system from achieving higher rates, needed to support fifth generation (5G) applications. Recently, it was proposed to use other transmission modes in the twisted pair, the higher order guided modes, as an alternative for this structure to be able to support transmission rates of the order of Terabits per second, having been termed as the Terabit DSL technology (TDSL). However, one of the challenges for this implementation is the coupling of the guided modes in the twisted pair, since they are not widely explored in the context of the propagation of higher-order guided modes, as simpler waveguides, such as Sommerfeld and Goubau. In this scenario, this dissertation aims to evaluate the coupling of the radiated signal between an antenna with radial propagation and the twisted pair cable, analyzing the electromagnetic behavior of structures. Considering that the twisted pair cable does not have a closed analytical model for the behavior of higher order modes, which propagate along these structures, all the results were obtained from numerical simulations in the software HFSS (High Frequency Structure Simulator).These results are in terms of the scattering parameter of the antenna and the electromagnetic field in the cable, making it possible to evaluate the coupling efficiency, the signal guidance and to predict the transmission rate available to users. The results obtained showed that the coupling between the antenna and the unshielded twisted pair cable reached levels of up to 83.83 % at frequencies of 0.15 THz, demonstrating a high coupling efficiency when compared to simpler scenarios in the literature, reaching levels on average 67 %. It was found that the use of these cables for data transmission is effective, managing to deliver rates of up to 1.737 Tbps in cables of up to 10 meters, while the rate forecasts for the TDSL scenario that consider the 100 % coupling reach levels of 2.013 Tbps.
Acesso aberto (Open Access)
Alocação de dois níveis para uma arquitetura h-cran baseada em offloading
(Universidade Federal do Pará, 2019-01-24) GONÇALVES, Mariane de Paula da Silva; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
The accelerated data and apps growth represents significant challenges to the next generation of mobile networks. Amongst them, it is highlighted the necessity for a co-existence of new and old patterns during the transition of architectures. Thus, this paper has investigated solutions for offloading into a hybrid architecture, also known as H-CRAN (Heterogeneous Cloud Radio Access Network Architecture), that centralizes processing and searches a better use of the network resources. The strategy of optimization was analyzed through the evolutive algorithm PSO (Particle Swarm Optimization), in order to find a suboptimal solution to the allocation of two levels (TLA) in the H-CRAN architecture and another one based on FIFO (First In, First Out), for benchmarking purposes. SNR (Noise Interference Signal) average, Maximum Bit Rate, the number of users with or without connections and number of connections in RRHs and macro were used as performance measurements. Through the results, it was noticed an improvement of approximately 60% in the Maximum Bit Rate when compared to the traditional approach, enabling a better service to the users.
Acesso aberto (Open Access)
Análise comparativa de nanoantenas plasmônicas no modo de recepção para a aplicação em nanocircuito óptico.
(Universidade Federal do Pará, 2020-01-30) LOPES, Patrik Coelho; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647; https://orcid.org/0000-0003-4393-3217
In this work, a theoretical study is made for different cases of optical nanoantennas. Numerical analyzes are performed using the Finite Element Method (FEM). The first part of the analysis will be done with the isolated nanoantennas considered: dipole,dipole-loop, loop and rod-loop. Initially it is made for the transmission mode to obtain important parameters for the study of nanoantennas, such as input impedance, reflection coefficient, radiation efficiency and gain diagram. Later in reception mode, excited by a plane wave linearly polarized, varying the direction of polarization. Where the power received by charge versus frequency and the near-field electric are investigated for antennas. The results show that the case of the dipole-loop nanoantenna is the most efficient (reaching up to and er = 81.25%) in addition to a better reception band. The second part is presented the application of an optical nanocircuit, composed of the receiving loop connected to a bifilar Optical Transmission Line (OTL) with a dipole at the line end. Also investigated are the near-field and the received power for the nanocircuits analyzed separately, with a load at the terminal of the streaming. Finally, the excitation of the nanocircuit is done through an opening probe modeled by a gaussian beam, focused on the receiving loop, transferring energy to the emitting dipole, with a standing wave pattern, the electromagnetic coupling of the nanocircuit turns with the Gaussian beam, showed better results (with a maximum reached of PZC = −103 dBm) compared to the plane wave (with value maximum of PZC = −125 dBm), with the power received at the load of ZC = 50Ω.
Acesso aberto (Open Access)
Análise da qualidade de energia em sistemas de distribuição através de medição e fluxo de carga harmônico trifásico
(Universidade Federal do Pará, 2005-02-10) BRANCHE, Marcos Nascimento; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813; TOSTES, Maria Emília de Lima; http://lattes.cnpq.br/4197618044519148
This work presents an analysis about the power quality, carried out in a real electrical energy distribution grid, considering different customers groups, located in the low voltage grid. The study was made in two steps. The first one through measurements registered in the transformers of the distribution grid supplied by CEA – Amapá’s Electricity Company, previously classified in groups as: commercial group, residential group and home-and-commercial group, identifying and characterizing the generators sources of harmonics generation in the system, making possible, this way, an analysis of the harmonic injection level in the distribution grid as well as the impacts these distribution sources of harmonic generation can provoke in the power quality offered by the CEA utility. The last stage of the study presents the use of a threephase harmonic load flow, where, considering the harmonic profile found out through the measurements carried out, a global evaluation of the system is provided.
Acesso aberto (Open Access)
Análise de canal para frequência de 3,5 GHz em aeroporto
(Universidade Federal do Pará, 2022-01-28) MACEDO, Alex Sanches; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609; http://lattes.cnpq.br/9758585938727609
With the constant evolution of technology and communication systems, the increase in data exchange, speed and reliability regarding access to the mobile network has reinforced. Several causes such as spectral deficiency, difficulties in signal coverage, problems with antennas and radio link, are obstacles to be worked on and improved in order to provide services with higher quality within a mobile communication network infrastructure. To meet the vertiginous increase in the consumption of users and equipment connected to the mobile network, several works and researches are being proposed and developed. In Brazil, the arrival of fifth generation technology (5G) is expected from 2021, which will use the frequency band of 3.5 GHz. 5G promises fast connectivity with more users covering services and applications that demand high data rates over a wide coverage area. In particular, on this frequency that represents a sub-6 GHz band to be used for 5G in Brazil. As for the behavior of the channel, the characterization of this channel is of important relevance. Thus, in this dissertation, the study on channel analysis for the frequency of 3.5 GHz in a large indoor environment was motivated, this scenario is in a lobby of the International Airport Val de Cans, in Belém do Pará. measurements were performed for Line-Of-Sight (LOS) and through channel probing the dispersion parameters of the small-scale channel are extracted. These parameters are the average RMS delay and average RMS spread, the channel coherence band and the power profile and delays were also verified. Understanding large-scale signal propagation is important for designing mobile radio systems. The signal was also investigated through the Floating-Intercept (FI), Close-In (CI) models and their variations are applied and analyzed to evaluate the path loss for co-polarization (V-V and H-H) and cross-polarization (V-H and H-V ). It can be inferred that the methodology applied on a large scale proved to be adequate with the data and, when compared to other types of environments and other frequencies found in the literature.
Acesso aberto (Open Access)
Análise de correlação de focos de queimadas com variáveis climáticas no município de Marabá
(Universidade Federal do Pará, 2016-03-10) ARANHA, Priscila Siqueira; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
The Amazon is composed of a wide variety of ecosystems and forms of occupation, taking a wide variety of settings, including spatial, social, economic, agronomic, which vary from region to region. From this perception of the Amazon region, this work presents an investigative study scenarios and their correlations, in order to quantify and qualify the strength of relationships and dependencies between the different variables involved, such as meteorological factors (relative humidity, rainfall, speed wind and temperature) and the number of fire outbreaks, in order to enable the analysis of the reasons that influence the environmental degradation of the study area. In order to validate the proposed methodology, we conducted a study in the city of Maraba area of settlement projects, whose focus is to analyze the correlation between climate variables and fire outbreaks in the region, using three study scenarios. Therefore, we use some statistical parameters, the Pearson correlation and Bayesian networks in order to establish the degree of dependency between the different variables of interest. From such studies, it is possible to make a set of inferences about the problem under study and possible alternatives, which more balance scenarios for the benefit of environmental sustainability.
Acesso aberto (Open Access)
Análise de desempenho de códigos concatenados em canais AWGN e com multipercursos: uma abordagem baseada em transmissão de vídeo em 4K codificado em H.264
(Universidade Federal do Pará, 2017-03-10) COSTA, Thiago de Araújo; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
In the process of digital transmission the communication channel inserts a series of imperfections in the information transmitted. In order to improve the quality of digital multimedia broadcasting, a number of technologies, such as DVB-T (Digital Video Broadcasting Terrestrial) and DVB-T2 (Digital Video Broadcasting Terrestrial-2nd Generation) employing channel coding techniques have been developed. Within this context, channel coding techniques are of great importance because they minimize the probability of error during the transmission of the information. Thus it becomes important to evaluate the performance of the channel encoders. This dissertation performs a comparative analysis of the concatenated RS-CONV and BCH-LDPC encoders (They are implemented in Digital TV) over the AWGN and Rayleigh channels; Both in terms of BER, as well as in terms of video quality through the PSNR and SSIM metrics. In simulations over the AWGN channel the concatenated pair BCH-LDPC obtained the best performance in conjunction with the QPSK modulation, reaching the value of BER equal 0 when 𝐸𝑏/𝑁0 equals 1 dB. In the Rayleigh channel simulations, the BCH-LDPC association with the QPSK modulation presented the best results, reaching the BER equal 0 from 𝐸𝑏/𝑁0 equal 3 dB. In the video quality evaluation the BCHLDPC concatenated pair showed a superiority over the RS-CONV in the studied channels, in such a way that it conferred an increase (gain) on the mean of the PSNR in relation to the RS-CONV, that for the channel AWGN was approximately 2.2 dB, 6.4 dB and 6.7 dB, respectively for QPSK, 16-QAM and 64-QAM. In the Rayleigh channel the values were approximately 3.9 dB, 4.2 dB and 1.6 dB, respectively for QPSK, 16-QAM and 64-QAM. To confirm the results, another analysis is performed for a given band of the video, showing an increase in the mean of the results of the BCH-LDPC in relation to the RS-CONV, which for the AWGN channel was 15.8 dB for QPSK; 22.23 dB for 16-QAM and 14.3 dB for 64-QAM. While for Rayleigh channel the increase was 16.8 dB, 10.3 dB and 1.4 db, respectively, for QPSK, 16-QAM and 64-QAM.
Acesso aberto (Open Access)
Análise de Desempenho de Meta-heurísticas Aplicadas ao Problema de Restauração de Redes de Distribuição.
(Universidade Federal do Pará, 2020-02-20) BATISTA, Vítor dos Santos; BEZERRA, Ubiratan Holanda; http://lattes.cnpq.br/6542769654042813
In the last years, several meta-heuristics have been used to solve the problem of restoring distribution systems efficiently. Among them, the Multiobjective Evolutionary Algorithm with Node-depth encoding (MEAN) stands out, which together with Node-Depth Encoding (NDE) makes a great advance in the field. All this because the NDE makes changes on the topology of the distribution system without losing radiality and reestablishing the power supply for all disconnected loads after the fault. Due to the lack of exploration of other meta-heuristics that use NDE as a data structure, this work aims to evaluate a performance analysis comparing MEAN with three other meta-heuristics, Tabu Search, Artificial Bee Colony and Evolutionary Strategies. The analysis was performed in three distribution systems the84-bus, 119-bus and 135-bus.s
Acesso aberto (Open Access)
Análise de desempenho de redes de acesso G.mgfast e fronthaul 5G baseado em cabos coaxiais
(Universidade Federal do Pará, 2019-05-27) FREITAS, Marx Miguel Miranda de; NUNES, Diogo Lobato Acatauassú; http://lattes.cnpq.br/1972007941497086; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
This work explores two possibilities of harnessing mature cabling technologies used in broadband networks of 4th generation systems in emerging next generation applications. Specifically, two proposals for using the cabling structure of Hybrid Fiber Coax and SAT TV (Satellite Television) systems are evaluated. The first one, as support in 5G network analog transport networks (fronthaul). The second evaluates the use of coaxial cables in access networks G.mgfast (Multi Gigabit G.fast). In the firs one, It is shown the relationships between the data rates and the number of antennas reached by the coaxial cable RG06, under a fixed power level and a target signal noise condition, considering different distances and two configurations of radio signals. It is shown that in the 5G analogue fronthaul analyzed, rates higher than 40 Gbps can be obtained in a RG06 coaxial cable, giving support to 140 antennas, meeting 3GPP transmission criteria. The second solution proposes a process to reduce power consumption in the network, by adapting the transmission power in the coaxial network, with higher bit load in the initial frequencies of the spectrum. Links with RG59, RG06 and RG11 coaxial cables are analyzed, considering rates ranging from 5 Gbps to 10 Gbps and two types of bit loading algorithms. It is shown that with these procedures the power saving obtained in single link with 100 m coaxial cable can be used to power another 28 cables of 50 m. On the other hand, it is shown that the power reduction is not relevant, from the point of view of redistribution, in cables whose length is less than or equal to 25 m.
Acesso aberto (Open Access)
Análise de desempenho de um sistema fotovoltaico domiciliar de pequeno porte operando com diferentes equipamentos
(Universidade Federal do Pará, 2015-02-23) MAIA, Keila Cristina dos Santos; PINHO, João Tavares; http://lattes.cnpq.br/0847897516772421; MACÊDO, Wilson Negrão; http://lattes.cnpq.br/3386249951714088
This work presents the operational analysis of the operation of a 180 Wp solar home system designed to supply small loads. The solar home system is installed at the laboratory testing area of the “Grupo de Estudos e Desenvolvimento de Alternativas Energéticas” (GEDAE), in order to simulate its operation as electricity supply for a typical riparian residence of the Amazon. For this, it was simulated the use of loads that are frequently used in these homes (TV and lamps) at predefined times. Besides the description of the system components, the mechanisms for monitor its operation and to analyze the data obtained about the behavior of the system operating with different technologies of inverters (sine, square and modified square output waveforms), charge controllers and deep cycle batteries are also presented.
Acesso aberto (Open Access)
Análise de ressonâncias eletromagnéticas em estrutura periódica de discos de grafeno magnetizadosd na faixa de terahertz
(Universidade Federal do Pará, 2023-02-27) SILVA, Amanda Evangelista da; OLIVEIRA, Cristiano Braga de; http://lattes.cnpq.br/2012907724305086; DMITRIEV, Victor Alexandrovich; http://lattes.cnpq.br/3139536479960191
Since its isolation in 2004, graphene has shown to be a promising material, as it allows strong interaction of charge carriers with terahertz (THz) radiation. This extensive interaction with light is due to the excitation of surface plasmon polaritons (SPPs) thus providing several applications in the areas of THz photonics. In the presence of an external magnetic field, the cyclotron resonance dominates in the THz spectra. In this work we analyze several resonance modes (dipole, quadrupole, hexapole and modes with azimuthal symmetry) that can exist in the graphene disk in an arrangement with periodic square unit cells. We calculated the resonances with magnetization by an external DC magnetic field ranging up to 3T and compared them with the case of the same structure without magnetization where it was observed that the presence of the magnetic field results in the splitting of some resonant modes. The resonant characteristics are numerically obtained using the COMSOL Multiphysics software in two distinct and complementary studies: the eigenfrequency calculation regime referring to the natural modes of resonance and the plane wave excitation with normal incidence. Floquet boundary conditions on the four sides of the unit cells are used to simulate the in-plane periodic structure of graphene. The unit cell side (i.e. the period of the matrix) used in the numerical calculation is A = 9µm, the radius of the graphene disk is D = 3µm. The problem of excitation of some modes is discussed from the point of view of the circular symmetry that, to generate the resonance peaks in this regime, had to be broken through a subtle cut in the shape of a rectangular slit of size Lx = 10nm by Ly = 550nm starting axially from the edge. The disk is modeled as a two-dimensional element, and this provides a good approximation of the atomic thickness of a single layer of this material. Conductivity is modeled by the semi-classical Drude model. The discussion of resonator properties is fulfilled in terms of graphene currents and electromagnetic fields outside graphene. Potential applications of the obtained results are Faraday and Kerr rotators, controllable filters and absorbers for THz photonic circuits
Acesso aberto (Open Access)
Análise de sensores de descargas atmosféricas: protótipo de um detector de raios com estimativa de densidade de raios para região amazônica utilizando PSoC
(Universidade Federal do Pará, 2014-02-24) LEAL, Adônis Ferreira Raiol; ROCHA, Brigida Ramati Pereira da; http://lattes.cnpq.br/9943372249006341
This work proposes the design of a prototype for detect lightning, which will, count the number of lightning detected, calculate the density of lightning to the area of operation of the sensor and to estimate the peak of the variation of the electric field for the instant occurrence of discharge. A study of atmospheric electricity, types of lightning, emission of electromagnetic waves during the occurrence of the lightning , types of electromagnetic sensors and lightning detection networks gave subsidy to the design of the prototype . The prototype consists of two antennas, one loop antenna and a flat plate antenna , and electronic circuits , these electronic circuits are implemented mostly in PSoC device ( Programmable System -on - Chip ) , which is a relatively new technology that works with analog and digital signals and also has a CPU to perform the processing of these signals . The validation of the data obtained and estimated coverage area of the sensor, were based on data from STARNET network (sferics Timing And Ranging NETwork). The prototype was designed to be low cost, have a simple and straightforward interface and can be installed in the Amazon region.
Acesso aberto (Open Access)
Análise de um sensor baseado em ressonância de superfície de plasma acoplado a um arranjo periódico de nanopartículas metálicas
(Universidade Federal do Pará, 2016-07-05) COSTA, Jefferson Souza; COSTA, Karlo Queiroz da; http://lattes.cnpq.br/7932708321834647
SPR sensors are photonic devices based on surface plasma resonance (SPR), which consists of longitudinal collective oscillation of free electron gas at the interface between a metal and a dielectric. Due to its surface stimuli sensitive response, the use of SPR sensors has been reported for various applications. In this paper, we evaluate an SPR sensor coupled to the periodic array of metal (gold) nanoparticles, which can represent the surface immobilization of metal nanopollutants generated, for example, from the nanocomposites manufacturing process. The the SPR sensor multilayer structure is compounded by a prism, a gold thin film and a SiO2 layer. The sensor response to variations in the nanoparticles array is theoretically analyzed by an analytical model based on the effective permittivity of Maxwell Garnett and the generalized reflection coefficient for planar multilayer structure. The analytical model is validated by comparison with experimental and numerical results, showing great accuracy for a given range of values of the periodic array parameters. The evaluation the allowed wave modes of the sensor structure and the multi-layer structure optimization, for the detection and characterization of static parameters of metal nanoparticles, are the main objectives of the analysis developed in this work.
Acesso aberto (Open Access)
Análise dinâmica da condição de runaway em reguladores de tensão devido á presença de geração fotovoltaica nas redes de distribuição
(Universidade Federal do Pará, 2016-08-19) COSTA, Juliana Portugal da; VIEIRA, João Paulo Abreu; http://lattes.cnpq.br/8188999223769913
Intelligent Transport Systems are several information and communication technologies applied to vehicular transportation. It is called intelligent due to its memory capacity, sensing, communication, information processing and adaptive behavior. Within this universe, the Vehicular Ad-hoc Networks (VANET) provide communication between vehicles, as well as the telecommunications infrastructure over the roads. In order to achieve connectivity continues with high data rate and low latency, the integration of vehicular networks with LTE system is pointed as a potential access technology solution. There are many challenges found to reach the QoS requirements characteristic of entertainment applications, road safety and traffic efficiency. Therefore, this dissertation proposes a methodology for the study of the impact of radio resource scheduling algorithms for vehicular networks using LTE as the access technology. This study uses a discrete simulation approach, carried out with NS-3 and SUMO tools, to evaluate five scheduling algorithms: RR, PF, TTA, CQA and PSS. The criteria used in the analysis are throughput, delay, packet loss, spectral efficiency, fairness and qualitative analysis of computational complexity. The results indicate for vehicular networks is more appropriate to apply strategies that guarantee high level of fairness between connected vehicles. The evaluation also confirm the need to use algorithms more specific, taking into account the data generation pattern of these kind of application, with the aim to ensure the best performance for the network.
Acesso aberto (Open Access)
Análise do impacto do algoritmo de escalonamento de recursos no desempenho de redes veiculares utilizando o LTE como tecnologia de acesso
(Universidade Federal do Pará, 2016-08-11) CARDOSO, Evelin Helena Silva; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
Intelligent Transport Systems are several information and communication technologies applied to vehicular transportation. It is called intelligent due to its memory capacity, sensing, communication, information processing and adaptive behavior. Within this universe, the Vehicular Ad-hoc Networks (VANET) provide communication between vehicles, as well as the telecommunications infrastructure over the roads. In order to achieve connectivity continues with high data rate and low latency, the integration of vehicular networks with LTE system is pointed as a potential access technology solution. There are many challenges found to reach the QoS requirements characteristic of entertainment applications, road safety and traffic efficiency. Therefore, this dissertation proposes a methodology for the study of the impact of radio resource scheduling algorithms for vehicular networks using LTE as the access technology. This study uses a discrete simulation approach, carried out with NS-3 and SUMO tools, to evaluate five scheduling algorithms: RR, PF, TTA, CQA and PSS. The criteria used in the analysis are throughput, delay, packet loss, spectral efficiency, fairness and qualitative analysis of computational complexity. The results indicate for vehicular networks is more appropriate to apply strategies that guarantee high level of fairness between connected vehicles. The evaluation also confirm the need to use algorithms more specific, taking into account the data generation pattern of these kind of application, with the aim to ensure the best performance for the network.
Acesso aberto (Open Access)
Análise do QoE para streaming de vídeo em redes aéreas 5G mmWave de conectividade dupla
(Universidade Federal do Pará, 2022-02-18) PEREIRA, Ronilson Williame da Silva; SILVA, Marcelino Silva da; http://lattes.cnpq.br/7080513172499497
The evolution in mobile telecommunications has allowed the emergence of new network formats aimed at meeting the growing demand for wireless data, mainly fueled by more viewing of video content. The scarce spectrum available in current cellular networks does not seem to be able to meet this explosion of wireless data, motivating a shift to explore new frequency bands. Currently, one of the major problems of current mobile networks is congestion in denser areas such as concerts, sporting events, and festivals (temporary events), as we have a greater concentration of users, consequently increasing the volume of data traffic. Millimeter-wave (mmWave) communication, frequency bands between 30 and 300 GHz emerges as an essential part for the next generation of fifth-generation cellular networks (5G), as they adopt higher carrier frequencies offering high bandwidth and lower latency. However, system performance degrades due to high propagation loss and the sensitivity of the links to obstacles. To mitigate such factors, this dissertation proposes a dual connectivity 5G mmWave architecture using LTE (Long Term Evolution) and the use of UAVs (Unmanned Aerial Vehicles) as airbase stations to provide connectivity guarantees and quality of experience. in video streaming, one scenario where the proposal might be a suitable solution is to provide coverage for temporary events. Through simulations, an analysis of the Quality of Experience (QoE) was presented about the transmission of 4K videos in order to evaluate the transmission and quality of videos perceived by users. The simulated results show the efficiency of the system for multimedia applications using videos, improving the QoE of wireless users by 43%.
Acesso aberto (Open Access)
Análise e desempenho de tráfego triple play em redes PLC de baixa tensão
(Universidade Federal do Pará, 2011-12-15) CARMONA, João Victor Costa; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
This work is a performance analysis of triple play applications using Power Line Communication technology, making a targeted approach to quality of service and quality of experience. Presents results obtained in residential settings where the use of this technology as a last mile solution proves capable of implementation before the tests with transmission of VoIP calls, streaming high definition video and data. The concept of home network, connecting all the points of a house, has represented a new direction in defining a global standard, in which the transmission of data via the electrical wiring will be one of the technologies employed and the spotlight. Also shown will be evaluated performance metrics such as jitter, bandwidth, packet loss, PSNR, MOS, VQM, SSIM and their correlation.