Programa de Pós-Graduação em Engenharia Elétrica - PPGEE/ITEC

URI Permanente desta comunidadehttps://repositorio.ufpa.br/handle/2011/2314

O Programa de Pós-Graduação em Engenharia Elétrica (PPGEE) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA) foi o primeiro e é considerado o melhor programa de pós-graduação em Engenharia Elétrica da Região Amazônica. As atividades acadêmicas regulares dos cursos de mestrado e doutorado são desenvolvidas principalmente nas Faculdades de Engenharia Elétrica e Engenharia de Computação, supervisionadas pela Coordenação do Programa de Pós-Graduação em Engenharia Elétrica (CPPGEE).

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Agora exibindo 1 - 19 de 19

Acesso aberto (Open Access)
Uma Análise do uso de informacões multiescala no mapeamento da PSNR para pontuacão perceptual
(Universidade Federal do Pará, 2019-11-18) GONÇALVES, Luan Assis; ZAMPOLO, Ronaldo de Freitas; http://lattes.cnpq.br/9088524620828017; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609
The prediction of visual quality is crucial in image and video systems. For this task, image quality metrics based on the mean squared error prevail in the field, due to their mathematical straightforwardness, even though they do not correlate well with the visual human perception. Latest achievements in the area support that the use of convolutional neural networks (CNN) to assess perceptual visual quality is a clear trend. Results in other applications, like blur detection and de-raining, indicate the combination of information from different scales improves the CNN performance. However, to the best of our knowledge, the best way to embody multi-scale information in visual quality characterization is still an open issue. Thus, in this work, we investigate the influence of using multi-scale information to predict the perceptual image quality. Specifically, we propose a single-stream dense network that estimates a spatially-varying parameter of a logistic function used to map values of a objective visual quality metric to subjective visual quality scores through the reference image. The proposed method achieved a reduction of 36.37% and 69.45% for the number of parameters and floating-point operations per second, respectively, and its performance is compared with a competing state-of-the-art approach by using a public image database.
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)
Avaliação de técnica semi-supervisionada de análise de vetor comprimido (C2VA) em imagens de satélites para detecção de mudanças de uso e cobertura da terra
(Universidade Federal do Pará, 2017-12-15) SIRAVENHA, Ana Carolina Quintão; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
Remote sensing image databases and Geographical Information System have the potential to act as accurate tools for environmental monitoring. Carajas Mountains are an important mineral deposit in Brazil and as environmental laws protect a great portion of this region, they have been at the core of conflicts involving human and nature interests. The biggest mining project in Brazil is active in this region (Carajas project) and this analysis aims at identifying the environmental impact caused directly or indirectly by this activity using state of the art methods. This study collects information of land-use and land-coverage from an area larger than 111, 000 km2 including five municipalities, aiming at observing the landscape intervention from a big scale perspective. Therefore, employing the resultant products of the multi-spectral approach called compressed change vector analysis, this work analyses both the environmental changes in five municipalities of the Carajas Mountains: Parauapebas, Canaa dos Carajas, Ourilandia do Norte, Sao Felix do Xingu and Tucuma. From the point of view of the applicability of the proposed tools, it was noticed that the combination of the compressed change vector analysis with the fuzzy clustering is sufficiently efficient for the detection and analysis of changes in land use and land coverage. The quantitative and qualitative evaluation metrics show good accuracy compared to the manually obtained reference images. The results show that in general the vegetative coverage was replaced by pasture lands, which in turn were replaced by urban occupations. The comparison with official statistics and by visual inspection indicate good accuracy of the present study in the estimation of vegetative cover. The presence of environmentally protected areas has prevented the increase of deforestation in the mountains, in which the observed change rates were at least 15% lower than non-protected regions.
Acesso aberto (Open Access)
Beam tracking using deep learning applied to 6G MIMO
(Universidade Federal do Pará, 2024-12-16) OLIVEIRA, Ailton Pinto de; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
This work explores the application of machine learning to enhance beam tracking in 6G MIMO Vehicle-to-Infrastructure (V2I) communications. Beam tracking, essential for sustaining reliable mmWave connections, remains challenging due to the high mobility of vehicular environments and the significant overhead associated with millimeter wave MIMO beamforming. While beam selection has been extensively studied, ML-based beam tracking is relatively underexplored, largely due to the scarcity of comprehensive datasets. To bridge this gap, this study introduces a novel public multimodal dataset, designed in accordance with 3GPP requirements, which combines wireless channel data with multimodal sensor information. This dataset supports the evaluation of advanced data fusion algorithms specifically tailored to V2I scenarios. Furthermore, a custom recurrent neural network (RNN) architecture is proposed as a robust solution for effective beam tracking, leveraging temporal and multimodal data to address the challenges of dynamic vehicular communications.
Acesso aberto (Open Access)
Classificação de eletroencefalogramas epiléticos em estado de repouso com aplicação de classificadores lineares e um atributo derivado da densidade espectral de potência
(Universidade Federal do Pará, 2019-12-04) FIEL, José de Santana; PEREIRA JÚNIOR, Antonio; http://lattes.cnpq.br/3239362677711162
Millions of Brazilians are affected with epilepsy and the access to early diagnosis is crucial for their adequate treatment. However, epilepsy diagnosis depends on the evaluation of longduration electroencephalographic (EEG) recordings performed by trained professionals, turning it in a time-consuming process which is not readily available for many patients. Thus, the present work proposes a methodology for automatic EEG classification of epileptic subjects which uses short-duration EEG recordings obtained with the patient at rest. The system is based on machine learning algorithms that use an attribute extracted from the power spectral density of EEG signals. This attribute is an estimate of functional connectivity between EEG channel pairs and is called debiased weighted phase-lag index. The classification algorithms were linear discriminant analysis (LDA) and support vector machines (SVM). EEG signs were acquired during the interictal state, i.e., between seizures and had no epileptiform activity. Recordings of 11 epileptic patients and 7 healthy subjects were used to evaluate the method’s performance. Both algorithms reached their maximum classification performances, 100 % accuracy and area under the receiver operating characteristic (AUROC) curve, when a feature vector with 190 attributes was used as input. The results show the efficacy of the proposed system, given its high classification performance.
Acesso aberto (Open Access)
Comparison of Satellite Tracking Techniques in Inclined Orbit.
(Universidade Federal do Pará, 2019-01-26) SARMENTO, Thiago Lima; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
This work implements satellite tracking techniques in inclined orbit and compares their performances with other techniques, describing operation and implementing in a simulation environment and in a real control system to generate the performance evaluation of each one. One of the techniques investigated is reinforcement learning. Tracking satellites in inclined orbit is of paramount importance for telecommunications using this type of link, allowing automatic communication maintenance and extending the service life of satellite services in this situation. Algorithms widely used in tracking, both in the literature and in commercial equipment, result in estimates or predictions of satellite position rather than actual position, and require a study of the specific characteristics of the region where the base station is located. The complexity and investments in the tracking technique vary according to the commitment made in the antenna installation and control systems, being necessary to compare the existing methods before their implementation. The work develops the environment necessary to simulate satellite communication, from reception to antenna movement, to analyze the performance of the technique in different controlled situations. Are also presented the actual implementation techniques results in a real antenna control system.
Acesso aberto (Open Access)
Compressão de CSI para MIMO distribuído com processamento centralizado
(Universidade Federal do Pará, 2024-06-18) SILVA, Marcos Davi Lima da; RAMALHO, Leonardo Lira; http://lattes.cnpq.br/7565458988876048; https://orcid.org/0000-0003-3165-1941
In Distributed-MIMO (D-MIMO), a large number of distributed Antenna Points (APs) are coordinated by a Central Unit (CU) to serve a limited number of users with the same time/frequency resources, which brings improvements in spectral efficiency. The success of D-MIMO depends on precoding and power allocation, which can be performed completely centrally on the CU or distributed across APs. The centralized approach has greater spectral efficiency than the distributed implementation, but requires a significant spike in fronthaul traffic due to the exchange of Channel State Information (CSI) between APs and CU. In this work, CSI compression schemes are proposed to enable practical and centralized implementation of D-MIMO. It is shown that depending on the compression configuration, the spectral efficiency can be as good as in the case without compression. Furthermore, this work explores the implementation of multiple-input multiple-output (MIMO) within the framework of the New Radio (NR) architecture. The study evaluates a distributed MIMO deployment using NR signals with compression and evaluates its performance compared to the uncompressed scenario. Through simulations using the NR physical layer, the results also show that the spectral efficiency can be as good as in the uncompressed case depending on the compression configuration. Finally, the simulations with NR signals highlight important practical aspects and the feasibility of implementing D-MIMO in the 5G architecture and beyond 5G.
Acesso aberto (Open Access)
Compression of Channel State Information in Multiple Input Multiple Output Mobile Systems
(Universidade Federal do Pará, 2019-05-24) VILAS BOAS, Brenda; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
The firsts trials of the Fifth generation of wireless networks (5G) are taking place worldwide. A variety of use cases are envisaged, requiring flexible and scalable technologies to meet their key performance indicators. Massive MIMO is a 5G-enabling technology that improves spectral efficiency. To exploit the advantages of MIMO, the transmitter needs to have information about the channel condition (CSI) of each User equipment (UE). 5G is being standardized in Frequency division duplexing (FDD) and Time division duplexing (TDD) operational modes; hence, MIMO has to be feasible in both duplexing modes. As TDD operates downlink and uplink on the same frequency, it can rely on channel reciprocity to acquire the CSI needed to further design precoding and user scheduling, for instance. However, FDD cannot exploit channel reciprocity; therefore, massive MIMO in FDD mode is more challenging because the increasing number of antennas may turn the feedback of CSI impractical. Hence, compressing CSI in MIMO FDD systems is of interest. Furthermore, the use of vast spectrum ranges, sub-6 GHz and mmWaves bands, leads to different channel characteristics. Moreover, the close packaging of antenna elements increases the spatial correlation among a MIMO array. Consequently, this correlation can be exploited to leverage compression of CSI. This dissertation presents an overview of CSI compression methods, proposes an heuristic transform coding method with low computational cost, and do a systematic evaluation of the transform coding methods based on realistic MIMO channel simulations. Besides, the impact of different 5G use cases and design of transmitter and receiver antennas are also included on the evaluation to chose
Acesso aberto (Open Access)
Deep learning software-based holdover for PTP IEEE 1588 synchronization in 5G networks
(Universidade Federal do Pará, 2023-03-28) DUTRA, Rodrigo Gomes; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
This work proposes evaluates software-based algorithm mechanisms for maintaining the synchronization of a real-time clock in holdover operation when the timing reference input is unavailable. Three algorithms, Autoregressive Integrated Moving Average (ARIMA), long short term memory (LSTM), and Transformer networks, are implemented and trained using timestamps and temperature data acquired while the slave clock is locked to a master clock. When the slave clock loses its reference, the algorithm-based models take over and control the clock. The proposed method is evaluated on a testbed of IEEE 1588 Precision Time Protocol (PTP) clocks based on field-programmable gate arrays, where nanosecond-accurate timestamps are collected for offline analysis. The models are evaluated using two clocks, one cost-effective, cristal oscillator (XO), and one robust, oven controlled cristal oscillator (OCXO), in both constant and variable temperature scenarios. The results show that all algorithms can sustain clock synchronization accuracy within reasonable Time division duplex (TDD) synchronization limits over intervals of 1000 seconds in all temperature and clock scenarios, with the transformerbased holdover mechanism outperforming the statistical approach and LSTM network. This cost-effective software-based approach proves to be feasible for increasing clock accuracy during holdover operation and can be generalized to other holdover contexts, such as in a Global Navigation Satellite System (GNSS) scenario.
Acesso aberto (Open Access)
Estimação de crosstalk em redes c-ran com fronthaul de cobre
(Universidade Federal do Pará, 2019-02-26) MONTEIRO, Waldeir de Brito; BORGES, Gilvan Soares; http://lattes.cnpq.br/7696860178450119; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
The implementation of the 5G standard will make the current mobile network architectures evolve towards C-RAN configurations, which are characterized by concentrating processing on a base station, from where the signal is distributed to remote antennas. To maintain uniform coverage, these systems rely on a dense network of low-power antennas scattered throughout buildings. This approach increases the complexity of the network’s Multi Input Multi Output (MIMO) system, which may hamper certain measurements involving equipment at both ends of the link. This work presents a method for the estimation of Far End Crosstalk (FEXT) and Insetion Loss (IL) using only one end of the link in order to bavoid synchronization problems present in complex MIMO systems. Compared to other methods with similar proposals, the presented technique combines a simpler approach to a lesser degree of dependence on dual loop measurements, besides complementing techniques that can accomplish these measurements, but in a restricted range of frequencies
Acesso aberto (Open Access)
Estimação de descarga de dispositivo IoT usando deep learning com otimização NSGA-II
(Universidade Federal do Pará, 2024-02-28) MACEDO, Wilson Antonio Cosmo; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609
The increasing adoption of IoT (Internet of Things) network applications highlights the need to optimize energy management in these systems, because energy efficiency is crucial for the adaptability of IoT implementations. This study analyzes the discharge curves of a rechargeable battery in an IoT network context utilizing LoRa (Long Range) communication and various sensors, with the objective of generating multiple discharge curves to estimate the battery behavior in this scenario. These curves were used to train a Multilayer Artificial Neural Network (ANN), implementing Deep Learning techniques, where the ANN architecture was outlined using the NSGA-II (Non-dominated Sorting Genetic Algorithm II) Multi-objective Optimization algorithm. This resulted in models capable of estimating the battery discharge time by analyzing a segment of the discharge process observed by the model with a mean squared error of approximately two minutes for the most efficient model found. This result represents a very positive margin, considering that the duration of the discharge tests extends to approximately seventy-one hours and the data collection sampling rate is one minute.
Acesso aberto (Open Access)
MAERNI - Módulo de avaliação da exposição à radiação não ionizante proveniente das antes de transmissão de TV digital e rádio FM para uma ferramenta com o ambiente virtual 3D
(Universidade Federal do Pará, 2018-10-09) GUERREIRO, Charllene de Sousa; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
In recent years given the technological advancement of the communication media, and the increasing of users demand who wants a high quality of these services offered to them, the companies have increased the number of Radio Base Stations in cities, where many of these are located in environments with high housing density. Considering that each antenna or set of antennas present in these stations have an electromagnetic field of radiofrequency and transmit radiation, the concern with the population living in the adjacency of the transmitting antenna is the studies object of systems than regulate the companies that offer radiofrequency services, as well as, is the object of studies that aim not only to discover the effects of the contact with the ionizing and non-ionizing radiation present in these fields, but also to find out if the standard established for the regulation of services is being fulfilled. In this work presents the stages of development of a module, which consists of an extension added to the simulator for planning mobile communication networks (SIMPLARCOM). The module proposed allows, through the Virtual Reality environment (VR), to build and configure different scenarios, as well as the parameters of the transmission antenna, to provide an environment for non-invasive tests to evaluate non-ionizing radiation exposure; and identify potential insecure areas for housing, providing information for aid in decision-making regarding the relocation of transmitter antennas and aiming to decrease the ERP (effectively radiated Power) radiated by these Antennas. The module considers the guidelines present in resolution Nº. 303, published by the National Telecommunications Agency (ANATEL). In the results obtained is possible, navigate through the constructed scenario and check the value of the received power, the field intensity, the operation frequency, the antenna being analyzed and whether a certain point in the scenario is or is not receiving radiation at according to the threshold permitted by ANATEL.
Acesso aberto (Open Access)
Mapeamento de bits para adaptação rápida a variações de canal de sistemas QAM codificados com LDPC
(Universidade Federal do Pará, 2017-09-29) CORRÊA, Fernanda Regina Smith Neves; UCHÔA-FILHO, Bartolomeu Ferreira; http://lattes.cnpq.br/7752341440632617; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
Low-Density parity-check (LDPC) codes are being adopted as the error correction strategy in di erent system standards, such as the G.hn (home networking standard) and the IEEE 802.11n (wireless local standard). In these LDPC-coded quadrature amplitude modulation (QAM) systems, mapping the LDPC coded bits properly to the di erent sub-channels considering the fact that sub-channels have di erent qualities ensures an improved overall system performance. Accordingly, this thesis presents a new bit mapping technique based on the assumption that bits transmitted in \good" sub-channels, help bits transmitted in \bad" sub-channels. This can be made possible through some restrictions to be imposed on the associated Tanner graph, akin to Root-LDPC codes. An optimization of the root-like bit mapping through extrinsic information transfer (EXIT) charts analysis is also presented. We show that this mapping has the advantage of a reduced optimization search space when applied to single-carrier based systems. Moreover, in situations where the search space is not só reduced, such as in orthogonal frequency division multiplexing (OFDM)-based applications, we arrive at a rule of thumb associated with the bit mapping constraints that practically eliminates the need for an optimization. Finally, a study of the impact of the level of reliability imbalance across the sub-channels on the performance of the root-like bit mapping is presented. Simulation results show that the new bit mapping strategy improves performance, and that in the presence of channel variations, the system can, adaptively, apply a new bit mapping without the need of a complex optimization, which can be very useful in practical systems.
Acesso aberto (Open Access)
Uma metodologia temporal para avaliação do desempenho de códigos concatenados em sistemas OFDM para transmissão de vídeo 4K-UHD
(Universidade Federal do Pará, 2024-08-16) COSTA, Thiago de Araújo; CASTRO, Bruno Souza Lyra; http://lattes.cnpq.br/1897829604434609; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609
The communication channel is a critical part of the process of information degradation. In the 4K ultra-resolution video transmission domain, the communication channel is a crucial part where information degradation occurs, inevitably leading to errors during reception. To enhance the transmission process in terms of fidelity, advanced technologies such as digital video broadcasting terrestrial (DVB-T) and its evolutionary successor, digital video broadcasting terrestrial second generation (DVB-T2), are utilized to mitigate the effects of data transmission errors. In the transition, a notable change is the replacement of the concatenated channel coding pairs. Within this scenario, this research presents an innovative methodology for the temporal analysis of 4K ultraresolution video quality under the influence of additive white Gaussian noise (AWGN) and Rayleigh channels. This analytical endeavor is facilitated through the application of concatenated coding schemes, specifically, the Bose-Chaudhuri-Hocquenghem concatenated low-density parity check (BCH-LDPC) and Reed-Solomon concatenated convolutional (RS-CONV) coders. A more comprehensive understanding of video quality can be attained by considering its temporal variations, a crucial aspect of the ongoing evolution of technological paradigms. In this study, the Structural Similarity Index (SSIM) serves as the main metric for quality assessment during simulations. Furthermore, the simulated Peak Signal-to-Noise Ratio (PSNR) values validate these findings, exhibiting consistent alignment with the SSIM-based evaluations. Additionally, the performance of the BCH-LDPC significantly outperforms that of RSCONV under the 64-QAM modulation scheme, yielding superior video quality levels that approximate or surpass those achieved by RS-CONV under QPSK (Quadrature Phase Shift Keying) modulation, leading to an increase in spectral efficiency. This enhancement is evidenced by SSIM gains exceeding 78% on average. The computation of average gains between distinct technologies in video quality analysis furnishes a robust and comprehensive evaluation framework, empowering stakeholders to make informed decisions within this domain.
Acesso aberto (Open Access)
Metodologias de discretização espacial sem malha baseadas nos potenciais de Coulomb e Lennard-Jones para o método radial de interpolação por pontos (RPIM) aplicadas para solução numérica das equações de Maxwell
(Universidade Federal do Pará, 2017-12-04) SOUSA, Washington César Braga de; RABELO, Wilson Ricardo Matos; http://lattes.cnpq.br/7978676206209168; OLIVEIRA, Rodrigo Melo e Silva de; http://lattes.cnpq.br/4768904697900863
In this thesis, three new particle interaction methods based on the Coulomb's and Lennard- Jones' potentials have been developed (and computationally implemented), aiming to generate meshless spatial discretization which can be used to the Radial Point Interpolation Method (RPIM) for solving partial di erential equations. These new methods, called Coulomb Law Discretization Method (CLDM), Electric Charge Gaussian Gradation Method (ECGGM) e Lennard-Jones Discretization Method (LJDM),employ adapted versions of Coulomb's and Lennard-Jones' vector forces equations for obtaining a balanced distribution of nodes in space (equilibrium state), in order to achieve high discretization quality of space and complex structures. For this aim, a new quality metrics is introduced. This doctoral thesis is presented as an aggregation of three scienti c papers, which present respectively the methods: CLDM, ECGGM and LJDM. The RPIM and the uniaxial perfectly matched layers (UPML) are used for solving Maxwell's equations in time domain for 2D (TMz mode) and 3D problems. The CLDM, ECGGM and LJDM methods (each in conjunction with the RPIM method) are applied to electromagnetic scattering problems, based on circular, elliptic and triangular metal cylinders (2D case). The LJDM / RPIM method is applied to the 3D case. The obtained results are in accordance with analytical solutions.
Acesso aberto (Open Access)
Modelling and mitigation of alien crosstalk for DSL systems
(Universidade Federal do Pará, 2017-12-11) GOMES, Diego de Azevedo; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284; PELAES, Evaldo Gonçalves; http://lattes.cnpq.br/0255430734381362
G.fast is the most recent ITU-T standard for DSL transmission, which targets copper topologies with short distances and adopts a bandwidth of 106 MHz extensible to 212 MHz. In several situations, G.fast systems will be composed by or coexist with uncoordinated (or alien) lines, which are sources of strong crosstalk, because these lines are not part of the vectored group. This document presents a formulation to explain the performance of the alien crosstalk mitigation methods according to the number of alien lines in a certain environment, the mechanism that de nes the interference correlation of it and an alien crosstalk mitigation method for downstream DSL transmission impaired by multiple interferers called AMMIS. Simulation results show that alien crosstalk mitigation methods found in the literature can indeed improve the performance of G.fast systems, but only under speci c conditions. We have contrasted these situations and we provide guidelines about the feasibility of the crosstalk mitigation techniques in scenarios with distinct number of alien lines. Additionally, the AMMIS shows promising results in relation to the bit rate when compared with literature methods in scenarios with a large number of interferers, with the additional advantage of allows power savings. As support for the simulations, we also present a set of alien crosstalk measurements.
Acesso aberto (Open Access)
Modelo de propagação usando dois raios com modificação de fase para mobilidade aplicado a receptor LoRa sobre rio.
(Universidade Federal do Pará, 2024-09-19) RIBEIRO, Lucian Morais; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609
As predicted by experts, there has been exponential growth in the number of IoT devices used by the general population. Among these devices, one of the most notable groups is the Long Range (LoRa) devices. The most relevant feature of LoRa technology is its low energy consumption, while simultaneously providing a wide coverage area. If applied in the Amazon region – a densely forested, humid area with populations far from urban centers and with very little infrastructure – this technology could offer a new range of services to the region’s inhabitants, including services involving communication on the move. Starting from the principle that the most well-known propagation models are not adjusted to the specificities of the Amazon region, nor do they consider the phase variations caused by receiver movement – which makes radio links difficult to predict – we aim to present solutions to this problem through this work, which presents adjustments to the Two-Ray propagation loss model to accommodate LoRa communications over the Amazon rivers when the receiving devices are in motion. The proposed model is compared to the standard Two-Ray Model, which serves as the baseline, and achieves better results. Additionally, the study evaluates the impact of tides on the propagation loss of LoRa signals in river environments.
Acesso aberto (Open Access)
. Sistema de monitoramento de vazão de água utilizando tecnologia LoRA
(Universidade Federal do Pará, 2024-12-17) CASTRO, Jucicleber Francisco da Silva; BORGES, Gilvan Soares; http://lattes.cnpq.br/7696860178450119; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
The discussion on the rational use of water has gained worldwide momentum in recent years. The United Nations (UN) treats the issue with due priority, including it in its Sustainable Development Goals (SDG 6). Brazil, in turn, is striving to adhere to this context with the implementation of the new regulatory framework for the sanitation sector, enacted in 2020. Despite the well-deserved importance given to sanitation in recent years, there is a need to invest resources in the area in order to achieve the adequate social reach of water for all, where the absence of these policies in isolated and socially excluded regions is latent. Technologically, within this scenario, it is possible to envision the Internet of Things (IoT) as an important differentiator to be used as a social inclusion technology through the application of low power wide area networks (LPWAN), with LoRa technology standing out as one of the most promising for building communication networks aimed at IoT applications. This work aims to meet this demand through a proposal for water flow sensing using LoRa networks, as a subsequent case study in isolated communities in future work. This proposal for a water flow monitoring system is based on an architecture involving the installation of a digital ultrasonic hydrometer at a water collection point for data collection and real-time monitoring. The bench tests involving the installation of the hydrometer were carried out with the initial aim of communicating with the LoRa-ESP32-Wi-Fi v2 module. With the data collected, it was possible to transmit it to a broker server using MQTT protocol that is consumer for a dashboard that was build using a Node-RED for water consumption monitoring analysis, making it easier to identify leaks and develop strategies to reduce losses when implementing the prototype.
Acesso aberto (Open Access)
Sistemas fotovoltaicos aplicados em cenário de rede 5G
(Universidade Federal do Pará, 2020-01-31) OLIVEIRA, Carmela Souza; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434
With the deployment of the next generation of mobile networks, a significant increase in data consumption is estimated and, consequently, a substantial impact on energy consumption. In light of this scenario, it is interesting to think of alternative sources that can meet this energy demand and additionally act to mitigate greater environmental impacts. Based on this economic and, above all, environmental perspective, this work proposes the use of a photovoltaic system as a strategy for the potentialization of energy consumption in a less aggressive way to the environment. The experiments carried out evaluate the viability of the proposal from the implementation in two RAN (Radio Access Network) architectures that can be employed to the new generation (5G). The results demonstrate the financial viability in the installation of photovoltaic system when compared to conventional sources of power generation.