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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Acesso aberto (Open Access)
Uma análise técnico-econômica para implantação de arquiteturas centralizadas de redes de telefonia móveis
(Universidade Federal do Pará, 2018-03-06) SOUZA, Daniel da Silva; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
Upon the the challenges proposed by the fifth generation of mobile networks, the architecture of C-RAN (Centralized Radio Acess Network) has gained space by supporting high-capacity ultra-densas networks of next generation and offering economies. This dissertation proposes a TCO (Total Cost of Ownership) for C-RAN, CAPEX (Capital Expenditure), OPEX (Operational Expenditure) and these are the fundamental criteria in the field of investment assessment and projection. It is soon presented with a higher level of detailing as to the investment aspects, which are of great relevance to the architectural landscape of mobile communication networks. In this way, this work is conducted in order to evaluate the economic context of the implementation of a centralized architecture, based mainly on the financial aspects that service operators need to plan before deploying a new Mobile Access Network. The proposed model is used in a case study where the total cost of implementation and operation of the distributed and centralized architectures is compared taking into account several specific scenarios. The results point to an economy in the centralized scenarios and highlight the most relevant economic aspects in the planning of C-RAN.
Acesso aberto (Open Access)
Avaliação de técnicas de compressão de sinais Para o fronthaul
(Universidade Federal do Pará, 2019-11-27) BRITO, Flávio Mendes de; KLAUTAU JÚNIOR, Aldebaro Barreto da Rocha; http://lattes.cnpq.br/1596629769697284
The growing data demand of mobile networks has motivated the creation and evolution of architectures aiming to supply such transfer requirements. To meet these requirements, a number of challenges need to be met, including data transfer at the link between the Base Station Unit (BBU) and the Remote Radio Head (RRH). Known as fronthaul, this link requires high speed information transfer and one method that allows to tranfer more data using the same rate is data compression. Therefore, this study aimed to evaluate different techniques used in fronthaul data compression. Initially, the efficiency of some quantizers such as the scalar quantizer (SQ), twodimensional vector (VQ) and the Trellis Coded Quantization (TCQ) was verified. The analysis consists of combining these quantizers with resampling, Block Scaling and Huffman coding. In both analyzes, it was found that the system using TCQ as quantizer obtained the best relationship between Error Vector Magnitude (EVM) and computational cost, offering an EVM lower than the scalar quantizer and a computational cost lower than the vector quantizer.
Acesso aberto (Open Access)
Clustering-driven equipment deployment planner and analyzer for wireless non-mobile networks applied to smart grid scenarios
(Universidade Federal do Pará, 2018-03-16) VRBSKÝ, Ladislav; SILVA, Marcelino Silva da; http://lattes.cnpq.br/7080513172499497
The modern power grids, known as smart grids, rely on various advancements, one of them being the introduction of bi-directional communication. In some cases, data exchanged in the network is of critical importance. The data transmissions need to meet speci c delay limits set by the regulatory agencies in order for the smart grid to function properly. Meeting these standards allows the use of new applications of monitoring, control and system protection, resulting in a more e cient, stable and environment-friendly system. This thesis presents a methodology for analysis and planning of wireless communication networks for smart grid, which uses a clustering algorithm to determine the optimal positions of the routers and gateways of the network to be installed. After, it calculates the delay for each Intelligent Eletronic Device that is a network subscriber. This way, an analysis can be made to obtain the Quality of Service requested for a speci c network setup in a speci c scenario. The results obtained in the performed case study show that it is possible to achieve a network topology that satis es the maximum delay requirements of 100% of its subscribers, using WiMAX or a combination of Wi-Fi and WiMAX. Also, the thesis explores a restricted communication mode that can temporarily suspend the transferences of non-critical data. In most scenario con gurations, the restricted mode delivers all the data within the maximum delay. The software implementation of the proposed model is made publicly available under open-source license, so that anyone, including researchers, or private and public companies, can take advantage of it. The model presented in this thesis is customizable, allowing the use of other technologies and be used with other networks, including scenarios that are not related to smart grid.
Acesso aberto (Open Access)
Custo total de propriedade para infraestruturas de comunicações 5G para smart grid
(Universidade Federal do Pará, 2019-01-24) MELO, Paulo Tássio da Luz; SILVA, Marcelino Silva da; http://lattes.cnpq.br/7080513172499497
Smart Grid communications networks are considerably different from the traditional communica-tion systems used to access the Internet when considering users, applications, Quality of service and, especially, the impacts/losses due to malfunctions. Such data networks are generally owned and used exclusively by electrical system operators and require a high financial investment. There fore, this paper presents an economic analysis to compare different possibilities of data network deployment for the Smart Grid. The results showed that for the proposed scenario, 5G compared toother technologies, obtained the best evaluation for the implementation of the communication of a network of data applied to the Smart Grid, since the data of Quality of Service and the results obtained in the Total Cost of Property, showed that in the medium and long term the 5 Ghas its lower cost when faced with expenditures of other communication technologies, presenting 100% and 99.02% of IEDs with Quality of Service for uplink and downlink maximum, and the average IEDs served, is 100% for uplink and 99.4% for downlink in NORMAL and STRIP mode, respectively.
Acesso aberto (Open Access)
Estratégia para otimização de offloading entre as redes móveis VLC e LTE baseada em q-learning
(Universidade Federal do Pará, 2018-08-31) SOUTO, Anderson Vinicius de Freitas; OLIVEIRA, Edvar da Luz; http://lattes.cnpq.br/1840754571733900; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
The increase in the consumption of data traffic is motivated by the increasing number of devices like smartphone and tablets, since there is a need to be connected with everything and with everyone. Applications such as streaming video and online games require a higher rate of data transmission, this high demand corroborates the overload of mobile networks based on radio frequency, so as to culminate in a possible shortage of the RF spectrum. Therefore, this work seeks to optimize offloading between LTE and VLC, and for this a methodology based on reinforcement learning called Q-Learning is used. The algorithm uses as input the environment variables that are related to the signal quality, density and speed of the user to learn and select the best connection. Therefore, the results of the simulation show the efficiency of the proposed methodology in comparison with the predominant RSS scheme in the area literature. as it has been proven by QoS metrics to support higher data rates, as well as ensuring an 18% improvement over service interruptions as the number of users increases in the system.
Acesso aberto (Open Access)
Estratégias de planejamento para otimização do consumo residencial de energia elétrica: uma abordagem baseada em smart home e sistemas fuzzy
(Universidade Federal do Pará, 2017-08-04) ANDRADE, Sérgio Henrique Monte Santo; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
Residential energy consumption has grown steadily over the last decades, becoming a problem for companies in the electricity sector, for consumers and for the environment. The traditional measurement systems are not sufficient and have limitations in providing adequate real-time information about consumption. As also, they are not prepared to deal with variable energy costs in the context of a market with dynamic prices that depend on the energy mix. The future of electric grid, called Smart Grid, will not only be designed with measurements based on the residences, but also on the individualized equipment consumption level. From the residential side, consumers generally suffer from a lack of information on the specific equipment energy consumption impact and, consequently, on the required behavior to reduce its consumption. In this context, this work aims on a smartphone monitoring system concept, to control energy using fuzzy logic, in order to provide to the user ways to maintain his energy consumption, through consumption profiles, within the user-defined consumption patterns. The energy reduction demand through the consumption profiles working with habitant dependence degree on the electrical equipment present in the residence, promote a smaller impact on inhabitant well-being and the daily life.
Acesso aberto (Open Access)
Extensão do plano de controle sem fio para ambientes experimentais outdoor
(Universidade Federal do Pará, 2017-12-14) NÚÑEZ, Alexsander; ABELÉM, Antônio Jorge Gomes; http://lattes.cnpq.br/5376253015721742
The use of experimental wireless environments is a powerful tool for validating surveys in Future Internet, testing products and services. USA, Europe, Japan, Brazil, among other countries, through initiatives such as FIRE, GENI, WISHFULL and FIBRE, already provide such environments for researchers. However, the topology of these environments, in the wireless and outdoor context, is still very limited due to the need for wired infrastructure to control the devices. In this way, this dissertation presents a wireless control plan proposal for these outdoor experimental environments, maintaining its characteristics of use and adding functionalities through the proposed control architecture based on the framework called Orchestrator for Wireless Experimental Networks of Multiple Jumps Defined by Software (OREx).
Acesso aberto (Open Access)
Fuzzy c-means based gateway placement algorithm for lorawan
(Universidade Federal do Pará, 2020-02-27) MATNI NETO, Nagib Coelho; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221; HTTPS://ORCID.ORG/0000-0003-2162-6523; ROSÁRIO, Denis Lima do; http://lattes.cnpq.br/8273198217435163; https://orcid.org/0000-0003-1119-2450
Low Power Wide Area Network (LPWAN) technologies recently gained interest from the research and industrial community. Internet of Things (IoT) devices communicate directly with gateways, which act as bridges towards a central network server and the Internet. In this context, it is important to study how to place multiple gateways in an area considering Quality of Service, Capital expenditure (CAPEX), and operational expenditure (OPEX) requirements. This is because network planning and optimization are considered to be significant issues that impact on the application performance, CAPEX, and OPEX. In this master thesis, we propose an optimal LoRa gateway placement (PLACE). It considers the Gap statistics method to find the number of LoRa gateway, which is used to compute the gateway placement using the Fuzzy C-Means algorithm. Simulation results show that PLACE reduced in 36% the CAPEX and OPEX compared to the grid and random gateway placement, while keeps a similar Packet Delivery Ratio.
Acesso aberto (Open Access)
Gestão da tecnologia da informação na educação: o uso dos jogos educativos digitais e os impactos na motivação e no aprendizado
(Universidade Federal do Pará, 2018-08-24) OLIVEIRA JÚNIOR, Walter dos Santos; ALVES, Osvando dos Santos; http://lattes.cnpq.br/9650974803851836; OLIVEIRA, Roberto Célio Limão de; http://lattes.cnpq.br/4497607460894318
Entre as recentes inovações do processo de ensino aprendizado, tem se destacado o uso dos jogos educativos digitais. Conhecer a sua eficácia é responsabilidade de educadores, desenvolvedores, pesquisadores e gestores. Este trabalho investiga a implantação de um aplicativo digital chamado “Matematicando” em escolas públicas do estado do Pará. Ao longo de seis meses no ano de 2017, foi acompanhada a implantação deste aplicativo, observados a evolução das notas escolares de 157 alunos, do quinto ano do ensino fundamental, na faixa etária dos 11 aos 13 anos em duas cidades paraenses. Aditivamente foi pesquisada a relação do uso do jogo educativo digital e a motivação de alunos e professores em outras 75 escolas de um município do Pará. O experimento examinou a correlação entre o uso do jogo educativo digital, os rendimentos escolares como variáveis independentes e aspectos relacionados infraestrutura, aos alunos e aos professores, como variáveis dependentes. Para a análise da evolução das notas a população amostral foi dividida entre estudantes expostos ao jogo e alunos não jogadores. Os resultados revelaram que houve avanços nas notas de 12% entre os alunos que tiveram contato com o jogo e um decréscimo de -1,0% entre aqueles que não utilizaram o jogo. Quando comparadas as horas de exposição ao jogo, os alunos que mais utilizaram (192 horas) apresentaram rendimento 45% superior em comparação aos que utilizaram menos (24 horas). Quanto à correlação entre a presença de conexão a Internet e o laboratório de informática e o uso do jogo, foi encontrado um avanço médio entre aquelas que não possuem nem Internet tampouco laboratório um avanço de 2% nos rendimentos, ao passo que as escolas conectadas a Internet e que possuem laboratório de informática cresceram em média 14%. A partir dos resultados obtidos, espera-se contribuir com gestores e educadores quanto ao uso da tecnologia e da gestão da informação no cotidiano de instituições de educação, especialmente no que se refere a melhorias das múltiplas relações que colaboram com um ambiente educacional mais eficiente.
Acesso aberto (Open Access)
Heurística para provisionamento dinâmico de recursos de hardware em redes híbridas de acesso via rádio considerando o efeito de maré
(Universidade Federal do Pará, 2020-03-06) FALCÃO, Igor Wenner Silva; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
The increase in the volume of services and applications, in addition to the accelerated growth in wireless access demands, represent significant challenges for the fifth generation of mobile networks, the 5G network. This increase in the volume of applications is a reflection of the growing number of devices connecting to the network, consuming data expansively, generating high data load. Another point of great impact is the large-scale daily migration of people in urban centers, causing the so-called Tide Effect. This promotes the space-time fluctuation of traffic throughout the day, making it difficult to control and manage the network (low efficiency in the use of hardware resources, load imbalance, underutilization and idleness of resources). Based on these indications and considering the knowledge of the service operators, data from the movement of users in New York City were extracted through an LBSN (Location-Based Social Network). Considering the expected high traffic demand for 5G and the problems arising from the Tidal Effect, this dissertation proposes a heuristic with two approaches to provisioning hardware resources (one based on the aggregate throughput and the other on the number of connected users). The results show that the network provisioning met the traffic variability of the scenario used, reducing the Probability of Blocking by 3.7%, maximizing the efficiency of the Base Band Unit (BBU) and quantifying the Small Cells (SCs) necessary to meet user demand.
Acesso aberto (Open Access)
Implantação de sistema fotovoltaico de baixo custo em arquitetura de rádio centralizada
(Universidade Federal do Pará, 2020-01-31) SARAIVA, Paline Alves; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
The growing demand for higher data rates and better quality of Internet services has resulted in high investments in mobile network infrastructure by operators. In this context, Centralized Radio Architecture (CRA) is a promising solution that relies on centralizing, sharing, and better allocating network resources, resulting in reduced deployment and operation costs when adequately planned. While the benefits of CRA are numerous, this cost reduction can also be enhanced through the adoption of alternative energy sources. One of the options for this, it is Growing demand for higher data rates and better quality of Internet services has resulted in high investments in mobile network infrastructure by operators. In this context, Centralized Radio Architecture (CRA) is a promising solution that relies on centralizing, sharing, and better allocating network resources, resulting in reduced deployment and operation costs when adequately planned. While the benefits of CRA are numerous, this cost reduction can also be enhanced through the adoption of alternative energy sources. One of the options for this equipment through optimization approaches, considering the energy demand of CRA, represents a challenge to be overcome. To this end, this work proposes a strategy to minimize the cost of imple- menting a photovoltaic system by reducing the number of inverters, formulated as an Integer Linear Programming (ILP) problem, to further reduce costs related to CRA. From the results, it is evident that the proposed optimization technique, implied in the average reduction of the Total Cost of Ownership (TCO) of the photovoltaic system in about 0.02 million reais, as well as in the environmental sustainability through the reduction of carbon dioxide emissions (CO2) in the atmosphere.
Acesso aberto (Open Access)
Influência de incrustações na eficiência de trocadores de calor: o caso da perda de produtividade em hidrelétricas
(Universidade Federal do Pará, 2011-09-16) LOPES, Antonio Dimael de Almeida; MACEDO, Emanuel Negrão; http://lattes.cnpq.br/8718370108324505
Heat exchangers are devices widely used in industrial processes, and various applications, in some situations to heat a fluid other cooling fluid, but that regardless of where it is applied usually the heat exchanger has a great responsibility. The heat exchangers are also used in power plants, because plants have hydraulic power generation systems that perform work, therefore generate energy as heat and this must be controlled so as not to raise the temperature of operation of the system to levels that impede the operation, in this context is the use of heat exchangers for the most part, hydraulic power plants use water as cooling fluid, which is collected directly from the reservoir, this mode of operation is advantageous, when we look only to the degree of complexity, because in most cases the cooling systems of power plants are open-ended, is, water is captured from the reservoir feeds the heat exchanger is then discarded into the river, but when we analyze the productivity item, we open system in which we have a disadvantage, as the volume of water is high it is difficult to appropriate treatment for use in industrial heat exchangers, such as this occur the problems of corrosion and fouling also, causing losses of efficiency in heat exchangers and therefore in the process to which it is inserted, reaching even to stop the process entirely. This work will be assessed if the application of an automated mechanical cleaning process to eliminate or minimize the loss of efficiency of heat exchangers of the cooling system water generator.
Acesso aberto (Open Access)
A machine learning framework for ECG biometric system
(Universidade Federal do Pará, 2020-02-28) SANTOS, Alex Barros dos; ROSÁRIO, Denis Lima do; http://lattes.cnpq.br/8273198217435163; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221; https://orcid.org/0000-0003-2162-6523
The new environment of IoT and the deployment of 5G networks have been generating a huge amount of data. Developers are creating new applications and redesigning other ones completely. Also, a society greater concern with health increases the demand for health services provided with the usage of wearable devices that are getting cheaper. Moreover, the applications require more data protection and privacy. Thus, biometrics has become one of the primary mechanisms for protecting information used by users in all kind of systems and applications. This work investigates the use of an ECG signal in biometrics systems approaching machine learning techniques. This signal is a new alternative not only to increase current safety standards by providing the individual’s continuous authentication but also to assess health with cardiac monitoring already well established in medicine by evaluations. In this context, this master’s thesis proposes some processing steps to data sets, improving its quality that allows it to be used as a reliable source of biometric data. We define techniques for extracting signal considering mobile application constraints and design a structure that allows the use of ECG as a biometric signal in a scalable and heterogeneous environment considering different machine learning techniques such as Support Vector Machine, Random Forest and Neural Networks. The set of our proposed feature extraction, processing steps of data set and a machine learning model are the main contributions of this work.
Acesso aberto (Open Access)
Metodologia de monitoramento de epidemias: uma abordagem baseada em redes neurais artificiais
(Universidade Federal do Pará, 2018-01-26) SILVA, Wilson Rogério Soares e; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567
Dengue fever is a viral infectious disease that is present in more than 100 countries worldwide. In underdeveloped countries such as Brazil, this pathology presents dramatic contours when prevailing socioeconomic factors are added, such as the precarious basic sanitation conditions characteristic of large cities. When we associate this scenario with the Amazon we perceive that the geographic location and climatic conditions of this space contribute to the occurrence of this disease is dimensioned. The Ministry of Health provided data from a survey that found that of the 409,073 reported cases in the North, 106,433 occurred in the state of Pará, where the municipalities with the highest reports of dengue cases are: Belém, Parauapebas, Altamira and Santarém. This work proposes a methodology to monitor epidemics based on the use of Artificial Neural Networks, based on a case study of prediction of dengue cases in the state of Pará. To this end, a system was developed that uses a public database of cases of the disease, of weekly occurrence of the municipalities already mentioned. In addition, it performs the statistical analysis of the series of municipalities showing complexity, and justifying the use of neural networks for this type of problem. It performs the layer adjustments, time window of the trained neural model which in this case is a variation known as recurrent neural network. It implements a module for issuing alerts to detect a sudden increase in new cases of the disease, contributing to the decision-making of public health agencies and their respective actions to control epidemics in the municipalities under study. From our analysis we can conclude that the methodology described in the research is valid for predicting dengue cases using neural networks, anticipating combat actions and contributing to decision making, which can be used by public health managers . And that the use of recurrent neural networks can adjust to the complexity of the series studied. The results demonstrated that the RNA model, for the current scenario, performed well in the epidemiological prediction, reaching satisfactory accuracy
Acesso aberto (Open Access)
Metodologia de predição de perda de propagação e qualidade de vídeo em redes sem fio indoor por meio de redes neurais artificiais
(Universidade Federal do Pará, 2018-02-27) CRUZ, Hugo Alexandre Oliveira da; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This dissertation presents a methodology that aims to assist the planning of indoor wireless network systems, which require prior knowledge of the environments in which they will be deployed. Thus, accurate signal analysis is necessary by means of a statistical empirical approach, which takes into account some factors that influence the propagation of the indoor signal: architecture of the buildings; arrangement of furniture inside the compartments; numbers of walls and floors of various materials, and the spread of radio waves. The methodology adopted is based on measurements with a cross-layer approach, which demonstrates the impact of the physical layer in relation to the application layer, in order to predict the behavior of the Quality of Experience (QoE) metric, called Peak signal- to-noise ratio (PSNR), in 4K video streams on 802.11ac wireless networks in the indoor environment. In order to do so, measurements were performed, which demonstrate how the signal / video degrades in the studied environment. It is possible to model this degradation by means of a computational intelligence technique, called Artificial Neural Networks (RNA), in which input parameters are inserted as, for example, the distance from the transmitter to the receiver and the number of walls crossed in order to predict loss of propagation and loss of PSNR. In order to evaluate the predictive capacity of the proposed methods, the values of the Root Mean Sqare (RMS) errors between the measured and predicted data were obtained by the prediction methods loss of propagation and loss of PSNR, with respective values of 2.17 dB and 2.81 dB.
Acesso aberto (Open Access)
Mobility and cloud management in wireless heterogeneous 5g networks
(Universidade Federal do Pará, 2020-06-30) PACHECO, Lucas de Sousa; ROSÁRIO, Denis Lima do; http://lattes.cnpq.br/8273198217435163; HTTPS://ORCID.ORG/0000-0003-1119-2450; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221; https://orcid.org/0000-0003-2162-6523
The network mobility management branch is responsible for the protocols and actions taken by the network to ensure connectivity and the continuity of services consumed by mobile users. In this dissertation we analyse how next-generation networks pave the way for the distribution of video in vehicular networks (VANETs), composed by an heterogeneous ultra-dense infrastructure, joining existing wireless communication technologies to obtain greater spectral efficiency. A handover algorithm called HoVe is presented. Based on various criteria for video distribution on ultra-dense 5G VANETs. The simulation results show HoVe’s efficiency in providing videos with 19% higher quality than state-of-the-art algorithms, improving the package delivery rate by at least 30%. This work studies a particular case of VANETs that benefits from computing at the edge of the network, the case of Connected Autonomous Vehicles, or CAVs. Edge and mist computing are emerging solutions for remote data processing for autonomous vehicles, offering greater computational power, as well as the low latency required by autonomous driving. This work proposes the MOSAIC algorithm for service migration and resource management for communication between layers and between layers in edge and fog computing. Simulation results show the efficiency of the proposed algorithm with a better performance of up to 50% in terms of latency and five times less migration failures.
Acesso aberto (Open Access)
A Multi-tier fog architecture for video on demand streaming
(Universidade Federal do Pará, 2018-03-05) SANTOS, Hugo Leonardo Melo dos; CERQUEIRA, Eduardo Coelho; http://lattes.cnpq.br/1028151705135221
Users are changing their traditional communication paradigm based on voice calls or text messages to real-time or on demand video services consumed on mobile devices. In this sense, the transmission of video content considering an adequate Quality of Experience (QoE) in mobile wireless networking infrastructures is a critical issue in both academic and industrial communities. Furthermore, video on demand have a growing consumption over Internet requiring higher bandwidth and lower latency. In this context, a fog computing paradigm can enhance the user experience in wireless networks. Fog computing for video on demand streaming can improve QoE by both video caching and adaptation schemes. However, it is important to evaluate the performance of downloading the videos with diferent codec con_guration and cached closer to the user to measure the gain from the user perspective. We designed a multi-tier fog computing architecture with three levels located in the cloud, nearer the edge and in mobile devices. We evaluated the performance of downloading the video from multiple tier located in distinct geographical with a multimedia application. We assessed in an experimental environment with idle and congested network of streamed videos coded into H.264 and H.265 with three bitrates in a scenario deployed in the FIBRE testbed. We collected QoE metrics, playback start time, freeze times, QoS metric, round-time trip, and energy consumption to analyze the gains for each video configuration. These results showed an important understanding about cache, codec and bitrate schemes in multimedia networking scenarios.
Acesso aberto (Open Access)
Otimização da alocação de recursos em datacenters hierarquicamente distribuídos
(Universidade Federal do Pará, 2018-12-19) VIEIRA, Rafael Fogarolli; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
The rapidly increasing volume of services and applications, in addition to the high wireless access demand, are significant challenges for the next generation of mobile networks. The growth in the volume of applications is the reflection of the quantity of “things” that are being connected to the network and generating a huge data traffic. A new paradigm that is gaining recognition in the field of wireless networks, and is also responsible for part of this growth in the volume of services and applications, is the Internet of Things. The high amount of data that is generated by connecting those devices to the network will require significant computational resources to be processed and stored. A prominent approach to handling such large amount of data is the use of Cloud Computing, which uses datacenters for storage and data processing. However, traditional Cloud Computing, which has centralized resources, is not able to handle the high volume of data and the strict latency and Quality of Service requirements. Thus, to address such adversities, a new emerging concept known as Edge Cloud Computing has been proposed as an extension of the traditional Cloud Computing, bringing computational resources to the edge of the network and thereby creating a hierarchy of datacenters. In this way, the stricter requirements from services and applications, such as obtaining near-instant user experience, can be satisfied. In this work, a mathematical formulation for the dimensioning and provisioning of a hierarchy of DCs is proposed. According to the obtained results, the hierarchy of DCs provisioned and dimensioned using the proposed model can be better when compared to the others, being able to allocate 99% of the set of applications that were used in the tests and to decrease the data flow in the backhaul links that is generated by the high number of applications the would circulate through the network. The analysis highlight the necessity of bringing computational resources to the network’s edge in addition to an efficient applications allocation strategy in order to guarantee a better network performance.
Acesso aberto (Open Access)
Otimização do tempo de teste funcional de placa de circuito impresso montada para computador pessoal
(Universidade Federal do Pará, 2012-01-13) OLIVEIRA, Edson Farias de; BLANCO, Claudio José Cavalcante; http://lattes.cnpq.br/8319326553139808
Increased competitiveness among the peer group has become increasingly important to the constant optimization of processes to consequently reduce manufacturing costs. The objective of this study is to assess the time involved in the functional testing phase of MBs produced in a company of the Industrial Pole of Manaus and propose improvements that lead to optimization of this phase. The actions taken with respect to optimizations led to the development system for capturing images to improve the analysis of downtimes and development of devices for testing, as well as the proprietary test system based on Linux to replace the previous system which relied of foreign partners. The percentage gains in the project was presented in four optimization proposals, the first being with the unification of the tests, the second with the test being performed on two board, the third with the replacement of the previous test by the system owner and end automation of the test device, which was demonstrated gains in each of the proposals. The results obtained after implementation of each proposal were positive and reinforce the need to apply scientific methods combined with creativity to achieve the optimization at any stage of the production process and closes the work suggesting ideas for future improvement of the system already optimized.
Acesso aberto (Open Access)
Otimização Energética em Redes B5G Utilizando RSMA.
(Universidade Federal do Pará, 2024-02-29) SANTOS, Albert Einstein Coutinho dos.; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734
Next-generation wireless communication networks demand extremely high requirements with the increase in data traffic, user transmission rates, decrease in minimum transmission delay, and a massive number of wireless devices per unit area. To meet these demands, network densification, the development of new access technologies, and resource management are necessary. However, challenges associated with interference and resource allocation emerge as significant obstacles. Power allocation is identified as crucial to mitigate interference, ensure specific quality requirements for different services, and enhance spectral efficiency. This work applies a multi-objective algorithm for power allocation in a scenario that employs the Rate Splitting Multiple Access (RSMA) concept, an emerging alternative for next-generation networks. RSMA involves splitting messages into private and common parts, allowing adaptation of the amount of signal sent in an overlapping channel. Evaluation metrics include spectral efficiency, specifically the minimum rate among users, the Sum Rate (SR), and energy efficiency. The average results obtained are compared with NOMA (Non-Orthogonal Multiple Access), indicating gains of 11% in spectral efficiency and 2% in energy efficiency with the implementation of RSMA in the simulated scenario.