Teses em Engenharia Elétrica (Doutorado) - PPGEE/ITEC
URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2317
O Doutorado Acadêmico inicio-se em 1998 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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Item Acesso aberto (Open Access) Modelagem da perda de qualidade de videos H.264 em redes sem fio considerando perdas de PSNR e de frames(Universidade Federal do Pará, 2019-08-16) CARMONA, João Victor Costa; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609Multimedia applications have been growing in recent years; new consumptions like online games, video conference, video on demand and IP telephony are some of these. However, there is a greater prominence in the search related to videos and streaming, currently in high resolutions and mostly traffic over wireless networks, mainly due to the proliferation of mobile devices and significant increase of access networks, which make it more comfortable. Providing this information is easy. Thus, as an immediate consequence of this type of flow, there is a need for investments in techniques and mechanisms that provide the end user with the desired quality and satisfaction in the face of high definition content. This work aims to perform the modeling of video quality loss by analyzing their performance in various resolutions, specifically standards in HD and UHD, at 720p, 1080p and 2160p. In this sense, applying a correlation investigation between the metrics extracted from the videos, using Pearson’s correlation coefficient, and fundamentals of the area in question. Also proposing equations for quality loss modeling, based on analysis of metrics associated with packet loss, in which at the end of the study and according to notes made throughout the text, we used for the general modeling equation, the parameters of Loss of PSNR and Loss of Total Frames. The result obtained shows maximum values of RMSE and Standard Deviation of 0.793 dB and 0.810 dB, respectively, making the developed model very good for the tested video set and its resolutions.Item Acesso aberto (Open Access) Orquestração de recursos multicamadas para arquiteturas de próxima geração(Universidade Federal do Pará, 2024-11-29) PAIXÃO, Ermínio Augusto Ramos da; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734Due to the significant increase in data traffic and the large number of devices using Internet Protocol (IP), operators and researchers are seeking solutions to meet the growing demand. One of the most attractive solutions is Heterogeneous Cloud Radio Access Networks (H-CRAN), which has the capability to address current generation problems and bring various improvements, such as centralized processing and greater energy efficiency. The central challenge lies in the complexity of managing and optimizing these resources efficiently, especially in highdemand scenarios with dense device populations. However, the orchestration of resources such as radio, mapping between radio and BaseBand Unit (BBU), and load balancing in the BBU pool remains critically important. This thesis presents a framework aimed at reconfiguring the mobile network in areas affected by the variability of tidal effect traffic, ensuring high availability, energy savings, and improved data processing efficiency. The results obtained were compared with other approaches in the literature and demonstrated that the proposed framework optimizes the resources of the Peak Remote Radio Head (PRRH) and the BBU without compromising the user’s minimum QoS. The findings highlight a reduction of up to 9% in the number of active antennas over a 24-hour period and emphasize that the proposed solution consumes up to 14% less energy than the primary reference in this thesis.Item Acesso aberto (Open Access) Scalable AP selection strategies for user-centric cell-free massive MIMO networks(Universidade Federal do Pará, 2024-06-06) FREITAS, Marx Miguel Miranda de; COSTA, Daniel Benevides da; http://lattes.cnpq.br/0644241968356756; https://orcid.org/0000-0002-5439-7475; VALCARENGHI, Luca; COSTA, João Crisóstomo Weyl Albuquerque; http://lattes.cnpq.br/9622051867672434User-centric (UC) cell-free (CF) massive multiple-input multiple-output (MIMO) systems are promising technologies for beyond 5G (B5G) networks. In these systems, the user equipment (UE) is associated with a subset of access points (APs) distributed into the coverage area, leading to improvements in macro-diversity and spectral efficiency (SE) compared to conventional cell-based systems. Despite the benefits, challenges such as scalable AP selection strategies, computational complexity (CC), and inter-central processing unit (CPU) coordination may still exist in these systems. In this regard, this thesis proposes a novel and general AP selection framework that affords scalability for UC systems, enabling more efficient use of the network resources, such as transmission power and reduced processing demands. The solution is based on a matched-decision among the most suitable connections for APs and UEs. Moreover, three strategies to fine-tune the AP clusters of UEs are proposed, aiming to reduce the number of APs connected to each UE without compromising the SE. Simulation results reveal that the matched-decision framework improves up to 163% the SE of the 95% likely UEs compared with baseline schemes. A heuristic approach that reduces the effects of inter-CPU coordination is also proposed. It decreases the number of inter-coordinated UEs (i.e., UEs connected to multiple CPUs) on each CPU to reduce signaling demands on backhaul links. Numerical results indicate that the proposed method mitigates inter-CPU coordination while yielding slight degradation in SE and improving energy efficiency (EE). Finally, this thesis investigates the performance of UC systems with limited processing capacity. Specifically, it is assumed that the CC of performing channel estimation and precoding signals does not increase with the number of APs. Thus, the UE can only be associated with a finite number of APs. Furthermore, a method is proposed for adjusting the AP clusters according to the network implementation, i.e., centralized or distributed. The results show that UC systems can keep the SE under minor degradation even if the CC up to 96%. Besides, the proposed method for adjusting the AP cluster leads to further reductions in CC.Item Acesso aberto (Open Access) Smartcom: uma arquitetura inteligente de gerenciamento de consumo de energia para smart home(Universidade Federal do Pará, 2017-08-25) OLIVEIRA, Edvar da Luz; FRANCÊS, Carlos Renato Lisboa; http://lattes.cnpq.br/7458287841862567With advances in information technology for a variety of areas, such as health and wellness, Smart Home based solutions using Internet of Things (IoT) technologies are gaining in popularity, including energy-saving alternatives based on Home Energy Management Systems (HEMS). This thesis defines an innovative architecture, called SmartCoM, which is implemented to monitor and manage residences using IoT technologies. Such a strategy involves defining the parameters that can affect the interoperability between measurement, management and the layers of data communication, which are the resources necessary for the hardware devices to perform the intended monitoring and measurement. In addition, an interface is defined by a middleware layer to integrate the management of external installations and the visualization of data through cloud services. The SmartCoM architecture is defined end-to-end in detail from the consumer's point of view and optimization strategies are employed for both the end customer and the utility. In order to evaluate the proposed architecture, a case study was elaborated, from which the viability of developing solutions for Smart Home according to the requirements described in SmartCoM is observed.Item Acesso aberto (Open Access) SmartLVEnergy: um framework para gestão energética inteligente e descentralizada de sistemas legados de baixa tensão(Universidade Federal do Pará, 2024-07-11) FERNANDES, Rubens de Andrade; GOMES, Raimundo Cláudio Souza; http://lattes.cnpq.br/4244097441063312; COSTA JÚNIOR, Carlos Tavares da; http://lattes.cnpq.br/6328549183075122Essential for technological and economic progress, electrical energy requires well-founded solutions and strategies for efficient and sustainable management. Existing consumer units, lacking modern technological resources, need gradual alternatives to optimize energy use, making the most of pre-established resources. In this context, retrofit offers an effective update for these infrastructures. Systematic models and strategies can standardize and ensure the replication of these solutions in different contexts through abstractions known as frameworks. However, there is a lack of frameworks to enable the implementation of systematic retrofit strategies for energy management, especially in the low-voltage energy sector. To fill this gap, this thesis presents the SmartLVEnergy framework, proposed to guide the design of innovative retrofit strategies to modernize legacy low-voltage installations with IoT, AIoT, and distributed computing solutions, optimizing energy management with distributed technological resources and advanced predictive capabilities. The experiments conducted in this thesis are presented in the format of aggregated scientific articles, which contributed to the conception of the SmartLVEnergy framework. As a result, it was possible to implement energy management tools in existing building and industrial scenarios in a systematic manner, based on the premises of the proposed framework. The main focus was the analysis and prediction of the energy demand of the installations and their respective circuits, allowing to anticipate and mitigate demand overrun events of the consumer units, following the guidelines of the Brazilian National Electric Energy Agency. The strategies conceived included the development, use, and integration of sensing, communication, and computing resources, distributed locally, in the cloud, and at the edge, according to the principles of the SmartLVEnergy framework, maximizing the use of existing resources according to the specific needs of each installation. The proposed framework is flexible and allows the integration, expandability, and interoperability of technological solutions across legacy systems, enabling operations according to the peculiarities and resources of each pre-existing context. This versatility confirms the relevance of this work as a robust and sustainable proposal to promote energy efficiency today, especially in legacy low-voltage systems.