Doutorado em Engenharia Elétrica
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- ItemOptimization approaches for enhanced operation and planning of distribution systems : a multi-objective perspective(Universidade Federal do Espírito Santo, 2025-02-25) Ferraz, Renato Santos Freire; Rueda Medina, Augusto César ; https://orcid.org/0000-0002-4291-3153; http://lattes.cnpq.br/7397584412509839; https://orcid.org/0000-0001-7571-1972; http://lattes.cnpq.br/1832936459743268; Fardin, Jussara Farias; https://orcid.org/0000-0003-4785-556X; http://lattes.cnpq.br/1912113095988528; Batista, Oureste Elias; http://orcid.org/0000-0003-4719-4132; http://lattes.cnpq.br/3717606765861586; Franco Baquero, John Fredy ; https://orcid.org/0000-0002-7191-012X; http://lattes.cnpq.br/8253028254016321; Donadel, Clainer Bravin ; https://orcid.org/0000-0002-3310-2762; http://lattes.cnpq.br/8624415630257203Efficient planning and operation strategies are essential for modern electric power networks to ensure cost-effective electricity delivery while maintaining reliable performance. However, the ongoing transformation of traditional centralized distribution systems, driven by the integration of distributed energy resources (DERs) and the growing adoption of electric vehicles (EVs), has introduced new and complex challenges for distribution system operators (DSOs). To address these issues, this thesis proposes multi-objective optimization approaches aimed at enhancing the planning and operation of distribution networks from the DSO’s perspective. The first approach focuses on the optimized allocation and sizing of DERs while ensuring recloser fuse coordination to preserve the original network protection scheme. The second approach handles the static network reconfiguration problem, incorporating the allocation and sizing of DERs and capacitors. The third approach extends this to dynamic network reconfiguration, considering DERs, capacitors, and electric vehicle charging stations. Finally, the fourth approach explores the dynamic network reconfiguration, capacitors allocation, and on-load tap changer adjustment, while accounting for stochastic customer-owned DERs. The main objectives are to minimize investment and operational costs, improve the system’s performance indicators–such as power losses and voltage deviation–and ensure the proper operation of the distribution system. Stochastic variations in DER generation, load profiles, and EV distribution throughout the day are modeled using the Monte Carlo Method. The multi-objective optimization problems are solved using the Non-dominated Sorting Genetic Algorithm II and the Multi-objective Cuckoo Search, with the final solution selected through the Fuzzy Decision-making Method. The results demonstrate significant improvements in the performance indicators of the distribution system, achieved while meeting all operational constraints
- ItemOtimização multiobjetivo para a alocação e dimensionamento de geradores distribuídos e estações de carregamento lento e rápido considerando programas de resposta à demanda(Universidade Federal do Espírito Santo, 2025-02-06) Ferraz, Rafael Santos Freire; Fardin, Jussara Farias ; https://orcid.org/0000-0003-4785-556X; http://lattes.cnpq.br/1912113095988528; Rueda Medina, Augusto César; https://orcid.org/0000-0002-4291-3153; http://lattes.cnpq.br/7397584412509839; https://orcid.org/0000-0001-8857-011X; http://lattes.cnpq.br/5323068276181437; Donadel, Clainer Bravin ; https://orcid.org/0000-0002-3310-2762; http://lattes.cnpq.br/8624415630257203; Antunes, Helio Marcos Andre ; https://orcid.org/0000-0001-8247-6448; http://lattes.cnpq.br/7601860538588447; Melo Trujillo, Joel David ; https://orcid.org/0000-0001-5046-1890; http://lattes.cnpq.br/4396532007704107; Encarnação, Lucas Frizera ; https://orcid.org/0000-0002-6162-7697; http://lattes.cnpq.br/5578918284508758The growing insertion of Electric Vehicles (EVs) and, consequently, a lack of planning in the installation of Electric Vehicle Charging Stations (EVCSs) can result in negative impacts on the electricity network. Therefore, the optimized allocation and sizing of EVCSs are important for reducing the costs of installing and operating the stations, in addition to the costs incurred by EV users for travel and recharging. Furthermore, the correct determination of slow and fast charging modes, combined with the adoption of demand response programs such as smart charging and Time of Use tariffs, are essential for reducing the aforementioned costs. These measures also contribute to the improvement of the voltage profile and the minimization of power losses in the distribution system. The purpose of this thesis is to conduct the optimized planning of public EVCSs, as well as the optimized allocation and sizing of Distributed Energy Resources (DERs), since DERs can play an important role in reducing the negative effects on the power grid caused by the large increase in EV demand. Therefore, this thesis includes four approaches using the proposed methodology. In the first approach, the methodology was tested in the IEEE 34-node test system, considering only the fast charging mode. In the second approach, only the slow charging mode was analyzed in the 33-node test system integrated with a 25-node traffic system. In the third approach, the planning of charging stations considered the integration of both fast and slow charging modes into the traffic systems interconnected with the distribution systems. Finally, in the fourth approach, in addition to this integration, the charging prices for both modes were treated as decision variables in the problem, also incorporating the perspective of the system operator. Additionally, a novel methodology was introduced for the spatiotemporal distribution of EVs over 24 hours based on closeness centrality from Graph Theory, considering commercial and residential areas in the studied systems. Different multi-objective algorithms were used to solve the presented problem, aiming to validate the methodology. It is important to highlight that the choice of the optimized solution was determined by graphical analysis or the Fuzzy Decision-Making Method. In all approaches, a significant reduction in the negative impacts of EV charging demand on the distribution system was observed, including power losses and voltage deviations. Furthermore, there was a decrease in recharging and travel costs for EV users, as well as a minimization of the costs for the system operator with the installation and operation of EVCSs and DERs
- ItemSilicon photonic integrated circuits as an enabling technology for passive optical network architectures(Universidade Federal do Espírito Santo, 2024-11-27) Marciano, Pablo Rafael Neves; Pontes, Maria José ; https://orcid.org/0000-0002-9009-2425; http://lattes.cnpq.br/4148956242627659; Segatto, Marcelo Eduardo Vieira ; https://orcid.org/0000-0003-4083-992X; http://lattes.cnpq.br/2379169013108798; https://orcid.org/0000-0001-8333-8012; http://lattes.cnpq.br/2070224436956646; Castellani, Carlos Eduardo Schmidt ; https://orcid.org/0000-0003-4154-5683; http://lattes.cnpq.br/1975160943820607; Rocha, Helder Roberto de Oliveira ; https://orcid.org/0000-0001-6215-664X; http://lattes.cnpq.br/8801325729735529; Nunes, Reginaldo Barbosa ; https://orcid.org/0000-0001-8877-1480; http://lattes.cnpq.br/0301147577506989; Conforti, Evandro ; https://orcid.org/0000-0002-4570-3725; http://lattes.cnpq.br/4808617538189330This work explored different PIC solutions, and their applications for optical networks were evaluated. Also, optical network techniques were applied to a new hybrid PON architecture focused on demonstrating the main characteristic that future networks must develop. There, a novel hybrid PON architecture associated with PIC was proposed for future generations of telecommunication systems. For instance, the PIC can implement optically complex functions traditionally implemented in the digital domain, allow future PON to implement an all-optical orthogonal frequency division multiplexing, and recover the data without using digital-signal processing devices. Also, the chromatic dispersion precompensation concept on the optical domain is exploited in this work, as we experimentally demonstrate the optical pre-equalization of OFDM-based optical IMDD systems in 125 km of optical fiber links through a photonic integrated circuit. The experiments with the PIC used OFDM signals with 5 GHz and 10 GHz with optical precompensation and without the traditional one-tap equalizer for simple optical OFDM systems. The results show significant enhancements in system performance and an improvement in power consumption. The capability of reducing latency is assured by reducing signal duration, which is a gold requirement for 5G New-Radio, PONs, and other networks
- ItemDevelopment of a neurofeedback system focusing on attentional state and validation based on source location and effective connectivity(Universidade Federal do Espírito Santo, 2024-10-28) Casagrande, Wagner Dias; Palacios, Ester Miyuki Nakamura ; https://orcid.org/0000-0002-2196-2490; http://lattes.cnpq.br/1236573205554833; Frizera Neto, Anselmo; https://orcid.org/0000-0002-0687-3967; http://lattes.cnpq.br/8928890008799265; https://orcid.org/0000-0002-1341-1509; http://lattes.cnpq.br/4132421149471418; Delisle Rodriguez, Denis; https://orcid.org/0000-0002-8937-031X; http://lattes.cnpq.br/7140331839822423; Mello, Ricardo Carminati de ; https://orcid.org/0000-0003-0420-4273; http://lattes.cnpq.br/1569638571582691; Ferreira, André ; https://orcid.org/; http://lattes.cnpq.br/5382777943593826; Lima, Eduardo Rocon de ; https://orcid.org/0000-0001-9618-2176; http://lattes.cnpq.br/6623746131086816This research addresses the development of a neurofeedback system to support the treatment of attention disorders through the recovery of compromised cognitive control, as well as the experimental validation of the system developed to improve the understanding of which brain regions are directly related to the state of attention and how connectivity occurs between them, which can serve as a guide for neurofeedback sessions applied to the treatment of attention disorders. The protocol defined in the neurofeedback sessions is related to theta and beta frequencies, as there is scientific evidence relating them to attention deficits. Electroencephalography data were collected during three neurofeedback sessions, where subjects played a serious game to stimulate attention, followed by data pre-processing, filtering, and classification. Initial validation was performed with 6 participants, followed by 40 additional participants for more robust results. To validate the neurofeedback system, a methodology was used to investigate source location and effective connectivity, comparing cortical activity between two groups (low and high difficulty — groups) differentiated by the difficulty level of the serious game. The inverse solution based on Cortical Current Density was applied to identify brain regions related to attentional state. From there, the effective connectivity between these regions was estimated using the Directed Transfer Function. With methods applied here, it was possible to identify that brain regions related to the state of attention, including both sides of the medial and dorsolateral prefrontal and right temporal region, showed a localized higher beta activity and interconnectivity in subjects performing greater demanding task (high-difficulty group). This pattern was not observed in subjects performing lower demanding task (low-difficulty group), which showed more dispersed flows. In addition, Statistical validation was conducted using ANOVA and analysis of the theta/beta ratio distribution between the two groups. Among the results found, a one-way repeated measures ANOVA demonstrated that when comparing the theta/beta ratios between the three study sessions (S1 vs. S2 vs. S3), for the high difficulty group, the regions that presented significant differences were: right dorsolateral prefrontal (F(2.57) = 3.158, F = 3.225) and left temporal (F(2.57) = 3.158, F = 3.731), demonstrating that the game’s difficulty level influences the theta/beta ratio of the mentioned regions. Future work proposes the development and application of a virtual reality environment to further investigate brain responses to attentional stimuli, in addition to promoting greater participant engagement. It is also proposed to apply the developed system to participants with attention deficits, aiming to improve treatment methods
- ItemA socially assistive robot as a therapeutic tool for applied behavior analysis therapy in children with autism spectrum disorder through dynamically modulated serious games(Universidade Federal do Espírito Santo, 2024-10-07) Freitas, Éberte Valter da Silva; Bastos Filho, Teodiano Freire; https://orcid.org/0000-0002-1185-2773; Caldeira, Eliete Maria; Cuadros, Marco Antonio de Souza Leite; Valadão, Carlos Torturella; Vasquez, Luiz Fernando GuerreroThis work presents the programming/adaptation of the Socially Assistive Robot (SAR) called Mobile Autonomous Robot for Interaction with Autistics and Trisomy 21 (MARIA T21) to be able to carry out interventions, according to the Applied Behavior Analysis (ABA) therapy, applied to Children with Autism Spectrum Disorder (ASD), Serious Games (SGs), which are projected by MARIA T21, with difficulty modulation dynamics, are used as part of this therapy thus creating a motivating and facilitating effect for children and therapists. The SGs were developed in Unity 3D, using C Sharp language (C#), and modulated according to the child’s performance, eye attention level, and user’s facial emotion, being integrated into the robot through the Robot Operating System (ROS). The child-Robot Interaction (CRI) protocol followed in this research was carried out in a child’s psychotherapy room at the APAE (Association of Parents and Friends of Excepcional People for the acronym in Portuguese) of Vitoria in Espirito Santo state (Brazil), which was instrumented with four video cameras and supervised by a group of researchers. The sample consisted of 18 children with a conclusive diagnosis of ASD, 3 girls and 15 boys, aged 5 to 9 years and presence of stereotyped movements of eyes and/or hands and/or feet. The experiments were separated into three modules for which SGs or specific therapeutic dynamics were applied, namely: Cognitive Module, Physical Module and Functional Module. The first one brings together the games and dynamics applied by MARIA T21 focused on the development and improvement of cognitive learning skills, whereas the physical module brings SGs for motor evaluation and correction, that can be used for physical and postural strengthening by a physiotherapist. Finally, the functional module has applications of SGs and Occupational Therapy dynamics in order to work on the so-called Activities of Daily Living (ADLs) and encourage autonomy in those assisted. In addition to the data recorded by MARIA T21, two evaluation scales– Pediatric Evaluation of Disability Inventory Computer Adaptive Test (PEDI-CAT) and System Usability Scale (SUS)– were applied for each module, and another for the degree of acceptance of the robot in therapy by the child. The results obtained so far enable the use MARIA T21 as an ABA therapeutic tool. In addition, the SGs are capable of dynamically modulating their difficulty, providing greater user adherence and continued attention in the optimal learning zone of the ABA bibliography while carrying out the activities. The technology embedded in the robot has also enabled the identification and quantification of characteristics and parameters, such as the presence and recurrence of stereotypies and postural dysregulations, placing the robot as an innovative and promising tool to assist health professionals in the early diagnosis, conduction and follow-up of therapies.