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Disertaciones |
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1
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Rodrigo Bonifácio de Medeiros
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Design of a Fuzzy PID controller in embedded hardware for a lower limb exoskeleton
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Líder : DANIEL MAURICIO MUNOZ ARBOLEDA
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MIEMBROS DE LA BANCA :
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ABEL GUILHERMINO DA SILVA FILHO
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DANIEL MAURICIO MUNOZ ARBOLEDA
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GUILLERMO ALVAREZ BESTARD
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RENATO CORAL SAMPAIO
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Data: 30-ene-2023
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Resumen Espectáculo
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Robotic manipulators are multiple input/output (MIMO) systems with multiple points of nonlinearities affected by numerous uncertainties and disturbances. PID controllers are widely used in industry for kinematic and dynamic control. However, when applied to MIMO systems, it is not easy to tune them and achieve performance improvements. In this work, a standard PID controller is combined with a fuzzy precompensator (FP-PID), both of which are tuned using the PSO mono-objective algorithm and the multi-objective algorithms NSGA-II and MODE for a two-degree-of-freedom (2-DOF) robotic manipulator, representing an exoskeleton. To validate the system, two sets of real human gait data were used: normal walking and stair climbing to estimate the error trajectory of the manipulator. The statistical analyzes of the algorithms with 16 experiments were satisfactory, and the addition of the fuzzy precompensator to the conventional PID resulted in a reduction of the mean square error of one of the links of the manipulator by up to 73 percent, apart from improving the smoothing of the torque with the multi-objective results. Another focus is the development of a hardware-software co-project for the FP-PID model of the exoskeleton, embedding the system on an ARM processor for the PID and system plant of the robotic manipulator and an FPGA architecture for the fuzzy controller module. The result shows that the control loop keeps the response time within the expected range of the application.
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2
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Leonardo Bezerra Libanio
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PID CONTROLLER TUNING APPLIED TO A MOTOR-GENERATOR SET USING BIOINSPIRED ALGORITHMS
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Líder : DANIEL MAURICIO MUNOZ ARBOLEDA
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MIEMBROS DE LA BANCA :
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CARLOS HUMBERTO LLANOS QUINTERO
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DANIEL MAURICIO MUNOZ ARBOLEDA
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MAURICIO FIGUEIREDO DE OLIVEIRA
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RUDI HENRI VAN ELS
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Data: 13-feb-2023
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Resumen Espectáculo
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The present work presents the development of a proportional integral derivative (PID) tuning for a motor generator set using bioinspired algorithms, and proposes an alternative to meet the tuning in offshore environments. The tuning of the controller was carried out from the formulation of an optimization problem, whose performance analysis is done by tracking the trajectory of the response in time domain, applying disturbances when increasing and decreasing loads in the power system, thus providing the necessary data to optimize the system and raise the mechanical potential, reducing instabilities and maintenance and increasing the energy efficiency. A preliminary analysis of the components and variables involved in the motor-generator system is presented, namely: internal combustion engine, electric generator, controller and data acquisition system. A simplified non-linear modeling was made, from a transfer function of a servo system. The obtained model was used to extract a set of controller performance parameters that guide the search process of particle swarm optimization (PSO) and differential evolution (DE) algorithms, as well as their variations, using Matlab/Simulink. For comparative purposes, the PIDTune function was used, allowing the evaluation of the performance of bioinspired algorithms. With the obtained PID parameters, project simulations and discussions were carried out. Subsequently, the PID parameters were implemented in the controller, following trajectory tracking tests with a Wartsila engine, coupled to a Leroy Somer electric generator from the Petrobras platform 65 offshore installation. Finally, a discussion is made about the effectiveness of the proposed optimization of the controller with the selected tuning and an analysis of the engine-generator set parameters is presented, as well as conclusions and suggestions for further research.
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3
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Carlos Alberto Alvares Rocha
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Deep Learning Applied to Long Text Classification with Few Data: The Case of PPF
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Líder : LI WEIGANG
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MIEMBROS DE LA BANCA :
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LI WEIGANG
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DANIEL MAURICIO MUNOZ ARBOLEDA
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VICTOR RAFAEL REZENDE CELESTINO
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MARCELO XAVIER GUTERRES
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Data: 16-mar-2023
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Resumen Espectáculo
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Natural language processing (NLP) is an area of artificial intelligence that has been gaining a lot of attention in recent years. The great recent advances attracted the attention of the Ministry of Science, Technology and Innovations (MCTI) to the execution of a project with the objective of locating international funding for research and development accessible to Brazilian researchers. Classification appears as a challenge for this solution due to the absence of high quality labeled data, which are requirements for most state-of-the-art implementations in the field. This work explores different machine learning strategies to classify long, unstructured and irregular texts, obtained by scraping websites of funding institutions, to, through an incremental approach, find a suitable method with good performance. Due to the limited amount of data available for supervised training, pre-training solutions were employed to learn the context of words from other datasets, with great similarity and larger size. Then, using the acquired information, a transfer of learning associated with deep learning models was applied to improve the understanding of each sentence. To reduce the impact of text irregularity, pre-processing experiments were carried out to identify the best techniques to be used for this type of content. Compared to the baseline of the work, it was possible to reach a new level of results, exceeding 90% accuracy in most of the trained models. The Longformer + CNN models stand out, which reached 94% accuracy with 100% accuracy and the Word2Vec + CNN model with 93.55% accuracy. The study's findings represent a successful application of artificial intelligence in public administration.
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4
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ANDREA HENRIQUE CAMPOS DA FONSECA
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Case Study: Application of Information Systems and Insertion of Mechatronic Products in Improving SUS User Service and Combating COVID-19
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Líder : SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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MIEMBROS DE LA BANCA :
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SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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ANTONIO PIRATELLI FILHO
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EUGENIO LIBORIO FEITOSA FORTALEZA
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Paulo Roberto dos Santos
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Data: 02-jun-2023
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Resumen Espectáculo
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In Brazil, the information systems aimed at meeting social demands such as public health services have had a more concerned look at the global health crisis - COVID-19- that we are facing, but there are still limitations in the field of information technology in public health services, primary care, verification of scheduled exams, consultations, and care in vaccine rooms. This chapter will deal with the Research and Innovation Project, the 3TS that comprises the SUS+ modules, which is the possibility of self-service to the patient, and the Imuna SUS that shows the control of received vaccines. This set of Technology and Communication Systems (TIC) has steps that go from the original conception of the information system to its arrival at SUS, adding value to the services provided by SUS
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5
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Elpídio Cândido de Araújo Bisneto
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Simultaneous Wireless Information and Power Transfer for Sensor Networks
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Líder : DANIEL MAURICIO MUNOZ ARBOLEDA
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MIEMBROS DE LA BANCA :
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OLYMPIO LUCCHINI COUTINHO
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DANIEL COSTA ARAUJO
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DANIEL MAURICIO MUNOZ ARBOLEDA
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LEONARDO AGUAYO
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Data: 14-jun-2023
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Resumen Espectáculo
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The Simultaneous Wireless Information and Power Transfer (SWIPT) technology has emerged as a promising solution for simultaneous stable data and power transmission. SWIPT uses radio frequency (RF) signals to transport both data and energy, making it an attractive option for applications in challenging environments such as unmanned aerial vehicles (UAVs) and smart agriculture.
However, SWIPT faces obstacles such as efficient long-distance power transmission and power constraints in the ISM frequency range. Additionally, a balance needs to be struck between data and energy transmission, considering energy consumption and robustness in data transmission and reception.
In this context, this work aims to develop a SWIPT circuit based on Amplitude Shift Keying (ASK) modulation coupled with a Dual-Polarized (DP) architecture. Aspects such as energy harvesting efficiency, data transmission rate, and the trade-off between the two are considered. Furthermore, an optimization in the antenna array is proposed using bio-inspired algorithms to reduce side lobes.
The obtained results show an RF-DC converter efficiency of 78.94% for 17 dBm, a data transmission rate of 7 kbps with a bit error rate (BER) of 10E-3 for a signal-to-noise ratio (SNR) of 13 dB. The antenna array achieved a gain of 12.55 dBi in the vertical polarization and an average gain of 7.16 dBi in the horizontal polarization.
Experimental data demonstrates that the proposed system is a viable SWIPT receiver for various monitoring applications using wireless sensor networks. The solution achieved good energy efficiency and the ability to receive high input powers. The antenna array allows for simultaneous data and energy transmission while ensuring isolation between the systems. This work highlights the Dual-Polarized architecture as promising, with potential optimizations and improvements in future works.
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6
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Rafael Pissinati de Souza
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DEVELOPMENT OF A MEDICAL ASSISTIVE EQUIPMENT CAPABLE OF IMPROVING POWER CONTROL THROUGH FREQUENCY VARIATION WITH COMPLEX BIOIMPEDANCE FEEDBACK
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Líder : SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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MIEMBROS DE LA BANCA :
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DANIEL MAURICIO MUNOZ ARBOLEDA
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ICARO DOS SANTOS
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Paulo Roberto dos Santos
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SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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Data: 18-jul-2023
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Resumen Espectáculo
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Problem: Despite the great advances in modeling in radiofrequency ablation, a great difficulty is due to the intrinsic characteristics of human body tissues. Variations in the amount of water and fat in the body composition of patients generate significant variations between the models and the results obtained in the ablations.
Objective: To develop a generalist radiofrequency ablation equipment, capable of performing complex bioimpedance reading and adjusting the frequency and amplitude of the wave, to improve impedance matching and increase the efficiency of the ablation process.
Methodology: The development was based on the circuit of the equipment that was already under development, but all circuits were analyzed, simulated and some were designed. The equipment has a main source, with a voltage regulator circuit for 5 and 12V dc (Volts in direct current), has a variable Buck converter, which is responsible for feeding the power circuit, a Push-Pull circuit to generate the alternating signal, current and voltage measurement circuits, in addition to the phase shift measurement circuit, so that it can determine the complex impedance of the tissue. To validate the operation of the equipment, we performed ablation in porcine and bovine liver tissue with power variation.
Results: The ablation performed in bovine liver presented a curve relating the variation of power with the ablation area, showing that there is an optimal time for ablation with constant power to be achieved. The tests on porcine liver showed constancy in the ablation area, even though the tests were performed in different sectors. It was also possible to determine that the implementation of a control is able to significantly increase the ablation area.
Conclusion: The equipment was able to receive voltage and frequency control techniques to maximize power transfer and increase the ablation area. Due to the ability of the equipment to communicate via wi-fi, there is the possibility to implement complex control systems without compromising the local processing of the equipment.
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7
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KLÉRISTON SILVA SANTOS
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ARFACTA - PROJECT FOR THE DEVELOPMENT AND IMPLEMENTATION OF A SIMULATION-BASED TUMOR ABLATION DEVICE WITH EX VIVO TESTING
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Líder : SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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MIEMBROS DE LA BANCA :
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DANIEL MAURICIO MUNOZ ARBOLEDA
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ICARO DOS SANTOS
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Paulo Roberto dos Santos
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SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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Data: 01-ago-2023
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Resumen Espectáculo
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Radiofrequency Ablation (RFA) is a minimally invasive and effective procedure to treat Hepatocellular Carcinomas (HCC). During the procedure, an electrode is inserted into the affected area of the liver and radiofrequency generates intense heat at the tip of the electrode. This heat can destroy the tumor, leading to necrosis of the affected region. A RFA has been widely used as an established technology in the medical field for the efficient treatment of HCC, offering advantages such as reduced hospital stays and post-surgical complications. The RFA procedure has some limitations, including inadequate response for tumors larger than 3 cm, lack of customization of energy application protocols for each patient, low standardization inherent to the generating equipment used in the procedures, and lack of standardization in the description of the dynamic behavior of the tissue during RFA. Thus, the following paper consists in determining parameters that subsidize the approach of a new hardware capable of solving these gaps. A new hardware was developed based on current market standards, capable of being widely adjustable and dynamic, providing satisfactory control conditions with reliability in the power circuit part. During the development of the work, several aspects were considered, including understanding the behavior of the output signal demand, control of the push-pull circuit through the duty cycle, power supply through the DC-DC regulators, among others. The physical effects of radiofrequency on the liver were also studied. Electrical circuit simulations were performed to analyze the influence of the energy demand of each block of the RFA circuit, with the purpose of ensuring the reliability of the signals demanded by the electronic components in the new equipment. These simulations allowed a better understanding of the circuit behavior and, saving time and material resources, which helped in the proposition of a more efficient and precise design for the RFA. To prove the simulated data, a prototype was suggested and assembled, enabling its use in tests and data collection with porcine liver ex vivo.
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8
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Pedro Aurelio Coelho de Almeida
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Unsupervised learning model based on visual saliency for automatic segmentation of the lung region in X-ray images
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Líder : DIBIO LEANDRO BORGES
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MIEMBROS DE LA BANCA :
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DIBIO LEANDRO BORGES
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HELIO PEDRINI
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SANDERSON CESAR MACEDO BARBALHO
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SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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Data: 25-ago-2023
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Resumen Espectáculo
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Automatically dividing an image into regions of similar properties, named segmentation, is a challenging task for computers, and it can avoid human errors induced by fatigue. One area that may be greatly benefited from automatic segmentation methods is medical imaging analysis. Within it, chest X-rays are amongst the cheapest and most widely available type of medical images. Provided they can be used for diagnosing lung related diseases, they are an excellent target for automatic image segmentation methods. The current state-of-the art image segmentation relies on manual labels defined a priori to ’learn’ the necessary features for this task. Deep unsupervised learning stands as an interesting alternative to supervised methods, since it only requires the input (e.g. the image X-ray) for training. Due to the visual nature of image segmentation and the standout aspect of the lungs on an X-ray, the combination of unsupervised learning and visual saliency (i.e. the attempt to model human visual attention) is tested for the lung segmentation on X-ray images. The saliency method is compared to state-of-the-art supervised and unsupervised models designed for grayscale medical image segmentation. Results using the Dice, jaccard, precision and recall scores on JSRT and MC datasets indicate that the saliency method enhanced performance over other unsupervised approaches is statistically significant. When compared to supervised models, the saliency method appears to adequately substitute them given the flexibility achieved by the independence from manual labels. Future work includes segmenting the cardiac area and identifying anomalies on X-ray images in an unsupervised fashion.
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9
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MARIANNYS RODRIGUEZ GASCA
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ANALYSIS OF THE IMPACT OF TEAM SENIORITY ON COLLABORATIVE WORK PERFORMANCE: CASE STUDY OF A MECHANICAL LUNG VENTILATOR DEVELOPMENT TEAM
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Líder : SANDERSON CESAR MACEDO BARBALHO
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MIEMBROS DE LA BANCA :
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SANDERSON CESAR MACEDO BARBALHO
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CARLOS HUMBERTO LLANOS QUINTERO
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LUIS ANTONIO PASQUETTI
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MARLY MONTEIRO DE CARVALHO
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Data: 28-ago-2023
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Resumen Espectáculo
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Mechatronics is a field in constant evolution, driven by advanced technologies, which combines precision mechanical engineering, electronic control and systems thinking to design products and manufacturing processes. This approach is applied in various areas, such as medicine, industry, automation and control systems. In this sense, the work in an interdisciplinary team is fundamental to guarantee the integration of these disciplines and, therefore, a high performance of the two mechatronic products. Therefore, the characteristics of the composition of the equipment are essential to optimize this process. In this context, this research proposed to evaluate a work performance framework in virtual product development teams mediated by a seniority relationship (education and practical development experience). For this framework, it was based on the input-process-output factor structure. Furthermore, the research analyzes a case study to evaluate how two different seniority profiles of two members performed during the project and how this impacted the results of the project. The results will show interesting trends with respect to the positive influence of the senior profile with respect to the interactions and performance of the input-process-output factors, with special emphasis on strengthening the two processes throughout the project. As for the junior profile members, they will allow us to observe that they will face greater challenges and therefore a lower performance in their performance in the project.
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10
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TIAGO MARTINS DE BRITO
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DEVELOPMENT OF A RADIOFREQUENCY ABLATION SYSTEM FOR CHARACTERIZING THE ROLL-OFF CURVE IN HEPATIC, PULMONARY, AND CARDIAC TISSUES
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Líder : SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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MIEMBROS DE LA BANCA :
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SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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ANTONIO PIRATELLI FILHO
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ADSON FERREIRA DA ROCHA
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ALLISSON LOPES DE OLIVEIRA
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Data: 07-nov-2023
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Resumen Espectáculo
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In this master's study, we address the complexities and implications of cancer, an intricate disease with a significant impact on global health. Our focus is directed towards three critical medical conditions: liver cancer, lung cancer, and cardiac arrhythmia. The core of this project lies in the development of ARFACTA, an innovative biomedical device that utilizes radiofrequency ablation as a treatment. Additionally, we investigate the characterization of roll-off curves in post-mortem bovine and porcine tissue maintained in an ex-vivo state. This research meets the growing demand for affordable treatments within the Unified Health System (SUS), based on data that highlight the costliness of import alternatives. The primary goal is to improve the quality of life for patients, reduce the costs associated with treatment, and alleviate the strain on healthcare systems, both public and private.
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11
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Angélica Kathariny de Oliveira Alves
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Bond Graph modelling of the biophysical characteristics of liver tissue applied to the control of the radiofrequency ablation procedure
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Líder : SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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MIEMBROS DE LA BANCA :
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SUELIA DE SIQUEIRA RODRIGUES FLEURY ROSA
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ADSON FERREIRA DA ROCHA
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ALLISSON LOPES DE OLIVEIRA
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FÁTIMA MRUÉ
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Data: 09-nov-2023
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Resumen Espectáculo
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In this study, the challenge of treating Hepatocellular Carcinoma (HCC), a fatal liver cancer, is addressed. Recognising the limitations of radiofrequency ablation (RFA) due to biophysical variations in HCC-related liver tissue, the main objective is to develop an adapted Cole-Cole model using the Bond Graph (BG) modelling technique. This adaptation will incorporate the complex characteristics of liver tissue affected by HCC, including variations associated with liver cirrhosis, fat and blood vessels. The expected contributions of this study include improved understanding of the interaction between ARF and the target tissue, enabling detailed analyses of the system’s stability and efficacy of the system, potentially resulting in significant advances in treatment strategies for HCC patients, as well as providing a solid foundation for future multidisciplinary future multidisciplinary research.
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12
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Yasmin Yunes Salles Gaudard
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Using Model-Based Systems Engineering to implement Digital Twins in Manufacturing Systems.
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Líder : JONES YUDI MORI ALVES DA SILVA
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MIEMBROS DE LA BANCA :
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ANDREA CRISTINA DOS SANTOS
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JONES YUDI MORI ALVES DA SILVA
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REGIS KOVACS SCALICE
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SANDERSON CESAR MACEDO BARBALHO
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Data: 15-dic-2023
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Resumen Espectáculo
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Historically, each Industrial Revolution emerged supported by technologies that increased efficiency and reduced costs. Industry 4.0, acclaimed by many as the 4th Industrial Revolution, is supported by a set of Enabling Technologies, such as Big data, Robotics, Artificial Intelligence, Cloud Computing, Additive Manufacturing, Internet of Things, and Virtual/Augmented Reality, among others. When associating these technologies, there is a convergence to the Cyber-Physical Systems concept, and one of its implementations is the Digital Twin (DT). A DT is commonly defined as a virtual representation of a physical object or process, allowing ultra-realistic simulations of physical models, capturing historical data, and real-time processing/monitoring. Different levels of abstraction and detail offer varied views of industrial systems, equipment, processes, and products. Given its complexity and multi-technological composition, its implementation is not smooth. In this context, we propose using a methodology based on Model-Based Systems Engineering (MBSE) to support a model industry's technological evolution, aiming to implement its DT. Our model industry is an innovation laboratory comprising several sectors: Management, Design Office, Manufacturing (several processes), Stock, and Maintenance, among others. In this work, we focus on the area of Additive Manufacturing for external customers (private companies) and internal ones (academic projects), providing the modelling of the optimal path from the arrival of a work order to 3D printing and final delivery of parts. Using the Reference Architecture Model for Industry 4.0 (RAMI-4.0) and the ISO Digital Twin Framework for Manufacturing (ISO-2347), we modelled the system at several levels with the MBSE Arcadia method through the free tool Capella. As a result, we reached the Final System Architecture, indicating the actors involved in the scenario, their functionalities and the interaction flow among all the components. This model allows the simulation and analysis in a single framework considering the complete system and not only isolated subsystems. It provides us with correlations among indicators of different abstraction levels, generating the basis for implementing a multi-scope DT. We can highlight that MBSE systems, even supported by formal methods of Systems Engineering, still cannot be considered mature enough. Consequently, its tools constantly evolve, and new applications favour its consolidation. Therefore, the principles used to construct this work result in an innovative methodology by allying MBSE's tooling support to implement Digital Twins for Manufacturing Systems efficiently.
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Tesis |
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1
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Bruna Felippes Corrêa
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PROPOSAL OF THE CUBE-4.0 READINESS MODEL FOR ENGINEERING COMPANIES THROUGH DIGITAL TRANSFORMATION CONTEXT
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Líder : SANDERSON CESAR MACEDO BARBALHO
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MIEMBROS DE LA BANCA :
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CARLOS HUMBERTO LLANOS QUINTERO
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INA HEINE
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JONES YUDI MORI ALVES DA SILVA
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MARIA ELIZETE KUNKEL
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SANDERSON CESAR MACEDO BARBALHO
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Data: 16-ene-2023
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Resumen Espectáculo
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This thesis proposes a new Readiness Model, called CUBE-4.0, to assess the current state of readiness and guide improvement strategies, in an innovative way, in engineering companies (industries) of any size, type, and level of readiness, in the digital transformation context. A systematic literature and theory review was conducted to select, with a Bibliographic Synonym Test (BST) and a specific 8-Step Search Flow (both created by the author), concrete information from 486 relevant studies found in 10 renowned databases, considering 63 existing maturity and readiness models and the entire scientific literature on this subject worldwide. Based on the existing maturity and readiness models’ shortcomings and after pre-design and systematization, the CUBE-4.0 Readiness Model was developed as an essential contribution to this research stream. This includes its Framework (dimensions, sub-dimensions, elements, readiness levels, radar chart, score calculation and data collection methodology), Questionnaire and Roadmap. Besides, this model provides a practical and easily applicable methodology, with 3 dimensions (X = Organizational Enabler, Y = Technological Enabler, and Z = Processes Maturity Enabler), 6 sub-dimensions, and 21 elements. Furthermore, it has a scale from 0 to 5 to assess the company readiness level, defined and structured in an unprecedented way, besides considering, for the first time, maturity as an "input" enabler for the company readiness evaluation, and not as an "output" as in all other existing models. Also, a "CUBE-4.0 Questionnaire" was developed, based on these CUBE-4.0 concepts, to collect data and survey engineering firms about their readiness for digital transformation. Finally, with a "CUBE-4.0 Roadmap", based on the CUBE-4.0 Questionnaire results, this model can also help corporate boards to guide strategies and plan improvements in their companies in this Industrial 4.0 (I4.0) Age. After presenting some deductive hypotheses, a pre-test with the CUBE-4.0 Questionnaire and CUBE-4.0 Roadmap was applied in six steps, whose satisfactory results will be presented in this thesis. Then, the CUBE-4.0 Model was reviewed and applied in three renowned engineering companies, enabling its complete validation, by using theoretical and practical methods. Last, this thesis will present the main discussion about the results. This includes the falsiability of the hypotheses, concluding that CUBE-4.0 Model is complete, useful, inexpensive, and efficient, and could help companies to improve their readiness through the digital transformation context.
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2
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Maria de Fátima Kallynna Bezerra Couras
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Coupled Nested Tensor Decomposition applied to Dual-Polarized MIMO Communication Systems
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Líder : JOAO PAULO JAVIDI DA COSTA
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MIEMBROS DE LA BANCA :
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JOAO PAULO JAVIDI DA COSTA
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JOSE ALFREDO RUIZ VARGAS
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RICARDO ZELENOVSKY
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WALTER DA CRUZ FREITAS JUNIOR
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TARCISIO FERREIRA MACIEL
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Data: 27-jun-2023
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Resumen Espectáculo
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In recent years, massive Multiple-Input-Multiple-Output (MIMO) systems have been the subject of intense research due to their great potential to provide energy efficiency, data rate gains and diversity through the transmission and reception of multiple versions of the same signal for multiusers. However, its performance benefits depend heavily on the channel estimate at the base station and the way the symbol arrays are transmitted. For modeling and estimating received signals, channel modeling and information transmission (symbol matrices) are very important. In estimating the MIMO channel, it is important to accurately estimate all the parameters that model the channel, such as azimuth and elevation angles, path directions, polarization and amplitude parameters on both sides of the link. For the transmitted symbols it is important to estimate the information received as accurately as possible, for this, in the transmission of the symbols in most cases we use spatial, temporal or frequency coding to increase the diversity of the systems. These codings generally improve the performance, the reliability of the systems and a better estimate of the received signals. In this context, in recent years, semi-blind receivers based on tensor decompositions for MIMO massive systems have been extensively studied. These receivers allow us a better estimate of the channel and symbols without any information about the channel. In some cases, in addition to estimating the channel, it is possible to estimate the channel parameters. This thesis presents received signal model based on tensor decompositions that combine a extension of the MKronST coding and 5th-order channel tensor to transmit the symbols. The coding extension is based on the combination of the tensor space time (TST) coding and the multiple Kronecker product of symbol matrices, called TST-MSMKron coding. The channel assumes a uniform rectangular array (URA) at both, transmitter and receiver which allows us to model the channel as a tensor. More specifically, the theoretical contributions of this thesis are around the proposal of new semi-blind receivers to jointly estimate the symbol matrices, channel and channel parameters without prior knowledge of the channel and channel parameters. What makes this semi-blind estimation possible is the use of the TST-MSMKron coding to transmit the signal. In the first part of this thesis, a multidimensional CX decomposition for tensors is proposed. CX Decomposition is applied to data reconstruction. Based on CX model, one algorithm is proposed to estimate and reconstruct the data tensor. In the second part of this thesis, the TST- MSMKron coding is presented for massive MIMO systems, where a model of the received signal is proposed that combines a 5th-order channel with the TST-MSMKron coding. This system allows us to model the received signal as a coupled-nested-TuckerPARAFAC. In addition, semi-blind receivers in two steps are proposed to jointly estimate the symbols, the channel and the channel parameters. Conditions related to the identifiability and the computational complexity of the proposed algorithms are also discussed in both parts of the thesis. In each part of the thesis, results from Monte Carlo simulations are provided to evaluate the performance of the proposed algorithms. Results show the efficiency of the algorithms in the reconstruction of the datas and joint estimation of the symbols, channel and channel parameters of the system, respectively: In recent years, massive Multiple-Input-Multiple-Output (MIMO) systems have been the subject of intense research due to their great potential to provide energy efficiency, data rate gains and diversity through the transmission and reception of multiple versions of the same signal for multiusers. However, its performance benefits depend heavily on the channel estimate at the base station and the way the symbol arrays are transmitted. For modeling and estimating received signals, channel modeling and information transmission (symbol matrices) are very important. In estimating the MIMO channel, it is important to accurately estimate all the parameters that model the channel, such as azimuth and elevation angles, path directions, polarization and amplitude parameters on both sides of the link. For the transmitted symbols it is important to estimate the information received as accurately as possible, for this, in the transmission of the symbols in most cases we use spatial, temporal or frequency coding to increase the diversity of the systems. These codings generally improve the performance, the reliability of the systems and a better estimate of the received signals. In this context, in recent years, semi-blind receivers based on tensor decompositions for MIMO massive systems have been extensively studied. These receivers allow us a better estimate of the channel and symbols without any information about the channel. In some cases, in addition to estimating the channel, it is possible to estimate the channel parameters. This thesis presents received signal model based on tensor decompositions that combine a extension of the MKronST coding and 5th-order channel tensor to transmit the symbols. The coding extension is based on the combination of the tensor space time (TST) coding and the multiple Kronecker product of symbol matrices, called TST-MSMKron coding. The channel assumes a uniform rectangular array (URA) at both, transmitter and receiver which allows us to model the channel as a tensor. More specifically, the theoretical contributions of this thesis are around the proposal of new semi-blind receivers to jointly estimate the symbol matrices, channel and channel parameters without prior knowledge of the channel and channel parameters. What makes this semi-blind estimation possible is the use of the TST-MSMKron coding to transmit the signal. In the first part of this thesis, a multidimensional CX decomposition for tensors is proposed. CX Decomposition is applied to data reconstruction. Based on CX model, one algorithm is proposed to estimate and reconstruct the data tensor. In the second part of this thesis, the TST- MSMKron coding is presented for massive MIMO systems, where a model of the received signal is proposed that combines a 5th-order channel with the TST-MSMKron coding. This system allows us to model the received signal as a coupled-nested-TuckerPARAFAC. In addition, semi-blind receivers in two steps are proposed to jointly estimate the symbols, the channel and the channel parameters. Conditions related to the identifiability and the computational complexity of the proposed algorithms are also discussed in both parts of the thesis. In each part of the thesis, results from Monte Carlo simulations are provided to evaluate the performance of the proposed algorithms. Results show the efficiency of the algorithms in the reconstruction of the datas and joint estimation of the symbols, channel and channel parameters of the system, respectively
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Marlon Marques Soudré
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GPU-Based Embedded Monitoring for Fault Detection and Diagnosis in Time-Varying Nonlinear Systems -A Wind Turbine Case Study
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Líder : CARLOS HUMBERTO LLANOS QUINTERO
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MIEMBROS DE LA BANCA :
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ALVARO BERNAL NOROÑA
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CARLOS HUMBERTO LLANOS QUINTERO
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EDWARD DAVID MORENO ORDONEZ
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JONES YUDI MORI ALVES DA SILVA
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LEANDRO DOS SANTOS COELHO
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Data: 06-dic-2023
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Resumen Espectáculo
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Monitoring non-linear and time-varying systems to detect and diagnose failures is not a trivial task, especially when applied to embedded systems and their restrictions. Despite the challenges, the development and popularization of technologies such as the Internet of Things (IoT), machine learning tools and the Edge Computing paradigm has increased interest in the topic. However, there are still few works included in this scenario, with a space to be filled in terms of solutions that are viable to be implemented. In this sense, the present work proposes contributions based on GPUs in order to contribute to filling this gap in the literature. Firstly, a strategy applied to embedded systems based on GPUs is proposed to identify non-linear and black-box systems. More precisely, a parallelization strategy for the Forward Regression Orthogonal Least Squares (FROLS) algorithm was developed to select parsimonious, linear and non-linear autoregressive models. Then, solutions for fault detection and classification are presented, both mapped onto GPUs and based on the analysis of the parameters of the identified model, implemented with control-chart tools and Support Vector Machines (SVM), respectively. . Finally, the aforementioned solutions were brought together, together with the recursive estimation strategy of the model parameters within a moving window (SWRLS), in order to establish a monitoring algorithm for fault detection and diagnosis (SWRLS\SVM\FROLS ). The solutions proved to be viable when validated with real data from a wind turbine blade subjected to temperature variation and failures resulting from ice accumulation and crack formation at different scales. It is worth highlighting that this case study is current and relevant, combining the characteristics of a time-varying non-linear system, due to failures and environmental factors, and acting in the edge computing paradigm, essential especially for offshore installations. In this sense, the chosen case study explores the proposed solution in its entirety, showing the feasibility of GPU-based embedded monitoring for detecting and diagnosing faults in time-varying non-linear systems.
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