A contribution to the use of Hopfield neural networks for paramater estimation

This paper presents a contribution to the use of Hopfield neural networks (HNNs) for parameter estimation. Our focus is on time-invariant systems that are linear in the parameters. We introduce a suitable HNN and present a weaker condition than the currently existing ones that guarantees the convergence of the parameterization estimated by the network to the actual parameterization. The application of our results is illustrated in a parameter estimation problem for a two carts system

Study of Voltage Fluctuations Caused in a Distribution Grid by the Connection of a Wave Energy Converter and Corrective Actions Based on Reactive Power Compensation

AbstractRenewable energies, in general, have considerably increased their penetration in electrical power systems. However, they are intermittent energy sources, and large amounts of this power could create problems for the proper operation of the electrical network. In this sense, this paper studies the effects of wave energy generation on the voltages in a distribution network, using the IEEE 34-bus test feeder. In addition, corrective actions based on reactive power compensation, such as reactive compensation from the grid-side converter of the wave energy converter and the use of a STATCOM, are presented. The results show that the use of the grid-side converter as a reactive power compensator improves the voltage quality in the network, although its capability to mitigate voltage fluctuations is limited. The use of a complementary external STATCOM can provide for extra compensation if needed

Sistema Inteligente de Deteção de Pessoas para Robôs Móveis Autónomos de Desinfeção

A pandemia de COVID-19, provocada pela propagação descontrolada do vírus SARS-CoV-2, levou à necessidade de desenvolver sistemas de desinfeção inteligentes, não só para proteger as pessoas que frequentam espaços públicos, mas também para proteger aqueles que estejam sujeitos a situações de risco em zonas contaminadas. Nesta dissertação, é desenvolvido um sistema de deteção de pessoas inteligente para robôs autónomos de desinfeção que utilizam radiação Ultravioleta do tipo C para esse propósito. A desinfeção é interrompida pelo sistema quando uma pessoa é detetada à volta do robô, em qualquer direção. A radiação UVC é perigosa para humanos e, como tal, o sistema de deteção proposto tem como objetivo proteger as pessoas, desativando o processo de desinfeção assim que uma pessoa seja detetada. O sistema utiliza três tipos de sensores para a deteção, uma câmera RGB Raspberry Pi, uma câmera térmica FLIR Lepton 3.5 e quatro sensores PIR, fundindo posteriormente os dados por eles recolhidos. As imagens RGB e térmicas são processadas com recurso uma rede neuronal Single Shot Detector Mobilenet, para identifcar e detetar pessoas com recurso a métodos de inteligência artificial. A câmera térmica é ainda utilizada para gerar um histograma de temperaturas para cada imagem processada, que contribui para o algoritmo de deteção desenvolvido. Os resultados mostram que a fusão sensorial dos diferentes sensores melhora o desempenho do sistema, quando comparado a situações em que os sensores são utilizados individualmente. Um dos testes realizados mostra a capacidade do sistema em distinguir pessoas em fotografias de pessoas reais, através da fusão dos dados da câmera térmica com os dados da câmera RGB. Os resultados da deteção validam o sistema proposto. O sistema tem ainda dois sensores extra que comunicam diretamente com o robô de desinfeção que são um LiDAR para cálculo de área na direção da deteção e um sonar para medir a distância do robô ao teto.The COVID-19 virus outbreak led to the need of developing smart disinfection systems, not only to protect the people that usually frequent public spaces but also to protect those who have to subject themselves to the contaminated areas. In this dissertation it is developed a human detector smart sensor for autonomous disinfection mobile robots that uses Ultraviolet C type light for the disinfection task. The disinfection is interrupted by the system when a human is detected around the robot in any direction. UVC light is dangerous for humans and thus the need for a human detection system that will protect them by disabling the disinfection process, as soon as a person is detected. This system uses different sensors, a RGB Raspberry Pi Camera as well as a FLIR Lepton 3.5 Thermal Camera and also four PIR sensors and combines the data gathered by them. The RGB and Thermal images are processed with a Single Shot Detector Mobilenet neural network to identify and detect persons. The thermal camera also generates a temperature histogram for each processed image. Results show that the sensorial fusion of the diffentent sensors data improves the system performance compared to when the sensors are used individually. One of the tests performed proves that the system is able to distinguish a person in a picture from a real person by fusing the thermal camera and the visible light camera data. The detection results validate the proposed system. The system also possesses two extra sensors that communicate directly with the desinfection robot, a LiDAR to measure the area in the detection direction and a sonar to measure the distance from the robot to the ceiling

Efeitos de fungicidas no tratamento de sementes de soja sobre Colletotrichum Truncatum, Cercospora Kikuchii e Fusarium Semitectum.

It is known that soybean seeds are a vehicle of pathogens, causing a proliferation of undesirable diseases, often already known by the local producer, or introducing a new pathogen in the location, and for better control of this situation, it is recommended the seed treatment, and thus performing a better control of diseases that may manifest themselves in the culture to be established. Given this scenario, the present work aimed to evaluate pathogens present in lots of field seeds, through the filter paper method (Blotter test), as well as to evaluate the effect of 16 chemical products in the management of these pathogens. Therefore, the objective of this work was to evaluate the incidence of Cercospora kikuchii, Colletotrichum truncatum and Fusarium semitectum in seeds treated with fungicides. Other diseases, such as Cladosporium sp., Phomopsis sojae, Penicillium spp., Aspergillus flavus, were analyzed, where the treatments used effectively controlled these pathogens, thus not requiring statistical analysis of these pathogens. The fungicides used were from the chemical groups strobilurins, triazoles, isophthalonitriles, organostannins, morpholine, bezimidazoles, carboxamides, pyrazoles, alkylenebis, and fermented fungicides, seeking the performance of different classes of fungicides, to better distinguish the effectiveness of fungicides. After the application of treatments, the seeds were incubated for 7 days, at 20° C with a variation of 2°C more or less, with the aid of photoperiod lights and a controlled environment. In each treatment 300 seeds were evaluated. The experiment was conducted in the laboratory of the Federal University of Uberlândia - MG, in a randomized block design, with 17 treatments and three repetitions. The evaluations are done using a microscope, for better identification and quantification of the fungus present, and thus, counted per gerbox, to obtain the exact amount of each fungus in each treatment, and observe the efficiency of each treatment. For control of Fusarium semitectum, the treatments T5 (Tebuconazole + Chlorothalonil), T13 (Bixafem + Prothioconazole + Trifloxystrobin) and T14 (Benzovindiflupir + Prothioconazole), whose commercial names are, respectively, Fezan gold, Fox Xpro and Mitrion, stood out. For control of Fusarium semitectum, the one that showed the worst results was the control control. Treatments that were intermediate according to the statistics were T3 (Trifloxystrobin + Cyproconazole), T7 (Metiram + Pyraclostrobin), and T12 (fermented fungus). For control of Cercospora kikuchii, treatment T6 (Fentin hydroxide) stood out. For control of Cercospora kikuchii, the worst treatments were the witness, followed by T3 (Trifloxystrobin + Cyproconazole), and T13 (Bixafem + Protioconazole + Trifloxystrobin). For control of Colletotrichum truncatum, all treatments stood out, except the witness and T4 (Chlorothalonil).Trabalho de Conclusão de Curso (Graduação)Sabe-se que, as sementes de soja são um veículos de agentes patogênicos, fazendo com que ocorra uma proliferação de doenças indesejáveis, muitas das vezes já conhecidas pelo produtor local, ou introduzindo um novo patógeno no local, e para um melhor controle desta situação, recomenda-se o tratamento de sementes, e assim realizando um melhor controle das doenças que possam se manifestarem na cultura a ser estabelecida. Diante deste cenário, o presente trabalho teve como objetivo avaliar patógenos presentes em lotes de sementes de campo, através do método de papel de filtro (Blotter test), além de avaliar o efeito de 16 produtos químicos no manejo destes patógenos. Portanto, o objetivo do trabalho foi avaliar a incidência de Cercospora kikuchii, Colletotrichum truncatum e Fusarium semitectum em sementes tratadas com fungicidas. Foram analisadas outras demais doenças, como Cladosporium sp., Phomopsis sojae, Penicillium spp., Aspergillus flavus, onde os tratamentos utilizados controlaram de forma efetiva estes patógenos, assim não sendo necessário a análise estatística destes patógenos. Os fungicidas utilizados foram dos grupos químicos estrobilurinas, triazois, isoftalonitrilas, organoestanicos, morfolina, bezimidazois, carboxamidas, pirazois, alquilenobis, e fermentado de fungos, buscando a atuação de diferentes classes de fungicidas, para melhor distinção de efetividade dos fungicidas. Após a aplicação dos tratamentos, as sementes foram incubadas por 7 dias, a 20° C com variação de 2°C a mais ou a menos, com o auxílio de luzes de fotoperíodo e ambiente controlado. Em cada tratamento foram avaliadas 300 sementes. O experimento foi conduzido no laboratório da Universidade Federal de Uberlândia – MG, em delineamento de blocos casualizado, sendo 17 tratamentos com três repetições. As avaliações são feitas através do uso de microscópio, para melhor identificação e quantificação dos fungos presentes, e assim, contabilizados por caixa gerbox, para assim, obter a quantidade exata de cada fungo em cada tratamento, e observar a eficiência de cada tratamento. Para controle de Fusarium semitectum, destacaram-se os tratamentos T5 (Tebuconazol + Clorotalonil), T13 (Bixafem + Protioconazol + Trifloxistrobina) e T14 (Benzovindiflupir + Protioconazol), cujo nome comercial são, respectivamente, Fezan gold, Fox Xpro e Mitrion. Para controle de Fusarium semitectum, o que apresentou pior resultado foi a testemunha. Tratamentos que foram intermediários de acordo com a estatística foram T3 (Trifloxistrobina + Ciproconazol), T7 (Metiram + Piraclostrobina), e T12 (fermentado fúngico). Para controle de Cercospora kikuchii, destacou o tratamento T6 (Hidróxido de fentina). Para controle de Cercospora kikuchii, os piores tratamentos foram a testemunha, seguida por T3 (Trifloxistrobina + Ciproconazol), e T13 (Bixafem + Protioconazol + Trifloxistrobina). Para controle de Colletotrichum truncatum, destacaram-se todos os tratamentos, exceto a testemunha e o T4 (Clorotalonil)

Multiple model adaptive control of neuromuscular blockade: Design guidelines and clinical cases

The high level of uncertainty of the dynamic response of patients subject to anaesthesia motivates the use of adaptive control methods. This paper proposes an approach based on Switched Multiple Model Adaptive Control (SMMAC) to tackle this problem in what concerns the control of the neuromuscular blockade level. It is shown how to design the different elements of the SMMAC controller, enhancing the importance of the observer polynomial, that is shown to be instrumental to stabilize the loop. Clinical results using atracurium as blocking agent are reported, thereby illustrating the application of the proposed approach in actual clinical practice

A aprendizagem da matemática com recurso à história : uma proposta pedagógica para o 5.º ano

Relatório de estágio de mestrado, Educação (Didática da Matemática), Universidade de Lisboa, Instituto de Educação, 2013Este estudo procura compreender em que medida o desenvolvimento e a implementação de uma proposta pedagógica suportada por tarefas baseadas na História da Matemática conduzem a uma aprendizagem significativa dos racionais não negativos (frações), do perímetro do círculo (e respetiva compreensão do significado do π) e da área do círculo em alunos do 5.º ano. Especificamente, o estudo visa analisar as estratégias utilizadas pelos alunos, as dificuldades que evidenciam e os conhecimentos anteriores que mobilizam na resolução dessas tarefas, bem como as aprendizagens por eles realizadas. Além disso, pretende promover uma reflexão sobre a própria prática, uma vez que a proposta pedagógica se desenvolve no quadro da prática letiva do investigador, numa escola pública pertencente ao concelho de Odivelas, zona que se situa na periferia norte de Lisboa. O estudo é fundamentado nas orientações curriculares e por uma revisão de literatura sobre História da Matemática e o seu papel no ensino e aprendizagem desta disciplina. Na recolha de dados utilizei a observação participante, com registo de notas de campo, a gravação áudio e vídeo das aulas onde se aplicaram as tarefas e a recolha documental dos trabalhos elaborados pelos alunos. Os resultados do estudo evidenciam que os alunos utilizam estratégias diversificadas na exploração das tarefas, estabelecendo conexões com vários tópicos matemáticos. Identificam-se, porém, algumas dificuldades matemáticas que se salientaram, como é o caso da conceção da unidade relativa às frações, e outras que se vão dissipando com o decorrer da proposta pedagógica, nomeadamente a compreensão da natureza de pi que vai sendo enriquecida pela contextualização histórica. Os conhecimentos mobilizados são relativos a vários tópicos matemáticos estudados anteriormente à implementação desta proposta pedagógica e aos tópicos que foram sendo construídos ao longo da mesma, destacando-se a contribuição da construção do conceito de fração para o estudo do número pi e a utilização de alguns conhecimentos históricos que permitem aos alunos justificar as suas ideias e conjeturas sobre a irracionalidade deste número. Os resultados parecem evidenciar que a História da Matemática propicia aprendizagens significativas para os alunos.This study aims to understand how the development and the implementation of a pedagogical proposal, supported by tasks based on the History of Mathematics, contributes to 5th grade students’ significant learning of non-negative rational numbers (fractions), circus perimeter (and the associated understanding of the π value) and its area. Specifically, this study seeks to analyze the strategies used by students, the difficulties they faced and the previous knowledge they mobilized when solving the proposed tasks, as well as their learning. Moreover, it intends to promote a reflection about my own practice as this pedagogical proposal develops itself in a class of a public school at Odivelas, surroundings of Lisbon, where I am also a teacher. The study stands on the curricular orientations and a literature review on History of Mathematics and its role in the teaching and learning process. Data collection methods include participant observation and the respective field notes, audio and video recordings of the classes where the tasks were applied as well as the students’ written reports. The results show that the students use diverse strategies in the exploration of the tasks, establishing connections with several mathematical topics. Some mathematical difficulties were identified as, for instance, the connection between fractions and their unities, while others were decreasing with the continuous work on this pedagogical proposal, namely the comprehension of pi which was enhanced by its historical meaning. The knowledge mobilized was both related to several previously studied mathematical topics and to new others built during the implementation of this proposal, with emphasis on the development of fractions for the study of pi and the use of some historical knowledge that allow students to justify their own ideas on the irrationality of this number. The results of this study also seem to confirm that the use of tasks based on the History of Mathematics has several potentialities in students’ learning

Flow-3D Modelling of the Debris Effect on Maximum Scour Hole Depth at Bridge Piers

Bridge foundations are frequently inserted in riverbeds constituted by alluvial material, being, therefore, subjected to scouring processes. Such phenomenon is aggravated during flood events due to the increase of water flow or due to the increase of the debris carried by the flow that can pile up along the bridge structural elements. The debris can partially obstruct bridge spans and accumulate near bridge piers and abutments, which will have consequences in terms of reduction of flow capacity and an increment of the maximum scour depth. The dimensions, shape and its location are characteristics that must be considered when predicting the scour depth. The present study aims at analyzing the effect of the debris on the maximum clear-water scour depth at cylindrical piers inserted in uniform sand, non-ripple forming sand, fully-developed turbulent flows in wide rectangular channel, using computational fluid dynamics software, Flow-3D. For this purpose, debris with a triangular and rectangular shape, floating and on the sand bed, were tested, using the k-ε RNG turbulence model and the numerical results were compared with those obtained experimentally. It was possible to verify that the floating debris gives greater scour hole depth and the debris on sand bed behave as scour countermeasure reducing the scour hole depth. Also, rectangular shaped debris seems to cause more scour near the structures than the triangular shaped ones, which also seemed beneficial to the scour hole, by reducing it. However, the results obtained computationally are significantly lower than those obtained experimentally.info:eu-repo/semantics/publishedVersio

Circulating inflammatory mediators and organ dysfunction after cardiovascular surgery with cardiopulmonary bypass: a prospective observational study

INTRODUCTION: Cardiovascular surgery with cardiopulmonary bypass (CPB) has improved in past decades, but inflammatory activation in this setting is still unpredictable and is associated with several postoperative complications. Perioperative levels of macrophage migration inhibitory factor (MIF) and other inflammatory mediators could be implicated in adverse outcomes in cardiac surgery. METHODS: Serum levels of MIF, monocyte chemoattractant protein (MCP)-1, soluble CD40 ligand, IL-6 and IL-10 from 93 patients subjected to CPB were measured by enzyme-linked immunosorbent assay and compared with specific and global postoperative organ dysfunctions through multiple organ dysfunction score (MODS) and sequential organ failure assessment (SOFA). RESULTS: Most of the cytokines measured had a peak of production between 3 and 6 hours after CPB, but maximum levels of MIF occurred earlier, at the cessation of CPB. Among specific organ dysfunctions, the most frequent was hematological, occurring in 82% of the patients. Circulatory impairment was observed in 73.1% of the patients, and 51% of these needed inotropics or vasopressors within the first 24 hours after surgery. The third most frequent dysfunction was pulmonary, occurring in 48.4% of the patients. Preoperative levels of MIF showed a relevant direct correlation with the intensity of global organ dysfunction measured by SOFA (ρ = 0.46, p < 0.001) and MODS (ρ = 0.50, p < 0.001) on the third day after surgery. MCP-1 production was associated with postoperative thrombocytopenia, and MIF was related to the use of a high dose of vasopressors in patients with cardiovascular impairment and also to lower values of the ratio of partial arterial oxygen tension (PaO(2)) to fraction of inspired oxygen (FiO(2)) registered in the first 24 hours after CPB. CONCLUSION: Despite the multifactorial nature of specific or multiple organ dysfunctions, MIF should be explored as a predicting factor of organ dysfunction, or even as a potential therapeutic target in decreasing postoperative complications