Controle por horizonte retrocedente de sistemas lineares com saltos markovianos e ruido aditivo

Orientadores: João Bosco Ribeiro do Val, Eduardo Fontoura CostaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e de ComputaçãoResumo: A principal contribuição deste trabalho _e propor e resolver um problema de controle de Sistemas Lineares com Saltos Markovianos (SLSM) na presença de ruído que possa existir atuando ininterruptamente sobre estes sistemas. Adotamos o método de controle por horizonte retrocedeste sob a suposição de que os estados da Cadeia de Markov não são conhecidos pelo controlador, com exceção de uma distribuição inicial, e impomos ganhos de realimentacão linear em um problema com complexidade restrita. Incorporamos ao modelo com ruído alvos dinâmicos e entradas exógenas que podem sofrer saltos, com especial interesse em aplicações em modelos macroeconômicos, sistemas robóticos, entre outros. Desenvolvemos uma formulação determinista equivalente ao problema escolástico estudado, em que condições necessárias de otimalidade são propostas e um método iterativo baseado em um procedimento variacional soluciona o problema. Como passo intermediário para a obtenção da solução do problema de rastreamento, desenvolvemos primeiramente a solução do problema de regulação, por este se tratar de um caso particular do primeiro. Algumas aplicações são apresentadas, de forma a ilustrar numericamente a teoria desenvolvidaAbstract: The main contribution of this work is to propose and solve a control problem of Markov Jump Linear Systems (MJLS) driven by noise. We adopted the receding horizon control method assuming that the Markov state chain is not known by the controller, with the exception of an initial distribution. We impose linear feedback gain structure in a problem with restricted complexity. We add to the noisy model switching targets and exogenous inputs variables, which are interesting for applications such as macroeconomic models, robotic systems and others. We develop an equivalent deterministic formulation to the stochastic problem studied where necessary conditions of optimality are proposed and an iterative method based on a variational procedure solves the problem. As an intermediate step to attain the solution to the tracking problem, we develop first the solution to the regulation problem, since this is an particular case of the former. To illustrate numerically the theory developed, some applications are presented.MestradoAutomaçãoMestre em Engenharia Elétric

Sistema de Energy Harvesting empregado a estruturas bioinspiradas usando dispositivo Piezoelétrico PVDF

Recently a growing trend in the technology industry towards the development of autonomous and low-power electronic devices led to the emergence of a relatively new research concept called Energy Harvesting. It is in the interest of such a segment of study to look for new alternatives to derive sources of ambient energy, preferably unconventional, such as vibration, mechanical, solar, thermal, wind, hydraulic, among others unusual, as it were, in small amounts of electrical energy useful for powering low-power electronic devices and circuits. Thus, the present study presents an alternative approach to microscale renewable energy production by exploiting wind potential through wind-induced and mechanical vibrations imposed on small artificial real tree-shaped structures using the piezoelectric polymer Vinylidene Polyfluoride (PVDF) as vertical and horizontal stem. Thus, three models of artificial leaves were developed and investigated in the conversion of mechanoelectric energy, which were called Triangular Leaf I (FTI) and Artificial Leaf I (FAI), both with vertically oriented piezoelectric material (I); and Triangular L-shaped Sheet (FTL), with the horizontally oriented piezoelectric element (L). The results obtained in the study demonstrated a reasonably good performance in converting mechanical oscillations into electricity, especially in the FAI and FTI models. While for the FTL model, it was observed that the use of the PVDF transducer is not the most appropriate in the proposed horizontal configuration, thus requiring future experiments with slightly more rigid materials, such as piezoelectric ceramics. In addition, the maximum output power recorded in the experiments was 3.96 µW for the FAI model and 2.22 µW for the FTI model with wind speeds of 5.66 m / s, surpassing some results found in the literatureRecentemente uma crescente tendência no ramo tecnológico voltado ao desenvolvimento de dispositivos eletrônicos autônomos e de baixo consumo de energia levou ao surgimento de um conceito relativamente novo de pesquisa, chamando Energy Harvesting. É do interesse de tal segmento de estudo buscar novas alternativas de se derivar fontes de energia ambiente, preferencialmente não convencionais, tais como vibrações, cargas mecânicas, solar, térmica, eólica, hidráulica, entre outras pouco usuais, por assim dizer, em pequenas quantidades de energia elétrica útil para alimentar dispositivos e circuitos eletrônicos de baixo consumo de energia elétrica. Dessa forma, o presente estudo apresenta uma abordagem alternativa de produção de energia renovável em microescala explorando o potencial eólico por meio de vibrações mecânicas induzidas e impostas pelo fluxo de vento, sobre pequenas estruturas arquitetônicas artificiais com formato de folha árvore real, empregando o polímero piezoelétrico Polifluoreto de Vinilideno (PVDF) como caule vertical e horizontal. Assim, três modelos de folhas artificiais foram desenvolvidos e investigados na conversão de energia mecanoelétrica, os quais foram denominados Folha Triangular em I (FTI) e Folha Artificial em I (FAI), ambos com o material piezoelétrico orientado verticalmente (I); e Folha Triangular em L (FTL), com o elemento piezoelétrico orientado horizontalmente (L). Os resultados obtidos no estudo demonstraram um desempenho razoavelmente bom na conversão de oscilações mecânicas em eletricidade, especialmente nos modelos FAI e FTI. Enquanto para o modelo FTL, observou-se que o emprego do transdutor PVDF não é o mais adequado na configuração horizontal proposta, havendo assim a necessidade de experimentos futuros com materiais um pouco mais rígidos, como é o caso das cerâmicas piezoelétricas. Ademais, as máximas potências de saída registradas nos experimentos foram de 3,96 µW para o modelo FAI e 2,22 µW para o modelo FTI com velocidades do vento em 5,66 m/s, superando alguns resultados encontrados na literatura

Gradient-based optimization techniques for the design of static controllers for Markov jump linear systems with unobservable modes

The paper formulates the static control problem of Markov jump linear systems, assuming that the controller does not have access to the jump variable. We derive the expression of the gradient for the cost motivated by the evaluation of 10 gradient-based optimization techniques. The numerical efficiency of these techniques is verified by using the data obtained from practical experiments. The corresponding solution is used to design a scheme to control the velocity of a real-time DC motor device subject to abrupt power failuresFAPESP (03 / 06736-7, 04 / 06947-0)CNPq (471557 / 2009-9, 304.856 / 2007-0, 304.429 / 2007-4, 306.466 / 2010-4)Fundación Carolina (Fundación Carolina - Programa "Movilidad de Professores e Investigadores Brasil-España. C.2010 "

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030

Stability and control of linear stochastic systems with long-run average cost criterion

Orientadores: João Bosco Ribeiro do Val, Eduardo Fontoura CostaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenahria Eletrica e de ComputaçãoResumo: Esta monografia apresenta resultados de estabilidade e controle de sistemas estocásticos representados por operadores lineares com respeito ao estado e não-lineares em relação ao controle, quando avaliados no critério de custo médio a longo prazo (CMLP). A estrutura de controle n¿ao depende da historia do processo e pode ser usada, como caso particular, para representar diversos problemas de controle existentes na literatura. Em relação a estabilidade, mostra-se que o sistema estocástico e assintoticamente estável na media se o custo CMLP 'e finito e se as hipóteses de controlabilidade e observabilidade são validas. Para garantir a estabilidade uniforme do segundo momento do sistema, algumas condições adicionais são verificadas. Em relação ao controle, apresentam-se condições que asseguram a existência de política ótima estacionaria no problema CMLP para a classe de sistemas estudados. Uma aproximação é desenvolvida para se obter o mínimo CMLP, e esta aproximação é ilustrada numericamente no problema de regulação de sistemas lineares sujeitos a saltos markovianos, supondo que o controlador não possui acesso ao estado de Markov. Exemplos numéricos são empregados para ilustrar a teoria desenvolvida.Abstract: This monograph presents results on stability and control of stochastic systems represented by linear operators with respect to the state which are non-linear with respect to the control. The control seeks to optimize a long run average cost (LRAC). The control structure does not depend on the past history of the process and it can be used, in particular, to represent a broad range of control problems that appears in the literature. Regarding the stability, it is shown that the stochastic system is asymptotically stable in the mean if the LRAC is finite and if controllability and observability assumptions are satisfied. To guarantee the uniform second moment stability, some additional conditions must be verified. With respect to the control, the main goal is to assure the existence of an optimal stationary policy for the LRAC problem within the class of systems considered, and some independent conditions are derived. An approximation for the minimum LRAC is obtained, and it is illustrated numerically for the regulator problem of Markov jump linear systems, under the assumption that the controller does not have access to the Markov state. Numerical examples illustrate the derived theory.DoutoradoAutomaçãoDoutor em Engenharia Elétric

Toxicological, clinic-pathological and ultrastructural aspects of iatrogenic and experimental poisoning by vitamin D in rabbits

Toxicological, clinic-pathological and ultrastructural aspects of iatrogenic and experimental subcutaneous poisoning in rabbits by vitamin D are described. Clinically the animals showed signs of cardiovascular insufficiency, as ascite and lung edema, hyporexia, anorexia, mucous diarrhoea, loss of weight and apathy. The classical alterations of minera-lization and, occasionally, ossification of the cardiovascular system, as well the lesions of kidneys, lungs, stomach, among other organs, were reproduced by the subcutaneous administration of an oily solution of cholecalciferol (non-activated vitamin D3).São descritos aspectos toxicológicos, clínico-patológicos e ultraestruturais de coelhos intoxicados iatrogênica e experimentalmente por vitamina D por via subcutânea. Clinicamente, os animais evidenciaram sinais de insuficiência cardiovascular como ascite e edema pulmonar, hiporexia, anorexia, diarréia mucosa, emagrecimento e apatia. As clássicas alterações de mineralização e, por vezes, osseificação, do sistema cardiovascular, bem como as alterações de rins, pulmões, estômago, entre outros órgãos, foram reproduzidas com administrações subcutâneas de solução oleosa de colecalciferol (vitamina D3 não-ativada)