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A comparative analysis of the relative efficacy of vector-control strategies against dengue fever

Amaku, Marcos; Coutinho, Francisco Antonio Bezerra; Raimundo, Silvia Martorano; Lopez, Luis Fernandez; Burattini, Marcelo Nascimento; Massad, Eduardo
Fonte: Springer; Nova York Publicador: Springer; Nova York
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
55.9%
Dengue is considered one of the most important vector-borne infection, affecting almost half of the world population with 50 to 100 million cases every year. In this paper, we present one of the simplest models that can encapsulate all the important variables related to vector control of dengue fever. The model considers the human population, the adult mosquito population and the population of immature stages, which includes eggs, larvae and pupae. The model also considers the vertical transmission of dengue in the mosquitoes and the seasonal variation in the mosquito population. From this basic model describing the dynamics of dengue infection, we deduce thresholds for avoiding the introduction of the disease and for the elimination of the disease. In particular, we deduce a Basic Reproduction Number for dengue that includes parameters related to the immature stages of the mosquito. By neglecting seasonal variation, we calculate the equilibrium values of the model’s variables. We also present a sensitivity analysis of the impact of four vector-control strategies on the Basic Reproduction Number, on the Force of Infection and on the human prevalence of dengue. Each of the strategies was studied separately from the others. The analysis presented allows us to conclude that of the available vector control strategies...

Análise de propostas de estratégias de controle para algumas topologias de multiconversores monofásicos.; Analysis of control strategies for some single-phase multiconverter topologies.

Giaretta, Antonio Ricardo
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/01/2009 PT
Relevância na Pesquisa
55.83%
Este trabalho apresenta as principais topologias de conversores multinível descritos na literatura. É feita uma revisão bibliográfica, apresentando as vantagens e as limitações de cada topologia. A seguir são apresentados os métodos mais usuais de modulação para conversores multinível, bem como os campos de aplicação na indústria e em sistemas de potência As associações de conversores baseadas em conversores do tipo ponte completa monofásica foram escolhidas para um estudo mais detalhado. Para estas topologias são apresentados detalhes sobre as respectivas estratégias de controle e modulação. Inicialmente são apresentados os detalhes da ponte completa monofásica com tensão de saída modulada em PWM com dois e três níveis. A seguir são estudadas as associações série e paralela com barramentos CC isolados. O estudo da associação paralela com barramento CC único é a principal contribuição desta dissertação. Para esta topologia são propostas algumas estratégias de controle. Para todos estes casos são apresentados resultados de simulação e experimentais obtidos com inversores operando com potência reduzida, controlados por DSP.; This work presents the main multilevel converter topologies described in the literature. A bibliography revision is presented...

Estratégias de roteamento e de controle de acesso ao meio para redes de sensores sem fio destinadas a redes urbanas; Routing and medium access control strategies for wireless sensor networks in urban networks

Pantoni, Rodrigo Palucci
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 31/01/2012 PT
Relevância na Pesquisa
55.9%
Este trabalho propõe estratégias de roteamento e de controle de acesso ao meio destinadas as redes urbanas, motivadas pelo monitoramento e controle de variáveis elétricas relacionadas à iluminação pública. Tais estratégias foram desenvolvidas segundo requisitos da aplicação, trabalhos encontrados na literatura, limitações do protocolo IEEE 802.15.4 e as especificações RFC 5548 e IEEE 802.15.4e (draft). As estratégias desenvolvidas foram incorporadas a protocolos encontrados na literatura, as quais geraram protocolos aperfeiçoados para redes urbanas, dentre eles GGPSR e gradiente em função da maior distância, utilizados para o tráfego divergente e convergente, respectivamente. O protocolo GGPSR é composto pelo algoritmo geográfico GPSR, geocast e retransmissões para os vizinhos seguindo o critério do GGPSR em caso de falha. O protocolo baseado na maior distância é composto pelo algoritmo do gradiente, o qual utiliza a maior distância no caso de receptores com pesos de gradiente iguais e retransmissões seguindo o mesmo critério. Foi utilizado um modelo de propagação realista, no qual foi aplicada a estratégia de mapeamento de vizinhos dos nós de acordo com a distância aproximada fornecida pelo atributo do pacote RSSI. Além disso...

Estratégias de controle para isolação ativa de vibrações em barras de pulverizadores agrícolas; Control strategies for active vibration isolation for booms of agricultural sprayers

Pontelli, Cristiano Okada
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 14/12/2012 PT
Relevância na Pesquisa
55.83%
A utilização de sistemas de controle para estabilidade de conjuntos de barras para pulverizadores agrícolas é uma tendência devida principalmente aos problemas ambientais e de custo. Neste trabalho, o comportamento dinâmico de um pulverizador de arrasto é analisado através de um modelo não linear, obtido através de técnicas de modelagem de sistemas multicorpos utilizando-se o programa ADAMS. Foram utilizadas duas estratégias de controle PID e "fuzzy" a partir de medidas obtidas com fusão de sensores. A estratégia de controle clássica PID foi desenvolvida e implementada no modelo não linear no ADAMS através de ferramentas internas existentes no programa. Já a estratégia "fuzzy" foi desenvolvida e implementada no modelo não linear no ADAMS através da técnica de co-simulação ADAMS/Matlab. O comportamento dos sistemas de controle foi investigado através de simulação computacional. Foram testados alguns tipos de entradas (entrada degrau, entrada harmônica, entrada randômica e entrada randômica com descontinuidades bruscas). Em todas as simulações os resultados obtidos com os sistemas de controles ativos mostraram melhor estabilidade do conjunto de barras. Entre as leis de controle implementadas (PID e "fuzzy") não houve grandes diferenças entre as oscilações da barra exceto na entrada do tipo randômica com descontinuidades bruscas. Neste caso a lei de controle "fuzzy" apresentou uma grande melhoria com boa atenuação das oscilações do conjunto de barras quando comparadas com a aplicação do sistema de controle PID.; The use of active control systems for stability of booms in agricultural sprayers trend is mainly due to the environmental and costs question. In this work...

Desenvolvimento e analise de estrategias de controle colaborativo para cadeiras de rodas; Development analyses of collaborative control strategies for wheelchair

Arley de Barros Lombardi Junior
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 04/11/2005 PT
Relevância na Pesquisa
55.95%
Esta tese consiste no desenvolvimento de estratégias de controle para o sistema de motorização servo assistido para cadeirantes. O sistema combina as vantagens do sistema de propulsão motorizado como aumento da acessibilidade e mobilidade com as vantagens do sistema manual que é o aumento da capacidade muscular e cardiovascular. Este sistema de motorização atua somente quando a força de propulsão exercida pelo usuário é superior à um determinado limite, o que evita o desenvolvimento de lesão por esforço repetitivo. Metodologicamente foi definido um modelo biomecânico para análise dos esforços do ciclo de propulsão aliado a um modelo dinâmico do sistema para análise e simulação das rotinas de controle propostas. Para geração das estratégias de controle utilizou-se a metodologia de projeto axiomático integrado as estruturas de controle de sistemas multi-agentes, sistemas subsumption e lógica nebulosa. As rotinas foram testadas no modelo dinâmico onde foi possível determinar sua eficiência. Finalizando o processo de concepção do sistema de controle foi construído um programa para simulação do mesmo e um protótipo em escala controlado por este programa. Concluindo o trabalho apresenta o primeiro desenvolvimento de controle para motorização servo assistida e também a primeira utilização de metodologia de projeto axiomático para desenvolvimento de estratégias de controle; The aim of this dissertation is to develop control strategies for servo-assisted motorization. The system brings the power wheelchair advantages because it increases the accessibility and mobility...

Estratégias de controle direto de torque para motores de indução trifásicos usando controladores fuzzy tipo Takagi-Sugeno e controladores por modos deslizantes; Direct torque control strategies for three-phase induction motors with Takagi-Sugeno fuzzy controllers and sliding mode controllers

José Luis Azcue Puma
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/05/2013 PT
Relevância na Pesquisa
55.95%
Na presente tese de doutorado propõe estratégias de controle por orientação direta de campo (FOC direto) e de controle direto de torque (CDT) com emprego de controladores fuzzy do tipo Takagi-Sugeno (fuzzy T-S). Propõe-se também, uma estratégia de CDT baseado no controle do ¿angulo de carga com o emprego do controle por modos deslizantes (CDT-CMD). As estratégias de controle vetorial propostas são utilizadas para o controle de alto desempenho do motor de indução trifásico. O controlador fuzzy T-S proposto utiliza uma única base de regras para gerar as componentes de eixo direto e de quadratura do vetor espacial da tensão do estator. Isto simplifica a estrutura do controlador fuzzy T-S e em consequência diminui o custo computacional e seu tempo de processamento. Na estratégia de CDT com o controle por modos deslizantes o esforço de controle é sempre o máximo possível no sentido de reduzir os erros do torque e do fluxo. Assim, é possível obter uma resposta rápida no controle do fluxo e do torque. Os resultados de simulação e experimentais são apresentados para validarem as propostas desta tese de doutorado. Os controladores apresentaram um desempenho dinâmico satisfatório pois as referências de torque e de fluxo foram atendidas. Todos os resultados obtidos mostraram-se compatíveis com os resultados apresentados na literatura...

A review of current and emergent biofilm control strategies

Simões, M.; Simões, Lúcia C.; Vieira, M. J.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
55.84%
Microbial adhesion to surfaces and the consequent biofilm formation has been documented in many different environments. Biofilms constitute a protected mode of growth that allows microorganisms to survival in hostile environments, being their physiology and behavior significantly different from their planktonic counterparts. In dairy industry, biofilms may be a source of recalcitrant contaminations, causing food spoilage and are possible sources of public health problems such as outbreaks of foodborne pathogens. Biofilms are difficult to eradicate due to their resistant phenotype. However, conventional cleaning and disinfection regimens may also contribute to inefficient biofilm control and to the dissemination of resistance. Consequently, new control strategies are constantly emerging with main incidence in the use of biosolutions (enzymes, phages, interspecies interactions and antimicrobial molecules from microbial origin). The present review will focus on describing the mechanisms involved in biofilm formation and behavior, deleterious effects associated with their presence, and some of the current and emergent control strategies, providing new insight of concern for food industry.; Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/31661/2006

Biogeography of Triatominae (Hemiptera: Reduviidae) in Ecuador: implications for the design of control strategies

Abad-Franch,Fernando; Paucar C,Aura; Carpio C,Carlos; Cuba Cuba,César A; Aguilar V,H Marcelo; Miles,Michael A
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2001 EN
Relevância na Pesquisa
55.84%
Chagas disease control strategies strongly depend on the triatomine vector species involved in Trypanosoma cruzi transmission within each area. Here we report the results of the identification of specimens belonging to various species of Triatominae captured in Ecuador (15 species from 17 provinces) and deposited in the entomological collections of the Catholic University of Ecuador (Quito), Instituto Oswaldo Cruz (Brazil), the Natural History Museum London (UK), the London School of Hygiene and Tropical Medicine (UK), the National Institute of Hygiene (Quito), and the Vozandes Hospital (Quito). A critical review of published information and new field records are presented. We analysed these data in relation to the life zones where triatomines occur (11 life zones, excluding those over 2,200 m altitude), and provide biogeographical maps for each species. These records are discussed in terms of epidemiological significance and design of control strategies. Findings relevant to the control of the main vector species are emphasised. Different lines of evidence suggest that Triatoma dimidiata is not native to Ecuador-Peru, and that synanthropic populations of Rhodnius ecuadoriensis in southern Ecuador-northern Peru might be isolated from their sylvatic conspecifics. Local eradication of T. dimidiata and these R. ecuadoriensis populations might therefore be attainable. However...

Control strategies applied for reducing the vibration and torque ripple of a special Switched Reluctance Motor

Correa,D. A. P.; Silva,W. M. da; Nabeta,S. I.; Chabu,I. E.
Fonte: Sociedade Brasileira de Microondas e Optoeletrônica e Sociedade Brasileira de Eletromagnetismo Publicador: Sociedade Brasileira de Microondas e Optoeletrônica e Sociedade Brasileira de Eletromagnetismo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 EN
Relevância na Pesquisa
55.89%
Despite its robustness the Switched Reluctance Motors (SRMs) present some inconvenient drawbacks as a major torque ripple, vibration and acoustic noise when compared to other types of motors. These characteristics are usually related to factors such as the salient poles in the stator and in the rotor, the switched feeding and the control strategy imposed by the electronic converter. In this paper a Special Switched Reluctance Motor for fractional horsepower and high speed hand tool was studied in order to minimize its vibration and torque ripple characteristics. This task was accomplished by the development of a simple and flexible motor drive and the combination of two different commutations strategies: the Three Level Control and the Single Pulse with Overlapping Phase Current. The SRM prototype and its drive were constructed and submitted to several tests with the proposed commutation strategies. In the frequency domain the strategies results were considered satisfactory.

Lyapunov-based control strategies for the global control of symmetric VTOL UAVs.

Wood, Rohin
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2007
Relevância na Pesquisa
55.9%
The last decade has seen significant advances in the development of Vertical takeoff and landing (VTOL) unmanned aerial vehicles (UAVs). The emergence of enabling technologies, in addition to the practical usefulness of such systems has driven their development to a point where numerous technology demonstrators and commercial products are now in existence. Of particular interest has been the development of small scale, VTOL UAVs commonly referred to as mini and micro-VTOL UAVs. The versatility and agility of such vehicles offers great potential for the use in clustered, urban environments. Despite recent advancements, the autonomous navigation of VTOL UAVs remains a very challenging research area. The dynamics of VTOL UAVs are heavily nonlinear, underactuated and non-minimum phase. This, coupled with the aggressive maneuvers that such vehicles are expected to execute provides a stimulating problem in dynamic control. This is particularly true in the case of micro-VTOL UAVs. The fast, nonlinear nature of these systems render classical, linear control approaches inadequate. The past twenty years has seen great interest in the development of nonlinear control strategies. This has led to the emergence of a number of standard design tools...

Towards a Political Economy of Tobacco Control in Low- and Middle-Income Countries

Bump, J.B.; Reich, M.R.; Adeyi, O.; Khetrapal, S.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
55.94%
This study provides the basis for constructing a political economy of tobacco control in low- and middle-income countries (LMICs). The authors first undertook a literature review of tobacco control in LMICs to explore the forces that oppose the adoption, implementation, and enforcement of tobacco control strategies. The authors then used the sources collected to conduct a stakeholder analysis, as a first step in constructing a political economy of tobacco control in LMICs. The authors focused primarily at the international level because of the dominant role of transnational tobacco companies (TTCs). The author's review of the literature suggests four broad conclusions. First, a political economy approach has been applied only rarely as a formal analytical methodology in the literature on the tobacco control in LMICs. Second, even when the term "political economy" was used in a document, the paper typically did not explicitly conduct this kind of analysis and did not directly consider political strategies for advancing tobacco control. Third...

Control Strategies for Open-End Winding Drives Operating in the Flux-Weakening Region

SANDULESCU, Paul; MEINGUET, Fabien; KESTELYN, Xavier; SEMAIL, Eric; BRUYERE, Antoine
Fonte: IEEE Publicador: IEEE
EN_US
Relevância na Pesquisa
55.91%
This paper presents and compares control strategies for three-phase open-end winding drives operating in the flux-weakening region. A six-leg inverter with a single dc-link is associated with the machine in order to use a single energy source. With this topology, the zero-sequence circuit has to be considered since the zero-sequence current can circulate in the windings. Therefore, conventional over-modulation strategies are not appropriate when the machine enters in the flux-weakening region. A few solutions dealing with the zero-sequence circuit have been proposed in literature. They use a modified space vector modulation or a conventional modulation with additional voltage limitations. The paper describes the aforementioned strategies and then a new strategy is proposed. This new strategy takes into account the magnitudes and phase angles of the voltage harmonic components. This yields better voltage utilization in the dq frame. Furthermore, inverter saturation is avoided in the zero-sequence frame and therefore zero-sequence current control is maintained. Three methods are implemented on a test bed composed of a three-phase permanent-magnet synchronous machine, a six-leg inverter and a hybrid DSP/FPGA controller. Experimental results are presented and compared for all strategies. A performance analysis is conducted as regards the region of operation and the machine parameters.; Projet SOFRACI/FUI

Estudo da adesão às estratégias de prevenção e controle do linfedema em mastectomizadas; Adherence to lymphedema prevention and control strategies in mastectomized women; Estudio de adhesión a las estrategias de prevención y control del linfedema en mastectomizadas

PANOBIANCO, Marislei Sanches; PARRA, Mariana Vendrami; ALMEIDA, Ana Maria de; PRADO, Maria Antonieta Spinoso; MAGALHÃES, Paola Alexandria Pinto de
Fonte: Universidade Federal do Rio de Janeiro Publicador: Universidade Federal do Rio de Janeiro
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
55.94%
Estudo transversal, descritivo e quantitativo, com o objetivo de identificar a adesão às estratégias para prevenção e tratamento de linfedema e relacioná-la à ocorrência do edema do membro superior homolateral à cirurgia, em mulheres mastectomizadas. O estudo foi realizado no Núcleo de Ensino Pesquisa e Assistência na Reabilitação de Mastectomizadas (REMA), da Escola de Enfermagem de Ribeirão Preto/USP, entre 5 de fevereiro e 29 de junho de 2007. Participaram 65 mulheres, que responderam questionário elaborado de acordo com a literatura pertinente à prevenção e controle do linfedema pós-mastectomia. Os resultados mostraram que as mulheres têm conhecimento sobre as estratégias de prevenção e controle do linfedema pós-cirurgia para o câncer de mama, porém, grande parte delas não têm consciência da necessidade e importância da aplicabilidade de tais estratégias. Conclui-se que são necessários esclarecimentos convincentes dessa necessidade de adesão às estratégias de prevenção e controle, diante da gravidade das complicações devidas ao linfedema.; This cross-sectional, descriptive and quantitative study aimed to identify adherence to lymphedema prevention and treatment strategies and relate it with the occurrence of upper limb edema on the same side of the surgery among mastectomized women. The study was carried out in the Teaching...

American visceral leishmaniasis: disease control strategies in dracen microregion in alta paulista, SP, Brazil

D'Andrea,LAZ; Camargo-Neves,VLF; Sampaio,SMP; Kronka,SN; Sartor,IF
Fonte: Centro de Estudos de Venenos e Animais Peçonhentos - CEVAP, Universidade Estadual Paulista - UNESP Publicador: Centro de Estudos de Venenos e Animais Peçonhentos - CEVAP, Universidade Estadual Paulista - UNESP
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2009 EN
Relevância na Pesquisa
55.85%
Despite measures adopted to control American visceral leishmaniasis (AVL), the disease is spreading in a fast and worrying way throughout western São Paulo state. The aim of this work was to study the variables involved in the disease cycle as well as the effectiveness of controlling measures. The study was carried out in the microregion of Dracena, which is composed of twelve cities and belongs to Alta Paulista, a region of western São Paulo. The necessary data were provided by the Superintendence for Endemic Disease Control and Adolfo Lutz Institute, Regional Laboratory of Presidente Prudente. From August 2005 to January 2008, the following factors were observed: detection of phlebotomine sandflies in the cities and periods in which dogs or humans were diagnosed; number of human deaths; prevalence of suspected dogs tested by serology; percentage of euthanasia in suspected dogs; a possible correlation between positive dogs and cases of the disease in humans; and the disease prevalence among municipalities from the studied region. It was verified that, despite the strategies adopted in Dracena microregion to control AVL, the disease continues to rise. Thus, some procedures of the AVL Monitoring and Control Program should be reviewed...

Sufficient statistics for linear control strategies in decentralized systems with partial history sharing

Mahajan, Aditya; Nayyar, Ashutosh
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 11/03/2014
Relevância na Pesquisa
55.93%
In decentralized control systems with linear dynamics, quadratic cost, and Gaussian disturbance (also called decentralized LQG systems) linear control strategies are not always optimal. Nonetheless, linear control strategies are appealing due to analytic and implementation simplicity. In this paper, we investigate decentralized LQG systems with partial history sharing information structure and identify finite dimensional sufficient statistics for such systems. Unlike prior work on decentralized LQG systems, we do not assume partially nestedness or quadratic invariance. Our approach is based on the common information approach of Nayyar \emph{et al}, 2013 and exploits the linearity of the system dynamics and control strategies. To illustrate our methodology, we identify sufficient statistics for linear strategies in decentralized systems where controllers communicate over a strongly connected graph with finite delays, and for decentralized systems consisting of coupled subsystems with control sharing or one-sided one step delay sharing information structures.

How to Evolve Safe Control Strategies

Greenwood, G. W.; Song, X.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 03/08/2002
Relevância na Pesquisa
55.88%
Autonomous space vehicles need adaptive control strategies that can accommodate unanticipated environmental conditions. The evaluation of new strategies can often be done only by actually trying them out in the real physical environment. Consequently, a candidate control strategy must be deemed safe--i.e., it won't damage any systems--prior to being tested online. How to do this efficiently has been a challenging problem. We propose using evolutionary programming in conjunction with a formal verification technique (called model checking) to evolve candidate control strategies that are guaranteed to be safe for implementation and evaluation.; Comment: 3 pages, 1 figure

Application of control strategies in wastewater treatment plants for effluent quality improvement, costs reduction and effluent limits violations removal

Santín López, Ignacio
Fonte: [Barcelona] : Universitat Autònoma de Barcelona, Publicador: [Barcelona] : Universitat Autònoma de Barcelona,
Tipo: Tesis i dissertacions electròniques; info:eu-repo/semantics/doctoralThesis; info:eu-repo/semantics/publishedVersion Formato: application/pdf
Publicado em //2015 ENG
Relevância na Pesquisa
55.91%
En este trabajo se aplican diferentes estrategias de control en las plantas de tratamiento de aguas residuales. El primer objetivo es la mejora del rendimiento de control. Básicamente, esto sirve como una prueba de que la estrategia de control propuesta se ha aplicado correctamente. El objetivo final es el efecto de la estrategia de control aplicada sobre el rendimiento de la planta. En concreto, mejorar la calidad del efluente, reducir costes de operación y evitar violaciones de los límites establecidos en el efluente. La evaluación de las diferentes estrategias de control se lleva a cabo en primer lugar con el Benchmark Simulation Model No. 1 (BSM1), y en segundo lugar con Benchmark Simulation Model No. 2 (BSM2). BSM1 se centra en el tratamiento biológico mediante reactores de lodos activos, y la evaluación se basa en una semana de simulación. BSM2 es una versión extendida del BSM1, agregando el tratamiento de lodos y proporciona un afluente más elaborado y variable, con un año de evaluación. Los enfoques de control se basan en Control Predictivo basado en Modelo, control difuso, funciones que relacionan las variables de entrada y las manipuladas, y Redes Neuronales Artificiales. El Control Predictivo basado en Modelo se propone para una mejora del tracking. El control difuso y las funciones se implementan para mejorar los procesos de desnitrificación o de nitrificación en base a los objetivos propuestos. Sus parámetros de sintonía se seleccionan mediante análisis trade-off. Las Redes Neuronales Artificiales se aplican para detectar riesgo de violaciones y obtener una selección automática de la estrategia de control adecuada. Se muestran los resultados y se comparan con las estrategias de control por defecto y con la literatura. Para el rendimiento de control...

A Pilot Expert Elicitation to Assess the Risks of Malaria Vector Control Strategies in East Africa

Beerbohm, Elissa
Fonte: Universidade Duke Publicador: Universidade Duke
Tipo: Masters' Project Formato: 285420 bytes; application/pdf
Publicado em /05/2007 EN_US
Relevância na Pesquisa
65.84%
Perhaps no other issue has divided the environmental and health communities as much as DDT. The re-introduction of DDT in several East African countries, as well as the demand for evidence-based policy, has led researchers at Duke University to develop the Malaria Decision Analysis Support Tool (MDAST). One facet of the MDAST is to assess the economic, environmental, and human health risks associated with alternative strategies for managing malaria. In this pilot survey and elicitation, risks are assessed for the two most commonly used vector control strategies – indoor residual spraying and insecticide-treated bednets – in Uganda, Tanzania, and Kenya. The elicitation encompasses a broad range of hazard pathways and risks, including harm to nontarget species, agricultural trade restrictions, and vector resistance, some of which are frequently neglected in the policy debate. Preliminary results from the survey indicate that decision-makers are highly concerned with the emergence of vector resistance from ITNs, IRS with DDT, and IRS with ICON. High levels of concern were present for all additional risks associated with DDT, including human health impacts, environmental impacts, and trade restrictions. Results from the elicitation revealed that experts assessing harm to nontarget species and the potential for trade restrictions attributed the highest level of risk to mismanagement of DDT and ICON. Results from the elicitation for vector resistance were even more alarming; the expert assessed high risks of the potential for vector resistance to occur from all pathways associated with permethrin-treated bednets and IRS with DDT. Again...

Robust control strategies for hybrid solid oxide fuel cell systems

Allag, Tahar
Fonte: Rochester Instituto de Tecnologia Publicador: Rochester Instituto de Tecnologia
Tipo: Tese de Doutorado
Relevância na Pesquisa
55.92%
Solid Oxide Fuel Cell (SOFC) systems are electrochemical energy conversion devices characterized by the use of solid oxide as the electrolyte. They operate at high temperatures (between 800± ¡ 1000±C). Mitigating fuel starvation and improving load-following capability of SOFCs are conflicting control objectives. In this thesis, this issue is addressed using a hybrid SOFC ultra-capacitor configuration. The fuel cell is controlled by incorporating a steady-state property of fuel utilization into an input-shaping framework. Two comprehensive control strategies are developed. The first is a Lyapunov-based nonlinear control and the second is a standard H-infinity robust control. Both strategies additionally control the state of charge (SOC) of the ultra-capacitor that provides transient power compensation. A hardware-in-the-loop test-stand is developed where the proposed control strategies are verified. An investigation to improve the hybrid fuel cell system by incorporating a lithium-ion battery as an additional power source is conducted. Combining both battery and ultra-capacitor with a fuel cell is potentially a winning combination especially for high power applications. A novel SOC estimation method for lithium-ion battery is investigated. Based on the combined ultra-capacitor battery hybrid system...

The Interpretation of Discontinuous State Feedback Control Laws as Nonanticipative Control Strategies in Differential Games

Vinter, R; Clark, J M C; James, Matthew
Fonte: Institute of Electrical and Electronics Engineers (IEEE Inc) Publicador: Institute of Electrical and Electronics Engineers (IEEE Inc)
Tipo: Artigo de Revista Científica
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In differential games, one player chooses a feedback strategy to maximize a payoff. The other player counters by applying a minimizing open loop control. Classical notions of feedback strategies, based on state feedback control laws for which the corresponding closed loop dynamics uniquely define a state trajectory, are too restrictive for many problems, owing to the absence of minimizing classical feedback strategies or because consideration of classical feedback strategies fails to define, in a useful way, the value of the game. A number of feedback strategy concepts have been proposed to overcome this difficulty. That of Elliot and Kalton, according to which a feedback strategy is a nonanticipative mapping between control functions for the two players, has been widely taken up because it provides a value of the game which connects, via the Hamilton-Jacobi-Isaacs equation, with other fields of systems science. Heuristic analysis of specific games problems often points to discontinuous optimal feedback strategies. These cannot be regarded as classical feedback control strategies because the associated state trajectories are not in general unique. We give general conditions under which they can be interpreted as generalized feedback strategies in the sense of Elliot and Kalton.