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Chan, Yat-fei. „Neurofuzzy network based adaptive nonlinear PID controllers“. Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43958357.
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Chan, Yat-fei, und 陳一飛. „Neurofuzzy network based adaptive nonlinear PID controllers“. Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43958357.
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3
Zickerman, Bexell Lilli. „Pressure and Level Control of a River Water Pumping Station“. Thesis, Linköpings universitet, Reglerteknik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-176998.
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The river water pumping station at SSAB in Borlänge is a critical part of the factory since it supplies the whole factory with cooling water. The problem with the river water pumping station is that the pressure in the pipes is very dependent on the large water consumers in the factory. The large consumers causes large variations in pressure and water level when they suddenly turns on and off. The second problem in the river water pumping station is that it can not pump enough water to the consumers during the warmer periods of the year. The aim of this thesis is to improve the control system in the river water pumping station by first creating a model of the system which then can be used to test a new controller. The model is verified against measurements from the real process. The results show that the developed model captures the general behavior of the system. Further analysis of the system show that a smaller pump could be the cause of the problem in the control system. In the development of the new controller the smaller pump was then removed and replaced with a larger pump. The new and old controller perform similarly when it comes to pressure and flow rate however the new controller is slightly better when taking the control signal into account because it does not make any large sudden changes.
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Gonzalez, Juan. „Spacecraft Formation Control| Adaptive PID-Extended Memory Recurrent Neural Network Controller“. Thesis, California State University, Long Beach, 2019. http://pqdtopen.proquest.com/#viewpdf?dispub=10978237.
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In today’s space industry, satellite formation flying has become a cost-efficient alternative solution for science, on-orbit repair and military time-critical missions. While in orbit, the satellites are exposed to the space environment and unpredictable spacecraft on-board disturbances that negatively affect the attitude control system’s ability to reduce relative position and velocity error. Satellites utilizing a PID or adaptive controller are typically tune to reduce the error induced by space environment disturbances. However, in the case of an unforeseen spacecraft disturbance, such as a fault in an IMU, the PID based attitude control system effectiveness will deteriorate and will not be able to reduce the error to an acceptable magnitude.
In order to address the shortcomings a PID-Extended Memory RNN (EMRNN) adaptive controller is proposed. A PID-EMRNN with a short memory of multiple time steps is capable of producing a control input that improves the translational position and velocity error transient response compared to a PID. The results demonstrate the PID-EMRNN controller ability to generate a faster settling and rise time for control signal curves. The PID-EMRNN also produced similar results for an altitude range of 400 km to 1000 km and inclination range of 40 to 65 degrees angles of inclination. The proposed PID-EMRNN adaptive controller has demonstrated the capability of yielding a faster position error and control signal transient response in satellite formation flying scenario.
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Talebian, Kousha. „Automation in anesthesia : a look at L₁ adaptive and PID controllers“. Thesis, University of British Columbia, 2016. http://hdl.handle.net/2429/60260.
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Control of anesthesia is one of the many tasks performed by anesthesiologists during surgery. It involves adjusting drug dosage by monitoring patient’s vital and clinical signs. A control system can replace this tedious and routine task, and allow the anesthesiologists to concentrate on more life threatening procedures. Because of large intra- and inter-variability in patients Pharmacokinetics and Pharmacodynamics responses, an adaptive controller is desirable. This thesis thoroughly investigates the L₁ Adaptive Control by applying it on 44 simulation cases which cover a wide range of patient demographics. It is found that the controller approaches an implantable non-adaptive LTI controller as the adaptation gain increases, echoing the results found by other researches. This loss of adaptivity is shown through examples and mathematical derivations. It is concluded that the L₁ Adaptive Control in its current form is not applicable to closed-loop control of anesthesia. As an alternative to adaptive controller, partial adaptivity in a PID controller is investigated. iControl, a PID controller designed by us, can sometimes lead to oscillation in the control signal. It is desirable to automatically detect the oscillations and tune the controller in order to remove them. A real-time oscillation detection algorithm is discussed. It detects multiple oscillations in real-time and provides their frequency, amplitude, severity and regularity. A PID auto-tuning algorithm is developed that uses the dominant frequency metrics provided by the oscillation detection algorithm to retune the controller robustly and to guarantee stability. This technique is simulated and tested on 44 cases; the gain and the phase margin in all 44 cases are within < 7% of the optimal tuning parameters of iControl.Applied Science, Faculty of
Graduate
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Kim, Sunghun. „Adaptive bug prediction by analyzing project history /“. Diss., Digital Dissertations Database. Restricted to UC campuses, 2006. http://uclibs.org/PID/11984.
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Covello, Paul Eugene. „Solving the eikonal equation on an adaptive mesh /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Rivera-Santos, Edmundo José. „Development of an adaptive PID controller for a Sawyer linear motor system“. Thesis, Massachusetts Institute of Technology, 1996. http://hdl.handle.net/1721.1/10816.
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Viswanath, Kumar. „Adaptive integrated approach to group communications in multi-hop ad-hoc networks /“. Diss., Digital Dissertations Database. Restricted to UC campuses, 2005. http://uclibs.org/PID/11984.
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Ammons, Stephen Mark. „Towards advanced study of Active Galactic Nuclei with visible light adaptive optics /“. Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.
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Vávra, Pavel. „Průmyslový regulátor PID s autotunerem a vizualizací“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2010. http://www.nusl.cz/ntk/nusl-218359.
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This thesis deals with implementation of industrial used controlling block into Power Panel equipment of B&R in integrated development environment Automation Studio 3.0.71. It is PID controller with autotuner and visualization, which allowed bumpless transfer among controlling algorithms and manual control. PID and I-PD controllers with filtering of derivative action and dynamic antiwindup were implemented. Parameters of PID controller is possible to tune with the aid of ultimate gain and ultimate period according rules of Ziegler-Nichols. Ultimate parameters of controlled plant is possible to acquire with the aid of two identification methods, recursive least squares method and relay feedback. Recursive least squares method was implemented with directional forgetting. For relay feedback were used two types of relays: ideal and saturation relay for improving accuracy of searched ultimate values. The whole solution is programmed in ANSI C which Automation Studio supports. Created controller is control with the aid of touchscreen which is integrated in Power Panel. Trends of process values are viewed on the screen too. For comparison adaptive controller by B&R was implemented. This contoller is standardly supplied with Automation Studio in LoopConR library. All created algorithms were first validated on mathematical model of plant and then on real model in laboratory. The first part of thesis deals with theoretic analysis of used methods. The practical realization is described in the second part of this diploma thesis.
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Bergman, Kristoffer, und Jonatan Ekström. „Modeling, Estimation and Attitude Control of an Octorotor Using PID and L1 Adaptive Control Techniques“. Thesis, Linköpings universitet, Reglerteknik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-107562.
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A multirotor is a type of aerial vehicle that has attracted a lot of attention in recent years. Multirotors have found applications in a variety of different fields and they are used by scientists and researchers, commercial UAV companies and radio control enthusiasts alike. In this thesis a multirotor with eight rotors, also called an octorotor, is used. A physical model of the octorotor has been developed using theory from rigid body mechanics and aerodynamics. The unknown parameters in this model have been found using several identification experiments. The model has been used for controller design and comparison in a simulation environment. An attitude estimation algorithm has been designed and implemented on the target hardware. The algorithm is referred to as a nonlinear complementary filter and it uses a quaternion rotation representation and onboard measurements to compute an estimate of the current aircraft attitude. Two different attitude controllers have been designed and evaluated. The first controller is based on PID techniques which are commonly used in multirotor flight stabilization systems. The second controller uses a novel control structure based on L1 adaptive control techniques. A baseline attitude PD controller is augmented with an L1 adaptive controller in the rate feedback loop. The two controller structures are compared using a simulation environment based on the developed model of the octorotor. The results show that the proposed structure gives a notable performance increase with respect to robustness against modeling errors and input disturbance rejection compared to the PID controller. However, the L1 adaptive controller is more complex to implement and gives less noise attenuation. The PID controller has been implemented on the platform's hardware and initial flight tests have been performed with promising results.En multirotor är en typ av flygande farkost som har fått mycket uppmärksamhet under senare år. Multirotorer tillämpas inom flertalet områden och de används av bland annat forskare och vetenskapsmän, kommersiella UAV- företag samt hobbyentusiaster. I detta examensarbete används en multirotor med åtta rotorer, en så kallad oktakopter. En fysikalisk modell av oktakoptern har tagits fram med hjälp av teori från stelkroppsmekanik och aerodynamik. De okända parametrarna i modellen har skattats med hjälp av ett flertal identifieringsexperiment. Modellen har använts för att designa och jämföra regulatorer i en simuleringsmiljö. En algoritm för att skatta farkostens attityd har designats och implementerats på oktakopterns hårdvara. Algoritmen är en variant av ett olinjärt komplementärt filter och använder en kvaternionrepresentation av attitydvinklar och uppmätt sensordata för att skatta farkostens nuvarande attityd. Två olika attitydregulatorer har designats och utvärderats. Den första regulatorn är baserad på PID-teknik vilket är vanligt för stabilisering av multirotorsystem. Den andra regulatorn använder en ny regulatorstruktur baserad på L1-adaptiv teknik. En grundregulator av PD-typ utökas med en L1-adaptiv regulator i vinkelhastighetsloopen. De två regulatorstrukturerna jämförs i en simuleringsmiljö baserad på den framtagna modellen av oktakoptern. Resultaten visar att den föreslagna regulatorstrukturen ger en betydande prestandaökning gällande robusthet mot modellfel och undertryckning av ingångsstörningar jämfört med PID-regulatorn. Dock är L1-regulatorn mer komplex att implementera och den ger mindre brusundertryckning. PID-regulatorn har implementerats på plattformens hårdvara och inledande flygtester har genomförts med lovande resultat.
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Pirabakaran, Kandasamy. „New developments in autotuning of PID controllers using model reference adaptive control and neural networks“. Thesis, University of Reading, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413896.
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Gärtner, Johan, und Philip Johansson. „AN ADAPTIVE CONTROL SYSTEM BASED ON PID, I2PD AND RLS, A SIMULATED DESIGN FOR UAVS“. Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-35614.
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During this master thesis an adaptive control system for angular velocity was developed. The approach focuses on radio controlled quadrotors and thereby targets a computational efficient solution. The adaptation is divided into two steps. First, an Integral Squared Plus Time Delay (I2PD) model estimation is done through the Recursive Least Squares (RLS) algorithm. Second, control parameters for the quadrotors Proportional Integral Derivative (PID) controller are found by using empirically modified Tuning Rules (TRs) which are based on the I2PD model. Simulation results show the benefits of an adaptive tuning algorithm in regards of the time consuming process of manually tuning a PID controller as well as robustness against both predictable and unpredictable system changes. This includes actuator degradation, battery consumption, changes in weight or inertia etc. However, it is apparent that the tuning algorithm demands an arbitrary initial approximation to be stable at initialization.
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Davis, Alison R. „Kin dynamics and adaptive benefits of social aggregation in the Desert Night Lizard, Xantusia vigilis /“. Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.
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Okpo, Juliet Airenvbiegbe. „Adaptive exercise selection for an intelligent tutoring system“. Thesis, University of Aberdeen, 2018. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=238127.
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Adapting to learner characteristics is essential when selecting exercises for learners in an intelligent tutoring system. This thesis investigates how humans adapt next exercise selection (in particular difficulty level) to learner personality (self-esteem), invested mental effort, and performance to inspire an adaptive exercise selection algorithm. First, we describe the investigations to produce validated materials for the main studies, namely the creation and validation of self-esteem personality stories, mental effort statements, and mathematical exercises with varying levels of difficulty. Next, through empirical studies, we investigate the impact on exercise selection of learner's selfesteem (low versus high self-esteem) and effort (minimal, little, moderate, much, and all possible effort). Three studies investigate this for learners who had different performances on a previous exercise: just passing, just failing, and performed well. Participants considered a fictional learner with a certain performance, self-esteem and effort, and selected the difficulty level of the next mathematical exercise. We found that self-esteem, mental effort, and performance all impacted the difficulty level of the exercises selected for learners. Using the results from the studies, we generated an algorithm that selects exercises with varying difficulty levels adapted to learner characteristics. Finally, through a survey with professional teachers, we evaluated our algorithm and found that the algorithm's adaptations were appropriate in general.
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Keller, Kaylene Elizabeth. „Landscape scale analysis of riparian restoration, site selection and adaptive management in California's Cosumnes River floodplain /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Raschke, Lynne M. „Investigating the central environments of the nearby galaxies with adaptive optics and the Hubble space telescope /“. Diss., Digital Dissertations Database. Restricted to UC campuses, 2007. http://uclibs.org/PID/11984.
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Mitra, Suman. „Zebrafish adaptive immunity : progress with defining Th-type responses and cells“. Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=165216.
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Our initial studies reported on the cloning and characterization of FoxP3 (T regulatory cell specific) for the first time in any teleost species along with T-bet and STAT6 in zebrafish, which are specific to Th1 and Th2 cells respectively and looked at their expression in the zebrafish. Our next studies focused on CD4 expression by T cells and addresses the question whether teleost Th cells are functionally similar to their mammalian counterpart. A CD4 specific antibody was developed and using molecular techniques have been able to characterise for the first time CD4+ cells within the zebrafish. In addition, to the CD4L gene, three other novel CD4 related genes have also been discovered which need to be investigated, which could mean in fish different T helper cell populations exist expressing CD4 related molecules. Another FoxP3 gene was discovered, a factor important in controlling the differentiation and function of T regulatory (Treg) cells, and so we shifted our investigations to studying these FoxP3 molecules within the zebrafish model. These two orthologs of mammalian FoxP3 were only found in zebrafish and it appears that higher vertebrates including modern fish only have one copy of the FoxP3 gene. Through the development of an antibody we were also able to look at the expression of the zebrafish genes within cells and determine where they were being expressed. Lastly, having all the molecular tools that were developed during the course of this thesis, allowed us to use in vivo zebrafish models of Mycobacterium marinum and Salmonella typhimurium infection, and attempt to determine the types of adaptive immune responses that were being developed. Understanding the regulatory mechanisms behind the teleost adaptive immune response will help to establish the zebrafish model for vertebrate immune function.
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Ferreira, Gustavo de sá. „Controle PID convencional e GPC adaptativo aplicados em um robô manipulador planar“. Universidade Federal da Paraíba, 2016. http://tede.biblioteca.ufpb.br:8080/handle/tede/8982.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The present work aims at the development and implementation of the adaptive generalized predictive controller (GPC) and the proportional integral proportional controller (PID) in a two-degree planar manipulator robot (2 GDL) composed of a rotational link and another prismatic. The rotational link has as structure an extensive branch of aluminum in profile U, having as actuator a motor-reducer of continuous current, and as sensing a potentiometer of ten turns, that acts like transducer of angular position. The prismatic link consists of a double acting pneumatic cylinder with a through rod fixed inside the rotational link, having as actuator a proportional electropneumatic valve of five paths and three positions and as sensing a potentiometric ruler that acts as a linear position transducer . The obtaining of the representative mathematical model of the robot will occur through the estimator of recursive least squares (MQR). We present experimental results of the estimated models and system responses under the action of the designed controllers.
O presente trabalho tem como objetivo o desenvolvimento e implementação do controlador preditivo generalizado (GPC) adaptativo e do controlador proporcional integral derivativo (PID) convencional, em um robô manipulador planar de dois graus de liberdade (2 GDL) composto por um elo rotacional e outro prismático. O elo rotacional possui como estrutura um ramo extenso de alumínio em perfil U, possuindo como atuador um motor-redutor de corrente contínua, e como sensoriamento um potenciômetro de dez voltas, que atua como transdutor de posição angular. O elo prismático é constituído por um cilindro pneumático de dupla ação com haste passante, fixado no interior do elo rotacional, possuindo como atuador uma válvula eletropneumática proporcional de cinco vias e três posições e como sensoriamento uma régua potenciométrica, que atua como transdutor de posição linear. A obtenção do modelo matemático representativo do robô se dará através do estimador dos mínimos quadrados recursivos (MQR). São apresentados resultados experimentais dos modelos estimados e respostas do sistema sob ação dos controladores projetados.
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Santos, Regina Lucia de Andrade dos. „Controle e monitoramento, em tempo real, de um processo de precipitação de bromelina utilizando comunicação digital fieldbus“. [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/266163.
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Orientador: Flavio Vasconcelos da SilvaDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica
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Resumo: Com o advento do sistema digital em rede (fieldbus) e a ampla divulgação das vantagens da utilização desta nova tecnologia aliada ao uso de instrumentos inteligentes, tornou-se inquestionável a melhora no desempenho e confiabilidade dos dados obtidos através deste sistema para o controle em novas plantas industriais ou em sistemas destinados à pesquisa tecnológica. Estratégias de controle clássicas, tais como o controle PID (proporcional ¿ integral ¿ derivativo), são largamente utilizadas no setor industrial devido à sua robustez e facilidade de implementação, embora limitações possam ser observadas quanto à adequação destes controladores às não-linearidades presentes nos sistemas reais. A utilização dos controladores adaptativos (baseados em parâmetros variáveis) permite tais adequações respeitando a dinâmica dos sistemas. Nas últimas décadas tem-se notado um significante aumento na aplicação da teoria de controladores avançados, entretanto, a sua utilização no setor produtivo ainda é incipiente. Apresenta-se, neste trabalho, uma automação híbrida alternativa para monitoramento, em tempo real, das variáveis de processo de um sistema para precipitação da enzima bromelina com supervisão, em tempo real, das condições do processo sob diferentes perturbações na carga, usando estratégia SISO em arquitetura de rede Fieldbus. Além disso, por se tratar de um bioprocesso, em batelada, as não linearidades e o aspecto essencialmente transiente da operação evidenciam a inevitável prioridade na aplicação dos controladores avançados, uma vez que os controladores convencionais possuem ação limitada neste tipo de sistema, garantindo a qualidade final da enzima obtida. Através dos resultados obtidos pôde-se comprovar a que ambos os controladores PID convencional e adaptativo tiveram um bom desempenho na manutenção da temperatura, porém houve um melhor desempenho com o PID adaptativo como foi observado pelos parâmetros de desempenho ITAE, overshoot e tempo de subida
Abstract: Fieldbus technology and intelligent sensors/actuators are increasingly being used in automated systems, opening up new possibilities for distributed control structures, mainly in new plants and research applications where is very important to have a flexible automation structure to different plant conditions with huge flow of information. Significant improvements have been seen in advanced controllers over the last years. However, linear PID controller is still applied extensively in industrial practice. The reason lies in its robustness and well-Known control design and implementation, although assumptions, simplifications, or lumping parameters are often made to build a mathematical model that may be far from the real situation. The behavior of most physical systems, especially bath systems, is nonlinear. Linear control may be effective for local operation, but is inadequate for controlling operations over a broad range. Adaptive controllers are nonlinear systems, which are commonly based on linear control theory. Despite many publications in the last decades illustrating advantages of adaptive controllers, this Kind of control is still not so common in industrial practice. One of reasons for the low incidence of application is relative difficulty to implement this controller. In this study, a comparative experimental design and tuning of conventional PID and adaptive PID controllers was developed for a pilot plant batch to precipitate of enzyme bromelain, using SISO strategy in fieldbus network architecture. The system was applied to the on line control of temperature of the extraction tank, involving a performance control analysis, under different load disturbances. From the results of this work, both controllers were considered suitable to control the temperature of the fedbatch tank. Nevertheless, the closed loop performance was improved under adaptive PID controller: the performance index ITAE, the overshoot and the rise time decreased.
Mestrado
Sistemas de Processos Quimicos e Informatica
Mestre em Engenharia Química
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Moncur, Wendy. „A model for the provision of adaptive eHealth information across the personal social network“. Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=167015.
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This thesis describes research into the facilitation of mediated communication of health updates and support needs across the social network, on behalf of individuals experiencing acute or chronic health problems. This led to the user-centred design, development and evaluation of a prototype software tool. Investigatory applied research was conducted with the parents of sick newborn infants who were (or had previously been) cared for in a Neonatal Unit, and their social networks of family, friends, colleagues and neighbours. The thesis makes contributions to knowledge within Social Networks, Health Informatics, Adaptive Systems and User Modelling. The user-centred research was conducted using a Grounded Theory approach, progressively focussing on developing themes. An iterative approach was taken to evaluation of the resulting theory. In the Social Networks domain, a novel, intuitive mechanism for capturing the membership and structure of an individual’s personal social network has been defined and developed, grounded in the work of evolutionary anthropologist Robin Dunbar. Use of the highly visual mechanism requires low levels of literacy and computer skills. It is cross-culturally applicable, and makes no prior assumptions about an individual’s relationships. In the domains of Health Informatics, Adaptive Systems and User Modelling, a model has been defined for adaptive information sharing across the personal social network. This model provides a number of new insights about information sharing choices made by an individual experiencing a health crisis (the ego) and their supporters (alters).
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Nkwogu, Daniel Nnaemeka. „Quality of service optimization and adaptive learning in wireless sensor actuator networks for control applications“. Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215699.
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Wireless sensor actuator networks (WSANs) are becoming a solution for the implementation of control applications. Sensors and actuators can be deployed forming a large or dense network to monitor and control physical parameters or systems. However, this comes with challenges. Reliable data transmission and real-time communication constraints are the most significant challenges in WSANs for control applications because wireless networks are characterised by harsh transmission conditions. The use of WSANs for critical control applications has not gained sufficient progress as wireless networks are perceived to be totally unreliable and hence unsuitable. This makes reliable data transmission a priority in this research. Control applications will have a number of quality of service (QoS) requirements, such as requiring a very low packet-loss rate (PLR), minimum delay and guaranteed packet delivery. The overall goal of this research is to develop a framework that ensures reliable and real-time communication within the sensor network. A totally reliable network design involves ensuring reliability in areas such as the medium access control, connectivity, scalability, lifetime, clustering and routing with trade-offs such as energy consumption, system throughput and computational complexity. In this thesis, we introduce a unique method of improving reliability and real-time communication for control applications using a link quality routing mechanism which is tied into the ZigBee addressing scheme. ZigBee routing protocols do not consider link quality when making routing decisions. The results based on common network test conditions give a clear indication of the impact on network performance for various path loss models. The proposed link quality aware routing (LQAR) showed a highly significant 20.5% improvement in network delays against the ZigBee hierarchical tree routing (HTR) protocol. There is also a 17% improvement in the PLR. We also investigate variable sampling to mitigate the effects of delay in WSANs using a neural network delay predictor and observer based control system model. Our focus on variable sampling is to determine the appropriate neural network topology for delay prediction and the impact of additional neural network inputs such as PLR and throughput. The major contribution of this work is the use of typical obtainable delay series for training the neural network. Most studies have used random generated numbers which are not a correct representation of delays actually experienced in a wireless network. In addition, results show that the use of network packet loss information improves the prediction accuracy of delay. Our results show that adequate prediction of the time-delay series using the observer based variable sampling model influences the performance of the control system model under the assumptions and stated conditions.
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Santos, Hilton Seheris da Silva. „Sintonia online de controladores PID adaptativo-ótimo via redes neuronais artificiais“. Universidade Federal do Maranhão, 2017. http://tedebc.ufma.br:8080/jspui/handle/tede/1743.
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The emergence of new industrial plants with great complexity and the need to improve the operation of existing plants has fostered the development of high performance control systems, these systems must not only meet the design specifications, such as merit figures, but also operate at minimal cost and impacts at environment. Motivated by this demand, it is presented in this dissertation the development of methods for on-line tuning of control system parameters, ie, a methodology is presented for the on-line tuning of adaptive and optimal PID controllers via Artificial Neural Networks(ANNs). The approach developed in this dissertation is based on three PID controllers parameters. [Artificial neural networks with radial base functions and Model Predictive Control (MPC). From the union of these approaches a general formulation of an Adaptive-optimal PID controller via artificial neural networks with on-line tuning was presented. The on-line tuning methodology for the ANN parameters is presented in the context of MPC, predicting plant output. For the PID controller, we proposed a modification of the standard structure in order to adapt the error function. The adjustment of the PID controller parameters and the prediction of the optimally plant output, are performed by the ANN-RBF weights adjustments. In addition, an indoor implementation of the control system were proposed for the positioning of a photovoltaic panel. The performance evaluations of the proposed system were obtained from computational experiments results that were based on mathematical models and hardware experiments, that were obtained from a reduced model of a photovoltaic panel. Finally, a comparison between the proposed methodology with the classical PID controller were performed and the proposed methodology presented to be more flexible to the insertion of new performance metrics and the results achieved from the ANN, were better than the ones obtained by the classical PID tuning, such as: Ziegler-Nichols or trial and error.
O surgimento de novas plantas industriais com grande complexidade e a necessidade de melhorar a operação das plantas já existentes tem fomentado o desenvolvimento de sistemas de controle de alto desempenho, estes sistemas devem atender não só as especificações de projeto, tal como: figuras de mérito, mas também devem operar com um custo mínimo e sem causar impactos desastrosos para o meio ambiente. Motivados por esta demanda, apresenta-se nesta dissertação o desenvolvimento de métodos para sintonia online dos parâmetros dos sistemas de controle, ie, apresenta-se uma metodologia para a sintonia online de controladores PID adaptativo e ótimo via Redes Neurais Artificiais (RNAs). A abordagem desenvolvida nesta dissertação tem base as ações dos controladores PID de três termos, redes neurais artificiais com funções de base radial e Controle preditivo baseado em modelo (MPC - Model Predictive Control), a partir da união destas abordagens elabora-se a formulação geral do controlador PID Adaptativo-Ótimo via redes neurais artificiais, com sintonia online. A metodologia de ajuste online dos parâmetros da RNA está no contexto do MPC para predição de saída da planta. Para o caso do controlador PID, tem-se a modificação da estrutura padrão com o objetivo de adaptação em função do erro. O ajuste dos termos do controlador PID e da predição da saída na planta, de forma ótima, é realizada pelo ajustes dos pesos da RNA-RBF. Além disso, apresenta-se a implementação indoor do sistema de controle desenvolvido para o posicionamento de um painel fotovoltaico. As avaliações de desempenho do sistema proposto são obtidos de resultados de experimentos computacionais que são baseados em modelos matemáticos e experimentos em hardware que são obtidos de um modelo reduzido de um painel fotovoltaico. Por fim, comparando o PID clássico com o controlador desenvolvido constatou-se que este último apresenta mais flexibilidade para inserir novas métricas de desempenho e os resultados atingidos são melhores do que os parâmetros obtidos por meio da sintonia do PID clássica, tais como: métodos de Ziegler-Nichols ou tentativa e erro
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Oliveira, Robson Moreira de. „Aplicação de controle PID não linear com ganhos baseados em perfil gaussiano aplicado a um conversor Buck“. Universidade Tecnológica Federal do Paraná, 2014. http://repositorio.utfpr.edu.br/jspui/handle/1/1574.
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CAPESEste trabalho apresenta um estudo comparativo entre técnicas de controle PID (proporcional integral e derivativo) lineares e não-lineares, aplicada a um conversor abaixador de tensão de topologia Buck. O principal objetivo desse trabalho é a comparação do desempenho das técnicas de controle PID clássico e o controle PID não linear com ganhos baseados em perfil gaussiano. Trata-se de uma técnica de controle adaptativo baseada no controle PID clássico, através de uma metodologia na qual os ganhos são obtidos a partir de uma função gaussiana, buscando obter um aumento do desempenho desse sistema. Foram realizadas simulações computacionais, onde foi feita a varredura paramétrica de cada ganho (proporcional, integral e derivativo). Os resultados alcançados comprovam a eficiência da técnica proposta.
This work presents a comparative study of linear and non-linear PID control techniques (proportional, integral and derivative) applied to a step-down voltage converter in the Buck topology. The main objective of this work is to compare the performance of classical PID control and nonlinear PID control with gains based on Gaussian-shaped functions. It is an adaptive control technique based on the classical PID control, by means of a methodology in which the gains are obtained fro a Gaussian function, aiming to obtain a performance enhancement for this system. Computer simulations were performed, where a parametric sweep on the parameters for each gain (proportional , integral and derivative) were done. The achieved results verify the efficiency of the proposed tecnique.
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Murray-Dickson, Gillian. „Spatial distribution of neutral & adaptive genetic diversity in populations of the palmate newt, Lissotriton helveticus“. Thesis, University of Aberdeen, 2011. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=183838.
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Conservation genetics theory predicts that isolated populations on the periphery of a species range will display reduced levels of genetic diversity compared to those more centrally located. Low levels of diversity can potentially compromise individual fitness and population viability among peripheral populations and so from a conservation perspective, understanding genetic structure among populations with low levels of diversity is a priority. Here I examine the levels and spatial distribution of both neutral and adaptive DNA polymorphisms across populations of the palmate newt (Lissotriton helveticus); including both island and mainland populations at the northern extent of their distribution and putative source populations from which postglacial expansion occurred. Five different classes of molecular marker were assayed: (1) mitochondrial DNA sequence variation, (2) micro satellite length variation, (3) MHC allelic diversity, (4) AFLP profiling and (5) candidate nuclear locus (sodium-calcium exchanger) allelic diversity, with an overall prediction that neutral markers will exhibit reducing diversity with increasing latitude and then from mainland to island; and that neutral diversity will be a poor predictor for adaptive diversity given the additional effects of selection on these genes. These predictions were not wholly confirmed. Mitochondrial data demonstrated that refugial populations harboured more genetic diversity than postglacial populations. Conversely, micro satellite diversity did not decline gradually with increasing latitude and insular populations were not necessarily depauperate compared to those on the mainland. Adaptive diversity was not reduced among peripheral or island populations but a signature of directional selection was detected. Lastly, genome-wide AFLP diversity was not reduced among island populations whilst no clear inference was possible from the sodium-calcium exchanger gene. There was a lack of concurrence between neutral and adaptive markers and the results are discussed in relation to the effects of micro-evolutionary processes acting in populations of varying size and isolation. The significance of these findings is discussed in relation to the long term conservation of palmate newt populations.
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Yoon, Sohye. „Studies of adaptive immune responses in zebrafish (Danio rerio), with a focus on the role of CD4+ cells“. Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=211637.
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CD4+ lymphocytes (T helper cells) play a crucial role in orchestrating adaptive immune responses. This project aims to characterise the CD4+ cells in zebrafish (Danio rerio) for a better understanding of adaptive immunity in teleost fish. I cloned three CD4 homologues, termed zfCD4 and zfCD4 related (zfCD4rel1 and zfCD4rel2), with both reported previously in other bony fish species. The zfCD4 and zfCD4rels transcripts were detected in immune organs in zebrafish and were most highly expressed in the lymphocyte population. A moderate induction of the zfCD4 and zfCD4rels (and other immune related genes) was seen in kidney, spleen and intestine after poly (I:C) injection. Two antibodies against CD4 and IFN-γ, respectively, have been validated using various immunostaining approaches for further functional studies. The CD4 positive cells ranged from 20-30% of lymphocytes in zebrafish, similar to what is seen in other vertebrates. The expression level of IFN-γ and other Th cell related genes were analysed in immunised fish following re-stimulation with antigen, revealing that in zfCD4+ lymphocytes an increased expression of cytokines and master transcript factors was seen when the same antigen was used for boosting. This is the first demonstration of Th-type responses effected by CD4+ lymphocytes in a poikilotherm. Lastly, I studied an aspect of Treg function in zebrafish, focused on a master transcription factor of Tregs, the FoxP3 gene. Knocking down FoxP3 genes in zebrafish resulted in modulated gene expression of cytokines and transcription factors associated with Th and Treg cells, providing some evidence that the immune tolerance function of Treg cells may exist in teleost fish, with some sub-functionalisation of the two FoxP3 paralogues apparent. This thesis extends our knowledge into teleost adaptive immune responses mediated by CD4+ Th cells and putative FoxP3+ Treg cells and may aid future studies using zebrafish as a model of vertebrate immune function.
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Costa, Edson Bruno Marques. „Controle pid fuzzy adaptativo com estabilidade robusta por enxame de partículas multiobjetivo“. Universidade Federal do Maranhão, 2016. http://tedebc.ufma.br:8080/jspui/handle/tede/303.
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Previous issue date: 2016-02-22Conselho Nacional de Desenvolvimento Científico e Tecnológico
An adaptive fuzzy digital PID controller design methodology via multiobjective particle swarm optimization (MOPSO) based on robust stability criterion, is proposed. The plant to be controlled is modelled considering a Takagi-Sugeno (TS) fuzzy structure from input-output experimental data, by using the fuzzy C-Means clustering algorithm (antecedent parameters estimation) and fuzzy recursive least squares algorithm (consequent parameters estimation), respectively. An adaptation mechanism was formulated as a MOPSO problem for online tuning of the fuzzy digital PID controller parameters based on the fuzzy model parameters obtained recursively and the gain and phase margins specifications. Computational results for adaptive fuzzy digital PID control of a thermal plant with time varying delay is presented to illustrate the efficiency and applicability of the proposed methodology.
Nesta dissertação é proposta uma metodologia para controle PID fuzzy adaptativo com estabilidade robusta por enxame de partículas multiobjetivo, para sistemas dinâmicos não-lineares, com atraso puro de tempo. Uma estrutura de modelo fuzzy Takagi-Sugeno é definida para representação de sistemas dinâmicos não-lineares, com atraso puro de tempo, no domínio do tempo discreto. Os parâmetros do modelo fuzzy são estimados recursivamente a partir de dados experimentais, utilizando a técnica de agrupamento fuzzy C-Means (estimação do antecedente) e mínimos quadrados recursivos fuzzy (estimação do consequente). Uma estrutura de controle PID digital fuzzy Takagi-Sugeno é definida utilizando a estratégia de compensação paralela e distribuída. Um mecanismo de adaptação é formulado como um problema de otimização por enxame de partículas multiobjetivo, para ajuste online dos parâmetros do controlador fuzzy Takagi-Sugeno baseado em critério de estabilidade robusta (especificações de margem de ganho e fase). Resultados experimentais para controle PID fuzzy adaptativo baseado em critério de estabilidade robusta de um sistema térmico com atraso puro de tempo variante é apresentado para ilustrar a eficiência e aplicabilidade da metodologia proposta.
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Gyongy, Istvan. „Phase/amplitude estimation for tuning and monitoring“. Thesis, University of Oxford, 2008. http://ora.ox.ac.uk/objects/uuid:f398b986-e8a0-403a-9118-5edae6403e00.
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The benefits of good loop tuning in the process industries have long been recognized. Ensuring that controllers are kept well-configured despite changes in process dynamics can bring energy and material savings, improved product quality as well as reduced downtime. A number of loop tuning packages therefore exist that can, on demand, check the state of a loop and adjust the controller as necessary. These methods generally apply some form of upset to the process to identify the current plant dynamics, against which the controller can then be evaluated. A simple approach to the automatic tuning of PI controllers injects variable frequency sinewaves into the loop under normal plant operation. The method employs a phase-locked loop-based device called a phase-frequency/estimation and uses 'design-point' rules, where the aim is for the Nyquist locus of the loop to pass through a particular point on the complex plane. A number of advantages are offered by the scheme: it can carry out both 'one shot' tuning and continuous adaptation, the latter even with the test signal set to a lower amplitude than that of noise. A published article is included here that extends the approach to PID controllers, with simulations studies and real-life test showing the method to work consistently well for a for a wide range of typical process dynamics, the closed-loop having a response that compares well with that produced by standard tuning rules. The associated signal processing tools are tested by applying them to the transmitter of a Coriolis mass-flow meter. Schemes are devised for the tracking and control of the second mode of measurementtube oscillation alongside the so-called 'driven mode', at which the tubes are usually vibrated, leading to useful information being made available for measurement correction purposes. Once a loop has been tuned, it is important to assess it periodically and to detect any performance losses resulting from events such as changes in process or disturbance dynamics and equipment malfunction such as faulty sensors and actuators. Motivated by the effective behaviour of the controller tuners, a loop monitor developed here, also using probing sinewaves coupled with 'design-point' ideas. In this application, the effect on the process must be minimal, so the device must work with lower still SNRs. Thus it is practical to use a fixed-frequency probing signal, together with a different tool set for tracking it. An extensive mathematical framework is developed describing the statistical properties of the signal parameter estimates, and those of the indices derived from these estimates indicating the state of the loop. The result is specific practical guidelines for the application of the monitor (e.g. for the choices of test signal amplitude and test duration). Loop monitoring itself has traditionally been carried out by passive methods that calculate various performance indicators from routine operating data. Playing a central role amongst these metrics is the Harris Index (HI) and its variants, which compare the output variance to a 'minimum achievable' figure. A key advantage of the active monitor proposed here is that it is able not only to detect suboptimal control but also to suggest how the controller should be adjusted. Moreover, the monitor’s index provides a strong indication of changes in damping factor. Through simple adjustments to the algorithm (by raising the amplitude of the test signal or adding high frequency dither to the control signal), the method can be applied even in the presence of actuator non-linearity, allowing it to identify the cause of performance losses. This is confirmed by real-life trials on a non-linear flow rig.
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Puchta, Erickson Diogo Pereira. „Controle PID gaussiano com otimização dos parâmetros das funções gaussianas usando algoritmo genético e PSO“. Universidade Tecnológica Federal do Paraná, 2016. http://repositorio.utfpr.edu.br/jspui/handle/1/2436.
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Este trabalho propõe a utilização de uma técnica de controle PID adaptativo gaussiano (GAPID) com o objetivo de aumentar o desempenho do controle PID tradicional aplicado a um conversor Buck. A função gaussiana utilizada para definir os ganhos adaptativos tem características como: é uma função suave e com derivadas suaves, possui limites inferior e superior bem definidos e possui concavidade ajustável. Pelo fato de ser uma função suave, ajuda a evitar problemas relacionados às transições abruptas dos ganhos, comumente encontradas em outros métodos adaptativos. Entretanto, não há uma metodologia algébrica para obter os ganhos adaptativos, visto que originalmente o conjunto de parâmetros do GAPID é composto por oito elementos. Para tanto, utilizaram-se técnicas como otimização através de metaheurísticas bio-inspiradas, métricas avaliativas de desempenho, alteração no método de obtenção do tempo de acomodação, com o objetivo de aumentar o desempenho deste controlador (GAPID) e obter os ganhos adaptativos. O uso do conjunto de oito elementos na otimização gerou soluções ótimas, porém, muito especializadas, levando o controlador a não se comportar bem quando as condições de operação mudam. Desta forma, é proposto um vínculo entre os parâmetros não lineares das curvas gaussianas com os parâmetros lineares do controlador PID, que demonstrou gerar soluções quase tão boas quanto com parâmetros livres e menos especializadas, com comportamento mais homogêneo face a mudanças no ponto de operação do controlador e trazendo como principal vantagem a utilização dos mesmos requisitos de projeto do PID tradicional, o que facilitaria a migração do controlador PID para o GAPID dentro da maioria das indústrias. Os resultados obtidos, tanto na simulação quanto no protótipo foram semelhantes. Isso se deve ao cuidado com a modelagem e o rigor nos procedimentos de projeto, implementados da mesma forma no modelo e no protótipo.This work proposes the use of a Gaussian adaptive PID control technique (GAPID) in order to increase the performance of the traditional PID control applied to a Buck converter. The Gaussian function used to define adaptive gains has characteristics such as; it is a smooth function with smooth derivatives, it has well defined lower and upper bounded and it has the adjustable concavity. Because it is a smooth function, it helps avoid problems related to abrupt gains transition, commonly found in other adaptive methods. However, there is no algebraic methodology to obtain the adaptive gains, since originally the GAPID parameter set consists of eight elements. Therefore, was used techniques such as optimization through bio-inspired metaheuristics, performance evaluation metrics, and change in the method to obtaining the settling-time, in order to increase the performance of this controller (GAPID) and obtain the adaptive gains. The use of the eight elements in the optimization generated optimized but very specialized solutions, causing the controller not to behave well when the operating conditions change. In this way, a link between the nonlinear parameters of the gaussian curves and the linear parameters of the PID controller was proposed, which demonstrated to generate solutions almost as good as with free and less specialized parameters, with a more homogeneous behavior in relation to changes in the operating point of the controller and bringing as a main advantage the use of the same traditional PID design requirements, which would facilitate the migration of PID controller to GAPID within most industries. The results obtained in both the simulation and the prototype were similar. This is due to careful modeling and rigor in design procedures, implemented in the same way in the model and the prototype.
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Harun, Nor Omaima. „Analysis of immune gene expression in infected and vaccinated rainbow trout Oncorhynchus mykiss with a focus on cytokines of adaptive immunity“. Thesis, University of Aberdeen, 2012. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=179564.
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The aquaculture sector is currently thriving, and has expanded to meet the demand for fish and shellfish as an alternative protein source to meat. This is especially true for high value products such as Atlantic salmon, where in Scotland salmon farming is reported to be worth> £1 billion to the national economy. Currently around 40% of farmed fish and shellfish destined for human consumption are derived from aquaculture. Therefore, a great deal of attention is paid to problems that the industry faces, with fish diseases of paramount importance. A variety of species of bacteria, viruses and parasites are common in the aquatic environment, which can result in serious diseases amongst fish stocks. As a result, ways to improve disease resistance have been the focus of much attention, with the use of vaccines considered a desirable way forward. However, other approaches are also followed, such as the use of immunostimulants to improve fish health in a more limited, non-specific way, or the use of genetic markers to allow selective breeding of important disease resistance traits. For all of these approaches more information is needed on the pathways that give rise to disease resistance in fish in different situations, to allow their manipulation or monitoring, and the studies in this thesis are directed towards this goal. Fish has been used as a model to study the evolution of vertebrate immunolity for some deacades, especially work on humoral immune responses where knowledge on antibody production has dominated much of the literature on fish immunology. In contrast, little known about specific cell-mediated immunity in fish, even though it also likely plays an important role in the immune system and disease resistance. Therefore, this thesis has been focused on analysing such responses, taking advantage of the recently discovered cytokines of adaptive immune responses in fish, which allow transcriptomic studies in particular to look at the molecules turned on during infection and after vaccination. Thus the goal of this thesis was to take advantage of some successful vaccines that exist for rainbow trout, and examine the gene expression changes that occur in vaccinated trout post-challenge with the homologus pathogen, and to try to dissect pathways that may correlate with disease resistance in this species.
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Karnati, Nareen. „Bioinspired Sinusoidal Finger Joint Synergies for a Dexterous Robotic Hand to Screw and Unscrew Objects“. University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1342458391.
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Banks, Ruth. „An investigation into putative mechanisms underlying the effects of α-tocopherol and its metabolites on the adaptive stress response in HepG2 cells“. Thesis, University of Aberdeen, 2013. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=205386.
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Genes involved in xenobiotic metabolism and antioxidant signaling are enhanced in the liver of long-lived models, suggesting that a link exists between increased stress resistance and longevity assurance. The ability of certain dietary components such as electrophiles and molecules with high redox potential to induce low-dose stimulation of the endogenous cellular adaptive response is proposed to confer increased resistance to environmental stressors, and thereby present a strategy for lifespan assurance. Recently the term ‘hormetics' was applied to dietary antioxidants possessing this activity, in particular those functioning as indirect antioxidants through the induction of stress responsive pathways. Despite recognition of vitamin E as an essential micronutrient in the diet, very little is still known about its biological role, therefore further investigation into its signaling properties and those of its metabolites are required. This thesis details an investigation into the potential role of vitamin E and its long-chain metabolites in the cellular adaptive stress response in a representative hepatic cell line (HepG2), with the purpose of identifying preliminary targets to aid further comprehension of the role of vitamin E in human health and disease. A global transcriptomic approach was used to identify genes differentially regulated by alpha-tocopherol, these included candidates involved in phase I and II xenobiotic metabolism, the cellular antioxidant response and DNA damage repair. Determination of intracellular alpha-tocopherol levels indicated that up-regulation of gene targets occurred in a concentration-dependent manner. Furthermore, this induction occurred in the presence of significantly elevated levels of short-chain metabolites, alpha-carboxymethylbutyl-hydroxychroman (CMBHC) and alpha-carboxyethyl-hydroxychroman (CEHC), suggesting that metabolism of alpha-tocopherol may be important for its signaling function in HepG2 cells. The role of long-chain metabolites of alpha-tocopherol in cellular stress responsive signaling was also investigated in HepG2 cells. The long-chain metabolites were found to alter mitochondrial metabolism in a concentration-dependent manner, and subsequently to induce components of the Nrf-2 signaling pathway suggesting that these metabolites may be potential hormetic agents, and require further investigation into their role in human health.
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Dokoupil, Jakub. „Adaptivní regulátory s principy umělé inteligence a jejich porovnání s klasickými metodami identifikace“. Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218008.
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This piece of work deals with a philosophy of design adaptive controller, which is based on knowledge of mathematical model controlled plant. This master thesis is focused on closed-loop on-line parametric identification methods. An estimation of model´s parametres is solved by two main concepts: recursive leastsquare algorithms and neural estimators. In case of least-squares algorithm the strategy of preventing the typical problems are solved here. For instance numerical stability, accurecy and restricted forgetting. Back Propagation and Marquardt- Levenberg algorithm were choosen to represent artificial inteligence. There is still a little supermacy on the side of methods based on least-squares algorithm. To compare individual algorithms the grafical interface in MATLAB/Simulink was created.
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Chen, Yuanyan. „Autonomous Unmanned Ground Vehicle (UGV) Follower Design“. Ohio University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1470951910.
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Norgren, Tommy, und Jonathan Styrud. „Non-periodic sampling schemes for control applications“. Thesis, Uppsala universitet, Signaler och System, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-154500.
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In recent years, research in the field of automation has been advancing quickly in the direction of wireless networks of sensors and actuators. This development has introduced a need to reduce the amount of communication. A number of different alternative schemes have been proposed. They are usually divided into event-triggered schemes and self-triggered ones. The main purpose of this Master's thesis was to further develop and evaluate the sesampling schemes, focusing on their needed communication. The effect on control performance by the different schemes was also taken into account. Because of the difficulty in performing a theoretical comparison, the thesis focused on evaluating the schemes in simulations and in experiments on real industrial processes. The results indicate that simply using a slower periodic scheme may reduce as much communication without losing much performance as the more flexible schemes. This would imply that investing further into the other schemes may be of waste. However, using an event-triggered scheme with improvements introduced in this report may offer some advantages when it comes to performance and simplicity in setup. Maybe more importantly, it is safer during rapidly changing conditions, which also makes it very unlikely that a slow periodic sampler would ever be implemented on a real system. The results in general are very positive with communication reductions of over 90% when using a well tuned base sampling interval and over 99% when the comparison is made to current implementations in the industry, all without significant loss of performance.
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Enbiya, Saleh A. „Automatic Control Strategies of Mean Arterial Pressure and Cardiac Output. MIMO controllers, PID, internal model control, adaptive model reference, and neural nets are developed to regulate mean arterial pressure and cardiac output using the drugs sodium Nitroprusside and dopamine“. Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/13421.
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High blood pressure, also called hypertension is one of the most common worldwide diseases afflicting humans and is a major risk factor for stroke, myocardial infarction, vascular disease, and chronic kidney disease. If blood pressure is controlled and oscillations in the hemodynamic variables are reduced, patients experience fewer complications after surgery. In clinical practice, this is usually achieved using manual drug delivery. Given that different patients have different sensitivity and reaction time to drugs, determining manually the right drug infusion rates may be difficult. This is a problem where automatic drug delivery can provide a solution, especially if it is designed to adapt to variations in the patient’s conditions.
This research work presents an investigation into the development of abnormal blood pressure (hypertension) controllers for postoperative patients. Control of the drugs infusion rates is used to simultaneously regulate the hemodynamic variables such as the Mean Arterial Pressure (MAP) and the Cardiac Output (CO) at the desired level. The implementation of optimal control system is very essential to improve the quality of patient care and also to reduce the workload of healthcare staff and costs. Many researchers have conducted studies earlier on modelling and/or control of abnormal blood pressure for postoperative patients. However, there are still many concerns about smooth transition of blood pressure without any side effect.
The blood pressure is classified in two categories: high blood pressure (Hypertension) and low blood pressure (Hypotension). The hypertension often occurred after cardiac surgery, and the hypotension occurred during cardiac surgery. To achieve the optimal control solution for these abnormal blood pressures, many methods are proposed, one of the common methods is infusing the drug related to blood pressure to maintain it at the desired level. There are several kinds of vasodilating drugs such as Sodium Nitroprusside (SNP), Dopamine (DPM), Nitro-glycerine (NTG), and so on, which can be used to treat postoperative patients, also used for hypertensive emergencies to keep the blood pressure at safety level.
A comparative performance of two types of algorithms has been presented in chapter four. These include the Internal Model Control (IMC), and Proportional-Integral-Derivative (PID) controller. The resulting controllers are implemented, tested and verified for three sensitivity patient response. SNP is used for all three patients’ situation in order to reduce the pressure smoothly and maintain it at the desire level. A Genetic Algorithms (GAs) optimization technique has been implemented to optimise the controllers’ parameters. A set of experiments are presented to demonstrate the merits and capabilities of the control algorithms. The simulation results in chapter four have demonstrated that the performance criteria are satisfied with the IMC, and PID controllers. On the other hand, the settling time for the PID control of all three patients’ response is shorter than the settling time with IMC controller.
Using multiple interacting drugs to control both the MAP and CO of patients with different sensitivity to drugs is a challenging task. A Multivariable Model Reference Adaptive Control (MMRAC) algorithm is developed using a two-input, two-output patient model. Because of the difference in patient’s sensitivity to the drug, and in order to cover the wide ranges of patients, Model Reference Adaptive Control (MRAC) has been implemented to obtain the optimal infusion rates of DPM and SNP. This is developed in chapters five and six.
Computer simulations were carried out to investigate the performance of this controller. The results show that the proposed adaptive scheme is robust with respect to disturbances and variations in model parameters, the simulation results have demonstrated that this algorithm cannot cover the wide range of patient’s sensitivity to drugs, due to that shortcoming, a PID controller using a Neural Network that tunes the controller parameters was designed and implemented. The parameters of the PID controller were optimised offline using Matlab genetic algorithm. The proposed Neuro-PID controller has been tested and validated to demonstrate its merits and capabilities compared to the existing approaches to cover wide range of patients.Libyan Ministry of Higher Education scholarship
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Enbiya, Saleh Abdalla. „Automatic control strategies of mean arterial pressure and cardiac output : MIMO controllers, PID, internal model control, adaptive model reference, and neural nets are developed to regulate mean arterial pressure and cardiac output using the drugs Sodium Nitroprusside and Dopamine“. Thesis, University of Bradford, 2013. http://hdl.handle.net/10454/13421.
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High blood pressure, also called hypertension is one of the most common worldwide diseases afflicting humans and is a major risk factor for stroke, myocardial infarction, vascular disease, and chronic kidney disease. If blood pressure is controlled and oscillations in the hemodynamic variables are reduced, patients experience fewer complications after surgery. In clinical practice, this is usually achieved using manual drug delivery. Given that different patients have different sensitivity and reaction time to drugs, determining manually the right drug infusion rates may be difficult. This is a problem where automatic drug delivery can provide a solution, especially if it is designed to adapt to variations in the patient’s conditions. This research work presents an investigation into the development of abnormal blood pressure (hypertension) controllers for postoperative patients. Control of the drugs infusion rates is used to simultaneously regulate the hemodynamic variables such as the Mean Arterial Pressure (MAP) and the Cardiac Output (CO) at the desired level. The implementation of optimal control system is very essential to improve the quality of patient care and also to reduce the workload of healthcare staff and costs. Many researchers have conducted studies earlier on modelling and/or control of abnormal blood pressure for postoperative patients. However, there are still many concerns about smooth transition of blood pressure without any side effect. The blood pressure is classified in two categories: high blood pressure (Hypertension) and low blood pressure (Hypotension). The hypertension often occurred after cardiac surgery, and the hypotension occurred during cardiac surgery. To achieve the optimal control solution for these abnormal blood pressures, many methods are proposed, one of the common methods is infusing the drug related to blood pressure to maintain it at the desired level. There are several kinds of vasodilating drugs such as Sodium Nitroprusside (SNP), Dopamine (DPM), Nitro-glycerine (NTG), and so on, which can be used to treat postoperative patients, also used for hypertensive emergencies to keep the blood pressure at safety level. A comparative performance of two types of algorithms has been presented in chapter four. These include the Internal Model Control (IMC), and Proportional-Integral-Derivative (PID) controller. The resulting controllers are implemented, tested and verified for three sensitivity patient response. SNP is used for all three patients’ situation in order to reduce the pressure smoothly and maintain it at the desire level. A Genetic Algorithms (GAs) optimization technique has been implemented to optimise the controllers’ parameters. A set of experiments are presented to demonstrate the merits and capabilities of the control algorithms. The simulation results in chapter four have demonstrated that the performance criteria are satisfied with the IMC, and PID controllers. On the other hand, the settling time for the PID control of all three patients’ response is shorter than the settling time with IMC controller. Using multiple interacting drugs to control both the MAP and CO of patients with different sensitivity to drugs is a challenging task. A Multivariable Model Reference Adaptive Control (MMRAC) algorithm is developed using a two-input, two-output patient model. Because of the difference in patient’s sensitivity to the drug, and in order to cover the wide ranges of patients, Model Reference Adaptive Control (MRAC) has been implemented to obtain the optimal infusion rates of DPM and SNP. This is developed in chapters five and six. Computer simulations were carried out to investigate the performance of this controller. The results show that the proposed adaptive scheme is robust with respect to disturbances and variations in model parameters, the simulation results have demonstrated that this algorithm cannot cover the wide range of patient’s sensitivity to drugs, due to that shortcoming, a PID controller using a Neural Network that tunes the controller parameters was designed and implemented. The parameters of the PID controller were optimised offline using Matlab genetic algorithm. The proposed Neuro-PID controller has been tested and validated to demonstrate its merits and capabilities compared to the existing approaches to cover wide range of patients.
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Hakala, Tim. „Settling-Time Improvements in Positioning Machines Subject to Nonlinear Friction Using Adaptive Impulse Control“. BYU ScholarsArchive, 2006. https://scholarsarchive.byu.edu/etd/1061.
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A new method of adaptive impulse control is developed to precisely and quickly control the position of machine components subject to friction. Friction dominates the forces affecting fine positioning dynamics. Friction can depend on payload, velocity, step size, path, initial position, temperature, and other variables. Control problems such as steady-state error and limit cycles often arise when applying conventional control techniques to the position control problem. Studies in the last few decades have shown that impulsive control can produce repeatable displacements as small as ten nanometers without limit cycles or steady-state error in machines subject to dry sliding friction. These displacements are achieved through the application of short duration, high intensity pulses. The relationship between pulse duration and displacement is seldom a simple function. The most dependable practical methods for control are self-tuning; they learn from online experience by adapting an internal control parameter until precise position control is achieved. To date, the best known adaptive pulse control methods adapt a single control parameter. While effective, the single parameter methods suffer from sub-optimal settling times and poor parameter convergence. To improve performance while maintaining the capacity for ultimate precision, a new control method referred to as Adaptive Impulse Control (AIC) has been developed. To better fit the nonlinear relationship between pulses and displacements, AIC adaptively tunes a set of parameters. Each parameter affects a different range of displacements. Online updates depend on the residual control error following each pulse, an estimate of pulse sensitivity, and a learning gain. After an update is calculated, it is distributed among the parameters that were used to calculate the most recent pulse. As the stored relationship converges to the actual relationship of the machine, pulses become more accurate and fewer pulses are needed to reach each desired destination. When fewer pulses are needed, settling time improves and efficiency increases. AIC is experimentally compared to conventional PID control and other adaptive pulse control methods on a rotary system with a position measurement resolution of 16000 encoder counts per revolution of the load wheel. The friction in the test system is nonlinear and irregular with a position dependent break-away torque that varies by a factor of more than 1.8 to 1. AIC is shown to improve settling times by as much as a factor of two when compared to other adaptive pulse control methods while maintaining precise control tolerances.
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De, Geest Dominique. „Techniques floues et neuronales pour des problèmes de régulation“. Phd thesis, INSA de Toulouse, 1995. http://tel.archives-ouvertes.fr/tel-00144065.
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Notre travail a porté principalement sur des aspects méthodologiques et sur des caractérisations expérimentales des techniques floues et neuronales, avec deux bancs d'essai: un pendule inversé et des fours industriels. Dans une première étape, nous avons travaillé sur des régulateurs flous de la première génération. Nous avons proposé une méthode pour minimiser les erreurs dues à la quantification lors des mises en œuvre avec table de décision. D'autre part, des études expérimentales ont permis d'expliquer l'amélioration de régulations floues par rapport à des régulations conventionnelles. Nous avons ainsi souligné les rôles, parfois bénéfiques, des non-linéarités liées aux interpolations ou aux saturations naturelles. Dans une deuxième étape, nous nous sommes intéressés aux structures de régulation neuronale directe, utilisant l'apprentissage spécialisé avec l'algorithme de rétropropagation. Nous avons développé une stratégie de régulation neuronale à régime glissant, automatiquement élaborée à partir d'une connaissance initiale très faible. Nous avons validé cette méthode avec des modèles simulés du pendule inversé et vérifié la possibilité de stabiliser le système réel. Dans une troisième étape, nous nous sommes penchés sur des améliorations de lois de régulation PID, par introduction de non linéarités significatives. Dans un premier temps, nous avons proposé deux méthodologies de réglage d'adaptateurs flous de PID (parfois appelés superviseurs flous), agissant à partir de la position dans le plan de phase. Une des méthodes de supervision inclut des garanties de stabilité. Dans un deuxième temps, nous avons mis en œuvre et amélioré une méthode d'auto-réglage d'un régulateur flou par un système flou, partant d'une loi de régulation floue initiale quasi-linéaire (résultant de l'application des règles d'équivalence). Des améliorations ont été apportées sur les fours par rapport à une régulation PID industrielle
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Barbosa, William de Souza. „Controle de um sistema de eletroestimulação funcional“. Universidade do Estado do Rio de Janeiro, 2014. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=8133.
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Esta Dissertação irá apresentar a utilização de técnicas de controle nãolinear,
tais como o controle adaptativo e robusto, de modo a controlar um sistema de
Eletroestimulação Funcional desenvolvido pelo laboratório de Engenharia Biomédica
da COPPE/UFRJ. Basicamente um Eletroestimulador Funcional (Functional
Electrical Stimulation FES) se baseia na estimulação dos nervos motores via
eletrodos cutâneos de modo a movimentar (contrair ou distender) os músculos,
visando o fortalecimento muscular, a ativação de vias nervosas (reinervação),
manutenção da amplitude de movimento, controle de espasticidade muscular,
retardo de atrofias e manutenção de tonicidade muscular. O sistema utilizado tem
por objetivo movimentar os membros superiores através do estímulo elétrico de
modo a atingir ângulos-alvo pré-determinados para a articulação do cotovelo. Devido
ao fato de não termos conhecimento pleno do funcionamento neuro-motor humano e
do mesmo ser variante no tempo, não-linear, com parâmetros incertos, sujeito a
perturbações e completamente diferente para cada indivíduo, se faz necessário o
uso de técnicas de controle avançadas na tentativa de se estabilizar e controlar esse
tipo de sistema. O objetivo principal é verificar experimentalmente a eficácia dessas
técnicas de controle não-linear e adaptativo em comparação às técnicas clássicas,
de modo a alcançar um controle mais rápido, robusto e que tenha um desempenho
satisfatório. Em face disso, espera-se ampliar o campo de utilização de técnicas de
controle adaptativo e robusto, além de outras técnicas de sistemas inteligentes, tais
como os algoritmos genéticos, provando que sua aplicação pode ser efetiva no
campo de sistemas biológicos e biomédicos, auxiliando assim na melhoria do
tratamento de pacientes envolvidos nas pesquisas desenvolvidas no Laboratório de
Engenharia Biomédica da COPPE/UFRJ.This dissertation will present the use of nonlinear control techniques, such as adaptive and robust control in order to design a Functional Electrical Stimulation (FES) system developed by Biomedical Engineering Laboratory at COPPE/UFRJ. Basically, a FES on the stimulation of motor nerves via skin electrodes in order to contract or stretch the muscles such that the amplitude and quality of the limbs movement can be maintained, reducing muscular atrophy as well. Consequently, the muscle strength can be improved and new neural pathways may be activated. Here, the goals of the proposed control system is to move the arm of the patient via electrical stimulation to achieve some desired trajectory related to the elbow angles of reference. Since we have a priori no deep knowledge of human neuro-motor model, the use of advanced and robust control schemes seems to be useful to stabilize this kind of systems which may be completely different for each individual, being time-varying, nonlinear, uncertain and subject to disturbances. The main objective is to experimentally verify the effectiveness of the proposed nonlinear and adaptive controllers when compared to classical ones in order to achieve faster, robust and better control performance. It is expected to spread the application of adaptive and robust controllers and other intelligent system tools, such as genetic algorithms, to the field of biological and biomedical engineering. Thus, we believe that the developed control system may help the improvement of the patients treatment involved in the research carried out by Biomedical Engineering Laboratory at COPPE/UFRJ.
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Chumacero, Polanco Erik. „Velocity sensorless control switched reluctance motors“. Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112062/document.
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Dans ce mémoire de thèse, nous présentons la conception, l'analyse de la stabilité, les simulations numériques et aussi les résultats des expérimentes concernant différents contrôleurs de vitesse mécanique du moteur à réluctance variable (MRV).Dans les deux premiers chapitres une brève description de la physique et de la construction du MRV est présenté ainsi que le problème du contrôle d'être abordé, c'est la commande de vitesse sans capteur. Il est aussi présenté l'état de l'art de ce problème et certains des solutions proposées dans d'autres travaux. On propose notre solution et on présente un petit résumé des articles scientifiques qui ont été publiés dans des magazines et des conférences.Dans le chapitre numéro trois est présenté le design du contrôleur adaptatif et sans capteur du MRV. On suppose, dans une première étape que seule la vitesse mécanique est inconnue et la stabilité exponentielle uniforme des erreurs de suivement est obtenue. Dans une deuxième étape, les conditions d'opération sont aggravées et, en plus de la vitesse, les paramètres physiques sont également supposées inconnues, la stabilité asymptotique uniforme est obtenue dans ce cas. L'estimation des paramètres du MRV est garantie grâce à la condition de persistance d'excitation. Cette commande se compose de deux boucles, une boucle interne basée sur un contrôleur de type PI2D qui est particulièrement intéressant parce qu'il est libre de modèle; cette boucle entraîne les variables mécaniques -la position et la vitesse- vers une référence désirée. Une deuxième boucle de contrôle externe prend le courant électrique vers un ' "courant de référence virtuelle" qui est généré sur la base d'une approche de partage de couple. Le contrôleur propose est testé au niveau de simulations numériques qui sont également présentés.Dans le quatrième chapitre, une nouvelle approche de modélisation du MRV est utilisée pour concevoir le contrôleur. Dans ce scénario, on suppose que l'ensemble de l'état et tous les paramètres physiques sont disponibles, cette approche est pensée pour être adapté au contrôleur basé sur observateur, recherche qui est en cours de développement. Le contrôleur est composé de deux boucles, également que celui qui a été mentionné précédemment. Ce contrôleur est sélectionné parce qu'il est approprié pour le contrôle d'équivalence vraie, qui il s'agit de remplacer les «mesures physiques» provenant d'un capteur par les «observations» provenant d'un observateur. La mise en oeuvre numérique est effectuée sur Simulink de Matlab.Enfin, dans le chapitre cinq, les résultats expérimentaux qui ont été effectués pour évaluer la performance des contrôleurs proposés -ce sont les PI2D et adaptatif PI2D pour le modèle simplifie ainsi que le PID pour le nouveau approche de modélisation- sont présentés. Dans la première partie, une brève description de la construction du banc de tests utilisé est présenté ainsi que quelques-unes caractéristiques techniques. Trois différentes profils de vitesse sont imposées à chacun des contrôleurs proposés -ce sont la tangente hyperbolique, la rampe saturée et la référence sinusoïdal- et de bonnes résultats sont obtenus en considérant que la variable contrôlée est la vitesse. Le dernier chapitre correspond aux conclusions de la recherche effectuée ainsi qu'aux travaux futursIn this thesis dissertation we present the design, stability analysis, numerical simulations and physical experiments of different controllers designed to drive the mechanical velocity of the switched reluctance motor (SRM). In the First and Second Chapters a brief description of the physics and construction of the SRM is presented, as well as the problem of control to be aboard, that is the velocity sensorless control of motors and the state of the art of this problem. The proposed solution is introduced and a summary of the published papers as well as the contribution are also presented.In the Chapter number three is presented the velocity sensorless and adaptive control of the SRM. It is assumed, in a first stage, that only mechanical velocity is unknown, uniform exponential stability of the errors is achieved in this scenario. In a second stage, conditions are stressed and in addition to the velocity, physical parameters are also assumed unknown, uniform asymptotical stability is achieved in this case and parameters estimation is guaranteed under a persistence of excitation condition. This controller consists of two loops, an internal loop based on a PI2D–type controller which is of particular interest given it is free-model; this loop drives the mechanical variables –that is position and velocity- towards a desired reference. An external control loop takes the electrical current towards a ‘’virtual” current reference which is generated based on a torque share approach. The controller is tested on numerical simulations, which are also presented.In the fourth chapter, a new approach on the modeling of the SRM is utilized to design the controller, in this scenario is assumed that the whole state and all the physical parameters are available, however this approach is thought to be suitable to observer based controller, whose ongoing research is being performed. The controller is composed by two loops, similarly to the one mentioned previously. This controller is selected because it is suitable for certainty equivalence control, that is, to substitute the “measurements” by the “observations” coming from a virtual sensor. Numerical implementation is performed on Simulink of Matlab.Finally, in the Chapter five, the experimental results carried out to evaluate the performance of the proposed controllers are presented, these are the PI2D and the adaptive PI2D controllers for the simplified model and the $PID$ controller for the novel modeling approach. In the first part, a brief description of the construction of the utilized bench is presented as well as the some technical characteristics. Three different velocity profiles were imposed to each of the overmentioned controllers –these are the so called smooth step, the saturated ramp and the sinusoidal reference- and good results, considering that the controlled variable is the velocity, were obtained. The last chapter corresponds to the conclusions of the performed research as well as to the future work
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Sá, Denis Fabrício Sousa de. „MODELOS BASEADOS EM REDES NEURAIS ARTIFICIAIS COM APLICAÇÃO EM CONTROLE INDIRETO DE TEMPERATURA“. Universidade Federal do Maranhão, 2015. http://tedebc.ufma.br:8080/jspui/handle/tede/295.
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The representation of dynamic systems or plants via mathematical models occupies an important position in control system design that allow the performance evaluation of the controller during his development stage. These models are also used as an alternative to solve the problem of the hardness or impracticability to install sensors that measure the controlled variables, the dynamic systems representations enable non-invasive measurement of these variables. As consequence the designer has an alternative way to perform adaptive and optimal sensorless control for a given process. In this dissertation is presented a proposal for control systems schemas and algorithms, based on recurrent neural networks (ANN) and Box-Jenkins models, that are dedicated to sensorless or indirect control of dynamic systems. The proposed models and algorithms are associated with the systems identification and recurrent ANN approaches. The algorithms developed for the AAN training are Backpropagation Accelerated and RLS types that are compared with classical methods and strategies to obtain it online parameters of indirect control of system for a thermal plant, where the actuator is Peltier cell. The performance the parametric models of the plant and adaptive PID digital controllers and linear quadratic regulator (DLQR) that are the main elements of the sensorless temperature control system, are evaluated by means of hybrid simulations, where the algorithms implemented in micro controllers and the plant represented by mathematical models. The performance results of the proposed sensorless control algorithms are promissory, not only, in terms of the control system performance, but also due to the reexibility to deploy it in other dynamic systems.
A representação de sistemas dinâmicos ou plantas por meio modelos matemáticos ocupa uma posição relevante no projeto de sistemas de controle, permitindo que o projetista avalie o desempenho dos controladores durante a fase de desenvolvimento do projeto. Estes modelos também são utilizados para resolver o problema da dificuldade ou impossibilidade da inserção de sensores em plantas para medição de variáveis controladas, onde os modelos viabilizam a mediação não invasiva destas variáveis, fornecendo uma alternativa para realização do controle indireto adaptativo e ótimo de um dado processo. Nesta dissertação apresenta-se o desenvolvimento de modelos propostos baseados em redes neurais artificiais recorrentes para o controle sensorless ou indireto da planta. Os modelos propostos estão associados com as abordagens de Identificação de Sistemas e de RNA's recorrentes. OS algoritmos desenvolvidos para o treinamento das RNAs são do tipo Backpropagation acelerado e RLS, que são comparados com estratégias e métodos clássicos, para obtenção online dos parâmetros do sistema de controle indireto de uma planta térmica, tendo como atuador uma célula Peltier. Para uns de avaliação de desempenho do sistema de controle indireto da planta, os modelos paramétricos e controladores digitais adaptativos do tipo PID e regulador linear quadrático (DLQR) são avaliados por meio de simulações híbridas, sendo os algoritmos dos controladores implementados em microcontroladores e a planta representada por modelos matemáticos. Os resultados apresentados são promissores, não são sentido do desempenho do sistema de controle, mas também nos custos reduzidos para seu desenvolvimento, operação e flexibilidade de aplicação em outros sistemas dinâmicos.
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Alzoni, Yarub. „Conception et réalisation d'un régulateur auto-adaptatif industrialisable“. Nancy 1, 1989. http://www.theses.fr/1989NAN10269.
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Le principe du système adaptatif réalisé consiste à prendre en compte les informations au fur et à mesure de leurs acquisitions et à les utiliser pour calculer directement les paramètres de commande sans passer par une identification du modèle mathématique proposé. On développe également une nouvelle méthode d'auto-réglage
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Kochenderfer, Mykel J. „Adaptive modelling and planning for learning intelligent behaviour“. Thesis, University of Edinburgh, 2006. http://hdl.handle.net/1842/1408.
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An intelligent agent must be capable of using its past experience to develop an understanding of how its actions affect the world in which it is situated. Given some objective, the agent must be able to effectively use its understanding of the world to produce a plan that is robust to the uncertainty present in the world. This thesis presents a novel computational framework called the Adaptive Modelling and Planning System (AMPS) that aims to meet these requirements for intelligence. The challenge of the agent is to use its experience in the world to generate a model. In problems with large state and action spaces, the agent can generalise from limited experience by grouping together similar states and actions, effectively partitioning the state and action spaces into finite sets of regions. This process is called abstraction. Several different abstraction approaches have been proposed in the literature, but the existing algorithms have many limitations. They generally only increase resolution, require a large amount of data before changing the abstraction, do not generalise over actions, and are computationally expensive. AMPS aims to solve these problems using a new kind of approach. AMPS splits and merges existing regions in its abstraction according to a set of heuristics. The system introduces splits using a mechanism related to supervised learning and is defined in a general way, allowing AMPS to leverage a wide variety of representations. The system merges existing regions when an analysis of the current plan indicates that doing so could be useful. Because several different regions may require revision at any given time, AMPS prioritises revision to best utilise whatever computational resources are available. Changes in the abstraction lead to changes in the model, requiring changes to the plan. AMPS prioritises the planning process, and when the agent has time, it replans in high-priority regions. This thesis demonstrates the flexibility and strength of this approach in learning intelligent behaviour from limited experience.
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Heyberger, Christophe. „PGD espace-temps adaptée pour le traitement de problèmes paramétrés“. Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2014. http://tel.archives-ouvertes.fr/tel-01048636.
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Cette thèse s'intéresse à la question récurrente qu'est la résolution d'un problème pour un grand nombre de configurations différentes. Malgré l'augmentation constante de la puissance de calcul que l'on connait aujourd'hui, le traitement direct d'un tel problème reste souvent hors de portée. La technique qui est développée ici est basée sur l'utilisation de la Proper Generalized Decomposition (PGD) dans le cadre de la méthode LATIN. On étudie tout d'abord la capacité de cette technique de réduction de modèle à résoudre un problème paramétré pour un espace de conception donné. Lors du traitement d'un tel problème, on génère une base réduite que l'on peut réutiliser et éventuellement enrichir en traitant un par un les problèmes correspondants aux jeux de paramètres étudiés. Le but devient alors de développer une stratégie, inspirée par la méthode " Reduced Basis ", afin d'explorer de façon rationnelle l'espace des paramètres. L'objectif étant de construire, avec le minimum de résolutions, une base réduite " complète " qui permet de résoudre tous les autres problèmes de l'espace de conception sans enrichir cette base. On commence dès lors par montrer l'existence d'une telle base complète en extrayant les informations les plus pertinentes des solutions PGD d'un problème pour tous les jeux de paramètres de l'espace de conception. On propose ensuite une stratégie rationnelle pour construire cette base complète sans la nécessité préalable de la résolution du problème pour tous les jeux de paramètres. Enfin, les performances de la méthode proposée sont illustrées sur plusieurs exemples, montrant des gains conséquents lorsque des études récurrentes doivent être menées.
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McCormick, Kellie Michelle. „The diuresis resulting from stimulation of rapidly adapting receptors in the lung by pulmonary lymphatic obstruction /“. For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2004. http://uclibs.org/PID/11984.
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48
Dennis, Matthew Gordon. „Adapting feedback to learner personality to increase motivation“. Thesis, University of Aberdeen, 2014. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=215571.
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Motivation is important for learners. As the provision of education moves increasingly towards online delivery, keeping motivation high is a key challenge. The lack of personalized approaches traditionally delivered by human tutors increases drop out rates. This thesis investigates how a conversational agent, taking the role of a virtual tutor, could deliver personalised feedback on performance to learners. It also investigates the most effective emotional support to incorporate in this feedback in order to maintain learner motivation. How learners respond to feedback depends on many factors. We focus on learner personality as our adaptation criterion, in particular Generalized Self Efficacy (GSE) and the Five Factor model (FFM). First, based on the literature, the thesis establishes how the core concepts of motivation, affective state, feedback and personality relate to one another, and discusses other research into learner motivation and feedback. Our main methodology is the User-as-Wizard method where we model how people adapt to personality in the real world when giving feedback to learners. An algorithm is then developed to encapsulate these adaptations, and is then evaluated. To achieve this, we required a way to express different learner personalities in a controlled way. Personality can be described by many models, but one of the most popular and reliably validated is the Five-Factor Model. In this model, the personality of an individual is described by a score for each of the five dimensions or 'traits'. There are numerous self-report questionnaires for these traits, indicated by a measure of agreement with certain adjectives on a scale. To express the traits at polarized levels, we produced and validated ten stories, two for each of the traits, expressing only that trait at high and low level. These stories were based on the adjectives used in the IPIP-NEO questionnaire. We also created two polarized stories for Generalized Self Efficacy. Subsequently, we investigated how people use different slants (or bias) in performance feedback, depending on learner personality. We designed two experiments, in which participants took the role of a teacher. Participants were shown the learner's personality (through the personality story) and a set of test scores on a range of topics. We provided different ways of describing the learner's performance which could result in positive, neutral or negative slants (e.g. “you are slightly below my expectations” on a score of 10% is positive, and “you are substantially below my expectations” is neutral). The type of slant was established by a focus group of experts prior to the experiments. We found some evidence that slanting was used for very low test scores for students with low GSE, and positive slanting for conscientious students who had only just failed a test. Next, we investigated supplementing slant with emotional support. A set of emotional support statements was generated and categorized. A series of five experiments was run where participants gave feedback to students with differing personality traits (using the FFM stories) and test scores. Participants could provide the same performance feedback (with associated slant) from the previous experiments, and could choose to supplement this with the validated emotional support statements. The type of emotional support given did indeed vary between different personalities (e.g. neurotic individuals with poor grades received more emotional reflection), and an algorithm was created to describe these adaptations. Finally, we ran a qualitative study with teachers and students to investigate the algorithm's effectiveness. During the course of the thesis we also developed a methodology for generating, validating and investigating the use of Emotional Support for other domains. This has already been applied in research to persuade older adults to participate in social interactions and to support Community First Responders and carers when experiencing various stressors.
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Guo, Jianglong. „Numerical and experimental study of electroadhesion to enable manufacturing automation“. Thesis, Loughborough University, 2016. https://dspace.lboro.ac.uk/2134/21718.
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Robotics and autonomous systems (RAS) have great potential to propel the world to future growth. Electroadhesion is a promising and potentially revolutionising material handling technology for manufacturing automation applications. There is, however, a lack of an in-depth understanding of this electrostatic adhesion phenomenon based on a confident electroadhesive pad design, manufacture, and testing platform and procedure. This Ph.D. research endeavours to obtain a more comprehensive understanding of electroadhesion based on an extensive literature review, theoretical modelling, electrostatic simulation, and experimental validation based on a repeatable pad design, manufacture, and testing platform and procedure.
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Nestor, Mary Catherine. „Adapting the great unknown : the evolving perception of Walter Scott“. Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230931.
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This thesis explores the legacy of Walter Scott through analysis of the adaptations of his works. It argues that remediations of Scott's novels and poetry have shaped the conception of those works in the popular imagination and resulted in an understanding of Scott's writing which overlooks it[s] complexities. In addition, it suggests that as a by-product of the process of adaptation a very small percentage of Scott's works have come to represent the whole. This thesis examines the development of the current gap between the critical rejuvenation of Scott's legacy by the scholarly community and his continued denigration in popular culture, contending that the popular remediation of Scott's works over the course of the last two centuries contributed to the formation of this gap in perception. It also poses [i.e. posits] that adaptation provided fodder for the popular notions that his writing glorifies tartanry, chivalry and pageantry, has imposed a false version of history and culture on the people of Scotland, and is best left in the category of 'boys' adventure tales'. Furthermore, this thesis interrogates claims that Scott has no relevance for contemporary readers and has become what memory theorist Ann Rigney terms the 'Great Unknown'. While adaptations from the nineteenth century have been reasonably well documented, this thesis explores not only early dramatisations of Scott's works but also a plethora of twentieth-century remediations, including film, television, comic book, mass-market science-fiction and children's adaptations, which demonstrate that popular engagement with Scott did not end with the start of the First World War. This thesis concludes that, while Scott's readership may indeed have declined from its peak in the late nineteenth century, he still maintains a place in popular consciousness and is not as greatly forgotten as some have argued.