Dissertations / Theses on the topic 'Integral feedback'

We develop and adapt absolute stability results for nonnegative Lur'e systems, that is, systems made up of linear part and a nonlinear feedback in which the state remains nonnegative for all time. This is done in both continuous and discrete time with an aim of applying these results to population modeling. Further to this, we consider forced nonnegative Lur'e systems, that is, Lur'e systems with an additional disturbance, and provide results on input-to-state stability (ISS), again in both continuous and discrete time. We provide necessary and sufficient conditions for a forced Lur'e system to have the converging-input converging-state (CICS) property in a general setting before specializing these results to nonnegative, single-input, single-output systems. Finally we apply integral control to nonnegative systems in order to control the output of the system with the key focus being on applications to population management.

This thesis tries to research the term “robust controllers”. Its aim is to compare the robustness of discrete PID controllers (Discrete Equivalent Continuous Controller, Discrete Impulse Area Invariant, Takahashi, Feed-Forward), adaptive discrete PID controllers (Discrete Impulse Area Invariant, Takahashi, Feed-Forward), optimal controllers (quadratic optimal), and adaptive optimal controllers (quadratic optimal) on chosen transfer functions. Its aim is also to check the influence of A/D and D/A converters. The aims to obtain are demarked at the beginning of the text and also there is an explanation of the term “robustness.” Later on there is a description and an approximation to each of the chosen kinds of controllers and the identification methods used in the thesis (for adaptive controllers the method of recursive least-squares was used). The Kharitonov's Theorem are made on the chosen transfer function. Next there is a description of the methods with which the robustness of the controllers will be tested. The first method is the integral criteria, particular ITAE criterion and quadratic criterion. The second one is the analysis of the generalised circle criterion. Furthermore there are various displays of the results obtained and their corresponding comments. The results obtained are graphically displayed and by means of these schemes the particular types of controllers are compared. All of the simulations and results obtained were acquired through the use of the program MATLAB- Simulink. In the end of the thesis there is an overall evaluation.

Orientador: Regiane Helena Bertagna
Resumo: A presente pesquisa tem o objetivo de analisar as percepções dos professores que fazem parte do Programa de Ensino Integral do Estado de São Paulo (PEI) e que participam da avaliação de desempenho que faz parte do PEI, denominada “Avaliação 360 graus”, colocando a educação e as relações desses profissionais sob a ótica do gerencialismo, tendo como principais objetivos a obtenção do alcance de metas na lógica do mercado empresarial. Para que isso ocorra, é necessário medir e avaliar o trabalho que é realizado pelos profissionais e se os mesmos correspondem com o perfil esperado pela escola para garantir resultados satisfatórios. Nesse contexto, a Avaliação de Desempenho, utilizada no setor administrativo, é introduzida no ambiente escolar, avaliando os professores através de um processo que, em teoria, deve colaborar com sua formação profissional, com a reflexão sobre seu trabalho e o apontamento de melhorias. A pesquisa foi desenvolvida com o aporte de referências bibliográficas tanto na área de educação quanto de administração, além dos documentos que embasam a implantação e o funcionamento do Programa de Ensino Integral do Estado de São Paulo, Programa esse que utiliza como Avaliação de Desempenho um método específico chamado de “Avaliação 360 graus”. Como foco maior dessa pesquisa, a análise do instrumento inserido no PEI se dá através das percepções de seis professores com relação ao instrumento adotado para avaliar seu desempenho e ao processo de avaliação. Os participan... (Resumo completo, clicar acesso eletrônico abaixo)
Mestre

The study of non-linear input-output maps can be summarized by three concepts: Gain, Positivity and Dissipativity. However, in order to make efficient use of these theorems it is necessary to use loop transformations and weightings, or so called ”multipliers”.The first problem this thesis studies is the feedback interconnection of a Linear Time Invariant system with a memoryless bounded and monotone non-linearity, or so called Absolute Stability problem, for which the test for stability is equivalent to show the existence of a Zames-Falb multiplier. The main advantage of this approach is that Zames–Falb multipliers can be specialized to recover important tools such as Circle criterion and the Popov criterion. Albeit Zames-Falb multipliers are an efficient way of describing non-linearities in frequency domain, the Fourier transform of the multiplier does not preserve the L1 norm. This problem has been addressed by two paradigms: mathematically complex multipliers with exact L1 norm and multipliers with mathematically tractable frequency domain properties but approximate L1 norm. However, this thesis exposes a third factor that leads to conservative results: causality of Zames-Falb multipliers. This thesis exposes the consequences of narrowing the search Zames-Falb multipliers to causal multipliers, and motivated by this argument, introduces an anticausal complementary method for the causal multiplier synthesis in [1].The second subject of this thesis is the feedback interconnection of two bounded systems. The interconnection of two arbitrary systems has been a well understood problem from the point of view of Dissipativity and Passivity. Nonetheless, frequency domain analysis is largely restricted for passive systems by the need of canonically factorizable multipliers, while Dissipativity mostly exploits constant multipliers. This thesis uses IQC to show the stability of the feedback interconnection of two non-linear systems by introducing an equivalent representation of the IQC Theorem, and then studies formally the conditions that the IQC multipliers need. The result of this analysis is then compared with Passivity and Dissipativity by a series of corollaries.

Giving grammar feedback to ESL writers is still debatable among researchers. While researchers like Truscott (1996) argue that grammar feedback does not help ESL students, others like Ferris (2001) argue that it does. Moreover, scholars debate whether the modes of feedback (written and oral versus computer) might affect student revisions. Research has been conducted on the effectiveness of different types and modes of feedback, but it is inconclusive and decontextualized. The present study addresses the effectiveness of different types and modes of feedback in the ESL writing classroom. Thirteen ESL students at a southwestern university participated, where they were required to write three papers. They were divided into two groups. Group 1 received rhetorical and grammatical feedback combined on the first paper, while Group 2 received only rhetorical feedback on that paper. On Paper 2, the order was reversed. For Paper 3, the students were re-grouped into two groups. Group 1 received rhetorical and grammar feedback combined through computer and Group 2 received it in the written mode. A mixed approach, quantitative and qualitative, was used. The frequencies of the errors and the corrections that the students made on each paper were calculated and tabulated. The students wrote journals and were interviewed regarding their reaction to the different types and modes of feedback. The study revealed rather a complex picture of how and why students use different types and modes of feedback. The students' backgrounds, their perception of writing, their writing and revision processes and their motivation affected their use of grammar feedback as well as computer feedback. Although the students did not make a lot of changes, error feedback drew their attention to their errors and made them more aware of these errors. Students did not use computer feedback successfully and they attributed that to their cultural background, attitudes, writing styles and the dynamics of computer feedback. This study suggests that training students on self-editing might help them in detecting and correcting their errors. It also suggests that we need to integrate computer feedback with other formats of feedback and to assess the students' reactions to using computer as well as the ways in which they use it. This assessment can be employed to adjust our pedagogical approaches.

In questo lavoro abbiamo analizzato due spettri nel vicino infrarosso (rest-frame visibile) di GMASS 0953, un galassia star-forming di grande massa a z~2 che ospita un nucleo galattico attivo (AGN). La nostra analisi di due set di dati realizzati dagli spettrografi GNIRS e SINFONI ha rivelato un outflow di gas ionizzato visibile dalle transizioni di [OIII]λλ4959,5007 del quale abbiamo studiato le proprietà (es. massa, tasso di espulsione) per stabilire l’impatto che l’espulsione di materiale può avere sulla galassia. Diverse osservazioni hanno infatti rivelato espulsioni di gas dalle regioni nucleari delle galassie provocate dai venti e/o dalla pressione di radiazione sprigionati dagli AGN, che possono ridurre il combustibile necessario per la nascita delle stelle, favorendo l'evoluzione passiva dei sistemi in cui gli outflow sono in atto. Tuttavia, a causa della nostra ignoranza sulla distribuzione della polvere nella galassia e sulla geometria dell’outflow, la nostre misure non ci hanno permesso di pronunciarci in maniera definitiva sull’impatto che l’espulsione di gas può avere sull’attività di formazione stellare di GMASS 0953. Parallelamente, grazie alla disponibilità di dati di spettroscopia a campo integrale (Integral Field Spectroscopy, IFS) realizzati dallo spettrografo SINFONI, abbiamo studiato la cinematica del gas ionizzato della galassia. La nostra analisi, condotta tramite un algoritmo 3D che minimizza gli effetti dovuti alla bassa risoluzione spaziale di cui possono essere affette le osservazioni IFS, ha evidenziato la presenza di un disco per il quale abbiamo derivato la curva di rotazione, che ci ha consentito di quantificare la massa dinamica di GMASS 0953. Lo studio della cinematica ha messo in risalto i limiti legati alle osservazioni spettroscopiche a campo integrale dotate di bassa risoluzione spaziale, che rende incerta la derivazione della dispersione di velocità del gas e dunque la misura del rapporto (V/σ) di una galassia.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Teletandem (TTD) é um contexto de ensino-aprendizagem em que pares de falantes de línguas diferentes trabalham de forma autônoma e colaborativa para aprenderem a língua um do outro por meio de encontros virtuais com uso da tecnologia VoIP (imagens de webcam, voz e texto). Na modalidade teletandem institucional integrado (TTDii) implementada na UNESP de São José do Rio Preto, esses encontros (ou sessões de TTD) são incorporados às aulas de língua estrangeira de um curso de graduação. O objetivo desta pesquisa é investigar como se caracteriza a avaliação por pares na modalidade oral nesse contexto. Por entender a avaliação por pares como os momentos em que há oferecimento de feedback pelo par mais competente, procura-se, mais especificamente, descrever como participantes brasileiros, alunos de licenciatura em Letras, oferecem feedback linguístico (FL) à produção oral de aprendizes de português como língua estrangeira nas sessões de TTDii. Trata-se de um estudo de caso, de natureza qualitativa e de base interpretativista. O principal instrumento de coleta de dados é a gravação de sessões orais de TTDii em 2012, 2013 e 2014. Os procedimentos de análise são: (i) transcrever verbatim a parte em que os participantes interagem em língua portuguesa das sessões orais, (ii) identificar os FL, (iii) categorizar os tipos FL oferecidos pelos participantes brasileiros, na medida do possível, de acordo com as categorias já encontradas na literatura e (iv) identificar o que desencadeou o seu aparecimento, buscando categorizar a natureza da falha linguística. Os resultados apontam que os FL encontrados, em sua maioria, se aproximam às categorias descritas pelos estudos feitos em ambientes formais de ensino, mas têm características relacionadas ao contexto em que se inserem, principalmente no que diz respeito ao oferecimento de FL de forma menos explícita, o que pode estar relacionado à preservação de face do parceiro. Além disso, os resultados apontam para uma forma diferente de FL que está relacionada à autoavaliação.
Teletandem (TTD) is a teaching-learning context in which different language speakers work in an autonomous and collaborative way to learn each other’s language through virtual meetings using VoIP technology (webcam, voice and text). In institutional integrated teletandem (iiTTD) implemented in São José do Rio Preto, these meetings (or TTD sessions) are embedded into foreign language classes of an undergraduate course. This research aims at investigating how peer assessment is characterized in oral modality in this context. We understand peer assessment as moments in which a more competent peer offers feedback. Having that in mind, we describe how Brazilian participants, Language and Literature students, offer language feedback (LF) to Portuguese as foreign language learners’ oral production in iiTTD. It is a case study of qualitative nature and interpretive basis. The main data collection instrument is the recording of iiTTD oral sessions in 2012, 2013 and 2014. Analysis procedures are: (i) oral sessions verbatim transcription of the part in which participants interact in Portuguese language, (ii) identification of LF, (iii) categorization LF types offered by Brazilian participants, as far as possible according to categories already found in literature and (iv) identification of what triggered its appearance, seeking to categorize the nature of linguistic failure. Results show that most LF found are similar to those described by studies in formal teaching environment, but they have characteristics related to the context in which they are, particularly related to offering LF in a less explicit way, which may be related to saving partner’s face. Furthermore, the results point to a different form of FL that is related to self-assessment.

Orientador: Suzi Marques Spatti Cavalari
Banca: Viviane Aparecida Bagio Furtoso
Banca: Douglas Altamiro Consolo
Resumo: Teletandem (TTD) é um contexto de ensino-aprendizagem em que pares de falantes de línguas diferentes trabalham de forma autônoma e colaborativa para aprenderem a língua um do outro por meio de encontros virtuais com uso da tecnologia VoIP (imagens de webcam, voz e texto). Na modalidade teletandem institucional integrado (TTDii) implementada na UNESP de São José do Rio Preto, esses encontros (ou sessões de TTD) são incorporados às aulas de língua estrangeira de um curso de graduação. O objetivo desta pesquisa é investigar como se caracteriza a avaliação por pares na modalidade oral nesse contexto. Por entender a avaliação por pares como os momentos em que há oferecimento de feedback pelo par mais competente, procura-se, mais especificamente, descrever como participantes brasileiros, alunos de licenciatura em Letras, oferecem feedback linguístico (FL) à produção oral de aprendizes de português como língua estrangeira nas sessões de TTDii. Trata-se de um estudo de caso, de natureza qualitativa e de base interpretativista. O principal instrumento de coleta de dados é a gravação de sessões orais de TTDii em 2012, 2013 e 2014. Os procedimentos de análise são: (i) transcrever verbatim a parte em que os participantes interagem em língua portuguesa das sessões orais, (ii) identificar os FL, (iii) categorizar os tipos FL oferecidos pelos participantes brasileiros, na medida do possível, de acordo com as categorias já encontradas na literatura e (iv) identificar o que desencadeou o seu...
Abstract: Teletandem (TTD) is a teaching-learning context in which different language speakers work in an autonomous and collaborative way to learn each other's language through virtual meetings using VoIP technology (webcam, voice and text). In institutional integrated teletandem (iiTTD) implemented in São José do Rio Preto, these meetings (or TTD sessions) are embedded into foreign language classes of an undergraduate course. This research aims at investigating how peer assessment is characterized in oral modality in this context. We understand peer assessment as moments in which a more competent peer offers feedback. Having that in mind, we describe how Brazilian participants, Language and Literature students, offer language feedback (LF) to Portuguese as foreign language learners' oral production in iiTTD. It is a case study of qualitative nature and interpretive basis. The main data collection instrument is the recording of iiTTD oral sessions in 2012, 2013 and 2014. Analysis procedures are: (i) oral sessions verbatim transcription of the part in which participants interact in Portuguese language, (ii) identification of LF, (iii) categorization LF types offered by Brazilian participants, as far as possible according to categories already found in literature and (iv) identification of what triggered its appearance, seeking to categorize the nature of linguistic failure. Results show that most LF found are similar to those described by studies in formal teaching environment, but the ...
Mestre

As futuras utilizações de sistemas de controle em automóveis seguirão a tendência de integração, através do desenvolvimento de sistemas de controle integrados capazes de coordenar as ações dos vários subsistemas que compõem o veículo. Esta coordenação e integração requerem que as integrações entre os subsistemas sejam levadas em conta já nos primeiros estágios de projeto, levando ao desenvolvimento de modelos completos de veículos. Neste sentido, o comportamento dinâmico de um veículo de quatro rodas é analisado através de técnicas de modelagem de sistemas multicorpos utilizando-se o programa ADAMS. Posteriormente, são gerados modelos lineares obtidos através do Jacobiano das equações do modelo original, resultando em uma gama de equações na forma de espaço de estados. O modelo linearizado é então submetido a vários tipos de simulações e os resultados são comparados às respostas do modelo não linear de modo a validar as aproximações lineares em diferentes condições de operação do veículo. São também desenvolvidos dois sistemas de controle de suspensão baseados em técnicas de controle ótimo como duas diferentes abordagens: um controlador skyhook que foi implementado no modelo não linear desenvolvido no ADAMS e um controle de suspensão baseado em um controlador RLQ (Regulador Linear Quadrático), com realimentação de saída que utiliza os modelos linearizados na forma de espaço de estados, sendo este último implementado através da co-simulação ADAMS/Matlab. O sistema de controle de suspensão desenvolvido é um primeiro passo na tentativa de projeto de um sistema de controle integrado do movimento.
Future applications of control in automotive vehicles will follow a trend towards system integration, leading ultimately to the development of integrated vehicle control systems capable of coordinating the action of the various subsystems. The coordination and integration of automotive vehicle subsystems require the interaction amongst the various subsystems to be taken into consideration at the control design stages, resulting in full vehicle models. Therefore, a nonlinear 10 degree of freedom model is obtained through MBS modelling techniques present in ADAMS package software. Then, a linear model is obtained by linearization of the system equations through the Jacobian facility also present in ADAMS. The resulting linearised models are simulated and their response are compared to the previous non-linear one in order to validate the linear approximations. This work also presents two distincts suspension control systems based in optimal control theory: a skyhook controler designed at ADAMS (with the non-linear vehicle model) and a LQR (Linear Quadratic Regulator) with output feedback based on the state space linear vehicle model. This last one was designed through ADAMS/Matlab co-simulation facilities. This designed suspension control is a first attempt to future developments of integrated vehicle control.

One of the most powerful and important applications that the brain accomplishes is solving the sensory "cocktail party problem:" to adaptively suppress extraneous signals in an environment. Theoretical studies suggest that the solution to the problem involves an adaptive filter, which learns to remove the redundant noise. However, neural learning is also in its infancy and there are still many questions about the stability and application of synaptic learning rules for neural computation. In this thesis, the implementation of an adaptive filter in the brain of a weakly electric fish, A. Leptorhynchus, was studied. It was found to require a cerebellar architecture that could supply independent frequency channels of delayed feedback and multiple burst learning rules that could shape this feedback. This unifies two ideas about the function of the cerebellum that were previously separate: the cerebellum as an adaptive filter and as a generator of precise temporal inputs.

碩士
國立臺灣師範大學
工業教育學系
84
The purpose of this thesis is to study the design method of output feedback integral variable structure system. Integral variable stucture system has feature of no steady state error. It suppresses the variation of parameters and external disturbance by means of designing a boundary layer, adopts a complicated control law which is not easy to operate. This thesis adopts output feedback method, takes the difference between system output and integrator output, builds a different sliding function, also raises a nonlinear continuous control law to overcome this problem.This sliding function can generate shifting sliding surface to proceed continuous sliding mode control. The time that state point reaches sliding surface will be reduced. The magnitude of nonlinear continuous control law is proportional to the distance between state point and sliding surface. The speed that state point reaches sliding surface will be accelerated. It decreases the influence of variation of parameters and external disturbance when system is in reaching mode. When state point goes into final sliding surface, it becomes small so as to alleviate the chattering phenomena in sliding mode.It gets followig conclusions by digital simulation: The hitting time is reduced. Though it makes the settling time is increased a little by continuous sliding mode, but output is asymptotically stable and no steady state error. System is more insensitive to variation of parameters and external disturbance. As for multi-input/ multi-output condition, the proposed method also can be applied.

碩士
國立中山大學
電機工程研究所
83
The Output Feedback Integral Variable Structure Control(OFIVSC) Scheme is proposed for a class of nonlinear MIMO dynamical systems. This control scheme is an extended study of Integral Variable Structure Control(IVSC), which comprises a Variable Structure Controller for system robustness, and an integral controller for zero steady state error under step input. The proposed control scheme gives not only a systematic design procedure but also the ability to deal with the heavy coupling phenomenon. Besides, an observer is employed for state estimation , so that the state variables need not be measured. A linear full order observer and a variable structure observer are introduced in this thesis, and the separation principle is also verified. Furthermore, three numerical examples are demonstrated by using computer simulation, and a practical seesaw system is applied.

碩士
國立中山大學
電機工程研究所
82
The Output Feedback Integral Variable Structure Control (OFIVSC) Scheme is proposed for robust tracking in this thesis. In fact, this is an extended study of a control scheme called Integral Variable Structure Control (IVSC). One of the major modifications is that the output of the systems is used for feedback instead of the first state variable. The other is that an variable structure observer is employed for state observation. It is also found that the separation principle is hold under the OFIVSC scheme. The effect of output measurement errors and/or disturbances on OFIVSC scheme is discussed in this thesis. This effect is analyzed through the switching function and controller design. The bounds of state estimated error is computed. Finally, three theoretical examples of OFIVSC scheme are illustrated by using computer simulation.

博士
國立交通大學
電控工程研究所
99
For linear multi-input multi-output uncertain systems with external unknown disturbances, this thesis proposed a dynamic output feedback integral sliding mode control method to stabilize the system and suppress the effect of mismatched disturbances. The advantages of sliding mode control are its simple design procedure, great robustness against matched disturbances, etc. As part of system states or outputs are only measurable, conventional output feedback sliding mode controllers involved a synthesis problem by a structural constraint and ensured the approaching and sliding condition locally. The thesis adopted an integral sliding surface to improve the controller synthesis problem, reserved inherent benefits of sliding mode control, and offered an extra degree of freedom to suppress the effect of mismatched disturbances when the system is in the sliding mode, simultaneously. For satisfying the approaching and sliding condition globally, an adaption law was added in the controller to estimate the bound of part of unknown terms. The proposed control method can be modified to apply to uncertain time-delay systems with disturbances. For state delays with a fixed and unknown delay time, combined the output feedback integral sliding mode technique with a full-order compensator can complete the dynamic controller design. Since the system is in the sliding mode, using the property of robust disturbance attenuation can derive a linear matrix inequality as a sufficient condition for the stability; this linear matrix inequality can be decomposed into two smaller algebraic Riccati inequalities by modifying the structure of compensator. Solutions to two types of inequalities can both determine parameters of sliding surface, compensator, and controller. In the case of time-varying and unknown delay time, some delay times caused the instability of system and worsened the difficulty designing the controller. The proposed structure of dynamic sliding mode control can also complete the stability analysis and control law design for systems with time-varying delay.

碩士
大同大學
電機工程學系(所)
100
For a class of uncertain nonlinear discrete-time multi-input-multi-output (MIMO) systems, this thesis presents an integral-type sliding mode control (ISMC) method to deal with the control problem. First, a robust observer is used to estimate unknown states of the controlled system. Next, the reaching condition and the sliding condition of the system behavior can be satisfied by the proposed control law based on the integral-type sliding surface. Moreover, some adaptive laws are introduced to estimate the upper bounds of the unknown uncertainties. By the Lyapunov theory, the presented integral sliding mode control not only guarantees the robust stability of the overall closed-loop system, but also achieves the precision estimation. The feasibility of the proposed method will be confirmed by computer simulation in this thesis.

碩士
國立雲林科技大學
電子工程系
106
In circuit design area, the performance of buck converter is commonly analyzed using circuit simulation tools such as Hspice or Virtuoso. However, it takes lots of time to analyze the performance of buck converter circuit in transistor level. In this paper it is using Matlab Simulink software functions to verify the design theories and analyzing the functionalities of Buck converter circuit in system level to shorten the time period of system design phase, in order to double confirm the design accuracy and verify the functionality of the Buck converter it also has been implement to Cadence Virtuoso for further analysis to ensure that using Matlab Simulink is applicable for system development and circuit design stage. With the rapid development of the electronics industry, electronic products have been made diversified and sophisticated. However, the electronic devices will not work properly without stable supply voltage. Therefore, in order to obtain a stable voltage source, there are two kinds of voltage regulator can be applied: (1) the linear regulator, (2) switching mode buck converter. In this paper, it is discussing about the switching mode buck converter using MOSFET for high speed switching device with Proportional-Integral-Derivative (PID) controller and Pulse Width Modulation (PWM) feedback system to shorten the stability time. Moreover, the buck converter with PI, PD, and PID controller was implemented to compare the performance between different controllers. In accordance with the simulation result to convince that Matlab Simulink is applicable for system development and it also is compatible with the real circuit simulation result of Cadence Virtuoso. As to the overall circuitry performance the PID controller will better than PI or PD controller. According to the simulation test result, using Matlab Simulink is workable for circuit design, the simulation result is similar with actual circuit simulation result, furthermore the functionality performance of switching mode buck converter circuit with PID Controller is better than PI Controller and PD Controller, the output ripple of this paper is 1.3mv and the percentage of output ripple is 0.005%, the functionality performance of output ripple is better than refence paper.

碩士
國立中山大學
電機工程研究所
83
The output feedback integral variable structure controller (OFIVSC) design methodology is proposed for a class of nonlinear/uncertain dynamical systems in the absence of matching conditions. Instead of regarding the known nonlinearities as uncertainties, we especially consider these known nonlinearities during the design process. It is found that the OFIVSC scheme can be used to solve the step tracking problem even though the system has a class of unmatched uncertainties and/or nonlinearities. The controller design algorithm is given first for SISO system. Then an variable structure observer is employed for state estimation, and the effects of estimate error on the controller design are analyzed. Finally, the design algorithm of SISO system is extended to the MIMO system. Several numerical examples are also demonstrated using computer simulation.

Dissertação de mestrado integrado em Engenharia Eletrónica Industrial de Computadores
Gait pathologies often produce abnormal gait patterns, affecting human mobility. Powered assistive devices, such as lower-limb exoskeletons and orthoses, are starting to complement gait rehabilitation, to actively aid or restore the abnormal gait pattern. The human motor control system starts to influence the design of bioinspired architectures for these devices, comprising the definition of distinct levels of controllers (high-, mid-, and low-level) distributed hierarchically. Low-level controllers play an important role in this architecture, ensuring time-effective assistance adaptive to user’s needs as gait speed and trajectory. The main goal with this dissertation is the development of a real-time Feedback-Error Learning (FEL) low-level control to be integrated into a bioinspired control architecture approached in a Stand-alone, Active Orthotic System - SmartOs. The FEL control was performed by means of an Artificial Neural Network (ANN) as a feedforward controller to acquire the inverse model of the assistive device, and a Proportional-Integral-Derivative (PID) feedback controller to guarantee stability and handle with disturbances. A Powered Knee Orthosis and Powered Ankle-Foot Orthosis were used as the assistive devices and a positionbased tracking assistive strategy was applied. A validation without human load and with two subjects walking in a treadmill at 0.8, 1.0 and 1.2 km/h with the two assistive devices, controlled by the Feedback-Error Learning control, was performed. The ANN took around 90 s to learn the inverse model of the assistive device, demonstrating versatility and steadiness when changes to the magnitude and speed of the input trajectory were applied. The feedback controller guaranteed stability and shown good reactions to the applied disturbances. The implemented FEL control was capable to decrease the angular position error by 15% and to eliminate 0.25 s of phase delay when compared to a solo PID controller. Thus, it proves to be a time-effective asset to control assistive powered devices. Future work addresses the validation with more subjects and different assistive strategies.
Patologias da marcha podem conduzir ao desenvolvimento de uma marcha anormal, afetando a mobilidade das pessoas. Dispositivos ativos de assistência (DAA) começam a complementar a reabilitação da marcha. Particularmente, exosqueletos ou ortóteses ativas para os membros inferiores, destacam-se na área da reabilitação da marcha. O sistema de controlo motor humano tem sido usado como inspiração para o design de arquiteturas de controlo para estes DAA, pois compreendem a definição de diferentes níveis de controladores (alto, médio e baixo) organizados hierarquicamente. Especificamente, os controladores de baixo nível têm um papel importante nesta arquitetura, devendo garantir uma assistência temporalmente eficaz adaptada às necessidades do utilizador do utilizador, como a velocidade e a trajetória da marcha. O objetivo desta dissertação é o desenvolvimento do controlo de baixo nível Feedback- Error Learning (FEL) em tempo real, inserido no sistema de controlo bioinspirado SmartOs. O controlo FEL foi realizado através de redes neuronais artificias (RNA) como um controlador de realimentação positiva para adquirir o modelo inverso da planta, e um controlador Proporcional-Integral-Derivativo (PID) como controlador de realimentação negativa, para garantir estabilidade e lidar com perturbações do sistema. Uma ortótese ativa do joelho e do tornozelo foram os DAA usados e foi aplicada uma estratégia de assistência por seguimento baseado em posição. Foram efetuadas validações sem carga e com dois sujeitos a caminhar numa passadeira a 0.8, 1.0 e 1.2 km/h, com os dois DAA, separadamente, controlados pelo controlo FEL. A RNA demorou cerca de 90 s a aprender o modelo inverso do DAA, demostrando versatilidade e estabilidade quando foram aplicadas mudanças na magnitude e velocidade da trajetória de entrada. O controlador de realimentação negativa garantiu estabilidade e conseguiu corrigir o erro quando aplicadas perturbações externas. O controlo de FEL diminui o erro de posição em 15%, eliminando o desvio de fase, quando comparado com o controlador PID. Portanto, prova ser um controlo temporalmente eficaz e vantajoso para DAA. Trabalho futuro passa pela validação com mais sujeitos e diferentes estratégias de assistência.

碩士
國立臺灣大學
工業工程學研究所
86
In this thesis we present an enhanced algorithm to integrate the functions of statistical process control and feedback control. In the statistical process control function, the Shewhart control chart is used to detect a large process deviation while the EWMAcontrol chart is used to detect a small process devia tion. In thefeedback control function, a moving average formulation is usedto update the control model and generate the recipe on a run by run basis. To v alidate the effectiveness of the proposed algorithm,Monte Carlo simulations ar e performed. Results of the simulationsshow that the enhanced algorithm is be tter than the current schemes such as a combined EWMA control chart / EWMA con trol scheme.

The observed properties of galaxies and supermassive black holes (BH) at their centers suggest that there must be a non-gravitational feedback mechanism regulating their evolution. These are the discrepancy at low and high masses between the observed stellar mass function of galaxies and that predicted by ΛCDM models, the scaling relations between the mass of BHs and the velocity dispersion, mass and luminosity of the host galaxy spheroid and the similarity between BH growth and star formation cosmic histories. Models of galaxy formation and evolution in fact routinely include feedback from active galactic nuclei (AGN) and supernovae (SNe), which can successfully reproduce the observed properties cited above. Models consider the following two types of AGN feedback: the radiative mode (or quasar mode), that operates during a luminous AGN phase through winds powered by radiation pressure, and the kinetic (or radio) mode, in which kinetic energy is released by the AGN on longer timescales through relativistic jets, which heat the surrounding halo in galaxy clusters, thus preventing cooling and further accretion on the central galaxy, and consequently further star formation. So far, the clearest observational evidence of AGN feedback comes from the kinetic mode in massive central cluster galaxies. Radiative feedback is instead more elusive, and has been recently revealed in action only in a few luminous quasars around the peak of AGN activity history (z~2), where most powerful outflows are observed. However, it is not possible to study high-z quasar outflows on small spatial scales (<100 pc), being poorly-resolved or even unresolved in observations, due to their large distances. This can lead to systematics and uncertainties in the determination of outflow properties and forces to make some assumptions on them, which further increases the uncertainties on the outflow energetics and complicates the evaluation of the impact of outflows on host galaxies and the comparison with models. On the contrary, due to their vicinity, nearby active galaxies are ideal laboratories to explore in detail outflow properties, their formation and acceleration mechanisms, as well as the effects of AGN activity on host galaxies. This work focuses on investigating the properties of outflows in nearby Seyfert galaxies, the physical conditions of the ionized gas and the interplay between nuclear activity and star formation in the galaxy, thanks to the unprecedented combination of spatial and spectral coverage provided by the integral field spectrograph MUSE at the Very Large Telescope (VLT). We introduce our optically- and X-ray selected sample of nearby Seyferts, called MAGNUM survey. We present our MUSE emission-line flux and kinematic maps of the 10 objects we have analyzed so far, including a star-forming galaxy, NGC 6810, to study the properties of a starburst outflow for comparison as well. We map the ionized gas down to spatial scales as low as ~10 pc. We find ubiquitous ionization cones and outflows with various morphologies and extensions, from a few hundred pc to several kpc. We detect peculiar kinematic features suggestive of outflows with hollow-conical structures. We also identify enhanced linewidths perpendicular to radio jets, which point to a correlation between the presence of jets and perpendicular turbulent or outflowing gas motions. We then focus on a detailed multi-wavelength study of the ionized gas and outflow, in terms of physical properties, kinematics, and ionization mechanisms, in one specific galaxy of our sample, NGC 1365, from MUSE in optical band and Chandra satellite in X-rays. Here we map a kpc-scale biconical outflow ionized by the AGN prominent in [O III], while Hα emission traces star formation in a circumnuclear ring and along the bar of the galaxy. Soft X-rays are mostly due to thermal emission from the star-forming regions, but we manage to isolate the AGN photoionized component which matches the [O III] emission from MUSE. We map the mass outflow rate of the galactic ionized outflow, which matches that of the nuclear X-ray wind and then decreases with radius. The integrated mass outflow rate, kinetic energy rate, and outflow velocity are broadly consistent with the typical relations observed in more luminous AGN. We extend our analysis to the nearby star-forming galaxy NGC 6810, whose bipolar galactic ionized outflow we map with MUSE. We determine the dominant ionization mechanism in the outflow, its density and ionization parameter, discovering the first case of star formation occurring within an outflow in an unambiguously star-forming galaxy. We finally investigate with MUSE also the kinetic AGN feedback, by studying the ionized gas enshrouding the X-ray cavity inflated by radio jets around the massive radio-galaxy 3C 317 at the center of the local cluster Abell 2052. Thanks to MUSE capabilities, by mapping the warm gas filaments enshrouding the bubble we are able to directly measure the expansion velocity of the cavity, which usually is instead assumed or derived from indirect and model-dependent methods.

Relatório da Prática de Ensino Supervisionada, Mestrado em Ensino das Artes Visuais no 3º Ciclo do Ensino Básico e no Ensino Secundário, Universidade de Lisboa, Faculdade de Belas-Artes, Instituto de Educação, 2018
O presente trabalho, desenvolvido no âmbito da unidade curricular de Iniciação à Prática Profissional IV, do Mestrado em Ensino de Artes Visuais, consiste no relatório da ação pedagógica supervisionada no Centro de Educação e Desenvolvimento Jacob Rodrigues Pereira da Casa Pia de Lisboa. Neste estágio a disciplina lecionada foi a de Desenho e a turma intervencionada pertencia ao 12º ano. Em contexto bilingue – alunos surdos e ouvintes - e sob as premissas do Ensino Integrado, a Unidade Didática “Desenhar as Vanguardas” esteve direcionada para o reforço de conteúdos respetivos ao programa de Desenho A, definido pelo Departamento do Ensino Secundário do Ministério da Educação, com o fim de melhor preparar os alunos para os Exames Nacionais de acesso ao ensino superior. O desafio lançado pelo Instituto de Avaliação Educativa, relativamente ao tema base do respetivo Exame Nacional, estava relacionado com as Vanguardas portuguesas. A ausência de motivação intrínseca e o baixo nível inter-relacional que estes alunos revelavam, não só em grande grupo como também individualmente, apontavam para barreiras comunicacionais e fatores de bloqueio ao desenvolvimento das aprendizagens e reforço de conhecimentos. Assim, era necessário aplicar estratégias que, suportadas por exercícios diferenciados e faseados (estratégias ativas), motivassem os alunos à experimentação, abordando, através de quatro Unidades de Trabalho, todos os conteúdos, num reforço das aprendizagens retidas nos dois anos anteriores. Os processos de educação de Bruner, Vygotsky e Piaget, e as sugestões estruturais e operacionais de Bloom e Arends foram a base de apoio na resolução de problemas e da operacionalização construtiva aplicada. O fluxo constante de feedback e feedforward, com base num construtivismo positivo e motivador, revelou-se de suma importância na relação professor/alunos, surdos e ouvintes, promovendo respostas a problemas comunicacionais típicos do Ensino Integrado e autonomia necessária à sobrevivência na sociedade de hoje, desencadeando os melhores valores de Cidadania.
El presente trabajo, desarrollado en el ámbito de la asignatura de Iniciación a la Práctica Profesional IV, del Master en Enseñanza de Artes Visuales, consiste en el informe de la acción pedagógica supervisada en el Centro de Educación y Desarrollo Jacob Rodrigues Pereira de la Casa Pia de Lisboa. En estas prácticas la asignatura impartida fue la de Dibujo, y la clase sobre la que se actuó pertenecía al 12º grado. En un contexto bilingüe - alumnos sordos e oyentes – y bajo las premisas de la Enseñanza Integrada, la Unidad Didáctica “Desenhar as Vanguardas” estuvo dirigida hacia el refuerzo de contenidos respectivos al programa de Dibujo A, definido por el Departamento de Enseñanza Secundaria del Ministerio de Educación, con la finalidad de preparar mejor a los alumnos para los Exámenes Nacionales de acceso a los estudios universitarios. El desafío lanzado por el Instituto de Evaluación Educativa, en relación al tema base del Examen Nacional, estaba relacionado con el movimiento vanguardista portugués. La ausencia de motivación intrínseca y el bajo nivel de las relaciones interpersonales que estos alumnos revelaron, no sólo en grupo como también individualmente, apuntaba para barreras de comunicación y factores de bloqueo, tanto al desarrollo del aprendizaje como al refuerzo de conocimientos. Fue necesario, entonces, aplicar estrategias que, afianzadas en ejercicios diferenciados y secuenciales (estrategias activas), motivasen a los alumnos a la experimentación, abordando, a través de cuatro Unidades de Trabajo, todos los contenidos, en un refuerzo de los aprendizajes retenidos en los años anteriores. Los procesos de educación de Bruner, Vygotsky y Piaget, y las sugerencias estructurales y operacionales de Bloom e Arends fueron la base de apoyo en la resolución de problemas y de la operacionalización constructiva aplicada. El fluir constante del feedback y feedforward, con base en un constructivismo positivo y motivador, se reveló de suma importancia en la relación profesor/alumnos, sordos y oyentes, promoviendo respuestas a problemas comunicacionales típicos de la Enseñanza Integrada y autonomía necesaria a la sobrevivencia en la sociedad de hoy, desencadenando los mejores valores de Ciudadanía.