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Dissertations / Theses on the topic 'Output differential'
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Chong, Kian Haur. "Self-calibrating differential output prediction logic /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/5985.
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Zhang, Peichang. "Coherent versus differential multiple-input multiple-output systems." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/376511/.
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In recent years, Multiple-Input-Multiple-Output (MIMO) techniques have attracted substantial attention due to their capability of providing spatial diversity and/or multiplexing gains. Inspired by the concept of Spatial Modulation (SM), the novel concept of Space-Time-Shift-Keying (STSK) was recently proposed, which is considered to have the following advantages: 1) STSK constitutes a generalized shift keying architecture, which is capable of striking the required trade-off between the required spatial and time diversity as well as multiplexing gain and includes SM and Space Shift Keying (SSK) as its special cases. 2) Its high degree of design-freedom, the above-mentioned flexible diversity versus multiplexing gain trade-off can be achieved by optimizing both the number and size of the dispersion matrices, as well as the number of transmit and receive antennas. 3) Similar to the SM/SSK schemes, the Inter-Antenna-Interference (IAI) may be eliminated and consequently, the adoption of single-antenna-based Maximum Likelihood (ML) detection becomes realistic in STSK schemes. In this report, our investigation can be classified into two major categories, Coherent STSK (CSTSK) and Differential STSK (DSTSK) schemes. For CSTSK, since Channel State Information (CSI) is required for data detection, Channel Estimation (CE) techniques become necessary. To be more explicit, we first briefly review the conventional Training Based CE (TBCE) and Semi-Blind CE (SBCE) schemes for the CSTSK MIMO schemes. In addition, we develop a Blockof-Bits Selection Based CE (BBSBCE) algorithm for CSTSK schemes for increasing the overall system’s throughput, while improving the accuracy of the CE. Additionally, it has been widely recognised that MIMO schemes are capable of achieving a diversity and/or multiplexing gain by employing multiple Antenna Elements (AEs) at the transmitter and/or the receiver. However, it should also noted that since MIMO systems utilize multiple RF chains, their power consumption and hardware costs become substantial. Against this background, we introduce the concept of (Antenna Selection) AS and propose a simple yet efficient AS algorithm, namely the Norm-Based Joint Transmit and Receive AS (NBJTRAS) for assisting MIMO systems. For DSTSK, since no CSI is required for differential detection schemes, it also draws our attention. However, in the absence of CE, the Conventional Differential Detection (CDD) schemes usually suffer from a 3 dB performance degradation and may exhibit an error-flow when Doppler frequency is excessive. In order to mitigate this problem, we investigate Multiple-Symbol Differential Sphere Detection (MSDSD) scheme and adopt it in our DSTSK scheme to improve the system performance, while reducing the detection complexity. Furthermore, based on our MSDSD detected DSTSK scheme, we propose a DSTSK aided Multi-User Successive Relaying aided Cooperative System (MUSRC), which is capable of supporting various number of users flexibly, while covering the conventional 50% throughput loss due to the half-duplex transmit and receive constraint of practical transceivers.
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Robson, Andrew Peter. "A third order analysis of a low temperature differential Ringbom-Stirling engine." Thesis, Edinburgh Napier University, 2007. http://researchrepository.napier.ac.uk/Output/4167.
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Rovas, Dimitrios V. (Dimitrios Vasileios) 1975. "Reduced-basis output bound methods for parametrized partial differential equations." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/16956.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.Includes bibliographical references (p. 189-200).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
An efficient and reliable method for the prediction of outputs of interest of partial differential equations with affine parameter dependence is presented. To achieve efficiency we employ the reduced-basis method: a weighted residual Galerkin-type method, where the solution is projected onto low-dimensional spaces with certain problem-specific approximation properties. Reliability is obtained by a posteriori error estimation methods - relaxations of the standard error-residual equation that provide inexpensive but sharp and rigorous bounds for the error in outputs of interest. Special affine parameter dependence of the differential operator is exploited to develop a two-stage off-line/on-line blackbox computational procedure. In the on-line stage, for every new parameter value, we calculate the output of interest and an associated error bound. The computational complexity of the on-line stage of the procedure scales only with the dimension of the reduced-basis space and the parametric complexity of the partial differential operator; the method is thus ideally suited for the repeated and rapid evaluations required in the context of parameter estimation, design, optimization, and real-time control. The theory and corroborating numerical results are presented for: symmetric coercive problems (e.g. problems in conduction heat transfer), parabolic problems (e.g. unsteady heat transfer), noncoercive problems (e.g. the reduced-wave, or Helmholtz, equation), the Stokes problem (e.g flow of highly viscous fluids), and certain nonlinear equations (e.g. eigenvalue problems).
by Dimitrios V. Rovas.
Ph.D.
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Teichman, Jeremy Alan 1975. "Bounding of linear output functionals of parabolic partial differential equations." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50440.
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Foley, Dawn Christine. "Applications of State space realization of nonlinear input/output difference equations." Thesis, Georgia Institute of Technology, 1999. http://hdl.handle.net/1853/16818.
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Paruchuri, Sai Tej. "Output Regulation of Systems Governed by Delay Differential Equations: Approximations and Robustness." Thesis, Virginia Tech, 2020. http://hdl.handle.net/10919/98409.
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This thesis considers the problem of robust geometric regulation for tracking and disturbance rejection of systems governed by delay differential equations. It is well known that geometric regulation can be highly sensitive to system parameters and hence such designs are not always robust. In particular, when employing numerical approximations to delay systems, the resulting finite dimensional models inherit natural approximation errors that can impact robustness. This demonstrates this lack of robustness and then addresses robustness by employing versions of robust regulation that have been developed for infinite dimensional systems. Numerical examples are given to illustrate the ideas and to test the robustness of the regulator.M.S.
Recent years have seen a surge in the everyday application of complex mechanical and electrical systems. These systems can perform complex tasks; however, the increased complexity makes it harder to control them. An example of such a system is a semi-autonomous car designed to stay within a designated lane. One of the most commonly used approaches for controlling such systems is called output regulation. In the above example, the output regulator regulates the output of the car (position of the car) to follow the reference output (the road lane). Traditionally, the design of output regulators assumes complete knowledge of the system. However, it is impossible to derive equations that govern complex systems like a car. This thesis analyzes the robustness of output regulators in the presence of errors in the system. In particular, the focus is on analyzing output regulators implemented to delay-differential equations. These are differential equations where the rate of change of states at the current time depends on the states at previous times. Furthermore, this thesis addresses this problem by employing the robust versions of the output regulators.
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Dang, Xiaoyu. "An Optimum Detector for Space-Time Trellis Coded Differential MSK." International Foundation for Telemetering, 2007. http://hdl.handle.net/10150/604515.
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ITC/USA 2007 Conference Proceedings / The Forty-Third Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2007 / Riviera Hotel & Convention Center, Las Vegas, NevadaThe accuracy of channel estimation plays a crucial role in the demodulation of data symbols sent across an unknown wireless medium. In this work a new analytical expression for the channel estimation error of a multiple input multiple output (MIMO) system is obtained when the wireless medium is continuously changing in the temporal domain. Numerical examples are provided to illustrate our findings. Space-time (ST) coding using Continuous Phase Modulation (CPM) has spectral advantages relative to linear modulations. In spite of the spectral benefits, Space-Time Trellis Codes (STTC) using the CPM implementation of Minimum Shift Keying (MSK) scheme has inherent inphase and quadrature interference, when the received complex baseband signal is the input into the matchfilter to remove the shaped sinusoid pulses. In this paper a novel optimum transmitting and detecting structure for STTC-MSK is proposed. Treating the Alamouti scheme as an outer code, each STTC MSK waveform frame is immediately followed by the orthogonal conjugate waveform frame at the transmit side. At the receiver first orthogonal wave forming is applied, then a new time-variant yet simple trellis structure of the STTC-MSK signals is developed. This STTC-MSK detector is absolutely guaranteed to be I/Q interference-free and still keeps a smaller computation load compared with STTC-QPSK. Simulations are made over quasi-static AWGN fading channel. It is shown that our detector for ST-MSK has solved the I/Q interference problem and has around 2.8 dB gain compared with the Alamouti Scheme and 3.8 dB gain for bit error rate at 5 X 10^(-3) in a 2 by 1 Multiple Input Single Output system.
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Chu, D., and V. Mehrmann. "Minimum Norm Regularization of Descriptor Systems by Output Feedback." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801177.
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We study the regularization problem for linear, constant coefficient descriptor
systems $E x^. = AX + Bu, y_1 = Cx, y_2=\Gamma x^.$ by proportional and derivative
mixed output feedback. Necessary and sufficient conditions are given, which guarantee
that there exist output feedbacks such that the closed-loop system is regular, has
index at most one and $E +BG\Gamma$ has
a desired rank, i.e. there is a desired number of differential and algebraic equations.
To resolve the freedom in the choice of the feedback matrices we then discuss how
to obtain the desired regularizing feedback of minimum norm and show that this approach
leads to useful results in the sense of robustness only if the rank of E is
decreased. Numerical procedures are derived to construct the desired feedbacks gains.
These numerical procedures are based on orthogonal matrix transformations which
can be implemented in a numerically stable way.
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Bondarenko, A. I., M. O. Mittsel, and A. P. Kogushko. "Laboratory stand for research of the workflow in hydrostatic mechanical transmissions." Thesis, Vela Verlag, Germany, 2014. http://repository.kpi.kharkov.ua/handle/KhPI-Press/42212.
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The work of the laboratory stand as a whole as well as its particular elements is described. The effect of
laws of parameters change of hydrostatic transmission fluid machines regulation and the laws of the
braking torque change on the basic parameters of hydrostatic mechanical transmissions of different
structures (two schemes were discussed: the first one with an inlet differential, the second - with an
output differential) at implementation of both acceleration and deceleration processes is determined. The
phenomenon of non-simultaneous translation of operating regimes of fluid machines being a part of the
hydrostatic mechanical transmission with an “output” differential in the areas of zero speed and power
modes is studied.
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Iamratanakul, Dhanakorn. "Pre-actuation and post-actuation in control applications /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/9968.
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Chembil, Palat Ramesh. "VT-STAR design and implementation of a test bed for differential space-time block coding and MIMO channel measurements." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35712.
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Next generation wireless communications require transmission of reliable high data rate services. Second generation wireless communications systems use single-input multiple-output (SIMO) channel in the reverse link, meaning one transmit antenna at the user terminal and multiple receive antennas at the base station. Recently, information theoretic research has shown an enormous potential growth in the capacity of wireless systems by using multiple antenna arrays at both ends of the link. Space-time coding exploits the spatial-temporal diversity provided by the multiple input multiple output (MIMO) channels, significantly increasing both system capacity and the reliability of the wireless link. The Virginia Tech Space-Time Advanced Radio (VT-STAR) system presents a test bed to demonstrate the capabilities of space-time coding techniques in real-time. Core algorithms are implemented on Texas Instruments TMS320C67 Evaluation Modules (EVM). The radio frequency subsystem is composed of multi-channel transmitter and receiver chains implemented in hardware for over the air transmission. The capabilities of the MIMO channel are demonstrated in a non-line of sight (NLOS) indoor environment. Also to characterize the capacity gains in an indoor environment this test bed was modified to take channel measurements. This thesis reports the system design of VT-STAR and the channel capacity gains observed in an indoor environment for MIMO channels.Master of Science
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Eftang, Jens Lohne. "Reduced Basis Methods for Partial Differential Equations : Evaluation of multiple non-compliant flux-type output functionals for a non-affine electrostatics problem." Thesis, Norwegian University of Science and Technology, Department of Mathematical Sciences, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9732.
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A method for rapid evaluation of flux-type outputs of interest from solutions to partial differential equations (PDEs) is presented within the reduced basis framework for linear, elliptic PDEs. The central point is a Neumann-Dirichlet equivalence that allows for evaluation of the output through the bilinear form of the weak formulation of the PDE. Through a comprehensive example related to electrostatics, we consider multiple outputs, a posteriori error estimators and empirical interpolation treatment of the non-affine terms in the bilinear form. Together with the considered Neumann-Dirichlet equivalence, these methods allow for efficient and accurate numerical evaluation of a relationship mu->s(mu), where mu is a parameter vector that determines the geometry of the physical domain and s(mu) is the corresponding flux-type output matrix of interest. As a practical application, we lastly employ the rapid evaluation of s-> s(mu) in solving an inverse (parameter-estimation) problem.
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Püschel, Gerhard P., Martin Oppermann, Frank Neuschäfer-Rube, Otto Götze, and Kurt Jungermann. "Differential effects of human anaphylatoxin C3a on glucose output and flow in rat liver during orthograde and retrograde perfusion : the periportal scavenger cell hypothesis." Universität Potsdam, 1991. http://opus.kobv.de/ubp/volltexte/2008/1674/.
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1) During orthograde perfusion of rat liver human anaphylatoxin C3a caused an increase in glucose and lactate output and reduction of flow. These effects could be enhanced nearly twofold by co-infusion of the carboxypeptidase inhibitor MERGETPA, which reduced inactivation of C3a to C3adesArg. 2) During retrograde perfusion C3a caused a two- to threefold larger increase in glucose and lactate output and reduction of flow than in orthograde perfusions. These actions tended to be slightly enhanced by MERGETPA. 3) The elimination of C3a plus C3adesArg immunoreactivity during a single liver passage was around 67%, irrespective of the perfusion direction and the presence of the carboxypeptidase inhibitor MERGETPA; however, less C3adesArg and more intact C3a appeared in the perfusate in the presence of MERGETPA in orthograde and retrogade perfusions
It is concluded that rat liver inactivated human anaphylatoxin C3a by conversion to C3adesArg and moreover eliminated it by an additional process. The inactivation to C3adesArg seemed to be located predominantly in the proximal periportal region of the liver sinusoid, since C3a was less effective in orthograde perfusions, when C3a first passed the proximal periportal region before reaching the predominant mass of parenchyma as its site of action, than in retrograde perfusions, when it first passed the perivenous area. These data may be evidence for a periportal scavenger mechanism, by which the liver protects itself from systemically released mediators of inflammation that interfere with the local regulation of liver metabolism and hemodynamics.
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Marx, Swann. "Méthodes de stabilisation de systèmes non-linéaires avec des mesures partielles et des entrées contraintes." Thesis, Université Grenoble Alpes (ComUE), 2017. http://www.theses.fr/2017GREAT040/document.
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Cette thèse a pour sujet la stabilisation de systèmes non-linéaires avec des mesures partielles et des entrées contraintes. Les deux premiers chapitres traitent du problème des entrées saturées dans le contexte des systèmes de dimension infinie pour des équations nonlinéaires abstraites et une équation aux dérivées partielles nonlinéaire particulière, l'équation de Korteweg-de Vries. Les outils mathématiques utilisés pour obtenir des résultats Le troisième chapitre propose une méthode de synthèse de retour de sortie pour deux équations de Korteweg-de Vries. Le quatrième chapitre concerne la synthèse d'un retour de sortie pour des systèmes non-linéaires de dimension finie pour lequel il existe un contrôle hybride. Une stratégie basée sur des observateurs grand gain est utiliséeThis thesis is about the stabilization of nonlinear systems with partial measurements and constrained input. The two first chapters deals with saturated inputs in the contex of infinite-dimensional systems for nonlinear abstract equations and for a particular partial differential equation, the Korteweg-de Vries equation. The third chapter provides an output feedback design for two Korteweg-de Vries equations using the backstepping method. The fourth chapter is about the output feedback design of nonlinear finite-dimensional systems for which there exists a hybrid controller. A high-gain observer strategy is used
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Xu, Ke. "INTELLIGENT METHODS FOR OPTIMUM ONLINE ADAPTIVE COORDINATION OF OVERCURRENT RELAYS." UKnowledge, 2018. https://uknowledge.uky.edu/ece_etds/127.
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During the operation in a modern power distribution system, some abnormal events may happen, such as over-voltage, faults, under-frequency and overloading, and so on. These abnormal events may cause a power outage in a distribution system or damages on the equipment in a distribution system. Hence these abnormal events should be identified and isolated by protection systems as quickly as possible to make sure we can maintain a stable and reliable distribution system to supply adequate electric power to the largest number of consumers as we can. To sum up, we need stable and reliable protection systems to satisfy this requirement.
Chapter 1 of the dissertation is a brief introduction to my research contents. Firstly, the background of a distribution system and the protection systems in a power system will be introduced in the first subchapter. Then there will be a review of existing methods of optimum coordination of overcurrent relays using different optimal techniques. The dissertation outline will be illustrated in the end.
Chapter 2 of the dissertation describes a novel method of optimum online adaptive coordination of overcurrent relays using the genetic algorithm. In this chapter, the basic idea of the proposed methods will be explained in the first subchapter. It includes the genetic algorithm concepts and details about how it works as an optimal technique. Then three different types of simulation systems will be used in this part. The first one is a basic distribution system without distributed generations (DGs); the second one is similar to the first one but with load variations; the last simulation system is similar to the first one but with a distributed generation in it. Using three different simulation systems will demonstrate that the coordination of overcurrent relays is influenced by different operating conditions of the distribution system.
In Chapter 3, a larger sized distribution system with more distributed generations and loads will be simulated and used for verifying the proposed method in a more realistic environment. In addition, the effects of fault location on the optimum coordination of overcurrent relays will be discussed here.
In Chapter 4, the optimal differential evolution (DE) technique will be introduced. Because of the requirement of the online adaptive function, the optimal process needs to be accomplished as soon as possible. Through the comparison between genetic algorithm and differential evolution on the optimum coordination of overcurrent relays, we found that differential evolution is much faster than the genetic algorithm, especially when the size of the distribution system grows. Therefore, the differential evolution optimal technique is more suited than the genetic algorithm to realize online adaptive function.
Chapter 5 presents the conclusion of the research work that has been done in this dissertation.
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Souza, Iderval Silva de. "Geometria do desacoplamento e integração numérica de equações diferenciais não lineares implícitas." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/3/3139/tde-19042007-161721/.
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Existem métodos de integração de equações algébrico diferenciais não lineares (DAEs) considerados clássicos pela literatura. Porém, neste trabalho, através uma abordagem geométrica, apresenta-se um método de integração de DAEs. Tal método é inspirado na teoria de desacoplamento de sistemas não lineares explícitos, quando se considera que as saídas são restrições algébricas. Neste caso, a DAE pode ser identificada como dinâmica zero. O resultado principal desta abordagem é que, dada uma DAE, sob certas condições, é possível a construção de um sistema explícito, de tal maneira, que as soluções desse sistema explícito convergem para as soluções da DAE.Classical methods for numerical integration of diferential algebraic equations (DAEs) can be formal in the literature. In this work, using a diferential geometric approach, a numerical method of integration of DAEs is established. This method is inspired in the decoupling theory of nonlinear explicit systems, when one considers that the outputs are algebraic constraints. The main result is the construction of an explicit system, whose solutions converge to the solutions of the DAE.
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Pisár, Peter. "Metody návrhu aktivních kmitočtových filtrů na základě pasivního RLC prototypu." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218107.
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The aim of this diploma thesis is to design active frequency filters based on passive RLC prototype. Three methods of the design of active filters and active functional blocks of electronic circuits working in current or mixed mode are used to this purpose. These blocks allow to process electrical signals with frequencies up to low tens of megahertz. In addition they feature for instance with high slew rate and low supply voltage power. Active high-pass and low-pass 2nd order filters are designed using simulation of inductor by active subcircuit method. Grounded and subsequently floating synthetic inductor is made with the current conveyors in the first case and with the current operational amplifiers with single input and differential output in the second case. This method advantage is relatively simple design and disadvantage is great quantity of active functional blocks. Active filters based on passive frequency ladder 3rd order filter while only one floating inductor is connected, are designed with circuit equation method. In the first design differential input / output current followers are used and in the second case current-differencing buffered amplifiers are used. This method benefits by smaller active blocks number and disadvantage is more complex design of the active filter. Active filter based on passive prototype of low-pass 3rd order filter with two floating inductors is designed with Bruton transformation method. Final active filter uses current operational amplifiers with single input and differential output which together with other passive elements replace frequency depending negative resistor, which arise after previous Bruton transform. This method usage is advantageous if the design consists of larger quantity of inductors and less number of capacitors. High-pass 2nd order filter is simulated by tolerance and parametrical analyses. Physical realisation utilising current feedback operational amplifier which substitute commercially hardly accessible current conveyors is subsequently made. Measurements of constructed active filter show that additional modifications, which allow better amplitude frequency characteristics conformity, are necessary.
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Vailong, Hubert J. B. (Hubert Jean Bernard). "A posteriori bounds for linear functional outputs of hyperbolic partial differential equations." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/46460.
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Sert, Hugues. "De l’utilisation de l’algèbre différentielle pour la localisation et la navigation de robots mobiles autonomes." Thesis, Ecole centrale de Lille, 2013. http://www.theses.fr/2013ECLI0002/document.
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Ce travail étudie l'apport de l'algèbre différentielle à deux problématiques principales de la robotique mobile à roues, la localisation et la navigation. La première problématique consiste à être capable de dire où le robot se situe dans son environnement. Nous supposons ici que nous possédons un certain nombre de points d'intérêt de l'espace dont les coordonnées dans cette espace sont connues. En fonction du nombre de points d'intérêt, il est possible ou non de localiser le robot. Cette notion de localisabilité est définie et étudiée dans le cadre algébrique. Nous montrons que ce cadre d'étude est plus intéressant que le cadre géométrique en ce sens que non seulement il permet l'étude de la localisabilité mais en plus il permet de construire des estimateurs d'états permettant de reconstruire la posture du robot. Cette étude est effectuée dans cinq cas d'études pour quatre des cinq classes de robots mobiles à roues. La deuxième problématique étudiée est celle de la navigation d'une flottille décentralisée de robots dans un environnement complexe. Ce travail présente une architecture pouvant être utilisée dans une large classe de problème et bénéficiant des avantages des approches discrètes et des approches continues. En effet, à haut niveau, un bloc stratégie spécifie l'objectif, les contraintes et leurs paramètres ainsi que la fonction coût utilisée, à bas niveau, une trajectoire est calculée afin de minimiser la fonction coût en respectant l'objectif et les contraintes du problème. Cette minimisation est faite sur un horizon glissant de manière à pouvoir prendre en compte des modifications de l'environnement ou de la mission en cours de navigationThis work investigates the contribution of differential algebra to two main issues of wheel mobile robotics, localization and navigation. The first issue is to be able to tell where the robot is in its environment. We assume that we have a number of landmarks in space whose coordinates are known in this area. Depending on the number of landmarks, it is possible or not to localize the robot. This notion of localizability is defined and studied in the algebraic framework. We show that this framework is more interesting than the geometric framework in the sense that it not only allows the study of localizability, but it also allows us to construct estimators states to reconstruct the posture of the robot. This study was conducted in five cases study for four of the five classes of wheeled mobile robots. The second problem studied is that of a robot decentralized swarm navigation in a complex environment. This work presents an architecture that can be used in a wide class of problems and enjoying the benefits of discrete approaches and continuous approaches. Indeed, high-level block strategy specifies the goal, constraints and parameters as well as the cost function, a low-level block is used to compute a trajectory that minimize the cost function in accordance with the objective and the problem constraints. This minimization is done on a sliding window so it is possible to take changes in the environment or mission during navigation into account
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Sauer-Budge, Alexander M. (Alexander Michael) 1972. "Computing upper and lower bounds on linear functional outputs from linear coercive partial differential equations." Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/30014.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2003.Includes bibliographical references (p. 115-123).
Uncertainty about the reliability of numerical approximations frequently undermines the utility of field simulations in the engineering design process: simulations are often not trusted because they lack reliable feedback on accuracy, or are more costly than needed because they are performed with greater fidelity than necessary in an attempt to bolster trust. In addition to devitalized confidence, numerical uncertainty often causes ambiguity about the source of any discrepancies when using simulation results in concert with experimental measurements. Can the discretization error account for the discrepancies, or is the underlying continuum model inadequate? This thesis presents a cost effective method for computing guaranteed upper and lower bounds on the values of linear functional outputs of the exact weak solutions to linear coercive partial differential equations with piecewise polynomial forcing posed on polygonal domains. The method results from exploiting the Lagrangian saddle point property engendered by recasting the output problem as a constrained minimization problem. Localization is achieved by Lagrangian relaxation and the bounds are computed by appeal to a local dual problem. The proposed method computes approximate Lagrange multipliers using traditional finite element discretizations to calculate a primal and an adjoint solution along with well known hybridization techniques to calculate interelement continuity multipliers. At the heart of the method lies a local dual problem by which we transform an infinite-dimensional minimization problem into a finite-dimensional feasibility problem.
(cont.) The computed bounds hold uniformly for any level of refinement, and in the asymptotic convergence regime of the finite element method, the bound gap decreases at twice the rate of the H¹-norm measure of the error in the finite element solution. Given a finite element solution and its output adjoint solution, the method can be used to provide a certificate of precision for the output with an asymptotic complexity that is linear in the number of elements in the finite element discretization. The complete procedure computes approximate outputs to a given precision in polynomial time. Local information generated by the procedure can be used as an adaptive meshing indicator. We apply the method to Poisson's equation and the steady-state advection-diffusion-reaction equation.
by Alexander M. Sauer-Budge.
Ph.D.
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Urbánek, Radim. "Frekvenční charakteristiky." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2007. http://www.nusl.cz/ntk/nusl-412762.
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The aim of this MSc Thesis is to create a system for automatic generation of frequency characteristics of electrical circuits. These circuits are described by differential equations. A special simulator of RLC circuit has been created and frequence response, vector diagram can be generated. This system has been mainly suggested for application in education. The process of solving differential equations is based on the Taylor method. Systems in general is the theoretical part of this project. Different definitions of systems their divission ,basic phenomenons and mathematical devices are described there. Next chapter deals with the mathematical devices for solving differential equations which makes the basis for description of phenomenons in these systems. There are also systems TKSL and TKSL/C. In the next chapter I was investigaty the analyze of vector diagrams for simple and more difficult circuits. I have found a solution for actual circuit by this technique. The last chapter is devoted to the frequency characteristics and descriptions of simulation program for generation the frequency characteristics.
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Rammal, Rim. "Caractérisation des sorties plates pour le diagnostic de systèmes entiers ou non entiers : application pour le diagnostic d’un système hydraulique et d’un système thermique." Thesis, Bordeaux, 2021. http://www.theses.fr/2021BORD0021.
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La platitude différentielle est une propriété des systèmes dynamiques qui permet la transformation d'un système très complexe en un système plus simple appelé système plat.On dit qu'un système dynamique est plat si, et seulement si, il existe un vecteur, appelé vecteur de sortie plate et formé par les variables d'état et d'entrée du système, tel que tous les états, entrées et sorties du système peuvent être exprimés en fonction de ce nouveau vecteur et de ses dérivées temporelles successives. La platitude différentielle a de nombreuses applications dans la théorie du contrôle automatique, telles que la planification des trajectoires, le suivi des trajectoires et la conception de contrôleurs robustes. De plus, la propriété de platitude est récemment entrée dans le domaine de la détection et de l'isolation des défauts. En bref, la détection et l'isolation des défauts sont un sous-domaine de l'ingénierie de contrôle automatique qui traite de la surveillance d'un système, de l'identification du moment où un défaut s'est produit, et de la détermination du type de défaut et de sa localisation. La détection des défauts est effectuée en analysant la différence entre les mesures des capteurs et des actionneurs et les valeurs attendues, dérivées de n'importe quel modèle et appelées valeurs redondantes. Il est courant de dire qu'une erreur est détectée si l'écart ou le résidu dépasse un certain seuil prédéfini. L'isolation des défauts, à son tour, doit permettre de localiser le défaut dans la machine. La méthode la plus récente de détection et d'isolation des défauts, basée sur la propriété de la platitude, calcule des variables redondantes à partir de la mesure de la sortie plate du système et de ses dérivées temporelles successives. Ensuite, des résidus sont déduits de la différence entre les variables mesurées et les variables redondantes. La détection des défauts par cette méthode est garantie. Cependant, l'utilisation d'une seule sortie plate ne permet pas, dans certains cas, d'isoler certains défauts. L'idée proposée par les développeurs de la méthode était d'utiliser plusieurs sorties plates pour augmenter le nombre de résidus, ce qui augmenterait les chances d'isoler davantage de défauts. Cependant, il a également été remarqué que le choix de ces sorties plates n'est pas arbitraire. En d'autres termes, il existe des sorties plates qui, lorsqu'elles sont utilisées ensemble, augmentent l'isolabilité des défauts et d'autres qui ne le font pas. Un des objectifs de ce manuscrit est de caractériser les sorties plates afin d'obtenir une meilleure isolabilité des défauts. Cette caractérisation est ensuite vérifiée par des simulations et des expériences sur un système hydraulique, le système des trois cuves.Au cours de la dernière décennie, de nombreuses études ont montré qu'il existe des systèmes tels que les systèmes thermiques, les systèmes viscoélastiques et les systèmes chimiques qui peuvent être modélisés par des équations différentielles fractionnaires. Par conséquent, les méthodes classiques de détection et d'isolation des défauts, développées à l'origine pour traiter les systèmes d'ordre entier, ne convenaient pas aux systèmes d'ordre fractionnaire, et des méthodes de détection et d'isolation des défauts spécifiques aux systèmes d'ordre fractionnaire ont dû être développées. Un deuxième objectif de ce manuscrit est d'étendre la caractérisation des sorties plates, proposée pour la classe des systèmes plats d'ordre entier à la classe des systèmes plats linéaires d'ordre fractionnaire, puis d'appliquer cette caractérisation à la détection et à l'isolation des défauts qui peuvent apparaitre sur les capteurs et les actionneurs de ces systèmes. L'efficacité de cette caractérisation est également vérifiée par des simulations sur un système thermique bi-dimensionnelThe differential flatness is a property of dynamic systems that allows the transformation of a very complex system into a simpler one called flat system. Roughly speaking, a dynamic system is said to be flat if, and only if, there exists a vector, called flat output vector and formed by the state and input variables, such that all the system states, inputs and outputs can be expressed in function of this new vector and its successive time derivatives. The differential flatness property has many applications in automatic control theory, such as trajectory planning, trajectory tracking and the designing of robust controllers. Moreover, the flatness property has recently entered the field of fault detection and isolation. In short, fault detection and isolation is a sub-domain of automatic control engineering that deals with monitoring a system, identifying when a fault has occurred, and determining the type of fault and its location. Fault detection is performed by analyzing the difference between sensor and actuator measurements and their expected values, derived from any model and called redundant values. It is common to say that an error is detected if the deviation or residue exceeds a certain predefined threshold. Fault isolation, in turn, must make it possible to locate the fault in the machine. The most recent method of fault detection and isolation, based on the flatness property, calculates redundant variables from the measurement of the flat output of the system and its successive time derivatives. Then, the residues are deduced from the difference between the measured variables and the redundant variables. Fault detection by this method is guaranteed. However, the use of a single flat output does not allow, in some cases, to isolate some faults. The idea proposed by the developers of the method was to use several flat outputs to increase the number of the residual signals, which would increase the chances of isolating more faults. However, it was also noticed that the choice of these flat outputs is not arbitrary. That is, there are flat outputs that, when used together, increase the isolability of faults and others that do not. One of the objectives of this manuscript is to characterize the flat outputs in order to obtain a better fault isolability. This characterization is then verified by simulations and experiments on a hydraulic system, the three-tank system.Over the last decade, numerous studies have shown that there are systems such as thermal systems, viscoelastic systems and chemical systems that can be modeled by fractional differential equations. Therefore, classical methods of fault detection and isolation, originally developed to deal with integer order systems, were not suitable for fractional order systems, and fault detection and isolation methods specific to fractional order systems had to be developed. A second objective of this manuscript is to extend the characterization of flat outputs, proposed for the class of integer order flat systems to the class of fractional order linear flat systems, and then to apply this characterization to the detection and isolation of faults that may appear on the sensors and actuators of these systems. The effectiveness of this characterization is also verified by simulations on a bi-dimensional thermal system
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Nicolau, Florentina. "Géométrie et platitude des systèmes de contrôle de poids différentiel minimal." Thesis, Rouen, INSA, 2014. http://www.theses.fr/2014ISAM0014/document.
Full textAbstract:
Premièrement, nous avons caractérisé les systèmes multi-entrées, affines par rapport aux contrôles, linéarisables dynamiquement via une pré-intégration d'un contrôle bien choisi. Ils forment une classe particulière de systèmes plats : ils ont un poids différentiel de n+m+1, où m est le nombre de contrôles et n est la dimension de l'état. Nous avons présenté des formes normales compatibles avec les sorties plates minimales et décrit toutes les sorties plates minimales. Nous avons appliqué nos résultats à plusieurs exemples. Deuxièmement, nous avons décrit les systèmes multi-entrées statiquement équivalents à une forme triangulaire compatible avec la forme multi-chaînée. Ensuite, la platitude de ces systèmes a été analysée et résolue. Nous avons discuté les singularités dans l'espace de contrôle et déterminé toutes les sorties plates. Nous avons appliqué ces résultats au système mécanique d'une pièce roulant sans glissement sur une table en mouvementFirstly, we study flatness of multi-input control-affine systems. We give a complete geometric characterization of systems that become static feedback linearizable after a one-fold prolongation of a suitably chosen control. They form a particular class of flat systems, that is of differential weight equal to n+m+l, where n is the dimension of the state-space and m is the number of controls. We illustrate our results by several examples. Secondly, we give a complete geometric characterization of systems locally static feedback equivalent to a triangular form compatible with the m-chained form. We analyze and solve their flatness. We discuss singularities and provide a system of first order PDE's to be solved in order to find all x-flat outputs. We illustrate our results by an application to a mechanical system: the coin rolling without slipping on a moving table
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Paraschivoiu, Marius 1968. "A posteriori finite element bounds for linear-functional outputs of coercive partial differential equations and of the Stokes problem." Thesis, Massachusetts Institute of Technology, 1997. http://hdl.handle.net/1721.1/50360.
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Vestin, Albin, and Gustav Strandberg. "Evaluation of Target Tracking Using Multiple Sensors and Non-Causal Algorithms." Thesis, Linköpings universitet, Reglerteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-160020.
Full textAbstract:
Today, the main research field for the automotive industry is to find solutions for active safety. In order to perceive the surrounding environment, tracking nearby traffic objects plays an important role. Validation of the tracking performance is often done in staged traffic scenarios, where additional sensors, mounted on the vehicles, are used to obtain their true positions and velocities. The difficulty of evaluating the tracking performance complicates its development. An alternative approach studied in this thesis, is to record sequences and use non-causal algorithms, such as smoothing, instead of filtering to estimate the true target states. With this method, validation data for online, causal, target tracking algorithms can be obtained for all traffic scenarios without the need of extra sensors. We investigate how non-causal algorithms affects the target tracking performance using multiple sensors and dynamic models of different complexity. This is done to evaluate real-time methods against estimates obtained from non-causal filtering. Two different measurement units, a monocular camera and a LIDAR sensor, and two dynamic models are evaluated and compared using both causal and non-causal methods. The system is tested in two single object scenarios where ground truth is available and in three multi object scenarios without ground truth. Results from the two single object scenarios shows that tracking using only a monocular camera performs poorly since it is unable to measure the distance to objects. Here, a complementary LIDAR sensor improves the tracking performance significantly. The dynamic models are shown to have a small impact on the tracking performance, while the non-causal application gives a distinct improvement when tracking objects at large distances. Since the sequence can be reversed, the non-causal estimates are propagated from more certain states when the target is closer to the ego vehicle. For multiple object tracking, we find that correct associations between measurements and tracks are crucial for improving the tracking performance with non-causal algorithms.
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Wang, Huei-Chi, and 王惠琪. "Design of Current Mode Operational Amplifier with Differential Input and Differential Output." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/90020224361357870789.
Full textAbstract:
碩士淡江大學
電機工程學系
85
In the last few decades, the analogue designers more thought about processing signal by current mode signal. As the current mode circuit compares with the voltage mode circuit, the former proves to be two conceptual advantages: higher frequency capabilities and larger dynamic range. And the architecture of current mode circuit form, it is more convenient and direct to copy or operate the signal than the voltage mode. Such as the switch current filter in the recently developing. In this thesis, a new CMOS current operational amplifier (COA) with fully differential input and differential output is proposed and analyzed. The amplifier is implemented from a differential current mirror input transimpedance stage followed by a differential output transconductance gain stage. A differential mode design technique is proposed and used in the feedback circuit. The simulation results of the new COA are based upon the 0.5um CMOS process and ±1.5V supply voltage. The new COA exhibits an open-loop differential gain of 51.71dB with the gain-bandwidth product 314MHz and a settling time of 14ns. To design VLSI circuit in the recent, the mix mode circuit design is the future trend in order to cooperate with the digital process. So the low voltage, and low power analogue circuit design is indispensable. Specially in the mobile personal communication system. So in this paper, we first analysis the basis current cell circuits, e.g. low voltage current mirror. And we will discuss the property of the circuit, as follows describe: (a) bandwidth improvement (b) parasitic capacitor effect improvement (c) unit step function time response (d) temperature stability discussion (e) bias circuit and dynamic range discussion In the last, the applications of the COA in processing current signals are proven to be the counterpart of the traditional voltage mode operational amplifier (VOA). The current integrator and the current Biquad filter show their duality with voltage integrator and Biquad. In the domain of filter design, COA is proven to be applicable to MOS-C current filter as well as SC voltage filter. Thus this COA can be used to process the signals on chip.
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WU, YUAN-HUI, and 吳源輝. "Design of Mixed-mode Differential Output Reference Voltages." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2k9tva.
Full textAbstract:
碩士國立虎尾科技大學
電子工程系碩士班
107
In this thesis, two Mixed-Mode Differential Output Reference Voltage Circuits have been proposed. The output of the first proposed circuit is with traditional differential output structure and a series-connected MOSFET is used at the output of the second proposed circuit as the level-shifter. Comparing with the existed reference voltage circuits, which were usually combined with the positive/negative temperature-coefficient characteristics with selected weighting ratios to generate a zero temperature-coefficient reference voltages, the proposed circuits utilize only the negative temperature-coefficient characteristic from BJT junction voltage and the threshold voltage of MOSFET to eliminate each other so we can achieve a zero temperature-coefficient reference voltage circuits. Compared with the known circuits, the circuits proposed in this thesis are with simpler circuit structure, less chip area, and there is no operational amplifier needed in the proposed designs. Detailed working principles have been explored in this thesis. Both the proposed circuits have been simulated by HSPICE simulation program with TSMC 0.35um and TSMC 0.18um process parameters, also the proposed circuits have been tape-out. The pre and post layout simulation results are consistent with the theoretical analysis which can be used to prove the feasibility of the proposed circuits. The proposed Mixed-Mode Differential Output Voltage circuit can be applied to different analog integrated circuit applications
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Chen, Hsin-Ann, and 陳信安. "1.8V Differential Voltage Output Digital-to-Analog Converter." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/45664356115532259156.
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TSENG, BO-WEI, and 曾柏崴. "CMOS Differential Output Reference Voltage Design for Practical Applications." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/qemgc8.
Full textAbstract:
碩士國立虎尾科技大學
電子工程系碩士班
106
In this thesis, three different kinds of CMOS differential output reference voltage circuits have been proposed. The design principle is properly combine the positive temperature-coefficient and negative temperature-coefficient parameters to achieve a zero temperature-coefficient voltage. Both the positive and negative temperature-coefficients are obtained from the characteristics of the BJT and MOSFET biased in weak-inversion region. As compared with the present existed circuits, all the proposed reference voltage circuits do not use any operational amplifier in the design, and also do not need to perform the second order nonlinear compensation to the negative temperature-coefficient generation circuits, therefore they benefit from simpler circuit structure, smaller chip area and lower power consumption. In addition to the detailed design principle disclosed in this thesis, the proposed circuits have been simulated by HSPICE simulation program with a 0.18μm process parameters. Besides, after the layout of the proposed reference voltage circuits has been finished, all the proposed circuits have been taped-out. The simulation results show that, when the power supply voltage is 1.5V and 2.2V, respectively, the temperature ranges from -20°C to 120°C, the average output voltage of the first proposed circuit is about 734mV, the maximum output voltage variation is 14.39mV, the power dissipation is 0.288mW, the temperature coefficient is about 140ppm/°C. The average output voltage of the second proposed circuit the is about 730mV, the maximum output voltage variation is 30.673mV, the power dissipation is 0.122mW, and the temperature coefficient is about 300ppm/°C. Finally, the average output voltage of the last proposed circuit is about 763mV, the maximum output voltage variation is 29.143mV, the power dissipation is 0.117mW, and the temperature coefficient is about 272.64ppm/°C. The simulation results are consistent with theoretical analysis, it also confirm the validity of the design principles. The proposed CMOS differential output reference voltage circuits are expected to be used in the design of analog integrated circuits and other practical applications.
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Prud'homme, C., D. V. Rovas, K. Veroy, L. Machiels, Y. Maday, Anthony T. Patera, and G. Turinici. "Reduced-Basis Output Bound Methods for Parametrized Partial Differential Equations." 2002. http://hdl.handle.net/1721.1/4008.
Full textAbstract:
We present a technique for the rapid and reliable prediction of linear-functional outputs of elliptic (and parabolic) partial differential equations with affine parameter dependence. The essential components are (i) (provably) rapidly convergent global reduced-basis approximations -- Galerkin projection onto a space WN spanned by solutions of the governing partial differential equation at N selected points in parameter space; (ii) a posteriori error estimation -- relaxations of the error-residual equation that provide inexpensive yet sharp and rigorous bounds for the error in the outputs of interest; and (iii) off-line/on-line computational procedures -- methods which decouple the generation and projection stages of the approximation process. The operation count for the on-line stage -- in which, given a new parameter value, we calculate the output of interest and associated error bound -- depends only on N (typically very small) and the parametric complexity of the problem; the method is thus ideally suited for the repeated and rapid evaluations required in the context of parameter estimation, design, optimization, and real-time control.Singapore-MIT Alliance (SMA)
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CAI, ZONG-XIAN, and 蔡宗憲. "Design of Improved Low-Powered BiCMOS Differential Output Reference Voltages." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/2u3mj5.
Full textAbstract:
碩士國立虎尾科技大學
電子工程系碩士班
107
This thesis presents three kinds of improved low-power BiCMOS differential output reference voltage circuit design The basic design principle of the reference voltage circuit is to generate the positive temperature coefficient voltage module and the negative temperature coefficient voltage module, respectively, and then the positive and negative temperature coefficient parametens generated by the positive temperature coefficient voltage module and the negative temperature coefficient voltage module are combined by the appropriate weight ratio. The positive and negative temperature coefficient effects cancel each other to obtain a zero temperature coefficient reference voltage which does not vary with temperature. In addition to providing detailed design principles, this thesis uses HSPICE circuit simulation progran to perform pre- and post-layout simulations and uses TSMC 0.18 um process parameters for layout design and tape-out. The supply voltages for the proposed circuits are 1.8V, 2.0V and 2.4V, respectively. Also,the temperature range is increased from -20 ° C to 120 ° C. The improved low-power BiCMOS differential output reference voltage circuit proposed in this thesis can be applied to various related analog circuit design as a circuit module.
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Hung, Kai Lun, and 洪楷倫. "High Output Power S-band Differential VCO Design Using GaN HEMT Technology." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/49030760521194799900.
Full textAbstract:
碩士長庚大學
電子工程學系
101
This thesis contains two parts: The first part is the usage of 0.5-μm GaN HEMT process for the design work on the S-band 3.5 GHz differential VCO. Second part is using 0.5-μm process transistors with printed circuit board (FR4 PCB) to design of a single-ended series of negative impedance 2.4 GHz VCO. In the differential VCO section, we designed a 3.532 GHz VCO by cross-coupled structure. This 3.532 GHz VCO could be achieved the output power of 12.01 dBm, tuning range of 0.45 GHz, and the phase noise at 1 MHz offset can be obtained -121.19 dBc/Hz. In the single-ended VCO section, we designed a 2.445 GHz VCO by common gate structure. This 2.445 GHz VCO could be achieved the output power 20.01 dBm, tuning range of 19 MHz, and the phase noise at 1 MHz offset can be obtained -140.33 dBc/Hz.
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Wu, Wei-Min, and 吳維旻. "A Balun-Less Frequency Multiplier with Differential Output by Current Flow Manipulation." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/71258848151704509690.
Full textAbstract:
碩士國立中央大學
電機工程學系
104
This thesis presents a balun-less frequency multiplier architecture which can provide differential output without any additional balun required. The architecture manipulates the current flows around the multiplier core to enforce the output currents being generated from the same current loop by introducing a multifunction network at the multiplier input. This network works as an impedance matching network at the input frequency fin while becoming a band-stop filter at the desired output harmonic frequency Nfin for rejecting any N-th harmonic current flowing back to the multiplier input. Moreover, the intrinsic Miller capacitance of the multiplier transistors, Cgd, provides high band-stop rejection which greatly eases the multifunction network design. Hence the multiplier outputs are guaranteed to be perfectly differential as the output currents with same amplitude and phase flow into and out the loads with same impedance, respectively. A 60-GHz frequency doubler (FD) realized in a 90-nm CMOS technology is designed to verify the proposed frequency multiplier architecture. The measured phase and amplitude imbalance of the FD are only 0.5° and 0.2 dB while providing conversion gain of -5.5 dB at the output frequency of 60 GHz. The 3-dB fractional bandwidth is 22.6%. The fundamental rejection is better than 16.3 dB within the bandwidth. The FD consumes 15.9 mW from a 1 V supply as an input signal with -2 dBm power is applied. A 94-GHz receiver front-end (RFE) which integrates a five-stage low-noise amplifier, a broadband LO balun, a single-balanced mixer, and a FD adopting the proposed FD architecture is also exhibited in this thesis. Implemented in a 90-nm CMOS technology, the RFE can provide simulated voltage conversion gain of 26.3 dB and double-sideband noise figure of 12.2dB at the IF frequency of 10 MHz while only consuming 20.4 mW from a 1 V supply.
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Wu, Po-Chi, and 吳柏奇. "A CMOS-MEMS Capacitive Accelerometer with Differential LC-tank Oscillator and Digital Output." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/776vk5.
Full textAbstract:
碩士國立交通大學
電控工程研究所
101
The rapid development of electronics products makes the entire semiconductor technology continue to progress. More and more mobile devices need various sensors, leading to the growing demand for MEMS sensors. The MEMS sensors whose fabrication process is compatible to the standard CMOS process are called CMOS MEMS sensors. The CMOS MEMS sensors have the advantages of low cost and high performance. This thesis used TSMC 0.18μm standard CMOS process and post process supported by National Chip Implementation Center to complete a CMOS MEMS accelerometer. This accelerometer has capacitive sensing mechanism, and integrates the sensing capacitor with an oscillator circuit and the back-end circuit to have a frequency and digital output. The oscillation frequency can be influenced by the sensing capacitor. By detecting the variation of the oscillator output frequency, this accelerometer can define the acceleration value applied on this chip. The combination of capacitive sensing and frequency output has the advantage of capacitor values being less sensitive to temperature, post process being relatively simple, no need of complex analog-digital converters and higher sensitivity and linearity. The measurement result shows that this accelerometer can achieve 3.44 MHz/g sensitivity and 0.4mg/rtHz resolution.
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Yang, Chung Han, and 楊忠翰. "Output Current Control and Steady-state Error Compensation of Differential Grid-tied Boost Inverters." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/6u2wk5.
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Chuan-YuSun and 孫全佑. "A Fifth-Order Butterworth OTA-C Lowpass Filter with Multiple-Output Differential-Input OTA for ECG Acquisition." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/78554n.
Full textAbstract:
碩士國立成功大學
電機工程學系
105
This study proposes a fifth-order Butterworth operational transconductance amplifier-C (OTA-C) low-pass filter (LPF) with multiple-output differential-input (MODI) OTA structure and metal–insulator–metal capacitors for electrocardiography applications. The current division technology is used as an alternative output pair to provide multiple outputs and achieve high linearity. This technique reduces the number of OTAs of the fifth-order LPF from 11 to 6 as compared with the conventional structure. The design issue of linearity and noise are also considered in the implementation of LPF. In order to achieve a filter with large-time constant and low noise, linearized MODI OTA structures with reduced transconductance and impedance scaler circuits for capacitors are used. OTA-based circuits is operated in the subthreshold region and supply voltage of 1V to conserve power consumption due to the battery life of the portable device and the critical area of the digital processor required in the circuit. The proposed filter is fabricated in a 0.18 µm complementary metal–oxide–semiconductor technology with a core area of 0.135 mm2. The experimental results show that the dynamic range (DR) is 58.44 dB, achieved a total harmonic distortion (THD) of -59 dB under a bandwidth of 250 Hz and input voltage of 100 mV at a 1 V supply voltage. The total power dissipation is 390 nW.
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Chia, Wee Lee Mechanical & Manufacturing Engineering Faculty of Engineering UNSW. "Multiple-Input Multiple-Output (MIMO) blind system identification for operational modal analysis using the Mean Differential Cepstrum (MDC)." 2007. http://handle.unsw.edu.au/1959.4/40738.
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The convenience of Operational Modal Analysis (OMA), over conventional Experimental Modal Analysis (EMA), has seen to its increasing popularity over the last decade for the purpose of evaluating dynamic properties of structures. OMA features an advantage of requiring only output information, which is in tandem with its main drawback of lacking scaled modeshape information. While correctly scaled modeshapes can be assumed under a restrictive assumption of spectrally white inputs, in reality, input spectra are at best broadband in nature. In this thesis, an OMA method for Multiple-Input Multiple-Output (MIMO) applications in mechanical structures is developed. The aim is to separate MIMO responses into a collection of Single-Input Single-Output (SISO) processes (matrix FRF) using cepstral-based methods, under less restrictive and hence more realistic coloured broadband excitation. Existing cepstral curve-fitting techniques can be subsequently applied to give regenerated FRFs with correct relative scaling. This cepstral-based method is based on the matrix Mean Differential Cepstrum (MDC) and operates in the frequency domain. Application of the matrix MDC onto MIMO responses leads to a matrix differential equation which together with the use of finite differences, directly solves or identifies the matrix FRF in a propagative manner. An alternative approach based on whitened MIMO responses can be similarly formulated for the indirect solution of the matrix FRF. Both the direct and indirect approaches can be modified with a Taylor series approximation to give a total of four propagative solution sequences. The method is developed using relatively simple simulated and experimental systems, involving both impulsive and burst random excitations. Detailed analysis of the results is performed using more complicated Single-Input Multiple-Output (SIMO) and MIMO systems, involving both driving and non-driving point measurements. The use of the matrix MDC method together with existing cepstral curve-fitting technique to give correct relative scaling is demonstrated on a simulated MIMO system with coloured inputs. Accurate representation of the actual FRFs is achieved by the matrix MDC technique for SIMO set-ups. In MIMO scenarios, excellent identification was obtained for the case of simulated impulsive input while the experimental and burst random input cases were less favourable. The results show that the matrix MDC technique works in MIMO scenarios, but possible noise-related issues need to be addressed in both experimental and burst random input cases for a more satisfactory identification outcome.
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Veroy, K., T. Leurent, C. Prud'homme, D. V. Rovas, and Anthony T. Patera. "Reliable Real-Time Solution of Parametrized Elliptic Partial Differential Equations: Application to Elasticity." 2002. http://hdl.handle.net/1721.1/4009.
Full textAbstract:
The optimization, control, and characterization of engineering components or systems require fast, repeated, and accurate evaluation of a partial-differential-equation-induced input-output relationship. We present a technique for the rapid and reliable prediction of linear-functional outputs of elliptic partial differential equations with affine parameter dependence. The method has three components: (i) rapidly convergent reduced{basis approximations; (ii) a posteriori error estimation; and (iii) off-line/on-line computational procedures. These components -- integrated within a special network architecture -- render partial differential equation solutions truly "useful": essentially real{time as regards operation count; "blackbox" as regards reliability; and directly relevant as regards the (limited) input-output data required.Singapore-MIT Alliance (SMA)
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Wu, Min-Kang, and 吳旻剛. "A Study of Channel Capacity of Optimal Multiple-Input Multiple-Output System Antenna Element Spacing by Applying Dynamic Differential Evolution." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/81456597174321881780.
Full textAbstract:
碩士淡江大學
電機工程學系碩士班
98
The geometrical shape of antenna arrays for maximizing the average channel capacity of the system in a multiple-input multiple-output (MIMO) link is investigated. The optimum element spacing of the transmitting antenna is also included. In this paper, channel capacity of multiple-input multiple-output narrowband system in indoor wireless channels at 5-GHz U-NII (Unlicensed-National Information Infrastructure) bands is calculated. An optimization procedure for the element spacing of the antenna transmitter in narrowband wireless communication system is presented. The frequency responses of different transceiver antenna element spacing are computed by shooting and bouncing ray/image (SBR/Image) techniques, and the channel frequency response is further used to calculate corresponding channel capacity. The transmitter is in the center of the indoor environment and the receivers are uniform intervals distribution, which 150 measurements with 0.25m intervals in the whole wooden table in indoor environment. And the inter-element separation of Receiver antennas (Rx) is 0.03m. Linear shaped array, L shaped array, T shaped array and rectangular shaped array geometries with non-uniform inter-element spacing are investigated for both line-of-sight (LOS) and non-LOS (NLOS) scenarios. The optimal element spacing of antenna for maximizing the channel capacity is searched by dynamic differential evolution (DDE). Numerical results have shown that our proposed method is effective for increasing average channel capacity. It is also found that L shaped array has the highest channel capacity and the improvement ratio for rectangular shaped array is largest.
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LIU, CHAN-CHUAN, and 劉展銓. "Design of Robust-Optimal Static Output Feedback Controllers with Low Trajectory Sensitivity for Uncertain TS Fuzzy Systems Using Improved Differential Evolution Algorithm." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/kggvwm.
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碩士國立高雄應用科技大學
機械工程系
105
In this paper, an integrative method, which combines the robust stabilizability condition, the orthogonal-functions approach (OFA), and the Taguchi-sliding-based differential evolution algorithm (TSBDEA), is presented to design the robust-stable and quadratic-finite-horizon-optimal static output feedback parallel-distributed- compensation (PDC) controller with low trajectory sensitivity such that (i) the Takagi-Sugeno (TS) fuzzy control system with elemental parametric uncertainties can be robustly stabilized, and (ii) a quadratic finite-time integral performance index including a quadratic sensitivity term for nominal TS fuzzy control system can be minimized. The robust stabilizability condition is proposed in terms of linear matrix inequalities (LMIs). By using the OFA and the robust stabilizability condition, the robust-stable and quadratic-finite-horizon-optimal static output feedback PDC control problem for the TS fuzzy dynamic systems is transformed into a static constrained-optimization problem represented by the algebraic equations with constraint of LMI-based robust stabilizability condition; thus greatly simplifying the optimal static output feedback PDC controller design problem. Then, for the static constrained-optimization problem, the TSBDEA is applied to find the robust-stable and quadratic-finite-horizon-optimal static output feedback PDC controllers with low trajectory sensitivity of the TS fuzzy control systems with elemental parametric uncertainties. A design example of robust-stable and quadratic-finite-horizon-optimal static output feedback PDC controllers with low trajectory sensitivity for uncertain nonlinear Chua circuit is given to demonstrate the applicability of the proposed integrative approach.
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Rajan, G. Susinder. "Low Decoding Complexity Space-Time Block Codes For Point To Point MIMO Systems And Relay Networks." Thesis, 2008. http://hdl.handle.net/2005/742.
Full textAbstract:
It is well known that communication using multiple antennas provides high data rate and reliability. Coding across space and time is necessary to fully exploit the gains offered by multiple input multiple output (MIMO) systems. One such popular method of coding for MIMO systems is space-time block coding. In applications where the terminals do not have enough physical space to mount multiple antennas, relaying or cooperation between multiple single antenna terminals can help achieve spatial diversity in such scenarios as well. Relaying techniques can also help improve the range and reliability of communication. Recently it has been shown that certain space-time block codes (STBCs) can be employed in a distributed fashion in single antenna relay networks to extract the same benefits as in point to point MIMO systems. Such STBCs are called distributed STBCs. However an important practical issue with STBCs and DSTBCs is its associated high maximum likelihood (ML) decoding complexity. The central theme of this thesis is to systematically construct STBCs and DSTBCs applicable for various scenarios such that are amenable for low decoding complexity.
The first part of this thesis provides constructions of high rate STBCs from crossed product algebras that are minimum mean squared error (MMSE) optimal, i.e., achieves the least symbol error rate under MMSE reception. Moreover several previous constructions of MMSE optimal STBCs are found to be special cases of the constructions in this thesis.
It is well known that STBCs from orthogonal designs offer single symbol ML decoding along with full diversity but the rate of orthogonal designs fall exponentially with the number of transmit antennas. Thus it is evident that there exists a tradeoff between rate and ML decoding complexity of full diversity STBCs. In the second part of the thesis, a definition of rate of a STBC is proposed and the problem of optimal tradeoff between rate and ML decoding complexity is posed. An algebraic framework based on extended Clifford algebras is introduced to study the optimal tradeoff for a class of multi-symbol ML decodable STBCs called ‘Clifford unitary weight (CUW) STBCs’ which include orthogonal designs as a special case. Code constructions optimally meeting this tradeoff are also obtained using extended Clifford algebras. All CUW-STBCs achieve full diversity as well.
The third part of this thesis focusses on constructing DSTBCs with low ML decoding complexity for two hop, amplify and forward based relay networks under various scenarios. The symbol synchronous, coherent case is first considered and conditions for a DSTBC to be multi-group ML decodable are first obtained. Then three new classes of four-group ML decodable full diversity DSTBCs are systematically constructed for arbitrary number of relays. Next the symbol synchronous non-coherent case is considered and full diversity, four group decodable distributed differential STBCs (DDSTBCs) are constructed for power of two number of relays. These DDSTBCs have the best error performance compared to all previous works along with low ML decoding complexity. For the symbol asynchronous, coherent case, a transmission scheme based on orthogonal frequency division multiplexing (OFDM) is proposed to mitigate the effects of timing errors at the relay nodes and sufficient conditions for a DSTBC to be applicable in this new transmission scheme are given. Many of the existing DSTBCs including the ones in this thesis are found to satisfy these sufficient conditions. As a further extension, differential encoding is combined with the proposed transmission scheme to arrive at a new transmission scheme that can achieve full diversity in symbol asynchronous, non-coherent relay networks with no knowledge of the timing errors at the relay nodes. The DDSTBCs in this thesis are proposed for application in the proposed transmission scheme for symbol asynchronous, non-coherent relay networks. As a parallel to the non-coherent schemes based on differential encoding, we also propose non-coherent schemes for symbol synchronous and symbol asynchronous relay networks that are based on training. This training based transmission scheme leverages existing coherent DSTBCs for non-coherent communication in relay networks. Simulations show that this training scheme when used along with the coherent DSTBCs in this thesis outperform the best known DDSTBCs in the literature.
Finally, in the last part of the thesis, connections between multi-group ML decodable unitary weight (UW) STBCs and groups with real elements are established for the first time. Using this connection, we translate the necessary and sufficient conditions for multi-group ML decoding of UW-STBCs entirely in group theoretic terms. We discuss various examples of multi-group decodable UW-STBCs together with their associated groups and list the real elements involved. These examples include orthogonal designs, quasi-orthogonal designs among many others.