Tesis sobre el tema "Numerical Synthesis"
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Graham, R. K. "Numerical synthesis of dual-reflector antenna systems". Thesis, University of Southampton, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373929.
Texto completoBärlund, Johnny. "Numerical Investigation on Spherical Harmonic Synthesis and Analysis". Thesis, KTH, Geodesi och satellitpositionering, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-171779.
Texto completoProcacci, Alberto. "Numerical simulation of nanoparticle synthesis in a turbulent jet". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2017.
Buscar texto completoGao, Xitong. "Structural optimization of numerical programs for high-level synthesis". Thesis, Imperial College London, 2016. http://hdl.handle.net/10044/1/42498.
Texto completoMeister, Neil E. "Application of numerical optimization techniques to surface combatant design synthesis". Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1998. http://handle.dtic.mil/100.2/ADA355524.
Texto completo"September 1998." Thesis advisor(s): Matthew D. Kelleher, C.N. Calvano. Includes bibliographical references (p. 229-230). Also available online.
Lou, Zhenjun. "Kinematic representations and numerical methods in precision position synthesis of mechanisms". Thesis, King's College London (University of London), 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429316.
Texto completoSargolzaei, Parviz. "Numerical synthesis of a single offset reflector with dielectric cone feed". Thesis, University of Southampton, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.242409.
Texto completoPšeno, Daniel. "Buzené chaotické oscilátory". Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219111.
Texto completoIvie, Jimmy John. "A numerical model of the synthesis of carbon black by benzene pyrolysis". Thesis, Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/10954.
Texto completoOrr, Sarah Isobel. "Numerical simulation of coupled strings with application to physics-based sound synthesis". Thesis, Queen's University Belfast, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.602783.
Texto completoFreixes, Guerreiro Marc. "Adding expressiveness to unit selection speech synthesis and to numerical voice production". Doctoral thesis, Universitat Ramon Llull, 2021. http://hdl.handle.net/10803/672066.
Texto completoEl habla es una de las formas de comunicación más naturales y directas entre seres humanos, ya que codifica un mensaje y también claves paralingüísticas sobre el estado emocional del locutor, el tono o su intención, convirtiéndose así en fundamental en la consecución de una interacción humano-máquina (HCI) más natural. En este contexto, la generación de habla expresiva para el canal de salida de HCI es un elemento clave en el desarrollo de tecnologías asistenciales o asistentes personales entre otras aplicaciones. El habla sintética puede ser generada a partir de habla gravada utilizando métodos basados en corpus como la selección de unidades (US), que pueden conseguir resultados de alta calidad, pero de expresividad restringida a la propia del corpus. A fin de mejorar la calidad de la salida de la síntesis, la tendencia actual es construir bases de datos de voz cada vez más grandes, siguiendo especialmente la aproximación de síntesis llamada End-to-End basada en técnicas de aprendizaje profundo. Sin embargo, gravar corpus ad-hoc para cada estilo expresivo deseado puede ser extremadamente costoso o incluso inviable si el locutor no es capaz de realizar adecuadamente los estilos requeridos para una aplicación dada (ej: canto en el dominio de la narración de cuentos). Alternativamente, nuevos métodos basados en la física de la producción de voz se han desarrollado en la última década gracias al incremento en la potencia computacional. Por ejemplo, vocales o diptongos pueden ser obtenidos utilizando el método de elementos finitos (FEM) para simular la propagación de ondas acústicas a través de una geometría 3D realista del tracto vocal obtenida a partir de resonancias magnéticas (MRI). Sin embargo, dado que los principales esfuerzos en estos métodos de producción numérica de voz se han focalizado en la mejora del modelado del proceso de generación de voz, hasta ahora se ha prestado poca atención a su expresividad. Además, la colección de datos para estas simulaciones es muy costosa, además de requerir un largo postproceso manual como el necesario para extraer geometrías 3D del tracto vocal a partir de MRI. El objetivo de la tesis es añadir expresividad en un sistema que genera voz neutra, sin tener que adquirir datos expresivos del locutor original. Per un lado, se añaden capacidades expresivas a un sistema de conversión de texto a habla basado en selección de unidades (US-TTS) dotado de un corpus de voz neutra, para abordar necesidades específicas y concretas en el ámbito de la narración de cuentos, como son la voz cantada o situaciones de suspense. Para ello, la voz se parametriza utilizando un modelo harmónico y se transforma al estilo expresivo deseado de acuerdo con un sistema experto. Se presenta una primera aproximación, centrada en la síntesis de suspense creciente para la narración de cuentos, y se demuestra su viabilidad en cuanto a naturalidad y calidad de narración de cuentos. También se añaden capacidades de canto al sistema US-TTS mediante la integración de módulos de transformación de habla a voz cantada en el pipeline del TTS, y la incorporación de un módulo de generación de prosodia expresiva que permite al módulo de US seleccionar unidades más cercanas a la prosodia cantada obtenida a partir de la partitura de entrada. Esto resulta en un framework de síntesis de conversión de texto a habla y voz cantada basado en selección de unidades (US-TTS&S) que puede generar voz hablada y cantada a partir del mismo pequeño corpus de voz neutra (~2.6h). De acuerdo con los resultados objetivos, la estrategia de US guiada por la partitura permite reducir los factores de modificación de pitch requeridos para producir voz cantada a partir de las unidades de voz hablada seleccionadas, pero en cambio tiene una efectividad limitada con los factores de modificación de duraciones debido a la corta duración de las vocales habladas neutras. Los resultados de las pruebas perceptivas muestran que, a pesar de obtener una naturalidad obviamente inferior a la ofrecida por un sintetizador profesional de voz cantada, el framework puede abordar necesidades puntuales de voz cantada para la síntesis de narración de cuentos con una calidad razonable. La incorporación de expresividad se investiga también en la simulación numérica 3D de vocales basada en FEM mediante modificaciones en las señales de excitación glotal utilizando una aproximación fuente-filtro de producción de voz. Estas señales se generan utilizando un modelo Liljencrants-Fant (LF) controlado con el parámetro de forma del pulso Rd, que permite explorar el continuo de fonación laxo-tenso además del rango de frecuencias fundamentales, F0, de la voz hablada. Se analiza la contribución de la fuente glotal a los modos de alto orden en la síntesis FEM de las vocales cardinales [a], [i] y [u] mediante la comparación de los valores de energía de alta frecuencia (HFE) obtenidos con geometrías realistas y simplificadas del tracto vocal. Las simulaciones indican que los modos de alto orden se prevén perceptivamente relevantes de acuerdo con valores de referencia de la literatura, particularmente para fonaciones tensas y/o F0s altas. En cambio, para vocales con una fonación laxa y/o F0s bajas los niveles de HFE pueden resultar inaudibles, especialmente si no hay ruido de aspiración en la fuente glotal. Después de este estudio preliminar, se han analizado las características de excitación de vocales alegres y agresivas de un corpus paralelo de voz en castellano con el objetivo de incorporar estos estilos expresivos de voz tensa en la simulación numérica de voz. Para ello, se ha usado el vocoder GlottDNN para analizar variaciones de F0 y pendiente espectral relacionadas con la excitación glotal en vocales [a]. Estas variaciones se mapean mediante la comparación con vocales sintéticas en valores de F0 y Rd para simular vocales que se asemejen a los estilos alegre y agresivo. Los resultados muestran que es necesario incrementar la F0 y disminuir la Rd respecto la voz neutra, con variaciones mayores para alegre que para agresivo, especialmente para vocales acentuadas. Los resultados conseguidos en las investigaciones realizadas validan la posibilidad de añadir expresividad a la síntesis basada en corpus US-TTS y a la simulación numérica de voz basada en FEM. Sin embargo, hay margen de mejora. Por ejemplo, la estrategia aplicada a la producción numérica de voz se podría mejorar estudiando y desarrollando métodos de filtrado inverso, así como incorporando modificaciones del tracto vocal, mientras que el framework US-TTS&S desarrollado se podría beneficiar de los avances en técnicas de transformación de voz incluyendo transformaciones de la calidad de la voz, aprovechando la experiencia adquirida en la simulación numérica de vocales expresivas.
Speech is one of the most natural and direct forms of communication between human beings, as it codifies both a message and paralinguistic cues about the emotional state of the speaker, its mood, or its intention, thus becoming instrumental in pursuing a more natural Human Computer Interaction (HCI). In this context, the generation of expressive speech for the HCI output channel is a key element in the development of assistive technologies or personal assistants among other applications. Synthetic speech can be generated from recorded speech using corpus-based methods such as Unit-Selection (US), which can achieve high quality results but whose expressiveness is restricted to that available in the speech corpus. In order to improve the quality of the synthesis output, the current trend is to build ever larger speech databases, especially following the so-called End-to-End synthesis approach based on deep learning techniques. However, recording ad-hoc corpora for each and every desired expressive style can be extremely costly, or even unfeasible if the speaker is unable to properly perform the styles required for a given application (e.g., singing in the storytelling domain). Alternatively, new methods based on the physics of voice production have been developed in the last decade thanks to the increase in computing power. For instance, vowels or diphthongs can be obtained using the Finite Element Method (FEM) to simulate the propagation of acoustic waves through a 3D realistic vocal tract geometry obtained from Magnetic Resonance Imaging (MRI). However, since the main efforts in these numerical voice production methods have been focused on improving the modelling of the voice generation process, little attention has been paid to its expressiveness up to now. Furthermore, the collection of data for such simulations is very costly, besides requiring manual time-consuming postprocessing like that needed to extract 3D vocal tract geometries from MRI. The aim of the thesis is to add expressiveness into a system that generates neutral voice, without having to acquire expressive data from the original speaker. One the one hand, expressive capabilities are added to a Unit-Selection Text-to-Speech (US-TTS) system fed with a neutral speech corpus, to address specific and timely needs in the storytelling domain, such as for singing or in suspenseful situations. To this end, speech is parameterised using a harmonic-based model and subsequently transformed to the target expressive style according to an expert system. A first approach dealing with the synthesis of storytelling increasing suspense shows the viability of the proposal in terms of naturalness and storytelling quality. Singing capabilities are also added to the US-TTS system through the integration of Speech-to-Singing (STS) transformation modules into the TTS pipeline, and by incorporating an expressive prosody generation module that allows the US to select units closer to the target singing prosody obtained from the input score. This results in a Unit Selection based Text-to-Speech-and-Singing (US-TTS&S) synthesis framework that can generate both speech and singing from the same neutral speech small corpus (~2.6 h). According to the objective results, the score-driven US strategy can reduce the pitch scaling factors required to produce singing from the selected spoken units, but its effectiveness is limited regarding the time-scale requirements due to the short duration of the spoken vowels. Results from the perceptual tests show that although the obtained naturalness is obviously far from that given by a professional singing synthesiser, the framework can address eventual singing needs for synthetic storytelling with a reasonable quality. The incorporation of expressiveness is also investigated in the 3D FEM-based numerical simulation of vowels through modifications of the glottal flow signals following a source-filter approach of voice production. These signals are generated using a Liljencrants-Fant (LF) model controlled with the glottal shape parameter Rd, which allows exploring the tense-lax continuum of phonation besides the spoken vocal range of fundamental frequency values, F0. The contribution of the glottal source to higher order modes in the FEM synthesis of cardinal vowels [a], [i] and [u] is analysed through the comparison of the High Frequency Energy (HFE) values obtained with realistic and simplified 3D geometries of the vocal tract. The simulations indicate that higher order modes are expected to be perceptually relevant according to reference values stated in the literature, particularly for tense phonations and/or high F0s. Conversely, vowels with a lax phonation and/or low F0s can result in inaudible HFE levels, especially if aspiration noise is not present in the glottal source. After this preliminary study, the excitation characteristics of happy and aggressive vowels from a Spanish parallel speech corpus are analysed with the aim of incorporating this tense voice expressive styles into the numerical production of voice. To that effect, the GlottDNN vocoder is used to analyse F0 and spectral tilt variations associated with the glottal excitation on vowels [a]. These variations are mapped through the comparison with synthetic vowels into F0 and Rd values to simulate vowels resembling happy and aggressive styles. Results show that it is necessary to increase F0 and decrease Rd with respect to neutral speech, with larger variations for happy than aggressive style, especially for the stressed [a] vowels. The results achieved in the conducted investigations validate the possibility of adding expressiveness to both corpus-based US-TTS synthesis and FEM-based numerical simulation of voice. Nevertheless, there is still room for improvement. For instance, the strategy applied to the numerical voice production could be improved by studying and developing inverse filtering approaches as well as incorporating modifications of the vocal tract, whereas the developed US-TTS&S framework could benefit from advances in voice transformation techniques including voice quality modifications, taking advantage of the experience gained in the numerical simulation of expressive vowels.
Torin, Alberto. "Percussion instrument modelling in 3D : sound synthesis through time domain numerical simulation". Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/31029.
Texto completoDi, Paola Vincenzo. "Classification of 3-dimensional persistent screw systems: a numerical approach". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020.
Buscar texto completoPanzitta, Michael James. "Synthesis of numerical integrators for the real-time digital simulation of continuous systems". Doctoral diss., University of Central Florida, 1994. http://digital.library.ucf.edu/cdm/ref/collection/RTD/id/3046.
Texto completoReal-time digital simulation is a powerful means for engineers and scientists in government, industry, and academia to perform research and training as well as serving as a basis for many commercial applications. Due to the special constraints imposed by digitally simulating continuous systems in real time, however, many of these systems either require costly high-speed components or are unable to provide suitable performance characteristics using affordable computers. This dissertation describes a new technique for the synthesis of numerical integrators specifically designed for the real-time digital simulation of continuous systems. This methodology is based upon the fact that the state derivatives in a simulation model typically have a significantly limited bandwidth. This information is exploited to improve the efficiency of numerical integrators by selecting the coefficients of a general-form integrator such that it approximates an ideal integrator over the limited frequency spectrum of the state derivative.
Ph.D.
Doctorate;
Department of Electrical and Computer Engineering
Engineering
Electrical and Computer Engineering
135 p.
xix, 135 leaves, bound : ill. ; 28 cm.
Coleman, Keenan L. "On the numerical solution of the integral equation formulation for transient structural synthesis". Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/43891.
Texto completoStructural synthesis is the analysis of the dynamic response of a system when either subsystems are combined (substructure coupling) or modifications are made to substructures (structural modification). The integral equation formulation for structural synthesis is a method that requires only the baseline transient response, the baseline modal parameters, and the impedance of the structural modification. The integral formulation results in a Volterra integral equation of the second-kind. An adaptive time-marching scheme is utilized to solve the integral equation formulation for structural synthesis. When structural modifications of large magnitude are made, the solution to the integral equation can become unstable. To overcome this conditional stability, the derivative of the synthesis equation is examined and demonstrated to be stable regardless of the magnitude of the structural modification.
Clarke, Samuel R. (Samuel Robert). "Development of a FEM waveguide code, incorporating Fast Frequency Techniques, for numerical synthesis". Thesis, Stellenbosch : Stellenbosch University, 2002. http://hdl.handle.net/10019.1/52762.
Texto completoENGLISH ABSTRACT: A computational tool for numerical synthesis via optimization is developed. Only two port waveguide devices are considered. The Finite Element Method (FEM) is used for the electromagnetic analysis. Specifically, the frequency domain electric field FEM is used with vector curl-conforming constant tangential/linear normal brick-shaped elements. Special boundary conditions are used at the ports. These boundary conditions only consider dominant mode propagation. The issues surrounding the implementation of this formulation are discussed. The results generated using this code compare favorably to examples from independent sources. A parametric mesher that is used in conjunction with the FEM is developed. This is done to eliminate the need for human intervention during each iteration of the synthesis procedure. Fast Frequency (FF) techniques are presented to reduce the computational requirements of the synthesis. FF techniques reduce the cost of calculating many frequency samples in a specified band and do not reduce the computational requirements of computing a FEM solution at a single frequency. The FF techniques presented are: Asymptotic Waveform Evaluation (AWE), Model Based Asymptotic Waveform Evaluation (MB-AWE) and Model Based Parameter Estimation (MBPE) . The results obtained using these techniques are compared and the most suitable technique for the synthesizer is selected. MBPE is selected as the most suitable technique for this application. An adaptive sampling algorithm for Model Based Parameter Estimation is presented. The algorithm relies on the difference between multiple models generated from the same samples to determine the sample locations. The use of this algorithm enables a model of a narrow band filter at X-band to be determined using only fourteen FEM solutions. The difference between the model- and the FEM solutions is less then -lOOdBacross the band. A sample synthesis using generalized simulated annealing is presented. A single pole filter in X-band waveguide is successfully synthesized to illustrate the usefulness of the code. The use of FF techniques results in a computational cost saving of a factor of forty times.
AFRIKAANSE OPSOMMING: 'n Rekenaar werktuig vir numeriese sintese deur middel van optimering word ontwikkel. Slegs twee-poort golfleierkomponente word beskou. Die Eindige Element-metode (EEM) word vir die elektromagnetiese analise gebruik. Meer spesifiek, die frekwensiegebied, elektriese-veld EE-formuleering word gebruik, met eurl-ondersteunende, konstant-tagensiaaljlineêr-normaal, baksteenvormige vektorelemente. Spesiale grensvoorwaardes word by die poorte gebruik. Hierdie grensvoorwaardes neem slegs voortplanting van die dominante modus in ag. Die kwessies rondom die implementering van hierdie EEM word bespreek. Resultate wat met hierdie kode verkry word, vergelyk goed met dié vanuit onafhanklike bronne. 'n Parametriese diskretisasie prosedure in ontwikkel, vir gebruik saam met die genoemde EEM, met die doelom menslike interaksie uit die weg te ruim, tydens die sintese proses. Vinnige Frekwensie (VF) tegnieke word beskryf, met die doelom die berekeningskoste van die sintese te verminder. VF tegnieke verminder die berekeningskoste verbonde aan 'n reeks EEM oplosings binne 'n gegewe frekwensieband, maar verminder nie die koste verbonde aan 'n enkel-frekwensie EEM oplossing nie. Die VF tegnieke wat beskryf word, is die volgende: Asimptotiese Golfvorm Evaluasie (AGE), Model Gebaseerder Asimptotiese Golfvormevaluasie (MGAGE) en Model- Gebaseerde Parameterekstraksie (MGPE). Die resultate wat met hierdie metodes verkry word, word vergelyk om sodoende die mees toepaslike VF tegniek te kies. MGPE word gekies as die mees toepaslike tegniek. 'n Aanpasbase monsteringsalgoritme vir MGPE word beskryf. Die algoritme berus op die verskil tussen twee modelle wat vanaf dieselfde stel punte geskep word, om monsterfrekwensiewaardes te bepaal. Die gebruik van hierdie algoritme lei tot 'n model van 'n nou-, X-band filter, vanuit slegs veertien EEM oplossings. Die verskil tussen hierdie model en enige EEM oplossings binne die band, is kleiner as -lOOdB. 'n Voorbeeld sintese, wat gebruik maak van veralgemeende, gesimuleerde versmelting, word beskryf. 'n Enkel-pool filter by X-band word suksesvol gesintetiseer om die bruikbaarheid van die kode te illustreer. 'n Faktor veertig vermindering III berekeningskostes word behaal deur gebruik te maak van VF tegnieke.
PAPETTI, Stefano. "Sound modeling issues in interactive sonification - From basic contact events to synthesis and manipulation tools". Doctoral thesis, Università degli Studi di Verona, 2010. http://hdl.handle.net/11562/340961.
Texto completoThe work presented in this thesis ranges over a variety of research topics, spacing from human-computer interaction to physical-modeling. What combines such broad areas of interest is the idea of using physically-based computer simulations of acoustic phenomena in order to provide human-computer interfaces with sound feedback which is consistent with the user interaction. In this regard, recent years have seen the emergence of several new disciplines that go under the name of -- to cite a few -- auditory display, sonification and sonic interaction design. This thesis deals with the design and implementation of efficient sound algorithms for interactive sonification. To this end, the physical modeling of everyday sounds is taken into account, that is sounds not belonging to the families of speech and musical sounds.
Nguyen, Huy Tam. "Numerical transformations for area, power, and testability optimization in the synthesis of digtal signal processing ASICs". Diss., Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/13548.
Texto completoFILHO, EMILIO ABUD. "APPLICATION OF VARIATIONAL METHODS AND HEURISTIC FORMULATIONS FOR ANALYZES AND NUMERICAL SYNTHESIS OF RECTANGULAR WAVEGUIDE TRANSFORMERS". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2010. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=16456@1.
Texto completoTransformadores de guia de onda são amplamente empregados no projeto de componentes em onda guiada e são encontrados em praticamente todas as cadeias alimentadoras de antenas e demais estruturas de onda guiada na faixa de microondas. Embora a teoria de transformadores seja conhecida, os requisitos de ordem sistêmica têm levado os projetos de transformadores de guia de onda ao seu limite. Para tal nível de exigência, e considerando o número de variáveis no projeto de transformadores, técnicas numéricas de análise (tais como FDTD e expansão modal dentre outros), e otimização têm sido obrigatoriamente empregadas. Por outro lado, o número de variáveis de um transformador, acaba sendo um processo de alto consumo de tempo computacional, incoerente com o porte e objetivo de custo desses transformadores. Este trabalho propõe uma possibilidade alternativa para a análise mais rápida para essas estruturas, através do emprego de formulações fechadas derivadas de métodos varacionais. Um modelo heurístico é proposto para o caso de descontinuidades em dois planos, sejam para o caso de descontinuidades homogêneas ou para não-homogêneas.
Waveguide transformers are widely used on antenna’s feeder chains and other microwave devices. Although the theory of quarter wavelength transformers is well known, the current electrical performance of such microwave devices has been pushing the waveguide transformers design to its limit. For attending such level of requirements, and considering the number of existing variables on a waveguide transformer design, very accurate numerical techniques has been applied on its analyses, (such as FDTD, mode matching, etc), and optimization techniques as well. On the other hand, such numerical techniques are very memory and/or CPU/time consuming, which do not match with the cost objective of those simple concept transformers. This work proposes an alternative technique, based on close-form models derived from varational theory. A heuristic model is also proposed for attending the two plane transformer case, which can be easily applied for both homogeneous and inhomogeneous structures. Keywords Waveguide;
Incerti, Eric. "Synthèse de sons par modélisation physique de structures vibrantes : applications pour la création musicale par ordinateur". Grenoble INPG, 1996. http://www.theses.fr/1996INPG0115.
Texto completoDucceschi, Michele. "Nonlinear Vibrations of Thin Rectangular Plates : A Numerical Investigation with Application to Wave Turbulence and Sound Synthesis". Palaiseau, École nationale supérieure de techniques avancées, 2014. http://www.theses.fr/2014ESTA0001.
Texto completoThin plate vibrations display a rich and complex dynamics that ranges from linear to strongly nonlinear regimes when increasing the vibration amplitude with respect to the thickness. This thesis is concerned with the development of a numerical code able to simulate without restrictions this large spectrum of dynamical features, described by the von Kármán equations, in the case of flat, homogeneous plates presenting a rectangular geometry. The main application of such a code is to produce gong-like sounds, in the context of sound synthesis by physical modelling. For that, a modal approach is used, in order to reduce the original Partial Differential Equations to a set of couped Ordinary Differential Equations. An energy-conserving, second-order accurate time integration scheme is developed in order to yield a stability condition. The most appealing features of the modal scheme are its accuracy and the possibility of implementing a rich loss mechanism by selecting an appropriate damping factor for each one of the modes. The sound produced by the numerical code is systematically compared to another numerical technique based on Finite Difference techniques. Fundamental aspects of the physics of nonlinear vibrations are also considered in the course of this work. When a plate vibrates in a weakly nonlinear regime, modal couplings produce amplitude-dependent vibrations, internal resonances, instabilities, jumps and bifurcations. The modal scheme is used to construct and analyse the nonlinear response of the plate in the vicinity of its first eigenfrequencies, both in free and forced-damped vibrations, showing as a result the effect of damping and forcing on the nonlinear normal modes of the underlying Hamiltonian system. When plates vibrate in a strongly nonlinear regime, the most appropriate description of the dynamics is given in terms of the statistical properties of the system, because of the vast number of interacting degrees-of-freedom. Theoretically, this framework is offered by the Wave Turbulence theory. Given the large amount of modes activated in such vibrations, a Finite Difference, energy-conserving code is preferred over the modal scheme. Such a scheme allows to produce a cascade of energy including thousands of modes when the plate is forced sinusoidally around one of its lowest eigenfrequencies. A statistical interpretation of the outcome of the simulation is offered, along with a comparison with experimental data and other numerical results found in the literature. In particular, the effect of the pointwise forcing as well as geometrical imperfections of the plates are analysed
Goubault, de Brugière Timothée. "Methods for optimizing the synthesis of quantum circuits Quantum CNOT Circuits Synthesis for NISQ Architectures Using the Syndrome Decoding Problem Quantum circuits synthesis using Householder transformations Synthesizing quantum circuits via numerical optimization Reuse method for quantum circuit synthesis". Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPASG018.
Texto completoTo run an abstract algorithm on a quantum computer, the algorithm must be compiled into a sequence of low-level instructions that can be executed by the processor. The compilation step is crucial because it determines the quantity of resources necessary for the execution of an algorithm. Therefore, the compilation stage must be optimized. In this thesis, we are interested in a brick of compilation: the synthesis of quantum circuits from an abstract specification of an operator.First, we study the case where the unitary matrix of a quantum operator is given to us and we explore the minimization of both quantum resources and classical resources. Even if the simultaneous optimization of these two types of resources seems difficult, we propose better compromises improving the literature.Secondly, we are interested in the class of so-called reversible linear operators. This time we are exclusively interested in the optimization of quantum resources and we improve the state of the art in various cases of quantum metrics (circuit size, circuit depth) and processors (NISQ, fully-connected processors)
Deng, Lei [Verfasser] y Andreas [Akademischer Betreuer] Kempf. "Numerical investigation of uncertainties in experiments for flame structure analysis and particle synthesis / Lei Deng ; Betreuer: Andreas Kempf". Duisburg, 2017. http://d-nb.info/1131551850/34.
Texto completoUguen, Yohann. "High-level synthesis and arithmetic optimizations". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEI099.
Texto completoHigh-level synthesis (HLS) tools offer increased productivity regarding FPGA programming. However, due to their relatively young nature, they still lack many arithmetic optimizations. This thesis proposes safe arithmetic optimizations that should always be applied. These optimizations are simple operator specializations, following the C semantic. Other require to a lift the semantic embedded in high-level input program languages, which are inherited from software programming, for an improved accuracy/cost/performance ratio. To demonstrate this claim, the sum-of-product of floating-point numbers is used as a case study. The sum is performed on a fixed-point format, which is tailored to the application, according to the context in which the operator is instantiated. In some cases, there is not enough information about the input data to tailor the fixed-point accumulator. The fall-back strategy used in this thesis is to generate an accumulator covering the entire floating-point range. This thesis explores different strategies for implementing such a large accumulator, including new ones. The use of a 2's complement representation instead of a sign+magnitude is demonstrated to save resources and to reduce the accumulation loop delay. Based on a tapered precision scheme and an exact accumulator, the posit number systems claims to be a candidate to replace the IEEE floating-point format. A throughout analysis of posit operators is performed, using the same level of hardware optimization as state-of-the-art floating-point operators. Their cost remains much higher that their floating-point counterparts in terms of resource usage and performance. Finally, this thesis presents a compatibility layer for HLS tools that allows one code to be deployed on multiple tools. This library implements a strongly typed custom size integer type along side a set of optimized custom operators
Najahi, Mohamed amine. "Synthesis of certified programs in fixed-point arithmetic, and its application to linear algebra basic blocks : and its application to linear algebra basic blocks". Thesis, Perpignan, 2014. http://www.theses.fr/2014PERP1212.
Texto completoTo be cost effective, embedded systems are shipped with low-end micro-processors. These processors are dedicated to one or few tasks that are highly demanding on computational resources. Examples of widely deployed tasks include the fast Fourier transform, convolutions, and digital filters. For these tasks to run efficiently, embedded systems programmers favor fixed-point arithmetic over the standardized and costly floating-point arithmetic. However, they are faced with two difficulties: First, writing fixed-point codes is tedious and requires that the programmer must be in charge of every arithmetical detail. Second, because of the low dynamic range of fixed-point numbers compared to floating-point numbers, there is a persistent belief that fixed-point computations are inherently inaccurate. The first part of this thesis addresses these two limitations as follows: It shows how to design and implement tools to automatically synthesize fixed-point programs. Next, to strengthen the user's confidence in the synthesized codes, analytic methods are suggested to generate certificates. These certificates can be checked using a formal verification tool, and assert that the rounding errors of the generated codes are indeed below a given threshold. The second part of the thesis is a study of the trade-offs involved when generating fixed-point code for linear algebra basic blocks. It gives experimental data on fixed-point synthesis for matrix multiplication and matrix inversion through Cholesky decomposition
Abou, Taam Salam. "Dispositifs de synthèse vasculaire : analyse, modélisation, applications au réseau artériel périphérique et aux fistules artérioveineuses pour abord d’hémodialyse : ouverture sur l’étude de nouveaux outils de réparation et modulation vasculaire". Electronic Thesis or Diss., Sorbonne université, 2019. http://www.theses.fr/2019SORUS582.
Texto completoThis study presents the physiological and pathological aspects of the arterial blood flow and draws up various methods of vascular repair. It focuses on innovative suture solutions for circulatory system repair. Various blood flow restoration strategies, retrieved from the surgical practice, were examined on the basis of a new digital model of the vascular network simplified into 55 arteries, in both 0D and 1D. We thus studied several techniques of blood flow restoration to the lower limb during an iliac artery obliteration, those based on different types of anatomical and extra-anatomical bypasses, but also one based on a stent being inserted in the original network. At each attempt, we found the flow to be restored downstream and congruent to the clinical observations, thus confirming our digital network. We have also applied its 0D tools to an arteriovenous fistula. With the aim of providing our model as a tool to assist the surgeon’s decision making, we then have adjusted various parameters in order to anticipate the repercussions of surgical procedures to treat both stenosis and hypertension
Antoine, Mathieu. "Les techniques algorithmiques du codage Octree appliquées à l'analyse de volumes tridimensionnels de données numériques". Grenoble 1, 1988. http://www.theses.fr/1988GRE10042.
Texto completoTamburello, David A. "Parametric analysis of the synthetic air jet using numerical simulations". Thesis, Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/17075.
Texto completoAl, Rikabi Fouad T. "Experimental and Numerical Study on Synthetic Fiber-Reinforced Concrete Pipes". Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1596624831718006.
Texto completoJarrin, Nicolas. "Synthetic inflow boundary conditions for the numerical simulation of turbulence". Thesis, University of Manchester, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.676725.
Texto completoFellner, Johannes Josef. "Numerical study on orthometric heights using a synthetic Earth gravity model". Thesis, Curtin University, 2011. http://hdl.handle.net/20.500.11937/1047.
Texto completoMeyrand, Louis. "Modes non linéaires : approches réduites par PGD/HBM et applications aux réponses forcées". Thesis, Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0561.
Texto completoIn the field of structural vibrations, the increasing performance of computers allows to handle more and more complex and realistic systems. This inevitably leads to the consideration of nonlinear phenomena. The industrial context is also characterized by the need to solve ever larger systems. The work presented in this PhD thesis focuses on the development of algorithmic processes to effectively solve large scale problems in nonlinear dynamics. To do this, the choice is made to calculate the Nonlinear Normal Modes (NNMs) of the structures. These objects are not only representative of the vibratory state of the system but also of its nonlinearities.After having proposed a compact and economical method for calculating NNMs, this manuscript then proposes to exploit the data contained in these objects to quickly plot the response of systems subjected to external forces. The implemented methods perform only a few calculations to achieve this
Coates, Tim. "Numerical simulation of unconventional aero-engine exhaust systems for aircraft". Thesis, Loughborough University, 2014. https://dspace.lboro.ac.uk/2134/16365.
Texto completoWang, Zhuo. "Numerical analysis of massive separation control on turbomachine blades using synthetic jet". Phd thesis, [S.l. : s.n.], 2003. http://elib.tu-darmstadt.de/diss/000308.
Texto completoWeiler, Justin D. "Numerical Simulation of Flame-Vortex Interactions in Natural and Synthetic Gas Mixtures". Thesis, Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4774.
Texto completoCastro, Nicholas D. "Numerical Modeling of Synthetic Jets in Quiescent Air with Moving Boundary Conditions". VCU Scholars Compass, 2005. http://scholarscompass.vcu.edu/etd/1466.
Texto completoMacDonald, Nicholas Roy. "Bridging the gap : synthetic radio observations of numerical simulations of extragalactic jets /". Halifax, N.S. : Saint Mary's University, 2008.
Buscar texto completoLi, Shuo. "A Numerical Study of Micro Synthetic Jet and Its Applications in Thermal Management". Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7539.
Texto completoMenon, Ashwin. "Numerical investigation of synthetic jet based flow control for vertical axis wind turbines". Thesis, Rensselaer Polytechnic Institute, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=1568426.
Texto completoThis numerical study focuses on the implementation of active flow control using synthetic jets on vertical-axis wind turbine (VAWT) blades. This study demonstrates that synthetic-jet based flow control improves the efficiency of the turbine and reduces the risk of structural fatigue.
In VAWTs, the blades experience a significant variation in the angle of attack over each rotation cycle and associated with it are sudden changes in the flow-induced loading on the blades. For example, a sudden variation in blade loading is experienced due to the detachment of the leading edge vortex at high angles of attack. This is in-turn reduces the axial force and hence the overall power output of the turbine. Additionally, such force variations lead to structural fatigue and possibly failure. Current simulations consider a cross-section of a three-blade VAWT model (with straight blades). VAWT models with two different airfoils, NACA 0018 and DU 06-W-200, are considered at tip-speed-ratios of 2 and 3. In these simulations, unsteady, Reynolds-averaged Navier-Stokes equations along with the Spalart-Allmaras turbulence model are employed, where stabilized finite element method is utilized along with an implicit time-integration scheme.
The idea of using synthetic jets is to control the variation in flow-induced loading during each rotation cycle. At first the dominant location of the flow separation is determined for both airfoils. The jets are then placed at this location. Jet parameters of blowing ratio and reduced frequency are specified within a range (i.e., O(0.5-1.5) and O(1-10), respectively) and their effects on jet performance are studied. The jets are activated only in a selected portion of the rotation cycle. This is referred to as the partial cycle control in contrast to the full cycle (the latter is found to be detrimental). For given jet parameters, simulations results are used to determine whether the jets improve axial force, flow separation and blade-vortex interaction. At blowing ratio of 1.5 and reduced frequency of 5, we observe above 12% increase in the average axial force over the rotation cycle for both airfoils.
Zadvitskiy, Georgiy. "Experimental and numerical study of turbulence in fusion plasmas using reflectometry synthetic diagnostics". Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0074/document.
Texto completoPlasma turbulence studies are essential for successful operation of magnetic confinement fusion devices. Ultra-Fast Swept Reflectometry (USFR), a diagnostic widely used for the measurement of turbulence radial wave-number spectra. While the interpretation of reflectometry data is quite straightforward for small levels of turbulence, it becomes much trickier for larger levels as the reflectometer answer is no longer linear with the turbulence level. It has been shown for instance that resonances due to probing field trapping can appear in turbulent plasma and produce jumps of the signal phase. In the plasma edge region the turbulence level is usually high and can lead to a non-linear regime of the reflecetometer response. The loss of probing beam coherency and beam widening when the probing beam crosses the edge turbulence layer can affect USFR core measurements. Edge turbulence with a long correlation length leads to small beam widening and strong distortion of the probing wave phase. However backscattering effects from turbulence with short correlation lengths are also able to cause reflectometer signal change. To study turbulence wave-number spectra together with reflectometer signal phase variations, signal amplitude variations can be analyzed. Unlike signal phase variation, amplitude does not suffer from resonant jumps, and can give more clear qualitative evaluation of turbulence structure. In the case when the turbulence amplitude peaked in the edge region, it can be detected as spectral peak near local Bragg resonance wave-number. USFR with a set of receiving antennas arranged poloidally was proposed to obtain more information on the edge turbulence properties. A displacement of the spectral peak appears when the receiving antenna is misaligned with the emitting one. In perspective peak displacement measurements can provide additional information on probing beam shaping and turbulence properties and help in coherent mode observation. A 2D full wave code was applied as a synthetic diagnostic to Gysela gyro-kinetic for study of Tore-Supra tokamak core turbulence. Radial correlation lengths computed from the amplitude of multi-channel fixed frequency reflectometry signals have shown good agreement with the turbulence correlation length. The synthetic diagnostic was then applied to analyze the correlation length and wave-number spectra obtained by USFR in the ASDEX-Upgrade tokamak. A comparison between 1D and 2D results have shown different behavior. However correlation lengths measured with UFSR signals are in the same order with turbulence ones
Miró, Jané Arnau. "Flow and heat transfer of impinging synthetic jets". Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/667300.
Texto completoEls jets sintètics (SJ) són produïts pel moviment oscil·latori d'una membrana a l'interior d'una cavitat, cosa que fa que el líquid entri i surti per un petit orifici. Això es tradueix en un jet que és capaç de transferir energia cinètica i impuls a un medi fluid sense la necessitat d'una font externa. És per això que els SJ són interessants i tindran un paper clau en una àmplia gamma d'aplicacions rellevants, com ara el control actiu de flux, el refredament tèrmic o la barreja de combustible. Des del punt de vista fenomenològic, els SJ estan formats per patrons de flux elaborats per la seva naturalesa no lineal i, sota certes condicions, es poden observar fluxos complexos i inestables. Aquesta tesis està centrada en la investigació del flux de fluids i el rendiment tèrmic dels jets sintètics. S'estudien dues geometries diferents d’actuadors de SJ (és a dir, ranurats i circulars). Els jets en ambdues configuracions estan confinats per dues plaques isotèrmiques paral·leles amb una diferència de temperatura imposada i afecten a una placa escalfada situada a una certa distància de l'orifici de l'actuador. Les equacions tridimensionals inestables de Navier-Stokes es resolen per un nombre de Reynolds utilitzant simulacions numèriques precises en el temps. A més, es desenvolupa un model detallat de l'actuador que utilitza la formulació arbitrària lagrangiana-euleriana (ALE) per explicar el moviment de la membrana de l'actuador. Aquest model, basat en els números de govern del flux, s'utilitza per realitzar els anàlisis numèrics. Els fluxos obtinguts en ambdues configuracions són notablement diferents i tridimensionals per a gairebé tots els números de Reynolds considerats. El jet en la configuració ranurada està format per un parell de vòrtexs que experimenten una transició turbulenta que finalment formen el jet. El flux extern està dominat per dues recirculacions principals amb els seus homòlegs dins de la cavitat de l'actuador. Una nova estructura, observada en els jets ranurats confinats, apareix com una interacció del flux amb la paret inferior i provoca un canvi en els mecanismes de transferència de calor del jet. D'altra banda, el jet en la configuració circular presenta tres regions de flux diferents que s'han identificat segons la literatura: l'anell de vòrtex principal, el jet final i el nucli potencial. En aquest cas, el flux extern està dominat per l'anell de vòrtex principal i el jet de sortida, presentant així un comportament diferent de morfologia i transferència de calor que la configuració ranurada. Un anàlisi detallat de les trajectòries de vòrtex ha demostrat que els vòrtexs de la configuració circular arriben a la paret superior abans que els seus homòlegs ranurats. Les distribucions d'energia cinètica turbulenta a l'expulsió, entre altres, han revelat que el flux del jet circular es concentra majoritàriament a prop de la línia central del jet, mentre que és més estès per a la configuració ranurada. Per aquestes raons, a la mateixa velocitat d'ejecció del jet i geometria de l'actuador, la formació de SJ en la configuració circular pot produir-se a freqüències més altes que a la configuració ranurada. L'anàlisi de la temperatura de sortida dels SJ ha demostrat que assumir un perfil uniforme és raonable si el nombre de Reynolds és prou elevat. A més, la temperatura del jet de sortida és significativament superior a la temperatura de la placa freda. Les dues configuracions presenten diferents comportaments a causa de les diferències en el flux. L’anàlisi de la transferència de calor a la paret calenta ha revelat que la configuració circular arriba a un màxim de transferència de calor més gran que la configuració ranurada, però, la transferència de calor es desaccelera més ràpidament en la configuració circular quan s’allunya de la línia central. Finalment, es proposen correlacions per a la transferència de calor a la paret calenta i la temperatura de sortida amb el nombre de Reynolds. Poden ser útils per incloure els efectes de la cavitat quan s’utilitzen models simplificats que no tenen en compte la cavitat de l’actuador.
Mahieux, Bruno. "Contribution à l'optimisation en masse de structures complexes sous contraintes vibratoires : application à la conception des planches de bord en phase d'études préliminaires". Valenciennes, 1996. http://www.theses.fr/1996VALE0031.
Texto completoAkcayoz, Eray. "Numerical Investigation Of Flow Control Over An Airfoil With Synthetic Jets And Its Optimization". Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609979/index.pdf.
Texto completothe jet velocity, the jet location, the jet angle and the jet frequency are optimized to maximize the lift to drag ratio. The optimization study is performed for a constant value of jet power coefficient. The jet slot size is used as a dependent parameter in the optimization studies. The optimization study has shown that the jet velocity and the jet location are the dominant synthetic jet parameters. The optimum synthetic jet angle is observed to be increasing as the angle of attack increases. The optimum jet location is observed to be moving through the leading edge as angle of attack increases for the separated flows. It is observed that the application of the synthetic jet delays the flow separation on the suction side of the airfoil and increases the lift to drag ratio significantly especially at post stall angles of attack. The application of the synthetic jet is observed to be less effective for attached flows.
Zhou, Jue. "Numerical investigation of the behaviour of circular synthetic jets for effective flow separation control". Thesis, University of Manchester, 2010. https://www.research.manchester.ac.uk/portal/en/theses/numerical-investigation-of-the-behaviour-of-circular-synthetic-jets-for-effective-flow-separation-control(6faae20e-82d6-4efb-8044-c02b089d667c).html.
Texto completoValenzuela, Calva Fernando. "Numerical investigation of the interaction of synthetic jets with a laminar boundary layer and the effect of jet orientation". Thesis, University of Manchester, 2016. https://www.research.manchester.ac.uk/portal/en/theses/numerical-investigation-of-the-interaction-of-synthetic-jets-with-a-laminar-boundary-layer-and-the-effect-of-jet-orientation(5cc80987-a9e1-48ac-9e0f-18067c5f48fe).html.
Texto completoCasavecchia, Benedetta. "Studying synthetic column density maps and absorption spectra from galactic wind models". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2022. http://amslaurea.unibo.it/25361/.
Texto completoNatarajan, Jayaprakash. "Experimental and numerical investigation of laminar flame speeds of H₂/CO/CO₂/N₂ mixtures". Diss., Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/22685.
Texto completoCasaca, Wallace Correa de Oliveira. "Restauração de imagens digitais com texturas utilizando técnicas de decomposição e equações diferenciais parciais /". São José do Rio Preto : [s.n.], 2010. http://hdl.handle.net/11449/94247.
Texto completoBanca: Evanildo Castro Silva Júnior
Banca: Alagacone Sri Ranga
Resumo: Neste trabalho propomos quatro novas abordagens para tratar o problema de restauração de imagens reais contendo texturas sob a perspectiva dos temas: reconstrução de regiões danificadas, remoção de objetos, e eliminação de ruídos. As duas primeiras abor dagens são designadas para recompor partes perdias ou remover objetos de uma imagem real a partir de formulações envolvendo decomposiçãode imagens e inpainting por exem- plar, enquanto que as duas últimas são empregadas para remover ruído, cujas formulações são baseadas em decomposição de três termos e equações diferenciais parciais não lineares. Resultados experimentais atestam a boa performace dos protótipos apresentados quando comparados à modelagens correlatas da literatura.
Abstract: In this paper we propose four new approaches to address the problem of restoration of real images containing textures from the perspective of reconstruction of damaged areas, object removal, and denoising topics. The first two approaches are designed to reconstruct missing parts or to remove objects of a real image using formulations based on image de composition and exemplar based inpainting, while the last two other approaches are used to remove noise, whose formulations are based on decomposition of three terms and non- linear partial di®erential equations. Experimental results attest to the good performance of the presented prototypes when compared to modeling related in literature.
Mestre
Blake, Jack. "Domain decomposition methods for nuclear reactor modelling with diffusion acceleration". Thesis, University of Bath, 2016. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.698988.
Texto completoÅgren, Jonas. "Regional Geoid Determination Methods for the Era of Satellite Gravimetry : Numerical Investigations Using Synthetic Earth Gravity Models". Doctoral thesis, KTH, Infrastructure, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-55.
Texto completoIt is the purpose of this thesis to investigate different regional geoid determination methods with respect to their feasibility for use with a future GOCE satellite-only Earth Gravity Model (EGM). This includes investigations of various techniques, which involve different approximations, as well as the expected accuracy. Many, but not all, of these tasks are tested by means of Synthetic Earth Gravity Models (SEGMs). The study is limited to remove-compute-restore methods using Helmert condensation and to Sjöberg's combined approach (method with additive corrections).
First, a number of modifications of Stokes' formula are tested with respect to their compatibility with a GOCE EGM having negligible commission error. It is concluded that the least squares modification method should be preferred.
Next, two new point-mass SEGMs are constructed in such a way that the resulting models have degree variances representative for the full and topographically reduced gravity fields, respectively. These SEGMs are then used to test different methods for modified Stokes' integration and downward continuation. It is concluded that the combined method requires dense observations, obtained from the given surface anomalies by interpolation using a reduction for all known density anomalies, most notably the topography. Examples of other conclusions are that the downward continuation method of Sjöberg (2003a) performs well numerically.
To be able to test topographic corrections, another SEGM is constructed starting from the reduced point-mass model, to which the topography, bathymetry and isostatic compensation are added. This model, which is called the Nordic SEGM, is then applied to test one strict and one more approximate approach to Helmert's condensation. One conclusion here is that Helmert's 1st method with the condensation layer 21 km below sea level should be preferred to Helmert's 2nd condensation strategy.
The thesis ends with a number of investigations of Sjöberg's combined approach to geoid determination, which include tests using the Nordic SEGM. It is concluded that the method works well in practice for a region like Scandinavia. It is finally shown how the combined strategy may preferably be used to estimate height anomalies directly.