Dissertations / Theses: 'Transfer integral'

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Masuda, Hiroshi. "Film condensation heat transfer of low integral-fin tube." Thesis, Queen Mary, University of London, 1985. http://qmro.qmul.ac.uk/xmlui/handle/123456789/1585.

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For condensation on horizontal low-finned tubes, the dependence of heat-transfer performance on fin spacing has been investigated experimentally for condensation of refrigerant 113 and ethylene glycol. Fourteen tubes have been used with inside diameter 9.78 mm and working length exposed to vapour 102 mm. The tube had rectangular section fins having the same width and height (0.5 mm and 1.59 mm) and with the spacing between fins varying from 0.25 mm to 20 mm. The diameter of the tube at the fin root was 12.7 mm. Tests were also made using a plain tube having the same inside diameter and an outside diameter equal to that at the root of the fins for the finned tubes. All tests were made at near atmospheric pressure with vapour flowing vertically downward with velocities of 0.24 m/s and 0.36 m/s for refrigerant 113 and ethylene glycol respectively. Optimum fin spacings were found at 0.5 mm and 1.0 mm for refrigerant 113 and ethylene glycol respectively. In earlier experiments for steam using the same tubes, the optimum fin spacing was found to be 1.5 mm. Maximum enhancement ratios of vapour-side heat-transfer coefficient (vapour-side coefficient for a finned tube / vapour-side coefficient for a plain tube. for the same vapour-side temperature difference) were 7.5, 5.2 and 3.0 for refrigerant 113, ethylene glycol and steam respectively. Enhancement phenomena have also been studied theoretically. Consideration has been given to a role of surface tension forces on the motion and configuration of condensate film. On the basis of this study, several semi-empirical equations, to predict heat-transfer performance, have been obtained. These are considered to represent recent reliable data (present and other recent works) satisfactorily.

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Steptoe, William James. "Integral boundary layer heat transfer prediction on turbine blades." Thesis, Massachusetts Institute of Technology, 1989. http://hdl.handle.net/1721.1/42188.

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Fritzgerald, Claire Louise. "Forced-convection condensation heat-transfer on horizontal integral-fin tubes including effects of liquid retention." Thesis, Queen Mary, University of London, 2011. http://qmro.qmul.ac.uk/xmlui/handle/123456789/2353.

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Accurate and repeatable heat-transfer data are reported for forced-convection filmwise condensation of steam and ethylene glycol flowing vertically downward over two single, horizontal instrumented integral-fin tubes and one plain tube. Vapour-side, heat-transfer coefficients were obtained by direct measurement of the tube wall temperature using specially manufactured, instrumented tubes with thermocouples embedded in the tube walls. Both tubes had fin height of 1.6 mm and fin root diameter of 12.7 mm, with fin thickness and spacing of 0.3 mm and 0.6 mm, respectively for the first tube and 0.5 mm and 1.0 mm respectively for the second. Tests were performed at atmospheric pressure for steam with nominal vapour velocities from 2.4 m/s to 10.5 m/s and at three pressures below atmospheric with nominal vapour velocities from 8.4 m/s to 57 m/s for steam and 13 m/s to 82 m/s for ethylene glycol. The data show that both the finned tubes provide an increase in heat flux at the same vapour-side temperature difference with increasing vapour velocity. Visual observations were made and photographs obtained of the condensate retention angle at each combination of vapour velocity and pressure. It was observed that the curvature of the meniscus was distorted by the increase in vapour velocity and in many cases, the extent of condensate flooding changed compared to its value in the quiescent vapour case. In parallel, experiments involving simulated condensation on finned tubes were conducted using horizontal finned tubes in a vertical wind tunnel. Condensate was simulated by liquid (water, ethylene glycol and R-113) supplied to the tube via small holes between the fins along the top of the tube. Downward air velocities up to 24 m/s were used and retention angles were determined from still photograph. Eight tubes with a diameter at the fin root of 12.7 mm were tested. Five tubes of which had fin height of 0.8 mm and spacing between fins of 0.5 mm, 0.75 mm, 1.0 mm, 1.25 mm and 1.5 mm and three tubes had fin height 1.6 mm with fin spacings 0.6 mm, 1.0 mm and 1.5 mm. The results were repeatable on different days and suggested, for all tubes and fluids, that the retention angle asymptotically approached a value around 80o to 85o (from either lower or higher values at zero vapour velocity) with increase in air velocity. Good agreement was found with observations taken during the condensation experiments.

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Czuprynski, Kenneth Daniel. "Numerical analysis in energy dependent radiative transfer." Diss., University of Iowa, 2017. https://ir.uiowa.edu/etd/5925.

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The radiative transfer equation (RTE) models the transport of radiation through a participating medium. In particular, it captures how radiation is scattered, emitted, and absorbed as it interacts with the medium. This process arises in numerous application areas, including: neutron transport in nuclear reactors, radiation therapy in cancer treatment planning, and the investigation of forming galaxies in astrophysics. As a result, there is great interest in the solution of the RTE in many different fields. We consider the energy dependent form of the RTE and allow media containing regions of negligible absorption. This particular case is not often considered due to the additional dimension and stability issues which arise by allowing vanishing absorption. In this thesis, we establish the existence and uniqueness of the underlying boundary value problem. We then proceed to develop a stable numerical algorithm for solving the RTE. Alongside the construction of the method, we derive corresponding error estimates. To show the validity of the algorithm in practice, we apply the algorithm to four different example problems. We also use these examples to validate our theoretical results.

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Shaikh, Shaunak Mehboob. "Light Harvesting and Energy Transfer in Metal-Organic Frameworks." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/104022.

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A key component of natural photosynthesis are the antenna chromophores (chlorophylls and carotenoids) that capture solar energy and direct it towards the reaction centers of photosystems I and II. Highlighted by highly-ordered crystal structures and synthetic tunability via crystal engineering, metal–organic frameworks (MOFs) have the potential to mimic the natural photosynthetic systems in terms of the efficiency and directionality of energy transfer. Owing to their larger surface areas, MOFs have large absorption cross sections, which amplifies the rate of photon collection. Furthermore, MOFs can be constructed using analogues of chlorophyll and carotenoids that can participate in long-range energy transfer. Herein, we aimed to design photoactive MOFs that can execute one of the critical steps involved in photosynthesis - photon collection and subsequent energy transfer. The influence of spatial arrangement of chromophores on the efficiency and directionality of excitation energy transfer (EET) was investigated in a series of mixed-ligand pyrene- and porphyrin-based MOFs. Due to the significant overlap between the emission spectrum of 1,3,6,8-tetrakis(p-benzoic acid)pyrene (TBAPy) and the absorption spectrum of meso-tetrakis(4-carboxyphenyl)porphyrin (TCPP), the co-assembly of these two ligands in a MOF should enable facile energy transfer. Bearing this in mind, three TBAPy-based MOFs with markedly different network topologies (ROD-7, NU-901, and NU-1000) were chosen and a small number of TCPP units were incorporated in their backbone. To gain insight into the photophysical properties of mixed-ligand MOFs, we conducted time-resolved and steady-state fluorescence measurements on them. Stern-Volmer analysis was performed on the fluorescence lifetime data of mixed-ligand MOFs to determine the quenching constants. The quenching constant values for ROD-7, NU-901, NU-1000, and TBAPy solution were found to be 15.03 ± 0.82 M-1, 10.25 ± 0.99 M-1, 8.16 ± 0.41 M-1, and 3.35 ± 0.30 respectively. In addition, the ratio of the fluorescence intensities of TCPP and TBAPy was used to calculate the EET efficiencies in each of the three MOFs. EET efficiencies were in the following order: ROD-7 > NU-901 > NU-1000 > TBAPy-solution. Based on the trends observed for quenching constants and EET efficiencies, two conclusions were drawn: (1) the ligand-to-ligand energy transfer mechanism in MOFs outperforms the diffusion-controlled mechanism in solution phase, (2) energy transfer in MOFs is influenced by their structural parameters and spectral overlap integrals. The enhanced EET efficiency in ROD-7 is attributed to shorter interchromophoric distance, larger orientation factor, and larger spectral overlap integral. Directionality of energy transfer in these MOFs was assessed by calculating excitonic couplings between neighboring TBAPy linkers using the atomic transition charges approach. Rate constants of EET (kEET) along different directions were determined from the excitonic couplings. Based on the kEET values, ROD-7 is expected to demonstrate highly anisotropic EET along the stacking direction. In order to explore the mechanistic aspects of EET in porphyrin-based MOFs, we studied the energy transfer characteristics of PCN-223, a zirconium-based MOF containing TCPP ligands. After performing structural characterization, the photophysical properties of PCN-223 and free TCPP were investigated using steady state and time-resolved spectroscopy. pH-dependent fluorescence quenching experiments were performed on both the MOF and ligand. Stern-Volmer analysis of quenching data revealed that the quenching rate constants for PCN-223 and TCPP were 8.06 ± 1011 M-1s-1 and 2.71 ± 1010 M-1s-1 respectively. The quenching rate constant for PCN-223 is, therefore, an order of magnitude larger than that for TCPP. Additionally, PCN-223 demonstrated a substantially higher extent of quenching (q = 93%) as compared to free TCPP solution (q = 51%), at similar concentrations of quencher. The higher extent of quenching in MOF is attributed to energy transfer from neutral TCPP linkers to N-protonated TCPP linkers. Using the Förster energy transfer model, the rate constant of EET in PCN-223 was calculated. The magnitude of rate constant was in good agreement with the kEET values reported for other porphyrin-based MOFs. Nanosecond transient absorption measurements on PCN-223 revealed the presence of a long-lived triplet state (extending beyond 200 μs) that exhibits the characteristic features of a TCPP-based triplet state. The lifetime of MOF is shorter than that of free ligand, which may be attributed to triplet-triplet energy transfer in the MOF. Lastly, femtosecond transient absorption spectroscopy was employed to study the ultrafast photophysical processes taking place in TCPP and PCN-223. Kinetic analysis of the femtosecond transient absorption data of TCPP and PCN-223 showed the presence of three distinct time components that correspond to: (a) solvent-induced vibrational reorganization of excitation energy, (b) vibrational cooling, and (c) fluorescence. Materials that allow control over the directionality of energy transfer are highly desirable. Core-shell nanocomposites have recently emerged as promising candidates for achieving long-distance, directional energy transfer. For our project, we aim to employ UiO-67-on-PCN‐222 composites as model systems to explore the possibility of achieving directional energy transfer in MOF-based core-shell structures. The core–shell composites were synthesized by following a previously published procedure. Appropriate amounts of Ruthenium(II) tris(5,5′-dicarboxy-2,2′-bipyridine), RuDCBPY, were doped in the shell layer to produce a series of Ru-UiO-67-on-PCN‐222 composites with varying RuDCBPY loadings (CS-1, CS-2, and CS-3). The RuDCBPY-doped core–shell composites were characterized by powder X-ray diffraction (PXRD), scanning electron microscopy (SEM) imaging, Nitrogen adsorption-desorption isotherms, and diffuse reflectance spectroscopy. Efforts are currently underway to quantify RuDCBPY loadings in CS-1, CS-2, and CS-3. After completing structural characterization, the photophysical properties of CS-1, CS-2, and CS-3 will be investigated with the help of time-resolved and steady-state fluorescence spectroscopy. Doctor of Philosophy The pigment−protein complexes in natural photosynthetic units (also known as light harvesting antennas) efficiently capture solar energy and transfer this energy to reaction centers that carry out water splitting reactions. The collective chromophoric behavior of antennas can be replicated by metal-organic frameworks (MOFs). MOFs are crystalline, self-assembled materials composed of metal clusters connected by organic molecules. In this dissertation, we study the factors that govern the energy transfer and light harvesting capabilities of MOFs. In chapter 2, we examined the role of 3D structure of MOFs in energy transfer. In chapter 3, we investigated the influence of pH and temperature on the photophysical properties of MOFs. In chapter 4, we explored the possibility of energy transfer in novel MOF-on-MOF composites. This work is intended to pave the way for the construction of highly efficient MOF-based materials that can serve as the light harvesting and energy-transfer components in solar energy conversion devices.

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Rogozhin, Alexander. "Approximation Methods for Two Classes of Singular Integral Equations." Doctoral thesis, Universitätsbibliothek Chemnitz, 2003. http://nbn-resolving.de/urn:nbn:de:swb:ch1-200300091.

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The dissertation consists of two parts. In the first part approximate methods for multidimensional weakly singular integral operators with operator-valued kernels are investigated. Convergence results and error estimates are given. There is considered an application of these methods to solving radiation transfer problems. Numerical results are presented, too. In the second part we consider a polynomial collocation method for the numerical solution of a singular integral equation over the interval. More precisely, the operator of our integral equation is supposed to be of the form \ $aI + b \mu^{-1} S \mu I $\ with \ $S$\ the Cauchy singular integral operator, with piecewise continuous coefficients \ $a$\ and \ $b,$\ and with a Jacobi weight \ $\mu.$\ To the equation we apply a collocation method, where the collocation points are the Chebyshev nodes of the first kind and where the trial space is the space of polynomials multiplied by another Jacobi weight. For the stability and convergence of this collocation method in weighted \ $L^2$\ spaces, we derive necessary and sufficient conditions. Moreover, the extension of these results to an algebra generated by the sequences of the collocation method applied to the mentioned singular integral operators is discussed and the behaviour of the singular values of the discretized operators is investigated Die Dissertation beschäftigt sich insgesamt mit der numerischen Analysis singulärer Integralgleichungen, besteht aber aus zwei voneinander unabhängigen Teilen. Der este Teil behandelt Diskretisierungsverfahren für mehrdimensionale schwach singuläre Integralgleichungen mit operatorwertigen Kernen. Darüber hinaus wird hier die Anwendung dieser allgemeinen Resultate auf ein Strahlungstransportproblem diskutiert, und numerische Ergebnisse werden präsentiert. Im zweiten Teil betrachten wir ein Kollokationsverfahren zur numerischen Lösung Cauchyscher singulärer Integralgleichungen auf Intervallen. Der Operator der Integralgleichung hat die Form \ $aI + b \mu^{-1} S \mu I $\ mit dem Cauchyschen singulären Integraloperator \ $S,$\ mit stückweise stetigen Koeffizienten \ $a$\ und \ $b,$\ und mit einem klassischen Jacobigewicht \ $\mu.$\ Als Kollokationspunkte dienen die Nullstellen des n-ten Tschebyscheff-Polynoms erster Art und Ansatzfunktionen sind ein in einem geeigneten Hilbertraum orthonormales System gewichteter Tschebyscheff-Polynome zweiter Art. Wir erhalten notwendige und hinreichende Bedingungen für die Stabilität und Konvergenz dieses Kollokationsverfahrens. Außerdem wird das Stabilitätskriterium auf alle Folgen aus der durch die Folgen des Kollokationsverfahrens erzeugten Algebra erweitert. Diese Resultate liefern uns Aussagen über das asymptotische Verhalten der Singulärwerte der Folge der diskreten Operatoren

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Pond, Ian. "Toward an Understanding of the Breakdown of Heat Transfer Modeling in Reciprocating Flows." ScholarWorks @ UVM, 2015. http://scholarworks.uvm.edu/graddis/477.

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Reynolds average Navier-Stokes (RANS) modeling has established itself as a critical design tool in many engineering applications, thanks to its superior computational efficiency. The drawbacks of RANS models are well known, but not necessarily well understood: poor prediction of transition, non-equilibrium flows, mixing and heat transfer, to name the ones relevant to our study. In the present study, we use a direct numerical simulation (DNS) of a reciprocating channel flow driven by an oscillating pressure gradient to test several low- and high-Reynolds' RANS models. Temperature is introduced as a passive scalar to study heat transfer modeling. Low-Reynolds' models manage to capture the overall physics of wall shear and heat flux well, yet with some phase discrepancies, whereas high-Reynolds' models fail. We have derived an integral method for wall shear and wall heat flux analysis, which reveals the contributing terms for both metrics. This method shows that the qualitative agreement appears more serendipitous than driven by the ability of the models to capture the correct physics. The integral method is shown to be more insightful in the benchmarking of RANS models than the typical comparisons of statistical quantities. This method enables the identification of the sources of discrepancies in energy budget equations. For instance, in the wall heat flux, one model is shown to have an out of phase dynamic behavior when compared to the benchmark results, demonstrating a significant issue in the physics predicted by this model. Our study demonstrates that the integral method applied to RANS modeling yields information not previously available that should guide the derivation of physically more accurate models.

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Ikhwan, Nur. "Numerical simulations of the effect of turbulence intensity and integral length scale on stagnation region heat transfer." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0035/MQ62389.pdf.

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社本, 英二, Eiji SHAMOTO, 励. 樋野 та ін. "CNC装置の内部情報を利用した工作機械の熱変形推定". 日本機械学会, 2003. http://hdl.handle.net/2237/9005.

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Venezuela, Antonio Luís. "Modelagem analítico-numérica do escoamento laminar convectivo em tubos associada à filtração tangencial." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/18/18147/tde-17012011-141704/.

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Nesta tese de doutorado é utilizada a técnica híbrida analítico-numérica, conhecida internacionalmente por GITT (Generalized Integral Transform Technique), para modelagem e simulação da equação de conservação das espécies químicas, na investigação do escoamento laminar incompressível, newtoniano e permanente em tubos permeáveis. O escoamento é aplicado ao processo de filtração tangencial com membranas e foram realizados dois estudos relacionados à equação convectiva-difusiva elíptica e parabólica, para as quais são utilizadas as mesmas condições de fronteira. Na modelagem a velocidade na parede permeável é considerada uniforme e os perfis de velocidade para a região de entrada do escoamento são obtidos na literatura. O modelo matemático utiliza originalmente uma expressão para a espessura da camada limite de concentração, com uma metodologia que determina a taxa assintótica, com a qual se estabelece a espessura da camada de concentração. Os resultados são apresentados com análise de convergência através de tabelas e com gráficos para o fluxo transmembrana local e médio, a correlação de Sherwood e a espessura da camada limite de concentração e ainda são comparados com outros resultados e metodologias reportadas na literatura. In this doctoral thesis, the analytical-numerical hybrid technique, internationally known as GITT (Generalized Integral Transform Technique), is used for the modeling and simulation of the equation of chemical species conservation, in the investigation of the incompressible, Newtonian and permanent laminar flow in permeable tubes. The flow is applied to the cross-flow process with membranes and two studies related to the elliptic and parabolic convective-diffusive equation were accomplished, for which the same boundary conditions are used. In the modeling, the velocity on the permeable wall is considered uniform and the velocity profiles for the entrance region flow are obtained from the literature. The mathematical model originally uses an expression for the concentration boundary layer thickness, with a methodology that determines the asymptotic ratio, establishing the concentration boundary layer thickness. The results are presented with convergence analysis through tables and with graphs for the mean local transmembrane flux, Sherwood correlation and the concentration boundary layer thickness, and they are also compared with other results and methodologies reported in the literature.

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Hellon, C. S. "On the use of the boundary layer integral equations for the prediction of skin friction and heat transfer." Thesis, Cranfield University, 1986. http://hdl.handle.net/1826/3616.

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The usefulness of the energy equation integrated over the thickness of the boundary layer, in predicing heat transfer rates to smooth body surfaces in investigated. It is found that on assuming very simple closure relations, similar to those often used with the momentum equation, highly accurate predictions are made. It is shown further that the usefulness of these predictions extend into areas where the momentum equation-skin friction predictions, which have proved so popular, break down such as regions of reverse flow and shock/boundary layer interactions. The technique is has been tested in laminar transitional and turbulent flows with both experiment and other more complex theories. The technique is extended to three-dimensional laminar flows with the inclusion of a crossflow model.

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Rogozhin, Alexander. "Approximation methods for two classes of singular integral equations." Doctoral thesis, [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=968783279.

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R?go, Maria das Gra?as Oliveira. "An?lise da magnetohidrodin?mica com transfer?ncia de calor em canais de placas paralelas via transforma??o integral." Universidade Federal do Rio Grande do Norte, 2010. http://repositorio.ufrn.br:8080/jspui/handle/123456789/15631.

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Made available in DSpace on 2014-12-17T14:58:04Z (GMT). No. of bitstreams: 1 MariaGOR_DISSERT.pdf: 1839301 bytes, checksum: 7f08c7ee57fc0bc1f8282eb165223c37 (MD5) Previous issue date: 2010-11-12 Universidade Federal do Rio Grande do Norte The main goal of the present work is related to the dynamics of the steady state, incompressible, laminar flow with heat transfer, of an electrically conducting and Newtonian fluid inside a flat parallel-plate channel under the action of an external and uniform magnetic field. For solution of the governing equations, written in the parabolic boundary layer and stream-function formulation, it was employed the hybrid, numericalanalytical, approach known as Generalized Integral Transform Technique (GITT). The flow is sustained by a pressure gradient and the magnetic field is applied in the direction normal to the flow and is assumed that normal magnetic field is kept uniform, remaining larger than any other fields generated in other directions. In order to evaluate the influence of the applied magnetic field on both entrance regions, thermal and hydrodynamic, for this forced convection problem, as well as for validating purposes of the adopted solution methodology, two kinds of channel entry conditions for the velocity field were used: an uniform and an non-MHD parabolic profile. On the other hand, for the thermal problem only an uniform temperature profile at the channel inlet was employed as boundary condition. Along the channel wall, plates are maintained at constant temperature, either equal to or different from each other. Results for the velocity and temperature fields as well as for the main related potentials are produced and compared, for validation purposes, to results reported on literature as function of the main dimensionless governing parameters as Reynolds and Hartman numbers, for typical situations. Finally, in order to illustrate the consistency of the integral transform method, convergence analyses are also effectuated and presented O prop?sito do estudo desenvolvido nesse trabalho est? relacionado com a din?mica do escoamento incompress?vel, laminar, em regime permanente, com transfer?ncia de calor, de um fluido newtoniano condutor el?trico, no interior de um canal de placas planas paralelas, submetido a um campo magn?tico externo uniforme. Para a solu??o das equa??es de governo, modeladas atrav?s da formula??o parab?lica de camada limite em fun??o corrente, foi empregado o m?todo h?brido, num?rico-anal?tico, conhecido como T?cnica da Transformada Integral Generalizada (GITT). O escoamento analisado ? sustentando por um gradiente de press?o e assume-se que o campo magn?tico externo, aplicado na dire??o normal ao escoamento, permanece uniforme, muito maior do que quaisquer outros campos gerados em outras dire??es, n?o sendo, dessa forma, influenciado por nenhum efeito magn?tico interno. Para avaliar a influ?ncia do campo magn?tico sobre o desenvolvimento t?rmico e hidrodin?mico desse problema de convec??o for?ada, e tamb?m para fins de valida??o da metodologia de solu??o adotada, foram empregados dois tipos de condi??es de contorno para o campo de velocidade na entrada no canal: perfil uniforme e perfil parab?lico do escoamento sem campo magn?tico completamente desenvolvido. Para o problema t?rmico, por outro lado, empregou-se apenas o perfil uniforme de temperatura na entrada do canal e considerou-se que as placas se mant?m ? temperatura constante, iguais ou diferentes uma da outra. Resultados para os campos de velocidade, temperatura e potenciais correlatos s?o produzidos e comparados aos da literatura em fun??o dos principais par?metros de governo, a saber, n?mero de Reynolds, n?mero de Hartmann e par?metro el?trico, para algumas situa??es t?picas. Com o objetivo de ilustrar a consist?ncia da t?cnica da transformada integral generalizada, an?lises de converg?ncia s?o tamb?m efetuadas e apresentadas

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Lambert, Alex. "Learning function-valued functions in reproducible kernel Hilbert spaces with integral losses : Application to infinite task learning." Electronic Thesis or Diss., Institut polytechnique de Paris, 2021. http://www.theses.fr/2021IPPAT016.

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Les méthodes à noyaux sont au coeur de l'apprentissage statistique. Elles permettent de modéliser des fonctions à valeurs réelles dans des espaces de fonctions à fort potentiel représentatif, sur lesquels la minimisation de risques empiriques régularisés est possible et produit des estimateurs dont le comportement statistique est largement étudié. Lorsque les sorties ne sont plus réelles mais de plus grande dimension, les Espaces de Hilbert à Noyaux Reproduisants à valeurs vectorielles (vv-RKHSs) basés sur des Noyaux à Valeurs Opérateurs (OVKs) fournissent des espaces de fonctions similaires et permettent de traiter des problèmes tels que l'apprentissage multi-tâche, la prédiction structurée ou la régression à valeurs fonctionnelles. Dans cette thèse, nous introduisons une extension fonctionnelle originale du cadre multi-tâche appelée Apprentissage d'un Continuum de Tâches (ITL), qui permet de résoudre conjointement un continuum de tâches paramétrées, parmi lesquelles la régression quantile, la classification à coût assymétrique, ou l'estimation de niveaux de densité. Nous proposons un cadre d'apprentissage basé sur des fonctions de pertes intégrales qui comprend à la fois l'ITL et la régression à valeurs fonctionnelles, ainsi que des méthodes d'optimisation pour résoudre les problèmes de minimisation de risque empirique régularisé résultants. Par un échantillonage des pertes intégrales, nous obtenons une représentation de dimension finie des solutions pour différents choix de régularisation ou pénalités liées à la forme des fonctions, tout en gardant un contrôle théorique sur les capacités en généralisation des estimateurs. L'usage de la dualité lagrangienne vient approfondir ces méthodes, en apportant en particulier les moyens d'imposer des estimateurs parcimonieux ou robustes à l'aide de pertes convoluées. Les problèmes de passages à l'échelle sont traités par l'utilisation noyaux approchés, dont les vv-RKHSs associés sont de dimension finie. Nous proposons aussi une architecture composée d'un réseau de neurone et d'une dernière couche à noyaux, qui permet l'apprentissage de représentations appropriées aux noyaux utiles dans les applications avec des données complexes comme les images. Ces techniques sont appliquées à plusieurs problèmes d'ITL, ainsi qu'au problème de régression fonction-à-fonction robuste en présence de valeurs aberrantes. Enfin, nous revisitons les problemes de transfert de style sous l'angle ITL, avec une application au transfert d'émotion Kernel methods are regarded as a cornerstone of machine learning.They allow to model real-valued functions in expressive functional spaces, over which regularized empirical risk minimization problems are amenable to optimization and yield estimators whose statistical behavior is well studied. When the outputs are not reals but higher dimensional, vector-valued Reproducible Kernel Hilbert Spaces (vv-RKHSs) based on Operator-Valued Kernels (OVKs) provide similarly powerful spaces of functions, and have proven useful to tackle problems such as multi-task learning, structured prediction, or function-valued regression.In this thesis, we introduce an original functional extension of multi-output learning called Infinite Task Learning (ITL), that allows to jointly solve an infinite number of parameterized tasks, including for instance quantile regression, cost-sensitive classification and density level set estimation.We propose a learning framework based on convex integral losses that encompasses the ITL problem and function-valued regression. Optimization schemes dedicated to solving the associated regularized empirical risk minimization problems are designed. By sampling the integral losses, we derive finite-dimensional representation of the solution under several choices of regularizers or shape constraints penalties, while keeping theoretical guarantees over their generalization capabilities. We also employ dualization techniques with the benefit of bringing desirable properties such as robustness or sparsity to the estimators thanks to the use of convoluted losses. Scalability issues are addressed by deriving optimization algorithms in the the context of approximated OVKs whose corresponding vv-RKHSs are of finite dimension. The use of trainable deep architectures composed by a neural network followed by a shallow kernel layer is also investigated as a way to learn the kernel used in practice on complex data such as images.We apply these techniques to various ITL problems and to robust function-to-function regression, that are tackled in the presence of outliers. We also cast style transfer problems as a vectorial output ITL problem and demonstrate its efficiency in emotion transfer

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Meszmer, Peter. "Hierarchische Integration und der Strahlungstransport in streuenden Medien." Doctoral thesis, Universitätsbibliothek Leipzig, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-98584.

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Der Strahlungstransport stellt eine von drei Arten des Wärmetransports zwischen Gebieten unterschiedlicher Temperatur dar. Eine der einfachsten Formen bildet der Strahlungstransport im Vakuum, ein Vorgang, der im kosmischen Umfeld, beispielsweise bei der Energieübertragung von einem Stern auf seine Planeten, beobachtbar ist. Hierbei ist es hinreichend, sich auf die Betrachtung von Oberflächen zu beschränken. Strahlungstransport kann jedoch auch in semitransparenten Medien, wie biologischem Gewebe oder Glas, beobachtet werden. Das Medium, in dem der Strahlungstransport erfolgt, wirkt sich durch Vorgänge wie Absorption, Emission, Reflexion oder Streuung auf den Strahlungstransport aus. Für die Modellierung des Strahlungstransports in einem solchen Umfeld können verschiedene Modelle, darunter das Strahlenmodell, genutzt werden. Dieses Modell beschreibt den Wärmetransport anhand einer skalaren Größe, die Strahlungsintensität genannt wird. Betrachtet wird die Strahlungsintensität in diesem Modell entlang eines Strahls in eine vorgegebene Richtung. Die mathematische Darstellung des Strahlenmodells des Strahlungstransports in partizipierenden Medien führt auf eine richtungsabhängige Integro-Differentialgleichung. Ist die Richtungsabhängigkeit nicht von Interesse, so kann der Übergang zu einer winkelintegrierten Form erfolgen. Dieser Übergang führt schließlich auf ein System schwach singulärer fredholmscher Integralgleichungen zweiter Art. Dieses charakterisiert nun nicht mehr die erwähnte Strahlungsintensität, sondern beschreibt die sogenannte Einstrahlung sowie den Strahlungsfluss. Das System singulärer Integralgleichungen kann mittels eines Galerkin-Ansatzes numerisch gelöst werden. Geht man von einer hinreichenden Glattheit des Randes aus, kann die Kompaktheit des Operators der Integralgleichungen gezeigt werden. Dies wiederum erlaubt Rückschlüsse auf die Existenz und Eindeutigkeit einer Lösung. Ein Augenmerk bei der Ermittlung der Galerkin-Näherung ist auf die Bestimmung der singulären Integrale der Galerkin-Diskretisierung zu richten. Für die Bestimmung multidimensionaler, singulärer Integrale stellt die Arbeit das Verfahren der hierarchischen Integration vor. Basierend auf einer Zerlegung des Integrationsgebietes, erfolgt die Beschreibung singulärer Integrale durch ein Gleichungssystem, dessen rechte Seite nur von regulären Integralen abhängig ist. Können diese regulären Integrale sowie die Lösung des Gleichungssystems exakt bestimmt werden, so sind auch die singulären Integrale exakt bestimmt. Bei einer numerischen Bestimmung der regulären Integrale ist die Fehlerordnung ausschlaggebend für den Fehler der singulären Integrale. Als Integrationsgebiete werden Hyperwürfel beliebiger Dimension sowie Simplizes bis einschließlich Dimension 3 als Integrationsgebiete betrachtet. Als Voraussetzungen an den Kern des Doppelintegrals sind nur die Eigenschaften der Translationsinvarianz sowie der Homogenität zu richten. Kann ein nicht translationsinvarianter oder nicht homogener Kern eines Integrals in Summanden zerlegt werden, die selbst translationsinvariant und homogen sind, ist auch die Bestimmung solcher Integrale möglich. Darüber hinaus stellt die Arbeit Verbindungen zu dem Begriff des Hadamard partie finie her. Auf diese Weise lässt sich das Verfahren der hierarchischen Integration für beliebige Dimensionen und beliebige Singularitätsordnungen anwenden. Die Strahlungstransportgleichung ist im Allgemeinen mittels eines Galerkin-Ansatzes lösbar, führt jedoch auf eine voll besetzte Systemmatrix. Numerische Beispiele beleuchten daher Methoden der Matrixkompression mittels hierarchischer Matrizen sowie der direkten Erzeugung schwach besetzter Matrizen über regulären Gittern und Gittern mit hängenden Knoten und skizziert Ansätze zur Parallelisierung auf entsprechenden Computersystemen.

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Lee, Kuan-Lin. "Development of a Compact Thermal Management System Utilizing an Integral Variable Conductance Planar Heat Pipe Radiator for Space Applications." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1484168448272184.

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Silva, Bruno Nunes Melo da. "Aplica??o da t?cnica da transformada integral generalizada em escoamentos em canais considerando efeitos magnetohidrodin?micos." Universidade Federal do Rio Grande do Norte, 2014. http://repositorio.ufrn.br/handle/123456789/19291.

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Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2015-10-14T20:45:55Z No. of bitstreams: 1 BrunoNunesMeloDaSilva_DISSERT.pdf: 3354700 bytes, checksum: 03b0257506443078469f4a0082749a27 (MD5) Approved for entry into archive by Elisangela Moura (lilaalves@gmail.com) on 2015-10-14T21:47:15Z (GMT) No. of bitstreams: 1 BrunoNunesMeloDaSilva_DISSERT.pdf: 3354700 bytes, checksum: 03b0257506443078469f4a0082749a27 (MD5) Made available in DSpace on 2015-10-14T21:47:15Z (GMT). No. of bitstreams: 1 BrunoNunesMeloDaSilva_DISSERT.pdf: 3354700 bytes, checksum: 03b0257506443078469f4a0082749a27 (MD5) Previous issue date: 2014-05-02 O prop?sito de solu??es h?bridas, atrav?s da aplica??o da T?cnica da Transformada Integral Generalizada (GITT), permite o desenvolvimento para o tratamento do problema de escoamento com transfer?ncia de calor transiente para fluidos newtonianos condutores el?tricos submetidos a campos magn?ticos constantes em um canal de placas planas e paralelas com ou sem rota??o do canal, matematicamente esse problema ? modelado por sistemas de equa??es diferencias acopladas. No escoamento, as influ?ncias de efeitos Hall, deslizamento de ?ons e presen?a de part?culas s?lidas no escoamento s?o consideradas. O escoamento transiente ? mantido por gradiente de press?o constante ou exponencial, em regime permanente ? considerado o movimento da placa superior bem como a advec??o pelos poros da placa. O campo magn?tico ? aplicado na dire??o normal ao escoamento. Assume-se que tal campo magn?tico ? constante e n?o ? afetado pelo escoamento, de maneira que apenas a intera??o de uma via entre o escoamento do fluido condutor el?trico e o campo magn?tico ? estudada. Admite-se, no escoamento, a varia??o das propriedades f?sicas transportadas, tais como, viscosidade, condutividade t?rmica e el?trica com a temperatura. Resultados s?o obtidos e comparados com outros resultados num?ricos para os campos de velocidade e temperatura do fluido e das part?culas s?lidas em fun??o dos par?metros governantes, a saber, n?mero de Reynolds, Hartmann, hall, deslizamento de ?ons, concentra??o das part?culas s?lidas e par?metros f?sicos. Nas solu??es num?ricas, obtidas com o uso das bibliotecas do IMSL? e Fortran utiliza-se precis?o prescrita e trunca-se, a uma ordem finita, o sistema ordin?rio transformado o qual ? resolvido numericamente com uso das sub-rotinas bem estabelecidas no IMSL?. ? realizada an?lise de converg?ncia para os principais potenciais com o objetivo de ilustrar a consist?ncia da t?cnica (GITT) e a sua utiliza??o com finalidades de benchmark nessa ?rea da din?mica dos fluidos e transfer?ncia de calor. The present study proposes the development of hybrid solutions to the transient Hartmann flow problem with heat transfer of an electrically conducting and newtonian fluid subjected to a constant magnetic field. The Generalized Integral Transform Technique is employed to analyze the influence of Hall and ion-slip effects, as well as the presence of solid particles on flow behavior, which is maintained by a constant or exponential-decaying gradient pressure. A transverse flow normal to the walls can also occurs, so that plates can be both porous. Additionally, a movement of the upper plate in the longitudinal direction can be considered. Here, it is assumed that the magnetic field is constant, being not affected by the flow, so that only an one-way interaction between the flow and the magnetic field is studied. Temperature-dependent transport properties, such as viscosity, thermal and electrical conductivity, can be considered too. Hybrid results are obtained and compared to other numerical results for the velocity and temperature fields of flow and solid particles as function of the main dimensionless governing parameters, namely, Reynolds number, Hartmann number, Hall, Ion-slip and concentration of solid particles. Convergence analyses are carried out for the main potentials in order to illustrate the consistency of the technique (GITT) and its use for purposes of benchmarking in the area of heat and fluid flow.

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18

Goomanee, Salvish. "Rigorous Approach to Quantum Integrable Models at Finite Temperature." Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEN039/document.

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Cette thèse développe un cadre rigoureux qui permet de démontrer des représentations exactes associées à divers observables de la chaîne XXZ de Heisenberg de spin 1/2 à température finie. Il a était argumenté dans la littérature que l’énergie libre par site ou les longueurs de corrélations admettent des représentations intégrales où les intégrandes sont exprimées en termes de solutions d’équations intégrales non-linéaires. Les dérivations de ces représentations reposaient sur divers conjectures telles que l’existence d’une valeur propre de la matrice de transfert quantique, real, non-dégénérée, de module maximale, de l’échangeabilitée de la limite du volume infinie et du nombre de Trotter à l’infinie, de l’existence et de l’unicité des solutions des equation intégrales non-linéaires auxiliaires et finalement de l’identification des valeurs propers de la matrice de transfert quantiques avec les solutions de l’équations intégrales non-linéaires. Nous démontrons toutes ces conjectures dans le regime de haute température. Nôtre analyse nous permet aussi de démontrer que pour ces température suffisamment élevées, il est possible d’avoir une description d’un certain sous-ensemble de valeurs propres sous-dominante de la matrice de transfert quantique décrite en terme de solutions d’une chaîne de spin-1 de taille finie This thesis develops a rigorous framework allowing one to prove the exact representations for various observables in the XXZ Heisenberg spin-1/2 chain at finite temperature. Previously it has been argued in the literature that the per-site free energy or the correlation lengths admit integral representations whose integrands are expressed in terms of solutions of non-linear integral equations. The derivations of such representations relied on various conjectures such as the existence of a real, non-degenerate, maximal in modulus Eigenvalue of the quantum transfer matrix, the exchangeability of the infinite volume limit and the Trotter number limits, the existence and uniqueness of the solutions to the auxiliary non-linear integral equations and finally the identification of the quantum transfer matrix’s Eigenvalues with solutions to the non-linear integral equation. We rigorously prove all these conjectures in the high temperature regime. Our analysis also allows us to prove that for temperatures high enough, one may describe a certain subset of sub-dominant Eigenvalues of the quantum transfer matrix described in terms of solutions to a spin-1 chain of finite length

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Mahiddini, Florian. "Modélisation couplée Compatibilité Électromagnétique - Thermique d’architectures de câblages électriques embarquées." Thesis, Toulouse, ISAE, 2018. http://www.theses.fr/2018ESAE0007/document.

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Le développement d’aéronefs « plus » voire « tout » électriques a pour conséquence la conception d’architectures électriques embarquées de plus en plus complexes entraînant une très nette augmentation du nombre de câbles électriques à déployer au sein des véhicules. Parmi les contraintes rencontrées lors des phases de définition et d’intégration des réseaux de câblages, les aspects de compatibilité électromagnétique et de gestion des échauffements thermiques deviennent de plus en plus critiques. Ainsi, ces travaux de thèse sont dédiés au développement d’une méthodologie permettant la prédiction d’une part, des courants induits par et sur les réseaux de câblages et d’autre part, de leur niveaux d’échauffement. En particulier, l’analyse bibliographique effectuée à cette occasion montre que les phénomènes électrostatiques (à la base de la théorie des lignes de transmission) et de conduction stationnaire de la chaleur sont strictement analogues, ce qui autorise une résolution simultanée de ces deux problèmes pour les réseaux de câblages considérés. Les présents travaux démontrent que le calcul des paramètres électriques primaires (p.u.l) du réseau et de la distribution de température dans le plan transverse peut se faire de manière totalement couplé à l’aide d’un schéma numérique basé sur la Méthode des Moments(MoM). Le choix de l’utilisation des équations intégrales pour la résolution de ce problème de potentiel se fonde sur plusieurs avantages tels qu’une utilisation optimisée des ressources de calcul et l’utilisation d’algorithmes efficaces de résolution, de surcroît naturellement parallélisables pour de futurs développements. Les outils de calculs thermiques développés dans le cadre de cette thèse, et qui ont vocation à être intégrés dans la suite logicielle CRIPTE de l’ONERA, ont fait l’objet d’une validation expérimentale pour plusieurs configurations de harnais électriques. Les comparaisons simulations-mesures présentent de bons accords bien que les expérimentations menées aient montré la difficulté d’obtenir précisément des valeurs du coefficient d’échange thermique,même dans des conditions parfaitement maîtrisées. Les travaux ouvrent enfin des perspectives nouvelles sur l’optimisation en terme de masse des réseaux de câblage (EWIS) The on-going development of “more” or “all” electrical aircraft leads to the design of ever-complex embeddedelectrical networks, which causes a significant increase of electrical cables to be used within these innovativevehicles. Among the constraints encountered during the definition and integration phases of the network, thoserelated to the electromagnetic compatibility between equipment as well as the management of thermal heatingby Joule’s effect become more and more stringent. Thus, this thesis is dedicated to the development of anoriginal methodology enabling the prediction of both induced and crosstalk currents as well as the heating upstate in complex bundles of cables. Indeed, literature review explicitly shows that electrostatic and stationaryheat transfer phenomena are, from a mathematical standpoint, strictly the same which allows the simultaneouscomputation of these two problems for an arbitrary network. This research work demonstrates that the determinationof primary electrical parameters (per unit length) and the temperature distribution within a givencross-section can be handled with the numerical Method Of Moment (MoM). This choice is motivated by theseveral inherent advantages of the method like an optimized use of the computer resource and the naturalparallelization of the algorithms. The developed numerical tools, intended to be fully integrated in the in-housesoftware suite CRIPTE, has been validated during an experimental campaign that has involved several typesof bundles. Although the comparisons between experimental and simulated results comply with each other,experiments reveal the hard task of getting a precise estimation of the heat transfer coefficients, even in awell-controlled environment. Finally, these works open new and very promising perspectives for future EWIS(Electrical Wiring Interconnection System) in term of mass optimization

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20

Li, Xiaochun. "Uniform bounds for the bilinear Hilbert transforms /." free to MU campus, to others for purchase, 2001. http://wwwlib.umi.com/cr/mo/fullcit?p3025634.

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21

Chunaev, Petr. "Singular integral operators and rectifiability." Doctoral thesis, Universitat Autònoma de Barcelona, 2018. http://hdl.handle.net/10803/663827.

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Los problemas que estudiamos en esta tesis se encuentran en el área de Análisis Armónico y Teoría de la Medida Geométrica. En particular, consideramos la conexión entre las propiedades analíticas de operadores integrales singulares definidos en $L^2(\mu)$ y asociados con algunos núcleos de Calderón-Zygmund y las propiedades geométricas de la medida $\mu$. Seamos más precisos. Sea $E$ un conjunto de Borel en el plano complejo con la medida lineal de Hausdorff $H^1$ finita y distinta de cero, es decir, $0<H^1(E)<\infty $. G. David y J.C. Léger (1999) probaron que el núcleo de Cauchy $1/z$ (e su parte real $(\Re z)/|z|^2$ también) tiene la siguiente propiedad: la $L^2(H^1_E)$-acotación de los operadores integrales singulares correspondientes implica que $E$ es rectificable. Más tarde, V. Chousionis, J. Mateu, L. Prat y X. Tolsa (2012) probaron la misma propiedad para el núcleo $(\ Re z)^3/|z|^4$. Además, hay ejemplos de los núcleos debidos a P. Huovinen (2001) y B. Jaye y F. Nazarov (2013) tales que los operadores integrales singulares correspondientes son $L^2(H^1_E)$-acotados por algunos conjuntos $E$ puramente no rectificables, es decir, la propiedad mencionada anteriormente no se cumple. En la tesis, presentamos nuestros resultados relacionados con el comportamiento de operadores integrales singulares asociados con la clase de núcleos de Calderón-Zygmund $ (\Re z)^3/|z|^4 + t \cdot (\Re z)/|z|^2$, donde $t$ es un parámetro real. Se muestra que esta clase de núcleos generaliza todos los mencionados anteriormente considerados por diferentes autores. Además, probamos que la propiedad “$L^2$-acotación implica rectificabilidad” se cumple para los operadores con $t\in(-\infty,-\sqrt{2})\cup(-t_0,+\infty]$, donde $t_0>0$ es una pequeña constante absoluta. Es importante que, para algunos de los $t$ que acabamos de mencionar, el llamado método de curvatura comúnmente utilizado para relacionar $L^2$-acotación y rectificabilidad no está disponible, pero todavía es posible establecer la propiedad mencionada. Hasta donde sabemos, es el primer ejemplo de este tipo en el plano complejo. También vale la pena mencionar que ampliamos nuestros resultados a una clase aún más general de núcleos y, además, consideramos problemas análogos para conjuntos $E$ Ahlfors-David-regulares. The problems that we study in this thesis lie in the area of Harmonic Analysis and Geometric Measure Theory. Namely, we consider the connection between the analytic properties of singular integral operators defined in $L^2(\mu)$ and associated with some Calderón-Zygmund kernels and the geometric properties of the measure $\mu$. Let us be more precise. Let $E$ be a Borel set in the complex plane with non-vanishing and finite linear Hausdorff measure $H^1$, i.e. such that $0<H^1(E)<\infty$. G. David and J.C. Léger (1999) proved that the Cauchy kernel $1/z$ (and even its real part $(\Re z)/|z|^2$) has the following property: the $L^2(H^1_E)$-boundedness of the corresponding singular integral operators implies that $E$ is rectifiable. Later on, V. Chousionis, J. Mateu, L. Prat and X. Tolsa (2012) proved the same property for the kernel $(\Re z)^3/|z|^4$. Moreover, there are examples of kernels due to P. Huovinen (2001) and B. Jaye and F. Nazarov (2013) such that the corresponding singular integral operators are $L^2(H^1_E)$-bounded for some purely unrectifiable sets $E$, i.e. the above-mentioned property does not hold. In the thesis, we present our results related to the behaviour of singular integral operators associated with the class of Calderón-Zygmund kernels $(\Re z)^3/|z|^4+t\cdot (\Re z)/|z|^2$, where $t$ is a real parameter. It is shown that this class of kernels generalizes all above-mentioned ones considered by different authors. Furthermore, we prove that the property “$L^2$-boundedness implies rectifiability” holds for the operators with $t\in (-\infty,-\sqrt{2}) \cup (-t_0,+\infty]$, where $t_0>0$ is a small absolute constant. It is important that for some of the $t$ just mentioned the so called curvature method commonly used to relate $L^2$-boundedness and rectifiability is not available but it is still possible to establish the above-mentioned property. To the best of our knowledge, it is the first example of this type in the plane. It is also worth mentioning that we extend our results to even more general class of kernels and additionally consider analogous problems for Ahlfors-David regular sets $E$.

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Terrée, Guillaume. "Méthode de Monte-Carlo et non-linéarités : de la physique du transfert radiatif à la cinétique des gaz." Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2015. http://www.theses.fr/2015EMAC0017/document.

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En physique du transport, en particulier en physique du transfert radiatif, la méthode de Monte-Carlo a été développée à l'origine comme la simulation de l'histoire d'un grand nombre de particules, dont on déduit des observables moyennes. Cette méthode numérique doit son succès à plusieurs qualités : une gestion naturelle des espaces des phases aux nombreuses dimensions, une erreur systématique nulle par rapport au modèle physico-mathématique, les intervalles de confiance donnés avec les résultats, une capacité à prendre en compte simultanément de nombreux phénomènes physiques, la possibilité de calcul de sensibilités simultané, et une parallélisation aisée. En cinétique des gaz, les particules collisionnent entre elles et non pas avec un milieu extérieur ; on dit que leur transport est non-linéaire. Ces collisions mutuelles mettent en défaut l'approche évoquée ci-dessus de la méthode de Monte-Carlo ; car pour simuler des trajectoires indépendantes de multiples particules et ainsi estimer leur distribution, il faut connaître au préalable exactement cette même distribution...Cette thèse fait suite à celles de Jérémi DAUCHET (2012) et de Mathieu GALTIER (2014), consacrées au transfert radiatif. Entre autres travaux, ces auteurs montraient comment la méthode de Monte-Carlo peut s'accommoder de non-linéarités, en gardant son formalisme et ses spécificités habituelles. Les non-linéarités alors franchies étaient respectivement une loi de couplage chimie/luminance, et la dépendance de la luminance envers le coefficient d'absorption. On essaie dans ce manuscrit d'outrepasser la non-linéarité du transport. Pour cela, nos principaux outils sont un suivi des particules en remontant le temps, basé sur des formulations intégrales des équations de transport, formulations largement inspirées des algorithmes dits à collisions nulles. Nous montrons, sur plusieurs exemples académiques, que nous avons en effet étendu la méthode de Monte-Carlo à la résolution de l'équation de Boltzmann. Ces exemples sont aussi l'occasion de tester les limites de ce que nous avons mis en place. Les résultats les plus marquants sont certainement l'absence totale de maillage dans la méthode numérique, ainsi que sa capacité à calculer correctement les quantités de particules de haute énergie cinétique (toujours peu nombreuses par rapport au total, en cinétique des gaz). Au-delà des exemples fournis, ce manuscrit est voulu comme un essai de formalisme et une exploration des bases de la méthode développée. L'accent est mis sur les raisonnements menant à la mise au point de la méthode, plutôt que sur les implémentations particulières qui ont été abouties. La méthode est encore, aux yeux de l'auteur, largement susceptible d'être retravaillée. En particulier, les temps maximaux sur lesquels l'évolution des particules est calculable, qui constituent la faiblesse principale de la méthode numérique développée, peuvent sûrement être augmentés In transport physics, especially in radiative transfer physics, the Monte-Carlo method has been originally developed as the simulation of the history of numerous particles, from which are deduced mean observables. This numerical method owes its success to several qualities : a natural management of many-dimensional phase space, a null systematic error away from the mathematical and physical model, the confidence intervals given with the results, an ability to take into account simultaneously numerous physical phenomenons, the simultaneous sensitivities calculating possibility, and an easy parallelization. In gas kinetics, particles collide each other, not with an external fixed medium ; it is said that their transport is non-linear. These mutual collisions put out of action the aforesaid approach of the Monte-Carlo method ; because in order to simulate the independent trajectories of multiple particles and thus estimate their distribution, this distribution must beforehand be exactly known...This thesis follows on from those of Jérémy DAUCHET (2012) and of Mathieu GALTIER (2014), dedicated to radiative transfer physics. Between other works, these authors have shown how the Monte-Carlo method can bear non-linearities, while keeping its customary formalism and specificities. The then overcome non-linearities were respectively a chemistry/irradiance coupling law, and the dependence of the irradiance toward the absorption coefficient. We try in this manuscript to overcome the non-linearity of the transport. In this aim, our main tools are a reverse following of particles, based on integral formulations of the transport equations, formulations largely inspired from the so-called null collisions algorithms. We show, on several academic examples, that we have indeed extended the Monte Carlo method to the resolution of the Boltzmann equation. These examples are also occasions to test the limits of what we have built. The most noteworthy results are certainly the absence of any mesh in the numerical method, and its capacity to calculate correctly the high-speed particles quantities (always rare compared to the total, in gas kinetics). Beyond the given examples, this manuscript is wanted as a formalism attempt and an exploration of the developed method basics. The focus is made on the reasoning leading to the method, rather than on particular implementations which have been realized. In the eyes of the author, the method is still largely reworkable. In particular, the maximal times on which the evolution of particles is computable, which constitute the main weakness of the developed numerical method, can surely be increased

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Gomes, Francisco Augusto Aparecido [UNESP]. "Estudo analítico/numérico do problema de ablação em corpos rombudos com simetria axial." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/88887.

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Made available in DSpace on 2014-06-11T19:23:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-04-24Bitstream added on 2014-06-13T19:50:37Z : No. of bitstreams: 1 gomes_faa_me_ilha.pdf: 1304340 bytes, checksum: 93a9b85b39e238ee85d2a3ae10503b07 (MD5) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) O fenômeno da ablação é um processo que envolve o estudo de proteções térmicas, com muitas aplicações, principalmente na engenharia mecânica e aeroespacial. O processo envolve transferência de calor com movimento de fronteira, onde a posição é desconhecida a priori. As equações governantes do processo formam um sistema não-linear de equações diferenciais acoplado. A análise unidimensional do processo ablativo é realizada em um corpo de revolução, o qual está sobre intenso aquecimento. Esse problema é resolvido utilizando a Técnica da Transformada Integral Generalizada – TTIG, para solução do sistema de equações governantes. Como condição de contorno é considerada um fluxo de calor transiente no contorno, como por exemplo, o que ocorre com veículos na reentrada da atmosfera. A teoria do fluxo de calor de Tauber e de Van Driest é utilizada nessa análise. Os resultados de interesse são, a espessura e a taxa de material ablatado. Os resultados obtidos são comparados com resultados disponíveis de outras técnicas de solução em literaturas. The phenomenon of ablation is a process of thermal protection with several applications, mainly, in mechanical and aerospace engineering. This process involves heat transfer with a moving boundary which position is unknown a priori. The governing equations of the process are a non-linear system of coupled partial differential equations. The onedimensional analysis of ablative process has been done in a revolution body, which is on intense heating. This problem is performed by using the generalized integral transform technique – GITT for solution of the system of governing equations. As boundary condition is considered a transient heat flux like ones that occur, for example, in re-entrance of aerospace vehicles in the atmosphere. The heat flux theory of Tauber and Van Driest were used in that analysis. The results of interest are the thickness and the rate of loss of the ablative material. The obtained results are compared with available results of other techniques of solution in the literature.

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Souza, Luís Henrique Gazeta de [UNESP]. "Aplicação da transformada integral generalizada no escoamento potencial em contrações." Universidade Estadual Paulista (UNESP), 2009. http://hdl.handle.net/11449/88871.

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Made available in DSpace on 2014-06-11T19:23:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-07-30Bitstream added on 2014-06-13T20:50:44Z : No. of bitstreams: 1 souza_lhg_me_ilha.pdf: 1993240 bytes, checksum: b09e517d41877144e2a7b2634fd5fd55 (MD5) Realiza-se a formulação matemática do escoamento potencial no interior de contrações bidimensionais usando sistemas de coordenadas cartesianas e cilíndricas. Para tal considera-se que as geometrias das contrações sejam bidimensionais no sistema de coordenadas cartesianas e bidimensionais com simetria axial no sistema de coordenadas cilíndricas. A formulação é adaptada a partir das equações tridimensionais de Euler em coordenadas cartesianas e cilíndricas, fazendo-se as hipóteses de bidimensionalidade, regime permanente, fluido invíscido e escoamento irrotacional. O formalismo diferencial do escoamento potencial no interior de contrações bidimensionais é formalmente resolvido utilizando-se a Técnica da Transformada Integral Generalizada – TTIG – cuja fundamentação está na expansão de funções-quadrado-integráveis em séries de funções ortogonais. Desenvolveu-se algoritmos computacionais, em linguagem computacional Fortran 95, para simular as soluções formais obtidas e produzir resultados numéricos que possibilitassem a análise do escoamento potencial nas referidas contrações. Realizou-se extensivos testes numéricos para quatro famílias de geometrias das contrações, sendo que cada família ainda possuía diferentes funções modeladoras do formato de suas paredes, bem como os parâmetros razão e esbeltez e razão de contração. Analisou-se os resultados visando sintetizar aspectos e características de como as contrações operam e que formatos são mais adequados ou não It was done the mathematical formulation for potential flow inside two-dimensional contractions using both Cartesian and cylindrical coordinate systems. To achieve such aim it was considered that contraction geometries are two-dimensional in the Cartesian coordinate system and two-dimensional with axial symmetry in cylindrical system. Formulation is adapted from tri-dimensional Euler equations in Cartesian and cylindrical coordinate systems, doing hypothesis such as: two-dimensionality, steady flow regime, inviscid fluid and irrotational flow. Differential formulae that models potential flow inside two-dimensional contraction is formally solved using Generalized Integral Transform Technique – GITT – which is based upon orthogonal series expansion of square-integrable functions. It was developed some computational algorithms, using Fortran 95 computational language, to simulate the obtained formal solutions and to produce numerical results that allows potential flow analysis for referred contractions. It was done comprehensive numerical tests for four families of contraction geometries, being that each family yet has different contraction wall modeling functions, as well length and contraction ratios. Results were analyzed aiming to synthesize aspects and characteristics of how contractions operate and which forms are more adequate or not

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25

Mouhat, Félix. "Fully quantum dynamics of protonated water clusters." Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS056/document.

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De nos jours, il n'existe encore aucune théorie capable de proposer une description précise et quantitative du transfert de proton en solution. En effet, ce problème est complexe du fait de la grande diversité des interactions existant dans l'eau liquide, à savoir: des interactions non liantes de type Van der Waals, des liaisons faiblement covalentes et des liaisons hydrogènes remarquablement fortes. Ces dernières sont d'ailleurs à l'origine des nombreuses propriétés fascinantes de l'eau à l'échelle macroscopique. À cela s'ajoutent les effets quantiques nucléaires dus à la faible masse de l'hydrogène, qui modifient profondément la nature de la surface d'énergie potentielle décrivant le transfert de proton le long de sa coordonnée de réaction. Nous proposons dans cette thèse une approche tout quantique basée sur une description quasi exacte de la fonction d'onde du système par l'utilisation de méthodes stochastiques de type Monte Carlo Quantique. Cette technique, combinée avec le formalisme des équations de Langevin et des intégrales de chemin de Feynman, permet de simuler à un niveau de précision inédit, n'importe quel système chimique en phase gaz ou en solution. Nous appliquons cette méthodologie à des agrégats d'eau neutres ou protonés pour apporter de nouveaux éclaircissements sur les phénomènes microscopiques régissant la diffusion du proton hydraté dans de tels systèmes. Il est mis en évidence que la mobilité du proton est optimale pour des températures proches des conditions ambiantes, du fait de la compétition subtile entre les effets thermiques et quantiques nucléaires There is no theory up to now able to provide an accurate and quantitative description of the proton transfer (PT) yet. Indeed, the complexity of the problem stems from the large diversity of the existing interactions in liquid water, namely: non bonding Van der Waals interactions, weakly covalent bonds and remarkably strong H-bonds. The latter ones are at the origin of the numerous fascinating properties of water at the macroscopic scale. In addition to such interactions, the nuclear quantum effects arising from the hydrogen light mass deeply modify the potential energy surface, and must be taken into account. In this thesis, we propose a fully quantum approach based on an almost exact description of the electronic wave function by means of Quantum Monte Carlo (QMC) methods. Our novel technique combines QMC with a Langevin-based Molecular Dynamics and the Feynman's path integral formalism. This allows one to perform fully quantum simulations of systems in gas or condensed phase, at an unprecedented level of accuracy,. We apply our approach to neutral or charged protonated water clusters to shed light on the microscopic phenomena driving the proton diffusion in such systems. We discovered that the proton hopping is optimal for temperatures close to ambient conditions, due to the subtle competition between thermal and nuclear quantum effects. This is highly suggestive of the importance of quantum nuclear effects to make PT processes - relevant for life - most efficient at room temperature

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MONTEIRO, CARLOS A. "Estudo sistêmico da geração de conhecimento no IPEN." reponame:Repositório Institucional do IPEN, 2016. http://repositorio.ipen.br:8080/xmlui/handle/123456789/26605.

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Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-08-25T18:15:44Z No. of bitstreams: 0 Made available in DSpace on 2016-08-25T18:15:44Z (GMT). No. of bitstreams: 0 Com o escopo de fornecer subsídios para compreender como o processo de colaboração científica ocorre e se desenvolve em uma instituição de pesquisas, particularmente o IPEN, o trabalho utilizou duas abordagens metodológicas. A primeira utilizou a técnica de análise de redes sociais (ARS) para mapear as redes de colaboração científica em P&D do IPEN. Os dados utilizados na ARS foram extraídos da base de dados digitais de publicações técnico-científicas do IPEN, com o auxílio de um programa computacional, e basearam-se em coautoria compreendendo o período de 2001 a 2010. Esses dados foram agrupados em intervalos consecutivos de dois anos gerando cinco redes bienais. Essa primeira abordagem revelou várias características estruturais relacionadas às redes de colaboração, destacando-se os autores mais proeminentes, distribuição dos componentes, densidade, boundary spanners e aspectos relacionados à distância e agrupamento para definir um estado de redes mundo pequeno (small world). A segunda utilizou o método dos mínimos quadrados parciais, uma variante da técnica de modelagem por equações estruturais, para avaliar e testar um modelo conceitual, apoiado em fatores pessoais, sociais, culturais e circunstanciais, para identificar aqueles que melhor explicam a propensão de um autor do IPEN em estabelecer vínculos de colaboração em ambientes de P&D. A partir do modelo consolidado, avaliou-se o quanto ele explica a posição estrutural que um autor ocupa na rede com base em indicadores de ARS. Nesta segunda parte, os dados foram coletados por meio de uma pesquisa de levantamento com a utilização de um questionário. Os resultados mostraram que o modelo explica aproximadamente 41% da propensão de um autor do IPEN em colaborar com outros autores e em relação à posição estrutural de um autor na rede o poder de explicação variou entre 3% e 3,6%. Outros resultados mostraram que a colaboração entre autores do IPEN tem uma correlação positiva com intensidade moderada com a produtividade, da mesma forma que, os autores mais centrais na rede tendem a ampliar a sua visibilidade. Por fim, vários outros indicadores estatísticos bibliométricos referentes à rede de colaboração em P&D do IPEN foram determinados e revelados, como, a média de autores por publicação, média de publicações por autores do IPEN, total de publicações, total de autores e não autores do IPEN, entre outros. Com isso, esse trabalho fornece uma contribuição teórica e empírica aos estudos relacionados à colaboração científica e ao processo de transferência e preservação de conhecimento, assim como, vários subsídios que contribuem para o contexto de tomada de decisão em ambientes de P&D. Tese (Doutorado em Tecnologia Nuclear) IPEN/T Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

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Liu, Haohao. "Integral points, monodromy, generic vanishing and Fourier-Mukai transform." Electronic Thesis or Diss., Sorbonne université, 2024. http://www.theses.fr/2024SORUS112.

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Cette thèse est une compilation de plusieurs résultats vaguement liés. Ils concernent la non-densité des points entiers sur les variétés algébriques, la méthode de Lawrence-Venkatesh-Sawin et la géométrie analytique complexe. Dans Chapitre 2, parallèlement au principe alternatif d'Ullmo et Yafaev sur les points rationnels des variétés de Shimura, nous montrons que la conjecture de Lang sur les points intégraux des variétés de Shimura est soit vraie, soit très fausse. Le Chapitre 3 est un complément à la comparaison des monodromies dans les travaux respectifs de Lawrence-Sawin et Krämer-Maculan. Nous prouvons qu'il existe de nombreux caractères, tels que le groupe de monodromie correspondant est normal dans le groupe tannakien générique. Le Chapitre 4 contient un théorème de l'annulation générique pour les variétés dans la classe Fujiki C. En particulier, cela s'applique aux variétés algébriques complexes propres lisses ainsi qu'aux variétés kählériennes compactes. Dans Chapitre 5, nous prouvons un analogue de la formule d'inversion de Fourier pour la transformation de Fourier-Mukai sur des tores complexes. Il corrige une inexactitude dans la littérature. En application, nous retrouvons la classification de Matsushima-Morimoto des fibrés vectoriels homogènes sur des tores complexes. Le Chapitre 6 est une transformation de Fourier-Mukai analytique sur les D-modules, dont la version algébrique a été étudiée par Laumon et Rothstein. Nous étendons leur résultat de dualité des variétés abéliennes aux tores complexes. En application, nous réprouvons le théorème de Morimoto, selon lequel sur un tore complexe, tout fibré vectoriel admettant une connexion admet une connexion intégrable This dissertation is a compilation of several loosely related results.They concern the nondensity of integral points on algebraic varieties, the Lawrence-Venkatesh-Sawin's method and complex analytic geometry.In Chapter 2, parallel to Ullmo and Yafaev's alternative principle on rational points of Shimura varieties, we show that Lang's conjecture about integral points on Shimura varieties is either true or very false.Chapter 3 is a complement to the monodromy comparison step in Lawrence-Sawin's and Krämer-Maculan's respective work. We prove that there are many characters, such that the corresponding monodromy group is normal in the generic Tannakian group.Chapter 4 contains a generic vanishing theorem for Fujiki class C. In particular, it applies to smooth proper complex algebraic varieties as well as compact Kähler manifolds. In Chapter 5, we prove an analog of the Fourier inversion formula for the Fourier-Mukai transform on complex tori. It corrects a misstatement in the literature. As an application, we recover Matsushima-Morimoto's classification of homogeneous vector bundles on complex tori.Chapter 6 is a lift of the analytic Fourier-Mukai to D-modules, whose algebraic version is studied by Laumon and Rothstein. We extend their duality result from abelian varieties to complex tori. As an application, we reprove Morimoto's theorem that on a complex torus, every vector bundle admitting a connection admits a flat connection

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Ramaseshan, Karthik. "Microlocal analysis of the doppler transform on R³ /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/5739.

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Bayeux, Charlotte. "Méthode intégrale pour la couche limite tridimensionnelle - Applications au givrage." Thesis, Toulouse, ISAE, 2017. http://www.theses.fr/2017ESAE0047/document.

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Depuis de nombreuses années, le givrage a été identifié comme un danger dans le domaine de l’aéronautique.L’accrétion de givre se produit lorsque des gouttelettes d’eau surfondue se déposent sur une surface, enparticulier le bord d’attaque d’une aile ou la lèvre d’entrée d’air moteur, et gèlent après l’impact. Ceci peutensuite engendrer une dégradation des performances aérodynamiques, un dysfonctionnement des sondes ouencore un endommagement du moteur. C’est pourquoi cette problématique est étudiée avec attention. Lesessais en vol et en soufflerie étant longs et coûteux, la simulation numérique de l’accrétion de givre est devenueun outil nécessaire dans le processus de conception et de certification des avions. Cette thèse s’inscrit dans le contexte de la modélisation 3D de l’accrétion de givre, et plus particulièrement des couches limites dynamique et thermique qui se développent autour du corps givré. Les outils numériques devant être rapides et robustes, l’approche proposée dans cette thèse pour le calcul aérodynamique est une méthode couplée Euler/couche limite intégrale. Ainsi, un modèle intégral est développé pour représenterle développement de la couche limite dynamique. La partie thermique est modélisée soit par une méthodesimplifiée basée sur des approches algébriques, soit par une méthode intégrale. Cette modélisation des coucheslimites dynamique et thermique est valable sur paroi lisse ou rugueuse et permet de fournir notamment lecoefficient de frottement et le coefficient d’échange thermique qui sont nécessaires pour un calcul d’accrétion degivre. Les équations intégrales de couche limite, associées à leurs relations de fermeture, sont ensuite résoluespar une méthode Volumes-Finis sur maillage surfacique non structuré, qui est bien adaptée pour les géométriescomplexes. De plus, des traitements numériques spécifiques sont mis en œuvre pour améliorer la précision dela méthode au voisinage du point d’arrêt et pour rendre le code robuste au passage du décollement.Après la validation de la méthode de couche limite, le code est utilisé dans les chaînes de givrage 2D et 3Dde l’ONERA pour des applications d’accrétion de givre. Ceci permet de montrer l’intérêt de la méthode entermes de robustesse et de précision par rapport aux codes de couche limite habituellement utilisés dans lescodes de givrage actuels Icing has since long been identified as a serious issue in the aeronautical world. Ice accretion occurs whensupercooled water droplets impinge on a surface, particularly the leading edge of a wing or an engine inlet, andfreeze after the impingement. This can lead to degradation of aerodynamic performances, sensor malfunctionor engine damage. This is why this issue is being carefully studied. The lengthy and costly flight and windtunnel tests have made numerical simulation of ice accretion a necessary tool in the aircraft design andcertification process. The present work deals with the 3D numerical modeling of ice accretion, and more particularly the modeling of the dynamic and thermal boundary layers that develop around an iced body. Since numerical tools must befast and robust, the approach proposed in this thesis for aerodynamic computation is a coupled Euler/integralboundary layer method. Thus, an integral model is developed to represent the development of the dynamicboundary layer. The thermal part is modeled either by a simplified method based on algebraic approaches,or by an integral method. This modeling of the dynamic and thermal boundary layers is valid on smoothor rough walls and provides the friction coefficient and heat exchange coefficient that are necessary for thecalculation of ice accretion. The integral boundary layer equations, associated with their closure relations,are then solved by a Finite-Volume method on unstructured surface mesh, that is well suited for complexgeometries. In addition, specific numerical treatments are implemented to improve the accuracy of the methodin the vicinity of the stagnation point and to make the code robust to separated boundary layers.After validation of the boundary layer method, the code is used in ONERA’s 2D and 3D icing tools foricing applications. This demonstrates the value of the method in terms of robustness and accuracy comparedto the boundary layer codes more commonly used in current icing tools

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Gomes, Francisco Augusto Aparecido. "Estudo analítico/numérico do problema de ablação em corpos rombudos com simetria axial /." Ilha Solteira : [s.n.], 2006. http://hdl.handle.net/11449/88887.

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Resumo: O fenômeno da ablação é um processo que envolve o estudo de proteções térmicas, com muitas aplicações, principalmente na engenharia mecânica e aeroespacial. O processo envolve transferência de calor com movimento de fronteira, onde a posição é desconhecida a priori. As equações governantes do processo formam um sistema não-linear de equações diferenciais acoplado. A análise unidimensional do processo ablativo é realizada em um corpo de revolução, o qual está sobre intenso aquecimento. Esse problema é resolvido utilizando a Técnica da Transformada Integral Generalizada - TTIG, para solução do sistema de equações governantes. Como condição de contorno é considerada um fluxo de calor transiente no contorno, como por exemplo, o que ocorre com veículos na reentrada da atmosfera. A teoria do fluxo de calor de Tauber e de Van Driest é utilizada nessa análise. Os resultados de interesse são, a espessura e a taxa de material ablatado. Os resultados obtidos são comparados com resultados disponíveis de outras técnicas de solução em literaturas. Abstract: The phenomenon of ablation is a process of thermal protection with several applications, mainly, in mechanical and aerospace engineering. This process involves heat transfer with a moving boundary which position is unknown a priori. The governing equations of the process are a non-linear system of coupled partial differential equations. The onedimensional analysis of ablative process has been done in a revolution body, which is on intense heating. This problem is performed by using the generalized integral transform technique - GITT for solution of the system of governing equations. As boundary condition is considered a transient heat flux like ones that occur, for example, in re-entrance of aerospace vehicles in the atmosphere. The heat flux theory of Tauber and Van Driest were used in that analysis. The results of interest are the thickness and the rate of loss of the ablative material. The obtained results are compared with available results of other techniques of solution in the literature. Orientador: João Batista Campos Silva Coorientador: Antonio João Diniz Banca: Cássio Roberto Macedo Maia Banca: Paulo Gilberto de Paula Toro Mestre

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Souza, Luís Henrique Gazeta de. "Aplicação da transformada integral generalizada no escoamento potencial em contrações /." Ilha Solteira : [s.n.], 2009. http://hdl.handle.net/11449/88871.

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Orientador: João Batista Aparecido Banca: Cassio Roberto Macedo Maia Banca: Alcides Padilha Resumo: Realiza-se a formulação matemática do escoamento potencial no interior de contrações bidimensionais usando sistemas de coordenadas cartesianas e cilíndricas. Para tal considera-se que as geometrias das contrações sejam bidimensionais no sistema de coordenadas cartesianas e bidimensionais com simetria axial no sistema de coordenadas cilíndricas. A formulação é adaptada a partir das equações tridimensionais de Euler em coordenadas cartesianas e cilíndricas, fazendo-se as hipóteses de bidimensionalidade, regime permanente, fluido invíscido e escoamento irrotacional. O formalismo diferencial do escoamento potencial no interior de contrações bidimensionais é formalmente resolvido utilizando-se a Técnica da Transformada Integral Generalizada - TTIG - cuja fundamentação está na expansão de funções-quadrado-integráveis em séries de funções ortogonais. Desenvolveu-se algoritmos computacionais, em linguagem computacional Fortran 95, para simular as soluções formais obtidas e produzir resultados numéricos que possibilitassem a análise do escoamento potencial nas referidas contrações. Realizou-se extensivos testes numéricos para quatro famílias de geometrias das contrações, sendo que cada família ainda possuía diferentes funções modeladoras do formato de suas paredes, bem como os parâmetros razão e esbeltez e razão de contração. Analisou-se os resultados visando sintetizar aspectos e características de como as contrações operam e que formatos são mais adequados ou não Abstract: It was done the mathematical formulation for potential flow inside two-dimensional contractions using both Cartesian and cylindrical coordinate systems. To achieve such aim it was considered that contraction geometries are two-dimensional in the Cartesian coordinate system and two-dimensional with axial symmetry in cylindrical system. Formulation is adapted from tri-dimensional Euler equations in Cartesian and cylindrical coordinate systems, doing hypothesis such as: two-dimensionality, steady flow regime, inviscid fluid and irrotational flow. Differential formulae that models potential flow inside two-dimensional contraction is formally solved using Generalized Integral Transform Technique - GITT - which is based upon orthogonal series expansion of square-integrable functions. It was developed some computational algorithms, using Fortran 95 computational language, to simulate the obtained formal solutions and to produce numerical results that allows potential flow analysis for referred contractions. It was done comprehensive numerical tests for four families of contraction geometries, being that each family yet has different contraction wall modeling functions, as well length and contraction ratios. Results were analyzed aiming to synthesize aspects and characteristics of how contractions operate and which forms are more adequate or not Mestre

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32

Mouhat, Félix. "Fully quantum dynamics of protonated water clusters." Electronic Thesis or Diss., Sorbonne université, 2018. http://www.theses.fr/2018SORUS056.

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De nos jours, il n'existe encore aucune théorie capable de proposer une description précise et quantitative du transfert de proton en solution. En effet, ce problème est complexe du fait de la grande diversité des interactions existant dans l'eau liquide, à savoir: des interactions non liantes de type Van der Waals, des liaisons faiblement covalentes et des liaisons hydrogènes remarquablement fortes. Ces dernières sont d'ailleurs à l'origine des nombreuses propriétés fascinantes de l'eau à l'échelle macroscopique. À cela s'ajoutent les effets quantiques nucléaires dus à la faible masse de l'hydrogène, qui modifient profondément la nature de la surface d'énergie potentielle décrivant le transfert de proton le long de sa coordonnée de réaction. Nous proposons dans cette thèse une approche tout quantique basée sur une description quasi exacte de la fonction d'onde du système par l'utilisation de méthodes stochastiques de type Monte Carlo Quantique. Cette technique, combinée avec le formalisme des équations de Langevin et des intégrales de chemin de Feynman, permet de simuler à un niveau de précision inédit, n'importe quel système chimique en phase gaz ou en solution. Nous appliquons cette méthodologie à des agrégats d'eau neutres ou protonés pour apporter de nouveaux éclaircissements sur les phénomènes microscopiques régissant la diffusion du proton hydraté dans de tels systèmes. Il est mis en évidence que la mobilité du proton est optimale pour des températures proches des conditions ambiantes, du fait de la compétition subtile entre les effets thermiques et quantiques nucléaires There is no theory up to now able to provide an accurate and quantitative description of the proton transfer (PT) yet. Indeed, the complexity of the problem stems from the large diversity of the existing interactions in liquid water, namely: non bonding Van der Waals interactions, weakly covalent bonds and remarkably strong H-bonds. The latter ones are at the origin of the numerous fascinating properties of water at the macroscopic scale. In addition to such interactions, the nuclear quantum effects arising from the hydrogen light mass deeply modify the potential energy surface, and must be taken into account. In this thesis, we propose a fully quantum approach based on an almost exact description of the electronic wave function by means of Quantum Monte Carlo (QMC) methods. Our novel technique combines QMC with a Langevin-based Molecular Dynamics and the Feynman's path integral formalism. This allows one to perform fully quantum simulations of systems in gas or condensed phase, at an unprecedented level of accuracy,. We apply our approach to neutral or charged protonated water clusters to shed light on the microscopic phenomena driving the proton diffusion in such systems. We discovered that the proton hopping is optimal for temperatures close to ambient conditions, due to the subtle competition between thermal and nuclear quantum effects. This is highly suggestive of the importance of quantum nuclear effects to make PT processes - relevant for life - most efficient at room temperature

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33

Sanja, Kostadinova. "Some classes of integral transforms on distribution spaces and generalized asymptotics." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2014. https://www.cris.uns.ac.rs/record.jsf?recordId=87772&source=NDLTD&language=en.

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In this doctoral dissertation several integral transforms are discussed.The first one is the Short time Fourier transform (STFT). We present continuity theorems for the STFT and its adjoint on the test function space K1(ℝn) and the topological tensor product K1(ℝn) &otimes; U(ℂn), where U(ℂn) is the space of entirerapidly decreasing functions in any horizontal band of ℂn. We then use such continuity results to develop a framework for the STFT on K'1(ℝn). Also, we devote one section to the characterization of K’1(ℝn) and related spaces via modulation spaces. We also obtain various Tauberian theorems for the short-time Fourier transform.Part of the thesis is dedicated to the ridgelet and the Radon transform. We define and study the ridgelet transform of (Lizorkin) distributions and we show that the ridgelet transform and the ridgelet synthesis operator can be extended as continuous mappings Rψ : S’0(ℝn) → S’(Yn+1) and Rtψ: S’(Yn+1) → S’0(ℝn). We then use our results to develop a distributional framework for the ridgelet transform that is, we treat the ridgelet transform on S’0(ℝn) via a duality approach. Then, the continuity theorems for the ridgelet transform are applied to discuss the continuity of the Radon transform on these spaces and their duals. Finally, we deal with some Abelian and Tauberian theorems relating the quasiasymptotic behavior of distributions with the quasiasymptotics of the its Radon and ridgelet transform.The last chapter is dedicated to the MRA of M-exponential distributions. We study the convergence of multiresolution expansions in various test function and distribution spaces and we discuss the pointwise convergence of multiresolution expansions to the distributional point values of a distribution. We also provide a characterization of the quasiasymptotic behavior in terms of multiresolution expansions and give an MRA sufficient condition for the existence of α-density points of positive measures. U ovoj doktorskoj disertaciji razmotreno je nekoliko integralnih transformacija. Prva je short time Fourier transform (STFT). Date su i dokazane teoreme o neprekidnosti STFT i njena sinteza na prostoru test funkcije K1(ℝn) i na prostoru K1(ℝn) &otimes; U(ℂn), gde je U(ℂn) prostor od celih brzo opadajućih funkcija u proizvoljnom horizontalnom opsegu na ℂn. Onda, ovi rezultati neprekidnosti su iskori&scaron;teni za razvijanje teorije STFT na prostoru K’1(ℝn). Jedno poglavlje je posvećeno karakterizaciji K’1(ℝn) sa srodnih modulaciskih prostora. Dokazani su i različiti Tauberovi rezultata za STFT. Deo teze je posvećen na ridglet i Radon transformacije. Ridgelet transformacija je definisana na (Lizorkin) distribucije i pokazano je da ridgelet transformacija i njen operator sinteze mogu da se pro&scaron;ire kako neprekidna preslikava Rψ : S’0(ℝn) → S’(Yn+1) and RtΨ: S’(Yn+1) → S’0(ℝn). Ridgelet transformacija na S’0(ℝn) je data preko dualnog pristupa. Na&scaron;e teoreme neprekidnosti ridgelet transformacije su primenjene u dokazivanju neprekidnosti Radonove transformacije na Lizorkin test prostorima i njihovim dualima. Na kraju, dajemo Abelovih i Tauberovih teorema koji daju veze izmedju kvaziasimptotike distribucija i kvaziasimptotike rigdelet i Radonovog transfomaciju.Zadnje poglavje je posveceno multirezolucijskog analizu M - eksponencijalnih distrubucije. Proucavamo konvergenciju multirezolucijkog razvoja u razlicitih prostori test funkcije i distribucije i razmotrena je tackasta konvergencija multirezolucijkog razvoju u tacku u distributivnog smislu. Obezbedjena je i karakterizacija kvaziasimptotike u pogled multirezolucijskog razvoju i dat dovoljni uslov za postojanje α-tacka gustine za pozitivne mere.

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Alves, Thiago Antonini [UNESP]. "Aplicação da transformada integral e da transformação conforme na solução de uma classe de problemas difusivo-convectivos em domínios de geometrias não-convencionais." Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/88876.

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Made available in DSpace on 2014-06-11T19:23:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-08-18Bitstream added on 2014-06-13T18:48:07Z : No. of bitstreams: 1 alves_ta_me_ilha.pdf: 8112255 bytes, checksum: 408af7eb63e2a3050e7bda3fd133d8cf (MD5) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) O presente trabalho trata da solução de uma classe de problemas difusivo-convectivos, tanto de natureza elíptica como parabólica, em domínios de geometrias não-convencionais, através da aplicação da Transformada Integral. Para facilitar o tratamento analítico e a aplicação das condições de contorno, antes da aplicação da Técnica da Transformada Integral Generalizada - TTIG sobre a equação governante do problema estudado, emprega-se uma Transformação Conforme - TC visando efetuar uma mudança de coordenadas adequada. Analisa-se inicialmente o problema hidrodinâmico do escoamento laminar completamente desenvolvido de fluidos Newtonianos no interior de dutos. Para a obtenção do campo de velocidades do escoamento aplica-se a TTIG sobre a equação da quantidade de movimento. Os parâmetros hidrodinâmicos de interesse, tais como: velocidades média e máxima, fator de atrito de Fanning, fator de Hagenbach, número de Poiseuille, comprimento de entrada hidrodinâmico e queda de pressão são calculados para as diversas geometrias. Feito isso, efetua-se o estudo dos problemas difusivo-convectivos relacionados à transferência de calor do escoamento laminar hidrodinamicamente desenvolvido e termicamente em desenvolvimento de fluidos Newtonianos com perfil de temperatura de entrada uniforme em dutos submetidos a condições de contorno de Dirichlet. Para a obtenção do campo de temperatura aplica-se a TTIG sobre a equação da energia e então, calculam-se os parâmetros térmicos de interesse: temperatura média de mistura, números de Nusselt local e médio e comprimento de entrada térmica. Realiza-se, quando possível, a comparação dos resultados obtidos para os parâmetros termos-hidráulicos com os disponíveis na literatura. The present work describes the solution of a class of elliptical-parabolic diffusiveconvective problems, on unconventional geometries, employing the Generalized Integral Transform Technique (GITT). In order to facilitate the analytical treatment and the application of the boundary conditions, a Conformal Transform (CT) is used to change the domain into a more suitable coordinate system, just before GITT is to be applied. First of all, using this procedure, the hydrodynamic problem of fully developed Newtonian laminar flow inside ducts is analyzed. In order to obtain the velocity field, GITT is applied on the momentum equation. Interesting hydrodynamic parameters, such as: maximum and minimum velocity values, Fanning friction and Hagenbach factors, Poiseuille number, hydrodynamic entry length, as well as pressure loss, are evaluated for several geometries. Following that, diffusive-convective problems are studied in relationship to the heat transfer in hydrodynamically fully developed and thermally non-developed Newtonian laminar flow inside ducts under Dirichlet boundary conditions, considering uniform temperature entrance profile. In order to obtain the temperature field, GITT is applied on the energy equation, evaluating the relevant parameters: bulk mean temperature, average and local Nusselt numbers and thermal entry length. The results are compared, as much as possible, with the parameter values available in the literature.

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Rastandi, Josia Irwan. "Modelization of dynamic soil-structure interaction using integral transform-finite element coupling." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=970018614.

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Chibawara, Trust. "Pricing and hedging asian options using Monte Carlo and integral transform techniques." Thesis, Stellenbosch : University of Stellenbosch, 2010. http://hdl.handle.net/10019.1/4292.

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Thesis (MSc (Mathematics))--University of Stellenbosch, 2010. ENGLISH ABSTRACT: In this thesis, we discuss and apply the Monte Carlo and integral transform methods in pricing options. These methods have proved to be very e ective in the valuation of options especially when acceleration techniques are introduced. By rst pricing European call options we have motivated the use of these methods in pricing arithmetic Asian options which have proved to be di cult to price and hedge under the Black􀀀Scholes framework. The arithmetic average of the prices in this framework, is a sum of correlated lognormal distributions whose distribution does not admit a simple analytic expression. However, many approaches have been reported in the academic literature for pricing these options. We provide a hedging strategy by manipulating the results by Geman and Yor [42] for continuous xed strike arithmetic Asian call options. We then derive a double Laplace transform formula for pricing continuous Asian call options following the approach by Fu et al. [39]. By applying the multi-Laguerre and iterated Talbot inversion techniques for Laplace transforms to the resulting pricing formula we obtain the option prices. Finally, we discuss the shortcomings of using the Laplace transform in pricing options. AFRIKAANSE OPSOMMING: In hierdie tesis bespreek ons Monte Carlo- en integraaltransform metodes om die pryse van nansi ele opsies te bepaal. Hierdie metodes is baie e ektief, veral wanneer versnellingsmetodes ingevoer word. Ons bepaal eers die pryse van Europese opsies as motivering, voordat ons die bostaande metodes gebruik vir prysbepaling van Asiatiese opsies met rekenkundige gemiddeldes, wat baie moeiliker is om te hanteer in die Black􀀀Scholes raamwerk. Die rekenkundige gemiddelde van batepryse in hierdie raamwerk is 'n som van gekorreleerde lognormale distribusies wie se distribusie nie oor 'n eenvoudige analitiese vorm beskik nie. Daar is egter talle benaderings vir die prysbepaling van hierdie opsies in die akademiese literatuur. Ons bied 'n verskansingsstrategie vir Asiatiese opsies in kontinue tyd met 'n vaste trefprys aan deur die resultate van Geman en Yor [42] te manipuleer. Daarna volg ons Fu et al. [39] om 'n dubbele Laplace transform formule vir die pryse af te lei. Deur toepassing van multi-Laguerre en herhaalde Talbotinversie tegnieke vir Laplace transforms op hierdie formule, bepaal ons dan die opsiepryse. Ons sluit af met 'n bespreking van die tekortkominge van die gebruik van die Laplace transform vir prysbepaling.

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Pavel, Dimovski. "Translation invariant Banach spaces of distributions and boundary values of integral transform." Phd thesis, Univerzitet u Novom Sadu, Prirodno-matematički fakultet u Novom Sadu, 2015. https://www.cris.uns.ac.rs/record.jsf?recordId=93767&source=NDLTD&language=en.

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We use common notation &lowast; for distribution (Scshwartz), (Mp) (Beurling) i {Mp} (Roumieu) setting. We introduce and study new (ultra) distribution spaces, the test function spaces D&lowast;E  and their strong duals D'&lowast;E’*.These spaces generalize the spaces D&lowast;Lq , D'&lowast;Lp , B’* and their weighted versions. The construction of our new (ultra)distribution  spaces is based on the analysis of a suitable translation-invariant Banach space of (ultra)distribution E with continuous translation group, which turns out to be a convolution module over the Beurling algebra L1ω, where the weight  ω is related to the translation operators on E. The Banach space E’&lowast; stands for L1ωˇ &lowast; E’. We apply our results to the study of the convolution of ultradistributions. The spaces of convolutors O’&lowast;C (Rn) for tempered ultradistributions are analyzed via the duality with respect to the test functionspaces O&lowast;C (Rn), introduced in this thesis. Using the properties of translationinvariantBanach space of ultradistributions E we obtain a full characterization ofthe general convolution of Roumieu ultradistributions via the space of integrableultradistributions is obtained. We show: The convolution of two Roumieu ultradistributions T, S ∈ D’{Mp} (Rn)  exists if and only if (φ &lowast; &Scaron;) T ∈ D’{Mp}L1(Rn)  for every φ ∈ D {Mp} (Rn). We study boundary values of holomorphic functions defined in tube domains. New edge of the wedge theorems are obtained. The resultsare then applied to represent D’E’*  as a quotient space of holomorphic functions.We also give representations of elements of D’E’*  via the heat kernel method. Koristimo oznaku &lowast; za distribuciono (Svarcovo), (Mp) (Berlingovo) i {Mp} (Roumieuovo) okružeǌe. Uvodimo i prouavamo nove (ultra)distribucione prostore,  test funkcijske prostore D&lowast;E i ǌihove duale D'&lowast;E'*.  Ovi prostori uop&scaron;tavaju prostore D&lowast;Lq , D'&lowast;Lp , B'&lowast; i ǌihove težinske verzije. Konstrukcija na&scaron;ih novih (ultra)distribucionih prostora je zasnovana na analizi odgovarajuićh translaciono - invarijantnih Banahovih prostora (ultra)distribucija koje označavamo sa E. Ovi prostori imaju neprekidnu grupu translacija, koja je konvolucioni modul nad  Beurlingovom algebrom L1ω, gde je težina ω povezana sa operatorima translacije prostora E. Banahov prostor E'&lowast; označava prostor L1ω˅ &lowast; E'. Koristeći dobijene rezultata proučavamo konvoluciju ultradistribucija. Prostori konvolutora  O'&lowast;C (Rn) temperiranih ultradistribucija, analizirani su pomoću dualnosti test funkcijskih prostora O&lowast;C (Rn), definisanih u ovoj tezi. Koristeći svojstva translaciono - invarijantnih Banahovih prostora temperiranih ultradistribucija, opet označenih sa E, dobijamo karakterizaciju konvolucije Romuieu-ovih  ultradistribucija, preko integrabilnih ultradistribucija. Dokazujemo da: konvolucija dve Roumieu-ove ultradistribucija T, S ∈ D'{Mp} (Rn) postoji ako i samo ako (φ &lowast; Sˇ)T ∈ D'{Mp} L1 (Rn) za svaki φ ∈ D{Mp}(Rn). Takođe, proučavamo granične vrednosti holomorfnih funkcija definisanih na tubama. Dokazane su nove teoreme ”otrog klina”. Rezultati se zatim koriste za prezentaciju D'E'&lowast; preko faktor prostora holomorfnih funkcija. Takođe, data je prezentacija elemente D'E'&lowast; koristeći heat kernel metode.

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Huang, Min. "Applications of integral transform methods to the Schroedinger equation and dynamical systems." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1277345391.

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Xu, Rui Hui. "Windowed linear canonical transform and its applications." Thesis, University of Macau, 2011. http://umaclib3.umac.mo/record=b2493220.

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Mohamed, Fathi Husain Alhadi. "Mitigation of Amplitude and Phase Distortion of Signals Under Modified Von Karman Turbulence Using Encrypted Chaos Waves." University of Dayton / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1467943201.

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Bacca, Sonia. "Study of electromagnetic reactions on light nuclei with the Lorentz integral transform method." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=976128365.

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Skokan, Michal. "Regularity of ghosts of geodesic X-ray transform /." Thesis, Connect to this title online; UW restricted, 2004. http://hdl.handle.net/1773/5744.

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Poliak, Juraj. "Vliv optických prvků na vyzařovaný laserový svazek." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2011. http://www.nusl.cz/ntk/nusl-219107.

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Diplomová práca pojednáva o skalárnej teórii difrakcie a zavádza dôležité riešenie vlnovej rovnice a to elipticky symetrický Gaussov zväzok. V praktickej časti bude popísané modelovanie difrakcie na kruhovom otvore dvoma rôznymi prístupmi. Model bude experimentálne overený experimentom. V záverečnej časti bude kriticky pojednané o výsledkoch experimentu a simulácie.

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Ballard, Grey M. "Asymptotic behavior of the eigenvalues of Toeplitz integral operators associated with the Hankel transform." Electronic thesis, 2008. http://dspace.zsr.wfu.edu/jspui/handle/10339/221.

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Al-Jabri, Zaaima. "Analysis of integrase and transposase-mediated mechanisms for transfer of mobile genetic elements." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42501.

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Mobile genetic elements (MGE) are DNA segments most of which are capable of their own self mobilisation through genes either intracellularly (transposase or integrase genes) or intercellularly (conjugation genes), thus both contributing in bacterial evolution. This thesis investigated the functions of two distinct integrase genes in the mobilisation of two metal resistance GIs, G08 and G62, of Acinetobacter baumannii. G8int encodes a novel family of phage-type integrases whereas the G62int gene encodes a classic phage-type integrase. In addition, the role of transposon-mobilised resistance genes have been addressed in a number of Staphylococcus epidermidis clinical isolates, conferring resistance to biocides by way of the metabolic ileS and fabI genes. Real-time PCR demonstrated integrase dependent GI excision, utilising IPTG-inducible integrase genes in plasmid-based mini-GIs in E. coli. In A. baumannii integrase-dependent excision of the original chromosomal GIs could be observed after mitomycin C induction. In both E. coli and A. baumannii the rate of excision and circularisation was found to be dependent on the expression level of the recombinases. Susceptibility testing in A. baumannii strains ATCC 17978, A424 and their respective ΔG62 and ΔG08 mutants confirmed the contribution of the GI-encoded efflux transporters to heavy metal resistance mainly for copper. In S. epidermidis, the distribution and phenotypes of the insertion-sequence mobilised ileS2 gene on mupirocin resistance and sh-fabI gene on tricolsan resistance is described in this study and the novel type of mobilization of the sh-fabI carrying TnSha1 element was investigated. In summary, the data evidence the functionality and essential contribution of two integrases in the mobilisation of the two A. baumannii heavy metal resistance GIs G08 and G62 in E. coli as well as when chromosomally located in their natural host. Moreover, the contribution of additional laterally transferred genes, ileS2 and sh-fabI in reducing the susceptibility to mupirocin and triclosan, respectively was confirmed in the current study. The different transfer mechanisms in both elements result in genomes plasticity participating in the dissemination of resistance determinants in A. baumannii and Staphylococcus species.

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Szabo, Szilard. "Nahm transform for integrable connections on the Riemann sphere." Université Louis Pasteur (Strasbourg) (1971-2008), 2005. http://www.theses.fr/2005STR13072.

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Doroshenko, V. O., N. P. Klimova, N. P. Stognii, and Yu D. Kostyn. "Mathematical Modelling of Impulse Excitation of a Superwideband PEC Cone Antenna." Thesis, 2019 IEEE 8th International Conference on Advanced Optoelectronics and Lasers, CAOL*2019, 2019. https://openarchive.nure.ua/handle/document/16284.

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The method for solving initial-boundary electromagnetic problems is proposed. It uses the Green’s function method and the Laplace and Meler-Fock integral transforms in a time domain. The model problem of special slotted cone antenna excitation is studied. Integral and series representation of electromagnetic field component are given.

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Мартиненков, В. І. "Інноваційний розвиток економіки сільських територій України". Thesis, Чернігів, 2019. http://ir.stu.cn.ua/123456789/18261.

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Мартиненков В. І. Інноваційний розвиток економіки сільських територій України : дис. ... канд. екон. наук : 08 00 03 / В. І. Мартиненков. - Чернігів, 2019. - 259 с. Дисертаційна робота присвячена науковому обґрунтуванню теоретичних засад та організаційно-методичних рекомендацій щодо стимулювання інноваційного розвитку економіки сільських територій України в умовах децентралізації влади з метою підвищення ефективності інноваційної державної політики, результати якої мають спрямовуватися на покращення рівня соціально-економічного та інформаційного забезпечення сільського населення. В роботі було визначено соціоекономічну сутність інноваційного розвитку економіки сільських територій, що дозволило поєднати у цьому понятті інноваційний розвиток економіки сільського господарства та несільськогосподарського виробництва, зосередженого на зазначених територіях. Обґрунтовано необхідність розрахунку відповідного інтегрального індексу, який дозволив виявити, на різних рівнях деталізації, лідерів та аутсайдерів. Використання квадратичних коопуклих сплайнів із високою точністю вказало, що відповідний інтегральний індекс має позитивну динаміку на всьому інтервалі (0,1774–0,1779). Запропонований науковий підхід буде корисним для завершення децентралізації влади, оскільки надає інструментарій для диференційованої державної підтримки інноваційного розвитку сільських об’єднаних громад підвищивши рівень цільового призначення дотацій на умовах субсидіарності. Диссертация посвящена научному обоснованию теоретических основ и организационно-методических рекомендаций по стимулированию инновационного развития экономики сельских территорий Украины в условиях децентрализации власти с целью повышения эффективности инновационной государственной политики, результаты которой должны быть направлены на улучшение уровня социально-экономического и информационного обеспечения сельского населения. На основе комплексного анализа мировых научно-практических исследований в сфере инновационного развития было определено социоэкономическую сущность инновационного развития экономики сельских территорий, что позволило объединить в этом понятии инновационное развитие экономики сельского хозяйства и несельскохозяйственного производства, сосредоточенного на указанных территориях. Автором приведена подробная характеристика инновационного развития сельского хозяйства как одной из основных составляющих инновационного развития экономики сельских территорий Украины подтвердила наличие критической разбалансированности социоэкономической системы. Зафиксировано ухудшение социальной инфраструктуры, обеспечение специалистами высокой квалификации, монопроизводство, уменьшение темпов развития животноводства, которое в свою очередь негативно повлияло на количество внесенных органических удобрений, и по трансцендентному свойству ожидаемо привело к снижению плодородия почв на большинстве сельских территорий Украины. При этом отечественные статистические органы фиксируют существенное увеличение доли сельского хозяйства в ВВП страны и непрерывное рост рентабельности и доходов сельскохозяйственных бизнес структур. Неравномерность распределения ряда показателей, влияющих на инновационное развитие экономики сельских территорий, а также расчет соответствующего интегрального индекса, в частности, позволили указать пути минимизации зависимости от импорта природного газа через использование залежей торфа, леонардита и других полезных веществ, а также соломы и отходов. Приведенный алгоритм определения интегрального индекса инновационного развития экономики сельских территорий позволил выявлять, на разных уровнях детализации, лидеров в инновационном развитии экономики сельских территорий. При этом проведена независимая оценка весов девяти субиндексов на основе модернизированной системы индикаторов и их пороговых и предельно допустимых значений. Расчеты показали, что наиболее влиятельными на уровень инновационного развития экономики сельских территорий Украины есть индикаторы, характеризующие инновационное развитие органического производства, освоение капитальных инвестиций в сельское хозяйство, количество специалистов, выполняющих научные и научно-технические работы (0,1-0,3), а наименее влиятельным – индикатор, характеризующий капитальные инвестиции в земельные ресурсы (0,09). Указанное позволяет точнее прогнозировать динамику инновационного развития экономики сельских территорий как важнейшей составляющей государственной инновационной политики. Доказано, что благодаря распределению областей Украины по уровню инновационного развития сельских территорий, указывающему на существенные диспропорции и чрезмерную централизацию инновационного развития вокруг столицы Украины и больших городов-миллионников (в частности, Харькова) возможно усовершенствовать систему принятия управленческих решений на государственном и местном уровне. Аргументировано, что проведенное экономико-математические моделирование, на основе которого получено фактические и прогнозные расчеты, позволяет минимизировать ряд рисков (в том числе и социоэкономических), которые будут проявляться при завершении процесса децентрализации, когда каждая область будет состоять из нескольких объединенных территориальных общин, которые будут иметь собственные отделы статистики и смогут проводить расчеты с большей степенью детализации. Предложенный методический инструментарий позволил построить концепт модели дальнейшего инновационного развития экономики сельских территорий в рамках стратегии социально-экономического развития сельских объединенных территориальных общин. Усовершенствованы научные подходы к моделированию и прогнозированию инновационного развития экономики сельских территорий Украины на основе адаптивного прогнозирования с использованием квадратичных коопуклых сплайнов позволили с высокой точностью указать, что соответствующий интегральный индекс будет имеет положительную динамику на всем интервале (0,1774–0,1779) до 2020 г. включительно. Но низкие скалярные значения интегрального индекса инновационного развития экономики сельских территорий Украины указывают на необходимость дополнительной адресной государственной поддержки сельских территориальных общин. Предложенный научный подход будет полезным для завершения процессов децентрализации власти, поскольку предоставляет инструментарий для дифференцированной государственной поддержки инновационного развития сельских объединенных общин повысив уровень целевого назначения дотаций на условиях субсидиарности. The thesis is devoted to scientific substantiation of theoretical principles and organizational guidelines to stimulate innovative economic development of rural areas in Ukraine in terms of decentralization of power in order to enhance innovative public policies, the results of which are directed at improving the socio-economic and informational support of the rural population. The work was defined socioeconomic essence of innovative economic development of rural areas, which allowed this concept to combine innovative economy of agriculture and agricultural production concentrated in these areas. The necessity of the calculation of the integral index, which revealed, at different levels of detail, leaders and outsiders. Use coconvex quadratic spline high precision indicated that the corresponding integral index has positive dynamics across the range (0,1774–0,1779). The proposed scientific approach would be useful to complete the decentralization of power, as it provides tools for differentiated state support of innovative development of rural communities united by raising the level purpose grants on terms of subsidiarity.

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Bishop, Shannon Renee Smith. "Gabor and wavelet analysis with applications to Schatten class integral operators." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/33976.

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Abstract:

This thesis addresses four topics in the area of applied harmonic analysis. First, we show that the affine densities of separable wavelet frames affect the frame properties. In particular, we describe a new relationship between the affine densities, frame bounds and weighted admissibility constants of the mother wavelets of pairs of separable wavelet frames. This result is also extended to wavelet frame sequences. Second, we consider affine pseudodifferential operators, generalizations of pseudodifferential operators that model wideband wireless communication channels. We find two classes of Banach spaces, characterized by wavelet and ridgelet transforms, so that inclusion of the kernel and symbol in appropriate spaces ensures the operator is Schatten p-class. Third, we examine the Schatten class properties of pseudodifferential operators. Using Gabor frame techniques, we show that if the kernel of a pseudodifferential operator lies in a particular mixed modulation space, then the operator is Schatten p-class. This result improves existing theorems and is sharp in the sense that larger mixed modulation spaces yield operators that are not Schatten class. The implications of this result for the Kohn-Nirenberg symbol of a pseudodifferential operator are also described. Lastly, Fourier integral operators are analyzed with Gabor frame techniques. We show that, given a certain smoothness in the phase function of a Fourier integral operator, the inclusion of the symbol in appropriate mixed modulation spaces is sufficient to guarantee that the operator is Schatten p-class.

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Pipkins, Daniel Scott. "Non-linear analysis of (i) wave propagation using transform methods and (ii) plates and shells using integral equations." Diss., Georgia Institute of Technology, 1992. http://hdl.handle.net/1853/20052.

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Dissertations / Theses on the topic 'Transfer integral'

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