Thesis (M.S.)--University of Wisconsin--Madison, 1969. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Master's). / Naval Postgraduate School technical report Title from cover. "NPS-OR-99-002." "February 1999." Includes bibliographical references (p. 13).

Thesis (doctoral)--Rheinische Friedrich-Wilhelms-Universität Bonn, 1997. / Includes bibliographical references (p. 133-134).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1968. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 140-143).

Thesis (Ph. D.)--Illinois State University, 1995. / Title from title page screen, viewed May 2, 2006. Dissertation Committee: John A. Dossey (chair), Stephen H. Friedberg, Beverly S. Rich, Kenneth Strand, Jane O. Swafford. Includes bibliographical references (leaves 93-97) and abstract. Also available in print.

Made available in DSpace on 2014-06-11T19:31:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2008-08-25Bitstream added on 2014-06-13T19:21:04Z : No. of bitstreams: 1 toledo_jc_dr_rcla.pdf: 2561466 bytes, checksum: b6bae6e58494225b01dca9e6ae51e81d (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Este trabalho - uma investigação inserida no campo da História da Matemática ­argumenta em favor da existência, no Brasil, de uma tradição em pesquisa na área de Análise Matemática e propõe uma narrativa historiadora sobre o processo de institucionalização dessa área no país. Algumas práticas sociais no âmbito da comunidade de analistas brasileiros são enfatizadas: umas, por terem sido cruciais para os processos locais de constituição e autonomização desse campo científico; outras, por conferirem à Análise, o status de área institucionalizada no país. / This work - an investigation inserted in the field of the History of Mathematics argues in favour of a tradition in research in the area of Mathematical Analysis in Brazil and proposes a narrative history about the process of institutionalization of this area here. Some social practices within the community of brazilian analysts are emphasized: one, because they have been crucial to the constitution and autonomization of this scientific field in Brazil; others, by giving to the Analysis the status of an institutionalized area in this country.

Orientador: Sergio Roberto Nobre / Banca: Ligia Arantes Sad / Banca: Simone Mazzini Bruschi / Banca: Carlos Henrique Barbosa Gonçalves / Banca: Antonio Vicente Marafioti Garnica / Possui anexo cd-rom com o Corpus documental da tese / Resumo: Este trabalho - uma investigação inserida no campo da História da Matemática ­argumenta em favor da existência, no Brasil, de uma tradição em pesquisa na área de Análise Matemática e propõe uma narrativa historiadora sobre o processo de institucionalização dessa área no país. Algumas práticas sociais no âmbito da comunidade de analistas brasileiros são enfatizadas: umas, por terem sido cruciais para os processos locais de constituição e autonomização desse campo científico; outras, por conferirem à Análise, o status de área institucionalizada no país. / Abstract: This work - an investigation inserted in the field of the History of Mathematics argues in favour of a tradition in research in the area of Mathematical Analysis in Brazil and proposes a narrative history about the process of institutionalization of this area here. Some social practices within the community of brazilian analysts are emphasized: one, because they have been crucial to the constitution and autonomization of this scientific field in Brazil; others, by giving to the Analysis the status of an institutionalized area in this country. / Doutor

This thesis concerns the water wave problem corresponding to a piecewise constant vorticity function. There are several results connected to this field. In [1] the authors prove the existence of small-amplitude capillary-gravity water waves in the setting of unidirectional waves, and present an explicit form of the dispersion equation in the case when the vorticity function has two jumps. A two-layer model with constant but different vorticities is studied in [2], while in [3], an analysis of the dispersion equation for a three-layer model is given. In this thesis we first classify all stream solutions to the problem specified above, and then use our classification to prove and analyze solubility of the dispersion equation for a vorticity function with one jump. We do not require streams to be unidirectional (that is, we allow underlying counter-currents and internal stagnation).

Numerical approximations using high order finite differences on summation-byparts (SBP) form are investigated for discontinuous and fully nonlinear systems of partial differential equations. Stability and conservation properties of the approximations are obtained through a weak imposition of interface and boundary conditions with the simultaneous-approximation-term (SAT) technique. The SBP-SAT approximations replicate the continuous integration by parts rule. From this property, well-posedness and integral properties of the continuous problem are mimicked, and energy estimates leading to stability are obtained. The first part of the thesis focuses on the simulations of discontinuous linear advection problems. An artificial interface is introduced, separating parts of the spatial domain characterized by different wave speeds. A set of flexible stability conditions at the interface are derived, which can be adapted to yield conservative or non-conservative approximations. This model can be interpreted as a simplified version of nonlinear problems involving jumps at shocks, or as a prototypical of wave propagation through different materials. In the second part of the thesis, the vorticity/stream function formulation of the nonlinear momentum equation for an incompressible inviscid fluid is considered. SBP operators are used to derive a new Arakawa-like Jacobian with mimetic properties by combining different consistent approximations of the convection terms. Energy and enstrophy conservation is obtained for periodic problems using schemes with arbitrarily high order of accuracy. These properties are crucial for long-term numerical calculations in climate and weather forecasts or ocean circulation predictions. The third and final contribution of the thesis is dedicated to the incompressible Navier-Stokes problem. First, different completely general formulations of energy bounding boundary conditions are derived for the nonlinear equations. The boundary conditions can be used at both far field and solid wall boundaries. The discretisation in time and space with weakly imposed initial and boundary conditions using the SBP-SAT framework is proved to be stable and the divergence free condition is approximated with the design order of the scheme. Next, the same formulations are considered in a linearised setting, whereupon the spectra associated with the initial boundary value problem and its SBP-SAT discretisation are derived using the Laplace-Fourier technique. The influence of different boundary conditions on the spectrum and in particular the convergence to steady state is studied. / Numeriska approximationer av ekvationer som styr fysikaliska lagar är avgörande i många tillämpningar. Förutom en matematisk modell som kan fånga huvuddragen i ett verkligt problem är det nödvändigt att kunna utföra tillförlitliga simuleringar. Denna avhandling behandlar numeriska approximationer som med hög noggrannhet bevarar både rent matematiska aspekter av ekvationerna så väl som viktiga egenskaper hos modellen. Dessutom ges särskild uppmärksamhet åt modeller med diskontinuiteter och icke-linjära beteenden. Den första delen av avhandlingen handlar om diskontinuerliga problem. Det fysiska rummet kan ha olika egenskaper i olika regioner, något som kan resultera i instabila lösningar. Tillvägagångssättet består av att införa artificiella gränssnitt som skiljer dessa regioneråt. På detta sätt kan varje region behandlas separat, men på liknande sätt. Exempel på naturliga tillämningsområden är vågutbredning genom olika material och jordbävningssimuleringar. I den andra delen av avhandlingen visar vi att om den numeriska approximationen imiterar partiell integration, då följer också de väsentliga egenskaperna hos modellen på ett naturligt sätt. Att fysikaliska egenskaper bevaras är nödvändigt för att bibehålla stabilitet under långa simuleringstider för bland annat geofysiska problem. Den sista delen av avhandlingen är ägnasåt en av de mest använda modellerna inom strömningsmekanik, nämligen Navier-Stokes ekvationer. Studien fokuserar på härledningen av randvillkor som garanterar att lösningen inte växer på ett oförutsett och okontrollerat vis. Slutligen visas att de härledda randvillkoren på ett korrekt och noggrant sätt återskapar den dissipativa mekanism som ger upphov till jämviktstillstånd.

Philosophiae Doctor - PhD / The purpose of this study was to investigate the epistemological obstacles that mathematics students at undergraduate level encounter in coming to understand the limit concept. The role played by language and symbolism in understanding the limit concept was also investigated. A group of mathematics students at undergraduate level at the National University of Lesotho (NUL) was used as the sample for the study. Empirical data were collected by using interviews and questionnaires. These data were analysed using both the APOS framework and a semiotic perspective. Within the APOS framework, the pieces of knowledge that have to be constructed in coming to understand the limit concept are actions, processes and objects. Actions are interiorised into processes and processes are encapsulated into objects. The conceptual structure is called a schema. In investigating the idea of limit within the context of a function some main epistemological obstacles that were encountered when actions were interiorised into processes are over-generalising and taking the limit value as the function value. For example, in finding the limit value L for f(x) as x tends to 0, 46 subjects out of 251 subjects said that they would calculate f(0) as the limit value. This method is appropriate for calculating the limit values for continuous functions. However, in this case, the method is generalised to all the functions. When these subjects encounter situations in which the functional value is equal to the limit value, they take the two to be the same. However, the two are different entities conceptually. / South Africa