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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Budování aritmetické triády ve dvou matematicko-didaktických prostředích: "Sousedé" a "Barevné trojice" / Building of Arithmetical Triads in Two Mathematical-didactical Environments: Neighbours and Coloured Triples

Otradovcová, Dana January 2012 (has links)
The thesis attends to the mathematical charts constructing of additive triad of pupils on 1st grade of the primary school by means of two mathematical - didactic settings "The Neighbours" and "The Coloured Trio". They occure in mathematical textbooks created by prof. RNDr. Milan Hejný, CSc., RNDr. Darina Jirotková, Ph.D., PhDr. Jana Slezáková, Ph.D. and their colleagues and which are published by Fraus. In my thesis I shall attend to the theoretical pieces of knowledge in the given mathematical area as well as to the reasons for the creation of the new mathematical teaching concept after the czech educational reform. Mathematical tasks from the two appointed settings will be handed in to the pupils to be solved. The pupils will encounter such tasks for the first time. It shall be observed how they are able to cope with the given tasks and if they will be able to infiltrate the problem of the tasks or to invent their own tasks. Further on the thesis shall attend to the means of solutions of similar tasks by the students of The Pedagogical Faculty of the Univerzita Karlova and to the analysis of their comments on the tasks.
62

CÁLCULO FINITO: DEMONSTRAÇÕES E APLICAÇÕES

Kondo, Pedro Kiochi 30 September 2014 (has links)
Made available in DSpace on 2017-07-21T20:56:33Z (GMT). No. of bitstreams: 1 Pedro Kiochi Kondo.pdf: 1227541 bytes, checksum: daffb8a8bc299356bce288603753944c (MD5) Previous issue date: 2014-09-30 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this work some topics of the Discrete or Finite Calculus are developed. In particular, we study difference operators, factorial powers, Stirling numbers of the first and second type, the Newton’s formula of differences, the fundamental theorem of the Finite Calculus, the summation process, and the Bernoulli numbers and Bernoulli polynomials. Then we show the effectiveness of the theory for the calculation of closed formulas for the value of many finite sums. We also study the classical problem of obtaining the polynomials which express the value of the sums of powers of natural numbers. / Neste trabalho desenvolvemos alguns tópicos do Cálculo Discreto ou Finito. Em particular, estudamos operadores de diferenças, potências fatoriais, números de Stirling do primeiro e do segundo tipo, a fórmula de diferenças de Newton, o teorema fundamental do Cálculo Finito, o processo de somação e os números e polinômios de Bernoulli. Mostramos então a eficácia da teoria no cálculo de fórmulas fechadas para o valor de diversas somas finitas. Também estudamos o problema clássico de obter os polinômios que expressam o valor de somas de potências de números naturais.
63

When Eyes and Ears Compete: Eye Tracking How Television News Viewers Read and Recall Pull Quote Graphics

Richards, Othello Lennox 01 May 2017 (has links)
This study applied dual processing theory, the theory of working memory, and the theory of cue summation to examine how the video and audio in a television news story interact with or against each other when the story uses pull quote graphics to convey key information to viewers. Using eye-tracking, the study produced visual depictions of exactly what viewers look at on the screen when the words in the reporter's voice track match the text in the pull quote graphic verbatim, when the reporter summarizes the text in the graphic, and when the reporter's voice track ignores the text in the pull quote. The study tested the effect on recall when viewers were presented with these three story conditions—high redundancy, medium redundancy, and low redundancy, respectively. Key findings included the following: first, that stories with low redundancy resulted in lower recall and memory sensitivity scores (a measure of memory strength) than pull quotes that the reporter either summarized or read verbatim on the air. Second, it was found that neither high-redundancy nor medium-redundancy stories were superior or inferior to the other when looking at the effect on recall and memory sensitivity. And finally, in high-, medium-, and low-redundancy conditions, subjects stated that they relied more on the reporter's narration than the pull quote to get information. The study states possible implications for news producers and reporters and suggests future research in the broadcast television news industry.
64

When Eyes and Ears Compete: Eye Tracking How Television News Viewers Read and Recall Pull Quote Graphics

Richards, Othello Lennox 01 May 2017 (has links)
This study applied dual processing theory, the theory of working memory, and the theory of cue summation to examine how the video and audio in a television news story interact with or against each other when the story uses pull quote graphics to convey key information to viewers. Using eye-tracking, the study produced visual depictions of exactly what viewers look at on the screen when the words in the reporter's voice track match the text in the pull quote graphic verbatim, when the reporter summarizes the text in the graphic, and when the reporter's voice track ignores the text in the pull quote. The study tested the effect on recall when viewers were presented with these three story conditions—high redundancy, medium redundancy, and low redundancy, respectively. Key findings included the following: first, that stories with low redundancy resulted in lower recall and memory sensitivity scores (a measure of memory strength) than pull quotes that the reporter either summarized or read verbatim on the air. Second, it was found that neither high-redundancy nor medium-redundancy stories were superior or inferior to the other when looking at the effect on recall and memory sensitivity. And finally, in high-, medium-, and low-redundancy conditions, subjects stated that they relied more on the reporter's narration than the pull quote to get information. The study states possible implications for news producers and reporters and suggests future research in the broadcast television news industry.
65

Coupled High-Order Finite Difference and Unstructured Finite Volume Methods for Earthquake Rupture Dynamics in Complex Geometries

O'Reilly, Ossian January 2011 (has links)
The linear elastodynamic two-dimensional anti-plane stress problem, where deformations occur in only one direction is considered for one sided non-planar faults. Fault dynamics are modeled using purely velocity dependent friction laws, and applied on boundaries with complex geometry. Summation-by-parts operators and energy estimates are used to couple a high-order finite difference method with an unstructured finite volume method. The unstructured finite volume method is used near the fault and the high-order finite difference method further away from the fault where no complex geometry is present. Boundary conditions are imposed weakly on characteristic form using the simultaneous approximation term technique, allowing explicit time integration to be used. Numerical computations are performed to verify the accuracy and time stability, of the method.
66

An Arcsin Limit Theorem of D-Optimal Designs for Weighted Polynomial Regression

Tsai, Jhong-Shin 10 June 2009 (has links)
Consider the D-optimal designs for the dth-degree polynomial regression model with a bounded and positive weight function on a compact interval. As the degree of the model goes to infinity, we show that the D-optimal design converges weakly to the arcsin distribution. If the weight function is equal to 1, we derive the formulae of the values of the D-criterion for five classes of designs including (i) uniform density design; (ii) arcsin density design; (iii) J_{1/2,1/2} density design; (iv) arcsin support design and (v) uniform support design. The comparison of D-efficiencies among these designs are investigated; besides, the asymptotic expansions and limits of their D-efficiencies are also given. It shows that the D-efficiency of the arcsin support design is the highest among the first four designs.
67

An NFFT based approach to the efficient computation of dipole-dipole interactions under different periodic boundary conditions

Nestler, Franziska 11 June 2015 (has links) (PDF)
We present an efficient method to compute the electrostatic fields, torques and forces in dipolar systems, which is based on the fast Fourier transform for nonequispaced data (NFFT). We consider 3d-periodic, 2d-periodic, 1d-periodic as well as 0d-periodic (open) boundary conditions. The method is based on the corresponding Ewald formulas, which immediately lead to an efficient algorithm only in the 3d-periodic case. In the other cases we apply the NFFT based fast summation in order to approximate the contributions of the nonperiodic dimensions in Fourier space. This is done by regularizing or periodizing the involved functions, which depend on the distances of the particles regarding the nonperiodic dimensions. The final algorithm enables a unified treatment of all types of periodic boundary conditions, for which only the precomputation step has to be adjusted.
68

Efficient Algorithms for Future Aircraft Design: Contributions to Aerodynamic Shape Optimization

Hicken, Jason 24 September 2009 (has links)
Advances in numerical optimization have raised the possibility that efficient and novel aircraft configurations may be ``discovered'' by an algorithm. To begin exploring this possibility, a fast and robust set of tools for aerodynamic shape optimization is developed. Parameterization and mesh-movement are integrated to accommodate large changes in the geometry. This integrated approach uses a coarse B-spline control grid to represent the geometry and move the computational mesh; consequently, the mesh-movement algorithm is two to three orders faster than a node-based linear elasticity approach, without compromising mesh quality. Aerodynamic analysis is performed using a flow solver for the Euler equations. The governing equations are discretized using summation-by-parts finite-difference operators and simultaneous approximation terms, which permit nonsmooth mesh continuity at block interfaces. The discretization results in a set of nonlinear algebraic equations, which are solved using an efficient parallel Newton-Krylov-Schur strategy. A gradient-based optimization algorithm is adopted. The gradient is evaluated using adjoint variables for the flow and mesh equations in a sequential approach. The flow adjoint equations are solved using a novel variant of the Krylov solver GCROT. This variant of GCROT is flexible to take advantage of non-stationary preconditioners and is shown to outperform restarted flexible GMRES. The aerodynamic optimizer is applied to several studies of induced-drag minimization. An elliptical lift distribution is recovered by varying spanwise twist, thereby validating the algorithm. Planform optimization based on the Euler equations produces a nonelliptical lift distribution, in contrast with the predictions of lifting-line theory. A study of spanwise vertical shape optimization confirms that a winglet-up configuration is more efficient than a winglet-down configuration. A split-tip geometry is used to explore nonlinear wake-wing interactions: the optimized split-tip demonstrates a significant reduction in induced drag relative to a single-tip wing. Finally, the optimal spanwise loading for a box-wing configuration is investigated.
69

Weak Boundary and Interface Procedures for Wave and Flow Problems

Abbas, Qaisar January 2011 (has links)
In this thesis, we have analyzed the accuracy and stability aspects of weak boundary and interface conditions (WBCs) for high order finite difference methods on Summations-By-Parts (SBP) form. The numerical technique has been applied to wave propagation and flow problems. The advantage of WBCs over strong boundary conditions is that stability of the numerical scheme can be proven. The boundary procedures in the advection-diffusion equation for a boundary layer problem is analyzed. By performing Navier-Stokes calculations, it is shown that most of the conclusions from the model problem carries over to the fully nonlinear case. The work was complemented to include the new idea of using WBCs on multiple grid points in a region, where the data is known, instead of at a single point. It was shown that we can achieve high accuracy, an increased rate of convergence to steady-state and non-reflecting boundary conditions by using this approach. Using the SBP technique and WBCs, we have worked out how to construct conservative and energy stable hybrid schemes for shocks using two different approaches. In the first method, we combine a high order finite difference scheme with a second order MUSCL scheme. In the second method, a procedure to locally change the order of accuracy of the finite difference schemes is developed. The main purpose is to obtain a higher order accurate scheme in smooth regions and a low order non-oscillatory scheme in the vicinity of shocks. Furthermore, we have analyzed the energy stability of the MUSCL scheme, by reformulating the scheme in the framework of SBP and artificial dissipation operators. It was found that many of the standard slope limiters in the MUSCL scheme do not lead to a negative semi-definite dissipation matrix, as required to get pointwise stability. Finally, high order simulations of shock diffracting over a convex wall with two facets were performed. The numerical study is done for a range of Reynolds numbers. By monitoring the velocities at the solid wall, it was shown that the computations were resolved in the boundary layer. Schlieren images from the computational results were obtained which displayed new interesting flow features.
70

(Des)construção da súmula cinculante n 4 do Supremo Tribunal Federal : elementos de conjuntura econômica e jurídica

Saulo Bosco Souza de Medeiros 26 October 2011 (has links)
Esta dissertação apresenta uma análise da jurisprudência do Supremo Tribunal Federal consubstanciada na súmula vinculante n. 4 sob uma perspectiva jurídico-econômica das relações de trabalho. A súmula vinculante n. 4 do Supremo Tribunal Federal declarou que, salvo casos previstos na Constituição, o salário mínimo não pode ser usado como indexador de base de cálculo de vantagem de servidor público ou de empregado, nem ser substituído por decisão judicial. Sob tal perspectiva, foi proibida a utilização do salário mínimo como base de cálculo do adicional de insalubridade, em confronto com a legislação trabalhista e com a jurisprudência até então sedimentada. Este estudo pretende refazer o processo de construção da jurisprudência constitucional vinculante em matéria trabalhista trazendo para o centro da discussão jurídica elementos de conjuntura econômica. Para tanto, fez-se a evolução do custo real do valor do salário mínimo brasileiro, a fim de possibilitar a identificação da sua influência nas decisões de investimento num cenário econômico neoliberal e globalizado. A partir deste dado, buscou-se apreender em que grau a jurisprudência tem sido utilizada como instrumento de segurança às relações econômicas e a eventual consequência frente à necessidade de garantir-se a melhoria da condição social dos trabalhadores

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