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Analyzing arterial blood flow by simulation of bifurcation treesOttosson, Johan January 2019 (has links)
The flow of blood in the human body is a very important component in un-derstanding a number of different ailments such as atherosclerosis and a falseaneurysm. In this thesis, we have utilized Poiseuille’s solution to Navier-Stokesequations with a Newtonian, incompressible fluid flowing laminar with zero ac-celeration in a pipe with non-flexible walls in order to study blood flow in anarterial tree. In order to study and simulate a larger arterial tree we have uti-lized a primitive building block, a bifurcation with one inlet and two outlets,joined together forming a tree. By prescribing an inlet flow and the pressureat every outlet at the bottom of the tree we have shown that we may solvethe system by fixed-point iteration, the Matlab functionfsolve, and Newton’smethod. This way of using primitive building blocks offers a flexible way to doanalysis as it makes it possible to easily change the shape of the tree as well asadding new building blocks such as a block that represents arteriosclerosis.
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Análise do efeito da precisão finita no algoritmo adaptativo sigmoidal / Analysis of the effect of finite precision on the sigmoidal adaptive algorithmFonseca, José de Ribamar Silva 16 February 2017 (has links)
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Previous issue date: 2017-02-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPQ) / The adaptive filtering is currently an important tool in the statistical processing
of signals, especially when it is necessary to process signals from environments with
unknown statistics varying with time. The adaptive filtering study was driven by the development
of the Least Mean Square algorithm (LMS) in 1960. Since then other adaptive
algorithms have come up with a better performance than LMS algorithm with respect to
misadjustment and convergence rate. Among them, the Sigmoidal algorithm (SA) which
showed superior to the LMS, for the convergence rate and the mismatch in their implementations
infinite precision. In hardware devices such as DSPs, microcontrollers and
FPGAs, adaptive algorithms are implemented in finite precision, in general, fixed point
arithmetic. When the adaptive filters are implemented in finite precision some effects
can affect their performance. Ultimately lead to divergence due to quantization errors
specified in the approximation process of the variables involved in the adaptive processing
of their original values. Thus, this article aims to analyze the performance of the adaptive
algorithm Sigmoidal (SA) in finite precision when implemented using fixed-point arithmetic.
In particular, the analysis of its performance curve and mismatch, comparing them
in different word lengths (number of bits). The results presented in this article proposes
a series of Taylor Ln gradient of cost function (cosh αe) algorithm SA for implementation
in finite precision. We analyze its performance curve for different lengths of words. It
shows that the algorithm is stable in its performance compared to convergence to different
lengths of words, and that the increase in mismatch level at steady state is sensitive or
afected by the quantization of the variables involved in the calculations of this algorithm. / A filtragem adaptativa constitui atualmente uma ferramenta importante no
processamento estatístico de sinais, especialmente quando é necessário processar sinais
provenientes de ambientes com estatísticas desconhecidas que variam com o tempo. O estudo
de filtragem adaptativa foi impulsionado com o desenvolvimento do algoritmo Least
Mean Square (LMS) em 1960. Desde então outros algoritmos adaptativos têm surgido
com um desempenho superior ao algoritmo LMS em relação ao desajuste e à taxa de
convergência. Entre eles, o algoritmo Sigmoidal (SA) que se apresentou superior ao LMS,
em relação a taxa de convergência e o desajuste em suas implementações na forma analógica.
Nos dispositivos de hardware, tais como DSPs, Microcontroladores e FPGAs, os
algoritmos adaptativos são implementados na forma digital, onde a precisão é finita, em
geral, com aritmética de ponto fixo. Quando os filtros adaptativos são implementados
em precisão finita alguns efeitos podem afetar o seu desempenho. Em última análise,
levar à divergência devido aos erros de quantização especificados no processo de aproximação
dos valores das variáveis envolvidas no processamento adaptativo de seus valores
originais. Assim, este trabalho propõe analisar o desempenho do algoritmo adaptativo
Sigmoidal (SA) em precisão nita, quando implementado utilizando aritmética de ponto
xo. Em particular, a análise de sua curva de desempenho e o desajuste, comparando-os
em diferentes comprimentos de palavras (número de bits). Os resultados apresentados
neste trabalho propõe uma aproximação em série de Taylor do gradiente da função de
custo Ln(cosh αe) do algoritmo SA para implementação em precisão finita. Analisamos
a sua curva de desempenho para diferentes comprimentos de palavras. Mostra-se que
o algoritmo apresenta estabilidade em seu desempenho em relação à convergência, para
diferentes comprimentos de palavras, e que o aumento no nível do desajuste em estado estacionário
é sensível ou influenciado pela quantização dos valores das variáveis envolvidas
nos cálculos desse algoritmo.
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A Study of Abelian Dualities in 2+1 DimensionsJing, Xiaoyi January 2019 (has links)
It is well-known that in 2 + 1 dimensions the flux attachment transmutes the statistics of a particle.The aim of this master thesis is to study the dualities between bosons and fermions induced by Abeliantopological gauge fields in 2 + 1 dimensions. Chapter 1 and 2 are reviews of known results about thepath integral quantization of Chern-Simons theory and the regularization of the fermionic path integral.In the following chapters, we will derive the statistical transmutation and various Abelian dualities in2 + 1 dimensions.
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Deformabilidade sobre S^1 a livre de ponto fixo para auto-aplicações de T-fibrados e Reidemeister sobre S^1 / Deformability over S^1 of self-maps of T-bundles into a fixed point free map and Reidemeister over S^1Prado, Gustavo de Lima 25 March 2010 (has links)
Classificação das auto-aplicações de fibrados, com fibra toro, que preservam fibra sobre o círculo, com a propriedade de poderem ser deformadas sobre o círculo a uma aplicação livre de ponto fixo. Ainda, investigamos a relação entre o número de Reidemeister sobre o círculo e a propriedade acima / Classification of all fiber-preserving self-maps of torus bundles over the circle by the property of being able to deform them over the circle into a fixed point free map by a fiberwise homotopy over the circle. We also investigate the relationship between Reidemeister number over the circle and the property above
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A Lefschetz fixed point theorem for manifolds with conical singularitiesNazaikinskii, Vladimir, Schulze, Bert-Wolfgang, Sternin, Boris, Shatalov, Victor January 1997 (has links)
We establish an Atiyah-Bott-Lefschetz formula for elliptic operators on
manifolds with conical singular points.
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A semiclassical quantization on manifolds with singularities and the Lefschetz Formula for Elliptic OperatorsSchulze, Bert-Wolfgang, Nazaikinskii, Vladimir, Sternin, Boris January 1998 (has links)
For general endomorphisms of elliptic complexes on manifolds with conical singularities, the semiclassical asymptotics of the Atiyah-Bott-Lefschetz number is calculated in terms of fixed points of the corresponding canonical transformation of the symplectic space.
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Dynamical Systems Over Finite GroupsBadar, Muhammad January 2012 (has links)
In this thesis, the dynamical system is used as a function on afinite group, to show how states change. We investigate the'numberof cycles' and 'length of cycle' under finite groups. Using grouptheory, fixed point, periodic points and some examples, formulas tofind 'number of cycles' and 'length of cycle' are derived. Theexamples used are on finite cyclic group Z_6 with respectto binary operation '+'. Generalization using finite groups ismade. At the end, I compared the dynamical system over finite cyclic groups with the finite non-cyclic groups and then prove the general formulas to find 'number of cycles' and 'length of cycle' for both cyclic and non-cyclic groups.
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Convergence Analysis for Inertial Krasnoselskii-Mann Type Iterative AlgorithmsHuang, Wei-Shiou 16 February 2011 (has links)
We consider the problem of finding a common fixed point of an infinite family ${T_n}$
of nonlinear self-mappings of a closed convex subset $C$ of a real Hilbert space $H$. Namely,
we want to find a point $x$ with the property (assuming such common fixed points exist):
[
xin igcap_{n=1}^infty ext{Fix}(T_n).
]
We will use the Krasnoselskii-Mann (KM) Type inertial iterative algorithms of the form
$$ x_{n+1} = ((1-alpha_n)I+alpha_nT_n)y_n,quad
y_n = x_n + eta_n(x_n-x_{n-1}).eqno(*)$$
We discuss the convergence properties of the sequence ${x_n}$ generated by this algorithm (*).
In particular, we prove that ${x_n}$ converges weakly to a common fixed point of the family
${T_n}$ under certain conditions imposed on the sequences ${alpha_n}$ and ${eta_n}$.
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Existence of Solutions for Boundary Value Problems with Nonlinear DelayLuo, Yu-chen 05 July 2007 (has links)
In this thesis, we consider the following delay boundary value problem
egin{eqnarray*}(BVP)left{begin{array}{l}y'(t)+q(t)f(t,y(sigma(t)))=0, tin(0,1)/{ au},
y(t)=xi(t), tin[- au_{0},0],
y(1)=0,end{array}
right.
end{eqnarray*}, where the functions f and q satisfy certain conditions; $sigma(t)leq t$ is a nonlinear real valued
continuous function.
We use two different methods to establish some existence criteria for the solution of problem
(BVP). We generalize the delay term to a nonlinear function and obtain more general and
supplementary results for the known ones about linear delay term due to Agarwal and O¡¦Regan
[1] and Jiang and Xu [5].
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On Finite Groups Admitting A Fixed Point Free Abelian Operator Group Whose Order Is A Product Of Three PrimesMut Sagdicoglu, Oznur 01 August 2009 (has links) (PDF)
A long-standing conjecture states that if A is a finite group acting fixed point freely on a
finite solvable group G of order coprime to jAj, then the Fitting length of G is bounded by
the length of the longest chain of subgroups of A. If A is nilpotent, it is expected that the
conjecture is true without the coprimeness condition. We prove that the conjecture without
the coprimeness condition is true when A is a cyclic group whose order is a product of three
primes which are coprime to 6 and the Sylow 2-subgroups of G are abelian. We also prove
that the conjecture without the coprimeness condition is true when A is an abelian group
whose order is a product of three primes which are coprime to 6 and jGj is odd.
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