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1
Comaga, Kerim. "MSc Architecture." Thesis, KTH, Arkitektur, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-298483.
Full textAbstract:
This project has revolved around how to expand Stockholm in socially sustainable way. As is the case with many other cities in the world, inspired by modernist ideals, expansion during the 1900: s have shaped Stockholm into an archipelago of islands with mostly homogenous housing types that exist within an urban structure of centre and periphery. The Stockholm City Council is trying counter this situation by expanding the city centre into eight new regional cores by densifying a few chosen areas. This is done by conforming to old traditions of placing existing housing types and public spaces in a similar way as before. How do you go one step further in decentralizing Stockholm and breaking away from these traditions? The idea for this project is then to create an alternative typology that will be spread out homogeneously throughout the regional cores and that will grow organically as new needs emerge over time. The typology itself is simply a building scaffolding, a 6x6x7 steel grid, that will act as a tool for urban planning and host creation and expansion of new housing and public situations that together aim to constitute new parts of an alternative type of growing city centre.
2
Weber, Sérgio. "ASPE/MSC." Florianópolis, SC, 2005. http://repositorio.ufsc.br/handle/123456789/102368.
Full textAbstract:
Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico. Programa de Pós-Graduação em Ciência da Computação<br>Made available in DSpace on 2013-07-16T00:46:12Z (GMT). No. of bitstreams: 1
224905.pdf: 5536445 bytes, checksum: 9c37dced0f425adf455a3f6d0fa8b466 (MD5)<br>Segundo dados do ministério da ciência e tecnologia (MCT), o mercado brasileiro na área de software é composto predominantemente por micro e pequenas empresas (MPEs), cujos processos são executados geralmente de modo informal, improvisado e com pouca visibilidade. Esse cenário gera uma série de dificuldades a essas organizações, tornando-as enfraquecidas para competir no mercado e crescerem. Uma alternativa para a mudança desse quadro é o investimento em estabelecimento de processos sistemáticos de software, já que a qualidade dos produtos desenvolvidos são altamente influenciados pelos seus processos de produção.
Nesse contexto, o presente trabalho propõe e avalia a abordagem ASPE/MSC (Approach for Software Process Establishment in Micro and Small Companies), cujo objetivo é estabelecer processos de software em MPEs, considerando suas características e limitações. Seu desenvolvimento está baseado em estudos sobre estabelecimento de processos de software, na adaptação de técnicas e abordagens existentes nessa área de pesquisa e na experiência em modelagem de processos de software, obtida pelo LQPS - Laboratório de Qualidade e Produtividade de Software da UNIVALI e pelo Grupo de Qualidade de Software do centro GeNESS. A avaliação da abordagem é realizada por meio de dois estudos de caso, executados em duas pequenas empresas de software em Florianópolis/SC.
Os principais resultados do trabalho são a abordagem ASPE/MSC e as experiências obtidas com a execução dos estudos de caso, que incluem dados qualitativos e quantitativos. A abordagem ASPE/MSC está documentada na forma de um guia, que descreve detalhadamente as atividades que a compõem, os papéis envolvidos na execução das respectivas atividades, templates de documentos para auxiliar na sua aplicação e diretrizes para sua execução num contexto real.
A perspectiva do trabalho é auxiliar micro e pequenas empresas de software a se fortalecerem no mercado, através da melhoria contínua dos seus processos. Com isso, espera-se que, MPEs possam alcançar gradativamente patamares mais elevados de qualidade, produtividade e competitividade.
3
Jentsch, Lothar, and David Natroshvili. "Three-dimensional mathematical Problems of thermoelasticity of anisotropic Bodies." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800967.
Full textAbstract:
CHAPTER I. Basic Equations. Fundamental Matrices. Thermo-Radiation Conditions
1. Basic differential equations of thermoelasticity theory
2. Fundamental matrices
3. Thermo-radiating conditions. Somigliana type integral representations
CHAPTER II. Formulation of Boundary Value and Interface Problems
4. Functional spaces
5. Formulation of basic and mixed BVPs
6. Formulation of crack type problems
7. Formulation of basic and mixed interface problems
CHAPTER III. Uniqueness Theorems
8. Uniqueness theorems in pseudo-oscillation problems
9. Uniqueness theorems in steady state oscillation problems
CHAPTER IV. Potentials and Boundary Integral Operators
10. Thermoelastic steady state oscillation potentials
11. Pseudo-oscillation potentials
CHAPTER V. Regular Boundary Value and Interface Problems
12. Basic BVPs of pseudo-oscillations
13. Basic exterior BVPs of steady state oscillations
14. Basic interface problems of pseudo-oscillations
15. Basic interface problems of steady state oscillations
CHAPTER VI. Mixed and Crack Type Problems
16. Basic mixed BVPs
17. Crack type problems
18. Mixed interface problems of steady state oscillations
19. Mixed interface problems of pseudo-oscillations
4
Jentsch, L., D. Natroshvili, and I. Sigua. "Mixed Interface Problems of Thermoelastic Pseudo-Oscillations." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801150.
Full textAbstract:
Three-dimensional basic and mixed interface problems of the mathematical
theory of thermoelastic pseudo-oscillations are considered for piecewise homogeneous
anisotropic bodies. Applying the method of boundary potentials and the theory of
pseudodifferential equations existence and uniqueness theorems of solutions are proved
in the space of regular functions C^(k+ alpha) and in the Bessel-potential (H^(s)_(p))
and Besov (B^(s)_(p,q)) spaces. In addition to the classical regularity results
for solutions to the basic interface problems, it is shown that in the mixed interface
problems the displacement vector and the temperature are Hölder continuous with
exponent 0<alpha<1/2.
5
Jentsch, L., and D. Natroshvili. "Interaction between Thermoelastic and Scalar Oscillation Fields (general anisotropic case)." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801162.
Full textAbstract:
Three-dimensional mathematical problems of the interaction between thermoelastic
and scalar oscillation fields are considered in a general anisotropic case. An elastic
structure is assumed to be a bounded homogeneous anisortopic body occupying domain
$\Omega^+\sub\R^3$ , where the thermoelastic field is defined, while in the
physically anisotropic unbounded exterior domain $\Omega^-=\R^3\\ \overline{\Omega^+}$
there is defined the scalar field. These two fields
satisfy the differential equations of steady state oscillations in the corresponding
domains along with the transmission conditions of special type on the interface
$\delta\Omega^{+-}$. Uniqueness and existence theorems, for the non-resonance case, are proved
by the reduction of the original interface problems to equivalent systems of boundary
pseudodifferential equations ($\Psi DEs$) . The invertibility of the corresponding
matrix pseudodifferential operators ($\Psi DO$) in appropriate functional spaces is
shown on the basis of generalized Sommerfeld-Kupradze type thermoradiation conditions
for anisotropic bodies. In the resonance case, the co-kernels of the $\Psi DOs$ are
analysed and the efficent conditions of solvability of the transmission problems
are established.
6
Jentsch, L., and D. Natroshvili. "Thermoelastic Oscillations of Anisotropic Bodies." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800871.
Full textAbstract:
The generalized radiation conditions at infinity of Sommerfeld-Kupradze type are established in the theory of thermoelasticity of anisotropic bodies. Applying the potential method and the theory of pseudodifferential equations on manifolds the uniqueness and existence theorems of solutions to the basic three-dimensional exterior boundary value problems are proved and representation formulas of solutions by potential type integrals are obtained.
7
Jung, M., and U. Rüde. "Implicit extrapolation methods for multilevel finite element computations." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800516.
Full textAbstract:
Extrapolation methods for the solution of partial differential equations are commonly based on the existence of error expansions for the approximate solution. Implicit extrapolation, in the contrast, is based on applying extrapolation indirectly, by using it on quantities like the residual. In the context of multigrid methods, a special technique of this type is known as \034 -extrapolation. For finite element systems this algorithm can be shown to be equivalent to higher order finite elements. The analysis is local and does not use global expansions, so that the implicit extrapolation technique may be used on unstructured meshes and in cases where the solution fails to be globally smooth. Furthermore, the natural multilevel structure can be used to construct efficient multigrid and multilevel preconditioning techniques. The effectivity of the method is demonstrated for heat conduction problems and problems from elasticity theory.
8
Natroshvili, David, and Shota Zazashvili. "The Interface Crack Problem for Anisotropic Bodies." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800979.
Full textAbstract:
The two-dimensional interface crack problem is investigated for anisotropic bodies in the Comninou formulation. It is established that, as in the isotropic case, properly incorporating contact zones at the crack tips avoids contradictions connected with the oscillating asymptotic behaviour of physical and mechanical characteristics leading to the overlapping of material. Applying the special integral representation formulae for the displacement field the problem in question is reduced to the scalar singular integral equation with the index equal to -1. The analysis of this equation is given. The comparison with the results of previous authors shows that the integral equations corresponding to the interface crack problems in the anisotropic and isotropic cases are actually the same from the point of view of the theoretical and numerical analysis.
9
Coquery, Nicolas [Verfasser]. "Intrahippocampal transplantation of MSC and MSC-expressing BDNF in Rat Models of Depression-like Behaviour / Nicolas Coquery." Berlin : Medizinische Fakultät Charité - Universitätsmedizin Berlin, 2009. http://d-nb.info/1023665360/34.
Full text
10
Leonard, Martha Maria. "A description of final year nursing students' ability to recognize abnormal vital signs recordings and clinical decision-making process." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/6663.
Full textAbstract:
Includes abstract.<br>Includes bibliographical references.<br>The aim of this study was to determine whether final year nursing students can recognize and respond to abnormal vital sign recordings, and to analyse their clinical decision-making processes.
11
Pester, M. "Grafik-Ausgabe vom Parallelrechner für 2D-Gebiete." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800602.
Full textAbstract:
The paper mainly describes the user interface of some graphical
visualization tools for parallel finite element applications in
2D (layer problems, deformation problems, fluid dynamics). There
are presented some examples of various methods to display the
numerical results.
12
Meyer, M. "Grafik-Ausgabe vom Parallelrechner für 3D-Gebiete." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800669.
Full textAbstract:
The paper describes a method for Visualization of computational results in parallel finite element applications for 3D problems. The visualization itself is done on a workstation using a post- processing tool based on GRAPE, which interacts with the parallel program to obtain data.
13
Apel, T., G. Haase, A. Meyer, and M. Pester. "Parallel solution of finite element equation systems: efficient inter-processor communication." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800670.
Full textAbstract:
This paper deals with the application of domain decomposition methods for the parallel solution of boundary value problems for partial differential equations over a domain $Omegabset R^d$, $d=2,3$. The attention is focused on the conception of efficient communication routines for the data exchange which is necessary for example in the preconditioned cg-algorithm for solving the resulting system of algebraic equations. The paper describes the data structure, different algorithms, and computational tests.
14
Ivanov, S. A., and V. G. Korneev. "On the preconditioning in the domain decomposition technique for the p-version finite element method. Part I." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800856.
Full textAbstract:
Abstract P-version finite element method for the second order elliptic equation in an arbitrary sufficiently smooth domain is studied in the frame of DD method. Two types square reference elements are used with the products of the integrated Legendre's polynomials for the coordinate functions. There are considered the estimates for the condition numbers, preconditioning of the problems arising on subdomains and the Schur complement, the derivation of the DD preconditioner. For the result we obtain the DD preconditioner to which corresponds the generalized condition number of order (logp )2 . The paper consists of two parts. In part I there are given some preliminary re- sults for 1D case, condition number estimates and some inequalities for 2D reference element.
15
Reichel, U. "Partitionierung von Finite-Elemente-Netzen." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801107.
Full textAbstract:
The realization of the finite element method on parallel computers
is usually based on a domain decomposition approach. This paper is
concerned with the problem of finding an optimal decomposition and an
appropriate mapping of the subdomains to the processors. The quality
of this partitioning is measured in several metrics but it is also
expressed in the computing time for solving specific systems of
finite element equations.
The software environment is first described. In particular, the data
structure and the accumulation algorithm are introduced. Then
several partitioning algorithms are compared. Spectral bisection was
used with different modifications including Kernighan-Lin refinement,
post-processing techniques and terminal propagation. The final
recommendations should give good decompositions for all finite
element codes which are based on principles similar to ours.
The paper is a shortened English version of Preprint SFB393/96-18
(Uwe Reichel: Partitionierung von Finite-Elemente-Netzen), SFB 393,
TU Chemnitz-Zwickau, December 1996. To be selfcontained, some material
of Preprint SPC95_5 (see below) is included. The paper appeared as
Preprint SFB393/96-18a, SFB 393, TU Chemnitz-Zwickau, January 1997.
16
Grabitz, Martin. "Zur Konstruktion einfacher Charaktere und der Fortsetzungen ihrer Heisenbergdarstellungen für lokale zentral-einfache Algebren." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2000. http://dx.doi.org/10.18452/14482.
Full textAbstract:
In dieser Dissertationsschrift soll erkl{\"a}rt werden, wie auf der Grundlage von einfachen Strata, wie sie in einer gemeinsamen Arbeit mit Broussous \cite{BG} betrachtet wurden, einfache Charaktere f{\"u}r lokale einfache Algebren konstruiert werden k{\"o}nnen, wobei die Konstruktion den Vorbildern von Bushnell und Kutzko im zerfallenden Fall \cite{BK1} und von Zink \cite{Z7} im Falle eines Schiefk{\"o}rpers folgt. Der Begriff des einfachen Charakters geht auf die Arbeit \cite{BK1} zur{\"u}ck und bezeichnet eine ausgezeichnete Auswahl von Heisenbergcharakteren, die zu einem stabilen Darstellungsfilter geh{\"o}ren, der gem{\"a}{ss} \cite{Z2}(Hauptsatz 1.4) einem Darstellungsfilter zugeordnet wird, der zu einer absteigenden Normalreihe $$1+\R\supset1+\R^2\supset\ldots$$ geh{\"o}rt, wobei $\R$ das Jacobsonradikal einer erblichen Ordnung bezeichnet. Wir werden hier nur von Hauptordnungen ausgehen, d.h. von dem Fall, da{ss} $\R$ und seine Potenzen gebrochene Hauptideale sind. Diese Vorgehensweise und auch die besondere Auswahl der Heisenbergcharaktere in Form von einfachen Charakteren, wird durch die Konstruktion im Falle eines Schiefk{\"o}rpers \cite{Z7} und durch den abstrakten Matchingsatz \cite{BDKV} gerechtfertigt. Im Falle eines lokalen zentralen Schiefk{\"o}rpers ist n{\"a}mlich der Bewertungsring die einzige erbliche Ordnung und die einfachen Charaktere sind alle Heisenbergcharaktere die zu einem stabilen Darstellungsfilter geh{\"o}ren, der gem{\"a}{ss} \cite{Z2}(Hauptsatz 1.4) einem Darstellungsfilter, der zur absteigenden Normalreihe $$1+\pin_D\supset1+\pin_D^2\supset\ldots$$ geh{\"o}rt, zugeordnet wird, wobei $\pin_D$ das Bewertungsideal des Schiefk{\"o}rpers $D$ bezeichnet. Der abstrakte Matchingsatz liefert nun die Existenz einer Bijektion zwischen den irreduziblen glatten Darstellungen der multiplikativen Gruppe des lokalen zentralen Schiefk{\"o}rpers $D$ und den irreduziblen quadratintegrierbaren glatten Darstellungen einer beliebigen anderen lokalen zentraleinfachen Algebra vom selben reduzierten Grad {\"u}ber demselben nicht-archimedischen Grundk{\"o}rper $F$, welche den Charakter einer Darstellung in dem Sinne erh{\"a}lt, da{ss} die Charakterwerte auf den Konjugationsklassen elliptischer Elemente der verschiedenen Algebren, welche mithilfe ihrer Minimalpolynome identifiziert werden k{\"o}nnen, bis auf ein Vorzeichen {\"u}bereinstimmen. Wir werden hier kanonische Bijektionen zwischen den einfachen Charakteren f{\"u}r verschiedene zentraleinfache Algebren vom selben reduzierten Grad {\"u}ber demselben Grundk{\"o}rper angeben, von denen wir erwarten, da{ss} sie mit der Abbildung des abstrakten Matchingsatzes vertr{\"a}glich sind. Das dieses in der Tat der Fall ist, wurde bisher nur in einfachen F{\"a}llen wie \cite{He} und \cite{BH2} gezeigt, jedoch wurde in der Arbeit \cite{Z4} bereits mithilfe der Konstruktionen von \cite{Z7} und \cite{BK3} eine Bijektion zwischen den irreduziblen glatten Darstellungen der multiplikativen Gruppe des lokalen zentralen Schiefk{\"o}rpers $D$ vom Index $N$ {\"u}ber einem Grundk{\"o}rper $F$ und den irreduziblen essentiell quadratintegrierbaren glatten Darstellungen von $Gl_N(F)$ konstruiert, welche den Artinf{\"u}hrer und den formalen Grad einer Darstellung erh{\"a}lt. Da die Abbildung des abstrakten Matchingsatzes dieselben Forderungen erf{\"u}llt, kommt dies der gew{\"u}nschten Vertr{\"a}glichkeit schon sehr nahe und wir erf{\"u}llen mit unserer Konstruktion insbesondere die in der Arbeit \cite{Z4} gemachte Forderung die dort im Bezug auf die einfachen Charaktere getroffen Auswahlen noch unabh{\"a}ngiger von den jeweiligen Algebren zu gestalten. Die hier getroffene Auswahl wird durch die Verwendung sogenannter spezieller approximierender Folgen getroffen, welche sich aus einer Verallgemeinerung der in \cite{BG} gemachten {\"U}berlegungen ergeben. Im Anschlu{ss} an die Konstruktion und den Vergleich einfacher Charaktere werden wir in einer gro{ss}en Anzahl von F{\"a}llen zeigen, da{ss} sich die Heisenbergdarstellungen, die wir zu den einfachen Charakteren erhalten, in kanonischer Weise fortsetzen lassen und wir erwarten von diesen Fortsetzungen, da{ss} sie analoge Eigenschaften besitzen, wie die sogenannten ``$\beta$-Fortsetzungen'' von \cite{BK1}(5.2.1) im zerfallenden Fall. Damit k{\"o}nnen wir in diesen F{\"a}llen eine Liste von hypothetischen einfachen Typen angeben, von denen wir vermuten, da{ss} sie alle Bernsteinkomponenten parametrisieren, welche irreduzible essentiell quadratintegrierbare Darstellungen enthalten. Insbesondere vermuten wir, da{ss} sich die supercuspidalen Darstellungen mittels kompakter Induktion aus Fortsetzungen solcher einfacher Typen auf eine kompakt modulo Zentrum Untergruppe gewinnen lassen. Um die Vollst{\"a}ndigkeit dieser Konstruktion zu demonstrieren, h{\"a}tten wir allerdings noch die Eigenschaft ``Verkettung impliziert Konjugation'' zu zeigen, welche wir ebenfalls auf eine Folgearbeit verschieben m{\"u}ssen. Beabsichtig w{\"a}re dann ein Vollst{\"a}ndigkeitsbeweis mit dem abstrakten Matchingsatz wie bei L. Corwin \cite{Co} oder in \cite{Z4}. Wir weisen hier nur in Spezialf{\"a}llen nach, dass die Typendarstellungen, welche wir hier angegeben haben, tats{\"a}chlich Typen im Sinne von \cite{BK4}(4.1)(4.2) sind. Insbesondere sind es auch unsere Berechnungen in der Arbeit \cite{GSZ}, welche dem von uns im Geiste von \cite{Z7} und \cite{BK1} gemachten Ans{\"a}tzen hohe Evidenz geben.<br>In this thesis, we try to explain how simple characters for arbitrary central simple algebras over a non-archimedian local field $F$ can be constructed. Moreover, we introduce a kind of matching of simple characters between different algebras of fixed reduced degree. If the index of the algebra $A$ is odd or $A=M_l(D)$, where $l$ is an arbitrary prime number and $D$ a central division algebra over $F$, we can extend the Heisenberg representations associated to the simple characters to level-0 and obtain a hypothetical list of simple types. For $A=M_l(D)$ and if the residual field of $F$ is not the field with two elements, we can proof that all so-called maximal simple types in our list are simple types in the sense of \cite{BK4} and their extensions to their stabelizers induce supercupidal representations of $G_l(D)$. Using the the heuristical relation via the abstract matching theorem of \cite{BDKV} to the cases of a division algebra due to \cite{Z5} and to the split case due to \cite{BK1}, we conjecture that all supercuspidal representations of $Gl_l(D)$ can be obtained by this way.
17
Pester, M., and S. Rjasanow. "A parallel preconditioned iterative realization of the panel method in 3D." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800562.
Full textAbstract:
The parallel version of precondition iterative techniques is
developed for matrices arising from the panel boundary element
method for three-dimensional simple connected domains with
Dirichlet boundary conditions. Results were obtained on an
nCUBE-2 parallel computer showing that iterative solution methods
are very well suited also in three-dimensional case for
implementation on a MIMD computer and that they are much more
efficient than usual direct solution techniques.
18
Apel, Th. "Interpolation of non-smooth functions on anisotropic finite element meshes." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801341.
Full textAbstract:
In this paper, several modifications of the quasi-interpolation operator
of Scott and Zhang (Math. Comp. 54(1990)190, 483--493) are discussed.
The modified operators are defined for non-smooth functions and are suited
for the application on anisotropic meshes. The anisotropy of the elements
is reflected in the local stability and approximation error estimates.
As an application, an example is considered where anisotropic finite element
meshes are appropriate, namely the Poisson problem in domains with edges.
19
Apel, T., and S. Nicaise. "Elliptic problems in domains with edges: anisotropic regularity and anisotropic finite element meshes." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800553.
Full textAbstract:
This paper is concerned with the anisotropic singular behaviour of the solution of elliptic boundary value problems near edges. The paper deals first with the description of the analytic properties of the solution in newly defined, anisotropically weighted Sobolev spaces. The finite element method with anisotropic, graded meshes and piecewise linear shape functions is then investigated for such problems; the schemes exhibit optimal convergence rates with decreasing mesh size. For the proof, new local interpolation error estimates in anisotropically weighted spaces are derived. Moreover, it is shown that the condition number of the stiffness matrix is not affected by the mesh grading. Finally, a numerical experiment is described, that shows a good agreement of the calculated approximation orders with the theoretically predicted ones.
20
Gowthaman, Rahul, and Suhail Jagwani. "Advanced bushing script program in MSC ADAMS." Thesis, KTH, Fordonsdynamik, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-243489.
Full textAbstract:
The thesis focuses on investigating and optimizing a bushing script implemented as a tool in MSC ADAMS/Car. The study provides an insight on the representation of a rubber bushing and identify parameters which can be used to define the properties of a bushing in a simulation environment such as ADAMS/Car. The tool being studied here can be used to implement different kind of bushings such as a hydro bushing and a general rubber bushing, but optimization was implemented for the rubber bushing only. With an increasing reliance on Computer Aided Engineering (CAE) tools in the designing process, it is necessary that the vehicle behaviour can be predicted without relying on physical testing. CAE tools reduces the need of prototypes and provides a faster approach to designing vehicles. MSC ADAMS/Car is one such tool, which has been used here to predict the vehicle dynamic behaviour, which will influence the ride, handling and comfort characteristics of the vehicle. Rubber bushings, which have been studied here, have a significant contribution to the overall stiffness of the vehicle and as such, it is imperative that the tool being used here, is accurate and makes the designing process easy. The rubber bushing can be imagined to be a combination of a non-linear elastic spring, a frequency dependent Maxwell component and an amplitude dependent frictional element. In order to ease the design of the bushing properties, a reduced number of input properties are used to calculate the bushing properties internally. While trying to validate the force hysteresis loop obtained through the model with the measured data, it was seen that the accuracy was quite poor for the model when loading it with dynamic loads corresponding to amplitudes of0.2 mm and lower. The quasi-static loading and dynamic loading above 0.2 mm is shown to have a satisfactory accuracy when compared to the measured data.
21
Chu, D., and V. Mehrmann. "Minimum Norm Regularization of Descriptor Systems by Output Feedback." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801177.
Full textAbstract:
We study the regularization problem for linear, constant coefficient descriptor
systems $E x^. = AX + Bu, y_1 = Cx, y_2=\Gamma x^.$ by proportional and derivative
mixed output feedback. Necessary and sufficient conditions are given, which guarantee
that there exist output feedbacks such that the closed-loop system is regular, has
index at most one and $E +BG\Gamma$ has
a desired rank, i.e. there is a desired number of differential and algebraic equations.
To resolve the freedom in the choice of the feedback matrices we then discuss how
to obtain the desired regularizing feedback of minimum norm and show that this approach
leads to useful results in the sense of robustness only if the rank of E is
decreased. Numerical procedures are derived to construct the desired feedbacks gains.
These numerical procedures are based on orthogonal matrix transformations which
can be implemented in a numerically stable way.
22
Penzl, T. "Numerical solution of generalized Lyapunov equations." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800893.
Full textAbstract:
Two efficient methods for solving generalized Lyapunov equations and their implementations in FORTRAN 77 are presented. The first one is a generalization of the Bartels--Stewart method and the second is an extension of Hammarling's method to generalized Lyapunov equations. Our LAPACK based subroutines are implemented in a quite flexible way. They can handle the transposed equations and provide scaling to avoid overflow in the solution. Moreover, the Bartels--Stewart subroutine offers the optional estimation of the separation and the reciprocal condition number. A brief description of both algorithms is given. The performance of the software is demonstrated by numerical experiments.
23
Pester, M. "On-line visualization in parallel computations." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801143.
Full textAbstract:
The investigation of new parallel algorithms for MIMD computers
requires some postprocessing facilities for quickly evaluating
the behavior of those algorithms We present two kinds of
visualization tool implementations for 2D and 3D finite element
applications to be used on a parallel computer and a host
workstation.
24
Kunert, G. "Error Estimation for Anisotropic Tetrahedral and Triangular Finite Element Meshes." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801440.
Full textAbstract:
Some boundary value problems yield anisotropic solutions, e.g. solutions
with boundary layers. If such problems are to be solved with the finite
element method (FEM), anisotropically refined meshes can be
advantageous.
In order to construct these meshes or to control the error
one aims at reliable error estimators.
For \emph{isotropic} meshes many estimators are known, but they either fail
when used on \emph{anisotropic} meshes, or they were not applied yet.
For rectangular (or cuboidal) anisotropic meshes a modified
error estimator had already been found.
We are investigating error estimators on anisotropic tetrahedral or
triangular meshes because such grids offer greater geometrical flexibility.
For the Poisson equation a residual error estimator, a local Dirichlet problem
error estimator, and an $L_2$ error estimator are derived, respectively.
Additionally a residual error estimator is presented for a singularly
perturbed reaction diffusion equation.
It is important that the anisotropic mesh corresponds to the anisotropic
solution. Provided that a certain condition is satisfied, we have proven
that all estimators bound the error reliably.
25
Mehrmann, V. "A step towards a unified treatment of continuous and discrete time control problems." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800581.
Full textAbstract:
In this paper introduce new approach for
unified theory for continuous and discrete time
(optimal) control problems based on the
generalized Cayley transformation. We also relate
the associated discrete and continuous generalized
algebraic Riccati equations. We demonstrate the
potential of this new approach proving new
result for discrete algebraic Riccati equations.
But we also discuss where this new approach as
well as all other approaches still is
non-satisfactory. We explain a discrepancy
observed between the discrete and continuous
cse and show that this discrepancy is partly due
to the consideration of the wrong analogues. We
also present an idea for a metatheorem that
relates general theorems for discrete and
continuous control problems.
26
Grabowsky, L., Th Ermer, and J. Werner. "Nutzung von MPI für parallele FEM-Systeme." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801365.
Full textAbstract:
Der Standard des Message Passing Interfaces (MPI) stellt dem Entwickler paralleler Anwendungen ein mächtiges Werkzeug zur Verfügung, seine Softwa- re effizient und weitgehend unabhängig von Details des parallelen Systems zu entwerfen.
Im Rahmen einer Projektarbeit erfolgte die Umstellung der Kommunikationsbibliothek eines bestehenden FEM-Programmes auf den MPI-Mechanismus. Die Ergebnisse werden in der hier gegebenen Beschreibung der Cubecom-Implementierung zusammengefasst.
In einem zweiten Teil dieser Arbeit wird untersucht, auf welchem Wege mit der in MPI verfügbaren Funktionalität auch die Koppelrandkommunikation mit einem einheitlichen und effizienten Verfahren durchgeführt werden kann.
Sowohl fuer die Basisimplementierung als auch die MPI-basierte Koppelrandkommunikation wird die Effizienz untersucht und ein Ausblick auf weitere Anwendungsmoeglichkeiten gegeben.
27
Grabowsky, L. "MPI-basierte Koppelrandkommunikation und Einfluß der Partitionierung im 3D-Fall." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801453.
Full textAbstract:
In der vorliegenden Arbeit wird die Anwendung eines bereits im 2D-Fall benutzten Mechanismus zur MPI-basierten Koppelrandkommunikation auf das 3D-FEM-System SPC PMPo-3D beschrieben. Insbesondere soll der Einfluss der Partitionierung auf die Laufzeit im Vergleich mit den Resultaten für das Originalsystem, fuer das entsprechende Untersuchungen bereits in durchgefuehrt wurden, betrachtet werden. Weiterhin wird ein Ausblick auf weitere Optimierungsmöglichkeiten des Verfahrens gegeben.
28
Pester, M., and S. Rjasanow. "A parallel version of the preconditioned conjugate gradient method for boundary element equations." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800455.
Full textAbstract:
The parallel version of precondition techniques is developed for
matrices arising from the Galerkin boundary element method for
two-dimensional domains with Dirichlet boundary conditions.
Results were obtained for implementations on a transputer network
as well as on an nCUBE-2 parallel computer showing that iterative
solution methods are very well suited for a MIMD computer. A
comparison of numerical results for iterative and direct solution
methods is presented and underlines the superiority of iterative
methods for large systems.
29
Yang, Kangjie Roy. "Simulation of hydrodynamic ram phenomenon using MSC Dytran." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/44033.
Full textAbstract:
Approved for public release; distribution is unlimited<br>Hydrodynamic ram (HRAM) refers to the damage process due to high pressures generated when a high-velocity projectile penetrates a compartment or vessel containing a fluid. A Finite Element model was developed using MSC Dytran to investigate the structural response during the initial phase of HRAM and conduct parametric studies on factors that could affect the tank wall response. The Lagrangian structural shell elements were coupled to the fluid Euler elements using the ALE coupling technique, whereas the projectile was coupled to the fluid using the general coupling technique. This study focused mainly on the structural back wall response where critical components or main structural members on the aircraft could be located. Results from this study show that initial shock wave pressure upon projectile impact is unlikely to have detrimental effects on the exit wall of tank due to its rapid extinction in the fluid. The presence of free surface with lower filling levels reduced both the initial shock pressure and subsequent drag phase pressure. Projectile mass was found to have a strong effect on the exit wall response during the shock phase, but once projectile penetrated the entry wall, results for the drag phase for different projectile mass investigated were inconclusive. Other factors examined included the tank’s material properties and fluid density. Of all the factors being studied, projectile’s velocity was found to have the strongest influence on exit wall response and fluid pressures. Therefore, the damage to exit wall of the tank could be greatly reduced if the entry wall is able to slow the projectile significantly.
30
Mukonoweshuro, Blessing. "Immunogenicity of allogeneic mouse mesenchymal stem cells (MSC)." Thesis, University of Leeds, 2012. http://etheses.whiterose.ac.uk/4140/.
Full textAbstract:
Adult mesenchymal stem cells (MSC) are multipotential cells which can differentiate into various cell types thus giving them utility in tissue engineering regenerative medicine and cell-based therapies. Use of allogeneic MSC offers the prospect of 'off-the-shelf' tissue engineered products and tailor-made 'designer'-therapies with huge benefits to patients and industry. However, their immunological properties are poorly defined and this has hampered their potential clinical utility. Recent studies have suggested that allogeneic MSC are immunoprivileged in addition to possessing immunosuppressive properties. Interestingly, dermal fibroblasts (DF) have also been suggested to be functionally similar to MSC although their immunological properties are controversial. This study sought to systematically investigate the immunomodulatory properties of allogeneic MSC, namely (i) immunosuppression and (ii) (immunogenicity of allogeneic MSC before and after differentiation using an allogeneic mouse model which employed two genetically distinct strains; Balb/c (H2 d) and C3H (H2 k) which are used as responder (recipient) and stimulator (donor) respectively. Immunosuppressive properties were investigated using adaptations of the one-way mixed lymphocyte reaction (MLR) while the immunogenicity was tested using the lymphocyte transformation assays (LTA). DF were similarly tested for comparison. MSC and DF were successfully isolated from the bone marrow and abdominal skin respectively of Balb/c and C3H mice, expanded and characterised by flow cytometry. MSC expressed MHC I, Sca-1, CD29, CD44, CD90.2 and CD105 but not MHC II, CD11b, CD34, CD45, CD80 and CD86. In contrast to MSC, DF were negative for CD29, CD44 and CD105. Both MSC and DF successfully differentiated into adipocytes, chondrocytes and osteocytes in the tri-lineage test; the benchmark test for stem cells. Various parameters including medium changes, cell viability following mitotic inactivation of stimulator cells, type and concentration of serum for medium supplementation, responder to stimulator cell ratio and total cell numbers were tested to determine appropriate conditions for carrying out the MLR and LTA. With regard to the immunosuppressive properties, both syngeneic and allogeneic MSC significantly suppressed one-way MLR and two-way MLR. DF also exhibited similar suppressive potency. In LTA, allogeneic, but not syngeneic MSC stimulated Balb/c lymphocyte proliferation. Interestingly, both syngeneic and allogeneic DF failed to stimulate lymphocyte proliferation. Following chondrogenic differentiation, both syngeneic and allogeneic MSC and DF suppressed one-way MLR, albeit with reduced potency. With regard to their immunogenicity, allogeneic MSC and DF, but not syngeneic MSC and DF significantly stimulated lymphocyte proliferation. Therefore, it was concluded that both allogeneic MSC and DF possess immunosuppressive properties before and after differentiation. Undifferentiated and differentiated allogeneic MSC and differentiated DF however, may not be immunoprivileged. Thus the clinical utility of allogeneic MSC may be limited by their immunogenicity.
31
Hofmann, B. "On Ill-Posedness and Local Ill-Posedness of Operator Equations in Hilbert Spaces." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801185.
Full textAbstract:
In this paper, we study ill-posedness concepts of nonlinear and linear inverse problems
in a Hilbert space setting. We define local ill-posedness of a nonlinear operator
equation $F(x) = y_0$ in a solution point $x_0$ and the interplay between the nonlinear
problem and its linearization using the Frechet derivative $F\acent(x_0)$ . To find an
appropriate ill-posedness concept for the linarized equation we define intrinsic
ill-posedness for linear operator equations $Ax = y$ and compare this approach with
the ill-posedness definitions due to Hadamard and Nashed.
32
Jung, M., and J. F. Maitre. "Some Remarks on the Constant in the Strengthened C.B.S. Inequality: Application to $h$- and $p$-Hierarchical Finite Element Discretizations of Elasticity Problems." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801431.
Full textAbstract:
For a class of two-dimensional boundary value problems including diffusion and elasticity problems it is proved that the constants in the corresponding strengthened Cauchy-Buniakowski-Schwarz (C.B.S.) inequality in the cases of h -hierarchical and p -hierarchical finite element discretizations with triangular meshes differ by the factor 0.75.
For plane linear elasticity problems and triangulations with right isosceles tri- angles formulas are presented that show the dependence of the constant in the C.B.S. inequality on the Poisson's ratio. Furthermore, numerically determined bounds of the constant in the C.B.S. inequality are given for three-dimensional elasticity problems discretized by means of tetrahedral elements.
Finally, the robustness of iterative solvers for elasticity problems is discussed briefly.
33
Ivanov, S. A., and V. G. Korneev. "On the preconditioning in the domain decomposition technique for the p-version finite element method. Part II." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800862.
Full textAbstract:
P-version finite element method for the second order elliptic equation in an arbitrary sufficiently smooth domain is studied in the frame of DD method. Two types square reference elements are used with the products of the integrated Legendre's polynomials for the coordinate functions. There are considered the estimates for the condition numbers, preconditioning of the problems arising on subdomains and the Schur complement, the derivation of the DD preconditioner. For the result we obtain the DD preconditioner to which corresponds the generalized condition number of order (logp )2 . The paper consists of two parts. In part I there are given some preliminary results for 1D case, condition number estimates and some inequalities for 2D reference element. Part II is devoted to the derivation of the Schur complement preconditioner and conditionality number estimates for the p-version finite element matrixes. Also DD preconditioning is considered.
34
Wappler, T., Th Vojta, and M. Schreiber. "Monte-Carlo Simulations of the Dynamical Behavior of the Coulomb Glass." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801378.
Full textAbstract:
We study the dynamical behavior of disordered many-particle systems
with long-range Coulomb interactions by means of damage-spreading
simulations. In this type of Monte-Carlo simulations one investigates the
time evolution of the damage, i.e. the difference of the o ccupation
numbers of two systems, subjected to the same thermal noise. We analyze
the dependence of the damage on temperature and disorder strength. For
zero disorder the spreading transition coincides with the equilibrium phase
transition, whereas for finite disorder, we find an evidence for a dynamical
phase transition well below the transition temperature of the pure system.
35
Jung, M. "Parallelization of multi-grid methods based on domain decomposition ideas." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800781.
Full textAbstract:
In the paper, the parallelization of multi-grid methods for solving second-order elliptic boundary value problems in two-dimensional domains is discussed. The parallelization strategy is based on a non-overlapping domain decomposition data structure such that the algorithm is well-suited for an implementation on a parallel machine with MIMD architecture. For getting an algorithm with a good paral- lel performance it is necessary to have as few communication as possible between the processors. In our implementation, communication is only needed within the smoothing procedures and the coarse-grid solver. The interpolation and restriction procedures can be performed without any communication. New variants of smoothers of Gauss-Seidel type having the same communication cost as Jacobi smoothers are presented. For solving the coarse-grid systems iterative methods are proposed that are applied to the corresponding Schur complement system. Three numerical examples, namely a Poisson equation, a magnetic field problem, and a plane linear elasticity problem, demonstrate the efficiency of the parallel multi- grid algorithm.
36
Tröltzsch, Fredi. "On the Lagrange-Newton-SQP Method for the Optimal Control of Semilinear Parabolic Equations." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800995.
Full textAbstract:
A class of Lagrange-Newton-SQP methods is investigated for optimal control problems
governed by semilinear parabolic initial- boundary value problems. Distributed and boundary
controls are given, restricted by pointwise upper and lower bounds. The convergence of the method
is discussed in appropriate Banach spaces. Based on a weak second order sufficient optimality condition
for the reference solution, local quadratic convergence is proved. The proof is based on the
theory of Newton methods for generalized equations in Banach spaces.
37
Bernert, K. "Tauextrapolation - theoretische Grundlagen, numerische Experimente und Anwendungen auf die Navier-Stokes-Gleichungen." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800506.
Full textAbstract:
The paper deals with tau-extrapolation - a modification of the
multigrid method, which leads to solutions with an improved con-
vergence order. The number of numerical operations depends
linearly on the problem size and is not much higher than for a
multigrid method without this modification. The paper starts
with a short mathematical foundation of the tau-extrapolation.
Then follows a careful tuning of some multigrid components
necessary for a successful application of tau-extrapolation. The
next part of the paper presents numerical illustrations to the
theoretical investigations for one- dimensional test problems.
Finally some experience with the use of tau-extrapolation for the
Navier-Stokes equations is given.
38
Wang, Longlong. "A mesenchymal stem cell (MSC) niche in mouse incisor." Thesis, King's College London (University of London), 2016. https://kclpure.kcl.ac.uk/portal/en/theses/a-mesenchymal-stem-cell-msc-niche-in-mouse-incisor(8f92b75d-f90f-4c58-ab06-682af9f90e95).html.
Full textAbstract:
Mesenchymal stem cells (MSCs) are heterogeneous cell populations that are identified by their in vitro characteristics while their biological properties and in vivo identities are often less understood. Different from human teeth, mouse incisors grow and erupt continuously throughout their lives and compensate for daily abrasions with the existence of stem cells. However, the precise location of the mesenchymal stem cells (MSCs) in the incisor is unclear. Generally, the MSCs in the mouse incisor are believed to be located in the mesenchyme close to the epithelium cervical loops, since the growth and differentiation of the incisor always initiates at the apical end and extends towards the incisal end. The utilization of label-retaining experiments and transgenic reporter mouse lines has enabled further understanding of the less established identities and properties of dental pulp stem cells in vivo. The work described in this thesis demonstrates that the mesenchymal stem cell niche located at the apical end of mouse incisor contains three distinct but connected cell populations: 1) a slow cycling cell population containing Thy-1+ cells essential for tooth dental pulp and odontoblast formation 2) a Ring1/Bcor-associated fast cycling cell population crucial for maintaining tissue growth and homeostasis of epithelium stem cells in labial cervical loop 3) a quiescent long-term cell population marked by Flamingo homologue Celsr1 might respond to generate new stem cells when the stem cells become depleted.
39
Genest, Blaise. "L'odyssée des graphes de diagrammes de séquences ( MSC-Graphes)." Paris 7, 2004. http://www.theses.fr/2004PA077210.
Full text
40
Sotto, David C. "Directing the migration of mesenchymal stem cells with superparamagnetic iron oxide nanoparticles." Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54897.
Full textAbstract:
Cell migration plays an important role in numerous normal and pathological processes. The physical mechanisms of adhesion, protrusion/extension, contractions, and polarization can regulate cell migration speed, persistence time, and downstream effects in paracrine and endocrine signaling. Methods for understanding these biophysical and biochemical responses to date have been limited to the use of external forces acting on mechanotransductive receptors. Additionally, as the use of magnetic nanoparticles for cell tracking and cell manipulation studies continues to gain popularity, so does the importance of understanding the cellular response to mechanical forces caused by these magnetic systems. This thesis work utilizes superparamagnetic iron oxide nanoparticles and static magnets to induce an endogenous magnetic force on the cell membrane. This cell manipulation model is used to better understand the mechanobiological responses of mesenchymal stem cell to SPIO labeling and endogenous force generation. Directionally persistent motility, cytoskeletal reorganization, and altered pro-migratory cytokine secretion is reported in this thesis as a response to SPIO based cell manipulation.
41
Globisch, G., and S. V. Nepomnyaschikh. "The hierarchical preconditioning having unstructured grids." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801398.
Full textAbstract:
In this paper we present two hierarchically preconditioned methods for the fast solution of mesh equations that approximate 2D-elliptic boundary value problems on unstructured quasi uniform triangulations. Based on the fictitious space approach the original problem can be embedded into an auxiliary one, where both the hierarchical grid information and the preconditioner by decomposing functions on it are well defined. We implemented the corresponding Yserentant preconditioned conjugate gradient method as well as the BPX-preconditioned cg-iteration having optimal computational costs. Several numerical examples demonstrate the efficiency of the artificially constructed hierarchical methods which can be of importance in the industrial engineering, where often only the nodal coordinates and the element connectivity of the underlying (fine) discretization are available.
42
Giallongo, Cesarina. "Immune escape mechanisms in hematological diseades: role of the myeloid derived suppressor cells and tumor microenvironment." Doctoral thesis, Università di Catania, 2017. http://hdl.handle.net/10761/3889.
Full textAbstract:
The interactions between the immune system and the tumor cells occur through complex events that lead to tumor eradication or immune evasion by cancer. Recently, the prognostic role of Myeloid derived suppressor cells (MDSC) accumulation has been documented for some hematological malignancies where they correlates with disease progression and persistence of minimal residual disease. We first evaluated the change of MDSC frequency in hematological patients during therapy founding a significant correlation between the number of persistent monocytic-MDSC and major molecular response (MMR) value in chronic myeloid leukemia patients treated with dasatinib. Moreover, our data demonstrated that tumor cells, through the release of soluble factors and exosomes, are able to expand monocytic-MDSC, creating an immunotolerant environment that results in T cell anergy and facilitates tumor growth. In addition, cancer cells are also able to promote immune dysfunction in MSC with their consequent commitment, via TLR4 signaling, toward an activated status promoting immune escape through the polarization of neutrophils in immunosuppressive cells.
43
Fleischer, G. "Multiplication operators and its ill-posedness properties." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801292.
Full textAbstract:
This paper deals with the characterization of multiplication operators,
especially with its behavior in the ill-posed case.
We want to classify the different types and degrees of ill-posedness. We give
some connections between this classification and regularization methods.
44
Hofmann, B., and O. Scherzer. "Local Ill-Posedness and Source Conditions of Operator Equations in Hilbert Spaces." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800957.
Full textAbstract:
The characterization of the local ill-posedness and the local degree of nonlinearity are of particular importance for the stable solution of nonlinear ill-posed problems. We present assertions concerning the interdependence between the ill-posedness of the nonlinear problem and its linearization. Moreover, we show that the concept of the degree of nonlinearity com bined with source conditions can be used to characterize the local ill-posedness and to derive a posteriori estimates for nonlinear ill-posed problems. A posteriori estimates are widely used in finite element and multigrid methods for the solution of nonlinear partial differential equations, but these techniques are in general not applicable to inverse an ill-posed problems. Additionally we show for the well-known Landweber method and the iteratively regularized Gauss-Newton method that they satisfy a posteriori estimates under source conditions; this can be used to prove convergence rates results.
45
Apel, Th, and G. Lube. "Anisotropic mesh refinement for singularly perturbed reaction diffusion problems." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199801080.
Full textAbstract:
The paper is concerned with the finite element resolution of layers appearing
in singularly perturbed problems. A special anisotropic grid of Shishkin type
is constructed for reaction diffusion problems. Estimates of the finite element
error in the energy norm are derived for two methods, namely the standard
Galerkin method and a stabilized Galerkin method. The estimates are uniformly
valid with respect to the (small) diffusion parameter. One ingredient is a
pointwise description of derivatives of the continuous solution. A numerical
example supports the result.
Another key ingredient for the error analysis is a refined estimate for
(higher) derivatives of the interpolation error. The assumptions on admissible
anisotropic finite elements are formulated in terms of geometrical conditions
for triangles and tetrahedra. The application of these estimates is not
restricted to the special problem considered in this paper.
46
Apel, Thomas, and Gert Lube. "Anisotropic mesh refinement in stabilized Galerkin methods." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800640.
Full textAbstract:
The numerical solution of the convection-diffusion-reaction problem is considered in two and three dimensions. A stabilized finite element method of Galerkin/Least squares type accomodates diffusion-dominated as well as convection- and/or reaction- dominated situations. The resolution of boundary layers occuring in the singularly perturbed case is accomplished using anisotropic mesh refinement in boundary layer regions. In this paper, the standard analysis of the stabilized Galerkin method on isotropic meshes is extended to more general meshes with boundary layer refinement. Simplicial Lagrangian elements of arbitrary order are used.
47
Meyer, A., and M. Pester. "Verarbeitung von Sparse-Matrizen in Kompaktspeicherform KLZ/KZU." Universitätsbibliothek Chemnitz, 1998. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-199800520.
Full textAbstract:
The paper describes a storage scheme for sparse symmetric or
nonsymmetric matrices which has been developed and used for many
years at the Technical University of Chemnitz. An overview of
existing library subroutines using such matrices is included.
48
Ma, Zheng. "Analyse von Schnittstellenkompatibilität von Steuergeräten auf Basis von MSC-Beschreibungen." Master's thesis, Universitätsbibliothek Chemnitz, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200800289.
Full textAbstract:
In modernen Fahrzeugen befindet sich eine Vielzahl von Steuergeräten, die verschiedenste
Funktionen, wie z.B. das Antiblockiersystem (ABS) realisieren. Die Funktionalitäten
von Steuergeräten werden heute mit unterschiedlichen Methoden beschrieben. Eine
dieser Methoden sind Message Sequence Charts (MSCs). Aufgrund der Freiheitsgrade
von MSCs gibt es verschiedene Möglichkeiten gleiche Funktionalität unterschiedlich zu
beschreiben. In dieser Arbeit wird eine Methode definiert, wie verschiedene MSCs hinsichtlich
Funktionskompatibilität auf Basis von endlichen Automaten untersucht werden
können.
Diese Diplomarbeit ist in zwei Schwerpunkte gegliedert. Zum einen soll ein Konzept
für die Transformation des MSCs in der entsprechenden Automaten-Darstellung und einen
Vergleich-Algorithmus zur Rückwärtskompatibilitätsanalyse der endlichen Automaten entwickelt
werden. Zum anderen ist es Aufgabe, die Methode auf Basis von Java zu implementieren
und in die Software-Plattform CAMP zu integrieren.
49
Bourduas, Stephan. "Generation of SDL specifications from UML and MSC use cases." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/MQ64058.pdf.
Full text
50
Zanin, Daniel Bispo. "Metodologia de análise de whirl flutter utilizando o MSC/NASTRAN." Instituto Tecnológico de Aeronáutica, 2011. http://www.bd.bibl.ita.br/tde_busca/arquivo.php?codArquivo=2990.
Full textAbstract:
O whirl flutter é um fenômeno aeroelástico característico de aeronaves com motores a hélice. Trata-se da instabilidade do movimento de precessão da hélice devido ao acoplamento dos deslocamentos de arfagem e guinada em conjunto com a atuação das forças aerodinâmicas, que alimentam as oscilações do sistema. Inicialmente, o presente trabalho busca entender este mecanismo de flutter através de uma revisão bibliográfica e da obtenção das equações de movimento para um sistema simples com dois graus de liberdade. A seguir, apresenta-se uma metodologia para os cálculos de whirl flutter com o uso do software comercial MSC/NASTRAN. O processo é aplicado ao estudo de caso de uma aeronave bimotora de pequeno porte, utilizando um modelo de elementos finitos para a estrutura de fixação do motor. A introdução dos efeitos giroscópicos e aerodinâmicos da hélice é proporcionada por um pré-processador externo, que também tem o seu funcionamento apresentado. As respostas do NASTRAN para o estudo de caso são então comparadas aos resultados de um programa específico para o cálculo de whirl flutter.