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Untersuchung des Informationsverlustes von Zeitreihen beim Übergang von Minuten- zu ViertelstundendurchschnittswertenSchmiedel, Anne 09 December 2011 (has links)
Es erfolgte die Untersuchung der Eigenschaften der gegebenen Zeitreihen der Wirkleistung von zwei Windenergieanlagen sowie des gesamten Windparks. Außerdem analysiert wurden die entsprechenden Eigenschaften der auf Viertelstundendaten konvertierten Reihen. Diese Eigenschaften, wie z.B. Mittelwert, Varianz o.a. Maximum wurden als Informationen angesehen und so ermöglichte die Gegenüberstellung einen Rückschluss auf dem Informationsverlust. Da die gegebene Einspeiseleistung keine Periodizitäten aufwies, erfolgte anschließend die Erzeugung synthetischer Daten.:Einleitung
1. Mathematische Grundlagen
2. Datenanalyse
3. Erzeugung und Untersuchung synthetischer Daten
4. Zusammenfassung und Ausblick
A Anhang
Literaturverzeichnis
Ehrenwörtliche Erklärung
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Eigenvalues of compactly perturbed linear operatorsHansmann, Marcel 02 August 2018 (has links)
This cumulative habilitation thesis is concerned with eigenvalues of compactly perturbed operators in Banach and Hilbert spaces. A general theory for studying such eigenvalues is developed and applied to the study of some concrete operators of mathematical physics.
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Regularizability of ill-posed problems and the modulus of continuityBot, Radu Ioan, Hofmann, Bernd, Mathe, Peter January 2011 (has links)
The regularization of linear ill-posed problems is based on their conditional well-posedness when restricting the problem to certain classes of solutions. Given such class one may consider several related real-valued functions, which measure the wellposedness of the problem on such class. Among those functions the modulus of continuity is best studied. For solution classes which enjoy the additional feature of being star-shaped at zero, the authors develop a series of results with focus on continuity properties of the modulus of continuity. In particular it is highlighted that the problem is conditionally well-posed if and only if the modulus of continuity is right-continuous at zero. Those results are then applied to smoothness classes in Hilbert space. This study concludes with a new perspective on a concavity problem for the modulus of continuity, recently addressed by two of the authors in "Some note on the modulus of continuity for ill-posed problems in Hilbert space", 2011.
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Measure-perturbed one-dimensional Schrödinger operators: A continuum model for quasicrystalsSeifert, Christian 27 November 2012 (has links)
In this Dissertation thesis the spectral theory of Schrödinger operators modeling quasicrystals in dimension one ist investigated. We allow for a large class of measures as potentials covering also point interactions.
The main results can be stated as follows: If the potential can be very well approximated by periodic potentials, then the correspondig Schrödinger operator does not have any eigenvalues. If the potential is aperiodic and satisfies a certain finite local complexity condition, the absolutely continuous spectrum is absent. We also prove Cantor spectra of zero Lebesgue measure for a large class of (a randomized version of) the operator.
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A generalization of the Funk–Radon transform to circles passing through a fixed pointQuellmalz, Michael January 2015 (has links)
The Funk–Radon transform assigns to a function on the two-sphere its mean values along all great circles. We consider the following generalization: we replace the great circles by the small circles being the intersection of the sphere with planes containing a common point ζ inside the sphere. If ζ is the origin, this is just the classical Funk–Radon transform. We find two mappings from the sphere to itself that enable us to represent the generalized Radon transform in terms of the Funk–Radon transform. This representation is utilized to characterize the nullspace and range as well as to prove an inversion formula of the generalized Radon transform.
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Mean Eigenvalue Counting Function Bound for Laplacians on Random NetworksSamavat, Reza 15 December 2014 (has links)
Spectral graph theory widely increases the interests in not only discovering new properties of well known graphs but also proving the well known properties for the new type of graphs. In fact all spectral properties of proverbial graphs are not acknowledged to us and in other hand due to the structure of nature, new classes of graphs are required to explain the phenomena around us and the spectral properties of these graphs can tell us more about the structure of them. These both themes are the body of our work here. We introduce here three models of random graphs and show that the eigenvalue counting function of Laplacians on these graphs has exponential decay bound. Since our methods heavily depend on the first nonzero eigenvalue of Laplacian, we study also this eigenvalue for the graph in both random and nonrandom cases.
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Curtailing Renewable Feed-In Peaks and Its Impact on Power Grid Extensions in Germany for the Year 2030Möst, Dominik, Gunkel, David 02 April 2025 (has links)
Transmission grid extension is a central aspect of the future energy system transition. This is due to the diverging occurrence of renewable energy feed-in and consumption. The existing layout of the German grid was not designed to accommodate this divergence. To analyze the most cost-effective grid extensions, efficient methods for techno-economic analysis are required. The challenge of conducting an analysis of grid extensions involves the lumpy investment decisions and the non-linear character of several restrictions in a real-data environment. The addition of new lines makes the grid characteristic variable for approximately load flow calculations. The following paper presents an application of the Benders Decomposition, dividing the problem into an extension and a dispatch problem combined with a Karush–Kuhn–Tucker-system. This combination enables one to solve the problem within reasonable time by using the favorable conditions contained in the sub-problem. The method is applied to the analysis of the integration of renewable energy within the context of German transmission grid extension planning for the year 2030. It can be shown that curtailing feed-in peaks of renewables can significantly reduce the extent of grid extensions necessary to sustain the energy system in Germany.
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Unbounded operators on Hilbert C*-modules: graph regular operatorsGebhardt, René 28 November 2016 (has links)
Let E and F be Hilbert C*-modules over a C*-algebra A. New classes of (possibly unbounded) operators t: E->F are introduced and investigated - first of all graph regular operators. Instead of the density of the domain D(t) we only assume that t is essentially defined, that is, D(t) has an trivial ortogonal complement. Then t has a well-defined adjoint. We call an essentially defined operator t graph regular if its graph G(t) is orthogonally complemented and orthogonally closed if G(t) coincides with its biorthogonal complement. A theory of these operators and related concepts is developed: polar decomposition, functional calculus. Various characterizations of graph regular operators are given: (a, a_*, b)-transform and bounded transform. A number of examples of graph regular operators are presented (on commutative C*-algebras, a fraction algebra related to the Weyl algebra, Toeplitz algebra, C*-algebra of the Heisenberg group). A new characterization of operators affiliated to a C*-algebra in terms of resolvents is given as well as a Kato-Rellich theorem for affiliated operators. The association relation is introduced and studied as a counter part of graph regularity for concrete C*-algebras.:Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Sightings
1. Unitary *-module spaces
Algebraic essence of adjointability on Hilbert C*-modules . . . . . 13
a) Operators on Hilbert C*-modules - Notions. . . . . . . . . . . . . . 13
b) Essential submodules and adjointability . . . . . . . . . . . . . . . . 15
c) From Hilbert C*-modules to unitary *-module spaces . . . . . . 16
2. Operators on unitary *-module spaces
Basic theory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3. Graph regularity
Pragmatism between weak and (strong) regularity . . . . . . . . . 27
a) Types of regularity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
b) The case C(X) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
c) Graph regularity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Transition. Orthogonal complementability and topology
Back to Hilbert C*-modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Graph regular operators on Hilbert C*-modules
4. Commutative case: Operators on C_0(X)
Phenomena . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Interjection. Unboundedness and graph regularity . . . . . . . . . . 55
5. Relation to adjointable operators
Sources of graph regularity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
6. Concrete C*-algebras
Association relation and affiliation relation . . . . . . . . . . . . . . . . 61
7. Examples
Graph regular operators that are not regular . . . . . . . . . . . . . 67
a) Position and momentum operators as graph regular
operators on a fraction algebra related to the Weyl algebra . . 67
b) A graph regular but not regular operator on the
group C*-algebra of the Heisenberg group . . . . . . . . . . . . . . . 69
c) Unbounded Toeplitz operators . . . . . . . . . . . . . . . . . . . . . . . 70
8. Bounded transform
The canonical regular operator associated to a graph regular
operator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73
9. Absolute value and polar decomposition . . . . . . . . . . . . . . . 79
10. Functional calculus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
11. Special matrices of C*-algebras
Counter examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
Abstract and open questions . . . . . . . . . . . . . . . . . . . . . . . . . 89
Notations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
Dank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
Erklärung . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
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Conditional stability estimates for ill-posed PDE problems by using interpolationTautenhahn, Ulrich, Hämarik, Uno, Hofmann, Bernd, Shao, Yuanyuan January 2011 (has links)
The focus of this paper is on conditional stability estimates for ill-posed inverse problems in partial differential equations. Conditional stability estimates have been obtained in the literature by a couple different methods. In this paper we propose a method called interpolation method, which is based on interpolation in variable Hilbert scales. We are going to work out the theoretical background of this method and show that optimal conditional stability estimates are obtained. The capability of our method is illustrated by a comprehensive collection of different inverse and ill-posed PDE problems containing elliptic and parabolic problems, one source problem and the problem of analytic continuation.
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Oscillatory Solutions to Hyperbolic Conservation Laws and Active Scalar EquationsKnott, Gereon 09 September 2013 (has links)
In dieser Arbeit werden zwei Klassen von Evolutionsgleichungen in einem Matrixraum-Setting studiert: Hyperbolische Erhaltungsgleichungen und aktive skalare Gleichungen. Für erstere wird untersucht, wann man Oszillationen mit Hilfe polykonvexen Maßen ausschließen kann; für Zweitere wird mit Hilfe von Oszillationen gezeigt, dass es unendlich viele periodische schwache Lösungen gibt.
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