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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.
51

On completeness of root functions of Sturm-Liouville problems with discontinuous boundary operators

Shlapunov, Alexander, Tarkhanov, Nikolai January 2012 (has links)
We consider a Sturm-Liouville boundary value problem in a bounded domain D of R^n. By this is meant that the differential equation is given by a second order elliptic operator of divergent form in D and the boundary conditions are of Robin type on bD. The first order term of the boundary operator is the oblique derivative whose coefficients bear discontinuities of the first kind. Applying the method of weak perturbation of compact self-adjoint operators and the method of rays of minimal growth, we prove the completeness of root functions related to the boundary value problem in Lebesgue and Sobolev spaces of various types.
52

Local and disjointness structures of smooth Banach manifolds

Wang, Ya-Shu 26 December 2009 (has links)
Peetre characterized local operators defined on the smooth section space over an open subset of an Euclidean space as ``linear differential operators'. We look for an extension to such maps of smooth vector sections of smooth Banach bundles. Since local operators are special disjointness preserving operators, it leads to the study of the disjointness structure of smooth Banach manifolds. In this thesis, we take an abstract approach to define the``smooth functions', via the so-called S-category. Especially, it covers the standard classes C^{n} and local Lipschitz functions, where 0≤n≤¡Û. We will study the structure of disjointness preserving linear maps between S-smooth functions defined on separable Banach manifolds. In particular, we will give an extension of Peetre's theorem to characterize disjointness preserving linear mappings between C^n or local Lipschitz functions defined on locally compact metric spaces.
53

Lipschitz Stability of Solutions to Parametric Optimal Control Problems for Parabolic Equations

Malanowski, Kazimierz, Tröltzsch, Fredi 30 October 1998 (has links) (PDF)
A class of parametric optimal control problems for semilinear parabolic equations is considered. Using recent regularity results for solutions of such equations, sufficient conditions are derived under which the solutions to optimal control problems are locally Lipschitz continuous functions of the parameter in the L1-norm. It is shown that these conditions are also necessary, provided that the dependence of data on the parameter is sufficiently strong.
54

Novel and Efficient Numerical Analysis of Packaging Interconnects in Layered Media

Zhu, Zhaohui January 2005 (has links)
Technology trends toward lower power, higher speed and higher density devices have pushed the package performance to its limits. The high frequency effects e.g., crosstalk and signal distortion, may cause high bit error rates or malfunctioning of the circuit. Therefore, the successful release of a new product requires constant attention to the high frequency effects through the whole design process. Full-wave electromagnetic tools must be used for this purpose. Unfortunately, currently available full-wave tools require excessive computational resources to simulate large-scale interconnect structures.A prototype version of the Full-Wave Layered-Interconnect Simulator (UA-FWLIS), which employs the Method of Moments (MoM) technique, was developed in response to this design need. Instead of using standard numerical integration techniques, the MoM reaction elements were analytically evaluated, thereby greatly improving the computational efficiency of the simulator. However, the expansion and testing functions that are employed in the prototype simulator involve filamentary functions across the wire. Thus, many problems cannot be handled correctly. Therefore, a fundamental extension is made in this dissertation to incorporate rectangular-based, finite-width expansion and testing functions into the simulator. The critical mathematical issues and theoretical issues that were met during the extension are straightened out. The breakthroughs that were accomplished in this dissertation lay the foundation for future extensions. A new bend-cell expansion function is also introduced, thus allowing the simulator to handle bends on the interconnects with fewer unknowns. In addition, the Incomplete Lipschitz-Hankel integrals, which are used in the analytical solution, are studied. Two new series expansions were also developed to improve the computational efficiency and accuracy.
55

ANALYTICAL METHODS FOR TRANSPORT EQUATIONS IN SIMILARITY FORM

Tiwari, Abhishek 01 January 2007 (has links)
We present a novel approach for deriving analytical solutions to transport equations expressedin similarity variables. We apply a fixed-point iteration procedure to these transformedequations by formally solving for the highest derivative term and then integrating to obtainan expression for the solution in terms of a previous estimate. We are able to analyticallyobtain the Lipschitz condition for this iteration procedure and, from this (via requirements forconvergence given by the contraction mapping principle), deduce a range of values for the outerlimit of the solution domain, for which the fixed-point iteration is guaranteed to converge.
56

Daugiamačių simpleksinių Lipšico algoritmų su nežinoma Lipšico konstanta ir įvairiais simplekso centrais kūrimas ir eksperimentinis tyrimas / Development and experimental investigation of multidimensional simplicial Lipschitz optimization with unkwn Lipschitz constant and variuos centers

Talačkaitė, Simona 24 July 2014 (has links)
Globaliojo optimizavimo metodai, pagrįsti Lipšico rėžių apskaičiavimu, yra plačiai taikomi įvairių optimizavimo uždavinių sprendimui. Tačiau Lipšico metodai dažniausiai remiasi prielaida, kad Lipšico konstanta žinoma iš anksto, o tai retas atvejis sprendžiant praktinius uždavinius. Todėl Simonos Talačkaitės magistro darbe yra toliau nagrinėjama aktuali ir svarbi problematika iškylanti realizuojant Lipšico metodus nesiremiančius jokiomis išankstinėmis prielaidomis apie Lipšico konstantą. Praktinio tiriamojo pobūdžio magistro darbe iškeliamas toks pagrindinis tikslas: ištirti daugiamačių simpleksinių globaliojo optimizavimo algoritmų su nežinoma Lipšico konstanta efektyvumą priklausomai nuo naudojamo simplekso centro. Šiam tikslui pasiekti buvo iškelti šie uždaviniai: apžvelgti naujausią literatūrą skirta Lipšico metodams su nežinoma Lipšico konstanta; matematiškai išnagrinėti įvairių daugiamačių simplekso centrų apskaičiavimus bendru atveju bei juos realizuoti Matlab aplinkoje; papildyti simpleksinį globaliojo optimizavimo DISIMPL algoritmą šių simpleksų centrų apskaičiavimo paprogramėmis; eksperimentiškai ištirti pasiūlytų rezultatų praktiškumą sprendžiant testinius optimizavimo uždavinius. / This work analyzes Global optimization objectives, the most important it will be algorithms with simplicial Lipšico constant. Also, this work analyzes multidi- mensional DIRECT algorithm. We will provide dividing in higher dimennsions DIRECT algorithm. Then analyzes two simplex and apply the solutions. The hand simplex to smallerpartitions. Perceive multidimensional DIRECT algorithm division rules. In this work wrote a lot about simplicial center about dividing of hyoer-cube. Finally, the experiment it will be about the best way, how we can …nd circle center ir diferent way. Simplex centers using 8 test funkcions , changing the number of iterations and mistakes number. Create tables and to analyzes them. The purpose of this paper work is to introduce the simplex algorithm for global optimization with unknown Lipšicas constant depending on the e¢ ciency of the division of the rules used in the simplex.
57

Ergodic optimization in the shift

Siefken, Jason 06 August 2010 (has links)
Ergodic optimization is the study of which ergodic measures maximize the integral of a particular function. For sufficiently regular functions, e.g. Lipschitz/Holder continuous functions, it is conjectured that the set of functions optimized by measures supported on a periodic orbit is dense. Yuan and Hunt made great progress towards showing this for Lipschitz functions. This thesis presents clear proofs of Yuan and Hunt’s theorems in the case of the Shift as well as introducing a subset of Lipschitz functions, the super-continuous functions, where the set of functions optimized by measures supported on a periodic orbit is open and dense.
58

Lipschitz and commutator estimates, a unified approach

Potapov, Denis Sergeevich, January 2007 (has links)
Thesis (Ph.D.)--Flinders University, School of Informatics and Engineering, Dept. of Mathematics. / Typescript bound. Includes bibliographical references: (leaves 135-140) and index. Also available online.
59

Perturbations of Kähler-Einstein metrics /

Roth, John Charles. January 1999 (has links)
Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (leaves [86]-88).
60

Applications of variational analysis to optimal trajectories and nonsmooth Hamilton-Jacobi theory /

Galbraith, Grant N., January 1999 (has links)
Thesis (Ph. D.)--University of Washington, 1999. / Vita. Includes bibliographical references (p. 87-91).

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