Sökning: "Erik Janson"

Hittade 5 avhandlingar innehållade orden Erik Janson.

1. 1. Degrees in Random Graphs and Tournament Limits

   Författare :Erik Thörnblad; Svante Janson; Erik Broman; Daniel Kráľ; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Random graphs; degree distributions; degree sequences; graph limits; tournaments; Mathematics; Matematik;

   Sammanfattning : This thesis consists of an introduction and six papers on the topics of degree distributions in random graphs and tournaments and their limits.The first two papers deal with a dynamic random graph, evolving in time through duplication and deletion of vertices and edges. In Paper I we study the degree densities of this model. LÄS MER

3. 2. Potential Flow Panel Methods for the Calculation of Free-surface Flows with Lift

   Författare :Carl-Erik Janson; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; desingularized; shape optimization; Rankine source; waves; OCTOPUS; dipole; MMA; Dawson operator; boundary layer; vortex; Method of Moving Asymptotes; nonlinear; sailing yacht; four point operator; surface piercing wing; Navier-Stokes; numerical method; lift force; raised panel method; discrete Fourier transform; collocation point shift; potential flow; CFD; free surface; induced drag; SHIPFLOW; dispersion; damping; analytical method; hydrofoil;

   Sammanfattning : Two non-linear Rankine-source panel methods are developed and implemented in the same computer code. The first method uses a four-point upwind operator on the free-surface to compute the velocity derivatives and to enforce the radiation condition while the second method uses an analytical expression for the velocity derivatives and a collocation point shift one panel upstream to prevent upstream waves. LÄS MER

4. 3. Asymptotics of a Random Graph Model

   Författare :Erik Thörnblad; Svante Janson; Stanislav Volkov; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : .... LÄS MER

5. 4. Selected Problems in Financial Mathematics

   Författare :Erik Ekström; Johan Tysk; Svante Janson; Lane P. Hughston; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematical analysis; American options; convexity; monotonicity in the volatility; robustness; optimal stopping; parabolic equations; free boundary problems; volatility; Russian options; game options; excessive functions; superreplication; smooth fit; Matematisk analys; Mathematical analysis; Analys;

   Sammanfattning : This thesis, consisting of six papers and a summary, studies the area of continuous time financial mathematics. A unifying theme for many of the problems studied is the implications of possible mis-specifications of models. Intimately connected with this question is, perhaps surprisingly, convexity properties of option prices. LÄS MER

7. 5. Optimal and Hereditarily Optimal Realizations of Metric Spaces

   Författare :Alice Lesser; Svante Janson; Lars-Erik Persson; Anders Johansson; Vincent Moulton; Pierre Flener; Charles Semple; Uppsala universitet; []
   Nyckelord :Applied mathematics; optimal realization; hereditarily optimal realization; tight span; phylogenetic network; Buneman graph; split decomposition; T-theory; finite metric space; topological graph theory; discrete geometry; Tillämpad matematik;

   Sammanfattning : This PhD thesis, consisting of an introduction, four papers, and some supplementary results, studies the problem of finding an optimal realization of a given finite metric space: a weighted graph which preserves the metric's distances and has minimal total edge weight. This problem is known to be NP-hard, and solutions are not necessarily unique. LÄS MER