Mon, 31 Jan 2005
15:45
DH 3rd floor SR

Joint work with Thomas Duquesne on Growth of Levy forests

Dr Matthias Winkel
(Department of Statistics, Oxford)
Abstract

It is well-known that the only space-time scaling limits of Galton-Watson processes are continuous-state branching processes. Their genealogical structure is most explicitly expressed by discrete trees and R-trees, respectively. Weak limit theorems have been recently established for some of these random trees. We study here a Markovian forest growth procedure that allows to construct the genealogical forest of any continuous-state branching process with immigration as an a.s. limit of Galton-Watson forests with edge lengths. Furthermore, we are naturally led to continuous forests with edge lengths. Another strength of our method is that it yields results in the general supercritical case that was excluded in most of the previous literature.

Fri, 28 Jan 2005
14:15
DH 3rd floor SR

The Malliavin gradient method for calibration of stochastic volatility
models

Christian Ewald
Abstract

We discuss the application of gradient methods to calibrate mean reverting

stochastic volatility models. For this we use formulas based on Girsanov

transformations as well as a modification of the Bismut-Elworthy formula to

compute the derivatives of certain option prices with respect to the

parameters of the model by applying Monte Carlo methods. The article

presents an extension of the ideas to apply Malliavin calculus methods in

the computation of Greek's.

Thu, 27 Jan 2005
15:00
Rutherford Appleton Laboratory, nr Didcot

The use of coupled solvers for complex multiphase and reacting flows

Dr Ian Jones
(ANSYS Europe)
Abstract

Many industrial flow problems, expecially in the minerals and process

industries, are very complex, with strong interactions between phases

and components, and with very different length and time scales. This

presentation outlines the algorithms used in the CFX-5 software, and

describes the extension of its coupled solver approach to some

multi-scale industrial problems. including Population Balance modelling

to predict size distributions of a disperse phase. These results will be

illustrated on some practical industrial problems.

Mon, 24 Jan 2005
15:45
DH 3rd floor SR

Fractals and conformal invariance

Professor Stanislov Smirnov
(Royal Institute of Technology, Stockholm)
Abstract

It became apparent during the last decade that in several questions in classical complex analysis extremal configurations are fractal, making them very difficult to attack: it is not even clear how to construct or describe extremal objects. We will argue that the most promising approach is to consider conformally self-similar random configurations, which should be extremal almost surely.