Events - Page 47

Roberto Conti , Università di Chieti-Pescara ‘G. D’Annunzio’, Italy, will give a talk on "Sectors of scaling limit nets and asymptotic morphisms".

Abstract: In the algebraic approach to 4D-QFT the main object of study is a local net, namely an isotonous correspondence between spacetime regions and operator algebras on a fixed Hilbert space satisfying physically motivated properties including Einstein causality. The so-called DHR superselection sectors of the net are then described by certain (inner equivalence classes of) *-endomorphisms of the C*-algebra of quasi-local observables. For any local net, one may also consider its associated scaling limit nets, carrying the information on the short distance limit of the given QFT (roughly, this is the algebraic version of the renormalization group). In this talk we will argue that the superselection sectors of a scaling limit net can be described in terms of suitable maps of the original theory, that are similar to the asymptotic morphisms appearing in E-theory of Connes and Higson. This is a new arena where concepts from AQFT and NCG are merged together, and provides a first step for an alternative (rigorous, model independent) approach to the notion of confinement. (This is joint work with G. Morsella).  

Kukatharmini Tharmaratnam (Matematisk Institutt, Universitetet i Oslo) skal snakke om

Robust estimation for penalized regression splines

Jukka Lempa, CMA, holder et seminar med tittelen: Utility maximization with commodity futures

This lecture series will be based on the introduction, chapters 1 and 2 of the book "Topics in Optimal Transportation" by Cedric Villani.

Jukka Lempa,CMA, holder et seminar med tittelen:Optimal Stopping with Random Exercise Lag

This lecture series will be based on the introduction, chapters 1 and 2 of the book "Topics in Optimal Transportation" by Cedric Villani.

I extend my 2005 AG&T paper with Bruner from the circle case to more general Lie groups.  There are new results about infinite cycles for actions by the torus T² or the rotation group SO(3). 

I will go through the simplest case of my 2005 AG&T paper with Bruner, showing that certain classes, in the homological homotopy fixed point spectral sequence for a circle action on a commutative ring spectrum, are infinite cycles. The idea of using an universal example may lead to generalizations for actions by tori or other Lie groups. 

Rüdiger Kiesel,Uni. Essen/CMA, holder et seminar med tittelen: Market Risk Premium in Power Markets

Torben Mideksa (Cicero) skal snakke om

Electricity demand in a changing climate

We show that the hermitian K-theory of regular schemes (with 2 a unit in the ring of regular functions) is represented in the A^1-homotopy category of Morel-Voevodsky by the ind-scheme of non-degenerate Grassmanians.

Min-ge Xie, Department of Statistics, Rutgers University, skal snakke om

Confidence distribution and a Frequentist Approach to Incorporate Expert Opinions

Anders Barstad, Statistisk Sentralbyrå, skal snakke om

Explaining Changing Suicide Rates in Norway 1948-2004: The Role of Social Integration

Ingram Olkin (Department of Statistics, Stanford University) skal snakke om

Meta-Analysis: Statistical Methods for Combining the Results of Independent Studies

Chris Wikle (Department of Statistics, University of Missouri) skal snakke om

Nonlinear Dynamic Spatio-Temporal Statistical Models

This seminar will be focused on some elementary structural systems such as the cantilever beam. The cantilever is an old problem in structural mechanics already investigated by Galileo (1638) from equilibrium and strength arguments. This structural paradigm will be reconsidered here using buckling, post-buckling and inelastic theory. We will first present some fundamental buckling results for axially loaded columns. This model covers the case of a tree under its own weight or gives an answer to Babel mythology, at least from the stability theory point of view. This in-plane buckling problem in presence of distributed and concentrated axial forces has been recently exactly solved using hypergeometric functions. The post-buckling behavior associated with a nonlinear boundaryvalue problem will be also discussed using some asymptotic and numerical methods. The out-of-plane buckling problem of this cantilever beam will be further investigated. The lateral-torsiona l buckling problem of Prandtl (1899) dealing with the stability boundary of a beam loaded by its own weight and a concentrated force will be also solved. The convexity theorem of Papkovitch and Schaefer (1934) will be shown for these structural problems. The seminar will be concluded by the inelastic analysis of the beam in bending. We will show the need to develop a nonlocal plasticity law to describe the post-failure behavior of a beam in presence of softening. Wood’s paradox (1968) is overcome by using a nonlocal plasticity model. The Galileo problem is then revisited in the light of nonlocal mechanics. Applications of such theoretical studies can be found in the field of civil engineering at the macro scale (reinforced concrete design, timber beams, steel or composite beams…), but also at micro- or nano-scales including for instance nanostructures.

Challamel is Professor of Civil Engineering, University of South Brittany, Lorient, France, and Marie Curie Fellow in solid mechanics (faststoffmekanikk) at UiO (2011/2012).

Volume tracking is a popular method for the computation of two phase flow problems. In this talk we present a reformulation of volume tracking in two dimensions in terms of an explicit tracking of the interface between the two immiscible phases. This allows for a higher order accurate representation of the interface with respect to the spatial discretization while conserving the mass up to roundoff precision.

Joris Verschaeve is postdoc at the Mechanics Division, Department of Mathematics, University of Oslo.

Ocean Engineering (OE) is considered by many to be a matured field which is mainly controlled by the oil industries. However, due to the growing interdiciplinary nature of OE, it presents new exciting challenges for scientists and engineers with a solid background in topics like hydrodynamics, acoustics, physio-chemistry as well as electro-kinetics, electromagnetics and control theory. Some practical examples will be discussed.

Touvia Miloh is professor at Tel Aviv University.

An idealized mathematical model of tsunami evolution in deep sea and across the continental shelf is proposed. The initial value problem in deep sea is related to the well known Cauchy- Poisson problem, and the tsunami propagation across the continental shelf is derived using the linearized shallow water equations.

When analyzing different cases of tsunamis in deep sea it was found that tsunamis evolve into two basic wave types. One resembles a single wave and the other a wave packet. The analysis of different cases of tsunamis at the shoreline reveals that the continental shelf, due to its geometrical properties, serves as a tsunami amplifier, producing tsunami amplitudes up to 20 times larger than those at the edge of the continental shelf.

A comparison with tsunami measurements suggests that the idealized model may be used for a reliable assessment of the principle hydrodynamic properties of the tsunami, such as the tsunami amplitude and its half- period.

The new mathematical model for tsunami evolution is used to derive a synthetic tsunami database for the southern part of the Eastern Mediterranean coast. Information about coastal tsunami amplitudes, half-periods, currents, and inundation levels is presented.

Michael Stiassnie is professor at the Department of Civil and Environmental Engineering, Technion – Israel Institute of Technology.

Kjetil Røysland, Avdeling for biostatistikk, Universitetet i Oslo, skal snakke om

Evaluation of counterfactual interventions in epidemiology

Simulations of Fluid-Solid interactions (FSI) are becoming more common as faster computers enables the study of larger models including both fluids and solids. In many applications it is of significant importance to determine the impact that a flowing fluid has on the mechanical structure surrounding it. Vortex-induced vibrations can give structural failure due to fatigue, but it can also produce undesired acoustic noise. During the seminar, several examples of FSI problems and solutions will be demonstrated. The examples include the study of flow induced vibrations in a compressor exhaust, the dynamic flow of oil through a filter, the impact of water waves on a submerged object, etc.

Large-eddy simulations are also advancing in the industrial CFD society. RANS modeling has shown to be insufficient in many complex flow situations, and LES has proven to provide answers to many fundamental questions in turbulent flows. A brief demonstration  of an example with flow over a wing profile is presented. Using LES, it is possible to extract valuable information regarding lift, drag, etc., but it is also possible to visualize the turbulent structures evolving from the boundary layer on the wing.

Love Håkansson is at EDR - Engineering Data Resources

Arvid Raknerud, Statistisk Sentralbyrå, skal snakke om

Indirect inference methods for stochastic volatility models based on non-Gaussian Ornstein-Uhlenbeck processes