MEXIT: Maximal un-coupling times for stochastic processes

Classical coupling constructions arrange for copies of the same Markov process started at two different initial states to become equal as soon as possible. In this paper, we consider an alternative coupling framework in which one seeks to arrange for two different Markov (or other stochastic) processes to remain equal for as long as possible, when started in the same state. We refer to this “un-coupling” or “maximal agreement” construction as MEXIT, standing for “maximal exit”. After highlighting the importance of un-coupling arguments in a few key statistical and probabilistic settings, we develop an explicit MEXIT construction for stochastic processes in discrete time with countable state-space. This construction is generalized to random processes on general state-space running in continuous time, and then exemplified by discussion of MEXIT for Brownian motions with two different constant drifts.     

Effect of Shear Displacement and Stress Changes on Fracture Hydraulic Aperture and Flow Anisotropy

Transport in Porous Media - Fluid flow in fractures has the potential to drastically change the economic, environmental, and safety risks associated with a subsurface operation. This work focuses...     

Influence of wall constructions on the load-carrying capability of light-weight structures

Results of systematic numerical studies are presented which suggest that suitable alternative wall constructions may lead to elastic load-carrying capacities of light-weight structures which significantly exceed those of conventional monocoque constructions, and that in certain cases this improvement may also be accompanied by a decrease in imperfection-sensitivity. Two kinds of wall modifications are considered: a hybrid wall construction where the skin of a light-weight structure is coated with a low-density material, and nonhomogeneous – in particular lattice and biaxially corrugated – wall constructions. The paper focuses on the elastic load-carrying behavior of shell- and plate-like structures, and structural efficiency is assessed on the basis of their bifurcation buckling resistance while other design criteria, such as e.g. stiffness and plasticity, are not taken into account.     

String structures and the path fibration of a group

We use the realisation of the universal bundle for the loop group as the path fibration of the group to investigate the string class, that is the obstruction to a loop group bundle lifting to a Kac-Moody group bundle. In the case that the loop group bundle is constructed by taking loops into a principal bundle we show that the classifying map is the holonomy around loops and give an explicit formula for the string class relating it to the Pontrjangin class of the principal bunble.     

Acidimetrie

Ohne Zusammenfassung     

Über Peanoflächen und ihren Rand

Ohne Zusammenfassung     

Zur Wertbestimmung von Perubalsam

Ohne Zusammenfassung     

Analyse der Luft

Ohne Zusammenfassung