University of Winnipeg

About: University of Winnipeg is a education organization based out in Winnipeg, Manitoba, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 3235 authors who have published 6413 publications receiving 150564 citations. The organization is also known as: U of W.

Optic flow and depth perception

Abstract: The field of depth recovery from optic flow has recently experienced much growth, both on the theoretical and on the empirical fronts. Unfortunately, the theoretical results are not as widely known to perception workers as they might be. This article gives a simple analysis of the information for depth present in optic flow. It also reviews the psychophysical results for depth recovery from motion. These results are discussed with reference to the theoretical analysis and to relevant computer algorithms for depth recovery.

A theory of presumption for everyday argumentation

Abstract: The paper considers contemporary models of presumption in terms of their ability to contribute to a working theory of presumption for argumentation. Beginning with the Whatelian model, we consider its contemporary developments and alternatives, as proposed by Sidgwick, Kauffeld, Cronkhite, Rescher, Walton, Freeman, Ullmann-Margalit, and Hansen. Based on these accounts, we present a picture of presumptions characterized by their nature, function, foundation and force. On our account, presumption is a modal status that is attached to a claim and has the effect of shifting, in a dialogue, a burden of proof set at a local level. Presumptions can be analysed and evaluated inferentially as components of rule-based structures. Presumptions are defeasible, and the force of a presumption is a function of its normative foundation. This picture seeks to provide a framework to guide the development of specific theories of presumption.

Transformations of real-time finite-temperature Feynman rules.

Abstract: We consider transformations of the 2[times]2 propagator matrix in real-time finite-temperature field theory, resulting in transformed [ital n]-point functions. As special cases of such a transformation we examine the Keldysh basis, the retarded/advanced [ital RA] basis, and a Feynman-like [ital F[bar F]] basis, which differ in this context as to how economically'' certain constraints on the original propagator matrix elements are implemented. We also obtain the relation between some of these real-time functions and certain analytic continuations of the imaginary-time functions. Finally, we compare some aspects of these bases which arise in practical calculations.