The paper presents simple, physically plausible, but not physically based reflectance models for metals and other specular materials. So far there has been no metallic BRDF model that is easy to compute, suitable for fast importance sampling and is physically plausible. This gap is filled by appropriate modifications of the Phong, Blinn and the Ward models. The Phong and the Blinn models are kn...

Abst ract. We consider monotonic binary cellular automa ta on the lat tice ZP as models of systems capable of long-term memory, that is, capable of admitting multiple invariant configurat ions. Long-term memory in cellular aut omata can be robust in t he presence of noise, so that in a noisy environment the automaton may admit more than one stationary distribution on configurations. We examine ...

As Cook-Levin theorem showed, every NP problem can be reduced to SAT in polynomial time. In this paper I show a simpler and more efficent method to reduce some factorization problems to the satisfability of a boolean formula.

Though few scholars compare presidencies, a recent collection by John Carey and Matthew Shugart (1998) compares the use of the presidential executive decree power in several countries. In a similar vein, we examine the oft-neglected power of the presidential pardon in the United States and Russia. The power of presidents to grant pardons is typically unlimited, which fact alone makes it worthwh...

The text of this book is composed in Galliard with the display set in Garamond Old style and Stradivar-ius. Composition and manufacturing by the Maple-Vail Book Manufacturing Group. Book design by MarjorieJ. Flock.

A representation of finite-dimensional probabilistic models in terms of formally real Jordan algebras is obtained, in a strikingly easy way, from simple assumptions. This provides a framework in which real, complex and quaternionic quantum mechanics can be treated on an equal footing, and allows some (but not too much) room for other alternatives. This is based on earlier work (arXiv:1206:2897)...

OBJECTIVE To investigate whether early embryo cleavage kinetics were affected by type of culture media. METHODS In this prospective sibling-split study, 620 oocytes from 37 patients were randomly allocated into two groups: Cook group and Vitrolife group. Oocytes/embryos in Cook group, would be cultured with Cook sequential culture medium, while oocytes/embryos in Vitrolife group, would be cul...

We prove a time-space tradeoff for traversing undirected graphs, using a structured model that is a nonjumping variant of Cook and Rackoff’s “jumping automata for graphs.”