13,251 research outputs found
Design principles of hardware-based phong shading and bump-mapping
The VISA+ hardware architecture is the first of a new generation of graphics accelerators designed primarily to render bump-, texture-, environment- and environment-bump-mapped polygons. This paper presents examples of the main graphical capabilities and discusses methods and simplifications used to create high quality images. One of the key concepts in the VISA+ design, the use of reflectance cubes, is predestined for environment mapping. In combination with bump- and texture-mapping it shows the strength of our new architecture. Furthermore it justifies some of the decisions made during simulation and development of the complex VISA+ architecture
Advanced ablation strategies for management of post-surgical atrial arrhythmias.
Post-surgical arrhythmias include a wide range of arrhythmias occurring late after cardiac surgery and represent a complex substrate for catheter ablation either because of extended scar and remodeling or because of limited access to the area of interest. Novel image integration and ablation tools have made the catheter ablation in this population both feasible and successful. We review a structured approach to catheter ablation of post-surgical atrial arrhythmias in various patient cohorts including the most common congenital heart defects
Proof of a generalized Geroch conjecture for the hyperbolic Ernst equation
We enunciate and prove here a generalization of Geroch's famous conjecture
concerning analytic solutions of the elliptic Ernst equation. Our
generalization is stated for solutions of the hyperbolic Ernst equation that
are not necessarily analytic, although it can be formulated also for solutions
of the elliptic Ernst equation that are nowhere axis-accessible.Comment: 75 pages (plus optional table of contents). Sign errors in elliptic
case equations (1A.13), (1A.15) and (1A.25) are corrected. Not relevant to
proof contained in pape
Acoustics of tachyon Fermi gas
We consider a Fermi gas of free tachyons as a continuous medium and find
whether it satisfies the causality condition. There is no stable tachyon matter
with the particle density below critical value and the Fermi momentum
that depends on the tachyon mass . The pressure
and energy density cannot be arbitrary small, but the situation is
not forbidden. Existence of shock waves in tachyon gas is also discussed. At
low density the tachyon matter remains stable but no shock wave
do survive.Comment: 14 pages, 2 figures (color
Randomly Driven Granular Fluids: collisional statistics and short scale structure
We present a molecular dynamics and kinetic theory study of granular
material, modeled by inelastic hard disks, fluidized by a random driving force.
The focus is on collisional averages and short distance correlations in the
non-equilibrium steady state, in order to analyze in a quantitative manner the
breakdown of molecular chaos, i.e. factorization of the two-particle
distribution function,
in a product of single particle ones, where
with and represents the position correlation. We have found that
molecular chaos is only violated in a small region of the two-particle phase
space , where there is a predominance of grazing collisions. The
size of this singular region grows with increasing inelasticity. The existence
of particle- and noise-induced recollisions magnifies the departure from mean
field behavior. The implications of this breakdown in several physical
quantities are explored.Comment: 28 pages, 16 figure
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