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 $n_T$ and the Fermi momentum $k_F<\sqrt{\frac 32}m$ that depends on the tachyon mass $m$. The pressure $P$ and energy density $E$ cannot be arbitrary small, but the situation $P>E$ is not forbidden. Existence of shock waves in tachyon gas is also discussed. At low density $n_T<n<3.45n_T$ 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, $f^{(2)}(x_1,x_2) \simeq \chi f^(1)(x_1) f^{(1)}(x_2)$ in a product of single particle ones, where $x_i = \{{\bf r}_i, {\bf v}_i \}$ with $i=1,2$ and $\chi$ represents the position correlation. We have found that molecular chaos is only violated in a small region of the two-particle phase space $\{x_1,x_2\}$, 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