We present a novel, compact bounding volume hierarchy, TSS BVH, for ray tracing subdivision surfaces computed by the Catmull-Clark scheme. We use Tetrahedron Swept Sphere (TSS) as a bounding volume to tightly bound limit surfaces of such subdivision surfaces given a user tolerance. Geometric coordinates defining our TSS bounding volumes are implicitly computed from the subdivided mesh via a sim...

This paper presents two concurrency control protocols for real-time object-oriented systems. One of the protocols (A ected Set Priority Ceiling Protocol) is designed for single-node systems, and the other (Distributed A ected Set Priorityt Ceiling Protocol) is designed for distributed systems. Both protocols combine features of semantic concurrency control for added concurrency, with priority c...

Alice and Bob want to know if two strings of length n are almost equal. That is, do they differ on at most a bits? Let 0 ≤ a ≤ n − 1. We show that any deterministic protocol, as well as any error-free quantum protocol (C∗ version), for this problem requires at least n− 2 bits of communication. We show the same bounds for the problem of determining if two strings differ in exactly a bits. We als...

Alice and Bob want to know if two strings of length n are almost equal. That is, do they differ on at most a bits? Let 0 ≤ a ≤ n − 1. We show that any deterministic protocol, as well as any error-free quantum protocol (C∗ version), for this problem requires at least n− 2 bits of communication. We show the same bounds for the problem of determining if two strings differ in exactly a bits. We als...

Alice and Bob want to know if two strings of length n are almost equal. That is, do they differ on at most a bits? Let 0 ≤ a ≤ n − 1. We show that any deterministic protocol, as well as any error-free quantum protocol (C∗ version), for this problem requires at least n− 2 bits of communication. We show the same bounds for the problem of determining if two strings differ in exactly a bits. We als...

We present a method for guaranteed collision detection with toleranced motions. The basic idea is to consider the motion as a curve in the 12-dimensional space of affine displacements, endowed with an object-oriented Euclidean metric, and cover it with balls. The associated orbits of points, lines, planes and polygons have particularly simple shapes that lend themselves well to exact and fast c...

A secure peer-to-peer communication over an insecure channel without any prior exchanged key can be established with the help of an authentication step to exchange a public key. Then, standard methods of public-key cryptography such as RSA can be used to communicate securely. In this work, we concentrate on message authentication protocols which require an extra authenticated channel. We start ...