Bauhaus University, Weimar

About: Bauhaus University, Weimar is a education organization based out in Weimar, Thüringen, Germany. It is known for research contribution in the topics: Finite element method & Isogeometric analysis. The organization has 1421 authors who have published 2998 publications receiving 104454 citations. The organization is also known as: Bauhaus-Universität Weimar & Hochschule für Architektur und Bauwesen.

A generalized God-object method for plausible finger-based interactions in virtual environments

Abstract: We generalize the six degree-of-freedom God-object approach to enable its use for multi-finger interactions in virtual environments. The connected finger phalanxes are modeled as multiple constrained God objects. The mutual interdependencies between multiple God objects are resolved using Gauss' principle of least constraint. This generalization of the God-object method allows us to avoid the penetration of multiple fingers and their phalanxes with objects within a physically simulated virtual world. Our observations indicate that the generalized God-object approach leads to plausible collision-free positions and motions of the phalanxes of the user's fingers during complex six degree-of-freedom manipulations, while artifacts such as artificial friction or a stuck hand are avoided.

Some Riemann boundary value problems in Clifford analysis

Abstract: In this paper, we mainly study the Rm (m>0) Riemann boundary value problems for functions with values in a Clifford algebra Cl(V3, 3). We prove a generalized Liouville-type theorem for harmonic functions and biharmonic functions by combining the growth behaviour estimates with the series expansions for k-monogenic functions. We obtain the result under only one growth condition at infinity by using the integral representation formulas for harmonic functions and biharmonic functions. By using the Plemelj formula and the integral representation formulas, a more generalized Liouville theorem for harmonic functions and biharmonic functions are presented. Combining the Plemelj formula and the integral representation formulas with the above generalized Liouville theorem, we prove that the Rm (m>0) Riemann boundary value problems for monogenic functions, harmonic functions and biharmonic functions are solvable. Explicit representation formulas of the solutions are given. Copyright © 2009 John Wiley & Sons, Ltd.

Slide Attacks on a Class of Hash Functions

Abstract: This paper studies the application of slide attacks to hash functions. Slide attacks have mostly been used for block cipher cryptanalysis. But, as shown in the current paper, they also form a potential threat for hash functions, namely for sponge-function like structures. As it turns out, certain constructions for hash-function-based MACs can be vulnerable to forgery and even to key recovery attacks. In other cases, we can at least distinguish a given hash function from a random oracle. To illustrate our results, we describe attacks against the Grindahl -256 and Grindahl -512 hash functions. To the best of our knowledge, this is the first cryptanalytic result on Grindahl -512. Furthermore, we point out a slide-based distinguisher attack on a slightly modified version of RadioGatun . We finally discuss simple countermeasures as a defense against slide attacks.