We consider 3D consistent systems of six independent quad-equations assigned to the faces a cube. The well-known classification quad-equations, so-called ABS-list, is included in this situation. extension these equations whole lattice Z^3 possible by reflecting cubes. For every quad-equation we will give at least one system leading B\"acklund transformation and zero-curvature representation whi...

We formalize a combinatorial principle, called the 3XOR principle, due to Feige, Kim and Ofek [14], as a family of unsatisfiable propositional formulas for which refutations of small size in any propositional proof system that possesses the feasible interpolation property imply an efficient deterministic refutation algorithm for random 3SAT with n variables and Ω(n) clauses. Such small size ref...

The topic of this paper is optimized shading and lighting systems which consist of planar fins arranged along the edges of a quad-dominant base mesh, that mesh itself covering a reference surface. Such an arrangement can be observed e.g. in the Kogod courtyard roof designed by Foster + Partners for the National Portrait Gallery in Washington DC (Fig. 1): A reference surface consisting of three ...

A sweeping algorithm can generate hexahedral meshes by sweeping an all-quad mesh on the source surface to the target surface. For one-toone sweeping, the most difficult thing is to generate an all-quad mesh on the target surface which has the same mesh connectivity as that of the source surface. The traditional method is to use the affine transformation, like translation, rotation, scaling or c...

QUAD stream cipher uses multivariate polynomial systems. It has provable security based on the computational hardness assumption. More specifically, the security of QUAD depends on hardness of solving non-linear multivariate systems over a finite field, and it is known as an NP-complete problem. However, QUAD is slower than other stream ciphers, and an efficient implementation, which has a redu...

In this work we study the question of how much data is required in order for classical X and X charts with estimated control limits to perform essentially like charts with the true control limits. The results indicate that using estimated control limits results in charts on which the events that individual points exceed control limits are dependent events, and that one result of this dependence...

This research aims to develop collaborative language learning systems based on social and cognitive presence for learning settings out of class, and evaluate their effects on learning attitude and performance. The main purpose of this system is focusing on the building of a learning community, therefore the Community of Inquiry (CoI) framework suggested by Garrison, Anderson, and Archer (2000) ...

Zusammenfassung: Der Beitrag befasst sich mit einem möglichen Betriebsmodell für den Einsatz von VoIP im DFN-Umfeld. Im Rahmen eines Projekts der Partner T-Systems, Cisco, DFN-Verein und Universität Hannover/RRZN wird untersucht, wie ein von einem externen Dienstleister betriebener VoIP-Dienst – hier von TSystems angeboten und mit Komponenten von Cisco realisiert – umgesetzt werden kann. Neben ...

‎the aim of this paper is to study the convergence of solutions of the‎ ‎following second order difference inclusion‎ ‎begin{equation*}begin{cases}exp^{-1}_{u_i}u_{i+1}+theta_i exp^{-1}_{u_i}u_{i-1} in c_ia(u_i),quad igeqslant 1 u_0=xin m‎, ‎quad‎ ‎underset{igeqslant 0}{sup} d(u_i,x)

one of the most fundamental features of digital image and the basic steps in image processing, analysis, pattern recognition and computer vision is the edge of an image where the preciseness and reliability of its results will affect directly on the comprehension machine system made objective world. several edge detectors have been developed in the past decades, although no single edge detector...