The integer groups of coinvariants associated to undecorated and decorated octagonal tilings are computed.

Disparity estimation is a very important operation in stereo image and video compression. However, existing disparity estimation algorithms require too large computation power. In this paper, we propose a fast disparity estimation algorithm for mesh-based stereo image and video compression with two-stage hybrid approach, which is names as Two Stage Iterative Block and Octagonal Matching algorit...

Quadtree and pyramid structures have attracted considerable attention in recent years. They are increasingly being applied to the fields of digital image and signal processing. As a result, the efficient embedding of these structures in VLSI arrays has become an important research topic. In this paper, we propose three schemes to embed either quadtrees or pyramids in a rectangular, hexagonal, o...

We study statistical properties of energy spectra of a tight-binding model on the twodimensional quasiperiodic Ammann-Beenker tiling. Taking into account the symmetries of finite approximants, we find that the underlying universal level-spacing distribution is given by the Gaussian orthogonal random matrix ensemble, and thus differs from the critical level-spacing distribution observed at the m...

Propagation properties of square, hexagonal and octagonal lattice photonic crystal fibers (PCFs) have been analyzed here for both stressed and unstressed conditions. The analysis has been carried out using finite element method. All types of PCFs are investigated here by varying number of air hole rings with same design and operating parameters. The results show that external stress causes PCFs...

We present almost linear area bounds for drawing complete trees on the octagonal grid. For 7-ary trees we establish an upper and lower bound of Θ(n1.129) and for ternary trees the bounds of O(n1.048) and Θ(n), where the latter needs edge bends. We explore the unit edge length and area complexity of drawing unordered trees on k-grids with k ∈ {4, 6, 8} and generalize the N P-hardness results of ...

Details are given of the theory of magnetic symmetry in quasicrystals, which has previously only been outlined. A practical formalism is developed for the enumeration of spin point groups and spin space groups, and for the calculation of selection rules for neutron scattering experiments. The formalism is demonstrated using the simple, yet non-trivial, example of magnetically ordered octagonal ...

Neighborhoods and neighborhood sequences play important roles in several branches of pattern analysis. In earlier papers in Z only certain special (e.g. periodic or octagonal) sequences were investigated. In this paper we study neighborhood sequences which are either ultimately periodic or allow at every neighborhood to do nothing at no cost. We give finite procedures and descriptive theoretica...

Random tilings are interesting as idealizations of atomistic models of quasicrystals and for their connection to problems in combinatorics and algorithms. Of particular interest is the tiling entropy density, which measures the relation of the number of distinct tilings to the number of constituent tiles. Tilings by squares and 45 rhombi receive special attention as presumably the simplest mode...

Negative staining of isolated nuclear envelopes by phosphotungstate shows that the nuclear pores are octagonal rather than circular. Pores of the same shape and approximately the same width, 663 +/- 5 A, were demonstrated in the newt, Triturus, the frog, Rana, and the starfish, Henricia. The outer and inner diameters of the annulus associated with each pore are respectively greater and less tha...