In this paper we summarize new and existing approaches for the semiautomatic image segmentation based on active contour models. In order to replace the manual segmentation of images of the medical research of the Center of Anatomy at the Georg August University of Göttingen we developed a user interface based on snakes. Due to the huge images (sometimes bigger than 100 megapixels) the research ...

A number of important computational problems in molecular biology, geology, speech recognition, and other areas, can be expressed as recurrences which have typically been solved with dynamic programming. By using more sophisticated data structures, and by taking advantage of further structure from the applications, we speed up the computation of several of these recurrences by one or two orders...

QUAD is a provable secure stream cipher based on multivariate polynomials which was proposed in 2006 by Berbain, Gilbert and Patarin [1]. In this paper we show how to speed up QUAD over GF(256) by a factor of up to 5.8. We get this by using structured systems of polynomials, in particular partially circulant polynomials and polynomials generated by a linear recurring sequence (LRS), instead of ...

We present a method for nding e cient instruction sequences for the Serpent S-boxes. Current implementations need many registers to store temporary variables, yet the common x86 processors only have 8 registers, of which even fewer are available for computations. The instructions are also destructive, replacing one input with the output. Alternative versions of the S-box instructions are presen...

In this work we present a highly efficient implementation of OpenMP tasks. It is based on a runtime infrastructure architected for data locality, a crucial prerequisite for exploiting the NUMA nature of modern multicore multiprocessors. In addition, we employ fast work-stealing structures, based on a novel, efficient and fair blocking algorithm. Synthetic benchmarks show up to a 6-fold increase...