Displaying 1641 – 1660 of 4973

Showing per page

Edon- ( 256 , 384 , 512 ) – an efficient implementation of Edon- family of cryptographic hash functions

Danilo Gligoroski, Svein Johan Knapskog (2008)

Commentationes Mathematicae Universitatis Carolinae

We have designed three fast implementations of a recently proposed family of hash functions Edon– . They produce message digests of length n = 256 , 384 , 512 bits and project security of 2 n 2 hash computations for finding collisions and 2 n hash computations for finding preimages and second preimages. The design is not the classical Merkle-Damgård but can be seen as wide-pipe iterated compression function. Moreover the design is based on using huge quasigroups of orders 2 256 , 2 384 and 2 512 that are constructed by using only bitwise...

Efficiency of automata in semi-commutation verification techniques

Gérard Cécé, Pierre-Cyrille Héam, Yann Mainier (2008)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Computing the image of a regular language by the transitive closure of a relation is a central question in regular model checking. In a recent paper Bouajjani et al. [IEEE Comput. Soc. (2001) 399–408] proved that the class of regular languages L – called APC – of the form j L 0 ...

Efficiency of automata in semi-commutation verification techniques

Gérard Cécé, Pierre-Cyrille Héam, Yann Mainier (2007)

RAIRO - Theoretical Informatics and Applications

Computing the image of a regular language by the transitive closure of a relation is a central question in regular model checking. In a recent paper Bouajjani et al. [IEEE Comput. Soc. (2001) 399–408] proved that the class of regular languages L – called APC – of the form UjL0,jL1,jL2,j...Lkj,j, where the union is finite and each Li,j is either a single symbol or a language of the form B* with B a subset of the alphabet, is closed under all semi-commutation relations R. Moreover a recursive...

Efficiency-conscious propositionalization for relational learning

Filip Železný (2004)

Kybernetika

Systems aiming at discovering interesting knowledge in data, now commonly called data mining systems, are typically employed in finding patterns in a single relational table. Most of mainstream data mining tools are not applicable in the more challenging task of finding knowledge in structured data represented by a multi-relational database. Although a family of methods known as inductive logic programming have been developed to tackle that challenge by immediate means, the idea of adapting structured...

Efficient calculation of sensitivities for optimization problems

Andreas Kowarz, Andrea Walther (2007)

Discussiones Mathematicae, Differential Inclusions, Control and Optimization

Sensitivity information is required by numerous applications such as, for example, optimization algorithms, parameter estimations or real time control. Sensitivities can be computed with working accuracy using the forward mode of automatic differentiation (AD). ADOL-C is an AD-tool for programs written in C or C++. Originally, when applying ADOL-C, tapes for values, operations and locations are written during the function evaluation to generate an internal function representation....

Efficient calculation of the Reed-Muller form by means of the Walsh transform

Piotr Porwik (2002)

International Journal of Applied Mathematics and Computer Science

The paper describes a spectral method for combinational logic synthesis using the Walsh transform and the Reed-Muller form. A new algorithm is presented that allows us to obtain the mixed polarity Reed-Muller expansion of Boolean functions. The most popular minimisation (sub-minimisation) criterion of the Reed-Muller form is obtained by the exhaustive search of all the polarity vectors. This paper presents a non-exhaustive method for Reed-Muller expansions. The new method allows us to build the...

Efficient computation of addition chains

F. Bergeron, J. Berstel, S. Brlek (1994)

Journal de théorie des nombres de Bordeaux

The aim of this paper is to present a unifying approach to the computation of short addition chains. Our method is based upon continued fraction expansions. Most of the popular methods for the generation of addition chains, such as the binary method, the factor method, etc..., fit in our framework. However, we present new and better algorithms. We give a general upper bound for the complexity of continued fraction methods, as a function of a chosen strategy, thus the total number of operations required...

Efficient generation of 3D surfel maps using RGB-D sensors

Artur Wilkowski, Tomasz Kornuta, Maciej Stefańczyk, Włodzimierz Kasprzak (2016)

International Journal of Applied Mathematics and Computer Science

The article focuses on the problem of building dense 3D occupancy maps using commercial RGB-D sensors and the SLAM approach. In particular, it addresses the problem of 3D map representations, which must be able both to store millions of points and to offer efficient update mechanisms. The proposed solution consists of two such key elements, visual odometry and surfel-based mapping, but it contains substantial improvements: storing the surfel maps in octree form and utilizing a frustum culling-based...

Currently displaying 1641 – 1660 of 4973