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Hierarchical residue number systems with small moduli and simple converters

Tadeusz Tomczak (2011)

International Journal of Applied Mathematics and Computer Science

In this paper, a new class of Hierarchical Residue Number Systems (HRNSs) is proposed, where the numbers are represented as a set of residues modulo factors of 2k ± 1 and modulo 2k . The converters between the proposed HRNS and the positional binary number system can be built as 2-level structures using efficient circuits designed for the RNS (2k-1, 2k, 2k+1). This approach allows using many small moduli in arithmetic channels without large conversion overhead. The advantages resulting from the...

Hierarchical text categorization using fuzzy relational thesaurus

Domonkos Tikk, Jae Dong Yang, Sun Lee Bang (2003)

Kybernetika

Text categorization is the classification to assign a text document to an appropriate category in a predefined set of categories. We present a new approach for the text categorization by means of Fuzzy Relational Thesaurus (FRT). FRT is a multilevel category system that stores and maintains adaptive local dictionary for each category. The goal of our approach is twofold; to develop a reliable text categorization method on a certain subject domain, and to expand the initial FRT by automatically added...

Hierarchies and reducibilities on regular languages related to modulo counting

Victor L. Selivanov (2009)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

We discuss some known and introduce some new hierarchies and reducibilities on regular languages, with the emphasis on the quantifier-alternation and difference hierarchies of the quasi-aperiodic languages. The non-collapse of these hierarchies and decidability of some levels are established. Complete sets in the levels of the hierarchies under the polylogtime and some quantifier-free reducibilities are found. Some facts about the corresponding degree structures are established. As an application,...

Hierarchies and reducibilities on regular languages related to modulo counting

Victor L. Selivanov (2008)

RAIRO - Theoretical Informatics and Applications

We discuss some known and introduce some new hierarchies and reducibilities on regular languages, with the emphasis on the quantifier-alternation and difference hierarchies of the quasi-aperiodic languages. The non-collapse of these hierarchies and decidability of some levels are established. Complete sets in the levels of the hierarchies under the polylogtime and some quantifier-free reducibilities are found. Some facts about the corresponding degree structures are established. As an application, we...

Hierarchies of weakly monotone restarting automata

František Mráz, Friedrich Otto (2005)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

It is known that the weakly monotone restarting automata accept exactly the growing context-sensitive languages. We introduce a measure on the degree of weak monotonicity and show that the language classes obtained in this way form strict hierarchies for the various types of deterministic and nondeterministic restarting automata without auxiliary symbols.

Hierarchies of weakly monotone restarting automata

František Mráz, Friedrich Otto (2010)

RAIRO - Theoretical Informatics and Applications

It is known that the weakly monotone restarting automata accept exactly the growing context-sensitive languages. We introduce a measure on the degree of weak monotonicity and show that the language classes obtained in this way form strict hierarchies for the various types of deterministic and nondeterministic restarting automata without auxiliary symbols.

High order edge elements on simplicial meshes

Francesca Rapetti (2007)

ESAIM: Mathematical Modelling and Numerical Analysis

Low order edge elements are widely used for electromagnetic field problems. Higher order edge approximations are receiving increasing interest but their definition become rather complex. In this paper we propose a simple definition for Whitney edge elements of polynomial degree higher than one. We give a geometrical localization of all degrees of freedom over particular edges and provide a basis for these elements on simplicial meshes. As for Whitney edge elements of degree one, the basis is...

Highly Undecidable Problems For Infinite Computations

Olivier Finkel (2009)

RAIRO - Theoretical Informatics and Applications

We show that many classical decision problems about 1-counter ω-languages, context free ω-languages, or infinitary rational relations, are Π½ -complete, hence located at the second level of the analytical hierarchy, and “highly undecidable”. In particular, the universality problem, the inclusion problem, the equivalence problem, the determinizability problem, the complementability problem, and the unambiguity problem are all Π½ -complete for context-free ω-languages or for infinitary rational...

Histoires de fichiers

Jean Françon (1978)

RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications

Hitting time of a corner for a reflected diffusion in the square

F. Delarue (2008)

Annales de l'I.H.P. Probabilités et statistiques

We discuss the long time behavior of a two-dimensional reflected diffusion in the unit square and investigate more specifically the hitting time of a neighborhood of the origin. We distinguish three different regimes depending on the sign of the correlation coefficient of the diffusion matrix at the point 0. For a positive correlation coefficient, the expectation of the hitting time is uniformly bounded as the neighborhood shrinks. For a negative one, the expectation explodes in a polynomial way...

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