Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 6

Liczba wyników na stronie
first rewind previous Strona / 1 next fast forward last
Wyniki wyszukiwania
w słowach kluczowych:  degeneracy
help Sortuj według:

help Ogranicz wyniki do:
first rewind previous Strona / 1 next fast forward last
Keystreams of a degenerate stream cipher can be generated by another stream cipher of less bits, and recursive description of stream ciphers is useful in cryptanalysis. Two algorithms are proposed based on directed graphs informing whether each pair of bits are related in the state transition: One tests two categories of degenerate synchronous additive stream ciphers, particularly for realistic stream ciphers with sparse transition equations; the other finds a recursive description of a given stream cipher. Specially, the latter algorithm has to balance the efficiency and the number of sequences for a recursive description, and a sufficient condition is given to test degeneracy based on the recursive description.
The unified formalism for description of acoustic and optic properties is developed for directions close to degeneracies in absorbing crystals. The absorption splits a conical degeneracy which causes topological transformations in polarization and geometrical features of degenerate branches. Polarization ellipses distributions gain singularities at the degeneracy points characterized by the Poincaré indices n = ±1/4. The slowness surfaces acquire lines of self-intersection connecting the split degeneracy points where the wedge of intersection has infinitely sharp tips. Geometrical and polarization singularities due to absorption create non-trivial features in conical refraction. For any direction of propagation in the vicinity of the split axes the ray velocity precesses along the universal cone of refraction. Kinematics of this precession appreciably depends on the propagation direction. Conditions for experimental observation of the predicted effects are discussed.
In this paper, we discuss how changes in the coefficients matrix of piecewise linear fractional programming problems affect the non-degenerate optimal solution. We consider separate cases when changes occur in the coefficients of the basic and non-basic variables and derive bounds for each perturbation, while the optimal solution is invariant. We explain that this analysis is a generalization of the sensitivity analysis for LP, LFP and PLP. Finally, the results are described by some numerical examples.
Necessary and sufficient conditions for the pointwise completeness and pointwise degeneracy of the standard and positive hybrid linear systems described by the general model are established. It is shown that the standard general model is always pointwise complete and it is not pointwise degenerated and the positive general model is pointwise complete if and only if its matrix A2 is diagonal.
Content available remote A note on zeros, output-nulling subspaces and zero-dynamics in MIMO LTI systems
In a standard multi-input, multi-output linear time invariant (MIMO LTI) continuous-time system S9A,B,C) the classical notion of the Smith zeros does not characterize fully the output-zeroing problem nor the zero dynamics. The question how this notion can be extended and related to the state-space methods is discussed. Nothing is assumed about the ralationship of the number of inputs to the number of outputs nor about the normal rank of the underlying system matrix. The proposed extension treats multivariable zeros as the triples. Such a treatment is strictly connected with the output zeroing problem and in that spirit the zeros can be easily interpreted even in the degenerate case.
Content available remote Information Dynamics of Cellular Automata I -An Algebraic Study
Information dynamics of cellular automata(CA) is studied using polynomials over finite fields. The information about the uncertainty of cell states is expressed by an indeterminate X called information variable and its dynamics is investigated by extending CA to CA[X] whose cell states are polynomials in X. For the global configuration of extended CA[X], new notions of completeness and degeneracy are defined and their dynamical properties are investigated. A theorem is proved that completeness equals non-degeneracy. With respect to the reversibility, we prove that a CA is reversible, if and only if its extension CA[X] preserves the set of complete configurations. Information dynamics of finite CAs and linear CAs are treated in the separate sections. Decision problems are also referred.
first rewind previous Strona / 1 next fast forward last
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.