共查询到20条相似文献,搜索用时 31 毫秒
1.
V. P. Zhukov 《Automation and Remote Control》2003,64(10):1544-1550
Consideration was given to the conditions for instability of the equilibrium states of a nonlinear nonautonomous dynamic systems obeying an ordinary vector differential equation of arbitrary order whose right-hand side
satisfies the following conditions: (i) for any t 0, div
0$$
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almost everywhere on the set H that is a neighborhood of the equilibrium point of the system
and (ii)
at any point
. The equilibrium states of such systems can be both stable and unstable. For one class of these systems, sufficient instability conditions were given, which enables one to carry out studies using only the information about the right-hand side of the system. 相似文献
2.
3.
I. V. Gaishun 《Automation and Remote Control》2002,63(11):1717-1723
A class of two-parameter discrete systems defined on the ring
of class of residues of integers
modulo m is studied. All solutions are shown to be periodic, stability conditions (equality of solutions to zero, beginning from a certain instant) and a controllability condition are formulated. Controllability is shown to guarantee stabilizability. 相似文献
4.
Franco Montagna 《Journal of Logic, Language and Information》2000,9(1):91-124
We investigate the variety corresponding to a logic (introduced in Esteva and Godo, 1998, and called there), which is the combination of ukasiewicz Logic and Product Logic, and in which Gödel Logic is interpretable. We present an alternative (and slightly simpler) axiomatization of such variety. We also investigate the variety, called the variety of
algebras, corresponding to the logic obtained from by the adding of a constant and of a defining axiom for one half. We also connect
algebras with structures, called f-semifields, arising from the theory of lattice-ordered rings, and prove that every
algebra
can be regarded as a structure whose domain is the interval [0, 1] of an f-semifield
, and whose operations are the truncations of the operations of
to [0, 1]. We prove that such a structure
is uniquely determined by
up to isomorphism, and we establish an equivalence between the category of
algebras and that of f-semifields. 相似文献
5.
Summary We study a class of congruences of strongly connected finite automata, called the group congruences, which may be defined in this way: every element fixing any class of the congruence induces a permutation on this class. These congruences form an ideal of the lattice of all congruences of the automaton
and we study the group associated with the maximal group congruence (maximal induced group) with respect to the Suschkevitch group of the transition monoid of
. The transitivity equivalence of the subgroups of the automorphism group of
are found to be the group congruences associated with regular groups, which form also in ideal of the lattice of congruences of
. We then characterize the automorphism group of
with respect to the maximal induced group. As an application, we show that, given a group G and an automaton
, there exists an automaton whose automorphism group is isomorphic to G and such that the quotient by the automorphism congruence is
. 相似文献
6.
The population dynamics model
, was considered. For this model with uniform distribution of delays
and a
n = 0, nonnegativeness and convexity of the sequence a
k (0 k n) was shown to be the sufficient stability condition. Therefore, there is no need to constrain the reproduction rate and the mean delay
. 相似文献
7.
We consider the modified conjugate gradient procedure for solving A
=
in which the approximation space is based upon the Krylov space associated with A
1/p
and
, for any integer p. For the square-root MCG (p=2) we establish a sharpened bound for the error at each iteration via Chebyshev polynomials in
. We discuss the implications of the quickly accumulating effect of an error in
in the initial stage, and find an error bound even in the presence of such accumulating errors. Although this accumulation of errors may limit the usefulness of this method when
is unknown, it may still be successfully applied to a variety of small, almost-SPD problems, and can be used to jump-start the conjugate gradient method. Finally, we verify these theoretical results with numerical tests. 相似文献
8.
We present results of computational experiments with an extension of the Perceptron algorithm by a special type of simulated annealing. The simulated annealing procedure employs a logarithmic cooling schedule
, where
is a parameter that depends on the underlying configuration space. For sample sets S of n-dimensional vectors generated by randomly chosen polynomials
, we try to approximate the positive and negative examples by linear threshold functions. The approximations are computed by both the classical Perceptron algorithm and our extension with logarithmic cooling schedules. For
and
, the extension outperforms the classical Perceptron algorithm by about 15% when the sample size is sufficiently large. The parameter was chosen according to estimations of the maximum escape depth from local minima of the associated energy landscape.
相似文献
9.
We consider the complexity of concept learning in various common models for on-line learning, focusing on methods for proving lower bounds to the learning complexity of a concept class. Among others, we consider the model for learning with equivalence and membership queries. For this model we give lower bounds on the number of queries that are needed to learn a concept class
in terms of the Vapnik-Chervonenkis dimension of
, and in terms of the complexity of learning
with arbitrary equivalence queries. Furthermore, we survey other known lower bound methods and we exhibit all known relationships between learning complexities in the models considered and some relevant combinatorial parameters. As it turns out, the picture is almost complete. This paper has been written so that it can be read without previous knowledge of Computational Learning Theory. 相似文献
10.
Let
be a finite field withq elements and
a rational function over
. No polynomial-time deterministic algorithm is known for the problem of deciding whetherf induces a permutation on
. The problem has been shown to be in co-R
co-NP, and in this paper we prove that it is inR
NP and hence inZPP, and it is deterministic polynomial-time reducible to the problem of factoring univariate polynomials over
. Besides the problem of recognizing prime numbers, it seems to be the only natural decision problem inZPP unknown to be inP. A deterministic test and a simple probabilistic test for permutation functions are also presented. 相似文献
11.
Let
be some set of orientations, that is,
. We consider the consequences of defining visibility based on curves that are monotone with respect to the orientations in
. We call such curves
-staircases. Two points p andq in a polygonP are said to
-see each other if an
-staircase fromp toq exists that is completely contained inP. The
-kernel of a polygonP is then the set of all points which
-see all other points. The
-kernel of a simple polygon can be obtained as the intersection of all {}-kernels, with
. With the help of this observation we are able to develop an
algorithm to compute the
-kernel of a simple polygon, for finite
. We also show how to compute theexternal
-kernel of a polygon in optimal time
. The two algorithms are combined to compute the (
-kernel of a polygon with holes in time
.This work was supported by the Deutsche Forschungsgemeinschaft under Grant No. Ot 64/5-4 and the Natural Sciences and Engineering Research Council of Canada and Information Technology Research Centre of Ontario. 相似文献
12.
The paper describes an improved algorithm for computing cohomologies of Lie (super)algebras. The original algorithm developed earlier by the author of this paper is based on the decomposition of the entire cochain complex into minimal subcomplexes. The suggested improvement consists in the replacement of the arithmetic of rational or integer numbers by a more efficient arithmetic of modular fields and the use of the relationship dim H
k(
p) dimH
k() between the dimensions of cohomologies over an arbitrary modular field
p = /p and the filed of rational numbers . This inequality allows us to rapidly find subcomplexes for which dimH
k(
p) > 0 (the number of such subcomplexes is usually not great) using computations over an arbitrary
p and, then, carry out all required computations over in these subcomplexes. 相似文献
13.
Terry Huntsberger 《Autonomous Robots》2001,11(3):341-346
Robotic missions beyond 2013 will likely be precursors to a manned habitat deployment on Mars. Such missions require robust control systems for long duration activities. Current single rover missions will evolve into deployment of multiple, heterogeneous cooperating robotic colonies. This paper describes the map-making memory and action selection mechanism of BISMARC (
iologically
nspired
ystem for
ap-based
utonomous
over
ontrol) that is currently under development at the Jet Propulsion Laboratory in Pasadena, CA (Huntsberger and Rose, Neutral Networks, 11(7/8):1497–1510). BISMARC is an integrated control system for long duration missions involving robots performing cooperative tasks. 相似文献
14.
M. A. Shepilov 《Cybernetics and Systems Analysis》1987,23(2):233-238
Conclusion The obvious deficiency of the method (1.3), (1.9) is the possible difficulty of the operation
. In connection with this one can note that all the above given statements remain valid if the number
is replaced by some positive lower bound of |f(t
k
,x)| on
.In computational methods, the presence of the Lipschitz constant is considered as a deficiency. In connection with this we can note that the Lipschitz constant L can be replaced by any of its upper estimates. For example, for a differentiable function f(z) one can take
.Translated from Kibernetika, No. 2, pp. 71–74, March–April, 1987. 相似文献
15.
In this paper we deepen Mundici's analysis on reducibility of the decision problem from infinite-valued ukasiewicz logic
to a suitable m-valued ukasiewicz logic
m , where m only depends on the length of the formulas to be proved. Using geometrical arguments we find a better upper bound for the least integer m such that a formula is valid in
if and only if it is also valid in
m. We also reduce the notion of logical consequence in
to the same notion in a suitable finite set of finite-valued ukasiewicz logics. Finally, we define an analytic and internal sequent calculus for infinite-valued ukasiewicz logic. 相似文献
16.
A novel optimal order optimal resource parallel multibody algorithm with general system applicability is derived directly from the sequential recursive
methods and the most recent developments in recursive constraint treatments. This new Recursive Coordinate Reduction Parallelism (RCRP) is the first optimal order
parallel direct method with a sequential implementation that is exactly the efficient
algorithm. Consequently, the RCRP sets new benchmarks for performance over a wide range of problem size and parallel resources. Comparisons to existing methods also demonstrate that the RCRP is presently the best general parallel method. 相似文献
17.
Composing the Carlet map with the inverse Gray map, a new family of cyclic quaternary codes is constructed from 5-cyclic
-codes. This new family of codes is inspired by the quaternary Shanbag–Kumar–Helleseth family, a recent improvement on the Delsarte–Goethals family. We conjecture that these
-codes are not linear. As applications, we construct families of low-correlation quadriphase and biphase sequences. 相似文献
18.
Summary Asynchronous two-dimensional iterative arrays of automata will be introduced where the underlying automata are not of Moore-type but of Mealy-type. We will prove that there exists a Mealy automaton,
, with only two states and one input and output for each of its four distinguished directions, such that any given Mealy-automaton can be realized by an iterative array with only
for its component-machines. It is known that loop-free nets cannot be as powerful as Mealy automata; however, we will show that any Mealy automaton can be realized by a network, N, with very restrictive component machines, where no signal may pass a loop in N. Using this fact asynchronous iterative arrays can be built up with one component machine,
such that any given Mealy automaton can be realized under the restriction that no signal passes a loop more than once.
contains only four states and one input and output for each direction. 相似文献
19.
New optimal control problems are considered for distributed systems described by elliptic equations with conjugate conditions and a quadratic minimized function. Highly accurate computational discretization schemes are constructed for the case where a feasible control set
coincides with the full Hilbert space
of controls. 相似文献
20.
Let a linear homogeneous ordinary differential equation with polynomial coefficients over a field
be given. For a singular point of the equation, the fundamental system of formal solutions that contain a finite number of power series with coefficients belonging to the algebraic extension of
can be constructed by known algorithms. In this paper, an algorithm is suggested for construction of a space of formal solutions such that all series containing in these solutions have m-hypergeometric coefficients. The implementation of the algorithm in the computer algebra system Maple is discussed. 相似文献