共查询到20条相似文献,搜索用时 31 毫秒
2.
Richardson splitting applied to a consistent system of linear equations Cx = b with a singular matrix C yields to an iterative method xk+1 = Axk + b where A has the eigenvalue one. It is known that each sequence of iterates is convergent to a vector x* = x* (x0) if and only if A is semi-convergent. In order to enclose such vectors we consider the corresponding interval iteration
with (|[A]|) = 1 where |[A]| denotes the absolute value of the interval matrix [A]. If |[A]| is irreducible we derive a necessary and sufficient criterion for the existence of a limit
of each sequence of interval iterates. We describe the shape of
and give a connection between the convergence of (
) and the convergence of the powers
of [A].Dedicated to Professor G. Mae on the occasion of his 65th birthday 相似文献
3.
R. F. Streater 《Open Systems & Information Dynamics》2004,11(4):359-375
Let H0 be a selfadjoint operator such that Tr
is of trace class for some
, and let
denote the set of ε-bounded forms, i.e.,
for some
0 $$" align="middle" border="0">
. Let χ := Span
. Let
denote the underlying set of the quantum information manifold of states of the form
. We show that if Tr
,
Presented at the 36th Symposium on Mathematical Physics, ‘Open Systems & Quantum Information’, Toruń, Poland, June 9-12, 2004. 相似文献
1. | the map Φ,
| |
2. | The Orlicz space defined by Φ is the tangent space of at ρ0; its affine structure is defined by the (+1)-connection of Amari | |
3. | The subset of a ‘hood of ρ0, consisting of p-nearby states (those obeying for some 1$$" align="middle" border="0"> ) admits a flat affine connection known as the (-1) connection, and the span of this set is part of the cotangent space of | |
4. | These dual structures extend to the completions in the Luxemburg norms. |
4.
Agent Communication Languages (ACLs) have been developed to provide a way for agents to communicate with each other supporting
cooperation in Multi-Agent Systems (MAS). In the past few years many ACLs have been proposed for MAS and new standards are
emerging such as the ACL developed by the Foundation for Intelligent Physical Agents (FIPA). Despite these efforts, an important
issue in the research on ACLs is still open and concerns how these languages should deal with failures of agents in asynchronous MAS. The Fault Tolerant Agent Communication Language (
-
) presented in this paper addresses this issue dealing with crash failures of agents.
-
provides high-level communication primitives which support a fault-tolerant anonymous interaction protocol designed for open
MAS. We present a formal semantics for
-
and a formal specification of the underlying agent architecture. This formal framework allows us to prove that the ACL satisfies
a set of well defined knowledge-level programming requirements. To illustrate the language features we show how
-
can be effectively used to write high-level executable specifications of fault tolerant protocols, such as the Contract Net
one. 相似文献
5.
6.
The Sum of D Small-Bias Generators Fools Polynomials of Degree D 总被引:1,自引:1,他引:0
Emanuele Viola 《Computational Complexity》2009,18(2):209-217
7.
On Defining Integers And Proving Arithmetic Circuit Lower Bounds 总被引:1,自引:1,他引:0
Peter Bürgisser 《Computational Complexity》2009,18(1):81-103
8.
9.
Remco Duits Michael Felsberg Gösta Granlund Bart ter Haar Romeny 《International Journal of Computer Vision》2007,72(1):79-102
Inspired by the early visual system of many mammalians we consider the construction of-and reconstruction from- an orientation
score
as a local orientation representation of an image,
. The mapping
is a wavelet transform
corresponding to a reducible representation of the Euclidean motion group onto
and oriented wavelet
. This wavelet transform is a special case of a recently developed generalization of the standard wavelet theory and has the
practical advantage over the usual wavelet approaches in image analysis (constructed by irreducible representations of the
similitude group) that it allows a stable reconstruction from one (single scale) orientation score. Since our wavelet transform
is a unitary mapping with stable inverse, we directly relate operations on orientation scores to operations on images in a
robust manner.
Furthermore, by geometrical examination of the Euclidean motion group
, which is the domain of our orientation scores, we deduce that an operator Φ on orientation scores must be left invariant
to ensure that the corresponding operator
on images is Euclidean invariant. As an example we consider all linear second order left invariant evolutions on orientation
scores corresponding to stochastic processes on G. As an application we detect elongated structures in (medical) images and automatically close the gaps between them.
Finally, we consider robust orientation estimates by means of channel representations, where we combine robust orientation
estimation and learning of wavelets resulting in an auto-associative processing of orientation features. Here linear averaging
of the channel representation is equivalent to robust orientation estimation and an adaptation of the wavelet to the statistics
of the considered image class leads to an auto-associative behavior of the system.
The Netherlands Organization for Scientific Research is gratefully acknowledged for financial support. This work has been
supported by EC Grant IST-2003-004176 COSPAL. 相似文献
10.
Evgeny Dantsin Vladik Kreinovich Alexander Wolpert Gang Xiang 《Reliable Computing》2006,12(4):273-280
In statistical analysis of measurement results, it is often beneficial to compute the range V of the population variance when we only know the intervals of possible values of the xi. In general, this problem is NP-hard; a polynomialtime algorithm is known for the case when the measurements are sufficiently accurate, i.e., when for all In this paper, we show that we can efficiently compute V under a weaker (and more general) condition . 相似文献
11.
Escape analysis of object-oriented languages approximates the set of objects which do not escape from a given context. If we take a method as context, the non-escaping objects can be allocated on its activation stack;
if we take a thread, Java synchronisation locks on such objects are not needed. In this paper, we formalise a basic escape
domain
as an abstract interpretation of concrete states, which we then refine into an abstract domain
which is more concrete than
and, hence, leads to a more precise escape analysis than
. We provide optimality results for both
and
, in the form of Galois insertions from the concrete to the abstract domains and of optimal abstract operations. The Galois
insertion property is obtained by restricting the abstract domains to those elements which do not contain garbage, by using an abstract garbage collector. Our implementation of
is hence an implementation of a formally correct escape analyser, able to detect the stack allocatable creation points of
Java (bytecode) applications. 相似文献
12.
13.
In this paper, we use the concepts of {1} - and {2} -inverse of a matrix to construct such a Krawczyk-like operator as
where Y Rnxm, and A Rmxn satisfies YAY = Y. We also construct a generalized Krawczyk-Moore algorithm using this operator. Our main result is that, under the conditions
there is a unique solution of Yf(x) = 0 on X
{x + R(Y)} , and the generalized Krawczyk-Moore algorithm converges to this solution at least linearly. 相似文献
14.
Every Linear Threshold Function has a Low-Weight Approximator 总被引:1,自引:1,他引:0
Rocco A. Servedio 《Computational Complexity》2007,16(2):180-209
15.
Hierarchical matrices (
-matrices) approximate matrices in a data-sparse way, and the approximate arithmetic for
-matrices is almost optimal. In this paper we present an algebraic approach for constructing
-matrices which combines multilevel clustering methods with
-matrix arithmetic to compute the
-inverse,
-LU, and the
-Cholesky factors of a matrix. Then the
-inverse,
-LU or
-Cholesky factors can be used as preconditioners in iterative methods to solve systems of linear equations. The numerical
results show that this method is efficient and greatly speeds up convergence compared to other approaches, such as JOR or
AMG, for solving some large, sparse linear systems, and is comparable to other
-matrix constructions based on Nested Dissection. 相似文献
16.
An algorithm that performs asynchronous backtracking on distributed
, with dynamic ordering of agents is proposed,
. Agents propose reorderings of lower priority agents and send these proposals whenever they send assignment messages. Changes
of ordering triggers a different computation of
. The dynamic ordered asynchronous backtracking algorithm uses polynomial space, similarly to standard
. The
algorithm with three different ordering heuristics is compared to standard
on randomly generated
. A Nogood-triggered heuristic, inspired by dynamic backtracking, is found to outperform static order
by a large factor in run-time and improve the network load. 相似文献
17.
The generalized Zakharov system (ZS) couples a dispersive field E (scalar or vectorial) and
nondispersive fields
with a propagating speed of
. In this paper, we extend our one-dimensional time-splitting spectral method (TSSP) for the generalized ZS into higher dimension.
A main new idea is to reformulate the multi-dimensional wave equations for the nondispersive fields into a first-order system
using a change of variable defined in the Fourier space. The proposed scheme TSSP is unconditionally stable, second-order
in time and spectrally accurate in space. Moreover, in the subsonic regime, it allows numerical capturing of the subsonic
limit without resolving the small parameters
. Numerical examples confirm these properties of this method 相似文献
18.
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$$
" align="middle" border="0">
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
19.
20.