检索结果-内蒙古大学图书馆

PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS 2003年第1-2期327卷 111-114页

作者： Arizmendi, CM Sanchez, JR Family, F Univ Mar del Plata Fac Ingn Dept Fis RA-7600 Mar Del Plata Argentina Emory Univ Dept Phys Atlanta GA 30322 USA

Thermal ratchets are Brownian models where time correlated nonequilibrium fluctuations interacting with a spatially asymmetric potential are sufficient conditions to give rise to rectified transport. The nonequilibrium fluctuations act as a source of negentropy (physical information). Data compression techniques are used here to quantify the transfer of information in thermal ratchet motion. (C) 2003 Elsevier B.V. All rights reserved.

关键词： thermal ratchets information transfer algorithmic complexity

来源：评论

学校读者我要写书评

暂无评论

Zipping thermal ratchets

Zipping thermal ratchets

引用

13th Conference on Nonequilibrium Statistical Mechanics and Nonlinear Physics

作者： Arizmendi, CM Sanchez, JR Family, F Univ Mar del Plata Fac Ingn Dept Fis RA-7600 Mar Del Plata Argentina Emory Univ Dept Phys Atlanta GA 30322 USA

关键词： thermal ratchets information transfer algorithmic complexity

来源：评论

学校读者我要写书评

暂无评论

Blind channel identification of dispersive CDMA channels

Blind channel identification of dispersive CDMA channels

引用

International Conference on Neural Networks and Signal Processing

作者： Li, XD Yu, JB Univ Elect Sci & Technol China Coll Elect Engn Chengdu 610054 Sichuan Peoples R China

ISBN: (纸本)0780377028

A new blind identification method based on signal subspace estimation is proposed. With the dispersive CDMA channel modeled as a multiple-input multipleoutput signal model, the impulse response of the multiuser's channels can be identified without training sequences. The method characterizes parallel processing and lower algorithmic complexity, hence it is suitable for high-rate CDMA communication system. The computational requirement of the algorithm is o(N-2), N being the size of the covariance matrix. The algorithm is locally convergent and the undesired stationary points are unstable. Monte-carlo simulations demonstrate the performance of the proposed methods in a channel identification context.

关键词： blind source separation code division multiple access transient response multiuser channels covariance matrices Monte Carlo methods blind channel identification dispersive CDMA channels signal subspace estimation multiple input multiple output signal model impulse response multiuser channels parallel processing algorithmic complexity CDMA communication system covariance matrix Monte-Carlo simulation code division multiple access

来源：评论

学校读者我要写书评

暂无评论

Predictability: a way to characterize complexity

引用

PHYSICS REPORTS-REVIEW SECTION OF PHYSICS LETTERS 2002年第6期356卷 367-474页

作者： Boffetta, G Cencini, M Falcioni, M Vulpiani, A Univ Turin Dipartimento Fis Gen I-10125 Turin Italy Unita Univ Turin Ist Nazl Fis Mat Turin Italy Max Planck Inst Phys Komplexer Syst D-01187 Dresden Germany Univ Roma La Sapienza Dipartimento Fis I-00185 Rome Italy Ist Nazl Fis Mat Unita Roma 1 Rome Italy

Different aspects of the predictability problem in dynamical systems are reviewed. The deep relation among Lyapunov exponents, Kolmogorov-Sinai entropy, Shannon entropy and algorithmic complexity is discussed. In particular, we emphasize how a characterization of the unpredictability of a system gives a measure of its complexity. Adopting this point of view, we review some developments in the characterization of the predictability of systems showing different kinds of complexity: from low-dimensional systems to high-dimensional ones with spatio-temporal chaos and to fully developed turbulence. A special attention is devoted to finite-time and finite-resolution effects on predictability, which can be accounted with suitable generalization of the standard indicators. The problems involved in systems with intrinsic randomness is discussed, with emphasis on the important problems of distinguishing chaos from noise and of modeling the system. The characterization of irregular behavior in systems with discrete phase space is also considered. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： predictability high-dimensional chaos algorithmic complexity turbulence

来源：评论

学校读者我要写书评

暂无评论

Entropy and complexity of finite sequences as fluctuating quantities

引用

BIOSYSTEMS 2002年第1-3期64卷 23-32页

作者： Jiménez-Montaño, MA Ebeling, W Pohl, T Rapp, PE Univ Americas Puebla Dept Fis & Matemat Puebla 72820 Mexico Univ Veracruzana Fac Fis & Inteligencia Artificial Xalapa 91000 Veracruz Mexico Humboldt Univ Inst Phys D-10115 Berlin Germany Med Coll Penn & Hahnemann Univ Dept Physiol Philadelphia PA 19129 USA

The paper is devoted to the analysis of digitized sequences of real numbers and discrete strings, by means of the concepts of entropy and complexity. Special attention is paid to the random character of these quantities and their fluctuation spectrum. As applications, we discuss neural spike-trains and DNA sequences. We consider a given sequence as one realization of finite length of certain random process. The other members of the ensemble are defined by appropriate surrogate sequences and surrogate processes. We show that n-gram entropies and the context-free grammatical complexity have to be considered as fluctuating quantities and study the corresponding distributions. Different complexity measures reveal different aspects of a sequence. Finally, we show that the diversity of the entropy (that takes small values for pseudorandom strings) and the context-free grammatical complexity (which takes large values for pseudorandom strings) give, nonetheless, consistent results by comparison of the ranking of sample sequences taken from molecular biology, neuroscience, and artificial control sequences. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.

关键词： block entropies diversity of entropy algorithmic complexity spectrum of fluctuations spike trains DNA sequences

来源：评论

学校读者我要写书评

暂无评论

Uniquely colorable mixed hypergraphs

引用

DISCRETE MATHEMATICS 2002年第1-3期248卷 221-236页

作者： Tuna, Z Voloshin, V Zhou, HS Moldovan Acad Sci Inst Math & Comp Sci MD-2028 Kishinev Moldova Hungarian Acad Sci Inst Comp & Automat H-1111 Budapest Hungary Georgia State Univ Dept Math & Comp Sci Atlanta GA 30303 USA

A mixed hypergraph consists of two families of edges: the C-edges and D-edges. In a coloring, every C-edge has at least two vertices of the same color, while every D-edge has at least two vertices colored differently. The largest and smallest possible numbers of colors in a coloring are termed the upper and lower chromatic number, (chi) over bar and chi, respectively. A mixed hypergraph is called uniquely colorable if it has precisely one coloring apart from the permutation of colors. We begin a systematic study of uniquely colorable mixed hypergraphs. In particular, we show that every colorable mixed hypergraph can be embedded into some uniquely colorable mixed hypergraph;we investigate the role of uniquely colorable subhypergraphs being separators, study recursive operations (orderings and subset contractions) and unique colorings, and prove that it is NP-hard to decide whether a mixed hypergraph is uniquely colorable. We also discuss the weaker property where the mixed hypergoraph has a unique coloring with (chi) over bar colors and a unique coloring with chi colors, where (chi) over bar > chi. The class of these "weakly uniquely colorable" mixed hypergraphs contains all uniquely colorable graphs in the usual sense. (C) 2002 Elsevier Science B.V. All rights reserved.

关键词： coloring mixed hypergraphs lower (upper) chromatic number unique colorability algorithmic complexity

来源：评论

学校读者我要写书评

暂无评论

algorithmic complexity and stochastic properties of finite binary sequences

引用

COMPUTER JOURNAL 1999年第4期42卷 294-317页

作者： V'yugin, VV Russian Acad Sci Inst Informat Transmiss Problems Moscow 101447 Russia

This paper is a survey of concepts and results related to simple Kolmogorov complexity, prefix complexity and resource-bounded complexity, We also consider a new type of complexity-statistical complexity closely related to mathematical statistics, Unlike other discoverers of algorithmic complexityt. A. N. Kolmogorov's leading motive was developing on its basis a mathematical theory more adequately substantiating applications of probability theory, mathematical statistics and information theory, Kolmogorov wanted to deduce properties of a random object from its complexity characteristics without use of the notion of probability, In the first part of this paper me present several results in this direction. Though the subsequent development of algorithmic complexity and randomness tvas different, algorithmic complexity has successful applications in a traditional probabilistic framework, In the second part of the paper me consider applications to the estimation of parameters and the definition of Bernoulli sequences. All considerations have finite combinatorial character.

关键词： Computational complexity Algorithms Statistical methods Probability Random processes Kolmogorov complexity Bernoulli sequences Stochastic Processes complexity algorithmic complexity algorithms binary sequences Parameter estimation complexity classes Probability Theory Kolmogorov complexity Statistical methods

来源：评论

学校读者我要写书评

暂无评论

complexity of learning in artificial neural networks

引用

THEORETICAL COMPUTER SCIENCE 2001年第1-2期265卷 285-306页

作者： Engel, A Univ Magdeburg Inst Theoret Phys D-39016 Magdeburg Germany

Some basic issues in the statistical mechanics of learning from examples are reviewed. The approach of statistical physics is contrasted with the analysis of learning within the framework of mathematical statistics and the question of the algorithmic complexity of explicit learning prescriptions is addressed. Even in very simple learning scenarios, the typical properties of which can be analyzed in great quantitative detail by methods from statistical mechanics, the determination of a suitable hypothesis approximating the target rule may be an NP-complete problem. Some special learning setups are suggested as model systems for the comparison between the approaches of statistical mechanics and computer science to the theory of computationally hard problems. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： neural networks learning theory statistical mechanics algorithmic complexity

来源：评论

学校读者我要写书评

暂无评论

Rationally presented metric spaces and complexity - The spaces of uniformly continuous real functions over a compact interval

引用

THEORETICAL COMPUTER SCIENCE 2001年第1-2期250卷 265-332页

作者： Labhalla, S Lombardi, H Moutai, E Univ Marrakech Dept Math Maroc Morocco Univ Franche Comte Dept Math Math Lab F-25030 Besancon France

We define the notion of rational presentation of a complete metric space, in order to study metric spaces from the algorithmic complexity point of view. In this setting, we study some representations of the space C[0, 1] of uniformly continuous real functions over [0, 1] with the usual norm: \\f\\(infinity) = Sup{\f(x)\;0 less than or equal to x less than or equal to 1}. This allows us to have a comparison of global kind between complexity notions attached to these presentations. In particular, we get a generalization of Hoover's results concerning the Weierstrass approximation theorem in polynomial time. We get also a generalization of previous results on analytic functions which are computable in polynomial time. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： Espaces métriques Fonctions réelles Machine de Turing Circuit booléen Circuit semilinéaire binaire Circuit arithmétique Complexité algorithmique Théorème d'approximation de Weierstrass Classe de Gevrey Séries de Chebyshev Metric spaces Real functions Turing machine Boolean circuit Binary semi-linear circuit Arithmetic circuit algorithmic complexity Weierstrass approximation theorem Gevrey class Chebyshev series

来源：评论

学校读者我要写书评

暂无评论

Neural networks as sources of chaotic motor activity in ants and how complexity develops at the social scale

引用

INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS 2001年第6期11卷 1655-1664页

作者： Miramontes, O Sole, RV Goodwin, BC Univ Nacl Autonoma Mexico Inst Fis Dept Sistemas Complejos Mexico City 1000 DF Mexico Univ Politecn Cataluna Complex Syst Res Grp Dept Fis & Engn Nucl ES-08034 Barcelona Spain Santa Fe Inst Santa Fe NM 87501 USA Schumacher Coll Dartington TQ9 6EA Devon England

We discuss a Neural Network model generating activation signals for locomotion in ants. The signals are chaotic and so are the temporal patterns of spontaneous activations in single ants. Active ants are able to move and interact with other nest mates. This process of movement-interaction generates periodic pulses of activity once the number of individuals reaches a certain density value. An algorithmic complexity measure is used for identifying accurately the transition from chaos into order. Finally, an Iterated Function System analysis reveals the richness of dynamical behavior that emerges when ant colonies are self-poised near such a transition.

关键词： Ants complexity algorithmic complexity repetitive pulse Iterated Function System Neural network chaos Motor Activity Locomotion

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：