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First test of stochastic growth theory for Langmuir waves in Earth's foreshock

GEOPHYSICAL RESEARCH LETTERS 1997年第4期24卷 369-372页

作者： Cairns, IH Robinson, PA UNIV SYDNEY SCH PHYSSYDNEYNSW 2006AUSTRALIA

This paper presents the first test of whether stochastic growth theory (SGT) can explain the detailed characteristics of Langmuir-like waves in Earth's foreshock. A period with unusually constant solar wind magnetic field is analyzed. The observed distributions P (log E) of wave fields E for two intervals with relatively constant spacecraft location (DIFF) are shown to agree well with the fundamental prediction of SGT, that P (log E) is Gaussian in log E. This stochastic growth can be accounted for semi-quantitatively in terms of standard foreshock beam parameters and a model developed for interplanetary type III bursts. Averaged over the entire period with large variations in DIFF, the P (log E) distribution is a power-law with index similar to -1;this is interpreted in terms of convolution of intrinsic, spatially varying P (log E) distributions with a probability function describing ISEE's residence time at a given DIFF. Wave data from this interval thus provide good observational evidence that SGT can sometimes explain the clumping, burstiness, persistence, and highly variable fields of the foreshock Langmuir-like waves.

关键词： Iii radio-sources Bow shock Electron foreshock Frequency Upstream Decay growth theory probability functions Langmuir Upstream waves variable field theories RADIO SOURCES

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A RANDOM NP-COMPLETE PROBLEM FOR INVERSION OF 2D CELLULAR-AUTOMATA

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THEORETICAL COMPUTER SCIENCE 1995年第1期148卷 19-32页

作者： DURAND, B ENS LYON INFORMAT PARALLELISME LAB CNRS 46 ALLEE ITALIE F-69364 LYON 07 FRANCE

In this paper, we prove the co-RNP-completeness (RNP = Random NP) of the following decision problem: ''Given a 2-dimensional cellular automaton A, is A reversible when restricted to finite configurations extending a given row?'' In order to prove this result, we introduce a polynomial reduction from problems concerning finite tilings into problems concerning cellular automata. Then we add to the sets and cellular automata probability functions and we prove that these problems are not only co-NP-complete, but co-RNP-complete too.

关键词： Cellular automata Ribonucleoproteins tile setting Decision problem probability functions WWOX gene Automata Inversion

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IMAGE-RESTORATION USING A LORENTZIAN probability MODEL

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JOURNAL OF MODERN OPTICS 1995年第7期42卷 1367-1376页

作者： LETTINGTON, AH HONG, QH JJ Thomson Physical Laboratory University of Reading Whiteknights PO Box 220 Reading RG6 2AF England

The distribution of edge values for an image of a general scene often has a sharp peak with a long tail. This property, which can be well described by a Lorentzian probability function, has been used to develop an efficient nonlinear image restoration algorithm for reducing the various artifacts that often arise in the restored images. The algorithm starts with a Wiener filter solution which is used to model the edge image by the Lorentzian function so that the likelihood of the image can be estimated. A nonlinear correction term is then introduced which increases this image likelihood under the mean square error criterion. This process ensures that the resulting image retains its sharpness while reducing the noise and ringing artifacts. An iterative procedure has been developed to implement this method. Computer simulated results show that the algorithm is robust in reducing artifacts and easily implemented. The algorithm also possesses a superresolution capability due to the highly nonlinear property of the correction term.

关键词： algorithms correction of nonlinearity edge image probability functions correct entry image restoration algorithm Image Artifacts mean-square error criterion

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BINARY CLASSIFICATION BY STOCHASTIC NEURAL NETS

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IEEE TRANSACTIONS ON NEURAL NETWORKS 1995年第2期6卷 488-491页

作者： NADAS, A IBM Research Division IBM Thomas J. Watson Research Center Yorktown Heights NY USA

We classify points in R(d) (feature vectors) by functions related to feedforward artificial neural networks (ANN's). These functions, dubbed ''stochastic neural nets,'' arise in a natural way from probabilistic as well as statistical considerations. The probabilistic idea is to define a classifying bit locally by using the sign of a hidden state-dependent noisy linear function of the feature vector as a new;d + 1st coordinate of the vector. This d + 1-dimensional distribution is approximated by a mixture distribution. The statistical idea-is that the approximating mixtures, and hence the a posteriori class probability functions (stochastic neural nets) defined by them, can be conveniently trained either by maximum likelihood or by a Bayes criterion through the use of an appropriate Expectation-Maximization (EM) algorithm.

关键词： probability functions Eigenvector maximum likelihood Stochastic expectation-maximisation algorithm Neural network

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CONDITIONALS, probability, AND NONTRIVIALITY

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JOURNAL OF PHILOSOPHICAL LOGIC 1995年第5期24卷 455-467页

作者： MORGAN, CG MARES, ED VICTORIA UNIV WELLINGTON DEPT PHILOSOPHYWELLINGTONNEW ZEALAND

We show that the implicational fragment of intuitionism is the weakest logic with a non-trivial probabilistic semantics which satisfies the thesis that the probabilities of conditionals are conditional probabilities. We also show that several logics between intuitionism and classical logic also admit non-trivial probability functions which satisfy that thesis. On the other hand, we also prove that very weak assumptions concerning negation added to the core probability conditions with the restriction that probabilities of conditionals are conditional probabilities are sufficient to trivialize the semantics.

关键词： probability functions semiotics Semantics probability Theses Formal logic Conditional Negation Restriction Conditional probability intuitionism

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SIMULATION OF MICROPOPULATIONS IN EPIDEMIOLOGY - TUTORIAL-2 - ANALYTIC FORMS OF EVENT PROBABILITIES - A SERIES OF TUTORIALS ILLUSTRATED BY CORONARY HEART-DISEASE MODELS

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INTERNATIONAL JOURNAL OF BIO-MEDICAL COMPUTING 1994年第2期37卷 139-149页

作者： ACKERMAN, E National Micropopulation Simulation Resource Health Computer Sciences Box 511 UMHC University of Minnesota 420 Delaware Street SE Minneapolis MN 55455 USA

This is the second in a series of tutorials concerning the simulation of micropopulation models to support epidemiological research. The series emphasizes techniques that are included in studies at the National Micropopulation Simulation Resource at the University of Minnesota. For pedagogic purposes, applications to coronary heart disease models are used to illustrate the principles and methodologies employed. All of the models presented are implemented using available software. Both interpretation of the results of survey and surveillance data, and the simulation for predictive purposes of micropopulation models, depend upon the form chosen to represent the probability of the occurrence of an event associated with coronary heart disease. Four different forms are discussed;each can be used to represent the probability of transfer from the healthy state to one of the disease states or, in other words, the probability of occurrence of an event of interest. These four forms are by no means all-inclusive;rather they are one that are convenient to use with micropopulation simulation models and that exhibit a variety of the different possibilities.

关键词： SIMULATION MICROPOPULATION RISKS STOCHASTIC MODEL CHRONIC DISEASE MODEL probability functions

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THE DIMENSIONALITY OF SPACE-TIME IN A EINSTEIN-YANG-MILLS THEORY

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NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA A-NUCLEI PARTICLES AND FIELDS 1991年第4期104卷 469-474页

作者： LI, XZ ZHONG, Y East China Institute for Theoretical Physics 200237 China

In this paper, the wormhole effect is discussed in order to investigate whether it can lead to the derivation of the dimensionality of space-time. In a Einstein-Yang-Mills theory, the peak of the probability function leads to the explanation of the spontaneous compactification down to a four-dimensional space-time and vanishing four-dimensional cosmological constant, i.e. the observable space-time must be four-dimensional and flat.

关键词： probability functions derivation Spacetime wormhole theories Yang-Mills theory four-dimensional

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COUNTEREXAMPLES IN AB PERCOLATION

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JOURNAL OF PHYSICS A-MATHEMATICAL AND GENERAL 1989年第2期22卷 185-191页

作者： LUCZAK, T WIERMAN, JC UNIV MINNESOTA INST MATH & ITS APPLICATMINNEAPOLISMN 55455 JOHNS HOPKINS UNIV DEPT MATH SCIBALTIMOREMD 21218

Halley (1983) conjectured that the AB percolation probability function attains its maximum at p=1/2, and that consequently infinite AB percolation is impossible on a bipartite graph whose standard site percolation critical probability is greater than 1/2. The authors produce counterexamples that demonstrate that both conjectures are false. In fact, for any positive integer N, a graph may be constructed which has at least N AB percolation transitions.

关键词： Bipartite graph POLD4 gene probability functions POLE4 gene Counter example False Percolation Greater than Conjecture

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CALCULATING TIME-DEPENDENT PERFORMANCE-MEASURES FOR THE M/M/1 QUEUE

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IEEE TRANSACTIONS ON COMMUNICATIONS 1989年第10期37卷 1102-1104页

作者： ABATE, J WHITT, W AT&T BELL LABS MURRAY HILLNJ 07974

Methods are discussed for computing transient performance measures for the M/M/1 queue. These performance measures are often expressed in terms of modified Bessel functions without any discussion about computation. In fact, a common expression for the probability transition function of the M/M/1 queue length process has an infinite sum of modified Bessel functions. For actually generating numbers, however, it is convenient to use numerical integration with associated integral representations, as was first pointed out by P.M. Morse (Oper. Res., vol.3, p.255-61, 1955).

关键词： modified Bessel function probability functions PLXNB2 gene Infinite sum Numerical integration Queue BESSEL functions

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THE GENERAL-FORM OF REPRESENTATION OF WALL REGION OF A TURBULENT BOUNDARY-LAYER

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WARME UND STOFFUBERTRAGUNG-THERMO AND FLUID DYNAMICS 1989年第6期24卷 375-379页

作者： ROGACKI, G 1. Institute of Chemical and Process Engineering Technical University of ?ód? ul. Wólczańska 175 90-924 ?ód? Poland

On the basis of a formal similarity between turbulent momentum, heat/mass flux and probability function a concept of turbulent flux density distribution has been proposed. It has been shown that the characteristic bell shape of this distribution is almost the same, irrespective of the turbulence model from which it was calculated, and can reveal the structure of the turbulent boundary layer, especially the influence of molecularPr orSc number. This concept may also be used to test consistency and to compare differently formulated models of turbulent transport.

关键词： Turbulent Flow wall probability functions representations flux density distribution turbulent boundary layer Consistency (Measurement) boundary layer turbulence models consistency

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