In this paper the natural boundary reduction for some elliptic boundary value problems with concave angle domains and its natural boundary element methods are investigated. Natural integral equations and Poisson integ...
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In this paper the natural boundary reduction for some elliptic boundary value problems with concave angle domains and its natural boundary element methods are investigated. Natural integral equations and Poisson integral formulae are given. A finite element methods of natural integral equations are discussed in details. The convergence of approximate solutions and their error estimates are obtained. Some numerical experiments are presented to demonstrate the performance of the method and our estimates. As an application, we present the coupling of FEM and natural boundary element.
This paper presents a quantitative analysis of patterns visible in high-resolution NDVI images obtained from airborne remote sensing. Attention focuses on the use of wavelets to distinguish patterns of interest for pr...
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This paper presents a quantitative analysis of patterns visible in high-resolution NDVI images obtained from airborne remote sensing. Attention focuses on the use of wavelets to distinguish patterns of interest for precision agriculture at several scales. A general procedure for analyzing these images is presented and applied to a single field in the Netherlands, monitored at four different days during one growing season. Wavelet decomposition of the images is capable to reveal and quantify patterns present at different resolution levels and directions and to filter information that is less relevant for precision agriculture applications. Wavelet approximation with different wavelet functions is useful within the backward-looking and the forward-looking approaches of decision-making by allowing adaptation of the analysis to the characteristics of the available images or maps and to the possibilities of the existing site-specific inst.uments, respectively.
In a systematic study of thalamocortical relay neuron responses to sinusoidal current injection [J. Neurophysiol. 83 (1), 588], we found that the Fourier fundamental of tonic responses was regularly phase advanced dur...
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A math.matical model of diffusion of vaporized interacting metal molecules in a fireproof material is considered. The model is based on microscopic kinetic equations describing the process under condition of a strongl...
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A math.matical model of diffusion of vaporized interacting metal molecules in a fireproof material is considered. The model is based on microscopic kinetic equations describing the process under condition of a strongly non-homogeneous temperature field. A two-dimensional structure is examined, where the inner hot surface acts as the source of metal vapour and the outer surface - as a cooler. Due to interaction between metal molecules, a phase transition (condensation) proceeds near the outer surface. A conservative, monotonous, and absolutely stable difference scheme is developed on the basis of a special exponential substitution for the concentration of molecules. Results of 2D numerical experiments in non-steady state are presented.
In this paper we present an algorithm that estimates dense planar-parallax motion from multiple uncalibrated views of a 3D scene. This generalizes the "plane + parallax" recovery methods to more than two fra...
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Inspired from biochemistry and DNA computing, we introduce several variants of controlled concatenation of strings and languages: a finite set of pairs of strings is given and two arbitrary strings are concatenated on...
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Inspired from biochemistry and DNA computing, we introduce several variants of controlled concatenation of strings and languages: a finite set of pairs of strings is given and two arbitrary strings are concatenated only when among their substrings (scattered substrings, of various forms) we can find a pair in this control set. Five types of non-iterated and iterated (like Kleene closure) conditional concatenations are considered. The closure properties of abstract families of languages (hence also of families in the Chomsky hierarchy) are settled. They are similar to the closure properties under usual concatenation and Kleene closure: A representation of regular languages in terms of these operations (and a coding) is also given. Then, we use the new concatenation operations as basic operations in Chomsky grammars: rewriting a nonterminal means concatenating a new string with the strings to the left and the right of that nonterminal, hence restricted concatenations can be used. Context-free grammars working in this restricted manner can generate non-context-free languages;in one case, characterizations of recursively enumerable or of context-sensitive languages are obtained, depending on using or not erasing rules. Some topics for further research are also suggested.
Computational complexity of algorithms for solving problems has been at the heart of theoretical computerscience. Traditionally, the computational cost of an algorithm is estimated by "counting" operations ...
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Computational complexity of algorithms for solving problems has been at the heart of theoretical computerscience. Traditionally, the computational cost of an algorithm is estimated by "counting" operations combinatorially depending on the algorithm. We present a very different method for estimating cost of solving problem, incorporating ideas from information theory. Algorithms can be viewed as "search" procedures on the input (output) space. This naturally makes computational cost of algorithm as function of "entropy" of input (output) distribution. The relation of computational complexity and "entropy" of distribution depends on the particular "operations" used by algorithm to solve problem. This particular mapping between computational scale and "entropy" scale is independent of problem. We demonstrate the use of this method in classical "searching" and "sorting" problems. We work out many different searching and sorting algorithms' complexity using this method. In process, we also come up with new algorithms to solve some cases of searching and sorting that are aware of input distribution.
We present two algorithms which align flexible protein structures. Both apply efficient structural pattern detection and graph theoretic techniques. The FlexProt algorithm simultaneously detects the hinge regions and ...
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