共查询到20条相似文献,搜索用时 15 毫秒
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Computational methods are described for effecting complete ligand field calculations, inclusive of spin-orbit coupling, on the strong-field {(cN)Sl'SaSl'L;l'b} basis. Plotter routines which subsequently execute complet e energy diagrams of Tanabe-Sugano type are presented. The procedures operate for all dN configurations, N = 1, 2, …, 9, and make full use of the point group symmetry of the system, G?SO(3). The relations employed for calculation of the matrix elements are listed and methods to obtain all required coefficients are given. The resulting diagrams are required for the interpretation of spectra and paramagnetic properties of dN systems. 相似文献
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This paper is concerned with the general problem of computer vision. That is, given a colored input picture, design a system which segments the objects in the scene and interprets them appropriately. During the past few years, we have been engaged in the development of a modular, data-driven computer vision system to achieve this goal. The details have appeared elsewhere, so here we have primarily emphasized the mechanism for updating the hypothesized region interpretations. This is achieved by means of a relaxation labeling process which has continuous access to a scene model describing the picture under consideration. 相似文献
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Volker Claus 《Acta Informatica》1981,16(2):139-160
Summary This paper investigates some problems which change their status from being unsolvable to solvable when varying the values of parameters. Let EMPTY(n, k) be the problem to decide for all rational probabilistic acceptors B with at most n states and k input symbols and for all rational numbers , whether the accepted language L(B,) is empty. It turns out that EMPTY(2, k) is solvable for all k, while EMPTY (9,9) and EMPTY (65,2) are not. Some problems of the theory of -rational power series are shown to be unsolvable, too, even for small values of the problemparameters. 相似文献
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A. Deppman O.A.P. TavaresS.B. Duarte E.C. de OliveiraJ.D.T. Arruda-Neto S.R. de PinaV.P. Likhachev O. Rodriguez J. MesaM. Gonçalves 《Computer Physics Communications》2002,145(3):385-394
We present an object oriented algorithm, written in the Java programming language, which performs a Monte Carlo calculation of the evaporation-fission process taking place inside an excited nucleus. We show that this nuclear physics problem is very suited for the object oriented programming by constructing two simple objects: one that handles all nuclear properties and another that takes care of the nuclear reaction. The MCEF code was used to calculate important results for nuclear reactions, and here we show examples of possible uses for this code. 相似文献
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《国际计算机数学杂志》2012,89(1-4):199-228
A machine model, which consists essentially of a finite state control and an array of counters with first-in-last-out access, is formulated and it is proved that, under certain restrictions, the class of languages accepted is identical to the class of developmental languages without interactions. 相似文献
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A.F. Ferrari 《Computer Physics Communications》2007,176(5):334-346
SusyMath is a Mathematica package for quantum superfield calculations. It defines a standard form to translate the correction to the effective action corresponding to a given supergraph into a Mathematica expression, which is then evaluated and simplified. Several functions for manipulations of these expressions are provided, and the package also has the ability to save the outcomes of its calculations in form.
Program summary
Title of program: SusyMathCatalogue identifier:ADYQ_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYQ_v1_0Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland, also at http://fma.if.usp.br/~alysson/SusyMathLicensing provisions: LGPL, CPC non-profit use licenseProgramming language: MathematicaPlatform: Any platform supporting Mathematica 4.0 or higherComputer tested on: PC (Athlon64 X2 +3800); 1 GB RAMOperating system under which the program has been tested: Linux (Debian 4.0); XOrg 7.0.22; Mathematica 5.2No. of lines in distributed program, including test data, etc.:42 472No. of bytes in distributed program, including test data, etc.:471 596Distribution format:tar.gzNature of the problem: Evaluate quantum corrections to the effective action of supersymmetric field theories, formulated in the superfield formalism, both in three- and four-spacetime dimensions.Solution method: A set of procedures for integration by parts, application of the algebra of covariant derivatives and Grassman integration, along with several auxiliary functions, is introduced.Restrictions: At the moment, the background field method is not implemented, but the system is designed to be further generalized.Running time: Depends on the complexity of the problem. From seconds for simpler one-loop diagrams to several hours for simple two-loop graphs. 相似文献12.
Surveys learning algorithms for recurrent neural networks with hidden units and puts the various techniques into a common framework. The authors discuss fixed point learning algorithms, namely recurrent backpropagation and deterministic Boltzmann machines, and nonfixed point algorithms, namely backpropagation through time, Elman's history cutoff, and Jordan's output feedback architecture. Forward propagation, an on-line technique that uses adjoint equations, and variations thereof, are also discussed. In many cases, the unified presentation leads to generalizations of various sorts. The author discusses advantages and disadvantages of temporally continuous neural networks in contrast to clocked ones continues with some "tricks of the trade" for training, using, and simulating continuous time and recurrent neural networks. The author presents some simulations, and at the end, addresses issues of computational complexity and learning speed. 相似文献
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Pavlovic V.I. Sharma R. Huang T.S. 《IEEE transactions on pattern analysis and machine intelligence》1997,19(7):677-695
The use of hand gestures provides an attractive alternative to cumbersome interface devices for human-computer interaction (HCI). In particular, visual interpretation of hand gestures can help in achieving the ease and naturalness desired for HCI. This has motivated a very active research area concerned with computer vision-based analysis and interpretation of hand gestures. We survey the literature on visual interpretation of hand gestures in the context of its role in HCI. This discussion is organized on the basis of the method used for modeling, analyzing, and recognizing gestures. Important differences in the gesture interpretation approaches arise depending on whether a 3D model of the human hand or an image appearance model of the human hand is used. 3D hand models offer a way of more elaborate modeling of hand gestures but lead to computational hurdles that have not been overcome given the real-time requirements of HCI. Appearance-based models lead to computationally efficient “purposive” approaches that work well under constrained situations but seem to lack the generality desirable for HCI. We also discuss implemented gestural systems as well as other potential applications of vision-based gesture recognition. Although the current progress is encouraging, further theoretical as well as computational advances are needed before gestures can be widely used for HCI. We discuss directions of future research in gesture recognition, including its integration with other natural modes of human-computer interaction 相似文献
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DSS evaluation may be either ex-post or ex-ante. In the former, evaluation focuses on determining the actual result of DSS implementation. In the latter, emphasis is on predicting the likely impact of DSS alternatives on a given task set or on estimating relationships between DSS characteristics and task set(s) performance. If a firm can, ex-ante, effectively estimate or predict the performance of varying DSS on arrays of tasks or task sets, then it can avoid costly DSS selection errors and gain competitive and strategic advantages. We outline a methodoloy for developing such information using the induced-value methodology of experimental economics. An example experiment is detailed and initial results are presented relating to one general DSS hypothesis and one implication derived from a specific theory of DSS portfolio selection. 相似文献
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The natural formulation of the elemental stiffness has proved a most significant interpretation of the elastic behaviour of an element, both from the physical and mathematical point of view. It yields not only concise and elegant matrix expressions for the elements — especially for simplex elements — but leads effortlessly to the non-linear effects associated with large displacements. In the present paper the basic idea is brought to a logical conclusion by the direct construction of the factorised form of the elemental and overall stiffness matrices from their natural stiffness roots. This technique is denoted as the natural factor formulation. It is believed that the new approach leads to a better understanding of the relevant error analysis so powerfully initiated by Rosanoff et al.; see e.g. [20]. The natural factor formulation may also be shown to retain more numerical information of the idealised physical system [21, 28]. Both static and dynamic problems are considered here. For additional information the reader is referred to [16]. 相似文献
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Giese TJ Gregersen BA Liu Y Nam K Mayaan E Moser A Range K Faza ON Lopez CS de Lera AR Schaftenaar G Lopez X Lee TS Karypis G York DM 《Journal of molecular graphics & modelling》2006,25(4):423-433
This work outlines a new on-line database of quantum calculations for RNA catalysis (QCRNA) available via the worldwide web at http://theory.chem.umn.edu/QCRNA. The database contains high-level density functional calculations for a large range of molecules, complexes and chemical mechanisms important to phosphoryl transfer reactions and RNA catalysis. Calculations are performed using a strict, consistent protocol such that a wealth of cross-comparisons can be made to elucidate meaningful trends in biological phosphate reactivity. Currently, around 2000 molecules have been collected in varying charge states in the gas phase and in solution. Solvation was treated with both the PCM and COSMO continuum solvation models. The data can be used to study important trends in reactivity of biological phosphates, or used as benchmark data for the design of new semiempirical quantum models for hybrid quantum mechanical/molecular mechanical simulations. 相似文献
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Isotonic separation is a supervised machine learning technique where classification is represented as a linear programming problem (LPP) with an objective of minimizing the number of misclassifications. It is computationally expensive to solve the LPP using traditional methods when the dataset grows. Evolutionary isotonic separation (EIS), a hybrid classification algorithm, is introduced to tackle this issue. Here, isotonic separation acts as a host architecture where evolutionary framework based on genetic algorithm is embedded in the training phase of the isotonic separation, to find an optimum or near-optimum solution for the LPP. Evolutionary framework deploys a newly introduced slack vector to find the feasible solution. It also employs a position-based crossover operator to obtain the optimum or near-optimum solution. Experimental studies are conducted on Wisconsin Breast Cancer dataset and a synthetic dataset. Experimental and statistical results show that EIS outperforms its predecessors and state of the art machine learning techniques in terms of accuracy. 相似文献
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A computer program for evaluating colour factors of QCD Feynman diagrams is presented, and illustrative examples on how to use the program to calculate nontrivial colour factors are given. The program and the discussion in this paper is based on a diagrammatic approach to colour factors. 相似文献
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Elsayed K. Elmaghraby 《Computer Physics Communications》2009,180(9):1694-1699
The present work focuses on a pre-equilibrium nuclear reaction code (based on the one, two and infinity hypothesis of pre-equilibrium nuclear reactions). In the PHASE-OTI code, pre-equilibrium decays are assumed to be single nucleon emissions, and the statistical probabilities come from the independence of nuclei decay. The code has proved to be a good tool to provide predictions of energy-differential cross sections. The probability of emission was calculated statistically using bases of hybrid model and exciton model. However, more precise depletion factors were used in the calculations. The present calculations were restricted to nucleon-nucleon interactions and one nucleon emission.
Program summary
Program title: PHASE-OTICatalogue identifier: AEDN_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEDN_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 5858No. of bytes in distributed program, including test data, etc.: 149 405Distribution format: tar.gzProgramming language: Fortran 77Computer: Pentium 4 and Centrino DuoOperating system: MS WindowsRAM: 128 MBClassification: 17.12Nature of problem: Calculation of the differential cross section for nucleon induced nuclear reaction in the framework of pre-equilibrium emission model.Solution method: Single neutron emission was treated by assuming occurrence of the reaction in successive steps. Each step is called phase because of the phase transition nature of the theory. The probability of emission was calculated statistically using bases of hybrid model [1] and exciton model [2]. However, more precise depletion factor was used in the calculations. Exciton configuration used in the code is that described in earlier work [3].Restrictions: The program is restricted to single nucleon emission and nucleon-nucleon interactions.Running time: 5-30 minutesReferences:- [1]
- M. Blann, Phys. Rev. Lett. 27 (1971) 337.
- [2]
- E. Gadioli, E.G. Erba, J.J. Hogan, Phys. Rev. C 16 (1977) 1404-1424.
- [3]
- E.K. Elmaghraby, Phys. Rev. C 78 (2008) 014601.