In the paper three vector algorithms (with original data structures and no nearest neighbour lists) for Molecular Dynamics simulation are compared and their timings presented. The timings have been obtained on ETA 10-...
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In the paper three vector algorithms (with original data structures and no nearest neighbour lists) for Molecular Dynamics simulation are compared and their timings presented. The timings have been obtained on ETA 10-P*108 and IBM 3090/150E (with Vector Facility) computers as well as on several microprocessors (e.g. MOTOROLA MC68020/68881, INTEL i80386/387, i486 and INMOS TRANSPUTER T800).
computational procedures are described for the efficient estimation of the fixed and random parameters in multilevel random coefficient linear models. The estimation procedure is based on iterative generalised least s...
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computational procedures are described for the efficient estimation of the fixed and random parameters in multilevel random coefficient linear models. The estimation procedure is based on iterative generalised least squares. A number of special cases are described and the procedure is implemented within a general purpose statistical package.
The past decade has seen substantial research on exact inference for contingency tables, both in terms of developing new analyses and developing efficient algorithms for computations. Coupled with concomitant improvem...
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Novel dynamic random-dot displays representing a rotating cylinder or a noise-field were used to investigate the perception of structure from motion (SFM) in humans. The finite lifetimes of the points allowed the stud...
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Novel dynamic random-dot displays representing a rotating cylinder or a noise-field were used to investigate the perception of structure from motion (SFM) in humans. The finite lifetimes of the points allowed the study of spatiotemporal characteristics with smoothly moving stimuli. In one set of experiments subjects had to detect the change from the unstructured motion to the appearance of the cylinder in a reaction time task. In another set of experiments subjects had to distinguish these two stimuli in a two-alternative forced-choice task. The two major findings were: (1) a relatively constant point lifetime threshold (50-85 msec) for perceiving structure from motion. This This threshold is similar to the threshold for estimating velocity and suggests that velocity measurements are used to process SFM;(2) long reaction times for detecting structuring (approximately 1 sec). The build-up of performance with time and with increasing numbers of points reflects a process of temporal and spatial integration. We propose that this integration is achieved through the generation of a surface representation of the object. Information from single features on the object appears to be used to interpolate a surface between these local measurements allowing the system to improve perception over extended periods of time even though each feature is present only briefly. Selective masking of the stimulus produced characteristic impairments which suggest that both velocity measurements and surface interpolation are global processes.
The paper describes a sequential MD algorithm in which distances between particles are evaluated using fixed point arithmetics. Errors introduced by the method are estimated. Some simulation timings as well as fluctua...
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The paper describes a sequential MD algorithm in which distances between particles are evaluated using fixed point arithmetics. Errors introduced by the method are estimated. Some simulation timings as well as fluctuations of the total energy are compared to the results obtained using floating point arithmetics.
Checker board periodic boundary conditions for molecular simulation are proposed. They represent a simple geometric transformation of the well known periodic boundary conditions formulae for variety of periodic and re...
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This paper presents computational algorithms for the de- sign of an innovative spectral analyzer using the Wigner distribution. algorithms for the kernel generation, kernel transformation, and dis- crete Hilbert trans...
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This paper presents computational algorithms for the de- sign of an innovative spectral analyzer using the Wigner distribution. algorithms for the kernel generation, kernel transformation, and dis- crete Hilbert transform are discussed. Design strategies are focused on achieving high time-frequency resolution, precision, flexibility, and computational efficiency. Experiments show that spectral analysis using the Wigner distribution yields significantly improved results for non- stationary signals.
In this paper, we consider a class of optimal control problems involving continuous inequality state constraints. This class of optimal control problems can be solved using the technique developed in a paper by Goh an...
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In this paper, we consider a class of optimal control problems involving continuous inequality state constraints. This class of optimal control problems can be solved using the technique developed in a paper by Goh and Teo, where a simple constraint transcription is used to convert continuous inequality state constraints into equivalent equality terminal state constraints. However, that constraint transcription has the disadvantage that the equality terminal state constraints so obtained do not satisfy the usual constraint qualification. Thus, convergence is not guaranteed and some oscillation may exist in numerical computation. The aim of this paper is to use a new constraint transcription together with the concept of control parametrization to devise a new computational algorithm for solving this general class of constrained optimal control problems. This new algorithm is much more stable numerically, as we have successfully overcome the above-mentioned disadvantages.
In this paper, we review some methods which are designed to solve equality constrained minimization problems by following the trajectory defined by a system of ordinary differential equations. The numerical performanc...
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In this paper, we review some methods which are designed to solve equality constrained minimization problems by following the trajectory defined by a system of ordinary differential equations. The numerical performance of a number of these methods is compared with that of some popular sequential quadratic programming algorithms. On a set of eighteen difficult test problems, we observe that several of the ODE methods are more successful than any of the SQP techniques. We suggest that these experimental results indicate the need for research both to analyze and develop new ODE techniques and also to strengthen the currently available SQP algorithms.
In this paper, we review briefly some methods for minimizing a functionF(x), which proceed by follwoing the solution curve of a system of ordinary differential equations. Such methods have often been thought to be una...
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In this paper, we review briefly some methods for minimizing a functionF(x), which proceed by follwoing the solution curve of a system of ordinary differential equations. Such methods have often been thought to be unacceptably expensive; but we show, by means of extensive numerical tests, using a variety of algorithms, that the ODE approach can in fact be implemented in such a way as to be more than competitive with currently available conventional techniques.
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