662 research outputs found
Sort by
Modularity and Regularity in Neural Networks Produced with Assembler Encoding
No full textThe main focus of the paper is on the ability of the neuro-evolutionary method called Assembler Encoding to repeatedly use the information includedin a genotype and to construct modular and/or regular neural networks. Itreports experiments whose the main goal was to test whether the method iscapable of adjusting topology of neural networks to a modular and regularproblem. In the experiments, the task of Assembler Encoding was to evolveneuro-controllers responsible for balancing two or three inverted pendulumsinstaled on separate carts. Since both the carts and the pendulums wereidentical the task of neuro-controllers could be performed by means ofmodular/regular neural networks
Volume 19 (2) 2013
Get PDFPoznańHamiltonian trajectories are strictly time-reversible. Any time series of Hamiltonian coordinates f q g satisfying Hamilton’s motion equations will likewise satisfy them when played “backwards”, with the corresponding momenta changing signs : f +p
Percolation in Systems Containing Ordered Elongated Objects
No full textWe studied the percolation and jamming of elongated objects using the Random Sequential Adsorption (RSA)technique. The objects were represented by linear sequences of beads forming needles. The positions of the beads wererestricted to vertices of two-dimensional square lattice. The external field that imposed ordering of the objects was introducedinto the model. The percolation and the jamming thresholds were determined for all systems under consideration.The influence of the chain length and the ordering on both thresholds was calculated and discussed. It was shown that fora strongly ordered system containing needles the ratio of percolation and jamming thresholds cp=cj is almost independenton the needle length d
Computer Experiments with Mersenne Primes
No full textWe have calculated on the computer the sum BM of reciprocals of first 47 known Mersenne primes with the accuracy of over 12000000 decimal digits. Next we developed BM into the continued fraction and calculated geometricalmeans of the partial denominators of the continued fraction expansion of BM . We get values converging to the Khinchin’s constant. Next we calculated the n-th square roots of the denominators of the n-th convergents of these continued fractions obtaining values approaching the Khinchin-Lèvy constant. These two results suggests that the sum of reciprocals of all Mersenne primes is irrational, supporting the common belief that there is an infinity of the Mersenne primes. For comparison we have done the same procedures with a slightly modified set of 47 numbers obtaining quite different results. Next we investigated the continued fraction whose partial quotients are Mersenne primes and we argue that it should be transcendental
Three-zonal Wall Function for k-e Turbulence Models
No full textMost commercially available wall functions for k-e turbulence models base on the two-zonal near-wall flowdivision assumption. Viscous and log-law sublayers are distinguished. In this article the three-zonal wall function conceptwith a buffer sublayer is developed. The aim of this new wall function is to improve the mean streamwise U+ velocity profile.The proposed wall function is validated on backward-facing step experimental data. Physical implications of the modelperformance are also discussed
A Resilience Parameter Model Generated by a Compound Distribution
No full textIn this paper, we shall attempt to extend the generalized exponential geometric distribution of Silva et al. [1]. The new four-parameter distribution also generalizes the Weibull-geometric distribution of Barreto-Souza et al. [2],exponentiated Weibull, and several other lifetime distributions as special cases. A useful characteristic of the new distribution is that its failure rate function can have different shapes. We first study certain basic distributional properties of the new distribution and provide closed form expressions for its moment generating function and moments. General expressions are also obtained for the order statistics densities and stress-strength parameter. Our findings happen to enfold several known results as special cases. The model parameters are estimated by the maximum likelihood method and the Fisher information matrix is discussed. Finally, the model is applied to a real data set and its advantage over some rival models is illustrated
Formulation and Solution of Space-Time Fractional KdV-Burgers Equation
No full textThe space-time fractional KdV-Burgers equation has been derived using the semi-inverse method and Agrawal’s variational method. The modified Riemann-Liouville definition is used for the fractional differential operators. The derived fractional equation is solved using the fractional sub-equation method
Cellular Automata Simulations for the System of Two-Level Atoms Placed in Two-Dimensional Cavity
No full textIn this paper, using one of the most effective simulation methods, namely the cellular automata formalism, we simulate the dynamics of a system which is composed of a large number of two-level atoms placed in a two-dimensional cavity. We suppose additionally that the cavity is confined by four semi-transparent “mirrors”. We show that similarly to the one-dimensional case, several interesting effects including the molasses effect occur in the considered system