The scalar difference equation xn+1 = fn(xn, xn−1, · · · , xn−k) may exhibit symmetries in its form that allow for reduction of order through substitution or a change of variables. Such form symmetries can be defined generally using the semiconjugate relation on a group which yields a reduction of order through the semiconjugate factorization of the difference equation of order k + 1 into equat...

The paper presents the results of 3D FDTD modeling of a 915 MHz cylindrical structure with a spherical load (fruit). Three different configurations of the loops exciting the TM01l mode are analyzed. The coupling is shown not to be sensitive to the load’s temperature and to the type of the fruit.

We define a finite-differences derivative operation, on a non uniformly spaced partition, which has the exponential function as an exact eigenvector. We discuss some properties of this operator and we propose a definition for the components of a finite-differences momentum operator. This allows us to perform exact discrete calculations.

We suggest a modification of the operator exponential method for the numerical solving the difference linear initial boundary value problems. The scheme is based on the representation of the difference operator for given boundary conditions as the perturbation of the same operator for periodic ones. We analyze the error, stability and efficiency of the scheme for a model example of the one-dime...

We present an infrared adaptation of the Cluster Red-Sequence method. We modify the two filter technique of Gladders & Yee (2000) to identify clusters based on their R − [3.6] color. We apply the technique to the 4 degree Spitzer First Look Survey and detect 123 clusters spanning the redshift range 0.09 < z < 1.4. Our results demonstrate that the Spitzer Space Telescope will play an important r...

The most difficult but realistic learning tasks are both noisy and computationally intensive. This paper investigates how, for a given solution representation, coevolutionary learning can achieve the highest ability from the least computation time. Using a population of Backgammon strategies, this paper examines ways to make computational costs reasonable. With the same simple architecture Gera...

Article history: Received 25 January 2013 Received in revised form 8 February 2014 Accepted 20 March 2014 Available online 25 March 2014

The phase error in finite-difference (FD) methods is related to the spatial resolution and thus limits the maximum grid size for a desired accuracy. Greater accuracy is typically achieved by defining finer resolutions or implementing higher order methods. Both these techniques require more memory and longer computation times. In this paper, new modified methods are presented which are optimized...

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