In this article, two decision models for railway interlocking systems are presented. The first – for the case that the turnouts have spring switches- and the second – for the case that the turnouts should not be trailed through a switch set against-. In both cases, the algorithm is...

The rise of the power level of the converters requires more and more accurate methods to evaluate the current harmonics. Two structures of variable speed drives are investigated and a comparison of their usual models is proposed. A probabilistic approach is employed to determine the influence of...

More and more applications require contactless energy transmission: machine tools (rotating table, x–y tables), robotics, electric vehicle loading systems, high speed transportation, a.s.o. The electromagnetic inductive technique is a good solution in a wide range of power. The aim of this...

This paper presents a general sampled data modeling of power systems supplied by static converter with digital and analog controller. The case of a switched reluctance motor is presented. A description of the system in terms of differential and switching equations leads directly to the...

Let r be the sample correlation coefficient. In this paper, we clarify the role of computer algebra to obtain an asymptotic expansion for probability integrals of r. A key technique is to use a change of bases of the module of symmetric polynomials. We describe an algorithm for accomplishing it....

Computer algebra systems (CAS) are not only useful for relieving us of boring and/or difficult algebraic calculations (and numerical ones as well) but more and more they are used within mathematics education to gain more insight, to focus on the basic concepts, and to open many fields of...

In this paper, we present algorithms for representing and computing with multivariate polynomials and multivariate polynomial matrices, which are given by straight-line programs that are implemented as arithmetic circuits. This data structure allows the representation and evaluation of the...

A new method to produce convex and smooth grids over general plane regions is introduced. This method belongs to the discrete variational grid generation approach. Theoretical results presented guarantee that a convex grid over a region is obtained when this method is applied; the basic assumption...

This paper presents a technique to simplify regular expressions. Several ideas from Computer Algebra and symbolic computing are applied to the regular expression symbolic domain. An implementation of the described technique has been developed.

Periodically regenerateable cake-forming filters have assumed a commercially dominant role in air purification because of their excellent dust collection capabilities. However intensive experimental investigations are usually necessary to optimally design such filters due to the absence of...