In the framework of the project ‘Windbank’, wind field patterns in an area of 30km×30km in the Swiss Plateau between the Alps and the Jura were measured with 22 temporary meteorological stations and two SODARs during 4 months in 1997. Hourly averages from this high resolution network were...

Railway interlocking systems are designed to prevent conflicting actions (related to the position of switches and signals) during everyday railway exploitation. A decision model (independent from the topology of the station) based on the use of polynomial ideals and Gröbner bases is presented....

In this work, we apply the Lindstedt–Poincaré method in order to seek the periodic solutions of the Barbanis–Contopoulos nonintegrable Hamiltonian system. We first prove that this system admits six nontrivial periodic families in the neighbourhood of the origin. Then we compute the series...

In this paper we describe a recent computer implementation (the PASCAL program TERA) of a well known Computer Algebra algorithm. The particularity of this implementation consists in the fact that it is based on a special abstract data type, namely that of a directed acyclic graph (DAG) which is...

In this work we consider the Helmholtz equation in a hyperparallelepiped Ω⊂Rd, d=1,2,3,…, under Dirichlet boundary conditions and for its solution we apply the averaging technique of the nonoverlapping Domain Decomposition, where Ω is decomposed in two, in general not equal, subdomains....

The zonal polynomials are symmetric polynomial functions each of which is an eigenfunction of a kind of Laplace–Beltrami operator. We give a simplification of the Laplace–Beltrami operator. We realize a symbolic algorithm for obtaining the coefficients of zonal polynomials.

For many technical systems the use of a refined network approach yields mathematical models given by initial-boundary value problems of partial differential algebraic equations (PDAEs). The boundary conditions of these systems are governed by time-dependent differential–algebraic equations...

The paper compares the direct collocation with nonlinear programming method and the quadrature rule scheme in the category of direct optimization methods. It is pointed out that the original quadrature rule scheme produces control discontinuities as the result of discrete computation of the...

A difference equation with infinitely many delays was considered, which gives a ‘best’ approximation of logistic integrodifferential equation. Some biological and evolutionary consequences are briefly discussed.

Today’s high-performance computing environments, and the applications that must exploit them, have become much more complex than ever. We now build ensembles of large, shared-memory parallel computers, linked together with high-speed networks, in an attempt to achieve previously unheard-of...