(q ú 0 is fixed); here in order to get close to the optimal set one should approach the parameter t to the optimal value of the problem. As it is well-known, both the parameterizations, under appropriate choice of F , imply polynomial-time interior-point methods for (1) . If G is a polytope, then it is reasonable to choose as F the standard logarithmic barrier for G ; polynomiality of the assoc...

The construction of s-stage explicit twoand three-step peer methods of order p = 2s and p = 3s is considered for the solution of non-stiff second order initial value problems where the right-hand side does not depend on y. By additional conditions superconvergence of order p + 1 can be achieved. Further criteria for good methods are large stability intervals and small error constants. Numerical...

ahead forecasting of hydrological processes Georgia A. Papacharalampous*, Hristos Tyralis and Demetris Koutsoyiannis Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, Iroon Polytechniou 5, 157 80 Zografou, Greece * Corresponding author, [email protected] Abstract: We perform an extensive comparison...

The study of different forms of preconditioners for solving a system of nonlinear equations, by using Newton’s method, is presented. The preconditioners provide numerical stability and rapid convergence with reasonable computation cost, whenever chosen accurately. Different families of iterative methods can be constructed by using a different kind of preconditioners. The multi-step iterative me...

Implicit Explicit (IMEX) schemes are an important and widely used class of time integration methods for both parabolic and hyperbolic partial differential equations. We develop accurate a posteriori error estimates for a user-defined quantity of interest for two classes of multistep IMEX schemes for advection-diffusion-reaction problems. The analysis proceeds by recasting the IMEX schemes into ...

If a reaction proceeds by a large number of elementary steps and involves many different substances, developing its mathematical model “by hand” turns into a quite exhausting procedure fraught with different possible errors, especially provided complicated reaction stoichiometry. This stage can be considerably simplified by using matrix algebra suits. Let us consider a reversible reaction consi...

I n this paper, we specify that the GARCH(1,1) model has strong forecasting volatility and its usage under the truncated standard normal distribution (TSND) is more suitable than when it is under the normal and student-t distributions. On the contrary, no comparison was tried between the forecasting performance of volatility of the daily return series using the multi-step ahead forec...

In this paper, a new method based on genetic-fuzzy algorithm for multi-objective optimization is proposed. This method is successfully applied to several multi-objective optimization problems. Two examples are presented: the first example is the optimization of two nonlinear mathematical functions and the second one is the design of PI controller for control of an induction motor drive supplie...