Journal:Informatica
Volume 2, Issue 3 (1991), pp. 378–402
Abstract
Models for determining the electromagnetic fields are considered. The models consist of system of the Maxwell equations in the complete form and in the quasi-stationary approximation. Using the quasi-stationary approximation in media containing nonconducting subdomains is non correct from the physical point of view and give rise to a number of additional mathematical problems. The solutions of the Maxwell equations in the complete form and in the quasi-stationary approximation are compared. Initial boundary value problems are considered for conducting, nonconducting and mixed media. The conditions ensuring the closeness of solutions are established. The estimates are obtained in terms of input data of the problem. In particular, it has been proved that as the ratio of the characteristic rate to the light velocity tends to zero the strength of electric field in the conducting part and the strength of magnetic field in the entire domain, corresponding to the complete problem, converge to the ones corresponding to the approximate problem.
Journal:Informatica
Volume 2, Issue 3 (1991), pp. 367–377
Abstract
Identification problems of linear dynamic systems in the class of parametric mathematical models are considered. A method of calculating of guaranteed estimates of indefinite parameters is proposed. The method is based on the specific semiinfinite extremal problems solution.
Journal:Informatica
Volume 2, Issue 3 (1991), pp. 352–366
Abstract
Error bounds are developed for a class of quadratic programming problems. The absolute error between an approximate feasible solution, generated via a dual formulation, and the true optimal solution is measured. Furthermore, these error bounds involve considerably less work computationally than existing estimates.
Journal:Informatica
Volume 2, Issue 3 (1991), pp. 331–351
Abstract
The characteristics of the polymodallocally strictly monotone pseudoboolean functions and ones having constancy sets are investigated in this paper; the searchal algorithms for their optimization are proposed; analytical investigation of the proposed algorithms effectiveness is carried out. The paper is a continuation of the authors' researches which were begun before.
Journal:Informatica
Volume 2, Issue 2 (1991), pp. 278–310
Abstract
In general terms some situations are described which require the exploitation of heuristics either to solve a mathematical optimization problem or to analyse results. A possibility to implement heuristic knowledge for selecting a suitable algorithm depending on available problem data and information retrieved from the user, is investigated in detail. We describe some inference strategies and knowledge representations that can be used in this case, and the rule-based implementation within the EMP system for nonlinear programming. Case studies are presented which outline on the one hand the heuristic recommendation of an optimization code and the achieved numerical results on the other hand.
Journal:Informatica
Volume 2, Issue 2 (1991), pp. 255–277
Abstract
The paper considers the analysis technique of the general and individual properties of aggregative specifications. The method is based on constructing a set of axioms describing both the aggregate specifications and the properties of the model under investigation. The resolution method using logical programming language PROLOG is applied in creating the axiom system. An example of aggregative specification analysis for the alternating bit protocol is presented.
Journal:Informatica
Volume 2, Issue 2 (1991), pp. 248–254
Abstract
In well-known statistical models of global optimization only values of objective functions are taken into consideration. However, efficient algorithms of local optimization are also based on the use of gradients of objective functions. Thus, we are interested in a possibility of the use of gradients in statistical models of multimodal functions, aiming to create productive algorithms of global optimization.
Journal:Informatica
Volume 2, Issue 2 (1991), pp. 233–247
Abstract
This paper is concerned with the derivation of open-loop Stackelberg (OLS) solutions of a class of continuous-time two-player nonzero-sum differential games characterized by quadratic cost functionals and linear singular systems. By applying the calculus of variations, necessary conditions are derived under which the open-loop Stackelberg solution of the leader exists. Under the transformation by which the matrix E has diagonal form, we derive a matrix Riccati differential equation from the necessary conditions. An example is given to illustrate the results of the paper.