Informatica

A multiextremal problem on the synthesis of external circuit of a tunable subnanosecond pulse TRAPATT-generator was investigated using algorithms of local optimization and cluster analysis.

The results of investigation of computer programs written by school students during the 6th International Olympiad in Informatics are presented. Pascal program texts are analyzed on the lexical level. A certain relationship is indicated between program correctness and usage of some programming constructs as well as readability of the program text. The results are discussed from the standpoint of programming teaching.

Two-dimensional signals of physical phenomena may be inadvertently altered before recording through the system whose bandwidth is smaller than that of the signal. It is often desired to restore later such data by removing the effects of the linear system. This restoration may be accomplished by synthesizing two-dimensional (2-D) inverse filters on computers. Approximations are necessary to insure the stability of the inverse filter.

We compare two alternative ways to use the Bayesian approach in heuristic optimization. The “no-learning” way means that we optimize the randomization parameters for each problem separately. The “learning” way means that we optimize the randomization parameters for some “learning” set of problems. We use those parameters later on for a family of related problems.

In the papers (Kaminskas, 1972; Kaminskas and Nemura, 1975; Yin, 1989) the stopping rules of recursive least squares (RLS) are worked out using the ellipsoidal confidence region for the respective parameter vector of a linear dynamic system. The aim of the given paper is the development of the technique for calculating threshold intervals of respective criterions, used in a stopping rule, which are presented in Kaminskas (1972). In this connection adaptive threshold intervals based on the Cramer-Rao lower bound are proposed here. The results of numerical simulation by IBM PC/AT are given.

The exact solution of the reliability of structures under stochastic loading is generally difficult, and various approximate methods have been developed. The most popular are the linearization method, the Monte-Carlo method and its numerous variants. In this paper new modification of the Monte-Carlo method based on asymptotical expansion is examined. Results of mathematical simulation are given.

This paper presents a robust control algorithm for plants involving both internal (i.e., in the state) and external (i.e., in the output or input) known point delays. Several stabilizing controller structures are given and analyzed for the case of perfectly modelled plants with known parameters. The plant is assumed to be of known order and relative order. The parametrized parts of two of the controller structures involve delays while those of the two remaining controllers are delay-free. However, auxiliary compensating signals which weight the plant input and output integrals are incorporated in all the controller structures for stabilization and model matching purposes.

In this paper, taking into account the size, age structure and pregnancy of females, the model, which describes the evolution of non-migrating limited panmiction population, composed of two-sexes, is considered. In case, where reproductive period is equal or less than gestation period, death rates and fecundation function depend on population size, the unique solvability of the model is established.