Informatica

The role and goals of computer programming in the education of young people are discussed. The activity of the Lithuanian Young Programmers School by correspondence is described. Motivation of its curriculum and the way of teaching are given. Relations with the competitions of programmers and some other forms of teaching are considered.

The problems and results in constructing the statistical models of multimodal functions are reviewed. The rationality of the search for global minimum is formulated axiomatically and the features of the corresponding algorithm are discussed. The results of some applications of the proposed algorithm are presented.

The maximization problem for an objective function f given on a feasible region X is considered, where X is a compact subset of Rⁿ and f belongs to a set of continuous multiextremal functions on X can be evaluated at any point x in X without error, and its maximum M=max x∈Xf(x) together with a maximizer x^*(a point x^* in X such that M=f(x^*)) are to be approximated. We consider a class of the global random search methods, underlying an apparatus of the mathematical statistics and generalizing the so-called branch and bound methods.

In this report an expert system AKU for diagnostics in acupuncture is described. The injured vital energy channels can be diagnosed using three independent methods: inquiring, Ryodoraku test and Akabane test. The inquiring is constructed as a set of trees whose internal vertices are questions while the leaves are the symptoms of diseases. The production rules describe the correspondence between the symptoms and the state of vital energy “qi” in the channels. AKU is realized by IBM PC computer and used for acupuncture treatment. The program is coded in Turbo Prolog.

Data processing programs combine computations with navigation in a data base. Methods of the structural synthesis of programs are oriented towards construction of computing programs, and the methods of synthesis of relations are oriented towards construction of (logical) navigation paths. An approach to the integration of methods of the structural synthesis of programs and methods of the synthesis of relations is proposed. This approach is based on a computation model (a set of formulas), describing both computations and navigation paths. The sound and complete system of inference rules for the class of formulas, used in such computation models, is given.

The aggregate approach to the formal description, verification and simulation of computer network protocols is considered in the paper. With this approach, the offered design stages can be performed using a single mathematical scheme. The reachability analysis method and the program proof technique are viewed as methods for correctness analysis. The proposed approach for correctness analysis and model construction was used in creating the protocol analysis system PRANAS.

In the papers (Pupeikis, 1988a, b; 1989a, b, c) the problems of efficiency determination, stopping and increase of the effectiveness of asymptotically optimal recursive algorithms are considered respectively by means of estimating time delay in an object and also introducing their robust analogues, stable to outliers in observations. The aim of the given paper is the development of the robust method for a determination of the model order on the basis of determinant ratio. The three methods forming the initial moment matrices are considered. By the first method the elements of the matrix, being the corresponding values of the sample covariance and cross-covariance functions, are calculated by classical formulas. In the case of the second method the same elements are substituted by their robust analogues. The third method is based on an application of auxiliary variables. The results of numerical simulation on a computer (Table 1) indicate the advisability to apply the robust method for determining the model order in the presence of outliers.

This paper briefly reviews some of the recent results on the problems and algorithms for their solution in quadratic 0-1 optimization. First, the complexity of problems is discussed. Next, some exact algorithms and heuristics are mentioned. Finally, results in the analysis of the algorithms for 0-1 quadratic problems are summarized. The papers written in Russian are considered more thoroughly here.