Informatica

The paper deals with a flow distribution problem with a piecewise-linear cost function. The problem is formulated as a piecewise-linear programming problem which is not separable with respect to separate variable group. The method for solving this problem is based on the extension of the idea of the simplex method to the class of non-separable piecewise-linear problems. It secures finding of a local solution to the problem after a finite number of iterations. The method uses the peculiarities of the problem constraints that make it possible to decompose the matrix of constraints to smaller ones and thus to diminish the volume of calculations.

One of the main problems in pattern classification and neural network training theory is the generalization performance of learning. This paper extends the results on randomized linear zero empirical error (RLZEE) classifier obtained by Raudys, Dičiūnas and Basalykas for the case of centered multivariate spherical normal classes. We derive an exact formula for an expected probability of misclassification (PMC) of RLZEE classifier in a case of arbitrary (centered or non-centered) spherical normal classes. This formula depends on two parameters characterizing the “degree of non-centering” of data. We discuss theoretically and illustrate graphically and numerically the influence of these parameters on the PMC of RLZEE classifier. In particular, we show that in some cases non-centered data has smaller expected PMC than centered data.

The paper deals with the analysis of Research and Technology Development (RTD) in the Central European countries and the relation of RTD with economic and social parameters of countries in this region. A methodology has been developed for quantitative and qualitative ranking and estimates of relationship among multidimensional objects on the base of such analysis. The knowledge has been discovered in four databases: two databases of European Commission (EC) containing data on the RTD activities, databases of USA CIA and The World bank containing economic and social data. Data mining has been performed by means of visual cluster analysis (using the non-linear Sammon's mapping and Kohonen's artificial neural network – the self-organising map), regression analysis and non-linear ranking (using graphs of domination). The results on clustering of the Central European countries and on the relations among RTD parameters with economic and social parameters are obtained. In addition, the data served for testing various features of realisation of the self-organising map. The integration of non-classical methods (the self-organising map and graphs of domination) with classical ones (regress analysis and Sammon' mapping) increases the capacity of visual analysis and allows making more complete conclusions.

This paper considers the problem of likelihood ratio determination for recognition of the stochastic processes with continuous time on the set continuous and discrete time memory observations. The research of memory influence on the detection quality of anomalous noises in the discrete channel observation with applying the general obtained results is realized for the one particular problem.

Amidst the debate on the relative merits of push versus pull technologies, the role of information dynamics over the Internet in shaping truly compelling use of the medium for electronic commerce is being recognized. Focused Broadcasting, a business model of matching classified and want ads using the World Wide Web, is positioned as an example of a balanced approach whose success may be predictable based on market research and analysis. This article reports on a study conducted in New Zealand of Internet user attitudes toward this type of service.

Yamaguchi, Okayama, and Miyahara proposed a simple but efficient authentication system, SPLICE/AS. In this article, we show that their method is vulnerable to the guessing attack. An attacker can obtain the password, private-key, and public-key of the user. To overcome the vulnerability of SPLICE/AS to the guessing attack, we propose an improvement of their system. In our scheme, we not only prevent the guessing attack to obtain secret messages but also enhance the security of the SPLICE/AS authentication system in WIDE.

In the practice of metal treatment by cutting it is frequently necessary to deal with self-excited oscillations of the cutting tool, treated detail and units of the machine tool. In this paper are presented differential equations with the delay of self-excited oscillations. The linear analysis is performed by the method of D-expansion. There is chosen an area of asymptotically stability and area D2. It is prove that, in the area D2 the stable periodical solution appears. The non-linear analysis is performed by the theory of bifurcation. The computational experiment of metal cutting process and results of these experiments are presented.

The paper deals with automatic stressing of the Lithuanian text. In the previous work the author presented an algorithm for automatic stressing of the Lithuanian text on the basis of a dictionary. The aim of the present work is to improve the above mentioned algorithm by including formal stressing rules for nouns and adjectives. By means of these rules such words as diminutives, names and degrees of adjectives that are not present in the dictionary may be stressed. The work analyses when it is more convenient to formulate rules manually and when to generate them automatically. A method for formulating rules manually has been described and a set of such rules has been presented. Besides the algorithm for generating stressing rules with the help of a dictionary of stems of nouns and adjectives has been given.