Journal:Informatica
Volume 13, Issue 3 (2002), pp. 275–286
Abstract
In the paper, we analyze the software that realizes the self-organizing maps: SOM-PAK, SOM-TOOLBOX, Viscovery SOMine, Nenet, and two academic systems. Most of the software may be found in the Internet. These are freeware, shareware or demo. The self-organizing maps assist in data clustering and analyzing data similarities. The software differs one from another in the realization and visualization capabilities. The data on coastal dunes and their vegetation in Finland are used for the experimental comparison of the graphical result presentation of the software. Similarities of the systems and their differences, advantages and imperfections are exposed.
Journal:Informatica
Volume 13, Issue 3 (2002), pp. 255–274
Abstract
We present an analysis of the separation of concerns in multi-language design and multi-language specifications. The basis for our analysis is the paradigm of the multi-dimensional separation of concerns, which claims that multiple dimensions of concerns in a design should be implemented independently. Multi-language specifications are specifications where different concerns of a design are implemented using separate languages as follows. (1) Target language(s) implement domain functionality. (2) External (or scripting, meta-) language(s) implement generalisation of the repetitive design features, introduce variations, and integrate components into a design. We present case studies and experimental results for the application of the multi-language specifications in hardware design.
Journal:Informatica
Volume 13, Issue 2 (2002), pp. 239–250
Abstract
The new strategy for non-uniform initial FE mesh generation is presented in this paper. The main focus is set to a priori procedures that define the sizing function independent on the mesh generation algorithm. The sizing function used by the mesh generation algorithm is established by control sphere and control space concepts and fully controls mesh gradation in the complex 2D problem domains.
Journal:Informatica
Volume 13, Issue 2 (2002), pp. 227–238
Abstract
The problem of supervised classification of the realisation of the stationary univariate Gaussian random field into one of two populations with different means and factorised covariance matrices is considered. Unknown means and the common covariance matrix of the feature vector components are estimated from spatially correlated training samples assuming spatial correlation to be known. For the estimation of unknown parameters two methods, namely, maximum likelihood and ordinary least squares are used. The performance of the plug-in discriminant functions is evaluated by the asymptotic expansion of the misclassification error. A set of numerical calculations is done for the spherical spatial correlation function.
Journal:Informatica
Volume 13, Issue 2 (2002), pp. 209–226
Abstract
Five methods for count data clusterization based on Poisson mixture models are described. Two of them are parametric, the others are semi-parametric. The methods emlploy the plug-in Bayes classification rule. Their performance is investigated by making use of computer simulation and compared mainly by the clusterization error rate. We also apply the clusterization procedures to real count data and discuss the results.
Journal:Informatica
Volume 13, Issue 2 (2002), pp. 177–208
Abstract
The objective of expert systems is the use of Artificial Intelligence tools so as to solve problems within specific prefixed applications. Even when such systems are widely applied in diverse applications, as manufacturing or control systems, until now, there is an important gap in the development of a theory being applicable to a description of the involved problems in a unified way. This paper is an attempt in supplying a simple formal description of expert systems together with an application to a robot manipulator case.
Journal:Informatica
Volume 13, Issue 2 (2002), pp. 163–176
Abstract
This paper is concerned with design, implementation and verification of persistent purely functional data structures which are motivated by the representation of natural numbers using positional number systems. A new implementation of random-access list based on redundant segmented binary numbers is described. It uses 4 digits and an invariant which guarantees constant worst-case bounds for cons, head, and tail list operations as well as logarithmic time for lookup and update. The relationship of random-access list with positional number system is formalized and benefits of this analogy are demonstrated.
Journal:Informatica
Volume 13, Issue 2 (2002), pp. 149–162
Abstract
A tool for modeling the propagation of optical beams is proposed and investigated. Truncated Laguerre–Gauss polynomial series are used for approximation of the field at any point in free space. Aposteriori error estimates in various norms are calculated using errors for input functions. The accumulation of truncation errors during space transition is investigated theoretically. The convergence rate of truncated LG series is obtained numerically for super-Gaussian beams. An optimization of algorithm realization costs is done by choosing parameters in such a way that the error reaches minimum value. Results of numerical experiments are presented.
Journal:Informatica
Volume 13, Issue 2 (2002), pp. 133–148
Abstract
We study the stochastic model for bioremediation in a bioreactor with ideal mixing. The dynamics of the examined system is described by stochastic differential equations. We consider an optimal control problem with quadratic costs functional for the linearized model of a well-stirred bioreactor. The optimal control is based on the optimal robust state estimates. The approximate optimal solution is obtained as a linear feedback.
Journal:Informatica
Volume 13, Issue 1 (2002), pp. 111–128
Abstract
In this paper, we analyze the abstractions used for developing component-based domain generators. These include programming paradigms, programming languages, component models, and generator architecture models. On the basis of the analysis, we present a unified relationship model between the domain content, technological factors (structuring, composition, and generalization), and domain architecture. We argue that this model is manifested in the known software generator models, too.