Journal:Informatica
Volume 11, Issue 1 (2000), pp. 41–48
Abstract
The survey of the current status in ontological engineering is presented: notion, peculiarities, applications, design and evaluation of ontologies. The possibilities of using The Brain™, a personal desktop productivity tool, for visualisation of ontologies are outlined and compared with that of Hyperbolic ontology viewer of Ontobroker.
Journal:Informatica
Volume 11, Issue 1 (2000), pp. 19–40
Abstract
The paper deals with one of the components of text-to-speech synthesis of the Lithuanian language, namely – automatic text stressing. The present work substantiates the necessity to divide words into fixed and variable parts used to build different grammatical forms, as well as to store only those parts rather than the whole worlds in the dictionary. According to the inflexion method, all words of the Lithuanian language are divided into three groups (noun-adjectives, verbs and non-inflectional words) and each group is analysed separately. The type of information, as well as the form in which it is to be stored, has been established for each group and the algorithm by means of which the grammatical form of a word can be recognised and stressed, has been presented.
Journal:Informatica
Volume 11, Issue 1 (2000), pp. 15–18
Abstract
Recently, Harn proposed an efficient scheme that can batch verification multiple RSA digital signatures. His scheme can reduce signature verification time. However, there is a weakness in his scheme. In this study, we present two methods to against his scheme.
Journal:Informatica
Volume 11, Issue 1 (2000), pp. 3–14
Abstract
The paper presents a simple programming language and rewriting system called GENS. It is based on an extension of the λ-calculus called λE-calculus. GENS is a multiparadigm language: it has been used for definition of semantics and for implementation of functional, logical, procedural, and object-oriented languages. It also allows combining different programming paradigm styles in a single programming language.
The purpose of this paper is to define and to introduce the λE-calculus – theoretical foundation of GENS. It will also be shown how the most important language constructs of different programming paradigms can be defined in GENS.
Journal:Informatica
Volume 10, Issue 4 (1999), pp. 457–466
Abstract
The Steiner problem asks for the shortest network that spans a given set of fixed points in the Euclidean plane. The problem is NP hard.
The result of simulation of an idealized “wet” film connecting fixed points is a length-minimizing curve. Increasing the exterior pressure step by step we are able to achieve the film configuration near to the Steiner minimal tree. “Dead-point” situations may occur for some symmetric allocation of fixed points.
The limited simulation experiments show that the average computation time depends almost linearly on the number of fixed points for the situations without “dead-points”.
Journal:Informatica
Volume 10, Issue 4 (1999), pp. 441–456
Abstract
A model for an age-sex-structured nonlimited population dynamics with the harmonic mean type mating law and females' pregnancy is presented. The existence and uniqueness theorem for the general case of vital rates is proved, the extinction and growth of the population are considered, and a class of the product (separable) solutions is obtained.
Journal:Informatica
Volume 10, Issue 4 (1999), pp. 427–440
Abstract
A probabilistic Büchi automaton PBA is defined. The probabilistic language (L, p) as defined by the PBA is defined. A decomposition theorem similar to the classical Krohn-Rhodes theorem, but for PBA is proved.
Journal:Informatica
Volume 10, Issue 4 (1999), pp. 403–426
Abstract
The aim of the article is to show a stochastic approach for both modelling and optimizing the statistical agent belief in a probability model.
Two networks are defined: a decision network $\mathfrak{D}$ of the agent belief state and a utility network $\mathfrak{U}$, presenting the utility structure of the agent belief problem.
The agent belief is presented via the following three items ($\mathfrak{B},\mathfrak{D},\mathfrak{U}$), where $\mathfrak{B}$ is a Bayesian network, presenting the probability structure of the agent belief problem.
Two propagation algorithms in $\mathfrak{D}$ and in $\mathfrak{U}$ are also presented.
Journal:Informatica
Volume 10, Issue 4 (1999), pp. 389–402
Abstract
The paper presents a fingerprint registration approach based on the decomposition of registration process into elementary stages. In each stage a single transformation parameter is eliminated. The algorithm uses composite features, i.e., lines connecting two minutiae instead of fingerprint minutiae. These features have rotation and translation-invariant attributes allowing feature filtering with significantly enhanced signal-to-noise ratio in feature consensus scheme. Experimental results of goal-directed performance evaluation with live-captured fingerprint image database are presented.
Journal:Informatica
Volume 10, Issue 4 (1999), pp. 377–388
Abstract
The problem of text-independent speaker recognition based on the use of vocal tract and residue signal LPC parameters is investigated. Pseudostationary segments of voiced sounds are used for feature selection. Parameters of the linear prediction model (LPC) of vocal tract and residue signal or LPC derived cepstral parameters are used as features for speaker recognition. Speaker identification is performed by applying nearest neighbour rule to average distance between speakers. Comparison of distributions of intraindividual and interindividual distortions is used for speaker verification. Speaker recognition performance is investigated. Results of experiments demonstrate speaker recognition performance.