Informatica

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.

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.

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.

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.

Growing popularity of the mobile code requires to consider various aspects related to its security. In the aviation industry there is a case when additional information needs to be delivered to the pilot by uploading it from the ground station. It creates a need for a platform-independent solution and it raises a problem of the mobile code security as well. Organization of the security in the Base System (similar to extranets) as well as the security issues of the mobile code (or safelets for use in the aircrafts) delivered to the Remote Platform are discussed in the paper. Safelet implementation technologies and issues of code effectiveness and safety itself are discussed with Java and Juice/Oberon technologies been compared.

An original algorithm for transformation of finite automata to regular expressions is presented. This algorithm is based on effective graph algorithms and gives a transparent new proof of equivalence of regular expressions and finite automata.

We present the capabilities of the scripting language Open PROMOL and its processor. The intention of the language is to pre-program specifications for modifying programs written in a target language. We use its processor either as a tool for developing the stand-alone reusable components or as a “component-from-the-shelf” in generative tools for generating domain specific programs. The processor itself uses the module (lexical analyser and parser) produced by Lex & Yacc as a reusable component. We describe the generation, computation, control, parameterization and gluing capabilities of the language. We compare our approach with the similar approaches known in the literature.

A system of two nonlinear difference-differential equations which is a mathematical model of self-regulation of glucose level in blood with time delay into consideration of insulin “age structure” is presented. The analysis carried out by qualitative and numerical methods allows us to conclude, that the mathematical model explains the functioning of the physiological system “insulin-blood glucose” in normal and pathological cases.

This paper contains measures to describe the matrix impulse response sensitivity of state space multivariable systems with respect to parameter perturbations. The parameter sensitivity is defined as an integral measure of the matrix impulse response with respect to the coefficients. A state space approach is used to find a realization of impulse response that minimizes a sensitivity measure.