Journal:Informatica
Volume 8, Issue 1 (1997), pp. 57–82
Abstract
Software system engineering has not yet developed an engineering science for its discipline. On the other hand, a lot of fundamental concepts, shared methods, techniques, patterns for structuring software systems, and languages for documenting design decisions has been accumulated over the years. To analyse and systematise the accumulated ideas is the main challenge for computer scientists today. The main objective of this paper is to analyse software system engineering both as a discipline and as an engineering science. A special attention is paid to conceptual modelling formalisms used in software system engineering.
Journal:Informatica
Volume 8, Issue 1 (1997), pp. 43–56
Abstract
The paper present a proposed approach in the context-free language theory. The main new notion is a graph defining a pushdown automaton (PDA). Each vertex of such graph is a pair (state, stack symbol). Each edge corresponds to a “command” and is labelled by input portion being read by the command and by a “charge” describing the stack word transformation. Some paths of the graph represent PDA's computations. The finite automata are a case of the pushdown graphs. The paper contains some of the author's results based on the approach – the notion of a D-language extending the notion of Dyck's language and the theorem on a representation of a context-free language as a morphical image of the intersection of a D-language with a local set.
Journal:Informatica
Volume 8, Issue 1 (1997), pp. 23–42
Abstract
Today's multimedia and hypermedia systems include such a huge amount of data and links, that they should be stored and maintained by a database system. Then a powerful and efficient database schema is needed. The Dexter hypertext reference model offers a widely accepted, powerful modelling technique for nodes and links. We present its stepwise conversion into a relational multimedia database schema. In the obtained hypermedia engine the most important and most time critical operation is the link navigation. We analyze its complexity in detail and optimize it by schema improvements. Finally we present an efficient implementation of the presented ideas: the System MultiMAP, developed at the TU Munich.
Journal:Informatica
Volume 8, Issue 1 (1997), pp. 3–22
Abstract
The paper introduces to plan generation and the attempts and problems encountered with solutions by deductive methods. It presents the Linear Connection Method as a possibility to overcome the traditional shortcomings of logic for this application, which are discussed in great detail. This is followed by a guide to the research work carried out on the Linear Connection Method and related frameworks.
Journal:Informatica
Volume 7, Issue 4 (1996), pp. 525–541
Abstract
In the present paper, the method of structure analysis for multivariate functions was applied to rational approximation in classification problems. Then the pattern recognition and generalisation ability was investigated experimentally in numerical recognition. A comparison with Hopfield Net was carried out. The overall results of using of new approach may be treated as a success.
Journal:Informatica
Volume 7, Issue 4 (1996), pp. 517–524
Abstract
The problem of dust explosion localization in corn processing enterprises is analysed. Condition of flame spread limiting in pipes is defined. Mathematical models of explosion processes are presented, which enable us to choose a mathematical expression form, with regard to desirable process identification accuracy and the complexity of analytic expressions.
Journal:Informatica
Volume 7, Issue 4 (1996), pp. 495–516
Abstract
An analytical review of recent publications in the area of digital speech signal processing is presented. The aim of the given paper is the analysis of these publications, where Artificial Neural Networks (ANNs) were successfully employed. Numerous methods of ANNs employment are discussed due to identify when and why they are reliable alternative to the conventional adaptive signal processing techniques.
Journal:Informatica
Volume 7, Issue 4 (1996), pp. 485–494
Abstract
A method for processing sequential information of states of technological processes or other complicated dynamic systems and for sequential detection of many abrupt or slow changes in several unknown states is considered. The method is based on a sequential nonlinear mapping of many-dimensional vectors of parameters (collection of which describes the present state of dynamic systems) into two-dimensional vectors in order to reflect the states and their changes on the PC screen. The mapping error function is chosen and expressions for sequential nonlinear mapping are obtained. The mapping preserves the inner structure of distances among the vectors. An example is given. A theoretical minimum amount of parameter vectors mapped simultaneously at the very beginning is obtained.
Journal:Informatica
Volume 7, Issue 4 (1996), pp. 469–484
Abstract
The problem of speaker identification is investigated. Basic segments – pseudostationary intervals of voiced sounds are used for identification. The identification is carried out, comparing average distances between an investigative and comparatives. Coefficients of the linear prediction model (LPC) of a vocal tract, cepstral coefficients and LPC coefficients of an excitation signal are used for identification as features. Three speaker identification methods are presented. Experimental investigation of their performance is discussed.