Journal:Informatica
Volume 7, Issue 1 (1996), pp. 83–96
Abstract
The equations describing the evolution of migrating populations composed of two-sexes are derived taking into account the size, age structure, panmiction mating of sexes, pregnancy of females, possible abortions as well as the females organism restoration periods after abortions and delivery. In partial case, which neglects females organism restoration period, the unique solvability of the model is proved and the condition for population to vanish is obtained.
Journal:Informatica
Volume 7, Issue 1 (1996), pp. 39–82
Abstract
This paper presents a direct adaptive, control algorithm, based on a σ-modification rule, which is robust respect to additive and multiplicative plant unmodelled dynamics for plants involving both internal (i.e., in the state) and external (i.e., in the output or input) known point delays. Several adaptive controller structures are given and analyzed for the case of plants with unknown parameters while being assumed that the nominal plant is of known order and relative order. The parametrized parts of two of the controller structures involve delays while those of the two remaining controllers are delay-free. However, auxiliary compensating signals which weight the plant input and output integrals are incorporated in all the controller structures for stabilization purposes. It is proved that, if the unmodelled dynamics is sufficiently small at low frequencies, then the adaptive algorithm guarantees boundedness of all the signals in the closed-loop system.
Journal:Informatica
Volume 7, Issue 1 (1996), pp. 27–38
Abstract
In the papers (Kaminskas, 1973; Kaminskas and Nemura, 1975) the stopping rule of recursive least squares (RLS) is worked out using the length of the confidence interval for the respective current meaning of the true output signal of a linear dynamic system. The aim of the given paper is the development of techniques for calculating threshold intervals of respective criteria, used in such a stopping rule. In this connection adaptive threshold intervals based on the Cramer-Rao lower bound according to Pupeikis (1995) are proposed here, too. The results of numerical simulation by IBM PC/AT are given.
Journal:Informatica
Volume 7, Issue 1 (1996), pp. 15–26
Abstract
In this paper, we propose to present the direct form recursive digital filter as a state space filter. Then, we apply a look-ahead technique and derive a pipelined equation for block output computation. In addition, we study the stability and multiplication complexity of the proposed pipelined-block implementation and compare with complexities of other methods. An algorithm is derived for the iterative computation of pipelined-block matrices.
Journal:Informatica
Volume 7, Issue 1 (1996), pp. 3–14
Abstract
A fuzzy method for incorporating the contextual constraints into a text recognition system is presented here. The method takes as input all the internal result that an Isolated Character Classifier (ICC) computes for an input letter, instead of an unique output character. The internal result is handled here as a fuzzy set which is then processed by a Deformed System. Such a Deformed System represents a dictionary of legal words, and it is actually a Finite Automaton which has been modified for accepting as input no single symbols but fuzzy sets. Several tests have been carried out in a Text Recognition System and the obtained results show the suitability of the method.
Journal:Informatica
Volume 6, Issue 4 (1995): Special Issue on Information Systems and Software Systems Engineering, pp. 497–522
Abstract
In this paper the universal structural type of entities is presented by recursive applications of two operators, i.e., operator which constructs positioned subsets of entity name universum and operator which constructs a functional set on the entity name universum. The object subtype is determined using an especial commutational diagram with the compositions of inner functions. The main integration rule of conceptual object–relationship–property scheme is determined by means of external containment function. A compositions of inner and external functions serve as a tool for normalization of entities systems. The advantages of proposed approach to the modelling of entities system are pointed out.
Journal:Informatica
Volume 6, Issue 4 (1995): Special Issue on Information Systems and Software Systems Engineering, pp. 483–496
Abstract
The development of software systems is intensive person-oriented process. Therefore it is essential to use previous experience and knowledge. The extension of reuse through analogy is analysed in this paper. The proposed grouping of analogical methods, rules, etc., relies on their adaptability to application software development. The emphasis here is on analogue as a criterion to safeguard the desirable properties of application software. Knowledge kinds and mechanisms to enable reuse through analogy are discussed.
Journal:Informatica
Volume 6, Issue 4 (1995): Special Issue on Information Systems and Software Systems Engineering, pp. 457–482
Abstract
Enterprise goals justify and explain the presence of information system constraints, activities and actors. One of the main problem in the area of enterprise modelling is to bridge the gap between the description of goal as early requirement statement and the precise specification of related to this goal limited area of activity of which a stakeholder is concerned. Various kinds of entities, relationships and rules in the specification of several information system views exist for some reason, because they express the needs and rationales of requirements at the pragmatic level. On the other hand, goals justify and explain the presence of requirement components. Description of goals in terms of static and dynamic constraints is of interest, because it allows interpretation of goal descriptions as a driving force in the process of information system modelling at the organisational level.
The main focus of EUROMETHOD is on the contractual level starting with the call for tender, proceeding through the signing of a contract, eventually entering into the actual production of a set of deliverables. EUROMETHOD is focusing on the dynamic contractual relationships between customer and supplier. The basis of a contract consist of the specification of a problematic situation, and some general intentions and constraints for the description of a final state. Although the desired constraints and intentions of the information system could be formulated in the form of objectives, this part by EUROMETHOD is not guided. The aim of this paper is to introduce a unifying framework for modelling of enterprise goals in terms of semantic descriptions of information system views. Such a framework provide basis for better understanding of contractual customer-supplier relationships within several worlds of enterprise modelling.
Journal:Informatica
Volume 6, Issue 4 (1995): Special Issue on Information Systems and Software Systems Engineering, pp. 445–456
Abstract
The algebra–grammar model of user interface (UI) and the method of UI creation and updating by combining the visual formalisms are proposed. The UI building tools for applications of “MicroPoisk” DBMS are described. Special attention is paid to the requirements of the UI standards.
Journal:Informatica
Volume 6, Issue 4 (1995): Special Issue on Information Systems and Software Systems Engineering, pp. 397–444
Abstract
We present two methods for expressing computations based on recurrence relations and discuss their relative merits. One method, the structural blanks approach, is built on top of traditional programming languages like Fortran or Pascal. It aims at program reuse and bases a certain architecture of software packages. The other method, the constructive recursive approach, is based on recursive relations over graphs.