Informatica

In the mainstream categorical approach to typed (total) functional programming, datatypes are modelled as initial algebras and codatatypes as terminal coalgebras. The basic function definition schemes of iteration and coiteration are modelled by constructions known as catamorphisms and anamorphisms. Primitive recursion has been captured by a construction called paramorphisms. We draw attention to the dual construction of apomorphisms, and show on examples that primitive corecursion is a useful function definition scheme. We also put forward and study two novel constructions, viz., histomorphisms and futumorphisms, that capture the powerful schemes of course-of-value iteration and its dual, respectively, and argue that even these are helpful.

CF-expressions are defined which generalize the regular one. It is established that so called pseudo-coiterating CF-expressions characterize the regular sets. The results are used to develop some more characterizations of the regular sets: the pseudo-coiterating D-graphs and the pseudo-coiterating pushdown automata (PDAs). An algorithm is presented for deciding whether a device of three mentioned types is pseudo-coiterating or not. Apparently, the pseudo-coiterating PDAs form the most large of classes of PDAs the solvability of the question of belonging to which was proved and which are known as characterizations of the regular sets.

In the paper we examine data dependencies in the algorithm of back substitution in the problem of solving triangular systems of linear equations. The aim of the paper is to illustrate the structural blanks (SB) notation in consistency proof of data dependencies in loop programs. Data dependency semantics of programs is introduced and investigated. The introduced notation constitutes the theoretical basis of data dependencies in SB. Two structural modules – a sequential S-module and a parallel one – are examined.

One of the key issues in information systems is to provide a fast and reliable access to data. This is true for conventional databases and information systems as well as for spatial or multimedia ones. Main tools for such aim are indices, among others. Search and reasoning operations using indices and structured data require a specific support on logical and physical level. A years of research have resulted in a great variety of multidimensional data structures and indices (access methods also). This paper overviews recent trends in the area of multidimensional, spatial, temporal indices and data structures, discusses their principles and implementation issues. The special emphasis is given to research, multimedia and spatial information systems.

In this paper we present a method for preparation of technical drawings in the domain of electroplating lines. We treat the method as the combination of two tasks: configuration and document preparation. The proposed method combines the basic concepts of these domains: generic coding introduced in document preparation task and component oriented approach used in the configuration task. We show how both concepts are implemented in our configurator SyntheCAD.

This article provides a brief introduction to an approach toward data conversion development. The article discusses activities in the area of conversion software development, as well as a model for the life cycle of this development process. Also analyzed is a possible method of tool support for the development process.

An algorithm for updating the evidence in the Dempster-Shafer theory is presented. The algorithm is based on an idea of indices. These indices are used to code the process of reasoning under uncertainty (the combination of evidence)using the Dempster-Shafer theory. The algorithm allows to carry out the reasoning with updating the evidence in much more efficient way than using the original Dempster-Shafer theory. Updating the evidence is necessary among others in systems that are based on changing data – adaptive and distributed reasoning systems.