Fundamenta Informaticae - Volume 52, issue 4

Authors: Dey, Sabyasachi | Bhattacharya, Bhargab B. | Kundu, Malay K. | Acharya, Tinku Acharya

Article Type: Research Article

Abstract: In this paper, a new methodology for computing orientation of a gray-tone image by the method of moments is described. Orientation is an essential feature needed in many image processing and pattern recognition tasks. Computation of moments is accomplished by a new projection method that leads to a fast algorithm of determining orientation. Using a simple architecture, the proposed algorithm can be implemented as a special purpose VLSI chip. The hardware cost of the proposed design …is significantly lower compared to that of the existing architecture. Show more

Keywords: digital imaging, orientation, projection method, VLSI

Citation: Fundamenta Informaticae, vol. 52, no. 4, pp. 285-295, 2002

Authors: Eshuis, Rik | Fokkinga, Maarten M.

Article Type: Research Article

Abstract: Refinement in bisimulation semantics is defined differently from refinement in failure semantics: in bisimulation semantics refinement is based on simulations between labelled transition systems, whereas in failure semantics refinement is based on inclusions between failure systems. There exist however pairs of refinements, for bisimulation and failure semantics respectively, that have almost the same properties. Furthermore, each refinement in bisimulation semantics implies its counterpart in failure semantics, and conversely each refinement in failure …semantics implies its counterpart in bisimulation semantics defined on the canonical form of the compared processes. Show more

Keywords: refinement, labelled transition systems, bisimulation semantics, failure semantics, decorated traces

Citation: Fundamenta Informaticae, vol. 52, no. 4, pp. 297-321, 2002

Authors: Fan, Tuan-Fang | Liau, Churn-Jung | Yao, Yiyu

Article Type: Research Article

Abstract: Some modal decision logic languages are proposed for knowledge representation in data mining through the notions of models and satisfiability. The models are collections of data tables consisting of a finite set of objects described by a finite set of attributes. Some relationships may exist between data tables in a collection and the modalities of our languages are interpreted with respect to these relations in Kripkean style semantics. The notion of fuzzy decision logic is also …reviewed and combined with the modal decision logic. The combined logic is shown to be useful in the representation of fuzzy sequential patterns. Show more

Keywords: data table, decision logic, modal decision logic, fuzzy decision logic, rough set theory

Citation: Fundamenta Informaticae, vol. 52, no. 4, pp. 323-344, 2002

Authors: Novotný, Miroslav

Article Type: Research Article

Abstract: A construction is described assigning a pure grammar G_{mrn} to any language and to any integers 0≤m≤r≤n. This construction has the following property: If the sequence (G_{mrn})_{n≥r} has a limit G_{mr} for any r≥m and if the sequence (G_{mr})_{r≥m} has a limit, then the given language is generated by a pure grammar. By a limit of a sequence (a_{k})_{k≥k_{0}} we understand a member a_{k_{1}} of the sequence such that k_{1}≥k_{0} and a_{k}=a_{k_{1}} for any k≥k_{1}.

Keywords: generalized pure grammar, pure grammar, relation of domination, reducing operator

Citation: Fundamenta Informaticae, vol. 52, no. 4, pp. 345-360, 2002

Authors: Okhotin, Alexander | Salomaa, Kai | Domaratzki, Michael

Article Type: Research Article

Abstract: We study caterpillar tree automata [3] that are restricted to enter any subtree at most one time (or k times). We show that, somewhat surprisingly, the deterministic one-visit automata can already, for instance, evaluate trees where the nodes represent some non-associative operations. We show that there exist regular tree languages that cannot be accepted by a one-visit automaton, thus proving a weakened form of a conjecture of Brüggemann-Klein and Wood [3]. We establish that the k-visit …property is decidable. Show more

Keywords: tree automata, regular tree languages, markup languages, k-visit property

Citation: Fundamenta Informaticae, vol. 52, no. 4, pp. 361-375, 2002

Authors: Terlikowski, Tomasz

Article Type: Research Article

Abstract: In this paper, we introduce logical notions of positive implication and positive correspondence aimed at a formalization of notions of safety of control variants in control theory.

Keywords: first-order logic, set theory, positive implication, positive correspondence, safe set of control variants

Citation: Fundamenta Informaticae, vol. 52, no. 4, pp. 377-394, 2002