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Authors: Pancerz, Krzysztof

Article Type: Research Article

Abstract: The main goal of the paper is to show the idea of incorporating paradigmatic and syntagmatic relations into processing data stored in information tables using rough set methods. Input data, in a tabular form, are used in many machine learning and computational intelligence methods and algorithms, among others, those based on rough set theory. Additional knowledge about semantic relations (both paradigmatic and syntagmatic) can be considered as a useful context affecting data classification or clustering.

Keywords: information systems, rough sets, ontological graphs, semantic relations, paradigmatic relations, syntagmatic relations

DOI: 10.3233/FI-2016-1432

Citation: Fundamenta Informaticae, vol. 148, no. 1-2, pp. 229-242, 2016

Authors: Suraj, Zbigniew | Pancerz, Krzysztof

Article Type: Research Article

Abstract: This paper deals with reconstruction of net models of concurrent systems described by information systems changing in time. Constructed net models have the form of coloured Petri nets. Resulting nets are constructed on the basis of decomposed information systems. In many practical cases, a description of modelled systems changes in time. New knowledge about structures and behaviours of systems appears. When new descriptions appear, the net models should be changed taking into consideration the new knowledge. An approach to reconstruction of net models is presented here. One of many possible cases is considered, i.e., when the new global state of …the modelled system appears. The ability to compute reducts and components of a new information system, being a new description of a modelled system, in an efficient way is important for reconstruction. Therefore, some propositions and corollaries useful to compute reducts of a new information system on the basis of reducts of an old information system are given. These propositions and corollaries are the basis to formulate algorithms for computing new reducts and components. Moreover, a way to determine the cost of the reconstruction of a net model is given. The cost of the reconstruction is treated as the cost of adding new functional modules, communication lines or their modifications. The discussed approach to model reconstruction extends and refines that proposed by Z. Suraj in 1998. An example is given in this paper to illustrate the presented idea. Show more

Keywords: information systems, coloured Petri nets, data table decomposition, model reconstruction

Citation: Fundamenta Informaticae, vol. 71, no. 1, pp. 121-137, 2006

Authors: Pancerz, Krzysztof | Suraj, Zbigniew

Article Type: Research Article

Abstract: The aim of this paper is to present the methods and algorithms of information systems decomposition. In the paper, decomposition with respect to reducts and the so-called global decomposition are considered. Moreover, coverings of information systems by components are discussed. An essential difference between two kinds of decomposition can be observed. In general, global decomposition can deliver more components of a given information system. This fact can be treated as some kind of additional knowledge about the system. The proposed approach is based on rough set theory. To demonstrate the usefulness of this approach, we present an illustrative example coming …from the economy domain. The discussed decomposition methods can be applied e.g. for design and analysis of concurrent systems specified by information systems, for automatic feature extraction, as well as for control design of systems represented by experimental data tables. Show more

Keywords: decomposition, information analysis, information system, knowledge representation, machine learning, reduct, rough sets

DOI: 10.3233/FI-2013-908

Citation: Fundamenta Informaticae, vol. 127, no. 1-4, pp. 257-272, 2013

Authors: Pałasiński, Marek | Pancerz, Krzysztof

Article Type: Research Article

Abstract: The aim of this paper is to give the basic view on computing consistent extensions and restrictions of information systems noting some order properties of information system families. Information systems are understood in the Pawlak’s sense as the systems of knowledge representation. The extension appears if we add to the original information system some new objects corresponding to the known attribute values. Analogously, the restriction appears if we remove from the original information system some objects. Presented observations enable us to find proper descriptions (preserving some features) of concurrent systems whose behavior is represented by means of information systems.

DOI: 10.3233/FI-2010-277

Citation: Fundamenta Informaticae, vol. 101, no. 1-2, pp. 91-103, 2010

Authors: Grochowalski, Piotr | Pancerz, Krzysztof

Article Type: Research Article

Abstract: The paper gives the outline of an ontology for the rough set theory and its applications. This ontology will be applied in intelligent searching the Rough Set Database System. A specialized editor from the Protege system is used to define the ontology.

Keywords: ontology, rough sets, data mining, knowledge discovery, database systems

DOI: 10.3233/FI-2009-0093

Citation: Fundamenta Informaticae, vol. 93, no. 1-3, pp. 143-154, 2009

Authors: Suraj, Zbigniew | Pancerz, Krzysztof

Article Type: Research Article

Abstract: This paper provides new algorithms for computing consistent and partially consistent extensions of information systems. A maximal consistent extension of a given information system includes only objects corresponding to known attribute values which are consistent with all rules extracted from the original information system. A partially consistent extension of a given information system includes objects corresponding to known attribute values which are consistent to a certain degree with the knowledge represented by rules extracted from the original information system. This degree can be between 0 and 1, 0 for the full inconsistency and 1 for the full consistency. The algorithms …presented here do not involve computing any rules true in a given information system. This property differentiates them from methods presented in the earlier papers which concerned extensions of information systems. Show more

Keywords: rough sets, information systems, consistent extensions, partially consistent extensions

Citation: Fundamenta Informaticae, vol. 79, no. 3-4, pp. 553-566, 2007

Authors: Pancerz, Krzysztof | Suraj, Zbigniew

Article Type: Research Article

Abstract: The synthesis problem of concurrent systems has earlier been discussed in the literature using different types of formalisms. This paper presents a new method for discovery of asynchronous concurrent models from experimental tables by using a rough set approach. The proposed method can be applied to the automatic data model discovery. The algorithm for constructing asynchronous concurrent models is described in detail. As a model for concurrency the Coloured Petri Nets are used. Constructed asynchronous models can be helpful to solving some problems arising in design of asynchronous digital systems or addressing of nodes in parallel systems. An example illustrates …an application of the proposed approach in such problems. Show more

Keywords: information systems, rough sets, concurrency, asynchronous models, Coloured Petri Nets

Citation: Fundamenta Informaticae, vol. 61, no. 2, pp. 97-116, 2004

Authors: Pancerz, Krzysztof | Suraj, Zbigniew

Article Type: Research Article

Abstract: The synthesis problem of concurrent data models from experimental tables based on rough set approach has earlier been discussed [14], [15] Classical Petri nets have been used as a model for concurrency. In this paper we propose the nets with inhibitor expressions and Coloured Petri Nets as models for concurrency. The nets with inhibitor expressions are defined on the base of so called inhibitor rules extracted from modelled systems. The approach presented in this paper enables to implement the algorithms for easier construction of Petri net models. The proposed approach can be applied to discover data models in semi-automatic way. …The obtained models enable us to determine all global states of a modelled system represented by an information system, consistent with all rules extracted from the given information system. Show more

Keywords: information system, rough sets, concurrency, nets with inhibitor expressions, Coloured Petri Nets

Citation: Fundamenta Informaticae, vol. 55, no. 2, pp. 149-165, 2003

Authors: Schumann, Andrew | Pancerz, Krzysztof

Article Type: Research Article

Abstract: Our research is focused on creation of a new object-oriented programming language for Physarum polycephalum computing. Physarum polycephalum is a one-cell organism that can be used for developing a biological architecture of different abstract devices, among others, the digital ones. In the paper, we use an abstract graphical language in the form of Petri nets to describe the Physarum polycephalum behavior. Petri nets are a good formalism to assist designers and support hardware design tools, especially in developing concurrent systems. At the beginning stage considered in this paper, we show how to build Petri net models, and next implement them …as Physarum polycephalum machines, of basic logic gates AND, OR, NOT, and simple combinational circuits on the example of the 1-to-2 demultiplexer. Show more

DOI: 10.3233/FI-2014-1076

Citation: Fundamenta Informaticae, vol. 133, no. 2-3, pp. 271-285, 2014

Authors: Pancerz, Krzysztof | Suraj, Zbigniew

Article Type: Research Article

Abstract: This paper presents an approach to discovering concurrent models from data tables using the ROSECON software system. The acronym ROSECON comes from "ROugh SEts and CONcurrency". The models created using ROSECON have the form of Coloured Petri Nets. The ROSECON system is based on the rough set theory. The models derived by ROSECON can be used to determine different properties concerning structures and behaviours of systems. Running examples illustrate some directions one might take in the study of behavioural patterns in information system tables.

Keywords: rough set tools, Coloured Petri Nets, software systems

Citation: Fundamenta Informaticae, vol. 60, no. 1-4, pp. 251-268, 2004