Computer Science
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ISSN 1508-2806
e-ISSN: 2300-7036
Call number
Volume
Vol. 4
Date
2002
Description
Journal
Computer Science
AGH University Press (2004-)
ISSN: 1508-2806 e-ISSN: 2300-7036
ISSN: 1508-2806 e-ISSN: 2300-7036
journal.volume.project
Contains
Journal Issues
Articles
A cellular automata models of evolution of transportation networks
(Wydawnictwa AGH, 2002) Topa, Paweł; Paszkowski, Mariusz
We present a new approach to modelling of transportation networks. Supply of resources and their influence on the evolution of the consuming environment is a principal problem considered. We present two concepts, which are based on cellular automata paradigm. In the first model SCAMAN (Simple Cellular Automata Model of Anastomosing Network), the system is represented by a 2D mesh of elementary cells. The rules of interaction between them are introduced for modelling of the waterflow and other phenomena connected with anastomosing river. Due to limitations of SCAMAN model, we introduce a supplementary model. The MANGraCA (Model of Anastomosing Network with Graph of Cellular Automata) model beside the classical mesh of automata, introduces an additional structure: the graph of cellular automata, which represents the network pattern. Finally we discuss the prospective applications of the models. The concepts of future implementation are also presented.
Distorted pattern recognition and analysis with the help of IE(f] graph representation
(Wydawnictwa AGH, 2002) Sędziwy, Adam
An algorithm for distorted pattern recognition is presented. It's generalization of M. Flasiński results (Pattern Recognition, 27, 1-16, 1992). A new formalism allows to make both qualitative and quantitive distortion analysis. It also enlarges parser flexibility by extending the set of patterns which may be recognized.
Semigroups, groups and grammar inference problem
(Wydawnictwa AGH, 2002) Sokolicki, Zbigniew
In the paper we analyse a problem of inferring a grammar from a given sample of a language. We try to present an algebraic formalism capable of describing the issue. We consider two cases: a case of inferring canonical finite-state grammars, and a case of inferring general grammars. In both cases we define a semigroup structure. Finally we look at the possibility of getting a structure of a group.
Time extensions of Petri nets for modelling and verification of hard real-time systems
(Wydawnictwa AGH, 2002) Samolej, Sławomir; Szmuc, Tomasz Bartłomiej
The main aim of the paper is a presentation of time extensions of Petri nets appropriate for modelling and analysis of hard real-time systems. It is assumed, that the extensions must provide a model of time flow, an ability to force a transition to fire within a stated timing constraint (the so-called the strong firing rule), and timing constraints represented by intervaIs. The presented survey includes extensions of classical Place/Transition Petri nets, as welI as the ones applied to high-level Petri nets. An expressiveness of each time extension is illustrated using simple hard real-time system. The paper includes also a brief description of analysis and verification methods related to the extensions, and a survey of software tooIs supporting modelling and analysis of the considered Petri nets.
Zagadnienie bezpieczeństwa komunikacji w systemie CORBA
(Wydawnictwa AGH, 2002) Byrski, Jędrzej
CORBA standard defines the mechanisms of shearing services. The key rule plays ORB (Object Request Broker) which enables location of suitable server and transparent communication between client and server. This paper presents problems connected with security during communication between ORB systems. In the CORBA system the objects are identified by IOR (Interoperable Object Reference). For TCP/IP it contains IP server address, port and object key. Filtration may use such information as: type of communicate, IP address of client, object key to which client wants to access, type of operation, clients principal. In proposed implementation the firewall works as CORBA server and cooperates with halfbridge. It is registered in ORB system and provides the controlling functions for entering packages by IDL interface. In the paper also the structure of filtering module is presented. Its main part is ACL (Access Control List) with rules of access. The performance evaluation results are also presented.