Last issue
2016 (vol. 26) - Number 4


Andrzej Ruszewski:

Practical and asymptotic stability of fractional discrete-time scalar systems described by a new model



D. Krokavec, A. Filasova, P. Liscinsky:

On fault tolerant control structures incorporating fault estimation



Sundarapandian Vaidyanathan:

Hyperchaos, adaptive control and synchronization of a novel 4-D  hyperchaotic system with two quadratic nonlinearities



H. Górecki, M. Zaczyk:

Analytic solutions of transcendental equations with application to automatics



F. Mnif:

Predictor-based stabilization for chained form systems with input time delay



S. Daniar, R. Aazami, M. Shiroei:

Multivariable predictive control considering time delay for load-frequency control in multi-area power systems



T. Kaczorek:

Analysis and comparison of the stability of discrete-time and continuous-time linear systems



M. Rachik, M. Lhous:

An observer-based control of linear systems with uncertain parameters



L. Malinski:

Identification of stable elementary bilinear time-series model



V.V. Huynh:

New observer-based control design for mismatched uncertain systems with time-delay




ACS Abstract:

1995 (Volume 4)
Number 1/2
1. The programmed grammars and automata as tools for a construction of analytic expert systems
2. Optimal control of discrete distributed systems with delays in the control: the finite horizon case
3. Multivariable nonlinear system identification by radial basis function neural networks
4. Repetitive regulator approximation
5. Eigenvalue assignment and exponential stability in discrete-time systems
6. A comparative study of ranking fuzzy sets deffined by a neural network algorithm - justification for a centroidal method
7. Digital relaying in power system using fuzzy set theory
8. Logical foundations for knowledge-based control systems. Part II: Representation of states, transformations and analysis of theoretical properties


The programmed grammars and automata as tools for a construction of analytic expert systemsDownload full PDF article
M.Flasiñski
(Jagiellonian University, Poland)

The new pattern recognition- and formal linguistics- based approach for constructing analytic expert systems is proposed. The expert systems implemented with this approach are able to diagnose and control hard real-time distributed computerized systems. The practical usefulness of a methodology proposed has been positively verified by an application for constructing a real-time expert system for a high energy physics experiment. The proposed formalisms are compatible with rule-based systems paradigm.

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Optimal control of discrete distributed systems with delays in the control: the finite horizon caseDownload full PDF article
Mostafa Rachik
(Faculté des Sciences Ben M'sik, Morocco)
Jamila Karrakchou
(Ecole Mahammadia d'Ingénieurs, Morocco)

The linear quadratic optimal control of discrete-time distributed systems with delays in the control is considered. A new approach for solving this problem is presented. It is based on the construction of an appropriate Hilbert space structure. In order to illustrate the theory an example of diffusion system is given.

keywords: difference equation, diffusion system, discrete distributed systems, linear quadratic optimal control, optimal control.

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Multivariable nonlinear system identification by radial basis function neural networksDownload full PDF article
Shaohua Tan
(National University of Singapore, Singapore)
Jianbin Hao and Joos Vandewalle
(Katholieke Universiteit Leuven, Belgium)

This paper addresses the problem of identifying nonlinear discrete-time multivariable systems using radial-basis-function neural networks. A recursive identification scheme is proposed that first builds recursively a RBF (Radial-Basis-Function) neural net model structure and then uses a stable recursive weight updating algorithm to modify the weights. The convergence of the scheme is established using the Lyapunov stability theory. The scheme is also applied to an illustrative example to show its efficacy.

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Repetitive regulator approximationDownload full PDF article
Krzysztof Nowosad
(Warsaw University of Technology, Poland)

In this paper the repetitive control algorithm is considered. It is shown that the repetitive regulator is the limit case of this control algorithm when the sampling frequency becomes infinite.

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Eigenvalue assignment and exponential stability in discrete-time systemsDownload full PDF article
Jerzy Tokarzewski
(Military University of Technology, Poland)

The eigenvalue assignment problem in a linear sampled-data system using a continuous reduced-dimensional state estimator and constant gain feedback (in a double feedback loop configuration) from the estimated state is discussed. The proposed design procedure gives freedom in the simultaneous selection of poles of the closed-loop discrete-time system and of the sampling frequency. Moreover, the procedure enables one to obtain exponentially stable (in a wide range of sampling frequencies) closed-loop discrete-time system and in consequence to take into account intersampling behaviour of continuous-time signals (e.g., the output signal). Appropriate quantitative stability conditions are provided. The design procedure is illustrated by a simple numerical example.

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A comparative study of ranking fuzzy sets deffined by a neural network algorithm - justification for a centroidal methodDownload full PDF article
Les M. Sztandera
(Philadelphia College of Textiles and Science, USA)

Ranking fuzzy subsets is an important event in dealing with fuzzy decision problems in many areas, such as social sciences, management sciences and engineering. However, until now, no thorough investigation has been made to evaluate the relative performance of all the ranking methods, and to analyze the differences between these methods for a particular application.

A recent breakthrough calls on a neural network algorithm, Fuzzy CID3 Algorithm, [109,111], which learns the needed membership functions from a set of training examples to differentiate between classes.

It is the purpose of this paper to evaluate and analyze the performance of available methods of ranking fuzzy subsets on a set of selected examples that cover possible situations we might encounter as defining fuzzy subsets at each node of a neural network. Through this analysis, suggestions as to which methods have better performance for utilization in neural network architectures, as well as criteria for choosing an appropriate method for ranking in corresponding fuzzy trees will be made.

keywords: fuzzy multi-attribute decision making, evaluation of fuzzy ranking methods, neural network architecture.

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Digital relaying in power system using fuzzy set theoryDownload full PDF article
Bogdan Kasztenny
(Technical University of Wroc³aw, Poland)

This paper presents a digital relay scheme for the primary protection of power system. A multi-criteria algorithm is developed based on fuzzy sets for the decision making part of the scheme. The cost of wrong decision-making and the amount of information inflow are used along with several standard criteria to improve the reliability of the protection. The power transformer protection has been chosen as a test example. It is shown that the proposed scheme, if properly tuned, can enhance the sensitivity and selectivity of the digital relay and mitigate problems associated with conventional relay schemes.

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Logical foundations for knowledge-based control systems. Part II: Representation of states, transformations and analysis of theoretical propertiesDownload full PDF article
Antoni Ligêza
(St. Staszic Technical University of Mining and Metallurgy, Poland)

This is the second part of a two-part paper. In Part I, a brief outline of a knowledge representation language based on simplified first order predicate calculus is presented. A restricted logical calculus, based on classical first-order logic is proposed. An idea of generalization among logical formulae is defined. A formal reasoning method, so-called backward dual resolution, is introduced; the method is aimed at performing reasoning in an efficient manner and can be applied to reasoning about states and situations, checking if preconditions of transformation rules are satisfied, and to the verification of some theoretical properties of knowledge-based systems.

In this part, an application of the introduced formalism to knowledge-based representation of physical states of dynamic systems is proposed. A generic scheme of state transformation rules is outlined. Definitions of properties such as determinism, completeness, conservativity, and other are introduced and an idea of potential correctness of knowledge formalization is given. Due to general format of the proposed formalization, the class of potential applications is very large. The applications of specific interest of the proposed formalism include design and implementation of knowledge-based control systems and modelling the behaviour of certain complex relational systems having no analytical models in the form of differential/difference equations, as well as analysis of theoretical properties of knowledge-based dynamic systems. Simple application examples are enclosed.

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