Wyniki wyszukiwania - Biblioteka Nauki

1

CO-MOVEMENT (SUB-) INDICATOR AS THE MEASUREMENT OF THE SYNCHRONY OF EA AND VISEGRAD GROUP COUNTRIES

100%

Poměnková J. , Klejmová E. , Malach T.

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nr 3

231 – 251

EN

The paper deals with the construction of a co-movement indicator suitable for assessing the synchrony between countries. The indicator is represented as a time series and its construction is based on a reconstruction of a co-spectrum measure from the time-frequency to the time domain. We use the statistically significant part of the power wavelet co-spectrum for pairs of countries. An advantage of the newly proposed co-movement indicator is a possibility to construct sub-indicators which correspond to the predefined frequency range, e.g. business cycle frequencies. In such a way we can obtain a decomposition of the co-movement indicator (covering all frequencies) into, for example, short-run cycles, medium and long business cycles and long-run cycles. The proposed methodology is demonstrated on the US and EA monthly data of industrial production index in 1991 – 2018. A further application is performed on the EA and Visegrad Group Countries with the same data type and time range.

2

Evolutionary algorithm for market simulations

72%

Stańczak J.

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tom z. 169

163-172

EN

Evolutionary algorithms (EA) have recently become not only tools for efficient optimization of very difficult problems, but also are applied to simulate behavior of different kinds of systems, among them also games, economic systems and markets. This new domain of EA applications is known as Agent-Based Computational Economics (ACE). This article describes two applications of EA to simple market simulations. The main aim of EA in this approach is to find (sub-) optimal strategies of behavior for the participants of that market game. The first example is a simple market with only several participants and one product, well known as an instance of Cournot oligopoly game. The second example is more complicated and describes a market of permits for CO2 emission, created by the Kyoto Protocol and introduces to the simple Walrasian model the influence of calculated on-line permits prices.

3

Stopping criteria for a general model of genetic algorithm

58%

Studniarski M.

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tom z. 169

173-181

EN

We consider a general Markov chain model of genetic algorithm described in [3], Chapters 5 and 6. For this model, we establish an upper bound for the number of iterations which must be executed in order to find an optimal (or approximately optimal) solution with a prescribed probability. For the classical genetic algorithm with bitwise mutation, our result reduces to the main theorem of [1] in the case of one optimal solution, and gives some improvement over it in the case of many optimal solutions.

4

Stochastic Dynamics of Evolutionary Multi-Agent Systems

58%

Byrski A. , Schaefer R.

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tom z. 169

27-34

EN

The refined model for the biologically inspired agent-based computation system EMAS conformed to BDI standard is presented. The considerations are based on the model of the system dynamics as the stationary Markov chain already presented. In the course of paper space of the system states is modified in order assure state coherency and set of actions is simplified. Such a model allows for better understanding the behavior of the proposed complex systems as well as their limitations.

5

An Application of Hierarchical Genetic Strategy in sequential scheduling of permutated independent jobs

58%

Kołodziej J. , Rybarski M.

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tom z. 169

95-102

EN

The aim of this paper is to present an implementation of Hierarchic Genetic Strategy (HGS) in solving the Permutation Flowshop Scheduling Problem (PFSP). We defined a hierarchic scheduler based on HGS structure for the exploration of the wide and complicated optimization landscape studied by Reeves. The objective of our work is to examine several variations of HGS operators in order to identify a configuration of operators and parameters that works best for the problem. From the experimental study we observed that HGS implementation outperforms existing schedulers in many of considered instances of a static benchmark for the problem.

6

MOSFET parameter extraction with EKV model

58%

Bartnik Ł. , Arabas J.

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tom z. 169

9-17

EN

This paper reports results of an ongoing research on MOSFET parameter extraction using the EKV model. This work continues efforts in finding the best method for efficient and robust parameter extraction based on voltage-current structure characteristics. In the extraction process, voltage-current characteristics are matched by the characteristics generated by the model. Values of parameters for which the best match is observed are the result of the extraction. The extraction process is considered an optimization problem, which is then solved by an evolutionary algorithm followed by the Nelder-Mead simplex. The influence of the measurement error on the extraction results is investigated experimentally.

7

Wykorzystanie czujników z polifluorku winylidenu w diagnostyce urządzeń elektrycznych.

58%

Kisiel A. , Woźny L. , Mazurek B.

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1998

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tom Vol. 34, nr 10

161-164

PL

Celem przedstawionej pracy było skonstruowanie czujników piezoelektrycznych z materiałów polimerowych i sprawdzenie możliwości wykorzystania ich do rejestrowania emisji akustycznej (EA) z urządzeń elektrycznych. Badane czujniki wykonano z polifluorku winylidenu (PVDF), formowanego w postaci przewodów. Przetworniki te wykorzystano do pomiarów emisji akustycznej z transformatora wysokiego napięcia i prostownika wysokonapięciowego. Zaobserwowano nietypowe rozkłady przestrzenne i czasowe tempa EA, co może świadczyć o pewnych wadach konstrukcyjnych lub starzeniowych tych urządzeń. W pomiarach EA szczególną uwagę zwrócono na wpływ ekranowania w celu ochrony przed zakłóceniami pochodzącymi od promieniowania elektromagnetycznego, generowanego podczas wyładowań elektrycznych. Stwierdzono, że wpływ ekranowania na mierzoną emisję akustyczną jest bardzo wyraźny, często umożliwiający rejestrację sygnałów EA.

EN

Ultrasonic transducer is one of the most important elements of the acoustic emission (AE) detection system. In this paper the construction of piezoelectric polimere transducers and the possibility of their application to measurement of AE signals from electric devices are presented. Detectors were made from piezoelectric polyfluorine winylidene (PVDF) wire. The were used for measurements of acoustic emission pulses detected from high-voltage transformer and from high-voltage rectifier. The untypical space and time distributions of AE rate were observed. They might be caused by occurrence of constructional faults, some defects or ageing processes of these devices. During measurement it was found that precise cables and detectors shielding against electromagnetic radiation induced after electric breakdown is very important. The significant influence of shielding, especially of detectors AE, on measured acoustic emission signals rate was revealed.