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Genetic and combinatorial algorithms for optimal sizing and placement of active power filters

Maciążek M., Grabowski D., Pasko M.

International Journal of Applied Mathematics and Computer Science

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2015

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Vol. 25, no. 2

269--279

EN

The paper deals with cost effective compensator placement and sizing. It becomes one of the most important problems in contemporary electrical networks, in which voltage and current waveform distortions increase year-by-year reaching or even exceeding limit values. The suppression of distortions could be carried out by means of three types of compensators, i.e., passive filters, active power filters and hybrid filters. So far, passive filters have been more popular mainly because of economic reasons, but active and hybrid filters have some advantages which should cause their wider application in the near future. Active power filter placement and sizing could be regarded as an optimization problem. A few objective functions have been proposed for this problem. In this paper we compare solutions obtained by means of combinatorial and genetic approaches. The theoretical discussion is followed by examples of active power filter placement and sizing.

2

Internet shopping optimization problem

Błażewicz J., Kovalyov M. Y., Musiał J., Urbański A. P., Wojciechowski A.

International Journal of Applied Mathematics and Computer Science

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2010

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Vol. 20, no 2

385-390

EN

A high number of Internet shops makes it difficult for a customer to review manually all the available offers and select optimal outlets for shopping. A partial solution to the problem is brought by price comparators which produce price rankings from collected offers. However, their possibilities are limited to a comparison of offers for a single product requested by the customer. The issue we investigate in this paper is a multiple-item multiple-shop optimization problem, in which total expenses of a customer to buy a given set of items should be minimized over all available offers. In this paper, the Internet Shopping Optimization Problem (ISOP) is defined in a formal way and a proof of its strong NP-hardness is provided. We also describe polynomial time algorithms for special cases of the problem.

3

Badania możliwości wyboru optymalnej zmiennej obserwowanej jako zmiennej predykcyjnej w zbiorze danych o rynkach finansowych

Wiliński A., Czapiewski P.

Metody Informatyki Stosowanej

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2008

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nr 1 (Tom 13)

159-174

EN

The paper presents the results of computer simulations performed using the historical quotes on several securities (WIG20, S&P500, Dow Jones, DAX, EUR/USD, gold, oil, etc.) in order to analyse the possibility of finding such variables, that can be explained in terms of the others better, than the rest. It is assumed, that the ultimate goal of every investment strategy is finding the opportunity of gaining a financial profit (always considering the risk). Such opportunity is being sought by investigating the possibility of using each variable (each security) in turn as the one to be predicted. In order to reach that goal, authors use several variants of one of the algorithms belonging to the. Group Method of Data Handling (GMDH), namely the combinatorial algorithm. The results reveal some interesting features of regression models, indicating the prospect of further applications of the method.

4

Distributed Password for Quorum and Veto

Dobrzański W., Srebrny M.

Scientific Issues of Jan Długosz University in Częstochowa. Mathematics

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2000/2001

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Vol. 8

25--31

EN

A simple algorithm for sharing a secret with some nonmonotone access structures will be presented. This is achieved by splitting a secret password, represented by a large prime number, between n participants in such a way that only by pooling a qualified set of shares one can recover the original password. Executing the power of veto in addition to a qualified set provides a nonqualified (forbidden) superset. The cryptographic power of our algorithm is based on computational hardness of the integer factorization.