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1

Możliwości optymalizacji procesu transportowego z wykorzystaniem sztucznej inteligencji

Wróbel M., Wojda P.

Journal of TransLogistics

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2018

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Vol. 4, nr 1

197--204

PL

Artykuł przedstawia zastosowanie sztucznej inteligencji w optymalizacji procesu transportowego. Omówiono w nim istotę procesu transportowego oraz jego etapy. Zaprezentowano praktyczne zastosowania sztucznej inteligencji obecnie wykorzystywanej, a także prototypy nowych urządzeń. W artykule skupiono się na przedstawieniu korzyści płynących z wprowadzania systemów inteligentnych oraz szansach rozwoju logistyki.

EN

The article presents the application of artificial intelligence in optimization of transport process. The essence of the transport process and its stages were described. Currently used practical application of artificial intelligence and prototypes of new devices were presented. The article is focused on presenting benefits from implementing intelligent systems and chances of logistics development.

2

General dynamic projecting of maxwell equations

Wojda P., Leble S.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2017

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Vol. 21, No 2

85--96

EN

A complete – system of Maxwell equations is splitting into independent subsystems by means of a special dynamic projecting technique. The technique relies upon a direct link between field components that determine correspondent subspaces. The explicit form of links and corresponding subspace evolution equations are obtained in conditions of certain symmetry, it is illustrated by examples of spherical and quasi-one-dimensional waves.

3

Rozwój systemów informatycznych wykorzystywanych przez operatorów logistycznych

Wojda P.

Journal of TransLogistics

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2017

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Vol. 3, nr 2

185--190

PL

Artykuł przedstawia podział systemów logistycznych oraz funkcjonowanie systemów informatycznych u operatorów logistycznych. Omówiono w nim możliwości rozwoju systemów, a także nowe systemy wprowadzane w celu uzyskania przewagi konkurencyjnej na rynku. Prezentuje korzyści wynikające z rozwoju systemów informatycznych.

EN

The article presents the division of logistic systems and the operation of systems information in logistic operator. It discusses the possibilities of developing systems and new systems introduced in order to obtain a competitive advantage in the market. Presents the benefits from the development of information systems.

4

Artificial Neural Network in Forecasting the Churn Phenomena Among Costumers of IT and Power Supply Services

Wojda P., Nowicki K.

Automatyka, Elektryka, Zakłócenia

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2017

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Vol. 8, Nr 3(29)

34--41

EN

This paper presents an attempt to use an artificial neural network to investigate the chum phenomenon among the customers of a telecommunications operator. An attempt was made to create a data model based on the customer lifetime value (CLV) rather than on activity alone. A multilayered artificial neural network was used for the experiments. The results yielded a 99% successful identification rate for customers in no danger of leaving, while only 57% of those identified as in danger of leaving actually did so and stopped using the company's services.

PL

W artykule przedstawiono próbę wykorzystania sztucznej sieci neuronowej (ang. Artificial Neural Network - ANN) do badania zjawiska churn wśród klientów operatora telekomunikacyjnego. Podjęto wysiłek stworzenia modelu danych opartego na całkowitej wartości klienta (ang. Customer Lifetime Value - CLV), a nie tylko na jego aktywności. Do przeprowadzenia eksperymentów wykorzystano wielowarstwową sztuczną sieć neuronową. Uzyskano 99-procentową skuteczność identyfikowania klientów nieobjętych ryzykiem odejścia. W rzeczywistości tylko 57% klientów objętych ryzykiem odejścia zrezygnowało z usług firmy.

5

A high-accuracy method of computation of X-ray waves propagation through an optical system consisting many lenses

Kshevetskii S., Wojda P.

TASK Quarterly : scientific bulletin of Academic Computer Centre in Gdansk

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2016

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Vol. 20, No 2

171--186

EN

The propagation of X-ray waves through an optical system consisting of many X-ray refractive lenses is considered. Two differential equations are contemplated for solving the problem for electromagnetic wave propagation: first – an equation for the electric field, second – an equation derived for a complex phase of an electric field. Both equations are solved by the use of a finite-difference method. The simulation error is estimated mathematically and investigated. The presented results for equations show that in order to establish a high accuracy computation a much smaller number of points is needed to solve the problem of X-ray waves propagation through a multi-lens system when the method for the second equation is used. The reason for such a result is that the electric field of a wave after passing through many lenses is a quickly oscillating function of coordinates, while the electric field phase is a quickly increasing, but not oscillating function. Therefore, a very detailed difference grid, which is necessary to approximate the considered electric field can be replaced by not such a detailed grid, when computations are made for the complex wave of the electric field. The simulation error of both suggested methods is estimated. It is shown that the derived equation for a phase function allows efficient simulation of propagation of X-rays for the multi-lens optical system.

6

Efficient quadrature for fast oscillating integral of paraxial optics

Kshevetskii S., Wojda P.

Mathematica Applicanda

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2015

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Vol. 43, No. 2

253--267

EN

The study concerns the determination of quadrature for the integral solution of the paraxial wave equation. The difficulty in computation of the integral is associated with the rapid change of the integrand phase. The developed quadrature takes into account the fast oscillating character of the integrand. The presented method is an alternative to the commonly used methods based on the use of the Fourier transform. The determination of the quadrature is discussed on the example of the integral arisen in the theory of propagation and focusing on hard X-rays waves. Due to the generality of the presented quadrature, it may also be applied to issues related to standard optics and acoustics.

PL

Praca jest poświęcona wyznaczaniu kwadratury dla rozwiązań całkowych równania przewodnictwa cieplnego z zespolonym potencjałem. Trudność w wyznaczaniu tego typu całek jest związana z szybkimi oscylacjami funkcji całkowanej. Prezentowana metoda jest alternatywa dla powszechnie stosowanej metody opartej o zastosowanie transformacji Fouriera. Sprecyzowanie kwadratury jest przedyskutowane na przykładzie całek występujących przy badaniu teorii propagacji i skupiania promieniowania rentgenowskiego. Dzięki ogólności prezentowanej kwadratury, może być ona także zastosowana do zagadnień związanych z optyką i akustyką.

7

Unusual streaming in chemically reacting gases

Perelomova A., Wojda P.

Hydroacoustics

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2011

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Vol. 14

189-198

EN

Nonlinear stimulation of the vorticity mode caused by losses in the momentum of sound in a chemically reacting gas, is considered. The instantaneous dynamic equation which describes the nonlinear generation of the vorticity mode, is derived. It includes a quadratic nonlinear acoustic source. Both periodic and aperiodic sound may be considered as the origin of the vorticity flow. In the non-equilibrium regime of a chemical reaction, sound and its nonlinear effects behave unusual. There may exist vortices whose direction of rotation is opposite to that of the vortices in the standard thermoviscous flows. This is illustrated by example relating to periodic sound. The theory and examples consider cases of both equilibrium and non-equilibrium regime of a chemical reaction.

8

Studies of Nonlinear Sound Dynamics in Fluids Based on the Caloric Equation of State

Perelomova A., Wojda P.

Archives of Acoustics

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2010

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Vol. 35, No. 4

619-633

EN

The sound speed and parameters of nonlinearity B/A, C/A in a fluid are expressed in terms of coefficients in the Taylor series expansion of an excess internal energy, in powers of excess pressure and density. That allows to conclude about features of the sound propagation in fluids, the internal energy of which is known as a function of pressure and density. The sound speed and parameters of nonlinearity in the mixture consisting of boiling water and its vapor under different temperatures, are evaluated as functions of mass concentration of the vapor. The relations analogous to that in the Riemann wave in an ideal gas are obtained in a fluid obeying an arbitrary equation of state. An example concerns the van der Waals gases. An excess pressure in the reflected wave, which appears when standard or nonlinear absorption in a fluid takes place, is evaluated in an arbitrary fluid.

9

Acoustic streaming caused by some types of aperiodic sound. Buildup of acoustic streaming

Perelomova A., Wojda P.

Archives of Acoustics

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2009

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Vol. 34, No. 4

625-639

EN

The analysis of streaming caused by aperiodic sound of different types (switched on at transducer sound or sound determined by initial conditions) is undertaken. The analysis bases on analytical governing equation for streaming Eulerian velocity, which is a result of decomposition of the hydrodynamic equations into acoustic and non-acoustic parts. Its driving force (of acoustic nature) represents a sum of two terms; one is the classic one, which, being averaged over the sound period, coincides with the well-known expression. The second one depends on the periodicity of the sound; at the axis of beam propagation it becomes exactly zero after averaging for the strictly periodic sound but differs from zero for other acoustic waves. Both terms are nonlinear and proportional to the standard attenuation due to shear, bulk viscosities and thermal conductivity. Numerical analysis reveals a qualitative agreement with experimental data. Some theoretical conclusions concerning features of streaming caused by sound determined by initial conditions, are made.