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1

Power penalty caused by Stimulated Raman Scattering in WDM Systems

Pietrzyk S., Szczęsny W., Marciniak M.

Journal of Telecommunications and Information Technology

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2000

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nr 1-2

52-58

EN

In this paper we present results of an investigation into the power penalty introduced by Stimulated Raman Scattering (SRS) in WDM systems with concentration on application of dispersion-shifted single-mode optical fibres (G.653) and unequal channel allocation schemes. System parameters based on ITU-T Recommendation G.692 and analytic formulas were used in calculations. It is shown that SRS does present a practical limitation to the multichannel systems. We also indicate limitations of the G.692 Recommendation and we point at directions of study in the area of nonlinear phenomena and multichannel systems.

2

Impact of nonlinear optical phenomena on dense wavelength division multiplexed transmission in fibre telecommunication systems

Szczęsny W., Marciniak M.

Journal of Telecommunications and Information Technology

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2000

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nr 1-2

61-65

EN

In the paper results of analysis of nonlinear phenomena in optical fibres: Self-Phase Modulation, Cross-Phase Modulation, Four-Wave Mixing and Stimulated Raman Scattering and their influence on Dense-Wavelength Division Multiplexed system performance are reported. Different nonuniform optical channel allocation schemes based on ITU Recommendation G.692 100 GHz frequency grid are compared with uniform channel distribution. The level of nonlinear cross-talk is determined for different levels of the total optical power. As an example a 10 Gbit/s D-WDM dispersion-shifted single mode fibre link with dispersion-compensating fibres is envisaged. The directions for optimization of the system design in view of actual international standardization trends are pointed out.

3

Detecting rows and columns of contingency table, which outlie from a total positivity pattern

Szczęsny W.

Control and Cybernetics

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2000

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Vol. 29, no 4

1059-1073

EN

It is known that the procedure called Grade Correspondence Analysis (GCA) transforms any bivariate contingency table into an approximation of table with a very regular positive dependence, called total positivity of order two (TP2). This fact is reminded in Sections 2 and 3, illustrated there by the GCA transformation of an artificial contingency table [T_8x6]. A search for rows and/or columns of table [T_8x6], which most strongly outlie from the TP2 pattern, is described in Section 4. Section 5 presents the outliers found in three large contingency tables, containing the occupational mobility data from Britain and Poland and the parliamentary election data from Poland.

4

Statistical analysis of the departure from proportionality in the 1991 election in Poland

Bondarczuk Z., Ciok A., Szczęsny W.

Matematyka Stosowana : matematyka dla społeczeństwa

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1993

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Nr 36

115--128

EN

New statistical measures of departure from proportional representation, introduced in Bondarczuk, Kowalczyk, Pleszczyńska and Szczęsny (1992), are applied to the results of the 1991 election to the Polish Parliament. A pair of indices is used to evaluate departures from proportionality between number of votes and number of elects. One index indicates general strength of the departures, the other one indicates to which extent they are due to overrepresentation increasing (or decreasing) with number of votes. The indices are corrected in order to eliminate the influence of the distribution of votes, number of votes and size of representation. The correction is based on intensive computer simulation. The analysis of the election data showed significant overrepresent ation of six parties (or group of parties forming election committees) with maximal numbers of votes. On the other hand, in the subpopulation of voters formed by these six parties only, the departure from proportionality is very small.