Chaotic dynamics in a simple bouncing ball model

We study dynamics of a ball moving in gravitational field and colliding with a moving table. The motion of the limiter is assumed as periodic with piecewise constant velocity - it is assumed that the table moves up with a constant velocity and then moves down with another constant velocity. The Poincare map, describing evolution from an impact to the next impact, is derived and scenarios of transition to chaotic dynamics are investigated analytically.Comment: LaTeX, 11 pages, 7 figure

Sizes of flaring kernels in various parts of the H-alpha line profile

In this paper we present new results of spectraphotometrical investigations of the flaring kernels sizes and their intensities measured simultaneously in various parts of the H-alpha line profile. Our investigations were based on the very high temporal resolution spectral-imaging observations of the solar flares collected with Large Coronagraph (LC), Multi-channel Subtractive Double Pass Spectrograph and Solar Eclipse Coronal Imaging System (MSDP-SECIS) at Bialkow Observatory (University of Wroclaw, Poland). We have found that the areas of the investigated individual flaring kernels vary in time and in wavelengths as well as the intensities and areas of the H-alpha flaring kernels decreased systematically when observed in consecutive wavelengths toward the wings of the H-alpha line. Our result could be explained as an effect of the cone-shaped lower parts of the magnetic loops channeling high energy particle beams exciting chromospheric plasma.Comment: Paper accepted to print in Annales Geophysicae (Special Issue: SOHO 20 Solar Conference); 6 pages, 7 figure

Variations of flaring kernel sizes in various parts of the H-alpha line profile

We analyze the temporal variations of the sizes and emission intensities of thirtyone flaring kernels in various parts of the H{\alpha} line profile. We have found that the areas of all kernels decrease systematically when observed in consecutive wavelengths toward the wings of the H{\alpha} line, but their areas and emission intensity vary in time. Our results are in agreement with the commonly accepted model of the glass-shaped lower parts of the magnetic flaring loops channelling high energy variable particle beams toward the chromospheric plasma. High time resolution spectral-imaging data used in our work were collected using the Large Coronagraph and Horizontal Telescope equipped with the Multi-channel Subtractive Double Pass Spectrograph and the Solar Eclipse Coronal Imaging System (MSDP-SECIS) at the Bia{\l}k\'ow Observatory of the University of Wroc{\l}aw, Poland

Bouncing ball dynamics: simple model of motion of the table and sinusoidal motion

Nonlinear dynamics of a bouncing ball moving vertically in a gravitational field and colliding with a moving limiter is considered and the Poincar\'e map, describing evolution from an impact to the next impact, is described. Displacement of the table is approximated in one period by four cubic polynomials. Results obtained for this model are used to elucidate dynamics of the standard model of bouncing ball with sinusoidal motion of the limiter.Comment: LaTeX, 23 pages, 5 figure

Real-Time Statistical Speech Translation

This research investigates the Statistical Machine Translation approaches to translate speech in real time automatically. Such systems can be used in a pipeline with speech recognition and synthesis software in order to produce a real-time voice communication system between foreigners. We obtained three main data sets from spoken proceedings that represent three different types of human speech. TED, Europarl, and OPUS parallel text corpora were used as the basis for training of language models, for developmental tuning and testing of the translation system. We also conducted experiments involving part of speech tagging, compound splitting, linear language model interpolation, TrueCasing and morphosyntactic analysis. We evaluated the effects of variety of data preparations on the translation results using the BLEU, NIST, METEOR and TER metrics and tried to give answer which metric is most suitable for PL-EN language pair.Comment: machine translation, polish englis

Poland has taken on an unprecedented leadership role over the EU’s foreign policy during the Ukraine crisis

The EU formally adopted new sanctions against Russia on 8 September which will come into force over the next few days. Elizabeth Radziszewski assesses the role of Poland during the Ukraine crisis and how the country’s foreign policy sits with the EU’s response to Russia. She writes that Poland has taken on an unprecedented leadership role during the crisis, which could be enhanced by the appointment of Poland’s Prime Minister, Donald Tusk, as the next President of the European Council