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1
Content available Installation and testing the lofar software on ACC Cyfronet cluster Prometheus
Kuligowska Elżbieta, Czuchry Maciej, Chyży Krzysztof, Kundera Tomasz, Roskowiński Carole, Dzielak Marta A.
Computer Science
|
2019
|
Vol. 20 (2)
165--177
EN
We present the actual status and the most important issues related to the installation of the data reduction LOFAR software on high power computer Prometheus located in ACC Cyfronet. We refer to the software itself as well its practical use cases in the context of the scientific tool and the detailed installation/testing methodology. We address most typical challenges and problems that occurred during our attempts to set up the complete and ready-to-use LOFAR environment (including not only programs, but also libraries, scripts and other additional tools) on non-standard (cluster-type) computing system. The result of these works is then briey summarized. We also discuss the is- sues related to LOFAR documentation, maintenance, distribution and further development. Finally, we propose some future improvements.
2
Content available remote Skanowanie Kopernika
Figurski M., Pazderski E., Nykiel G., Wolak P., Przyborski M.
Geodeta : magazyn geoinformacyjny
|
2017
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nr 11
8--15
3
Content available remote Pomiar szumu w szumie metodą korelacyjną
Lal-Jadziak J.
Przegląd Elektrotechniczny
|
2016
|
R. 92, nr 11
179--182
PL
Celem artykułu jest przedstawienie korelacyjnych procedur pomiaru sygnałów losowych. Procedury te muszą sprostać wymaganiom pomiaru słabych sygnałów (np. w radioastronomii lub termometrii szumowej) występujących na tle zakłóceń lub umożliwiać pomiar opóźnienia między zakłóconymi sygnałami.
EN
In the article correlation procedures for measuring random signals are considered. These procedures must fulfill requirements for measurement of weak signals (e.g. in radio astronomy or noise thermometry) appearing against the background of noises or enable measurement of the delay between noised signals.
4
Content available remote Prospects for Scrutiny of Pulsars with Polish Part of LOFAR
Błaszkiewicz L., Lewandowski W., Krankowski A., Kijak J., Koralewska O., Dąbrowski B. P.
Acta Geophysica
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2016
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Vol. 64, no. 1
293--315
EN
LOFAR (LOw Frequency ARray) is a new generation digitally controlled radio telescope consisting of phased array antenna stations with sensitivity, bandwidth, range of frequency, and digital processing power that makes it an excellent tool for observations of pulsars. This interferometric instrument is able to work in a single-station mode as well as in group-of-selected-stations mode. This article discusses the great opportunity for conducting unique and independent research of pulsar sources with the three LOFAR stations located in Poland and maintained by the POLFAR consortium.
5
Content available Korelatory w zastosowaniach radioastronomicznych
Lal-Jadziak J.
Pomiary Automatyka Kontrola
|
2014
|
R. 60, nr 11
963--965
PL
Celem artykułu jest przedstawienie specyficznych konfiguracji oraz własności korelatorów stosowanych w radioastronomii. Korelatory te muszą sprostać wymaganiom wykrywania słabych sygnałów występujących na tle zakłóceń kosmicznych, atmosferycznych oraz radiowych. W ich układach wejściowych stosuje się kwantowanie sygnałów na kilku poziomach, co jest źródłem degradacji funkcji korelacji. Z uwagi na właściwości statystyczne sygnałów taka degradacja jest akceptowalna a w razie potrzeby może być zmniejszona przez zwiększenie częstotliwości próbkowania.
EN
In the article, specific configurations and properties of correlators applied in radio astronomy are considered. These correlators must meet requirements of detection of weak signals (signal-to-noise ratio -60 to -30 dB) which appear on the floor of cosmic noise, atmospheric and radio interferences. Architectures of XF and FX correlators are presented in. Fig. 1 and Fig. 2, respectively. A basis of the XF correlator performance is formula (1) [4, 6, 10] whereas the FX correlator operates based on formulas (2) – (4) [4, 6, 10]. The first measurement method is called the cross-spectrum via correlation function, the other - the cross-spectrum via Fourier transforms [1]. The XF correlators tend to be simpler, but also less adaptable to more complex requirements. The FX correlators are more efficient for large number of antennas. Besides, they are more readily designed to be robust to RFI. In input circuits of correlators a several-level quantization is applied. It is source of cross-correlation function degradation. Quantization efficiency vs. number of quantization levels and sampling frequency is presented in Tab. 1 [6,10]. The table says that an increase in sampling frequency partly compensates losses due to rough signals quantization. From Tab. 2 and Fig. 4, it follows that a normalized systematic error due to rough quantization of normal signals may be acceptable. As an example, a correlator in Torun Centre for Astronomy (Poland) has XF architecture and contains 3-level quantizers while a modern correlator ALMA (Chile) presented in Fig. 3 has XF architecture as well and contains 3-bit quantizers.
6
Content available Design of a Superconducting Antenna Integrated with a Diplexer for Radio-Astronomy Applications
Donelli M., Febvre P.
Journal of Telecommunications and Information Technology
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2014
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nr 3
113--118
EN
This paper presents the design of a compact frontend diplexer for radio-astronomy applications based on a self complementary Bow-tie antenna, a 3 dB T-junction splitter and two pass-band fractal lters. The whole diplexer structure has been optimized by using an evolutionary algorithm. In particular the problem of the diplexer design is recast into an optimization one by dening a suitable cost function which is then minimized by mean of an evolutionary algorithm namely the Particle Swarm Optimization (PSO). An X band diplexer prototype was fabricated and assessed demonstrating a good agreement between numerical and experimental results.
7
Content available Investigation of Radio Frequency Interference (RFI) Profile and Determination of Potential Astronomical Radio Sources
Hamidi Z. S., Shariff N. N. M.
International Letters of Chemistry, Physics and Astronomy
|
2014
|
Vol. 5
43--49
EN
In this article, we have recognized a Radio Frequency Interference (RFI) sources that can potentially affect for radio astronomical observation. The main objective of this surveying is to test and qualify the potential of radio astronomical sources that can be observed in Malaysia generally. Analysis process focuses on the high sources that contribute the pollution and the significant region that can be considered for astronomical purpose beginning 1-2000 MHz. It was found that 13 individual sources contribute as a noise and mostly are telecommunication and radio navigation applications. We then compared of the RFI profiles based on three different periods in order to observe the variety of the signals. The main regions that still excellent to do an observation are: 13.36 -13.41 MHz (solar), (25.55-25.67) MHz (Jupiter) and (37.50-38.25) MHz (Continuum) respectively. This work is also an initiative of the International Space Weather Initiative (ISWI) project where Malaysia is one of the countries that involve in e-CALLISTO (Compound Astronomical Low Cost Low Frequency Transportable Observatory) network project. Some suggestions are recommended in order to improve the quality of the radio frequency profile.
8
Radiowy wszechświat
Kus A.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2013
|
nr 6
162--168
PL
Przedstawiono historię rozwoju i największe osiągnięcia badań radioastronomicznych. Dużą uwagę poświęcono rozwojowi radioastronomii w Polsce. Wiodącą rolę odgrywają tu dwa ośrodki - Obserwatorium Astronomiczne UJ i Centrum Astronomii UMK CA UMK ma jedyny w Polsce w pełni sprawny 32 m średnicy radioteleskop zaprojektowany i zbudowany w Polsce. Ciągły rozwój bazy aparaturowej następujący dzięki wyjątkowo dobrze rozwiniętej współpracy międzynarodowej tworzy warunki dla prowadzenia badań na poziomie europejskich obserwatoriów. W kontekście wielkich światowych projektów omówiono najnowszy projekt dużego polskiego 100 m radioteleskopu Narodowego Centrum Radioastronomii i Inżynierii Kosmicznej oraz włączenie się Polski do europejskiego projektu LOFAR.
EN
In this paper a development and the greatest achievements of Radio Astronomy are given. On the ground of overall world activity in this field, the Polish contribution is reviewed. Current involvement of Polish Institutes into international research in Radio Astronomy is presented here mostly from the perspective of the Torun Centre for Astronomy 0"Cf A), which operates large 32m diameter radio telescope. This telescope, designed and built in Poland, is one of the best of its class in the world. It has been intensively used for VLBI, pulsar and spectral research. Continuous technical development of the telescope instrumentation, conducted in close cooperation with European observatories, and the scientific results obtained in various research programs, places TCfA well among the European Radio Observatories. The new investment to build a 100m class, fully steerable new generation radio telescope, is well prepared and scientifically motivated.
9
Content available remote User Interaction and Workflow Management in Grid enabled e-VLBI Experiments
Dolata Ł., Okoń M., Stokłosa D., Trocha Sz., Meyer N., Stroiński M., Kaliszan D., Rajtar T., Lawenda M.
Computational Methods in Science and Technology
|
2009
|
Vol. 15, nr 1
95-104
EN
The purpose of this paper is to present the design of the integration of radio-astronomical VLBI experiments with the Grid environment. The current status of the VLBI process is described, and the main part of this document presents the proposed architecture for the development of the next generation e-VLBI system. This design was created for the purpose of the EXPReS project [12], partially funded by the European Commission (FP6 – IST).
10
Wszechświat na falach radiowych
Kus A.
Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne
|
2005
|
nr 6
204-209
PL
Przedstawiono historię rozwoju i największe osiągnięcia badań radioastronomicznych. Dużą uwagę poświęcono rozwojowi radioastronomii w Polsce, ze szczególnym podkreśleniem osiągnięć Toruńskiego Centrum Astronomii UMK. Centrum posiada 32 m radioteleskop, zaprojektowany i zbudowany całkowicie w Polsce. Instrument ten został szczegółowo opisany, a wyniki badań zaprezentowane w skrócie. Ciągły rozwój bazy aparaturowej dzięki wyjątkowo dobrze rozwiniętej współpracy międzynarodowej tworzy warunki prowadzenia badań nie ustępujące poziomem najlepszym europejskim obserwatoriom.
EN
In this paper a review on history of the development as well as the greatest achievements of Radio Astronomy have been given. On the ground of overall world activity in the field, the Polish contribution is emphasized. Current involvement of Polish Institutes into international research in Radio Astronomy is presented here mostly from the perspective of the Torun Centre for Astronomy (TCfA), which operates large 32 m diameter radio telescope. The telescope designed and built in Poland is one of the best of its class in the world. It is intensively used for VLBI, pulsar and spectral research. Continuous technical development of the telescope instrumentation, conducted in close cooperation with European observatories, and the scientific results obtained in various research programs, places TCfA among top European Radio Observatories.
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