64 research outputs found

    The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases

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    The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article

    Evaluation of Ionospheric HF MIMO Channels: two complementary circular polarizations reduce correlation.

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    International audienceAn original mul tiple-input, multiple-output (MIMO) system for a transhorizon transmission through the ionospheric channel is presented. This project, involving decametric wavelengths, has to cope with the constraints of reasonable array dimensions at both ends of the radio link. Therefore, this work considers a diversity in transmitted polarizations as an alternative to the classical spatial diversity and, more specifically, the generation of complementary circular polarizations. The design of the corresponding system is described with a focus on antenna arrays, waveforms, and signal processing for channel sounding. This novel communication system has been tested on a 850-km long radio link to exhibit the degree of diversity provided by the ionospheric MIMO channel. The measurements indicate a significantly low level of correlation for the four-channel transfer functions linking the transmitting and receiving ends (in a frequency dispersive context). Moreover, the ergodic or outage capacities have been calculated over several hundreds of channel estimations: the gain in the capacity of a MIMO versus a single-input, single-output (SISO) architecture reaches the value of 1.82

    Implementation of a MIMO solution for ionospheric HF (3-30 MHz) radio links

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    International audienceMIMO architectures are generally based on antenna arrays with spatial diversity. An implementation in the particular context of trans horizon transmission through the ionospheric channel copes with the problem of prohibitive array aperture, the wavelength being decametric in the corresponding HF frequency band (3-30 MHz). Therefore, this paper proposes an alternative resorting to the diversity in transmitted polarizations. The design of an original 2x2 MIMO system is detailed and the experimentations carried out on a 280km long transmission are presented. The first results underline a data transfer rate reaching a value of 24.09 kbps (in a 4.2 kHz bandwidth) which significantly exceeds the current standards for HF modems. Keyword

    Development and test of a trans-horizon communication system based on a MIMO architecture

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    International audienceA multiple-input multiple-output (MIMO) system for trans-horizon radio communications within the high-frequency (HF) band (3 to 30 MHz) is presented. The diversity of transmitted polarizations is proposed as an alternative to spatial diversity in order to limit the aperture of antenna arrays at both ends of the radio link. In a theoretical step providing the estimation of capacity gain for different MIMO architectures, a 2 x 2 MIMO solution transmitting two complementary circular polarizations is identified as a balanced trade-off between performance increase and complexity. The design of the corresponding system is described with a focus on antenna arrays and the kind of signal processing that should be implemented. This novel communication system has been tested on a 280-km-long radio link. The first results underline a data transfer rate reaching a value of 24.09 kbps (in a 4.2-kHz bandwidth) that significantly exceeds the current standards for HF modems
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