121,796 research outputs found
L'enfant trouvé sous la toise
No full textColavolpe Isabelle. L'enfant trouvé sous la toise. In: Histoire, économie et société, 1987, 6ᵉ année, n°3. L'enfant abandonné. pp. 409-420
Reduced complexity FDM-CPM dectector with multiple access interference cancellation
No full textInternational patent, International patent application n. PCT/EP2010/059144, June 2010, International Publication n. WO/2010/149791, December 2010
The capacity of the noncoherent channel
No full textThe capacity of a random-phase additive white Gaussian noise (AWGN) channel, referred to as noncoherent
channel, is investigated in the case of a transmission of N information symbols. The non-Gaussianity of the
capacity-achieving distribution is shown and a lower bound on the channel capacity is derived. For increasing values
of the number of transmitted symbols N, the capacity of a noncoherent channel is shown to asymptotically approach
that of a coherent channel, i.e., a known-phase AWGN channel. The asymptotical Gaussianity of the capacity-achieving
distribution is also shown. Based on the derived lower bound, the inherent capacity loss of a noncoherent channel, as
compared to a coherent one, may be considered very limited for all but very small values of N. This result may be viewed
as the information theoretic counterpart of a similar conclusion derived by many authors with reference to the probability
of detection error
Variable Data Rate Architectures in Optical LEO Direct-to-Earth Links: Design Aspects and System Analysis
No full textIn the frame of ongoing efforts between space agencies to define an on-off-keying-based optical low-Earth-orbit (LEO) direct-to-Earth (DTE) waveform, this paper offers an in-depth analysis of the Variable Data Rate (VDR) technique. VDR, in contrast to the currently adopted Constant Data Rate (CDR) approach, enables the optimization of the average throughput during a LEO pass over the optical ground station (OGS). The analysis addresses both critical link level aspects, such as receiver (time, frame, and amplitude) synchronization, as well as demonstrates the benefits stemming from employing VDR at system level
Bayesian and non-Bayesian methods for joint decoding and detection in the presence of phase noise
No full textHow to significantly improve the spectral efficiency of linear modulations through time-frequency packing and advanced processing
No full textAbstract—We recently investigated the spectral efficiency, achievable with a symbol-by-symbol receiver, for linear modula-tions employing time-frequency packing. In this paper, we will investigate the improvements that can be obtained by increasing the receiver complexity. In the numerical results, we will mainly concentrate on time packing (an extension of the so called faster-than-Nyquist signaling technique) and on (i) receivers based on linear processing plus symbol-by-symbol detection or (ii) receivers based on a more sophisticated trellis processing with constrained complexity. Finally, the potential advantage of the proposed signalling scheme when combined with conventional low-density parity-check (LDPC) coding of the DVB-S2 air interface will be presented. I
On linear predictive receivers for fading channels
No full textThe authors discuss maximum likelihood sequence detection (MLSD) based on prediction techniques for linearly modulated digital signals transmitted over fading channels. Efficient implementations of the sequence detector are investigated and a general formulation for computing the prediction coefficients is derived. Furthermore, the equivalence of different existing prediction-based receivers is shown
Improving the spectral efficiency of nonlinear satellite systems through timefrequency packing and advanced processing
No full texta
A Multi-Language Comparison of Influences on Author Verification using Character N-Grams
No full textWe create a new multi-language corpus for author verification based on Wikipedia talkpages, and evaluate the influence that differences in topic and time have on character n-gram author profiles. Topic alignment between two texts is found to increase author verification precision, and an authors writing style is found to change over time, but not more significantly after 3 years than after 1 year.Information ArchitectureWISElectrical Engineering, Mathematics and Computer Scienc
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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