1,721,098 research outputs found
Revisiting nonlinear interactions between signal and noise in presence of FEC
No full textWe review the system implications of the nonlinear interactions between signal and noise in 10Gb/s OOK-NRZ long-haul systems working at low signal-to-noise ratios and emploting FECs
Parametric gain impairments in 10 Gb/s coded optical systems working at low signal-to-noise ratios
No full textWe show that parametric gain may force the use of more powerful forward error correction codes than
planned when ignoring such effect in 10 Gb/s dispersion-managed transmission systems
Valutazione esatta del BER per DPSK e OOK e confronto con l'approssimazione gaussiana in sistemi terrestri a 40 Gb/s
No full textRevisiting Binary Sequence Length Requirements to Accurately Emulate Optical Transmission Systems in Highly Dispersive Regime
No full textWhen increasing channel bit rate beyond 10Gb/s or when operating over fiber lines with sparse or no in-line dispersion
compensation, Kerr-like non-linear effects can be considered as second order with respect to dispersive effects, because
pulse broadening can expand over numerous neighbor pulses, before optical non-linear effects imprint their signature
noticeably. To accurately emulate the interactions between pulses in this case, a few studies emphasized that Pseudo-
Random Binary Sequences (PRBS) should be used, with exponential dependence of the required PRBS length on bit rate
and accumulated dispersion. In this paper, we explain our strategy to numerically estimate the required number of
random, noisy bits for Monte-Carlo simulations, and show that it weakly increases in presence of pulse to pulse
correlations and commonly tolerated levels of non-linearities (i.e. leading to transmission penalties as high as 1.5dB, for
reference BERs of 10-2, 10-3 or 10-5) . Then we determine the actual required PRBS length that yields the same
(sufficient) BER accuracy as the MC method. We demonstrate its actual dependence on BER, and show that MC theory
provides a reliable upper bound in FEC-assisted, highly dispersive systems
Implications of nonlinear interaction of signal and noise in low-OSNR transmission systems with FEC
No full textWe review the performance degradation due to noise parametric gain in long-haul
single-channel NRZ terrestrial systems working at low OSNR and its implications on system
design in the presence of forward error correction
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe 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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