1,720,981 research outputs found
Reliable approximation of the solution of time-harmonic electromagnetic boundary value problems involving bianisotropic media for numerical simulator testing
No full textDifficulties in recognizing ill-posed electromagnetic problems involving wrong effective models of media
No full textThe set of ill-posed time-harmonic electromagnetic
boundary value problems is shown to be much richer than expected
so far, when all fine details of composite media are neglected
and effective media, possibly anisotropic, are considered. This
result seems to suggest that it can be extremely difficult to identify
wrong formulations of electromagnetic boundary value problems
also because, unfortunately, numerical simulations with common
discretizations could give no help in recognizing them
Simple waveguide junctions whose straightforward modelling leads to unsolvable boundary value problems
No full text
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
Psychometric properties of the Rivermead Mobility Index in Italian stroke rehabilitation inpatients
No full textObjective: To examine the internal consistency, validity, responsiveness and test scalability of the Rivermead Mobility Index (RMI) in Italian rehabilitation inpatients recovering from stroke. Design: Seventy-three stroke inpatients undergoing rehabilitation were assessed at admission (T0) and five weeks later (T1), using RMI, the motor (motFIM) and cognitive (cognFIM) subscales of the Functional Independence Measure, the 'leg' section of the Motricity Index and Trunk Control Test. Results: Cronbach's alpha of the RMI was 0.92. The item-to-total correlation coefficients (rrb) ranged from 0.36 to 0.83, all p < 0.003. All correlations between RMI scores and the other instruments, both at T0 and T1, were statistically significant (r ≥ 0.49, all p < 0.0001), except those with cognFIM. The difference in RMI scores over the testing period was statistically significant (sign test: z = 7.1, p < 0.0001) and the effect size was 0.89. The coefficient of reproducibility was 0.95 at T0 and 0.93 at T1, and both coefficients of scalability were 0.67. Conclusions: The study confirms the internal consistency, construct validity and responsiveness of the RMI, according to the classic psychometric indexes. However, some minor concerns arise regarding: (a) a floor effect of RMI in subacute rehabilitation stroke inpatients at admission and; (b) one item ('bathing') that seems sensitive to cultural and environmental factors. Moreover, even though RMI met the scaling criteria, the item hierarchy is not coincident with the one originally postulated. So, RMI should be considered only as a summated index with ordinal properties, and not a hierarchically ranked scale
An Enhanced Serial Network Spectrum Sensing Scheme for Multiple Antenna Cognitive Radios
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