1,721,004 research outputs found
Scattering from an electric–magnetic anisotropic rough interface
No full textScattering from a rough interface between a simple isotropic medium and a uniaxial lossy medium is analyzed using the first-order perturbation theory (PT) and the small slope approximation (SSA). We consider a more generic uniaxial lossy medium exhibiting electric and magnetic anisotropy and an arbitrarily oriented optic axis. Scattering from the rough interface of such a medium is analyzed by assuming both deterministic sinusoidal function and a Gaussian distribution for the surface roughness. We also study the coherent and incoherent intensities employing both the PT and the SSA. The impact of surface roughness, anisotropy and material losses on scattering characteristics is examined. We show that the parameters describing the surface roughness, i.e., height, period, and slope may add significant contribution to the electromagnetic scattering from the anisotropic interface
Scattering by a Circular Cylinder Buried Under a Slightly Rough Surface: The Cylindrical Wave Approach
No full text""\\"An analytical-numerical technique for the scattering. problem of a plane wave by a cylinder buried under a rough. surface, based on the Cylindrical Wave Approach, is presented.. The rough deviations on the interface are dealt with by means. of the Small Perturbation Method. Reflection and transmission. coefficients are evaluated in a first order approximation, and fields. are the sum of a zeroth-order solution, relevant to flat surface,. and first-order perturbation fields, associated to the surface. roughnesses. Numerical results are obtained through an exact. evaluation of the spectral integrals, giving results both in nearand. far-field regions, for the case of an interface with sinusoidal. profile. The approach is validated through comparisons with. the literature, and results showing the effect of geometrical and. physical parameters on the scattered field are reported.\\""
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Jonathan Charles Paramore Collection
No full textThis is an elicitation of words read within a three-sentence frame for the purpose of acoustic analysis of word- and phrase-level stress correlates
Spectral-domain solution to the electromagnetic scattering of a two-dimensional beam by cylinders buried below a flat interface
No full textAn analytical-numerical approach in the spectral domain is developed for the scattering problem by buried objects excited by a two-dimensional illumination field. The scatterers are perfectly conducting cylinders, which are placed in a semi-infinite medium below a flat interface. The source field is described by an arbitrary illumination function, and it is represented by means of its plane-wave spectrum. The cylindrical-wave approach is applied to represent the fields scattered by the cylinders. All the field contributions are expressed through spectral integrals, which allow to evaluate their interaction with the interface in terms of a superposition of monochromatic plane waves. Such integrals are evaluated in an accurate way, which can lead to results both in near-field and far-field regions. In this paper, the general theoretical approach is described, and numerical results are given for the case of an incident Gaussian beam. Two-dimensional field maps in both the air and lower regions are reported in the case of one and two scatterers. An application of the technique to the diagnostic of reinforced concrete is reported, showing the use of the radar scattering cross-section ratio to determine the size of rebar diameters. Modelling results validate the assumption proposed by other authors that the radar scattering cross-section ratio can be used to determine rebar diameters using the monotonic behaviour observed at lower frequencies
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
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Jonathan Charles Paramore Collection
No full textThis is an elicitation of words read within a three-sentence frame for the purpose of acoustic analysis of word- and phrase-level stress correlates
Variations on the Author
No full text“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
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
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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