1,721,243 research outputs found
A new model of geometric chirality for two-dimensional continuous media and planar meta-materials
No full textWe have, for the first time, identified ten tenets of two-dimensional (2D) chirality that define and encapsulate the symmetry and scaling behaviour of planar objects and have used them to develop three new measures of geometric 2D chirality. All three models are based on the principle of overlap integrals and can be expressed as simple analytical functions of the two-dimensional surface density, rho(r). In this paper we will compare the predicted behaviour of these models and show that two of them are fully integrable and scalable and can therefore be applied to both discrete and continuous 2D systems of any finite size, or any degree of complexity. The only significant difference in these two models appears in their behaviour at infinite length scales. Such differences could, however, have profound implications for the analysis of chirality in new generations of planar meta-materials, such as chiral arrays, fractals, quasi-periodic 2D crystals and Penrose tiled structures
Giant optical activity in dielectric planar metamaterials with 2D chirality
No full textFor the first time, all-dielectric planar chiral metamaterials consisting of arrays of silicon nitride gammadions on fused silica substrates have been fabricated, and shown to be capable of inducing large changes to the polarization states of transmitted light in a manner that is dependent on the two-dimensional chirality of the microstructured silicon nitride film. The polarization response is found to reverse for opposite enantiomers, and also for the same enantiomer when it is illuminated from opposite sides of the structure. In addition, the polarization states of the various diffracted beams are found to be non-reversible. These structures therefore appear to display elements of non-reciprocal behaviour. The polarization responses of complementary designs, different chiral geometries and various silicon nitride film thicknesses have also been studied. As a result we conclude that multiple reflections within the patterned silicon nitride layer play an important role in defining the mechanism by which these structures are able to modify the polarization states of diffracted light
Potts, A C, VX43521
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/411377Surname: POTTS. Given Name(s) or Initials: A C. Military Service Number or Last Known Location: VX43521. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 38172.227088
Item: [2016.0049.43641] "Potts, A C, VX43521
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
Potts, A J W, NX31152
No full textThis record was harvested from a previous catalogue system and will be withdrawn in 2025. Information in this record may be superseded or incomplete. Visit this record in UMA's new catalogue at: https://archives.library.unimelb.edu.au/nodes/view/411375Surname: POTTS. Given Name(s) or Initials: A J W. Military Service Number or Last Known Location: NX31152. Missing, Wounded and Prisoner of War Enquiry Card Index Number: 21120.227086
Item: [2016.0049.43639] "Potts, A J W, NX31152
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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