1,721,033 research outputs found
Design and characterization of resonant devices for optical applications
Full text linkPeriodic structures have attracted huge research interest over the past many years due to their interesting electromagnetic properties. There are lots of useful applications in the fields of photonics and microwave engineering that come from periodic structures. Examples of periodic structures include diffraction gratings, photonic crystals, phased array antennas, frequency selective surfaces, and metamaterials. A diffraction grating is composed of diffracting elements arranged periodically. The spacing between these elements is comparable to the wavelength of the incident light. The amplitude, or phase, or both, of the diffracted electromagnetic radiation from a diffraction grating, can be modified in a controlled and predictable manner. Another interesting phenomenon is the presence of sharp resonant features in the optical spectra of the gratings such as Guided-Mode Resonances (GMR). GMR gratings have been employed in wide-ranging applications such as sensors for biosensing, optical absorbers, efficient photodetectors and tunable filters for optical communication systems, reflection mirrors for lasers, and spectrometers.
The first part of this work focuses on the design, fabrication, and characterization of resonant pillar gratings. This is further split into two parts. The first part describes the graphene-based pillar grating for optical absorber applications. The performance of the proposed periodic structure is investigated through numerical simulations. The proposed design exploits the guided mode resonances of the structure to achieve enhanced absorption in the monolayer graphene. In the second part, a phase change material vanadium-dioxide (VO2) is integrated with the pillar grating structure to achieve the thermal tuning of the optical response exploiting the phase change properties of VO2. The grating has been fabricated utilizing a nanoimprint lithography system exploiting a silicon mold. VO2 nano-powders have been deposited by spin-coating. In addition to the experimental tests, the proposed structure is simulated using the RCWA method. Next, plasmonic grating structures on planar as well curved surfaces are designed and analyzed through numerical simulations for sensing and Surface Enhanced Raman Spectroscopy (SERS) applications. The work related to plasmonic structures has also been further split into two parts. In the first part, a planar plasmonic grating is designed and synthesized for sensing applications in the transmission domain exploiting Extraordinary Transmittance (EOT) properties of the plasmonic modes as well as the sensitivity of these modes to the changes in the refractive index of the surrounding media. A Finite Difference Time Domain (FDTD) model of the finite set of nanoplatelets has been developed to theoretically investigate and optimize the nanostructure as well as validate the experimental results. Plasmonic modes can concentrate light to much smaller locations creating field hotspots. This makes plasmonic structures a suitable platform for SERS. In the second part of the work, plasmonic gratings on planar and curved surfaces are investigated as SERS platforms
Degree Variance And Emotional Strategies Catalyze Cooperation In Dynamic Signed Networks
Full text linkWe study the problem of the emergence of cooperation in dynamic signed networks where agent strategies coevolve with relational signs and network topology. Running simulations based on an agent-based model, we compare results obtained in a regular lattice initialization with those obtained on a comparable random network initialization. We show that the increased degree heterogeneity at the outset enlarges the parametric conditions in which cooperation survives in the long run. Furthermore, we show how the presence of sign-dependent emotional strategies catalyze the evolution of cooperation with both network topology initializations. Proceedings 28th European Conference on Modelling and Simulation © ECMS Flaminio Squazzoni, Fabio Baronio, Claudia Archetti, Marco Castellani (Editors)
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
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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