1,720,960 research outputs found
Machine learning for the free-form inverse design of metamaterials
No full textWe present our work on using deep neural networks for the prediction of the optical properties of nanophotonic structures and for the inverse design of such nanostructures. First we show that neural networks can indeed be used to predict the optical properties of nanostructured materials such as metasurfaces. Subsequently, we show that it is possible to perform the inverse design of metasurfaces given a set of desired optical properties. This was achieved through the careful design of the neural networks and the creation of training data which were labelled with the respective optical properties and the degree to which it is possible to manufacture these nanophotonic structures. Furthermore, a CGAN network with 5 neural networks working together was developed to overcome problems with the non-uniqueness of designs, to prevent mode collapse, and to increase the experimental feasibility of the generated structures
Machine learning for the free-form inverse design in nanophotonics
No full textIn the fast developing field of nanotechnology, nanophotonics has emerged as a revolutionary technology, controlling the complex interplay between light and matter at the nanoscale. Crucial to the advancement of this field is the ability to manipulate the propagation of electromagnetic waves by shaping the transmitted or reflected wavefront through the design of structures that are only a fraction of the wavelength in size. The design of these subwavelength structures forming a quasicontinuous material is complex and usually exceeds human intuition. In this thesis, we present our approach utilizing deep neural networks for both the prediction of optical properties of nanostructures and their inverse design. First, we demonstrate the feasibility of employing neural networks to accurately predict the optical properties of nanostructured materials, with a particular emphasis on metasurfaces. Given the increasing need for miniaturization together with smaller optical losses, the emergence of metasurfaces---single layers of phase-modifying nanostructures---has heralded a significant advancement, enabling unprecedented manipulation of light beyond the capabilities of traditional materials. Subsequently, we present methodologies to achieve inverse design of metasurfaces, guided by specific desired optical attributes and fabrication constraints. This is achieved through neural network design and the generation of training data, labeled with corresponding optical characteristics and manufacturability constraints. We implemented a conditional generative adversarial network comprised of five synergistic neural networks. This approach effectively mitigates challenges related to design non-uniqueness, mode collapse, and experimental feasibility. Additionally, our research explores various techniques to optimize and stabilize neural network training and introduces novel network graph compositions, contributing to a versatile generator model capable of conceiving multiple metasurface unit cells with predefined, interconnected properties. This thesis thus provides insights and methodologies for inverse design, contributing to the continued evolution of nanophotonic design and applications
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Get PDFWe 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
Get PDFWe 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
Deep Neural Networks for the Prediction of the Optical Properties and the Design of Metamaterials
No full textWe will present our work on using deep neural networks for the prediction of the optical properties of free-form nanophotonic structures and for their inverse design. We designed neural networks and created training data, which were labelled with the respective optical properties and the degree of manufacturability. Furthermore, a cGAN network with 5 neural networks was developed to overcome problems with non-uniqueness and mode collapse, and to increase the experimental feasibility of the generated structures
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
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