1,720,958 research outputs found
Determining Elastic Constants of Nematic Liquid Crystals Using Neural Networks
No full textTri elastične konstante, ki pripadajo trem osnovnim deformacijam orientacijske ureditve molekul nematskega tekočega kristala (pahljačasti, zvojni in upogibni), določajo ravnovesno ureditev in relaksacijsko dinamiko iz neravnovesnega stanja. V
magistrskem delu razvijemo novo metodo določanja elastičnih konstant nematskih tekočih kristalov na osnovi kombinacije mezoskopskega numeričnega modeliranja in strojnega učenja nevronskih mrež. Elastične konstante določimo tako, da približno
10⁵-krat z minimizacijo Frank-Oseenove elastične proste energije simuliramo relaksacijo tekočega kristala z naključnimi elastičnimi konstantami iz poljubne začetne konfiguracije direktorja v ravnovesno stanje. Hkrati z uporabo Jonesovega matričnega formalizma izračunavamo intenziteto skozi vzorec prepuščene monokromatske svetlobe. Tako dobljene časovne odvisnosti intenzitete in pripadajoče elastične konstante uporabimo kot učno množico za učenje nevronske mreže, s katero aproksimiramo netrivialno funkcijo, ki iz časovne odvisnosti intenzitete svetlobe napoveduje elastične konstante. V magistrskem delu pokažemo, katere od konstant lahko določimo v značilnih tipih tekočekristalnih celic. Predstavimo še, kako nevronsko mrežo, naučeno s podatki, ki so pridobljeni z numeričnimi simulacijami, lahko uporabimo tudi za napovedovanje elastičnih konstant iz eksperimentalno izmerjenih podatkov. Naše delo prispeva k razvoju uporabe metod strojnega učenja v fiziki mehkih snovi kot novemu močnemu metodološkemu pristopu, posebej v povezavi med modeliranjem in eksperimenti.In a nematic liquid crystal, three elastic constants related to three deformation modes of the orientational order (splay, twist and bend) govern the orientational configuration in the equilibrium, as well as the leading relaxational dynamics. In this MSc thesis, a new method for determining elastic constants of nematic liquid crystals is developed based on the combination of mesoscopic continuum modelling and neural networks. First, the relaxation from a random initial state of the nematic liquid crystal to the minimum free energy state is numerically simulated 10⁵ times, using Frank-Oseen free energy minimisation for random values of elastic constants. Simultaneously, the transmittance of the nematic sample for monochromatic polarized light is calculated using the Jones matrix formalism. The obtained time-dependent light transmittances and the corresponding elastic constants form a training data set, based on which a neural network is trained, aiming to approximate a nontrivial function that predicts the unknown elastic constants from the time dependence of the intensity of the transmitted light. This allows us to show which elastic constants can be determined in different types of liquid crystal cells and nematic geometries. In addition, we demonstrate that the neural network, which is originally trained on numerically obtained data, can also be used to determine elastic constants from experimentally measured data. Overall, this work contributes towards the development of machine learning methods in the field of general soft matter, as the new strong methodological tools, allowing us to combine theoretical modelling and experimental approaches
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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