1,720,965 research outputs found
Nonsmooth Analysis of Doubly Nonlinear Second-Order Evolution Equations with Non-Convex Energy Functionals
Full text linkWe investigate the existence of strong solutions to a general class of doubly multivalued and nonlinear evolution equations of second order. The multivalued operators are generated by the subdifferential of nonsmooth potentials that live in different spaces, and , where in general and . The proof is based on the regularization of the dissipation potential using the generalized Moreau--Yosida regularization and a semi-implicit time-discretization scheme, which demonstrates the existence of strong solutions to the regularized problem. The existence of solutions to the original problem is then shown by letting the regularization parameter converge to zero. Furthermore, we establish an energy-dissipation inequality for the solution. We conclude with applications of this abstract theory
Zur nichtglatten Analyse von doppelt nichtlinearen Evolutionsinklusionen erster und zweiter Ordnung mit Anwendungen
No full textMany phenomena in nature are characterized by discontinuous processes. To describe them by suitable mathematical models is often a challenge. Evolution inclusions can be a suitable means to model such discontinuous processes mathematically. The present work is devoted to the nonsmooth analysis of doubly nonlinear evolution inclusions of first and second order with leading subdifferential operators and nonmonotone and non-variational perturbations using methods from the theory of convex analysis. The thesis is divided into two parts. In the first part, we prove the existence of strong solutions to abstract Cauchy problems for perturbed generalized gradient flows for a certain class of nonlinear and monotone subdifferential operators acting on the time derivative of the solution, and nonlinear and non-monotone subdifferential operators acting on the solution as well as a certain class of perturbations. As an application of the abstract existence result, we show the existence of weak solutions of an initial-boundary value problem. In the second part, we prove the existence of strong solutions to abstract Cauchy problems for doubly nonlinear evolution inclusions of second order. In doing so, we treat the equations with linear and nonlinear damping separately. In the case of linear damping, we consider a special class of leading linear potential operators acting on the time derivative of the solution, and nonlinear subdifferential operators acting on the solution. In the case of nonlinear damping, we consider the reverse case. In both cases, we allow a perturbation which depends nonlinearly on the solution as well as its time derivative. As an application of the abstract existence results, we prove the existence of weak solutions to certain initial-boundary value problems.Viele Phänomene in der Natur sind durch unstetige Prozesse charakterisiert. Diese durch ein geeignetes mathematisches Modell zu beschreiben, stellt oftmals eine Herausforderung dar. Evolutionsinklusionen können ein geeignetes Mittel sein, solche unstetigen Prozesse mathematisch zu modellieren. Die vorliegende Arbeit widmet sich der nichtglatten Analyse von doppelt nichtlinearen Evolutionsinklusionen erster und zweiter Ordnung mit führenden Subdifferentialoperatoren und nicht-monotonen und nicht-variationellen Störungen mit Methoden aus der Theorie der konvexen Analysis. Die Arbeit ist in zwei Teile gegliedert. Im ersten Teil weisen wir die Existenz von starken Lösungen zu abstrakten Cauchy Problemen für gestörte verallgemeinerte Gradientenflüsse für eine bestimmte Klasse von nichtlinearen und monotonen Subdifferentialoperatoren, welche auf die Zeit- Ableitung der Lösung wirken, und nichtlinearen und nicht-monotonen Subdifferentialoperatoren, welche auf die Lösung wirken, sowie einer bestimmten Klasse von Störungen nach. Als Anwendung des abstrakten Existenzresultats, zeigen wir die Existenz von schwachen Lösungen eines Anfangs-Randwertproblems. Im zweiten Teil weisen wir die Existenz von starken Lösungen zu abstrakten Cauchy Problemen für doppelt nichtlineare Evolutionsinklusionen zweiter Ordnung nach. Dabei behandeln wir hyperbolische Gleichungen mit linearer und nichtlinearer Dämpfung gesondert. Im Fall der linearen Dämpfung betrachten wir eine spezielle Klasse von führenden linearen Potentialoperatoren, welche auf die Zeit-Ableitung der Lösung wirken, und nichtlinearen Potentialoperatoren, welche auf die Lösung wirken. Im Fall der nichtlinearen Dämpfung betrachten wir den umgekehrten Fall. In beiden Fällen erlauben wir eine Störung, welche nichtlinear von der Lösung sowie ihrer Zeit-Ableitung abhängt. Als Anwendung der abstrakten Existenzresultate weisen wir die Existenz von schwachen Lösungen zu gewissen Anfangs-Randwertproblemen nach
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
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