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Time-Periodic Solutions to the Navier-Stokes Equations
No full textThe three-dimensional Navier-Stokes system in the whole space with time-periodic data is investigated. Both the case of a vanishing
and that of a non-vanishing velocity field at spatial infinity are treated. In the first part of the thesis, a maximal regularity framework for the linearized system is developed in a general L^q-setting. A function space with the property that the corresponding linear operator maps this space homeomorphically onto L^q is identified.
Existence of a strong solution herein is then shown for sufficiently "small" data. Moreover, regularity and uniqueness properties
are established. In the following part, an asymptotic expansion at spatial infinity of the strong solution is carried out. In particular,
the asymptotic profile is completely identified. In the final part, existence of a weak solution is proved without any restriction on the
"size" of the data. Furthermore, a decomposition of the weak solution into a time-independent part and a time-periodic part with
finite kinetic energy is obtained. On the basis of this decomposition, regularity properties of the weak solution are derived
Time-Periodic Solutions to the Navier-Stokes Equations
No full textThe three-dimensional Navier-Stokes system in the whole space with time-periodic data is investigated. Both the case of a vanishing
and that of a non-vanishing velocity field at spatial infinity are treated. In the first part of the thesis, a maximal regularity framework for the linearized system is developed in a general L^q-setting. A function space with the property that the corresponding linear operator maps this space homeomorphically onto L^q is identified.
Existence of a strong solution herein is then shown for sufficiently "small" data. Moreover, regularity and uniqueness properties
are established. In the following part, an asymptotic expansion at spatial infinity of the strong solution is carried out. In particular,
the asymptotic profile is completely identified. In the final part, existence of a weak solution is proved without any restriction on the
"size" of the data. Furthermore, a decomposition of the weak solution into a time-independent part and a time-periodic part with
finite kinetic energy is obtained. On the basis of this decomposition, regularity properties of the weak solution are derived
Existence of travelling wave solutions for the heat equation in infinite cylinders with a nonlinear boundary condition
No full textTravelling wave solutions of the heat equation in an unbounded cylinder with a non-linear boundary condition
No full textLet be a bounded domain in . The existence of travelling wave solutions for the heat equation in the unbounded cylinder subject to the nonlinear boundary condition is investigated. Finding such a solution amounts to solving the elliptic PDE for with on . The main result is the existence of a non-trivial solution of this equation for a large class of non-linearities . Additionally, asymptotic behavior at and regularity properties are established. A variational approach is used. More specifically, a weak solution is found as the minimizer of a constrained minimization problem posed in a weighted Sobolev space. Due to underlying domain being unbounded, this problem suffers from a lack of compactness. The problem is solved using a suitable approximation
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
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