1,720,958 research outputs found
Stability properties of stochastic maximal Lp-regularity
No full textIn this paper we consider Lp-regularity estimates for solutions to stochastic evolution equations, which is called stochastic maximal Lp-regularity. Our aim is to find a theory which is analogously to Dore’s theory for deterministic evolution equations. He has shown that maximal Lp-regularity is independent of the length of the time interval, implies analyticity and exponential stability of the semigroup, is stable under perturbation and many more properties. We show that the stochastic versions of these results hold
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
Het inverteerbaar maken van matrices (Restricted Invertibility)
No full textMatrices zijn objecten die vrij centraal staan in de studie der wiskunde. Ze worden gebruikt om data te representeren, zoals grafen en stelsels van lineaire vergelijkingen. Soms kan het handig zijn om zo'n willekeurige matrix te kunnen benaderen met een 'schaarse' of 'gestructureerde' matrix. Nadruk ligt hierbij op het feit dat de benadering zinvol moet zijn en er dus extra eisen aan deze benadering worden gesteld. De meest zinvolle benadering hiervoor is in 2010 gegeven door Daniel Spielman en Nikhil Srivastava, onder andere toegepast op grafen. In grafentheorie komt dit resultaat min of meer overeen met het Er wordt uitgelegd hoe Spielman en Srivastava een zinvolle benadering van zo'n matrix vonden. Daarnaast wordt er een computeralgortime gepresenteerd die als output die zinvolle matrix heeft. Als laatste wordt dit algoritme toegepast op een aantal matrices ter demonstratie.Applied mathematicsElectrical Engineering, Mathematics and Computer Scienc
Correlation inequalities and applications to vector-valued Gaussian random variables and fractional Brownian motion
Full text linkElectrical Engineering, Mathematics and Computer Scienc
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
R-boundedness of smooth operator-valued functions
No full textIn this paper we study -boundedness of operator families \mathcal{T}\subset \calL(X,Y), where and are Banach spaces. Under cotype and type assumptions on and we give sufficient conditions for -boundedness. In the first part we show that certain integral operator are -bounded. This will be used to obtain -boundedness in the case that is the range of an operator-valued function T:\R^d\to \calL(X,Y) which is in a certain Besov space B^{d/r}_{r,1}(\R^d;\calL(X,Y)). The results will be applied to obtain -boundedness of semigroups and evolution families, and to obtain sufficient conditions for existence of solutions for stochastic Cauchy problems.Electrical Engineering, Mathematics and Computer Scienc
Some remarks on tangent martingale difference sequences in L1-spaces
No full textDelft Institute of Applied MathematicsElectrical Engineering, Mathematics and Computer Scienc
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
On Besov regularity of Brownian motions in infinite dimensions
No full textElectrical Engineering, Mathematics and Computer Scienc
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