1,738,136 research outputs found
A perturbation approach for the Schrödinger-Born-Infeld system: Solutions in the subcritical and critical case
No full textIn this paper, we study the following Schrödinger-Born-Infeld system with a general nonlinearity {−Δu+u+φu=f(u)+μ|u|4uinR3,−div([Formula presented])=u2inR3,u(x)→0,φ(x)→0,asx→∞, where μ≥0 and f∈C(R,R) satisfies suitable assumptions. This system arises from a suitable coupling of the nonlinear Schrödinger equation and the Born-Infeld theory. We use a new perturbation approach to prove the existence and multiplicity of nontrivial solutions of the above system in the subcritical and critical case. We emphasise that our results cover the case f(u)=|u|p−1u for p∈(2,5/2] and μ=0 which was left in [2] as an open problem
Assessing the TOPKAPI non-linear reservoir cascade approximation by means of a characteristic lines solution
No full textTOPKAPI is a physically based distributed rainfall-runoff model derived upon the assumption that the horizontal flow at a point in the soil, over the slopes and in the channel network can be approximated by means of a kinematic wave model. The TOPKAPI model combines this kinematic approach with a digital elevation model (DEM)-based description of a basin. Similarly to what is done in the finite element approach, the basic model equations are derived by integrating in space the point process equations up to a finite dimension, the pixel, thus converting the original kinematic partial differential equations into a cascade of finite dimension non-linear reservoir ordinary differential equations. These new equations are 'structurally similar' for all the processes (flow in the soil, over the slopes and in the channel network) and are shown to be representative of the original equations at the new finite pixel scale. With a view to assessing the quality of the approximation, the paper presents a comparison study in which a quasi-analytical approach based upon the characteristic kinematic wave solution of the original equations is compared to the solution provided by the non-linear reservoir finite scale approximation. The test is first applied to a simplified theoretical case in order to show the quality of the approximation at small scales. Successively it is applied to two real-word cases: the Upper Reno catchment based on 400 x 400 m(2) pixels and the Sieve River catchment using 1 x 1 km(2) pixels. All the results show that the cascade of non-linear reservoirs is a good finite dimension approximation of the subsurface flow in the soil, the flow over the slopes and the flow in the channel network, which allows us to properly retain the physical properties of the original equations at finite scales that range from a few metres up to I k
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
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