1,721,644 research outputs found
Replication Data for Divergent hydrological responses to variation in climate and watershed characteristics
No full textThe dataset contains average annual precipitation, runoff, potential evapotranspiration of 537 watersheds over the period 1948-1975, 1976-2003, and 1948-2003
Replication Data for Divergent hydrological responses to variation in climate and watershed characteristics
No full textThe dataset contains average annual precipitation, runoff, potential evapotranspiration of 537 watersheds over the period 1948-1975, 1976-2003, and 1948-2003
A relaxed coupling method for algebraically constrained mechanical systems
Full text linkA coupling method is presented that aims at computing the dynamics of constrained mechanical systems connected by algebraic constraints. A relaxed coupling method is proposed, where each subsystem is reformulated as a set of ODEs and solved with an iteration process. The method is straightforward to implement, also for parallelization. The core idea is to eliminate the Lagrange multipliers of the DAEs that describe the constraint dynamics of each subsystem using a proper constraint stabilization technique. A linear combination of the constraint equations at position and velocity level is enforced, to prevent the occurrence of numerical drifting. The associated stabilization parameter is chosen in relation to the time step size. The effectiveness of the proposed approach is verified by solving a three-dimensional problem with rigid and flexible bodies. The results show that the method is effective in co-simulating algebraically constrained mechanical systems
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
Efficient explicit integration for dynamics of inextensible ANCF beams with large deformations
No full textExplicit integration in flexible multibody dynamics is highly attractive for real-time simulation but poses significant efficiency challenges. The bending and axial straining dynamics of slender structural components, such as beams and cables, operate on different time scales. As a result, axial straining—usually the higher-frequency one, though often of minor interest—imposes strict time step limitations for algorithmic stability in explicit integration schemes. This work achieves efficient explicit integration for inextensible flexible beams undergoing large deformations. The key is to develop a dynamic model optimized for explicit integrators by reducing the stiffness of the problem. To this end, an absolute nodal coordinate formulation for inextensible beams is proposed, where the elastic potential energy is derived from the direct multiplication of the first and second derivatives of the position vector with respect to the arc-length coordinate. This formulation results in equations of motion with moderate stiffness, making it well-suited for explicit schemes. Inextensibility is rigorously enforced through algebraic constraints on slope vector lengths, applied either at discrete points or via a fixed-length constraint on the entire span of the beam. A constraint stabilization technique is employed to transform the resulting system of differential-algebraic equations into a set of ordinary differential equations, ensuring numerical stability. The main advantage of this method is its ability to accommodate large time steps, significantly improving computational efficiency. This capability makes explicit simulation schemes more practical and contributes to enabling real-time simulation of mechanical systems with flexible beams or cables
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
A projection continuation approach for minimal coordinate set constrained dynamics
Full text linkThe formulation of constrained system dynamics using coordinate projection onto a subspace locally tangent to the constraint manifold is revisited using the QR factorization of the constraint Jacobian matrix to extract a suitable subspace and integrating the evolution of the QR factorization along with that of the constraint Jacobian matrix, as the solution evolves. A true continuation algorithm is thus proposed to track the evolution of the subspace of independent coordinates. It does not visibly affect the quality of the solution but avoids the artificial algorithmic irregularities or discontinuities in the generalized velocities that could otherwise result from arbitrary reparameterizations of the coordinate set. The characteristics of the proposed subspace evolution approach are exemplified by solving simple single- and multi-degree-of-freedom problems
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
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