1,721,274 research outputs found
Data-Driven Identification of Quadratic Representations for Nonlinear Hamiltonian Systems using Weakly Symplectic Liftings
No full text<p>This repository contains the Python implementation using the PyTorch framework to learn Quadratic Hamiltonian systems.</p>
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
Palindromic Linearization and Numerical Solution of Nonsymmetric Algebraic T-Riccati Equations
Full text linkWe identify a relationship between the solutions of a nonsymmetric algebraic T Riccati equation (T -NARE) and the deflating subspaces of a palindromic matrix pencil, obtained by arranging the coefficients of the T -NARE. The interplay between T NAREs and palindromic pencils allows one to derive both theoretical properties of the solutions of the equation, and new methods for its numerical solution. In particular, we propose methods based on the (palindromic) QZ algorithm and the doubling algorithm, whose effectiveness is demonstrated by several numerical tests
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
M-M.E.S.S.-1.0 - The Matrix Equation Sparse Solver Library
No full textThe M-M.E.S.S. toolbox provides solvers for large-scale, sparse, symmetric linear and quadratic matrix equations. These can be algebraic and differential equations and the solvers are in their core all based on the low-rank ADI method. M-M.E.S.S. can be seen as the successor to the LyaPack toolbox with an improved formulation of the ADI, that now properly supports generalized state space systems, but also special structured DAEs. It features additional solvers for differential equations, improved shift parameter computation and a guarantee to compute real low-rank factorizations, but follows the same general philosophy of user supplied functions that the LyaPack toolbox used.The Software is provided as both a Matlab toolbox file and a zip-archive. The toolbox-file needs a recent Matlab version to install properly. The content of the zip-archive is equipped with all functions to also run on older releases. The software has also sucessfully been tested in octave version 4 and higher. In order to get all functions registered properly, change to the installation folder and run the mess_path function. This will set the searchpath correctly for the current session
M-M.E.S.S. - The Matrix Equation Sparse Solver Library
No full text<p>The M-M.E.S.S. toolbox provides solvers for large-scale, sparse, symmetric linear and quadratic matrix equations. These can be algebraic and differential equations and the solvers are in their core all based on the low-rank ADI method. M-M.E.S.S. can be seen as the successor to the LyaPack toolbox with an improved formulation of the ADI, that now properly supports generalized state space systems, but also special structured DAEs. It features additional solvers for differential equations, improved shift parameter computation and a guarantee to compute real low-rank factorizations, but follows the same general philosophy of user supplied functions that the LyaPack toolbox used.</p>The Software is provided as a Matlab toolbox (mltbx) file, an Octave package (tar.gz) and a zip-archive. The toolbox-file needs a recent Matlab version to install properly. The Octave package was tested in Octave 5.1 and above. The content of the zip-archive is equipped with all functions to also run on older releases. In order to get all functions from the zip-archive registered properly, change to the installation folder and run the mess_path function. This will set the searchpath correctly for the current session
M-M.E.S.S. - The Matrix Equation Sparse Solver Library
No full text<p>The M-M.E.S.S. toolbox provides solvers for large-scale, sparse, symmetric linear and quadratic matrix equations. These can be algebraic and differential equations and the solvers are in their core all based on the low-rank ADI method. M-M.E.S.S. can be seen as the successor to the LyaPack toolbox with an improved formulation of the ADI, that now properly supports generalized state space systems, but also special structured DAEs. It features additional solvers for differential equations, improved shift parameter computation and a guarantee to compute real low-rank factorizations, but follows the same general philosophy of user supplied functions that the LyaPack toolbox used.</p>The Software is provided as a Matlab toolbox (mltbx) file, an Octave package (tar.gz) and a zip-archive. The toolbox-file needs a recent Matlab version to install properly. The Octave package was tested in Octave 5.1 and above. The content of the zip-archive is equipped with all functions to also run on older releases. In order to get all functions registered properly, change to the installation folder and run the mess_path function. This will set the searchpath correctly for the current session
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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