1,721,175 research outputs found
Convergence characteristics of temperature in radiation problems
No full textNumerical convergence of temperature in radiation problems with absorbing, emitting,and nonscattering media is examined. Iteration processes for the solution of blackbody intensity (or temperature) when using the pointwise or the control-volume energy equation are scrutinized and a sufficient condition for convergence is presented. An explicit and a few implicit methods for prescribed heat source distribution in one-, two-, and three-dimensional enclosures are devised. They are incorporated and tested with the discrete ordinates method, the discrete ordinates interpolation method [1], and the zone method, and comparison of the number of iterations for convergence as well as the solution accuracy is made. The implicit methods significantly reduce the number of iterations, and this is prominent for optically thick cases. However, they reduce the number of iterations marginally as the number of control volumes increases. A fully implicit scheme reduces the number of iterations more effectively than a semi-implicit one does. Also, taking finer (and thus more) control volumes increases the number of explicit iterations asymptotically, reaching all upper bound as a function of the total optical thickness and the convergence criterion
Data-driven haptic modeling of normal interactions on viscoelastic deformable objects using a random forest
No full textIn this letter, we propose a new data-driven approach for haptic modeling of normal interactions on homogeneous viscoelastic deformable objects. The approach is based on a well-known machine learning technique: Random forest. Here, we employ a random forest for regression. We acquire discrete-time interaction data for many automated cyclic compressions of a deformable object. A random forest is trained to estimate a nonparametric relationship between the position and response forces. We train the forest on very simple normal interactions. Our results show that a model trained with just 10% of the training data is capable of modeling other unseen complex normal homogeneous interactions with good accuracy. Thus, it can handle large and complex datasets. In addition, our approach requires five times less training data than the standard approach in the literature to provide similar accuracy.11Nsciescopu
Mussel-inspired complex coacervate for bone morphogenetic protein-2 immobilization
No full textNone11sci
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
Discrete Ordinate Interpolation Method for Solution of Radiative Transfer Equation in Arbitraty 2-D Geometry and Unstructured Grid
No full textThe discrete ordinates interpolation method developed for numerical of radiative transfer equation is applied to unstructured grid system in arbitrary two dimensional geometry. Basic solution method is briefly explained and five sample geobetries with absorbing-emitting and nonscattering media with a uniform temperature are taken to demonstrate the applicability and accuracy. The typical optical depths in the problem are from highly transparent cases(0.1) to highly thick cases(about 10). In the first problem, a triangle is treated with triangular grid lines. The wall heat flux is calculated and compared with the exact solution. Th e error is less than a percent with about 60 grid points. In the second problem, a quadrilateral enclosure with either unstructured or structured grids are taken. Both grids show good agreement with the exact solution with a maximum of about 1 percent error, when the number of grids is roughly 100 for both of them. A hexagonal geometry is taken to employ a mixture of different kinds of grid, and sililar accuracy in the wall heat flux as the preceding geometries with comparable density of the grids is obtained too. The fourth problem with a J-shaped enclosure shows th most complicated distribution of heat flux, however, it is successfully calculated within the resolution square geometry with structured of imbedded grids. The computational accuracy is higher for finer grids, however, the imbedded grids can significantly reduce the computation time with similar accuracy compared with the structured dense grid system. In all of the tested cases, the effect of the optical depth is relatively small and no general tendency with the optical depth is observed. The results successfully reveal the applicability of the discrete ordinates interpolation method for any geometry and optical depth. Any grid system employed in FDM, FEM or FVM may be thus adopted and any desired level of numerical accuracy can be obtained with finer of imbedded grids
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
- …
