1,720,986 research outputs found
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
Deformation simulation results of Capriccio method coupled systems for conducting comparative one- and multidimensional studies on the coupling of the finite element method with particle-based techniques
No full text<p>readme_3Dresults.txt</p>
<p><br>
<strong>Description</strong>:</p>
<p>This readme explains the content and path structure of the results obtained from a<br>
deformation test conducted on slightly different MD-FE coupled systems performing the<br>
Capriccio method in a three-dimensional space within the associated project thesis [1],<br>
published on the following dataset: <a href="https://doi.org/10.5281/zenodo.7924367">https://doi.org/10.5281/zenodo.7924367</a></p>
<p>Furthermore, input files and parameters as well as potential tables required to reproduce<br>
the obtained data are provided as well.</p>
<p>The molecular dynamics (MD) part is executed in LAMMPS and the finite element (FE) method<br>
part by a MATLAB script as described in Section 4.1 of [1]. The whole setup of the 3D<br>
models is elaborated in Section 4.2 of [1]. A discussion of some results is given in<br>
Chapter 6 of [1] in the context of assessing their comparability with the corresponding 1D<br>
model.</p>
<p><br>
<strong>Context</strong>:</p>
<p>[1] L. Laubert, "Establishing a framework for conducting comparative one- and<br>
multidimensional studies on the coupling of the finite element method with<br>
particle-based techniques", Project Thesis, Friedrich-Alexander-Universität<br>
Erlangen-Nürnberg (FAU), 2023.</p>
<p><br>
<strong>Contact</strong>:</p>
<p>Lukas Laubert<br>
Institute of Applied Mechanics<br>
Friedrich-Alexander-Universiät Erlangen-Nürnberg<br>
Egerlandstraße 5<br>
91058 Erlangen</p>
<p><br>
<strong>License</strong>:</p>
<p>Creative Commons Attribution Non Commercial 4.0 International</p>
<p><br>
<strong>Path structure and files</strong>:</p>
<p>- The ZIP compressed files each contain a folder containing all simulation files as well as<br>
postprocessing variables:<br>
* /FE_data/ contains all output files after each FE simulation in each iteration step<br>
* /MD_data/ contains all output files after each MD simulation in each iteration step<br>
* /input_files/ contains the input FE model "cgps_dpd_c_1_2000.inp", the MD particle<br>
configurations "cgps_dpd_c_1_2000.data", the AP particle coordinates <br>
"cgps_dpd_c_1_2000.ac" as well as further Abaqus CAE FE files that<br>
can be used to adapt the present FE model<br>
* /input_parameters/ contains the parameter dataset; "Capriccio.prm" is the main parameter<br>
dataset, whose adaptations lead to similar adjustments in the other parameter files<br>
* "Capriccio_FEMD_main_meggie_WZ.sh" is a shell script for executing simulations<br>
* "job.out" is an output protocol that documents the progress of the simulations<br>
* "Job.err" is an error protocol that documents detected errors during the simulations<br>
* "log.lammps" logs MD parameter sets<br>
* "meta.info" provides version information of used softwares among few other information<br>
* "next_job.info" documents the next load step and iteration step that is to be executed<br>
when simulation jobs are restarted on the used computation cluser<br>
* **_workspace_vars.mat comprises a set of postprocessing variables obtained by executing a<br>
postprocessing script provided by Capriccio group</p>
<p>- "md_dpd_main-CBpot-writeobs-sandw.in" is an input script that further defines and loads<br>
MD simulation parameter</p>
<p>- ***_table are potential tables applied during the MD simulations<br>
* "Angle_table" lists the angle bending potential<br>
* "Bond_table" lists the bond potentials<br>
* "Nonbond_table" lists the non-bonded interaction potential</p>
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Skalenübergreifende Modellierung des Bruchverhaltens glasartiger Polymere von der atomaren zur Kontinuumsskala
Full text linkPolymer materials started to play an important role in engineering applications in the last century. Simultaneously, polymer science has been established and further developed based on experiments with polymers. In the past decades, molecular dynamics (MD) simulations have become a powerful tool to study the mechanics of these materials as a complement to experiments and thus to provide deeper insights at atomistic and molecular levels. Although MD simulations have contributed a lot to reduce the gaps between theory and experimental observations in the field of polymer mechanics, they are limited to small scales due to their computational cost. Thus, they are only appropriate for problems that eventually represent a continuum point where large-scale heterogeneities must be neglected. For problems with heterogeneous materials such as polymer-based nanocomposites or specimens subject to specific loading like fracture, a much larger, typically computationally prohibitive amount of material is to be considered in the simulations. This can be overcome by coupling MD simulations to continuum mechanics, where the molecular resolution confined to specific regions are exposed, e.g., to high loads. The remaining parts, in turn, are described at continuum resolution with less computational cost. Hence, this thesis aims to develop an atomistic-continuum coupling method for fracture simulations of glassy polymers.
The method presented in this thesis is based on the Capriccio framework designed for multiscale simulations of amorphous polymers, coupling a continuum and an MD domain in an overlapping region via energy blending together with appropriate deformation constraints. The continuum domain employs a constitutive model to resemble the macroscopic mechanical behavior of the material represented by the MD simulations. The original Capriccio method uses an elastic constitutive model and is thus limited to the elastic regime of polymers under small deformation. For fracture simulations, however, the Capriccio method is to be extended to inelasticity. This can be implemented by incorporating an appropriate constitutive model into the continuum domain, which is identified based on pure MD simulations.
The present thesis uses coarse-grained (CG) atactic polystyrene (PS) as a sample material. At first, CG MD simulations are conducted in uniaxial tension tests at different temperatures with different strain rates at large strains, where the thermal history-dependent mechanical behavior and time-temperature superposition at large deformations are investigated. With appropriate thermal history, the strain-softening effects can be reduced. Based on this, a simple isothermal viscoelastic-viscoplastic constitutive model with only 11 parameters is proposed. Incorporating this model into the continuum domain, the inelastic extension of the Capriccio method is able to simulate glassy polymers at large deformations. Since this constitutive model is rate-dependent, an appropriate temporal coupling between the MD and continuum domain has to be introduced. Furthermore, the parameters for the coupling are thoroughly studied based on multiscale simulations. Finally, two examples of fracture simulations in mode-I and three-point bending tests are presented. Although this method is developed based on the CG PS, transferability to other polymer materials and their nanocomposites is expected.Polymermaterialien begannen im letzten Jahrhundert, eine wichtige Rolle in technischen Anwendungen zu spielen. Gleichzeitig wurde die Polymerwissenschaft auf der Grundlage von Polymerexperimenten begründet und weiterentwickelt. In den letzten Jahrzehnten haben sich Molekulardynamiksimulationen (MD) zu einem leistungsfähigen Werkzeug entwickelt, um die Mechanik dieser Materialien als Ergänzung zu Experimenten zu untersuchen und somit tiefere Einblicke auf atomistischer und molekularer Ebene zu ermöglichen. Obwohl MD-Simulationen viel dazu beigetragen haben, die Lücken zwischen Theorie und experimentellen Beobachtungen auf dem Gebiet der Polymermechanik zu schließen, sind sie aufgrund des Rechenaufwands auf kleine Skalen beschränkt. Daher sind sie nur für Probleme geeignet, die de facto einen Kontinuumspunkt darstellen, in dem höherskalige Heterogenitäten vernachlässigt werden müssen. Bei Problemen mit heterogenen Materialien wie polymerbasierten Nanokompositen oder rissbehafteten Proben, ist ein viel größerer, typischerweise rechnerisch nicht erfassbarer Materialumfang in den Simulationen zu berücksichtigen. Dem kann durch die Kopplung von MD-Simulationen mit der Kontinuumsmechanik begegnet werden, bei der die molekulare Auflösung auf bestimmte Regionen beschränkt ist, die z. B. hohen Belastungen ausgesetzt sind. Die verbleibenden Bereiche wiederum werden mit Kontinuumsauflösung mit geringerem Rechenaufwand beschrieben. Daher zielt diese Arbeit darauf ab, eine atomistisch-kontinuierliche Kopplungsmethode für Bruchsimulationen von glasartigen Polymeren zu entwickeln.
Das in dieser Arbeit vorgestellte Verfahren basiert auf der Capriccio-Methode, die für Multiskalensimulationen von amorphen Polymeren entwickelt wurde und ein Kontinuum und ein MD-Gebiet in einem überlappenden Bereich durch eine gegenseitige Überblendung der Energien zusammen mit kinematischen Koppelbedingungen verknüpft. Das Kontinuum verwendet ein Materialmodell, welches das makroskopische Verhalten des durch die MD-Simulationen beschriebenen Materials möglichst genau abbildet. Die ursprüngliche Capriccio-Methode verwendet ein elastisches Materialmodell und ist daher auf den elastischen Bereich von Polymeren unter geringer Verformung beschränkt. Für Bruchsimulationen soll sie jedoch auf Inelastizität erweitert werden. Dies kann erreicht werden durch ein geeignetes Materialmodell, welches basierend auf reinen MD-Simulationen bestimmt wird.
Die vorliegende Arbeit verwendet mittels ``coarse graining'' (CG) vergröbert aufgelöstes ataktisches Polystyrol als beispielhaftes Polymer. Zunächst werden MD-Simulationen als einachsige Zugversuche bei unterschiedlichen Temperaturen mit verschiedenen Dehnungsraten bei großen Dehnungen durchgeführt, wobei temperatur- und belastungsabhängige mechanische Verhalten sowie die Zeit-Temperatur-Superposition bei großen Deformationen untersucht werden. Bei Wahl einer geeigneten temperaturabhängigen Belastungshistorie können Entfestigungseffekte reduziert werden, worauf aufbauend ein einfaches, isothermes viskoelastisch-viskoplastisches (VE-VP) Materialmodell mit 11 Parametern vorgeschlagen wird. Durch die Einbeziehung dieses Modells in das Kontinuumsgebiet ist die inelastische Erweiterung der Capriccio-Methode in der Lage, glasartige Polymere bei großen Verformungen zu simulieren. Da das VE-VP Materialmodell ratenabhängig ist, muss eine geeignete zeitliche Kopplung zwischen dem MD-Gebiet und dem Kontinuum implementiert werden. Darüber hinaus werden die Parameter für die Kopplung anhand von Multiskalensimulationen eingehend untersucht. Abschließend werden zwei Beispiele für Bruchsimulationen in Mode-I und Dreipunkt-Biegeversuchen vorgestellt. Obwohl diese Methode auf Basis von modellhaftem Polystyrol entwickelt wurde, wird eine Übertragbarkeit auf andere Polymermaterialien und deren Nanokomposite erwartet
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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