1,720,959 research outputs found
Block sweeping methods (source code)
No full text<p>This is a library of algorithms for the eikonal equation solution. It includes implementations of proposed parallel block sweeping methods [1] optimized for multicore CPUs. These methods are based on the fast sweeping method (FSM) [2] and the locking sweeping method (LSM) [3] numerical algorithms. Proposed methods achieve high parallel efficiency due to optimization of task synchronization and CPU cache use. The library also includes implementations of FSM and LSM as well as another parallel algorithm DFSM presented in [4]. For more information see conference abstract [1], we have also submitted an extended article for review and publication and are hoping to publish it in 2017. We are planning to improve this library in the future, for latest versions go to https://github.com/aanikitin/seis-eikonal.</p>
<p>References:</p>
<p>1) Nikitin Alexandr A., Serdyukov Alexandr S., Duchkov Anton A. Optimization of parallel sweeping methods of numerical computation of seismic wave travel times for shared memory computing systems // ИНТЕРЭКСПО ГЕО-СИБИРЬ. – 2016. – V. 2. – N. 1. – P. 241-245.</p>
<p>2) Zhao, H.: A fast sweeping method for eikonal equations. Mathematics of computation 74(250), 603-627 (2005)</p>
<p>3) Bak, S., McLaughlin, J., Renzi, D.: Some improvements for the fast sweeping method. SIAM Journal on Scientific Computing 32(5), 2853-2874 (2010)</p>
<p>4) Detrixhe, M., Gibou, F., Min, C.: A parallel fast sweeping method for the eikonal equation. Journal of Computational Physics 237, 46-55 (2013)</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
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
Psychometric analysis of Lawson's test of formal reasoning
No full textThe thesis discusses the concept of formal reasoning and determination of its level. The content of the thesis was processing of data from the Czech republic, which was collected via Lawson's test of formal reasoning. Psychometric analysis of the questions and the test as a whole was made using the Classical Test Theory and Item Response Theory. Also detailed distractor analysis, including commentary offering a possible reason respondent might have chosen said distractor, was made. Next was determination of the level of formal reasoning of our respondents, who were Czech elementary level students. Lastly, comparison of our results with the results of Czech and foreign studies was made
Psychometric analysis of Lawson's test of formal reasoning
No full textThe thesis discusses the concept of formal reasoning and determination of its level. The content of the thesis was processing of data from the Czech republic, which was collected via Lawson's test of formal reasoning. Psychometric analysis of the questions and the test as a whole was made using the Classical Test Theory and Item Response Theory. Also detailed distractor analysis, including commentary offering a possible reason respondent might have chosen said distractor, was made. Next was determination of the level of formal reasoning of our respondents, who were Czech elementary level students. Lastly, comparison of our results with the results of Czech and foreign studies was made.V předložené diplomové práci se zabýváme pojmem vědecké myšlení a problematikou určení úrovně vědeckého myšlení. Náplní práce bylo zpracování dat z České republiky, která byla shromážděná Lawsonovým testem vědeckého myšlení. Byla provedena psychometrická analýza úloh i celého testu, použita byla klasická teorie testů a Item Response Theory. Mimo jiné došlo k podrobnému analyzování distraktorů včetně komentářů nabízejících vysvětlení jejich volby respondenty. Následovalo určení úrovně vědeckého myšlení respondentů, tedy žáků českých základních škol a gymnázií. Na závěr bylo provedeno srovnání našich výsledků s výsledky českých i zahraničních studií.Katedra didaktiky fyzikyDepartment of Physics EducationMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Physics demonstrations for upper secondary school students - a video study
Full text linkNázev práce: Fyzikální pokusy pro střední školy - videostudie Autor: Bc. Alexandr Nikitin Katedra / Ústav: Katedra didaktiky fyziky Vedoucí diplomové práce: RNDr. Marie Snětinová, Ph.D., Katedra didaktiky fyziky Abstrakt: Experiment je základním prvkem nejen ve fyzice jako vědě, ale také ve výuce fyziky. Přestože je poslední dobou více pozornosti věnováno samostatnému experimentování žáků, významnou roli ve školách stále hraje demonstrační experiment. Na katedře didaktiky fyziky MFF UK má projekt předvádění demonstračních experimentů pro studenty středních škol tradici více než 30 let a v současné době nabízí celkem sedm tematických celků. Předchozí výzkum provedený na vzorku cca 5100 studentů však ukázal, že tyto tematické celky jsou studenty vnímány poměrně odlišně zejména z hlediska jejich zájmu, vnitřní motivace a subjektivně vnímané užitečnosti a hodnoty. Nabízí se tedy otázka, zda existují parametry, které předurčují pozitivní vnímání demonstračních pokusů studenty - ať už by mělo jít o požadavky na lektora, o způsob práce s publikem či o výběr jednotlivých experimentů. Cílem této práce je představit videostudii zabývající se analýzou těchto vystoupení, jejíž výsledky poslouží k hledání předestřených parametrů. V práci je popsána metodologie tvorby kategoriálního systému užitého ve videostudii,...Title: Physics demonstrations for upper secondary school students - video study Author: Bc. Alexandr Nikitin Department: Department of Physics Education Supervisor: RNDr. Marie Snětinová, Ph.D., Department of Physics Education Abstract: Experiment is a key element not only for physics as science, but also for physics education. Even though attention has been lately focused more on students' hands-on experiments, demonstration experiments still play an important role in today's education. Department of Physics Education (Charles University, Faculty of Mathematics and Physics) has been performing physics demonstrations for upper secondary school students for more than 30 years. Seven different topics are currently offered by the Department. A survey conducted on a population of est. 5,100 students showed that the perception of these topics by students varies quite significantly, especially considering their intrinsic motivation and subjectively perceived value and usefulness of a given topic. The questions at hand are whether parameters that influence students' perception in negative or positive way do exist and how they are related to the choice of the experiments themselves or the lecturer's work with the audience. Aim of this thesis is to present a video study conducted on video recordings of all seven...Katedra didaktiky fyzikyDepartment of Physics EducationMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
Physics demonstrations for upper secondary school students - a video study
Full text linkNázev práce: Fyzikální pokusy pro střední školy - videostudie Autor: Bc. Alexandr Nikitin Katedra / Ústav: Katedra didaktiky fyziky Vedoucí diplomové práce: RNDr. Marie Snětinová, Ph.D., Katedra didaktiky fyziky Abstrakt: Experiment je základním prvkem nejen ve fyzice jako vědě, ale také ve výuce fyziky. Přestože je poslední dobou více pozornosti věnováno samostatnému experimentování žáků, významnou roli ve školách stále hraje demonstrační experiment. Na katedře didaktiky fyziky MFF UK má projekt předvádění demonstračních experimentů pro studenty středních škol tradici více než 30 let a v současné době nabízí celkem sedm tematických celků. Předchozí výzkum provedený na vzorku cca 5100 studentů však ukázal, že tyto tematické celky jsou studenty vnímány poměrně odlišně zejména z hlediska jejich zájmu, vnitřní motivace a subjektivně vnímané užitečnosti a hodnoty. Nabízí se tedy otázka, zda existují parametry, které předurčují pozitivní vnímání demonstračních pokusů studenty - ať už by mělo jít o požadavky na lektora, o způsob práce s publikem či o výběr jednotlivých experimentů. Cílem této práce je představit videostudii zabývající se analýzou těchto vystoupení, jejíž výsledky poslouží k hledání předestřených parametrů. V práci je popsána metodologie tvorby kategoriálního systému užitého ve videostudii,...Title: Physics demonstrations for upper secondary school students - video study Author: Bc. Alexandr Nikitin Department: Department of Physics Education Supervisor: RNDr. Marie Snětinová, Ph.D., Department of Physics Education Abstract: Experiment is a key element not only for physics as science, but also for physics education. Even though attention has been lately focused more on students' hands-on experiments, demonstration experiments still play an important role in today's education. Department of Physics Education (Charles University, Faculty of Mathematics and Physics) has been performing physics demonstrations for upper secondary school students for more than 30 years. Seven different topics are currently offered by the Department. A survey conducted on a population of est. 5,100 students showed that the perception of these topics by students varies quite significantly, especially considering their intrinsic motivation and subjectively perceived value and usefulness of a given topic. The questions at hand are whether parameters that influence students' perception in negative or positive way do exist and how they are related to the choice of the experiments themselves or the lecturer's work with the audience. Aim of this thesis is to present a video study conducted on video recordings of all seven...Department of Physics EducationKatedra didaktiky fyzikyMatematicko-fyzikální fakultaFaculty of Mathematics and Physic
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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