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Validierung prädiktiver und funktionaler Methoden zur Lokalisierung des Mittelpunktes des menschlichen Hüftgelenkes
Get PDFThe location of the hip joint centre (HJC) is essential for calculations of hip moments, orientation of the femur and muscular lever arms. In clinical gait analysis, the HJC is normally estimated using predictive methods based on regression equations and anthropometric data. However, predictive methods are known to have limited accuracy with errors up to 3 cm. Functional methods for estimation of HJC are shown to be theoretically more accurate than predictive methods. In simulation tests errors in HJC location were smaller than 1 mm using functional methods. The accuracy of functional methods applied in realistic testing conditions has not been investigated systematically.
Therefore the aims of the study were (1) comparing accuracy of functional methods in simulation tests and realistic testing conditions, (2) comparing accuracy of functional and predictive methods and (3) quantifying how mislocation errors propagate to gait analysis results.
Eight predictive and two functional methods were tested: a quartic sphere-fit-method (S4) and a two-sided transformation technique (SCoRE). HJC estimation was validated by MRI of 27 subjects and a mechanical linkage. Gait analysis was performed at different speeds.
Errors of functional methods applied to mechanical linkage were smaller than 1 mm. Errors of functional methods applied to subjects were 11 - 13 mm (SCoRE) and 19 - 22 mm (S4). Errors of predivtive methods were between 11 and 22 mm. Kinetic and kinematic parameters of hip and knee were influenced by HJC mislocation.
The main findings of this study were that functional methods are more accurate in simulation tests than in realistic testing conditions. This seems to be caused by soft tissue artefacts. In this study functional methods were not significantly more accurate than all of the predictive methods. Functional methods may be improved by implementing optimization methods to reduce soft tissue artefacts.
This study can be used to establish applications of functional methods in movement analyses and therefore to improve estimations of kinetic and kinematic parameters.
Zur Durchführung von Bewegungsanalysen ist die Lagekenntnis von Gelenkmittelpunkten erforderlich, um Winkel und Momente eines Gelenkes berechnen zu können. Die präzise Lagebestimmung des Hüftgelenkmittelpunktes (HGM) stellt ein noch ungelöstes Problem biomechanischer Forschung dar. Zur Lageschätzung des HGM werden standardmäßig prädiktive Methoden verwendet, die auf empirischen Relationen zwischen anthropometrischen Daten und Lage des HGM beruhen. Aus Validierungsstudien prädiktiver Methoden ist jedoch bekannt, dass diese Methoden Fehler bis zu 3 cm aufweisen. Zur HGM-Lagebestimmung werden in der Literatur funktionale Methoden vorgestellt, die in theoretischen Überprüfungen Fehler unter 1 mm aufweisen. Die Anwendbarkeit funktionaler Methoden ist jedoch nicht systematisch untersucht.
Daher war das Ziel dieser Studie, Präzision und Anwendbarkeit von prädiktiven und funktionalen Methoden zu validieren und somit dazu beizutragen, ein präziseres Verfahren als bislang möglich zur Bestimmung des HGM im Rahmen von Bewegungsanalysen zu etablieren.
Acht prädiktive und zwei funktionale (sphere-fit-Technik S4, Transformationstechnik SCoRE) Methoden wurden anhand von MRT-Aufnahmen von 27 Probanden validiert. Die funktionalen Methoden wurden zusätzlich an einem mechanischen Modell unter Ausschluss von Bewegungsartefakten validiert. Basierend auf den berechneten HGMen wurden kinetische und kinematische Parameter von Gang und Lauf berechnet.
Die Fehler der funktionalen Methoden am mechanischen Modell lagen im Bereich unter 1 mm. Die Fehler der funktionalen Methoden in der Anwendung an Probanden lagen bei 11 - 13 mm (SCoRE) bzw. 19 - 22 mm (S4). Die Fehler der prädiktiven Methoden lagen zwischen 11 und 22 mm. Kinetische und kinematische Parameter der Gang- und Laufanalysen wurden durch die HGM-Lageschätzung beeinflusst.
In dieser Studie konnte gezeigt werden, dass funktionale Methoden unter Ausschluss von Bewegungsartefakten deutlich präziser arbeiten als unter realen Versuchsbedingungen. In der Anwendung an Probanden zeigten sich funktionale Methoden nicht systematisch präziser als prädiktive Methoden. Die Hauptfehlerquelle der funktionalen Methoden scheinen Bewegungsartefakte darzustellen. Diese lassen sich durch die Anwendung von Optimierungsverfahren rechnerisch minimieren, so dass ein erhebliches Verbesserungspotential funktionaler HGM-Lagebestimmung zu erwarten ist.
Diese Arbeit bietet die Grundlage dafür, die Anwendung funktionaler Methoden in Bewegungsanalysen zu integrieren und somit eine Qualitätsseigerung von Bewegungsanalysen zu erreichen
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
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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