1,721,214 research outputs found
Novel approaches to statistical shape modelling of bone
Full text linkThe femur is the longest bone in the human body and serves the important
purposes of load-bearing and allowing bipedal locomotion.
Accurate modelling of the variation in shape within the healthy adult population
can be useful for a variety of applications: from the mere anatomical
description of its features, in order to better understand its function, to more
complex tasks such as pathology detection or surgical planning.
Statistical Shape Modelling (SSM) is a well-established technique that
enables to capture the variability within a set of training shapes and describes
it with a reduced set of variables.
The aim of this thesis is to evaluate the performance of a SSM based
on a point cloud representation of shape, and introduce and test subsequent
improvements to the modelling process that can increase its clinical relevance
and scope of application.
The standard approach to SSM employs a dimension-reducing technique,
generally by means of Principal Component Analysis (PCA). However, this
approach favours the compactness of the model, thus not focusing on other
aspects that may be more relevant to clinical practice.
Although rotation of the principal components is commonly performed as
a post-processing step in statistical analysis involving PCA, it is not routinely
applied in SSM.
By applying this class of rotation, the components' effects are more localised,
allowing a better interpretation, understanding and classification of pathological deformities.
Among other possible representations, the Medial Axis Transform (MAT)
could offer a further insight into shape modelling, since it allows the information
about thickness to be decoupled from the rest of the shape.
SSMs based on this representation can lead to a di erent perspective
on the understanding of femoral anatomy and function,and can also enable
the reconstruction of the complete anatomy starting from a reduced set of
features, with diverse applications in the elds of surgical planning, forensic
science and paleontology
Tracking scapular movement
Full text linkMeasuring the three-dimensional movement of the scapula provides vital information in
the analysis and treatment of shoulder clinical disorders and contributes to our
understanding of its complex kinematics. However, the thick layer of skin overlying the
scapular region means that all skin-based techniques inaccurately determine the scapular
kinematics. The scapula locator makes use of a palpation technique in order to reduce the
problem of skin deformation. At present, the scapula locator is the most accurate noninvasive
method of measuring scapular movements, but to date the method has only been
used to measure the scapula position statically.
Here, a new method was developed to measure the scapula movements dynamically; the
method makes use of the scapula locator and feedback from pressure-sensors attached to
the locator probes to track the scapula during movement. The reliability of the method
after short-term practise as well as the intra-observer and inter-observer variations and the
inter-session repeatability were tested and quantified in a series of studies.
The method was found to be able to measure dynamic scapular movements in slow to
medium paced arm movements to a good degree of accuracy as well as provide
scapulothoracic measurements of high reliability compared to using the scapula locator
on its own and to previously reported results in the literature.
Finally, the new locator method was used to calibrate the acromial tracker in order to
improve the accuracy of the device and facilitate its use as an alternative to the scapula
locator in clinical studies involving fast (higher than functional velocities) dynamic
activities.
The new scapula locator method and the calibrated acromial tracker method present
significant improvements on the available scapular measurement techniques particularly
in measuring subtle scapular rotations of clinical importance, such as the scapular tilt. The
methods described will be used in future clinical and sport-related studies
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
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
- …
