1,720,962 research outputs found
Identification of multiple U-turns using gyroscopes : comparative assessment of two methods
No full textThe identification of turnings segments during walking trials including the U-turns represents the first preliminary step required for the analysis of gait featuring straights and turns. To this purpose IMU-based methods were developed, however many of them rely on the a-priori knowledge of the number of turns. In this study, we selected two methods and compared them to evaluate their ability to detect the number of turns in continuous gait with multiple U-turns without further assumptions. Gyroscope data were recorded during gait trials performed at different speeds by two groups of subjects (healthy elderly and patients with Parkinson disease). Results show that the method that employs a sensor on the back yields better results than the one making use of a sensor on the ankles
Application of a markerless gait analysis methodology in children with cerebral palsy: Preliminary results
No full textIdentification of multiple U-turns using IMUs: Comparative assessment of three methods
No full textDaily life locomotion includes sequences of straight and turn walking bouts. Wearable inertial measurement units (IMU) allow to extend the traditional gait analysis to tasks including turns. In this context, the preliminary goal of any IMU-based methodology is the identification of turns, thus allowing the trial segmentation into straight and turn bouts. Various methods have been proposed to identify turns in walking trials with a known number of turns. The aim of this study was to verify the applicability of three published methods to gait trials with an unknown number of turns, and to patients with different kinds of pathologies affecting gait. Results show that none of the methods was 100% accurate in detecting turns
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
Can MIMUs positioned on the ankles provide a reliable detection and characterization of U-turns in gait?
No full textThe detection and characterization of U-turns during locomotion using Magneto-Inertial Measurement Units (MIMU) with the goal of segmenting the walking trial into straight walking bouts and turns is an open issue currently under investigation. Typically, a MIMU located on the lower back or trunk is used to this purpose and turns onset timing and duration are determined. The aim of this study was to assess if an existing method could be satisfactorily applied to signals recorded from MIMUs near the ankles. Additionally, a method is proposed with the aim of limiting the differences of its output from that of the existing method guaranteeing high robustness with respect to the MIMU location. The analysis was conducted on data recorded from healthy elderly subjects and patients with Parkinson's disease walking at two different speeds. The existing method applied to signals from the MIMU near the ankles could detect the same number of U-turns as the original. However, their onset and duration were often more than 200ms away from those obtained with the original method. Similar results were obtained with the proposed method, showing some limitations in part related to the heuristic threshold employed. However, the proposed method demonstrated a superior robustness with respect to the MIMU location. Overall, the proposed method appears to be a good starting point for the definition of a more stable and robust method for U-turn detection and characterization from signals recorded from MIMUs near the ankles
The identification of multiple U-turns in gait : comparison of four trunk IMU-based methods
No full textThe identification of turns during walking allows for the segmentation into straight and turn walking bouts. Several IMU-based methods were developed to this purpose, however many of them were tested on specific subject population. In this study, we tested four methods for the identification of turns in walking tasks with multiple U-turns that did not exploit any a-priori knowledge of the turn occurrences. We evaluated their robustness by recording IMU data on healthy and pathological subjects (healthy elderly, stroke survivors, patients with Parkinson disease and choreic patients) walking at two different speeds along a closed loop formed by straight bouts and U-turns. Overall, all methods identified correctly the totality of the U-turns when elderly and Parkinsonian patients were analyzed. When stroke survivors and choreic patients were analyzed, U-turns were either missed or erroneously detected in a limited number of cases. The only method using the magnetometer signals was the best performing, highlighting the usefulness of the magnetometer when turns are being investigated
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
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