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Prototype manufacturing of upper limb prosthesis with five active joints for shoulder disarticulated amputees
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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
Experimental characterization of prosthetic mechanisms with one-degree of freedom
No full textThis paper deals with experimental tests performed on three mechanisms with one degree of freedom employed as powered articulations of prostheses for upper limb amputees. The purpose of the experimental characterization was to evaluate the mechanism performance and quality by means of proper parameters in order to objectively assess the effects of possible modifications of the mechanism design. To this aim two parameters were chosen: the Global Efficiency ηg, intended as the ratio of the total output energy (Lu) to the total input energy (Le) supplied during a test trial, and the Mechanical Efficiency ηm, that is the ratio of the output energy Lu to the mechanical energy Lm provided by the motor that drives the mechanism. By defining the Electrical Efficiency ηel, as the ratio between the mechanical energy Lm provided by the motor and the input electrical energy Le it holds: ηg = Lu/Le = (Lu/Lm) (Lm/Le) = ηel ηm.
During the test trials, the mechanisms were driven to execute specific operative load cycles, corresponding to a trajectory of the followers from an initial position to a final different one, with initial and final velocity equal to zero, and with a mono-directional flow of the energy, i.e. the mechanism actuator works exclusively as a motor to equilibrate the external load which always has a resistant role.
The procedure to experimentally evaluate ηg and ηm of mechanisms working in such operative conditions is shown and discussed. In particular, it is based on the theoretical calculation of Lu (that is straightforward if the loads acting on the mechanism, its kinematic scheme and the trajectory of the operative load cycles are known), on the experimental measure of Le, and finally on the implementation of a proper model of the motor Electrical Efficiency (that depends on the motor characteristics, to be known, and its working conditions to be experimentally detected).
The test bench used to apply the method is only required to acquire the supply voltage and current of the motor, and the mechanism follower velocity. Therefore, the bench is simple and rather cheap and the procedure to integrate the experimental data and theoretical calculations is straightforward.
The paper also outlines in some detail the application of the method to the three prosthetic devices mentioned above, i.e. two mechanisms for a shoulder articulation (which is at a prototype stage) and an elbow joint (which is a more mature product, but still in evolution). Different test sessions were performed on each mechanism, varying the follower mean velocity and the maximum value of the applied load (that is not constant during a given trajectory) with the purpose of investigating the effects of increasing work rate and speed of movement on the mechanism efficiency. The corresponding results are reported and 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
Kinematic and Kinetostatic Synthesis of a Prosthetic Shoulder Mechanism for Upper Limb Amputees
No full textThis study reports the application of an original procedure developed by the authors for the determination of the optimal prosthesis architecture for a given upper limb amputee. In particular, the procedure has been used to provide the main guidelines for the design of a prosthetic shoulder mechanism for externally powered prostheses. The topology and the geometry of the artificial articulation have been determined as the optimal compromise solution between functionality and wearability (for the patient’s comfort). This choice is based on kinematic and kinetostatic simulations of upper limb prosthesis models and on quantitative criteria (in the form of purpose-build indices). The application of the procedure to the examined case is outlined
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