1,720,996 research outputs found
A wired actuated elbow for human prosthesis
No full textThe mechatronic solutions used in robotic field are more and more used in other areas. Conspicuous research teams are working on arm prosthesis, investigating and developing new mechanical architecture and actuator. The mean aspect is to set up mechanical devices, actuators and energy supply. This paper presents a new mechanical elbow to install on artificial arm for human prosthesis. The device is based on 3 hydraulic actuators connected through some wires to the following forearm components. A complex and optimized path of wires makes actuators work with almost constant linearity between extensions of pistons and flexion-extension and pronation-supination angles. A kinematic 3D virtual model is presented at a second step of geometrical optimization. The authors decided to use redundant actuators, 3 instead of 2, to modulate the mechanical compliance of the artificial arm depending on the kind of operation the patient will wish perform. Moreover, in parallel, the authors are working with the third piston that collaborates with the others to optimize the volume and minimize the stresse
A high performance wire device for an elbow prosthesis
No full textNew requirements for human powered prostheses are energetic autonomy, low production cost and human like behavior. Several teams are developing new solutions for bionic arms, usually based on serial mechanisms. On the scientific panorama very few examples of parallel device are available. We present an alternative device, with a simple mechanical hardware, to simulate human elbow movements. The parallel architecture avoids the requirement of a full size actuator to perform flexion/extension movement. The wire transmission architecture allows two linear actuators to control the motion of the forearm among two degrees of freedom in an improved work volume. The device, indeed, is designed to provide also pronation/supination movement, that is usually provided by the wrist in common commercial products. The choice of power source is oriented to a mixed fluid actuation, in which pressurized gas transfer power to incompressible fluid, in order to get a non-back power transmission. To increase energetic autonomy, a hydro-pneumatic circuit is set up with capability to recover energy coming by passive movements. Energetic recover is never tried in arm prosthesis at the state of the art and it could be a future innovative featur
Educazione alla sessualità nella scuola media: un'esperienza di formazione degli insegnanti
No full textDesign and analysis of a tendon-driven 2 DOF elbow prosthesis hybrid mechanism
No full textThis paper presents a new mechanical architecturefor elbow powered myoelectric
prostheses. New requirements for active prostheses are energetic autonomy, low production
cost and human like behavior. On the scientific panorama very few examples of parallel
device are available. We show an alternative device, with a simple mechanical hardware, to
simulate the movements and the dynamic of human elbow. We investigated on wires used
like tendons in mechanical elbow prostheses. The wire transmission architecture allows two
linear actuators to control the motion of the forearm along two degrees of freedom in an
enhanced work volume. The device, indeed, is designed to provide in the same mechanism
flexion/extension and pronation/supination movement, which are usually decoupled in elbow
and wrist mechanisms in usual commercial devices
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
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