1,721,063 research outputs found
A Higher-Order Method for Dynamic Optimization of Controllable Linear Time-Invariant Systems
No full textThis work describes a new procedure for dynamic optimization of controllable linear time-invariant (LTI) systems. Unlike the traditional approach, which results in 2n first-order differential equations, the method proposed here yields a set of m differential equations, whose highest order is twice the controllability index of the system p. This paper generalizes the approach presented in a previous work to any controllable LTI system
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
Sophia-3: a semi-adaptive cable-driven rehabilitation device with tilting working plane
No full textSophia-3 (String Operated Planar Haptic Interface for Armrehabilitation) is a planar cable-driven device with a tilting working plane.
It represents the first application of the adaptive cable-driven design paradigm recently introduced by the authors, featuring a moving pulley-block that allows the robot to achieve excellent force capabilities despite the low number of cables.
This work presents the design, kinematics and control of the device, and results of experimental validation on healthy subject
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
Performance analysis of planar cable-based parallel manipulators
No full textIn the last two decades, many research works have been published on cable-based systems, reflecting the considerable interest of the scientific community in this area. Cables are used both in serial structures, to remotely actuate rigid links, and in parallel structures, to directly control the motion of a mobile platform or end-effector. The latter subclass is particularly appealing, thanks to ease of design, high payload-to-weight ratio, potentially high dynamic performances and wide workspace. Such devices have also been effectively employed in haptics, since the use of light-weight elements allows to develop structures with low mechanical impedance. Unilateral actuation represents a major issue in the study of cable-based devices, often forcing to adopt specially formulated design tools. This paper presents a set of performance indices, some of which are introduced here for the first time, that can be used for the optimization of the design and for the analysis of cable-based devices. To prove the effectiveness of these tools, a comparison of the kinematic and dynamic performances of three different designs of planar cable-based parallel manipulators is presented.</jats:p
A higher-order method for dynamic optimization of controllable LTI systems
No full textThis work describes a new procedure for dynamic optimization of controllable Linear time-invariant (LTI) systems. Unlike the traditional approach, which results in 2n first order differential equations, the method proposed here yields a set of m differential equations, whose highest order is twice the controllability index of the system p. This paper generalizes the approach presented in a previous work to any controllable LTI system
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