1,720,962 research outputs found
Video-analysis interface for angular joint measurement
No full textAbstract: Real-time quantification of joint articular movement is instrumental in the comprehensive assessment of significant biomechanical gestures. The development of an interface, based on an automatic algorithm for 3D-motion analysis, is presented in this work. The graphical interface uses open-source libraries for video processing, and its use is intuitive. The proposed method is low-cost, of acceptable precision (|| < 1), and minimally invasive. It allows to obtain angular movement of joints in different planes, synchronized with the video of the gesture, as well as to make comparisons and calculate parameters of interest from the acquired angular kinematicsFil: Mondani, Mariano. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Ghersi, Ignacio. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Ghersi, Ignacio. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. cidi Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Miralles, Mónica. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Miralles, Mónica. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. cidi Centro de Investigación en Diseño Industrial de Productos Complejos; Argentin
Discrete Kalman filter based sensor fusion for robust accessibility interfaces
No full textAbstract: Human-machine interfaces have evolved, benefiting from the growing access to devices with superior, embedded signal-processing capabilities, as well as through new sensors that allow the estimation of movements and gestures, resulting in increasingly intuitive interfaces. In this context, sensor fusion for the estimation of the spatial orientation of body segments allows to achieve more robust solutions, overcoming specific disadvantages derived from the use of isolated sensors, such as the sensitivity of magnetic-field sensors to external influences, when used in uncontrolled environments. In this work, a method for the combination of image-processing data and angular-velocity registers from a 3D MEMS gyroscope, through a Discrete-time Kalman Filter, is proposed and deployed as an alternate user interface for mobile devices, in which an on-screen pointer is controlled with head movements. Results concerning general performance of the method are presented, as well as a comparative analysis, under a dedicated test application, with results from a previous version of this system, in which the relative-orientation information was acquired directly from MEMS sensors (3D magnetometeraccelerometer). These results show an improved response for this new version of the pointer, both in terms of precision and response time, while keeping many of the benefits that were highlighted for its predecessor, giving place to a complementary method for signal acquisition that can be used as an alternative-input device, as well as for accessibility solutionsFil: Ghersi, Ignacio. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Ghersi, Ignacio. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Mariño, M. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Miralles, Mónica. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Miralles, Mónica. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; Argentin
Biomechanics and biotensegrity : study method and frequency response of the simplex and 3- bar-SVD tensegrity configurations
No full textAbstract: The purpose of this work is to study the frequency response of 3D tensegrity structures. These are structures that have been used, since the 80’s, to model biological systems of different scales. This fact led to the origin of the field of biotensegrity, which includes biomechanics as a natural field of application. In this work: a) A simple method for the analysis of frequency response of different nodes in 3D tensegrity structures was set up and tuned. This method is based on a video-analysis algorithm, which was applied to the structures, as they were vibrated along their axis of symmetry, at frequencies from 1 Hz to 60 Hz. b) Frequency-response analyses were performed, for the simplest 3D structure, the Simplex module, as well as for two towers, formed by stacking two and three Simplex modules, respectively. Resonant frequencies were detected for the Simplex module at (19.2± 0.1) Hz and (50.2±0.1) Hz (the latter being an average of frequencies between homologous nodes). For the towers with two and three modules, each selected node presented a characteristic frequency response, modulated by their spatial placement in each model. Resonances for the two-stage tower were found at: (12 ±0.1) Hz; (16.2±0.1) Hz; (29.4±0.1) Hz and (37.2 ± 0.1) Hz. For the tower with three Simplex modules, the main resonant frequencies were found at (12.0± 0.1) Hz and (21.0± 0.1) Hz. Results show that the proposed method is adequate for the study (2D) of any 3D tensegrity structure, with the potential of being generalized to the study of oscillations in three dimensions. A growing complexity and variability in the frequency response of the nodes was observed, as modules were added to the structures. These findings were compared to those found in the available literatureFil: Castro Arenas, Cristhian. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. Instituto de la Espacialidad Humana. Centro Laboratorio de Morfología; ArgentinaFil: Castro Arenas, Cristhian. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Castro Arenas, Cristhian. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Ghersi, Ignacio. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Ghersi, Ignacio. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Miralles, Mónica. Universidad de Buenos Aires. Facultad de Arquitectura Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Miralles, Mónica. Universidad Católica Argentina. Facultad de Ciencias Fisicomatemáticas e Ingeniería. Laboratorio de Biomecánica e Ingeniería para la Salud; Argentin
Smart medical beds in patient-care environments of the twenty-first century : a state-of-art survey
No full textAbstract: Background: Recent scientific achievements and technological advances have brought forward a massive display of new or updated medical devices, enabled with highly-developed embedded-control functions and interactivity. From the final decade of the twentieth century, medical beds have particularly been affected by this surge, taking on new forms and functions, while accommodating to established properties that have become well-known for these devices. The past fifteen years have also brought forward changes to conceptual frameworks, concerning the product design and manufacturing processes (standards), as well as the patient (perspectives on patient-care environments and accessibility). This work presents a state-of-art survey on electric medical beds, representing what is defined as the time of “smart beds”, as part of an increasingly comprehensive patient-care environment. Methods: A survey and assessment of market trends, research efforts and standards related to smart medical beds was performed, covering a wide range of public records of intellectual property, models and related healthcare solutions, as well as relevant research efforts in the field between 2000 and 2016. Contextual topics, necessary for the understanding of this subject, on novel technologies, disability and the reach of healthcare systems, were also researched and interpreted. Results: The new generation of electric medical beds is defined, with the final stage of the proposed timeline for these devices being covered. Functional, aesthetic and interactive features are presented, and the current global market for medical beds and related standards are also assessed. Finally, discussions concerning rising challenges and opportunities for these systems are explored, with the potential for adding further monitoring and assistive implementations into medical devices and environments being highlighted. Conclusions: Smart medical beds are integrated solutions for patient care, assistance and monitoring, based on a comprehensive, multidisciplinary design approach. Research in this field is critical in a context of global ageing, and powered by a surge in opportunities for accessibility solutions. Smart beds, seamlessly integrated into the healthcare system, have a unique opportunity in enabling more efficient efforts for caregivers, and more responsive environments for patients.Fil: Ghersi, Ignacio. Universidad de Buenos Aires. Facultad de Arquitectura, Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Ghersi, Ignacio. Pontificia Universidad Católica Argentina. Facultad de Ingeniería y Ciencias Agrarias. Laboratorio de Biomecánica e Ingeniería para la Salud; ArgentinaFil: Mariño, Mario. Universidad de Buenos Aires. Facultad de Arquitectura, Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Miralles, Mónica. Universidad de Buenos Aires. Facultad de Arquitectura, Diseño y Urbanismo. Centro de Investigación en Diseño Industrial de Productos Complejos; ArgentinaFil: Miralles, Mónica. Pontificia Universidad Católica Argentina. Facultad de Ingeniería y Ciencias Agrarias. Laboratorio de Biomecánica e Ingeniería para la Salud; Argentin
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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