1,720,955 research outputs found
A simple momentum controller for humanoid push recovery
No full textWhile working in a dynamic environment, humanoid robots are subject to unknown forces and disturbances, putting them at risk of falling down and damaging themselves. One mechanism by which humans avoid falling under similar conditions is the human momentum reflex. Although such systems have been devised, the processing requirements are too high to be implemented on small humanoids having microcontroller processing capabilities. This paper presents a simplified momentum controller for fall avoidence. The system is tested on a simulated robot developed under Gazebo as well as under a real humanoid. Results show successful fall avoidance. © 2009 Springer.
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
Humanoid fall avoidance using a mixture of strategies
No full textIf we are to one day rely on robots as assistive devices they should be capable of mitigating the impact of random disturbances and avoid falling. Humans are surprisingly apt at remaining on their feet when pushed; they rely on reflexes such as bending the ankles and-or the hips, or by taking a step if the magnitude of the disturbance is relatively large. This paper presents a fall avoidance scheme that is capable of applying both ankle and hip strategies on a humanoid robot. While both strategies serve the same purpose, the hip strategy can absorb larger disturbances but has a higher energy overhead and should be avoided when it is not necessary. Our system is capable of detecting at the onset of a disturbance if an ankle or hip strategy is more appropriate. The decision is taken based on a 'decision surface' that is delimited by threshold values of the robot's state variables. The control is based on the Virtual Model Control (VMC) approach. The system is tested on a simulated robot developed under Gazebo as well as on a real small-scale humanoid robot. Results show successful fall avoidance with an ability to choose the optimum fall avoidance strategy. © 2012 World Scientific Publishing Company.Abdallah M., 2005, P 2005 IEEE INT C RO; Azevedo C, 2004, ROBOT AUTON SYST, V47, P203, DOI 10.1016-j.robot.2004.03.013; Hemami H., 1979, J INTERDISC MODEL SI, V2; Hyon SH, 2007, IEEE INT CONF ROBOT, P2668, DOI 10.1109-ROBOT.2007.363868; Jalgha B., 2009, LECT NOTES COMPUTER, V5744; Kanamiya Y, 2010, IEEE INT CONF ROBOT, P3446, DOI 10.1109-ROBOT.2010.5509785; Koenig N., 2004, P IEEE RSJ INT C INT, P2149; Nenchev DN, 2008, ROBOTICA, V26, P643, DOI 10.1017-S0263574708004268; Pratt G., 2006, SERIES ELASTIC ACTUA; Pratt J., 2006, P IEEE INT C HUM ROB; Pratt J., 2007, P IEEE INT C HUM ROB; Pratt J, 2001, INT J ROBOT RES, V20, P129, DOI 10.1177-02783640122067309; Pratt J. E., 2000, THESIS MIT CAMBRIDGE; Stephens B., 2007, P IEEE C INT ROB SYS; Stephens B., 2007, P IEEERAS INT C HUM; Vukpbratovic B., 2007, INT J HUM ROBOT, V18, P157; Winter D. A., 1995, GAIT POSTURE, V3, P193, DOI 10.1016-0966-6362(96)82849-910
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
Vision SLAM maps: Towards richer content
No full textSimultaneous Localization and Mapping (SLAM) is a recursive probabilistic inferencing process for concurrently building a map of a robot's surroundings and localizing that robot within this map. The ultimate goal of SLAM is to operate anywhere, allowing a robot to navigate autonomously and producing a meaningful purposeful map. Research in SLAM to date has focused on improving the localization part of SLAM, while lagging in the ability to produce useful maps. Indeed, all feature-based SLAM maps are built from either low level features such as points or lines or from artificial beacons; such maps have little use other than to perform SLAM. There are benefits in building maps from real natural objects that are indigenous of the environment for operations such as surveying of remote areas or as a guide for human navigation in dangerous settings. To investigate the potential of SLAM to produce such maps, an Inertial-Visual SLAM system is designed and used here which relies on inertial measurements to predict ego-motion and a digital camera to collect images of natural landmarks about the scene. Experiments conducted on a mobile vehicle show encouraging results and highlight the potential for Vision SLAM to generate meaningful maps which agree with ground truth. The Computer Vision system is capable of recognizing the environment type, of detecting trees within this environment, and recognizing different trees based on clusters of distinctive visual features. © 2009 Springer-Verlag Berlin Heidelberg
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
- …
