1,721,180 research outputs found
Integrating Human-Like Impedance Regulation and Model-Based Approaches for Compliance Discrimination via Biomimetic Optical Tactile Sensors
No full textEndowing robots with advanced tactile abilities based
on biomimicry involves designing human-like tactile sensors,
computational models, and motor control policies to enhance
contact information retrieval. Here we consider compliance
discrimination with a soft biomimetic tactile optical sensor
(TacTip). In previous work, we proposed a vision-based approach
derived from a computational model of human tactile perception
to discriminate object compliance with the TacTip, based on
contact area spread computation over the indenting force. In
this work, we first increased the robustness of our vision-based
method with a more precise estimation of the initial contact
area condition, which enables correct compliance estimation
also when the probing direction is other than normal to the
specimen surface. Then, we integrated within our validated
framework the mechanisms of internal muscular regulation
(co-contraction) that humans adopt during object compliance
probing, to maximize the information uptake. To this aim, we used
human co-contraction patterns extracted during object softness
probing to control a Variable Stiffness Actuator (that emulates
the agonistic-antagonistic behavior of human muscles), which is
used to actuate the indenter system endowed with the TacTip
for object compliance exploration. We found that our modelbased approach for compliance discrimination, fed with more
precisely estimated initial conditions, significantly improves with
the human-inspired impedance regulation, with respect to the
usage of a rigid actuator
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Towards integrated tactile sensorimotor control in anthropomorphic soft robotic hands
Get PDFIn this work, we report on the integrated sensorimotor control of the Pisa/IIT SoftHand, an anthropomorphic
soft robot hand designed around the principle of adaptive
synergies, with the BRL tactile fingertip (TacTip), a soft
biomimetic optical tactile sensor based on the human sense
of touch. Our focus is how a sense of touch can be used to
control an anthropomorphic hand with one degree of actuation,
based on an integration that respects the hand’s mechanical
functionality. We consider: (i) closed-loop tactile control to
establish a light contact on an unknown held object, based
on the structural similarity with an undeformed tactile image;
and (ii) controlling the estimated pose of an edge feature of
a held object, using a convolutional neural network approach
developed for controlling other sensors in the TacTip family.
Overall, this gives a foundation to endow soft robotic hands with
human-like touch, with implications for autonomous grasping,
manipulation, human-robot interaction and prosthetics
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Threshold learning for optimal decision making
Get PDFDecision making under uncertainty is commonly modelled as a process of competitive stochastic evidence accumulation to threshold (the drift-diffusion model). However, it is unknown how animals learn these decision thresholds. We examine threshold learning by constructing a reward function that averages over many trials to Wald's cost function that defines decision optimality. These rewards are highly stochastic and hence challenging to optimize, which we address in two ways: first, a simple two-factor reward-modulated learning rule derived from Williams' REINFORCE method for neural networks; and second, Bayesian optimization of the reward function with a Gaussian process. Bayesian optimization converges in fewer trials than REINFORCE but is slower computationally with greater variance. The REINFORCE method is also a better model of acquisition behaviour in animals and a similar learning rule has been proposed for modelling basal ganglia function
tactile-servoing-2d-dobot
No full textTactile data, pose models and servo control data from paper: DigiTac: A DIGIT-TacTip Hybrid Tactile Sensor for Comparing Low-Cost High-Resolution Robot Touch. N Lepora, Y Lin, B Money-Coomes, J Lloyd (2022) IEEE Robotics & Automation Letters. https://arxiv.org/abs/2206.13657.pd
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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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