446 research outputs found
Teleoperator systems for manned space missions
The development of remote mechanical systems to augment man's capabilities in our manned space effort is considered. A teleoperator system extends man's innate intelligence and sensory capabilities to distant hostile and hazardous environments through a manipulator-equipped spacecraft and an RF link. Examined are space teleoperator system applications in the space station/space shuttle program, which is where the most immediate need exists and the potential return is greatest
A political radicalization framework based on Moral Foundations Theory
Moral Foundations Theory proposes that individuals with conflicting political
views base their behavior on different principles chosen from a small group of
universal moral foundations. This study proposes using a set of widely accepted
moral foundations (Fairness, Ingroup loyalty, Authority, and Purity) as proxies
to determine the degree of radicalization of online communities. The fifth
principle, Care, is generally surpassed by others, which are higher in the
radicalized groups' moral hierarchy. Moreover, the presented data-driven
methodological framework proposes an alternative way to measure whether a
community complies with some moral principle or foundation: not evaluating its
speech, but its behavior through interactions of its individuals, establishing
a bridge between structural features of the interaction network and the
intensity of communities' radicalization regarding the considered moral
foundations. Two foundations may be assessed using the network's structural
characteristics: Ingroup loyalty measured by group-level modularity, and
Authority evaluated using group domination for detecting potential hierarchical
substructures within the network. By analyzing the set of Pareto-optimal groups
regarding a multidimensional moral relevance scale, the most radicalized
communities are identified among those considered extreme in some of their
attitudes or views. The application of the proposed framework is illustrated
using real-world datasets. The radicalized communities' behavior exhibits
increasing isolation, and its authorities and leaders show growing domination
over their audience. There were also detected differences between users'
behavior and speech, showing that individuals tend to share more 'extreme'
ingroup content than that they publish: extreme views get more likes on social
media
Expert-Augmented Machine Learning
Machine Learning is proving invaluable across disciplines. However, its
success is often limited by the quality and quantity of available data, while
its adoption by the level of trust that models afford users. Human vs. machine
performance is commonly compared empirically to decide whether a certain task
should be performed by a computer or an expert. In reality, the optimal
learning strategy may involve combining the complementary strengths of man and
machine. Here we present Expert-Augmented Machine Learning (EAML), an automated
method that guides the extraction of expert knowledge and its integration into
machine-learned models. We use a large dataset of intensive care patient data
to predict mortality and show that we can extract expert knowledge using an
online platform, help reveal hidden confounders, improve generalizability on a
different population and learn using less data. EAML presents a novel framework
for high performance and dependable machine learning in critical applications
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Expert-augmented machine learning.
Machine learning is proving invaluable across disciplines. However, its success is often limited by the quality and quantity of available data, while its adoption is limited by the level of trust afforded by given models. Human vs. machine performance is commonly compared empirically to decide whether a certain task should be performed by a computer or an expert. In reality, the optimal learning strategy may involve combining the complementary strengths of humans and machines. Here, we present expert-augmented machine learning (EAML), an automated method that guides the extraction of expert knowledge and its integration into machine-learned models. We used a large dataset of intensive-care patient data to derive 126 decision rules that predict hospital mortality. Using an online platform, we asked 15 clinicians to assess the relative risk of the subpopulation defined by each rule compared to the total sample. We compared the clinician-assessed risk to the empirical risk and found that, while clinicians agreed with the data in most cases, there were notable exceptions where they overestimated or underestimated the true risk. Studying the rules with greatest disagreement, we identified problems with the training data, including one miscoded variable and one hidden confounder. Filtering the rules based on the extent of disagreement between clinician-assessed risk and empirical risk, we improved performance on out-of-sample data and were able to train with less data. EAML provides a platform for automated creation of problem-specific priors, which help build robust and dependable machine-learning models in critical applications
Learning Interpretable Heuristics for WalkSAT
Local search algorithms are well-known methods for solving large, hard instances of the satisfiability problem (SAT). The performance of these algorithms crucially depends on heuristics for setting noise parameters and scoring variables. The optimal setting for these heuristics varies for different instance distributions. In this paper, we present an approach for learning effective variable scoring functions and noise parameters by using reinforcement learning. We consider satisfiability problems from different instance distributions and learn specialized heuristics for each of them. Our experimental results show improvements with respect to both a WalkSAT baseline and another local search learned heuristic
Group polarization, influence, and domination in online interaction networks: A case study of the 2022 Brazilian elections
In this work, we investigate the evolution of polarization, influence, and
domination in online interaction networks. Twitter data collected before and
during the 2022 Brazilian elections is used as a case study. From a theoretical
perspective, we develop a methodology called d-modularity that allows
discovering the contribution of specific groups to network polarization using
the well-known modularity measure. While the overall network modularity
(somewhat unexpectedly) decreased, the proposed group-oriented approach allows
concluding that the contribution of the right-leaning community to this
modularity increased, remaining very high during the analyzed period. Our
methodology is general enough to be used in any situation when the contribution
of specific groups to overall network modularity and polarization is needed to
investigate. Moreover, using the concept of partial domination, we are able to
compare the reach of sets of influential profiles from different groups and
their ability to accomplish coordinated communication inside their groups and
across segments of the entire network during some specific time window. We show
that in the whole network, the left-leaning high-influential information
spreaders dominated, reaching a substantial fraction of users with fewer
spreaders. However, when comparing domination inside the groups, the results
are inverse. Right-leaning spreaders dominate their communities using few
nodes, showing as the most capable of accomplishing coordinated communication.
The results bring evidence of extreme isolation and the ease of accomplishing
coordinated communication that characterized right-leaning communities during
the 2022 Brazilian elections
A practical introduction to using the drift diffusion model of decision-making in cognitive psychology, neuroscience, and health sciences
Recent years have seen a rapid increase in the number of studies using evidence-accumulation models (such as the drift diffusion model, DDM) in the fields of psychology and neuroscience. These models go beyond observed behavior to extract descriptions of latent cognitive processes that have been linked to different brain substrates. Accordingly, it is important for psychology and neuroscience researchers to be able to understand published findings based on these models. However, many articles using (and explaining) these models assume that the reader already has a fairly deep understanding of (and interest in) the computational and mathematical underpinnings, which may limit many readers’ ability to understand the results and appreciate the implications. The goal of this article is therefore to provide a practical introduction to the DDM and its application to behavioral data – without requiring a deep background in mathematics or computational modeling. The article discusses the basic ideas underpinning the DDM, and explains the way that DDM results are normally presented and evaluated. It also provides a step-by-step example of how the DDM is implemented and used on an example dataset, and discusses methods for model validation and for presenting (and evaluating) model results. Supplementary material provides R code for all examples, along with the sample dataset described in the text, to allow interested readers to replicate the examples themselves. The article is primarily targeted at psychologists, neuroscientists, and health professionals with a background in experimental cognitive psychology and/or cognitive neuroscience, who are interested in understanding how DDMs are used in the literature, as well as some who may to go on to apply these approaches in their own work.</p
Catching a Viral Video
The sharing and re-sharing of videos on social sites, blogs e-mail, and other means has given rise to the phenomenon of viral videos - videos that become popular through internet sharing. In this paper we seek to better understand viral videos on YouTube by analyzing sharing and its relationship to video popularity using millions of YouTube videos. The socialness of a video is quantified by classifying the referrer sources for video views as social (e.g. an emailed link, Facebook referral) or non-social (e.g. a link from related videos). We find that viewership patterns of highly social videos are very different from less social videos. For example, the highly social videos rise to, and fall from, their peak popularity more quickly than less social videos. We also find that not all highly social videos become popular, and not all popular videos are highly social. By using our insights on viral videos we are able develop a method for ranking blogs and websites on their ability to spread viral videos
La construcción de la identidad cultural en jóvenes mayas de Kopchen, Quintana Roo
La identidad cultural de un pueblo emerge desde las experiencias históricas y culturales que viven, adquieren y comparten los miembros del colectivo (comunidad), y que con el paso del tiempo forjan un sentimiento de pertenencia enraizado en múltiples aspectos de la cultura. Hablar de identidad cultural es referir a un proceso dinámico de construcción y reconstrucción. La presente investigación refiere a la construcción de las identidades culturales de las y los jóvenes de origen étnico maya residentes de una comunidad indígena, a partir de la penetración de los medios globales en espacios sociales cotidianos para los jóvenes, como la escuela telesecundaria principalmente y la comunidad. El trabajo se realizó con base en una metodología de tipo cualitativo, y para el cumplimiento de los objetivos de la investigación se implementó el método de estudio de caso descriptivo. Los principales resultados del análisis de información mostraron que el uso de los medios globales de comunicación tanto en la escuela y la comunidad incide significativamente en las identidades culturales de los jóvenes mayas, principalmente en la forma de percibir la realidad cultural que viven. Los resultados son importantes, ya que forjan la base para una investigación con más profundidad, siendo el primer trabajo documentado en la región y de la comunidad sobre dicha problemática
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