403,131 research outputs found
Machine Learning for Neuroimaging with Scikit-Learn
Statistical machine learning methods are increasingly used for neuroimaging
data analysis. Their main virtue is their ability to model high-dimensional
datasets, e.g. multivariate analysis of activation images or resting-state time
series. Supervised learning is typically used in decoding or encoding settings
to relate brain images to behavioral or clinical observations, while
unsupervised learning can uncover hidden structures in sets of images (e.g.
resting state functional MRI) or find sub-populations in large cohorts. By
considering different functional neuroimaging applications, we illustrate how
scikit-learn, a Python machine learning library, can be used to perform some
key analysis steps. Scikit-learn contains a very large set of statistical
learning algorithms, both supervised and unsupervised, and its application to
neuroimaging data provides a versatile tool to study the brain.Comment: Frontiers in neuroscience, Frontiers Research Foundation, 2013, pp.1
Curiosity cloning: neural analysis of scientific knowledge
Event-related potentials (ERPs) are indicators of brain
activity related to cognitive processes. They can be de-
tected from EEG signals and thus constitute an attractive
non-invasive option to study cognitive information pro-
cessing. The P300 wave is probably the most celebrated
example of an event-related potential and it is classically
studied in connection to the odd-ball paradigm experi-
mental protocol, able to consistently provoke the brain
wave. We propose the use of P300 detection to identify
the scientific interest in a large set of images and train
a computer with machine learning algorithms using the
subject’s responses to the stimuli as the training data set. As a first step, we here describe a number of experiments designed to relate the P300 brain wave to the cognitive processes related to placing a scientific judgment on a picture and to study the number of images per seconds
that can be processed by such a system
Representation Learning by Learning to Count
We introduce a novel method for representation learning that uses an
artificial supervision signal based on counting visual primitives. This
supervision signal is obtained from an equivariance relation, which does not
require any manual annotation. We relate transformations of images to
transformations of the representations. More specifically, we look for the
representation that satisfies such relation rather than the transformations
that match a given representation. In this paper, we use two image
transformations in the context of counting: scaling and tiling. The first
transformation exploits the fact that the number of visual primitives should be
invariant to scale. The second transformation allows us to equate the total
number of visual primitives in each tile to that in the whole image. These two
transformations are combined in one constraint and used to train a neural
network with a contrastive loss. The proposed task produces representations
that perform on par or exceed the state of the art in transfer learning
benchmarks.Comment: ICCV 2017(oral
Sun as a Star: Science Learning Activities for Afterschool
This educator's guide features eight activities in which younger students use brainstorming, observations, and experiments to learn about the Sun. They will begin by learning that light is our means of studying the Sun, use spectroscopes to separate white light into its component colors, and learn that there are other forms of light outside the visible spectrum. Then the students will conduct experiments to learn how light travels and set up an outdoor investigation to find out how the size and position of shadows relate to the position of the Sun in the sky. In the final activities, they will construct a model to simulate the motion of the Sun relative to the Earth, view satellite images taken by the SOHO satellite, and extend their knowledge of the Sun as a star by observing images of stars and recording their ideas on whether all stars are like the Sun. Educational levels: Primary elementary, Intermediate elementary, Middle school
The Shape of Art History in the Eyes of the Machine
How does the machine classify styles in art? And how does it relate to art
historians' methods for analyzing style? Several studies have shown the ability
of the machine to learn and predict style categories, such as Renaissance,
Baroque, Impressionism, etc., from images of paintings. This implies that the
machine can learn an internal representation encoding discriminative features
through its visual analysis. However, such a representation is not necessarily
interpretable. We conducted a comprehensive study of several of the
state-of-the-art convolutional neural networks applied to the task of style
classification on 77K images of paintings, and analyzed the learned
representation through correlation analysis with concepts derived from art
history. Surprisingly, the networks could place the works of art in a smooth
temporal arrangement mainly based on learning style labels, without any a
priori knowledge of time of creation, the historical time and context of
styles, or relations between styles. The learned representations showed that
there are few underlying factors that explain the visual variations of style in
art. Some of these factors were found to correlate with style patterns
suggested by Heinrich W\"olfflin (1846-1945). The learned representations also
consistently highlighted certain artists as the extreme distinctive
representative of their styles, which quantitatively confirms art historian
observations
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