7,896 research outputs found
Unsupervised Understanding of Location and Illumination Changes in Egocentric Videos
Wearable cameras stand out as one of the most promising devices for the
upcoming years, and as a consequence, the demand of computer algorithms to
automatically understand the videos recorded with them is increasing quickly.
An automatic understanding of these videos is not an easy task, and its mobile
nature implies important challenges to be faced, such as the changing light
conditions and the unrestricted locations recorded. This paper proposes an
unsupervised strategy based on global features and manifold learning to endow
wearable cameras with contextual information regarding the light conditions and
the location captured. Results show that non-linear manifold methods can
capture contextual patterns from global features without compromising large
computational resources. The proposed strategy is used, as an application case,
as a switching mechanism to improve the hand-detection problem in egocentric
videos.Comment: Submitted for publicatio
Evolution of Complexity in Out-of-Equilibrium Systems by Time-Resolved or Space-Resolved Synchrotron Radiation Techniques
Out-of-equilibrium phenomena are attracting high interest in physics,
materials science, chemistry and life sciences. In this state, the study of
structural fluctuations at different length scales in time and space are
necessary to achieve significant advances in the understanding of
structure-functionality relationship. The visualization of patterns arising
from spatiotemporal fluctuations is nowadays possible thanks to new advances in
X-ray instrumentation development that combine high resolution both in space
and in time. We present novel experimental approaches using high brilliance
synchrotron radiation sources, fast detectors and focusing optics, joint with
advanced data analysis based on automated statistical, mathematical and imaging
processing tools. This approach has been used to investigate structural
fluctuations in out-of-equilibrium systems in the novel field of inhomogeneous
quantum complex matter at the crossing point of technology, physics and
biology. In particular, we discuss how nanoscale complexity controls the
emergence of high temperature superconductivity (HTS), myelin functionality and
formation of hybrid organic-inorganic nanostructures. The emergent complex
geometries, opening novel venues to quantum technology and to development of
quantum physics of living systems, are discussedComment: 18 pages, 7 figure
Optimizing an Organized Modularity Measure for Topographic Graph Clustering: a Deterministic Annealing Approach
This paper proposes an organized generalization of Newman and Girvan's
modularity measure for graph clustering. Optimized via a deterministic
annealing scheme, this measure produces topologically ordered graph clusterings
that lead to faithful and readable graph representations based on clustering
induced graphs. Topographic graph clustering provides an alternative to more
classical solutions in which a standard graph clustering method is applied to
build a simpler graph that is then represented with a graph layout algorithm. A
comparative study on four real world graphs ranging from 34 to 1 133 vertices
shows the interest of the proposed approach with respect to classical solutions
and to self-organizing maps for graphs
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