24,281 research outputs found
VideoCapsuleNet: A Simplified Network for Action Detection
The recent advances in Deep Convolutional Neural Networks (DCNNs) have shown
extremely good results for video human action classification, however, action
detection is still a challenging problem. The current action detection
approaches follow a complex pipeline which involves multiple tasks such as tube
proposals, optical flow, and tube classification. In this work, we present a
more elegant solution for action detection based on the recently developed
capsule network. We propose a 3D capsule network for videos, called
VideoCapsuleNet: a unified network for action detection which can jointly
perform pixel-wise action segmentation along with action classification. The
proposed network is a generalization of capsule network from 2D to 3D, which
takes a sequence of video frames as input. The 3D generalization drastically
increases the number of capsules in the network, making capsule routing
computationally expensive. We introduce capsule-pooling in the convolutional
capsule layer to address this issue which makes the voting algorithm tractable.
The routing-by-agreement in the network inherently models the action
representations and various action characteristics are captured by the
predicted capsules. This inspired us to utilize the capsules for action
localization and the class-specific capsules predicted by the network are used
to determine a pixel-wise localization of actions. The localization is further
improved by parameterized skip connections with the convolutional capsule
layers and the network is trained end-to-end with a classification as well as
localization loss. The proposed network achieves sate-of-the-art performance on
multiple action detection datasets including UCF-Sports, J-HMDB, and UCF-101
(24 classes) with an impressive ~20% improvement on UCF-101 and ~15%
improvement on J-HMDB in terms of v-mAP scores
Complex order control for improved loop-shaping in precision positioning
This paper presents a complex order filter developed and subsequently
integrated into a PID-based controller design. The nonlinear filter is designed
with reset elements to have describing function based frequency response
similar to that of a linear (practically non-implementable) complex order
filter. This allows for a design which has a negative gain slope and a
corresponding positive phase slope as desired from a loop-shaping
controller-design perspective. This approach enables improvement in precision
tracking without compromising the bandwidth or stability requirements. The
proposed designs are tested on a planar precision positioning stage and
performance compared with PID and other state-of-the-art reset based
controllers to showcase the advantages of this filter
A unification in the theory of linearization of second order nonlinear ordinary differential equations
In this letter, we introduce a new generalized linearizing transformation
(GLT) for second order nonlinear ordinary differential equations (SNODEs). The
well known invertible point (IPT) and non-point transformations (NPT) can be
derived as sub-cases of the GLT. A wider class of nonlinear ODEs that cannot be
linearized through NPT and IPT can be linearized by this GLT. We also
illustrate how to construct GLTs and to identify the form of the linearizable
equations and propose a procedure to derive the general solution from this GLT
for the SNODEs. We demonstrate the theory with two examples which are of
contemporary interest.Comment: 8 page
The mass and environmental dependence on the secular processes of AGN in terms of morphology, colour, and specific star-formation rate
Galaxy mass and environment play a major role in the evolution of galaxies.
In the transition from star-forming to quenched galaxies, Active galactic
nuclei (AGN) have also a principal action. However, the connections between
these three actors are still uncertain. In this work we investigate the effects
of stellar mass and the large-scale environment (LSS), on the fraction of
optical nuclear activity in a population of isolated galaxies, where AGN would
not be triggered by recent galaxy interactions or mergers. As a continuation of
a previous work, we focus on isolated galaxies to study the effect of stellar
mass and the LSS in terms of morphology (early- and late-type), colour (red and
blue), and specific star formation rate (quenched and star-forming). To explore
where AGN activity is affected by the LSS we fix the stellar mass into low- and
high-mass galaxies. We use the tidal strength parameter to quantify their
effects. We found that AGN is strongly affected by stellar mass in 'active'
galaxies (namely late-type, blue, and star-forming), however it has no
influence for 'quiescent' galaxies (namely early-type, red, and quenched), at
least for masses down to . In relation to the LSS, we
found an increment on the fraction of SFN with denser LSS in low-mass star
forming and red isolated galaxies. Regarding AGN, we find a clear increment of
the fraction of AGN with denser environment in quenched and red isolated
galaxies, independently of the stellar mass. AGN activity would be 'mass
triggered' in 'active' isolated galaxies. This means that AGN is independent of
the intrinsic property of the galaxies, but on its stellar mass. On the other
hand, AGN would be 'environment triggered' in 'quiescent' isolated galaxies,
where the fraction of AGN in terms of sSFR and colour increases from void
regions to denser LSS, independently of its stellar mass.Comment: 14 pages, 9 figures (11 pages and 6 figures without appendix),
accepted for publication in Astronomy & Astrophysic
A Method to Tackle First Order Differential Equations with Liouvillian Functions in the Solution - II
We present a semi-decision procedure to tackle first order differential
equations, with Liouvillian functions in the solution (LFOODEs). As in the case
of the Prelle-Singer procedure, this method is based on the knowledge of the
integrating factor structure.Comment: 11 pages, late
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