11,257 research outputs found
A New Biometric Template Protection using Random Orthonormal Projection and Fuzzy Commitment
Biometric template protection is one of most essential parts in putting a
biometric-based authentication system into practice. There have been many
researches proposing different solutions to secure biometric templates of
users. They can be categorized into two approaches: feature transformation and
biometric cryptosystem. However, no one single template protection approach can
satisfy all the requirements of a secure biometric-based authentication system.
In this work, we will propose a novel hybrid biometric template protection
which takes benefits of both approaches while preventing their limitations. The
experiments demonstrate that the performance of the system can be maintained
with the support of a new random orthonormal project technique, which reduces
the computational complexity while preserving the accuracy. Meanwhile, the
security of biometric templates is guaranteed by employing fuzzy commitment
protocol.Comment: 11 pages, 6 figures, accepted for IMCOM 201
Effect of feedback on the control of a two-level dissipative quantum system
We show that it is possible to modify the stationary state by a feedback
control in a two-level dissipative quantum system. Based on the geometric
control theory, we also analyze the effect of the feedback on the time-optimal
control in the dissipative system governed by the Lindblad master equation.
These effects are reflected in the function and
that characterize the optimal trajectories, as well as the
switching function and which characterize the switching
point in time for the time-optimal trajectory.Comment: 5 pages, 5 figure
Frequency locking of modulated waves
We consider the behavior of a modulated wave solution to an
-equivariant autonomous system of differential equations under an
external forcing of modulated wave type. The modulation frequency of the
forcing is assumed to be close to the modulation frequency of the modulated
wave solution, while the wave frequency of the forcing is supposed to be far
from that of the modulated wave solution. We describe the domain in the
three-dimensional control parameter space (of frequencies and amplitude of the
forcing) where stable locking of the modulation frequencies of the forcing and
the modulated wave solution occurs.
Our system is a simplest case scenario for the behavior of self-pulsating
lasers under the influence of external periodically modulated optical signals
Radio Continuum and Star Formation in CO-rich Early Type Galaxies
In this paper we present new high resolution VLA 1.4 GHz radio continuum
observations of five FIR bright CO-rich early-type galaxies and two dwarf
early-type galaxies. The position on the radio-FIR correlation combined with
striking agreements in morphology between high resolution CO and radio maps
show that the radio continuum is associated with star formation in at least
four of the eight galaxies. The average star formation rate for the sample
galaxies detected in radio is approximately 2 solar masses per year. There is
no evidence of a luminous AGN in any of our sample galaxies. We estimate Toomre
Q values and find that the gas disks may well be gravitationally unstable,
consistent with the above evidence for star formation activity. The radio
continuum emission thus corroborates other recent suggestions that star
formation in early type galaxies may not be uncommon.Comment: 21 pages, 7 figures, to be published in the Astronomical Journa
Reduced dynamics with renormalization in solid-state charge qubit measurement
Quantum measurement will inevitably cause backaction on the measured system,
resulting in the well known dephasing and relaxation. In this report, in the
context of solid--state qubit measurement by a mesoscopic detector, we show
that an alternative backaction known as renormalization is important under some
circumstances. This effect is largely overlooked in the theory of quantum
measurement.Comment: 12 pages, 4 figure
Uniformly Accelerated Mirrors. Part 1: Mean Fluxes
The Davies-Fulling model describes the scattering of a massless field by a
moving mirror in 1+1 dimensions. When the mirror travels under uniform
acceleration, one encounters severe problems which are due to the infinite blue
shift effects associated with the horizons. On one hand, the Bogoliubov
coefficients are ill-defined and the total energy emitted diverges. On the
other hand, the instantaneous mean flux vanishes. To obtained well-defined
expressions we introduce an alternative model based on an action principle. The
usefulness of this model is to allow to switch on and off the interaction at
asymptotically large times. By an appropriate choice of the switching function,
we obtain analytical expressions for the scattering amplitudes and the fluxes
emitted by the mirror. When the coupling is constant, we recover the vanishing
flux. However it is now followed by transients which inevitably become singular
when the switching off is performed at late time. Our analysis reveals that the
scattering amplitudes (and the Bogoliubov coefficients) should be seen as
distributions and not as mere functions. Moreover, our regularized amplitudes
can be put in a one to one correspondence with the transition amplitudes of an
accelerated detector, thereby unifying the physics of uniformly accelerated
systems. In a forthcoming article, we shall use our scattering amplitudes to
analyze the quantum correlations amongst emitted particles which are also
ill-defined in the Davies-Fulling model in the presence of horizons.Comment: 23 pages, 7 postscript figure
Towards a Notion of Distributed Time for Petri Nets
We set the ground for research on a timed extension of Petri nets where time parameters are associated with tokens and arcs carry constraints that qualify the age of tokens required for enabling. The novelty is that, rather than a single global clock, we use a set of unrelated clocks --- possibly one per place --- allowing a local timing as well as distributed time synchronisation. We give a formal definition of the model and investigate properties of local versus global timing, including decidability issues and notions of processes of the respective models
Pairwise covariance adds little to secondary structure prediction but improves the prediction of non-canonical local structure
<p>Abstract</p> <p>Background</p> <p>Amino acid sequence probability distributions, or profiles, have been used successfully to predict secondary structure and local structure in proteins. Profile models assume the statistical independence of each position in the sequence, but the energetics of protein folding is better captured in a scoring function that is based on pairwise interactions, like a force field.</p> <p>Results</p> <p>I-sites motifs are short sequence/structure motifs that populate the protein structure database due to energy-driven convergent evolution. Here we show that a pairwise covariant sequence model does not predict alpha helix or beta strand significantly better overall than a profile-based model, but it does improve the prediction of certain loop motifs. The finding is best explained by considering secondary structure profiles as multivariant, all-or-none models, which subsume covariant models. Pairwise covariance is nonetheless present and energetically rational. Examples of negative design are present, where the covariances disfavor non-native structures.</p> <p>Conclusion</p> <p>Measured pairwise covariances are shown to be statistically robust in cross-validation tests, as long as the amino acid alphabet is reduced to nine classes. An updated I-sites local structure motif library that provides sequence covariance information for all types of local structure in globular proteins and a web server for local structure prediction are available at <url>http://www.bioinfo.rpi.edu/bystrc/hmmstr/server.php</url>.</p
Boundary-RL: Reinforcement Learning for Weakly-Supervised Prostate Segmentation in TRUS Images
We propose Boundary-RL, a novel weakly supervised segmentation method that
utilises only patch-level labels for training. We envision the segmentation as
a boundary detection problem, rather than a pixel-level classification as in
previous works. This outlook on segmentation may allow for boundary delineation
under challenging scenarios such as where noise artefacts may be present within
the region-of-interest (ROI) boundaries, where traditional pixel-level
classification-based weakly supervised methods may not be able to effectively
segment the ROI. Particularly of interest, ultrasound images, where intensity
values represent acoustic impedance differences between boundaries, may also
benefit from the boundary delineation approach. Our method uses reinforcement
learning to train a controller function to localise boundaries of ROIs using a
reward derived from a pre-trained boundary-presence classifier. The classifier
indicates when an object boundary is encountered within a patch, as the
controller modifies the patch location in a sequential Markov decision process.
The classifier itself is trained using only binary patch-level labels of object
presence, which are the only labels used during training of the entire boundary
delineation framework, and serves as a weak signal to inform the boundary
delineation. The use of a controller function ensures that a sliding window
over the entire image is not necessary. It also prevents possible
false-positive or -negative cases by minimising number of patches passed to the
boundary-presence classifier. We evaluate our proposed approach for a
clinically relevant task of prostate gland segmentation on trans-rectal
ultrasound images. We show improved performance compared to other tested weakly
supervised methods, using the same labels e.g., multiple instance learning.Comment: Accepted to MICCAI Workshop MLMI 2023 (14th International Conference
on Machine Learning in Medical Imaging
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