31,762 research outputs found
An extension of min/max flow framework
In this paper, the min/max flow scheme for image restoration is revised. The novelty consists of the fol-
24 lowing three parts. The first is to analyze the reason of the speckle generation and then to modify the
25 original scheme. The second is to point out that the continued application of this scheme cannot result
26 in an adaptive stopping of the curvature flow. This is followed by modifications of the original scheme
27 through the introduction of the Gradient Vector Flow (GVF) field and the zero-crossing detector, so as
28 to control the smoothing effect. Our experimental results with image restoration show that the proposed
29 schemes can reach a steady state solution while preserving the essential structures of objects. The third is
30 to extend the min/max flow scheme to deal with the boundary leaking problem, which is indeed an
31 intrinsic shortcoming of the familiar geodesic active contour model. The min/max flow framework pro-
32 vides us with an effective way to approximate the optimal solution. From an implementation point of
33 view, this extended scheme makes the speed function simpler and more flexible. The experimental
34 results of segmentation and region tracking show that the boundary leaking problem can be effectively
35 suppressed
Indirect Searches of the Degenerate MSSM
A degenerate sfermionic particle spectrum can escape constraints from flavor
physics, and at the same time evade the limits from the direct searches if the
degeneracy extends to the gaugino-higgsino sector. Inspired by this, we
consider a scenario where all the soft terms have an approximately common mass
scale at , with splittings . As a
result, the third generation sfermions have large to maximal (left-right)
mixing, the same being the case with charginos and some sectors of the
neutralino mass matrix. We study this scenario in the light of discovery of the
Higgs boson with mass 125 GeV. We consider constraints from -physics,
the anomalous magnetic moment of the muon and the dark matter relic density. We
find that a supersymmetric spectrum as light as 600 GeV could be consistent
with all current data and also account for the observed anomalous magnetic
moment of the muon within . The neutralino relic density is generally
too small to saturate the measured cold dark matter relic density. Direct
detection limits from XENON100 and LUX put severe constraints on this scenario
which will be conclusively probed by XENONnT experiment.Comment: 27 pages, 8 figures; Comments welcom
Quickest Change Detection of a Markov Process Across a Sensor Array
Recent attention in quickest change detection in the multi-sensor setting has
been on the case where the densities of the observations change at the same
instant at all the sensors due to the disruption. In this work, a more general
scenario is considered where the change propagates across the sensors, and its
propagation can be modeled as a Markov process. A centralized, Bayesian version
of this problem, with a fusion center that has perfect information about the
observations and a priori knowledge of the statistics of the change process, is
considered. The problem of minimizing the average detection delay subject to
false alarm constraints is formulated as a partially observable Markov decision
process (POMDP). Insights into the structure of the optimal stopping rule are
presented. In the limiting case of rare disruptions, we show that the structure
of the optimal test reduces to thresholding the a posteriori probability of the
hypothesis that no change has happened. We establish the asymptotic optimality
(in the vanishing false alarm probability regime) of this threshold test under
a certain condition on the Kullback-Leibler (K-L) divergence between the post-
and the pre-change densities. In the special case of near-instantaneous change
propagation across the sensors, this condition reduces to the mild condition
that the K-L divergence be positive. Numerical studies show that this low
complexity threshold test results in a substantial improvement in performance
over naive tests such as a single-sensor test or a test that wrongly assumes
that the change propagates instantaneously.Comment: 40 pages, 5 figures, Submitted to IEEE Trans. Inform. Theor
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