3,398 research outputs found
Existence and Uniqueness for the Multivariate Discrete Terminal Wealth Relative
In this paper the multivariate fractional trading ansatz of money management
from Ralph Vince (Portfolio Management Formulas: Mathematical Trading Methods
for the Futures, Options, and Stock Markets, John Wiley & Sons, Inc., 1990) is
discussed. In particular, we prove existence and uniqueness of an optimal f of
the respective optimization problem under reasonable assumptions on the trade
return matrix. This result generalizes a similar result for the univariate
fractional trading ansatz. Furthermore, our result guarantees that the
multivariate optimal f solutions can always be found numerically by steepest
ascent methods
Confidence-aware Levenberg-Marquardt optimization for joint motion estimation and super-resolution
Motion estimation across low-resolution frames and the reconstruction of
high-resolution images are two coupled subproblems of multi-frame
super-resolution. This paper introduces a new joint optimization approach for
motion estimation and image reconstruction to address this interdependence. Our
method is formulated via non-linear least squares optimization and combines two
principles of robust super-resolution. First, to enhance the robustness of the
joint estimation, we propose a confidence-aware energy minimization framework
augmented with sparse regularization. Second, we develop a tailor-made
Levenberg-Marquardt iteration scheme to jointly estimate motion parameters and
the high-resolution image along with the corresponding model confidence
parameters. Our experiments on simulated and real images confirm that the
proposed approach outperforms decoupled motion estimation and image
reconstruction as well as related state-of-the-art joint estimation algorithms.Comment: accepted for ICIP 201
Dynamical response of ultracold interacting fermion-boson mixtures
We analyze the dynamical response of a ultracold binary gas mixture in
presence of strong boson-fermion couplings. Mapping the problem onto that of
the optical response of a metal/semiconductor electronic degrees of freedom to
electromagnetic perturbation we calculate the corresponding dynamic linear
response susceptibility in the non-perturbative regimes of strong boson-fermion
coupling using diagrammatic resummation technique as well as quantum Monte
Carlo simulations. We evaluate the Bragg spectral function as well as the
optical conductivity and find a pseudogap, which forms in certain parameter
regimes.Comment: 32 pages, 13 figure
SkinNet: A Deep Learning Framework for Skin Lesion Segmentation
There has been a steady increase in the incidence of skin cancer worldwide,
with a high rate of mortality. Early detection and segmentation of skin lesions
are crucial for timely diagnosis and treatment, necessary to improve the
survival rate of patients. However, skin lesion segmentation is a challenging
task due to the low contrast of lesions and their high similarity in terms of
appearance, to healthy tissue. This underlines the need for an accurate and
automatic approach for skin lesion segmentation. To tackle this issue, we
propose a convolutional neural network (CNN) called SkinNet. The proposed CNN
is a modified version of U-Net. We compared the performance of our approach
with other state-of-the-art techniques, using the ISBI 2017 challenge dataset.
Our approach outperformed the others in terms of the Dice coefficient, Jaccard
index and sensitivity, evaluated on the held-out challenge test data set,
across 5-fold cross validation experiments. SkinNet achieved an average value
of 85.10, 76.67 and 93.0%, for the DC, JI, and SE, respectively.Comment: 2 pages, submitted to NSS/MIC 201
Empirical Study of the 1-2-3 Trend Indicator
In this paper we study automatically recognized trends and investigate their
statistics. To do that we introduce the notion of a wavelength for time series
via cross correlation and use this wavelength to calibrate the 1-2-3 trend
indicator of Maier-Paape [Automatic One Two Three, Quantitative Finance, 2013]
to automatically find trends. Extensive statistics are reported for EUR-USD,
DAX-Future, Gold and Crude Oil regarding e.g. the dynamic, duration and
extension of trends on different time scales.Comment: 21 pages, 13 figures, 5 tables; Keywords: market technical trends,
automatic trend analysis, wavelength of time series, autocorrelatio
Functional renormalization group for commensurate antiferromagnets: Beyond the mean-field picture
We present a functional renormalization group (fRG) formalism for interacting
fermions on lattices that captures the flow into states with commensurate
spin-density wave order. During the flow, the growth of the order parameter is
fed back into the flow of the interactions and all modes can be integrated out.
This extends previous fRG flows in the symmetric phase that run into a
divergence at a nonzero RG scale, i.e., that have to be stopped at the ordering
scale. We use the corresponding Ward identity to check the accuracy of the
results. We apply our new method to a model with two Fermi pockets that have
perfect particle-hole nesting. The results obtained from the fRG are compared
with those in random phase approximation.Comment: revised version; 24 pages, 12 figure
Willensfreiheit als Selbstbestimmung : Michael Pauens kompatibilistische Theorie der Freiheit
Rezension zu: Michael Pauen : Illusion Freiheit? Mögliche und unmögliche Konsequenzen der Hirnforschung, S. Fischer Verlag, Frankfurt, 2004, ISBN 3-10-061910-2, 276 Seiten, 19,90 Euro
Higgs effects in top anti-top production near threshold in e+ e- annihilation
The completion of the third-order QCD corrections to the inclusive top-pair
production cross section near threshold demonstrates that the strong dynamics
is under control at the few percent level. In this paper we consider the
effects of the Higgs boson on the cross section and, for the first time,
combine the third-order QCD result with the third-order P-wave, the leading QED
and the leading non-resonant contributions. We study the size of the different
effects and investigate the sensitivity of the cross section to variations of
the top-quark Yukawa coupling due to possible new physics effects.Comment: LaTeX, 17 page
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