2,583 research outputs found
Ethyl 3-[2-(p-toluenesulfonamido)phenyl]acrylate
In the title compound, C18H19NO4S, the two benzene rings form a dihedral angle of 52.2 (7)°. The crystal struture is stabilized by N—H⋯O hydrogen bonds, which link the molecules into dimers
Locate QCD Critical End Point in a Continuum Model Study
With a modified chemical potential dependent effective model for the gluon
propagator, we try to locate the critical end point (CEP) of strongly
interacting matter in the framework of Dyson-Schwinger equations (DSE). Beyond
the chiral limit, we find that Nambu solution and Wigner solution could coexist
in some area. Using the CornwallJackiw-Tomboulis (CJT) effective action, we
show that these two phases are connected by a first order phase transition. We
then locate CEP as the end point of the first order phase transition line.
Meanwhile, based on CJT effective action, we give a direct calculation for the
chiral susceptibility and thereby study the crossover.Comment: 9 pages, 7 figures; Version published in JHE
The Wigner Solution and QCD Phase Transitions in a Modified PNJL Model
By employing some modification to the widely used two-flavor Polyakov-loop
extended Nambu-Jona-Lasinio (PNJL) model, we discuss the Wigner solution of the
quark gap equation at finite temperature and zero quark chemical potential
beyond the chiral limit, and then try to explore its influences on the chiral
and deconfinement phase transitions of QCD at finite temperature and zero
chemical potential. The discovery of the coexistence of the Nambu and the
Wigner solutions of the quark gap equation with nonzero current quark mass at
zero temperature and zero chemical potential, as well as their evolutions with
temperature is very interesting for the studies of the phase transitions of
QCD. According to our results, the chiral phase transition might be of first
order (while the deconfinement phase transition is still a crossover, as in the
normal PNJL model), and the corresponding phase transition temperature is lower
than that of the deconfinement phase transition, instead of coinciding with
each other, which are not the same as the conclusions obtained from the normal
PNJL model. In addition, we also discuss the sensibility of our final results
on the choice of model parameters
Lifelong Sequential Modeling with Personalized Memorization for User Response Prediction
User response prediction, which models the user preference w.r.t. the
presented items, plays a key role in online services. With two-decade rapid
development, nowadays the cumulated user behavior sequences on mature Internet
service platforms have become extremely long since the user's first
registration. Each user not only has intrinsic tastes, but also keeps changing
her personal interests during lifetime. Hence, it is challenging to handle such
lifelong sequential modeling for each individual user. Existing methodologies
for sequential modeling are only capable of dealing with relatively recent user
behaviors, which leaves huge space for modeling long-term especially lifelong
sequential patterns to facilitate user modeling. Moreover, one user's behavior
may be accounted for various previous behaviors within her whole online
activity history, i.e., long-term dependency with multi-scale sequential
patterns. In order to tackle these challenges, in this paper, we propose a
Hierarchical Periodic Memory Network for lifelong sequential modeling with
personalized memorization of sequential patterns for each user. The model also
adopts a hierarchical and periodical updating mechanism to capture multi-scale
sequential patterns of user interests while supporting the evolving user
behavior logs. The experimental results over three large-scale real-world
datasets have demonstrated the advantages of our proposed model with
significant improvement in user response prediction performance against the
state-of-the-arts.Comment: SIGIR 2019. Reproducible codes and datasets:
https://github.com/alimamarankgroup/HPM
A Sparsity-Based InSAR Phase Denoising Algorithm Using Nonlocal Wavelet Shrinkage
An interferometric synthetic aperture radar (InSAR) phase denoising algorithm using the local sparsity of wavelet coefficients and nonlocal similarity of grouped blocks was developed. From the Bayesian perspective, the double-l1 norm regularization model that enforces the local and nonlocal sparsity constraints was used. Taking advantages of coefficients of the nonlocal similarity between group blocks for the wavelet shrinkage, the proposed algorithm effectively filtered the phase noise. Applying the method to simulated and acquired InSAR data, we obtained satisfactory results. In comparison, the algorithm outperformed several widely-used InSAR phase denoising approaches in terms of the number of residues, root-mean-square errors and other edge preservation indexes
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