24,693 research outputs found
Nondiffractive feature of with -meson electromagnetic multipole moments
We investigate photoproduction of charged off the nucleon using
Regge pole exchanges by considering the -meson
electromagnetic multipole moments. The significance of the Ward identity at the
vertex is emphasized for current conservation in the process.
Given exchange with the well-known coupling constants for
and , we analyze the role of the exchange in the and processes without model-dependences except
for the magnetic moment and electric quadrupole moment
fm taken from theoretical estimates. The
nondiffractive feature of both cross sections is reproduced with a rapid
decrease beyond the resonance region by the dominance of exchange over
the \,. % Cross sections for differential and density matrix elements are
presented to compare with existing data. The parity and photon polarization
asymmetries are predicted to demonstrate the apparent roles of the -meson
electromagnetic multipole moments.Comment: 5 pages, 8 figure
An Alternative Approach to Functional Linear Partial Quantile Regression
We have previously proposed the partial quantile regression (PQR) prediction
procedure for functional linear model by using partial quantile covariance
techniques and developed the simple partial quantile regression (SIMPQR)
algorithm to efficiently extract PQR basis for estimating functional
coefficients. However, although the PQR approach is considered as an attractive
alternative to projections onto the principal component basis, there are
certain limitations to uncovering the corresponding asymptotic properties
mainly because of its iterative nature and the non-differentiability of the
quantile loss function. In this article, we propose and implement an
alternative formulation of partial quantile regression (APQR) for functional
linear model by using block relaxation method and finite smoothing techniques.
The proposed reformulation leads to insightful results and motivates new
theory, demonstrating consistency and establishing convergence rates by
applying advanced techniques from empirical process theory. Two simulations and
two real data from ADHD-200 sample and ADNI are investigated to show the
superiority of our proposed methods
Predicting Social Links for New Users across Aligned Heterogeneous Social Networks
Online social networks have gained great success in recent years and many of
them involve multiple kinds of nodes and complex relationships. Among these
relationships, social links among users are of great importance. Many existing
link prediction methods focus on predicting social links that will appear in
the future among all users based upon a snapshot of the social network. In
real-world social networks, many new users are joining in the service every
day. Predicting links for new users are more important. Different from
conventional link prediction problems, link prediction for new users are more
challenging due to the following reasons: (1) differences in information
distributions between new users and the existing active users (i.e., old
users); (2) lack of information from the new users in the network. We propose a
link prediction method called SCAN-PS (Supervised Cross Aligned Networks link
prediction with Personalized Sampling), to solve the link prediction problem
for new users with information transferred from both the existing active users
in the target network and other source networks through aligned accounts. We
proposed a within-target-network personalized sampling method to process the
existing active users' information in order to accommodate the differences in
information distributions before the intra-network knowledge transfer. SCAN-PS
can also exploit information in other source networks, where the user accounts
are aligned with the target network. In this way, SCAN-PS could solve the cold
start problem when information of these new users is total absent in the target
network.Comment: 11 pages, 10 figures, 4 table
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