12,189 research outputs found
Compressed Distributed Gradient Descent: Communication-Efficient Consensus over Networks
Network consensus optimization has received increasing attention in recent
years and has found important applications in many scientific and engineering
fields. To solve network consensus optimization problems, one of the most
well-known approaches is the distributed gradient descent method (DGD).
However, in networks with slow communication rates, DGD's performance is
unsatisfactory for solving high-dimensional network consensus problems due to
the communication bottleneck. This motivates us to design a
communication-efficient DGD-type algorithm based on compressed information
exchanges. Our contributions in this paper are three-fold: i) We develop a
communication-efficient algorithm called amplified-differential compression DGD
(ADC-DGD) and show that it converges under {\em any} unbiased compression
operator; ii) We rigorously prove the convergence performances of ADC-DGD and
show that they match with those of DGD without compression; iii) We reveal an
interesting phase transition phenomenon in the convergence speed of ADC-DGD.
Collectively, our findings advance the state-of-the-art of network consensus
optimization theory.Comment: 11 pages, 11 figures, IEEE INFOCOM 201
A hybrid model approach for strange and multi-strange hadrons in 2.76 A TeV Pb+Pb collisions
Using the VISHNU hybrid model, we calculate the multiplicity, spectra, and
elliptic flow of , and in 2.76 A TeV Pb+Pb collisions.
Comparisons between our calculations and the ALICE measurements show that the
model generally describes the soft hadron data of these strange and
multi-strange hadrons at several centrality bins. Mass ordering of elliptic
flow among , K, p, , and has also been studied and
discussed. With a nice description of the particle yields, we explore chemical
and thermal freeze-out of various hadrons species at the LHC within the
framework of the VISHNU hybrid model.Comment: version 2: with several references added, published in PR
Suppression of nano-channel ion conductance by electro-osmotic flow in nano-channels with weakly overlapping electrical double layers
This theoretical study investigates the nonlinear ionic current-voltage
characteristics of nano-channels that have weakly overlapping electrical double
layers. Numerical simulations as well as a 1-D mathematical model are developed
to reveal that the electro-osmotic flow (EOF) interplays with the
concentration-polarization process and depletes the ion concentration inside
the channels, thus significantly suppressing the channel conductance. The
conductance may be restored at high electrical biases in the presence of
recirculating vortices within the channels. As a result of the EOF-driven ion
depletion, a limiting-conductance behavior is identified, which is
intrinsically different from the classical limiting-current behavior
- …