127,411 research outputs found
Dynamic Topology Adaptation Based on Adaptive Link Selection Algorithms for Distributed Estimation
This paper presents adaptive link selection algorithms for distributed
estimation and considers their application to wireless sensor networks and
smart grids. In particular, exhaustive search--based
least--mean--squares(LMS)/recursive least squares(RLS) link selection
algorithms and sparsity--inspired LMS/RLS link selection algorithms that can
exploit the topology of networks with poor--quality links are considered. The
proposed link selection algorithms are then analyzed in terms of their
stability, steady--state and tracking performance, and computational
complexity. In comparison with existing centralized or distributed estimation
strategies, key features of the proposed algorithms are: 1) more accurate
estimates and faster convergence speed can be obtained; and 2) the network is
equipped with the ability of link selection that can circumvent link failures
and improve the estimation performance. The performance of the proposed
algorithms for distributed estimation is illustrated via simulations in
applications of wireless sensor networks and smart grids.Comment: 14 figure
Finite-Difference Lattice Boltzmann Methods for binary fluids
We investigate two-fluid BGK kinetic methods for binary fluids. The developed
theory works for asymmetric as well as symmetric systems. For symmetric systems
it recovers Sirovich's theory and is summarized in models A and B. For
asymmetric systems it contributes models C, D and E which are especially useful
when the total masses and/or local temperatures of the two components are
greatly different. The kinetic models are discretized based on an octagonal
discrete velocity model. The discrete-velocity kinetic models and the
continuous ones are required to describe the same hydrodynamic equations. The
combination of a discrete-velocity kinetic model and an appropriate
finite-difference scheme composes a finite-difference lattice Boltzmann method.
The validity of the formulated methods is verified by investigating (i) uniform
relaxation processes, (ii) isothermal Couette flow, and (iii) diffusion
behavior.Comment: RevTex, 3 figures. Phys. Rev. E (2005, in press
Dimerization-assisted energy transport in light-harvesting complexes
We study the role of the dimer structure of light-harvesting complex II (LH2)
in excitation transfer from the LH2 (without a reaction center (RC)) to the LH1
(surrounding the RC), or from the LH2 to another LH2. The excited and
un-excited states of a bacteriochlorophyll (BChl) are modeled by a quasi-spin.
In the framework of quantum open system theory, we represent the excitation
transfer as the total leakage of the LH2 system and then calculate the transfer
efficiency and average transfer time. For different initial states with various
quantum superposition properties, we study how the dimerization of the B850
BChl ring can enhance the transfer efficiency and shorten the average transfer
time.Comment: 11 pages, 6 figure
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