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Robust filtering for stochastic genetic regulatory networks with time-varying delay
This is the post print version of the article. The official published version can be obtained from the link - Copyright 2009 Elsevier LtdThis paper addresses the robust filtering problem for a class of linear genetic regulatory networks (GRNs) with stochastic disturbances, parameter uncertainties and time delays. The parameter uncertainties are assumed to reside in a polytopic region, the stochastic disturbance is state-dependent described by a scalar Brownian motion, and the time-varying delays enter into both the translation process and the feedback regulation process. We aim to estimate the true concentrations of mRNA and protein by designing a linear filter such that, for all admissible time delays, stochastic disturbances as well as polytopic uncertainties, the augmented state estimation dynamics is exponentially mean square stable with an expected decay rate. A delay-dependent linear matrix inequality (LMI) approach is first developed to derive sufficient conditions that guarantee the exponential stability of the augmented dynamics, and then the filter gains are parameterized in terms of the solution to a set of LMIs. Note that LMIs can be easily solved by using standard software packages. A simulation example is exploited in order to illustrate the effectiveness of the proposed design procedures.This work was supported in part by the Biotechnology and Biological Sciences Research Council (BBSRC) of the U.K. under Grants BB/C506264/1 and 100/EGM17735, an International Joint Project sponsored by the Royal Society of the U.K., the Research Grants Council of Hong Kong under Grant HKU 7031/06P, the National Natural Science Foundation of China under Grant 60804028, and the Alexander von Humboldt Foundation of Germany
H∞ controller design for networked predictive control systems based on the average dwell-time approach
This brief focuses on the problem of H∞ control for a class of networked control systems with time-varying delay in both forward and backward channels. Based on the average dwell-time method, a novel delay-compensation strategy is proposed by appropriately assigning the subsystem or designing the switching signals. Combined with this strategy, an improved predictive controller design approach in which the controller gain varies with the delay is presented to guarantee that the closed-loop system is exponentially stable with an H∞-norm bound for a class of switching signal in terms of nonlinear matrix inequalities. Furthermore, an iterative algorithm is presented to solve these nonlinear matrix inequalities to obtain a suboptimal minimum disturbance attenuation level. A numerical example illustrates the effectiveness of the proposed method
Perturbative analysis of generally nonlocal spatial optical solitons
In analogy to a perturbed harmonic oscillator, we calculate the fundamental
and some other higher order soliton solutions of the nonlocal nonlinear
Schroedinger equation (NNLSE) in the second approximation in the generally
nonlocal case. Comparing with numerical simulations we show that soliton
solutions in the 2nd approximation can describe the generally nonlocal soliton
states of the NNLSE more exactly than that in the zeroth approximation. We show
that for the nonlocal case of an exponential-decay type nonlocal response the
Gaussian-function-like soliton solutions can't describe the nonlocal soliton
states exactly even in the strongly nonlocal case. The properties of such
nonlocal solitons are investigated. In the strongly nonlocal limit, the
soliton's power and phase constant are both in inverse proportion to the 4th
power of its beam width for the nonlocal case of a Gaussian function type
nonlocal response, and are both in inverse proportion to the 3th power of its
beam width for the nonlocal case of an exponential-decay type nonlocal
response.Comment: 13 pages, 16 figures, accepted by Phys. Rev.
Demonstration of Shor's quantum factoring algorithm using photonic qubits
We report an experimental demonstration of a complied version of Shor's
algorithm using four photonic qubits. We choose the simplest instance of this
algorithm, that is, factorization of N=15 in the case that the period and
exploit a simplified linear optical network to coherently implement the quantum
circuits of the modular exponential execution and semi-classical quantum
Fourier transformation. During this computation, genuine multiparticle
entanglement is observed which well supports its quantum nature. This
experiment represents a step toward full realization of Shor's algorithm and
scalable linear optics quantum computation.Comment: small changes over v2; to appear in PR
Further results on peripheral-tube model for ridge correlation
Peripheral one-tube model has shown to be a nice tool for dynamically
understanding several aspects of ridge structures in long-range two-particle
correlations, observed experimentally and obtained also in our model
calculations using NexSPheRIO code. Here, we study an extension of the model,
to initial configurations with several peripheral tubes distributed randomly in
azimuth. We show that the two-particle correlation is almost independent of the
number of tubes, although the flow distribution becomes indeed strongly event
dependent. In our picture, the ridge structures are causally connected not only
in the longitudinal direction but also in azimuth.Comment: 6 pages, 3 figures, prepared for ISMD 2012 Proceeding
Hyperentangled Bell-state analysis
It is known that it is impossible to unambiguously distinguish the four Bell
states encoded in pairs of photon polarizations using only linear optics.
However, hyperentanglement, the simultaneous entanglement in more than one
degree of freedom, has been shown to assist the complete Bell analysis of the
four Bell states (given a fixed state of the other degrees of freedom). Yet
introducing other degrees of freedom also enlarges the total number of
Bell-like states. We investigate the limits for unambiguously distinguishing
these Bell-like states. In particular, when the additional degree of freedom is
qubit-like, we find that the optimal one-shot discrimination schemes are to
group the 16 states into 7 distinguishable classes, and that an unambiguous
discrimination is possible with two identical copies.Comment: typos corrected, to appear in PRA, 5 pages, 2 figures, 2 table
Optical parametric generator based on orientation-patterned gallium phosphide
We report the first pulsed optical parametric generator based on Orientation-patterned Gallium Phosphide. The output is tunable from 1721-1850 nm (signal) and 2504-2787 nm (idler), providing a total output power of 18 mW.Peer ReviewedPostprint (author's final draft
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