In this paper we present a filter-trust-region algorithm for solving LC1 unconstrained optimization problems which uses the second Dini upper directional derivative. We establish the global convergence of the algorith...In this paper we present a filter-trust-region algorithm for solving LC1 unconstrained optimization problems which uses the second Dini upper directional derivative. We establish the global convergence of the algorithm under reasonable assumptions.展开更多
The inexact Rayleigh quotient iteration (RQI) is used for computing the smallest eigenpair of a large Hermitian matrix. Under certain condition, the method was proved to converge quadratically in literature. However, ...The inexact Rayleigh quotient iteration (RQI) is used for computing the smallest eigenpair of a large Hermitian matrix. Under certain condition, the method was proved to converge quadratically in literature. However, it is shown in this paper that under the original given condition the inexact RQI may not quadratically converge to the desired eigenpair and even may misconverge to some other undesired eigenpair. A new condition, called the uniform positiveness condition, is given that can fix misconvergence problem and ensure the quadratic convergence of the inexact RQI. An alternative to the inexact RQI is the Jacobi-Davidson (JD) method without subspace acceleration. A new proof of its linear convergence is presented and a sharper bound is established in the paper. All the results are verified and analyzed by numerical experiments.展开更多
The delayed-state-derivative feedback （DSDF） is in- troduced into the existing consensus protocol to simultaneously improve the robustness to communication delay and accele- rate the convergence speed of achieving t...The delayed-state-derivative feedback （DSDF） is in- troduced into the existing consensus protocol to simultaneously improve the robustness to communication delay and accele- rate the convergence speed of achieving the consensus. The frequency-domain analysis, together with the algebra graph the- ory, is employed to derive the sufficient and necessary condition guaranteeing the average consensus. It is shown that introduc- ing the DSDF with the proper intensity in the existing consensus protocol can improve the robustness to communication delay. By analyzing the effect of DSDF on the closed-loop poles, this pa- per proves that for a supercritical-delay multi-agent system, this strategy can also accelerate the convergence speed of achieving the consensus with provided the proper intensity of the DSDE Simulations are provided to demonstrate the effectiveness of the theoretical results.展开更多
In this paper, the frequency-domain Frost algorithm is enhanced by using conjugate gradient techniques for speech enhancement. Unlike the non-adaptive approach of computing the optimum minimum variance distortionless ...In this paper, the frequency-domain Frost algorithm is enhanced by using conjugate gradient techniques for speech enhancement. Unlike the non-adaptive approach of computing the optimum minimum variance distortionless response （MVDR） solution with the correlation matrix inversion, the Frost algorithm implementing the stochastic constrained least mean square （LMS） algorithm can adaptively converge to the MVDR solution in mean-square sense, but with a very slow convergence rate. In this paper, we propose a frequency-domain constrained conjugate gradient （FDCCG） algorithm to speed up the convergence. The devised FDCCG algorithm avoids the matrix inversion and exhibits fast convergence. The speech enhancement experiments for the target speech signal corrupted by two and five interfering speech signals are demonstrated by using a four-channel acoustic-vector-sensor （AVS） micro-phone array and show the superior performance.展开更多
A new algorithm for inequality constrained optimization is presented, which solves a linear programming subproblem and a quadratic subproblem at each iteration. The algorithm can circumvent the difficulties associated...A new algorithm for inequality constrained optimization is presented, which solves a linear programming subproblem and a quadratic subproblem at each iteration. The algorithm can circumvent the difficulties associated with the possible inconsistency of QP subproblem of the original SQP method. Moreover, the algorithm can converge to a point which satisfies a certain first-order necessary condition even if the original problem is itself infeasible. Under certain condition, some global convergence results are proved and local superlinear convergence results are also obtained. Preliminary numerical results are reported.展开更多
A photonic crystal fiber(PCF)for sensing of sulfuric acid is designed and analyzed using Comsol Multiphysics.To analyze the sensor performance,0%,10%,20%,30%,40%H2SO4 solution is placed into the fiber separately and t...A photonic crystal fiber(PCF)for sensing of sulfuric acid is designed and analyzed using Comsol Multiphysics.To analyze the sensor performance,0%,10%,20%,30%,40%H2SO4 solution is placed into the fiber separately and then relative sensitivity,confinement loss,birefringence,effective area etc.are investigated for each solution over wavelength ranging from 0.8 to 1.8μm.The sensor structure affords moderately high relative sensitivity and around 63.4%sensitivity is achieved for the highest concentration of H2SO4 at the wavelength 1.5|im inxpolarization direction.This PCF model also shows zero confinement loss for all solutions of H2SO4 over wavelength ranging from 1 to 1.35μm and later on approximately 1.422×10^-17 dB/km confinement loss is found for the highest concentration of H2SO4 at 1.5|im wavelength.Besides,higher birefringence is attained when the concentration of sulfuric acid is lower and it is achieved 7.5×10^-4 at 1.5μm wavelength.Moreover,higher sensing area is achieved at high concentration of sulfuric acid.展开更多
基金Supported by CERG: CityU 101005 of the Government of Hong Kong SAR, Chinathe National Natural ScienceFoundation of China, the Specialized Research Fund of Doctoral Program of Higher Education of China (Grant No.20040319003)the Natural Science Fund of Jiangsu Province of China (Grant No. BK2006214)
文摘In this paper we present a filter-trust-region algorithm for solving LC1 unconstrained optimization problems which uses the second Dini upper directional derivative. We establish the global convergence of the algorithm under reasonable assumptions.
基金supported by the National Natural Science Foundation of China (Grant Nos. 10471074, 10771116)the Doctoral Program of the Ministry of Education of China (Grant No. 20060003003)
文摘The inexact Rayleigh quotient iteration (RQI) is used for computing the smallest eigenpair of a large Hermitian matrix. Under certain condition, the method was proved to converge quadratically in literature. However, it is shown in this paper that under the original given condition the inexact RQI may not quadratically converge to the desired eigenpair and even may misconverge to some other undesired eigenpair. A new condition, called the uniform positiveness condition, is given that can fix misconvergence problem and ensure the quadratic convergence of the inexact RQI. An alternative to the inexact RQI is the Jacobi-Davidson (JD) method without subspace acceleration. A new proof of its linear convergence is presented and a sharper bound is established in the paper. All the results are verified and analyzed by numerical experiments.
基金supported by the National Natural Science Foundation of China (60574088 60874053)
文摘The delayed-state-derivative feedback （DSDF） is in- troduced into the existing consensus protocol to simultaneously improve the robustness to communication delay and accele- rate the convergence speed of achieving the consensus. The frequency-domain analysis, together with the algebra graph the- ory, is employed to derive the sufficient and necessary condition guaranteeing the average consensus. It is shown that introduc- ing the DSDF with the proper intensity in the existing consensus protocol can improve the robustness to communication delay. By analyzing the effect of DSDF on the closed-loop poles, this pa- per proves that for a supercritical-delay multi-agent system, this strategy can also accelerate the convergence speed of achieving the consensus with provided the proper intensity of the DSDE Simulations are provided to demonstrate the effectiveness of the theoretical results.
基金supported by the Human Sixth Sense Programme at the Advanced Digital Sciences Center from Singapore’s Agency for Science,Technology and Research
文摘In this paper, the frequency-domain Frost algorithm is enhanced by using conjugate gradient techniques for speech enhancement. Unlike the non-adaptive approach of computing the optimum minimum variance distortionless response （MVDR） solution with the correlation matrix inversion, the Frost algorithm implementing the stochastic constrained least mean square （LMS） algorithm can adaptively converge to the MVDR solution in mean-square sense, but with a very slow convergence rate. In this paper, we propose a frequency-domain constrained conjugate gradient （FDCCG） algorithm to speed up the convergence. The devised FDCCG algorithm avoids the matrix inversion and exhibits fast convergence. The speech enhancement experiments for the target speech signal corrupted by two and five interfering speech signals are demonstrated by using a four-channel acoustic-vector-sensor （AVS） micro-phone array and show the superior performance.
基金This work is supported in part by the National Natural Science Foundation of China (Grant No. 10171055).
文摘A new algorithm for inequality constrained optimization is presented, which solves a linear programming subproblem and a quadratic subproblem at each iteration. The algorithm can circumvent the difficulties associated with the possible inconsistency of QP subproblem of the original SQP method. Moreover, the algorithm can converge to a point which satisfies a certain first-order necessary condition even if the original problem is itself infeasible. Under certain condition, some global convergence results are proved and local superlinear convergence results are also obtained. Preliminary numerical results are reported.
文摘A photonic crystal fiber(PCF)for sensing of sulfuric acid is designed and analyzed using Comsol Multiphysics.To analyze the sensor performance,0%,10%,20%,30%,40%H2SO4 solution is placed into the fiber separately and then relative sensitivity,confinement loss,birefringence,effective area etc.are investigated for each solution over wavelength ranging from 0.8 to 1.8μm.The sensor structure affords moderately high relative sensitivity and around 63.4%sensitivity is achieved for the highest concentration of H2SO4 at the wavelength 1.5|im inxpolarization direction.This PCF model also shows zero confinement loss for all solutions of H2SO4 over wavelength ranging from 1 to 1.35μm and later on approximately 1.422×10^-17 dB/km confinement loss is found for the highest concentration of H2SO4 at 1.5|im wavelength.Besides,higher birefringence is attained when the concentration of sulfuric acid is lower and it is achieved 7.5×10^-4 at 1.5μm wavelength.Moreover,higher sensing area is achieved at high concentration of sulfuric acid.
