This paper presents a robust time delay estimation algorithm for the α-Stable noise based on correntropy. Many time delay estimation algorithms derived for impulsive stable noise are based on the theory of Fractional...This paper presents a robust time delay estimation algorithm for the α-Stable noise based on correntropy. Many time delay estimation algorithms derived for impulsive stable noise are based on the theory of Fractional Lower Order Statistics (FLOS). Unlike previously introduced FLOS-type algorithms, the new algorithm is proposed to estimate the time delay by maximizing the generalized correlation function of two observed signals needing neither prior information nor estimation of the numerical value of the stable noise's characteristic exponent. An interval for kernel selection is found for a wide range of characteristic exponent values of α-Stable distribution. Simulations show the proposed algorithm offers superior performance over the existing covariation time delay estimation, least mean p-norm time delay estimation and achieves slightly improved performance than fractional lower order covariance time delay estimation at lower signal to noise ratio when the noise is highly impulsive.展开更多
We present photoluminescence studies on highly dense two-dimensional electron gases in selectively Siδ-doped GaAs/ln_(0.18)Ga_(0.82) As/Al_(0.25)Ga_(0.75),As quantum wells(Ns=4.24 × 10^(12) cm^(-2)).Five well-re...We present photoluminescence studies on highly dense two-dimensional electron gases in selectively Siδ-doped GaAs/ln_(0.18)Ga_(0.82) As/Al_(0.25)Ga_(0.75),As quantum wells(Ns=4.24 × 10^(12) cm^(-2)).Five well-resolved photoluminescence lines centered at 1.4194,1.4506,1.4609,1.4695 and 1.4808eV were observed,which are attributed to the subband exciton emission.The subband separations clearly exhibit the feature of a typical quantum well with triangle and square potential.These very intensive and sharp luminescence peaks with linewidths of 2.2 to 3.5meV indicate the high quality of the structures.Their dependence on the excitation intensity and temperatures are also discussed.展开更多
基金Supported by the Chinese National Science Foundation(No.60872122)
文摘This paper presents a robust time delay estimation algorithm for the α-Stable noise based on correntropy. Many time delay estimation algorithms derived for impulsive stable noise are based on the theory of Fractional Lower Order Statistics (FLOS). Unlike previously introduced FLOS-type algorithms, the new algorithm is proposed to estimate the time delay by maximizing the generalized correlation function of two observed signals needing neither prior information nor estimation of the numerical value of the stable noise's characteristic exponent. An interval for kernel selection is found for a wide range of characteristic exponent values of α-Stable distribution. Simulations show the proposed algorithm offers superior performance over the existing covariation time delay estimation, least mean p-norm time delay estimation and achieves slightly improved performance than fractional lower order covariance time delay estimation at lower signal to noise ratio when the noise is highly impulsive.
文摘We present photoluminescence studies on highly dense two-dimensional electron gases in selectively Siδ-doped GaAs/ln_(0.18)Ga_(0.82) As/Al_(0.25)Ga_(0.75),As quantum wells(Ns=4.24 × 10^(12) cm^(-2)).Five well-resolved photoluminescence lines centered at 1.4194,1.4506,1.4609,1.4695 and 1.4808eV were observed,which are attributed to the subband exciton emission.The subband separations clearly exhibit the feature of a typical quantum well with triangle and square potential.These very intensive and sharp luminescence peaks with linewidths of 2.2 to 3.5meV indicate the high quality of the structures.Their dependence on the excitation intensity and temperatures are also discussed.
