Sun Xiaoying

A discriminative method for speaker identification with limited data

Speaker recognition system needs sufficient data to discriminate speaker well. In case of limited data, especially when the amount of available training and testing data were few seconds, the system performance decreased significantly. It proposed a discriminative weighted fuzzy kernel vector quantization method for speaker identification with limited data. By non-linear mapping, it quantized the input data in the high-dimensional feature space, and used the cluster centers to form the speakers model. In the matching phase, it took into account the relationship between the reference models in feature space, and assigned the larger weights for code vectors with high discriminative power. Experimental results show that when the training data and testing data is limited, this method can provide good performance.

Double exponential model of ultrasonic signals

The notion of representing discrete-time ultrasonic signals using double exponential model and the method of computing modelpsilas parameters using Prony method are introduced. The rise time tr and full width half maximum tfwhm of double exponential model is discussed and contrasted with the damped exponential model. It is shown that flexibility of double exponent model is superior to damped exponential model. Fitting the measured data and simulation of TOA (Time-Of-Arrived) proved that the double exponent model has better performance than the damped exponential model.

A New Joint Estimation Method of DOA and Polarization Based on MP

A method is presented for the estimation of DOA, and polarization parameters of far-field sources based on four order cumulant. The method adopts ULA array, and every sensor consists of orthogonal dipole-pairs with the same coordinate axis direction, which measure the x-axis and y-axis electric-field components of the far-field signals. The method constructs three four-order cumulant matrixes by receiving polarized array data, and estimates the parameters of far-field according to the MP algorithm. The method does not require any spectral peak search and easy parameter pairing only, can be applied to additive Gaussian white noise environment. The performance of the proposed method is verified by computer simulations.

Real-coded generic algorithm for optimized digital watermarking embedding in time-domain

To reduce the effects of the watermarking embedding on graphic visibility, the optimal watermarking embedding problem using generic algorithm in Time-Domain is researched in this paper and a real-coded generic algorithm for optimized digital watermarking embedding in Time-Domain technique is proposed. Through analyzing the corresponding relationship between genotype and phenotype of decision variables, a real-coded algorithm applying position of embedded points as the genotype of the decision variables is proposed. Moreover, this algorithm improves the invisibility and the operating precision of images and reduces the operating complexity shown in simulating experiments.

Study of the electromagnetic shielding effectiveness of perforated rectangular enclosure with external waveguide based on equivalent circuit method

ABSTRACT An analytical model based on the equivalent circuit method is presented to predict the electromagnetic shielding effectiveness (SE) of perforated metallic rectangular enclosure with external waveguide. In this model, the electrically small aperture is represented by a four-terminal network, and the external waveguide and enclosure are modeled as transmission line. By this way, the SE of any position of the enclosure under planewave illumination can be calculated fast and accurately over a wide frequency range (0 ~ 3 GHz). Simulation results of the proposed model are in accord with that of the transmission line matrix method, which verifies the accuracy and reliability of the model. The shielding characteristics of the perforated enclosure with external waveguide are also analyzed. The effects of parameters of aperture position, observation point position, and external waveguide length are discussed in detail. Simulation results show that the external waveguide can effectively improve the SE of the enclosure with aperture. What’s more, the shielding performance of perforated enclosure with external waveguide outperforms the perforated double-layer enclosure in some cases. For a certain length of the waveguide, the longer the edge of aperture which is perpendicular to the direction of the electric field is, the worse the shielding effect of the external waveguide on the enclosure becomes. The SE of the enclosure increases with increase of the length of the external waveguide.