The phase difference method (PDM) is presented for the direction of arrival (DOA) estimation of the narrowband source. It estimates the DOA by measuring the reciprocal of the phase range of the sensor output spectra a...The phase difference method (PDM) is presented for the direction of arrival (DOA) estimation of the narrowband source. It estimates the DOA by measuring the reciprocal of the phase range of the sensor output spectra at the interest frequency bin. The peak width and variance of the PDM are presented. The PDM can distinguish closely spaced sources with different and unknown center frequencies as long as they are separated with at least one frequency bin. The simulation results show that the PDM has a better resolution than that of the conventional beamforming.展开更多
An approach based on multi-scale ehirplet sparse signal decomposition is proposed to separate the malti-component polynomial phase signals, and estimate their instantaneous frequencies. In this paper, we have generate...An approach based on multi-scale ehirplet sparse signal decomposition is proposed to separate the malti-component polynomial phase signals, and estimate their instantaneous frequencies. In this paper, we have generated a family of multi-scale chirplet functions which provide good local correlations of chirps over shorter time interval. At every decomposition stage, we build the so-called family of chirplets and our idea is to use a structured algorithm which exploits information in the family to chain chirplets together adaptively as to form the polyncmial phase signal component whose correlation with the current residue signal is largest. Simultaueously, the polynomial instantaneous frequency is estimated by connecting the linear frequency of the chirplet functions adopted in the current separation. Simulation experiment demonstrated that this method can separate the camponents of the multi-component polynamial phase signals effectively even in the low signal-to-noise ratio condition, and estimate its instantaneous frequency accurately.展开更多
Studies of repetition priming have found two face-sensitive event-related potential(ERP) components:the N250 r showing positive deflection at frontal region and negative deflection at temporal region, and the N400 sho...Studies of repetition priming have found two face-sensitive event-related potential(ERP) components:the N250 r showing positive deflection at frontal region and negative deflection at temporal region, and the N400 showing positive deflection at frontal and centro-parietal regions, both of which depend in part upon the presence or absence of a pre-existing face representation. However, the N250 r is rarely reported for a repetition interval between immediate repetition and 3 min; in addition, whether different types of representations function in the same way is also of interest. The goal of the present experiment is to compare the ERP patterns for faces versus letter strings as a function of the pre-existing memory representation with a repetition interval of 1.5 min on average. We found reliable frontally positive N250 r and N400 for famous faces and words; marginally significant effects for pseudo-words;and only the centro-parietal N400 for unfamiliar faces.Collectively, the N250 r persists in the present intermediate intervals, and both the frontal N250 r and the frontal N400 are domain-general, sensitive to the pre-existing memory representation.展开更多
基金the National Science Foundation under Grant No. 60672136the the Doctorate Foundation of Northwestern Polytechnical University under Grant No.CX200803
文摘The phase difference method (PDM) is presented for the direction of arrival (DOA) estimation of the narrowband source. It estimates the DOA by measuring the reciprocal of the phase range of the sensor output spectra at the interest frequency bin. The peak width and variance of the PDM are presented. The PDM can distinguish closely spaced sources with different and unknown center frequencies as long as they are separated with at least one frequency bin. The simulation results show that the PDM has a better resolution than that of the conventional beamforming.
基金supported by the National Science Foundation of China(No.50875078)
文摘An approach based on multi-scale ehirplet sparse signal decomposition is proposed to separate the malti-component polynomial phase signals, and estimate their instantaneous frequencies. In this paper, we have generated a family of multi-scale chirplet functions which provide good local correlations of chirps over shorter time interval. At every decomposition stage, we build the so-called family of chirplets and our idea is to use a structured algorithm which exploits information in the family to chain chirplets together adaptively as to form the polyncmial phase signal component whose correlation with the current residue signal is largest. Simultaueously, the polynomial instantaneous frequency is estimated by connecting the linear frequency of the chirplet functions adopted in the current separation. Simulation experiment demonstrated that this method can separate the camponents of the multi-component polynamial phase signals effectively even in the low signal-to-noise ratio condition, and estimate its instantaneous frequency accurately.
基金the National Natural Science Foundation of China (31300831)Zhejiang Provincial Social Science Foundation of China (14NDJC012Z)
文摘Studies of repetition priming have found two face-sensitive event-related potential(ERP) components:the N250 r showing positive deflection at frontal region and negative deflection at temporal region, and the N400 showing positive deflection at frontal and centro-parietal regions, both of which depend in part upon the presence or absence of a pre-existing face representation. However, the N250 r is rarely reported for a repetition interval between immediate repetition and 3 min; in addition, whether different types of representations function in the same way is also of interest. The goal of the present experiment is to compare the ERP patterns for faces versus letter strings as a function of the pre-existing memory representation with a repetition interval of 1.5 min on average. We found reliable frontally positive N250 r and N400 for famous faces and words; marginally significant effects for pseudo-words;and only the centro-parietal N400 for unfamiliar faces.Collectively, the N250 r persists in the present intermediate intervals, and both the frontal N250 r and the frontal N400 are domain-general, sensitive to the pre-existing memory representation.
