Huijing Dou

Voice activity detection based on the bispectrum

In order to improve the performance of voice activity detection under multiple noise environments, a new voice activity detection algorithm based on the bis-pectrum was presented. This method detect the speech signal by using the special slice of the bispectrum. The performance of the algorithm was compared with the voice activity detection algorithm in standard G.729 annex B of ITU in experimental simulation. Experimental results show that the algorithm has high classification accuracy and stability.

Pitch detection method for noisy speech signals based on pre-filter and weighted wavelet coefficients

Most of the current pitch detection algorithms can not work well under the high noise environment. For this reason, a pitch detection algorithm for noisy speech signal based on pre-filtering and weighted wavelet coefficients is proposed. Firstly, the noisy speech signals are pre-filtered. Secondly, the speech pre-filtered is decomposed by the quadratic spline wavelet. Thirdly, the wavelet coefficients of three consecutive scales are weighted to emphasize the sharp change points. Fourthly, three candidate pitch periods are extracted from the weighted signals. Finally, the pitch period is calculated by autocorrelation function. Experiments show that this algorithm can increase the performance of pitch detection in noisy environment and decreases computational complexity compared with DWT-NCCF method.

A voice activity detection using cyclic statistics based on sinusoidal speech model

In this paper, by using the cyclostationary properties of speech signal, a voice activity detection (VAD) algorithm based on cyclic cumulant is proposed. The proposed scheme employs the third-order cyclic cumulant of the LPC residual of a speech signal. Analytical expressions for the third-order cyclic cumulant of the LPC residual of short-term speech are derived assuming a sinusoidal model. Matrix pencil method (MP) are adopted to estimate the frequencies of harmonic signal contained in LPC residual of speech signal, which are used as the cyclic frequencies of cyclic cumulant. Then the third-order cyclic cumulant is defined and used to construct the VAD detection variation. The test results show that the proposed algorithm gives better results than G.729B VAD.

A new TDOA estimation method in Three-satellite interference localisation

Time difference of arrival (TDOA) parameter estimation is the key to Three-satellite interference localisation. Therefore, in order to improve the accuracy of Three-satellite interference location, we must estimate the TDOA parameter accurately and effectively. Based on the study of wavelet transform correlation TDOA estimation algorithm, combining with correlation and Hilbert subtraction method, we put forward a high precision TDOA estimation method for Three-satellite interference location. The proposed algorithm utilises the characteristics of the zero-crossing point of Hilbert transform method corresponding to the correlation peak point of correlation method, using correlation function of wavelet transform correlation method minus the absolute value of its Hilbert transform, to sharpen peak point and improve the TDOA estimation precision, so that the positioning is more accurate and effective.

Research on joint DOA and polarization estimation for alternate polarization array

For polarization sensitive array (PSA) is limited by many restrictions in engineering applications, we studies a new alternate polarization array (APA). Analysis its performance of joint spectrum estimation of polarizational and spatial domain, and compared with the PSA. Study shows that compared with the PSA, the joint spectrum estimation of polarizational and spatial domain performance of APA approaches that of PSA, but the equipments and the number of channel is cut by half. APA overcomes the problems caused by the complexity of the PSA system, so it has a wide application prospect in the field of array radar.

A Fast Audio Information Retrieval Method Based on Part-Whole Recursion

This paper proposes a fast audio information retrieval algorithm based on part-whole recursion, which could reduce retrieval time greatly when query audio is very long. In order to speed up search speed, this paper firstly extracts audio fingerprint features, which changed float type features into binary bits for calculation quickly; Secondly, utilizes time sequence information and negativity judgment sufficiently in matching procedure, which could reduce search range largely. Experimental results show that the proposed audio fingerprint algorithm is more robust than the famous Philips’ algorithm, which the bit error rate is nearly decreased 35%; the part-whole recursion scheme is much faster than whole matching and segment-based retrieval scheme, and also has a high precision rate and recall rate when the query audio is very long.

An effective information filtering method based on the LTE network

With the rapid development of the information technology, more and more high-speed networks came out. The 4G LTE network as a recently emerging network has gradually entered the mainstream of the communication network. This paper proposed an effective content-based information filtering based on the 4G LTE high-speed network by combing the content-based filter and traditional simple filter. Firstly, raw information is pre-processed by five-tuple filter. Secondly, we determine the topics and character of the source data by key nearest neighbor text classification after minimum-risk Bayesian classification. Finally, the improved AdaBoost algorithm achieves the four-level content-based information filtering. The experiments reveal that the effective information filtering method can be applied to the network security, big data analysis and other fields. It has high research value and market value.

Filtering performance of alternate polarization array based on the technology of oblique projection

The traditional PSA (Polarization Sensitive Array) is made up of orthogonal dipole mostly, doubling equipment in exchange for superior performance. But the increase of equipment limits its application in radar system. APA (Alternating Polarization Array) can simplify equipment at the same time ensure the filtering performance. In this paper, taking advantage of the excellent properties of oblique projection technology, it applied oblique projection technology to APA, realizing the simplification of the system, while retaining the phase and amplitude information of the target signal. Simulation results indicate that its filtering performance approaches that of PSA.

The Research on Performances of Dual Receivers Positioning System

Passive geolocation of communication emitters provides great benefits to military and civilian surveillance and security operations. Measurement combination for stationary emitters based on Time Difference of Arrival (TDOA) and Frequency Difference of Arrival (FDOA) may be obtained by sensors mounted on mobile platforms, for example, on a pair of Unmanned Aerial Vehicles (UAVs). This paper relies on joint TDOA/FDOA estimation algorithm. Then we put forward a kind of method by adjusting the receiver direction to improve the precision of localization. The results of the simulation show that the method can improve precision of the positioning 2–10 times.

Automatic Classification between Wind and Bowstring Instrumental Music Using Support Vector Machine

The automatic musical instrument classification has many applications such as music information retrieval, music reconstruction and audio classification. In this paper, wind instrumental music and bowstring instrumental music are studied based on the database consisting of 2896 clips from 8 different classes of musical instruments (horn, clarinet, oboe, trumpet, cello, viola, violin, and doublebass). With audio features including spectral centroid, spectral spread, low energy frame ratio, Mel-Frequency Cepstral Coefficients, formant frequency interval, and fundamental frequency, classification using Support Vector Machine whose parameters are optimized by Particle Swarm Optimization searching algorithm, gives an accuracy of 92.22%, the accuracy is close to or better than the ones reported on the similar data sets and using other classifiers.