Advanced Materials Research Vols. 204-210

Abstract: Because blind adaptive beamforming algorithms do not depend on any reference signal, they have found numerous important applications in signal processing. However, the conventional constrained constant modulus algorithm (CMA) may suffer significant performance degradation in the presence of the slight mismatches between the actual and assumed signal steering vectors. In this paper, to combat the mismatches, a novel robust constrained CMA is proposed for implementing double constraints with recursive method updating, which is based on explicit modeling of uncertainties in the desired signal array response. The proposed robust constrained CMA provides an improved robustness against the signal steering vector mismatches, enhances the array system performance under random perturbations in sensor parameters and makes the mean output array SINR consistently close to the optimal one. The performance of the proposed algorithm is compared with that of linear constrained CMA algorithm by computer simulations, the results of which demonstrate a marked improvement in the robustness against signal steering vector mismatches.

Abstract: This paper presents an automatic road sign detection and recognition system based on binary tree SVM. Color based segmentation techniques are employed for traffic sign detection. The coordinates position of traffic sign in images used for shape classification are obtained by orthogonal projection. An algorithm based on Hough transform was proposed to achieve better shape classification performance.Recognition of traffic signs are implemented using binary tree multi- classifer SVM with geometry semantic feature as the feature vector

Abstract: IP multicast protocols tend to construct a single minimum spanning tree for a multicast source (i.e., group), in which only a few internal nodes supply multicast traffic. In multicast networks especially with multiple multicast sources where bottleneck effects may occur frequently, frequently used multicast service leads to inefficient network utilization problems. This paper presents a new network utilization algorithm for multicasting called load distribution algorithm (LDA). The LDA algorithm uses selecting candidate path based on ant colony algorithm and multicast scheduling to distribute the contention multicast packets onto their corresponding candidate paths. The numerical results show that a multicast protocol with LDA has higher efficiency of resource utilization and meanwhile maintains less end to end delay compared with the original one without LDA.

Abstract: This paper tested the measures of compactness of fuzzy partitions. Over the same labeled data, Fuzzy k-Means clustering algorithm generates the first partition, then the proposed revision function in (7) revises it several times to generate various fuzzy partitions with different pattern recognition rates computed by (6), finally the measures of compactness measure the compactness of each fuzzy partition. Experimental results on real data show that the measures of compactness in literatures fail to measure the compactness of a fuzzy clustering in some cases, for they argue that the fuzzy clustering with higher pattern recognition rate is less compact and worse than that with lower pattern recognition rate.

Abstract: We present an improved method to detect moving object and obtain the relative accurate location in this paper. The Canny detector is applied to detect the edge of image, which is the edge difference of continuous frames. Then we utilize the pair of moving object information to reach a good detection of the moving object and location. The extensive experiments show that our method is efficient to the moving object detection.

Abstract: A new approach to gear localized fault diagnosis under run-up based on angle domain average and Teager Kaiser energy operator demodulation technique is presented. The non-stationary vibration signals are transformed from the time domain transient signal to angle domain stationary one using order tracking technique. Teager Kaiser energy operator is a nonlinear operator that can track the signal energy and identify the instantaneous frequency and instantaneous amplitude of mono-component signal. The instantaneous frequency and instantaneous amplitude both exhibit a characteristic signature in the presence of a cracked tooth. The experimental result shows that angle domain average and Teager Kaiser energy operator demodulation technique can effectively diagnose gear localized crack fault.

Abstract: By studying the conventional algorithm of contour extraction, a new method of contour extraction in blood vessel of brain is proposed based on the MOC maximum optimization cost. First of all, the theory computes the gray differential of the image by conventional differential method to build the cost space. Then, by using dynamic programming theory, the maximum optimization cost curve in the space is extracted to serve as the specific cerebrovascular profile. The experiments show that this method ensures high efficiency in extracting cerebrovascular contour and a high accuracy in positioning cerebrovascular contour, and it diminishes the target image ambiguity caused by noise to improve the anti-interference ability of Contour extraction.

Abstract: Image fusion is to combine several different source images to form a new image by using a certain method. Recent studies show that among a variety of image fusion algorithms, the wavelet-based method is more effective. In the wavelet-based method, the key technique is the fusion scheme, which can decide the final fused result. This paper presents a novel fusion scheme that integrates the wavelet decomposed coefficients in a quite separate way when fusing images. The method is formed by considering the different physical meanings of the coefficients in both the low frequency and high frequency bands. The fused results were compared with several existing fusion methods and evaluated by three measures of performance. The experimental results can demonstrate that the proposed method can achieve better performance than conventional image fusion methods.

Abstract: The basic test of the phased-array Doppler sonar velocity system made by us indicates that the positioning errors are large. From the positioning result, it can be known that compass error is the dominant factor. Therefore, to improve the measurement precision of compass and revise its course deviation is one of the keys to improve the accuracy of Doppler positioning. From the speed processing result, it shows that the positioning accuracy can be further improved through averaging the speed (smoothing).

Abstract: The paper gives out the calibration method of the sensitivity and phase to a vector hydrophone; it analysed the data from the lake trial and the sea trial. The results indicate that, in the isotropic noise field, the sound pressure and the velocity are not related, but the signals are completely relevant. When there is no coherent interference, both the average sound intensity device and the diagram of the target orientation estimation can efficiently estimate the target orientation; when there is the interference of a strong line spectrum, the average sound intensity device cannot work properly, but the diagram can still effectively estimate the target position; when the target radiates spectrum, the line spectrum of the target orientation estimation can still have very good performance.