Table of Content

01 March 2013, Volume 33 Issue 03

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Network and communications

Channel allocation model and credibility evaluation for LBS indoor nodes

LIU Zhaobin LIU Wenzhi FANG Ligang TANG Yazhe

2013, 33(03):  603-606.  DOI: 10.3724/SP.J.1087.2013.00603

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In response to the issue that GPS is unable to carry out Location-Based Service (LBS) in indoor environment, a LBS indoor channel allocation model, credibility evaluation and control method was presented in this paper, which integrated GPS, Wi-Fi, ZigBee and Bluetooth technologies. It solved the problem arising from combination channel allocation, including the evaluation of the traffic load, the available Radio Frequency (RF), and non-overlapping RF channels number of each node. Each Access Point(AP)'s signal strength built the prediction model with reference point. The optimization algorithm was designed to determine and select the credibility of combination channel based on the energy evaluation. It adaptively selected neighbors with highest comprehensive effects to participate in iterative optimization. The simulation result indicates this method can effectively inhibit the proliferation of communication interference error in the network, reduce the positioning complexity, and improve the positioning accuracy in addition to improving scalability and robustness of the entire network.

Joint estimation-decoding approach based on factor graph expectation maximization algorithm over correlated block fading channels

YAN Bin JIA Xia WANG Xiaoming GUO Yinjing HAO Jianjun

2013, 33(03):  607-610.  DOI: 10.3724/SP.J.1087.2013.00607

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To deal with the channel uncertainty of the correlated block fading channels, a joint estimation-decoding approach based on Factor Graph Expectation Maximization (FGEM) algorithms was proposed. In the receiver, a message passing method on factor graph was adopted to jointly estimate the channel and decode the message. EM algorithm was used to remove the effect of loops on the convergence of message passing. It also solved the calculation problem of Gaussian mixture message. The calculation of message passing was simplified by the Kalman forward-backward algorithm, which resulted in reduced complexity in joint estimation-decoding. The simulation results show that the proposed algorithm can improve the accuracy of the channel estimation and improve the decoding performance.

Method of improving passive positioning accuracy based on Beidou satellite

ZHANG Yu LIU Ying HE Qiurui

2013, 33(03):  611-613.  DOI: 10.3724/SP.J.1087.2013.00611

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Beidou satellite has been used as external illuminator due to its features such as continuous coverage to our country, less motion relative to the earth, unapparent Doppler frequency, simple disturbance of adjacent channel and high security. Taking account of the location error caused by atmospheric refraction, a location error correction method was given, to further improve the position accuracy. The simulation results show that radar position errors could reduce correspondingly with the increase of elevation or the decrease of target altitude. Passive radar position accuracy is improved greatly by correcting atmospheric refraction.

Novel anti-collision algorithm of RFID sensor system for Internet of things

WU Liming CHEN Taiwei XIANG Ying

2013, 33(03):  614-617.  DOI: 10.3724/SP.J.1087.2013.00614

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The system of Internet of Things (IoT) based on ultra high frequency Radio-Frequency-IDentification (RFID) usually needs multiple readers to work simultaneously in the same area. Multi-reader collision takes place under this multi-reader environment, which will affect the system performance. Based on backscatter modulation, Signal to Interference Ratio (SIR) was selected as the measurement of communication quality, and the reader anti-collision algorithm based on power control and backoff algorithm was proposed in this paper. Readers dynamically adjust their transmission power according to SIR, to ensure the detection range and to reduce redundancy of their coverage area for anti-collision. Considering that some target SIR may not be achieved yet when the transmit power is adjusted to maximum, a new backoff algorithm was proposed. In backoff process, the reader reduced its power actively, and kept it for some time which is mapped into the proportion of target SIR iteration. The simulation results show the reader can adjust the power with fast convergence, and improve the real-time and reliability of RFID system. The backoff algorithm ensures the fairness of channel occupation. More importantly, it can reduce the power consumption, which is important for mobile readers. The reader anti-collision algorithm can effectively reduce redundancy of their coverage area and thereby minimize the reader collision, but also can ensure the detection range and thereby enhance read rate.

Receiver-initiated asynchronous MAC protocol for wireless sensor networks

WANG Lin WANG Xiaozhe

2013, 33(03):  618-620.  DOI: 10.3724/SP.J.1087.2013.00618

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Based on a Receiver-Initiated Medium Access Control (RI-MAC) protocol, a new receiver-initiated asynchronous Medium Access Control (MAC) protocol called Receiver-Predictive MAC (RP-MAC) protocol was proposed for the purpose of reducing the energy consumption caused by idle listening in wireless sensor networks. The wakeup time of the receiving node could be predicted by RP-MAC. In the proposed MAC protocol, a random number was used as a wakeup interval, the next wakeup time was forecasted by the previous two wakeup intervals, and the retransmission mechanism of RI-MAC was improved as well, thereby the idle listening and network conflicts were reduced. The simulation on NS2 shows that the duty cycle of the node work is significantly reduced by the improved MAC protocol in high load network, and the delivery rate of packet is successfully improved, and the network energy consumption is reduced at the same time.

Adaptive nonlinear RED algorithm based on routing queue resources

YANG Xiaoya HE Wansheng

2013, 33(03):  621-624.  DOI: 10.3724/SP.J.1087.2013.00621

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Concerning the shortcoming and complexity of Random Early Detection (RED) algorithm in network congestion control, the authors proposed a new adaptive algorithm (ND-RED) based on the routing queue resources, which used nonlinear packet loss strategies and can dynamically adjust computation parameter, so that queue length could keep stable in the neighborhood of reference value, thereby network congestion was controlled and network resource was used effectively. The stability of this model was studied. The experimental results show that the proposed algorithm can improve the stability and outperform the RED algorithm.

Variable step-size constant modulus algorithm based on exponential multi-delay error signal autocorrelation

ZHANG Yanping JI Lei2

2013, 33(03):  625-627.  DOI: 10.3724/SP.J.1087.2013.00625

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In order to further improve the convergence speed of the exponential variable step-size constant module algorithm, a variable step-size constant module algorithm based on the exponential multi-delay error signal autocorrelation was proposed on the basis of the analysis of the error signal autocorrelation, and the multi-delay error signal autocorrelation functions were adopted to control the steps. Compared with the non-delay and unit delay, the multi-delay error signal autocorrelation of the algorithm can provide simpler and more accurate information for training trajectory, so the algorithm converges faster, and the convergence process is smoother and more stable. The underwater acoustic channel simulation experiments further verify the advantage of the algorithm in the convergence speed.

Zero forcing beamforming adaptive precoding scheme based on two-level codebook

ZHANG Zhiyu LI Min

2013, 33(03):  628-630.  DOI: 10.3724/SP.J.1087.2013.00628

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In this paper, a Zero Forcing BeamForming (ZFBF) precoding scheme based on two-level codebook was proposed. The defect, that the performance of ZFBF precoding scheme was worse with fewer feedback bits in the multi-user Multiple Input Multiple Output (MIMO) system upon limited feedback, was well overcome by this scheme. In the proposed scheme, unitary matrix was combined with random vector codebook. The best beamforming vector in the one-level codebook was searched firstly and then the Signal to Interference and Noise Ratio (SINR) corresponding with the best beamforming vector in the disturbance range of orthogonal vector was calculated. Finally, the user's feedback information was decided by comparing the SINR calculated with the SINR threshold value set by system. At last, the codebook was adaptively changed and ZFBF precoding was finished by the station, according to the user's feedback information. The simulation results show that every user's average number of feedback bits is significantly reduced and a better sum rate performance with a lower feedback rate is gained. The codebook searching process is simplified and the sum rate performance is improved by this scheme successfully.

Echo cancellation based on additional signal

LI Huiya YANG Jianpo YIN Yongchao WANG Fang WANG Zhenchao

2013, 33(03):  631-634.  DOI: 10.3724/SP.J.1087.2013.00631

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An echo cancellation algorithm based on additional signal was proposed to eliminate the spatial co-channel interference of digital repeater in mobile communication network. Firstly, the paper studied the formation and characteristics of the echo, and established the model of true echo channel parameter matrix. Secondly, the single frequency sinusoidal signal was attached to the frequency spectrum hole of the base station, and the channel parameters of the estimated-echo matrix were estimated by making use of the convolution relationship of the cross-correlation function of the mixed-signal received by repeater, the transponder signal and the additional signal. Finally, the estimated-echo of the transponder signal was subtracted from the received mixed signal, which was achieved by the estimated-echo channel, in order to eliminate the echo interference. The simulation results show that the relative error of the attenuation coefficient of main path is 1.8493×10-5 in the frequency selective fading channel model of COST 207 standard. The estimated-echo can track the actual-echo better, so as to avoid self-excited phenomenon effectively.

Network and distributed techno

Wide baseline image matching for 3D objects

LI Wei SHI Zelin YIN Jian

2013, 33(03):  635-639.  DOI: 10.3724/SP.J.1087.2013.00635

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An affine invariant local feature detector has been put forward for 3D object image matching. In order to cope with view angle and scale changes, this algorithm changed the image structure to fit the circular Gaussian filter according to the principle that Gaussian filter and image structure should be compatible. Local image structures were measured by covariance matrixes of Maximally Stable Extremal Regions (MSER) having been detected in the image. Anisotropic image structures must be rotated and squeezed into isotropic image structures to guarantee the correctness of image transformation. Finally, Scale Invariant Feature Transform (SIFT) features were extracted on isotropic image structures. Coordinates of SIFT features should be changed into the original image coordinates after being extracted. The experimental results indicate that the local features extracted by this algorithm are fully affine invariant. They are suitable to be used in wide baseline image matching for 3D objects.

Medical image registration algorithm based on Powell algorithm and improved genetic algorithm

LI Chao LI Guangyao TAN Yunlan XU Xianglong

2013, 33(03):  640-644.  DOI: 10.3724/SP.J.1087.2013.00640

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Concerning the faults of local extremum in image registration based on mutual information, a new medical image registration method based on Powell and improved genetic algorithm was proposed in this paper. It put forward an improved method regarding the shortcomings of the standard genetic algorithm, such as slow convergence and prematurity that will result in artifacts, and generated the iteration individual by Logistic chaos map. This method utilized the multi-resolution analysis strategy and searched for the optimal of the objective function by this hybrid optimized algorithm in the lowest resolution image level. Then it continued the optimization course and accomplished the image registration by this optimal data with the Powell algorithm. The experimental results indicate that this algorithm can effectively improve the image registration velocity and avoid local extremum of the operator while getting better performance of image precision in contrast to the Powell algorithm and unimproved genetic algorithm.

Correlation matching recognition algorithm based on character normalized double projection

2013, 33(03):  645-647.  DOI: 10.3724/SP.J.1087.2013.00645

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Since the correct character recognition rate of the printed Uighur character recognition system is low, in this study, a character image was scanned in both horizontal and vertical directions to create a row-projection vector and a column-projection map. In combination with three levels of classification, the target character with the corresponding classification characters' double projection maps was normalized individually, and the correlation mean calculation was carried out. The maximum mean character was taken as the best match recognition result, so as to implement the Uighur character recognition. The correlation matching recognition algorithm based on character normalized double projection method has been proved by experiment that it has the advantages of strong anti-interference, simple implementation, high matching accuracy, thus improving the correct rate of the printed Uighur character recognition.

High quality ordered subset expectation maximization reconstruction algorithm based on multi-resolution for PET images

ZHANG Quan FU Xuejing LI Xiaohong GUI Zhiguo

2013, 33(03):  648-650.  DOI: 10.3724/SP.J.1087.2013.00648

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In Positron Emission Tomography (PET) imaging, Maximum Likelihood Expectation Maximization (MLEM) algorithm cannot be directly applied to clinical diagnosis due to suppressing noise ineffectively and converging slowly. Although Ordered Subset Expectation Maximization (OSEM) algorithm converges fast, it will lead to a significant decline in the quality of the reconstructed image. To address this problem, multi-resolution technology was introduced into the subset of the OSEM reconstruction algorithm to suppress noise and stabilize solving process. The experimental results indicate that the new algorithm overcomes the drawback of the traditional algorithm on degrading the reconstructed image and has the advantage of fast convergence. The proposed reconstruction algorithm can obtain a higher Signal-to-Noise Ratio (SNR) and a superior visual effect.

Object tracking by fusing multiple features based on adaptive background information

LI Rui LIU Changxu NIAN Fuzhong

2013, 33(03):  651-655.  DOI: 10.3724/SP.J.1087.2013.00651

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It is difficult for the object tracking algorithm based on single feature, to track the object in complex cases. Therefore, this paper proposed an algorithm fusing multiple features for object tracking based on adaptive background information. The algorithm was based on the use of color feature and gray level co-occurrence matrix texture feature to represent the object. Under the frame of particle filter, it analyzed the particle space distribution, particle value distribution and ability to distinguish the background information with different feature. Then it presented an efficient fusion coefficient calculation. According to the object's appearance of changes in the process of tracking, it updated the object template adaptively. The experimental results in different settings show that this algorithm greatly improves the resistance to background interference, under the premise of not reducing the real-time. In all sorts of situations, it has good stability and robustness.

Image feature extraction based on modified fast sparse coding algorithm

SHANG Li SU Pin'gang ZHOU Yan

2013, 33(03):  656-659.  DOI: 10.3724/SP.J.1087.2013.00656

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On the basis of the Fast Sparse Coding (FSC) model, considering the maximum sparse distribution of feature coefficients and the orthogonality of feature bases of an image, a Modified FSC (MFSC) model was proposed in this paper. This FSC algorithm was based on iteratively solving two convex optimization problems: L₁-norm based regularized least square problem and L₂-norm based constrained least square problem, and it can realize the learning of complete bases and overcomplete bases, as well as efficiently extract the features of images. Moreover, the convergence speed of FSC is quicker than that of Basic Sparse Coding (BSC). The images of natural scene and palmprint were used to test the property of FSC algorithm proposed by the authors in feature extraction, and then the extracted features were utilized to image reconstruction. Compared with reconstructed images obtained by BSC, the experimental results verify the validity of the modified FSC in quickly extracting image features.

Detection and location of image region duplication forgery based on phase correlation

JING Li ZHANG Huijuan

2013, 33(03):  660-662.  DOI: 10.3724/SP.J.1087.2013.00660

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Most existing algorithms for detecting region duplication forgery are of low efficiency. Concerning this problem, this paper proposed a detecting and locating algorithm based on phase correlation. Firstly, the image was divided into small blocks by the means of sliding window. It skipped multi-pixels every time. Those blocks that had more matching possibility were chosen through sorting grayscale mean of block. Secondly, whether two blocks were matched was decided and their relative translation was calculated using the impulse function peak of the cross-power spectrum. Lastly, the mismatched blocks got removed according to the number of matched blocks that had same offset distance, and the forgery regions were marked according to the matched blocks. The experimental results show that the proposed algorithm is efficient and robust to such operations as lossy compression, blur filter and noise.

JPEG steganalysis based on parallel feature fusion by quaternion

HE Fengying ZHONG Shangping YANG Jian

2013, 33(03):  663-666.  DOI: 10.3724/SP.J.1087.2013.00663

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Feature fusion has become a heated research topic in steganalysis. In order to solve the problems in the existing feature fusion methods, such as feature dimension disaster in serial feature fusion method and only two kinds of features can be integrated in parallel feature fusion method, this paper proposed a JPEG steganalysis approach based on parallel feature fusion by quaternion. The method firstly selected the four fusion features, and then isolated redundant components by the Principal Component Analysis (PCA), finally combined four features as quaternion vector to achieve multi-feature parallel fusion using the four components of the quaternion. The experimental results show that, compared with the traditional feature fusion method, the proposed method effectively improves the detection rate of steganalysis in JPEG images, and has better robustness.

Algorithm of near-duplicate image detection based on Bag-of-words and Hash coding

WANG Yutian YUAN Jiangtao QIN Haiquan LIU Xin

2013, 33(03):  667-669.  DOI: 10.3724/SP.J.1087.2013.00667

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To solve the low efficiency and precision of the traditional methods, a near-duplicate image detection algorithm based on Bag-of-words and Hash coding was proposed in this paper. Firstly, a 500-dimensional feature vector was used to represent an image by Bag-of-words; secondly, feature dimension was reduced by Principal Component Analysis (PCA) and Scale-Invariant Feature Transform (SIFT) and features were encoded by Hash coding; finally, dynamic distance metric was used to detect near-duplicate images. The experimental results show that the algorithm based on Bag-of-words and Hash coding is feasible in detecting near-duplicate images. This algorithm can achieve a good balance between precision and recall rate: the precision rate can reach 90%-95%, and entire recall rate can reach 70%-80%.

Image thresholding segmentation based on human vision model and maximum between-cluster variance

ZOU Xiaolin FENG Guocan

2013, 33(03):  670-673.  DOI: 10.3724/SP.J.1087.2013.00670

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Because the area division of the traditional two-dimensional histogram has such shortcomings as part of the target points and background points are divided into edge points or noise points, while part of the edge points and noise points are divided into the target point and background points and the traditional two-dimensional image thresholding segmentation algorithms' time complexity are high, a new two-dimensional histogram was proposed by using human vision model, and a new region division method was proposed to the proposed histogram, and at the same time, the proposed histogram was applied to image thresholding segmentation based on maximum between-cluster variance. According to segmentation time, misclassification error and uniformity, a series of experiments were carried out to show the proposed algorithm reduces the time complexity and has good segmentation performance compared with several typical two-dimensional threshold segmentation algorithms.

Fast image edge detection algorithm based on multidirectional gradient edge detection predictor

DANG Xiangying BAO Rong JIANG Daihong

2013, 33(03):  674-676.  DOI: 10.3724/SP.J.1087.2013.00674

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By using Gradient Adjusted Predictor (GAP) and Gradient Edge Detection (GED) predictors of lossless image encoding for reference, with an improved one, a new image edge detection algorithm of the dynamic threshold control based on Multidirectional Gradient Edge Detection Predictor (MGEDP) template was proposed. The image was cut into four equal parts, and these parts would be executed simultaneously by MGEDP template in different direction of four opposite ways to calculate the error values by the parallel technology. From these feedback values, the algorithm created error image, calculated the threshold values by Otsu algorithm, classified the edges of error image, thinned the edges, and composed the last edge image. The experimental results show that the algorithm using parallel technology not only decreases the time complexity, but also gets the clearer edges, more details, and better visual image.

Texture feature recognition based on Contourlet transform and support vector machine

WANG Jiayi GE Yurong

2013, 33(03):  677-679.  DOI: 10.3724/SP.J.1087.2013.00677

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How to identify the most appropriate feature vector is the key of image texture recognition. Considering the characteristics of Contourlet transform, the image was transformed from the spatial domain to the frequency domain. The feature vectors of low-frequency subband, medium-frequency subband and high-frequency subband were extracted comprehensively and entered to Support Vector Machine (SVM) for classification. Brodatz database was used for simulation. The experimental results demonstrate that mean and variance of low frequency and the energy of high frequency are the optimal representation of the image texture. They are combined to make the recognition accuracy rate up to 98.75% and the vector dimension is lower.

Average bit-rate algorithm optimization for rate control of X264

TIAN Yishu SHEN Qiang LIU Yanwei ZHANG Yu ZHAO Zhijun

2013, 33(03):  680-683.  DOI: 10.3724/SP.J.1087.2013.00680

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In wireless video transmission system, the network bandwidth is often limited and changing, which leads to poor quality and instability of the video information in this process. Therefore, a rate control regulation was needed in the video codec. In order to make up for the deficiency of Average Bit-Rate (ABR) algorithm in X264, two methods were proposed in this article. According to the gap between actual output bits and target ones, one is a new compensation algorithm in the frame layer to adjust the Quantization Parameters (QP) of the current frame and the other is to rewrite the growth function of the buffer to control its excessive growth. These two methods have been evaluated with different target bits but the same video sequence, and with different video sequences but the same target bits, respectively. The results show that actual output bit rate is closer to the target one on condition that the average Peak Signal-to-Noise Ratio (PSNR) stays the same.

Deformation method based on deformable model with non-linear finite element

LI Zhiwei LIU Mingjun LIU Teng'ao ZHAO Xiuyang

2013, 33(03):  684-687.  DOI: 10.3724/SP.J.1087.2013.00684

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The deformation of 3D models is one of the hot issues of computer graphics and other cross-discipline research. In view of the artificially using the linear strain on the model deformation, the authors proposed an effective model deformation approach. First, the original model was simplified through geometric delete method and the simplified models stayed as the form of the original model. Then, using the tetrahedron subdivision, the tetrahedral model was deformed by adopting the Green strain. Finally, the experimental results between linear strain and non-linear strain were presented in detail. The result also demonstrates that first simplifying the models then generating the tetrahedron, the simulation rate could be increased.

Algorithm of generating multi-resolution curves for progressive transmission over the Internet

CAO Zhenzhou LI Manchun CHENG Liang CHEN Zhenjie

2013, 33(03):  688-690.  DOI: 10.3724/SP.J.1087.2013.00688

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Concerning the problems of high time complexity and topological inconsistency existing in the multi-resolution representation of curve for progressive transmission, an algorithm of generating multi-resolution curves for progressive transmission over the Internet was proposed in this paper. By using pre-stored vertex deviation to simplify curves and using an optimized monotone chain intersection algorithm to maintain topological consistency, the algorithm can quickly generate topologically consistent multi-resolution curves. The algorithm was used in the experiment of progressive transmission for curve data, and the experimental results show that the multi-resolution curve data maintain topological consistency and the generation time changes linearly with the amount of data. The effectiveness of the algorithm has been verified in the experiment.

New no-reference image quality assessment method based on decomposition of gradient similarity

LIAO Yu GUO Li

2013, 33(03):  691-694.  DOI: 10.3724/SP.J.1087.2013.00691

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At present, the existing general no-reference image quality assessment methods are used for special purpose. Furthermore, the distortion type of the image is unknown in practical application. Most of no-reference image quality assessment methods are based on the geometrical description feature of image, but this type of method relies on the boundary of image too much. To solve this problem, a no-reference image quality assessment method was proposed based on the gradient similarity decomposition of image, which was named Decomposition of Gradient Similarity (DGS). The proposed method extracted the gradient feature and decomposed the correlation of gradient as the main structure information of the image. The experimental results show that the proposed DGS model is better than Peak Signal-to-Noise Ratio (PSNR) (or Mean Square Error (MSE)) model, which is more sensitive to Human Visual System (HVS) characteristics and more consistent to the subjective evaluation value.

Face description and recognition by sequence of Gabor pyramid with change in age

XU Fengjiao WANG Guoyin

2013, 33(03):  695-699.  DOI: 10.3724/SP.J.1087.2013.00695

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Facial feature change occur in varying degrees with the increase of age. These features involve the shape features and texture features, which increase the difficulty of face recognition. In order to accurately describe the facial features with change in age to improve the accuracy of face recognition, firstly, this paper applied the innovation of Gabor wavelet on the pyramid model to structure the Gabor pyramid characteristic sequence. This paper used mean grid to descend and denoise the Gabor pyramid characteristic sequence initially, and then reconstructed pyramid characteristic sequence of different samples at the same level and direction. Finally, this paper constructed forty parallel classifiers to classify by using Direct Fractional-step Linear Discriminant Analysis (DF-LDA) algorithm. The experimental results show that the Gabor pyramid characteristic sequence can improve the accuracy of face recognition with the change in age.

Face recognition with adaptive local-Gabor features based on energy

ZHOU Lijian MA Yanyan SUN Jie

2013, 33(03):  700-703.  DOI: 10.3724/SP.J.1087.2013.00700

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Concerning the time-consuming and computational complexity in extracting face features of traditional Gabor filters, the face features were extracted by using three different local Gabor filters adaptively chosen by the Gabor images' energy from different directions, scales and overall situation. Firstly, the Gabor features of some images in the face database were extracted and analyzed, and the local Gabor filters were built by choosing the filters corresponding to the images with larger energy. And then, the Fisher features were extracted using Linear Discriminate Analysis (LDA) further. Finally, face recognition was realized using the nearest neighbor method. The experimental results based on ORL and YALE face database show that the proposed approach has better face recognition performance with less feature dimension and calculation time.

Fire image features selection and recognition based on rough set

HU Yan WANG Huiqin QIN Weiwei ZOU Ting LIANG Junshan

2013, 33(03):  704-707.  DOI: 10.3724/SP.J.1087.2013.00704

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Concerning the contradiction of accuracy and real-time in image fire detection, a fire image features selection and recognition algorithm based on rough set was proposed. Firstly, through in-depth study on the flame image features, the top edge of flame driven by the combustion energy is very irregular, and obvious vibration phenomenon occurres. But the lower edge is the opposite. Based on this feature, the upper and lower edges of the jitter projection ratio can be used as a flame from the edge shape regular interference. Then, the six striking flame features were chosen in order to create training samples. When fire classification ability was not affected, the feature classification table gained by experiment was used to reduce attributes of the training samples. And the reduced information systems attributes were applied to train a support vector machine model, and the fire detection was realized. Finally, this fire detection algorithm was compared to the traditional Support Vector Machine (SVM) fire detection algorithm. The results show that the presented algorithm reduces redundant attributes, eliminates the dimension of fire image features space, and decreases the data of training and testing in classifier in case rough set as a SVM classifier prefix system. While ensuring recognition accuracy, the algorithm improves fire detection speed.

Detection of offshore ship and well platform based on optical remote sensing images

MENG Ruolin XING Qianguo

2013, 33(03):  708-711. 

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To improve situations as follows: in the strategies of offshore ship and well platform detection, most masks of sea zones use non-real time shoreline database; targets seeking algorithms lack capability of searching targets in large scale images, a strategy of ship and well platform detection based on optical remote sensing images was proposed. The strategy included building masks of sea zones using morphological operations, determining decision algorithms of targets' existence, and extracting targets' locations based on iterative optimal Threshold Segmentation (TS) in Sliding Windows (SW). Parameters in the decision algorithm and the size of sliding window were analyzed, and the corresponding results were cross validated with that of artificial visual interpretation. The experimental results prove that the absolute accuracy of targets extraction arrives 0.981 while relative accuracy of targets extraction arrives 0.954 with proper parameters set. This strategy shows practical value.

Information security

Distributed multilevel security core architecture based on noninterference theory

SHAO Jing CHEN Xingyuan DU Xuehui CAO Lifeng

2013, 33(03):  712-716.  DOI: 10.3724/SP.J.1087.2013.00712

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To improve the correctness and feasibility of the implementation of multilevel security in the distributed environment, a distributed multilevel security core architecture — Distributed Trusted Computing Base (DTCB) was proposed. DTCB was divided into three layers, TCB of System layer, TCB of Module layer and TCB of Partition layer, finer multilevel control granularity was realized step by step, greatly reducing the complexity of the implementation of multilevel security in the distributed environment. At last, based on the composable noninterference model, the security of DTCB was formally proved. The result shows that DTCB assures the multilevel security of distributed system as a whole.

Cross domain reference monitor and its data-centered multilevel security model

LI Hongmin WAN Pingguo GE Yang

2013, 33(03):  717-719.  DOI: 10.3724/SP.J.1087.2013.00717

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A new cross domain reference monitor and Multi-Level Security (MLS) model were proposed for a trusted MLS system. The model was based on Commercial Off-The-Shelf (COTS) products like commercial computers and security compliant hardware devices. System high networks were properly connected with reference validation computer by trusted one-way transfer devices (EAL7) for data-centric MLS model. The model allowed information to flow from low domain to high domain, and allowed sanitization data with low label to flow from high domain to low domain, but data without low label were prohibited to flow from high domain to low domain. The model was applied to the information system of classification protection. Formal verification of security model and policy demonstrates it is feasible for a MLS system with COTS products and trusted hardware devices.

Multidimensional timing trust degree rank model based on multiple attribute decision-making

GAO Jianxin WU Xiaoping QIN Yanlin WANG Jiasheng

2013, 33(03):  720-722.  DOI: 10.3724/SP.J.1087.2013.00720

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Concerning the trust degree rank question of which attribute weights are unknown and data are multidimensional, a trust degree rank method based on linear programming theory was proposed. Firstly, the proposed method used linear programming model to make sure the trust degree rank ceiling-floor vector of nodes under the condition of one-dimensional data and unknown attribute weights, and then built the optimal coordinating rank model under multidimensional timing, and then converted the model to the classical assignment problem, and used the Hungary algorithm to solve the model, at last the trust degree rank of each node was obtained. The example analysis shows that, when the optimal coordinating rank model distance parameter q takes low value, the extreme data are not sensitive to the model, the proposed model can prevent evaluation error caused by a few mutation data; when q takes high value, the extreme data are sensitive to the model, the proposed model can identify the potential dishonest evaluation objects of a swing trust degree.

Immune detector distribution optimization algorithm with Monte Carlo estimation

LIU Hailong ZHANG Fengbin XI Liang

2013, 33(03):  723-726.  DOI: 10.3724/SP.J.1087.2013.00723

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In order to avoid lots of holes among mature immune detectors and deal with the problem of boundary invasion in intrusion detection, analyzing the relationship between number of detectors and detection performance, a detector distribution optimization algorithm with Monte Carlo estimation was proposed: evaluating the coverage of detectors by the Monte Carlo method, and updating the detector set by the offspring to improve detectors' distribution. The experimental tests demonstrate that the algorithm can not only decrease the holes but also achieve a more precise coverage of the nonself space with fewer detectors, and increase the detector's detection performance.

Detection method of anomaly traffic state based on artificial bee colony

DUAN Moyi

2013, 33(03):  727-729.  DOI: 10.3724/SP.J.1087.2013.00727

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In order to deal with the worsening network security problem, a new state detection algorithm, detection method of Anomaly traffic State based-Artificial bee colony (DASA), was proposed by Artificial Bee Colony (ABC) and clustering. In this algorithm, the anomaly traffic model was presented with SKETCH and Hash function at first, and the anomaly state was detected based on ABC. Then, a simulation with actual data is conducted to compare the results between Sample and DASA, which shows that DASA has better adaptability. And it has large impact on state detection with clustering number, dropping threshold and domain radius.

HDFS optimization program based on GE coding

ZHU Yuanyuan WANG Xiaojing

2013, 33(03):  730-733.  DOI: 10.3724/SP.J.1087.2013.00730

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Concerning Hadoop Distributed File System (HDFS) data disaster recovery efficiency and small files, this paper presented an improved solution based on coding and the solution introduced a coding module of erasure GE to HDFS. Different from the multiple-replication strategy adopted by the original system, the module encoded files of HDFS into a great number of slices, and saved them dispersedly into the clusters of the storage system in distributed fashion. The research methods introduced the new concept of the slice, slice was classified and merged to save in the block and the secondary index of slice was established to solve the small files issue. In the case of cluster failure, the original data would be recovered via decoding by collecting any 70% of the slice, the method also introduced the dynamic replication strategies, through dynamically creating and deleting replications to keep the whole cluster in a good load-balancing status and settle the hotspot issues. The experiments on analogous clusters of storage system show the feasibility and advantages of new measures in proposed solution.

Generalized function projective lag synchronization of a class of hyperchaotic systems with fully uncertain parameters

CHAI Xiuli WU Xiangjun

2013, 33(03):  734-738.  DOI: 10.3724/SP.J.1087.2013.00734

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Chaos synchronization is the essential theoretical basis of chaotic secure communication. Since time delay of function projective synchronization had rarely been considered, the adaptive controllers and parameter update laws were designed based on Lyapunov stability theory and adaptive control method, and generalized function projective lag synchronization of a class of hyperchaotic system was achieved. Then, taking hyperchaotic Lorenz-Stenflo (LS) system and hyperchaotic Lü system with fully uncertain parameters as an example the correctness and effectiveness of the method was varified, and the influence of external disturbance and time delay on the effect of the synchronization control were studied. The numerical simulations show the effectiveness, feasibility and robustness of the proposed method.

SIRS model of computer virus propagation based on two-stage immunization

YE Xiaomeng YANG Xiaofan

2013, 33(03):  739-742.  DOI: 10.3724/SP.J.1087.2013.00739

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For the deficiency of the existing network virus models with immunization, considering the infectious disease model in biology, a Susceptible-Infected-Recovered-Susceptible (SIRS) computer virus propagation model with stage immunization was formulated. The varying probability of being vaccinated when the threshold was reached and its impact on the spread of the virus in the network were considered. Furthermore, with the help of the theory of dynamic stability analysis, the existence and stability conditions of equilibriums were studied. The numerical simulation results illustrate that improving the rate of vaccination and setting a reasonable threshold can effectively constrain virus prevalence in the network.

Agent-based provable data possession scheme for mobile cloud computing

YANG Jian WANG Jian WANG Haihang YANG Dengqi

2013, 33(03):  743-747.  DOI: 10.3724/SP.J.1087.2013.00743

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The existing Provable Data Possession (PDP) schemes cannot be directly applied in mobile cloud computing because the terminal' storage space and computing power are limited for the computationally intensive operations in those schemes. Addressing this issue, an Agent-based PDP scheme was proposed for mobile cloud computing. A semi-trusted security computation Agent was introduced between the terminal and the cloud server in order to help end-users complete the computationally intensive operations, so that the PDP scheme can be applied in mobile computing. A concrete PDP scheme was presented and a formal proof shows it satisfies the Chosen Plaintext Attack (CPA) security under random oracle model. The quantitative analysis results show that the scheme is fit for mobile cloud computing.

Digital watermarking algorithm of anti-geometric attacks based on SIFT

GAO Huming LI Kaijie WANG Yingjuan

2013, 33(03):  748-751.  DOI: 10.3724/SP.J.1087.2013.00748

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To solve the problems that the digital watermark information are vulnerable to geometric attacks and the balance between invisibility and robustness of watermarking algorithm, a digital watermarking algorithm was proposed based on Scale Invariant Feature Transform (SIFT) for image local feature points. Based on SIFT algorithm local feature points, circular Local Feature Area (LFA) that met certain conditions were found. After the LFA regularization, the watermarking was embedded in intermediate frequency coefficient of LFA Discrete Cosine Transform (DCT) domain. Among them, considering the influence of the watermark information on the image quality, the embedding strength was dynamically adjusted according to the Watson human visual model. The experimental results show that the Peak Signal-to-Noise Ratio (PSNR) and the similarity of watermark get higher. The algorithm guarantees better watermark invisibility and robustness performance under certain geometric attacks.

Digital hologram watermarking based on discrete Fourier transform

WU Qingle PENG Daiyuan

2013, 33(03):  752-755.  DOI: 10.3724/SP.J.1087.2013.00752

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A print-scan resilient watermarking algorithm based on digital hologram was studied in this paper. A hologram image of two watermark was embedded into the amplitude of middle spectral magnitude of the host image, and the same replacement was done in the central semmetry block. A Peak Signal-to-Noise Ratio (PSNR) threshold adapted to the texture of the host image was set to adjust the watermark shrength. The proposed approach shows advantages in invisibility, robustness, embedding capacity, resistance against the attack of scaling, noise, and JPEG compression. The watermark can be extracted from the watermarked image after print-scan.

Design of digital watermark extraction system based on FPGA

WANG Shasha GAO Fei WEN Yingxin YU Jing

2013, 33(03):  756-758.  DOI: 10.3724/SP.J.1087.2013.00756

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To solve the problem that software implementation cannot meet real-time requirements, a hardware scheme based on Field-Programmable Gate Array (FPGA) was presented. By analyzing the digital watermark extraction system, a watermark-embedding algorithm suitable for FPGA implementation was designed and its structure is applicable to 5/3 wavelet transform. Moreover, a new watermark extraction structure that corresponded to the embedding algorithm was also proposed. The pipeline and highly parallel structure has the features of high computation efficiency, small size, low-power and real-time process. The simulation results demonstrate the system's correctness and the algorithm's abroad applicability.

Efficient certificate-based signature scheme with strong designated verifier

ZHAI Zhengyuan GAO Dezhi LIANG Xiangqian PAN Shuai

2013, 33(03):  759-761.  DOI: 10.3724/SP.J.1087.2013.00759

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Concerning the flaw that it needs a fully credible third party in ID-based strong designated verifier signature and the low efficiency of existing schemes, taking the advantage of Certificate Authority (CA)'s low trust level in certificate-based public key cryptography, a new strong designated verifier signature scheme was proposed in this paper. Furthermore, the formal security analysis under assumed Bilinear Diffie-Hellman (BDH) problem in the random oracle model was presented. Performance analysis shows the scheme meets all properties of strong designated verifier signature schemes and enjoys higher correspondence efficiency used in bandwidth limited environment since the signature length is just one of the group elements.

Cryptanalysis and improvement of ID-based partially blind signature scheme

HE Junjie SUN Fang QI Chuanda

2013, 33(03):  762-765.  DOI: 10.3724/SP.J.1087.2013.00762

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The cryptanalysis of the ID-based partially blind signature scheme proposed by Li et al. (LI M X, ZHAO X M, WANG H T. Security analysis and improvement of a partially blind signature scheme. Journal of Computer Applications, 2010, 30(10): 2687-2690) showed that the signature requester could change the negotiated information illegally. Therefore, an improved partially blind scheme was purposed to resist the tampering negotiated information attacks. The new scheme was proved to be existentially unforgeable against adaptive chosen message and identity attacks in random oracle model. Compared with other ID-based partially blind signature schemes, the new scheme has higher computational efficiency.

Artificial intelligence

Unipolar Sigmoid neural network classifier based on weights and structure determination method

ZHANG Yunong CHEN Junwei LIU Jinrong QU Lu LI Weibing

2013, 33(03):  766-770.  DOI: 10.3724/SP.J.1087.2013.00766

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A neural network classifier with the hidden neurons activated by unipolar Sigmoid function was constructed and investigated in this paper. The thresholds of hidden neurons and weights between the input layer and the hidden layer of the neural network were randomly generated. The psedoinverse-type Weights Direct Determination (WDD) method was applied to determining the weights between the hidden layer and the output layer. Moreover, a Structure Automatic Determination (SAD) algorithm with pruning-while-growing and twice-pruning policies was proposed to determine the optimal structure of the neural network. The numerical experimental results demonstrate that the SAD algorithm can determine the optimal structure of the neural network quickly and effectively and the neural network classifier has a satisfactory performance.

Reasoning of ontology model for typhoon disasters domain based on Jena

HUANG Fenghua YAN Luming

2013, 33(03):  771-775.  DOI: 10.3724/SP.J.1087.2013.00771

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Some problems exist in the traditional typhoon disasters prediction, such as depending mainly on statistical methods, lack of semantic-driven processes and intelligent reasoning. In order to solve these problems, a reasoning mechanism of the ontology model of typhoon disasters domain based on Jena was proposed. Firstly, the ontology model of typhoon disasters domain expressed by Web Ontology Language (OWL) was built based on analyzing the impact factors and evolution history of the typhoon disasters fully. Secondly, the Jena reasoning engine and custom rules were used for the reasoning of typhoon disasters ontology model and mining the hidden impact factors of typhoon disasters or the information of disaster chains. Finally, an Ontology-driven Typhoon Disasters Expert System (Onto-TDES) was built. The experimental results show that the mechanism can solve the lack of semantic-driven processes and intelligent reasoning preliminarily, and improve the intelligent level of the management and prediction of the typhoon disasters.

Method of Deep Web entities identification based on BP neural network

XU Hongyan DANG Xiaowan FENG Yong LI Junping

2013, 33(03):  776-779.  DOI: 10.3724/SP.J.1087.2013.00776

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To solve the problems such as low level automation and poor adaptability of current entity recognition methods, a Deep Web entity recognition method based on Back Propagation (BP) neural network was proposed in this paper. The method divided the entities into blocks first, then used the similarity of semantic blocks as the input of BP neural network, lastly obtained a correct entity recognition model by training which was based on the autonomic learning ability of BP neural network. It can achieve entity recognition automation in heterogeneous data sources. The experimental results show that the application of the method can not only reduce manual interventions, but also improve the efficiency and the accuracy rate of entity recognition.

Disambiguation of domain word segmentation based on unsupervised learning

XIU Chi SONG Rou

2013, 33(03):  780-783.  DOI: 10.3724/SP.J.1087.2013.00780

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Domain word segmentation is much more difficult than general word segmentation in Chinese natural language processing. The segmentation ambiguity has been lack of effective solution especially. Concerning this problem, an unsupervised learning method for domain segmentation ambiguity was proposed. String frequency, mutual information and boundary entropy were selected as evaluation standard for segmentation ambiguity. Individual and combination of these three kinds of information were used to solve the problem. The experimental results suggest that the proposed can solve the domain segmentation ambiguity efficiently and effectively.

Parallel realization of focus and interrogative meaning in intonation of Uyghur

Tursun QADIR WANG Bei

2013, 33(03):  784-788.  DOI: 10.3724/SP.J.1087.2013.00784

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With a controlled experiment, the co-encoding of interrogative meaning and focus on Uyghur intonation was systematically investigated. The results show that focus has effects on both pitch and duration of an interrogative sentence: 1) On-focus words exhibit F0 increase and pitch range expansion, post-focus words maintain high F0, while pre-focus words leave F0 largely intact. 2) An important feature of interrogative intonation is the significant F0 rising in sentence final syllable. Besides, the intonation after a focused word in question is distinctly higher than that in statement. 3) Duration of on-focus words is lengthened, while pre-focus and post-focus words do not show obvious duration variation. 4) Compared with statement, sentence duration of question is longer, which is mainly manifested as the lengthening of sentence final syllable. In summary, Uyghur, like Chinese and English, supports Parallel Encoding and Target Approximation (PENTA) intonation model. However, the three languages display different ways of post-focus intonation manipulation in questions.

Imbalanced data learning based on particle swarm optimization

CAO Peng LI Bo LI Wei ZHAO Dazhe

2013, 33(03):  789-792.  DOI: 10.3724/SP.J.1087.2013.00789

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In order to improve the classification performance on the imbalanced data, a new Particle Swarm Optimization (PSO) based method was introduced. It optimized the re-sampling rate and selected the feature set simultaneously, with the imbalanced data evaluation metric as objective function through particle swarm optimization, so as to achieve the best data distribution. The proposed method was tested on a large number of UCI datasets and compared with the state-of-the-art methods. The experimental results show that the proposed method has substantial advantages over other methods; moreover, it proves that it can effectively improve the performance on the imbalanced data by optimizing the re-sampling rate and feature set simultaneously.

Team task allocation method for computer generated actor based on game theory

ZHENG Yanbin TAO Xueli

2013, 33(03):  793-795.  DOI: 10.3724/SP.J.1087.2013.00793

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For the complex tasks with time constraints, which can dynamically be added to environment, a task allocation model based on game theory was established, and a task allocation method was proposed, which made Computer Generated Actor (CGA) be able to choose its actions according to the local information owned by itself, and ensured that CGA learned a strict pure strategy Nash equlilibrium quickly by using fictitious play method on behavior coordination. The simulation results show that this method is reasonable, and it can effectively solve the dynamic task allocation problem.

Chaos-based dynamic population firefly algorithm

FENG Yanhong LIU Jianqin HE Yichao

2013, 33(03):  796-799.  DOI: 10.3724/SP.J.1087.2013.00796

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The Firefly Algorithm (FA) has a few disadvantages in the global searching, including slow convergence speed, low solving precision and high possibility of being trapped in local optimum. A FA based on chaotic dynamic population was proposed. Firstly, chaotic sequence generated by cube map was used to initiate individual position, which strengthened the diversity of global searching; secondly, through dynamic monitoring of population, whenever the algorithm meets the preset condition, the new population individuals were generated using chaotic sequences, thus effectively improving convergence speed; thirdly, a Gaussian disturbance would be given on the global optimum of each generation, thus the algorithm could effectively jump out of local minima. Based on six complex test functions, the test results show that chaos-based dynamic population FA improves the capacity of global searching optimal solution, convergence speed and computational precision of solution.

Algorithms for approximate pattern matching with wildcards and length constraints

HUANG Guolin GUO Dan HU Xuegang

2013, 33(03):  800-805.  DOI: 10.3724/SP.J.1087.2013.00800

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Current works on the Approximate Pattern Matching with Wildcards and Length constraints (APMWL) problem can only cope with replacement operation. This paper proposed an Edit Distance Matrix (EDM) method based on dynamic programming and the Approximate Pattern Matching with EDM (APM) algorithm. APM can handle all approximate operations including insertion, replacement and deletion. Moreover, this paper extended APM to the APM-OF algorithm with a strict constraint condition that each character can be used at most once for pattern matching in a sequence. The experiments verify that both APM and APM-OF have significant advantages on matching solutions against other peers. The average improvement rates of matching compared to SAIL-Approx are up to 8.34% and 12.37% respectively. It also demonstrates an advantage on approximate pattern mining that the number of approximate patterns mined by APM-OF is 2.07 times of that mined by OneoffMining.

Gravitational search algorithm based on feedback mechanism and its application in SVM

GU Binjie PAN Feng

2013, 33(03):  806-809.  DOI: 10.3724/SP.J.1087.2013.00806

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To overcome premature problem of high-dimensional multimodal function in the optimization process by Standard Gravitational Search Algorithm (SGSA), a new Gravitational Search Algorithm based on Feedback mechanism (FGSA) was proposed. Considering the large loss in population diversity during the evolution process, the distance to the optimum position and the distance to its nearest neighbor were introduced into the proposed algorithm to balance the trade-off between exploration and exploitation ability. Mutation operation was also embedded into FGSA. The test results of four benchmark functions demonstrate that FGSA has much better stability and accuracy than SGSA in finding global optimum. Furthermore, when FGSA is applied to Support Vector Machine (SVM) classification, suitable feature subsets and SVM parameters can be effectively found out, and better classification results will be obtained.

Convergence analysis of improved clonal selection algorithm

ZHENG Xianhua LUO Yanmin

2013, 33(03):  810-813.  DOI: 10.3724/SP.J.1087.2013.00810

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In order to improve Clonal Selection Algorithm (CSA) and make it theoretically mature, this paper adopted two random convergence measures: complete convergence and mean convergence to do the convergence analysis for the proposed algorithm named improved clonal Selection Algorithm for Multi-class Classification (Multi_CSA). It demonstrated that the Multi_CAS satisfied the sufficient condition for convergence to a global optimal solution. An experiment was also performed to validate the result.The paper proves that Multi_CAS meets the sufficient condition for convergence.The experiment shows that the algorithm will converge after several generations.It is concluded that Multi_CSA can converge within limited generation and it is a relatively mature algorithm.

Network and distributed techno

Survey on evolutionary models of protein-protein interaction network

LUO Jiawei LIANG Cheng SONG Dan LI Guanghui

2013, 33(03):  816-820.  DOI: 10.3724/SP.J.1087.2013.00816

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The research on the evolutionary mechanisms and models of Protein-Protein Interaction (PPI) network is significant for understanding the evolution of the biological systems as well as the formation process of the organisms. So far, there have been kinds of models based on different evolutionary mechanisms. All of these models exhibit certain topological characteristics emerging from the protein-protein interaction networks, while some limitations exist simultaneously. This paper focused on several classic protein-protein interaction network models, analyzing the main ideas of these models and comparing the topological characteristics derived from them with those of real protein-protein interaction networks. A summary of the features for each model was given based on the experiments. At last, several viewpoints for the future research of protein-protein interaction network models were also proposed to provide a useful reference for further studies.

Communication-efficient parallel sorting integers sequence on multi-core cluster

KE Qi ZHONG Cheng CHEN Qingyuan LU Xiangyan

2013, 33(03):  821-824.  DOI: 10.3724/SP.J.1087.2013.00821

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A data distribution strategy and a communication-efficient parallel algorithm for sorting integers sequence were proposed on the heterogeneous cluster with multi-core machines. The presented data distribution model properly utilized different computation speed, communication rate and memory capacity of each computing node to dynamically compute the size of the data block to be assigned to each node to balance the loads among nodes. In the proposed parallel sorting algorithm, making use of the characteristic of integers sequence, master node distributed the data blocks to the salve nodes and received the sorted subsequences with two-round mode, each salve node returned its sorted subsequence to master node by bucket-packing method, and master node linked its received sorted subsequences to form directly a final sorted sequence by the bucket mapping in order to reduce the data merge operations with large communication cost. The analysis and experimental results on the heterogeneous cluster with multi-core machines show that the presented parallel sorting integers sequence algorithm is efficient and scalable.

GPU-based preconditioned conjugate gradient method for solving sparse linear systems

ZHANG Jianfei SHEN Defei

2013, 33(03):  825-829.  DOI: 10.3724/SP.J.1087.2013.00825

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A GPU-accelerated preconditoned conjugate gradient method was studied to solve sparse linear equations. And the sparse matrix was stored in the Compressed Sparse Row (CSR) format. The programmes were coded on Compute Unified Device Architecture (CUDA) and tested on the device of nVidia GT430 GPU. According to the features of conjugate gradient method, strategies were investigated to optimize the sparse matrix vector multiplication and the data transfer between CPU and GPU. Compared with the implementation calling cusparseDcsrmv, the self-developed kernel code of sparse matrix vector multiplication can go to a speed-up of 2.1 in the best case. Equipped with this kernel, the preconditioned conjugate gradient code obtains a maximum speed-up of 7.4 against the CPU code, which is a bit advantageous over that using CUBLAS library and CUSPARSE library.

Fleet elastic load balancing mechanism in cloud environment

DU Yao GUO Tao CHEN Junjie

2013, 33(03):  830-833.  DOI: 10.3724/SP.J.1087.2013.00830

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In order to overcome the defects of traditional rigid load balancing mechanism that it can not adapt to changing network environment, and to solve the problem of load balancing mechanisms in cloud environment that it can not take full advantage of elastic characteristics and Quality of Service (QoS) would be unstable, this paper proposed a new load balancing mechanism in cloud environment based on green computing resource pool strategy. It quantified the load according to the utilization rate of system resources and the quantization decided distribution of virtual machines. On the basis of the use of the virtual machines, resources would be recycled to improve resource utilization. The experimental results show that the response time stablizes around 2.5 seconds, the overall QoS has been obviously improved with the power consumption reduced, and the effectiveness of the mechanisms has been verified.

Collaborative filtering recommendation algorithm based on filling and similarity confidence factor

HAO Liyan WANG Jing

2013, 33(03):  834-837.  DOI: 10.3724/SP.J.1087.2013.00834

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In order to improve the recommendation quality of recommendation system when the data are sparse, an improved collaborative filtering algorithm was proposed. Using a data mining algorithm, the sparse rating matrix was filled firstly. Afterwards user-similarities and their confidence factors were calculated using the complete filling matrix. Ultimately, the recommendation forecast was made. Comparative experiments on typical dataset show that the algorithm is able to achieve better results even with extremely sparse data.

Application of cooperative filtering in categories recommendation of Chinese Wikipedia

WANG Jing HE Tingting Yimamu'aishan ABUDOULIKEMU

2013, 33(03):  838-840.  DOI: 10.3724/SP.J.1087.2013.00838

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Collaborative filtering was applied to automatically recommend categories for a Chinese Wikipedia article. Four typical semantic features namely incoming link, outgoing link, incoming link categories and outgoing link categories, were adopted to represent articles. Among all the categories of articles similar to target article, several most similar categories were chosen as the recommendation results to the target article, via calculating the similarity value between them. The experimental results show that the four semantic features have efficient performance in Wikipedia article representation. And the collaborative filtering method is also proved to be effective in recommending proper categories for Chinese Wikipedia articles.

Collaborative recommendation method improvement based on social network analysis

FENG Yong LI Junping XU Hongyan DANG Xiaowan

2013, 33(03):  841-844.  DOI: 10.3724/SP.J.1087.2013.00841

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Collaborative recommendation is widely used in E-commerce personalized service. But the existing methods cannot provide high level personalized service due to sparse data and cold start. To improve the accuracy of collaborative recommendation, a collaborative recommendation method based on Social Network Analysis (SNA) was proposed in this paper by using SNA to improve the collaborative recommendation methods. The proposed method used SNA technology to analyze the trust relationships between users, then quantified the relationships as trust values to fill the user-item matrix, and used these trust values to calculate the similarity of users. The effectiveness of the proposed method was verified by the experimental analysis. Using trust values to expand the user-item matrix can not only solve the problem of sparse data and cold start effectively, but also improve the accuracy of collaborative recommendation.

Immune genetic algorithm based on clonal selection and its application to 0/1 knapsack problem

WU Huihong QIAN Shuqu XU Zhidan

2013, 33(03):  845-848.  DOI: 10.3724/SP.J.1087.2013.00845

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There are some problems such as slow convergence and easy stagnation in local optima when using Genetic Algorithms (GA) to solve high-dimensional knapsack problem. To overcome those shortcomings, a bio-inspired clonal selection immune genetic algorithm was developed to solve knapsack problem with high dimension. In the algorithm, the antibody was binary coded and the affinity of antibody was designed based on its density; in addition, the population was divided into feasible and infeasible population, and the feasible antibodies were cloned dynamically and mutated to produce the offspring population, meanwhile the infeasible antibodies were repaired towards the feasibility. The simulation experiments on the four kinds of 0/1 knapsack problem with high dimension and comparison with ETGA, RIGA and ISGA demonstrate that the proposed algorithm has better ability in handling constraints and more rapid convergence.

Typical applications

Hierarchical model management framework based on universal relation model representation

XING Ying ZHANG Hongjun ZHANG Rui HE Jian

2013, 33(03):  849-853.  DOI: 10.3724/SP.J.1087.2013.00849

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The exiting model representation cannot meet the requirements of multistage modeling, so model share, reuse and management can hardly achieve in multistage modeling process. Therefore, a hierarchical model management framework based on universal relation model presentation was presented. Firstly, the requirements of model representation in model management and the limitations of exiting model representation were analyzed, then a model representation based on universal relation was investigated to set the mapping relation between layers of conceptual model and mathematical model, and the integrative model representation and the hierarchical model management framework including conceptual model, mathematical model and physical model were set up. At last, the logic of modelbase in management framework was designed and the physical model generation based on universal relation was investigated. The model of different modeling process could be managed uniformly based on an integrative model representation.

Graded address model based on finite state machine and Trie number

ZHANG Qian GUO Sicong

2013, 33(03):  854-857.  DOI: 10.3724/SP.J.1087.2013.00854

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Concerning the address correctness check of parity, address irregular naming and address jumping in the geographic coding system, this paper established a conversion model of hierarchical address by the theory of finite state machine. It also created every address conversion functions in the finite state machine through the Trie tree. Then, it gave the initialization and training process of the conversion function. Through the verification of the model, the address model established in this paper can initially solve these above problems.

Research on hybrid control system of quadrotor UAV

XIA Guoqing LIAO Yuefeng WANG Lu

2013, 33(03):  858-861.  DOI: 10.3724/SP.J.1087.2013.00858

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A hybrid control method based on state feedback and adaptive neural network was proposed, which considered the taking off and landing control problem under unknown mass of the Unmanned Aerial Vehicle (UAV). A state feedback controller was designed to realize the horizontal position and heading control. The accurate control of height was archived considering the vehicle's unknown load through the Radial Basis Function (RBF) neural network. The simulation analysis and experiments illustrate that the proposed control method can effectively realize the accurate control of height, and can be able to online estimate aircraft quality parameters.

Dual priority dynamic scheduling algorithm based on multi-FPGA

DU Shuangzhi WANG Yong TAO Xiaoling

2013, 33(03):  862-865.  DOI: 10.3724/SP.J.1087.2013.00862

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When single Field-Programmable Gate Array (FPGA) deals with the huge amounts of data in high-speed network, low efficiency problem occurs. According to dual priority schedule algorithm for multi-processor and high-speed data acquisition and processing model based on multi-FPGA, a dual priority dynamic scheduling algorithm was proposed based on multi-FPGA. For strong real-time periodic tasks set in low priority queue, the Earliest Deadline Critical Laxity (EDCL) scheduling algorithm was given to determine the priority of task according to the degree of relaxation of the tasks. If the task was not finished when the promotion time was up, it would be promoted to high priority queue. For soft real-time periodic tasks, an algorithm was put forward to assign the tasks to middle priority queue and schedule them by delaying the deadline of tasks to dynamic blur threshold. The experimental results show that the proposed algorithms can well schedule strong real-time periodic tasks and guarantee the priority execution of important tasks, and it can also reduce miss rate of soft real-time periodic tasks caused by preemption.

Real-time wavelet denoising for pulsed eddy current signal based on heterogeneous dual-core

QIU Xuanbing WEI Jilin CUI Xiaochao XIA Chunhua

2013, 33(03):  866-870.  DOI: 10.3724/SP.J.1087.2013.00866

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In order to denoise the Pulsed Eddy Current (PEC) signal from industrial field, a real-time hardware and software system based on heterogeneous dual-core OMAP3530 was designed. First, how to select a wavelet basis was analyzed in the real-time process. The Matlab denoising model based on DB4 wavelet threshold method including Penalty method, B-M method and default method was established, and the Root of Mean Square Error (RMSE) and Signal-to-Noise Ratio (SNR) of the denoising model were given. With reference to the OMAP3530 hardware platform, the system software design of data sharing based on DSPLINK of heterogeneous dual-core was discussed. A real-time filtering algorithm based on fixing length step window was promoted to denoise the PEC signal. The simulation and experimental results indicate that the real-time denoising system has the features of high SNR, strong real-time and high throughput rate to satisfy the requirements of auto-testing on the casting production line.

Spatial query method for Kriging interpolation result

DU Jiusheng CHEN Yijin HOU Zheng

2013, 33(03):  871-873.  DOI: 10.3724/SP.J.1087.2013.00871

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The Kriging interpolation method and its improved models have been widely used, but the interpolation result is raster format and goes against the overlay analysis with vector data. Considering the characteristics of Minimum Enclosing Rectangle (MER) and Voronoi diagram, data structure and spatial query method fit for Kriging interpolation result were proposed. When querying the eigenvalue of a point, by traversing the MERs of various regions, polygons that the point may be in were selected at first. Then the exact polygon was determined by judging the spatial relationship between the point and each polygon. Finally, the eigenvalue of this point was obtained, because it was an attribute of the exact polygon. This query method realized the spatial query of Kriging interpolation. Its validity has been verified by the result of practical operation in an open-pit. The experimental results indicate the query time of this method is controlled in milliseconds, so it is able to meet the requirements of vehicle terminal program in open-pit and other similar applications.

Reconfiguration and optimization of flight control system based on multi-model adaptive method

SHI Zhibo DONG Huifen LI Liyi

2013, 33(03):  874-877.  DOI: 10.3724/SP.J.1087.2013.00874

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For the reconstruction problem of the flight control law when aircraft actuator was damaged or in failure cases, a new reconfiguration scheme of flight control system was proposed based on the linear quadratic optimal control theory and multi-model adaptive method. Based on fault diagnosis and detection technology, the reference model was obtained by the Linear Quadratic Regulator (LQR). Lyapunov stability theory was applied to ensure the strictly positive real parts and global asymptotic stability of the closed-loop control system. According to the vehicle dynamics control law for fault identification and model switching, the reconfiguration and optimization of vehicle control law based on the multi-model adaption was designed. Against the typical fault conditions, the reconfiguration simulation of the flight control system was made to verify the method, and the corresponding verification results were given, which can ensure that the aircraft effective operation.

Discrete sliding-mode guidance laws design based on variable rate reaching law

SHU Yanjun TANG Shuo

2013, 33(03):  878-881.  DOI: 10.3724/SP.J.1087.2013.00878

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A discrete sliding-mode guidance laws based on a new discrete variable rate reaching law was proposed for the discrete form of the missile-target relative motion equation in plane. By adopting this reaching law, steady state oscillation and system chattering were eliminated significantly, and system state approached to zero diminishingly. Maneuvering acceleration of target was considered as unknown external disturbance, and disturbance observer was adopted to estimate and compensate for the uncertainties, which required just knowing the possible variation range of target acceleration between two adjacent sampling instants rather than a prior knowledge of the target acceleration bounds or matched conditions. The simulation results show this method has strong robustness, without steady state oscillation and system chattering.

Application of formal language in automatic marking system of webpage making operation questions

LI Juan

2013, 33(03):  882-885.  DOI: 10.3724/SP.J.1087.2013.00882

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Concerning to the low efficiency and less availability for re-use in automation marking method applied in webpage making operational questions, this paper built up a marking model based on formal language. It analyzed and solved two key issues.Marking information was designed by descriptive language and formal syntax analyses and matching were carried out. Furthermore, some case study illustrates that this particular method improves assessment efficiency and availability for code re-use.

C/S structured questions survey system based on JSP and Android

CHEN Wangting LIN Manzu CHEN Jian ZHANG Yue FU Qijia ZHU Leqing

2013, 33(03):  886-889.  DOI: 10.3724/SP.J.1087.2013.00886

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In order to facilitate the execution of the questionnaire survey, and to improve the efficiency of the statistical data collection, this paper proposed a method to realize a questionnaire survey system based on the Android platform running on mobile phone. The survey system was C/S structured. The server included a questions design module based on Java Server Page (JSP), a result statistical module, the database and the C#-based Web service that gave interfaces to access database. The client was implemented on Android platform, which acquired information of the questions from the database, and displayed questions and their options on the screen for users to answer. When the user completed the answer to the questions, the client would write the answers back to the database. This system was first tested on Android emulator, and then on the mobile phone. The testing results indicate that questions survey function has been efficiently realized in the system. Moreover, since the client can run on a mobile device, the survey process can be carried out freely anywhere, anytime, which means that the survey process would not only be convenient and efficient, but also broaden the target clients of the survey system. The proposed system could be adopted by enterprises or organizations to carry out market or social investigations.

Noise estimation and reduction for chaotic time series by wavelet variance decomposition

HUANG Tengfei LI Bangyi XIONG Jixia

2013, 33(03):  890-895.  DOI: 10.3724/SP.J.1087.2013.00890

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In wavelet noise processing, signal decomposition catches more attention while noise itself is ignored. To solve this problem, by using the function of wavelet variance decomposition to analyze white noise, a new method of noise estimation and reduction by thresholding was proposed for chaotic time series. The noise level was estimated with wavelet variances at first and second scale, while the soft threshold was chosen by calculating wavelet variance of noise at every scale. The method was tested in Lorenz and Chen's system. The result shows that the proposed method is better than other wavelet noise estimation and reduction methods. At last, it is proved to be effective in de-noising Shanghai Stock Exchange (SSE) index and Shanghai Futures Exchange (SHFE) rubber futures time series.

Finite element simulation of implant surgery for vocal cord paralysis

CHEN Weitao CHEN Dongfan HAN Xingqian ZHOU Chen GAO Xiang

2013, 33(03):  896-900.  DOI: 10.3724/SP.J.1087.2013.00896

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As surgeons do not have effective prediction on the the implant surgery for vocal cord paralysis, resulting in high rate of failure, the finite element method was used for preoperative simulation. Through Computed Tomography (CT) data of larynx, the 3D geometric model of vocal cords and glottis trachea was extracted by Mimics, and then imported into ANSYS-Fluent to simulate the vocal vibration mode and airflow dynamic coupling characteristics before and after implanted surgery. The experimental data and clinical statistics data were compared to prove the feasibility of the finite element analysis techniques for implant surgery simulation of vocal cord paralysis. The experimental result can provide support for the design of surgery program.