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• 2012, No. 4　Published:26 April 2012 Last issue    Next issue
  Columns in this issue: 论文

• 论文

  Performance Analysis of the Intersatellite Links Based on 3Layer Satellite Networks

  HUANG Feijiang1,2,4,YANG Jun1,LU Xiaochun3,4,SHAN Qingxiao1,ZHOU Yongbin1,CH

  2012, 34(4): 1-6. doi:

  Abstract ( 441 )   PDF (530KB) ( 516 )   　　

  Performance analysis of intersatellite links is the basis for establishing intersatellite communications. A 3layer satellite network containing GEO, IGSO, and MEO satellites is used as an example to simulate the variation range of distance interlayer satellites of the 3layer satellite network and to analyze the performance of GEOIGSO, GEOMEO, and IGSOMEO links in Kaband and laser links under the preset intersatellite transmission system, link parameters, transmission loss,etc. Results show that 0.5m antennas only need 5W transmitting power to provide an intersatellite data transmission rate higher than 2Mb/s in the Kaband and the laser links data transfer rate can achieve to more than 2Gb/s with 0.5W launching power and the 0.25m antenna diameter. The laser links greatly improve the communication ability compared with the microwave frequency band. This serves as a reference for the selection of the transmitting power, antenna diameter, and intersatellite information transmission rate of satellites during the establishment of intersatellite links for 3layer satellite networks in the future.

  An Interference Mitigation Protocol Based on MultiPath Routing

  KAN Baoqiang，FAN Jianhua，LU Ziyi,CHENG Jie,WU Qiang

  2012, 34(4): 7-11. doi:

  Abstract ( 350 )   PDF (647KB) ( 269 )   　　

  As the distributed and dynamic network architecture, the broadcast nature of wireless medium and stringent resource constraints of wireless devices makes MHWN （multihop wireless network）extremely attractive and vulnerable to malicious attacks. So how to ensure continuous network service becomes a critical problem especially in jammed situations. In this paper，interference avoidance mechanisms are  well concerned. Then a proactive multipath routing mechanism based on interference dynamic measuring is proposed to improve the MHWN performance under jamming. The proposed mechanisms need extra support in the form of routing interference entries to build higher robust antijamming paths in MHWN, while keeping the less reroute request times. Our evaluations based on NS2 show that the proposed mechanisms can provide robust antijamming paths for MHWN.

  An Opportunistic Cooperative Multicast Scheduling Strategy for Optimizing Broadcasting Latency

  CHEN Yande1,SONG Liubin1,2,LI Gang1,ZHANG Lian1,TAN Li1

  2012, 34(4): 12-16. doi:

  Abstract ( 334 )   PDF (465KB) ( 317 )   　　

  The most serious problem of the wireless multicast system is the all users’ QoS (Quality of Service) demands can not be satisfied simultaneously for the variety and unequality of users’ channels. In wireless cellular communication systems, packets should inevitably be transmitted multiple times to achieve reliable multicast，which increases the multicast latency. In this paper, we first analyze the latency of cooperative multicast scheduling (CMS) and derive the minimal latency at the assumption that we know the total channel state information. In addition, an opportunistic cooperative multicast scheduling (OCMS) strategy is proposed to optimize the multicast latency on the condition that only part of the channel state information is achieved by some feedback signals. The simulation results show that the proposed strategy almost reaches the optimal latency of CMS and outperforms other schemes markedly on the performance of transmission latency.

  A Novel Survey on the Image Watermarking Algorithms

  ZHANG Xiaoqiang1，WANG Mengmeng2，ZHU Guiliang2

  2012, 34(4): 17-22. doi:

  Abstract ( 369 )   PDF (488KB) ( 541 )   　　

  With the rapid development of computer and information technology, as the key techniques of digital image copyright protection and integrity authentication, digital watermarking has been widely studied and applied. An overview of the recent developments in image watermarking is introduced, and the main techniques of image watermarking are illustrated. We discuss the main schemes, characteristics and new development of the robust watermarking, fragile watermarking, and semifragile watermarking algorithms. Finally, the development trend of the image watermarking technology is discussed in this paper.

  Device Characteristics of LDMOS with the GaussShape Surface in the Drift Region

  LUO Xiangdong,ZHAI Xianzhen,DAI Shanshan,YU Chenhui，LIU Peisheng

  2012, 34(4): 23-27. doi:

  Abstract ( 354 )   PDF (1487KB) ( 294 )   　　

  A LDMOS structure with the Gaussshape surface in the drift region is proposed here. Pwell, channel, source region, polysilicon gate are set on one side of the Gauss center, and the drain region is put on the other side of the Gauss center. This LDMOS structure has high breakdown voltage of the LDMOS with a gradient surface in the drift region, but also has high onstate breakdown voltage and safe operating area. By changing the height factor of the Gauss shape of the drift region, the drift region with the Gaussshape surface is studied. The results indicate that high temperature drivein of pwell changes the net doping of the drift region with different Gaussshape surfaces. The device breakdown voltage and the surface electric field profile of the LDMOS structures with different Gaussshape surfaces are investigated by changing the height factor of the Gauss shape. There has an optimized onstate breakdown voltage and a smooth surface electric profile when the height factor is around 0.5. Meanwhile, when the height factor increases from 0.5 to 1.0, the onstate breakdown voltage is saturated.

  Thermal Simulation and Design of a MultiChip Package

  WANG Jinlan1，TONG Liangyu1,2，LIU Peisheng1,2,3，MIAO Xiaoyong2

  2012, 34(4): 28-31. doi:

  Abstract ( 440 )   PDF (854KB) ( 412 )   　　

  Thermal design of the IC package is to improve the thermal dissipation ability of the package. Multi chippackage (MCP) is designed to increase the density of integrated electronics and improve the processing power. Due to the multiheat sources in a package, heat management becomes more critical for MCPs. This paper presents the finite elements simulation of FBGA MCP product. The effect of chip thickness to the thermal resistance of the package is presented. Through a comparison of the thermal performances, the chip placement is optimized. The simulation results show that chip thickness does not have a profound effect to the thermal resistance of MCPs, and the smallest thermal resistance is obtained when the two chips are symmetrically arranged in the center of the substrate.

  LIDAR Target Recognition Based on Point CloudsModel Matching

  TAN Zhiguo1,LU Min1,HU Yanping2,GUO Yulan1,ZHUANG Zhaowen1

  2012, 34(4): 32-36. doi:

  Abstract ( 390 )   PDF (640KB) ( 418 )   　　

  For the lidar automatic target recognition purpose, a method based on point cloudsmodel matching is proposed in this paper. The point clouds are  projected to 3views and binary images are created after binarization. The Sobel operator and Hough transform are applied to the binary images to extract the silhouette boundary and line parameters, then the bounding rectangles are  extracted with the restriction of projected point clouds’ silhouette information, thus the target’s orientation and geometric feature are obtained. Taking the minimum of the mean Euclidean distance between point clouds and facets of the CAD model as the optimization target, utilizing the unit quaternion method for rigid transform calculation, the matching between point clouds and the CAD model is realized by using iteration, and the recognition process is finished by taking the normalized mean Euclidean distance as similarity metric. Point clouds of five kinds of ground armored vehicles in different lidar viewing angles are  used to fulfill the recognition experiment. The statistical results show that the target’s class recognition rate is 100% and the type recognition rate is above 91%. So this method performs well on recognition and has better application prospect.

  A Parallelized MultiScale Retinex Video Enhancement Algorithm Based on CUDA

  YANG Jun1,CAO Jing2,ZHANG Zhengxiao3,WANG Zhengning4

  2012, 34(4): 37-42. doi:

  Abstract ( 392 )   PDF (1179KB) ( 311 )   　　

  The MSR (MultiScale Retinex) image and video enhancement algorithm can produce the best performance in most cases and is very popular in the field of video enhancement. However, MSR can not be applied and extended widely in realtime processing because the computation load is very huge especially for high definition and multichannel videos. Thus the study on parallelized highspeed algorithms is tremendously significant. A parallel approach based on general GPU(Graphic Processing Unit) via CUDA(Compute Unified Device Architecture) is proposed in this paper in order to accelerate the speed of multiscale retinex video enhancement. By implementing the computation complexity modules such as multiscale Gaussian filtering, logarithmic domain differentiating and dynamic range compressing on GPU, and reducing the parameters updating frequency by using the similarity between consecutive frames, the computation complexity is saved a lot. The experimental results show that the proposed method can improve the computation speed significantly.

  A Novel Approach for Moving Object Segmentation Used in Dynamic Scenes

  MA Zhiqiang，ZHANG Xiaoyan，ZHU Zijian，ZHANG Rui

  2012, 34(4): 43-46. doi:

  Abstract ( 300 )   PDF (908KB) ( 381 )   　　

  Video moving object segmentation is a basic problem of computer vision and video processing. In the video sequences of a dynamic scene which has global (camera) motion, accurate moving object segmentation is still a key and hot research topic. A novel video moving object segmentation algorithm based on global motion compensation and nonparametric kernel density estimation is proposed in this paper. Firstly, an efficient and accurate global motion compensation method is used to remove the motion of the background. Then the nonparametric kernel density estimation is applied to establish foreground/background probability models. Finally, the moving object can be obtained by comparing the foreground/background probability and morphological postprocessing. The experimental results demonstrate that the proposed algorithm has good results and reduces the complexity of moving object segmentation in dynamic scenes.

  A Parallel Image Matching Algorithm Based on YHFTQDSP

  LIU Zhong,XING Binchao,HU Xiao

  2012, 34(4): 47-51. doi:

  Abstract ( 408 )   PDF (1164KB) ( 325 )   　　

  A parallel image matching algorithm based on YHFTQDSP is proposed, which adopts a datalevel parallel method to implement parallel keypoints extraction and matching, and fully develops multilevel parallelism of multicore processors. The parallel algorithms for SIFT, SURF and PCASIFT are implemented and evaluated, and the experimental results show that the parallel image matching algorithms have good adaptability for various distortion images and the image matching ability is close to the sequential algorithm with the average speedup of 3.2.

  Research on the Metamorphic Testing for Integer Bugs Detection

  YAO Yi1,2，HUANG Song2，JI Mengyu2

  2012, 34(4): 52-56. doi:

  Abstract ( 327 )   PDF (474KB) ( 280 )   　　

  The integer bugs play a vital role in the functionality and security of software. For the Oracle problem, integer bugs are always ignored unless program throws an exception obviously. In this paper, a metamorphic relation is provided to detect invisible integer bugs without oracle. It is shown in our case study that this method can detect some invisible errors which are difficult to be found by conventional approaches and improve the efficiency of integer bugs detection.

  Local Features for Occlusion in Object Tracking

  MENG Bo1,QU Zhaoyang1，MAO Wenbei2,GUO Xiaoli1

  2012, 34(4): 57-60. doi:

  Abstract ( 349 )   PDF (582KB) ( 377 )   　　

  To solve the occlusion problem of object tracking in videos, a local shape feature is proposed to estimate the occlusion state. In this correlate matching algorithm, the methods combine the local features which are not occluded and the motion predictions to calculate the object portion. In this way, the influence brought by the occluded is avoided. The experimental results show that the algorithm is robust to solving the occlusion problem, and the occluded state judged by the proposed local shape feature is correct.

  A New Rate Control Algorithm for the H.264 Frame Layer

  SU Linghua1,2,GUO Ying1,ZHANG Shuyin1

  2012, 34(4): 61-65. doi:

  Abstract ( 363 )   PDF (802KB) ( 300 )   　　

  In this paper, we propose a new rate control algorithm for the H.264 frame layer. A novel RQ (RateQuantization) model for Iframes is established based on rate, spatial complexity and buffer status. The target bits of an I frame is decided by the relation between the number of bits generated for the I frame and P frames of the previous GOP, and the QPi(Quantization Parameter for I frame) is determined adaptively. The target bits of a P frame is modified according to the HOD (Histogram of Difference) and its relative position. The experimental results show that the proposed algorithm can increase the average PSNR (Peak Signal-to-Noise Ratio) of the reconstructed video, and depress the PSNR fluctuations. At the same time, some skipped frames are avoided.

  Research on Wrong Match Pairs Elimination Based on Similar Triangles in the SIFT Algorithm

  ZHANG Dongxing,ZHU Mingbo,ZOU Jianwu,LI Xiangping

  2012, 34(4): 66-70. doi:

  Abstract ( 350 )   PDF (736KB) ( 343 )   　　

  Image matching is a key technology of image processing applied to many fields. The image matching based on invariant features is the hot spot in image match research recently. SIFT is one of the most effective scale, rotation and illumination invariant features. However there are a lot of wrong match pairs produced by the original SIFT algorithm. Two specific types of wrong matches are analyzed and the corresponding eliminating methods are given. Aiming at general wrong match elimination, a method based on similar triangles is proposed. Experiments are carried out and the results confirm that: the proposed method is faster than the commonlyused two algorithms and it can eliminate wrong matches and preserve correct matches as well.

  A Matching Algorithm of High Resolution Images Based on Hardware Accelerators and Its Application

  HUANG Junjie,HU Xiao

  2012, 34(4): 71-76. doi:

  Abstract ( 324 )   PDF (529KB) ( 294 )   　　

  Restricted to hardware resources, the SAD accelerator can only realize the matching of small images. This paper proposes an algorithm of matching high resolution images. This algorithm divides high resolution images to base granularity computation blocks. This algorithm has good matching precision and efficiency, and it is applied into the twograde pyramid algorithms, and gets a good result.

  A SingleSource Shortest Path Algorithm Based on the Bucket Structure

  WEI Wenhong1,LI Qingxia2,CAI Zhaoquan3

  2012, 34(4): 77-81. doi:

  Abstract ( 379 )   PDF (461KB) ( 357 )   　　

  The singlesource shortest path problem as to the main optimal routing problem is the basis of the most optimal problems in many social application areas. This paper discusses the different singlesource shortest path serial algorithms in term of the implementation technique, combining the ideas of the Dijkstra algorithm based on label setting and the BFM algorithm based on label correcting, a new kind of singlesource shortest path algorithm based on the bucket structure is proposed. The experiments show that the proposed algorithm has good time complexity and parallelism property compared with the two former algorithms.

  An Adaptive Network Based Fuzzy Inference System Based on UKF

  XU Xiaolai1,2,ZHU Huayong1,HE Zhongwu2,WANG Wei2,NIU Yifeng1

  2012, 34(4): 82-87. doi:

  Abstract ( 342 )   PDF (1166KB) ( 335 )   　　

  Much of the current research interest in neurofuzzy hybrid systems is focused on how to generate an optimal number of fuzzy rules in a neurofuzzy system and investigate the automated methods of adding and pruning fuzzy rules. To deal with this problem, an adaptive network based fuzzy inference system (ANFIS) based on UKF is presented. Firstly, fuzzy rules and their parameters of ANFISRR are obtained by subtractive clustering. Secondly, the parameters are learned by linear least square and the back propagation algorithm. Thirdly, the nonlinear dynamical system expression of fuzzy networks is analyzed, and LLS and UKF are used to learn linear and nonlinear parameters respectively. Then, a method of error descending rate is used as the fuzzy rule pruning strategy, so that the rule which plays an unimportant role in the system is deleted. Finally, by typical experiments of function approximation and system identification indicate that fuzzy networks obtained by the proposed algorithm has a more tightened structure and better generalization than other algorithms.

  The Opportunities and Challenges of Data Mining in Gas Turbine Engine Prognostics and Health Management

  WEI Xunkai1,2，ZHU Jihong2，CHEN Liangfeng1，FENG Yue1，YANG Li1

  2012, 34(4): 88-93. doi:

  Abstract ( 394 )   PDF (479KB) ( 569 )   　　

  Prognostics and health management is an enabled supporting key technology for ensuring flight safety and twolevel conditionbased maintenance. Data mining is the core implementation technology for engine health status assessment, diagnostics and remaining useful life prediction. First, the military needs and the significance of the PHM technology accompanying with the role of data mining in PHM are briefly reviewed. Then, the key data mining problems and challenges in gas turbine PHM are detailed. Finally, it is argued that the maturing of PHM should be under the collaboration of the computer subject and the aerospace subject.

  Entropy Theory and Information Granularity in Information Systems

  TENG Shuhua，LU Min，ZHANG Jun，TAN Zhiguo，ZHUANG Zhaowen

  2012, 34(4): 94-101. doi:

  Abstract ( 357 )   PDF (497KB) ( 317 )   　　

  One of the most important issues in artificial intelligence is uncertainty. Many uncertainty measuring methods have been put forward and widely used in information systems, such as entropy theory and information granularity, which are two main approaches to study the uncertainty of an information system. In this paper, the physical meaning of entropy and the entropy increase principle in information systems are presented firstly, then the axiom definitions of entropy and information granularity are provided and two new uncertainty measureing functions αentropy and αgranularity using this method are developed. Analysis shows that some of the existing definitions of entropy and information granularity become the special forms of axiom definitions. The results unify, standardize and develop the theory of uncertainty measureing in complete and incomplete information systems.

  Safety Analysis of a Kind of Embedded Software Working in a Signal Indicating System

  WANG Hongpo，ZHOU Hongjian

  2012, 34(4): 102-107. doi:

  Abstract ( 373 )   PDF (527KB) ( 274 )   　　

  The safety problem of a kind of embedded software is discussed in this paper. The safety model of this kind of software is established based on the FSM and Markov chain theories. The safety degree of the system is defined according to gray entropy. It offers a way to quantify the safety of the system. It also gives a way to get the values of the equations. Finally, numerical simulation is applied to study the influence of the parameter of the equations on system safety, and shows the way to enhance the safety of the system.