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26 June 2006, Volume 17 Issue 2
Review of space information technology
Thong Shan, Hou Pingmei
2006, 17(2):  237-244.  doi:10.1016/S1004-4132(06)60041-8
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The features of information technology (IT) are discussed first On this basis, the features of space information technology (SIT) are presented and SIT is elaborated in five categories. The popularization of SIT is an informatization process and will promote the industrialization of national economy and the modernization of industry such as agriculture.The necessity of the synthetical application of SIT is studied emphatically, and the development trend of SIT is discussed.

UKF-based multi-sensor passive tracking with active assistance
Li Anping, Jing Zhongliang & Hu Shiqiang
2006, 17(2):  245-250.  doi:10.1016/S1004-4132(06)60042-X
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A new synergy tracking method of infrared and radar is presented. To improve tracking accuracy, the unscented Kaiman filter (UKF) , which has better nonlinear approximation ability, is adopted. In addition, to reduce the possibility of radar being locked-on by adverse electronic support measure (ESM) , radar is under the intermittent-working state. After radar is turned off, the possible target position is estimated by a set of time polynomials, which is constructed based on the sufficient observations done before radar is turned off, the estimated values from time polynomials are compared with the current observation values from infrared to determine the time when radar is turned on. Simulation results show the method has a good tracking accuracy and effectively reduces the possibility of radar being locked-on by adverse ESM.
Contour representation based on wedgelet
Liu Zeyi, Sun Ziqiang, Xu Ling &· Peng Xiang,
2006, 17(2):  251-257.  doi:10.1016/S1004-4132(06)60043-1
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Aiming at the shortcomings of the existing wedgelet compression arithmetics, a novel contour-representing algorithm based on wedgelets is presented in this paper. Firstly the input image is binarized and the most optimized wedgelets are found by means of quadtree framework. Then the contours are reconstructed by applying the wedgelets, the data volume is compressed, and the shortcomings of the contour representation based on normal wavelet are ameliorated, the better effect for the visualization is obtained, too.
Efficient spread space-time block coding scheme in multiple antenna systems *
Qiu Ling & Zheng Xiayu
2006, 17(2):  258-262.  doi:10.1016/S1004-4132(06)60044-3
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Space-time coding is an important technique that can improve transmission performance at fading environments in mobile communication systems. In this paper, we propose a novel diversity scheme using spread spacetime block coding (SSTBC) in multiple antenna systems. At the transmitter, the primitive data are serial to parallel converted to multiple data streams, and each stream is rotated in constellation. Then Walsh codes are used to spread each symbol to all antenna space in a space-time block. The signals received from all receiver antennas are combined with the maximum ratio combining (MRC) , equalized with linear equalizer to eliminate the inter-code interference and finally demodulated to recover to transmit data by using the one-symbol maximum likelihood detector. The proposed scheme does not sacrifice the spectrum efficiency meanwhile maintains the transceiver with low complexity. Owing to the transmission symbols of different transmit antennas passing through all the spatial subchannels between transceiver antenna pairs, the system obtains the partial additional space diversity gain of all spatial paths. It is also shown that the diversity gain is better than the previous space-time block coding (STBC) schemes with full transmission rate.
Efficient coding schemes with power allocation using space-time-frequency spreading*
Jiang Haining , Luo Han-wen , Tian J if eng, Song Wentao & Liu Xingzhao
2006, 17(2):  263-267.  doi:10.1016/S1004-4132(06)60045-5
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An efficient space-time-frequency (STF) coding strategy for multi-input multi-output orthogonal frequency division multiplexing (MEMO-OFDM) systems is presented for high bit rate data transmission over frequency selective fading channels. The proposed scheme is a new approach to space-time-frequency coded OFDM (COFDM) that combines OFDM with space-time coding, linear precoding and adaptive power allocation to provide higher quality of transmission in terms of the bit error rate performance and power efficiency. In addition to exploiting the maximum diversity gain in frequency, time and space, the proposed scheme enjoys high coding advantages and low-complexity decoding. The significant performance improvement of our design is confirmed by corroborating numerical simulations.
New algorithm for infrared small target image enhancement based on wavelet transform and human visual properties
Wang Xuewei, Liu Songtao & Zhou Xiaodong
2006, 17(2):  268-273.  doi:10.1016/S1004-4132(06)60046-7
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The key to the wavelet based denoising techniques is how to manipulate the wavelet coefficients. By referring to the idea of Inclusive-OR in the design of circuits, this paper proposes a new algorithm called wavelet domain Inclusive-OR denoising algorithm (WDIDA), which distinguishes the wavelet coefficients belonging to image or noise by considering their phases and modulus maxima simultaneously. Using this new algorithm, the denoising effects are improved and the computation time is reduced. Furthermore, in order to enhance the edges of the image but not magnify noise, a contrast nonlinear enhancing algorithm is presented according to human visual properties. Compared with traditional enhancing algorithms, the algorithm that we proposed has a better noise reducing performance, preserving edges and improving the visual quality of images.
UWB radar target recognition based on time-domain bispectrum
Liu Donghong, Zhang Yongshun, Chen Zhijie' & Cheng Junbin
2006, 17(2):  274-278.  doi:10.1016/S1004-4132(06)60047-9
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Complex targets are irradiated by UWB radar, not only the mirror scattering echoes but also the multiscattering interacting echoes are included in target echoes. These two echoes can not be distinguished by classical frequency spectrum and power spectrum. Time-domain bispectrum features of UWB radar signals that mingled with noise are analyzed, then processing this kind of signal using the method of time-domain bispectrum is experimented. At last, some UWB radar returns with different signal noise ratio are simulated using the method of time-domain bispectrum. Theoretical analysis and the results of simulation show that the method of extraction partial features of UWB radar targets based on time-domain bispectrum is good, and target classification and recognition can be implemented using those features.
Target recognition based on modified combination rule *
Oxen Tianlu & Que Peiwen
2006, 17(2):  279-283.  doi:10.1016/S1004-4132(06)60048-0
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Evidence theory is widely used in the field of target recognitioa The invalidation problem of this theory when dealing with highly conflict evidences is a research hotspot. Several alternatives of the combination rule are analyzed and compared. A new combination approach is proposed. Calculate the reliabilities of evidence sources using existing evidences. Construct reliabilities judge matrixes and get the weights of each evidence source. Weight average all inputted evidences. Combine processed evidences with D-S combination rule repeatedly to identify a target. The application in multi-sensor target recognition as well as the comparison with typical alternatives all validated that this approach can dispose highly conflict evidences efficiently and get reasonable recognition results rapidly.
View synthesis based on the serial images from camera lengthways motion
Thang Jing, Wang Changshun, Liao Wuling, Ou Zongying & Hua Shungang
2006, 17(2):  284-289.  doi:10.1016/S1004-4132(06)60049-2
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For the pre-acquired serial images from camera lengthways motion, a view synthesis algorithm based on epipolar geometry constraint is proposed in this paper. It uses the whole matching and maintaining order characters of the epipolar line, Fourier transform and dynamic programming matching theories, thus truly synthesizing the destination image of current viewpoint. Through the combination of Fourier transform, epipolar geometry constraint and dynamic programming matching, the circumference distortion problem resulting from conventional view synthesis approaches is effectively avoided. The detailed implementation steps of this algorithm are given, and some running instances are presented to illustrate the results.
Piecewise linear recursive convolution FDTD method for magnetized plasmas
Liw Song, Thong Shuangying & Lzw Shaobin
2006, 17(2):  290-295.  doi:10.1016/S1004-4132(06)60050-9
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The piecewise linear recursive convolution (PLRC) finite-different time-domain (FDTD) method greatly improves accuracy over the original recursive convolution (RC) FDTD approach but retains its speed and efficiency advantages. A PLRC-FDTD formulation for magnetized plasma which incorporates both anisotropy and frequency dispersion at the same time is presented, enabled the transient analysis of magnetized plasma media The technique is illustrated by numerical simulations the reflection and transmission coefficients through a magnetized plasma layer. The results show that the PLRC-FDTD method has significantly improved the accuracy over the original RC method.
Investigating path loss characteristics of UWB signals in vacancy indoor environment based on time-domain technique*
Wang Yang & Zhang Naitong
2006, 17(2):  296-302.  doi:10.1016/S1004-4132(06)60051-0
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The path loss analysis model based on 5 rays in vacancy indoor environment is proposed. The relationship between multipath overlapping and the path loss is analyzed mathematically. Time-domain technique is introduced to compute reflection coefficient in a very short time interval. A 5 rays path loss calculation method, which is satisfactory accurate, is developed. 5 typical environments are involved to analyze and generalize the common path loss characteristics in vacancy indoor environment The simulation result shows that the path loss can be characterized as 3 zones with different path loss exponent as distance between transmitter and receiver increasing.
Low complexity reconfigurable architecture for the 5/3 and 9/7 discrete wavelet transform
Xiong Chengyi, Tian Jinwen & Liu Jian
2006, 17(2):  303-308.  doi:10.1016/S1004-4132(06)60052-2
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Efficient reconfigurable VLSI architecture for 1-D 5/3 and 9/7 wavelet transforms adopted in JPEG2000 proposal, based on lifting scheme is proposed. The embedded decimation technique based on fold and time multiplexing, as well as embedded boundary data extension technique, is adopted to optimize the design of the architecture. These reduce significantly the required numbers of the multipliers, adders and registers, as well as the amount of accessing external memory, and lead to decrease efficiently the hardware cost and power consumption of the design. The architecture is designed to generate an output per clock cycle, and the detailed component and the approximation of the input signal are available alternately. Experimental simulation and comparison results are presented, which demonstrate that the proposed architecture has lower hardware complexity, thus it is adapted for embedded applications. The presented architecture is simple, regular and scalable, and well suited for VLSI implementatioa.
A pre-processing blind multiuser detection algorithm based on LSCM using antenna array *
Fu Hong Hang & Feng Guangzeng
2006, 17(2):  309-312.  doi:10.1016/S1004-4132(06)60053-4
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A pre-processing blind multiuser detection algorithms based on the least squares constant modulus (PLSCMA) using antenna array is proposed in this paper. It first uses the signals received from every antenna to correlate with the conjugation of the DoA vector of the expected user, and then applies the pre-processed signals to the LSCMA. We simulate and compare the proposed algorithm with the conventional LSCMA Simulation results show that the proposed algorithm is superior to LSCMA.
Adaptive cancellation of Es layer interference using auxiliary horizontal antennas
Zhao Long & Zhang Ning
2006, 17(2):  313-315.  doi:10.1016/S1004-4132(06)60054-6
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Based on a dual-polarization high-frequency wave radar system, an adaptive system using horizontal antennas for the suppression of the Es layer interference (ELI) is described. The data received from the horizontal antennas were correlated with the data received from the Vertically Polarized Antennas (VPAs) to estimate and cancel the interference adaptively in the VPAs. Suppressing the interference after each coherent integration time interval, about 25 dB signal-to-interference ratio is expected with the experimentally derived data.
New edge detection method for high-resolution SAR images
Chang Yulin, Zhou Zhimin, Chang Wenge & Jin Tian
2006, 17(2):  316-320.  doi:10.1016/S1004-4132(06)60055-8
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A new edge detection method combining the scanning window central edge (SWCE) detector and an improved active contour model is proposed. The method first emploies the SWCE detector based on the difference of area pixel value means to perform an optimal edge detection, and then proposes an improved active contour model with modified energy functions to refine the location of the edges. The initial nodes of the improved active contour model are automatically found from the vectorised results of the SWCE detector. Tests on simulated speckled images and real airborne SAR images show that the combined method can benefit from the advantages of the both techniques and get satisfactory edge detection and localization abilities at the same time.
Blind source separation of ship-radiated noise based on generalized Gaussian model
Kong Wei & Yang Bin
2006, 17(2):  321-325.  doi:10.1016/S1004-4132(06)60056-X
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When the distribution of the sources cannot be estimated accurately, the ICA algorithms failed to separate the mixtures blindly. The generalized Gaussian model (GGM) is presented in ICA algorithm since it can model non-Gaussian statistical structure of different source signals easily. By inferring only one parameter, a wide class of statistical distributions can be characterized. By using maximum likelihood (ML) approach and natural gradient descent, the learning rules of blind source separation (BSS) based on GGM are presented. The experiment of the ship-radiated noise demonstrates that the GGM can model the distributions of the ship-radiated noise and sea noise efficiently, and the learning rules based on GGM gives more successful separation results after comparing it with several conventional methods such as high order cumulants and Gaussian mixture density function.
Research on assessment system of accomplishment
Fu Zhimin & Li Hanling
2006, 17(2):  326-330.  doi:10.1016/S1004-4132(06)60057-1
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Project assessment of accomplishment is a complicated process of system engineering management. This paper is based on the examination of project management achievement A system analysis of accomplishment examination has been made from the implication, content, style, method, aim, principle, procedure, kind to restriction, psychology effect of accomplishment examinatioa The purpose of aforementioned all is for the establishment of whole system and thought in the study, foundation and implement of project accomplishment assessment.
Function S-Rough sets and its applications *
Cut Yuquan & Shi Kaiquan
2006, 17(2):  331-338.  doi:10.1016/S1004-4132(06)60058-3
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Based on S-rough sets(singular rough sets), this paper presents function S-rough sets (function singular rough sets)and its mathematical structures and features. Function S-rough sets has two forms: function one direction S-rough sets (function one direction singular rough sets) and function two direction S-rough sets (function two direction singular rough sets). This paper advances the relationship theorem of function S-rough sets and S-rough sets. Function Srrough sets is the general form of S-rough sets, and S-rough sets is the special case of function Srough sets. In this paper, applications of function S-rough sets in rough law mining-discovery of system are given. Function S-rough sets is a new research direction of rough sets and rough system.
Target distribution in cooperative combat based on Bayesian optimization algorithm*
Shi Zhifu , Zhang An & Wang Anli
2006, 17(2):  339-342.  doi:10.1016/S1004-4132(06)60059-5
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Target distribution in cooperative combat is a difficult and emphases. We build up the optimization model according to the rule of fire distributioa We have researched on the optimization model with BOA. The BOA can estimate the joint probability distribution of the variables with Bayesian network, and the new candidate solutions also can be generated by the joint distribution. The simulation example verified that the method could be used to solve the complex question, the operation was quickly and the solution was best.
Tracking maneuvering target based on neural fuzzy network with incremental neural leaning*
Liu Mei , Quan Taifan & Yao Tianbin
2006, 17(2):  343-349.  doi:10.1016/S1004-4132(06)60060-1
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The scheme for tracking maneuvering target based on neural fuzzy network with incremental neural learning is proposed. When tracked target maneuver occurs, the scheme can detect maneuver immediately and estimate the maneuver value accurately , then the tracking filter can be compensated correctly and duly by the estimated maneuver value. When environment changes, neural fuzzy network with incremental neural learning (INL-SONFIN) can find its optimal structure and parameters automatically to adopt to changed environment. So, it always produce estimated output very close to the true maneuver value that leads to good tracking performance and avoids misstracking. Simulation results show that the performance is superior to the traditional schemes and the scheme can fit changed dynamic environment to track maneuvering target accurately and duly.
Feedforward and feedback optimal control for linear time-varying systems with persistent disturbances
Tang Gongyou, Zhao Yandong & Zhang Baolin
2006, 17(2):  350-354.  doi:10.1016/S1004-4132(06)60061-3
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The optimal control problem for linear time-varying systems affected by external persistent disturbances with known dynamic characteristics but unknown initial conditions is consider and a design procedure of a feedforward and feedback optimal controller is presented The condition of existence and uniqueness of the control law is givea The disturbance observer is proposed to make the feedforward control law realizable physically. Simulation results demonstrate that the feedforward and feedback optimal control law is more effective and robust than the classical state feedback control law with respect to external disturbances.
Feature point matching of curved surface and robust uncertainty *
Tian Jinsi & Su Jianbo
2006, 17(2):  355-361.  doi:10.1016/S1004-4132(06)60062-5
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Stereo matching is an important research area in stereovision and stereo matching of curved surface is especially crucial. A novel correspondence algorithm is presented and its matching uncertainty is computed robustly for feature points of curved surface. The corners are matched by using homography constraint besides epipolar constraint to solve the occlusion problem. The uncertainty sources are analyzed. A cost function is established and acts as an optimal rule to compute the matching uncertainty. An adaptive scheme Gauss weights are put forward to make the matching results robust to noises. It makes the practical application of corner matching possible. From the experimental results of an image pair of curved surface it is shown that computing uncertainty robustly can restrain the affection caused by noises to the matching precision.
Analysis of one dimensional and two dimensional fuzzy controllers*
Ban Xiaojun, Gao Xiaozhi, Huang Xianlin & Ww Tianbao
2006, 17(2):  362-373.  doi:10.1016/S1004-4132(06)60063-7
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The analytical structures and the corresponding mathematical properties of the one dimensional and two dimensional fuzzy controllers are first investigated in detail. The nature of these two kinds of fuzzy controllers is next probed from the perspective of control engineering. For the one dimensional fuzzy controller, it is concluded that this controller is a combination of a saturation element and a nonlinear proportional controller, and the system that employs the one dimensional fuzzy controller is the combination of an open-loop control system and a closedloop control system. For the latter case, it is concluded that it is a hybrid controller, which comprises the saturation part, zero-output part, nonlinear derivative part, nonlinear proportional part, as well as nonlinear proportional-derivative part, and the two dimensional fuzzy controller-based control system is a loop-varying system with varying number of control loops.
Decentralized direct adaptive neural network control for a class of interconnected systems *
Zhang Tianping & Met Jiandong
2006, 17(2):  374-380.  doi:10.1016/S1004-4132(06)60064-9
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The problem of direct adaptive neural network control for a class of large-scale systems with unknown function control gains and the high-order interconnections is studied in this paper. Based on the principle of sliding mode control and the approximation capability of multilayer neural networks, a design scheme of decentralized direct adaptive sliding mode controller is proposed. The plant dynamic uncertainty and modeling errors are adaptively compensated by adjusted the weights and sliding mode gains on-line for each subsystem using only local informatioa According to the Lyapunov method, the closed-loop adaptive control system is proven to be globally stable, with tracking errors converging to a neighborhood of zero. Simulation results demonstrate the effectiveness of the proposed approach.
LMI approach to reliable ffoo control of linear systems
Yao Bo & Wang Fuzhong
2006, 17(2):  381-386.  doi:10.1016/S1004-4132(06)60065-0
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The reliable design problem for linear systems is concerned with. A more practical model of actuator faults than outage is considered. An LMI approach of designing reliable controller is presented for the case of actuator faults that can be modeled by a scaling factor. The resulting control systems are reliable in that they provide guaranteed asymptotic stability and Hoo performance when some control component (actuator) faults occur. A numerical example is also given to illustrate the design procedure and their effectiveness. Furthermore, the optimal standard controller and the optimal reliable controller are compared to show the necessity of reliable control. 
Synchronization of two 3-scroll hyperchaotic attractors using wavelet transform
Li Jian, Zhou Jiliu, Wang Ybng & Zhi Yong
2006, 17(2):  387-389.  doi:10.1016/S1004-4132(06)60066-2
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The synchronization of two 3-scroll hyperchaotic attractors is realized based on wavelet transform and single variables } feedback. In the transmitter, one signal is decomposed by wavelet transform and the detailed information is removed, then the component with low frequency is reconstructed and sent into the channel In the receiver, the received signal is used as the feedback signal to realize the synchronization of two chaotic systems. Using this synchronous method, the transmitting signal is transported in compressible way, the system resource is saved, furthermore, because the transported signal is not a whole chaotic signal, the performance of security of the system is improved. 
Non-gyroscope DR and adaptive information fusion algorithm used in GPS/DR device
Li Qingli, Xue Yongqi, Shang Yanlei & Shi Peng fei
2006, 17(2):  390-395.  doi:10.1016/S1004-4132(06)60067-4
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In view of the problems existing in GPS, a non-gyroscope DR is introduced. The operating principle and the algorithm of the GPS/DR device are also presented. By operating measured data synthetically, linear observation equations are obtained for the information fusion algorithm. This approach avoids model error due to linearizing nonlinear observation equations in the conventional algorithm, so that the stability of information fusion algorithm is improved and computation expenses are reduced. Field running experiments show that satisfactory accuracy can be obtained by the proposed navigation model and algorithm for the non-gyroscope GPS/DR device. 
TF/TA2 trajectory tracking using nonlinear predictive control approach
Tang Qiang, Zhang Xinguo' & Liu Xicheng
2006, 17(2):  396-401.  doi:10.1016/S1004-4132(06)60068-6
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The use of a methodology of nonlinear continuous predictive control to design the guidance control law for the aircraft TF/TA2 trajectory tracking problem is emplojed. For the derivation of the predictive control law, by using Taylor series expansion, and based on optimizing a performance index which is a quadratic function of both the predictive value of the state variables and the control inputs, a state variable feedback controller for nonlinear systems is obtained, and it provides a tradeoff between satisfactory tracking performance and the control magnitude requirements. Numerical simulation results for a supersonic fighter aircraft model show the viability of this approach.
Optimal hardware/software co-synthesis for core-based SoC designs *
Than Jinyu & Xiong Guangze
2006, 17(2):  402-409.  doi:10.1016/S1004-4132(06)60069-8
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A hardware/software co-synthesis method is presented for SoC designs consisting of both hardware IP cores and software components on a graph-theoretic formulatioa Given a SoC integrated with a set of functions and a set of performance factors, a core for each function is selected from a set of alternative IP cores and software components, and optimal partitions is found in a way to evenly balance the performance factors and to ultimately reduce the overall cost, size, power consumption and runtime of the core-based SoC. The algorithm formulates IP cores and components into the corresponding mathematical models, presents a graph-theoretic model for finding the optimal partitions of SoC design and transforms SoC hardware/software co-synthesis problem into finding optimal paths in a weighted, directed graph. Overcoming the three main deficiencies of the traditional methods, this method can work automatically, evaluate more performance factors at the same time and meet the particularity of SoC designs. At last, the approach is illustrated that is practical and effective through partitioning a practical system.
Flooding attack and defence in Ad hoc networks *
Yi Ping, Hou Yafei, Thong Yiping, Zhang Shiyong & Dai Zhoulin
2006, 17(2):  410-416.  doi:10.1016/S1004-4132(06)60070-4
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Mobile ad hoc networks are particularly vulnerable to denial of service (DOS) attacks launched through compromised nodes or intruders. In this paper, we present a new DOS attack and its defense in ad hoc networks. The new DOS attack, called Ad hoc Flooding Attack(AHFA), is that intruder broadcasts mass Route Request packets to exhaust the communication bandwidth and node resource so that the valid communication can not be kept After analyzed Ad hoc Flooding Attack, we develop Flooding Attack Prevention (FAP), a generic defense against the Ad hoc Flooding Attack When the intruder broadcasts exceeding packets of Route Request, the immediate neighbors of the intruder record the rate of Route Request Once the threshold is exceeded, nodes deny any future request packets from the intruder. The results of our implementation show FAP can prevent the Ad hoc Flooding attack efficiently.
QoS-aware multicast routing protocol for Ad hoc networks*
Sun Baolin, & Li La yuan
2006, 17(2):  417-422.  doi:10.1016/S1004-4132(06)60071-6
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Ad hoc wireless networks consist of mobile nodes interconnected by multihop communication paths. Unlike conventional wireless networks, ad hoc networks have no fixed network infrastructure or administrative support Due to bandwidth constraint and dynamic topology of mobile ad hoc networks, supporting Quality of Service (QoS) is an inherently complex, difficult issue and very important research issue. MAODV (Multicast Ad hoc Ondemand Distance Vector) routing protocol provides fast and efficient route establishment between mobile nodes that need to communicate with each other. MAODV has minimal control overhead and route acquisition latency. In addition to unicast routing, MAODV supports multicast and broadcast as well. The multicast routing problem with multiple QoS constraints, which may deal with the delay, bandwidth and packet loss measurements is discussed, and a network model for researching the ad hoc network QoS multicast routing problem is described It presents a complete solution for QoS multicast routing based on an extension of the MAODV routing protocol that deals with delay, bandwidth and packet loss measurements. The solution is based on lower layer specifics. Simulation results show that, with the proposed QoS multicast routing protocol, end-to-end delay, bandwidth and packet loss on a route can be improved in most of cases. It is an available approach to multicast routing decision with multiple QoS constraints.
Novel copyright protection scheme for digital content
Fan Kef eng, Wang Meihua, M? Wei & Æ/éáï Xinhua
2006, 17(2):  423-429.  doi:10.1016/S1004-4132(06)60072-8
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A novel copyright protection scheme for digital content is presented, which is a private watermarking scheme based on the watermark embedding in the DCT domain and watermark extraction using independent component analysis (ICA). The system includes the key for watermark extraction and the host image. The algorithm splits the original image into blocks and classifies these blocks based on visual masking, that is, noise visibility function (NVF). Watermark components with different strength are inserted into chosen direct current components of DCT coefficients according to the classifier. The watermark extraction is based on the characteristic of the statistic independence of the host image, watermark and key. Principle component analysis (PCA) whitening process and FastICA techniques are introduced to ensure a blind watermark extraction without requiring the original image. Experimental results show the proposed technique is robust under attacks such as image filtering and adding noise, cropping and resizing. In addition, the proposed private watermarking system can be improved to the application of the DTV content protection system.
Improved algorithm for RDO in JPEG2000 encoder and its IC design*
Xie Xiang Li Guolin , Zhang Chun Zhang hi & Wang Zhihua
2006, 17(2):  430-436.  doi:10.1016/S1004-4132(06)60073-X
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An improved rate distortion optimization (RDO) algorithm in JPEG2000 is proposed. The proposed algorithm is suitable for integrated circuit (IC) implementation and can reduce 30% computational cost. A hardware architecture which includes control unit, memory, divider, data converter is also given to implement the algorithm The circuit based on the improved algorithm is tested on FPGAs and integrated in a JPG2000 chip codec core.
New multi-pattern matching algorithm
Liu Gongshen, Lz Jianhua & Lz Shenghong
2006, 17(2):  437-442.  doi:10.1016/S1004-4132(06)60074-1
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The traditional multiple pattern matching algorithm, deterministic finite state automata, is implemented by tree structure. A new algorithm is proposed by substituting sequential binary tree for traditional tree. It is proved by experiment that the algorithm has three features; its construction process is quick, its cost of memory is small. At the same time, its searching process is as quick as the traditional algorithm. The algorithm is suitable for the application which requires preprocessing the patterns dynamically.
Design for the simulation of space based information network *
Zeng Bin', Li Zitang & Wang Wei
2006, 17(2):  443-449.  doi:10.1016/S1004-4132(06)60075-3
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Ongoing research is described that is focused upon modelling the space base information network and simulating its behaviours: simulation of spaced based communications and networking project. Its objective is to demonstrate the feasibility of producing a tool that can provide a performance evaluation of various constellation access techniques and routing policies. The architecture and design of the simulation system are explored. The algorithm of data routing and instrument scheduling in this project is described. Besides these, the key methodologies of simulating the inter-satellite link features in the data transmissions are also discussed. The performance of both instrument scheduling algorithm and routing schemes is evaluated and analyzed through extensive simulations under a typical scenario.
Novel Newton's learning algorithm of neural networks
Lorcg Ning & Zhang Fengli
2006, 17(2):  450-454.  doi:10.1016/S1004-4132(06)60076-5
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Newton's learning algorithm of NN is presented and realized . In theory, the convergence rate of learning algorithm of NN based on Newton's method must be faster than BP's and other learning algorithms, because the gradient method is linearly convergent while Newton's method has second order convergence rate. The fast computing algorithm of Hesse matrix of the cost function of NN is proposed and it is the theory basis of the improvement of Newton's learning algorithm. Simulation results show that the convergence rate of Newton's learning algorithm is high and apparently faster than the traditional BP method's, and the robustness of Newton's learning algorithm is also better than BP method's.
New multitarget constant modulus array for CDMA systems
Zhang Jidong & Zheng Baoyu
2006, 17(2):  455-457.  doi:10.1016/S1004-4132(06)60077-7
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A new multitarget constant modulus array is proposed for CDMA systems based on least squares constant modulus algorithm. The new algorithm is called pre-despreading decision directed least squares constant modulus algorithm (DDDLSCMA). In the new algorithm, the pre-despreading is first applied for multitarget arrays to remove some multiple access signals, then the despreaded signal is processed by the algorithm which united the constant modulus algorithm and decision directed method Simulation results illustrate the good performance for the proposed algorithm.
Study on cipher propertys of constant weight codes
Lm Bogang
2006, 17(2):  458-461.  doi:10.1016/S1004-4132(06)60078-9
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Constant weight code is an important error-correcting control code in communications. Basic structure of constant weight codes for some arriving at Johnson bound, A(n9 2w, w) , is presented. Some correlative propertys of the codes, the solution of arriving at Johnson bound, and the results on the couple constant code and some constant weight codes are discussed. The conclusion is verified through four examples.
Novel evaluation method of TCP performance over satellite links
Wang Lina & Gw Xuemai
2006, 17(2):  462-467.  doi:10.1016/S1004-4132(06)60079-0
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A novel and efficient method to evaluate the transmission control protocol (TCP) performance over satellite links is presented. A TCP module is divided into three functional blocks, namely data processing, congestion control and error control. The re-established TCP module is easy to update TCP congestion control strategy or error control strategy. With the proposed analysis approach, the interactions between different congestion control and error control mechanisms, as well as the performance of various combination protocols in satellite environments have been investigated. Simulation results obtained through a series of experiments have shown that SNACK-based error control strategy can perform well with any other congestion control strategy. The best performance can be achieved by TCP NewReno congestion control strategy and SNACK-based error control strategy.