Table of Content

20 February 2009 Volume 36 Issue 1

  

Original Articles

Power allocation based on noncooperative game theory in cognitive radio


YANG Chun-gang;LI Jian-dong;LI Wei-ying;CHEN Dong;CHEN Dan

J4. 2009, 36(1):  1-427. 

Abstract ( 2409 )   PDF (618KB) ( 2069 )   Save

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A power allocation method based on the Non-cooperative Power Control Game (NPCG) in cognitive radio networks is proposed. With the concept of pricing factor, a novel cost function based Signal-to-Interference and Noise Ratio (SINR) is as well as a new payoff function designed. By the principle of game theory, we prove the existence and unique of Nash Equilibrium (NE) in our payoff function, and the NE is Pareto Efficiency. Simulation results show that our algorithm is robust and rapid in convergence. By setting an appropriate pricing factor and some other parameters, our algorithm will converge to an NE in about 3~5 iterative operations which can satisfy the real-time requirement. Meanwhile, the throughput of our algorithm is 1~4 times greater than that of the traditional algorithm.


Novel congestion control scheme in optical burst switching networks


GUO Yan-tao1;2;WEN Ai-jun1;LIU Zeng-ji1;HE Yang1

J4. 2009, 36(1):  5-103. 

Abstract ( 2183 )   PDF (810KB) ( 1147 )   Save

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The paper proposes a novel rate-based congestion control scheme in optical burst switching (OBS) networks. Edge nodes monitor congestion situations by periodically sending and receiving resource management packets (RMP／RMP-ACK), which take the congestion information on core nodes in the OBS network along the light path, and adjust the sending rate of data bursts to avoid network congestion. The performance of the proposed scheme is studied by theoretical analysis and computer simulation. Results show that the RMP scheme can effectively control the OBS network congestion.


Novel approach to multi-channel SAR-GMTI channel equalization and moving target detection and location


ZHANG Li-feng;WANG Tong;XING Meng-dao;BAO Zheng

J4. 2009, 36(1):  11-165. 

Abstract ( 2742 )   PDF (1129KB) ( 1083 )   Save

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For an airborne multi-channel SAR-GMTI system and its real data, a novel channel equalization method is presented, on the basis of which a technique for moving target detection(MTD) and location is proposed. This method first realizes circuits calibration by utilizing the leaking signals, and then implements fast and slow time calibration and compensates the channel differences via iteration after range compression, after which MTD is realized by clutter cancellation and imaging and target parameters are obtained by estimating the moving target doppler shift. The channel equalization method needs no priori knowledge about the parameters of antenna and the plane’s movement, and avoids image registration and auto adaptive clutter cancellation method. Thus it requires less computation and it is easy to realize. The experimental result of real data proves that the method can achieve a clutter cancellation ratio of more than 20dB, and that it has a good detection ＆ location performance.


Novel TOA estimation algorithm for OFDM wireless networks


NI Hao;REN Guang-liang;CHANG Yi-lin

J4. 2009, 36(1):  17-214. 

Abstract ( 1949 )   PDF (573KB) ( 1143 )   Save

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For accurate time of arrival (TOA) estimations for the location based services (LBS) in the OFDM wireless networks, a novel TOA estimation algorithm for OFDM is presented. The TOA estimation is separated into the estimation of the integral sampling interval TOA part and the estimation of the fractional sampling interval TOA part. At the receiver, the characteristics of the training symbol in the time and frequency domain are exploited, and the fractional TOA part is obtained with iterative searches. This estimated fractional part is then adopted to mitigate the correlation spectrum spread evoked. Subsequently, the integral TOA part is achieved from this modified correlation spectrum by the leading edge method. Simulation results show that the novel algorithm outperforms the correlation method at SNRs of over 0dB. The estimation accuracy is at least twice that of the correlation estimation at the SNR of 10dB. Meanwhile, the super resolution TOA estimations with a complexity lower than one percent of the complexity, but with a comparable accuracy, of the available super resolution estimations are provided.


Strong anti-robust watermarking algorithm


TONG Ming;YAN Tao;JI Hong-bing

J4. 2009, 36(1):  22-27. 

Abstract ( 1986 )   PDF (1037KB) ( 1246 )   Save

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A digital watermarking algorithm that can resist the strong shear attack is proposed. The embedded strategies include: the watermark is embedded into the basis matrix on behalf of the basic characteristics of the host carrier for the first time, and the theoretical analytical result shows that the algorithm may obtain intelligence and resist shear; the watermark is encrypted spread spectrum modulation to enhance the hidden features; the watermark embedding intensity is adaptively adjusted by a comparison in the PSNR (Power Signal-to-Noise Ratio) between the original image and the synthetic image; the improved PCA(Principal Component Analysis)method is introduced, which strengthens the link between the matrix elements, to improve the algorithm’s convergence speed. Experimental results show that the algorithm is robust to compression, filtering, noise as well as strong shear attacks, and confirm the validity of the theoretical result. The algorithm’s embedding capacity is large and host vector may be an image, audio or others. The algorithm is of general applicability and is a blind watermark scheme.


Resource efficient cooperative wireless system


LI Jing;GE Jian-hua;WANG Yong;QI Li-juan

J4. 2009, 36(1):  28-325. 

Abstract ( 2037 )   PDF (709KB) ( 1212 )   Save

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An adaptive cooperative wireless communication system based on quadrature signaling is proposed, in which each user can transmit its own and the partner’s information simultaneously in the in-phase and quadrature components of a two-dimension modulated signal. The virtual multiple-antenna transmitter generated in this way allows each user to achieve transmit diversity in a distributed fashion, without expanding the bandwidth and boosting the transmit power. With the decode-and-forward(DF) relay channel model, a closed-form bit error rate(BER) performance expression is derived, and then the effect of different power allocation algorithms together with various inter-user and uplink channel qualities on the system performance is investigated. Simulation results show that the proposed system, with an equal power allocation algorithm, provides diversity gains and can achieve a full diversity order at high inter-user channel signal-to-noise ratios(SNRs). Furthermore, additional performance benefits can be obtained by employing an optimum power allocation algorithm.


Design of the asynchronous CLA adder


YANG Yin-tang;XU Yang-yang;ZHOU Duan;MI Xiao-hua

J4. 2009, 36(1):  33-37. 

Abstract ( 2282 )   PDF (612KB) ( 2458 )   Save

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A new adder design is proposed. Combining CLA and asynchronous self-timed techniques,the adder introduces the hybrid handshake protocol and distributes the carry-generating path with the probabilities of the carry chains. It can speed up the asynchronous adder while keeping a low power and area cost. The adder implements the 0.18μm technique of SMIC. Simulation result shows that the 32-bit asynchronous parallel adder achieves the average delay of 0.880932ns. Its speed is 7.33 times faster than the synchronous ripple adder, 1.364 times faster than the asynchronous ripple adder, and 1.123 times faster than the asynchronous carry-select adder. And its area and power cost are less than those of the asynchronous carry-select adder.


High-speed SoC test with switching TAM


XIE Yuan-bin;GAO Hai-xia;PAN Wei-tao

J4. 2009, 36(1):  38-42. 

Abstract ( 1785 )   PDF (519KB) ( 932 )   Save

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There are several TAM architectures with each IP core connected with only one TAM. In this paper, the switching TAM architecture is presented in which each IP core can be connected with one TAM directly or more TAMs with a switching circuit. So some IP cores can be tested by several TAMs, which will reduce the idle time and test time effectively. By 0-1 programming, which is restricted in some given conditions, each IP core is allocated to a TAM, and then a heuristic search arithmetic is used to pick out some appropriate IP cores which could be tested by several TAMs. The test time of our approach on ITC2002 benchmark circuits is less than that of some other approaches.


Method for altitude measurement in the VHF radar under the oblique planar array


DONG Mei;ZHAO Yong-bo;ZHANG Shou-hong;WU Xiang-dong

J4. 2009, 36(1):  43-47. 

Abstract ( 1962 )   PDF (803KB) ( 1368 )   Save

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The algorithms available assume the vertical linear form array model, but the oblique planar array, which brings the mutual coupling between azimuth and elevation, is used in the VHF radar system in actual application. In order to decrease the effect of multipath propagation and mutual couplings under the oblique planar array, the temporal-spatial sequential Maximum Likelihood algorithm is extended to estimate the two-dimension angle for the oblique planar array, which not only avoids the effect of the multipath, but also decreases the mutual coupling by two-dimension scanning and the altitude root mean square error is less than 1％ of the range. Simulation shows the effectiveness of the method.


Quantum constacyclic codes


LI Zhuo;XING Li-juan;WANG Xin-mei

J4. 2009, 36(1):  48-51. 

Abstract ( 2911 )   PDF (476KB) ( 1192 )   Save

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A new class of quantum stabilizer codes is presented. The problem of finding stabilizer quantum-error-correcting codes can be transformed into the problem of finding additive self-orthogonal codes over the Galois field GF(4) under a trace inner product. Based on this connection, one method for constructing quantum constacyclic codes is presented by finding self-orthogonal classical constacyclic codes over the field GF(4) under a trace inner product. Finally, some examples are given. As an application of this method, quantum Hamming codes are constructed. This class of quantum codes includes well-known quantum cyclic codes.


Improvement of AES with minimal implementation complexity


LIU Jing-mei1;ZHAO Lin-sen2;WANG Xin-mei1

J4. 2009, 36(1):  52-57. 

Abstract ( 1623 )   PDF (582KB) ( 1080 )   Save

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It is known that the implementation of AES is asymmetrical, so it will cost more time and space resource. Based on the affine transformation and the MixColumn,an improved AES is presented to reduce the implementation cost. The whole architecture of Rijndael encryption and decryption is symmetrical except for the arranging sequence of the key. When calculating MixColumn or InvMixColumn, only 2 times Xtime multiplication and 4 times addition operation are needed. It slso has the advantage that the encryption and decryption can share the same logic implementation resource, which decreases the implementation cost.


Attestation proxy party-supported remote attestation model and its secure protocol


ZHANG Zhi-yong1;2;PEI Qing-qi1;YANG Lin3;MA Jian-feng1

J4. 2009, 36(1):  58-63. 

Abstract ( 1912 )   PDF (675KB) ( 1144 )   Save

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Since existing remote attestation models lead to an issue of privacy protection of basic configuration details and security attribute features of the terminal platform, an Attestation Proxy Party-supported Remote Attestation (abbr.AP2RA) model and its secure protocol, which have a delegation mode, are presented. The Trusted Third Party is introduced to accept an attestion delegation from the Attestor Party, implements integrity and security attestation of hardware and software on the terminal, and further trustworthily reports the boolean value of the current platform status, thus improving the remote attestation model based on two parties, as well as effectivly protecting the platform privacy of the Attested Party. Moreover, compared with other approaches, the proposed approach is capable of resisting against the message replay attack and collusion attack from the Attested Party together with the tracing terminal platform sponsoring attack on APP, so that it is suitable for resource dissemination and information sharing in the trusted network.


Portable and optimized reversible debugger


LIU Xi-yang;LIU Tao;BAI Zhi-wen;WANG Yan;MU Hao-ying

J4. 2009, 36(1):  64-68. 

Abstract ( 1674 )   PDF (726KB) ( 1149 )   Save

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Due to the low debugging efficiency of large scale software systems and the unrepeatable problem of concurrent program errors, we design a portable and optimized reversible debugging framework based on the Virtual Machine and present a prototype of the reversible debugger called PORD. PORD dynamically translates the executable binary code of the debuggee and instruments code at checkpoints to save execution states. When the debugee runs, the log of execution states is generated dynamically and incrementally. The extended GDB integrated in PORD controls the virtual machine remotely, and restores history states of debuggee according to the state log. If the Instruction Set Architecture of the debuggee is the same as that of the host, dynamic binary translation is replaced by dynamic binary copying for optimization, which enables the debugee to gain a near native speed. Experiments illustrate that PORD provides an efficient and portable software debugging environment at a reasonable speed.


Analysis of the finite element and the reliability of the structures with fuzzy-random parameters based on the two-factor method


MA Juan;CHEN Jian-jun;XU Ya-lan;CUI Ming-tao

J4. 2009, 36(1):  69-739. 

Abstract ( 1897 )   PDF (528KB) ( 1292 )   Save

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The analysis of the finite element of the fuzzy-random truss and the structural reliability are given. Considering the fuzzy-randomness of structural parameters and loads simultaneously, the static analytical model of the fuzzy-random truss is constructed based on the two-factor method, and the structural fuzzy-random responses are presented. The fuzzy numerical characteristics of the structural response are then derived with the random variables’ algebraic synthesis method and the structural reliability is then given too, which is the basis of the structural optimization.


Asynchronous differential space-time cooperative communications in wireless networks


JI Yan-cheng;GAO Yang;GE Jian-hua

J4. 2009, 36(1):  74-79. 

Abstract ( 2040 )   PDF (658KB) ( 1109 )   Save

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In order to mitigate the effect of asynchronism between users and reduce the complexity of the receiver, an asynchronous differential space-time cooperation scheme is presented. Binary phase-shift keying (BPSK) information symbols are divided into two parts and differential-modulated on the in-phase axis (I axis) and quadrature-phase axis (Q axis) respectively, and then coded with the time-reversal space-time block code (TR-STBC). The receiver decodes the signal with the similar method of differential space-time block code (DSTBC), and the decoded signals on the I axis and Q axis are two separate parts of the transmit signal without the asynchronous effect. Through the analysis and simulation of the BER, we demonstrate that the scheme can still achieve cooperative diversity in an asynchronous condition.


Method for building the real time insider threat model


ZHANG Hong-bin1;2;PEI Qing-qi1;MA Jian-feng1

J4. 2009, 36(1):  80-86. 

Abstract ( 1635 )   PDF (798KB) ( 1055 )   Save

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Partial orders of subjects and of objects in the system and mapping relationship between them are defined by using the access control relationship. On this basis, a hierarchy-mapping based insider threat model is developed. The analytic hierarchy process is used to decompose and quantify the insider threat features of subjects and objects in the model. Then full real time assessment is obtained by using the mapping between subjects and objects. Compared with other models, this model improves the precision and objectivity of the quantization by the combination of qualitative and quantitative analysis. Experimental results show that the hierarchy-mapping based insider threat model can effectively assess the insider threat in real-time and can be used to build the insider threat sense system.


Cooperative game theoretic bandwidth sharing scheme for proportional fairness in WLAN


ZHANG Guo-peng;ZHANG Hai-lin;ZHAO Li-qiang

J4. 2009, 36(1):  87-93. 

Abstract ( 1988 )   PDF (649KB) ( 1106 )   Save

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To ensure proportional fairness (i.e., the system bandwidth is shared among the user flows according to their weights) in the IEEE 802.11 wireless LANs, a cooperative game theoretic bandwidth sharing scheme, called PF-DCF, is proposed. By setting the throughput based utility function, the bandwidth sharing procedure is modeled as a cooperative game. In the game, the user flows intend to maximize their utilities under the premise that the system utility is maximized. According to the Nash bargaining solution(NBS) of the game, i.e., the user stations’ optimal packet transmission probabilities to acquire proportional fairness, a bandwidth sharing scheme (PF-DCF) is developed. Simulation results indicate that when using PF-DCF in the ad hoc mode, the user flows can fairly share the system bandwidth by broadcasting their weights information and adjust the backoff parameter (CW_min) to the NBS. In addition, by comparison with 802.11e EDCA, PF-DCF can effectively utilize the channel resource.


Malware propagation model in bluetooth networks


WANG Chang-guang1;2;SHEN Yu-long1;MA Jian-feng1

J4. 2009, 36(1):  94-98. 

Abstract ( 1832 )   PDF (624KB) ( 1014 )   Save

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Based on the analysis of the Bluetooth malware propagation process, an analytical model of its propagation dynamics is established by means of theoretical derivation after abstracting the function of Bluetooth protocols and the mobility of Bluetooth devices into several statistical metrics. The model illustrates that the introduction of authentication mechanism can greatly decrease the propagation speed of Bluetooth malware, which is of great importance to design security Bluetooth protocols and devices. Simulation results show that our model works well.


Fast algorithm for large-scale finite array problems


LAI Ben;LIANG Chang-hong;AN Xiang

J4. 2009, 36(1):  99-105. 

Abstract ( 2127 )   PDF (1034KB) ( 1324 )   Save

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A new algorithm is presented for analyzing the RCS of large-scale finite arrays, using SED(sub-entire-domain functions) to construct the basis functions, FBM(Forward-Backward-Method) in solving the linear equations and DFT(Discrete Fourier Transform) to accelerate the inner product of the vector. Compared with the existing MLFMM which has been widely used, the new method which can guarantee the accuracy of results reduces the computational complexity and the memory storage from O(NlogN) to O(N)， where N is the number of unknowns of the array. This new method can be used to analyze very large finite arrays, and numerical examples are presented to demonstrate its validity.


Method for measuring the characteristic parameter of the circular polarization antenna


SHANG Jun-ping;FU De-min;JIANG Shuai;DENG Ying-bo

J4. 2009, 36(1):  106-110. 

Abstract ( 2590 )   PDF (910KB) ( 3775 )   Save

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A new methodology for measuring the characteristic parameter of the circular polarization antenna using the linear polarization antenna is proposed. The mathematical model of the measurement method is founded based on the decomposition theory of the ellipse polarization microwave. It is easy to obtain the characteristic information on the circular polarization antenna, such as pattern, axial ratio, gain, etc., through the use of two orthogonal measures with a linear polarization antenna, and also a practical testing system is developed. By measuring the circular polarization antenna practically, this method has been proved to be of merits of effectiveness, high automatization, and high measurement accuracy.


Computation and control of RCS for large open-ended cavities


ZHANG Peng-fei;GONG Shu-xi;XU Yun-xue;LIU Ying

J4. 2009, 36(1):  111-115. 

Abstract ( 2008 )   PDF (773KB) ( 1016 )   Save

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The Iterative Physical Optics (IPO) iterative equation is deduced by combining the asymptotic principle of physical optics with the approximations of the surface impedance and reflective coefficient of the PEC surface coated with a thin absorber layer for a large incident angle. The Radar Cross Section (RCS) of an S-shaped circular wave guide and that coated with absorber layer on the inner wall are computed by the fast Iterative Physical Optics method using algorithms of initial value succession and Forward-Backward Iterative. The results show that the absorbent lining and S-shaping of the cavities can lead to 20-dB reduction of RCS for large open-ended cavities.


New detection algorithm for a small moving target in the infrared image


WU Bin;JI Hong-bing;GUO Hui

J4. 2009, 36(1):  116-121. 

Abstract ( 2186 )   PDF (1054KB) ( 1443 )   Save

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A new algorithm based on the Power-Law detector is developed to detect a small moving target under heavy infrared background. Because the fluctuation of the gray-scale value of a pixel in an image occurs when a target passes by, this fluctuation can be viewed as a weak transient signal which can be detected by the Power-Law processor due to its advanced performance on transient signal detection. Experimental results show that the algorithm can reliably detect small targets with SCR larger than 1.


Temperature field characteristic of the soil-vegetation mixed terrain


SHAO Xiao-peng;CHANG Peng-bo;XU Jun

J4. 2009, 36(1):  122-126. 

Abstract ( 1450 )   PDF (645KB) ( 956 )   Save

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The temperature field of the mixed terrain is one of the key problems in the study of infrared radiance characteristics of a target and background. A model of the infrared radiant temperature field of the mixed terrain of soil-vegetation is studied. After analyzing the affecting factors to the temperature field, the mixed terrain of soil-vegetation is defined according to the scope of the coverage fraction of the vegetation. The standard variation and the correlation length of the temperature field of the mixed terrain are analyzed on the basis of the temperature field statistical characteristics of soil and vegetation, respectively. Finally, the changes in these statistical parameters with the coverage fraction of vegetation are discussed, which can provide theoretical basis for infrared scenes simulation and infrared texture generation of the mix terrain. It can be applied to the fields of infrared dynamic scenes simulation and satellite remote scenes efficiently.


Kernel optimal transformation and cluster centers algorithm


ZHAO Feng1;2;ZHANG Jun-ying2;LIU Jing2

J4. 2009, 36(1):  127-133. 

Abstract ( 1581 )   PDF (661KB) ( 1096 )   Save

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The kernel optimal transformation and cluster centers algorithm (KOT-CC) is presented by using kernel methods. In the KOT-CC, all data are mapped to a kernel space via some nonlinear mapping and the optimal transformation and cluster centers (OT-CC) is performed in the kernel space. KOT-CC is a powerful technique for extracting nonlinear discriminant features and is very effective in solving pattern recognition problems which have serious overlap between the patterns of different classes. A fast algorithm for KOT-CC is also proposed based on the basis of the sub-space which is spanned by the training samples mapped into the kernel space, which can improve the efficiency of the feature extraction process and tackle the “large sample size” problem which many kernel methods may suffer from. The experiments based on the data of IRIS, YEAST, GLASS and so on, demonstrate the validity of the proposed new algorithm.


Pull-in study of magnetostatic micro-devices with the reluctance of the magnetic core


GUO Yong-xian;JIA Jian-yuan;ZHANG Da-xing;ZHAO Jian

J4. 2009, 36(1):  134-138. 

Abstract ( 1426 )   PDF (617KB) ( 1027 )   Save

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The reluctance of the magnetic core (RMC) has a great influence on the Pull-in phenomena of the magnetostatic micro-devices (MMD). Based on Ohm’s law and the energy approach, the Pull-in characteristics of different kinds of MMD are analyzed with the consideration of the RMC according to the condition needed when Pull-in phenomena occurr. The results indicate that in the MMF (magneto-motive-force)-controlled model, the vertical and the point-vortical MMD have the same Pull-in characteristics. r increases linearly from 1／3 to 1 with the increase of m from 0 to 2, with r being the ratio of instable displacement to the initial air gap, and m being the ratio of RMC to the magnetic reluctance of the initial air gap. However in the surface-vertical MMD, r₁ increases gradually from 0.4404 to 0.6910 with the increase of m from 0 to 12, where r₁ is the ratio of the instable angle to the maximal rotating angle with the limiting value of r₁ being about 0.7106. In the flux-controlled model, there is no influence of RMC on the Pull-in phenomena of the MMD. No Pull-in phenomena occur in the vertical and the point-vortical MMD, with r₁ in the surface-vortical MMD remaining constant, of about 0.7106.


Feature mutual information method for radar waveform optimization


JIU Bo;LIU Hong-wei;LI Li-ya;WU Shun-jun

J4. 2009, 36(1):  139-144. 

Abstract ( 1707 )   PDF (640KB) ( 1074 )   Save

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Aiming at the waveform design problem of broadband radar for the time-shift sensitivities in identification, a novel method called the feature mutual information method is proposed, which is based on the General Water-Filling method in the presence of additive Gaussian colored noise (AGCN). The separability of multiple targets is increased by maximizing the mutual information between the characteristics of the target and the feature extracted. Experimental results prove the efficiency of the proposed method. Compared to the chirp and Water-filling waveform, the signals designed by feature mutual information method has larger mutual information and better identification performance.


Space-time cooperative scheme based on liner dispersion codes


GAO Ming;GE Jian-hua;JI Yan-cheng

J4. 2009, 36(1):  145-150. 

Abstract ( 2299 )   PDF (615KB) ( 965 )   Save

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The space-time cooperative diversity scheme based on liner dispersion codes outperforms in BER performance the traditional OSTBC cooperative diversity scheme in a high rate system. By selecting different rate liner dispersion codes, the system can trade off between BER performance and data rate. Compared with the system adopting a lower rate liner dispersion code, when the channel condition is good between the source and relays, the system adopting a higher rate liner dispersion code can gain a higher data rate by sacrificing the BER performance just a bit.


Methods updating for the dynamic model with orthogonal vector basis


BAO Hong;ZHAO Dong-zhu;QIAO Yong-qiang

J4. 2009, 36(1):  151-155. 

Abstract ( 1679 )   PDF (528KB) ( 1025 )   Save

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Considering the shortcoming of the matrix updating methods which can not preserve the physical connectivity and has a low computational efficiently, a new updating method with an SVD(singular value decomposition) model is presented based on the theories of multi degrees of freedom vibration and SVD. Compared with matrix updating, this method inducts the matrix recomposing technology to reduce the dimension of the parameter matrix from n×2n to 1×2n, adopts the SVD theory to improve the computational efficiently and processes the updated results to preserve the physical connectivity. Finally, numerical results show the validity and feasibility of the method.


Fast authentication protocol based on the Canetti-Krawczyk model


ZHU Hui;LI Hui;WANG Yu-min

J4. 2009, 36(1):  156-161. 

Abstract ( 2012 )   PDF (539KB) ( 937 )   Save

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Based on the Canetti-Krawczyk(CK) model, a fast authentication protocol which makes use of the public key cryptography and the Message Authentication Code is proposed. The security analysis of the proposed protocol in the implementation plan with the CK model is presented. The results show that the proposed protocol is session-key secure with Perfect Forward Secrecy, Known Key Security and No Key Compromise Impersonation. Moreover, the implementation of the protocol requires just two rounds of communications and a little computation, and it could be an efficient authentication method between users in a network.


Second-order accurate FDTD technique with subgridding modeling in TE mode


DING Hai1;CHU Qing-xin2

J4. 2009, 36(1):  162-165. 

Abstract ( 1788 )   PDF (797KB) ( 1003 )   Save

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A modified subgridding finite difference time domain method (FDTD) is proposed. For the study of the computational domain filled with different dielectric materials and the reasonable division of coarse and fine grids in different dielectric regions, the second-order accurate FDTD technique at the dielectric interface is employed to analyze the tangential electric field components at the interface. Based on Maxwell’s equations in integral form, the second-order accuracy of the tangential electric fields at the dielectric interface is obtained by the establishment of the nonuniform grids and the introduction of the auxiliary magnetic fields. The overall computational accuracy of the modified subgridding algorithm can be improved effectively, without additional computational capacity, consumed time and complexity in programming. Finally, the numerical simulations for some waveguide structures are carried out to validate the better accuracy of the method proposed in this paper than that of the traditional subgridding method and the standard FDTD method.


Structure similarity based clutter metric


HE Guo-jing;ZHANG Jian-qi;LIU De-lian;CHANG Hong-hua

J4. 2009, 36(1):  166-170. 

Abstract ( 2185 )   PDF (742KB) ( 1123 )   Save

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A new clutter metric named C_TSSM(Clutter Metric based on Target Structure Similarity Measure) is developed for electro-optical clutter estimation. With the target structure feature space established, the background image vectors are projected into that space. By measuring the normalized length of the projections, a quantitative estimation of the structure similarity between the background and the target is obtained. C_TSSM has two advantages over those available. First, by emphasizing the spatial arrangement rather than the gray distribution of the pixels, the impact of environment variation on the stability of clutter evaluation is effectively bated. Second, with similarity measurement based on the target structure feature space and no restriction on the background constitution, C_TSSM is applicable for clutter evaluation of different kinds of scene. Experimental results show that C_TSSM can estimate the structure similarity and predict the variation of similarity with distance well.


Multiscale decomposition of image under (B_V,E) frame


LU Cheng-wu1;2

J4. 2009, 36(1):  171-176. 

Abstract ( 1733 )   PDF (1143KB) ( 884 )   Save

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Y. Meyer’s oscillatory pattern decomposition theory is taken as the starting point in this paper. The existence and uniqueness of a class (B_V,E) model are first discussed. And then, a related multiscale decomposition of an image is proposed to reduce the dependence of the balance parameter on the priori information on the oscillatory component. At the same time, its convergence is analyzed. Finally, its algorithm in the wavelet domain is presented by using Lorenz’s project approach. Numerical experiments show that the algorithm can effectively separate the structure component and the oscillatory component from the image, moreover, a hierarchical multiscale representation of the image is also achieved


Alias filter algorithm in router level topology discovery


ZHAO Hong-hua;BAI Hua-li;CHEN Ming;WEI Zhen-han

J4. 2009, 36(1):  177-182. 

Abstract ( 1837 )   PDF (566KB) ( 1010 )   Save

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Router level topology could be discovered from IP level topology based on alias resolution. In order to improve the efficiency of the router level topology discovery algorithm, the instances where there are alias relations are summarized. First, the conditions where there are not alias relations are concluded based on the characteristics of the network structure, and three theorems are brought forward when dealing with alias relations. Then, an alias filer algorithm called AF(Alias Filter) is put forward based on the instances and theorems, which could be used to find all of the conditions of alias relation possible by the Hash technique. Finally, the AF algorithm is verified via the IP level topologies from the Internet covering China, Japan, and Korea, which were discovered by Skitter of CAIDA. The results prove that the algorithm of AF could reduce IP addresses of alias resolution and improve the efficiency of router level topology discovery greatly.


Noise filtering and subdivision precision analysis of Moiréfringe


Lü Meng-jun1;2;YOU You-peng1;GUO Qi1;HE Jun1

J4. 2009, 36(1):  183-188. 

Abstract ( 2000 )   PDF (673KB) ( 1310 )   Save

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The subdivision precision of MoiréFringe is restricted by its quality. In this paper, the adaptive filtering algorithm based on the neural network is used to restrain noise of MoiréFringe.The nonlinear mapping fuction is achieved by using the neural network layer. The step size of the algorithm can be adjusted dynamicly according to the signal’s frequency to meet the filtering request of the signal with a diversified frequency and make the algorithm self-adaptive.On subdividing filtered circle grating MoiréFringe signals by means of the tangent method by 512 times, it is shown that the distinguishment is 0.618″, that the maximal cumulate error is 1.236″, and that the signal quality and the subdivision precision are greatly improved.Because of its wide bandwidth and restraint of linear and nonlinear noises, the algorithm is better than general filtering way and can satisfy the preparation for the subdivision of MoiréFringe.