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20 April 2007 Volume 34 Issue 2
Original Articles
A Study of ISAR Imaging of Spatial Diversity Angles
WANG Qi;LI Ya-chao;XING Meng-dao;BAO Zheng
J4. 2007, 34(2): 165-169.
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A feasible algorithm for inverse synthetic aperture radar(ISAR) imaging of spatial diversity angles is proposed. For the interiors and exteriors of echo data sub-apertures of different visual angle, different alignment reference methods are used for envelope alignment, and then a multiple-spot integration method is used for autofocusing. For fusing received signals from various visual angles, an algorithm of using parameterization and non-parameterization combination for interpolation of the sparse aperture is given, and then the cross range FFT is used to obtain target ISAR imaging, which indicates that the algorithm can be applied in sparse aperture imaging of synthetic aperture radar(SAR). Finally the experimental data processing result is given, which demonstrates the effectiveness of the proposed algorithm.
Frequency offset and channel estimation in the MSE-OFDM system
TIAN Bin1;LI Yuan-ying1;WANG Xian-bin2; YI Ke-chu1;ZHANG Wei-dong3
J4. 2007, 34(2): 170-174.
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2754
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Based on frequency-offset estimation for the OFDM system， a frequency-offset estimation technique for the Multi-symbol encapsulated OFDM system utilizing the repetitive signal structure to enlarge the estimation range is implemented. The channel estimation method based on the maximum likelihood principle is proposed， in which the training sequence has a relatively flat spectrum and constant peak to average ratio(PAR). Simulation results indicate that the proposed frequency offset and channel estimation methods are feasible for the MSE-OFDM system and improve its performance with a training sequence flat in the time and frequency domain.
The auxiliary excitation source domain decomposition method and its application in electromagnetics scattering problems
AN Xiang1;Lü Zhi-qing2;LIANG Chang-hong1
J4. 2007, 34(2): 175-180.
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2066
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A highly efficient Domain Decomposition Method (DDM) based on the auxiliary excitation source algorithm is presented for solving electrically large electromagnetics scattering problems. The original domain is partitioned into nonoverlapping subdomains to reduce the computational scale and complexity. To ensure the convergence of the algorithm, an auxiliary excitation source is used to exchange information between subdomains. The resulting linear system of equations for the auxiliary excitation source is established and solved with a fast algorithm. Once the auxiliary excitation source is obtained, the field on each subdomain can be computed independently. Compared with the traditional method, the proposed method can not only improve the computation efficiency greatly, but also decrease the memory requirement and the computational errors significantly. Moreover, it is especially appealing for problems with geometric repetitions, such as, gratings, photonic/electromagnetic band gap structures (PBG/EBG), and frequency selective surfaces (FSS).
Study of neighborhood discovery and link quality estimation in WSNs
DU Jun-zhao;LIU Hui;CHEN Ping
J4. 2007, 34(2): 181-186.
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3132
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We have designed and implemented an algorithm for discovering neighborhood and estimating the timeliness link quality between neighbors using active probing， passive overhearing and WMEWMA(Window Mean Exponentially Weighted Moving Average Estimator). The link layer relay service presented in this paper mitigates the effect of asymmetric links so as to discover more neighbors. We have evaluated the algorithm using both static analysis and simulation through the TOSSIM simulator. Results show that the algorithm is effective, that more than 40% of nodes identify more outbound neighbors and that the percentage of increased outbound neighbors is between 14% and 100%.
A construction method for a family of quantum cyclic codes
LI Zhuo;XING Li-juan;WANG Xin-mei
J4. 2007, 34(2): 187-189.
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The problem of finding stabilizer quantum-error-correcting codes can be transformed into the problem of finding classical self-orthogonal linear codes over the Galois field GF(4) under a Hermitian inner product. A classical cyclic code over the field GF(4) is self-orthogonal with respect to the Hermitian inner product iff the generator polynomial of its dual code is a factor of its generator polynomial. Based on this connection, a class of quantum cyclic codes is constructed by finding corresponding classical cyclic codes. Some examples are also given in detail.
Side information transmission method for peak re-growth reduction in the OFDM system
YANG Gang;HUANG Si-ning;JIANG Yong;LI Yu-shan
J4. 2007, 34(2): 190-193.
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2166
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A novel side information transmission method for PAPR(peak-to-average power ratio) reduction in OFDM(orthogonal frequency division multiplexing) systems is presented, which can avoid the peak re-growth and the change of the structure of original OFDM signals which normally accompany the conventional methods. Simulation shows that the PAPR is reduced about 1.57dB with the new method for the CCDF(complementary cumulative density function) of 10
-3
. At the same time, the accuracy of the side information can be ensured by repeating this certain OFDM symbol. Because the two same symbols have the maximal relativity, this characteristic can be used to achieve frame synchronization. Simulation result shows that the proposed scheme can prominently reduce the occurrence of peak re-growth brought by the conventional methods and help to achieve frame synchronization.
A novel detection algorithm for V-BLAST OFDM systems
ZHAN Jin-long;LIAO Gui-sheng;LI Guo-min
J4. 2007, 34(2): 194-198.
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A novel detection algorithm is proposed for V-BLAST (Vertical Bell Labs Layered Space-Time) OFDM(Orthogonal Frequency-Division Multiple)systems. At the transmitter, different subcarriers are allocated to different layers, which makes subcarriers of different layers mutual orthogonal. At the receiver, the interference suppression based on orthogonal subcarriers is employed. Compared with the conventional serial interference cancellation algorithm which requires that the number of receive antennas be at least the same as that of transmit ones, the proposed algorithm needs only one receive antenna, so the complexity of the receiver decreases remarkably.
The study of M-ary MC-CDMA systems based on orthogonal cyclic codes & pre-equalization
CHU Zhen-yong1;2;3;YI Ke-chu2;ZHOU Quan3
J4. 2007, 34(2): 199-204.
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2012
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A novel M-ary MC-CDMA system in uplink TDD mode is proposed based on orthogonal cyclic codes and pre-equalization. At the transmitter, every mobile user uses the orthogonal cyclic codes as spreading codes, which reduces the spreading codes selection difficulty of the M-ary MC-CDMA system. In order to keep a good orthogonal characteristic among all users’ signals, a pre-equalizer is employed to process the M-ary MC-CDMA signal before being transmitted. The received signal is multiplied by the local sequence, and then the proposed scheme achieves the M-ary despread spectrum and OFDM demodulation at the same time. The results show that the proposed scheme has better bandwidth efficiency and lower computation complexity than traditional M-ary MC-CDMA systems.
Matched filter bound for time-varying multipath Rayleigh fading channels
HAN Fang-ming1;ZHANG Xian-da2
J4. 2007, 34(2): 205-208.
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1967
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By expressing the decision variables of transmission symbols in time-varying multipath Rayleigh fading channels as the Gaussian quadratic vector form, we derive the analytic expression for its characteristic function as a function of the eigenvalues of the weighted covariance matrix. Therefore, the matched filter bound for such channels can be expressed as the sum of the coefficients corresponding to the negative eigenvalues in the partial fraction expansion of the characteristic function. We further compare in matched filtering performance several modulation pulses in time-varying multipath Rayleigh fading channels, with the result that the rectangular pulse can achieve the best time and frequency diversity.
Sawtooth weighted frequency modulated jamming technique for countering LFM radar
ZHANG Yu;YANG Shao-quan;CUI Yan-peng
J4. 2007, 34(2): 209-212.
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A new method is proposed for jamming the linear frequency modulation (LFM) radar, which is based on the feature of the LFM radar signals and is named weighted frequency modulated jamming. The jammer receives the radar signal and modulates it in the frequency domain. Then the modulated signal is retransmitted. It can produce false targets deceptive jamming or cover jamming according to the modulating parameters. This technique requires lower jamming power. Theoretical analysis and computer simulation justify the validity and efficiency of the new jamming technique.
Treatment of false singularities in fringe components of equivalent edge currents
XU Yun-xue;GONG Shu-xi
J4. 2007, 34(2): 213-218.
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1489
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In order to eliminate the false singularities in the Fringe Components of Equivalent Edge Currents expressions, this paper extends the treatment of false singularities of diffraction coefficients in the Physical Theory of Diffraction into the Fringe Components of Equivalent Edge Currents expressions. The part which may produce singularity is departed from the original ones, and then is transformed into more steady expressions in the neighbourhood of singularity points by using the trigonometry exchanging and variable substitution. The reformulated Fringe Components of Equivalent Edge Currents expressions are obtained, thus increasing the numerical stability in neighbourhood of singularity points and eliminating the singularity. Numerical results testifies the validity of the method.
Application of the conformal metamaterial in a monopole antenna
WENG Zi-bin;JIAO Yong-chang;WANG Nai-biao
J4. 2007, 34(2): 219-221.
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A source embedded in a vertically installed cylinder of the low-refractive medium ( n＜1) will be concentrated in a narrow cone in the vertical plane and maintain its omni directivity in the horizontal plane. The ideas developed here are applied to the monopole using the conformal metamaterial cover which is composed of metallic cylinder arrays, the transmission properties of this metamaterial is analyzed by the method of moments, and the monopole antenna system based on the metamaterial cover is measured. Results show that the pattern of the monopole becomes more convergent in the E plane and maintains its omni-directivity in the H plane and that the gain of the monopole is increased from 5.0dB to 7.8dB.
Analysis of mutual coupling in the X-type polarization diversity system
XU Zhi;LIU Qi-zhong;SUN Bao-hua;JI Yi-cai
J4. 2007, 34(2): 222-226.
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A useful model for analyzing mutual coupling (MC) of the X-type polarization diversity system is put forward. The effects of MC in both antennas and circuits on the performance of the system are investigated. The expression for the correlation coefficient for the polarization diversity system is obtained. Therefore the effects of MC on the signal correlation coefficient, mean power ratio and system polarization diversity gain can be investigated more comprehensively. It is concluded that MC could raise correlation but also decrease the mean power difference, thus improving the diversity gain. In addition, the dominant effects of Cross Polarization Discrimination (XPD) on the signal correlation coefficient and mean power ratio of system are illustrated. It is shown that the larger the XPD, the lower the polarization diversity gain will be.
Modeling of the micro-silicon gyroscope
SHAN Guang-bao1;YANG Yin-tang2;LIU You-bao1;ZHU Zhang-ming2
J4. 2007, 34(2): 227-232.
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Lumped behavioral models for the micro-silicon gyroscope is presented. In this method, the micromachined gyroscope is partitioned into many functional components, each of which is modeled using the relative movement theory and energy method, and whose parameterized model coded in Verilog-A is realized. To validate the efficiency of the models, a system-level model for the tuning fork gyroscope composed of functional components models is designed and co-simulated with an electronic circuit in cadence spectre. The simulation result of modal frequency of the gyroscope is accurate to within 1% of the ANSYS analysis. The result also indicates that the transient analysis of the complicated electro-mechanical coupled system is accomplished quickly in this way.
Iterated extended kalman particle filtering
LI Liang-qun;JI Hong-bing;LUO Jun-hui
J4. 2007, 34(2): 233-238.
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A novel particle filter based on the iterated extended kalman is proposed. The iterated extended kalman filter (IEKF) is used to generate the proposal distribution. Because the IEKF can acquire a maximum a posteriori (MAP) estimate of the nonlinear system, and the importance density function integrates the latest observation into system state transition density, so the proposal distribution can approximate the posterior distribution reasonably well. Simulation results show that the new particle filter is superior to the standard particle filter and the other filters such as the unscented particle filter (UPF), the extended kalman particle filter (PF-EKF), the EKF.
A mass detection algorithm based on SVM and relevance feedback
WANG Ying;GAO Xin-bo
J4. 2007, 34(2): 239-245.
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In order to improve the detection performance of mass, which lies on the similar appearance between masses and density tissues in the breast, an support vector machine classifier based on typical features is designed to classify the ROIs. Furthermore, the relevance feedback is introduced to improve the performance of support vector machine. Then a new mass detection scheme based on support vector machine and Relevance Feedback is proposed. Simulation experiments on mammograms illustrate that the support vector machine classifier based on typical features can improve the detection performance of the featureless support vector machine classifier by 5%, while the introduction of relevance feedback can further improve the detection performance to about 90%.
An improved NAS-RIF algorithm
LIU Ning;LOU Shun-tian
J4. 2007, 34(2): 246-248.
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By introducing the monotone smooth logarithm and compounding it with the original cost function, we propose an improved nonnegativity and support constraints recursive inverse filtering algorithm (NAS-RIF) for image restoration. It has been deduced that the search direction remains the same but that the step length decreases in optimizing the improved cost function with the conjugate gradient algorithm from the gradient of the cost function that the FIR filter apporaches the contrary point spread function (PSF) more, and that the estimated image is closer to the original one. The experiment on a blurred text image restoration shows that the mean square error(MSE) of the improved NAS-RIF algorithm has a better convergence, and that the signal to noise ratio is improved.
A novel image mosaic method
YANG Zhan-long;GUO Bao-long
J4. 2007, 34(2): 249-253.
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This paper introduces a new mosaic, called Tile Image Mosaic(TIM), where image tiles with arbitrary shapes are used to compose the final picture. Firstly we merge the edge detected image and the same-size voronoi-diagrams, then adopt the recent Antipole strategy technique about data structure aimed to optimize proximity queries to speed up the search process, and finally search one tile image with the similar shape in the data base to mosaic the voronoi region. Experimental results prove that our algorithm is about 50 times faster than JIM with high image quality.
Fast and efficient iris segmentation
LU Chen-hong;LU Zhao-yang
J4. 2007, 34(2): 254-258.
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A novel iris segmentation method is proposed to remove noises such as eyelashes and eyelids occlusion, and the pupil, which would possibly exist in iris regions and result in poor recognition performance. The accuracy boundary of the pupil is achieved by an active counter model technique. After computing the wavelet transform of the intensity signal of the normalized iris images along horizon direction, the position of eyelid occlusion edge points can be obtained by evaluating the behavior of the wavelet modulus maxima over scales, and the eyelid occlusion regions can be determined by polynomial-fitting. Combined with the eyelashes detecting results obtained by the 1-D Gabor filter, efficient iris segmentation is achieved. Compared with the existing iris segmentation algorithms, the proposed method not only illuminates the aberration influence on the normalized iris image caused by the traditional circular model of the pupil, but debases the implement complexity by avoiding the issues of determining the searching ranges of 4-parameters spaces involved in traditional eyelid boundary detecting. Experimental results on the CASIA iris database images show that the proposed segmentation method can decrease the Equal Error Rate of the recognition system from 8% to 4.4%.
An FM-QCSK chaotic communication system and its performance analysis
ZHANG Yi-wei1;Shen Xu-bang1;Zhu Xiang-dong1;2
J4. 2007, 34(2): 259-263.
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2107
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In the FM-QCSK(Frequency Modulated Quadrature Chaos Shift Keying) communication system, frequency modulation of the continuous-time chaotic signal makes it possible to generate an inherent wideband signal with constant energy per bit. For the chaotic sample function, a set of orthogonal bases can be used to produce the quadrature signal of the chaotic carrier in the frequency or time domain. In the receiver, the reference signal and its quadrature component are directly correlated with the information-bearing part without FM demodulation. In this way, a symbol can once represent 2-bit information to achieve the higher rate of transmission. Simulation results show that the BER performance of FM-QCSK is close to that of FM-DCSK in the AWGN channel, and that compared with traditional periodical carrier modulation, this scheme is robust to the frequency selective fading in the multipath channel.
The design research on the constant current LDO driver of the white light LED
LIU Lian-xi;YANG Yin-tang;ZHU Zhang-ming
J4. 2007, 34(2): 264-269.
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A constant current driver with a very low dropout voltage for the white light LED is designed. A 0.75V band-gap reference, based on the first order temperature compensation and resistive subdivision technology, is constructed in the chip. A 350mA constant driving current can be provided at the supply voltage from 2.7V to 7.0V. When temperature changes from -10℃ to 100℃, the variation in the output current is less than 5.06%. The driving current varies by less than ±0.8% when the supply voltage changes by ±10%. The dropout voltage of the power MOSFET is about 120mV. The power dissipation of the control circuit is less than 1.75mW, and the efficiency of the chip can reach up to 75%.
Multi-signcryption scheme using identity and bilinear pairing
ZHANG Chuan-rong1;2;XIAO Guo-zhen1
J4. 2007, 34(2): 270-273.
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Based on identity and bilinear pairing on the Elliptic Curve, a new multi-signcryption scheme is proposed. In this scheme, the user’s public key is his identity information, such as e-mail address, IP address, telephone number etc. This greatly decreases the cost of building and managing public key infrastructures; the expense of the users’ management of public-key and their certificates is avoided. By using bilinear pairing on the elliptic curve, this scheme can reach the equivalent security levels of the existing multi-signcryption schemes with a short length key and a small computational cost. Moreover, in this scheme, the original signcrypter using his private key decrypts the multi-signcrypted messages and verifies the validity of signcrypted messages and the order of multi-signcryption. Therefore, our multi-signcryption scheme based on identity and bilinear pairing efficiently achieves the cryptographic functions of multi-signcryption.
A new traitor tracing scheme with extra properties
ZHANG Xue-jun1;2;WANG Dong-yong3;ZENG Zhi-yong2;YIN Zhong-hai2
J4. 2007, 34(2): 274-278.
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The session key S is divided into the sum of S<sub>1</sub> and S<sub>2</sub>. Under the condition of a large integer factoring problem, S<sub>1</sub> is decrypted by constructing a special equation(scheme 1). Under the condition of a discrete logarithm problem, S<sub>2</sub> is decrypted by the OPE (Oblivious Polynomial Evaluation) protocol and Lagrange Interpolation Polynomial (scheme 2). On the basis of a linearly additive combination of scheme 1 and scheme 2, a new traitor tracing scheme is formed, which has advantages of both of them, and meanwhile overcomes their disadvantages. It has many advantages such as multi-service, collusion-resistance, asymmetry, black-box tracing, forward-security and backward-security, and its compositive performance is also better than those of existing ones.
A hierarchical IDS model for MANET based on weighted clustering with self-recommendation
LI Sheng-guang1;2;LIU Jian-wei1;2;LI Hui2;ZHANG Qi-shan1
J4. 2007, 34(2): 279-284.
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To solve the problems such as large network consumption and weak expansibility, the paper presents a scheme for layered weighted self-recommendation clustering Intrusion Detection System(IDS) according to the nature of Ad Hoc networks. In the scheme, nodes compete for cluster headers based on their weighted capability parameters, which makes the network layered. In the layered clustering network, cluster members collect IDS data, cluster headers exert judgments, and they collaborate with each other to complete intrusion detection. Then, we analyze in detail the algorithm for selection and the process of self-recommendation and competition of cluster headers. Finally, we use the emulator to simulate the process, and the result shows that the scheme is feasible.
Modeling and simulation of a micro magnetic acceleration switch
ZHU Ying-min;JIA Jian-yuan;TIAN Wen-chao;FAN Kang-qi
J4. 2007, 34(2): 285-289.
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According to the characteristic that the force between a permanent magnetic couple changes nonlinearly with the magnetic displacement, a novel micro acceleration-switch of permanent magnetic force is designed. The dynamic model for the micro switch including the permanent magnetic force, the gas damping force, the contact force and the inertia force is established. The motion differential equations for the mass in several work conditions are presented. The law of the variation of the mass position, the permanent magnetic force, the gas damp force, the contact force between the mass and the contactors in switch work condition is simulated. Results indicate that the micro switch is a damp-varying system and that the damp is determined by the gas between the mass and the encapsulation. The reliability of electrical contact depends on the pressure between the mass and the contactor. The acceleration threshold of the switch is controlled by such parameters as magnetic force and stiffness of the micro cantilever.
ID-based encryption from elliptic curves over ring
ZHANG Ning1;2;XIN Xiang-jun1;3;XIAO Guo-zhen1
J4. 2007, 34(2): 290-293.
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The configuration of ID-based Encryption is analyzed. A new ID-based Encryption is realized with the Elliptic curve over the residue class ring. The group operation on Elliptic Curve Cryptogsystem(ECC) over the ring has the property of RSA trapdoor function and the property of Elliptic Cune Discrete Logarithm Problem(ECDLP) trapdoor function. The two properties are used in the step of Key Extract and Encryption respectively. The new ID-based Encryption has the advantages of good performance and analytical convenience. A pseudo group operation is discussed, and the basic property of this operation is given. With the pseudo point operation, the embedment of the plain text can be easier and more secure.
Unsymmetrical interface design in GALS
XU Yang-yang;ZHOU Duan;YANG Yin-tang;WANG Qing-song;LIAO Feng
J4. 2007, 34(2): 294-297.
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A new point-to-point Global Asynchronous Local Synchronous(GALS) interface is developed. With an unsymmetrical handshake protocol, the communication between the interfaces is realized. And an FIFO is embedded into the datapath of the interfaces. The time utilization of the unsymmetrical interface is more effective than that of traditional symmetrical interfaces. And the interface can achieve high-speed continuous data transmission. Based on the 0.25μm CMOS processes, the highest rates of the sender and the receiver can reach 670MHz and 1.45GHz respectively. The unsymmetrical interfaces can be applied to the System On Chip(SOC) design of the high-speed data rate.
A novel FDTD modeling technique based on triangle mesh-units of an object
YANG Li-xia;GE De-biao;BAI Jian;ZHANG Shi-tian
J4. 2007, 34(2): 298-302.
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A novel technique converting triangle mesh data to Yee’s cell is proposed for finite-difference time-domain(FDTD) computation. In a rectangular coordinate system, based on the model of triangle mesh-units of a target, its FDTD geometry model is obtained by using the projection and cross-point method. At the same time, by recording the electromagnetic parameter of the Yee-cell, the FDTD electromagnetic model is given. In this paper, the typical objects as a perfectly conducting (PEC) sphere and a PEC column are modeled with the aid of this novel technique, and their Radar Scattering Sectior(RCS) are calculated by using the FDTD method. The computational results agree with those by the other numerical methods. Finally, the FDTD model of one missile is presented using the novel technique, and its backscattering RCS is calculated by using the FDTD method. Results show that this novel technique is applicable, in particular, to the FDTD computation for complex objects.
Study of the temperature distribution in the medium in a diode-pumped heat capacity laser
ZHANG Shen-jin1;2;ZHOU Shou-huan1;2;TANG Xiao-jun2;BI Guo-jiang2;Lü Hua-chang2
J4. 2007, 34(2): 303-306.
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The pump distribution and the transient three-dimensional temperature distribution in the medium of a diode pumped heat capacity laser are simulated by the ray tracing method and the finite element method. A diode face-pumped single chip Nd： GGG heat capacity laser is designed. The output power is 1.49kW with an optical-optical efficiency of 24.1%. When the working time is 1.2s, the experimental temperature at the center of surface of heat capacity laser is 81 ℃, and the simulation result is 78.1℃, which coincide well with each other.
A primal-dual infeasible-interior-point algorithm for second-order cone programming
CHI Xiao-ni;LIU San-yang
J4. 2007, 34(2): 307-311.
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In order to overcome the deficiency that initial points should be strictly feasible in interior point methods, a primal-dual infeasible-interior-point algorithm for the second-order cone programming(SOCP) is presented. Based on the optimality conditions and complementarity conditions for SOCP, a new merit function is defined in the algorithm. The smaller the value of the merit function is, the closer the iteration point is to the solution. Without the strict feasibility of the initial points and iteration points, the algorithm is shown to possess both polynomial-time complexity and Q-linear convergence.
An adaptive diffusion filter method based on morphology
SUN Xiao-li;SONG Guo-xiang;JIANG Dong-huan
J4. 2007, 34(2): 312-316.
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According to the different diffusion demand of image in tangential and normal direction, the different diffusion parameter is set. In the tangential direction, the diffusion should be large enough to remove noise efficiently, so the diffusion parameter is 1. In the normal direction, the diffusion demand is different in the interior and edge of an image. We control the threshold of gradient modulus by the morphology method. After substituting the stable threshold by this adaptive threshold in Perona-Malik diffusion parameter, the suitable normal diffusion parameter for the instant image is obtained. The intention is that the interior and edge can be distinguished effectively and the edge information can be preserved as much as possible. Experimental results show that our method has an obvious effect in preserving small details.
Optimal recursive algorithm for generalized discrete stochastic non-linear systems
ZHANG Zhuo-kui;CHEN Hui-chan
J4. 2007, 34(2): 317-321.
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The optimal recursive equation for the generalized discrete stochastic non-linear system is discussed. A singular values standard form for generalized discrete stochastic non-linear systems is given by singular value decomposition of a matrix. Under the two cases, the generalized discrete stochastic non-linear system is decomposed into two subsystems based on the standard form. The optimal recursive algorithm for this system is obtained by state estimation of subsystems. The result shows that this technique efficiently reduces the amount of computation for the generalized singular system.
Optimization and comparison of double-layer planar inductors in high frequency monolithic DC/DC converters
LI Qing-hua;SHAO Zhi-biao;GENG Li
J4. 2007, 34(2): 322-326.
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A global optimization algorithm is presented. The key technologies of geometric programming are applied to the on-chip double-layer inductors used in fully integrated DC／DC converters. This algorithm can globally and efficiently solve the tradeoffs between the inductor competing objectives, such as the quality factor and the area. Based on the physical model, the 10~40nH series square and circlar double-layer planar inductors are globally optimized using geometric programming, and the geometric programming formed analytical expressions are given too. From the optimized results, under the same constrains, the maximum quality factor of the circlar inductors is about 20% higher than that of the square inductors with the same inductance. However, there is not observable difference of resonant frequency between square and circlar inductors.
A router queue management approach based on Nash equilibrium
ZHANG Hui-juan1;2;ZHOU Li-hua1;ZHAI Hong-ming3
J4. 2007, 34(2): 327-330.
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In order to solve the problem of the unfair resource distribution, the router queue management is regarded as an uncooperate game with many players, and based on the game theory, a new router queue management approach with the punishment strategy and the best output avail is presented. The drop arithmetic game model with drop probability strategy and output avail is given, and the drop probability that can assure the game to reach the Nash equilibrium is solved. When the router drops traffics by this drop probability, the output is the best. A schedule arithmetic game with the aim of rewards and punishment is constructed, and the router can provide less service for the greedy traffics and do the best for the other traffics by this arithmetic. The Simulation result indicates that this new approach can effectively solve the unfair resource distribution in the router.
An adaptive similarity learning approach to record linkage
HUANG Jian-bin1;2;JI Hong-bing1;SUN He-li3
J4. 2007, 34(2): 331-336.
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In order to identify the duplicate records in the data extracted from multiple Web sites, a record pair similarity learning approach based on adaptive string distance metrics is presented. Firstly, the approach uses a maximum entropy classifier to label the relationship between each corresponding field pair in the two records. Then a proper distance function is selected for each field pair to measure its similarity. Finally, a Support Vector Machine trained on selected samples is used to classify the record pair in duplicate or non-duplicate one. Experimental results on a range of datasets show that our approach improves duplicate accuracy significantly over traditional techniques and has a good ability of noise data constraint.
