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    20 August 2005 Volume 32 Issue 4
      
    Original Articles

    Analysis of the dynamic model of a rigid-flexible coupled two-level kinetic tuning system
    DU Jing-li;QIU Yuan-ying;DUAN Bao-yan;ZHANG Jie
    J4. 2005, 32(4):  493-496. 
    Abstract ( 1637 )   PDF (252KB) ( 968 )   Save
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    The two level coupled tuning system of feed of the large radio telescope(LT) is composed of a Stewart fine tuning platform mounted in the suspended feed cabin and the cable-cabin coarse tuning system. By combining the dynamic equation for the structural nonlinear finite element of a cable system with that for the multibody system of the Stewart platform, the dynamic model of the rigid-flexible coupled two-level kinematic tuning system is constructed, which is an efficient method to analyze the coupled dynamic problem. The response of the cabin to the movement of the Stewart platform is simulated with the application of the model to the LT50m scaled model, and its results are validated by the experiment. The research serves as a foundation for designing the mass ratio of Stewart to cabin to eliminate the effect of the Stewart platform adjustment on the cabin.

    The improvement and performance analysis of UPMA

    LI Jian-dong;LIU Jing;LUAN Ying-zi
    J4. 2005, 32(4):  497-500. 
    Abstract ( 1727 )   PDF (182KB) ( 821 )   Save
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    To reduce the contention access and polling overhead of the User-dependent Perfect-scheduling Multiple Access (UPMA) protocol, a modified scheme is proposed to allocate the wireless resource adaptively with the user number and traffic load, and a theoretical analysis model has been presented in this paper. The calculated results show that the proposed scheme has a high throughput, low message delay and small message dropping probability.

    Ultra-low voltage operational amplifier based on quasi-floating gate transistors

    YANG Yin-tang;REN Le-ning;FU Jun-xing
    J4. 2005, 32(4):  501-503. 
    Abstract ( 1552 )   PDF (143KB) ( 1155 )   Save
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    The fundamental principle of quasi-floating gate transistors, along with the electrical characteristics and equivalent circuits, are discussed. An ultra-low voltage operational amplifier is proposed using the PMOS quasi-floating gate transistors. Based on the TSMC 0.25μm CMOS process, the whole circuit is simulated by using the Hspice simulator. The simulation result shows that, with a single power supply of 0.8V, the maximal open-loop gain of the amplifier is 76.5dB, the phase margin is 62°, the unit gain band width is 2.98MHz and the power dissipation is only 9.45μW.

    Research on MOCVD temperature control based on Fuzzy-PID

    GUO Run-qiu;XIE Bao-hui
    J4. 2005, 32(4):  504-507. 
    Abstract ( 1550 )   PDF (176KB) ( 834 )   Save
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    According to the temperature characteristics of the reactor and the requirements for temperature control in the MOCVD system, a kind of Fuzzy-PID temperature controller is proposed. Fuzzy-PID can realize the PID parameters on-line self-regulation, normalizing varying PID parameter coefficients into the range between 0 and 1 by using fuzzy control. In addition, the corresponding simulation is given. The results indicate that the Fuzzy-PID controller has better control performance (such as non-linearity, hysteresis and unprecision physical model) than the Smith controller, and can meet the design requirements for the MOCVD temperature controller.

    The analysis of one dimensional microstrip photonic bandgap filters by using the network theory

    LI Bin;ZHANG Yu;LIANG Chang-hong
    J4. 2005, 32(4):  508-512. 
    Abstract ( 1361 )   PDF (394KB) ( 920 )   Save
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    The Network Theory is employed to analyze a type of 1D microstrip PBG filter structure, and a detailed analysis is made to study the influence of the variation of characteristic impedance and the periodic number on the transmission characters. Finally it is concluded that the Microstrip filter structure will have Stop-Band properties only if the characteristic impedance regularly varies along the length of the cell.

    The calculation of electron mobility in GaN

    YANG Yan;HAO Yue
    J4. 2005, 32(4):  513-517. 
    Abstract ( 1512 )   PDF (196KB) ( 1274 )   Save
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    Drift electron mobility, the Hall factor and Hall mobility in GaN are calculated according to Mattiessen's rule as a function of temperature for carrier concentrations with the compensation ration as a parameter on the basis of taking into account the individual average scattering momentum relaxation time of four scattering mechanisms, namely, ionized impurity scattering, polar mode optical scattering, acoustic piezoelectric scattering and acoustic phonon deformation potential scattering which have an effect on electron mobility of GaN. The results show that the total hall factor increases with the temperature below 200K and decreases above 200K. The maximum hall factor obtained is 1. 22 at 200K. In addition, the polar mode optical scattering plays a dominant role in electron mobility for room temperature and above. The acoustic phonon deformation potential scattering is also important at lower temperatures.

    Decision of all-zero blocks before integer transform and quantization in H.264

    SONG Bin;CHANG Yi-lin;ZHOU Ning-zhao
    J4. 2005, 32(4):  518-522. 
    Abstract ( 1728 )   PDF (199KB) ( 821 )   Save
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    We present a fast algorithm for reducing computation complexity of the encoding inter frame in H. 264. In the method, whether all coefficients of a block in transforming domain are zero is examined before integer transform and quantization. Using the above judgment of all-zero blocks, the computation of selecting the inter prediction mode is greatly reduced. Simulation results show that inter macroblock encoding of H. 264 is obviously speeded up by the proposed method. Furthermore, this algorithm is compatible with the H. 264 standard, and can be used in practice.

    A wideband interference nulling method based on subarrays

    CAO Yun-he1;ZHANG Shou-hong1;WANG Sheng-hua2;LI Qiang1
    J4. 2005, 32(4):  523-527. 
    Abstract ( 1639 )   PDF (213KB) ( 773 )   Save
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    In order to suppress wideband interference and make pattern null in the direction of interference, a new wideband transmitting beamforming method for a large scanning angle is presented. The method transmits a narrowband signal to estimate the direction of the target and interference using the MUSIC method and obtain the narrowband weight vector. The wideband optimal weight is obtained by combining the narrowband weight vector and wideband phase compensation weight. The optimal weight can guarantee the high-resolution of the trnasmitting signal and make pattern null. Finally, the computer simulation illustrates the good performance of our method.

    A new scheme for sharing wavelength converters in optical burst switching nodes

    YAO Ming-wu;LIU Zeng-ji;WEN Ai-jun
    J4. 2005, 32(4):  528-531. 
    Abstract ( 1690 )   PDF (174KB) ( 911 )   Save
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    A new Wavelength Converters (WCs) sharing scheme for Optical Burst Switching nodes is proposed, which is called Convert-Only-the-Collided-Part(COCP). According to this scheme only the collided part of a burst is converted to another wavelength, so that the utility of WCs can be improved by reducing the time of occupation. Simulations are made to compare the COCP with available Convert-the-Whole-Burst(CWB) schemes in different sharing architectures carrying various service loads. Results show that the burst loss performance of the COCP scheme is better than that of conventional WC sharing schemes based on CWB, in both Share-per-Link(SPL) mode and Share-per-Node(SPN) mode, and therefore the number of required WCs can be greatly reduced.

    A novel splatting algorithm based on directional reconstruction filter kernels

    WANG Heng;JI Hong-bing;GAO Xin-bo
    J4. 2005, 32(4):  532-537. 
    Abstract ( 1602 )   PDF (431KB) ( 809 )   Save
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    This paper presents a novel splatting algorithm based on directional reconstruction filter kernels to enhance the 3-D object's edges in volume rendering. By utilizing the gradient information in volume data set, our algorithm can adaptively select directional ellipse Gaussian footprint functions. Compared with the traditional splatting, the new splatting algorithm can decrease the overlap of footprint functions, and render more dedicate profiles of the 3-D object at the same speed. In this paper, we present the new splatting algorithm in case parallel and perspective projections are given, and the error analysis in perspective projection. The experimental results prove our algorithm’s effectiveness.
    The research on PDM system technology based on distributed networked-manufacturing
    NIU Hai-jun1;XU Wei-jun2
    J4. 2005, 32(4):  538-540. 
    Abstract ( 1192 )   PDF (107KB) ( 727 )   Save
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    We present a PDM system which supports the enterprise-wide access to product structure data through the World-wide web (WWW). To meet the needs of various enterprises and types of user, the system is based on a product data model which is both flexible and extensible. The system is implemented using the Object Management Group(OMG) object-oriented database management system and using a Common Object Request Broker Architecture(CORBA) Query Service to access produce data that are in heterogeneous environment. This project deals mainly with extensions of the existing Product Data Management(PDM) system to the distributed networked-manufacturing system.

    Study of the shaping reflector for side-fed offset cassegrain antennas

    LIU Shao-dong;LIU Shu-fang;JIAO Yong-chang;ZHANG Fu-shun
    J4. 2005, 32(4):  541-544. 
    Abstract ( 1769 )   PDF (195KB) ( 924 )   Save
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    To improve the wide-angle scanning properties of the satellite antenna, we concentrate on the shaping of the main reflector of the Side-Fed Offset Cassegrain (SFOC) antenna by the method of the ray tracing and the idea of the optimization. In the process of reflector shaping, in order to enhance the flexibility of the expression for the reflector, a two-dimensional cubic B-spline is used to approach the reflector surface according to the initial data. Then, taking the rays’ paths which are equal from every feed to corresponding apertures as the optimization objective, the interprolation data points for the spline function are adjusted with Powell’s direct method, and in this way, the shaped reflector surface is obtained. The analytical results indicate that the 1-D and 2-D gain degradations of the SFOC antenna due to the aberration are reduced remarkably, and thus the wide-angle scanning properties of the SFOC is improved.

    Security analysis of the Chinese wireless LAN standard implementation plan

    ZHANG Fan;MA Jian-feng
    J4. 2005, 32(4):  545-548. 
    Abstract ( 1963 )   PDF (156KB) ( 919 )   Save
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    This paper makes an analysis of the authentication protocol of the Chinese Wireless LAN security standard WAPI(Wireless Authentication and privacy Infrastructure) implementation plan using an enhanced BAN logic—AUTLOG logic. Results show that when the authentication protocol is finished, STA and AP can authenticate each other’s identity and establish a shared pairwise master key. We further conclude that this implementation plan has modified the security issues of the original standard, and thus it can completely reach the authentication goals and satisfy desirable security attributes.

    Compression of the multispectral image by the three-dimensional EBCOT coding algorithm

    XIAO Jiang1;WU Cheng-ke1;LI Yun-song1;XIANG Li-bin2;YANG Jian-feng2
    J4. 2005, 32(4):  549-554. 
    Abstract ( 2273 )   PDF (423KB) ( 1029 )   Save
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    This paper proposes a new multispectral image data compression algorithm (3 Dimensional Embedded Block Coding with Optimized Truncation, 3D EBCOT), which can efficiently reduce spatial and spectral redundancies by applying the 3D Discrete Wavelet Transform (3D DWT), and get the embedded code stream by the three-dimensional Embedded Block Coding with Optimized Truncation(3D EBCOT) algorithm in wavelet transform domain. The novelty of the proposed coding strategy consists of two main parts: first, an unsymmetrical 3 dimensional DWT is used to reduce the redundancies in spatial and spectral domains. Then, after taking a 3D DWT, the coefficients are encoded using the 3D EBCOT algorithm which is expanded from JPEG2000. Numerical experiments on a six-band thematic mapper images show that the reconstructed images after using the proposed algorithm exhibit a better quality and higher compression ratio than the conventional JPEG2000 and KLT-3D SPIHT algorithms.

    Study of the ECR plasma etching process of PZT ferroelectric thin film materials

    LOU Li-fei;XIAO Bin;WANG Jia-you;YANG Yin-tang;LI Yue-jin
    J4. 2005, 32(4):  555-558. 
    Abstract ( 2088 )   PDF (190KB) ( 1090 )   Save
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    Electron cyclotron resonance (ECR) etching of the lead zirconate titanate (PZT) ferroelectric thin films produced via sol-gel process has been performed in SF6 and the SF6+Ar mixtures. The dependence of the etching rate on the total flow rate, gas mixing ratio and microwave power density has been systematically investigated. Experimental results show that the maxima of the etching rate is reached when the gas mixing ratio is about 20%. The surface component X-ray photoelectron spectroscopy (XPS) of PZT thin films indicate that the ECR etching process in SF6 and the SF6+Ar mxtures yield a great decrease in Pb content in the composition of PZT thin films, and that the etching of TiO2 is the major factor in restricting the PZT thin films etching rate.

    An efficient algorithm for OFDM integer frequency offset based on ML estimation

    ZHAO Lin-jing;LI Jian-dong;CHEN Chen
    J4. 2005, 32(4):  559-561. 
    Abstract ( 2054 )   PDF (130KB) ( 1036 )   Save
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    The integer frequency offset will cause a circular shift of the OFDM symbol and consequently degrate the system performance. A novel integer frequency offset estimation algorithm for the OFDM system is proposed, which employs the differential relation among data symbols on different subcarriers in only one OFDM block. The estimator for integer frequency offset estimation is derived based on the maximum likelihood (ML) estimation theory. It is shown that the new algorithm possesses better performance than the conventional method without the increase in complexity.

    RSA-based enhanced oblivious transfer protocol

    ZHAO Chun-ming;GE Jian-hua;LI Xin-guo
    J4. 2005, 32(4):  562-565. 
    Abstract ( 1562 )   PDF (178KB) ( 873 )   Save
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    Based on the RSA signature and (string) oblivious transfer, an enhanced oblivious transfer protocol is proposed which solves the access control problem for an oblivious transfer protocol. The protocol proposed has the property that only the receiver who has the signture issued by the central authority can open the message which he choose and that the sender can not decide whether the receiver has the signature or not. That is to say, the identity of the receiver can not be confirmed after the protocol. Under the decisional Diffie-Hellman assumption the proposed scheme has provable security.

    Study of the estimation of frequencies from the wide band

    WANG Hong-yang;LIAO Gui-sheng;ZHOU Zheng-guang;WU Yun-tao
    J4. 2005, 32(4):  566-569. 
    Abstract ( 1483 )   PDF (182KB) ( 1541 )   Save
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    An algorithm for estimating frequencies from the wide band is proposed. Along with the information provided by the auxiliary channel and the aliased frquencies estimated, we can solve the frequency ambiguity due to sub-Nyquist sampling which is usually adopted to estimate frequencies from the wide band. The method for the estimation of frequencies with sub-Nyquist sampling can reduce the complexity of the overall hardware. In order to reduce the computational burden of the proposed algorithm, a more simplified algorithm is deduced. Finally, simulation results verify the efficiency of this method.

    A low computational complexity ESPRIT method

    HUANG Lei;WU Shun-jun;FENG Da-zheng;ZHANG Lin-rang
    J4. 2005, 32(4):  570-573. 
    Abstract ( 1785 )   PDF (192KB) ( 862 )   Save
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    A low computational complexity ESPRIT method is developed to fast estimate the direction-arrival (DOA) for statistically independent signals. The novel method exploits the training sequences of a desired signal to extract all the directional parameters of the signals and interferences. The proposed method does not need to form the sample covariance matrix or compute its eigenvectors, thus indicating much lower computational complexity. Finally, the effectiveness of the presented approach is verified by numerical results.

    A method of ICA based on estimating the PDF of signals

    LI Xiao-jun1;LOU Shun-tian1;ZHANG Xian-da2
    J4. 2005, 32(4):  574-578. 
    Abstract ( 1716 )   PDF (211KB) ( 1278 )   Save
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    Independent component analysis (ICA) is a method for finding independent components from multivariate (multidimensional) statistical data. Based on the optimal estimation function, a method for the estimation of the score function is developed. By using the Gaussian mixture model , an EM algorithm for approximating the probability density of the data is presented, and a stochastic gradient method is given to separate the independent components. To improve the accuracy and stability of the algorithm, an iterative method for estimating the PDF of data is presented, which can perform the separation of mixed sub-Gaussian from super-Gaussian sources. The performance of the method is shown by computer simulations.

    Computing the input impedance of coax-fed microstrip patch antennas by the two-level discrete complex image method

    HE Xiu-lian;GONG Shu-xi;LIU Qi-zhong
    J4. 2005, 32(4):  579-583. 
    Abstract ( 1677 )   PDF (235KB) ( 884 )   Save
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    The impedance of coax-fed arbitrary shape microstrip patch antenna is investigated by the moment method. The two-level discrete complex image method is used to compute the spatial Green's Function, and thus improves the speed to compute Green's function compared with the direct integral method. The simplified additional mode is introducted to simulate the current distribution near the probe-to-patch junction with the complexity decreased. The intut impedance of two different shape microstrip patch antennas is computed and the numerical result agrees well with the experimental result.

    A calculating method of the effective apparent resistivity for the extremely low frequency transmitting antenna site

    LIU Chao1;2;ZHAI Qi2;XIE Hui2;LIU Qi-zhong1
    J4. 2005, 32(4):  584-586. 
    Abstract ( 1482 )   PDF (115KB) ( 977 )   Save
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    A practical extremely low frequency (ELF) horizontal antenna requires a site of high effective resistivity. This paper describes the relation between the site effective apparent resistivity and the performance of the horizontal transmitting antenna. It is proposed that the length-weighted average of the apparent resistivity along the antenna is a key parameter of the ELF transmitting antenna site characterization. A calculating method for the effective apparent resistivity along the antenna at a inhomgeneous ground is given.

    Single busy tone CDMA—a novel multiple access protocol for the mobile ad hoc network

    ZHOU Xiao-dong;LI Jian-dong;YANG Jun
    J4. 2005, 32(4):  587-592. 
    Abstract ( 2022 )   PDF (285KB) ( 987 )   Save
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    A single busy tone code division multiple access (SBT-CDMA) protocol for the mobile ad hoc network(MANET) is proposed. The RTS/CTS handshake mechanism, busy tone and power control are integrated with CDMA to improve the network performance. The RTS/CTS dialogue is used for the CDMA-code allocation and exchange of the power control information. Base on the difference between the calculated value and measured value of the received busy tone power, a node can ascertain whether the node could initialize an RTS packet transmission. Simulation results show that SBT-CDMA can significantly reduce the packet collision and increase the network throughput with lower energy consumption, and the near-far problem in the CDMA network is also overcomed.

    Structural optimization design of random truss structures based on system reliability

    MA Hong-bo;CHEN Jian-jun;MA Xiao-song;LIANG Zhen-tao
    J4. 2005, 32(4):  593-598. 
    Abstract ( 1602 )   PDF (218KB) ( 876 )   Save
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    This paper constructs an optimization design model for random truss structures with displacements and system reliability constraints. By the method of reliability assignment and reassignment, the difficult problem of disposing the structure system reliability constraints is solved. Based on sensitivity information, the given system failure probability can be disassembled to the sum of all element failure probabilities in the method. And the reliability analysis based on FEM is processed by utilizing the random factor method. In the optimization process, the penalty function method which includes sensitivity information is adopted. Finally, a numerical example shows that the method in this paper is valid and feasible.

    A study of super-resolution processing of targets within a synthetic transmitting beam

    SHANG Hai-yan1;2;CHEN Bo-xiao1;SU Hong-tao1;ZHANG Shou-hong1
    J4. 2005, 32(4):  599-602. 
    Abstract ( 1833 )   PDF (189KB) ( 1303 )   Save
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    For a radar system with only one receiving antenna and the transmitting antenna arrays, in order to improve the target angular resolution, the MUSIC algorithm is applied to process the super-resolution of targets within the transmitting beam. As the signal model of the separated and processed data after being received by a single antenna is equivalent to that of the general receive antenna arrays in a nonuniform way, the super-resolution can be realized, which is proved by simulation results. The super-resolution processing of the synthetic transmitting beam in the receiving terminal surely improves the distinction ability of the radar and the accuracy of the angular measurement.

    Fuzzy K-Harmonic Means clustering algorithm

    ZHAO Heng;YANG Wan-hai;ZHANG Gao-yu
    J4. 2005, 32(4):  603-606. 
    Abstract ( 1575 )   PDF (172KB) ( 801 )   Save
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    Considering the fact that data belong to several clusters to some extent, we import the fuzzy membership of data to clustering analysis, and propose the fuzzy K-Harmonic Means clustering(FKHM) algorithm. The iterative expressions for cluster center and fuzzy membership are deduced respectively. We then describe a unified expression for the iteration of centers, and deduce the conditional probability expression for the centers and data weight functions for FKHM. Finally, the Folkes & Mallows index is used to evaluate the clustering result. Experiment indicates that the fuzzy K-Harmonic Means algorithm can not only overcome the sensitivity to the initial centers, but also improve the quality of clustering results, compared with the K-Harmonic Means.

    A unified traffic engineering scheme in the next generation network

    GUO Yong;XU Zhan-qi;WANG Chun-ting
    J4. 2005, 32(4):  607-610. 
    Abstract ( 1307 )   PDF (142KB) ( 770 )   Save
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    On the basis of the characteristics and quality-of -service (QoS) guarantee of the next generation network (NGN), and overcoming the drawbacks of the present traffic engineering technology, we propose a unified traffic engineering mechanism suitable for NGN, which is based on the self-designed constrained routing algorithm and the Label Switched Path (LSP) preemption scheme. To make the global optimization of network resources possible, not only are offline-and online-routing methods used, but also the multilayer network path selection and the resource provisioning are integrally adopted. Moreover, the preemption mechanism and the resource-scheduling module are utilized to realize the flexible allocation of bandwidth. The main advantages of the proposed solution are the prompt reaction to the traffic changes and the provision of different QoSs for different classes of traffic. This paper mainly stuides the principles of proposed mechanism and its key technologies, and presents the flow chart of the implementation system.

    Space-time block code added spreading sequences and blind decoding algorithm

    CHEN Hao-jun;LIAO Gui-sheng
    J4. 2005, 32(4):  611-615. 
    Abstract ( 1640 )   PDF (222KB) ( 807 )   Save
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    This paper presents a new space-time block code, which introduces orthogonal spreading sequences to the basic structure of the space-time block code, and a blind decoding system, which carries out the decoding without the estimation of the channel. Combined with the orthogonal character of spreading sequences and the orthogonal structure of space-time block code, the noise subspace of the received signal are exploited to achieve the decoding without a knowledge of the channel. Simulation results show that the new space-time block code has good performance at the word error rate (WER) and the bit error ratge(BER).

    ARM detection technique based on the Wigner-Hough transform

    MU Xue-lu;CHEN Jian-chun;ZHANG Hong-kuan
    J4. 2005, 32(4):  616-618. 
    Abstract ( 1534 )   PDF (146KB) ( 877 )   Save
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    A method for ARM detection based on local WHT is proposed. By the estimation of the frequency modulation rate of the missile signal, the amount of calculation and the area of detection are reduced. The efficiency of missile detection is improved by reducing the dimension of the itegral from two to one via formula conversion of the Wigner-Hough transform. Computer simulation shows that an accurate and reliable detection of ARM signal can be achieved in the low SNR environment.

    Influence of the laser's side mode on the performance of 10Gb/s optical quaternary transmission

    HU Liao-lin;WEN Ai-jun;LIU Zeng-ji;YANG Guo-qing
    J4. 2005, 32(4):  619-621. 
    Abstract ( 1356 )   PDF (169KB) ( 923 )   Save
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    10Gb/s optical quaternary and binary transmission systems are simulated separately with emphasis on the influence of the laser’s side mode on the performance of optical quaternary and binary transmission. It is shown that the influence of the laser’s side mode separation and side mode suppression ratio on the performance of optical quaternary is much greater than that on the performance of optical binary, and the laser’s side mode results in larger penalty in the quaternary system than in the binary system. Therefore it is necessary to avoid using multilevel transmission in the practical optical communication systems.

    Design and realization of a temperature follow control algorithm in the heat-supply net

    XUAN Rong-xi;HUANG Xing
    J4. 2005, 32(4):  622-626. 
    Abstract ( 1346 )   PDF (176KB) ( 930 )   Save
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    A temperature follow control algorithm and its realization method in the heat-supply net are presented. By analyzing and predicting changes and trends of outdoor environment temperature, and considering the results of dynamic threshold learning, the control strategies of heat-supply temperature and pressure will be modified promptly and the automatic change of heat-supply temperature with outdoor environment temperature will be realized. Also, the computer control system framework is designed to realize the algorithm. Engineering practice shows that the algorithm can adjust the temperature of heat-supply net effectively, raise the quality of heat-supply and reduce energy consumption.

    State of the arts Cu interconnect and its reliability in ULSI

    HAO Yue1;SHAO Bo-tao1;MA Xiao-hua1;HAN Xiao-liang1;WANG Jian-ping2
    J4. 2005, 32(4):  627-633. 
    Abstract ( 1523 )   PDF (362KB) ( 837 )   Save
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    With the development of higher integration and reliability of IC, the reliability of copper interconnects is more important than ever. In this paper, the key processes of Cu interconnects are analyzed and compared, and the author lay emphasis on the development of the Cu interconnect and Cu vias. The present problems and discussions of fundamental reliability units of Cu interconnects are introduced. Lastly, some methods are given to solve these key problems in Cu interconnects.

    State estimation of band stochastic nonlinear systems

    CHEN Hui-chan;ZHANG Zhuo-kui
    J4. 2005, 32(4):  634-638. 
    Abstract ( 1581 )   PDF (234KB) ( 811 )   Save
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    A band stochastic nonlinear system with the nonzero mean and correlated white noise is discussed. A singular values standard form for band stochastic nonlinear systems with the band singular matrix is given by generalized inverse matrix and singular value decomposition of the matrix. The optimal recursive estimates for predicting and filtering of this system's states are obtained.

    An advanced algorithm for motion vector coding

    HALIDAN·A1;FANG Yong2
    J4. 2005, 32(4):  639-642. 
    Abstract ( 1614 )   PDF (140KB) ( 935 )   Save
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    Some modifications are made on the present algorithm for motion vector coding. In the new algorithm, motion vector coding is divided into three modes according to the difference between horizontal movement and vertical movement. For different coding modes, different variable length code (VLC) tables are used. The simulation results show that the new algorithm reduces 10%~40% bits for motion vector coding and improves the quality of reconstructed image by 0. 05~0. 1dB. In addition, the new method improves the robustness of video bit stream against channel errors and makes the rate controlling operation of video encoders more accurate.

    Low power design of the embedded 64kb SRAM based on the DBL approach

    FENG Guo-chen;LIU Xing-wang;SHEN Xu-bang
    J4. 2005, 32(4):  643-647. 
    Abstract ( 1451 )   PDF (252KB) ( 741 )   Save
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    To meet the low power requirement of the embedded system, a 64kb-embedded SRAM module is designed by adopting the DBL approach and the proposed memory array Divided Block Decoding approach. Compared with the common memory structure, the power decreases by 43%, while the area increases only by 18%.

    An application of the continuous wavelet transform in multivariate function space

    QU Han-zhang1;SONG Guo-xiang2
    J4. 2005, 32(4):  648-652. 
    Abstract ( 1758 )   PDF (211KB) ( 871 )   Save
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    The relation between the partial differential equations and the integral equations are discussed by using the continuous wavelet transform. The result that the partial differential equations can be transformed into the integral equations is obtained and they are equivalent not only in weak topology but also in strong topology.

    Application of the wavelet transform in preprocessing the fingerprint image

    MA Jun
    J4. 2005, 32(4):  653-656. 
    Abstract ( 1347 )   PDF (303KB) ( 953 )   Save
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    The fingerprint is regarded as a kind of biological characteristic of human beings. It has the advantages of uniqueness stability, being able to gather, never being able to be from the subject, etc. It has already become the effective means that the personal identity has discerned. In this paper, the wavelet transform is introduced, and then based on wavelet decomposition and reconstruction, the fingerprint image compressing, getting rid of noise and extracting features are fulfilled. Experimental results have verified that this method is effective in preprocessing fingerprint images.
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