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Table of Content

15 August 2015 Volume 28 Issue 8
  
    Articles
    Distributed Retro-reflective Beam Focused on Wireless Energy Transfer
    HE Jinmei,WANG Xin
    . 2015, 28(8):  1. 
    Abstract ( 543 )   PDF (939KB) ( 712 )  
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    This paper presents a design of wireless power transmission based on distributed retro-reflective beamforming.The power transmitter consists of two 1×4 antenna arrays,well separated in space.All the 8 antenna elements receive pilot signals broadcasted from a mobile target device,and then jointly focus the wireless power on the mobile device using the retro-reflective scheme.Simulation results show that the scheme of distributed retro-reflective beamforming can track the mobile device's location within a certain region and accurately deliver wireless power onto the device's location.

    Design of a L-band Airborne Transceiver
    WU Liangliang
    . 2015, 28(8):  4. 
    Abstract ( 564 )   PDF (653KB) ( 426 )  
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    According to the request of small dimension,light weight and low power consumption for airborne equipment,an L-band transceiver working in TR time division system is designed by using RF circuit miniaturization and integration technology,high-efficiency power amplifier technology,and integrated rapid AGC technology.The appearance is 65 mm×65 mm×20 mm in size,130 g in weight,and less than 6 W in power consumption.The output power of transmitting channel is≥6 W,and the third-order intermodulation is≤-18 dBc.The gain of receiving channel is up to 85 dB,the noise figure is≤3 dB,and the dynamic range is≥65 dB.The result shows that the transceiver has stable performance and very strong practicability in flight test verification.

    Design of a New Band-notched UWB Antenna
    ZHANG Fan,PAN Jing
    . 2015, 28(8):  8. 
    Abstract ( 569 )   PDF (597KB) ( 607 )  
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    A novel ultra-wideband (UWB) antenna is proposed in this paper to avoid the interference from other systems.This paper presents a strip with unequal width to apply on the UWB antenna in order to achieve dualband-notched characteristics.Except for the two subbands for WiMAX (3.3~3.7 GHz) and the downstream X-band (7.25~8.395 GHz),the antenna's return loss S11 is better than -10 dB at all frequencies.Simulation of the designed antenna shows a good band notched characteristic at frequencies 3.38~3.58 GHz and 7.29~8.13 GHz.

    Design and Simulation of Circularly Polarized Antenna for Miniaturized Beidou Navigation Terminals
    ZUO Dongguang,LUO Hongtao,HU Longtao,LI Fengchen
    . 2015, 28(8):  11. 
    Abstract ( 553 )   PDF (681KB) ( 548 )  
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    A miniature single feed micro-strip antenna of circularly polarization is designed.The antenna achieves good right-hand-circular polarization and the miniaturization design by truncated corners and slotting symmetrically on the square patch.The antenna parameter is simulated and analyzed through HFSS electromagnetic simulation software.The simulation result shows that the impedance bandwidth is 82 MHz when the return loss is less than -10 dB and the bandwidth of 3 dB polarization axial ration is 12 MHz,meeting the requirements of Beidou navigation receiving antenna.The design has the advantages of simple design,easy implementation,and low cost with good prospects.

    A High Gain Vivaldi Ultra Wideband Antenna
    OUYANG Weizhong,ZHOU Yonggang,LI Bonan,XIE Qianqian
    . 2015, 28(8):  15. 
    Abstract ( 577 )   PDF (706KB) ( 612 )  
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    The conventional Vivaldi antenna has the advantage of ultra-wideband,but has poor orientation and gain degeneration at both ends of whole band.This paper presents a high-gain Vivaldi antenna with increased overall gain by loading zero-index metamaterial (ZIM) and rectangular comb-slot structure at axial edges (RSE).The proposed antenna has been designed,optimized and simulated,and antenna samples are fabricated.The simulation and test results are in good agreement.The results show that the return loss is better than 10 dB@4~11 GHz,and gain improvement is obtained at whole band,compared with the conventional Vivaldi antenna.The antenna gain is increased by 2.5 dB at lower frequency band (4~6 GHz) and 1.5 dB at higher band (9~11 GHz).

    A Method of Designing A New Type Power Divider based on Waveguide E-T Junction
    KOU Yang
    . 2015, 28(8):  18. 
    Abstract ( 673 )   PDF (602KB) ( 472 )  
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    This paper points out the deficiency of the traditional power splitters and introduces the principle of the waveguide E-type T junction power divider.On this basis,an improved waveguide E-type T junction power splitter is proposed with the advantages of high isolation,low insertion loss,small size and broad band.The three-dimensional simulation software CST is used in modeling and simulating.The measured results show that the insertion loss is less than 0.12 dB,the return loss is better than 18 dB and the isolation between the two output ports is better than 15 dB from 12 to 17 GHz.

    FPGA Implementation of Absolute Position Sensor Based on Simulink
    CHEN Wenyi,ZHOU Lin,LEI Wuliang
    . 2015, 28(8):  21. 
    Abstract ( 526 )   PDF (958KB) ( 482 )  
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    As the conventional image processing FPGA design has the problem of long design cycle and complex simulation,we propose a hardware design method based on Simulink's powerful image processing capabilities,easy operation,high flexibility and ease of simulation.First we finish the design of functional model,then convert it to a fixed-point model and finally to the HDL model.This method greatly reduces the functional model design cycle due to its pre-image visual simulation,achieving the FPGA implementation of the absolute position sensor within the allowed error range (0.01 millimeter).

    Design of High Order FIR Filter Design Based on FPGA
    JIAO Shuhong,ZHI Yang
    . 2015, 28(8):  24. 
    Abstract ( 534 )   PDF (745KB) ( 454 )  
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    FIR filter is wildly used in digital signal processing.It is difficult to realize high order FIR filters by using software because of large amount of computing.This paper introduces the use of FPGA to implement high order FIR filter with fast convolution structure and deducts the formula of large point FFT decomposition to two-dimensional FFT.According to the above theory,a high order FIR filter with fast convolution structure is designed based on the one-dimensional to two-dimensional FFT using Verilog HDL language.The experimental results show that the high order FIR filter based on FPGA meets the requirements of practice in engineering with high accuracy and speed,low consumption of resources as well as easy adjustment and integration.

    Thermal Design of Relay Monitoring and Control System RF Module for Aerospace Applications
    CHEN Peng,ZHANG Qiang,MENG Xiangguang
    . 2015, 28(8):  29. 
    Abstract ( 506 )   PDF (1136KB) ( 431 )  
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    This article mainly introduced the thermal design method of the Relay Monitoring and Control RF module for Aerospace Applications,put forward thermal design process and implementation method according to application environment of equipment,at the same time thermal simulation is carried out using the finite element method (FEM) on the equipment optimization.On the prototype test,The junction temperature of power devicescan satisfy the requirements of derating for space application,the rationality and feasibility of thermal simulation and implementation method is verified by thermal balance test.

    Method for and Application of Active Radar Track Correlation
    ZOU Qingqiu,YANG Ou
    . 2015, 28(8):  33. 
    Abstract ( 519 )   PDF (581KB) ( 403 )  
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    This paper proposes a method of active track correlation for the alert radar system to deal with the poor association quality of active radars of the traditional distributed correlation structure.This correlation method mainly covers two parts.One is the track correlation structure based on benchmark track.The correlation structure can effectively avoid associated decline in the quality problem caused by the system track disorders,and can quickly recover from errors associated.The other is the correlation judgment method and process.Finally the correlation method application in the information system of a certain alert radar is given with an accuracy of the correlation better than 90%.

    Research on and Design of PWM DC-DC LED Driver
    GAO Jiabao,JIN Pengfei,RUAN Haiqing
    . 2015, 28(8):  36. 
    Abstract ( 556 )   PDF (989KB) ( 463 )  
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    The DC-DC PWM buck topology and closed-loop constant current control are adopted,and the LED driver circuit operating in the CCM mode is designed with LM2575 as the PWM control chip.The actual circuit board is fabricated with less peripheral components and simple structure,suitable for medium and small LED load drive.The performance parameters of the circuit elements and each node are obtained by theoretical analysis,and the DC-DC buck topology is simulated by Simulink.Measurement after debugging shows that the electric has good performance with a load output voltage ripple within 0.1% and power efficiency up to 45.5%.

    A Wireless Signal Acquisition System Based on MSP430 Microcontroller
    CHEN Leiliang,ZHANG Renjie,LIU Hu,LIU Zhen
    . 2015, 28(8):  39. 
    Abstract ( 483 )   PDF (864KB) ( 472 )  
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    In order to understand the wind turbine blade vibration,and then judge its failure type,the paper designs a wireless signal acquisition system with the low power consumption MSP430 microcontroller as the core control unit.Its hardware is composed of the signal processing module,the wireless communication module,and the MSP430 microcontroller control system.Its software adopts modular design.The system is usually dormant and the CPU stops running until interrupted by software requests.The experiment proves that the module design is stable and reliable,with high-speed data transmission,low power consumption and high versatile,and a bit error ratio of only 1%.

    Design of Digital Intelligent Brush Pots Based on STM32
    WANG Xiaolong,MU Chunyang,ZHANG Panpan,CHEN Xuetao
    . 2015, 28(8):  43. 
    Abstract ( 610 )   PDF (1150KB) ( 511 )  
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    In the view of the limited function,lack of interaction and poor usability of the popular brush pot,this paper presents a design and implementation of an intelligent pen container based on the STM32 chip microcomputer,integrating the electronic elements into traditional brush pot by hardware integration.The design contains such modules as the LCD display,a human body inductor,the MP3 decoding and file storage with swappable support and data exchange with Android or IOS based intelligent equipment via Bluetooth.Users can tailor the functions of the brush pot according to their own needs.

    Calibration of Temperature Measurement Based on MCU
    TAO Qingdong,ZHOU Hanyi,HUANG Yi,ZHOU Rulong
    . 2015, 28(8):  47. 
    Abstract ( 540 )   PDF (595KB) ( 520 )  
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    In order to improve the accuracy and stability in aero-engine temperature measurement,a real-time calibration method based on MCU is proposed.The thermal electromotive force is measured by thermocouple,and then amplified and converted into digital by ADC.The relationship between temperature and the measured data are formulated by two steps of fitting the function by MCU.Combined with PC,the method can calibrate the temperature with zero-setting and full-setting.The experimental results show that the calibration method has high stability and portability with a measuring precision up to 0.2 ℃.

    Research on Single-phase APFC with One Cycle Control
    LI Shaolin,DU Qi,JIN Jing
    . 2015, 28(8):  50. 
    Abstract ( 479 )   PDF (634KB) ( 632 )  
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    One cycle control (OCC) of electronic devices is widely used due to its simple structure,high power factor and system stability and reliability.This paper analyzes the typical stage PFC circuit defects,explains the advantages of one cycle control and single-cycle single phase PFC,and establishes a corresponding simulation model.A comparison of the simulation results show that one cycle control of the Boost PFC has a higher power factor and smaller harmonic distortion.

    Three-phase Bipolar PWM Rectifier Model and Control Circuit Design
    WANG Bangting
    . 2015, 28(8):  53. 
    Abstract ( 1026 )   PDF (801KB) ( 516 )  
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    In order to solve the problem of multi-pulse rectifier which the construct is very complex and the input power factor will be reduced when the voltage frequency increasing.The paper adopt the high frequency power conversion technology,and makes the detailed analyze of PWM rectifier control circuit and the model,and introduces the parameter design process according to the design method.Finally,simulation results and test results verify that PWM rectifier presented in this paper can suppress the harmonic current objective,satisfy the DC side voltage of anti-interference and dynamic and static performance,provides a good reference for the design of parameters of PWM rectifier.

    Design of Ultrasonic Distance Instrument with Temperature Compensation Based on Microprocessor
    YU Jiao
    . 2015, 28(8):  56. 
    Abstract ( 566 )   PDF (726KB) ( 781 )  
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    In order to overcome the error of environment temperature fluctuation caused by the ultrasonic ranging,an ultrasonic ranging system is designed using AT89S52 MCU as the core.The system consists of the DS18B20 temperature sensor,HC-SRF05 ultrasonic sensor and LCD1602 digital display circuit.The hardware and software of the system are described in detail.The experiment results show that the measurement system is stable,reliable and highly accurate.

    Research on Multi-path Multi-channel Routing Metrics in Wireless Ad Hoc Networks
    QIAO Ping'an,SHAO Kai,LIU Yunshuang
    . 2015, 28(8):  60. 
    Abstract ( 479 )   PDF (544KB) ( 446 )  
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    Weighted cumulative expected transmission time (WCETT) routing metrics designed for the single channel and single path routing protocol will lead to invalid routing for the multi-path multi-channel routing protocol,thus restricting the cumulative throughput of the whole network.This paper makes a detailed analysis of the existing WCETT routing rules,and on this basis puts forward the routing metric criterion MWCETT (Multi-MWCETT) suitable for multi-path of multi-channel routing protocol.The comparison of the simulation results of the MSR routing protocol applied to the routing rule and its application to WCETT standards MSR protocol shows that the criterion is better in performance than the WCETT criterion.

    D_MMSE-FE Equalization Algorithm for LTE Up Link System
    WANG Lianyou
    . 2015, 28(8):  63. 
    Abstract ( 549 )   PDF (746KB) ( 445 )  
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    A new decision feedback equalizer algorithm which is called Double MMSE Feedback Equalizer and D-MMSE-FE for short was presented to improve the ability of linear equalizer and avoid the high complexity of the traditional decision feedback equalizer.The new algorithm analyses the result of linear MMSE equalizer first and obtains the front and back transfer functions according to the minimum mean square error criterion.A link circuit is employed to improve the ability of equalizer.The new Equalizer is put into use in the TDD LTE uplink SIMO 1×2 receiver as an example,and simulated in the common channels in 3GPP protocol.The results show that the new equalizer improves equalization performance by up to 2 dB compared with the linear equalizer.

    An Improved Localization DV-HOP Algorithm Based on Node Density
    HUANG Junjie,LIU Shixing,GAN Xiaoyu,YIN Kun
    . 2015, 28(8):  67. 
    Abstract ( 519 )   PDF (736KB) ( 513 )  
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    DV-Hop is one of the most common used localization algorithms in range-free algorithms.This algorithm uses the hop distance instead of the actual distance,resulting in localization errors and large energy consumption.The weight assigned DV-Hop algorithm is analyzed,and a new algorithm based on the density of the nodes is proposed.This new algorithm corrects the average hop distance which depends on the neighbor nodes.The simulation shows that the  algorithm improves the precision by 5.3% and reduces energy consumption by 20.7%.

    Design of Distributed Simulation Network Based on DDS Protocol
    MENG Yimin
    . 2015, 28(8):  71. 
    Abstract ( 536 )   PDF (716KB) ( 464 )  
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    The using of simulation models during complex system integration process of civil aircraft is increasing.But because the different data interface and communication protocol,there are much adaptation should be done before the models enter into use.To solve this problem,a distributed simulation network based on DDS protocol is proposed.By utilizing the Ethernet as the transmitting medium in physical layer and involving the IEEE1588 protocol to build up a global synchronization network,a general runtime environment for simulation model is realized.The simulation network reduce the difficulty of using simulation models during system integration process that allows the engineer focus on the parameters they are concerned but not pay more attention to how those parameters are transmitted.

    The Comparative Study of Two SAR Image Algorithm Simulation
    LI Mingli,HUANG Yue
    . 2015, 28(8):  74. 
    Abstract ( 553 )   PDF (566KB) ( 439 )  
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    The real-time performance of Synthetic Aperture Radar (SAR) imaging is closely related with the imaging algorithm used.The paper presents comparing study on two kinds of SAR imaging algorithm in simulation,which are convoluting in time domain and spectrum multipling in frequence domain.Simulation results show that the spectrum multipling algorithm are ten times faster than the other one for a8711240 picture.

    Performance Analysis of Interference Alignment for Multi-cell MIMO Systems
    LIU Yun
    . 2015, 28(8):  77. 
    Abstract ( 556 )   PDF (816KB) ( 753 )  
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    Interference alignment (IA) is one of the promising technologies to solve the co-channel interference in wireless communication systems.It can provide better spatial multiplex gain than other interference management methods.Based on consideration of engineering applications,the realization of interference alignment for multi-cell MIMO system is studied in this paper.Firstly,the performances of classical algorithm based on closed-form solution and typical distributed iterative algorithms in system capacity and convergence are analyzed and compared in independent and identically distributed channel.Secondly,the performances of the algorithms in spatial-correlated channel are simulated and analyzed for the future Massive MIMO technology.Finally,the applications of the algorithms in different communication systems are summarized.Simulation results show that the distributed iterative algorithm based on matrix-projection distance offers the best overall performance.

    Research on Cable Fault Detection Algorithm Based on SSTDR
    LI Lele,JIANG Yang,LIU Yuhong
    . 2015, 28(8):  81. 
    Abstract ( 694 )   PDF (776KB) ( 516 )  
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    In view of the influence of the current accuracy of cable fault detection method for fault detection and localization results and feasibility,this paper uses the Simulink simulation platform for the establishment of Matlab cable fault model.The cable system model is established to study the spread spectrum time domain reflectometry (SSTDR) methods,using direct sequence spread spectrum signal as the testing signal on the cable transmission to judge the fault distance according to the time difference and other parameters.The feasibility of the cable fault location method is verified by simulation of different modulation methods,indicating that the cable fault location based on the BPSK and QPSK has the best effect.

    A Spectrum Feature Based Algorithm for Hiding Information in Digital Audio
    XU Zhi
    . 2015, 28(8):  84. 
    Abstract ( 618 )   PDF (871KB) ( 523 )  
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    Hiding the confidential information in the digital audio signal or file can achieve the effect of camouflage.That is an important approach to information security or secret communication.This paper designs a frequency domain insertion algorithm based on spectrum feature to hide information.It presents the outline process flow of this information hiding algorithm,details the insertion and extraction methods of frequency domain information and the experiment results of transparency,information capacity and robustness.Blind detection can be implemented by this algorithm.The experiments indicate it has good transparency and strong robustness against several kinds of attack with errorless transmission at certain bit rates.

    Optimization of RPPM Fuze Waveform with Genetic Algorithms
    SU Yuxiao
    . 2015, 28(8):  87. 
    Abstract ( 499 )   PDF (928KB) ( 451 )  
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    The quality of waveform design of radio fuze influence its ability of anti-jam directly.Waveform design in random pulse position modulation Doppler fuze involves selection and optimization of a good many parameters.Using these parameters as inputs,ambiguity function of the waveform as the object function,we can optimize waveform parameters with genetic algorithms,which is a through out solution searching algorithms.The result of the optimization indicates that it can improve the performance of anti-jam of radio fuze,and the algorithms is effective and mature.

    Moving Object Detection Based on Inter-frame Differencing and VIBE Algorithm
    LIU Jinli,FU Zhizhong,ZHOU Yang,HUANG Bo
    . 2015, 28(8):  91. 
    Abstract ( 552 )   PDF (870KB) ( 554 )  
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    The video sequence detection of moving objects is susceptible to various interferences.An algorithm for moving object detection based on inter-frame differencing and VIBE algorithm is proposed to detect the moving objects,with Ti TMS320DM6446 as the image processor.The algorithm is implemented on DM6446 hardware platform.The experimental results show that the system can effectively detect moving objects by overcoming such interferences as illumination change.

    An Algorithm for Fire Detection Based on Video Image Analysis
    LI Hongbo,ZHANG Qiliang,YANG Xinghua,SONG Yinglei
    . 2015, 28(8):  94. 
    Abstract ( 574 )   PDF (833KB) ( 468 )  
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    Aiming at the shortage of traditional fire detection technology in large space structure building and complex environment,we develop a fire detection algorithm that can detect fire in early stage based on video image.The algorithm first uses threshold segmentation to segment the video image and obtained suspected flame regions based on the color characteristics of flame pixels.It then computes the circular degree of each suspected flame region and combines its circular degree with its overall characteristics to determine whether it contains flames or not.Testing results show that the algorithm can identify the flame regions from video data with a real-time fashion and can therefore be used for the early detection and prediction of fire.

    Face Recognition Based on PCA Algorithm
    HUANG Huasheng,YANG Aqing
    . 2015, 28(8):  98. 
    Abstract ( 576 )   PDF (782KB) ( 506 )  
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    As a numerical analysis technique,the main application of PCA is to simplify data and reduce data dimension.The introduction of the PCA algorithm to face recognition can extract the most important features of the face image and remove the redundancy and noise of data.In this paper,PCA is used for face recognition to improve the accuracy of recognition.Experiments in the ORL and YALE face database show that the proposed method has a high recognition rate for the face images in the experiments.

    An Optimization Algorithm for Measurement Matrix in Compressed Sensing
    TIAN Xiangling,XI Zhihong
    . 2015, 28(8):  102. 
    Abstract ( 579 )   PDF (1166KB) ( 459 )  
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    In recent years,the emergence of compressed sensing has broken the limit of Nyquist sampling.The original signal can be recovered accurately by observed values,which is much less than the length of original signal.But now the theory of compressed sensing is not mature enough,and the image reconstruction accuracy is not ideal.In this paper,the design method for the observation matrix has been improved by firstly giving weights to the observation matrix according to the characteristics of sparse signal and then making all the elements on the diagonal of the diagonal matrix obtained by the singular value of weighted matrix to be 1.Experimental results show that the value of PSNR has increased by about 1~2 dB at large compression ratios,by almost 8~9 dB at small compression ratios with the improved matrix used as observation matrix of compressed sensing.

    Power System Parameters Matching and Vehicle Performance of Pure Electric Medium Bus
    HAO Dingkun
    . 2015, 28(8):  106. 
    Abstract ( 589 )   PDF (1090KB) ( 465 )  
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    As the main tools of highway transportation,vehicles have a profound influence on environment and traffic.Because the existing vehicle modification technology lacks the corresponding matching research and dynamics simulation analysis,this paper proposes a method for vehicle modification through the corresponding parameters matching and dynamics simulation analysis.The modification of LS6600C type ordinary medium bus and the parameters matching design of power system are discussed.We adopt the vehicle simulation software ADVISOR to establish the corresponding pure electric vehicle power system and the simulation model of the vehicle.The highest speed,acceleration,climbing performance of the vehicle model are simulated and researched.The results show that the continue driving range,maximum speed,accelerating performance and climbing performance of the modified vehicle can satisfy ordinary medium bus operation requirements and service conditions,and this modification technology has a broad prospect application.

    Image Fusion Algorithm Based on Intuitionistic Fuzzy Inference of Multiscale Transform
    NA Yan,LIU Bo
    . 2015, 28(8):  112. 
    Abstract ( 665 )   PDF (758KB) ( 425 )  
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    This paper presents the multi-scale transform of intuitionistic fuzzy fusion method based on medical image,and the effect of four kinds of multi-scale transforms on image fusion are analyzed.The brief procedures of the proposed algorithm is as following:first,performing the Contourlet transform,NSCT transform,Waveletlet transform and Shearlet transform;then fusing the low frequency component and high frequency component by intuitionistic fuzzy fusion method;and finally performing converse transform to obtain the finally fusion image.The experimental results show that the proposed algorithm is superior to the traditional fuzzy fusion algorithm,and that in the transform domain,the fusion results of Contourlet transform are better than those of the other three transforms.

    Local Search Strategy in Scale-Free Networks
    ZENG Cheng,SUN Yaqian,XU Yuzhu,ZHANG Damin
    . 2015, 28(8):  115. 
    Abstract ( 512 )   PDF (679KB) ( 469 )  
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    Based on the advantage of the minimum clustering coefficient search strategy and the greedy algorithm,a minimum clustering coefficient and minimum distance search strategy is designed according to the structure characteristics of the BA scale-free networks,considering the minimum clustering coefficient and the distance metrics which are the influence factor for the search performance.A comparison is made between the minimum clustering coefficient search strategy,greedy algorithm,strategies as random walk and the proposed strategy by simulation.Theoretical analysis and simulation results both show that the proposed strategy achieves a good search performance.

    Mathematical Model of Deformation of an Ancient Pagoda
    QU Zhe,GUO Hui
    . 2015, 28(8):  119. 
    Abstract ( 570 )   PDF (717KB) ( 409 )  
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    Deformation such as tilt,bending or twisting of a thousand-year-old pagoda subject to long-term weight,temperature,wind and other natural factors is studied.This paper analyzes the four sets of observation data during 25 years from 1986 to 2011 based on the space analytic geometry theory and the VC,excel and other software,by which an arbitrary convex polygon center of gravity algorithm is formulated.A quantitative analysis is made to obtain mathematical model  of the tilt,bend,or twisted deformation trends,which provides a basis for the cultural relics sector to develop the necessary measures to protect them.

    A Proposed Scheme for Parking Guidance System Using NFC Mobile Payments
    WU Huihui
    . 2015, 28(8):  122. 
    Abstract ( 584 )   PDF (1146KB) ( 466 )  
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    An intelligent parking guidance system using NFC mobile payments is proposed to solve the limited parking problem with the rapid growth of the number of vehicles.The scheme introduces the searching,reservation and guiding for parking and also includes NFC mobile payments and recommendation of surrounding businesses,making it possible for users to find parking more targeted and efficient,and rendering the payment for parking fees using NFC mobile payments simpler and quicker as well as reducing the cost of parking management,and effectively alleviating traffic congestion.Comparison and analysis show that the scheme is feasible,easy to implement,and of great value in the construction of smart city.

    Design of Silt Grab Hopper Control System Based on STM32 and HMI
    LI Hui,WEI Guoliang
    . 2015, 28(8):  126. 
    Abstract ( 532 )   PDF (743KB) ( 548 )  
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    In view of low automation degree of the silt grab hopper,this paper designs an automatic control system for the Silt grab hopper by using the STM32 Micro-processor as the main controller.Conditioning,acquisition and processing of external signals as well as data transmission are achieved by the rich peripheral hardware of the system.Real-time control of the silt grab hopper and on-line monitoring for its operation condition will be possible with HMI which is connected to the controller through RS485.To enhance the practicability of the system,the remote-control is introduced,which overcomes the disadvantage that the silt grab hopper cannot be operated by a single person.The practical application shows that the work efficiency of the silt grab hopper is greatly improved by the control system with the advantages of good human-computer interaction,high automation,simple operation and good maintainability.

    A New Algorithm for OFDM Multi-Band Joint Spectrum Sensing
    BO Pingping,GONG Rujiang
    . 2015, 28(8):  130. 
    Abstract ( 617 )   PDF (871KB) ( 487 )  
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    In view of the slow convergence speed and low convergence precision of the threshold vector optimization in the multi-band joint spectrum sensing of the OFDM system,the paper presents a method that can optimize threshold vector based on the differential evolution algorithm.According to the multi-carrier digital modulation theory and the excellent frequency selectivity of the OFDM system,the algorithm makes full use of the fast convergence speed and strong global optimization ability of the differential evolution algorithm and guarantees that the optimal threshold vector is obtained by considering sub-channel information when the main user is under certain limited interference.The experimental results show that the proposed algorithm greatly improves the convergence time and convergence precision;and under certain limited interference,the total throughput of the cognitive system reaches the maximum.

    Adaptive Control of Load Tracking Power Generation System
    MA Lixin,LIU Chun
    . 2015, 28(8):  134. 
    Abstract ( 566 )   PDF (767KB) ( 422 )  
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    The smart electric power system requires both fast response to load change and safe and economic operation of the generating sets.The dynamic characteristic of the boiler steam temperature control process varies with load,thus the problem of mutual interference between control parameters and operating parameters.This paper puts forward a model reference adaptive control system capable of load tracking,and derives by the gradient method the parameter adjusting mechanism for quick adjustment of errors in order to ensure system stability and anti-jamming.The simulation results show that the model reference adaptive control system can achieve better dynamic performance parameters and control effect.

    Real-time Detection of Biological Denitrification Parameters Based on μC/OS-II
    LIU Chengliang,WANG Chunfeng,LIN Jinbiao
    . 2015, 28(8):  138. 
    Abstract ( 544 )   PDF (751KB) ( 576 )  
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    In order to realize the real-time detection of biological denitrification parameters and solve the pollution and time-consumption of regular chemical detection methods,we adopt a real-time detection method based on an electrochemistry and embedded system,which can detect in real-time three related parameters:the water temperature,pH and ammonia nitrogen.The theoretical value and the measured value are then compared and analyzed.The experimental results show that the real-time detection system is stable and reliable with good performance,which satisfies the requirement of biological denitrification process real-time monitoring.

    Design of an Automatic Motor Test System Based on Virtual Instrument
    LIU Xiaofang,Fu Yinghua,JIN Jianzhong
    . 2015, 28(8):  142. 
    Abstract ( 588 )   PDF (729KB) ( 437 )  
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    An automatic test system is designed for easer real-time online measurement of motor performance parameters,with LabVIEW graphical programming language as the development platform.The LabVIEW-based system acquires and processes the motor voltage,current,torque and rotational speed signals to obtain the motor characteristic curve for evaluating the comprehensive performance of the motor.The use of LabVIEW guarantees quick and efficient development of the modular intelligent automatic test system with high level of integration for the automatic test of motor characteristic curves.

    Real-time Gesture Recognition with Multiple Cues Based on OpenCV
    SUN Hong,LIAO Lei
    . 2015, 28(8):  145. 
    Abstract ( 556 )   PDF (843KB) ( 481 )  
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    Computer vision-based hand gesture recognition has become a key technique in the realization of new human-computer interaction.This paper proposes a method in the recognition of real-time hand gestures with multiple cues based on OpenCV.The skin area is detected with HSV,and the hand is segmented with gesture geometric characteristics.Then the fingertips are detected by the convex hull algorithm.For distinguishing and recognizing the 12 different gestures defined,a decision tree is adopted combined with the number of fingers,the angle between your fingers aspect ratio features and contour features.Experimental results demonstrate that the proposed method is robust and real-time,and high recognition rate and various gestures are achieved.

    Design and Implementation of the Qt-based Remote Monitoring System Client
    WANG Zhenzhen,ZHANG Qinglei,WANG Chuangang,YANG Liang
    . 2015, 28(8):  149. 
    Abstract ( 554 )   PDF (1178KB) ( 380 )  
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    In the remote monitoring system,the collected data is pushed to multi-terminal,cross-platform GUI interface has become a trend.This paper,takes advantage of Qt,designs a client for the remote monitoring system by using Qt as GUI interface development tool for its powerful graphics interface library and portable characteristics,which displays the waveform,sensor,and video data in a real-time and customized manner.The client interaction platform offers data display of different models with a friendly control interface.The simulation results show that the client has reached the design requirements.

    Evaluation of ADS-B System Operating Reliability
    HU Shuijing
    . 2015, 28(8):  153. 
    Abstract ( 521 )   PDF (748KB) ( 524 )  
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    To comprehensively evaluate ADS-B system operating reliability,we put forward a method which employs T-S fuzzy neural network.In this model,5 reliability indices (mean time to first failure,mean time between failures,mean time to repair,mean availability and repair time rate) are taken as input vectors,and a nonlinear mapping relationship of the reliability comprehensive evaluation is established by T-S fuzzy system.The neural network is adaptively trained to adjust fuzzy rules and membership functions.The comprehensive evaluation model of ADS-B system operating reliability is established base on aforementioned method.The results of simulation and application show that the method is feasible and effective with high computational stability,accuracy and good generalization;and that the evaluation results are objective,accurate and reliable,which is of value in decision-making for improving operation reliability of ADS-B system.

    VFD Visual Inspection System Based on LabVIEW
    WANG Yexiang,DAI Shuguang
    . 2015, 28(8):  157. 
    Abstract ( 614 )   PDF (993KB) ( 436 )  
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    A visual inspection system consisting of a CCD camera,the computer hardware and LabVIEW software platform is designed.The computer controls the camera to collect standard VFDS images as a template,and compares the VFDs images which need to test with the template to determine VFDS segment code number and location.The system is capable of real-time display,storage and playback,greatly facilitating the detection with higher testing speed and detection efficiency.

    Recognition of Defects Nearby Pipeline Welding Based on the Guided Wave Mode Symmetry Curve
    ZHANG Wei,JIANG Yinfang,YAN Youqi,LEI Yulan,LIU Qiuge,CHEN Zhiwei,DU Bin
    . 2015, 28(8):  160. 
    Abstract ( 369 )   PDF (939KB) ( 313 )  
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    The feasibility of using modal symmetry curve for damage identification nearby pipe circumferential welds is discussed.Based on the theory of guided wave mode symmetry detection,the symmetry curve is drawn and the symmetric algorithm for damage identification is formulated.Analysis of the experimental signal of pipeline nearby welding defects shows that the magnitude of symmetry curve rises at the defect sites.And the signal analysis of wavelet packet energy spectrum reveals that the energy of the echo signal focuses on the defects,which verifies the effectiveness of modal symmetrical curve in the auxiliary identification of the pipe circumferential weld defects.

    High-precision Ceramic Plate Electroless Plating Microstrip Multilayer Preparation
    WU Xiaoxia,HU Jianghua,LU Haiyan
    . 2015, 28(8):  164. 
    Abstract ( 459 )   PDF (706KB) ( 348 )  
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    The preparation technology of aluminum alloy slotted waveguide antenna thermal control membranes is studied.Anodic oxidation process was adopted in the experiments for thermal control.The emission and absorption rate indicators of the thermal control coatings by different oxidation process,the influence of oxide film consistency and uniformity on the absorption and the emission rate are introduced.The achievement of both hemisphere emissivity of 0.72~0.74 and the solar absorption index of 0.3~0.35 is discussed.The range of indicators of the aluminum alloy waveguide antenna target thermal control film is determined bye space environment suitability test and analysis.Ultrasonic cleaning is adopted to remove the residual liquid in the waveguide cavity body while meeting the indicator requirements of the thermal control membrane.

    Function and Model of Human Contrast Sensitivity Measurement Under Long Term Optical Radiation
    ZHANG Zhiya,CAI Jinda
    . 2015, 28(8):  167. 
    Abstract ( 449 )   PDF (935KB) ( 362 )  
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    The contrast sensitivity function and model obtained under normal environment no longer applies in the case of long time exposure of the human eyes to high brightness in computer or mobile phone screen radiation (i.e.abnormal visual).The sine grating needed for the experiment is obtained based on the calculation formula of sine grating by matlab programming.Because under different spectral power distribution of contrast sensitivity can have very different values,the contrast sensitivity and CSF curve values of the subjects with visual abnormalities in different spectral power distribution (sunlight and lighting) are obtained by experiments based on LCD display.Then the nonlinear least squares method is used to formulate the CSF model in abnormal visual case.Results show that the spatial frequency to which the human eye is more sensitive and the optical imaging capabilities have changed a lot in case of the abnormal vision,and that the spectral power distribution of the energy-saving lamps have greater impact on human eyes than that of natural sunlight.

    Impact of Hole-craft on Hole Fatigue Life Based on Laser Shock Peening
    JIANG Yinfang,PAN Yu,LI Juan,GAN Xuedong,ZHAO Yong,WAN Quanhong
    . 2015, 28(8):  171. 
    Abstract ( 435 )   PDF (1028KB) ( 431 )  
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    Hole components can easily produce fatigue cracks thus reducing hole fatigue life in the role of alternating load.The paper studies the effect of the drilling technology on the hole fatigue life with aluminum alloy double samples of 7050-T7451,which are subjected to tensile test to observe the fracture fatigue source location,the hole-wall quality and roughness.Experiments show that different hole drilling technologies has little effect on the samples for non-laser shock peening,but it has great impact after laser shock peening.

    Development and Application of Fiber Optic Gyroscopes
    HUO Lei,XIE Liangping,CHEN Yaozhou,WANG Yuandi
    . 2015, 28(8):  174. 
    Abstract ( 630 )   PDF (802KB) ( 415 )  
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    This paper introduces the principle of optical fiber gyro characteristics and development path with emphasis on the technical problems and applications.The product functions are described with Aviation Gyro optical fiber gyros as an example.The future trend of fiber optic gyro is predicted in light of the advancement in modern microelectronics,photoelectronics and signal processing.

    Development and Limitations of Granger Causality in Neuroscience
    JIA Xinxin
    . 2015, 28(8):  178. 
    Abstract ( 487 )   PDF (677KB) ( 369 )  
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    The application of Granger Causality in the field of neuroscience is discussed with an analysis of relevant literature.We introduce the development of Granger Causality,covering its application in time and frequency domain,and nonlinear Causality.According to the definitions of Granger causality,we point out that Granger causality only used partial information of the linear regression model,and suggest the necessity of continuous improvement of Granger causality.

    Enhancement of the Reliability of Video Conferencing Systems
    YE Xun,GE Yuanpeng,LIN Jingying
    . 2015, 28(8):  182. 
    Abstract ( 397 )   PDF (619KB) ( 348 )  
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    Based on an analysis of existing video conference system security,solutions to enhancement of the reliability of video conference system are put forward,covering the filing equipment,hoisting system switching time,and improvement of the management system.

    Applications of Hidden Markov Models in Bioinformatics
    HUANG Ying
    . 2015, 28(8):  185. 
    Abstract ( 508 )   PDF (789KB) ( 398 )  
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    With the example of DNA sequence analysis,the HMMs and its decoding,estimation and learning 3 computational problems are presented.The application of HMMs in bioinformatics is summarized,and the possible development of HMMs in bioinformatics is pointed out.

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