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Table of Content

15 August 2014 Volume 27 Issue 8
  
    Articles
    Development of 3D Visualization Software of Bridge Based on OpenGL
    ZHOU Zhou,ZHANG Licheng,ZHOU Linying,HAO Ruru
    . 2014, 27(8):  1. 
    Abstract ( 744 )   PDF (922KB) ( 867 )  
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    The integration of engineering visualization capabilities into those programs developed with FORTRAN language is a technical problem for many engineering researchers.In this paper,Visual C++ 8.0 is adopted as the development platform.Dynamic link libraries,process communication and shared file are used to achieve information exchange between user interface process and FORTRAN calculation process in the background.OpenGL libraries are used to achieve three-dimensional display for finite element model of bridge and visualization of engineering calculation.These techniques can not only give full play to the advantages of FORTRAN language in scientific computing,but make full use of code resources accumulated by engineering researchers over the years,and enhance the software in human-computer dialogue,interactive processing and graphical display.

    Fingertip Detection and Gesture Identification Based on Kinect Depth Image
    YUAN Fangjian,WANG Yixuan,WANG Yigang,YANG Daotan
    . 2014, 27(8):  6. 
    Abstract ( 933 )   PDF (950KB) ( 904 )  
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    In the development of interactive application systems based on the Microsoft Kinect somatosensory equipment,it is difficult to achieve desired results using traditional human computer interaction devices like mouse and keyboard.A gesture identification method based on fingertip detection is presented to address this problem.The depth information of the image is obtained using the Kinect sensor,and the position information of the palm center using the built-in module of OpenNI SDK.Then the nearest neighbor method is used to achieve hand segmentation and extract the hand shape.After that,the convex hull is obtained using the Graham Scan algorithm optimized with a ray intersection method.Finally,the fingertips are detected using the profile analysis method from the convex hull.On this basis,the recognition of the "grab" gestures is realized using the number of fingertips and the area ratio.Experiments results show that this method can effectively identify the grasp gesture and has good robustness.

    An Improved Neighborhood Average Method for MRI Image Denoising
    WANG Daxi,HU Peng
    . 2014, 27(8):  11. 
    Abstract ( 825 )   PDF (758KB) ( 620 )  
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    The MRI (magnetic resonance imaging) image denoising is an important step in image preprocessing.An improved neighborhood average method is proposed to compensate for the inability of average filtering algorithms to retain image edges and details in the filtering.Firstly,the relationship between the pixel and each template is determined according to the compatibility and similitude principle to judge whether the pixel is an isolated noise point.Then the isolated noise points are processed by the similar gray T neighborhood average method,and the non isolated ones using weighted smoothing template.The experimental result shows that the improved algorithm retains the image edges and details while removing the noise.

    Hand Gesture Detection Technology Based on HOG and SVM
    GUO Wenshuang,WANG Xuefang
    . 2014, 27(8):  15. 
    Abstract ( 738 )   PDF (754KB) ( 653 )  
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    In recent years,hand gesture detection becomes a research hotspot because of its broad application fields.In this paper,histograms of oriented gradient combined with support vector machine are used in hand gesture detection,which reduces the affect of illumination and rotation of gesture.HOG extraction and parameter settings are analyzed in detail,and a better classifier is trained based on HOG and linear SVM.Experiments show that the combination of HOG extraction and SWM can dramatically reduce the limitations on the application of hand gesture detection.

    Medical Image Fusion Based on Multiscale Geometric Analysis
    WEI Yang,NA Yan,DENG Kunming
    . 2014, 27(8):  19. 
    Abstract ( 769 )   PDF (597KB) ( 590 )  
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    Medical image fusion based on multiscale geometric analysis is discussed in this paper.This algorithm first uses contoulet transform to decompose the image,and uses shearlet transform to deal with the low frequency component and wavelet transform to deal with the high frequency components.All the components are fused together and the final image is obtained by inverse contourlet transform.Experimental result shows our method improves the information entropy and average gradient of the image with better image singularity.

    Algorithm for Pedestrian Detection Based on Monocular Vision
    HAN Yonggang,ZHAO Weikai
    . 2014, 27(8):  22. 
    Abstract ( 683 )   PDF (817KB) ( 640 )  
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    Pedestrian detection system is the pedestrian protection system in advanced driving-assistant system,which can effectively reduce pedestrian injury.Texture symmetry degree is currently the most proper feature that can describe pedestrians.A linear detection method is proposed by extracting the region of interest based on texture symmetry degree to effectively reduce the influence of small textures,such as shadow and leaves.The regions of interest are verified by histogram features of gradient direction and support vector machine method.Experiments show that the proposed method can significantly reduce false alarms and missing alarm without affecting the detecting speed.

    Research on Domain Framework for Science and Technology Project Management System
    CHEN Shuai,XU Xiaoliang
    . 2014, 27(8):  26. 
    Abstract ( 697 )   PDF (1019KB) ( 626 )  
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    In view of the lack of full life-cycle management and poor reusability and extensibility of current IT project management systems,this paper proposes a domain model for IT project life cycle management with a design of loosely coupled POJO core domain entities and a dynamic and flexible object combination technology to meet the individual needs or management.Custom label technology is introduced as the technical specifications of page codes.The practical application shows that the framework effectively improves the standardization,reusability and scalability of the system design.

    Design and Implementation of Vehicle Monitoring System
    LIU Xinran,SUN Wanrong,GAO Haofei,HAN Ming
    . 2014, 27(8):  30. 
    Abstract ( 769 )   PDF (812KB) ( 648 )  
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    A vehicle monitoring system is developed by the technologies of GPS,GPRS and JMF.The system implements GPS terminal data acquisition and timely shows the actual position of the vehicle in the electronic map.And it can real-time video monitor the trunk road traffic and analyze traffic flow.The realization of the main functions is given in detail.It can not only accurately locate the actual location of the vehicle,but also provides a detailed analysis of traffic flow for the vehicle management department and owners by monitoring,thus easing the traffic pressure with scientific vehicle management.

    Reed-Solomon (255,239) Encoder and Decoder Based on FPGA
    MENG Kai
    . 2014, 27(8):  33. 
    Abstract ( 811 )   PDF (708KB) ( 661 )  
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    The Reed-Solomon code is a non-binary BCH code,and the RS code can correct not only random errors but also burst errors.It is widely used in the communications and data storage systems.This paper introduces the method of decoding to improve the reliability in high-speed data storage systems.RS timing simulation shows that the decoder can achieve maximum correction.

    Research on and Simulation of the Polarization of Electromagnetic Wave
    YANG Lin
    . 2014, 27(8):  35. 
    Abstract ( 661 )   PDF (829KB) ( 888 )  
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    The polarization of electromagnetic wave has been applied widely in many areas.For a better understanding of the law of the propagation and the pattern of the polarization of electromagnetic wave,many different kinds of polarized waves are simulated and modeled in the software,with intuitive animated variation of the different kinds of polarized waves with time to stimulate interests of the students.The applications value of the polarization of the electromagnetic wave is discussed in detail.

    Research on and Implementation of ZigBee Home Networking
    HE Zhinan,SONG Xuwen,SHEN Dongdong,SHI Ting
    . 2014, 27(8):  36. 
    Abstract ( 727 )   PDF (706KB) ( 949 )  
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    Z-Stack is a ZigBee protocol released by TI.This paper presents a simple,practical home networking method based on Z-Stack.The problems of ZigBee networking and controlling can be solved by the combination of PANID settings,access time window settings and network state storage.The proposed networking technology is implemented in a home health care system,which proves simple and reliable.

    Bad Block Management of the NAND Flash Based Solid State Drive
    TANG Rui
    . 2014, 27(8):  40. 
    Abstract ( 706 )   PDF (513KB) ( 659 )  
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    Bad blocks on NAND Flash based solid state drives cannot be used to store data,thus the need for bad block management.A bad block table is built with one bit for one block,and then a physical block table is converted from logical blocks according to the bad block table with one logical block matching several different physical blocks.The converted physical block table can prevent the upper from using bad blocks and ensure the reliability and safety of data storage.

    Environment Temperature Monitoring System Based on Wireless Sensor Network
    HAO Sulan,QIAO Gangzhu,TAN Ying
    . 2014, 27(8):  43. 
    Abstract ( 820 )   PDF (792KB) ( 726 )  
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    With the temperature data acquisition as an example,an environmental monitoring system based on wireless sensor network technology is designed and implemented which can acquire real-time parameters of the ambient temperature on the platform of TinyOS.Experimental results show that the system can accurately detect the temperature change of the environment with the advantages of stability,accuracy,reliability and convenience.

    Analog Circuit Fault Diagnosis Based on Wavelet Transform and BP Neural Network
    HUANG Ruke,LIANG Tiansheng,YU Hanhua
    . 2014, 27(8):  46. 
    Abstract ( 805 )   PDF (654KB) ( 574 )  
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    This paper presents a systematic fault diagnosis method for analogue circuits based on the combination of wavelet transform and modified BP neural network (BPNN).With the wavelet decomposition as a preprocessor,the feature information is extracted by wavelet de-noising and normalization and applied to the BPNN.The method reduces the number of inputs to the neural network and improves the convergence speed and the ability to detect faults.Simulation results show that the scheme locates faults exactly with improved network structure and fault diagnosis precision and speed.

    Discrimination of Counterfeit Imported Electronic Parts
    GAO Jinhuan
    . 2014, 27(8):  50. 
    Abstract ( 594 )   PDF (928KB) ( 848 )  
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    Counterfeit production may bring big trouble if used in project.This article discusses the methods for discriminating counterfeit products by their characteristics such as the encapsulation appearance,exterior marks,fixed leads,internal structure,and layout of die.It provides useful references for screening test before applied in project.

    Design of ALC for Microwave Power Amplifier
    HAN Pengwei
    . 2014, 27(8):  53. 
    Abstract ( 732 )   PDF (653KB) ( 1047 )  
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    Lots of designs of ALC are complex and costly.In this paper,a simple and low cost ALC is presented,which is composed of detection circuit,voltage controlled attenuator circuit and differential control circuit;and then the principles and circuit design of each part of the circuit is described in detail.ultimately the ALC loop achieve the output power flatness of 0.15 dB in more than 10% bandwidth of S-band,and output power variation is only 0.2 dB under the input signal 5±5 dBm.

    Variable-frequency and Stable Amplitude Signal Source Based on DDS
    ZHOU Jingyu,LIN Fanqiang,XU Lei
    . 2014, 27(8):  57. 
    Abstract ( 747 )   PDF (993KB) ( 708 )  
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    A signal source capable of adjustable sinusoidal and square waves with stable range and reliable precision is designed based on the DDS with a single-chip as the control.The elliptic filter is used to remove the high frequency noise and stabilize the signal at the output,and the B-free power amplifier circuit to improve system load capacity.The hardware circuits are described and tested.The peak-to-peak value is continuously adjustable 0~20 V on a load of 50 Ω.The system has the advantages of simple circuit,powerful functions and good expandability.

    Design of a Pump Room Signal Conversion Circuit Based on LPC2294
    ZHANG Zhongmin,SUN Mingjun
    . 2014, 27(8):  61. 
    Abstract ( 722 )   PDF (1023KB) ( 622 )  
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    With the development of Shipbuilding industry,especially the continuous increasing of microcomputer-based control technology,various kinds of smart sensors are widely used in ship surveillance.The paper proposes a design of pump room signal conversion circuit which transforms the pressure values of marine pump coming from pressure sensor to the controller chip LPC2294.The packaged data are sent to Ethernet via the Ethernet controller.The paper introduces the hardware and software design in detail and verifies the effectiveness of the circuit by experiment.The design presents good performance of early warning about marine pump's abnormal condition,and meets the requirement of mariner surveillance in long distance.

    One or Two Radar Installation System Range Research and Design of Signal Processing Circuit
    SHI Guoyong
    . 2014, 27(8):  67. 
    Abstract ( 1315 )   PDF (729KB) ( 882 )  
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    He installed the system in the one or two radar,Azimuth signal processing circuit is often due to lightning damage,By assembling two radars are not working properly,Impact of civil aviation flight safety,Analysis of a range of signal processing circuit design article,After testing,azimuth processing circuit cancompletely replace the original radar,Ensure continuous radar.

    Design of a Compact Dual-frequency Circularly Polarized Microstrip Antenna
    CHAO Chunxiao
    . 2014, 27(8):  70. 
    Abstract ( 688 )   PDF (604KB) ( 449 )  
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    The design of dual-frequency circularly polarized microstrip antenna fed by a single probe is studied.Miniaturization is realized by using slots,and broadband covering by loading the antenna with a patch.The proposed antenna is simulated by HFSS and the results of VSWR,AR,radiation pattern and gain are given,which shows that the antenna design is effective and feasible.

    Design of an 18 GHz Double-H Shaped Slot Lens Antenna
    SUN Qi,SHAN Gang,LI Rong
    . 2014, 27(8):  72. 
    Abstract ( 628 )   PDF (791KB) ( 620 )  
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    This paper proposes a new slot lens antenna with a microstrip patch antenna loaded lens structure,that is,the double H-shaped slot coupled feed,to achieve circular polarization excitation.An appropriate dielectric lens antenna structure is adopted in front of the antenna to properly press the antenna beam and improve the gain,VSWR,and axial ratio.The antenna has the advantages of compact structure,simple power supply,and easy manufacturing.

    Design of the 1553B RT Based on the DSP System
    LIU Haihong
    . 2014, 27(8):  76. 
    Abstract ( 674 )   PDF (505KB) ( 770 )  
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    In this article,the functions and characteristics of BU-61580 is described,which is a complete integrated interface chip for MIL-STD-1553B.Then taking 16-BIT-BUFFERED mode as an example,the method of hardware design are presented for the MIL-STD-1553B based on the DSP,using the BU-61580 interface chip.Finally,a case is given to show the initialization process and workflow of the software in the BC、RT work mode.

    Four Antenna Cruciform Array Interferometer Signal Arrival Angle of Radiation
    WU Qin,HU Min,ZHANG Cheng
    . 2014, 27(8):  79. 
    Abstract ( 745 )   PDF (647KB) ( 642 )  
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    By analyzing the basic characteristics of spaceborne applications,a finding method with phase interferometer of four antenna cruciform array is proposed.From a single station passive location departure,the time difference of arrival angle signals between three interferometers relative to a reference interferometer are analyzed with three signal phases obtained.But the actual value of the phase difference measurement interferometer is blurred.A signal simulator software design is proposed,which interacts with DSP via the USB,and transmits the data of all pulses when the aerial platform passes a target.

    Multi-chip High-speed D/A AD9739-based Multi-channel Signal Simulator
    MENG Qinghe,ZHANG Gang
    . 2014, 27(8):  82. 
    Abstract ( 696 )   PDF (757KB) ( 532 )  
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    Multiple antenna array is often applied in the detection and location system,in which the phase change rate is commonly used in single observer passive location of the observation parameters.This paper presents a multi-chip-based high-speed AD company 2.5 GSample·s-1D/A converter AD9739 with DDS multi-channel signal simulator.Tests show that the simulator can achieve realistic simulation of phase change of the wideband linear frequency modulated signal waveform received by the multi-element antenna array.

    Analysis of Optimal Scheme of Direction Finding Cross Station Distribution
    XIE Xin
    . 2014, 27(8):  85. 
    Abstract ( 784 )   PDF (1115KB) ( 506 )  
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    An in-depth analysis is made of the basic principles of location,its precision and optimal embattle of direction finding cross location based on multi-stations scene.Furthermore,the optimal number of sites and the influences of various factors on positioning precision under the condition are analyzed.Finally,the optimal distribution of the target direction based on the station and the optimal scheme are given,which provides the theoretical basis for the application of direction finding cross location algorithm.

    Application of Cooperative Communication Technology in Satellite System
    ZHAO Hualong,ZHANG Zhili,WANG Linan
    . 2014, 27(8):  90. 
    Abstract ( 767 )   PDF (726KB) ( 689 )  
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    In light of wide range signal changes in the mobile satellite channel,the cooperative communication technology is introduced into the satellite communication to obtain better anti-fading performance and higher diversity gain.The paper proposes the models of the cooperation between satellites and the models of the cooperation between users.The system bit error rate performance when cooperation occurs between satellites is simulated,which shows that the proposed cooperation scheme decreases the bit error rate and the system performance is improved obviously.

    Parameters Estimate and Separation of Multi-component LFM Signal in QPF
    QU Wenyue
    . 2014, 27(8):  94. 
    Abstract ( 675 )   PDF (631KB) ( 432 )  
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    Quadratic phase function applies estimate of instant frequency to LFM signal.This paper analyses multi-component LFM signal,adopts IQPF to solve the cross terms problem,and uses Clean method for the separation of different strength LFM signals and its parameters estimate,which inhibits the sheltering and interference of strong component signal to weak.The simulation shows that this method is effective.

    Research on 3D Location with Phase Variation
    ZHANG Haipeng
    . 2014, 27(8):  97. 
    Abstract ( 764 )   PDF (1094KB) ( 564 )  
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    The traditional method of passive location takes long positioning time and has low positioning accuracy.A phase change rate based on three-dimensional positioning method is proposed to achieve a radiation source positioning,high positioning accuracy,positioning speed by obtaining phase change rate using the three-element antenna array.The relationship between the positioning error and measurement error is analyzed,and the positioning error expressions are given.A simulation analysis is made of the effect of the phase measurement error and the rate of change of phase measurement errors on the accuracy of the simulation results.The results show that the rate of change of phase errors has the greatest impact on positioning accuracy,thus the primary restricting factor in accuracy improvement.

    A Design and Implementation of a BD Positioning System Based on the Dual Antenna
    XI Zhihong,GENG Gengfei,FU Cunli
    . 2014, 27(8):  101. 
    Abstract ( 850 )   PDF (696KB) ( 664 )  
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    It is concluded from extensive practical BD module statistical analysis that the orientation error of BD positioning error distribution of the module is normal distribution.According to the rule of BD positioning error distribution of the module,the double antenna on the same piece of circuit board module is used to receive the BD positioning signal.The location information provided by the BD module is sent to TMS320F28335 DSP chip for real-time algorithm processing,and the processed information is sent to the embedded ARM chips,which update location information on the TFT LCD screen,and set the BD module working mode according to the user settings.In failure in obtaining the BD positioning information,the DSP sends predicted location information by particle filter algorithm to the ARM chips,and marks as "predicted information" to be displayed on the TFT LCD screen.

    Research into Adaptive Controller Based on NiosⅡ
    ZHANG Lixia,YANG Renhuai,TANG Ze
    . 2014, 27(8):  105. 
    Abstract ( 925 )   PDF (1045KB) ( 586 )  
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    A single intersection adaptive control system is designed using the SOPC scheme to improve the road intersection capacity.The hardware of the controller is designed using FPGA chip with NiosⅡ,and the signal timing optimization model is established with the genetic algorithm in hardware written in VHDL language and of single point adaptive controller procedure by genetic algorithm in C language.The Wenjiang district intersection data of Chengdu city is simulated as an example of the software and hardware system debugging,and an optimization scheme is obtained for the signal intersection.The simulation results show that for intersection signal by using the optimized scheme,the imported vehicle queue is zero.The design of NiosⅡ single point online based adaptive controller proves feasible and effective.

    Study of the Effective Breakdown of Cable Fault Location
    司丰,王菌,罗云鹏,赵继超,张方佩SI Feng,WANG Jun,LUO Yunpeng,ZHAO Jichao,ZHANG Fangpei
    . 2014, 27(8):  109. 
    Abstract ( 652 )   PDF (543KB) ( 622 )  
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    Underground cable faults often happen.In detecting the fault,especially for high resistance fault and open circuit fault detection,the high energy signals are usually used to puncture the fault point.However,it is difficult to judge whether the breakdown is effective or not.This paper firstly introduces the high energy signal generation,and then analyses the effective breakdown for coaxial cable and 10KV high voltage cable on the fault point.The breakdown voltage and the energy necessary of effective puncturing the cable fault point are obtained by calculation and tests.The results are verified by an engineering example.

    Application of Pre-emphasis in High Speed Circuit Board
    LI Dianlai,GONG Xin,WANG Zhijun
    . 2014, 27(8):  112. 
    Abstract ( 667 )   PDF (698KB) ( 654 )  
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    This paper introduces the theory of pre-emphasis technique,and analyzes the attenuation of signal transmitting on high speed circuit board,uses pre-emphasis technique to preprocess the signal,enhances the high frequency part of the signal,and improves the signal transmitting quality.By observing the waveform and the eye diagram of the received signal,the proper pre-emphasis coefficient k=1.3 is confirmed with a pre-emphasis intensity of 30%.The circuit simulation is verified and accomplished in ADS environment,which applies the co-simulation of DSP and Analog/RF.The results show that the waveform rising edge of the signal passing through the transmission medium is improved,and the eye diagram height is significantly increased.

    Design of Illumination Mode and Control Circuit AOI in Inspection System
    HE Chunhong,REN Bin
    . 2014, 27(8):  115. 
    Abstract ( 827 )   PDF (1099KB) ( 739 )  
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    A light source control circuit and secondary illumination system is designed in light the defects in the different illumination conditions.This system adopts corresponding illumination for various objects to detect the best picture quality.Both manual and automatic controls are available to adjust the brightness of the light source in different environments,with separated adjustment for highlighting the defective part of a focused region,thus meeting the requirements of AOI image capture detection of various components.

    Modular Design of Stress Monitoring Fiber Optic Component
    LIU Wenli,LU Zhaohui,GAO Jin
    . 2014, 27(8):  121. 
    Abstract ( 724 )   PDF (730KB) ( 740 )  
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    A modular multi-channel strain signal acquisition system is designed for large quantities of resistive strain gauge data acquisition and transmission in aircraft intensity monitoring.The entire system composed of three modules cascaded together can simultaneously capture 4096 strain signals.CPLD is used to achieve the 4096 analog signal multiplexing and data encoding and decoding,and data are transmitted to the remote using optical transmission technology.The design is suitable for all applications (120 Ω) signal acquisition using resistive strain gages.

    Application of STM32F101VB Microprocessor in the Gas Chromatograph
    YANG Shengfeng,LIANG Yuehua
    . 2014, 27(8):  125. 
    Abstract ( 895 )   PDF (498KB) ( 624 )  
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    The traditional gas chromatograph peripheral interface circuits are not universal and the microcontroller core of the old gas chromatograph can not meet multidimensional data processing of large patterns requirements.A gas chromatograph control circuitry based on STM32F101VB microprocessor is proposed.The microprocessor,with high performance ARM Cortex-M3 32 bit RISC kernel and enhanced I/O port and APB bus,is applicable to new control core of the gas chromatograph.This design meets the requirements of common interface and multidimensional data processing of modern gas chromatography.

    Engineering of a Channelized Frequency Measurement Receiver
    XUE Mingjun,ZHANG Hongmei
    . 2014, 27(8):  131. 
    Abstract ( 622 )   PDF (726KB) ( 666 )  
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    The Ku RF signal is changed to 1.25~1.75 GHz IF signal by down-converter and divided into 26-channel signal by splitter.Each channel signal is followed by filter and power detector.When the RF frequency falls into a channel filter,the channel detector outputs detector voltage which is compared with neighboring channel detector voltage and absolute voltage,then outputs the results to FPGA.FPGA generates frequency codes,simultaneous signals and ready indication by estimating and coding.

    A PWM/PFM AC-DC Switching Power Supply with Digital Control
    ZHANG Qinyang,YANG Chan,LUO Qingfeng,GUAN Jinzhou
    . 2014, 27(8):  135. 
    Abstract ( 641 )   PDF (599KB) ( 718 )  
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    A novel digital control using primary feedback flyback switching power supply is designed by digital control methods,combined with a pulse frequency modulation (PFM) and pulse width modulation (PWM) features.The novel digital control technology can achieve fast dynamic response,tight output regulation,as well as a variety of PWM/PFM hybrid control.Cyclone 3 Series FPGA is used as a digital controller to verify the results,which achieve the desired design requirements.

    Beamforming for Broadband Constant Beamwidth in Worst-case Environment
    LIAO Yanping,SHANG Fei
    . 2014, 27(8):  138. 
    Abstract ( 751 )   PDF (655KB) ( 856 )  
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    Beamforming for broadband constant beamwidth can achieve constant main lobe width in the bandwidth of broadband signal.In traditional tapped delay-line array (TDL),constant beamwidth beamforming can be designed as a convex optimization method.It can be extended to broadband beamforming system with sensor delay-lines.In this paper,a constant beamwidth beamforming is proposed based on SRV constraint in steering vector mismatching of worst-case environment.Matlab simulation validates the effectiveness of the algorithm.

    IPSec Protocol Analysis
    GENG Hang
    . 2014, 27(8):  142. 
    Abstract ( 620 )   PDF (636KB) ( 634 )  
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    IPSec is a suits of security protocol which provide IP layer security,and it get more and more attention with develop of IP network,used in the 4th generation wireless communication and IPv6.This paper deals with the process of IPSec protocol,security architecture,and finally analyses some flaw including AH and ESP protocol,and then find a reasonable solution for IPSec through NAT.

    Research on and Implementation of Far Field Speech Signal Denoising Algorithm
    TANG Junhua,WANG Yonggang,LIU Shihui
    . 2014, 27(8):  144. 
    Abstract ( 845 )   PDF (679KB) ( 509 )  
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    This article analyzes the characteristic of the far field speech signals,summarizes the existing methods to improve speech signals,and presents an improved spectral subtraction algorithm to address the problem that far filed speech signals are liable to be polluted by noise.Simulation and experimental results proves that the proposed algorithm is effective in speech signal denoising,and able to restrain the musical noise and enhance intelligibility.

    An Efficient Algorithm for Acquisition Based on the Differential Digital Matched Filter
    ZHANG Liyin
    . 2014, 27(8):  147. 
    Abstract ( 674 )   PDF (673KB) ( 503 )  
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    Frequency acquisition is an important indicator of system performance of the spread spectrum receiver.Much more captured time and additional resources are required when the received signal that is a combination of several signals.The paper introduces the application of the differential digital matched filter in the spread spectrum communication systems.A multipurpose receiver architecture for acquisition based on the differential digital matched filter is proposed.A two-dimensional search method for Doppler frequency and code phase is converted into one-dimensional search approach for Doppler frequency.The correlation structure in the spread spectrum communication systems is developed,which proves much superior in saving resources and improving efficiency to conventional ones.

    Determination of Cooperative Engagement Capability ADC Quantization Thresholds
    REN Kangkang
    . 2014, 27(8):  151. 
    Abstract ( 645 )   PDF (497KB) ( 478 )  
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    The study of optimal quantization threshold aims to reduce the error caused by the procedure of quantization and to get more accurate results of digital signal process when the valid sampling bit number is fixed in the system of synergy fight.This paper takes the system of synergy fight used to detect the target location as an example to build up the actual signal transformed from the target to the different sensors.Making sure that every quantization data has the same probability to match for the unknown analog signal is the optimal quantization norm.Sensors process the signal by the quantization method,and the probability formula for calculating the quantization thresholds is obtained by formula deduction.

    Research on GPS Signal Capturing
    WANG Bing
    . 2014, 27(8):  154. 
    Abstract ( 699 )   PDF (618KB) ( 564 )  
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    The compatible development trend with the coexistence of multiple systems requires additional performances of the receiver.The software receiver will take the place of the hardware receiver using ASIC and become the direction of the receiver development with its convenience and flexibility.GPS signal capturing based on software GPS receiver is investigated.The Double Dwell Sliding Correlation Method is used to capture the satellite data in the MATLAB.The simulation results prove the correctness and effectiveness of this acquisition algorithm.

    Application of a Recursive Algorithm with Derivative Constraints in High Dynamic GPS Anti-jamming
    WANG Pei,CHEN Jianchun,JIANG Ning
    . 2014, 27(8):  157. 
    Abstract ( 652 )   PDF (514KB) ( 384 )  
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    A recursive adaptive interference suppression algorithm is proposed for high dynamic global positioning system receiver.Based on PI (power inversion) approach,this new method adds derivative constraints to the interference direction of arrival (DOA) and derives a derivative recursive algorithm,which achieves wider null in the jamming direction and higher speed than traditional navigation interference suppression algorithms.

    Multi-channel Fuzzy ART Signal Sorting Algorithms
    HU Min,DENG Huming,HUANG Bo
    . 2014, 27(8):  160. 
    Abstract ( 733 )   PDF (797KB) ( 524 )  
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    New radars of different systems lead to ever more complex electromagnetic environment,making the process of radar signals more difficult.The algorithm based on statistics of histogram used nowadays can not satisfy the requirements.In this paper,Fuzzy ART is introduced into multi-channel signal sorting.Simulation shows the feasibility of this algorithm.

    Parallel Mission Record Data Compression Algorithm Based on Multi-core Processor
    XU Jin,HU Zelin,YANG Zhi,WANG Ying
    . 2014, 27(8):  164. 
    Abstract ( 707 )   PDF (683KB) ( 535 )  
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    Data record and replay is one of the most important modules in mission electronic system.In the procedure of mission execution,real-time data are recorded for later replay and analysis.The size of recorded data increases sharply with the rapid development of sensor performance.The zlib library is used to compress real-time data to overcome the bottleneck of data record performance in speed,and a parallel data compression algorithm on multi-core processor is proposed,which makes full use of multi-core processor to implement multithreaded parallel computing power compression.Experimental data show that encouraging speedup and compression ratio are achieved by using parallelization.

    Algorithm for Water Cleaning Machine Area Calculation
    YAN Xiaokun
    . 2014, 27(8):  167. 
    Abstract ( 617 )   PDF (670KB) ( 447 )  
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    This paper proposed a practical and efficient area calculation methods based on studies of water-based cleaning machine design.The working principle and the feasibility of water cleaning machine are discussed.The mathematical modeling and analysis of area calculation methods are made,which proves its feasibility and practicality.

    Research Based on Immune Clonal Selection Algorithm for Image Compression
    GONG Xiaolei,GONG Tao,PENG Yangqin
    . 2014, 27(8):  170. 
    Abstract ( 702 )   PDF (878KB) ( 365 )  
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    Aiming at the contradictions between compression quality and compression time in the process of image compression,this paper puts forward a kind of image compression algorithm based on immune clonal selection.The algorithm combines the immune clone algorithm antibody diversity,global optimization features and wavelet multi-resolution analysis features.In the compression process not only uses a wavelet decomposition of the low-frequency component,and also joined with a certain frequency portion of the compressed image signal to noise ratio lower,thus ensuring the quality of the image.The experimental results show that,the proposed image compression method has higher compression ratio and good compression effect.

    Improved Sparsity Adaptive Reconstruction Algorithm for Compressed Sensing
    WU Yue,CHEN Bing,QIAN Hongyan
    . 2014, 27(8):  173. 
    Abstract ( 786 )   PDF (1014KB) ( 514 )  
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    For the performance optimization of the greedy matching pursuit algorithm,the linear variable step forward-backward pursuit algorithm (LvsFBP) is proposed based on FBP,a two-stage sparsity adaptive greedy algorithm.LvsFBP adjusts the iteration step size adaptively which reduces operational costs while enhancing algorithm reconstruction accuracy.The simulation results show that LvsFBP offers the better performance of signal reconstruction.

    Instantaneous Darget Using Circuit of Infrared Detection
    ZHENG Guoping
    . 2014, 27(8):  177. 
    Abstract ( 646 )   PDF (788KB) ( 375 )  
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    In the range test,it often needs a projectile moment as the start time reference signal.The infrared spectral characteristic of the flare signal is analyzed in this paper,and the InSb infrared detector is used to design the muzzle triggering system.With indium antimonite device for transient target infrared signal by photoelectric conversion,the dark resistance matching method is adopted to improve the detection sensitivity of the system.Difference threshold processing method is put forward in this paper,and the weak target signals under strong background luminance brightness system can be detected accurately.Through the range test,in the range of 50 m,the timing precision of the detection system developed at 1 μs.

    Development and Application of Ultraviolet Communication Technology
    LIU Xiaoguang,WU Zhongliang
    . 2014, 27(8):  181. 
    Abstract ( 711 )   PDF (1011KB) ( 687 )  
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    A new type optical communication system,the ultraviolet communication system has the potential advantages of good security,powerful anti-jamming,non-line of sight (NLOS) and Omni-directional capability.Difficult to be detected and intercepted,the system can be used in various close-jamming military communications environments.This paper summarizes the latest ultraviolet communications developments and briefly describes the possible applications of ultraviolet communications in army,navy and air force.

    Study of General Aircraft Airworthiness Certificationprocess Equipment and Method
    QIAO Weihua
    . 2014, 27(8):  186. 
    Abstract ( 664 )   PDF (673KB) ( 606 )  
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    According to the examination of civil aircraft airborne equipment airworthinessrequirements,development process combining the seagull 300 aircraft avionic system combined with the airworthiness certification,discusses in detail the process and methods of general aircraft airborne equipment airworthiness certification.Airworthiness certification process is introduced in the paper,which is based,and examine and approve the plan and in accordance with the main contents of verification stage,especially the design and compliance verification manufacturing compliance verification method,has certain universality,the general method can be used as a Chinese general aircraft airborne equipment airworthiness certification.

    Design of High-speed and High-precision Data Acquisition system Based on ARM and CPLD
    Liu Xing
    . 2014, 27(8):  190. 
    Abstract ( 546 )   PDF (762KB) ( 616 )  
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    Based on FIFO+CPLD, a type of data acquisition system with high-speed and high-precision was designed in this paper. The system used an ARM9 processor S3C2440 as controller and combed ADC ADS7891, FIFO buffer memory chip IDT7205 and CPLD, The CPLD realized the precise timing control logic and the FIFO buffer completed the data transmission between A/D and ARM.

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