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Table of Content

15 February 2016 Volume 29 Issue 2
  
    Articles
    Mutation-based Compact Genetic Algorithm in Pesticide Detection
    MENG Jiao,TONG Guoxiang
    . 2016, 29(2):  1. 
    Abstract ( 500 )   PDF (641KB) ( 377 )  
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    In order to simplify the forecasting model of pesticide detection,and to improve the prediction accuracy of the detection model,this study uses the infrared spectroscopy technology and the mutation-based compact genetic algorithm (mCGA) to achieve the wavelength variable selection,and to a certain extent,reduce the non-information variables and disturbance variables.Wavelength variables are selected to build prediction model with different algorithms.The root mean square average of the prediction obtained is 0.198 by using mCGA,smaller than those by the compact genetic algorithm (CGA) and by the simple genetic algorithm (SGA) which are 0.241 and 0.289,respectively.The results show that the variable selection by means of mCGA can improve the convergence rate and accuracy of the model,and enable the detection of pesticide quickly and efficiently.

    Task Scheduling in Cloud Computing Based on Optimized Multi-objective Cat Swarm Algorithm
    DING Yuewei,DOU Feifei
    . 2016, 29(2):  4. 
    Abstract ( 533 )   PDF (796KB) ( 333 )  
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    Considering the multi-objective conflict problem for job scheduling in cloud computing environment,this paper proposes an optimized multi-objective cat swarm algorithm (MO-CSO) based on cat behavior using the linear mixture ratio selection method to improve the global search and local optimization ability.The algorithm combines the makespan and total cost to propose an adjustable multi-objective integrated utility function,which implements the intelligent dispatching of resources and task.The experimental results show that the optimized MO-CSO not only has high quality,but also are superior in solving speed and scheduling costs to the multi-objective genetic algorithm (MO-GA) and the multi-objective particle swarm optimization (MO-PSO) algorithm.

    A Community Detection Combining Simulated Annealing and Greedy Method
    WANG Fengxue,CHEN Jiaqi
    . 2016, 29(2):  8. 
    Abstract ( 526 )   PDF (678KB) ( 680 )  
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    To promote the accuracy and velocity of detection for the community structure in the network,this paper proposes the new community detection method of simulated annealing and greedy algorithm (SAGA),which combines the simulated annealing algorithm and greedy optimization.This algorithm uses greedy strategy to guide the irregular and blind movement of many single nodes in searching the optimal solution of the simulated annealing algorithm,thus removing many invalid movements and greatly reducing the search time to achieve the global optimal solution.The results show that SAGA has higher execution speed with better search ability to obtain higher modularity than the simulated annealing algorithm,and can be effectively used in certain applications.

    Contourlet Domain Image Watermarking Algorithm Based on Singular Value Decomposition
    ZHU Meng,CHEN Qing
    . 2016, 29(2):  12. 
    Abstract ( 479 )   PDF (810KB) ( 336 )  
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    Wavelet transform can not represent the geometrical structure of the image effectively and sparsely because of the lack of direction.A digital watermarking algorithm based on singular value decomposition in Contourlet domain is proposed to combine the advantages of Contourlet transform and SVD.After two layers of Contourlet transformation,the host image is decomposed into series of multi-scale and multi direction subbands.The subband of the second layer with the maximum energy is selected to be subdivided into non-overlapping blocks of size 4×4 and then the blocks are decomposed with singular value decomposition (SVD).The watermark information is embedded into the singular value matrix.Experimental results show that the algorithm is simple to implement with good transparency,strong robustness against the common attacks and geometric attacks and is superior to the general algorithms in Wavelet domain.

    Kernelized Fuzzy C-means Clustering Algorithm Based on Features and Spatial Information
    YANG Fei,ZHU Zhixiang
    . 2016, 29(2):  16. 
    Abstract ( 536 )   PDF (1153KB) ( 308 )  
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    When Traditional FCM algorithm processes the noisy images,it exists the poor performance of image denoising,slow clustering,and poor segmentation performance.The nuclear clustering algorithm is combined with the traditional FCM algorithm using the kernel induced distance instead of the new clustering method of Euclidean distance.a modified kernel-based FCM clustering algorithm is deduced by using the spatial information and features of samples.Comparative tests show that this algorithm reduces the time of image segmentation and de-noising by 68% with an improved PSNR by about 10% compared with the traditional FCM algorithm,exhibiting better noise resistance and robustness.

    Impact of Micro-polar Fluids on Journal Bearing-Rotor System
    CAO Xuexiu,SUN Baocang
    . 2016, 29(2):  20. 
    Abstract ( 464 )   PDF (710KB) ( 434 )  
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    The oil-film force of the journal bearing with micro-polar fluid is obtained based on the variational principle.With the rigid Jeffcott rotor as the research object,the nonlinear dynamical behavior of journal bearing-rotor system under different parameters is studied by using numerical integration.The motion morphological of the system is studied by combined bifurcation diagram,Poincare map,time history map and spectral analysis.Numerical results show that there exist many complicated nonlinear dynamics quasi-periodic motion and that micro-polar fluids can effectively improve the stability of the system when bigger Nor smaller L0.

    Simulation and Optimization of Dynamic and Economic Performance for a Pure Electric Commercial Vehicle
    SHI Feifei,LU Xi,LIU Bin
    . 2016, 29(2):  25. 
    Abstract ( 812 )   PDF (1026KB) ( 298 )  
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    A pure electric commercial vehicle under development is studied.The matching of power system is performed through the selection of the motor and the configuration of reducer ratio and the determination of battery packs.The total resistance is calculated through the results of coasting tests for electric vehicle and the vehicle model is established in Cruise.The dynamic and economic performances are simulated and analyzed by inputting related parameters in the model.Results show that the selection of the power system can meet the requirements.

    N-Sample Phase-Shifting Algorithm Based on Linear Phase-Shift Error
    ZHANG Shaodan,LI Lin
    . 2016, 29(2):  30. 
    Abstract ( 457 )   PDF (715KB) ( 773 )  
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    Phase-shift error is always the main source of the measurement precision in phase-shifting interferometry.In this paper,a new phase-shifting interferometry algorithm named  N-sample phase-shifting algorithm is proposed,which can greatly reduce the phase reset error caused by linear phase shifting deviation.Firstly,step phase shifts of phase shifter are estimated.Secondly,the phase distribution of a fringe pattern is calculated by using the obtained phase shifts.Computer simulation shows the proposed algorithm accurately estimates the phase shift and obtains the phase distribution with an accuracy of λ/100,much better than those of existing algorithms.

    An Improved NSGA-II Algorithm Based on Polar Coordinate Transformation
    LIU Jiang,WEI Jingxuan
    . 2016, 29(2):  34. 
    Abstract ( 677 )   PDF (786KB) ( 391 )  
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    In engineering practice,there are many multi-objective optimization problems,to most of which exist infinite multiple optimal solutions that are beyond the capability of traditional mathematical methods such as the gradient descent method and the Newton method if they are non-differentiable or the expression is too complex.The NSGA-II,as the representative of solving multi-objective optimization problem algorithms was put forward,which still has some deficiencies such as mutation operator function is too simple,thus reducing the diversity of Pareto optimal solutions.In order to increase the diversity of Pareto optimal solutions,this paper designs an improved NSGA-II algorithm based on polar coordinates transform that makes Pareto optimal solutions distribution more uniform.The effectiveness of the algorithm is verified by the standard test functions.

    A New Incremental SVM Learning Algorithm Based on KKT Conditions and Hull Vectors
    MAO Yanlei,WEI Yun,JIA Jia
    . 2016, 29(2):  38. 
    Abstract ( 469 )   PDF (792KB) ( 359 )  
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    The traditional support vector machine (SVM) incremental algorithm in the learning process may give up the non-support vectors with implicit information,and requires the training of all the incremental samples.This paper presents a new incremental SVM learning algorithm based on KKT conditions and hull vectors.The algorithm makes use of the characteristics of hull vectors to retrain non-support vectors with implicit information,and it only add the samples violating the KKT conditions to the new training set.The experimental results from Abalone dataset and Balance Scale dataset show this algorithm has better classification effect in the datasets with more columns of properties.

    Study of Self-controlled and Variable Frequency Speed Regulation Control System for Permanent Magnet Synchronous Motor
    XING Kunbo,RONG Jun,CHEN Cunjian,LIAO Zhao,ZHANG Xiaofan
    . 2016, 29(2):  41. 
    Abstract ( 481 )   PDF (794KB) ( 350 )  
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    The control system of separately-controlled and variable frequency for the permanent magnet synchronous motor needs to be measured by the external device,thus increasing the difficulty of the design.A self-controlled and variable frequency speed regulation system for permanent magnet synchronous motor is studied.Self-controlled and variable frequency speed regulation systems can adjust the speed and allow the system to stabilize through position sensor to timely being feedback the speed information when the load is changing.The modeling and simulation of self-controlled and variable frequency speed regulation system for permanent magnet synchronous motor is described in detail based on Matlab/Simulink,and the simulation results are analyzed.The simulation results show that the self-controlled and variable frequency speed self-controlled and variable frequency speed regulation of control system for PMSM has good dynamic and static performance.

    Simulated Road Sign Recognition and its FPGA Implementation
    LI Wei,ZHAI Sheping
    . 2016, 29(2):  45. 
    Abstract ( 553 )   PDF (731KB) ( 379 )  
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    Complex road signs pose hidden dangers to drivers.A simulated road sign recognition system is proposed for FPGA-based auxiliary driving to offer real-time detection and identification of road signs and signals for the driver to respond appropriately.Experimental results show that the hardware circuitry designed using Verilog realizes fast and stable image binarization processing.The system can identify the four signs of Left,Right,No Parking,and No Entry.

    Home Health Monitoring System Based on WiFi
    REN Shengnan
    . 2016, 29(2):  48. 
    Abstract ( 930 )   PDF (1101KB) ( 358 )  
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    A wireless home health monitoring system based on WiFi is designed to provide better medical service.The system uses the WiFi communication solution based on HF-LPB100 for the collection of temperature,heart rate and blood pressure data,which are sent to the server and stored in the WiFi wireless module.Family members and doctors can monitor the physical parameters of the monitored personnel at any time by the smart phone.The realization of the software and the hardware of the system are described in detail.The detailed design and test prove that the practical system has small measurement error and provides doctors with a reliable basis of further treatment.

    Co-word Clustering Analysis Based on PubMed
    MAO Chunli,CAO Chunping
    . 2016, 29(2):  53. 
    Abstract ( 451 )   PDF (859KB) ( 353 )  
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    The co-word matrix in the current co-word clustering analysis can not fully reflect the connection between the keywords.This paper proposes a new method to build co-word matrix based on the high frequency keywords co-occurrence in the same paper with variety of formats.The shortcomings of traditional clustering algorithms,such as poor performance in non-spherical cases and difference in size clusters,are pointed out.The paper proposes an improved CRUE algorithm to cluster the Co-word matrix.The new co-word clustering analysis has been made of lung cancer in PubMed,which proves its feasibility.

    A Vertical Working Embedded System Based on Linear CCD
    CAO Huajie,L Chuanlong,LIU Haodong
    . 2016, 29(2):  58. 
    Abstract ( 494 )   PDF (1066KB) ( 376 )  
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    A two wheeled upright systems for narrow and complex electromagnetic environment is designed with a Freescale xs128 embedded micro-controller as the controlling and processing core.The linear CCD and MMA7260 accelerometer and ENC03 gyroscope are used for road condition detection and Kalman algorithm for filtering.Hardware and software design is performed and the algorithm debugged.The experimental tests show that the system is stable and reliable,and can be applied to this particular scene.

    Defogging Image Restoration Based on Four Order Partial Differential Equation
    LI Guilin,WANG Chuangxin,WAN Zhiyin
    . 2016, 29(2):  62. 
    Abstract ( 540 )   PDF (806KB) ( 319 )  
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    The fog image contrast is reduced with may gray areas.In order to effectively remove the image of the mist and the effect of image in the vision.An image degradation model is built based on the fog image attenuation model and atmospheric optical model.The energy functions are constructed using the scene depth and image gradient,and the energy function minimum calculated using the four order partial differential equation and some known information.The fog image restoration algorithm is achieved with the four order partial differential equation by finite difference numerical method.The experimental results that better image defogging effect.

    Adaptive Image Segmentation Algorithm Based on the Adjacency Matrix
    GONG Kaichun,WU Chunxue
    . 2016, 29(2):  66. 
    Abstract ( 481 )   PDF (859KB) ( 316 )  
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    The image segmentation algorithm based on clustering is a common one.Traditional clustering algorithm requires the determination of the initial cluster centers and cluster number of categories,and how to determine the optimal cluster number of categories is a major challenge.An adaptive image segmentation algorithm based on the adjacency matrix is proposed to overcome the local optimization caused by artificial determination of the initial cluster centers and cluster number of categories by traditional clustering algorithms.The proposed algorithm is compared with the traditional algorithm by experiment and applied to segmentation.Experimental results demonstrate good robustness and stability of the algorithm with more accurate result of clustering for segmentation than those by the traditional algorithm.

    Design of Three-Dimensional Surface Topography Evaluation Software System Based on Matlab GUI
    LIU Min,LI Jun,WANG Haoyuan,HUANG Qiang
    . 2016, 29(2):  70. 
    Abstract ( 502 )   PDF (805KB) ( 320 )  
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    The workpiece surface topography characteristics of industrial production have a strong impact on surface performance and the use of functional components.The paper studies and improves the evaluation method of Gaussian filter to eliminate boundary effects.Software evaluation system is developed using Matlab to realize graphical display of the surface morphology,filtering and evaluation of surface characterization parameters.Related test are performed.The software evaluation results are in good agreement with the calculation results with the system error within 1%.

    Face Recognition Based GPCA of KNN and SVM Fusion
    JIAO Shuhong,SUN Zhishuai
    . 2016, 29(2):  74. 
    Abstract ( 491 )   PDF (610KB) ( 334 )  
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    In view of the poor face recognition rate of the K Nearest neighbor and support vector machine (SVM),a KNN and SVM fusion recognition method is proposed with a Gabor wavelet and principal component analysis (PCA) for face feature extraction and KNN-SVM classification method for face recognition.Experiments based on ORL and YALE face database show that the proposed algorithm offers a recognition rate up to 98.89%,higher than both KNN and SVM.

    Structural Design and Height Optimization of Manned Biped Robot
    GU Yanxiu,HUA Yunsong
    . 2016, 29(2):  77. 
    Abstract ( 362 )   PDF (712KB) ( 347 )  
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    For the problem of wheelchair inconvenience when crossing stairs,steps,ravines and other obstacles,combining with legged robots,this paper proposes the structural design of a new manned biped robot.Just with two degrees of freedom,its control is very simple.In order to get the most comfortable ride height of the human body,take the third derivative of the movement curve of the thigh to get the jerk.Then the optimum height is determined through analysis of the absolute value of the jerk.The simulation results are carried out to verify the motion stability of the robot mechanism by using Matlab.Through multiple test data analysis,the results of the evaluation of the software are consistent with the theoretical values of the mathematical calculation and error rate is less than 1%.

    Design of Temperature System for Multipoint Temperature Measurement and Control Based on C8051F350
    HUANG Dong,SHAN Qiuxia,LI Jianjie
    . 2016, 29(2):  81. 
    Abstract ( 768 )   PDF (717KB) ( 649 )  
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    Traditional equipments obtain the temperature of the current environment by single point measurement,lacking in effective control of the uniformity and stability of system temperature.A drive circuit based on C8051 and IR2110 is proposed.We take advantage of PID algorithm and multiplex measurement to make the driving circuit work independently.The experimental results show that the temperature of different points can be kept at the set temperature in the system with a control precision of within 0.5 ℃ and a temperature uniformity of within 1 ℃.

    ARM9-based Remote Video Monitoring System for Combine Harvester
    CHEN Jin,CHEN Si,WANG Yifan,WANG Zhe
    . 2016, 29(2):  85. 
    Abstract ( 874 )   PDF (835KB) ( 365 )  
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    The ARM9 is taken as the central processor in the system to achieve the remote video monitoring of the granary,threshing drum,cut table and cab of combine harvester.The hardware and software of system are designed and video compression algorithm is improved.A 3G router is used as the transmission equipment in the 3G network.Then the remote video monitoring is achieved by transplanting Linux operating system in the software,downloading camera program and setting the development board as a server.

    SSH-based Security Architecture System Design and Implementation
    WANG Lei,LIU Na,MA Xiaoming
    . 2016, 29(2):  89. 
    Abstract ( 548 )   PDF (628KB) ( 358 )  
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    In order to realize the safety of the zoo and parents with young children shuttle service,this paper proposes a security system based on SSH framework design and implementation of test system design scheme,and complete the hardware and software design.Part of the system hardware is mainly composed of the SSH in Web application development of open source framework,and the software adopts the overall architecture design based on SSH framework.The layered concept is employed to complete the testing of the output signal.Practical application shows that the system has the characteristics of simple operation and accurate test,meeting the design requirements.

    A Shadow Detection Method in High-resolution Remote Sensing Imagery Based on Novel Shadow Index
    SHUAI Tao,ZHANG Hongyan
    . 2016, 29(2):  92. 
    Abstract ( 531 )   PDF (1219KB) ( 332 )  
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    With the improvement of the remote sensing images' resolution,the presence of shadow in High-resolution imagery is much more evident,which will be a serious obstacle for image interpretation.Therefore,the shadow identification is important in image analysis.Shadow areas are easy to be confused with other classes in RGB space,while having lower brightness,higher saturation,and greater hue value.In view of this,this paper proposes a shadow detection method based on a novel shadow index.The shadow index highlights the shadow areas,while suppressing the nonshadow areas.The histogram thresholding segmentation is performed by Ostu algorithm to acquire the shadow detection result.Experimental results demonstrate that the proposed approach can separate shadow from nonshadow effectively.

    Design and Development of NC System Based on Vericut
    YANG Guangze
    . 2016, 29(2):  96. 
    Abstract ( 496 )   PDF (724KB) ( 294 )  
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    The computer NC system of hardware and software are more dedicated and easily appearing the non-compatibility among different manufacturers with different equipments in the current market.This paper proposes the design and development of NC system based on Vericut to meet modern manufacturing with intelligent and network direction development.This software system adopts the PMAC as core movement controller,using Vericut software model to obtain the operation parameters,thus developing an open-CNC software platform of high compatibility in the VS2005 development environment.Experiments show that the software has good potential applications in making up the current incompatible problem of different device operating systems.

    Environmental Information Control System for Small Greenhouse Based on ZigBee
    Qiao Yurong,ZHANG Xing,CHENG Jianyun
    . 2016, 29(2):  99. 
    Abstract ( 510 )   PDF (723KB) ( 329 )  
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    A monitoring system based on wireless sensor networks is proposed to replace the traditional intelligent monitoring system that suffers from complex wiring,relatively high cost,poor accuracy and lack of scalability.The CC2530 chip which integrates the low power consumption and data transceiver is used to design the network nodes.The upper computer software is also designed offering such functions as information display,information management and system operation for monitoring,processing and displaying of the parameters in the greenhouse environment.The results of greenhouse test show that the system has good man-machine interaction,good expansibility and accuracy,simple operation and low cost.

    Selective Laser Sintering Formation of Si3N4
    CAO Chong,SHEN Jingfeng,ZHANG Peizhi,GUO Fangquan,QI Hai
    . 2016, 29(2):  102. 
    Abstract ( 376 )   PDF (944KB) ( 339 )  
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    The forming principles of selective laser sintering using ceramic are described.Silicon nitride (Si3N4) and epoxy resin (EP) are used as raw materials for selective laser sintering by mechanical mixing.The flowability and apparent density are tested and selective laser sintering experiments are conducted.The morphology of sintered parts are observed by scanning electron microscope with its three-point bending strength tested.The results show that the optimization of Si3N4 and EP powder particle size grading can effectively increase the density and strength of sintered parts.When powder particle size is close to single layer thickness,it is easy for sintering parts to move and warp;for a particle size less than 40 μm,it is easy for the powder to stick to the spread powder roller.

    A New Hybrid Cladding Photonic Crystal Fiber with High Birefringence
    ZHANG Xuedian,JIAO Jiajie,YAN Zefan,CHANG Min
    . 2016, 29(2):  105. 
    Abstract ( 447 )   PDF (576KB) ( 331 )  
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    A new hybrid cladding design is proposed for photonic crystal fiber (PCF) with the light-guiding mechanism of total internal reflection.The full vectorial finite-element method (FEM) is adopted to analyze the impact of the structure parameters on birefringence of this fiber.The structure of this fiber is numerically analyzed using the full vectorial finite element software (COMSOL).Simulation show it is capable of a birefringence of the order of 10-2 at a 1.55 μm wavelength based on the choice of the ellipticity parameter η and the air-hole pitch Λ of the fiber.

    Short-time Withstand Capability of Copper Aluminum Composite Bus Bar
    BAI Zhisheng,CHEN Jianbing,XIN Shangzhi
    . 2016, 29(2):  109. 
    Abstract ( 516 )   PDF (576KB) ( 329 )  
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    TLF bus is a new composite conductor material and a good substitute for copper bus bar,which enjoys light weight and low cost of aluminum while maintaining the antioxidant ability of copper busbar surface characteristics.But TLF bus must to validate its short-time withstand capability when used in low voltage complete sets of equipment.The TLF bus short-time withstand capability in low voltage complete sets of equipment and bus duct are studied by theoretical calculation and analysis.Experiments show that TLF bus used in low voltage complete sets of equipment and bus duct meets the requirements of short-time withstand capability by adding insulation brace or change the clip distance L between values,paving the ground for its application in low voltage complete sets of equipment and bus duct.

    CFD Analysis of Fluid Dynamic Characteristics in Electronic Assembly
    QIU Zhongquan,GUO Changning
    . 2016, 29(2):  112. 
    Abstract ( 453 )   PDF (1070KB) ( 315 )  
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    Glue jetting is the key technology in electronic assembly process.The problem is that how the equipment ejects small dot size during microelectronic encapsulation application.A 2D geometrical model is created to present needle and nozzle impact structure based on working theory of pneumatic actuator.CFD computational fluid dynamic characteristic analysis software is used to simulate glue exit velocity from nozzle orifice and to calculate hydraulic pressure inside compressed chamber.The final simulation results demonstrate that needle tip geometry dimensions and needle stroke and nozzle flared angle are the major factors to affect the jetting speed and ultimately determine the bead size.

    Design and Implementation of A Flow Control Mechanism of Rate Adaptive System in Satellite
    YANG Lei,GONG Xianfeng
    . 2016, 29(2):  116. 
    Abstract ( 528 )   PDF (772KB) ( 297 )  
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    A flow control method for rate-adaptive-system in satellite is proposed for the significant increase in signal attenuation in rainy weather with the frequency.Based on the improved token bucket algorithm,this method can guarantee the proper bandwidth of services,by accumulation and comparison of multiple packets.It is shown that the rate-adaptive-system using the method can limit the service occupying excess bandwidth.This method has been implemented in FPGA for its low-complexity and small resource consumption.

    Filter Design Based on Model Correction Technology
    HU Xu,LI Gang
    . 2016, 29(2):  119. 
    Abstract ( 537 )   PDF (598KB) ( 320 )  
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    The paper presents a novel filter design method based on model correction technology to handle the time consuming full wave simulation of the filter.By pre-approved fitting formula,the iterative correction is carried out on the filter structure size,avoiding the time-consuming full-wave simulation optimization.A design example of a 4 coaxial cavity filter is provided.Simulation results are in good agreement with the theory of electromagnetic filter synthesis results,confirming the validity of the proposed method.

    Sliding Mode Control in Bidirectional DC/DC Converter
    JIN Aijuan,ZHAO Qin,LI Shaolong,YUAN Canghu,LI Shuang,MEI Yan
    . 2016, 29(2):  122. 
    Abstract ( 502 )   PDF (663KB) ( 358 )  
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    In terms of the limitations of photovoltaic cell itself,the battery should be needed to assist to load power supply.In this paper,a bidirectional DC/DC converter is proposed mainly for battery charging and discharging system.Then a new type of sliding model controller is designed according to the state space averaging model of bidirectional DC/DC converter.Simulation results and analysis show that the static error is effectively reduced with stable output when the proposed bidirectional DC converter is adopted for the switch tube alternate conduction,thus better system stability and transient.

    〗Adaptive Smart Harmonic Current Detection
    MA Lixin,ZHOU Lei,ZHANG Haibing,LUAN Jian
    . 2016, 29(2):  126. 
    Abstract ( 511 )   PDF (737KB) ( 334 )  
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    The accuracy and real-time performance of APF detecting the harmonic current is vital to improving the quality of electric energy.The method based on NLS (non-linear least squares) and ADALINE is proposed in this paper.NLS is used to estimate the frequency of the network voltage.ANN is used to estimate the initial phase of the network voltage and the amplitude of the network fundamental active current.Through the frequency and the initial phase of the network voltage,the sine signal whose frequency and initial phase is the same as the network voltage is generated.Compared with the traditional method,the time of detecting the phase,frequency,and amplitude of the network fundamental active current is apparently shortened and the accuracy is obviously improved.The method proposed precisely detects the fundamental current in 0.02 s.Simulation shows the effectiveness and superiority of this method.

    An Automotive Buck-boost Type Switching Power Supply Based on LM5175
    ZHOU Pengfei,ZHONG Zaimin
    . 2016, 29(2):  129. 
    Abstract ( 678 )   PDF (965KB) ( 371 )  
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    A four switch Buck-Boost power supply based on TI's power supply chip LM5175 is designed for a motor controller used in a new energy automobile.The input and output voltage range,current range and switching frequency are established according to vehicle-mounted conditions.Reasonable input and output capacitors,inductor,and MOSFETs are selected to build the power supply chip's peripheral circuit.The Bode diagram of the power supply is drawn to analyze the stability.The two experiments performed with the same load and different input voltage and with the same input voltage and different load respectively show that the power supply can work normally with good efficiency.

    A design of class E Power Amplifier based on GaN HEMT
    YAN Jijin,CAI Fei
    . 2016, 29(2):  134. 
    Abstract ( 507 )   PDF (632KB) ( 454 )  
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    Power-Added Efficiency is a very important factor of mobile and wireless communication systems.High efficiency leads to long lasting connection time for mobile,nomadic and wireless devices using battery energy.Especially for public and homeland security applications,long connection time of wireless communication devices is desirable for emergency situations.This paper proposes a high efficiency class E power amplifier based on a Gallium Nitride High Electron Mobility Transistor as a power device.Load-pull technique and parallel load circuit was applied during the design process to determine the optimal load impedance for the maximum Power-Added Efficiency.Measurement results of the fabricated class E power amplifier are provided with Power-Added Efficiency (PAE) of 74% from 120 MHz to 200 MHz while power gain of and output power are about 13 dB and 40 dBm separately.

    Design of Automatic Switching Circuit for Reference Source Based on AD8306
    ZHANG Qingzhong,HU Shijin,SHI Yu
    . 2016, 29(2):  137. 
    Abstract ( 464 )   PDF (724KB) ( 402 )  
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    An automatic switching circuit which measured by logarithmic amplifier detection method to switch reference source based on AD8306 is Introduced.The automatic switching circuit has the advantages of a controllable threshold,a larger dynamic range and a higher accuracy.The circuit test results show that the dynamic range is up to 100 dB and the accuracy is ±0.4 dB,meeting the requirements of engineering applications.

    Linear Array Channel Equalization Based on Direct Sequence Spread Spectrum
    MENG Tao
    . 2016, 29(2):  141. 
    Abstract ( 400 )   PDF (712KB) ( 324 )  
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    In the space multipath channel vertical linear array communication,the error rate is high due to the multi array element code interference results in channel imbalance,thus the need for channel equalization design.By the traditional method,the random code spreading method is used for the communication channel equalization,leading to high nonlinearity distortion and poor balance effect of the spread spectrum signal.A linear array of communication channel equalization algorithm based on direct sequence spread spectrum is proposed using recombinant multiple vertical line array size component received spread spectrum signal after high-level amplification and mixing,and origin of the synchronization of pseudo random sequence of intermediate frequency spread spectrum modulation signal to realize channel equalization.Simulation results show that the vertical line array communication by this algorithm exhibits good channel equalization and code interference suppression performance by effectively reducing the bit error rate and improving the communication quality.

    Hardware Framework Design and Plots Processing Development in Double Redundancy Radar System
    YAN Botao,WAN Weihua
    . 2016, 29(2):  145. 
    Abstract ( 583 )   PDF (649KB) ( 366 )  
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    A universal highly reliable plot processing hardware platform is developed for interaction between track and plot and realizing double redundancy of radar processing hardware with multi-form high-speed interface and powerful processing capability.It can process four-channel radar plot data simultaneously based on the main component of DSP+FPGA,and can fully satisfy multi-channel data exchange by using standard CPCI bus and six pairs of high-speed channel of 5 Gbit·s-1 data transfer rate as main communication interface.A type of double redundancy radar is taken as an example to describe the engineering realization of plot processing on the platform.It is shown that this algorithm is of practical significance in plot processing,interaction between the track and plot,and filtering of plots between frames.

    Industrial Dust Concentration Measurement by Capacitance Method
    LI Jing,SI Jin,WANG Zemin
    . 2016, 29(2):  148. 
    Abstract ( 476 )   PDF (830KB) ( 317 )  
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    The research on the dust concentration measurement is very important to the accuracy and precision of the measure of the dust concentration.The principles of the capacitance sensor are discussed and a new capacitance measurement method is proposed.The measurement circuit and system are designed using the bridge method to measure the industrial dust by experiment.The experimental results are analyzed and calibrated to yield the relationship between the measurement result and the dust concentration.This results show that the capacitance method is reliable in industrial dust concentration measurements.

    WDM Driver Design of High-speed Data Transmission Card Base on PCI-E Bus
    JING Boli,MENG Lilin,ZHANG Yayun
    . 2016, 29(2):  152. 
    Abstract ( 413 )   PDF (771KB) ( 340 )  
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    A high-speed data transmission card device based on the PCI-E bus is designed with the device driver implemented using WDM driver designs in the 64-bit Windows system.The development of WDM driver is introduced in detail,including acquisition of hardware resources,DMA high-speed data transmission,and MSI interrupt.Tests show that the driver with high transmission efficiency and reliability can be applied to high-speed data transmission card device,and that the driver can be transplanted into other similar data transmission devices.

    Gigabit Ethernet Data Transmission Design Based on FPGA
    YUAN Yang,MENG Lilin
    . 2016, 29(2):  156. 
    Abstract ( 479 )   PDF (921KB) ( 358 )  
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    To solve the problem of how to use,using The Altera Cyclone IV series FPGA is adopted as the embedded development platform to implement the TCP/IP protocol using Nios II which is a soft core processor for high speed gigabit Ethernet access.Tests on the designed Gigabit Ethernet transmission scheme indicate that the transmission data can be received and transmitted correctly with a high transmitting efficiency.

    Design of Intelligent Charger for Lithium Battery
    JI Lili,LI Ye,JIANG Zhaolin,ZHANG Weichang
    . 2016, 29(2):  159. 
    Abstract ( 510 )   PDF (687KB) ( 311 )  
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    According to the principle and characteristics of lithium battery,a correct charging mode is proposed.The whole charging process of the lithium battery pack is managed intelligently by the micro controller.The dynamic adjustment of the charging current is implemented by the acquisition of the information of charging current,voltage and temperature in real time in the charging process.This design adopts the intelligent control system and power conversion system as a core,integrating such functions as intelligent alarm,automatic temperature regulation,real-time monitoring,and charging protection.The experiments demonstrate that the charger has a broad market prospect with its safety and reliability.

    Application of Three-phase AC Regulating Voltage Circuit in Soft Start of Asynchronous Motor
    LIU Kai,RONG Jun,SONG Neng,LIU Sheng,ZHANG Lei
    . 2016, 29(2):  163. 
    Abstract ( 442 )   PDF (926KB) ( 302 )  
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    The SCR three-phase AC adjusting voltage circuit is introduced into the soft starting of asynchronous motor to address the motor and load damages because of too large a starting current and starting torque for asynchronous motor with full voltage starting.The paper firstly describes the working principle of the SCR three-phase AC adjusting voltage circuit,and then introduces the application of the soft starting for asynchronous motor.The modeling method of three-phase AC voltage regulation in soft starting process based on Matlab/Simulink is studied in detail for asynchronous motor,and finally the paper gives the simulation results in the soft starting and full voltage starting,and the simulation results are compared and analyzed.The research results show that the problem of starting current and torque is improved significantly by using the soft starter compared with full voltage starting.

    Research on Mobile OA System Based on Hybrid Key Digital Signature Technology
    WANG Shizhi,Ma Zining
    . 2016, 29(2):  167. 
    Abstract ( 400 )   PDF (603KB) ( 272 )  
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    Aiming at the poor efficiency of the traditional RSA algorithm in the mobile OA system,a complete mobile OA system is developed based on the hybrid key digital signature technology.Before using the RSA algorithm,the digital signature is generated by the Hash function,and then the digital signature is performed.Experiments prove that the mixed key digital signature technology greatly improves the efficiency of the digital signature while maintaining the security.

    A Lightweight File Secure Management Scheme for Small and Middle Enterprise
    XIE Hui,WANG Guoqi,LEI Wan,ZHENG Tao
    . 2016, 29(2):  169. 
    Abstract ( 478 )   PDF (790KB) ( 306 )  
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    The development of enterprise informatization brings new challenges to the secure files management,but traditional file security management schemes only pay attention to the file security and ignore the identity authentication for the person who uses the file.Based on identity authentication and file encryption technology,a lightweight file secure management scheme is proposed to meet the demands of file storage protection for small and middle enterprise.The scheme has been proved to be able to offer secure,efficient storage and usage through detailed analyses of security and performance.

    An Android Application Protection Method Based on Data Encryption Technology
    WAN Yi,ZHU Zhixiang,WU Chen,MA Wen
    . 2016, 29(2):  173. 
    Abstract ( 527 )   PDF (808KB) ( 348 )  
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    With the popularity of Android system,the security problem of Android Application is attracting increasing attention.In view of the Android package's easy decompilation,this paper firstly introduces the basic structure of Android package,then studies the Android code protection technology based on 3DES,RSA algorithms and authentication mechanism of the remote server,and finally proposes an Android application protection method based on data encryption technology.The method prevents the code from being destroyed and modified by attackers,and enhances the security of the Android application.

    Reliability of OpenFlow-based SDN
    ZHANG Tuanli,LV Guanghong,YANG Peilin
    . 2016, 29(2):  177. 
    Abstract ( 403 )   PDF (813KB) ( 344 )  
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    SDN is a new type of network framework that separates control plane and forwarding plane and provides network management with programmable interface for easier SDN network management.With the increasing application of OpenFlow-based SDN,its problems have also been revealed among which reliability is of great importance.This paper analyses factors that causing network failure,classifies network failure into controller,link and node failure,and presents solutions concerned.Finally the trend of future study on the reliability of OpenFlow-based SDN is pointed out.

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