• Volume 40,Issue 7,2017 Table of Contents
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    • >Research&Design
    • Comparative analysis of lightning protection effect of cable laying on meteorological equipment

      2017, 40(7):1-5.

      Abstract (1304) HTML (0) PDF 1.43 M (1552) Comment (0) Favorites

      Abstract:Meteorological equipment installed in the field to transmission line to provide power for construction convenient transmission cables are used for overhead laying, the overhead cable easy induction lightning pulse, causing rear end equipment is damaged by the impact. In order to study the transmission lines of different laying ways have different lightning protection effect, through the establishment of the equivalent model of distributed capacitance and inductance characteristics analysis of transmission cable, and the cable laying method analysis different distribution parameters change caused by cable distribution parameters, the lightning pulse attenuation, the cable laying underground with lightning protection good effect on the system equipment. The engineering example shows that the effect of the half burying mode of the power supply cable is general, and the effect of the direct buried soil is the best, and the longer the length of the buried, the better the lightning protection effect.

    • Design of liquid level measurement system based on linear CCD

      2017, 40(7):6-10.

      Abstract (1294) HTML (0) PDF 2.16 M (1385) Comment (0) Favorites

      Abstract:Traditional liquid level measurement methods have many defects, such as measurement accuracy is not high, measurement is not continuous, non contact measurement is difficult to achieve. By studying the transparent reagent liquid level online detection method, the paper designs a kind of noncontact photoelectric liquid level detection system,The system mainly uses FPGA as the main controller, FPGA drives linear array CCD for liquid level sensor, CCD receives the light signal ,which is transmitted through the parallel light beam. Under the action of the driving sequence, the optical signal is converted into one dimension image signal which is easy to be processed by the self scanning mode. Then, the image signal is sent to the PC machine for processing. Last, by analyzing the relationship between the actual level and the image edge pixels, so the measurement of liquid level is realized. The experimental prove that the absolute accuracy of the system can reach 10μm, and the measurement resolution is better than 2 μm.

    • Reflectionmeasurement of planar reception antenna array

      2017, 40(7):11-15.

      Abstract (1406) HTML (0) PDF 2.74 M (1469) Comment (0) Favorites

      Abstract:In the microwave wireless energy transmission(MWPT), in mostly, the received microwave energy was transformed into direct circuit(DC) energy by adopting distributed rectification. The maximal incident power on the receiver array antenna units determines the rectifier circuit design. However, the power received by the cell at the edge of the array antenna array is smaller than others, which resulting in a change to the impedance of Rectifier circuit, mismatchingwith array antenna cells also cause a larger reflection. In this paper, theoretically, The reflection of the receiving antenna array edge unit is greater than that of the intermediate unit, caused by the changes of the input power on the receiving antenna units and the mismatch between the planar antenna array and the rectifier circuits are presented. Then a lowprofile (0.05λ2), high directivity (12.5 dBi), high front and rear ratio (27 dB) QuasiYagi antenna were designed as probes. The reflection power distribution and the incident power distribution of the 10×10 planar array antenna is measured, moreover the reflection factor (the reflection factor is defined as the ratio of the reflected power to the incident power reached in the surface of the reception antenna unit) is calculated. The experimental results is consistent with the theoretical analysis, which plays a guiding role in improving the efficiency of receiver in MWPT.

    • Design of servo circuit based on ARM and FPGA

      2017, 40(7):16-19.

      Abstract (1069) HTML (0) PDF 2.44 M (1414) Comment (0) Favorites

      Abstract:According to the requirement of servo control system for valve servo circuit. The author present a new design of circuit to solve the problem which is widely exists in the servo circuit that the structure of circuit is comp licated and the realtime performance is low. The new design is based on the AD698 as the core of Linear Variable Differential Transformer (LVDT) signal process, with ST’s ARM chip STM32F051 and Lattice’s FPGA chip XP2 PQFP208. The function and hardware structure of the controller and software flow has been given. Experimental results show that the design can improve the circuit performance effectively. It has the characteristics of portability, simple construction, high integrity and more realtime. The system can meet the requirement of servo control system for power of driving,the accuracy of measurement ,and stability of it.

    • Research on multi objective scheduling strategy for user power system under smart grid

      2017, 40(7):20-25.

      Abstract (1775) HTML (0) PDF 2.03 M (1230) Comment (0) Favorites

      Abstract:User power system is an extension of the smart grid in the residential side, is one of the smart grid research hotspot. Based on the dynamic electricity price information, combined with the distributed power supply, the ability of the electric vehicle to feed back the electric energy to the grid, the paper analyzes the influence of the electricity load, the time of the electricity, Board and electric vehicle are established, the particle swarm optimization algorithm is used to solve the problem, and the multiobjective operation of the user power system is scheduled and arranged. Without affecting the user′s electric comfort, a method is proposed to minimize the electricity cost as the goal of electricity scheduling strategy. Finally, through the analysis of examples, the results of MATLAB simulation show that the electricity scheduling strategy effectively reduces the electricity cost of 34.6%, which verifies the feasibility and economy of the electricity arrangement strategy, and provides the theoretical guidance for users to use electricity reasonably.

    • Simulation study on super capacitor energy storage system in microgrid

      2017, 40(7):26-30.

      Abstract (1249) HTML (0) PDF 2.24 M (1558) Comment (0) Favorites

      Abstract:As a kind of high power type energy storage device, supercapacitor is an important part of improving the power quality in microgrid. In this paper, the topology, working principle and double closed loop control strategy of double phase DC/DC converter inner voltage loop under double phase shifted pulse are discussed. Finally, the simulation results on Simulink/MATLAB show that the energy storage system can maintain the stability of DC bus voltage and grid side current under the control strategy.

    • Application of perovskite thin film solar cells in domestic photovoltaic power generation system

      2017, 40(7):31-34.

      Abstract (1026) HTML (0) PDF 1.06 M (1191) Comment (0) Favorites

      Abstract:Crystalline silicon cell, which takes a large proportion in the photovoltaic industry, possesses complicated productive process and relatively high manufacturing cost, hence the study of new solar cell technique has been gaining increasing attention. The perovskite material shows excellent photovoltaic property with simple manufacturing process easy access of all the materials needed, thereby has a promising future in the photovoltaic industry. In the paper, we put forward a new assemble technique of perovskite solar cell according to its requirement of stability of the device, and design a household photovoltaic power generation system under the condition that transmission and distribution system are not convenient . The design includes the calculation of accumulator capacity, and the choice of controller and inverter. The performance of the perovskite solar cell device is verified through tests, which also inspires a new thinking for future household photovoltaic power generation system design.

    • Design of broadband four way filter power divider based on substrate integrated waveguide

      2017, 40(7):35-39.

      Abstract (1412) HTML (0) PDF 2.98 M (1544) Comment (0) Favorites

      Abstract:According to the equivalent relation between the substrate integrated waveguide and conventional rectangular waveguide, a compact wideband fourway equal filter power divider is designed based on substrate integrated waveguide(SIW).The design uses coaxial feed in the center. SIWtomicrostrip transitions are used for the output ports with equal amplitude and phase . The fourrow metal holes are used to divide the waveguide into four cavities on average. In the passband,there are three modes (TE101/TE202/TE303) in the cavities, which can realize trimode bandpass. The high order mode(TE202) is suppressed by the perturbation of the inductive hole, and the stop band performance is improved. Measured results of the filter power divider have shown that the bandwidth is more than 2.5 GHz at centre frequency of 10 GHz. The fourway filter power divider has the advantages of small size, simple manufacture, easy integration with other circuits, etc.

    • Control of PMSM with speed sensorless based on MRAS

      2017, 40(7):40-42.

      Abstract (1076) HTML (0) PDF 1.51 M (1803) Comment (0) Favorites

      Abstract:Aiming at identifying motor speed of the permanent magnet synchronous motor in an accurate manner, a method based on variable structure MARS is proposed. The slidingmode observer is designed and the sliding mode variable structure is added by establishing mathematical models of PMSM, using the motor as a reference model, and adopting stator current as an adjustable model. In the MATLAB/Simulink, make an emulation test for the adaptive system of the nosensor controller in PMSM model. Through observation and analysis of the rotator’s actual speed and the estimated speed curve,a conclusion is drawn that this system can accurately estimate rotor speed with static performance.

    • Method of credibility evaluation in simulation system based on DS/AHP and grey cloud

      2017, 40(7):43-47.

      Abstract (1503) HTML (0) PDF 1.88 M (1424) Comment (0) Favorites

      Abstract:Given the subjectivity and uncertainty of the credibility quantification of complex guidance simulation system, an evaluation model of simulation credibility based on DS evidential theory and gray cloud cluster is proposed. Firstly, the experts′ opinions are obtained by AHP, and different opinions are combined by DS to obtain the index weight of higher credibility. Then the gray cloudclustering model is adopted to quantitatively processing the qualitative results as the whitening weight function in grey clustering. The credibility of the simulation system is evaluated by calculating the gray clustering coefficient. Finally, the evaluation of the HILS simulation system is carried out and the results show that the model is feasible and practical. This model provides a new and effective way for the simulation credibility evaluation and comprehensive evaluation.

    • Design and implementation of shipborne TT&C antenna servo control system

      2017, 40(7):48-51.

      Abstract (1162) HTML (0) PDF 2.13 M (1337) Comment (0) Favorites

      Abstract:Servo drive system Large shipbased is the inner ring of TT&C antenna servo system ,which is the key of the servo system design. Starting from the hardware design, Using the idea of four quadrant operation, This paper designed the siliconcontrolled rectifier amplification system. By zero type threephase rectifier circuit in parallel, the servo drive device is reversible, adjustable steady speed system. We solved the thyristor rectification of defects, implements the effective circulation, harmonic suppression by adopting circulation suppression technology.In order to eliminate the gear clearance, we adopt double transmission chain design. Simulation and practice show that the control strategy has excellent control performance, radar tracking stability quickly.

    • State grid microapplication architecture design and realize

      2017, 40(7):52-58.

      Abstract (1526) HTML (0) PDF 2.82 M (2175) Comment (0) Favorites

      Abstract:In order to adapt to State Grid the information system from traditional architecture model to transform "large platform + micro application" architecture, used the current advanced technology and architecture design idea proposed solutions, in view of the problems existing in the traditional architecture, with its own unique advantages, from the functional architecture, technical architecture, running architecture provide a design and resolvent. And actually carried out the deployment and implementation in UAP micro application project, provide an example of application effect. Through test and data analyze, obtain the results, that the micro application architecture is convenient of development, operation, and deployment. As a new thing, micro application in technology and management, there are still many problems and need to improve, these will be the next step in the direction of the work.

    • Yields concealed VHF omnidirectional antenna integrated design

      2017, 40(7):59-63.

      Abstract (1515) HTML (0) PDF 3.19 M (1498) Comment (0) Favorites

      Abstract:This paper studies monopole antenna and analyzes the principle of traditional monopole antenna and the effects of different scenarios on antenna performance. Then on basis of that a monopole antenna with new structure is proposed, which adopts triangular structure and some methods such as thickened radiator and elevated feed point. The new antenna decreases its dimension and widens its working band. Then loaded antenna is used to improve the properties of the antenna further. Then several antennas are simulated and optimized by HFSS software. The best dimensions are achieved by parameter sweep and characteristics such as radiation pattern and gain are analyzed. Then the antenna three different case simulation and analysis, are infinite ground plane, finite ground plane, , adding nails and the lamp, and its parameters to optimize it for best feature. Finally, the simulation results based on the above, a method of complex integrated structure of the tail concealed ultrashort wave antenna design. And conducted a comprehensive simulation to achieve a standing wave in the 100~400 M band is less than 2.75.

    • >Theory and Algorithms
    • Analysis of the verticality and line scale result of scale steel square

      2017, 40(7):64-66.

      Abstract (1758) HTML (0) PDF 1.31 M (1632) Comment (0) Favorites

      Abstract:Scale steel square is simple, basal length measurement equipment. But it is widely used in our lives. In order to ensure the accuracy and consistence of value transmitting, this article introduces the scale steel squares value tracing method, and analyses the verticality and line scale result which contains the analysis of maximum permissible error and uncertainty. The uncertainty is related to the measurement principle, step and method, according to the sequence of mathematics model, variance and transmission coefficient, sensitivity coefficient, measurement uncertainty source analysis, measurement uncertainty calculation, combined and extended measurement uncertainty calculation.

    • Error analysis of SINS alignment in inertial frame based on QUEST attitude determination algorithm

      2017, 40(7):67-70.

      Abstract (1554) HTML (0) PDF 1.41 M (1479) Comment (0) Favorites

      Abstract:The paper analyze and deduced the error of QUEST algorithm and the uniform relationship with traditional TRAID method for SINS alignment in inertial frame in detail. MonteCarlo simulations analyzed the precision of observation scheme with gravity vectors and gravity integration vectors and the precision of different AD algorithms comparatively.Theory analysis and simulation test show that the QUEST algorithm can achieve the higher precision compared with TRAID under equivalent precision observation condition, and the variance of calculation drops to one sixth of the origin,which can give the theory foundation of algorithm application on rocking base alignment.

    • AGV path identification algorithm based on dynamic threshold

      2017, 40(7):71-74.

      Abstract (1530) HTML (0) PDF 2.47 M (1168) Comment (0) Favorites

      Abstract:Aiming at the guidance path recognition technology based on vision guided automatic guided vehicle (AGV) system, it is vulnerable to the influence of light intensity, pavement reflection, shadow and other factors. To solve this problem, a method of image dynamic threshold acquisition based on path prediction is proposed. By identifying the path point, using linear interpolation income function estimates the current path point image region. Within this area find the optimal threshold. According to the thresholds of the image binarization, find out the current region of the guide line, according to the guide line of its own characteristics to determine the threshold is valid. To get to adapt to the current environment of threshold, and according to this threshold to extract the guide wire. Through this method, the path information is collected, identified and processed, so that the AGV can be faster and more stable on the runway.

    • Research on speech enhancement based on spectral subtraction and neural network

      2017, 40(7):75-79.

      Abstract (1756) HTML (0) PDF 3.26 M (1666) Comment (0) Favorites

      Abstract:Background noise is one of the noise sources of communication system, speech enhancement can reduce or eliminate noise interference, and improve speech intelligibility. Speech power spectrum is adopted orthogonal multi window spectrum estimation for smoothing processing, to reduce music noise from spectrum subtraction under the complicated noise environment. The loss of information and estimation have effectively reduced. Using adaptive spectral subtraction coefficient to adjust spectrum gain and floor to control the residual noise, using the optimized IMCRA algorithm for noise update to speech and silence, the enhanced speech signal has acquired by spectral subtraction and waveform reconstruction after the deep neural network trained data. The simulation results show that the noise reduction effect of speech is good, speech intelligibility is well.

    • Design of effectiveness evaluation system for radar detection in marine environment

      2017, 40(7):80-84.

      Abstract (1492) HTML (0) PDF 6.53 M (3364) Comment (0) Favorites

      Abstract:As to the evaluation demonstration problem for radar detection performance in marine environment, the simulation evaluation system is designed and implemented based on the radio propagation models and radar detection performance models, which is researched with the acquisition and processing methods of environment data and selection criteria for different evaluation models. The functions of information processing, environment parameter input, characteristic database query and setting, equipment performance evaluation and operation assistant decision have been designed in this system.The theoretical basis and technical support are supported to the battlefield preparation and right strategic decision of commanders.

    • >Information Technology & Image Processing
    • Adaptive thresholding algorithm for image segmentation in metal plate

      2017, 40(7):85-89.

      Abstract (1307) HTML (0) PDF 2.48 M (1487) Comment (0) Favorites

      Abstract:For the problem of the characteristics of the grey and white granular background image condition on the surface of the plate metals, onedimensional and twodimensional Wellner adaptive threshold algorithm are the first time to be applied to the scene. Based on those two kinds of algorithm, this paper proposes a gaussian weighted adaptive threshold algorithm to solve the problem. Firstly, this algorithm calculates the gaussian weighted distance between pixels in a window to form a weighted distance diagram and then use the ideology of Wellner "centeraround comparison" to calculate binary image directly. Finally, experiments are carried out on images acquired on actual production line. The twodimensional otsu algorithm, uniformity measurement algorithm, onedimensional, twodimensional Wellner adaptive algorithm and the last improved algorithm are compared. Experimental results show that, compared with other algorithms, the algorithm in the end of this paper has obvious advantages in the image segmentation effect.

    • Improved rapid algorithm of image mosaic

      2017, 40(7):90-94.

      Abstract (1559) HTML (0) PDF 7.79 M (1953) Comment (0) Favorites

      Abstract:Image mosaic aims to accomplish a complete image with stitching multiple images which overlap with useful image features.The paper introduces an improved algorithmwhich isto overcome the drawbacks of longtimecostingin feature point matching and high rate of wrong matching pointsbase on SIFT algorithm. In order to improve search efficiency when matching image features,the paper uses BBF (BestBinFirst) search algorithm instead of KDtreealgorithm,because BBF matching method is carried out according to the priorities of SIFT features, which is established based on the significance of subfeature within SIFT; While KDtree matching algorithm is based on space position from nearness to farness. Furthermore, this paper applies modified RANSAC algorithm to purify wrong matched SIFT features by calculating their error probabilities; while the traditional way adopts a threshold to filter out these wrong matched feature points.Comparing test results with the original algorithm in terms of image mosaicking quality on simple texture images and complex texture images, the test results show that the proposed method can improve the accuracy and speed of image stitching.

    • Image classification based on optimized spatial pyramid matching model

      2017, 40(7):95-99.

      Abstract (888) HTML (0) PDF 1.84 M (1552) Comment (0) Favorites

      Abstract:In the image classification based on the spatial pyramid matching model, all the features in the image are treated equally when the histogram of visual words are constructed, without considering the influence factors of the different regions in the image. Obviously, the target area in image is more important than the background area. In order to avoid that the features of the nonimportant area in the image bring interference, this paper proposes an image classification method to optimize the spatial pyramid model. Firstly, a visual dictionary is constructed by using a clustering algorithm combined with a simulated annealing algorithm and a genetic algorithm. Then, a weighted visual word histogram is constructed using the visual attention mechanism. This method also takes the importance of classifying the images in each region of the image into account without losing the global information of the image. Finally, SVM is used to train and classify the representation vectors of images. Experimental results show that the proposed method can improve the accuracy of image classification.

    • Base on gradient histogram energy image algorithm for person identification

      2017, 40(7):100-104.

      Abstract (1164) HTML (0) PDF 2.49 M (1354) Comment (0) Favorites

      Abstract:In GEI, because binarized silhouettes are averaged over full gait sequence, binarized silhouettes can only capture edge information at the boundary of the person. Based on the defects of GEI algorithm, a gradient histogram energy image algorithm for person identification was proposed. the gradient histogram energy image (GHEI) can capture edge information at the boundary of the person, but also captures edges within the person by means of gradient histograms. The process of gradient histogram energy image on the foreground of each frame (FEFGHEI) calculation can be detailed as follows: First, the foregrounds are segmented from each frame. And then, we calculate HOG on the foreground of each frame separately. Finally, the resulting gradient histograms are averaged over full gait cycles. On this basis, according to the idea of gait energy image (GEI) and histograms of oriented gradients (HOG), the four variations of energy images proposed . The proposed five experiments and gait energy image (GEI) were run on the widely used CASIA gait database and carry on the analysis comparison, The proposed methods show significant performance improvements over the current state of the art.

    • Color image segmentation algorithm based on grid search-support vector machine

      2017, 40(7):105-108.

      Abstract (1558) HTML (0) PDF 2.66 M (1154) Comment (0) Favorites

      Abstract:Image segmentation is the key technology of image analysis ,pattern recognition and other fields.In order to reduce the impact of factors such as light to color and enhance the quality of image segmentation,a color image segmentation algorithm base on the Grid SearchSupport Vector Machine(GSSVM) is proposed.Firstly, the RGB and HSI components were extracted from image.Then components combined into the feature space of the sample for the training of SVM.The parameters of the SVM were optimized through the grid search method when training.Finally, aftertraining GSSVM segmented the color image.Experience has shown that the algorithm can find the global optimal solution within the space of the grid. The segmentation accuracy of algorithm can be 95.6%.The segmentation algorithm is with good accuracy and robustness. Also,the segmentation result is more in line with the visual characteristics of human.

    • Application of virtual reality technology in broadcasting and hosting major practice teaching

      2017, 40(7):109-112.

      Abstract (1366) HTML (0) PDF 1.67 M (1348) Comment (0) Favorites

      Abstract:In order to solve the existing problem between broadcast teaching aims and demands professional practice of teaching media ,teaching resources and multimedia equipment investment limited ,practice outline content simple and to host quality requirements with the bottleneck of technology development more and more,to enhance the use of virtual reality technology is used to report the accident case,through the virtual scene reconstruction technology,threedimensional modeling,rendering and other technical means to carry out the scene recovery accident cases,enhanced reports of this kind of telepresence and authenticity,improve the attractiveness of the program and on the spot to play host professional students can accumulate experience.

    • Computer aided exclusion algorithm for areas without probe coupling of automated 3D ultrasound images

      2017, 40(7):113-116.

      Abstract (1341) HTML (0) PDF 1.55 M (1269) Comment (0) Favorites

      Abstract:In automated 3D ultrasound imaging, effective ultrasonic signal can only be acquired if a good contact between the probe and the skin exists. To be able to achieve computeraided exclusion for areas where were uncoupled, a 2D image mask was generated in the coronal plane. Firstly, the average coronal images were obtained by averaging a series of 2D coronal slices which were continuous or intermittent. Secondly, the binary images were obtained by applying bimodal thresholding method on the coronal projection. The masks were obtained by applying morphology image processing method on the binary image, and choosing the best mask as the finally mask image. Finally, pending coronal plane image′s uncoupled areas were excluded by using the mask, and coupled areas were shown by applying pseudocolor processing. It is shown in the results that the proposed method achieves automated exclusion for areas without probe coupling of the automated 3D breast ultrasound (ABUS) data which can effectively avoid invalid operating of uncoupled areas in the subsequent image processing.

    • Laser beam width measurement method based on image processing

      2017, 40(7):117-120.

      Abstract (892) HTML (0) PDF 2.38 M (1458) Comment (0) Favorites

      Abstract:Traditional laser beam width measurement methods usually adopt optical instruments with diffraction, interference and other methods, which are specific constraints in accuracy and speed. In contrast, there are rarely using image processing methods. The laser beam width acquisition method is obtained by laser beam integration model. The intensity distribution function of laser is obtained by Sobel operator and Gaussian filter, and the pixel width is calculated on the xaxis and yaxis by Hough fitting circle integration area. The experimental results show that the image processing algorithm is practical and reliable for measurement of laser beam width, and the measurement effect is intuitive and convenient compared with the traditional measurement methods.

    • Design of oil painting stick detection system based on machine vision

      2017, 40(7):121-125.

      Abstract (1309) HTML (0) PDF 3.07 M (1113) Comment (0) Favorites

      Abstract:The traditional way of oil painting stick packing is artificial.In order to solve the problem of low efficiency and high cost, this paper designs the system based on machine vision. The ARM chip is chosen as coreof the image processing system,under the condition of limited resource and time. The system collects the image through the camera, controls the motor to rotate the oil painting stick, carries on the image matching, completes delivers. The system first locates, selectsthe image and filters to denoise the image. Thenthe system uses the improved histogram matching algorithm of adaptive threshold, and combines the correlation coefficient between the template image and the image to be matched, which effectively reduces the computation and improves the recognition rate of the system. Practice shows that the work of the system is stable, can achieve the effective adjustment of the angle of the oil paintingwith a high matching speed.The recognition rate of thesystem is above 95%.The system can complete the automatic assembly of products.

    • >Communications Technology
    • Private network with 4G network in the application of emergency communication research

      2017, 40(7):126-130.

      Abstract (1256) HTML (0) PDF 2.21 M (1289) Comment (0) Favorites

      Abstract:The rapid emergency communication command scheduling multimedia information are needed for effective decision making, each group together to a unified command and information interaction, between the private network and private network,between the private network and public network, information cannot be effectively communication unify integration and intelligent data analysis. In this paper based on the IP of the private network and public network, satellite communications, WiFi, computer, information fusion PAD, Internet of things, intelligent medical, intelligent transportation, such as communication network integration, multimedia dispatching command center to adapt to the demand of modern emergency communication. Network integration scheme is proposed in this paper, as well as personal mobile terminal and PC upgrade intercom method, analyzes the core technology and key technology of network integration, network integration in the public security of specific illustrate the importance of network integration in the application of development, adhere to the private network using public advantage, and gradually expand the private network coverage, is the development direction of future network integration

    • Research of network flow feature selection based on machine learning

      2017, 40(7):131-136.

      Abstract (765) HTML (0) PDF 1.54 M (1867) Comment (0) Favorites

      Abstract:With the development of Internet technology, it also brings an increasingly complex network security issues. The traditional traffic recognition technology such as port detection and deep packet inspection has been difficult to deal with the current increasingly complex network environment. As the theory of machine learning become mature, it has been successfully applied in many subject areas such as Image or voice recognition and medical fields. Machine learning methods simulate the human cognitive pattern by computers. The target of machine learning is to establish learning model by studying the existing knowledge and use the learning model to class or predict unknown data. In this research, machine learning methods were applied in internet traffic identification. Firstly, we introduced the research status of internet traffic identification and the relevant concepts of machine learning. Secondly, the main work is to research and compare the influence of different feature selection to identification accuracy based on three machine learning classification algorithms. The author proposed an improved feature selection algorithm and verified the effectiveness of this algorithm by experiments.

    • Effect of the ionospheric delay on passive radar using opportunity transmitters

      2017, 40(7):137-140.

      Abstract (913) HTML (0) PDF 2.71 M (1246) Comment (0) Favorites

      Abstract:In this paper the effect of the ionospheric delay on passive radar using opportunity transmitters is addressed. We establish analysis models and methods on the effects of the ionosphere on passive radar using opportunity transmitters. Ionospheric data TEC(total electron contain)for 15 days published by IGS(international GPS service) are used to study the influence of ionospheric delay. Both low Earthorbiting spacecraft and geostationary are considered. Simulation results show that the positioning error caused by ionospheric delay presents the eastward migration, the positioning error of geostationary can up to several meters, and the positioning error of low Earthorbiting spacecraft can up to several meters.

    • Research on the threshold selection of BigBand sparse spectrum sensing algorithm

      2017, 40(7):141-154.

      Abstract (1171) HTML (0) PDF 1.49 M (1020) Comment (0) Favorites

      Abstract:According to the Nyquist sampling theory, it is necessary to have ADCs of capability of GHz sampling speed to sense the spectrumof GHz bandwidth in real time. But this is not possible with the limitations of budget and energy consumption. The BigBand sparse spectrum sensing algorithm, targeting to the sparsity of signals, is capable of sensing 0.9 GHz wide spectrumusing several 50 MHz low speed ADCs. In this paper, the threshold for eliminating out the noise is researched, by using the statistical parameters of noise. A threshold calculating method is proposed, supporting the implements of BigBand algorithm in practices.

    • Fingerprint matching localization with non offline training based on fresnel theory

      2017, 40(7):146-151.

      Abstract (1177) HTML (0) PDF 3.26 M (1030) Comment (0) Favorites

      Abstract:Devicefree localization (DFL) is to estimate the location of object without carrying any electronic device. In allusion to problems such as low reconstruction speed of traditional radio tomographic imaging (RTI), massive store capacity and time complexity of offline training in traditional fingerprint matching (FM) etc., this paper proposed a localization estimation method with non offline training based on the theory of Fresnel. Firstly change of received signal strength (RSS) of links under the Fresnel region will be calculated, then change of RSS will be modified for satisfying some reality constraints, reference fingerprint database will be established. By establishing fingerprint database, capacity of training fingerprint database can be reduced effectively. Error of actual environment will be taken into consideration and correction will be made to weaken the environmental disturbances. Finally Knearest neighborhood algorithm will be applied to the target positioning estimation. The simulation results show that this method not only can ensure the positioning speed while matching, but also can ensure positioning accuracy.

    • >Data Acquisition
    • Analysis of theeffect of channel error on azimuth multichannel SAR

      2017, 40(7):152-156.

      Abstract (1215) HTML (0) PDF 3.05 M (1120) Comment (0) Favorites

      Abstract:The azimuth multichannel SAR, which is based on multichannel sampling and azimuth spectrum reconstruction, breaks through the ambiguity design constraints, and has the capability of wide swath and high resolution at the same time. However, the amplitude and phase inconsistency of the multichannel and the instability of the satellite attitude cause the error, which results in the decrease of the SAR imaging quality. In this paper, the effect of channel error on the quality of azimuth multichannel SAR imaging is studied. Firstly, the multichannel SAR signal model with channel error is analyzed; the channel error compensation process and spectrum reconstruction method are presented; According to the signal error model and spectral reconstruction algorithm is given with simulation data, the influence of different channel errors on the performance of SAR is analyzed in detail, and the results are used to guide the design of multichannel SAR system.

    • Design of the multi type vibration signal acquisition board

      2017, 40(7):157-160.

      Abstract (1044) HTML (0) PDF 2.13 M (1738) Comment (0) Favorites

      Abstract:In the flight test system, some key parts of the original machine vibration signal bandwidth is high, and the types of testing vibration signal of the acceleration sensor, the backend vibration signal sampling device is often only a single type of sensor, acquisition equipment variety, does not have compatibility. For the above problems, this paper designed a suitable for kinds of vibration of sensor signal, high bandwidth, high precision airborne vibration signal acquisition card. Compared with the traditional single type of sensor signal acquisition card, this article is based on the FPGA to control the vibration of the system design parameter acquisition card with multitype input signal, sampling rate can be configured, collecting advantages of higher precision, suitable for use in complex airborne testing system. Through the test, the feasibility and the effectiveness of the design.

    • Design and realization ofdata acquisition system based oncloserange linear CCD

      2017, 40(7):161-164.

      Abstract (1022) HTML (0) PDF 2.36 M (1019) Comment (0) Favorites

      Abstract:It aims to design a high resolution linear CCD data acquisition system based on CPLDfor Kodak′s RGB tricolor linear array CCDKLI14403. The system makes use of Verilog HDL to realize the timing control of functional modules and logic units. Thelinear array CCDKLI14403 is used as the system image sensor and theoutput signals of CCD are processed by the image specific A/D chip. Finally, the realtime transmission of control command and acquisition between upper and lower computer is via the USB2.0 interface. The method not only reduces the difficulty of coordination and control between the modules of the system, but also has the characteristics of accurate driving timing, good antijamming performance, stable output signal and so on. The experiment shows that the system can effectively complete the image signal acquisition with good performance and flexibility and achieve desired results. Meanwhile, it has a certain universality and scientific value.

    • Determination of sampling period on the digital servo control system

      2017, 40(7):165-169.

      Abstract (1065) HTML (0) PDF 1.17 M (1374) Comment (0) Favorites

      Abstract:Sampling period has important influence on the control performance of digital servo control system, and the sampling period is determined by a lot of factors including servo stability, hardware, interfering signal and so on. Shannon sampling theorem is only a guiding principle to choose sampling period. According to the sampling theorem, the higher the sampling frequency of digital control system, the closer of the control effect of the discrete control system to the continuous control system, but in practical applications, if the sampling frequency is too high and the sampling period is too short, it may not be able to perform complex control algorithm and complex rule of the motion control. It may lead to instability of the system because of the addition of zero order retainer during the process of discretization, and it cannot obtain the optimal effects of PID controller if the sampling period is too long or too short, and in order to restrain the interference signal effectively, it ask for different sampling period because of interference signal has different frequency size and it may be a narrowband or a broadband.

    • Anomaly detection based on large data analysis applied to petroleum catalysis

      2017, 40(7):170-172.

      Abstract (1157) HTML (0) PDF 2.12 M (1419) Comment (0) Favorites

      Abstract:The mechanism and model of anomaly detection and diagnosis for the production equipment in petrochemical industry have the defects of strong subjectivity and mismatch with the actual parameters. Based on the practice and summary of anomaly detection and diagnosis technology of the oil chemical production equipment, combined with the current mainstream data analysis technology, realtime analysis of production equipment on the temperature, flow and pressure data, find the hidden data behind the law, make big data sound, timely warning and fault handling, and to make more informed decisions, reduce losses. Through the test of the tower top temperature variation range of a catalytic converter, it is found that the accident is eliminated in the bud state 6 minutes ahead of time. This technology has practical value in engineering, and it is worthy to be popularized in the field of industrial control.

    • Numerical study of SLD icing detection based on backflow characteristics

      2017, 40(7):173-178.

      Abstract (1691) HTML (0) PDF 2.19 M (1012) Comment (0) Favorites

      Abstract:The supercooled large droplet(SLD) icing detection is a hot spot in the field of aircraft icing detection and protection. Through the analysis of the characteristics of large inertia, high temperature and backward flow of SLD, the backflow characteristics detection method of SLD icing is proposed. The finite volume method was used to study the water trajectory, impact characteristics and icing dynamic characteristics of the water droplets, and the icing mechanism was simulated and validated. In order to solve the problem of freezing coefficient, two ice detector configurations are proposed and numerical simulation is carried out. The result shows that there is a big difference between the small water droplet and the SLD in the icing region of the detector. The icing of the SLD can be identified by detecting the icing region on the probe, and this configuration can solve the freezing coefficient problem to a certain extent.

    • >Embedded Technology
    • Brillouin distributed sensing measurement method based on InGaAs/InP single photon detector

      2017, 40(7):179-183.

      Abstract (1092) HTML (0) PDF 2.80 M (1049) Comment (0) Favorites

      Abstract:A brillouin distributed sensing measurement method was demonstrated based on InGaAs/InP single photon detector (SPD). The temperature and strain characteristics of optical fiber could be achieved by analyzing the Brillouin power and spectral shift distribution. Besides, this method could measure different range optical fiber by adjusting the detection cycle of the SPD. At last, Brillouin spectrum of 25 km fiber was measured successfully and the 0.05% change of the fiber caused by strain was identified clearly. This method improved the sensitivity and the range of the Brillouin distributed sensing, further broadening its applications in the aviation industry, geological engineering and other fields.

    • Research on online programming techniques for DSP based on serial communication

      2017, 40(7):184-187.

      Abstract (791) HTML (0) PDF 1.91 M (1374) Comment (0) Favorites

      Abstract:In order to solve the problems of upgrading inconvenience in some DSP embedded systems, this paper proposes a method of onchip Flash programming based on serial communication. This paper describes the basic idea and implementation steps of the online programming methods. Considering the needs of practical projects, it optimizes the timing of receiving upgrade instructions and allocates application backup area in the onchip Flash. With these steps, the reliability and security of the system are improved. Besides, the system′s fault tolerance and selfhealing ability are enhanced. Experiment results show that the method is effective, simple and reliable. Compared with traditional programming method based on JTAG, it can be operated off the simulator, which improves the maintainability of the embedded system.

    • Pocket type human pulse diagnostic instrument based on cloud

      2017, 40(7):188-193.

      Abstract (922) HTML (0) PDF 3.33 M (1215) Comment (0) Favorites

      Abstract:The comprehensive information of pulse wave such as morphology, intensity, rate and rhythm et al. reflects a host of physiological and pathological information of human cardiovascular system. Modern medicine attempts to analysis cardiovascular dynamic parameters through pulse wave while traditional Chinese medicine obtains diagnosis of the various organs of the human body and the health status of the meridian. This system uses scientific method to collect and analyze the pulse wave. PPG (photoplethysmography) has been widely used in the evaluation of hemodynamic parameters for its advantages like noninvasive, cheap, convenient and so on, especially for blood oxygen saturation, blood pressure and cardiac output measurements. While the pulse signal is collected, related professional algorithm will be applied to extract the cardiovascular dynamic parameters. What’s more, traditional Chinese medicine pulsetaking test technique is also introduced to analyze the health condition of the meridian of human body. Finally, the historical data can been saved to local and shared through TCP remotely.

Editor in chief:Prof. Sun Shenghe

Inauguration:1980

ISSN:1002-7300

CN:11-2175/TN

Domestic postal code:2-369

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