Table of Content

25 January 2016, Volume 44 Issue 1

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Electronics, Communication & Automation Technology

Multi-Reference Frames-Based Optimal Multi-Hypothesis Prediction Algorithm for Compressed Video Sensing

YANG Chun-ling OU Wei-feng

2016, 44(1):  1-8.  doi:10.3969/j.issn.1000-565X.2016.01.001

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The existing multi-hypothesis prediction methods for compressed video sensing ( CVS) select all possible blocks within the search space of reference frames as the hypotheses,which causes a high computation load in solving linear weighting coefficients and impairs prediction accuracy.To address this issue,a multi-reference framesbased optimal multi-hypothesis prediction algorithm for CVS reconstruction is proposed in this paper.In the algorithm,first,those search blocks which have the smallest sum of absolute differences ( SAD) from current block in measurement domain are selected from multi-reference frames as the optimal hypotheses of current block.Then,the hypotheses are weighted both linearly and adaptively to fully excavate the temporal correlation between video frames.Thus,the prediction accuracy is improved and the computation load in solving linear weighting coefficients is reduced.Finally,the compressed sensing measurements are quantized through the frame-based DPCM quantization to improve video compression efficiency and rate-distortion performance.Simulation results show that,in comparison with the existing CVS reconstruction algorithms,the proposed algorithm achieves higher video reconstruction quality.

Control Strategy and Dynamic Simulation of Two-Wheeled Self-Balancing Vehicle

JIANG Li-biao HE Jia-shou

2016, 44(1):  9-15.  doi:10.3969/j.issn.1000-565X.2016.01.002

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Aiming at the problems of the self-balancing control and steering control of two-wheeled self-balancing vehicles,an active disturbance rejection control ( ADRC) strategy on the basis of the adaptive differential evolution ( ADE) algorithm and an improved proportion-integral-derivative ( PID) control strategy are proposed.Firstly,on the basis of the nonholonomic dynamic Routh equation in generalized coordinates,a nonlinear mathematical model of two-wheeled self-balancing vehicles is constructed by using the Lagrange formula.Then,an ADRC strategy whose parameters are adjusted by means of the ADE algorithm is designed for the self-balancing control,and a PID control strategy combining tracking differentiator ( TD) is designed for the steering control.Finally,a dynamic model of the whole vehicle is constructed through the Adams software by applying the virtual prototype technology,and a co-simulation is performed by combining the Matlab /Simulink control strategy model.The results show that the proposed control strategies can effectively keep the gesture control with a high adjusting speed,a high control precision and a strong capacity of resisting disturbance.

A Distributed Detection Algorithm Based on Local Soft Decision

GUO Li-li GAO Fei SUN Zhi-guo

2016, 44(1):  16-21.  doi:10.3969/j.issn.1000-565X.2016.01.003

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In order to reduce the size of transmitted data on the premise of retaining a certain detection performance,a distributed detection algorithm is proposed on the basis of local soft decision.Then,an optimization problem on the basis of the distributed detection with local soft decision is derived and formulated,and a local soft decision scheme for achieving the optimum detection performance is obtained by utilizing the routine method to solve the optimization problem.Finally,the detection performance of the proposed algorithm is verified by a simulation and is compared with that of the algorithm with uniform quantization or without quantization in the ideal /imperfect channels.Numerical results demonstrate that,in terms of detection performance,the proposed algorithm outperforms the algorithm with uniform quantization,and is very close to the algorithm without quantization when a 3-bit quantization is conducted.

Multi-Frequency Transmitting Beamforming Algorithm Based on Cross Array

LIU Xue-song ZHOU Fan ZHOU Hong TIAN Xiang JIANG Rong-xin CHEN Yao-wu

2016, 44(1):  22-29.  doi:10.3969/j.issn.1000-565X.2016.01.004

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In order to solve the problems of the huge hardware cost and computational load in underwater 3D acoustic imaging system,which is caused by the large number of elements in a receiving planar array,a multi-frequency transmitting beamforming algorithm is proposed for the real-time 3D acoustic imaging on the basis of cross array.In the algorithm,first,transmitting steering directions are subdivided into several sectors.In each sector,a series of fan-shaped beams with different frequencies are transmitted sequentially,and each beam is steered to a specific direction.Then,the number of transmissions is reduced from the number of beams to the number of sectors,thus shortening the scanning time.Simulation results and the analysis of computational load show that the proposed algorithm can obtain the same performance as the direct beamforming method on the basis of the receiving planar array and dramatically reduce both the transducer number and the computational load.Real underwater experiments demonstrate that the proposed algorithm can meet the real-time requirement in underwater 3D acoustic imaging applications.

A Unified Channel Potential Model for Asymetrical Dual Gate a-Si: H Thin Film Transistors

QIN Jian YAO Ruo-he

2016, 44(1):  30-36,43.  doi:10.3969/j.issn.1000-565X.2016.01.005

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On the basis of the Gauss's law,two sets of implicit potential equations describing the changes of surface potential and back one with gate voltage are established for asymmetrical dual gate a-Si: TFT thin film transistors.Then,a unified channel potential model with two independent gates is constructed by solving 1-D Poisson equations.This model can be simplified to a symmetric dual gate model under given conditions.In addition,most of relevant parameters can be physically extracted from real experimental data and only few fitting parameters are involved.On this basis,a novel scheme for the approximation of surface potentials is proposed by means of mathematical transformation and by using the Lambert W function.Numerical results show that the proposed scheme is of better convergence and the approximation of those potentials can be directly used to set the initial values of simulation tools,which effectively improves the computation efficiency of self-consistent solutions to the constructed model.

Design of Anti-Interference High-Linearity RF Front-End

CHEN Zhi-jian CAI Min

2016, 44(1):  37-43.  doi:10.3969/j.issn.1000-565X.2016.01.006

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In order to suppress interferences and improve the linearity of circuits,a SAW-less RF front-end system is designed by using a 0.13 μm RF CMOS process.This design adopts a novel variable-gain low-noise transconductance amplifier with a loop eliminating interferences,a 25% duty-cycle current-commutating passive mixer and a transimpedance amplifier,so as to achieve an RF front-end system of anti-interference,low noise and high linearity.Tapeout and test results show that the designed front-end system accomplishes the goals of 20 dB out-band interference rejection,44.98 dB gain and 2.03 dB noise figure at 2.4GHz with a － 7 dBm 3rd input intermodulation point ( IIP3) and a + 72 dBm 2nd input intermodulation point ( IIP2) being obtained,which means that the designed system needs no surface acoustic wave filter and is of anti-interference characteristic.In addition,the designed system has a power supply voltage of 1.2 V and a power consumption of 36mA.

Fully-Printed Chipless RFID Tags Based on I-Shaped Slot Resonator

MA Zhong-hua YANG Jian-hong

2016, 44(1):  44-49,57.  doi:10.3969/j.issn.1000-565X.2016.01.007

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In order to decrease the cost of RFID ( Radio Frequency Identification Devices) tags,a printable compact chipless tag on the basis of I-shaped slot resonators is proposed.By adding or removing the I-shaped slots of different length and width on conductive materials to perform information coding,different coded tags are obtained.Then,tag information is acquired from the radar cross-section ( RCS) of tags.Finally,the chipless tags of twelvebit code capacity are achieved on a 37.0 mm × 20.5 mm F4BM-1 /2 substrate.Simulation and experimental results demonstrate that ( 1) every slot resonator has its corresponding resonant frequency; ( 2) adjusting the length of slots can change the resonant frequency by a large margin,while adjusting the width can change it slightly; and ( 3) decreasing the space of adjacent slots or the width of slots can greatly improve coding capacity.

Design of GIS-Based Digital Lighting System for City Road

DONG Yu-de ZHANG Chang-hao DING Bao-yong LIU Meng-meng QUAN Xun-hua DU Qing-peng

2016, 44(1):  51-57.  doi:10.3969/j.issn.1000-565X.2016.01.008

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Traditional city road lighting system has shortcomings such as a large quantity of energy waste,difficulty in making regulation work and out-dated control method.In order to overcome these shortcomings,a monitoring and control scheme for street lamps on the basis of the geographic information system ( GIS) is proposed,and a communication architecture between lighting terminal equipment is designed on the basis of ZigBee and GPRS networks,so as to automatically acquire the operating parameters of lighting equipment in real-time,implement the energy-saving strategy and realize visual management and hierarchical control.Thus,such problems as data loss caused by the abort or delay of GPRS networks and the slow massive marker loading of map interface,can be solved,and both data transmission efficiency and reliability of system communication can be improved.Test results in an area of Hefei show that the proposed scheme and architecture can operate about 10 000 street lamps smoothly with a response time of only about 1s,and they can save electric energy by 21.44% in comparison with traditional free control.

A Fusion Method of Satellite Remote Sensing Image Based on IHS Transform and Curvelet Transform

XIAO Hua-chao ZHOU Quan ZHENG Xiao-song

2016, 44(1):  58-64.  doi:10.3969/j.issn.1000-565X.2016.01.009

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The fusion of panchromatic images and multi spectral ones is one of the most commonly-used methods to compose high-resolution color remote sensing images.In order to achieve high-quality color images,it is necessary to fuse the high spatial resolution of panchromatic images and preserve the spectral characteristics of multi spectral images.In this paper,a novel fusion method of remote sensing images on the basis of the IHS transform and the Curvelet transform is proposed to improve the quality of fusion images.In the method,first,the RGB multi spectral images are converted into the IHS images.Then,the panchromatic image and the I component refering to spatial resolution are handled through the Curvelet transform,and are fused by means of the standard difference method.Finally,the high-quality color images are achieved through the inverse transforms.Experimnetal results show that the images fused through the proposed method are superior to those through the other methods in terms of entropy,relatively-dimensionless global error and universal image quality index,and are equivalent to those through the wavelet transform and the PCA transform in terms of average gradient and correlation coefficient.Overall,the proposed method has better fusion performance than the other three typical methods.

ISAR Imaging Based on Sparse Chaotic Sequence Measurement Matrices

TAN Xin FENG Xiao-yi WANG Bao-ping CHENG Wei FANG Yang

2016, 44(1):  65-70.  doi:10.3969/j.issn.1000-565X.2016.01.010

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The construction of measurement matrices is one of the core tasks in compressed sensing inverse synthetic aperture radar ( ISAR) imaging.The chaotic sequence measurement matrices are of excellent pseudo-randomness,which can meet the requirements of compressive measurement.As it is difficult to implement the hardware engineering of the chaotic sequence measurement matrices because of the huge number of independent random elements,a construction method of sparse chaotic sequence measurement matrices is proposed in this paper.In the method,the chaotic sequence measurement matrices are optimized,and then setting the zero along the diagonal direction is performed to make the matrix sparse.Finally,the sparse chaotic sequence measurement matrices are used to conduct ISAR imaging experiments in a microwave anechoic chamber.The results show that,in comparison with the Gauss random matrix imaging method,the proposed method achieves an accurate focusing of ISAR imaging and reduces the computational complexity and the hardware implementation difficulty.

Mechanical Engineering

A New Calibration Method for Line-Structured Light Vision Sensor Based on Linear Scale

KUANG Yong-cong CUI Liang-chun

2016, 44(1):  71-77.  doi:10.3969/j.issn.1000-565X.2016.01.011

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In order to realize a simple,rapid and high accuracy calibration of line-structured light vision sensors,a new direct calibration method of line-structured light vision sensors on the basis of linear scale is proposed,and a planar target and an extraction algorithm of feature point are designed.In the method,by achieving the image coordinates of feature points in the known 3-D coordinates,a subpixel index table is established,and direct calibration of system is realized.The results of calibration and measurement experiments demonstrate that the new calibration method is simple to operation and easy to implement,and is of a high accuracy,specifically,its average measurement error is 0.0045mm in Z axis and 0.0130mm in X axis,Overall,the new method can meet the requirements of industrial production and measurement.

A Hierarchical Method of Interaction Hand Gesture for Virtual Assembly

XIONG Wei WANG Qing-hui LI Jing-rong

2016, 44(1):  78-84.  doi:10.3969/j.issn.1000-565X.2016.01.012

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In this paper,by introducing a gesture recognition technology into the human computer interaction in virtual assembly,a hierarchical interaction hand gesture model is proposed to improve the user experience in virtual assembly tasks.According to the characteristics of assembly tasks and interactive modes,a two-level gesture recognition strategy is designed.In the strategy,firstly,interaction hand gestures are preliminarily classified,and the types of the hand gestures are identified on the basis of context-awareness.Next,a gesture semantic is recognized by capturing the motion features of hand.Then,different interaction modes are integrated seamlessly by estimating the functional region of hand workspace,and thus,users' difficulty in recognition is reduced.Experiment results show that the proposed model and recognition method can effectively improve both the human computer interaction efficiency and the user experience in a virtual assembly prototype system.

An Efficient Evaluation Algorithm for NURBS Interpolation

KONG Xiang-hong LI Di JIAO Qing-song

2016, 44(1):  85-92.  doi:10.3969/j.issn.1000-565X.2016.01.013

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In the high-density interpolation of non-uniform rational B-spline ( NURBS) curves,using the piecewise power function method to evaluate the B-spline basis function consumes much less computing time than the traditional de-Boor algorithm.Therefore,on the basis of the characteristic of the NURBS interpolation,an efficient evaluation algorithm for the NURBS interpolation is proposed by drawing on the recursive calculation laws of the de- Boor algorithm.First,the proposed algorithm is used to deduce the explicit equations of the B-spline basis function in each spline parameter knot interval.Then,NURBS interpolation points are evaluated by using explicit equations,and a corresponding NURBS curve interpolator is designed.The results of the milling experiment with complex NURBS curves show that the proposed algorithm can effectively reduce the computing time of the NURBS curve interpolation and can improve the real-time performance of NURBS interpolators.

Internal Force-Coupling Dynamic Suppression Strategy for Redundantly-Actuated Hydraulic Shaking Table

GAO Chang-hong CONG Da-cheng YANG Zhi-dong QU Zhi-yong

2016, 44(1):  93-99.  doi:10.3969/j.issn.1000-565X.2016.01.014

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When the motion range of redundant shaking table is large,adopting the linearization near the zero position to control the degrees of freedom ( DOF) and suppress internal force coupling can result in large motion errors and poor internal force suppressing performance.In order to solve this problem,a kinematics model and a kinetic model are constructed for a redundantly-actuated hydraulic shaking table of two redundant DOFs and large motion range,and the internal force space structure of the shaking table is analyzed.Then,an internal force-coupling dynamic suppression strategy is proposed on the basis of the real-time solution of internal force space basis.In this strategy,the internal force of the shaking table is reduced by real-time acquiring and dynamically suppressing the force of redundant DOF space.Simulation results show that the proposed strategy can reduce the internal force of redundant shaking table effectively.

Angular Calibration Method of Precision Rotating Platform Based on Laser Tracker

BAI Pu-jun XUE Na LIU Song-tao SONG Tao LI Jin-he

2016, 44(1):  100-107.  doi:10.3969/j.issn.1000-565X.2016.01.015

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For large-diameter precision rotating platforms,to adopt traditional methods to implement high-precision angular measurement is difficult.In order to solve this problem,a rotating angle measurement and compensation method for a single degree-of-freedom rotating platform is proposed on the basis of the spatial coordinates obtained by using a laser tracker.First,on the basis of the geometry theorem that a unique circle can be determined by any three non-collinear points,a mapping function between the rotating angle and the spatial coordinates is formulated.Through a comprehensive analysis of the relationship between the measurement error of the laser tracker and the angular error of the rotating platform,a criterion for the selection of measured radius and angle interval is made so as to fully utilize the measurement accuracy of the laser tracker to realize a high-precision measurement of the rotating angle error.Then,the polynomial interpolation method is utilized to obtain the change laws of the rotating angle error with the rotating angle position,and the real-time compensation of the rotating angle error is realized by embedding the fitted error mapping function into the control system and by modifying the output display of grating.Finally,the proposed method is applied in a calibration experiment on a precision rotating platform equipped with circular gratings.The results show that the proposed method can effectively reduce the angular error caused by the assembly error of circular gratings,which decreases from 40″ to 5″.

Design of Hydraulic Hybrid Cutting Transmission System for Drum Shearer

YANG Yang MA Peng-cheng QIN Da-tong CUI Wei-long

2016, 44(1):  108-113,122.  doi:10.3969/j.issn.1000-565X.2016.01.016

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On the basis of the speed regulation principle of differential epicyclic gears,a hydraulic hybrid cutting transmission system for the drum shearer with speed regulation is designed.Then,according to the system composition,the mathematical models of key parts and their speed control methods are constructed respectively.Finally,the dynamic characteristics of hydraulic motor and drum and the cushion property of the designed system are analyzed by using AMESim.The results show that ( 1) the designed system can regulate the speed of drum shearers,which makes the new machine achieve better cutting performance in complex working conditions in comparison with the traditional drum shearer of constant speed; ( 2) the hydraulic motor and drum have high response speed and can accurately track the goal speed; and ( 3) the designed system can cushion the shock caused by mutation loads.

Investigation into Normal Contact Stiffness of Fixed Joint Surface with Three-Dimensional Fractal

LI Xiao-peng WANG Xue YUN Hai-meng GAO Jian-zhuo

2016, 44(1):  114-122.  doi:10.3969/j.issn.1000-565X.2016.01.017

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On the basis of the traditional M-B model,a three-dimensional fractal model of normal contact stiffness of joint surface is constructed by taking into account the elastic-plastic deformation of micro-bulge and by using the modified W-M function which can better describe the actual surface topography of joint surface.Then,the influences of the fractal scale parameters and the fractal dimension on the normal contact stiffness are investigated through the constructed model,and some phenomena are analyzed.The results show that ( 1) the normal stiffness of joint surface increases with the normal load and the material parameters σy /E ,while it decreases with the increase of the fractal scale parameters; ( 2) with the increase of the fractal dimension,the normal stiffness of joint surface increases when 2. 1≤ D ≤2. 6 but it decreases when 2. 6≤ D ≤2. 9; and ( 3) the normal contact stiffness of the constructed three-dimensional fractal model is less than that of the two-dimensional fractal model with the elastic-plastic deformation.

A Numerical Solution Algorithm for Mechanical Models of High-Speed Four-Point Contact Ball Bearings

LU Chun-yu LIU Shao-jun DAI Yu

2016, 44(1):  123-130.  doi:10.3969/j.issn.1000-565X.2016.01.018

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On the basis of the Hertz contact theory,the mechanical models of high-speed four-point contact ball bearings in the cases of high speeds and zero-speed are constructed respectively.In order to solve the problems that the initial values of the constructed mechanical model at high speeds is undeterminable and their convergence is difficult,a numerical solution algorithm for the constructed mechanical model at high speeds is proposed on the basis of the Newton-Raphson theory,and the range of iteration variables and the selection principle of convergence factors are presented.For the purpose of reducing the solving difficulty,the number of unknown variables is reduced by a half through the mathematical transformation of the constructed mechanical model at high speeds.In order to tackle the stuck phenomenon of the program for larger-scale nonlinear equations,the proposed algorithm is optimized and the computational efficiency is improved.Finally,the results of the proposed algorithm are compared with those of Jones’program.It is found that the convergence and convergence rate of the proposed algorithm can be controlled by adjusting the convergence factor.Thus,the proposed algorithm is proved to be correct.

Computer Science & Technology

Multi-Strategy Discrete Harmony Search Algorithm for Solving Traveling Salesman Problem

WANG Yong-zhen CHEN Yan ZHANG Jin-song

2016, 44(1):  131-138.  doi:10.3969/j.issn.1000-565X.2016.01.019

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Proposed in this paper is a multi-strategy discrete harmony search ( MDHS) algorithm for solving traveling salesman problem ( TSP) .In the algorithm,a discrete improvisation is designed by combining a -opt algorithm,and three strategies are employed together to improve its global optimization ability.The teaching-learningbased optimization strategy is adopted to provide a new way of producing new harmonies,so as to improve the quality of harmony memory ( HM) .The elite perturbation strategy is constructed to explore the neighborhoods of the best harmony constantly to perform a fine local search,so that the convergence precision of the proposed algorithm can be increased.The sort-selection-based update strategy is designed to preserve the diversity of HM for the sake of avoiding premature convergence.Experimental results show that MDHS can solve TSP effectively,and it holds an excellent search performance no matter in convergence speed or precision.

Event Detection Scheme Based on Max-Flow /Min-Cut Algorithm

ZHANG Rui-hua CHENG He-you LIANG Yu

2016, 44(1):  139-144.  doi:10.3969/j.issn.1000-565X.2016.01.020

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In this paper,the max-flow /min-cut algorithm is applied to the event detection in wireless sensor networks,and an event detection algorithm ( G-Cut) is proposed for boundary-abrupt events.In the algorithm,firstly,the sensing data of adjacent nodes are transformed into weight values,and thus a flow network is formed.Then,the event boundary is obtained by using the max-flow /min-cut algorithm to cut the flow network.Finally,the event area is determined according to the direction implied in upload information.Simulation results on wildfire events show that the proposed algorithm achieves a high accuracy of event detection with a small computation amount of nodes,and for multi-event regions,it can guarantee the detection accuracy without increasing the computation amount and traffic of nodes.