Table of Content

15 May 2013 Volume 26 Issue 5

  

Articles

Design and Implement of RSSI Improved Positioning System on Tiny OS Platform

LI Xuelian,QIAO Gangzhu,ZENG Jianchao

. 2013, 26(5):  1. 

Abstract ( 1129 )   PDF (881KB) ( 779 )  

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RSSI improved localization algorithm is an effective localization algorithm in wireless sensor network node localization,which can improve the positioning accuracy.RSSI improved positioning system is designed based on the software platform of NesC language and the hardware platform,which includes the iris node and mib520 interface board provided by Crossbow.Experiments in indoor and outdoor environments proved the validity of the system.

Research and Implementation for Vehicle Rollover Prevention System Based on the MEMS Sensor

ZHANG Haokun,NIE Pengpeng,LIU Minfeng

. 2013, 26(5):  6. 

Abstract ( 1113 )   PDF (551KB) ( 984 )  

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vehicle rollover is a kind of fatal accident.The vehicle rollover warning system is designed to solve this problem.The system consists of circle of microprocessor and circuit of sensor and rollover alarm unit.The central data processing unit mainly consists of STM32 embedded processor.The embedded system has the character of small volume and lower power consumption,suitable for long time running.

Research on Ultrasonic Concrete Nondestructive Testing

YANG Mu,LIU Lulu,ZHANG Ming,LAN Yuan,QIU Xuanbing,WEI Jilin

. 2013, 26(5):  9. 

Abstract ( 934 )   PDF (793KB) ( 892 )  

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This paper describes the basic principles of ultrasonic nondestructive testing.Two testing methods of concrete defects are introduced,namely ultrasonic single side method and vertical side method.A detection system with STC89C52 chip as the core is designed.The system has the advantages of simple structure,low power and portability,and improves the safety of structures.

3D Image Quality Assessment Database

HE Wenqing,XU Manfei,WU Yuanyuan

. 2013, 26(5):  13. 

Abstract ( 800 )   PDF (652KB) ( 889 )  

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3D technique is used widely with rarely effective assessment method.A main reason for this is lacking of 3D image database.What we have done is to solve this problem.The images with the highest score for each scene in EPFL database was chosen for distortion.The type of the distortion were JPEG,JPEG2000,Gaussian white noise and Gaussian Blur.Five different levels for each distortion is used to be assessed.At last,we used PSNR,the most common method,to verity the score.

The Design and Application of instructions of Pulse Output on PLC

WANG Xudong

. 2013, 26(5):  16. 

Abstract ( 943 )   PDF (600KB) ( 826 )  

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PLC control system of card clothing machine as an example in this paper.This plan selects CPM2A PLC which OMRON Corporation produces to take the core of control system,the design and application of instructions of pulse output is introducted.For the existing control system,we provide the development of ideas of controlling stepper motor speed and location of stepper motor based on PLC,the hardware and software In this paper.

Research on and Development of Embedded Cross Debugging Environment MRTOS Based on Eclipse Platform

LIU Fang,ZANG Wei

. 2013, 26(5):  18. 

Abstract ( 937 )   PDF (663KB) ( 847 )  

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The cross debugging technique is essential to the development of embedded systems.In this paper,adopting PowerPC755 as the CPU of the target debugging terminal,an integrated development environment,MRTOS,is designed and implemented based on Eclipse platform.The environment demonstrates satisfactory compliance with the general cross debugger-GDB and good competency in source code debugging of the object program running on PowerPC755.

A Method for Making Oblique Rectangle by Using the Photorepeater

HUANG Dihui,HUANG Zhengyu

. 2013, 26(5):  22. 

Abstract ( 769 )   PDF (592KB) ( 735 )  

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A mathematical model of making oblique rectangle by a smaller rectangle is proposed and a procedure based on this model is programmed.By means of the procedure and a particular diaphragm,the photorepeater acts as a pattern generator.The oblique rectangles without any jagged edge are made accurately.It is a practical method for making particular photomasks.

A Web-based IPTV Experimental Platform System Design

YAN Lei,LI Yinfeng

. 2013, 26(5):  24. 

Abstract ( 832 )   PDF (666KB) ( 761 )  

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Explains the overall architecture of the Web-based IPTV system,indicating that the basic idea of the system design,and by Part 3 demonstrates IPTV experimental platform system as a streaming media server,Windows Media Server,a video-on-demand and live function build process.User through a computer terminal connected system,not only to achieve a live television programs,video-on-demand,and can also be used as a wide variety of academic report,live broadcast platform for large-scale events,with high practical value.

On-line Monitoring System Based on Double-Service WSN of Distribution Network

TIAN Xiaomin

. 2013, 26(5):  27. 

Abstract ( 1057 )   PDF (568KB) ( 741 )  

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In order to solve the problem of laying wired power cable and communication cable,an on-line monitoring system of smart distribution network based on double-service WSN is presented in this paper.The system is based on service-oriented,and has double-layer service structure and data access interface to describe the service distributing and establishment.Compared to layer-oriented system,our system is simple and effective.Further more,the presented service structure also can reduce node Energy consumption and improve the network service.

Design of a GPS Data Acquisition Analyzer

LEI Juan,LIU Wenxia

. 2013, 26(5):  30. 

Abstract ( 851 )   PDF (703KB) ( 835 )  

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GPS data acquisition analyzer in the PC software is connected via serial port to the GPS receiver,responsible mainly for the collection and analysis of GPS data.A complete set of GPS data information is obtained and analyzed of its statement in accordance with GPS data format in the UBX and NMEA protocol to extract the location information,visible satellite information,etc.

Realization of a Video Monitoring System Based on Embedded ARM

ZHANG Kai,LI Linsheng

. 2013, 26(5):  34. 

Abstract ( 806 )   PDF (595KB) ( 821 )  

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This paper introduces a video monitoring system used in intelligent home furnishing.Based on an analysis of the embedded technology,this paper proposes and realizes a wireless video surveillance solution which combines the characteristics and advantages of wireless LAN with the embedded system.The system adopts ARMS3C2440 processor as the core of hardware platform,using Video4Linux2 USB camera to collect video image data,which are transmitted through the UDP network protocol and finally received and displayed real-time on the PC with the program designed by the SDL database.

Efficiency Optimization of the EV-motor Control System

ZHOU Yawei,NIE Jianhua

. 2013, 26(5):  37. 

Abstract ( 903 )   PDF (652KB) ( 926 )  

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An improved strategy was proposed for the efficiency optimization of EV-motor control system.Based on the power loss model of PMSM,the relationship between system loss power and stator flux linkage is deducted and the optimal flux is related to stator resistance.A stator resistance compensation scheme is presented based on wavelet neural network to address the difficulty in accurately calculating the optimal flux with dynamic stator resistance present.The validity of the proposed strategy is proved by the simulation of the system model using matlab/simulink.

A Research on and Implementation of Embedded Remote Data Collection and Transmission Technology

YU Songtao

. 2013, 26(5):  41. 

Abstract ( 924 )   PDF (545KB) ( 892 )  

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RDC is a low-cost,line replaceable sub-module designed as an Integrated Modular Avionics building block,which provides a scalable remote interfacing capability.Its prime role is to provide the interface between a variety of subsystem sensors,effectors and the ICPs via a system databus,such as AFDX,AS5643 or ARINC429.

Design of an Item Bank System Based on C-B/S Architecture

ZHANG Xueya

. 2013, 26(5):  43. 

Abstract ( 849 )   PDF (764KB) ( 765 )  

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The division of roles,architecture design and platform design are discussed.A C-B/S hybrid architecture of the new test database system construction model is proposed.Requirement analysis is made of Baoji University of Arts and Sciences to describe the functional modules,platform architecture and other aspects of the platform design.Informatization of academic affairs,student and library management is realized by this system,which enriches teaching methods and improves teaching efficiency.

Smart Shade Control System Based on the Artificial Neural Network Model

XIONG Aimin,XIE Xuan,FANG Jiangsong

. 2013, 26(5):  47. 

Abstract ( 915 )   PDF (866KB) ( 808 )  

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This intelligent network of sunshade control system is based on artificial neural network model and complied with Lonworks bus.It uses a variety of sensors to detect indoor and outdoor light intensity and temperature automatically.It calculates reasonable curtain height and blade angle using the fuzzy algorithm and building shadow model.After multi parameters data analysis,it adjusts the overall building outdoor shade panels and interior blinds by AC/DC motor.Furthermore,it reduces building energy consumption using indoor lighting and air conditioning temperature controlling module.This system adopts TCP/IP protocol to connect building automation system (BA) seamlessly.

Research on the 250 W CW Ka-band TWT Transmitter

SHI Liyong,CHANG Li

. 2013, 26(5):  50. 

Abstract ( 875 )   PDF (592KB) ( 898 )  

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The travelling wave tube (TWT) transmitter is researched in view of the application demand.The gain of transmitter is greater than 70 dB,saturated output power is more than 250 W,and 1 dB compression point output power is greater than 160 W with an efficiency of 40%.In case of a 7 dB backoff from 1dB compression point,the three order intermodulation is -35 dBc.

Design and Implementation of Embedded Communication System Based on FPGA Picoblaze

ZHANG Kun

. 2013, 26(5):  53. 

Abstract ( 911 )   PDF (641KB) ( 880 )  

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This paper studies the application of KCPSM in the design of a Picoblaze embedded communication system with Xilinx Spartan 3E FPGA.The system realizes data communication and display via the module of nrf2401.After the research on the system hardware theories and functions,KCPSM is applied to design FPGA Picoblaze IP core for the control of nrf2401 moduel,thus realizing analog and digital data communication.

Design of the FPGA-based HB6096 Bus Communication Board

ZHANG Zhen,BAI Xi

. 2013, 26(5):  57. 

Abstract ( 920 )   PDF (625KB) ( 977 )  

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HB6096 bus is an aero industry standard used in data transmission between avionics equipments.A HB6096 bus communication interface card design based on FPGA is put forward.This scheme saves hardware resource efficiently by achieving multi HB6096 bus communication on one board.This system can successfully run in practical applications.

A High Gain Microstrip Array Antenna Using Fractal Structure

YU Lei,CHEN Xing

. 2013, 26(5):  60. 

Abstract ( 978 )   PDF (703KB) ( 1096 )  

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By using the second iteration Peano curve,a microstrip array antenna with high gain and end-fire characteristics is proposed.This array antenna consists of several Peano fractal curves,in which some microstrip phase shift sections are inserted to create a dipole array.The principle of this fractal array is introduced,and the effects of some important structural parameters on the antenna's performances are analyzed.Finally,a proposed fractal array antenna working at 5.8 GHz is designed and fabricated.Both simulated and measured results show that the antenna has excellent radiation performances,e.g.the end-fire gain is 19.0 dBi,the side-lobes are approximately 12 dB below the main lobe,the cross-polarization level is less than -30 dB,and especially the array's aperture efficiency is greater than 90%.

Time-domain Method for Reflection Wave Elimination for Mobile Communication Base Station Antenna Testing

AN Zhihuai,WANG Xinglin,LI Shengli

. 2013, 26(5):  64. 

Abstract ( 907 )   PDF (822KB) ( 824 )  

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Testing results of mobile communication base station antenna index are serious impacted by reflected wave.The time difference of the reflected wave and the direct wave is related to the location of the reflection point,the antenna length and other factors.The time difference is computed,and a time-domain method is proposed for the elimination of the reflection of the test site of greater value than the specified one.Theoretic analysis and real testing show that the method can lessen the influence of the reflected wave effectively with more accurate testing indexes.

Design of the Temperature Acquisition Circuit of the Solar Generator Control System

DING Fu,ZHOU Hanyi,RUAN Qingliang,REN Jinpeng

. 2013, 26(5):  68. 

Abstract ( 943 )   PDF (705KB) ( 1033 )  

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A design of K-type thermocouple multi-channel temperature acquisition circuit based on AD7606 is introduced,which adopts the Stirling solar power control system.Thermocouple and AD converter chip AD7606 collect data,which are processed by the microcontroller before being transferred to the host computer.The experiment shows that the design function can meet the technical requirements of stability,high accuracy,and high resolution in temperature measurement.

Application of Matlab Fixed-point Simulation to the Verification of FPGA

SU Li

. 2013, 26(5):  71. 

Abstract ( 1007 )   PDF (710KB) ( 1184 )  

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Both in the radar system and the communication system,when simulating its various signal processing methods,Data participates in computing in the form of floating-point,while the algorithms are implemented in hardware (FPGA),The data participate in the operation in the form of fixed-length binary.This article firstly describes how to use Fixed-Point toolbox to achieve the data conversion from the floating-point to the fixed-point.Finally,an example is designed to describe the application of fixed-point simulation to the verification in FPGA.Experiments show that,The fixed-point simulation is the basis of the implementation of FPGA,and also verify the correctness of the result of FPGA.

PDN design method based on improved target impedance

QIN Jun,LI Weizhe

. 2013, 26(5):  74. 

Abstract ( 917 )   PDF (987KB) ( 1004 )  

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To solve the over design problem which is brought by the traditional target impedance in PDN design,a PDN design method based on an improved target impedance is proposed.What is different from the traditional target impedance,the proposed impedance is the combination of resistance and inductance and it shows as rising frequency-impedance curves.In the practical operation,the combination which uses the minimum decoupling capacitors (decaps) is selected as the best target impedance.A PDN design tool has been implemented in Matlab,and practice shows that compared with the method which use the traditional target impedance,the proposed method use less decaps and has a strong practicability.

Design and Realization of a Complex Waveform Signal Generator

YU Tiejun,YOU Fabao,REN Yaxin

. 2013, 26(5):  78. 

Abstract ( 790 )   PDF (750KB) ( 795 )  

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The design and realization of the complex waveform signal generator are introduced in this paper.The high-speed direct digital synthesizer is used to generate various complex waveform signals,and the frequency multiplication will be performed for the complex waveform signals generated by the DDS with the MW broad band frequency multiplier to achieve the expansion of the DDS output signal bandwidth to generate the complex waveform signals with various bandwidths.The designed complex waveform signal generator is capable of multiple complex waveform signals such as linear frequency modulation signal,nonlinear frequency modulation signal and phase encode signal,with an output signal bandwidth up to 1 GHz.

Analysis of the Dynamic Voltage Restorer Control Strategy

WU Guifeng,WANG Xuan,ZHANG Haifeng

. 2013, 26(5):  81. 

Abstract ( 935 )   PDF (906KB) ( 701 )  

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Dynamic voltage restorer is considered to be one of the effective means to solve power quality problems such as voltage sag.DVR control strategies include feedforward control,compensation voltage feedback control and composite control strategy.The basic structure and working principle of the DVR on the voltage drop detection methods are introduced,the dynamic voltage restorer (DVR) control strategy is analysed,and the advantages and disadvantages of the three control strategies are pointed out.A DVR mathematical model is established and simulation verifies the feasibility and effectiveness of the DVR.

Integration of the Ka-band Transceiver

WU Xiaoshuai,WANG Guide,MA Zhangang

. 2013, 26(5):  84. 

Abstract ( 944 )   PDF (707KB) ( 880 )  

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The integration of the Ka-band transceiver has significant effect on the system noise factor,sensitivity,and other key indicators of the wireless communication system circuit.The working principles of the integrated Ka-band transceiver with the overall block diagram given.A detailed analysis is made of design of the receiver channel unit,the local oscillator unit,emission channel unit,and power control unit and both simulation results and test results are provided.The results show that with a noise factor ≤ 2.2 dB,gain ≥ 60 dB,the input and output standing wave,the phase noise spurious image rejection and other indicators of the integrated Ka-band transceiver all meet the technical requirements;with the transmitter 1 dB compression point power ≥ 30 dBm and gain ≥ 50 dB,the TOI,clutter suppression also satisfy the technical requirements.And in accordance with the test results,part of the technical indicators of the integrated Ka-band transceiver are optimized and improved.

Analysis and Simulation of Automatic Compensation Device in the Low-voltage Power Grid Tuning Capacitors

WANG Zhao,HUANG Xiaowei,LIU Yi,WANG Dong

. 2013, 26(5):  88. 

Abstract ( 847 )   PDF (765KB) ( 729 )  

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The tuning capacitors automatic compensation device development status and problems are reiviewed.Its working principles and hardware and software design are introduced.The proposed tuning capacitors arc suppression coil design is based on DSPTMS320F2812 control thyristor switched capacitor.Experiments show that in case of single-phase ground,dynamic fast-track for automatic compensation of the ground point capacitive current can suppress the arc.

Hardware Design of a Universal Radar Signal Processor

ZHOU Jie,LI Xiaojuan,ZHANG Wei,QUAN Yinghui

. 2013, 26(5):  91. 

Abstract ( 1188 )   PDF (672KB) ( 856 )  

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A design of universal radar signal processor is proposed with great data storage capacity and high-speed ADC,high-performance DSP+FPGA as the core.Highly integrated,easy to be reconstructed,and highly adaptable to algorithms,this platform can shorten the development period of new radars.

Design and Application of a High Accuracy Intelligent Electric Meter System

ZHANG Cheng,HE Dafei

. 2013, 26(5):  95. 

Abstract ( 962 )   PDF (511KB) ( 669 )  

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The design of smart meters is discussed with the ARM7 as the processor and ATT7022 as the core metering chip to collect power signals for power monitoring,real-time measurement,memory and processing,and remote transmission operation.Application shows that this meter,with LCD display and remote communication interface,achieves remote meter reading,meets the industrial requirements of smart meters.Small in error and low in cost,this meter has a broad application prospects.

Design of an Electronic Remind Device

WANG Yongzhong

. 2013, 26(5):  98. 

Abstract ( 843 )   PDF (720KB) ( 707 )  

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The Electronic Remind device is a novel and practical electronic product,which can be widely used in households and offices.Our design uses MCU AT89C51 for controlling the voice chip ISD4004,the time clock chip DS1305 and the LCD display.The functions and operations are expounded.The keynotes of software and hardware design of the electronic reminder are presented.

WSNS Outlier Detection Based on Fusion-Bayes

XU Suya,HU Caiping,WANG Lisong

. 2013, 26(5):  102. 

Abstract ( 849 )   PDF (824KB) ( 738 )  

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With the rapid development of wireless sensor network,the amount of data acquisition as well as the dimensions of data increases constantly.However,the existing outlier detection algorithms are mostly used for single or low dimensional data.This paper presents an outlier detection technique based on Fusion-Bayes.This method first uses the data fusion to converse data from different sources into the same form,and then uses a Bayesian method to detect outliers of different attributes.Experiments show multidimensional data attribute fusion detection is more accurate and the more effective compared to the single dimension attribute or low dimension attribute detection.

Sparse Reconstruction Algorithm

WANG Hansan,CHEN Jie

. 2013, 26(5):  106. 

Abstract ( 990 )   PDF (453KB) ( 722 )  

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In image processing and statistics,to find a sparse approximate solution for a large underdetermined linear equation is a common problem.The standard method is to look for the minimum value of an objective function,which includes a quadratic l₂ error term added to a regularizer l₂.For the more general problem,we propose an algorithm,where the objective function is made up of a smooth convex function and a nonsmooth regularizer.The algorithm obtains the sparse approximate solution by solving the optimal sub-problems.The simulation result shows that the algorithm can find the approximate solution quickly and the minima solution of the function is convergent under the conditions namely convexity of the regularizer.

Research on Fault Detection of FPSO Process Based on KPCA

HAO Xiaopeng,ZHAO Hongye,GAO Qiang

. 2013, 26(5):  109. 

Abstract ( 822 )   PDF (682KB) ( 638 )  

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This paper analyzes the basic principle of Kernel Principal Component Analysis.The sample data are mapped to a higher dimensional space to detect the fault by using the Gaussian kernel function to solve the small samples and nonlinear problems.The kernel principal component analysis method is used to detect the fault validity in the production of floating storage and offloading systems.

A Fast Handover Scheme Based on Feature Projection for Mobile IPv6

TANG Jun

. 2013, 26(5):  112. 

Abstract ( 864 )   PDF (610KB) ( 1103 )  

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The handover of mobile IPv6 is investigated.Based on the feature projection mechanism,a new fast handover scheme for mobile IPv6 is proposed.The scheme constructs mapping relations between prior handover experience and coverage area of a Mobile Access Gateway to help predict the next MAG after handover.Simulation results indicate that the proposed scheme can achieve better performance with better robustness in terms of handover latency and packet loss compared with FMIPv6.

Reactive Power Compensation Optimization Algorithm for the Low Voltage Distribution Network Shunt Capacitor

LU Yang,LIU Chenfang,LAN Caijin

. 2013, 26(5):  115. 

Abstract ( 978 )   PDF (520KB) ( 788 )  

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In view of the low voltage,high current and high line loss in low voltage distribution network,a reactive power compensation optimization algorithm is proposed to minimize the line loss,thereby effectively determining the best installation location and compensation capacity of the distribution line compensation capacitors.Compared with the traditional approximation algorithms and the 2n/(2n+1) algorithm,our algorithm is more economic and effective.

Research on Opportunistic Network Routing Based on Community Structure

MA Heng,DU Qingwei

. 2013, 26(5):  117. 

Abstract ( 1014 )   PDF (765KB) ( 1130 )  

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Currently,the study on opportunity network based on community structure remains to be improved,since the routing algorithm dose not take the transmission efficiency of the message into account between different communities,and in the community the routing it only use simple Spray and Wait routing algorithm,making opportunistic network based on community structure less efficient.To address these issues,the community model has been improved with the factors of node regression in mind,and a new routing algorithm called Node Back Routing under the improved community model is proposed.In the community,the routing algorithm uses the hybrid routing rules,and adds the positive feedback to recalculate the activity of the nodes.In different communities,the routing algorithm uses query routing table and considers the node regression method,making use of the attributes of the node regression to improve the efficiency of the message forwarding.Simulation results show that the improved community structure and routing algorithms improve the message transmission rate between different communities and in the same communities and effectively reduce network consumption.

Research on the Priority Queue Scheduling Algorithm Based on QoS

ZHOU Peng,HAO Ming,TANG Zheng,HU Junfeng

. 2013, 26(5):  122. 

Abstract ( 1042 )   PDF (515KB) ( 826 )  

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To satisfy the requirements of the QoS in the wireless network,three classical priority queue scheduling algorithms are discussed in this paper,namely Round Robin (RR),Priority Queuing (PQ),and Proportional Fairness (PF).The principles,advantages and disadvantages of the three algorithms are studied,and finally a practical one is chosen through computer simulation.

New Variable Step Size LMS Adaptive Algorithm

YANG Feifei,YIN Yafang

. 2013, 26(5):  125. 

Abstract ( 910 )   PDF (667KB) ( 658 )  

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The problem of step size selection for adaptive least mean squares (LMS) filtering algorithm is studied.A new variable step size LMS algorithm with improved hyperbolic tangent function is presented,which is derived by an extensive review of existing LMS algorithms.With the same convergence properties,the new algorithm has less excess mean square error (MSE);and with the same excess MSE,it has better convergence properties.Computer simulation results confirm the theoretical analysis and show that the algorithm is superior to the former algorithms in performance.

Directional/Omi-directional Routing Simulation Based on Matlab for Ad Hoc Networks

PAN Jiyuan,HAN Chunlei

. 2013, 26(5):  128. 

Abstract ( 901 )   PDF (955KB) ( 769 )  

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In this paper,we qualitatively analyze the performance of directional and omi-directional routing protocols for Ad Hoc network.For this purpose,we perform simulation analysis on AODV and its directional variant with greedy transmit strategy based on MATLAB.The simulation results demonstrate that the performance of directional routing is better than that of omi-directional routing according to the number of hops when mobile nodes are collocated by Normal or Poisson distribution.

Study of Data Link Integration Application of US Army

TIAN Wanyong

. 2013, 26(5):  133. 

Abstract ( 1131 )   PDF (573KB) ( 1010 )  

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In view of the coexistence of a variety of tactical data links in US army,integration application is the basis for fully playing their roles.In this paper,the data link integration application of US army is studied and the characteristics of some typical data links are introduced with emphasis on the functions,principles and characteristics of Common link integration processing (CLIP).The trend of data link application of our army is also analyzed.

A Congestion-aware Multipath Routing Algorithm for Wireless Ad hoc Networks

YUAN Yongqiong

. 2013, 26(5):  135. 

Abstract ( 795 )   PDF (693KB) ( 548 )  

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A Congestion-aware Multipath Routing (CMR) algorithm for wireless ad hoc networks is presented in this paper.In the route discovery,the probability of each node forwarding rout is dynamically adjusted according to the queue size and the number of route hops in route request message.This strategy could reduce network routing load,and guarantee the most nodes to receive the packet.In the route selection and demands distribution,the proposed algorithm is based on the node queue length and the link quality as routing metric to find high throughput and low congestion routes and to distribute the demands among the multiple paths.Simulation shows that the proposed multipath routing algorithm can significantly improve the network performance.

A Data Link Service Quality Assurance System

LI Tianrong

. 2013, 26(5):  139. 

Abstract ( 844 )   PDF (582KB) ( 834 )  

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The mainstay of the network central war is data link.According to the requirements of the network central war,data link is a system of several layers.Based on the analysis of the requirement of QoS of different layers and the characteristics of different data links,this paper proposes a systematic and multi-mode scheme to achieve the QoS requirements.

CAZAC Sequence-Based Underwater Acoustic Communication Technology Research

DU Ligang,YANG Li,SU Jiancai

. 2013, 26(5):  142. 

Abstract ( 1035 )   PDF (667KB) ( 754 )  

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In view of the fact that the CI/OFDM system is sensitive to synchronization,this paper puts forward a time and frequency synchronization algorithm based on CAZAC sequence.The time offset estimation and carrier frequency offset estimation can be achieved by this algorithm.Simultaneously,the fractional part and integral part of carrier offset estimation can be respectively obtained by the correlation result of time offset estimation and cyclic correlation principle.The simulation and experimental results show that in the underwater acoustic channel,the algorithm has a better time-frequency synchronization performance.

Subcarrier Selection in Cooperative OFDM Networks

DIAO Xinying

. 2013, 26(5):  146. 

Abstract ( 914 )   PDF (494KB) ( 448 )  

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A cooperative relaying scheme using OFDM modulation is studied and a subcarrier selection in cooperative OFDM system is proposed.To maximize the system capacity,subcarriers based on the channel information are chosen to improve the capacity of the system by using the relay station to amplify-and-forward the signal.Result shows that in lower relay/resource power ratio or in the circumstance that the relay is in the middle of the resource and destination station,using all subcarriers to relay would decrease the capacity.The subcarrier selection can improve the capacity.Suitable relay/resource power ratio and relay position would significantly improve the capacity of the system.When the relay station is in the middle of the resource and destination station,the capacity is maximized.

Design of a Photovoltaic Analog Power Supply

LI Fan

. 2013, 26(5):  149. 

Abstract ( 860 )   PDF (552KB) ( 446 )  

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In order to test the maximum power point performance of the photovoltaic inverter,this paper designs a  photovoltaic analog power supply.Analog power is mainly composed of rectifier filter circuit and DC/DC power component.Rectifier filter circuit converts alternating current into DC and the switch power supply achieves the decompression function.The output voltage sampling is fed into the error comparator to be compared with the voltage across the controller RAM to control the output current and voltage for it to work in the corresponding I-Vcurve.The proposed design can simulate the solar pv curve by manually inputting temperature and sunshine intensity.

Application of the Phase-locked Loop in the Photovoltaic Power Generation System

LI Xiaofei

. 2013, 26(5):  151. 

Abstract ( 1066 )   PDF (532KB) ( 670 )  

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The phase-locked loop is an important part of photovoltaic power generation system and network.The main role of the phase locked loop is to maintain a fixed phase difference value of the input and output voltages when the frequency of the input and output signals are equal,i.e.,the phase of the input and output voltage is locked.This paper introduces the working process of the three parts of a phase-locked loop.The combined phase-locked chip CD4046 achieves the collection of voltage signal frequency and the phase data locking,and through the lock,and the loss of lock signal input inverter.When there is a serious deviation of the phase,frequency and amplitude of the inverter output voltage from the normal grid value in the photovoltaic power generation system,an alarm is sent for the grid separation by isolating the switch.

Radar Brush Wire Conductive Ring Palladium Nickel Alloy Coating Technology Research

WU Xiaoxia

. 2013, 26(5):  154. 

Abstract ( 720 )   PDF (569KB) ( 457 )  

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Palladium nickel alloy technique is adopted for the radar brush wire conductive ring.Metallization is conducted on aluminum bronze material of conductive ring to wear resistance palladium nickel alloy membrance layer structure,so as to meet the wear-resisting and conductive requirements.The palladium ion concentration parameter change in the palladium nickel alloy solution and its influence on brush wire surface thickness is studied.Combined with the experiment results of gold plated layer,the article analyzes the reasons of various phenomena.

Research on and Implementation of Protective Mechanism of Trojan Based on NDIS Intermediate Layer

HONG Shuangxi,LEI Tao

. 2013, 26(5):  156. 

Abstract ( 846 )   PDF (702KB) ( 645 )  

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Through analyzing the characteristics,types and communication mode of the Trojan program,a protection mechanism in kernel level based on NDIS intermediate driver technique on the windows platform is put forward.IP address and port number and the process of captured data packet are analyzed and judged to realize interception of Trojan virus communications and the identification of Trojan process.With the same interception rate of Trojan communications,it is obviously superior to the similar functional anti-Trojan software in the data packet processing speed.

Development and Prospect of Image Contrast Enhancement

WANG Junping,LI Jin

. 2013, 26(5):  160. 

Abstract ( 1766 )   PDF (877KB) ( 1902 )  

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Image contrast enhancement is an important research content in the field of image processing technology,and it can extend the gray-value dynamic range.The technology significantly improves the visual effects and provides processed images more suitable to analyze.Image contrast has been studied for decades.However,with the change of the original image characteristics and application requirements change,the image contrast enhancement research continues to proceed.This paper systematically introduces the purpose and the current research status of image contrast enhancement,and analyzes the characteristics and limitations of the mainstream algorithm about image contrast enhancement in recent years.Finally,this paper points out the future direction of the image contrast enhancement technique.

a New Subdiscipline of Linguistic Science-Natural Language Processing

SHAO Zeguo

. 2013, 26(5):  166. 

Abstract ( 933 )   PDF (715KB) ( 613 )  

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The desire for the computer to possess the ability of human language has driven language sciences to be combined with computer science,thus a new interdiscipline,which has different definitions and naming from different disciplinary perspectives.In this article the author discusses the new subject of natural language processing from the science of language perspective,covering the concept,the development and current status of natural language processing with emphasis on the discussion of the significance and methods of natural language processing.

Common Failures and Method of Power Distribution Room

YANG Yeping

. 2013, 26(5):  169. 

Abstract ( 700 )   PDF (579KB) ( 548 )  

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In order to protect the power distribution room to normal operation,the paper introduces the common fault for power distribution room:power room of a three-phase fault,transformer fault protection device failure,corresponding to each failure occurs when the condition and treatment.Useful reference for the maintenance of effective control and power distribution room for common faults.

Harmonic Detection and Treatment of the Power System

TIAN Zhixin,QIAN Xianchun

. 2013, 26(5):  172. 

Abstract ( 908 )   PDF (594KB) ( 550 )  

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With the constant improvement of the electric power applications,power harmonics problems,especially the harmonics generated harm,have aroused widespread concerns of the industry users.The detection,elimination and management of the harmonic current have become a top priority in the attempt to comprehensively improve the quality of service of the grid.This article analyzes the harms harmonic current might do,discusses the detection methods,and proposes some methods for the elimination and management of harmonic current with desirable effects.

Intrinsically Safe Behavior Assessment of Explosion-proof Electrical Apparatus and Electric Circuit

ZHAO Man

. 2013, 26(5):  174. 

Abstract ( 1002 )   PDF (557KB) ( 626 )  

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The development history of intrinsically safe theory,the methods and standard for intrinsically safe behavior assessment of explosion-proof electrical apparatus and electric circuit are introduced in this paper.The explosion assessment method and non-explosion assessment method for intrinsically safe behavior assessment of electric circuit are also covered.Three latest domestic non-explosion assessment methods are analyzed and summarized.It is pointed out that the intrinsically safe behavior assessment of intricate electric circuit is the future trend.

Analysis of the Current Situation of the Characteristic Database of “211 Project” University Libraries

YUN Guangping,LI Yubin,SU Liubang

. 2013, 26(5):  177. 

Abstract ( 900 )   PDF (539KB) ( 793 )  

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Library databases of electronic resources in the last ten years have been developing rapidly,and have substituted the paper resources as the major information acquisition method of library users .The construction of database resources has gradually evolved into the core of the library automation.An investigation and analysis is made of the present situation of Shaanxi “211 project” university library characteristic database resources,the existing problems are pointed out,and the countermeasures are presented.

Electrical Engineering Curriculum Reform Based on the Concept of CDIO Engineering Education

HAO Qian,WANG Liming,YANG Feng,LI Xiaoming

. 2013, 26(5):  180. 

Abstract ( 771 )   PDF (568KB) ( 595 )  

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In view of the lack of the training of students' practical and innovative ability by traditional teaching mode,this article adopts the CDIO engineering education model,which applies the core concept of “idea-design-implementation- operation” throughout the entire teaching process.The practice of teaching reform shows that the CDIO-based curriculum has obvious advantages,effectively enhancing the cultivation of students' practical engineering ability and innovation ability.