Abstract:The actual rough land surface is simulated with the exponential type distribution rough surface and Monte Carlo method, the wideband back electromagnetic scattering from rough land surface and column with equilateral triangle crosssection above it under UWB Gaussian pulse electromagnetic wave incidence is studied using FDTD. The curves of back electromagnetic scattering coefficient varied with frequency are obtained by numerical calculation. The back electromagnetic scattering coefficient varying with frequency is analyzed under the difference of the rootmeansquare of rough land height fluctuation, correlation length and the moisture capacity of soil, the side length of triangle, tilt angle, height and dielectric parameter. The characteristics of the wideband back electromagnetic scattering from rough land surface with the exponential type distribution and column with equilateral triangle crosssection above it are obtained.

Abstract:In the coal mine high voltage power supply system, the protection setting value whether meets the selectivity and reliability cannot be determined by short circuit experiment in the field, so this paper propose the simulation test system of protection setting value in coal mine underground high voltage network, to simulate the selectivity and reliability of underground flaut detection protection setting value. The whole design scheme of simulation protection setting value in coal mine underground high voltage power network is introduced, breadthfirst search algorithm based topology selflearning of coal mine underground supply systems is carried out, based on the obtained topology model, the simulation calibration algorithm of the fault current calculation, timing overcurrent protection, transient speed circuit protection and overload protection is proposed. The experimental results show that the system can test whether the coordination between timing overcurrent protection and transient speed circuit protection is reasonable, and whether the current settings of each segmental will cause blackout area expanding, and effectively realize the simulation test of underground highvoltage power system relay protection setting.

Abstract:The solderability tester is an instrument which is used to test the solderability of the electronic components during the producing process, screening retests and before loading the system. Time parameter is an important index for solderability tester. Mainly on the specimen dipping duration time for research is discussed. After analysis the traditional counting method, we put the time interval measurement into the calibration for component solderability tester, and assess the measurement uncertainty of specimen dipping duration time. In this paper, the results show that compared to the traditional method, time interval measurement is simpler and more obvious. The problem of calibration for solderability tester is solved.

Abstract:Steadystate methods and transient methods can't give the accurate results when the coupling impedance and threephase unbalance load exist in power system. In this paper, the improved steadystate method is proposed to obtain the system harmonic impedance. Firstly, the phasemode transformation matrix is calculated which can decouple the three measurements into a set of single variables and simplify the calculation process; Secondly, singlephase model is established by MATLAB/Simulink to compare steadystate methods with transient methods; Thirdly, threephase model is established which exists the coupling impedance and threephase unbalance load. The steadystate methods and the improved steadystate methods is applied to calculate the the system harmonic impedance. The results show that the steadystate methods is more accurate than the transient methods and have less interference; The steadystate methods is improved by the phasemode transformation and the improved methods is selected to obtain the system harmonic impedance which improves the accuracy and simplifies the process of calculation.

Abstract:Voltammetry is a common method for measuring resistance, the resistance error sorter is a widely used measuring instrument. In some specific applications, users have special interest on the deviation of the measured resistance relative to a reference resistor. The purposed design is based on such specific application requirements and to develop a resistance error measuring instrument. The measuring instrument uses a constant current power supply, the measured value is processed by the operational amplifier, the analogtodigital converter, and presented in an intuitive digital form. The instrument haslow measurement error and easytouse features. By analyzing the frontend signal processing circuit of the measuring instrument, this article explains the design scheme, structure principle and component selection basis of the instrument. It discusses the additional error of the measurement results caused by the local circuits, with a quantitative estimatation of the size of the error, and provided counter measures in this regard. Eventually, the analysis of the test error calculation proves that the measuring instrument has met the measurement accuracy requirements.

Abstract:The influence of modulation rate on energy efficiency (EE) and the various system parameters on the optimal EE for a sourcerelayterminal communication link using amplifyandforward (AF) protocol and MQAM are studied when bit error rate (BER) is prescribed. First, the transmission power consumption is calculated, then the total power consumption can be obtained when circuit power consumption and demodulation energy consumpton are taken into account. Finally, the expression of EE is derived and the influence of modulation rate on EE is studied. Through simulation results we find that when the modulation rate increases, the energy efficiency first increases and then decreases. When the error rate increases, the optimal EE strictly increases, the optimal modulation rate strictly decreases. When increasing the circuit power consumption, the optimal EE strictly decreasing and the optimal modulation rate strictly increasing. When the initial energy consumption increasing with ML demodulation receiver, the optimal EE strictly decreasing and the optimal modulation rate strictly increasing.

Abstract:Nowadays, the large radio telescope projects have received widespread attention within every country . However, more and more demands on the market are the small radio telescopes or scientific series. For large radio telescope antenna, the demand of accuracy for the pointing is high, all kinds of real time correction need to be done in the process of observing, the investment in control module is enable, mostly using closedloop computer control program. Although the control method has obtained the good effect in the large radio telescope, but for the small,the expensive cost and complex control methods are not applicable. So, in this paper, through practical investigation, the button control circuit is used to control the MCU work mode to replace the original large console, and the control system can be applied to small antenna with a lot of debugging.

Abstract:Traditional firstorder extended Kalman filter algorithm is widely used in various types of shells extrapolation filter,and it requires continuous occupancy of radar’s time resource. The hybrid model Kalman Filter algorithm which is based on the Least Squares Filter and the EKF contrapose the mortar’s movement characteristics of the small initial velocity and big launch angle,using flexible segmented sampling,realize good extrapolation of mortar’s movement .The simulation show that,the algorithm has the similar accuracy to the EKF in different launch angle and azimuth and even better in high launch angle, takes less resources,has good realtime performance,and it is suitable for practical engineering.

Abstract:Nowadays many watermarking algorithms have been proposed and implemented for images and video. Compared to the human visual system, the sensitivity of the auditory system makes the audio watermarking more difficult to realize. In order to improve the invisibility of the audio watermarking,this paper presents an audio watermarking algorithm which is based on the quantization of discrete cosine transform (DCT), first the original audio is divided into two parts due to the energy, and do the discrete cosine transform on the larger part, then the Arnold scrambled binary watermark image is embedded into the mean value of the middle frequency coefficients using quantitative index modulation (QIM),And ensure that the embedding watermark on the original audio within the range of hearing range. Experimental results show that the algorithm has good invisibility, and have robust of MP3 compression and noise.

Abstract:DataSocket is a kind of realtime transfer technology in LabVIEW,which has some advantages such as fast speed,easytoprogram,supporting multiclient,and can be used to transfer images. A set of LabVIEW programs including DataSocket were designed to research the speed of transfering images through DataSocket from server PC to client PC.Since receiving one image took more time than sending one,server must delay several miliseconds after sending out one image which meant that the shorter delay time, the faster tansfer speed was.Once the shortest delay was recorded,the highest transfer speed could be figured out. According to the result,transfer speed difference is related to image format,the fastest one can reach 31 MB/s after compressing within 300 M bandwidth local area network;Images with the same format but different sizes have similar transfer speed and smaller ones’ is a liitle faster than big ones’.

Abstract:The paper analyzes the existing technique of VLPR, and then proposes a kind of license plate recognition system based on FPGA. The paper introduce the idea of designing system and the method of designing circuit by using FPGA in detail. And it also shows the actual test results. Compared with the previous system based on PC and DSP, the FPGA system is characterized in smaller size, faster computing speed and higher accuracy of recognition. After the test of more than 100 license plate images captured under different environments, the results show that the recognition accuracy is above 98%.

Abstract:For the trend of small and intelligent of the device, this article proposes design of image capture and transmission system based on ARM S3C2440 microprocessor and embedded Linux operating system. This article describes how to build the hardware and software platform of the system, and focuses on the software design of image capture and transfer. The system is essentially a server that provides a monitoring function. It enables realtime video images displayed on the LCD, in addition, the users can view the captured video images over the network on the PC. System tests show that the system is stable, low cost, low power and portable, it can be applied to industrial control, automotive electronics and other fields.

Abstract:Image registration based on the feature extraction is widely used in the medical field. In order to apply the scaleinvariant feature transform algorithm into feature extraction and matching of vascular images, a suitable low contrast threshold is determined with the curve fitting method according to the vascular image characteristic, besides, in order to improve the speed and matching accuracy of the SIFT algorithm, conduct dimensionality reduction on the feature descriptors of SIFT algorithm. A method based upon the modulus comparison was used for feature points matching, find the matching points by comparing the relationship between the feature points vector modulus. The experimental results and data show that the improved algorithm has increased the performance in improving the matching rate and lower false matching rate,and it is important for the clinical treatment of vascular disease.

Abstract:With the increasing of SM3 password hash algorithm used at present stage, the execution speed and practical efficiency increasingly unable to meet the needs of processing large amount of data realtime of users. In order to further meet security needs of the era of big data, and improve the hardware efficiency of the SM3 algorithm, considering the feature of SM3 algorithm for efficient, we use hardware description language Verilog design FPGA hardware and integrated simulation using Xilinx software which test the design. Finally, we use the SM3 module in video data authentication on ARM and FPGA platform. Compared with the pure software which realize the same function, when clock is 100 MHz, throughput is increased more than 2 times, the execution efficiency of SM3 algorithm is greatly improved and the problem of realtime video authentication at the present stage is solved.

Abstract:Power factor correction（PFC）circuit are usually used to solve the harmonic pollution matter of power electronics. In highpower special applications, Threephase Boosttype power factor correction has a disadvantage of its high and narrow output voltage and not good for design of DC/DC. The paper studies on a more efficient threephase Bucktype PFC based on Swiss topology, analyses its operational principle and control strategy. Simulation verification by MATLAB/Simulink platform is carried on. A 10 kW experimental prototype using DSP for control is designed and developed, and experiments are carried on. Experimental results show that the circuit can achieve a stable 400 V voltage output, power factor approaches 1, efficiency over 97% at full load. It proves the feasibility and superiority of the circuit.

Abstract:High resolution time measurement system was implemented in a single FPGA based on time interpolation. On the basis of analyzing the principle of traditional digital counting method and its error, from the sight of error source, the fine time is the time difference between rising edge of the measured signal and next rising edge of counting clock, in order to measure the fine time accurately, we proposed a method that measures it with 4 interpolation clock signals, which have the same frequency and phase difference of 45 degrees in turn, estimating the fine time by latch clock state at rising edge of the signal to be measured. Meanwhile, a highspeed clock is used to measure the coarse time directly. The principle error of this method is discussed in detail. The experimental results show that this method can achieve a precision of 312.5 ps and the error less than 300 ps. The design has advantages of large measurement range, high accuracy, small size, and with less resource.

Abstract:This paper studies the astronomical orientation principle and several astronomical orientation method based on astronomical azimuth, and comparative analysis, the applicable scope of the different astronomical orientation method in this paper, the advantages and disadvantages of using LabVIEW graphical user interface language will be several astronomical orientation method in accuracy and scope of stellar selection and use of organic combination, realize the comprehensive application of five kinds of astronomical orientation method. Article gives the design idea, designs the program block diagram and calculating module, et al. The sofuare can input the observed data according to different methods, call the corresponding calculation module of fast solving azimuth and display, and save the raw data. The software has a good manmachine interactive, friendly interface, providing conveience for the relevant person who adopt astronomy orientation method to solve high precision azimath,achieving the expected design goal.

Abstract:In order to meet the demand of laboratory data test and record, a scheme of portable data recorder with high precision acquisition and dual core structureS3C2440 and MC9S12XS128, combined with the open source LINUX system is proposed. The hardware includes the operating system module and data acquisition card module. The application program using the multi thread and database technology has improved the operation efficiency of software. In the data communication part, the corresponding data acquisition card driver program and the communication protocol is designed to improve the stability of the system. Experimental results show that the recorder can collect and record multichannel data in 0.08 s interval with high storage speed, and expend the storage space with the SD card and USB removable storage deviceslarge storage capacity, and the standard voltage acquisition can reach the level of 0.02, which can meet the demand of laboratory.

Abstract:The precision positioning technology plays an important role in products precision machining, precision testing. A method of precision positioning with airbearing platform driven by linear motor is introduced in this paper. The working principle and designing plan of air bearing platform are described. The control model of the linear motor is given. And then a closedloop control is achieved with this new driver. Finally, platform location data were compared with LenScan position device, and the accuracy of the positioning platform is verified. The result shows that the platform structure is reliable and the system is stable. That the accuracy of X and Y directions is micrometer lever and meets the requirement. Now it is used in testing of geometry parameters of semiconductor devices, and the effect is good.

Abstract:For application of PT100 in industrial temperature measurement, the transfer function method based nonlinear correction is proposed and its superiority and practicality is verified. Multipoint temperature program is designed based on threewire PT100, using C8051F410 processor as the core, using the onchip ADC timeshared control, and multichannel temperature acquisition is realized. Practice showed that this scheme can increase the temperature measurement accuracy and efficiency of system development, and can be widely used in industrial control field.

Abstract:In order to reduce the error brought by human reading, an automatic reading system for pointer pressure gauge was designed, which was used for automatic verification of gauge. The system consisted of CMOS color camera, DOME light source and a computer. This system used DOME light source to reduce the interference of environment for the images of the gauge. Gauge images were transferred via USB data cable to a computer. Firstly, binarization was used to the images. Secondly, hough transformation was used to extract the centroid of the gauge. Thirdly, the pointer and tick marks were extracted by connected region labeling method. Finally, according to the position relationship between the pointer and the two neighbor tick marks and their values, the value of pointer indicated was computed. Through the evaluation of actual gauges, the system can figure out the value of gauges in a short time, and it greatly liberates the labor force, while it has improved the efficiency of gauge verification.

Abstract:The system uses PIC16F886 MCU as microcontroller and ultrasonic detection as core technology to design the medical ultrasonic oxygen flowmeter, within MPLAB software system.This system mainly consists of PIC MCU module, the signal switching circuit, the analog amplifier circuit,the filter circuit and the voltage comparison circuit. Oxygen is sent through a fixed pipeline, then the microcontroller send signals to the ultrasonic transducer, to measure the transit time of ultrasonic flow and temperature of oxygen.Based on least squares surface fitting method, we set up the oxygen concentration as a function of temperature and time, completing the measurement of gas flow.The measurement results show that the system is stable and reliable,and has high precision and very high value for engineering use.

Abstract:This paper presents a twodimensional lowsidelobe transmit beampattern synthesis for uniform linear Frequency Diverse Array (FDA) with convex optimization. As the uniform linear FDA array steering vector has two variables (i.e., azimuth angle and slant range), it is difficult to be solved by the convex optimization. We divide it into two singlevariable steering vectors with the Kronecker product, which depend on the angle and range, respectively. Next, they are formulated into two optimization problems and can be easily solved by the convex optimization. Finally, the two weight vectors are synthesized into a twovariable weighter with the Kronecker product. Simulation results show that the proposed method can achieve lowsidelobe twodimensional transmitted beampattern for FDA radar.

Abstract:Electrocardiography(ECG) plays a very important role in the diagnosis and treatment of heart disease, and R peak detection has become an important part of the ECG processing due to the Rwave amplitude with a large, easydetection feature. Correct detection of R peak is vital to the detection of heart rate and electrophysiological analysis. However, the ECG signal in the acquisition process will be subject to a certain degree of interference, such as frequency interference, baseline drift and other issues,so common R peak threshold algorithm can not detect lower baseline ECG waveform, resulting undetected. To solve this problem, this paper presents a R peak improved threshold extraction algorithm by setting thresholds and reexamining the mechanism for each cardiac cycle to improve the accuracy of the threshold algorithm. Simulation results show that the method is much simpler and more effective, and can realtime processing, which significantly improves the accuracy of the R peak detection and meets the requirements of clinical applications.

Abstract:Aiming at the problem of signal detection in low signaltonoise ratio in power line communication, the paper takes the most common modulation signal in power line communication— OFDM signal as detection object, and analyzes the favorable timefrequency analysis characteristics of wavelet packet transform. In the power line noise channel, according to the different wavelet packet decomposition characteristics of OFDM signal with the other single carrier signal, a detection method of OFDM signal based on wavelet packet transform is proposed by taking maximum value of wavelet packet decomposition coefficient norm two as detection characteristic quantity. The simulation results got by MATLAB show that this detection method can detect the OFDM signal in low signaltonoise ratio, and reflect advantages of the wavelet packet transform applying to the power line communication.

Abstract:This paper proposed a time domain measurement method of characteristic impedance based on TDR, because frequency domain measurement of the characteristic impedance is difficult to meet the needs of industrial production. This paper measured characteristic impedance of the standard circuit board using the TDR module Agilent54754A, and imported the text data of the experimental measurement from the oscilloscope to the computer as the measured data of circuit board characteristic impedance calculation. However, the measured data from the time domain measurement method is susceptible to time base jitter and the microwave reflection, the paper eliminated timebase jitter of data by PDF deconvolution method effectively, and removed the microwave reflection by selecting the best measurement zone in accordance with IPCTM650 regulations effectively, and integrated of two methods to process the experiment data. By transforming the voltage value into the impedance value, the results showed that data processing results are very close to the calibrated value of DUT.

Abstract:With the development of locationaware technology, the requirement of indoor localization becomes stronger. Indoor localization technology is rarely used under the linear environment so far. The SPMWKNN algorithm (weighted K nearest neighbor of short time path memory) is proposed to improve the efficiency of positioning in linear unstable environment. And in order to solve the problem of large variation of the wireless AP (access point), a wireless AP clustering mechanism is proposed which based on wireless AP correlation coefficient. The results of theoretical analysis and simulation show that the SPMWKNN algorithm aroused in this article effectively reduced the positioning time and improved the positioning accuracy in the linear unstable environment.

Abstract:Streaming media transmission `has widely used over wireless network. Because of the problem of conventional TFRC mechanism concerning incorrect packet loss rate, when it is applied to mobile congestion networks, the streaming media sever can not get the accurate information of the network condition and thus leading to excessive degrade the sending rate of data. Therefore, an important research issue arises, how to realize loss differentiation between congestion losses and wireless losses and accurate adjustment of network sending rate. Some major congress control protocols including TFRC, AIMD are briefly introduced. This paper propose a mechanism called MTFRC in the base of TFRC ,which appends loss differentiation algorithm. The simulation result shows that MTFRC improves network throughput and the network utilization and guarantee service quality of wireless network streaming media.

Abstract:In order to solve the problem of multipath fading and Doppler interference in the transmission of Police Digital Trunking (PDT) signal, we proposed new diversity reception technique for PDT signal. Firstly PDT system model is given, the fading channel conditions and signal structure characteristics are analyzed at the same time. On this basis, the structure of new base band diversity technique and the key algorithm of processing procedure are proposed. Along with theoretical analysis, software simulation results are presented. The simulation results show that the proposed postdetection diversity technique provided an obvious improve of bit error rate performance for communication systems. Because of the low system complexity and computation reduction, the presented diversity structure is suitable for using in practical engineering.

Abstract:Aiming at the lack of versatility method on management and monitoring in cluster system, a SNMP protocol based realtime monitoring system of cluster equipment is proposed. Functions such as equipment status checking, exception alarming and alarm information receiving are integrated into a general management mechanism which can effectively avoid the problem on inconsistency of the hardware interface in the cluster system. A realtime monitoring strategy combined of checking and interruption is proposed to reduce the complexity of the monitoring system design. The test results show that the timeliness and reliability of the system is desirable.

Abstract:C program design is a course with high practice. Experimental teaching is an important part of the course. The purpose is to let students in the experiment to actively practice, and to understand the essence of programming, to improve the ability to analyze and solve problems. Based on the summary of the existing common problems in the experiment teaching links of C language, on the proposed scheme is suitable for the current teaching environment and more C language experimental teaching reasonable improvement. The scheme has the important significance to improve the teaching effect to solve the problems in experiment teaching.