Editor in chief:Prof. Sun Shenghe
Inauguration:1980
ISSN:1002-7300
CN:11-2175/TN
Domestic postal code:2-369
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2016, 39(9):1-3.
Abstract:Energy forecasting is important in enterprise management, In order to solve the problems existing in the system of power energy forecasting, To use a simple grey forecasting model GM (1, 1) was simulated firstly,Through Matlab simulation software,Then according to the enterprise for the first nine months of the power consumption of data to predict three months after the power consumption of data. Draw the simulation curve. lastly,Using the improved gray model PGM (1, 1), Comparing the simulation results curve found improved prediction algorithm model has a smaller average relative error,PGM (1, 1) algorithm to overcome the GM (1, 1) grey model mutation of data in a short period of time, Make the results of the prediction model is more close to the enterprise actual power consumption data.
Yang Guang , Ge Hongjuan , Chen Si
2016, 39(9):4-7.
Abstract:The advantage of 18pulse autotransformer rectifier unit(ATRU) is low input current harmonic content,output voltage ripple and transformer equivalent capacity.But the output voltage can not satisfy the requirements of the aviation low voltage DC system.This paper based on 18pulse autotransformer rectifier,designed buck circuit,kept the advantage of original performance and achieved the 28 V DC output.The paper introduced the phase shifting principle and winding structure of 18pulse autotransformer rectifier firstly,then analysed the output voltage characteristic.According to the need of reducing voltage introduced the buck circuit and it’s control circuit.In addition,designed parameters of main circuit and control circuit.Finally,the system was established and analysed in Saber simulation environment, verified the system had a good input and output performance.
2016, 39(9):8-11.
Abstract:This paper focuses on the position characteristic test of STEP SA1400 industrial robot based on GB/T 126422013“Industrial robotsperformance criteria and related test methods” by using CompuGauge testing system from Dynalog company. Firstly ensure this testing on the foundation laid by GB/T 126422013 “Manipulating industrial robotsperformance criteria and related test methods”. Analyze the primary error of the test after the test finish and compute all parts of uncertainty of the test course. Finally evaluate the position characteristic uncertainty.
Hou Tiantian , Hao Runke , Yang Wenhuan , Liu Junfeng
2016, 39(9):12-15.
Abstract:The threephase hybrid stepping motor (THBSM) is equivalent to the permanent magnet synchronous motor(PMSM) running at low speed, which can be controlled by the advanced control method of synchronous motor. Based on the theory of auto disturbance rejection controller (ADRC), a novel method of sensorless vector control for THBSM is proposed, which transforms THBSM under the threephase static coordinate system to the twophase rotating coordinate system. The action of the speed and the d axis current on the q axis current is considered as the disturbance of the torque current loop. Using MATLAB/Simulink to build the simulation model, the simulation results demonstrate the effectiveness of the proposed method.
Wang Yang , Ye Zhihui , Feng Qi , Guo Xiaoqing
2016, 39(9):16-19.
Abstract:Indoor positioning is not a popular technology, although it is widely used in our daily life. In order to achieve accurate positioning in the indoor complex environment, a light, convenient and offline WiFi positioning system is designed. The system based on Android platform is developed, which is based on the improved RSSI algorithm added by after verification method to avoid the excessive migration of the position coordinates. Compared with the conventional WiFi positioning system, the database of the system is integrated in the equipment to avoid the positioning delay and failure caused by the connection of the database and the communication inconvenience. After testing, the system can work stably and control the range of error within 3 meters in the corridor room scene, which can meet the requirement of indoor mobile positioning.
2016, 39(9):20-25.
Abstract:According to the structure、output signal characteristics and working demands of 320×256 longwave area array infrared detector, a focal plane circuit is introduced. The designed circuit consists of bias voltage engender circuit, signal preprocessing circuit and sequence driving circuit. The bias voltage engender circuit not only achieves the design of fixed bias voltages, but also achieves adjustable bias voltage’s design, which enhances the flexibility of this circuit. In this paper, the designed circuit is simulated and tested after the detailed introduction of every part’s designing scheme and completed the plating of the circuit. Simulation and test results show that the circuit could drive this infrared detector to work normally and could achieve the output analog signal’s preprocessing. This design idea of focal plane circuit for 320×256 longwave area array infrared detector is feasible and meaningful.
Qiu Ling , Yao Zhendong , Liu Yuyan
2016, 39(9):26-30.
Abstract:The microstrip antenna has the advantages of small size, light weight and low profile, can be designed as a radio altimeter antenna. The rectangular patches are composed of broadband and high gain antenna array, using the way of arraying. The increasing of the substrate thickness expand band and multi section impedance obtain large gains. This structure is applied to design the four element microstrip antenna array. The center frequency is 4.3 GHz, the bandwidth is more than 200 MHz. the method of equal amplitude parallel feed is adopted. According to HFSS the simulation results show that the maximum gain is 11.3 dB, the VSWR is less than 2, and the 3 dB beam width is about 46 degrees. The bandwidth is expanded to4.08~4.52 GHz, and the maximum gain is 10.33 dB. The structure of the antenna array is simple, and its good characteristics can be applied to the small aircraft altimeter system.
He Chenggong , Deng Lianwen , He Jun
2016, 39(9):31-33.
Abstract:In the electrified railway sections,the offline bow net arc caused by pantographcatenary detachment is a main EMI noise to electrifed railways. The paper discussed the mechanism of EMI noise production through the theoretical analysis of the basic form of the gas discharge at atmospheric pressure. Then the dissertation further elaborated that electron swarm oscillate,caused by near cathode effect of AC arc is the radiation source based on streamer theory. According to the electron swarm oscillate,a dipole antennas model was presented in the paper. Moreover,HFSS15 was used to simulate radiation characteristics of pantograph contact loss electric arc. The results are consistent with the experimental results reported in the literature.
2016, 39(9):34-39.
Abstract:Manmade targets detection is a crucial function of synthetic aperture radar (SAR) automatic targets recognition (ATR) systems. At present, there exist sort of limited methods which are applicable to complex background. To treat this case, a method based on the intrinsic dimension of multiaspect angle image samples is proposed. This method doesn’t count on intensity of the image, whereas it estimates the intrinsic dimension of images samples of the region of interest (ROI) in high dimensional space, which are obtained from different aspect angles. The measurement of artificiality and naturalness is performed with the intrinsic dimension of ROI. In this way manmade targets are detected. The real data from Gotcha project are adopted to compare our method with that of fractal dimension to detect manmade targets. The experiment result shows that intrinsic dimension has a merit that it doesn’t count on image intensity and it performs better than the fractal dimension method in depicting the shape of targets.
Meng Xiangli , Hou Xiaomin , Lian Xin
2016, 39(9):40-44.
Abstract:The single pulse mode of IRUWB can affect the single pulse mode to the power spectral density of the transmitted signal, the single pulse mode selection should follow the principles that high spectrum efficiently, interference suppression flexible pulse generator easy. For information on data modulation are mainly based on the amplitude modulation (PAM) and based on delayed phase modulation (PPM), when the main multiple access technologies hop (TH) spread spectrum modulation, direct sequence (DS) spread spectrum modulation, most the main two basic modulation is THPPM and DSPAM. Gaussian pulse, the pulse waveform modulation, timehopping technology, direct spread spectrum technology together to form a new hybrid modulation DSTHPSM modulation.
Zeng Youbing , Hong Jun , Wang Yu
2016, 39(9):45-50.
Abstract:Interferometric parameters calibration is of great significance to get high precision digital elevation model for airborne InSAR system. The physical baseline is one of the important parameters for interferometric calibration. In squinted geometry, the interferometric baseline is not equal to the physical baseline, and it’s influenced by aircraft attitude. The parameter that the traditional sensitivity equations which are derived by differentiating the elevation equation with respect to the interferometric baseline parameter calibrate is the effective baseline, instead of the real physical baseline. Aiming at this problem, this paper analysises the effective baseline in squinted geometry, and formulates the effective interference baseline with the physical baseline and the aircraft attitude, then proposes a method to calibrate the real physical baseline. Finally, A calibration experiment has been performed with real data acquired by the Xband airborne InSAR of the Institute of Electronics, Chinese Academy of Sciences to verify the method.
Shi Cangsong , Huang Guangming
2016, 39(9):51-55.
Abstract:By moving the linear spectrum principle, we proposed a 100~1 000 MHz sweep source circuit design. Quadrature signal with the quadrature local oscillator signal of the program orthogonal single sideband modulation method based on the DDS chip are generated by multiplying the sum output signal and local oscillator signal one sideband is suppressed, another sideband signal is the signal obtained by direct conversion will be retained. Study tests show unwanted sideband and the carrier signal of the circuit were inhibited by about -40 dBm, and the circuit also has a higher frequency accuracy and frequency range, not only retains the DDS frequency resolution and excellent frequency agility features but also achieved a wide band sweep function.
Wang Jia , Yao Jun , Wang Lei , Zhang Lulu
2016, 39(9):56-59.
Abstract:Based on the principle of time difference method for flow rate measurement and the principle of thermal resistance for temperature measurement, a kind of calibration device for transducer of ultrasonic heat meter is studied in the paper. The dry calibration device consists of the flow simulation module, temperature simulation module, a microprocessor unit and host computer. The implementation of flow simulation module and temperature difference simulation module is described in detail, as well as the function of the microprocessor. Finally, the comparison result between actual flow calibration data and the dry calibration data from the calibration device in this paper show that the calibration device for transducer of ultrasonic heat meter can effectively implement the function test of ultrasonic heat meter.
Fan Zhenfeng , Huang Ling , Liu Dunge , Xu Xin , Zhang Xiaojuan , Fang Guangyou
2016, 39(9):60-63.
Abstract:Airborne magnetometry has a long and fruitful history in many applications. The acquired data are usually contaminated by noises originated from a variety of sources, which migrates the effectiveness of the system on detecting magnetic targets. In this paper, a large loop with DC current is designed, serving as a manmade magnetic target. Then, an experiment for helicopterborne magnetometry is performed to measure the induced magnetic field at different elevations. The acquired data after denoising can be used to calibrate the airborne magnetometry system which will be further applied to aeromagnetic measurement or magnetic targets detection. The data processed result shows a good performance for the system because it is capable of detecting a magnetic target of a few nT at a long distance.
Lu Mingming , Zhang Hui , Shen Qinghong
2016, 39(9):69-72.
Abstract:Audio fingerprint is a digital digest of the signal which represents the most significant characteristics and is widely used in identification、security validation and integrity verification of audio signal. This paper presents a method of generating audio fingerprint based on the power spectrum characteristics of the signal. After calculating STFT of the input sample and extracting the peak of the power spectrum, we use the space structure of the peaks as input of the hash function of the audio fingerprint algorithm. As experiment shows, it could achieve a recognition accuracy of over 95% when the audio sample lasts more than 2 s and shows good resistance to AWGN noise. It is easy to implement、robust enough and exhibits fast and accurate identification ability.
Wu Jianbin , Fei Xiaoxiao , Wang Nianfeng
2016, 39(9):73-76.
Abstract:In order to improve the security of OpenVPN technology, this paper introduces the VPN technology,based on SSL protocol,and then find the existing password algorithm of weak strength of the technology,put forward the method of high strength encryption algorithm which represented by ZUC has been internationally recognized to replace the original weak strength algorithm in OpenVPN,realised the call of ZUC algorithm by writing a custom engine including ZUC algorithm, and has the characteristics of low cost and high security. After the Sniffer Pro capture test and TCP / UDP debugging assistant data communications test, the results show that, data communication between the client and the server can be encrypted by zuc algorithm in order to achieve the purpose of communication security, and high strength encryption algorithm of the system, to a great extent, meet the such as government, military and financial security requirements in areas of higher demand, has a strong practical value.
2016, 39(9):82-86.
Abstract:In order to ensure the realtime performance of vehicle steering system, the transmission delay which is an important factor of clock synchronization is researched in this paper,especially uncertainty of transmission delay.With the nodes send message with each other,action point of local node could get corresponding timestamp message which is sent by the load segment of synchronous message,and the algorithm could be concluded with the timestamp and the corresponding FlexRay nodes.This algorithm could be applied to the startup of distributed system, with transmission of synchronization message,transmission delay and decoding consumption could be calculated,then configuring node, and the clock synchronization accuracy of the system could be improved and the bandwidth resources also couldn’t be wasted. According to the simulation of FlexRay steeringbywire system which the algorithm has been embedded,after correction of transmission delay,the asynchronous nodes could be adjusted effectively.the algorithm improve the overall realtime and reliability,which is of certain significance to the development of automobile technology.
2016, 39(9):91-95.
Abstract:This paper concerned with the issue of image segmentation for intensity inhomogeneity, and a novel double regional evolution (DRE) based on level set method is proposed for image segmentation. The proposed DRE method introduces the local regional control term and the rectangle initialization contour, which can able to quickly segments uneven grayscale images and accelerates the curve evolution rate. In order to reduce the noises effects for image, the image segmentation method adopts Gaussian filter operator and convolution calculation. In particularly, DRE method develops a new potential penalty function as regularization term, which is embedded into the level set evolution equations to increases the constrained conditions based on the gradient flow conditions. Due to the potential function promotes the image contour evolutions with bilaterally extended, during the evolution, it is improved the image contours segment efficiency and numerical accuracy. Compared with the recent proposed methods based on level set, there are some superiorities of DRC method for image segmentation.
Su Hai , Zhang Qunying , Ye Shengbo , Zhang Xiaojuan , Fang Guangyou
2016, 39(9):96-101.
Abstract:In the pseudo random coded ultrawideband radar system, realtime pulse compression of the raw echo signal is the first and key step for signal processing. A new method of fast and realtime pulse compression is proposed in this paper as the sampling rata of ultrawideband radar is high and the amount of echo data is large, but the processing speed of DSP chips and microprocessors is limited. In order to achieve fast and realtime pulse compression, this method is based on the crosscorrelation algorithm on time domain by calling the DSPs embedded in FPGA in pipeline mode to parallel computing. The simulation and experimental results show that the proposed method can well realize the pulse compression for ultrawideband radar.
Lin Tong , Liu Hui , Ji Yicai , Fang Guangyou
2016, 39(9):102-107.
Abstract:Optically pumped cesium vapor magnetometer generates larmor frequency and needs to get magnetic field values by translation of measured frequency. The precision of frequency measurement is directly related to the accuracy of measured magnetic field values. This paper presents a frequency measurement method for optically pumped cesium vapor magnetometer based on FPGA carry chain. Firstly, using the adder to connect FPGA special carry line into a carry chain, and then based on the principle of time interpolation to achieve the measurement of larmor frequency. Compared with other frequency measurement methods, the proposed method can be realized only by the FPGA programming, and requires no additional hardware cost. The test result of the prototype shows that the system is feasible and the measurement accuracy is high. Thus achieving frequency measurement of optically pumped cesium vapor magnetometer with low cost and high flexibility.
2016, 39(9):108-113.
Abstract:Due to the low precision and efficiency of traditional measuring methods for largescale objects in aerospace field, it is necessary to develop a 3D vision measuring equipment with fullview and high precision. The fullview image information processing system is the key of the equipment. In order to deal with the large measurement image information timely and effectively, research on highspeed parallel image processing technology, design a parallel image processing scheme based on double multicore DSP and FPGA and implement the hardware circuit. Put forward the software realization method of parallel processing. Apply the image processing algorithm to the hardware system and then the system is verified by experiment. For a large image of 8 000×10 000, the result proves that the processing speed of single image within 0.15 s.
2016, 39(9):114-117.
Abstract:With the development of Internet of things technology, Android mobile phone with its unique openness advantage makes our life become more quick and convenient. In this paper the design of smart car was completed on the mobile phone platform with the help of bluetooth technology, which provided a new idea of wireless remote control smart car for us. The function of the smart car was first introduced, and then the hardware and software design of the system were elaborated. The mobile phone bluetooth and bluetooth module HC06 of the singlechip were respectively used as the client and the server. The client implemented JAVA programming processing in App Inventor, while the server was written in C language program for MCU control in order to carry on serial communication. The final results showed that: the car could receive signals from mobile phone and could flexibly implement the realtime control function of forward,backward, turning left, turning right, and stop.
Wang Ning , Yin Xianhua , Liu Mingyuan
2016, 39(9):118-122.
Abstract:In accordance with the characteristics of smart home on security, humanity and intelligence, a wireless monitoring system for smart home based on Android was proposed. The ARM microprocessor CortexA8 was designed as the hardware platform. Android4.0.3 operating system, SQLite database and Socket were adopted as the software platform. A smart home wireless monitoring system was constructed based on ZigBee technology. The monitoring device realized realtime monitoring of home environment parameters, and the server could store the parameters. Android client could access the server data and control home appliances by wireless way. The test results show that the server can store data quickly and stably, both of the local client and mobile client can achieve intelligent home monitoring. The system has a better practical value, which is more functional, more convenient and userfriendly, and adequate to meet user’s demands.
Liu Yuan , Wu Yanwen , Lu Jiahui , Xiong Yaqing , Yang kai , Liu Peize
2016, 39(9):123-127.
Abstract:Safety for the old is a matter of considerable interest. It is a design of intelligent walking stick system which can realize automatic alarm based on Internet of things. Data sampling and data processing are included in the walking stick terminal. The system takes good use of which ADXL345 acceleration sensor has the advantage in measuring angles with high precision and SIM908 integrates GPS and GSM to get accurate condition of the old, then decide and take actions. It overcomes the shortage that related domestic products currently can only ask for help manually. Experiment proofs the system can get positions, detect falling down,communication and alarm automatically. It is a method to providing security for the elderly.
2016, 39(9):128-132.
Abstract:It has gained the attention of researchers both at home and abroad to use remote rehabilitation robotic technology for stroke patients’ rehabilitation treatment,and that has become a hotspot in research of rehabilitation. For the need of medical rehabilitation for the stroke and hands injured patients, a onetomany remote hand function rehabilitation training robotic system based on the typical model of C/S is designed. It allowed doctors to remote control the machine via AV and evaluate according to the training parameters, thus make more scientific and reasonable rehabilitation training plan to help the stroke patients or hand disabled persons at home or community hospital.It has been proved that the system has a promoting effect on hand function recovery, and it can assist doctors in the rehabilitation training.
Qian Chenghui , Bin Kangcheng , Zhang Hanliang , Song Jibin
2016, 39(9):133-136.
Abstract:Based on three demodulations, this smart voltmeter is capable of the automatic measurement of peak value, effective value and average value of direct voltage and any periodic AC signals. By applying excluding extreme value averaging filter algorithm, the voltmeter provides better resistance to burrs and low amplitude random noise, which as a result, improved the systematic accuracy. The voltmeter input frequency is ranging from 1 Hz to 1 MHz, with an amplitude range from 0.1 V to 10 V and a relative error less than ±1%. With its tiny size and light weight, this voltmeter drastically promoted the function upgrade of digital multimeter products on the market.
Li Chunyu , Huang Yuping , Zheng Zaiping , Wang Yichuan
2016, 39(9):137-140.
Abstract:Free piston stirling engine linear motor power generation system earns widespread attracts for the possession of properties as highefficiency, long term on track and broad application resource. Position detection plays an important part on the Free Piston Stirling Engine Linear Motor Power Generation System, from which the rationality and stability of the motor design working system can be analyzed. To acquire the dynamic procedure from the starting powerdriven status to the power generating status of Free Piston Stirling Engine Linear Motor Power Generation System, and to decrease the system volume and improve the leakproofness, a pressure wave testing method based on sensorless position detection was designed. This method makes use of a new pressure wave sensor, accompanied with appropriate powersupply, conditioning and acquisition circuit, it detects the position of the engine’s active cell in real time, thus to realize the control of the power generating system.
2016, 39(9):141-144.
Abstract:We innovatively synthesize multifunctional copolymers to change the surface polarity of PbS quantum dots. The original oleylamine ligands are replaced by carboxyl terminus, as carboxylcontaining ligands have stronger binding affinity towards the PbS quantum dots surface than aminebased ligands. After ligand exchange, PbS quantum dots are transferred from nonpolar solvent to polar solvent. The new mothod could keep the fluorescence efficiency and stability of PbS quantum dots in polar solvent better. Alcoholic solution of PbS quantum dots are coated on the surface of the tapered singlemode fiber by grow method to make fiber amplifier. Since fluorinecontaining polymers can affect the gain characteristics of the optical fiber amplifier, we study the influence of polymers with different fluorine content on the signal gain. The result shows that the signal gain are higher with increasing the fluorine content of the polymer.
2016, 39(9):145-148.
Abstract:This paper introduce an automatic temperature compensation system based on the PIC for high speed small form pluggable(SFP) optical transceiver module. Comparing with conventional design, the module includes a microcomputer PIC,it can monitor a series of parameters of optical transceiver in real time by programming. Through this system,the SFP optical transceiver module can complete driver chip’s reading and writing rapidly. To ensure that the module can work in the best condition under the different temperature. The experimental results show that all parameters of SFP are regular as the change of temperature.
Guo Zhanchao , Qin Yurong , Long An
2016, 39(9):149-152.
Abstract:For the current research on the lightinduced brain electrical signal of spectral that focused on experimental test, due to lack of a theoretical model which led to the conclusion diversification. To solve this problem, proposed that combine computational model and electrophysiological knowledge, built visual pathway model, simulated the signals of visual pathway cortex pyramidal cells at different frequencies of light stimuli, then analysis of the corresponding spectral energy distribution, finally collected the same experimental conditions, different subjects of brain electrical signals, compared with the simulation results to verify the validity of the model. The research results show that the low frequency stimulation signals (2, 5, 10 Hz) are more likely to induce rhythm synchronization response, spectrum energy is mainly focused on the fundamental wave and low harmonics, and caused by high frequency stimulation (30 Hz) of the response which spectrum energy mainly concentrated in the low frequency.
Gao Lixin , Zhou Weilin , Chen Tuan , Li Yanan
2016, 39(9):153-157.
Abstract:To achieve excellent linearity, high resolution and superior stability of Inclinometer Probe, this paper designed a signal acquisition and processing circuit which used STM32 as MCU for Inclinometer Probe, while the silicon flextwre accelerometer was used as a sensor. In this article, hardware design and software design were introduced in detail. Signal conditioning and AD conversion were implemented for the acceleration of gravity signal from accelerometer. After calculation of the inclination, digital filtering, temperature compensation were used for the transformed data, DA conversion made the digital signal to be the value of inclination which was a voltage. In experiments,the nonlinearity error is less than 0.001°, resolution reaches to 0.000 3° and maximum temperature drift is 0.010 9° about the measured angle value of the Inclinometer Probe.
Luo Fei , Wang Yanfei , Niu Xiaoli , Cao Ge
2016, 39(9):165-171.
Abstract:Based on the analysis of existing dechirp approaches, this article provides a modified high efficient digital dechirp approach on synthetic aperture radar(SAR). Under the premise that the pulse width is longer than the main irradiation area, sampling rate lower than the bandwidth of transmitted signal can be applied to receive the echo signal in range with dechirp. The dechirped signal is then compressed after FFT without aliasing. The method highly reduces the sampling rate, thereby decreases the requirement on ADC devices and then reduces the pressure upon following signal processing and storage. It provides an effective way to realize the miniaturization of SAR. The article puts forward theoretical analysis and mathematical derivations of this improved digital dechirp approach, and the accuracy and effectiveness of the method have been verified by the formulation and simulation.
Meng Xiangzhong , Wang Zhenqi , Lin Cunhai
2016, 39(9):172-175.
Abstract:Based on the theory of fuzzy diagnostic and configuration software,We designed vibration monitoring and diagnosis system based on fuzzy diagnosis theory.The system collects vibration data based on s7200 and EM231 analog acquisition module,and use the RS485 to establish communication with the configuration software.And the data stored in its database.We use fuzzy theory of diagnosis to deal with the vibration fault.And the vibration hoist is realtime displayed on the MCGS configuration software and vibrated abnormal situation alarm.It realized the mine hoist vibration security status of realtime monitoring and alarm.The system resolve manual inspection errors and lack of continuity issues, improving system monitoring accuracy.
2016, 39(9):176-181.
Abstract:A transient line selection method in resonant earthed distribution network based on EEMD is proposed.Extract 1/4 period transient zero sequence current of each line as the data window length, decompose the 1/4 period transient zero sequence current with EEMD into a finite number of intrinsic mode function components IMF and a remaining components r.Do correlation analysis of the IMF component of each line with the original signal, select three IMF component as the characteristic IMF component which their correlation coefficient is the first biggest,calculate characteristic IMF components and residual energy as the inherent mode energy of a line.Calculate intrinsic mode energy weighting coefficient of each line,select the fault line by comparing the size of the energy weighting coefficient. In order to determine the bus fault, choose the first three lines which their energy weighting factor are biggest for further comparison. The method use the transient signal, not influenced by arc suppression coil, applying to the neutral point grounding and resonant grounding distribution network at the same time,can also applying to high resistance grounding fault and small Angle ground fault.MATLAB simulation verify the validity of the method.
2016, 39(9):182-186.
Abstract:BP neural network is a neural network with a wide range of applications, but there are obvious defects: slow convergence and easy to fall into local minima. The genetic algorithm has the ability to search the global optimal solution with a good prediction model. In order to improve the accuracy in the prediction of BP neural network, a prediction method of genetic algorithm optimization based on BP neural network is proposed. Using genetic algorithm to optimize BP neural network weights and thresholds, and then training the BP neural network prediction model to obtain the optimal solution, and the prediction method is applied to the Buck output voltage average validated. The simulation results show that the improved method has good nonlinear fitting capability and higher the accuracy of prediction.
2016, 39(9):187-191.
Abstract:Wireless sensor network (WSN) communication channel is designed to balance the inter symbol interference between wireless sensor nodes, and improve the quality of communication. A WSN communication channel equalization algorithm based on direct sequence spread spectrum is proposed. The WSN channel model is designed. In order to reduce the steadystate error of the output of the channel, the time reversal mirror is used as the matched filtering method, and the inter symbol interference filter is designed. The channel equalization of WSN communication is realized by the direct sequence spread spectrum method. Simulation results show that using the algorithm for WSN communication channel equalization design and emission signals along each path arrival signal components of the receiver to get accurate separation, signal multipath components are no bit errors at the receiver, communication channel equalization effect better and reduce the communication bit error rate, to improve the quality of communication of WSN, shows a good application value.
Editor in chief:Prof. Sun Shenghe
Inauguration:1980
ISSN:1002-7300
CN:11-2175/TN
Domestic postal code:2-369