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On Three Kinds of Symmetries for Holonomic Nonconservative System

HE Guang, MEI Feng-xiang

2007, (7): 565-567.

Abstract(899)

Abstract:
For the same holonomic nonconservative system,the expression of the Lagrange equations under different generalized forces appear different.For different expressions of the equations,the Noether symmetry,the Lie symmetry and the form invariance can be changed.The result of this paper expresses that the gauge function in the Noether identity is changed,but the Noether conserved quantity is not changed.In this case,the Lie symmetry is not changed and the form invariance is changed. The condition under which the form invariance is changed is given.

Dynamic Response of Plates of Varied Thickness Subjected to Close Range Explosion

WU Yi-tian, ZHANG Qing-ming

2007, (7): 568-571.

Abstract(978)

Abstract:
With dimensional analysis on plates subjected to close range explosion,key factors influencing the dynamic response of plates are determined.The explosion process of the given TNT sphere is simulated by the flow-solid coupling algorithm applying the finite element analysis software LS-DYNA.Utilizing the priorities of numerical simulation,the thickness of the plates is varied so that the peak value of flexibility is linear with the thickness of the plates,however,the peak value of velocity is linear with the reciprocal thickness of the plates.

Calculating Dynamic Parameters in Elastic Thin Plates Under Blast Loading

FU Yue-sheng, ZHANG Qing-ming

2007, (7): 572-575.

Abstract(642)

Abstract:
With elastic theory and approximate calculation,the dynamic response of elastic thin plates with four edges simply supported under blast loading is analyzed.All mechanical quantities are solved based on differential equations of thin plates and characteristic of blast loading by theory.With dimensional analysis,30 cases have been calculated,and a reasonable model for engineering calculations built up.

Influences of Pulses upon Inter-Electrode Gaps and Electrolyte Flow Field in Ultra-Short Group Pulses Electrochemical Machining

FU Wei, ZHANG Zhi-jing, ZHANG Wei-min

2007, (7): 576-579.

Abstract(661)

Abstract:
Investigates influences of pulses on the bottom gap,the side gap and the electrolyte flow field in ultra-short group pulses(UGP) electrochemical machining.Models of the bottom gap and the side gap under group pulses and model of pressure wave under ultra-short pulses were presented.Based on the models the influence on the gaps and the pressure wave under UGP were discussed.The gaps become less under group pulses and the pressure wave become stronger with less gaps.The pressure wave becomes stronger under ultra-short pulses than that under high frequency pulses.In contrast with high frequency pulses electrochemical machining(ECM),the gaps between electrodes were less and the characteristics of the electrolyte flow field were improved in UGPECM,so the machining quality becomes improved.

Electronic Control Unit for High Pressure Common Rail System Diesel Engines

WANG Hong-rong, ZHANG You-tong, WANG Jun, DING Xiao-liang

2007, (7): 580-584.

Abstract(1172)

Abstract:
An electronic control unit(ECU) for high pressure common rail system diesel engines based on Motorola MPC555 is introduced.Using high performance microcontroller MPC555 and adopting schemes of modularization the hardware and fundamental software of the electronic controled unit(ECU) were set up.The hardware is made up of the micro controled unit(MCU),power,input and the output module.The software includes that of initialization,sampling,and outputting module.With this ECU,experiments on rail pressure control and fuel quality at different pulse and rail pressure were carried out,and do some MAP studies on start of injection(SOI) and rail pressure on engine test bench.Experimental results proved that this system can obtain quite fine effects in control.

Exploring the Characters of Electroencephalogram for Fatigued Drivers

PENG Jun-qiang, WU Ping-dong, YIN Gang

2007, (7): 585-589.

Abstract(1130)

Abstract:
To investigate the characters of the electroencephalogram(EEG) for fatigued drivers,the situation of fatigue driving was simulated using a car simulator,the EEG for the driver was recorded by an EEG recording instrument,and the EEG data and waves obtained.Methods of average power spectrum and correlation dimension were applied to analyze these data.Characters R and D in the EEG for the fatigued driver were found.The degree of fatigue of the driver can be estimated by the characters shown by the EEG.

Design the Description Function of Guidance System with Velocity Pursuit Guidance Law

SHEN Hao, XIA Qun-li, QI Zai-kang, WANG Juan-li

2007, (7): 590-593.

Abstract(1097)

Abstract:
For the nonlinear problem of simple guided munitions guidance and control system,description function is adopted to design the velocity autopilot including three types of nonlinear sections.At the same time,to obtain a better design result,based on means of description function combining the optimization program of nonlinear equations,a new method for nonlinear guidance and control system design is proposed.With the simulation results it is affirmed that the given method is correct.

Low Bit-Rate Video Coding Based on Gabor Dictionary

LIU Li-xiong, JIA Yun-de, LIAO Bin

2007, (7): 594-598.

Abstract(1087)

Abstract:
The computation complexity of the video coders based on matching pursuit is much higher,because of laboriously searching optimal atoms in a redundant dictionary.This paper proposes a video coding algorithm based on discreted Gabor dictionary,which incorporates an improved searching scheme using optimal timefrequency atoms,thus reduces the computation complexity of the original algorithm greatly.Experiment results show the algorithm can keep original coding efficiency and reduce the computation complexity efficiently.

Incentive Strategy Based on Credit Model in Hybrid P2P Network

GUAN Zhi-tao, CAO Yuan-da, ZHU Lie-huang, ZHANG Chang-you, FAN Xiu-mei

2007, (7): 599-603.

Abstract(1154)

Abstract:
In order to deal with free riding in P2P systems,an incentive model based on peer credit has been proposed.Each peer in this model is a credit entity.Through introducing reward method to the model,peers will allocate resources according to the credits of request peers to maximize their own credits.A backtracking algorithm has been suggested to solve the issue of maximizing credit rewards.To avoid inflation of the credit,attenuation method is introduced.The scheme on how to apply the credit model in hybrid P2P networks has also been presented in this work.The experimental results show that the model can effectively control free riding and improve efficiency of the system.

Rapid Reduction Algorithm Based on the Conditional Information Quantity

QI Li, LIU Yu-shu

2007, (7): 604-608.

Abstract(916)

Abstract:
To improve the efficiency of attribute reduction,a rapid reduction algorithm based on conditional information quantity is proposed.The concepts of information quantity based on partition and conditional information quantity based on partition are defined,and the theorems about the monotone of attribute significance、invariance of conditional information quantity based on partition are proven;Compared with other algorithms,this algorithm reduces the searching space of attributes and samples in each step.Experimental results showed that the rapid reduction algorithm is more efficient than the existing algorithms.

Method of Determining Avionics System's Weighting Coefficient Based on Rough Set Theory

ZHENG Xue-bing, LI Ping, SUN Jian-qiang, LI Kun

2007, (7): 609-612.

Abstract(539)

Abstract:
It is difficult to determine weighting coefficients of each parameters when evaluating the effectiveness of avionics systems.In this paper,rough set theory is applied to determine the significance of each parameter and then shift the significance of attribution to weighting coefficients.Based on the given method and combined with the subjective weighting method,a new synthetic weighting method is brought forward.After determining the weighting of ECM part of the third generation combat aircraft's avionics system,the result showed that the method given above overcomes shortcomings of traditional methods in determining weighing,possesses much more objectivity and improved the accuracy and efficiency of comprehensive evaluation.

3D Route Planning Algorithm for Long Range Missiles Based on A^*Algorithm

SONG Jian-mei, LI Kan

2007, (7): 613-617.

Abstract(921)

Abstract:
This paper proposes an approach of 3D route planning based on A* algorithm.This approach could directly search optimal route in 3D environment with route constrains,which discretizes the long range missile kinematics model and uses the overload of missile as control flow.The process of route planning not only integrates the maneuverability of missile,but also adequately uses the terrain information in terrain-avoiding and threat-avoiding.Simulation results demonstrated the method could obtain optimal route in 3D environment,which could adapt to overload constrains.

Study on Temperature Stability of Scale-Factor in Closed-Loop Fiber Optical Gyroscope

WU Yan-ji, HUANG Xian-lin

2007, (7): 618-620.

Abstract(969)

Abstract:
Based on closed-loop fiber optical gyroscopes,research work on the temperature stability of the scale-factor has been performed.The mathematical expression of the scale-factor has been established.The mechanism of temperature influence on the stability of scale-factor was analyzed.The coefficient of some parameters was given.An experiment on the temperature stability of the scale-factor has been performed in closed-loop fiber optical gyroscopes.It can be seen from the experimental results that the temperature sensitivity of the scale-factor has been changed from 8.08×10-4/℃ to 1.70×10-5/℃.

Wavelet-Based Principal Components Analysis Feature Extraction Method for Hyperspectral Images

NI Guo-qiang, SHEN Yuan-ting, XU Da-qi

2007, (7): 621-624.

Abstract(1216)

Abstract:
A new wavelet-based principal components analysis(PCA) feature extraction method is proposed for hyperspectral dimensionality reduction.Wavelet decomposition can reduce hyperspectral data in the spectral domain for each pixel.This may not only reduce the data volume,but also preserve the distinction among spectral signatures that is useful for most pixel-based classifiers.PCA can provide more local spatial information among neighborhood class pixels than wavelet decomposition.Experimental results show that the hybrid method can prove the effectiveness and accuracy in classifying the hyperspectral data.

Research on Software Aging Modeling and Software Rejuvenation

YAN Xue-mei, WANG Xiao-hua, CUI Xin-xin, ZHAO Jian-feng

2007, (7): 625-629.

Abstract(1023)

Abstract:
Software aging modeling prediction and software rejuvenation of Linux network server are studied.The momentum term and simulated annealing are added in the BP neural network to improve the convergence speed and overcome the local minimum value,by which the software aging is modeled and predicted.Meanwhile,a kind of software rejuvenation technique enhancing the reliability and usability of software system is put forward.Study results indicate that the method decreases the software disable rate and the unavailable time.

Joint 2-D Angular and Frequency Estimation for Uniform Circular Array

XIE Min, FU Tuo, GAO Mei-guo

2007, (7): 630-635.

Abstract(1152)

Abstract:
Investigates the problems of joint 2-D angular and frequency estimation based on uniform circular array(UCA).Based on the stacking of data matrix,real-processing of signal subspace,complex shift invariance equation and joint eigenvalue estimation,an algorithm is presented to solve this problem and handle the estimation jointly.It is shown that finally this problem turns to the estimation of the real joint eigenvalues of three real matrices and solve the joint eigenvalue estimation by a recently proposed simultaneous diagonalization algorithm.The advantages of the algorithm are attained,i.e.strong identifiability results and autopairing capacity.Theoretical analysis and simulation prove the effectivity of the algorithm.

Channel Estimation in MIMO-OFDM Systems by Tracking the Delay-Subspace

JIAO Hui-ying, AN Jian-ping

2007, (7): 636-640.

Abstract(1041)

Abstract:
A time domain channel estimation method in MIMO-OFDM systems by tracking the delay-subspace is proposed.The time impulse response is estimated by transmitting known pilot symbols,and the estimation performance is improved by the Givens rotation based delay-subspace tracking and amplitudes tracking based on the LMS filtering.Simulations proved that the time domain channel estimation by tracking the delay-subspace can track faster fading channels,and is more accurate and yet of low complexity.

Preparation and Photocatalytic Kinetics of Nano-ZnO Powders by Precipitation Stripping Method

XU Hang, ZHANG Dong-xiang, XU Wen-guo

2007, (7): 641-645.

Abstract(1019)

Abstract:
Ultra-fine zinc oxalate powders were prepared through precipitation stripping method with Bis(2-ethylhexyl)phosphate(HDEHP) diluted by tetrachloride carbon as an extractant,and oxalic acid ethanol aqueous solution as a re-extractant and precipitator.Zinc oxide powders were obtained by decomposing zinc oxalate powders at 450 ℃.The prepared zinc oxide powders were characterized by TEM,SEM,TG,XRD and FT-IR.The photocatalytic performance of methylene blue by zinc oxide was studied based on the Langmuir model and photo-layer model.The results showed that some zinc oxide powders were micro-multipore materials with hexagonal crystal and the particle size was around 32 nm.The photocatalytic process was the control step in chemical reaction.The photo catalytic process followed the pseudo-first order kinetics and ·OH concentration inside the photo-layer in different reaction condition were calculated according to the photo-layer model.

Optimized Conditions of 1-Phenylpropanol Separation on the New Chiral Stationary Phase of Peptide Bonding β-Cyclodextrin

LUO Ai-qin, QIAN Wei, WANG Fu-ming, LI Yan, SUN Liquan, GENG Li-na

2007, (7): 646-649.

Abstract(1070)

Abstract:
A new derivate of β-cyclodextrin with peptides was prepared,where the peptides were obtained from the enzymolysis of bovine serum albumin(BSA) in the presence of trypsin.The derivate was bonded with silica gel to give a novel chiral stationary phase for high performance liquid chromatography(HPLC).The chiral separations of(±)1-phenylpropanol was investigated using an re-phase RP-HPLC system with this column.Several important HPLC conditions were studied including variability of gradient time of pH value of phosphate buffer,ionic intensity,and mobile phase velocity.The chiral recogniztion mechanism and the repetition on chiral separate of 1-phenyl-propanol on the new stationary phase were probed.Experiments shown that the best condition of 1-phenylpropanol on the new chiral stationary phase(CSP) is mobile phase,60 mmol/L phosphate,gradient pH buffer,1 min pH 5.6,10 m in pH 6.4,flow rate,0.5 mL/m in.

Selection of Game Coalition Based on Fuzzy Group Decision-Making Theory

PANG Jin-hui, ZHANG Qiang

2007, (7): 650-654.

Abstract(893)

Abstract:
Under fuzzy game environment,the problem of how to choose likely game persons to form an advantage alliance was considered.The Bernardo multi-criteria group decision-making method was extended by means of the uncertain theory.Then the extended method was applied in dealing with the problems of preference coalition selection with fuzzy resource constrains.The fuzzy chance-constrained model of coalition selection as well as its solving approach was put forward.Furthermore,an effective fuzzy group decision-making technique of preference coalition selection is proposed.

A New Executive Stock Option Pricing Model

ZHANG Chen-yu, XIAO Shu-fang, LI Xuan

2007, (7): 655-658.

Abstract(836)

Abstract:
Two problems of application of Standard Options pricing models in the practice of executive incentive plans were argued.The paper analyzes how asian options and indexed options pricing models deal with above two problems and proposes to design a new incentive option model,called A-I model,which combines both of the asian options and indexed options'characters.And based on the no-arbitrage method,risk-neutral measure,ITO theorem and first order and second order moment method,its pricing model was derived.Numerical results show that this model has better incentive effects than others.

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