INFORMATION THEORY COMBINATION FOR ERROR ANALYSIS OF. SAMPLING-QUANTIZATION FOR DIGITAL MEASUREMENT SYSTEMS

This paper presents a new error analysis method based on the information theory. The analyse results of error of a digital measurement system will be illustrated more reasonably. This method is defined information theory combination, it will overcome the unintention between the uncertainty and the standard error of measuring results by traditional error analysis. On the basis of error spectrum analysis of sampling and quantization, an optimum digital filtering method is also presented in this paper. Simulation and testing show that the method is more resultful.     

Error Analysis and Modification of Virtual Instrument System

The errors of each parts of virtual instrument system, which are produced in the signals transfer process, are introduced. These errors include sensor error, signal conditioning error, data acquisition error and data dealing error, etc. The main error can be found by analyzing the influence of these errors on different virtual instrument system. The methods of errors modification are also discussed. It's an effective method that modifying system errors, especially nonlinear errors, by software. At last, as a good example, the error analysis and modification of Virtual Noise Analysis Instrument is given.     

Digital Filtering with Zero Phase Error

Aiming at the problem of phase error caused by normal filters in signal processing , summarizes the important meaning of digital filtering with zero phase error. Puts forward RRF Filtering which is a new way to realize digital filtering with zero phase error through reversing the time serials of the signal. Another way to realize digital filtering with zero phase error is suggested through reversing the time serials of normal filter. Testifies the way to realize digital filtering with zero phase error. Points out how to design the digital filter with zero phase frequency peculiarity. Solves the problem of phase error in DSP.     

元动作装配单元误差传递模型及有效路径求解方法

在对机械产品进行"功能-运动-动作"结构化分解的基础上,将影响元动作装配单元装配精度的误差源分为零部件的形状误差、位置误差、装配位置误差和运动误差等四类误差源。引入误差链接模型作为元动作装配单元误差关联关系的基本封装单元,构建结构化误差关联模型——链接网络和链接矩阵,形象描述误差间的耦合嵌套关系。提出基于误差链接模型的装配误差传递路径求解方法,用老鼠迷宫算法搜索所有可能的误差传递路径,以装配精度最高作为判别依据,得到各误差分量的有效传递路径。以蜗杆转动元动作装配单元蜗杆轴线平行度误差有效传递路径为目标,对上述方法进行验证,结果表明该方法能够高效地搜索到所有误差传递路径,并快速获得有效传递路径。该方法的提出为整机装配过程质量预测与控制提供了理论依据。     

Statistical Model on the Time and Time Difference Error of Arrival in TDOA Location Estimation

Additional time delay of arrival resulted from non-line of sight(NLOS)propagation and muti-path effect in(cellular) environment is the dominant factor resulting in TDOA location error,study on the statistical property of TDOA error is useful for improving the accuracy of TDOA location.Based on the exponential distribution property of NLOS propagation delay,and considering the system error resulted from the signal detection,the authors establish a statistical model of arrival time and a model of TDOA error distribution by statistics when non-light of sight and multi-path propagation exist.The models reflect the statistical property of arrival time and TDOA error in cell network,the simulation shows that the proposed models have a good accuracy and a satisfactory behavior.     

Error Description and Modification of Virtual Measuring Instrument

When measuring, virtual instruments are inevitable to cause error damaging the precision of measuring resuits. It presents error constitution, methods of error transfer and synthesis of virtual measuring instrument. Based on the analysis of error transfer and synthesis of virtual measuring tual measuring instrument and gets the method of dealing instrument, it generalizes the error constitution formula of virwith errors. Then, errors can be modifyed.     

Investigation on Improving Manufacturing Precision of ZC1 Worm

Based on coordinate measrement of tooth surface of ZC1 worm, the deviation function for evaluating tooth surface is established. According to minimal zone principle, the profility of tooth surface of worm is evaluated. The machining errors of the worm are divided into setting error and adjusting error of the machine and tool. By error compensation, the setting error and adjusting error are corrected and the manufacturing precision of the worm is improved.     

灌浆压力测量误差的正交试验分析

灌浆规范中的灌浆压力是作用在灌浆岩体上的孔内灌浆压力。由于工艺的约束,现行灌浆监控过程常用孔口压力表示孔内灌浆压力,造成了灌浆压力的测量误差。针对非循环灌浆工艺,通过建立流体管道流动模型开展数值计算,采用多因素多水平正交法探究灌浆压力误差受浆液配比、浆液流速、灌浆孔深的相对影响,并采用统计法来分析不同工况下的显著影响因素。研究结果表明：灌浆压力较小时,灌浆压力误差普遍较大;若此时灌浆孔深且流速较大时,灌浆压力的测量误差则会超过灌浆压力仪表0.5%的精度要求,须进行误差补偿。其次,极差分析结果表明灌浆孔深是造成测量误差的主要因素,灌浆流速是第二个主要因素。而综合所有试验结果,浆液流速和灌浆孔深接近时,浆液配比越小,绝对偏差越大。结合上述正交试验和数值模型获取了不同工况下孔内灌浆压力值。     

Automatic image analysis and spot classification for detection of fruit fly infestation in hyperspectral images of mangoes

Fruit fly infestation of mangos is a major concern for growers and exporters, leading to requirements for quarantine treatments such as vapor heat treatment or irradiation and subsequent reduction in quality and consumer acceptance. An on-line method for detection and removal of infested fruit would thus benefit producers and consumers. An algorithm has been developed to identify spots generated in hyperspectral images of mangoes infested with fruit fly larvae. The algorithm incorporates background removal, application of a Gaussian blur, thresholding, and particle count analysis to identify locations of infestations. Each of the four algorithm steps involves adjustable parameters which were iteratively tested to find the optimal combination for detection in terms of false positive and false negative results. For algorithm parameters selected to minimize false negative results, a false negative error rate of 1.0% was achieved with 11.1% false positive error and 6.0% overall error in heavily infested samples. For the same sample set, the lowest overall error rate achieved was 2.0%, with 1.0% false positive and 3.0% false negative. For samples with lower infestation rates, the error rates were much higher, the lowest overall error being 12.3%. This therefore demonstrates the feasibility of hyperspectral imaging for fruit fly detection while highlighting the need for technology with improved resolution and signal to noise ratio to allow detection of single larvae.     

Method and Analysis of Time Series Model for Transmission Error

This paper presents the time series model of gear drivetrain error and a compari-son amang several typical time series spectrum estimations.and suggests a time series model suitablefor discribing transmission error.     

Analysis on tooth root stress and influencing factors of crossed beveloid gears with small shaft angle

In order to accurately calculate the tooth root stress of spatial crossed beveloid gears with small shaft angle, an exact geometry-based numerical computation method is proposed based on the spatial gearing theory and the finite element theory. Using the proposed method, the mathematical tooth surface model and the mesh model of a crossed beveloid gear pair with small shaft angle is created and the tooth root stress distribution is analyzed. Then the influences of the key design parameter which is the clearance coefficient, torque load, offset error, shaft angle error, pinion axial position error and gear axial position error on the tooth root stress are investigated. The results show that the increasing of the clearance coefficient can decrease the maximum tooth root stress. The root stresses distribute smoothly along the tooth width direction at a light torque load level. For heavy torque load level, the root stresses are parabolic in shape. Also, the existence of offset error and shaft angle error can increase the maximum value of the root stress obviously and the positive and negative value of the errors can change the position of the maximum root stress along opposite direction. For the pinion and gear axial position errors, they have less effect on root stress distribution.     

Components of genetic variation for cut-flower yield in the Davis Population of Gerbera

Summary Genetic variances for cut-flower yield in Gerbera hybrida were partitioned into additive and dominance components. Mean additive variance was 37.3 with a standard error of 12.9. Mean dominance variance was 12.7 with a standard error of 32.6. The dominance ratio was 0.34. Narrow sense heritability, estimated from these components of variance, averaged 0.42 with a standard error of 0.13. Heritabilities estimated from parent-offspring regression averaged 0.25. Gain from selection was less then expected; realized heritabilities were approximately 0.20.     

Wavelet Neural Network Equalizer Using Error Feedback Structure and Algorithm

The inter-symbol interference in the nonlinear time-varying channel is a serious problem in the wireless communication. In order to overcome it, wavelet neural network equalizer using error feedback is employed to cut the auto-correlation of the error signal. Exploiting the decent time-frequency localization of the wavelet analysis, as well as the self-training feature of the neural network, a quicker convergent nalysis and computer simulation confirm the effectiveness of the equalizer and a lower BER are attained. Theoretical aalgorithm. It at The wavelet neural network equalizer based on error feedback advances the communication in the nonlinear time-varying channel.     

Tooth contact analysis of helical beveloid gear with parallel axis

The study object of this paper is helical beveloid gears with parallel axis. Based on the gear Mshing Principles and the tooth-surface equations of pinion and gear,the mathematical model of tooth contact is developed under standard installation and installations with center distance error,axis error and multiple error respectively. The MATLAB solver is used to obtain the contact trace and the transmission error under different installing conditions and the comparative analysis is made. The results indicate that this gear drive is sensitive to axis installation errors,it forms the edge contact and cause the periodic transmission error. It can provide the foundation for designs and analysis of this gear transmission.     

两级星型五分支传动静态均载分析

为分析两级星型五分支传动系统的均载问题,根据该系统构成功率流动闭环的特点,推导扭转角变形协调条件,结合力矩平衡条件,运用当量啮合误差理论,建立静态条件下的均载力学分析模型,求解得到均载系数,分析制造误差、安装误差、构件浮动对均载特性的影响。结果表明：太阳轮、内齿圈、星轮的误差单独影响均载特性时,内齿圈的误差影响最大,各构件制造误差影响的均载系数随时间做周期变化;太阳轮基于花键间隙浮动和内齿圈径向浮动,改善了均载特性,通过试验验证了理论分析的正确性。     

A new determination method of tool step for 5 axis NC machining

The peculiar non linear error in the 5 axis NC machining is studied. An improved tool step determination method for the 5 axis NC machining is proposed, in which the non linear error is compensated. Both the arc chord error and the non linear error are considered when computing the tool step, and the comprehensive error is taken as the function of the tool path parameter. Due to the difficulty of gaining the derivative of this function and the tool step according to the prescribed tolerance, the secant method is improved to guarantee the real solution locating in the converging range which is adopted to compute the tool step. The implementing example shows that the proposed method can compensate the non linear error effectively with meeting the prescribed tolerance. The exact tool step can be gotten efficiently with the improved secant method.     

Digit Weight and Development of a Virtual Noise Analyzer

Traditional noise octave analyzers consist of filter network and weight network based on hardware. In order to realize a noise octave analysis by software, a digit weight method based on FFT is proposed. Using the method, digit weight and digit system error modification for virtual noise octave analyzer can be realized. Because of digit weight and digit system error modification, precision and stability of the instrument can be improved greatly. As an application, which combines the method of digit weight with the technique of digit system error modification, a low cost and high precision virtual real time noise octave analyzer is developed.     

The influence of sensitive gate structure parameters of strain gauge on measurement accuracy

The systematic error of resistance strain sensor is caused by strain transmission error that differs with different parameters of the sensitive gate structure in the measurement process. The paper establishes a measure model that is made up with a cantilever beam(the measured matrix),the binder and some strain wires, then studies the influence of different sensitive gate structure parameters on the measurement result using finite element method(FEM)and the effectiveness of FEM is validated by a comparison with experimental results at the end. The results of the FEM analysis show that in the matrix strain passing the gate length and the gate spacing have intermediate optimal values,and that the smaller the grid diameter is,the smaller the strain transmission error becomes. Besides,the relative errors corresponding to different structural parameters are also given based on the FEM analysis,which provide effective reference for the selection of structural parameters and the appropriate error compensation in the process of measurement.     

畦灌改水成数的控制误差及其对灌水质量的影响

改水成数是地面灌溉设计和管理的基本参数之一。为了更好地进行地面灌溉系统的设计和管理,统计了畦灌改水成数的控制误差,并分析了其对灌水质量的影响。根据实测的16条畦田不同改水成数的控制误差,采用经典统计学方法得到了其统计特征,并采用地面灌溉模拟模型SRFR评价了其对灌水质量的影响。结果表明,改水成数控制误差具有较强的变异性,改水成数对灌水均匀度的影响大于灌水效率。因此,在实际地面灌溉设计与管理中,改水成数的控制误差不可忽略。较大的单宽流量有助于减小改水成数的控制误差对灌水质量的影响。     

The application of grey residual error GM(11)model based on Markvo to aging behavior prediction of plastic

To solve the problem of poor prediction accuracy of GM(11)model when the data are discretebased on the sign of residual error modification value of prediction value being determined by Markvo chaina residual error modification is presented.The grey residual error GM(11)model based on Markvo is constructed through the modification of simulation value and prediction value obtained from GM(11)model.The prediction of tensile strength of LDPE greenhouse film under natural aging condition is taken as an exampleand the applicability of constructed model in the prediction of plastic aging behavior is researched.The results show that the relative error between prediction value and the actual value of tensile strength of LDPE greenhouse film after aging 18 and 21 months obtained from constructed model are 1.49% and 4.96% respectively.Prediction accuracy are higher than that(relative error are 3.40% and 6.75% respectively)obtained from GM(11)model obviously.Grey residual error GM(11)model based on Markvo needs less original data and has high prediction accuracythus it is a simple and reliable method for plastic aging behavior prediction.