Concurrent error detection and correction in dual basis multiplier over GF(2m)

Fault-based side-channel cryptanalysis is a useful technique against symmetrical and asymmetrical encryption/decryption algorithms. Thus, eliminating cryptographic computation errors become critical in preventing such kind of attacks. A simple way to eliminating cryptographic computation errors is to output correct or corrected ciphers. Multiplication is the most important finite field arithmetic operation in the cryptographic computations. By using time redundancy technique, a novel dual basis (DB) multiplier over Galois fields (2^m) will be presented with lower space complexity and feedback-free property. Based on the proposed feedback-free DB multiplier, the DB multiplier with a concurrent error detection (CED) capability is also easily developed. Compared with the existing DB multiplier with CED capability, the proposed one saves about 90% of time-area complexity. No existing DB multiplier in the literature has concurrent error correction (CEC) capability. Based on the proposed DB multiplier, a novel DB multiplier with CEC capability is easily designed. The proposed DB multiplier with CEC capability requires only about 3% of extra space complexity and 15% of time complexity when compared with the proposed DB multiplier without CEC.     

A four quadrant multiplier with independent control of range andsensitivity

An improved analog multiplier using the voltage variable resistance characteristics of a FET is presented. The scheme has independent control of the design condition, sensitivity, and range. A modified version, with a marginal increase in hardware but embodying the same operating principles, can work in all four quadrants in both DC and AC operations. The proposed multiplier is superior in performance to earlier schemes based on the same technique. Its design condition is independent of the inputs, unlike the earlier ones. Experimental results and appropriate error analysis are presented     

Error estimation of quadrature rules for evaluating singular integrals in boundary element problems

The efficient numerical evaluation of integrals arising in the boundary element method is of considerable practical importance. The superiority of the use of sigmoidal and semi‐sigmoidal transformations together with Gauss–Legendre quadrature in this context has already been well‐demonstrated numerically by one of the authors. In this paper, the authors obtain asymptotic estimates of the truncation errors for these algorithms. These estimates allow an informed choice of both the transformation and the quadrature error in the evaluation of boundary element integrals with algebraic or algebraic/logarithmic singularities at an end‐point of the interval of integration. Copyright © 2000 John Wiley & Sons, Ltd.     

A priori error estimation of finite element models from first principles

The quality of finite element computational results can be assessed only by providing rational criteria for evaluating errors. Most exercises in this direction are based ona posteriori error estimates, based primarily on experience and intuition. If finite element analysis has to be considered a rational science, it is imperative that procedures to computea priori error estimates from first principles are made available. This paper captures some efforts in this direction.     

The problem of analyzing errors in measuring systems

Summary In the operation of a linear measuring system with its elements subjected to various random external disturbances which produce in the elements additional static errors, transmitted to the output of the system together with the basic errors of the elements, a total static error is produced at the output. The latter error is the one which determines the accuracy of the measuring system under given conditions.If in experimental work the required variable is measured several times by means of a measuring system, whose elements are subjected to various random external disturbances, a statistical analysis of the measurement results may produce a certain compensation of the static measurement errors of this variable.     

Precision and information indicators of the measurement channels of an engine expert system

The errors in the internal combustion engines measuring channels of a measurement expert system, in particular, the error accumulation in the passage of a signal from the sensor to the processor device, are considered. The information indicators of the individual components of the measuring channel (adder, differential multiplier, analog-to-digital converter) as well as the channel as a whole are determined.     

An additional stiffness parameter measure of error of the second kind in the finite element method

Conventional error analyses norms in the finite element method are based on the percentage error or its equivalent in some computed value as compared to the theoretically predicted value. In problems where two or more field variables are coupled, it is possible that if the field interpolation functions do not ‘consistently’ reproduce limiting situations of physical behaviour, there may be very large errors which are exaggerated enormously when some structural parameters become indefinitely large in a penalty limiting sense. The percentage error norms therefore saturate quickly to a value approaching 100 per cent and do not sensibly reflect the relationship between error and the structural parameter, even on a logarithmic plot. Errors due to these spurious constraints have recently been recognized as belonging to a special class described as ‘errors of the second kind’. A new error norm, called the additional stiffening parameter, helps to recognize the manner in which errors of the second kind can be blown out, of propprtion by a large variation in some structural parameter. Recent investigations in some multi-field problems are summarized here to demonstrate the usefulness of this concept.     

三角波调制式时分割交流功率测量误差的仿真估计

三角波调制式时分割交流乘法器广泛应用在电功率和电能量的测量中。本通过建立该种乘法器的数学模型和仿真模型，详细分析了被测信号的外部参数三角波调制式时分割乘法器的内部参数变化对交流功率测量误差的影响。中所得的分析结论及误差曲线对使用、分析和设计该原理的功率电能仪器具有指导意义。     

On the use of shadows in stance recovery

The image of an object and of the shadow it casts on a planar surface provides important cues for three‐dimensional (3D) stance recovery. We assume that the position of the plane on which the shadow lies with respect to a pinhole camera is known and that the position of the light source is unknown. If the light source is sufficiently far away that parallel projection may be assumed, then knowledge of two point correspondences between images of feature points and images of their shadows is enough to determine the position of the object and the direction of the light source. If the light source is close enough that the shadow points are obtained via perspective projection, then there is a one‐parameter infinite family of solutions for the position of the object and the light source. Determining the stance of an object is highly sensitive to noise, so we provide algorithms for stance recovery that take into account known information about the object. In our experiments, the errors for the location of the 3D feature points obtained by these algorithms are generally less than 0.2% times the error in pixels in the image points and the errors for the 3D directions of the links is roughly 0.04° times the error in pixels, normalized by the distance to the object from the camera and the length of the link. © 2001 John Wiley & Sons, Inc. Int J Imaging Syst Technol, 11, 315–330, 2000     

Model-based image reconstruction by means of a constrained least-squares solution

The problem of the optimal use of object model information in image reconstruction is addressed. A closed-form solution for the estimated object spectrum is derived with the Lagrange multiplier technique, which assumes a measured image, knowledge of the optical transfer function, statistical information about the measurement noise, and a model of the object. This reconstruction algorithm is iterative in nature because the optimal Lagrange multiplier is not generally known at the start of the problem. We derive the estimator, describe one technique for determining the optimal Lagrange multiplier, demonstrate a stopping criterion based on the mean-square error between a noise-free image and the photon-limited version of the image, and show representative results for both filled- and sparse-aperture imaging applications.     

基于对偶四元数的单目视觉目标位姿测量

目的在机器人视觉应用领域中,为控制机器人能够完成焊接、搬运、跟踪等任务,需要确定摄像机与目标之间的相对位姿关系,提出一种目标位姿测量方法。方法利用单摄像机获取目标特征,坐标变换参数表示为对偶四元数的形式,同时计算旋转矩阵和平移向量,构建位置向量和方向向量的测量值与模型值之间的误差方程,利用Hopfield神经网络实现拉格朗日乘子法,求解目标位姿最优解。结果利用Matlab软件平台,选择SVD,DQ以及文中算法进行比较,仿真实验结果表明,基于Hopfield神经网络和对偶四元数的位姿测量算法计算出的位姿参数误差最小。随着测量点数量的增大,文中提出的算法精度更高。结论对偶四元数同时求解位姿变换矩阵的旋转分量和平移分量,可消除计算误差,基于Hopfield神经网络和拉格朗日乘子法,可快速准确地计算,并收敛至目标位姿最优解。     

Algorithm immune to tilt phase-shifting error for phase-shifting interferometers

As a phase shifter usually suffers from both translational and tilt-shift errors during shifting, so every pixel in the same interferogram will have a different phase-shift value. Thus nonlinear phase-measurement errors cannot be avoided, but even translational-shift error has been corrected effectively. However, based on the fact that the shifted phases of all the pixels in the same interferogram remain on the phase-shift plane, by defining this plane one can eliminate a significant number of phase errors. A new algorithm that is immune to both translational- and tilt-shift errors in a phase shifter for phase-stepping interferometers is presented. A first-order Taylor series expansion replaces the nonlinear equations for defining the phase-shift plane, and iteration of the algorithm guarantees its accuracy. Results of a computer simulation show that phase-measurement errors caused by both translation- and tilt-shift error can be compensated for completely, even when the tilt-shift error is not more than ?1%.     

一种基于神经网络的硅基光伏组件运行温度在线软测量方法

硅基光伏组件的运行温度对组件电气性能和发电效率具有显著影响,是光伏系统建模和性能评估的重要参数,它的精确计算对于光伏系统分析和最大功率跟踪等算法的应用等具有重要意义。通过对组件运行温度经典计算方法进行实例验证,发现该算法在不同季节、天气条件下的精度不一致,使得光伏电站发电量的计算与实际状况存在较大误差。针对这一问题,提出了一种基于多层反向传播（back propagation,BP）神经网络的硅基光伏组件运行温度在线建模方法,它分别以实测太阳辐照度、环境温度和输出功率作为模型输入,以组件运行温度作为模型输出,实现了组件运行温度的在线软测量。通过实际运行数据的对比表明上述方法是有效的,在条件允许时,也应该将风速作为模型输入之一。     

Kalman滤波中测量粗差的探测与修复

在动态定位的数据处理中动态观测量可能存在粗差,若数据处理不考虑对这些异常的特别处理,则所提供的动态信息将极不可靠。文中计算了粗差对滤波结果的影响,并由此建立了动态定位中粗差的探测和修复算法。最后用数字仿真实验论证了方法的可行性。     

Interpolation errors in UV-visible spectroscopy for stratospheric sensing: implications for sensitivity, spectral resolution, and spectral range

UV-visible measurements of stratospheric constituents require the ratio of a pair of spectra to be determined. If their wavelength calibrations differ and if an array detector is used, at least one spectrum must be interpolated. This introduces error if the spectrum is undersampled; the error is smaller if wavelength stability is good. Increasing the sampling ratio by making the spectral resolution poorer reduces the optical depths of absorption by constituents. Exact values of interpolation errors from real spectra are a difficult topic, but with a theoretical study with a simulated spectrum we show that the sampling ratio should exceed ~4.5 pixels/FWHM but need not exceed 6.5 pixels/FWHM. To avoid significant reduction in the optical depth of NO(2), the resolution should be smaller than ~1.0 nm FWHM. Hence a spectrometer system that measures both OClO and NO(3) by observing one order from one stationary grating should have more than ~1500 pixels, more than many currently available array detectors.     

微纳米三坐标测量机三轴垂直度误差测量及建模补偿

垂直度误差是微纳米三坐标测量机的重要误差源之一,必须对其进行高精度测量并建立垂直度误差的补偿模型.采用基于光电位置敏感器件(PSD)的测量装置,先将三轴垂直度误差转化成相应方向的直线度误差再对其进行测量,并对微纳米三坐标测量机的垂直度误差进行建模和补偿.通过对0级标准量块厚度进行测量和垂直度误差补偿,量块X、Y方向厚度...     

Design of custom potentiometers

Using analytical solutions of the potential equation, a technique has been worked out to generate a resistor geometry with a prescribed potential drop along one free boundary (the wiper path). If a wiper is placed on this line, a custom potentiometer with an a priori given characteristic can be designed. The advantage is that only a single resistive layer is involved. The characteristic is obtained by adjusting the two-dimensional geometry. Even extreme cases such as logarithmic potentiometers can be handled     

Errors in determining hardness by means of impact-type instruments

Conclusions The comparative evaluation of errors for impact-type instruments leads to the conclusion that the Nikolaev instrument (± 11.5%) has the smallest error in determining the HB hardness of various ferrous metals. After certain improvements this error was reduced to 10%. The Poldi instrument has an error of ±7%, providing the reference sample is made of the same material as the one whose hardness it is required to determine.     

Temperature Dependence of Fixed Pattern Noise in Logarithmic CMOS Image Sensors

This paper presents a model that is then simplified to explain the temperature dependence of fixed pattern noise (FPN) in logarithmic complementary metal–oxide semiconductor (CMOS) image sensors. The simplified model uses the average dark response of pixels, which depends only on temperature, to help predict the FPN in the light response, which depends on temperature and illuminance. To calibrate a logarithmic camera, one requires images that are taken at different temperatures and illuminances, which need not be measured, of a uniform stimulus. To correct the FPN in an arbitrary image, one uses the simplified model parameters, which are estimated once by the calibration, and the average dark response, which is infrequently determined by closing the aperture. Through simulation (using mismatch data from a real CMOS process) and experiment (using a commercial logarithmic camera), an improvement is shown in the residual error per image, after calibration, when the proposed method is compared with a related method in the literature that does not account for temperature dependence.      

A calibration method that simplifies and improves accurate determination of peptide molecular masses by MALDI-TOF MS

The use of delayed ion extraction in MALDI time-of-flight mass spectrometry distorts the linear relationship between m/z and the square of the ion flight time (t2) with the consequence that, if a mass accuracy of 10 ppm or better is to be obtained, the calibrant signals have to fall close to the analyte signals. If this is not possible, systematic errors arise. To eliminate these, a higher-order calibration function and thus several calibrant signals are required. For internal calibration, however, this approach is limited by signal suppression effects and the increasing chance of the calibrant signals overlapping with analyte signals. If instead the calibrants are prepared separately, this problem is replaced by an other; i.e., the ion flight times are dependent on the sample plate position. For this reason, even if the calibrants are placed close to the sample, the mass accuracy is not improved when a higher-order calibration function is applied. We have studied this phenomenon and found that the relative errors, which result when moving from one sample to the next, are directly proportional to m/z. Based on this observation, we developed a two-step calibration method, that overcomes said limitations. The first step is an external calibration with a high-order polynomial function used for the determination of the relation between m/z and t2, and the second step is a first-order internal correction for sample position-dependent errors. Applying this method, for instance, to a mass spectrum of a mixture of 18 peptides from a tryptic digest of a recombinant protein resulted in an average mass error of 1.0 ppm with a standard deviation of 3.5 ppm. When instead using a conventional two-point internal calibration, the average relative error was 2.2 ppm with a standard deviation of 15 ppm. The new method is described and its performance is demonstrated with examples relevant to proteome research.