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GPS short-delay multipath estimation and mitigation based on least square method

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Journal of Systems Engineering and Electronics 2009年第5期20卷 954-961页

作者： Zhang Shengkang~(1,2),Wang Hongbo~(1,2),Yang Jun~(1,2) & He Leiming~(1,2) 1.Beijing Inst.of Radio Metrology and Measurement,Beijing 100854,P.R.China 2.National Key Laboratory of Metrology and Calibration Technology,Beijing 100854,P.R.China Beijing Inst. of Radio Metrology and Measurement Beijing 100854 P. R. China National Key Laboratory of Metrology and Calibration Technology Beijing 100854 P. R. China

The GPS multipath signal model is presented, which indicates that the coherent DLL outputs in multipath environment are the convolution between the ideal DLL outputs and the channel responses. So the channel responses can be estimated by a least square method using the observed curve of the DLL discriminator. In terms of the estimated multipath channels, two multipath mitigation methods are discussed, which are equalization filtering and multipath subtracting, respectively. It is shown, by computer simulation, that the least square method has a good performance in channels estimation and the multipath errors can be mitigated almost completely by either of the methods. However, the multipath subtracting method has relative small remnant errors than equalization filtering.

关键词： global positioning system short-delay least square method multipath mitigation.

Constant Stress Accelerated Life Tests for Vacuum Fluorescent Display Based on least square method

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Journal of Southwest Jiaotong University(English Edition) 2010年第1期18卷 45-50页

作者：张建平王睿韬 School of Thermal Power and Environmental Engineering Shanghai University of Electric Power

To estimate the life of vacuum fluorescent display （VFD） more accurately and reduce test time and cost, four constant stress accelerated life tests （CSALTs） were conducted on an accelerated life test model. In the model, statistical analysis of test data is achieved by applying lognormal function to describe the life distribution, and least square method （LSM） to calculate the mean value and the standard deviation of logarithm. As a result, the accelerated life equation was obtained, and then a self-developed software was developed to predict the VFD life. The data analysis results demonstrate that the VFD life submits to lognormal distribution, that the accelerated model meets the linear Arrhenius equation, and that the precise accelerated parameter makes it possible to acquire the life information of VFD within one month.

关键词： Vacuum fluorescent display Constant stress Accelerated life tests least square method Lognormal distribution

Probabilistic back analysis for geotechnical engineering based on Bayesian and support vector machine

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Journal of Central South University 2015年第12期22卷 4778-4786页

作者：陈炳瑞赵洪波茹忠亮李贤 State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of Sciences School of Civil Engineering Henan Polytechnic University School of Resource and Environmental Engineering Wuhan University of Science and Technology

Geomechanical parameters are complex and *** order to take this complexity and uncertainty into account,a probabilistic back-analysis method combining the Bayesian probability with the least squares support vector machine(LS-SVM) technique was *** Bayesian probability was used to deal with the uncertainties in the geomechanical parameters,and an LS-SVM was utilized to establish the relationship between the displacement and the geomechanical *** proposed approach was applied to the geomechanical parameter identification in a slope stability case study which was related to the permanent ship lock within the Three Gorges project in *** results indicate that the proposed method presents the uncertainties in the geomechanical parameters reasonably well,and also improves the understanding that the monitored information is important in real projects.

关键词： geotechnical engineering back analysis uncertainty Bayesian theory least square method support vector machine(SVM)

Algorithm for Detecting Volumetric Geometric Accuracy of NC Machine Tool by Laser Tracker

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Chinese Journal of Mechanical Engineering 2013年第1期26卷 166-175页

作者： WANG Jindong GUO Junjie State Key Laboratory for Manufacturing Systems Engineering Xi'an Jiaotong University

Quick and accurate detecting the error of NC machine tool and performing the error compensation are important to improve the machining accuracy of NC machine tool. Currently, there are many methods for detecting the geometric accuracy of NC machine tool. However, these methods have deficiencies in detection efficiency and accuracy as well as in versatility. In the paper, a method with laser tracker based on the multi-station and time-sharing measurement principle is proposed, and this method can rapidly and accurately detect the geometric accuracy of NC machine tool. The machine tool is controlled to move in the preset path in a 3D space or 2D plane, and a laser tracker is used to measure the same motion trajectory of the machine tool successively at different base stations. The original algorithm for multi-station and time-sharing measurement is improved. The space coordinates of the measuring point obtained by the laser tracker are taken as parameter values, and the initial position of each base point can be determined. The redundant equation concerning the base point calibration can be established by the distance information of the laser tracker, and the position of each base point is further determined by solving the equation with least squares method, then the space coordinates of each measuring point can be calibrated. The singular matrix does not occur in calculation with the improved algorithm, which overcomes the limitations of the original algorithm, that the motion trajectory of machine tool is in a 3D space and there exits height difference between the base stations. Adopting the improved algorithm can expand the application of multi-station and time-sharing measurement, and can meet the quick and accurate detecting requirements for different types of NC machine tool.

关键词： laser tracker NC machine tool geometric accuracy redundant equation singular matrix least square method

Efficient collision attacks on smart card implementations of masked AES

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Science China(Information Sciences) 2015年第5期58卷 97-111页

作者： WANG An WANG ZongYue ZHENG XueXin WANG XiaoMei CHEN Man ZHANG GuoShuang WU LiJi Institute of Microelectronics Tsinghua University Key Laboratory of Cryptologic Technology and Information Security Ministry of EducationShandong University China Academy of Electronics and Information Technology School of Computer and Communication Engineering University of Science and TechnologyBeijing Science and Technology on Communication Security Laboratory

Collision attack is often employed against some cryptographic algorithms such as AES and *** a usual countermeasure, masking can resist such attacks to some extent. In CHES 2011, Clavier et *** a collision-correlation attack based on Pearson correlation coefficient against masking. In this paper, a collision distinguisher based on least absolute deviation against masking is proposed. Subsequently, we suggest three other distinguishers based on least square method, least exponent method, and central moment product,respectively. Our experiments and simulations show that in practice, our distinguishers based on least absolute deviation and least square method perform much better than collision-correlation attack and other proposed distinguishers in this paper. We also give four application examples, which show that even if the masks are not reused, new distinguishers are competent to collision attacks.

关键词： power analysis attack collision attack least absolute deviation least square method masking

A High Precision Software Compensation Algorithm for Silicon Piezoresistive Pressure Sensor

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Chinese Journal of Electronics 2019年第4期28卷 748-753页

作者： WU Tianshu CHEN Shuyu WU Peng NIE Shaozhong College of Computer Science Chongqing University Chongqing Chuanyi Automation Co. Ltd.

There are generally zero drift, sensitivity drift and nonlinear error in silicon piezoresistive pressure sensors due to the inherent characteristics of semiconductor materials. It is necessary to compensate and correct the errors produced so as to meet the requirements of measurement accuracy. In order to further improve the compensation precision, based on the research of various basic software compensation methods, a surface fitting compensation algorithm based on least square method is designed, and the software is implemented on the Visual Basic platform. The experimental results show that the zero drift, sensitivity drift and nonlinear error is effectively eliminated, and the output precision of the sensor is greatly improved.

关键词： High precision compensation algorithm least square method Surface fitting

Electrical model parameters identification of radiofrequency discharge in argon through 1D3V/PIC-MC model

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Plasma Science and Technology 2018年第9期20卷 106-113页

作者： Mohamed MOSTAFAOUI Djilali BENYOUCEF Laboratoire Génie Electrique et Energies Renouvelables Université Hassiba Benbouali de Chlef

This work represents a contribution to the modeling of a radiofrequency（RF） discharge in argon at low pressure（from 25 to 200 mTorr）.It is started by the validation of the collision cross sections used in the particle model through a comparison between the transport coefficients calculated by these data and the measurements of the transport coefficients already exist in the literature,the particle model is also validated by a comparison between the calculated plasma density and that measured in the *** electrical model proposed in this work consists of replacing the RF discharge by a passive circuit（resistance in series with a capacitor）,where the resistance represents the plasma medium and the obstruction of the passage of the electronic current,and the capacitor represents the sheaths and the appearance of the displacement current in these *** parameters of the electrical model are obtained through particle *** electrical model presented accurately reproduces the current of the discharge,but without considering the phenomenon of *** total harmonic distortion rate follows the variation of the plasma density;its maximum value is 5.75% at 100 mTorr.

关键词： electrical model least square method particle model radiofrequency discharge static parameters identification

A Hybrid Learning method for the Data-Driven Design of Linguistic Dynamic Systems

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IEEE/CAA Journal of Automatica Sinica 2019年第6期6卷 1487-1498页

作者： Chengdong Li Jianqiang Yi Yisheng Lv Peiyong Duan School of Information and Electrical Engineering Shandong Jianzhu UniversityJinan 250101China Institute of Automation Chinese Academy of SciencesBeijing 100190China Institute of Automation Chinese Academy of SciencesBeijing 100190and also with Qingdao Academy of Intelligent IndustriesQingdao 266109China School of Information Science and Engineering Shandong Normal UniversityJinan 250014China

In lots of data based prediction or modeling applications,uncertainties and/or noises in the observed data cannot be *** such cases,it is more preferable and reasonable to provide linguistic(fuzzy)predicted results described by fuzzy memberships or fuzzy sets instead of the crisp estimates depicted by *** dynamic system(LDS)provides a powerful tool for yielding linguistic(fuzzy)***,it is still difficult to construct LDS models from observed *** solve this issue,this paper first presents a simplified LDS whose inputoutput mapping can be determined by closed-form ***,a hybrid learning method is proposed to construct the data-driven LDS *** proposed hybrid learning method firstly generates fuzzy rules by the subtractive clustering method,then carries out further optimization of centers of the consequent triangular fuzzy sets in the fuzzy rules,and finally adopts multiobjective optimization algorithm to determine the left and right end-points of the consequent triangular fuzzy *** proposed approach is successfully applied to three real-world prediction applications which are:prediction of energy consumption of a building,forecasting of the traffic flow,and prediction of the wind *** results show that the uncertainties in the data can be effectively captured by the linguistic(fuzzy)*** can also be extended to some other prediction or modeling problems,in which observed data have high levels of uncertainties.

关键词： Fuzzy set least square method linguistic dynamic system(LDS) multi-objective optimization

Estimation for constant-stress accelerated life test from generalized half-normal distribution

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Journal of Systems Engineering and Electronics 2017年第4期28卷 810-816页

作者： Liang Wang Yimin Shi School of Mathematics and Statistics Xidian University Department of Applied Mathematics Northwestern Polytechnical University

In the constant-stress accelerated life test, estimation issues are discussed for a generalized half-normal distribution under a log-linear life-stress model. The maximum likelihood estimates with the corresponding fixed point type iterative algorithm for unknown parameters are presented, and the least square estimates of the parameters are also proposed. Meanwhile, confidence intervals of model parameters are constructed by using the asymptotic theory and bootstrap technique. Numerical illustration is given to investigate the performance of our methods.

关键词： accelerated life test maximum likelihood estimation least square method bootstrap technique asymptotic distribution