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ON THE CONVERGENCE OF PARALLEL bfgs METHOD

Acta Mathematica Scientia 1995年第3期15卷 283-294页

作者：陈忠费浦生 WUHAN UNIV DEPT MATHWUHAN 430072PEOPLES R CHINA JIANGHAN PETR INST JINSHA 434102PEOPLES R CHINA

According to the sequential bfgs method, in this paper we present an asynchronous parallel bfgs method in the case when the gradient information about the function is inexact. We assume that we have p + q processors, which are divided-into two groups, the first group has p processors, the second group has q processors, the two groups are asynchronous. parallel, If we assume the objective function is twice continuously differentiable and uniformly convex, we prove the iteration converge globally to the solution, and under some additional conditions we show the method is superlinearly convergent. Finally, we show the numerical results of this algorithm.

关键词： bfgs algorithm superlinear convergence parallel method

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Design of a multi-voltage probe system for ICRF antenna coupling resistance measurement on EAST

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Plasma Science and Technology 2020年第10期22卷 145-151页

作者： Zhen PENG Gen CHEN Jianhua WANG Yanping ZHAO Yuzhou MAO Institute o f Plasma Physics Chinese Academy of SciencesHefei 230031People's Republic of China University of Science and Technology of China Hefei 230026People's Republic of China Hangzhou Dianzi University Hangzhou 310018.People's Republic of China

A multi-voltage probe array system is designed to measure the coupling resistance of an ion cyclotron resonance frequency antenna. In the process of the antenna coupling resistance data extraction, the minimization algorithm, the original Levenberg–Marquardt algorithm, is replaced by the Broyden–Fletcher–Goldfarb–Shanno algorithm to achieve more stable and accurate results. Moreover, a simple model of the multi-voltage probe array was applied to simulate the performance of the Kalman filter, and to optimize the distance and position of the probes and probe number to mitigate the influence of the system noise on the rebuilt results. During the EAST experiment in 2019, a four-voltage probe array was applied to measure the coupling resistance of line 6 during high confined mode discharge. The measurement results by the multivoltage probe array system and the voltage/current probe pair show a good agreement.

关键词： EAST ICRF bfgs algorithm multi-voltage probe coupling resistance

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Prediction of Flow Duration Curves for Ungauged Basins with Quasi-Newton Method

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Journal of Water Resource and Protection 2013年第1期5卷 97-110页

作者： Mutlu Yasar Neset Orhan Baykan Department of Civil Engineering Pamukkale UniversityDenizliTurkey

Prediction of flow-duration-curves (FDC) is an important task for water resources planning, management and hydraulic energy production. Classification of the basins as carstic and non-carstic may be used to estimate parameters of the FDC with predictive tools for catchments with/without observed stream flow. There is a need for obtaining FDC for ungauged stations for efficient water resource planning. Thus, study proposes a quite new approach, called the EREFDC model, for estimating the parameters of the FDC for which the parameters of the FDC are obtained with quasi-Newton method. Estimation are made for using the bv gauged stations at first than the FDC parameters are estimated for ungauged stations based on drainage area, annual mean precipitation, mean permeability, mean slope, latitude, longitude, and elevation from the mean sea level are used. The EREFDC model consists of various type of linear- and nonlinear mathematical equations, is able to predict a wide range of the FDC parameters for gauged and ungauged basins. The method is applied to 72 unimpaired catchments studied are about for 50 years average daily measured stream flow. Results showed that the EREFDC model may be used for estimating. FDC parameters for ungauged hydrological basins in order to find FDC for ungauged stations. Results also showed that the EREFDC model performs better in carstic regions than non-carstic regions. In addition, parameters of FDC for tributaries at the basins with insufficient flow data or without flow data may be determined by using basin characteristics.

关键词： Flow Duration Curve Optimization bfgs algorithm Basin Characteristics

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