基于DSP2812的光伏MPPT控制系统

光伏电池的输出特性存在一个随外界环境变化而变化的最大功率点。为了能够最大限度地利用光伏转化出来的电能,必须进行最大功率点跟踪。采用DSP2812芯片用于最大功率点跟踪的主控制器并选择Boost拓扑作为主电路结构,介绍了采样电路和驱动电路等硬件电路的设计、软件与控制策略的设计。最终用实验验证了该控制系统能够快速稳定地跟踪光伏电池的最大功率点。     

实对称矩阵的广义Cholesky分解及扰动

设N为实对称矩阵，证得当p（N）〈1时。存在唯一分解J＋N=（I＋L）J（I＋L）^T；在此基础上，得到一些新的扰动结论，对以往的结果略有改进。     

微分系统持续摄动下部分变元的强稳定性

运用Liapunov直接法研究了微分系统在持续摄动下部分变元的强稳定性、强渐近稳定性.     

类锂离子(Z=3-30)基态非相对论能量的递推计算

给出一种简单的计算类锂离子(Z=3-30)基态非相对论能量的方法。首先以类氢离子的能量为零级近似能 量,用微扰法计算了类氪离子1s2s态的能量;然后以类氮离子的能量为零级近似能量,用微扰法计算了类锂离子的 基态1s22s能量。结果与其它理论值符合得很好,表明该方法是可行的。     

Microdata disclosure by resampling – Empirical findings for business survey data

Summary: One specific problem statistical offices and research institutes are faced with when releasing microdata is the preservation of confidentiality. Traditional methods to avoid disclosure often destroy the structure of the data, and information loss is potentially high. In this paper an alternative technique of creating scientific–use files is discussed, which reproduces the characteristics of the original data quite well. It is based on Fienberg (1997, 1994) who estimates and resamples from the empirical multivariate cumulative distribution function of the data in order to get synthetic data. The procedure creates data sets – the resample – which have the same characteristics as the original survey data. The paper includes some applications of this method with (a) simulated data and (b) innovation survey data, the Mannheim Innovation Panel (MIP), and a comparison between resampling and a common method of disclosure control (disturbance with multiplicative error) with regard to confidentiality on the one hand and the appropriateness of the disturbed data for different kinds of analyses on the other. The results show that univariate distributions can be better reproduced by unweighted resampling. Parameter estimates can be reproduced quite well if the resampling procedure implements the correlation structure of the original data as a scale or if the data is multiplicatively perturbed and a correction term is used. On average, anonymization of data with multiplicatively perturbed values protects better against re–identification than the various resampling methods used.     

Effect on probabilities and quantiles of adding a quantity with small variance

This paper gives simple approximations for the distribution function and quantiles of the sum X + Y when X is a continuous variable and Y is an independent variable with variance small compared to that of X . The approximations are based around the distribution function or quantiles of X and require only the first two or three moments of Y to be known. Example evaluations with X having a normal, Student's t or chi-squared distribution suggest that the approximations are good in unbounded tail regions when the ratio of variances is less than 0.2.     

INFLUENCE DIAGNOSTICS IN PROPER DISPERSION MODELS

This paper discusses the application of influence diagnostic methods in univariate proper dispersion models. This class includes, in particular, continuous generalized linear models as well as other subclasses of continuous regression models. We emphasize the study of the local influence on the likelihood displacement and predictions from the models. Some of the diagnostics are illustrated by an example on directional data.     

可对称化矩阵特征值的Weyl型和Wielandt型扰动界

该文利用矩阵的奇异值分解得到了可对称化矩阵特征值的Weyl型和Wielandt型绝对扰动上界,并推广了Weyl-ЛиДский定理和Wielandt-Hoffman定理.     

（3＋1）维Kadomtsev-Petviashvili方程的N孤子解

利用Hirota双线性导数和形式摄动方法得到了（3＋1）维Kadomtsev-Petviashvili方程的单孤子解、双孤子解及N孤子解的解析表达式.     

曲面工件超声检测机器人误差补偿分析

针对曲面工件超声波检测过程中,超声检测机器人末端探头位姿误差对检测精度影响的问题。根据超声检测机器人自身特点,提出基于多关节摄动误差补偿原理逆向求解标定误差模型参数的方法,利用误差模型参数实现对检测中所有扫描点位姿误差的实时补偿,提高检测的精度。首先,应用Denavit-Hartenberg方法建立超声检测机器人的运动学模型;其次,分析超声检测机器人的误差原因和来源,并利用矩阵微分原理建立误差模型;最后,结合超声检测机器人测距功能和多关节摄动误差补偿原理得到位姿误差实时补偿方法。通过螺旋桨曲面工件扫描检测实验验证该位姿误差补偿方法的有效性。