蜂群算法在光伏电池双二极管五参数模型中的应用

为解决光伏电池双二极管五参数模型中参数辨识准确度低的问题,提出了一种人工蜂群算法.该方法采用曲线拟合来求取参数,用求出的电流计算值来比较标准化的均方根误差百分比.采用变量替换法,使双二极管模型方程中指数因子只含一个变量,通过编程求解电流的计算值.运用蜂群算法和牛顿-拉夫逊法求得标准化的均方根误差百分比为0.011 7%和6.35%.实验及分析表明蜂群算法的优化准确度明显优于牛顿-拉夫逊解析法、遗传算法、模式搜索算法和模拟退火算法,为光伏电池参数辨识提供了一种新的思路.     

Patrolling a perimeter

In this paper we study the problem of patrolling a perimeter. The general situation considered here can correspond to different tactical problems and it is studied from the point of view of game theory. To put the ideas in a context we describe it as follows. An intruder seeks to carry out a sabotage on the perimeter of a protected zone. He has to perform the action along n consecutive days and has to position himself each day at one of m strategic points placed on this border. The first day he can take his place at any of the m points, but on successive days he can move only to adjacent points. Furthermore, the perimeter is protected by a patroller, who will select each day one of the m points to inspect. The strategic situation is modeled as a two-person zero-sum game, which is developed on a cyclic set of m points over n time units. We prove some interesting properties of the strategies, solve the game in closed form under certain constraints and obtain bounds for the value of the game in several non-solved cases.     

From deterministic to stochastic surrender risk models: Impact of correlation crises on economic capital

In this paper we raise the matter of considering a stochastic model of the surrender rate instead of the classical S-shaped deterministic curve (in function of the spread), still used in almost all insurance companies. For extreme scenarios, due to the lack of data, it could be tempting to assume that surrenders are conditionally independent with respect to a S-curve disturbance. However, we explain why this conditional independence between policyholders decisions, which has the advantage to be the simplest assumption, looks particularly maladaptive when the spread increases. Indeed the correlation between policyholders decisions is most likely to increase in this situation. We suggest and develop a simple model which integrates those phenomena. With stochastic orders it is possible to compare it to the conditional independence approach qualitatively. In a partially internal Solvency II model, we quantify the impact of the correlation phenomenon on a real life portfolio for a global risk management strategy.     

Uncertainty due to the quantification step in analytical methods

The quantification step is an important source of uncertainty in analytical methods, but it is frequently misunderstood and disregarded. In this paper, it is shown how this uncertainty is closely related to the linear response range of a method, and to the Pearson correlation coefficient of the calibration line. So, if there is a need for a pre-fixed quantification uncertainty, the linear response range will be affected. Some practical cases are given showing the quantification uncertainty significance. The theoretical equation giving the value of the quantification uncertainty is deduced from which new conclusions can be taken out. Because of that, the quantification uncertainty can easily be calculated and the parameters that really affect its value are shown along the paper. Some final considerations about detection limits and two-point calibration lines are also given. The paper can also be considered a reflection on uncertainty owed to calibration and on their consequences on the analytical methodology.     

A search algorithm for linear codes: progressive dimension growth

This paper presents an algorithm, called progressive dimension growth (PDG), for the construction of linear codes with a pre-specified length and a minimum distance. A number of new linear codes over GF(5) that have been discovered via this algorithm are also presented.      

Correlation Inequalities

The main point of this note is to give a simple semigroup proof of a correlation inequality due to Hu , [H]. We also recover recent correlation inequalities due to Houdré , Pérez–Abreu and Surgailis , [HPS] and obtain some new correlation inequalities on Lie groups.     

EAST边界和芯部杂质谱线的时间延迟研究

边界杂质注入是未来聚变装置ITER用于增强边界辐射,减少第一壁热负荷的一种重要方法。但部分注入的杂质会被输运到芯部,造成主等离子体辐射损失以及约束下降。光谱观测可以获取杂质种类、含量和分布等信息,在理解等离子体中杂质输运方面起着重要作用。在EAST(experimental advanced superconducting tokamak)偏滤器氩气(Ar)注入实验中,利用偏滤器可见光谱和芯部极紫外光谱监测边界的Ar¹⁺离子谱线ArⅡ(401.36 nm)和芯部的Ar¹⁵⁺离子谱线ArⅩⅥ(35.39 nm),并获得两者强度随时间的变化。其中,ArⅡ和ArⅩⅥ的电离能分别为27和918 eV,因此,ArⅡ和ArⅩⅥ分别对应分布于等离子体边界和芯部Ar离子。为了分析二者谱线强度随时间变化的特征,发展了一种基于正则Pearson积矩相关系数的相关分析方法,计算得到两者谱线强度变化的相对延迟时间,以此表征杂质从边界向芯部输运的时间。结果显示,偏滤器注入Ar杂质后,芯部ArⅩⅥ辐射增长滞后于边界ArⅡ辐射的增长,并且在具有较高的低杂波加热功率的放电中...     

基于ICP-MS及多元统计分析相结合的地黄酵素发酵前后无机元素特征

探讨地黄酵素制备前后无机元素的变化,分析发酵对地黄中无机元素的影响,为地黄酵素的制备开发提供数据支撑和理论依据。以四批不同来源的地黄为原料,利用乳酸菌和酵母菌发酵制备地黄酵素,采用微波消解-电感耦合等离子质谱(ICP-MS)法结合主成分分析、差异性分析和Pearson相关性分析等多元统计学方法对地黄酵素发酵前后样品中24种无机元素含量变化特征进行研究。结果表明,发酵对地黄原料中无机元素的种类没有影响,但对无机元素的含量影响较大,发酵前后24种无机元素的分类特征明显不同,其中发酵前后Na、P、Mn、Se、Sr和Cd 6种元素的含量差异在统计学上达到显著水平,而且地黄酵素发酵过程中各无机元素之间的代谢相互影响,其中Ca和Ti之间存在极显著的正相关关系,Pearson相关系数高达0.97;P和Mn, Ba和Pb存在显著的负相关关系,Pearson相关系数在-0.80以下。采用所建立的电感耦合等离子体质谱法测定中草药保健食品地黄酵素中的无机元素,并对地黄发酵制备地黄酵素前后的无机元素特征进行分析,可为地黄酵素在功能性食品添加剂方面的研究和地黄酵素的制备开发提供数据支撑,测定结果稳定可靠,能满足...     

空气CH4浓度变化及其与CO的相关性

CH4是一种重要的温室气体,在空气中的含量仅次于CO2.化合物之间的相关性在化合物的浓度测量和估算等方面都有重要的意义.通过分辨率为1 cm-1的长开放光路傅里叶变换红外光谱仪测量采样路径内的北京西四环高速公路附近空气CH4和CO透过率光谱,进行非线性最小二乘光谱拟合,计算出待测组分浓度.北京秋季空气CH4浓度变化趋势几乎一样.白天的浓度变化趋势表明城市中人为活动对CH4的排放影响极大,尤其是机动车尾气的排放,而晚上浓度主要是近地面的积累.2005年9月4日到2005年9月10日的连续浓度变化表明北京秋季每天CH4和CO浓度变化趋势相同,它们的浓度变化具有一定的相关性.     

南瓜多糖的测定及南瓜多糖与口感性状相关性的研究

用苯酚-硫酸法测定了96个南瓜品种中多糖的含量,品尝了各种南瓜的口感特征,研究了南瓜的口感特征和多糖含量的相关性.结果显示,不同品种的南瓜中南瓜多糖含量有较大差别,南瓜多糖的含量和南瓜口感的面度存在显著性正相关.测定结果为南瓜新品种的培育与南瓜新产品的开发提供了重要的科学依据.