算术几何平均

The concept of the weighted logarithmic power mean is introduced; its relation with two-parameter mean is given; the inequality for weighted logarithmic power mean is derived; the magnitude relation among upper bounds of geometric mean and arithmetic mean of geometrically convex functions are made certain.

建立了几何凸函数的对称拟算术平均不等式，对文献[1]提出的不等式进行了推广统一；引进加权对数幂平均的概念，建立起其与双参数平均之间的关系，得到加权对数平均不等式，从而确定了几何凸函数的几何平均、算术平均的上界的大小关系；最后，提出了几何凸函数的对称拟算术平均不等式的推广问题。

The numerical results also indicate that the weighted geometric mean method needs less number of iteration than the weighted arithmetic mean method.

数值结果也显示：加权几何平均法所需的迭代次数比加权算术平均法所需迭代次数少。

On the aspect of error compensation, the system using the geometric average sound pressure instead of the arithmetic average sound pressure to get the sound pressure of the measurement point. This method not only reduces the high frequency error in the sound intensity measurement, which compensates the finite difference approximation error, but also greatly reduces the computation of the sound pressure spectrum.

误差补偿方面，课题采用几何平均声压代替通常的算术平均声压来计算双传声器法的声场声压值，这样不仅可以有效的减少声强测量中的高频误差，对有限差分误差起到了补偿作用，而且还大大减小了声压谱计算中的计算量。

There are two means to measure the average prices of the assets in an Asian option theoretically:with the arithmetic average and with the geometric average.

亚式期权有两种理论上的表示方式，即采用算术平均法计算资产价格的平均值和采用几何平均法计算资产价格的平均值。

In this paper we considered three problems on Asian options pricing: The valuation of geometric average Asian options with stochastic averaging period, the valuation of Asian options with fixed strike price and floating strike price in the case of arithmetic average.

本文考虑了三个关于亚式期权的定价问题：平均周期是随机的几何平均亚式期权的定价；具有固定执行价格的算术平均亚式期权的定价和具有浮动执行价格的算术平均亚式期权的定价。

The main results are as follows:We review the existing Monte Carlo control variates estimators of the price of Asian options and propose a new one. According to pratical needs, we define efficiency as the inverse of the product of the variance of an estimator and its computational time and make it a standard for comparisons to draw the following conclusions: Firstly, the more control variates correlate with arithmetic average Asian options, the larger is the efficiency of an estimator with these control variates, but among which the geometric average option plays the most important role; Secondly, an estimator with more control variates is better than one with less ones only when the time to maturity is long and the volatility is high.

在综合已有研究工作的基础上，本论文的主要创新成果如下：（1）我们回顾了已有的亚洲期权价格的蒙特卡罗控制变量估计，并提出了一个新的控制变量估计，且从客观实际出发，将估计值的方差和计算时间的乘积的倒数定义为效率并以它为标准比较各估计，得到以下结论：与算术平均亚洲期权相关程度越大的控制变量构成的估计的效率越大，而其中起主要作用的控制变量为几何平均亚洲期权的价格；只有在到期时间较长且标的资产的波动率较大时，元素多的多元控制变量估计比元素少的效率大。

4Based on a fact that the price formula of Asian options can be transformed into that of vanilla European option when the time to maturity is less than or equal to the length of average, we skillfully obtain the analytical price formula for the option on the minimum or the maximum of two geometric average prices and generalize it to obtain the price formula of several average prices for the first time. We also apply the method of [121], which approximates the arithmetic average by the geometric average, to the pricing of opitons on the minimum or the maximum of two arithmetic average prices to obtain Its approximated price formula. Numerical results show that the approximated price is relatively accurate when the riskless interest rate is large or the option is in the money and the volatility of two underlying assets are high and its accuracy is a little reduced but still good when the dividends are considered. However, it is hardly affected by the sampling number.

我们基于观察到的一个事实即当离到期时间小于或等于平均期间时亚洲期权的价格可变换成普通的欧式期权的价格，从而巧妙地得到了两个几何平均价格的最小或最大值期权价格的解析公式，通过简单地推广，首次得到了多个几何平均时的价格公式；将[121]用于算术平均亚洲期权的定价方法推广到两个算术平均价格的最小或最大值期权，从而得到它的渐进公式，数值结果表明：渐进价格的准确性在无风险利率较大或期权为实值且两标的资产的波动率较小时较好，抽样的个数对它没有影响，但考虑红利时它稍有下降但仍较好。

Two amelioration operators were developed, such as the triangular intuitionistic fuzzy numbers weighted arithmetic average operator, and the f interval-valued intuitionistic fuzzy numbers weighted geometric average operator.

定义了三角和区间直觉模糊集的一些运算法则，给出了直觉模糊集两个改进算子，即三角模糊数加权算术平均算子和区间直觉模糊数加权几何平均算子。

The algorithms are respectively to compute arithmetic mean of the probabilities and normalized geometric mean of the probabilities.

采用公理化方法给出了相应的算法，这两个算法算法分别是对概率进行算术平均和几何平均，再进行归一化处理。

The research for the means has a long history, the classical means include algebraic mean, geometric mean and harmonic mean etc.

平均数理论研究的历史久远，经典的平均数包括算术平均，几何平均，调和平均等。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。