Piantanelli L, Scerre F, Cognini G, Linari G
Arch Gerontol Geriatr. 1986 Jul;5(2):119-30. doi: 10.1016/0167-4943(86)90015-4.
Procedures for the estimation of the four parameters of a new mathematical model of survival and mortality kinetics are given. A formulation of the model has been found which had the advantage of maintaining three of four parameters independent of the unit chosen for the age; in addition, two of these parameters have values falling in a narrow range, even when the model is applied to rather different curves. Since, in any problem of this type, the initial estimate of the parameters plays a major role in the achievement of good final estimates, some simple methods of estimation are indicated based upon the characteristics of the function. The initial estimates may enter three different types of procedures; the best one can be chosen according to the precision of the initial estimates. The method is capable of fitting both survivorship and dying functions directly to the empirical data. An interactive approach to the computer facilities has been used as at each step the operator has to decide whether or not to apply a corrective factor. Goodness of fit, usually high, is estimated by chi 2 test.
给出了一种新的生存和死亡动力学数学模型四个参数的估计方法。已找到该模型的一种公式化表述，其优点是四个参数中的三个与所选年龄单位无关；此外，即使将该模型应用于相当不同的曲线，其中两个参数的值也落在较窄范围内。由于在任何此类问题中，参数的初始估计在获得良好的最终估计中起着主要作用，基于函数的特性给出了一些简单的估计方法。初始估计可能会进入三种不同类型的程序；可以根据初始估计的精度选择最佳的一种。该方法能够将生存函数和死亡函数直接拟合到经验数据。采用了一种与计算机设施的交互式方法，因为在每一步操作员都必须决定是否应用校正因子。拟合优度通常较高，通过卡方检验进行估计。
