非线性最小二乘法分析疟疾发病率的变化趋势

应用非线性的最小二乘法的L-M算法分析全国流行性疟疾发病率随时间变化规律.结果发现:疟疾发病率呈现出大幅度的周期性变化和长期的缓慢增加.由于标准偏差较小,线性迭加二阶的傅里叶多项式可能代表疟疾发病率的真实变化规律.疟疾发病率周期性变化的周期约为1年,这与长期监测的结果相一致;而1%左右的增加率可能是由于近几年人口流动激增和严重的环境污染造成的。

Nonlinear Least -squares Method Analyzing the Trend of Malaria Incidence

Using the Levenberg-Marquardt method of the nonlinear least-squares,the incidence of the national prevalent malaria was analyzed in this paper.From the calculated results,it was discovered that there appeared to a cyclic variation with high amplitude,superimposed on a slowly secular increase for the malaria incidence.Due to a smaller standard deviation,second-order of Fourier polynomials superimposed on a linear equation may represent a genuine variable law.For the incidence of malaria,its period of cyclic oscillation was about one year,which was in agreement with the result of the secular supervision.Malaria incidence increaseed at a rate of one percent or so,which may be caused by the rapid migrant population and the serious environmental pollution.