We have to use some other methods to measure the luminosity or equivalently the absolute magnitude of the cepheid variable . since we can readily measure the apparent magnitude of a cepheid variable , to measure the luminosity means measuring the distance . we use some distance measurement methods , for example , parallax , to determine the relation 要弄清这个关系，我们要知道不同造父变星的光度和光变周期数据，量度光变周期当然不是问题，但要得知一颗恒星的光度，我们首先要得知它的距离，这时便须借助好像视差法等其他量度天体距离的方法。
The first section is concerned with a brief description of the content and methods of evaluation . the second section is concerned with rifr evaluation of actual developing projects : ( 1 ) their absolute magnitudes and relative order of four risks based on sensitivity analysis of risk index ; and ( 2 ) the comprehensive risk grade evaluation of rifr through integrating fuzzy subordinate function with fuzzy integrative evaluation method 首先概要地介绍了衡量项目投融资区域风险的内容与方法，接着研究项目投融资风险评价：通过选取风险变量和评价指标，结合敏感度分析进行风险大小排序，再进一步结合模糊隶属度函数和模糊评价法的运用进行项目投融资区域风险的风险等级判定。
