参考论文：
Click-Through Rate Estimation for Rare Events in Online Advertising
参考的博客：
1、https://jiayi797.github.io/2017/07/09/%E6%9C%BA%E5%99%A8%E5%AD%A6%E4%B9%A0%E5%AE%9E%E8%B7%B5-%E8%BD%AC%E5%8C%96%E7%8E%87%E9%A2%84%E4%BC%B0%E4%B9%8B%E8%B4%9D%E5%8F%B6%E6%96%AF%E5%B9%B3%E6%BB%91/
2、贝叶斯参数估计 https://blog.csdn.net/jinping_shi/article/details/53444100
3、CTR平滑 介绍 https://blog.csdn.net/jinping_shi/article/details/78334362
4、工程实现的方法：https://www.cnblogs.com/bentuwuying/p/6498370.html