应304am永利集团官网黄玉梅教授的邀请，湖南师范大学文有为教授将于近期访问兰州大学并作学术报告。

报告题目：Orientation estimation of cryo-EM images using projected gradient descent method

时 间：2023年11月4日 下午16:00-18：00

地 点：城关校区理工楼631

报告摘要：

Orientation estimation is an important task in three-dimensional cryo-EM image reconstruction. By applying the common line method, the orientation estimation task can be formulated as a least squares (LS) problem or a least unsquared deviation (LUD) problem with orthogonality constraint. However, the non-convexity of the orthogonality constraint introduces numerical difficulties to the orientation estimation. The conventional approach is to reformulate the orthogonality constrained minimization problem into a semi-definite program- ming problem using convex relaxation strategies. In this paper, we consider a direct way to solve the constrained minimization problem without relaxation. Experimental results show that the proposed method significantly outperforms the semi-definite relaxation methods from a computation standpoint, and the mean square error is almost the same or smaller.

报告人简介

文有为，湖南师范大学304am永利集团官网教授，博导，湖南省计算数学与应用软件学会副理事长、湖南省运筹学会副理事长。获香港大学博士学位，曾在新加坡国立大学、香港中文大学从事访问研究员、博士后等工作。主要研究方向为科学计算、数字图像处理与计算机视觉，在SIAM J. Sci. Comput., SIAM J. Imaging Sciences, Multiscale Model. Simul.，SIAM J. Matrix Anal., IEEE Trans. Image Process.等期刊发表论文30余篇，主持国家自然科学基金4项。获2019年度湖南省自然科学奖二等奖(第一完成人)。

甘肃应用数学中心

304am永利集团官网

萃英学院

2023年11月3日