Chang is currently the dean of the School of Engineering and Applied Science of Columbia University, where he is also the Morris A. and Alma Schapiro Professor.
The primary focus of his work is on development of intelligent methods and systems for extracting information from visual content and multimedia that are prevalent in large archives and live sources.
In the early 1990s, his group developed some of the earliest and best-known content-based image search systems, VisualSEEk and VideoQ,[7][8] which set the foundation of this vibrant area.
[15][16] In addition, he has developed a series of fundamental methods of graph-based semi-supervised learning[17][18] that successfully address the challenge of training large-scale multimedia retrieval systems with noisy and sparse labels.
The graph-based search process, based on the random walk with restart theory, developed jointly with X. Wu and Z. Li, has also been deployed in the large app recommendation system of Huawei (more than 300 million users).