This is an online publication. It surveys the field of semi-supervised learning, a branch under machine learning and more generally artificial intelligence. It originates as a chapter from the author's Ph.D. thesis. The survey is updated regularly to incorporate latest developments in the field. Please use the "Download the latest survey" link above to get the most recent version. The version number is the "Last Modified on" date under the title in each pdf file. Please cite the survey in your work as recommended in Section 1 of the survey. Older versions are kept for citation purpose too. Your comments are highly welcome to help me eliminate errors and add in new materials. Please send email to jerryzhu@cs.wisc.edu.
You may find my book Introduction to Semi-Supervised Learning useful too.
Xiaojin Zhu
Computer Science Department
University of Wisconsin, Madison