Xiaojun Bi

Xiaojun Bi
Assistant Professor

Department of Computer Science
Room 161
Stony Brook, NY 11794-2424

(631) 632-2506
xiaojun [at] cs.stonybrook.edu


Human Computer Interaction, Mobile Computing, Interactive Systems, Interaction Techniques, Theoretical Issues of UI Design.


Xiaojun Bi received his Ph.D. from the Computer Science Department at University of Toronto in 2011. 


Xiaojun Bi research lies in the general area of Human Computer Interaction, with a primary focus on building interactive systems, designing interaction techniques, and studying fundamental issues of user interface design on mobile devices. One of his main research directions is improving text entry in mobile computing. He has contributed a number of innovations in this area, including bimanual gesture typing, optimizing the keyboard decoding algorithm for both correction and completion abilities, optimizing keyboard layouts, personalizing language models, and building automatic keyboard evaluation systems. His other main research is in the design of new interactive systems and input techniques with emerging input modalities. Some major projects include Magic Desk (a desktop computing environment enhanced with multi-touch capabilities), Gather Reader (an e-reader with pen and multi-touch input), WallTop (a multi-window based, large display window management system prototype), and pen rolling & tilting interaction techniques. Establishing robust laws and regularities is fundamental to a research field. This is increasingly important in HCI as new input modalities are emerging. His research in this area includes deriving the Finger-Fitts Law (i.e., FFitts Law) to specify the speed-accuracy tradeoff of touch input, and deriving the Bayesian Touch Criterion as a principled approach of ranking target likelihood in target acquisition tasks.


ACM CHI 2017 Honorable Mention Award (Top 5%); ACM CHI 2015 Honorable Mention Award (Top 5%); ACM CHI 2011 Honorable Mention Award (Top 5%); 2013 Google Influential Paper Award; First place in National Mathematic Contest (China) in Yunnan province, recruited by Tsinghua University with National Entrance Examinations waived.

Teaching Summary