A quick Google search returns a number of results with purported fixes - some of which are below:
- http://bgr.com/2014/10/27/experiencing-wi-fi-issues-in-yosemite-heres-how-to-fix-them-yourself/
- http://www.digitaltrends.com/computing/os-x-yosemite-wi-fi-bugs-reported-no-universal-fix-out-yet/
- http://osxdaily.com/2014/10/25/fix-wi-fi-problems-os-x-yosemite/
Students and faculty experiencing WIFI issues after upgrading to Yosemite should report the issue to its@manhattan.edu as well as contact Apple support http://support.apple.com/kb/HT4628
