Abstract
We have already developed an annotation writing and sharing system for web-based learning materials. This system allows learners to write annotations such as markers and memorandums directly on materials, and share these annotations among lecturers and learners. If necessary, web-based materials can often be updated by authors; however, the annotations on the material are not in the proper position after the update. In the present study, we propose a method for realigning annotations to their proper position in updated materials, and conduct experiments to evaluate the method. The following paper describes the proposed method and the experimental evaluation.