Cross-platform annotation development for real-time collaborative learning

For remote learners, collaborative editing of digital learning documents is a productive and powerful mechanism to add valued information, share ideas, and create knowledge. One such collaborative editing mechanism is adding annotations, which assists knowledge sharing and deep learning in learners. The Portable Document Format (PDF), despite its popularity, has limited support for real-time collaborative annotations. This is due to the lack of tools as well as limitations in existing standards for annotation representation in PDF documents. For example, existing collaborative PDF editing platforms do not support all annotation types and the latency of annotation sharing is high. The present study aims to fill this gap in annotation representation models and proposes a novel architecture to facilitate efficient sharing of annotations. We also describe our prototypical implementation of a collaborative editing platform for PDF annotations. It supports more annotation types and shows lower latency compared to Acrobat PDF reader version 2020.013.20074 and Kami PDF editor.