The concept of assignment state sace was proposed and a network teaching management model, NERAT (network teaching role-assignment-task) model, was built based on these definitions.

• 该模型具有以学生为中心、以作业任务驱动的多角色互动的特点，并提供了基于角色的个性化反馈以及基于作业文档集的学习、教学和多元等4种不同层次的反馈策略。