中文摘要：

针对现有访问控制模型在工作流系统应用中存在的局限，构建了一种改进的基于任务一角色的访问控制模型．该模型结合基于角色的访问控制（RBAC）和基于任务的访问控制（TBAC）模型的优点，按现实需求分别对角色和任务进行分类，在保证系统安全性的同时降低了访问策略的复杂性．以远程稿件处理系统为例，讨论了该模型在实际应用中的有效性．

英文摘要：

Existing access control models cannot satisfy all the characteristics in the application of workflow systems. To address this issue, an improved access control model based on task-role is put forward. The new model which classifies roles and tasks according to practical requirements, integrates the strong points of role-based access control model （RBAC） and task-based access control model （TBAC）. It is specified that the proposed model lowers the complexity of access strategy and ensures the security as well. A remote paper disposal system is described to illustrate the validity of the model.