Three-dimensional CAD is the foundation of digital design, manufacturing and management and the core tools of modern product innovation. This article provided a brief introduction on three-dimensional CAD technology and its prospects and elaborated the significance of mastering three-dimensional CAD technology and technological innovation for modem engineer.%针对企业级信息系统用户、角色多,权限关系和客体资源复杂等特点,在分析了多种访问控制技术的基础上,提出了一种新的基于角色的访问控制模型及其安全策略.此模型对传统的RBAC模型进行了优化处理,将分级授权、最小化授权、角色授权继承等策略相结合,以支持多种细粒度的访问控制.实验证明,能提高企业级信息系统的安全性和运行效率.
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