中文摘要：

网格体系结构中最重要的是中间层——虚拟资源层，该文提出一种改进的基于虚拟组织的网格体系结构，通过对虚拟组织进行抽象、规划及相应的映射，使网格资源具有易查找和易管理的特点，在映射资源的同时映射该资源的访问控制权限，由资源的拥有者界定资源的安全策略，从而增强网格系统的安全性。分析和给出了该模型的安全性和访问控制过程。

英文摘要：

The middle layer is virtual resource layer. It plays a crucial role in grid architecture. A modified access control model based on virtual organization in grid is proposed. It makes grid resource more administrable and more convenient to lookup based on abstracting and programming virtual organizations and corresponding mapping rules. The security policies of the resource are mapped while the resource is mapped to the virtual organization. The owner of the resource determines the security policies of the resource, which strengthens the safety of the grid.