This paper discusses the tree a core data structure of one kind of project progress management software,and the implementation and optimization of algorithms of searching and traversal. In the algorithm D&C method is used throughout the process. We also try to change method of backtracking some key nodes so as to increas the speed of traveling throughout the tree.
在实现基于角色访问控制(Role-Based Access Control，RBAC)的系统中，由于判断程序的权限仅仅根据启动该程序的角色，故一旦该程序有安全漏洞并被攻击，入侵者就会攫取该角色的全部权限进行权限滥用。该文提出程序角色(process role)的概念,并构建出动态生成程序角色的DKPRF(Double Knowledge based Process Role Frame)框架，有效地限制了RBAC中权限的滥用。
