An important feature of the traffic in mobile networks is burstiness. Drawbacks of conventional power control algorithms for time division duplex (TDD)-code division multiple access (CDMA) systems are analyzed. A ...An important feature of the traffic in mobile networks is burstiness. Drawbacks of conventional power control algorithms for time division duplex (TDD)-code division multiple access (CDMA) systems are analyzed. A joint power control algorithm based on service factor is presented to address the TDD-CDMA mobile services in the burst mode according to the Markov modulated Bernoulli process. The joint power control equation is derived. A function model is developed to verify the new algorithm and evaluate its performance. Simulation results show that the new power control algorithm can estimate interference strength more precisely, speed up convergence of power control, and enhance power efficiency and system capacity. It is shown that the proposed algorithm is more robust against link gain changes, and outperforms the reference algorithms.展开更多
Linux支持管道和 System V IPC等多种进程间通信机制 ,现有的进程间通信机制存在着访问控制上的缺陷 ,可能会让攻击者获得部分或全部的系统控制权。分析了现有 Linux几种进程间通信的访问控制机制 ,并提出了通过实现进程间通信的强制访...Linux支持管道和 System V IPC等多种进程间通信机制 ,现有的进程间通信机制存在着访问控制上的缺陷 ,可能会让攻击者获得部分或全部的系统控制权。分析了现有 Linux几种进程间通信的访问控制机制 ,并提出了通过实现进程间通信的强制访问控制 MAC( Mandatory Access Control)来提高展开更多
为解决航空制造企业制造过程信息安全管理困难的问题,在综合分析飞机制造过程对身份认证和访问控制需求的基础上,应用单点登录及访问控制技术,构建了面向飞机制造全过程的统一用户管理体系。该体系包括了统一身份认证管理系统和统一访...为解决航空制造企业制造过程信息安全管理困难的问题,在综合分析飞机制造过程对身份认证和访问控制需求的基础上,应用单点登录及访问控制技术,构建了面向飞机制造全过程的统一用户管理体系。该体系包括了统一身份认证管理系统和统一访问控制管理系统。重点对基于单点登录的统一身份认证策略和基于规则-任务-角色的统一访问控制策略(Rule-Task-Role Based Access Control,RTR-BAC)进行了详细地探讨,并在此基础上建立了统一用户管理信息模型。统一用户管理体系将分散的用户管理功能从各应用系统中独立出来,形成统一可配置的用户管理模块,实现了对飞机制造过程用户信息的统一管理。展开更多
基金Project supported by the National Science Foundation for Creative Research Groups (Grant No.60521002), and the National Key Technologies R&D Program (Grant No.2005BA908B02)
文摘An important feature of the traffic in mobile networks is burstiness. Drawbacks of conventional power control algorithms for time division duplex (TDD)-code division multiple access (CDMA) systems are analyzed. A joint power control algorithm based on service factor is presented to address the TDD-CDMA mobile services in the burst mode according to the Markov modulated Bernoulli process. The joint power control equation is derived. A function model is developed to verify the new algorithm and evaluate its performance. Simulation results show that the new power control algorithm can estimate interference strength more precisely, speed up convergence of power control, and enhance power efficiency and system capacity. It is shown that the proposed algorithm is more robust against link gain changes, and outperforms the reference algorithms.
基金国家高技术研究发展计划(863)(the National High-Tech Research and Development Plan of China under Grant No.2004AA413020-2)
文摘为解决航空制造企业制造过程信息安全管理困难的问题,在综合分析飞机制造过程对身份认证和访问控制需求的基础上,应用单点登录及访问控制技术,构建了面向飞机制造全过程的统一用户管理体系。该体系包括了统一身份认证管理系统和统一访问控制管理系统。重点对基于单点登录的统一身份认证策略和基于规则-任务-角色的统一访问控制策略(Rule-Task-Role Based Access Control,RTR-BAC)进行了详细地探讨,并在此基础上建立了统一用户管理信息模型。统一用户管理体系将分散的用户管理功能从各应用系统中独立出来,形成统一可配置的用户管理模块,实现了对飞机制造过程用户信息的统一管理。