Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems. But when intrusions occur, traditional quorum systems have some disadvantages. For example, synchronous qu...Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems. But when intrusions occur, traditional quorum systems have some disadvantages. For example, synchronous quorum systems are subject to DOS attacks, while asynchronous quorum systems need a larger system size （at least 3f＋1 for generic data, and f fewer for self-verifying data）. In order to solve the problems above, an intrusion-tolerance quorum system （ITQS） of hybrid time model based on trust timely computing base is presented （TTCB）. The TTCB is a trust secure real-time component inside the server with a well defined interface and separated from the operation system. It is in the synchronous communication environment while the application layer in the server deals with read-write requests and executes update-copy protocols asynchronously. The architectural hybridization of synchrony and asynchrony can achieve the data consistency and availability correctly. We also build two kinds of ITQSes based on TTCB, i.e., the symmetrical and the asymmetrical TTCB quorum systems. In the performance evaluations, we show that TTCB quorum systems are of smaller size, lower load and higher availability.展开更多
在不可靠信任环境下,考虑设备到设备(Device-to-Device,D2D)辅助边缘计算中的时效性问题,针对多用户单服务器的场景,基于用户间社会关系与交互行为,构建端到端信任模型及联合服务缓存和卸载决策优化模型,以最小化平均响应时延;提出基于...在不可靠信任环境下,考虑设备到设备(Device-to-Device,D2D)辅助边缘计算中的时效性问题,针对多用户单服务器的场景,基于用户间社会关系与交互行为,构建端到端信任模型及联合服务缓存和卸载决策优化模型,以最小化平均响应时延;提出基于信任的服务缓存及卸载(Trust-based Service Caching and Task Offloading,TCO)算法,将原问题分解为多个子问题,将服务缓存子问题转换为背包问题,使用动态规划法进行求解,将D2D中继选择子问题建模为最短路径问题,使用Dijkstra算法求解,采用轮询比较方式完成最终的卸载策略。实验仿真验证了所提算法能够有效提高缓存命中率,降低用户响应时延,保障系统的时效性。展开更多
基金supported by the National Natural Science Foundation of China (60774091)
文摘Quorum systems have been used to solve the problem of data consistency in distributed fault-tolerance systems. But when intrusions occur, traditional quorum systems have some disadvantages. For example, synchronous quorum systems are subject to DOS attacks, while asynchronous quorum systems need a larger system size （at least 3f＋1 for generic data, and f fewer for self-verifying data）. In order to solve the problems above, an intrusion-tolerance quorum system （ITQS） of hybrid time model based on trust timely computing base is presented （TTCB）. The TTCB is a trust secure real-time component inside the server with a well defined interface and separated from the operation system. It is in the synchronous communication environment while the application layer in the server deals with read-write requests and executes update-copy protocols asynchronously. The architectural hybridization of synchrony and asynchrony can achieve the data consistency and availability correctly. We also build two kinds of ITQSes based on TTCB, i.e., the symmetrical and the asymmetrical TTCB quorum systems. In the performance evaluations, we show that TTCB quorum systems are of smaller size, lower load and higher availability.
文摘在不可靠信任环境下,考虑设备到设备(Device-to-Device,D2D)辅助边缘计算中的时效性问题,针对多用户单服务器的场景,基于用户间社会关系与交互行为,构建端到端信任模型及联合服务缓存和卸载决策优化模型,以最小化平均响应时延;提出基于信任的服务缓存及卸载(Trust-based Service Caching and Task Offloading,TCO)算法,将原问题分解为多个子问题,将服务缓存子问题转换为背包问题,使用动态规划法进行求解,将D2D中继选择子问题建模为最短路径问题,使用Dijkstra算法求解,采用轮询比较方式完成最终的卸载策略。实验仿真验证了所提算法能够有效提高缓存命中率,降低用户响应时延,保障系统的时效性。
