The paper addresses the issue of H_∞ couple-group consensus for a class of discrete-time stochastic multi-agent systems via output-feedback control. Both fixed and Markovian switching communication topologies are con...The paper addresses the issue of H_∞ couple-group consensus for a class of discrete-time stochastic multi-agent systems via output-feedback control. Both fixed and Markovian switching communication topologies are considered. By employing linear transformations, the closed-loop systems are converted into reduced-order systems and the H_∞ couplegroup consensus issue under consideration is changed into a stochastic H_∞ control problem. New conditions for the mean-square asymptotic stability and H_∞ performance of the reduced-order systems are proposed. On the basis of these conditions, constructive approaches for the design of the output-feedback control protocols are developed for the fixed communication topology and the Markovian switching communication topologies, respectively. Finally, two numerical examples are given to illustrate the applicability of the present design approaches.展开更多
Network security protocols such as IPsec have been used for many years to ensure robust end-to-end communication and are important in the context of SDN. Despite the widespread installation of IPsec to date, per-packe...Network security protocols such as IPsec have been used for many years to ensure robust end-to-end communication and are important in the context of SDN. Despite the widespread installation of IPsec to date, per-packet protection offered by the protocol is not very compatible with OpenFlow and tlow-like behavior. OpenFlow architecture cannot aggregate IPsee-ESP flows in transport mode or tunnel mode because layer-3 information is encrypted and therefore unreadable. In this paper, we propose using the Security Parameter Index （SPI） of IPsec within the OpenFlow architecture to identify and direct IPsec flows. This enables IPsec to conform to the packet-based behavior of OpenFlow architecture. In addition, by distinguishing between IPsec flows, the architecture is particularly suited to secure group communication.展开更多
传统的高速数据存储系统使用RAID(redundant array of independent disks)技术组建硬盘阵列以提高存储带宽与存储容量。工作过程中RAID控制器的数据分配策略、缓存性能以及单次存储操作的数据长度等因素会直接影响系统存储带宽的稳定性...传统的高速数据存储系统使用RAID(redundant array of independent disks)技术组建硬盘阵列以提高存储带宽与存储容量。工作过程中RAID控制器的数据分配策略、缓存性能以及单次存储操作的数据长度等因素会直接影响系统存储带宽的稳定性,并造成瞬时存储速度陡降。针对这一问题,提出了一种硬盘分组控制方法,该方法分为3个步骤:根据存储带宽需求组建硬盘分组;建立分组切换机制保证分组间的工作负载均衡;实时监测缓存状态,非平稳状态下当缓存长度达到安全阈值时自适应切换工作分组以保证存储系统持续稳定工作。该方法已在国家西部测绘项目实际应用并得到验证。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61503002 and 61573008)
文摘The paper addresses the issue of H_∞ couple-group consensus for a class of discrete-time stochastic multi-agent systems via output-feedback control. Both fixed and Markovian switching communication topologies are considered. By employing linear transformations, the closed-loop systems are converted into reduced-order systems and the H_∞ couplegroup consensus issue under consideration is changed into a stochastic H_∞ control problem. New conditions for the mean-square asymptotic stability and H_∞ performance of the reduced-order systems are proposed. On the basis of these conditions, constructive approaches for the design of the output-feedback control protocols are developed for the fixed communication topology and the Markovian switching communication topologies, respectively. Finally, two numerical examples are given to illustrate the applicability of the present design approaches.
文摘Network security protocols such as IPsec have been used for many years to ensure robust end-to-end communication and are important in the context of SDN. Despite the widespread installation of IPsec to date, per-packet protection offered by the protocol is not very compatible with OpenFlow and tlow-like behavior. OpenFlow architecture cannot aggregate IPsee-ESP flows in transport mode or tunnel mode because layer-3 information is encrypted and therefore unreadable. In this paper, we propose using the Security Parameter Index （SPI） of IPsec within the OpenFlow architecture to identify and direct IPsec flows. This enables IPsec to conform to the packet-based behavior of OpenFlow architecture. In addition, by distinguishing between IPsec flows, the architecture is particularly suited to secure group communication.
文摘传统的高速数据存储系统使用RAID(redundant array of independent disks)技术组建硬盘阵列以提高存储带宽与存储容量。工作过程中RAID控制器的数据分配策略、缓存性能以及单次存储操作的数据长度等因素会直接影响系统存储带宽的稳定性,并造成瞬时存储速度陡降。针对这一问题,提出了一种硬盘分组控制方法,该方法分为3个步骤:根据存储带宽需求组建硬盘分组;建立分组切换机制保证分组间的工作负载均衡;实时监测缓存状态,非平稳状态下当缓存长度达到安全阈值时自适应切换工作分组以保证存储系统持续稳定工作。该方法已在国家西部测绘项目实际应用并得到验证。
