Stress field near interface edge of elastic-creep bi-material

Stress fields on elastic-creep bi-material interfaces with different geometry of the interface edge are analyzed by finite element method. The results reveal that the stress highly concentrates near the interface edge at the loading instant and it gradually decreases as the creep-dominated zone expands from the small-scale creep to the large-scale creep. The stress singularity due to creep which resembles the HRR stress singularity appears near the interface edge in all cases. The stress intensity near the interface edge time-dependently decreases and becomes constant when the transition reaches the steady state. The magnitude is scarcely influenced by the edge shape of elastic material, though it depends on the edge shape of creep material. The stress intensity during the transition can be approximately predicted by the J-integral at the loading instant.     

空分设备主换热器增压通道冰堵故障分析及处理

由于膨胀机增压端后冷却器内漏,30000 m3/h空分设备在临时停车再开车时出现了主换热器增压通道阻力增大现象。采取临时停车对增压通道进行局部加温的方法未能排除故障,后启动空压机,对主换热器部位进行加温解冻才解决问题。简介主换热器增压通道冰堵后的参数变化情况,介绍堵塞通道解冻的具体过程。     

城区复杂环境213t炸药大区深孔爆破技术

介绍了城区复杂环境大区露天深孔爆破技术在牛头山剩余山体爆破工程中的应用。工程采用复杂环境大区深孔毫秒延时、逐孔起爆的一次性爆破方案。爆区预处理技术创造了良好的自由面,优质的爆破器材、合理的毫秒延时时间及可靠的网路搭桥技术,精心的施工组织及充分的爆前准备确保了爆破效果及施工过程的高质量、高效率、安全有序。该项爆破技术具有对周边居民及有关单位生活、工作影响程度最低,施工周期短、综合效益好的优点,对类似工程具有借鉴意义。     

Connectability and structural controllability of composite systems

The notion of connectability for multivariable composite systems consisting of a number of subsystems interconnected in an arbitrary way is introduced in this paper. It is shown that connectability plays a fundamental role in composite systems; in particular, it is shown that under certain mild conditions, almost all composite interconnected systems are controllable and observable from any nontrivial input and output if and only if the resultant composite system is connectable. A class of composite systems called general input-output hierarchical systems, which has the property of always being connectable is then defined. Since such systems are almost always controllable, this observation perhaps gives some insight in explaining why so many real world systems have as their basis a hierarchical structure. An application of the previous results is then made to show that a system (C, A, B) is structurally controllable and observable if and only if it is connectable and a certain non-pathological rank condition holds.     

DIDAPPER:具有认知能力的分布式入侵检测系统

近年来,随着网络安全问题日益突出,入侵检测也越来越受到关注。目前,研究入侵检测的课题很多,侧重点也各不相同。该文介绍的ＤＩＤＡＰＰＥＲ系统是一种具有认知能力的分布式入侵检测系统。分布式结构、认知能力和知识的共享是ＤＩＤＡＰＰＥＲ系统的重要特点。流量标本和ＩＰ陷阱是ＤＩＤＡＰＰＥＲ系统所提出的新概念。ＤＩＤＡＰＰＥＲ的分布式三级结构使得它适合于检测大规模网络自动攻击行为,而且有较强的可扩展性和高效性。     

离散大系统存在未模化动力学时的分散自适应控制

本文研究了离散大系统存在未模化动力学时的分散模型参考自适应控制问题。对以状态变量和输入-输出变量设计的自适应系统,得到了复合闭环系统的所有信号及跟踪误差将收敛并保持在一有界集的充分条件。     

A global piecewise smooth Newton method for fast large-scale model predictive control

In this paper, the strictly convex quadratic program (QP) arising in model predictive control (MPC) for constrained linear systems is reformulated as a system of piecewise affine equations. A regularized piecewise smooth Newton method with exact line search on a convex, differentiable, piecewise-quadratic merit function is proposed for the solution of the reformulated problem. The algorithm has considerable merits when applied to MPC over standard active set or interior point algorithms. Its performance is tested and compared against state-of-the-art QP solvers on a series of benchmark problems. The proposed algorithm is orders of magnitudes faster, especially for large-scale problems and long horizons. For example, for the challenging crude distillation unit model of Pannocchia, Rawlings, and Wright (2007) with 252 states, 32 inputs, and 90 outputs, the average running time of the proposed approach is 1.57 ms.     

Spark平台上利用网络加权Voronoi图的分散迭代社区聚类并行化研究

针对当下数据大规模增长对计算能力需求的急剧增长,传统独立运行的机器在大规模网络社区中执行社区检测操作时无法提供所需的数据处理能力的问题,提出一种网络加权Voronoi图的并行分散迭代社区聚类法(NWVD-PDICCM).利用基于网络加权Voronoi图的分散迭代社区聚类方法(NWVD-DICCM)提取大型网络的有效社区...     

Robust decentralized stabilization of Markovian jump large-scale systems: A neighboring mode dependent control approach

This paper is concerned with the decentralized stabilization problem for a class of uncertain large-scale systems with Markovian jump parameters. The controllers use local subsystem states and neighboring mode information to generate local control inputs. A sufficient condition involving rank constrained linear matrix inequalities is proposed for the design of such controllers. A numerical example is given to illustrate the developed theory.