A <Emphasis Type="Italic">K</Emphasis> self-adaptive SDN controller placement for wide area networks

As a novel architecture, software-defined networking (SDN) is viewed as the key technology of future networking. The core idea of SDN is to decouple the control plane and the data plane, enabling centralized, flexible, and programmable network control. Although local area networks like data center networks have benefited from SDN, it is still a problem to deploy SDN in wide area networks (WANs) or large-scale networks. Existing works show that multiple controllers are required in WANs with each covering one small SDN domain. However, the problems of SDN domain partition and controller placement should be further addressed. Therefore, we propose the spectral clustering based partition and placement algorithms, by which we can partition a large network into several small SDN domains efficiently and effectively. In our algorithms, the matrix perturbation theory and eigengap are used to discover the stability of SDN domains and decide the optimal number of SDN domains automatically. To evaluate our algorithms, we develop a new experimental framework with the Internet2 topology and other available WAN topologies. The results show the effectiveness of our algorithm for the SDN domain partition and controller placement problems.     

基于发布订阅的分布式监控主动消息交互研究

针对分布式调度监控系统的客户服务器处理效率不高的问题,利用发布订阅消息通信技术,结合公共信息模型,提出了一种分布式监控主动消息交互的新方法;对量测类信息流和控制类信息流进行了实时交互接口设计,融入JMS消息服务器消息主题和发布订阅传输交互模式;该方法在工程中进行了应用,以石德线为算例,进行模拟量和状态量信息的交互实验,完成了单点和多点信息的交互传输,实现了实时变位信息向监控画面的主动即时传输,为分布式调度监控处理提供了一种新的高效实现方法.     

基于WSN的核辐射监测系统路由算法研究

由于核辐射环境的特殊性及无线传感器网络传感器节点能量的有限性,在LEACH协议的基础上提出一种路由改进算法,考虑节点的剩余能量、位置信息及节点到基站的距离等因素,改进适应值函数,利用粒子群优化算法,选取簇头节点。簇头节点选取合适的路径以单跳或多跳的传输方式与汇聚节点通信。仿真结果表明,改进算法明显地节省了节点能量,有效地延长了整个网络的生存周期,使得基于无线传感器网络的核辐射监测系统具有高效、稳定和实时监测的功能。     

基于移动社交群的互联网内容适配系统的搭建

基于移动社交群,提出了一种面向群体推荐互联网内容的系统。这种面向社交群体的新精确营销模式不仅能提升营销效率,也减少了客户接触频次,提升了客户感知。     

嵌入式PLC应用前景的研究

随着经济的快速发展和科学技术的不断进步,工业控制产品已发展到一个追求个性化、差异化的阶段.传统的PLC产品已经无法满足更加细分化的市场需求,为了满足这种需求,嵌入式PLC作为工业控制产品的新方向便应运而生.本文在对当前PLC技术和嵌入式技术的研究基础上,将从工业控制的应用需要出发,通过对嵌入式软PLC系统相关技术的优缺点和国内外PLC发展现状的分析研究,得出嵌入式PLC的未来发展趋势,为以后嵌入式PLC的研究提供一定的有益经验.     

浅析移动通信业务安全

本文从安全服务运营管理角度出发探讨了当前移动通信业务开展中面临的各项安全成胁,并提出了移动通信业务的安全应用策略,对促进移动业务实现高质、高效、安全、持续的服务有重要的推进作用.     

Post-buckling dynamic behavior of self-assembled 3D microstructures

The paper presents the snap-through phenomenon in the case of micro fabricated clamped-clamped buckled beam. This dynamic post-buckling behavior is likely to occur in 3D microstructures when they are subjected to large vibration amplitudes. The main difference between this work and previous studies is the MEMS specific beam dimension, especially the large initial deflection of the buckled beam that involves the inversion of the two first resonance frequencies. The mathematical development allows showing how the vibration amplitude of the supporting base affects the post-buckling dynamic behavior of the beam. For each frequency, the limit between the stable behavior and the snap-through behavior is evaluated. Moreover, the effect of environment is taken into account from the damping point of view. Samples are fabricated and the experiment is described. Measurements are compared to the theoretical approach and the results are in good agreement with the proposed model.     

基于最小二乘自适应迭代的宽带波束形成算法

大部分时域恒定束宽宽带波束形成算法的权值拟合运算量较大,导致实用性大大降低.本文给出一种基于最小二来自适应迭代的恒定束宽波束形成器设计方法,同时将RLS迭代算法应用于滤波器组设计中.本文方法易于实现,不受阵形及阵元指向性限制,不受迭代步长影响,且能快速收敛.理论推导及仿真实验验证了本文方法的有效性.