Low Pass metallic mesh interference filters for operation in the 165 GHz to 880 GHz region

Low Pass metallic mesh interference filters have been designed and constructed for operation in the region 340 m (880 GHz) to 1.8 mm (165 GHz). These filters have been shown to have excellent edge characteristics and good rejection regions. The results show that the mesh filter can be effectively used in both millimetre and submillimetre regions.Part of this work was performed while this author was at Heriot-Watt University, Edinburgh, U.K.     

单重工作休假M/M/c排队驱动的流体模型分析

该文在M/M/c排队驱动系统中加入工作休假策略,研究了单重工作休假多服务台排队驱动的流体模型.利用拟生灭过程和矩阵几何解法得到驱动系统稳态队长分布.构建净输入率结构,导出流体模型的稳态联合分布函数满足的的矩阵微分方程组,进而利用Laplace-Stieltjes变换(LST)方法得到稳态下缓冲器库存量的空库概率及均值表...     

OTN电交叉技术及组网应用分析

光传送网（OTN）技术正逐步取代SDH／MSTP、WDM技术,成为光传送网主流技术。本文在对OTN电交叉技术和设备以及国内运营商网络业务需求特点进行深入分析的基础上,提出了采用OTN电交叉技术组建环形网和网状网的建设方案。     

一种新的WLAN无线Mesh网络测试床的设计与实现

研究了现有的Mesh网络测试床,针对关键节点网络接入点（MAP）的设计,提出“分而治之”的思想,将MAP的功能分解到接入点（AP）和网格点（MP）分别实现,并引入第三大功能子网。该方案在网卡的选择、节点故障处理及后期网络的扩展性等方面很好地弥补了采用单一节点模拟方案的局限性。方案的实现表明改进后的测试床具有易搭建、易维护和易扩展的特点。     

无线Mesh网络可扩展性相关技术

无线移动通信中传输的数据密度持续增长对无线Mesh网络的系统性能提出了挑战。在无线自组织网络中,由于存在随着节点数目的增加而平均节点容量逐步降低的规律,因此无线Mesh网络的大规模组网难以实施。无线Mesh网络可扩展性对于增强无线Mesh网络的自适应组网能力至关重要,因此,文章对在Mesh基站和Mesh移动台上采用的与可扩展性相关的关键技术,如信道分配技术、智能路由技术、多天线技术、节点分类和QoS分级技术、协作传输技术等,进行了探讨。     

WLAN技术与应用发展新趋势

提出WLAN的技术热点主要集中在VoWLAN,Mesh Wi-Fi和802.11n三个方面.具体阐述了VoWLAN和Mesh Wi-Fi的标准化进展、终端商用化进展以及对通信产业的影响.展望了VoWLAN和MeshWi-Fi的发展形势和机遇,分析了其面临的挑战.     

A resource-efficient and scalable wireless mesh routing protocol

By binding logic addresses to the network topology, routing can be carried out without going through route discovery. This eliminates the initial route discovery latency, saves storage space otherwise needed for routing table, and reduces the communication overhead and energy consumption. In this paper, an adaptive block addressing (ABA) scheme is first introduced for logic address assignment as well as network auto-configuration purpose. The scheme takes into account the actual network topology and thus is fully topology-adaptive. Then a distributed link state (DLS) scheme is further proposed and put on top of the block addressing scheme to improve the quality of routes, in terms of hop count or other routing cost metrics used, robustness, and load balancing. The network topology reflected in logic addresses is used as a guideline to tell towards which direction (rather than next hop) a packet should be relayed. The next hop is derived from each relaying node’s local link state table. The routing scheme, named as topology-guided DLS (TDLS) as a whole, scales well with regard to various performance metrics. The ability of TDLS to provide multiple paths also precludes the need for explicit route repair, which is the most complicated part in many wireless routing protocols. While this paper targets low rate wireless mesh personal area networks (LR-WMPANs), including wireless mesh sensor networks (WMSNs), the TDLS itself is a general scheme and can be applied to other non-mobile wireless mesh networks.     

Geometrically nonlinear analysis with a 4-node membrane element formulated by the quadrilateral area coordinate method

Recently, a 4-node quadrilateral membrane element AGQ6-I, has been successfully developed for analysis of linear plane problems. Since this model is formulated by the quadrilateral area coordinate method (QACM), a new natural coordinate system for developing quadrilateral finite element models, it is much less sensitive to mesh distortion than other 4-node isoparametric elements and free of various locking problems that arise from irregular mesh geometries. In order to extend these advantages of QACM to nonlinear applications, the total Lagrangian (TL) formulations of element AGQ6-I was established in this paper, which is also the first time that a plane QACM element being applied in the implicit geometrically nonlinear analysis. Numerical examples of geometrically nonlinear analysis show that the presented formulations can prevent loss of accuracy in severely distorted meshes, and therefore, are superior to those of other 4-node isoparametric elements. The efficiency of QACM for developing simple, effective and reliable serendipity plane membrane elements in geometrically nonlinear analysis is demonstrated clearly.     

网格状网络的设计探讨

网格状网络正日益成为核心传送网首选的建网方式。着重介绍了网格状网络的特点和优势，构建网格状网络需考虑的因素及步骤。