一种适用于网络视频监控系统的应用层组播方案

分析了视频监控系统中流媒体转发的特点，提出了一种适用于网络视频监控系统的应用层组播方案，给出了该方案的设计思路和组播算法理论，并展望了进一步的研究要点。     

一种基于节点相关度的无线传感器网络分簇算法

提出了一种基于节点相关度的无线传感器网络分簇算法。该算法根据接收信号强度、节点剩余能量和网络连通度选取簇头节点,根据节点相关度确定簇内成员。分析与仿真结果表明,与经典的LEACH算法相比,该算法选出的簇头分布更均匀,并提高了簇内负载平衡程度,延长了网络生存时间。     

A high efficiency single molecule localisation algorithm with sub-pixel resolution based on fluorescence images

We introduce a technique of fast single molecule localisation including image de-noising and Gaussian mask sub-pixel refinement (IDGM) with the characteristics of simplicity, great computational efficiency as well as high accuracy and precision. The image de-noising corrects images suffering from background and shot noise, and the Gaussian mask is used to derive the centres of single molecules with sub-pixel resolution. We quantitatively evaluate the performance of IDGM compared to two-dimensional direct Gaussian fitting (2DDGF) on 1000 simulated images at variable signal-to-noise ratios (SNRs), where the single molecule diffraction spot is simulated as a point spread function distribution. It is shown that IDGM performs better than 2DDGF in terms of accuracy and precision for all tested SNRs. In addition, the execution time is shorted by one order of magnitude, making the IDGM algorithm suitable for localising single molecules especially for on-line or time-critical applications.     

Indoor odour source localisation using robot: Initial location and surge distance matter?

Learning from insects and animals to enable an autonomous robot to detect chemical emissions caused by fire, toxic gas leakage and explosive at their early stages, and localise their sources swiftly can avoid risking human health and even save lives. This paper presents a series of investigations aimed to find answers for two important questions, one is “Are there advantageous locations when releasing a robot for speedier chemical source localisation with no prior knowledge about the environment as well as the possible location of the source?” The other question is similar but focusing on whether a different surge distance makes any noticeable differences. To find the answers, a simulated autonomous robot and an indoor office-like environment which contains an odour/gas source emitting varying chemical concentration levels as well as constantly varied wind speeds and directions, were adopted.     

基于80C51的地铁车站无线火灾报警系统

针对地铁车站火灾报警系统实时性的要求,设计了一种基于单片机技术的地铁车站火灾报警系统,给出了监控系统的结构.选用了80C51单片机作为系统的主控制器和火灾环境数据采集节点的控制器;选用基于nRF24L01的无线通信芯片作为传感器节点与火灾报警节点间的数据通信.给出了车站火灾数据采集节点、火灾报警主节点电路,设计了以二次加权融合的传感器数据处理算法,提高了系统检测与控制精度.运行结果表明,该系统稳定可靠,抗干扰,能耗低,体积小,成本低,为地铁车站火灾报警提供了一种新技术.     

Two-dimensional nonsteady viscous flow simulation on the Navier-Stokes Computer miniNode

The needs of large-scale scientific computation are outpacing the growth in performance of mainframe supercomputers. In particular, problems in fluid mechanics involving complex flow simulations require far more speed and capacity than that provided by current and proposed Class VI supercomputers. To address this concern, the Navier-Stokes Computer (NSC) was developed. The NSC is a parallel-processing machine, comprised of individual Nodes, each comparable in performance to current supercomputers. The global architecture is that of a hypercube, and a 128-Node NSC has been designed. New architectural features, such as a reconfigurable many-function ALU pipeline and a multifunction memory-ALU switch, have provided the capability to efficiently implement a wide range of algorithms. Efficient algorithms typically involve numerically intensive tasks, which often include conditional operations. These operations may be efficiently implemented on the NSC without, in general, sacrificing vector-processing speed. To illustrate the architecture, programming, and several of the capabilities of the NSC, the simulation of two-dimensional, nonsteady viscous flows on a prototype Node, called the miniNode, is presented.     

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气井井筒流动是一降温、降压过程，如果产量过低就可能产生井底积液而影响产能。文章以部1-2井为例，以压力校正后的二项式产能方程作为流入动态方程、气井垂直管流方程作为流出动态方程，绘制了从原始地层压力到废弃地层压力之间的流入动态曲线及不同井口油压的流出动态曲线。对气井排液临界产量影响因素进行了分析，认为生产管尺寸是影响临界流量的最敏感因素，对于低产气井，使用小油管生产是非常有意义的。将气井排液临界产量曲线绘入节点分析图中并相互结合以确定气井在整个开采过程中的合理产量，方法直观、实用。     

Behaviour of CPW and TFMS lines at high temperature for RF applications in sub-45 nm nodes

Coplanar waveguide (CPW) and thin film microstrip (TFMS) lines integrating porous ultra low-k as inter-metal dielectric layers (k = 2.5) and copper as metal, are for the first time experimentally measured up to 110 GHz and under different temperature conditions, up to 200 °C. The extracted attenuation and propagation coefficients of those transmission lines are compared to simulations performed with MAGWEL software, a frequency domain 3-D Maxwell solver. Based on the characterization results some guidelines related to interconnect design are presented for future applications.     

基于SIEMENS L2网络的生产线控制系统优化改造

基于SIEMENS L2网络的生产线控制系统,由于控制节点多,网络交换数据量大,经常出现网络堵塞现象,为此分两步对该系统进行了改造:第一步减少L2网上的节点数量,缩短了网络长度;第二步将L2网划分为两个物理独立、数据相通的网络。改造后减少了每段网络上的数据量,通讯速率提高,解决了网络堵塞的问题。     

The influence of node sequence and extraneous load induced by graphical overviews on hypertext learning

The effects of four hypertext learning environments with a hierarchical graphical overview were studied on the coherence of the node sequence, extraneous load and comprehension. Navigation patterns were influenced by the type of overview provided (i.e., dynamic, static) and whether navigation was restricted (i.e., restricted, non-restricted). It was hypothesised that redundant use of the overview for inducing a high-coherence reading sequence would result in high extraneous load and low comprehension. Coherence was higher in the dynamic than in the static conditions. Coherence was also higher in the restricted than in the non-restricted conditions. Mental effort as a measure of extraneous load was higher at the end than at the beginning of the learning phase, especially in the dynamic restricted and the static non-restricted conditions, although there was no significant interaction. Comprehension was lowest in the dynamic restricted condition and highest in the dynamic non-restricted and static restricted conditions. Low comprehension in the dynamic restricted condition indicates that overviews can become redundant for reading sequence coherence, negatively impacting comprehension. The evidence suggests that severe restriction of navigation paths should be avoided and that continuous use of overviews such as in dynamic overviews may be detrimental to learning.