城域以太网技术及其应用

文章分析了城域以太网的核心技术——城域以太网的应用技术和安全技术，并以城域以太网论坛内容为基础，从城域以太网的架构、服务、网络保护和QoS、城域以太网的管理四个方面简要分析了城域以太网技术。最后，介绍了城域以太网技术的应用，即城域以太网提供业务的能力。     

一种基于似三棱柱的三维地学空间建模及应用

三维现象随着研究领域的不同 ,其描述空间实体的方法存在较大差异 ,一种数据模型很难适合所有的应用领域 ,应根据研究领域空间实体分布特征 ,设计出专用的三维空间数据模型。本文对三维GIS及地学领域的空间构模进行了研究 ,提出了一种三维地学空间构模方法———似三棱柱(STP)法。为该构模方法设计了数据结构 ,分析了其空间拓扑关系的建立 ,并在地质三维可视化实例中 ,用似三棱柱法构建三维地质模型。     

Pre-treatment and bioconversion of wastewater sludge to value-added products—Fate of endocrine disrupting compounds

Development of processes for the production of value added products (VAPs), such as biopesticides, microbial inoculants or industrial enzymes through biotransformation of raw or pre-treated wastewater sludge (WWS) has undergone a substantial progress over the last decade. WWS based VAPs are low cost biological alternatives that can compete with chemicals or other cost intensive biological products in the current markets. However, when WWS is used as a raw material for VAPs production, questions still remains on the persistence of organic pollutants within the biotransformed WWS, especially, endocrine disrupting compounds (EDCs) and the production of their toxic intermediates. WWS pre-treatment prior to biotransformation as well as the microbial strains used for biotransformation can possibly remove these organic pollutants. The literature findings concerning the impact of WWS pre-treatment and value added products on EDCs removal are reviewed in this paper. The microbial potential to degrade or detoxify EDCs and toxic intermediates concomitant with value-addition is also discussed. The concept of obtaining EDCs free-WWS based VAPs and simultaneously achieving the objective of pollution control is presented.     

Shear-thickening polishing method

A shear-thickening polishing (STP) method utilizing the shear thickening mechanism of non-Newtonian power-law fluid based slurry is proposed for curved surface polishing. The STP principle and micro-material removal action are analyzed. The high-performance STP slurry with the shear-thickening rheological behaviors has been prepared. To achieve the material removal mechanism of STP process, based on the Preston formula, fluid dynamics and shear thickening mechanism, the material removal rate (MRR) model is established and the difference of MRR between theoretical and experimental results is 6.12%. The experimental and theoretical tests of STP process are conducted to investigate the influences of polishing velocity, abrasive concentration and grain size on MRR and surface roughness. Compared with Newtonian fluid slurry, STP slurry can achieve much higher MRR and better surface quality due to shear-thickening effect. MRR of Cr12Mo1V1 (die steel) is up to 13.69 μm/h, and surface roughness is reduced from R_a 105.95 nm to R_a 5.1 nm within 0.5 h of processing. This indicates that STP is a promising processing method for precision finishing or polishing.     

虚拟化平台下二层网络问题研究

随着虚拟化技术的引入,在单台服务器上虚拟出多个VM,无可避免的会造成网络层次增加,并由此引发出路由环路,广播风暴,单点故障,网络延迟,布线杂乱等各种问题。本文根据虚拟化平台建设过程中的一些经验,总结了虚拟化平台下网络架构需要注意的事项,并结合业界最新的技术趋势,探索虚拟化平台下网络的构想。     

5G SA核心网信令组网方式分析

随着信息通信技术的不断发展,移动通信网络逐步向5G演进。5G SA网络基于服务化接口的新的网络架构,各功能实体间采用基于HTTP2.0协议的信令消息,信令网络如何组网成为5G核心网规划和建设的关键。本文通过分析5G信令的特点,提出信令组网的可行方案,为5G信令网组网提供建议和借鉴。     

STP协议实验测试与仿真测试的比较和研究

为确保计算机网络在网络故障发生时具有生存及恢复能力,需要选择并且测试相关处理故障的正确协议.这些测试如果采用现实的网络设备以及环境,所得出的结果无疑是很可靠的.但受设备和时间所限,这样的测试并不总是可行的.因此本文用仿真环境来模拟实验环境进行测试,然而仿真环境也不是总能模拟真正的网络行为.本文分别采用两种测试方法对STP协议和RSTP协议中的收敛时间进行测试比较,测试从简单的拓扑开始,并最终在仿真环境中实现在实验环境中很难实现的大型拓扑的测试.     

七号信令测试仪呼损分析功能的实现

本文介绍了七号信令测试仪的原理,并对其中的呼损分析功能做了详细的阐述.     

工业以太网冗余技术分析

为了满足工业以太网对网络的可靠性要求，减少因网络故障造成的损失，网络冗余容错技术的提出增加了网络的可靠性和稳定性。文中介绍了网络冗余技术国内外研究的总体情况，讨论了多种网络冗余解决方案，包括生成树协议、快速生成树协议、环网冗余协议和分布式冗余网络协议，以及其他的网络冗余技术，着重讨论了分布式冗余网络协议，’最后对多种网络冗余解决方案进行了比较，特别指出了它们的局限性。