共查询到15条相似文献，搜索用时 125 毫秒
1.
随着新一代互联网技术的发展,流媒体应用逐渐向IPv6协议迁移,造成了IPv4/IPv6之间流媒体不能互访的问题。简要介绍了基于RTSP协议代理的过渡方法,提出并实现了1种基于SOCKS代理的流媒体代理服务器的设计方案,测试结果表明该代理服务器能够有效的实现IPv4/IPv6之间流媒体应用的互相访问。 相似文献
2.
对开发基于Libpcap、Libnet的IPv6协议分析系统进行深入分析设计,并阐述具体的实现方法,详细分析各函数模块的实现。针对IPv4协议分析作了对比研究。实验结果表明:该系统能很好的实现IPv6下的协议分析。 相似文献
3.
IPv6作为下一代互联网的核心技术,必然会逐步取代IPv4。但在相当长的一段时期内,IPv6会与IPv4共存。利用Java的网络编程设计与实现了1种P2P文件共享系统。该系统能够布署在纯IPv4、IPv6网络上,也可以布署在IPv4/IPv6混合组网的网络上,因此实现了P2P文件共享系统在IPv4和IPv6网络上的无缝连接。 相似文献
4.
域间路由系统作为Internet的核心基础设施,不但是传递网络可达信息的基本机制、自治系统互连的纽带和ISP实现策略控制的主要手段,而且对Internet的安全性起着关键作用。本文对IPv6环境下域间路由系统的各种安全威胁进行了全面的分类,并对可能采取的方法手段进行了详细地分析论述。进而得出结论,针对基于BGP4+协议的IPv6域间路由系统的攻击仍然是下一代网络环境中攻击的有效手段和途径。 相似文献
5.
随着CNGI(中国下一代互联网示范工程)的正式建成,标志着中国IPv6的发展进入到了真正的部署阶段,在这个大背景下,全面部署基于IPv6的下一代校园网已成为未来几年教育信息化建设的核心工作之一。在对中国海洋大学IPv6网络建设思路进行介绍的基础上,着重探讨IPv6网络建设方案设计和实现过程,并提出了未来的应用方向。 相似文献
6.
基于源路由的IPv6网络瓶颈带宽定位和估计 总被引：1，自引：0，他引：1
网络瓶颈带宽是网络性能的重要指标,现有的瓶颈测量工具只能定位和估计端到端路径的瓶颈带宽,无法定位和估计网络各处的瓶颈带宽,不能满足各种网络设计、管理及应用的需求。文中基于IPv6网络的源路由机制,设计能够定位和估计整个IPv6网络瓶颈带宽的算法和测量包序列,提出基于现代最优化原理的动态规划和分支定界算法,实现了测量工具Netneck。部署在1台探测主机的Netneck就可以定位和估计整个IPv6网络的瓶颈,能够满足全网瓶颈测量的需求。通过部署在CNGI-6PlanetLab平台的大量CERNET2 IPv6网络实验,验证了该算法和工具的有效性。 相似文献
7.
随着信息化速度的快速提升,未来网络中快速移动交换和高效宽带传输是必然趋势。目前在快速移动交换领域内研究的热点是移动MPLS技术,而高效宽带传输在目前的整体带宽条件下还很难得到满足,这就需要使用RSVP资源预留技术来保证在现有带宽条件下的高效传输。文中通过利用IPv6自身具有的移动性和QoS保障方面的优点,提出1种基于IPv6的移动MPLS中资源预留的方案,给出在IPv6环境下快速高效移动交换的一种实现方法。 相似文献
8.
今年5月6日,英国女王伊丽莎白二世和法国总统弗朗索瓦·密特朗主持了连接英伦三岛和欧洲大陆的英吉利海峡海底隧道的通车典礼。这条全长31公里、投资100亿英镑、历时6年多建成的隧道,是世界隧道开凿史上的一个里程碑,是科学技术的结晶,是经济发展的标志,对整个欧洲的交通发展具有划时代的意义。英吉利海峡隧道工程从最初提出设想到建造完工经历了漫长的岁月。早在查理大帝时代欧洲就有人提出修建 相似文献
9.
为了研究富水砂层中新意法施工的变形控制,本文以青岛地铁3号线保河区间隧道为研究对象,采用自行设计的模型试验,通过对孔隙水、土压力、核心土变形与地表变形的监测,开展新意法在富水砂层中隧道开挖中的变形机理研究。试验中进行了对新意法施工过程的模拟,以循环进尺4 cm进行开挖。结果表明,在全支护条件下的第1～2循环,新意法对围岩及地表变形有很好的控制作用,但由于巨大的水压力,加固薄弱处可能出现管涌现象;在极限破坏状态试验中,水压的加大及钢拱架、喷层的缺失导致在第6循环开挖时,隧道于小导管注浆加固尾端发生了小规模土体塌落;当水压力达到一定程度时,砂层发生瞬时坍塌。表明新意法适用于富水砂层隧道的施工,在施工过程中,应注重加固效果和旋喷桩间的搭接,且在拱脚部位也应具有一定厚度的加固体;富水条件下砂土性质非常不稳定,砂土从变形较小到大变形几乎是瞬间发生的。 相似文献
10.
以上海复兴东路大型越江盾构隧道为工程背景。通过建立适合工程结构及工程地质特点的弹性地基模型,在充分考虑隧道结构荷载作用特点、地下水的影响及隧道下部土体反力特性的基础上,推导出了隧道纵向位移的解析表达式,并采用基于土体反力系数的迭代解析方法,计算了部分南线隧道各管片纵向位移值,所得结果与实测结果基本吻合。 相似文献
11.
地下气库的围岩稳定性关系到地下气库的安全与使用。影响地下洞室稳定的因素很多,解析法虽然可以得到精确解,但是只能针对圆形洞室。而数值计算方法可以计算各种情况下围岩的应力、变形、塑性分布等情况。利用有限元分析软件分析了洞室形状对围岩稳定性的影响,确定了合理的洞形;讨论了围岩应力应变随深度的变化规律,以及不同的支护类型对围岩变形的影响,确定了经济合理的支护类型。最终为该地质条件下的洞室围岩稳定设计提供了依据。 相似文献
12.
由于海底隧道的特殊性,其防排水技术与一般陆地隧道有着显著区别,本文介绍了厦门翔安海底隧道的防排水方案设计情况,对方案实施效果进行了评估．得出了海底隧道防排水应结合围岩与支护的自防水功能采取以堵为主的原则,并针对海底隧道防排水方案实施中的问题,提出了对初期支护背后注浆是重点,改进注浆材料等建议．从而论述了防排水技术是海底隧道工程建设的核心问题． 相似文献
13.
Chungsik Yoo 《Marine Georesources & Geotechnology》2017,35(3):305-317
This paper presents the results of an investigation into the effect of lining leakage on the structural performance of lining in subsea tunnels. A parametric study on a number of hypothetical subsea tunnels was conducted within the framework of two-dimensional stress–pore pressure coupled finite element analysis with due consideration of tunnel cover depth, depth of water to seabed, and ground type. The results indicate that the lining leakage increases axial thrust as well as bending moment, with more pronounced increases in bending moment. Also shown is that there exists an increasing trend of leakage induced lining forces with an increase in the water depth above the seabed but with no significant influence from the cover depth. It is also shown that the progressive development of leakage induced lining forces can be best fitted with an exponential function which can be used to predict the lining force increase for a given tunnel condition. Practical implications of the findings are discussed. 相似文献
14.
The presence of a fractured zone at a tunnel face can threaten the stability of the tunnel by causing water leakage and degradation of the soil strength. In this case, to stabilize the tunnel face, the pore water pressure is generally reduced and the loss of soil particles is prevented by installing drainpipes. The installation of drainpipes, however, can cause the concentration of flow channels and other ground instability problems. In this paper, a novel pin-holed pipe anchor is proposed to overcome the problems occurring in subsea tunnels. The pin-holed pipe anchor is a pipe-type support member designed to reinforce the ground while simultaneously enabling flow into the tunnel. Here, the design requirements of the pin-holed pipe anchor were examined through material tests, and the structural–hydraulic characteristics of the pin-holed pipe anchor were investigated through a model test. Furthermore, the applicability of the pin-holed pipe anchor to an actual tunnel was evaluated by numerical analysis of actual tunnels. Through selection of an appropriate perforated drainage area and bonded length, the pin-holed pipe anchor contributed to the improvement of the structural and hydraulic stabilities of the tunnel. 相似文献
15.
More and more deep-seated long submarine tunnels are under construction, which greatly promotes the development of tunneling technology. The complex geological conditions and frequent geological disasters have become great challenges during submarine tunnel excavation. Among them, casualties and economic losses caused by water inrush are on the top levels in all kinds of tunnel geological disasters. Escape routes after water inrush from the working face during submarine tunnel excavation are investigated and optimized in the present study. Numerical simulations are performed using the FLUENT software to probe water flow characteristics after inrush. Two common cases of water inrush during double-line submarine tunnel excavation are researched. The variation rules of velocity and pressure in the tunnels after inrush are analyzed and discussed. The optimized escape routes are achieved. Finally, the water movement laws after inrush from the working face under different excavation situations are further discussed by comparing the two case studies. Water inrush of high velocity occurs on one working face of the double-line submarine tunnel, and the research results are as follows: (1) The velocity close to the tunnel side wall is the minimum, while it is the maximum in the middle position. (2) The pressure changes greatly at the intersection area of the cross passage and the tunnels. (3) The velocity and pressure nearby the working face without water inrush are both small. (4) The velocity at the high location of the cross passage is relatively small. 相似文献