A thermal-aware VM consolidation mechanism with outage avoidance

Efficient energy and temperature management techniques are essential elements for operators of cloud data centers. Dynamic virtual machine (VM) consolidation using live migration techniques presents a great opportunity for cloud service providers to adaptively reduce energy consumption and optimize their resource utilization. In recent studies, power consumption readings of individual physical hosts were chosen as the main monitoring parameters in their allocation policies, whereas very few have considered host temperature, which has shown to have a negative impact on server reliability, as a migration criterion. In this work, a thermal-aware VM consolidation mechanism is proposed for resource allocation optimization and server reliability assurance. We consider the variability in host temperature as a migration criterion to avoid outage incidents via having better VM consolidations. Extensive simulation results obtained from CloudSim show the promising performance of the proposed mechanism in energy saving while reducing the number of server outage incidents due to fluctuations in host temperature.     

基于分片的云虚拟机安全保护技术

在典型的IaaS云中,用户使用云服务需要通过虚拟机实现。最近有研究表明,在大多数常用的加密协议(如SSL/TLS等)中,至关重要的加密密钥,可能被攻击者通过跨虚拟机的旁路攻击截获。针对这种攻击方式,提出了一种云虚拟机密钥保护系统,通过将加密密钥随机分割为多个分片,并将每个分片存储于不同的虚拟机中,能有效保护云中的加密密钥,抵御各类跨虚拟机的旁路攻击。此外,云虚拟机密钥保护系统会周期性地对加密密钥进行重新分割,即便攻击者能够截获局部的加密密钥,也无法进行还原。将云虚拟机密钥保护系统作为一种对应用软件透明的扩展库,运行在亚马逊EC2云的web服务器,取得了较好的成果。     

基于PDM的数字化产品虚拟制造系统研究

分析了PDM(Product Data Management,PDM)技术与虚拟制造技术(Virtual Manufacture,VM)的特点及重要性,将产品数据管理技术与虚拟制造技术有机地集成,为新产品开发提供一套更加有效的工具.随着科学技术的发展,数字化产品设计成了产品设计的主流.基于数字化设计制造的思想,将所有产品数据与虚拟制造技术相结合,搭建了PDMVMS(Virtual Manuflacture Svstem based on Product Data Management,PDMVMS)平台,研究了其主要的建模技术与关键问题.     

谈谈IXIA虚拟化测试解决方案如何能帮助“化云为雨”

探讨了云计算在世界以及中国发展的趋势,介绍了在企业里部署云计算所面临的挑战。重点讲述了IXIA作为在IP测试行业有着丰富经验的公司如何利用自己的解决方案通过测试来帮助推动云在企业的落地应用。     

Dynamic memory paravirtualization transparent to guest OS

This paper introduces dynamic paravirtualization, which imitates paravirtualization and aims at reducing VM exits of full virtualization with hardware support. In dynamic paravirtualization, VMM (virtual machine monitor) dynamically monitors and replaces the hot instructions, which cause most VM exits. It is transparent to the guest OS such that the legacy OSes can benefit from this optimization. Our study focuses on reducing the overhead of memory virtualization—dynamic memory paravirtualization (DMP). We ...     

Testing butt joints in pipes made of VM12-SHC martensitic steel

VM12-SHC steel is the newest grade of 12% Cr steel developed by the V&M company. At the present moment, there are works being conducted in order to make use of this steel in steam superheaters. It is also planned to implement VM12-SHC steel to the fabrication of water-walls for prototype boilers operated at very high temperature and pressure parameters. In this article, test materials and welding consumbables are characterized and the process of preparation of pipes to be welded is discussed. The results of metallographic examination and mechanical testing of the test joints are presented.     

电视中心系统测试实践

结合本台硬盘播控系统实际,阐述了模拟向数字过渡时期电视中心系统验收测试的方法,并对测试中的几点体会进行了介绍,最后还阐述了深入使用VM700T的一些方法。     

虚拟机迁移系统网络连接重定向技术*

针对虚拟机（virtual machine,VM）在不同子网间进行在线迁移时,因网络接入点发生改变而无法继续通信的问题,设计和实现了基于代理移动IP（proxy mobile IP,PMIP）的网络连接重定向系统。当VM迁移到外部子网时,将其看做移动节点,不改变IP地址,通过外部网络和家乡网络之间的双向隧道传输所有来自和发往该VM的网络数据。此方案中跨子网的在线迁移行为对VM以及与VM通信的节点透明。实验证明了该系统可以保证VM较快的网络切换速度和较好的网络通信性能。     

温度对VM110SS套管钢在酸性环境中腐蚀行为的影响

模拟川东某气田气井封隔器失效后套管面临的腐蚀环境,利用自制高温高压釜进行VM110SS套管钢在总压18MPa、CO2分压0.54MPa、H2S分压0.41MPa、温度30~150℃条件下的腐蚀实验,得出了该气井工况下温度对VM110SS套管钢腐蚀速率的影响。采用扫描电镜和电子能谱分析方法对试样表面腐蚀产物形貌及成分进行分析。结果表明,VM110SS钢的平均腐蚀速率随温度的升高呈现先增大后减小的规律,气液相腐蚀速率最大值出现在90℃。在90℃气相中腐蚀速率为0.838mm/a、液相中腐蚀速率为1.130mm/a,发生极严重腐蚀。所有实验温度条件下,试样均发生均匀腐蚀,且腐蚀产物以硫铁化合物为主。本实验为酸性气田在不同井深及温度条件下套管的腐蚀状况评估提供了参考。     

虚拟制造中的产品建模技术研究——基于产品定义单元和元建模的产品模型

虚拟制造要求产品模型在多学科无缝集成仿真中能够保持信息的一致性和可重用性 ,传统的产品模型难于满足这一需求。基于虚拟制造对产品建模的要求 ,本文采用特征、零件和装配三个层次的产品定义单元 (PDU)构造产品设计模型 ,基于SUMM元建模技术实现模型间的互操作。虚拟制造各种应用模型可以由此设计模型衍生而来 ,较好地解决了现有产品模型语义信息缺乏的问题 ,并具有良好的一致性、可扩充性、可重用性。