一种适用于虚拟机网络的数据包高效传输方法

为了提高数据包在云计算数据中心中基于虚拟机构成网络中的传输性能,提出了一种基于网络编码的高效数据包传输方法.基于网络编码机制,采用对传输过程中丢失数据包高效的编码组合策略,多个虚拟机终端可以在一次多播或广播传输中获取多个从交换机优先传输的数据包,因此,提出的方法可以提高基于虚拟机网络的多播及广播业务的数据包传输延迟,并提高多播及广播业务的网络吞吐量.仿真结果表明提出的方法在典型信道条件下均获得了较好的数据包传输时延及网络吞吐量性能.     

A new method to calculate the pressure drop loss of the regenerator in VM refrigerator

The VM refrigerator, known as heat driven refrigerator, is one kind of closed-cycle regenerative refrigerator. There are some losses in VM refrigerator, but the losses in regenerator are the main loss when the refrigeration temperature is below 100 K. This paper present one method to calculate the pressure drop loss in the regenerator, which is one main part loss in the regenerator. The pressure drop loss in the regenerator will decrease the refrigeration capacity in two aspects. On the one hand, due to the friction pressure drop in the regenerator will be converted into heat that causes reduced the refrigeration capacity. On the other hand, the pressure drop in the regenerator will decrease the pressure ratio in cold end. From a practical standpoint, this calculation method was used for analysis one VM refrigerator proposed by Zhou in 1984. The results showed that the results by using this method are very close to the experimental results in three temperature points.     

Creep properties and damage behaviour of component-like tubes of Vm12-materials

Abstract

The gap in the energy supply between current availability and the rising demand for electricity worldwide has to be closed primarily by using modern steam and gas power stations with an increased degree of efficiency and decreased CO₂ emissions. Target values for reaching a high degree of efficiency of ≥50% demand increase the steam parameters. The modern creep-resistant steels and their weldments have to have both high creep rupture strength and corrosion resistance.

Within the European research programme COST 536, between 2005 and 2009 research and development work in the field of power plant steels had been carried out for conventional applications. The project was focused on the development of appropriate materials, coatings and surface treatments for components in steam power plants with steam inlet temperatures in the turbine of up to 650°C.

In framework COST 536, Siempelkamp Pruef- und Gutachter-Gesellschaft mbH (SPG) performed component-like creep tests at pressurized tubes made of martensitic steel VM12. This steel was developed by Vallourec & Mannesmann Tubes with the aim of reaching both sufficient creep strength and increased oxidation resistance and is already used for boiler application in new power plants in Germany.

In this paper, the experimental results of uniaxial creep tests, component-like creep tests on tubes with inner pressure and axial loading, metallographic examination and damage characterisation are presented. The tubes are equipped with capacitive high temperature strain gauges for on-line monitoring of strain. All testing data will be implemented as inputs for the numeric FE analysis. The effect of multiaxiality and stress redistribution will be discussed.     

Enhancing live virtual machine migration process via optimized resource allocation in next generation mobile edge network: A hybrid evolutionary approach

The evolution of 5th Generation wireless technology introduced Mobile Edge Computing, where edge servers are placed at the edge of the network, and are associated with evolved Node Base Stations (eNBs). This enables mobile users to offload their resource‐intensive tasks to these servers and improve network performance by reducing end‐to‐end delay. However, frequent user mobility leads to frequent re‐planning of network and increases network load. This demands dynamic Virtual Machine (VM) migration in Mobile Edge paradigm for an improved Quality of Service (QoS). For an enhanced VM migration process, an optimal pair of migrating VMs and destination edge servers needs to be chosen. In this paper, we propose an optimized decision‐making policy that chooses such optimal pairs. Several decision parameters such as average wait time, processing delay, migration delay, transmission power, and processing power are modeled. A profit function is developed using these modeled decision parameters that chooses the optimal pairs. This function is maximized using the proposed hybrid evolutionary algorithm, which combines the advantages of PSO and GA. The pairs are chosen in such a manner, that the selection guarantees high network throughput, reduced service delay, and energy consumption which is reflected in the simulation.     

基于MiniGUI的嵌入式Java虚拟机实现

针对现有的运行于QT图形库上的Kaffe虚拟机中存在的诸多问题，通过深入分析Kaffe虚拟机的原理及体系结构，提出了将Kaffe的AWT类库移植到嵌入式图形库MiniGUI上的方案，并在嵌入式Linux上给予了完整的实现。结果表明，采用该方案所实现的系统很好的克服了基于QT的旧系统上存在的各种问题。     

基于VXI的VM6068串行通讯模块设计

虚拟仪器技术和VXI总线是当前测试控制领域的新技术 ,它代表了未来仪器的发展方向。采用图形化编程语言LabView ,完成对计算机硬件测试平台的VM60 68模块串行通信子系统开发设计 ,给出了主要测试程序 ,得到良好实验效果     

Two‐graph analysis of pathological equivalent networks

Recently, abstract current mirror and voltage mirror elements have been proposed for behavioral modeling of active analog blocks. Such artificial elements and the traditionally used nullor element together are called pathological elements in the literature. Pathological elements are very useful in modeling and analysis of active network. Hence, researchers have been motivated to study symbolic analysis methods for networks containing pathological elements. However, so far, only nodal admittance matrix analysis has been formulated. In this work, an alternative two‐graph method is formulated, which has the advantage of providing a compact intermediate form for subsequent symbolic term generation. With a compact two‐graph representation, either a matrix method or a tree enumeration method can be employed. For completeness, the classical two‐graph theory has been extended in this paper to encompass all four types of dependent sources and all pathological elements. Illustrative examples are presented to demonstrate the principle of compact symbolic term generation by the presented two‐graph method. Copyright © 2014 John Wiley & Sons, Ltd.     

硬件虚拟机技术与可靠的文件监控

信息技术迅猛发展的同时给信息安全带来了新的挑战。文件监控技术是保障计算机安全的有效手段。设计并实现了主机文件监控系统,能够对文件操作进行记录与分析,并利用硬件虚拟技术对操作系统关键区域进行了保护。最后,通过实验讨论了这些关键技术的实现机制与应用环境。     

基于本地虚拟化技术的隐藏进程检测

自隐藏恶意代码已成为PC平台下急需解决的安全问题,进程隐藏则是这类恶意代码最常用和最基本的规避检测的自隐藏技术。针对这个问题,提出了一种新的基于本地虚拟化技术的隐藏进程检测技术——Gemini。基于该本地虚拟化技术,Gemini在本地化启动的虚拟机中（Local-Booted Virtual Machine)完整重现了宿主操作系统的运行环境,结合隐式的真实进程列表（TVPL)获取技术,Gemini实现了在虚拟机监视器（VMM)内检测宿主操作系统内隐藏进程的能力。测试结果证明了宿主计算环境重现的有效性与隐藏进程检测的完整性。