A 5G Virtualized RAN Based on NO Stack

The virtualized radio access network(v RAN) could implement virtualized baseband functions on general-purpose platforms and expand the processing capacity of the radio access network(RAN) significantly.In this paper,a Not Only Stack(NO Stack) based vR AN is proposed to be employed in the fifth generation(5G) mobile communication system.It adopts advanced virtualization technologies to maintain flexible and sustainable.The baseband processing and storage resources should be sliced and orchestrated agilely to support multi radio access technology(multiRAT) .Also it is analyzed and demonstrated by different use cases to validate the benefits.The proposed v RAN reduces signaling overheads and service response time in the bearer establishment procedure.Concluded from the analyses and demonstrations,the NO Stack based v RAN could support multi-RAT convergence and flexible networking effectively.

Availability Importance Measures for Virtualized System with Live Migration

This paper presents component importance analysis for virtualized system with live migration. The component importance analysis is significant to determine the system design of virtualized system from availability and cost points of view. This paper discusses the importance of components with respect to system availability. Specifically, we introduce two different component importance analyses for hybrid model (fault trees and continuous-time Markov chains) and continuous-time Markov chains, and show the analysis for existing probabilistic models for virtualized system. In numerical examples, we illustrate the quantitative component importance analysis for virtualized system with live migration.

Switching Delay Aware Computing Resource Allocation in Virtualized Base Station

In centralized cellular network architecture,the concept of virtualized Base Station(VBS) becomes attracting since it enables all base stations(BSs) to share computing resources in a dynamic manner. This can significantly improve the utilization efficiency of computing resources. In this paper,we study the computing resource allocation strategy for one VBS by considering the non-negligible effect of delay introduced by switches. Specifically,we formulate the VBS's sum computing rate maximization as a set optimization problem. To address this problem,we firstly propose a computing resource schedule algorithm,namely,weight before one-step-greedy(WBOSG),which has linear computation complexity and considerable performance. Then,OSG retreat(OSG-R) algorithm is developed to further improve the system performance at the expense of computational complexity. Simulation results under practical setting are provided to validate the proposed two algorithms.

The Trade-Off Between Performance and Security of Virtualized Trusted Execution Environment on Android

Nowadays,with the significant growth of the mobile market,security issues on the Android Operation System have also become an urgent matter.Trusted execution environment(TEE)technologies are considered an option for satisfying the inviolable property by taking advantage of hardware security.However,for Android,TEE technologies still contain restrictions and limitations.The first issue is that non-original equipment manufacturer developers have limited access to the functionality of hardware-based TEE.Another issue of hardware-based TEE is the cross-platform problem.Since every mobile device supports different TEE vendors,it becomes an obstacle for developers to migrate their trusted applications to other Android devices.A software-based TEE solution is a potential approach that allows developers to customize,package and deliver the product efficiently.Motivated by that idea,this paper introduces a VTEE model,a software-based TEE solution,on Android devices.This research contributes to the analysis of the feasibility of using a virtualized TEE on Android devices by considering two metrics:computing performance and security.The experiment shows that the VTEE model can host other software-based TEE services and deliver various cryptography TEE functions on theAndroid environment.The security evaluation shows that adding the VTEE model to the existing Android does not addmore security issues to the traditional design.Overall,this paper shows applicable solutions to adjust the balance between computing performance and security.

Scalable group management in large-scale virtualized clusters

To save cost, more and more users choose provision resources at the granularity of virtual machines in cluster systems, especially data centres. Maintaining a consistent member view is the foundation of reliable cluster managements, and it also raises several challenge issues for large scale cluster systems deployed with virtual machines （which we call virtualized clusters）. In this paper, we introduce our experience in design and implementation of scalable member view management on large-scale virtual clusters. Our research contributions include three-aspects ： 1 ） we propose a scalable and reliable management infrastructure that combines a peer-to-peer structure and a hierarchy structure to maintain a consistent member view in virtual clusters; 2 ） we present a light-weighted group membership algorithm that can reach the consistent member view within a single round of message exchange; 3 ） we design and implement a scalable membership service that can provide virtual machines and maintain a consistent member view in virtual clusters. Our work is verified on Dawning 5000A, which ranked No. 10 of Top 500 super computers in November, 2008.

Security Challenges of Virtualization Hypervisors in Virtualized Hardware Environment

The concept of virtualization machines is not new, but it is increasing vastly and gaining popularity in the IT world. Hypervisors are also popular for security as a means of isolation. The virtualization of information technology infrastructure creates the enablement of IT resources to be shared and used on several other devices and applications;this increases the growth of business needs. The environment created by virtualization is not restricted to any configuration physically or execution. The resources of a computer are shared logically. Hypervisors help in virtualization of hardware that is a software interact with the physical system, enabling or providing virtualized hardware environment to support multiple running operating system simultaneously utilizing one physical server. This paper explores the benefits, types and security issues of Virtualization Hypervisor in virtualized hardware environment.

A Cloud-Based Virtualized Execution Environment for Mobile Applications

Smartphones and cloud computing technologies have enabled the development of sophisticated mobile applications. Still, many of these applications do not perform well due to limited computation, data storage, network bandwidth, and battery capacity in a mobile phone. While applications can be redesigned with client-server models to benefit from cloud services, users are no longer in full control of the application. This is also a serious concern. We propose an innovative framework for executing mobile applications in a virfualized cloud environment. With encryption and isolation, this environment is controlled by the user and protected against eavesdropping from cloud providers. We have developed efficient schemes for migrating applications and synchronizing data between execution environments. Performance and power issues within a virtualized execution environment are also addressed using power saving and scheduling techniques that enable automatic, seamless application migration.

Virtualized Wireless SDNs:Modelling Delay Through the Use of Stochastic Network Calculus

Software-defined networks （SDN） have attracted much attention recently because of their flexibility in terms of network management. Increasingly, SDN is being introduced into wireless networks to form wireless SDN. One enabling technology for wireless SDN is network virtualization, which logically divides one wireless network element, such as a base station, into multiple slices, and each slice serving as a standalone virtual BS. In this way, one physical mobile wireless network can be partitioned into multiple virtual networks in a software-defined manner. Wireless virtual networks comprising virtual base stations also need to provide QoS to mobile end-user services in the same context as their physical hosting networks. One key QoS parameter is delay. This paper presents a delay model for software-defined wireless virtual networks. Network calculus is used in the modelling. In particular, stochastic network calculus, which describes more realistic models than deterministic network calculus, is used. The model enables theoretical investigation of wireless SDN, which is largely dominated by either algorithms or prototype implementations.

Heuristic Scheduling Algorithms for Allocation of Virtualized Network and Computing Resources

Cloud computing technology facilitates computing-intensive applications by providing virtualized resources which can be dynamically provisioned. However, user’s requests are varied according to different applications’ computation ability needs. These applications can be presented as meta-job of user’s demand. The total processing time of these jobs may need data transmission time over the Internet as well as the completed time of jobs to execute on the virtual machine must be taken into account. In this paper, we presented V-heuristics scheduling algorithm for allocation of virtualized network and computing resources under user’s constraint which applied into a service-oriented resource broker for jobs scheduling. This scheduling algorithm takes into account both data transmission time and computation time that related to virtualized network and virtual machine. The simulation results are compared with three different types of heuristic algorithms under conventional network or virtual network conditions such as MCT, Min-Min and Max-Min. e evaluate these algorithms within a simulated cloud environment via an abilenenetwork topology which is real physical core network topology. These experimental results show that V-heuristic scheduling algorithm achieved significant performance gain for a variety of applications in terms of load balance, Makespan, average resource utilization and total processing time.

Analysis on the Computer-based Virtualized Educational Platform

In this paper,under the premise of analyzing the necessities to carry out computer virtualized education in modem education and based on computer virtualized training's value embodied in education,the ways to realize the educational value of computer virtualized training are elaborated.Computer virtualized training is of great significance to the diversity of education and the modernization development.

Application of virtual reality technology improves the functionality of brain networks in individuals experiencing pain

Medical procedures are inherently invasive and carry the risk of inducing pain to the mind and body.Recently,efforts have been made to alleviate the discomfort associated with invasive medical procedures through the use of virtual reality(VR)technology.VR has been demonstrated to be an effective treatment for pain associated with medical procedures,as well as for chronic pain conditions for which no effective treatment has been established.The precise mechanism by which the diversion from reality facilitated by VR contributes to the diminution of pain and anxiety has yet to be elucidated.However,the provision of positive images through VR-based visual stimulation may enhance the functionality of brain networks.The salience network is diminished,while the default mode network is enhanced.Additionally,the medial prefrontal cortex may establish a stronger connection with the default mode network,which could result in a reduction of pain and anxiety.Further research into the potential of VR technology to alleviate pain could lead to a reduction in the number of individuals who overdose on painkillers and contribute to positive change in the medical field.

Automated Power Control for Virtualized Infrastructures

Power control for virtualized enviromnents has is keeping underlying infrastructure in reasonably low power gained much attention recently. One of the major challenges states and achieving service-level objectives （SLOs） of upper applications as well. Existing solutions, however, cannot effectively tackle this problem for virtualized environments. In this paper, we propose an automated power control solution for such scenarios in hope of making some progress. The major advantage of our solution is being able to precisely control the CPU frequency levels of a physical environment and the CPU power allocations among virtual machines with respect to the SLOs of multiple applications. Based on control theory and online model estimation, our solution can adapt to the variations of application power demands. Additionally, our solution can simultaneously manage the CPU power control for all virtual machines according to their dependencies at either the application-level or the infrastructure-level. The experimental evaluation demonstrates that our solution outperforms three state-of-the-art methods in terms of achieving the application SLOs with low infrastructure power consumption.

Autonomic Performance and Power Control on Virtualized Servers:Survey, Practices, and Trends

Modern datacenter servers hosting popular Internet services face significant and multi-facet challenges in performance and power control. The user-perceived performance is the result of a complex interaction of complex workloads in a very complex underlying system. Highly dynamic and bursty workloads of Internet services fluctuate over multiple time scales, which has a significant impact on processing and power demands of datacenter servers. High-density servers apply virtualization technology for capacity planning and system manageability. Such virtuMized computer systems are increasingly large and complex. This paper surveys representative approaches to autonomic performance and power control on virtualized servers, which control the quality of service provided by virtualized resources, improve the energy efficiency of the underlying system, and reduce the burden of complex system management from human operators. It then presents three designed self-adaptive resource management techniques based on machine learning and control for percentile-based response time assurance, non-intrusive energy-efficient performance isolation, and joint performance and power guarantee on virtualized servers. The techniques were implemented and evaluated in a testbed of virtualized servers hosting benchmark applications. Finally, two research trends are identified and discussed for sustainable cloud computing in green datacenters.

QoS-aware simulation job scheduling algorithm in virtualized cloud environment

Cloud computing is attracting an increasing number of simulation applications running in the virtualized cloud data center.These applications are submitted to the cloud in the form of simulation jobs.Meanwhile,the management and scheduling of simulation jobs are playing an essential role to offer efficient and high productivity computational service.In this paper,we design a management and scheduling service framework for simulation jobs in two-tier virtualization-based private cloud data center,named simulation execution as a service(SimEaaS).It aims at releasing users from complex simulation running settings,while guaranteeing the QoS requirements adaptively.Furthermore,a novel job scheduling algorithm named adaptive deadline-aware job size adjustment(ADaSA)algorithm is designed to realize high job responsiveness under QoS requirement for SimEaaS.ADaSA tries to make full use of the idle fragmentation resources by tuning the number of requested processes of submitted jobs in the queue adaptively,while guaranteeing that jobs’deadline requirements are not violated.Extensive experiments with trace-driven simulation are conducted to evaluate the performance of our ADaSA.The results show that ADaSA outperforms both cloud-based job scheduling algorithm KCEASY and traditional EASY in terms of response time(up to 90%)and bounded slow down(up to 95%),while obtains approximately equivalent deadline-missed rate.ADaSA also outperforms two representative moldable scheduling algorithms in terms of deadline-missed rate(up to 60%).

An efficient and coordinated mapping algorithm in virtualized SDN networks

Software-defined networking(SDN) enables the network virtualization through SDN hypervisors to share the underlying physical SDN network among multiple logically isolated virtual SDN networks(v SDNs),each with its own controller.The v SDN embedding,which refers to mapping a number of v SDNs to the same substrate SDN network,is a key problem in the SDN virtualization environment.However,due to the distinctions of the SDN,such as the logically centralized controller and different virtualization technologies,most of the existing embedding algorithms cannot be applied directly to SDN virtualization.In this paper,we consider controller placement and virtual network embedding as a joint vS DN embedding problem,and formulate it into an integer linear programming with objectives of minimizing the embedding cost and the controller-to-switch delay for each v SDN.Moreover,we propose a novel online vS DN embedding algorithm called CO-v SDNE,which consists of a node mapping stage and a link mapping stage.In the node mapping stage,CO-vS DNE maps the controller and the virtual nodes to the substrate nodes on the basis of the controller-to-switch delay and takes into account the subsequent link mapping at the same time.In the link mapping stage,CO-v SDNE adopts the k-shortest path algorithm to map the virtual links.The evaluation results with simulation and Mininet emulation show that the proposed CO-v SDNE not only significantly increases the long-term revenue to the cost ratio and acceptance ratio while guaranteeing low average and maximum controller-to-switch delay,but also achieves good v SDN performance in terms of end-to-end delay and throughput.

Writeback throttling in a virtualized system with SCM

Storage class memory （SCM） has the potential to revolutionize the memory landscape by its non-volatile and byte-addressable properties. However, there is little published work about exploring its usage for modem virtualized cloud infrastructure. We propose SCM-vWrite, a novel architecture designed around SCM, to ease the performance interference of virtualized storage subsystem. Through a case study on a typical virtualized cloud system, we first describe why cur- rent writeback manners are not suitable for a virtualized en- vironment, then design and implement SCM-vWrite to im- prove this problem. We also use typical benchmarks and re- alistic workloads to evaluate its performance. Compared with the traditional method on a conventional architecture, the ex- perimental result shows that SCM-vWrite can coordinate the writeback flows more effectively among multiple co-located guest operating systems, achieving a better disk I/O perfor- mance without any loss of reliability.

Huge Page Friendly Virtualized Memory Management

With the rapid increase of memory consumption by applications running on cloud data centers,we need more efficient memory management in a virtualized environment.Exploiting huge pages becomes more critical for a virtual machine's performance when it runs large working set size programs.Programs with large working set sizes are more sensitive to memory allocation,which requires us to quickly adjust the virtual machine's memory to accommodate memory phase changes.It would be much more efficient if we could adjust virtual machines'memory at the granularity of huge pages.However,existing virtual machine memory reallocation techniques,such as ballooning,do not support huge pages.In addition,in order to drive effective memory reallocation,we need to predict the actual memory demand of a virtual machine.We find that traditional memory demand estimation methods designed for regular pages cannot be simply ported to a system adopting huge pages.How to adjust the memory of virtual machines timely and effectively according to the periodic change of memory demand is another challenge we face.This paper proposes a dynamic huge page based memory balancing system(HPMBS)for efficient memory management in a virtualized environment.We first rebuild the ballooning mechanism in order to dispatch memory in the granularity of huge pages.We then design and implement a huge page working set size estimation mechanism which can accurately estimate a virtual machine's memory demand in huge pages environments.Combining these two mechanisms,we finally use an algorithm based on dynamic programming to achieve dynamic memory balancing.Experiments show that our system saves memory and improves overall system performance with low overhead.

Energy-aware application performance management in virtualized data centers

Both performance and energy cost are impor- tant concerns for current data center operators. Traditionally, however, IT and mechanical engineers have separately op- timized the cyber and physical aspects of data center operations. This paper considers both of these aspects with the eventual goal of developing performance and power management techniques that operate holistically to control the entire cyber-physical complex of data center installations. Toward this end, we propose a balance of payments model for holis- tic power and performance management. As an example of coordinated cyber-physical system management, the energy- aware cyber-physical system （EaCPS） uses an application controller on the cyber side to guarantee application perfor- mance, and on the physical side, it utilizes electric current- aware capacity management （CACM） to smartly place exe- cutables to reduce the energy consumption of each chassis present in a data center rack. A web application, representa- tive of a multi-tier web site, is used to evaluate the perfor- mance of the controller on the cyber side, the CACM control on the physical side, and the holistic EaCPS methods in a mid-size instrumented data center. Results indicate that coor- dinated EaCPS outperforms separate cyber and physical con- trol modules.

NDFuzz:a non-intrusive coverage-guided fuzzing framework for virtualized network devices

Network function virtualization provides programmable in-network middlewares by leveraging virtualization tech-nologies and commodity hardware and has gained popularity among all mainstream network device manufacturers.Yet it is challenging to apply coverage-guided fuzzing,one of the state-of-the-art vulnerability discovery approaches,to those virtualized network devices,due to inevitable integrity protection adopted by those devices.In this paper,we propose a coverage-guided fuzzing framework NDFuzz for virtualized network devices with a novel integrity protec-tion bypassing method,which is able to distinguish processes of virtualized network devices from hypervisors with a carefully designed non-intrusive page global directory inference technique.We implement NDFuzz atop of two black-box fuzzers and evaluate NDFuzz with three representative network protocols,SNMP,DHCP and NTP,on nine popular virtualized network devices.NDFuzz obtains an average 36%coverage improvement in comparison with its black-box counterparts.NDFuzz discovers 2 O-Day vulnerabilities and 11-Day vulnerability with coverage guidance while the black-box fuzzer can find only one of them.All discovered vulnerabilities are confirmed by corresponding vendors.

基于VR看房及网络大数据的住宅活荷载建模

活荷载取值是建筑结构可靠性设计的基础,样本采集又是荷载建模的关键。针对传统的抽样采集、入户称重的研究方式存在的入户难、称重难、效率低和样本少等问题,提出了基于网络房产中介平台开放的全景虚拟(virtual reality,VR)看房方式及网络大数据研究住宅持久性活荷载的方式。首先,利用VR看房获得房间尺寸、室内物品类型及数量等数据,再通过网络爬虫从互联网大数据资源中获得物品重量,实现非称重方式的活荷载调查。采用该方法调查了9座城市的4676个住宅房间样本(总面积近75000m2),通过数据统计分析与荷载组合得到了住宅活荷载标准值,并与现行规范建议值进行了对比。结果表明,任意时点持久性活荷载标准差显著增大,不同城市活荷载变动时间均值不同且整体呈现下降趋势。VR系统结合网络大数据可以实现高效、便捷的住宅活荷载调查,形成一种全新的活荷载研究方式。