Emerging MXene-Based Memristors for In-Memory,Neuromorphic Computing,and Logic Operation

Confronted by the difficulties of the von Neumann bottleneck and memory wall, traditional computing systems are gradually inadequate for satisfying the demands of future data-intensive computing applications. Recently, memristors have emerged as promising candidates for advanced in-memory and neuromorphic computing, which pave one way for breaking through the dilemma of current computing architecture. Till now, varieties of functional materials have been developed for constructing high-performance memristors. Herein, the review focuses on the emerging 2D MXene materials-based memristors. First, the mainstream synthetic strategies and characterization methods of MXenes are introduced. Second, the different types of MXene-based memristive materials and their widely adopted switching mechanisms are overviewed. Third, the recent progress of MXene-based memristors for data storage, artificial synapses, neuromorphic computing, and logic circuits is comprehensively summarized. Finally, the challenges, development trends, and perspectives are discussed, aiming to provide guidelines for the preparation of novel MXene-based memristors and more engaging information technology applications.     

使能未来工厂的5G能力综述

5G系统将移动通信服务从移动电话、移动宽带和大规模机器通信扩展到新的应用领域，即所谓对通信服务有特殊要求的垂直领域。对使能未来工厂的5G能力进行了全面的分析总结，包括弹性网络架构、灵活频谱、超可靠低时延通信、时间敏感网络、安全和定位，而弹性网络架构又包括对网络切片、非公共网络、5G局域网和边缘计算的支持。希望从广度到深度，对相关的理论及技术应用做透彻、全面的梳理，对其挑战做清晰的总结，从而为相关研究和工程技术人员提供借鉴。     

雾网络中基于统计分布的内容缓存与交付方案

作为5G中的一种重要模型,雾无线接入网络(Fog Radio Access Network, F-RAN)通过设备到设备通信和无线中继等技术获得了显著的性能增益,而边缘设备中合适的缓存则可以让内容缓存用户(Caching Users, CUs)向内容请求用户(Requesting Users, RUs)直接发送缓存内容,有效减小前传链路的负担和下载延迟。考虑一个F-RAN模型下用户发出请求并获得交付的场景,将每个CU的内容请求队列建模为独立的M/D/1模型,分析导出CUs缓存命中率和平均下载延迟关于内容缓存与交付方案的表达式,证明CUs缓存命中率与内容统计分布之间的联系有助于实现前者的近似最优解。针对在一段时间内的期望视角下建立的优化问题,提出了基于统计分布的算法并注意了执行时的交付控制。仿真结果表明,相较于现有缓存策略,优化内容整体统计分布的方案能够最大化CUs缓存命中率,同时减小平均下载延迟。     

云计算中的服务可用性保障机制简

提出了一种基于滑动窗口的资源预留SWRR(sliding window based resource reservation)算法,它将预留资源在整个资源池中所占的比例称为窗口。窗口的“滑动”包含2层含义：1）窗口大小动态变化;2）窗口中的资源动态刷新。SWRR已被应用于一个大型的云计算应用平台。实验数据表明,SWRR通过合理资源预留,在兼顾所有任务调度的基础上,可为特定用户提供有效的服务可用性保障。     

A novel clustering and optimal resource scheduling in vehicular cloud networks using MKMA and the CM-CSO algorithm

Various opportunities aimed at the employment of delay-sensitive applications in the vehicular environment are presented by the vehicular cloud (VC). Contrary to diverse wireless networks, VC networks possess exceptional features among others, namely, shorter transmission time along with a higher dynamic topology. Although integration with the cloud offers higher storage along with computation capabilities, it as well entails restricted resource availability. The restrictions on the number of resources serve as a challenge in servicing the applications with their necessary quality of service (QoS) guarantees as the number of service requests for applications keeps on augmenting with diverse circumstances. Thus, the need for an effective scheduling methodology arises to decide the sequence of servicing application requests and successful utilization of a broadcast medium, along with data transmission. To do efficient resource scheduling on VC networks, an optimization algorithm, namely, the crossover and mutation (CM)-centered chicken swarm optimization (CSO) is proposed and implemented with the help of a publicly available dataset. Initially, the VC infrastructure is initialized and some vehicle information is extracted as features. Next, the Brownian motion-centered bacteria foraging optimization (BM-BFO) algorithm chooses the essential features. Centered on the chosen features, the vehicles are clustered using the modified K-means algorithm. Next, as for the cloud server's virtual machines (VMs), the resource information is extracted. Lastly, the CM-CSO algorithm carries out the optimal scheduling in the VC by means of the clustered features of vehicles and features of the VM. The proposed techniques' findings are scrutinized and analogized to the other prevailing methodologies to confirm that the proposed work performs effectively and gives optimal resource allocation (RA) to the VC.     

PSMECS: A provably secure ID-based communication in mobile edge computing

Human-centered systems play an important role in the modern world, for example, driverless car, autonomous and smart vehicles, drones, and robotics. The internet of things environment demands a faster real-time response depending on the applications processed in a particular duration. Mobile edge computing (MEC) allows a user to get a real-time response as compared with cloud computing (CC), although ensuring a number of security attributes in MEC environment remains challenging. In this article, a protocol is designed to achieve mutual authentication, anonymous communication, and security against traceability, as these are very crucial factors to ensure the security of data and user's privacy. Moreover, the proposed scheme ensures mutual authentication between a mobile user and an edge server along with the user's anonymity and untraceability. The proof of security and evaluation of performance of the scheme validates that it ensures security attributes and improves efficiency in terms of communication and computation overheads.     

一种面向云服务提供商的资源分配机制

针对用户、服务提供商(SP)和基础设施提供商三者之间的市场行为所带来的收益问题,该文面向服务提供商提出了一种两阶段多虚拟机资源分配机制。首先,建立能力规划模型并引入粒子群算法,决策出服务提供商收益最大化的资源购买方案。然后,提出一种优化用户满意度的服务提供策略,优化了服务提供商的长期收益。最后仿真实验结果表明,该方法有效提高了服务提供商的收益,并取得了较好的用户满意度。     

基于随机网络演算的车联网边缘计算多跳任务卸载性能分析

车联网(IoV)边缘计算通过在网络边缘部署计算资源,可为车载用户提供低时延服务。该文通过随机网络演算(SNC)矩母函数(MGF)法分析车联网移动边缘计算的时延和数据积压性能。首先,分别对车辆高优先级和低优先级业务到达过程、单跳毫米波通信服务过程和边缘计算服务过程进行数学建模;其次,由服务级联定理获得不同优先级业务在多跳网络中的服务过程及其矩母函数表达式;接着,推导了车辆边缘网络不同优先级业务毫米波多跳通信任务卸载的时延和数据积压概率边界闭式解;最后通过蒙特卡罗仿真验证闭式解的准确性。     

一种面向云平台的虚拟机内存SLA审计机制

针对云计算的服务模式屏蔽了云租户的物理硬件视图,不可信的云服务提供商(cloud service provider,CSP)可能利用廉价的硬盘资源通过虚拟化技术,违背服务等级协议约定(service level agreement,SLA)按物理内存定价标准为云租户提供服务这一问题,为了审计CSP提供内存服务的SLA合约性,提出了由Xen层到物理硬件层的内存轻量级测量的SLA合约性审计方案.同时引入可信启动机制和HyperSentry用于保证审计系统的可信启动和完整性运行,提出了带云租户签名机制的Diffie-Hellman密钥交换协议支持策略安全和可信告警.实验结果表明,在虚拟机运行环境下该方法能高效地进行内存SLA合约性审计,同时具有较高的云租户自定义策略扩展性和较低的性能开销.     

基于云计算环境下的分布存储技术

云计算是一种新型的计算模式,它在商业计算领域与科学计算领域均占据着重要的成分,由于其可以将大量的数据存储于数据中心,并可以提供稳定、安全、可靠的数据存储服务特点,并可以在任意时刻供上层的应用,因此云计算得到了各界的重视。但由于云计算的核心部分由许多节点组成,这就增加了云计算的成本费用,对其的发展起到一定程度的限制作用。本文主要针对如何提高云计算的容错性以及可扩展性,最大程度的降低其成本费用等,对云计算环境下的分布存储技术做些简要的分析。