云计算安全：概念、现状与关键技术

随着云计算的广泛应用,云计算安全问题逐渐凸显出来。文章首先阐述了云计算安全相关概念,并对云计算的安全问题和云计算安全特征进行分析,然后对云计算安全的现状和典型的云计算安全体系架构进行了介绍,并对云计算安全的关键技术进行分析,最后给出了结论。     

云计算安全需求分析研究

云计算是当下发展迅速的信息技术之一。由于其外包式的服务方式,云计算中的安全问题受到人们格外关注。只有妥善地保障云计算的安全,才不会掣肘云计算的发展和推广。鉴于云计算的复杂性和多面性,文章着眼云计算有别于传统技术的新特点、新趋势,首先提出了考量云计算安全需求的多维视角,随后围绕云计算具体实施过程中的若干关键技术,对云计算中的安全需求进行了细致全面的分析和阐释。     

基于SaaS的矿震远程预警系统关键技术初探

现有的矿震预警系统都是以独立形式运行于各矿区,相互之间没有关联,重复投资严重,且矿震数据海量繁杂,仅依靠现场分析无法满足实时预警需求。文章基于感知矿山物联网示范工程(夹河矿),对采用云计算SaaS模式构建的矿震远程预警系统关键技术进行了相关研究:首先给出了系统整体框架,然后重点探讨了该系统所涉及的三个关键技术,包括基于SaaS的矿震预警专家分析软件架构、多源SaaS数据库构建技术以及基于MapReduce的并发数据过滤接收技术。现场应用表明,所构建的系统已基本具备全国统一远程矿震预警系统的架构,能满足多矿区远程矿震预警的基本要求。     

基于云环境的信息系统风险评估模型应用研究

针对云计算环境下网络信息系统会面临更多安全风险问题,总结出8种威胁安全准则,并对应得到影响因素;结合云计算技术具有协作性、虚拟性等特点,采用层次分析法并引入相关系数对多决策目标进行分析,提出一种基于云环境下的信息安全风险评估模型;最后运用该模型建模得出云计算环境下的信息系统安全风险评估思路;实验结果表明文章提出的风险评估模型具有一定的实际应用价值。     

基于云自适应遗传算法的NoC路径分配研究

路径分配是NoC设计流程中的两个关键步骤之一;路径分配的结果对NoC系统的性能尤其是通讯延时有着很重要的影响;多约束条件下的NoC路径分配问题是NP完全问题,要求出其最优解比较困难,目前常用的方法是利用启发式算法求得其较优解;文中提出一种基于云自适应遗传算法的NoC路径分配解决方案,该算法利用云模型对传统遗传算法加以改进,采取新的方法自动调整遗传算法过程中的交叉概率pc和变异概率pm,将适应度与云模型的3个参数Ex、En、He相互结合,从而达到优化遗传算法的目的;将此算法应用于2D-Mesh拓扑结构的NoC中,以平衡链路负载和联合优化为实验目标,以优化静态通讯分配结果;实验证明,文章所采取的算法在平衡链路负载和联合优化方面均取得了良好的效果。     

Run-time generation of partial FPGA configurations

This paper presents and evaluates a method of generating partial bitstreams at run-time for dynamic reconfiguration of sections of an FPGA. The method is intended for use in adaptive embedded systems that employ run-time reconfiguration to achieve high flexibility and performance. The proposed approach combines partial bitstreams of coarse-grained components to produce a new partial bitstream implementing a given circuit netlist. Topological sorting of the netlist is used to determine the initial positions of individual components, whose placement is then improved by simulated annealing. Connection routing is done by a breadth-first search of the reconfigurable area based on a simplified resource model of the reconfigurable fabric. The desired partial bitstream is constructed by merging together the default bitstream of the reconfigurable area, the relocated partial bitstreams of the components, and the configurations of the switch matrices used for routing. The approach is embodied in a code library that applications can use to create new bitstreams at run-time. For the members of a set of 29 benchmarks (both synthetic and application-derived) having between five and 41 components, the complete process of bitstream generation takes between 8 s and 35 s when running on an embedded PowerPC 405 microprocessor clocked at 300 MHz.     

A parallel micro evolutionary algorithm for heterogeneous computing and grid scheduling

This work presents a novel parallel micro evolutionary algorithm for scheduling tasks in distributed heterogeneous computing and grid environments. The scheduling problem in heterogeneous environments is NP-hard, so a significant effort has been made in order to develop an efficient method to provide good schedules in reduced execution times. The parallel micro evolutionary algorithm is implemented using MALLBA, a general-purpose library for combinatorial optimization. Efficient numerical results are reported in the experimental analysis performed on both well-known problem instances and large instances that model medium-sized grid environments. The comparative study of traditional methods and evolutionary algorithms shows that the parallel micro evolutionary algorithm achieves a high problem solving efficacy, outperforming previous results already reported in the related literature, and also showing a good scalability behavior when facing high dimension problem instances.     

基于五层十五级遥感数据结构的并行算法研究

针对当前环境与监测预报小卫星宽覆盖和海量数据显示与处理不足的现状,设计五层十五级遥感数据组织结构,并依据此结构设计一种新的并行计算算法,得到并行计算的最大近优估算值,优化环境与监测预报小卫星海量数据的遥感产品生产能力,提高环境监测预报效率。     

基于并行遗传算法的配送路线求解

遗传算法(Genetic Algorithm)是一类借鉴生物界的进化规律演化而来的随机化搜索方法,已经成功运用在很多大规模的组合优化问题中。利用如今流行的并行计算机系统,对遗传算法进行并行化,可解决标准遗传算法的速度瓶颈问题。本文在MPI并行环境下,用C++语言实现了粗粒度模型的并行遗传算法。结合并行遗传算法的特点,提出了解决物流配送路线优化的策略以及给出相应的算法过程,并进行了有效验证。通过研究结果表明,与传统遗传算法相比,并行遗传算法提高了运算速度,降低了平均开销时间并且最小总路径值更理想。