共查询到14条相似文献,搜索用时 156 毫秒
1.
2.
如何在最短的时间内生成长度最短的对称循环请求集,是当前分布式计算乃至云计算必须解决的问题。提出了一种基于有限递归的最短长度对称循环请求集生成算法。该算法通过减少每一个递归层次的递归次数,在不增加请求集长度的情况下,能够有效地减少请求集生成过程中节点尝试的次数,从而有效地降低算法的时间复杂度,具有较高的实用价值。 相似文献
3.
4.
5.
6.
7.
8.
在分布式系统中,各节点必须互斥地访问临界区.节点的请求集的长度决定了系统的效率、性能.虽然最优请求集的节点数最少(大约n),但已有的解决方案该类问题算法类似于穷举法,随着节点的增加,该方法变得不可计算.提出了一种快速的请求集生成算法,该算法以循环差集请求集生成算法的理论和贪心算法的基本思想为基础,在每次迭代的过程中,选出一个当前条件下最优的节点加入请求集.与其他的方法相比较,该方法能对任意给定的整数快速、有效地生成对称的请求集.本算法时间复杂度为O(n2),生成的请求集长度为n~2n. 相似文献
9.
程序设计中没有用到循环或递归算法,很难解决一些实际问题。本文以斐波那契(Fibonacci)数列为例对递归与循环算法的时间复杂度作了比较、分析。 相似文献
10.
11.
Yuh-Jzer Joung 《Parallel and Distributed Systems, IEEE Transactions on》2003,14(5):463-476
We propose a quorum system, which we referred to as the surficial quorum system, for group mutual exclusion. The surficial quorum system is geometrically evident and is easy to construct. It also has a nice structure based on which a truly distributed algorithm for group mutual exclusion can be obtained and processed loads can be minimized. When used with Maekawa's algorithm, the surficial quorum system allows up to /spl radic/2n/m(m-l) processes to access a resource simultaneously, where n is the total number of processes and m is the total number of groups. We also present two modifications of Maekawa's algorithm so that the number of processes that can access a resource at a time is not limited to the structure of the underlying quorum system, but to the number that the problem definition allows. 相似文献
12.
网络资源的共享与保护是移动自组网需要解决的关键问题之一。运用Voronoi图模型和quorum系统的思想,提出了一种移动自组网的动态路径quorum系统,设计了动态路径quorum的生成算法。基于移动自组网的动态路径quorum系统,提出了基于quorum系统的移动自组网的分布式访问控制机制,详细描述了节点的身份认证、网络资源的访问控制和权限管理协议。与传统的基于单个节点自身的访问控制机制相比,该访问控制机制具有较强的抗攻击能力和较高的可靠性,能够有效地提高移动自组网的资源共享与保护水平。 相似文献
13.
Cheung S.Y. Ahamad M. Ammar M.H. 《Knowledge and Data Engineering, IEEE Transactions on》1989,1(3):387-397
In the weighted voting protocol which is used to maintain the consistency of replicated data, the availability of the data to ready and write operations not only depends on the availability of the nodes storing the data but also on the vote and quorum assignments used. The authors consider the problem of determining the vote and quorum assignments that yield the best performance in a distributed system where node availabilities can be different and the mix of the read and write operations is arbitrary. The optimal vote and quorum assignments depend not only on the system parameters, such as node availability and operation mix, but also on the performance measure. The authors present an enumeration algorithm that can be used to find the vote and quorum assignments that need to be considered for achieving optimal performance. When the performance measure is data availability, an analytical method is derived to evaluate it for any vote and quorum assignment. This method and the enumeration algorithm are used to find the optimal vote and quorum assignment for several systems. The enumeration algorithm can also be used to obtain the optimal performance when other measures are considered 相似文献
14.
在大规模完全分布式系统的互斥问题上,快速生成请求集是必要的。在基于松弛差集的相关原理上,引入了二次松弛差集的概念。经分析相关概念及定理,将原本“求差”的过程变为“求和”的过程;进而利用 “求和”步骤间的递推关系,大大减少了求和步骤,使整个算法的时间复杂度控制在O(n)。与时间复杂度同为O(n^2)的其他经典算法相比,生成的请求集长度仍保持在2n^(1/2)的数量级。 相似文献