arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1901.00342cs.DC
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良连通图中的Leader选举

Leader Election in Well-Connected Graphs

Seth Gilbert, Peter Robinson, Suman Sourav

摘要:

在本文中,我们期待在同步分布式网络中的随机领导选举的问题,特别关注的消息的复杂性。我们提供了一个算法,解决了隐式版本的领导者选举(其中非领导者节点不需要知道领导者的身份)在任何一般网络与$O(\sqrt{n} \log^{7/2} n \cdot t_{mix})$消息和$O(t_{mix}\log^2 n)$时间,其中$n$是节点的数量和$t_{mix}$是指网络图$G$中的随机游走的混合时间。对于几类连接良好的网络(具有大电导或小混合时间,例如扩展器,超立方体等),上述结果意味着非常有效的(次线性运行时间和消息)领导者选举算法。相应地,我们表明,任何实质性的改进是不可能的,我们的算法,提出了一个几乎匹配的随机领导人选举的下限。我们表明,$Ω(\sqrt{n}/ϕ^{3/4})$消息是必要的任何领导者选举算法,成功的概率至少$1-o(1)$,其中$ϕ$是指一个图的电导。据我们所知,这是第一个工作,表现出的时间和消息的复杂性之间的依赖关系,以解决领导选举和连接的图形$G$,这往往是其特征在于由图形的电导$ϕ$。除了在[Kutten等人,J.ACM 2015](其中$m$表示图的边数),这项工作还提供了一般网络中领导选举的第一个非平凡下界之一。

英文摘要:

In this paper, we look at the problem of randomized leader election in synchronous distributed networks with a special focus on the message complexity. We provide an algorithm that solves the implicit version of leader election (where non-leader nodes need not be aware of the identity of the leader) in any general network with $O(\sqrt{n} \log^{7/2} n \cdot t_{mix})$ messages and in $O(t_{mix}\log^2 n)$ time, where $n$ is the number of nodes and $t_{mix}$ refers to the mixing time of a random walk in the network graph $G$. For several classes of well-connected networks (that have a large conductance or alternatively small mixing times e.g. expanders, hypercubes, etc), the above result implies extremely efficient (sublinear running time and messages) leader election algorithms. Correspondingly, we show that any substantial improvement is not possible over our algorithm, by presenting an almost matching lower bound for randomized leader election. We show that $Ω(\sqrt{n}/ϕ^{3/4})$ messages are needed for any leader election algorithm that succeeds with probability at least $1-o(1)$, where $ϕ$ refers to the conductance of a graph. To the best of our knowledge, this is the first work that shows a dependence between the time and message complexity to solve leader election and the connectivity of the graph $G$, which is often characterized by the graph's conductance $ϕ$. Apart from the $Ω(m)$ bound in [Kutten et al., J.ACM 2015] (where $m$ denotes the number of edges of the graph), this work also provides one of the first non-trivial lower bounds for leader election in general networks.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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