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arXiv 2203.01746cs.SI
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SaPHyRa:一种大型网络节点排序的学习理论方法

SaPHyRa: A Learning Theory Approach to Ranking Nodes in Large Networks

Phuc Thai, My T. Thai, Tam Vu, Thang N. Dinh

摘要:

在大规模网络中,基于中心性的节点排序是一个基本的、但又具有挑战性的问题。近似方法可以快速估计节点的中心性,并确定最中心的节点,但大多数剩余节点的排名可能是毫无意义的。例如,已知搜索查询中对不太知名的网站的排名是嘈杂且不稳定的。为此,我们研究了一个新的节点排名问题,其中有两个重要的区别:a)排名质量,而不是中心估计质量,作为主要目标;以及b)仅对感兴趣的节点进行排名,例如,符合搜索条件的网站。我们提出了样本空间分区假设排名,或SaPHyRa,它将节点排名转换为机器学习中的假设排名。这种转换将节点的中心性映射到假设的预期风险,为理论机器学习(ML)工具打开了大门。SaPHyRa的关键是将样本空间划分为精确子空间和近似子空间。精确的子空间包含与感兴趣的节点相关的样本,从而提高估计和排名质量。近似空间可以有效地采样ML为基础的技术提供理论保证的估计误差。最后,我们提出了SaPHyRa_bc,一个说明SaPHyRa对排名节点的介数中心性(BC)。通过结合一种新的双分量采样,2跳样本划分,和改进的Vapnik-Chervonenkis维度的界限,SaPHyRa_bc可以有效地排名BC中的任何节点子集。在近似BC方面,其性能比最先进的方法快200倍,而其与地面真实值的秩相关性提高了数倍。

英文摘要:

Ranking nodes based on their centrality stands a fundamental, yet, challenging problem in large-scale networks. Approximate methods can quickly estimate nodes' centrality and identify the most central nodes, but the ranking for the majority of remaining nodes may be meaningless. For example, ranking for less-known websites in search queries is known to be noisy and unstable. To this end, we investigate a new node ranking problem with two important distinctions: a) ranking quality, rather than the centrality estimation quality, as the primary objective; and b) ranking only nodes of interest, e.g., websites that matched search criteria. We propose Sample space Partitioning Hypothesis Ranking, or SaPHyRa, that transforms node ranking into a hypothesis ranking in machine learning. This transformation maps nodes' centrality to the expected risks of hypotheses, opening doors for theoretical machine learning (ML) tools. The key of SaPHyRa is to partition the sample space into exact and approximate subspaces. The exact subspace contains samples related to the nodes of interest, increasing both estimation and ranking qualities. The approximate space can be efficiently sampled with ML-based techniques to provide theoretical guarantees on the estimation error. Lastly, we present SaPHyRa_bc, an illustration of SaPHyRa on ranking nodes' betweenness centrality (BC). By combining a novel bi-component sampling, a 2-hop sample partitioning, and improved bounds on the Vapnik-Chervonenkis dimension, SaPHyRa_bc can effectively rank any node subset in BC. Its performance is up to 200x faster than state-of-the-art methods in approximating BC, while its rank correlation to the ground truth is improved by multifold.

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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