通过局部平均法在潜在位置图上实现节点回归,提升预测精度。
Node Regression on Latent Position Random Graphs via Local Averaging
- 用邻域节点值的局部平均作为基础估计方法
- 理论证明其收敛速度等同于Nadaraya-Watson估计器
- 可自适应调整平均区域大小,适用于不同图结构
节点回归任务是在已知其他节点标签值的情况下,预测目标节点的标签值。为理解不同估计器在此任务中的表现,本文在随机图背景下进行理论分析,假设图由潜在位置模型生成:每个节点具有潜在位置,边的存在概率取决于两节点潜在位置间的距离。研究中最简单的估计器是将目标节点所有邻居的标签值取平均。我们证明该方法在潜在空间中趋于Nadaraya-Watson估计器,且收敛速率相同。然而,该方法平均范围固定为邻域,可能过大或过小。为此提出新方法:先估计潜在位置间的真实距离,再将其用于经典Nadaraya-Watson估计器,从而可灵活调整平均区域大小。在某些情况下,即使原始邻域过大或过小,该方法仍能达到标准非参数估计率。
原文摘要 · Abstract (English)
Node regression consists in predicting the value of a graph label at a node, given observations at the other nodes. To gain some insight into the performance of various estimators for this task, we perform a theoretical study in a context where the graph is random. Specifically, we assume that the graph is generated by a Latent Position Model, where each node of the graph has a latent position, and the probability that two nodes are connected depend on the distance between the latent positions of the two nodes. In this context, we begin by studying the simplest possible estimator for graph regression, which consists in averaging the value of the label at all neighboring nodes. We show that in Latent Position Models this estimator tends to a Nadaraya Watson estimator in the latent space, and that its rate of convergence is in fact the same. One issue with this standard estimator is that it averages over a region consisting of all neighbors of a node, and that depending on the graph model this may be too much or too little. An alternative consists in first estimating the true distances between the latent positions, then injecting these estimated distances into a classical Nadaraya Watson estimator. This enables averaging in regions either smaller or larger than the typical graph neighborhood. We show that this method can achieve standard nonparametric rates in certain instances even when the graph neighborhood is too large or too small.
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