非确定性文档生成器的常数延迟枚举
Constant-Delay Enumeration for Nondeterministic Document Spanners
摘要：
我们认为，信息抽取框架被称为文档spectum，并研究了有效地计算从输入文档中提取的结果，其中提取任务被描述为一个顺序变量集自动机（VA）的问题。我们在枚举算法的设置中提出了这个问题，我们可以首先运行预处理阶段，然后必须在任何两个连续结果之间产生一个小延迟的结果。我们的目标是有一个算法，这是在合并复杂性，即易于处理，在输入文档和VA的大小中;同时确保输入文档大小的最佳可能的数据复杂度界限，即，文档大小的恒定延迟。最近在PODS'18上的几项工作提出了这样的算法，但是在文档大小上具有线性延迟，或者在输入VA的大小上具有指数依赖性（通常是不确定的）。特别是，Florenzano等人认为，我们所期望的运行时保证不能满足一般顺序VA。我们反驳这一点，并表明，给定一个非确定性的顺序VA和输入文档，我们可以枚举的映射的VA上的文件与以下界限：预处理是线性的文件大小和多项式的VA的大小，和延迟是独立的文件和多项式的VA的大小。由此产生的算法，从而实现了易处理的组合复杂性和最佳可能的数据复杂度的界限。此外，它是相当容易描述的，特别是对于所谓的扩展VA的限制情况。
英文摘要：
We consider the information extraction framework known as document spanners, and study the problem of efficiently computing the results of the extraction from an input document, where the extraction task is described as a sequential variable-set automaton (VA). We pose this problem in the setting of enumeration algorithms, where we can first run a preprocessing phase and must then produce the results with a small delay between any two consecutive results. Our goal is to have an algorithm which is tractable in combined complexity, i.e., in the sizes of the input document and the VA; while ensuring the best possible data complexity bounds in the input document size, i.e., constant delay in the document size. Several recent works at PODS'18 proposed such algorithms but with linear delay in the document size or with an exponential dependency in size of the (generally nondeterministic) input VA. In particular, Florenzano et al. suggest that our desired runtime guarantees cannot be met for general sequential VAs. We refute this and show that, given a nondeterministic sequential VA and an input document, we can enumerate the mappings of the VA on the document with the following bounds: the preprocessing is linear in the document size and polynomial in the size of the VA, and the delay is independent of the document and polynomial in the size of the VA. The resulting algorithm thus achieves tractability in combined complexity and the best possible data complexity bounds. Moreover, it is rather easy to describe, in particular for the restricted case of so-called extended VAs.
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。
