论文标题
猫头鹰2 QL中的CQE：“最长的蜜月”方法（扩展版）
CQE in OWL 2 QL: A "Longest Honeymoon" Approach (extended version)
论文作者
论文摘要
最近在语义Web本体论的背景下研究了受控查询评估（CQE）。 CQE的目标是隐藏一些查询答案，以防止外部用户推断机密信息。通常，存在多种隐藏答案的多种无与伦比的方法，并且先前的CQE方法事先选择了哪些答案是可见的，哪些是不可见的。相反，在本文中，我们研究了一种动态CQE方法，即，我们建议根据对先前的评估来更改当前查询的答案。我们的目标是一种系统，除了能够保护机密数据之外，还具有最大合作性，这直觉上意味着它对尽可能多的查询肯定地回答；它通过尽可能延迟答案修改来实现这一目标。我们还证明，我们无法通过静态方法在直觉上模拟我们获得的行为，而与查询历史无关。有趣的是，对于通过拒绝表达的OWL 2 QL本体和策略，我们的语义下的查询评估是一阶重写，因此在数据复杂性中是AC0。这为开发实用算法铺平了道路，我们在本文中也初步讨论了这一算法。
Controlled Query Evaluation (CQE) has been recently studied in the context of Semantic Web ontologies. The goal of CQE is concealing some query answers so as to prevent external users from inferring confidential information. In general, there exist multiple, mutually incomparable ways of concealing answers, and previous CQE approaches choose in advance which answers are visible and which are not. In this paper, instead, we study a dynamic CQE method, namely, we propose to alter the answer to the current query based on the evaluation of previous ones. We aim at a system that, besides being able to protect confidential data, is maximally cooperative, which intuitively means that it answers affirmatively to as many queries as possible; it achieves this goal by delaying answer modifications as much as possible. We also show that the behavior we get cannot be intensionally simulated through a static approach, independent of query history. Interestingly, for OWL 2 QL ontologies and policy expressed through denials, query evaluation under our semantics is first-order rewritable, and thus in AC0 in data complexity. This paves the way for the development of practical algorithms, which we also preliminarily discuss in the paper.
