ITR/IIS: Querying Heterogeneous and Uncertain Information

有许多不同的来源，可以从其中获得相关的信息，以完成手头的情报任务，如分析基地组织的行动计划。 这些信息的准确性往往是不完美的。 从每个来源获得的信息在结构和范围上也常常不同。XML已经成为当今信息交换的标准。 它的灵活性允许在一个统一的框架中表示来自异构源的信息。这个项目的目标是管理用XML表示的不确定（概率）数据。 虽然以前已经有开发概率关系系统的努力，但对于不容易服从关系表示的松散结构数据，表示和查询不确定信息的需求要大得多。XML数据提出了几个建模挑战，这些挑战是本项目的重点：由于数据具有（包含层次结构）结构，概率不能独立分配;由于XML元素出现在多个粒度上，概率可以在多个级别上分配;由于子元素丢失和重复的可能性，可能无法获得完整的分布。

There are many different sources from which relevant information can beobtained for an intelligence task at hand, such as an analysis of operationsplanning by Al Qaeda. The accuracy of this information is frequentlyimperfect. Information obtained from each source is frequently also different instructure and scope. XML has emerged today as the standard for information exchange. Itsflexibility permits the representation of information from heterogeneoussources in a single unified framework.The goal of this project is to manage uncertain (probabilistic) data,represented in XML. While there have been previous efforts to developprobabilistic relational systems, the need for representing and queryinguncertain information is much greater for loosely structured data not readily amenable to a relational representation.XML data poses several modeling challenges that are the focus of thisproject: due to the data having (an inclusion hierarchy) structure,probabilities cannot be assigned independently; due to XML elements occurringat multiple granularities, probabilities may be assigned at multiple levels;due to the possibility of missing and repeated sub-elements, one may not beable to obtain complete distributions.