Linked Open Data (LOD) has been proliferated over various domains, however, there are still lots of open data in various format other than RDF, a standard data description framework in LOD. These open data can also be connected to entities in LOD when they are associated with URIs. Document-centric XML data are such open data that are connected with entities in LOD as supplemental documents for these entities, and to convert these XML data into RDF requires various techniques such as information extraction, ontology design and ontology mapping with human prior knowledge. To utilize document-centric XML data linked from entities in LOD, in this paper, a SPARQL-based seamless access method on RDF and XML data is proposed. In particular, an extension to SPARQL, XQueryFILTER, which enables XQuery as a filter in SPARQL is proposed. For efficient query processing of the combination of SPARQL and XQuery, a database theory-based query optimization is proposed. Real-world scenario-based experiments in this paper showcase that effectiveness of XQueryFILTER and efficiency of the optimization.

中文翻译：

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SPARQL 与基于 XQuery 的过滤

链接开放数据（LOD）已经在各个领域激增，但是，除了 RDF（LOD 中的标准数据描述框架）之外，仍然存在大量各种格式的开放数据。当这些开放数据与 URI 相关联时，它们也可以连接到 LOD 中的实体。以文档为中心的 XML 数据是与 LOD 中的实体连接的开放数据，作为这些实体的补充文档，将这些 XML 数据转换为 RDF 需要各种技术，如信息提取、本体设计和具有人类先验知识的本体映射。为了利用从LOD中的实体链接的以文档为中心的XML数据，本文提出了一种基于SPARQL的RDF和XML数据无缝访问方法。特别是，提出了 SPARQL 的扩展 XQueryFILTER，它使 XQuery 作为 SPARQL 中的过滤器。针对SPARQL与XQuery结合的高效查询处理，提出了一种基于数据库理论的查询优化方法。本文中基于实际场景的实验展示了 XQueryFILTER 的有效性和优化的效率。