According to the world economic forum report, around 70% of generated data are not used. This limitation of usage is mainly due to the lack of interoperability and linking of data that resides in isolated silos. Indeed, the overwhelming amount of data has worsened heterogeneity problems, as have the types of sources generating data in heterogeneous formats and different semantics. Those data related problematics are frequent in the domain of Earth Observation (EO). Earth observed data use different terminologies, which are difficult to reconcile because they reflect overlapped disciplines. These issues lead to misunderstandings and inefficient exchange and management of data in terms of access, pricing, and data rights, which can hamper environmental phenomena understanding. Virtual Knowledge Graph (VKG), allows semantic integration of existing data sources into a wide Knowledge Graph. In this work we propose a knowledge hypergraph-based approach for data integration and querying, with an application to Earth Observation data. Our proposal takes place in two phases (1) a knowledge hypergraph-based virtual data integration and (2) a hypergraph-based query processing. The first phase allows to generate a virtual knowledge hypergraph consisting of RML mappings between an ontology and the data. The second phase consists of enhancing the user’s query by extracting and consolidating a global view of data from different sources based on the generated knowledge hypergraph. The proposed approach is implemented in the Onto-KIT tool (Ontology-based Knowledge hypergraph data Integration and querying Tool) and evaluated through real use case studies. The obtained results show that our proposal enhances query processing in terms of accuracy, completeness, and semantic richness of response.

中文翻译：

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基于知识超图的数据集成和查询方法：在地球观测中的应用

根据世界经济论坛的报告，大约 70% 的生成数据没有被使用。这种使用限制主要是由于缺乏互操作性和驻留在孤立孤岛中的数据链接。事实上，大量的数据加剧了异构性问题，生成异构格式和不同语义数据的数据源类型也是如此。这些与数据相关的问题在地球观测（EO）领域很常见。地球观测数据使用不同的术语，这些术语很难协调，因为它们反映了重叠的学科。这些问题导致数据在访问、定价和数据权利方面的误解和低效交换和管理，从而阻碍对环境现象的理解。虚拟知识图（VKG）允许将现有数据源语义集成到广泛的知识图中。在这项工作中，我们提出了一种基于知识超图的数据集成和查询方法，并将其应用于地球观测数据。我们的建议分两个阶段进行：（1）基于知识超图的虚拟数据集成和（2）基于超图的查询处理。第一阶段允许生成由本体和数据之间的 RML 映射组成的虚拟知识超图。第二阶段包括通过基于生成的知识超图提取和合并来自不同来源的数据的全局视图来增强用户的查询。所提出的方法在 Onto-KIT 工具（基于本体的知识超图数据集成和查询工具）中实现，并通过实际用例研究进行评估。获得的结果表明，我们的建议在响应的准确性、完整性和语义丰富性方面增强了查询处理。