MetaStore: an adaptive metadata management framework for heterogeneous metadata models

Abstract

In this paper, we present MetaStore, a metadata management framework for scientific data repositories. Scientific experiments are generating a deluge of data, and the handling of associated metadata is critical, as it enables discovering, analyzing, reusing, and sharing of scientific data. Moreover, metadata produced by scientific experiments are heterogeneous and subject to frequent changes, demanding a flexible data model. Existing metadata management systems provide a broad range of features for handling scientific metadata. However, the principal limitation of these systems is their architecture design that is restricted towards either a single or at the most a few standard metadata models. Support for handling different types of metadata models, i.e., administrative, descriptive, structural, and provenance metadata, and including community-specific metadata models is not possible with these systems. To address this challenge, we present MetaStore, an adaptive metadata management framework based on a NoSQL database and an RDF triple store. MetaStore provides a set of core functionalities to handle heterogeneous metadata models by automatically generating the necessary software code (services) and on-the-fly extends the functionality of the framework. To handle dynamic metadata and to control metadata quality, MetaStore also provides an extended set of functionalities such as enabling annotation of images and text by integrating the Web Annotation Data Model, allowing communities to define discipline-specific vocabularies using Simple Knowledge Organization System, and providing advanced search and analytical capabilities by integrating the ElasticSearch. To maximize the utilization of the data models supported by NoSQL databases, MetaStore automatically segregates the different categories of metadata in their corresponding data models. Complex provenance graphs and dynamic metadata are modeled and stored in an RDF triple store, whereas the static metadata is stored in a NoSQL database. For enabling large-scale harvesting (sharing) of metadata using the METS standard over the OAI-PMH protocol, MetaStore is designed OAI-compliant. Finally, to show the practical usability of the MetaStore framework and that the requirements from the research communities have been realized, we describe our experience in the adoption of MetaStore for three communities.