Mapping reuse for meta-querier customization

The primary goal of this dissertation is to investigate the methodologies for developing a system framework that supports the customization of meta-queriers over the Web. Meta-queriers facilitate effective information retrieval from multiple and heterogeneous data sources that are accessible only through query interfaces. They are virtual data integration systems that shield users from data heterogeneity and sources locations. Due to the ever-increasing number of available data sources and sophistication of users, it is highly desirable (and in many cases necessary) to allow for customization of meta-queriers based on users’ preferences (or necessity). Customization comes with some cost: the scalability of the underlying system and the complexity of human-machine interaction. This dissertation investigates new open research issues for the implementation of meta-queriers with respect to customization. There are two aspects of the scalability issue: a potentially large number of customized meta-queriers and a large repository that stores mapping information between entities in different data sources for interoperability. The complexity of human-machine interaction is resulted from the need for collaboration in sharing the mapping information. The proposed approach and the innovation is that it tackles both the scalability and complexity problems holistically through a system framework based on a synergetic combination of two concepts: a community-driven collaborative meta-querier construction and an ontology-based sharing of meta-querier components.Meta-queriers are domain-specific. Domain users constitute a loose community with some common interest and might need to collaborate. In our solution approach, we turn the challenge of the need for human collaboration into opportunities, that is, the scalability problem can be alleviated through the distribution of the meta-querier construction workload by harvesting the human power (assistance) in the community. Another very significant challenge-to-opportunity is the reuse potential from a possibly large scale of existing meta-querier and their components. The innovation in our ontology-based mapping repository is its ability to fully exploit the impact of reuse for human-friendly construction and maintenance of meta-queriers.