Concept-based Query Expansion and Construction

We develop a deductive data model for concept-based query expansion. It is based on three abstraction levels: the conceptual, linguistic and string levels. Concepts and relationships among them are represented at the conceptual level. The linguistic level gives natural language expressions for concepts. Each expression has one or more matching patterns at the string level. The models specify the matching of the expression in database indices built in varying ways. The data model supports a declarative concept-based query expansion and formulation tool, the ExpansionTool, for heterogeneous IR system environments. Conceptual expansion is implemented by a novel intelligent operator for traversing transitive relationships among cyclic concept networks. The number of expansion links followed, their types, and weights can be used to control expansion. A sample empirical experiment illustrating the use of the ExpansionTool in IR experiments is presented.