Influence of Event Specialization Strategy on Some Aspects of Natural Language Querying Interfaces to Ontologies

Abstract

The performance characteristics and certain maintenance aspects of a natural language querying (NLQ) interface depend on how the data model is conceptualized. One of the areas where alternative conceptualizations are available is events and their specialization. The concept of event specialization is already known from event extraction methods, which allows for a more precise description of the events identified in a text. In the context of NLQ interfaces, event specialization allows narrower or broader questions. This study investigates how the choice of event specialization strategy in OWL (Web Ontology Language) ontologies affects the complexity and performance-related aspects of the NLQ interface to ontologies. In this paper, we present four event specialization strategies and investigate how they impact the size of the ontology schema and vocabulary of the NLQ interface, the performance of querying and data import, the size of the semantic repository, and the complexity of SPARQL queries. We discuss the strengths and weaknesses of each approach and present recommendations on determining the best one for the needs of NLQ interface end-users and developers.

Keywords

• Natural language query (NLQ) interface
• event ontology
• event representation
• n-ary relation
• event specialization strategy
• OWL