Hybrid XML Retrieval: Combining Information Retrieval and a Native XML Database

TL;DR

This paper presents a hybrid XML retrieval system that combines full-text search and native XML database techniques, significantly improving retrieval effectiveness over individual systems in the INEX 2003 benchmark.

Contribution

The paper introduces a novel hybrid retrieval approach that dynamically selects retrieval units called 'Coherent Retrieval Elements' for improved XML document retrieval.

Findings

Hybrid system outperforms individual systems in effectiveness.

Dynamic retrieval unit selection enhances retrieval robustness.

System shows significant improvements on INEX 2003 data.

Abstract

This paper investigates the impact of three approaches to XML retrieval: using Zettair, a full-text information retrieval system; using eXist, a native XML database; and using a hybrid system that takes full article answers from Zettair and uses eXist to extract elements from those articles. For the content-only topics, we undertake a preliminary analysis of the INEX 2003 relevance assessments in order to identify the types of highly relevant document components. Further analysis identifies two complementary sub-cases of relevance assessments ("General" and "Specific") and two categories of topics ("Broad" and "Narrow"). We develop a novel retrieval module that for a content-only topic utilises the information from the resulting answer list of a native XML database and dynamically determines the preferable units of retrieval, which we call "Coherent Retrieval Elements". The results of our experiments show that -- when each of the three systems is evaluated against different retrieval scenarios (such as different cases of relevance assessments, different topic categories and different choices of evaluation metrics) -- the XML retrieval systems exhibit varying behaviour and the best performance can be reached for different values of the retrieval parameters. In the case of INEX 2003 relevance assessments for the content-only topics, our newly developed hybrid XML retrieval system is substantially more effective than either Zettair or eXist, and yields a robust and a very effective XML retrieval.