The Ontological Key: Automatically Understanding and Integrating Forms to Access the Deep Web

TL;DR

This paper introduces OPAL, a comprehensive system for automatic understanding and integration of web forms, significantly improving form labeling and interpretation to facilitate deep web access and semantic integration.

Contribution

OPAL is the first approach to combine form labeling and interpretation using rich features and domain schemas, enabling high accuracy and low effort in form understanding.

Findings

OPAL outperforms previous methods in form labeling accuracy.

Achieves over 97% accuracy in form interpretation within target domains.

Successfully translates and distributes master queries across hundreds of forms with no errors.

Abstract

Forms are our gates to the web. They enable us to access the deep content of web sites. Automatic form understanding provides applications, ranging from crawlers over meta-search engines to service integrators, with a key to this content. Yet, it has received little attention other than as component in specific applications such as crawlers or meta-search engines. No comprehensive approach to form understanding exists, let alone one that produces rich models for semantic services or integration with linked open data. In this paper, we present OPAL, the first comprehensive approach to form understanding and integration. We identify form labeling and form interpretation as the two main tasks involved in form understanding. On both problems OPAL pushes the state of the art: For form labeling, it combines features from the text, structure, and visual rendering of a web page. In extensive experiments on the ICQ and TEL-8 benchmarks and a set of 200 modern web forms OPAL outperforms previous approaches for form labeling by a significant margin. For form interpretation, OPAL uses a schema (or ontology) of forms in a given domain. Thanks to this domain schema, it is able to produce nearly perfect (more than 97 percent accuracy in the evaluation domains) form interpretations. Yet, the effort to produce a domain schema is very low, as we provide a Datalog-based template language that eases the specification of such schemata and a methodology for deriving a domain schema largely automatically from an existing domain ontology. We demonstrate the value of the form interpretations in OPAL through a light-weight form integration system that successfully translates and distributes master queries to hundreds of forms with no error, yet is implemented with only a handful translation rules.