REX: Web-Scale Extension of RDF Knowledge Bases

REX is an RDF extraction framework for Web data that can learn XPath wrappers from unlabelled Web pages using knowledge from the Linked Open Data Cloud.

API Documentation Issues Source Code Wiki

Introduction

The Web RDF Extraction Framework, REX, addresses the problem of extracting RDF data from templated websites. To this end, REX provide a generic architecture that allows learning XPath wrappers from unlabelled Web pages using knowledge from the Linked Open Data Cloud. REX is to be regarded as a skeleton that is to be fleshed out for your purposes. Still, REX is also a running system as it provides running implementations for all of its interfaces.

In contrast to existing frameworks to RDF extraction using XPath wrappers, REX provides a consistency layer which ensure that the new knowledge extracted is logically consistent with the knowledge already available in the input knowledge base. This website gives an overview of the framework. All technical details can be found on the Github page's wiki. There you will also find:

  • The Java documentation for the coders out there.
  • A manual to help you run the framework before you customize it for your purposes.
  • A ticket system in case you find some bugs or have some feature request.

Architecture

The REX Architecture

To facilitate the implementation of extraction processes, the framework provides the four layer-architecture shown in Figure 1. The data for the extraction is first to be gathered from the Web (or any other source of your choice). To this end, interfaces are provided. Each of the modules in each of the layers is provided as an interface. Moreover, an initial implementation of each interface is provided (see Java Docs).

  • The extraction layer allows for gathering data from the Web and consists of two modules: The crawler gathers website content from the Web while the domain identifier helps detecting web site domains that contain information pertaining to a given property.
  • The storage layer provides interfaces for managing and storing structured data as well as unstructured data.
  • The induction layer contains all modules that allow to learn XPath expressions. The core module here is the XPath Learner.
  • The generation layer allows integration approaches for generating and validating RDF data. The default generator relies on AGDISTIS and ORE.

Evaluation

With REX, we also aimed to provide a baseline system for the extraction of RDF from templated websites. Thus, in addition to providing at least one implementation for all the interfaces, we also evaluated the basic REX. The data we used for the evaluation can be found here.

What next?

There are several things you can do.

  1. Run REX: Simply follow the steps in the manual.
  2. Extend REX: Please check out the installation instructured.
  3. Point out bugs: Please use the issue tracker.

Now you're on. Please extend REX and help improving the extraction of RDF from the Web.

Project Team

Former Members

Publications

by (Editors: ) [BibTex of ]

News

DBpedia Knowledge Engineering PhD Symposium ( 2022-05-02T16:59:37+02:00 by Julia Holze)

2022-05-02T16:59:37+02:00 by Julia Holze

Dear all,  We are excited to invite you to the 1st DBpedia Knowledge Engineering PhD Symposium, organized on July 6th, 2022 in Leipzig, Germany. Read more about "DBpedia Knowledge Engineering PhD Symposium"

Tutorial @ Knowledge Graph Conference 2022 ( 2022-04-25T12:24:06+02:00 by Julia Holze)

2022-04-25T12:24:06+02:00 by Julia Holze

On May 2, 2022 we will organize a tutorial 2.0 at the Knowledge Graph Conference (KGC) 2022. Read more about "Tutorial @ Knowledge Graph Conference 2022"

International Workshop on Data-driven Resilience Research 2022 ( 2022-04-21T14:43:27+02:00 by Julia Holze)

2022-04-21T14:43:27+02:00 by Julia Holze

In the face of continuously changing contextual conditions and ubiquitous disruptive crisis events, the concept of resilience refers to some of the most urgent, challenging, and interesting issues of nowadays society. Read more about "International Workshop on Data-driven Resilience Research 2022"

DBpedia @ Google Summer of Code Program 2022 ( 2022-03-23T14:26:48+01:00 by Julia Holze)

2022-03-23T14:26:48+01:00 by Julia Holze

DBpedia, one of InfAI’s community projects, will be part of the 11th Google Summer of Code (GSoC) program. The GSoC program has the goal to bring students from all over the globe into open source software development. Read more about "DBpedia @ Google Summer of Code Program 2022"

DBpedia Tutorial @ The Web Conference 2022 ( 2022-03-16T13:52:16+01:00 by Julia Holze)

2022-03-16T13:52:16+01:00 by Julia Holze

Dear all, We are proud to announce that we will organize an online tutorial at the Web Conference on 25th of April 2022. A particular focus will be put on the DBpedia Infrastructure, i.e. Read more about "DBpedia Tutorial @ The Web Conference 2022"