A-QuB-2 | A Web Application for Querying and Exploring Semantic Data

System Description

A-QuB-2 is a web application that facilitates the exploration of semantic (RDF) data by plain users. It offers an intuitive, user-friendly interface that supports users in building and running complex queries step-by-step, without needing to know and write SPARQL. Its configuration model allows setting up the application for use over any knowledge base, independent of the underlying data model / ontology.

The supported functionalities include:

• Assistive query building interface that exploits the connections of the KB entities
• Data filtering based on entity, text, number range, date range, boolean value, map area
• Results visualisation in table
• Results browsing by exploiting the entity interconnections
• Results download in CSV format for further (offline) analysis
• Configuration for use over any KB through a properties file

The system is an extension of a previous version (called A-QuB), described in the following demo paper:

V. Kritsotakis, Y. Roussakis, T. Patkos, M. Theodoridou, "Assistive Query Building for Semantic Data." In SEMANTICS Posters&Demos. 2018 (PDF).

The current version a) implements a configuration model that allows fully configuring the application through a properties file, b) realizes complex JOIN mechanisms on dynamically-defined paths connecting pairs of entities, c) has been extended for supporting additional functionalities, such as filtering by number range, boolean value, date range (including expressions like '20th century', 'decade of 1970', etc.), and others.

Technologies Used

• Spring Boot – A project built on the top of the Spring framework. It provides a simpler and faster way to set up, configure, and run both simple and web-based (Spring Web MVC) applications;
• AngularJS - A structural framework for dynamic web apps based on HTML and JavaScript;
• Material Design & Bootstrap-UI - UI component frameworks;
• H2 – A relational database management system written in Java, that can be embedded in Java applications;

Requirements

• The application communicates with the knowledge base (RDF triplestore) through the API provided by A-QuB AccessServices. The URL of this API is set in the configuration's property file.

Installation Instructions

1. Create the H2 database by running the java command:
   >> java H2Manager.java
2. Prepare an initial configuration by editing the file 'config.properties' (instructions inside the file)
3. The JAR can be created by running the maven command:
   >> mvn package
4. The JAR is executed by running the Java command:
   >> java -jar <Name_Of_The_JAR.jar>
   The port to be used can be defined by using the argument 'server.port', for example:
   >> java -jar <Name_Of_The_JAR.jar> --server.port=8099

Contact

• Fafalios Pavlos (fafalios@ics.forth.gr)

Acknowledgements

The work has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 890861 (Project ReKnow).

The previous version of this work was carried out within the H2020 project VRE4EIC (No 676247).