LODVader: Visualization, Analytics and DiscovEry in Real-time

This is the source code of LODVader API. For the front end repository, please access: https://github.com/cirola2000/LODVader-webpage

For more details and a working demo, check our webpage: http://lodvader.aksw.org

Software Requirements

1 - This project uses MongoDB to save relevant metadata for creation of linksets. The MongoDB default installation is sufficient: sudo apt-get install mongodb-server.

2 - To compile and run the project, you need maven. To install, please use apt-get: sudo apt-get install maven (version > 3.x).

3 - After cloning the project git clone https://github.com/AKSW/LODVader.git, please access the folder ./resources/config.properties and:

3.1 - edit the MongoDB authentication.

3.2 - change the "BASE_PATH" for the directory that LODVader will store data.

4 - LODVader uses GridFS to store Bloom Filters. This means that your database might grow a lot! Ensure the variable "dbpath" in the /etc/mongodb.conf file is setted to the right place.

Hardware Requirements

The minimum hardware requirement to have an acceptable performance is:

• Quad-core processor (recommended octa-core)
• 16GB RAM (recommended 32GB)
• a super fast SSD drive

How to use

Installation process

After cloning the project, open the project root folder and type: mvn clean install. Maven will then download all dependencies and compile the project.

Starting Jetty server

Before run LODVader, be sure that your JVM will have enough heap space to grow. Here, we allow to use 28gb of RAM: export MAVEN_OPTS="-Xmx28g"

To run the API you need to start the Jetty server using mvn jetty:start, and the server must be accessible at the address: http://localhost:9090/LODVader/.

A good starting point is adding a VoID, DCAT or DataID file to LODVader using the API: http://localhost:9090/LODVader/api?addDataset=http://lod-cloud.net/data/void.ttl&rdfFormat=ttl.

To check you datasets status, you can access: http://localhost:9090/LODVader/api?datasetStatus=http://lod-cloud.net/data/void.ttl

Finally, you can access the RDF data about the discovered linksets via: http://localhost:9090/LODVader/api?retrieveDataset=http://lod-cloud.net/

To use visualize the LODVader diagram, you can use our front end available in the repository: https://github.com/cirola2000/LODVader-webpage.