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GATE Change log

The Idea

The NeOn Toolkit incorporates a change log management system which allows the managing of changes made by users in a collaborative environment. This is necessary because different people, who may be experts in their domain, sometimes end up making changes to the same ontology, often at distributed locations. Where it is not possible to have access to a shared repository, other people wishing to make changes to the same ontology have to wait for others to finish their tasks. Changes made to an ontology can involve additions, deletions and modifications.

The basic idea behind producing a change log is to allow people to share their changes with others and thus collaborate on manipulating ontology data. This essentially allows them to work independently as well as simultaneously on the same ontology. However, some ontologies can be extremely large and unwieldy, whereas the changes made to such ontologies may be only very minor. Instead of exchanging different versions of ontologies, it makes it easier to exchange change logs which can then be applied over to the original ontology to get the modified version.

As part of NeOn, we have developed a system that allows the sharing of GATE Ontology Service (GOS) change logs with the NeOn Toolkit. The system works in both directions, not only does it produce a change log for GATE which is compatible with the NeOn Toolkit, but it also supports interpreting it and applying the changes produced by the NeOn Toolkit change log system to an ontology stored in GOS. Given this setup, users can choose to work on a system of their choise (NTK or GOS) and produce a change log that can be interpreted by both the toolkit and GOS to bring the ontologies in the same state.

Download and installation

You can get the sources by carrying out the following steps.
  1. Download a copy of the latest GATE from here.
  2. Download the OWLIM zip file from here.
  3. Unzip this file to replace the Java files in your src/gate/creole/ontology/owlim folder.
  4. Rebuild GATE by calling "bin/ant all".
You can generate and export change logs using the following steps.
  1. Start Gate by callling ``bin/ant run''.
  2. Load the "Ontology Tools" plugin.
  3. Right click on the "Language Resources" and select the "OWLIM Ontology LR". This will bring up a window that will allow you to load an ontology. More information on how to use this Language Resource is available here
  4. As you make changes in the ontology, the changes are recorded in the background. For this prototype only, the changes are recorded in memory. You can download these changes any time by right clicking on the instance of ontology under "Language Resources" and selecting the "Export Neon Change Log" option. When asked, select a location and filename to save the changes to a file. This file is an ontology itself which can be loaded in the same way that other ontologies are loaded in GATE.
  5. In order to test the application of change logs, close GATE and repeat the steps from 1 to 3. This will load the original ontology. In order to apply the previously saved change log, right click on the instance of ontology under "Language Resources" and select the "Load Neon Change Log" option. When asked, select the change log and click on the "Open" button. The changes in the change log will be applied and the editor will refresh it to show you modified ontology.

Technical support

Since the software forms part of the GATE architecture, it is supported by the regular GATE support infrastructure. This is detailed more explicitly on the GATE website. Further information and detailed documentation about GATE can be found in the GATE User Guide and questions about GATE can be addressed to the GATE Users mailing list.


The software is part of GATE and is therefore available under the LGPL licence and is available to use for both commercial and research purposes.


This software is produced as part of the NeOn project. Material produced within NeOn may include information, software and/or media (individually and collectively the "Information"). The Information is made available by the NeOn Consortium and its partner organisations. Our goal is to keep this information timely and accurate. If errors are brought to our attention, we will try to correct them in line with the recommendations contained in the Quality Assurance Plan. However, the NeOn Consortium may accept no responsibility or liability whatsoever with regard to the Information. This information is:

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