The increasing number of methods available for schema matching/ontology integration suggests the need to establish a consensus for evaluation of these methods. Since 2004, OAEI organizes evaluation campaigns aiming at evaluating ontology matching technologies (see http://oaei.ontologymatching.org/2004/Contest/, http://oaei.ontologymatching.org/2005, http://oaei.ontologymatching.org/2006, and http://oaei.ontologymatching.org/2007).
The OAEI 2008 campaign is associated to the ISWC Ontology matching workshop to be held at Karlsruhe, Germany on Sunday October 26, 2008.
This year's campaign consists of four tracks gathering eight data sets and different evaluation modalities.
We summarize below the variation between the results expected by these tests (all results are given in the Alignment format):
| test | language | relations | confidence | Modalities | Language | Size |
| benchmarks | OWL | = | [0 1] | open | EN | (36+61)*2*49 |
| anatomy | OWL | = | [0 1] | blind | EN | 3k*3k |
| fao | OWL | = | 1 | expert | EN+FR+ES | |
| directory | OWL | = | 1 | blind | EN | |
| mdirectory | OWL | = | 1 | blind | EN+JP | |
| library vlcr | SKOS +OWL | exactMatch, narrowMatch, broadMatch | 1 | blind | EN+DU | |
| conference | OWL-DL | =, <= | [0 1] | blind+consensual | EN |
Each data set has a different evaluation process. They can be roughly divided into four groups:
However, the evaluation will be processed in the same three successive steps as before.
Ontologies are described in OWL-DL and serialized in the RDF/XML format. The expected alignments are provided in the Alignment format expressed in RDF/XML.
The ontologies and alignments of the evaluation are provided in advance during the period between May 19th and June 15th. This gives potential participants the occasion to send observations, bug corrections, remarks and other test cases to the organizers. The goal of this primary period is to be sure that the delivered tests make sense to the participants. The feedback is important, so all participants should not hesitate to provide it. The tests will certainly change after this period, but only for ensuring a better participation to the tests. The final test base has been released on July 1st.
During the execution phase the participants will use their algorithms to automatically match the ontologies. Participants should only use one algorithm and the same set of parameters for all tests in all tracks. Of course, it is fair to select the set of parameters that provide the best results (for the tests where results are known). Beside the parameters the input of the algorithms must be the two provided ontology to match and any general purpose resource available to everyone (that is no resourse especially designed for the test). In particular, participants should not use the data (ontologies and results) from other test sets to help their algorithm. And cheating is not fair...
The deadline for delivering final results is September 26th, sharp. However, it is highly advised that participants send results before (preferably by September 1st) to the organisers so that they can check that they will be able to evaluate the results smoothly and can provide some feedback to participants.
Participants will provide their alignment for each test in the Alignment format. The results will be provided in a zip file containing one directory per test (named after its number) and each directory containing one result file in the RDF/XML Alignment format with always the same name (e.g., participant.rdf replacing "participant" by the name you want your system to appear in the results, limited to 6 alphanumeric characters). This should yield the following structure:
participant.zip +- benchmarks | +- 101 | | +- participant.rdf | +- 103 | | +- participant.rdf | + ... +- anatomy | +- 1 | | +- participant.rdf | +- 2 | | +- participant.rdf | +- ... +- directory | +- 1 | | +- participant.rdf | + ... + ...
Participants will also provide, for September 26th, a paper to be published in the proceedings and a link to their program and parameter set.
The only interesting alignments are those involving classes and properties of the given ontologies. So the alignments should not align individuals, nor entities from the external ontologies.
The organizers will evaluate the results of the algorithms used by the participants and provide comparisons on the basis of the provided alignments.
In order to ensure that it will be possible to process automatically the provided results, participants are requested to provide (preliminary) results by September 1st. In the case of blind tests only the organizers will do the evaluation with regard to the withheld alignments. In the case of double blind tests, the participants will provide a version of their system and the values of the parameters if any.
An email with the location of the required zip files must be sent to the contact addresses below.
The standard evaluation measures will be precision and recall computed against the reference alignments. For the matter of aggregation of the measures we will use weighted harmonic means (weight being the size of reference alignment). Precision/recall graphs will also be computed, so it is advised that participants provide their results with a weight to each correspondence they found (participants can provide two alignment results: <name>.rdf for the selected alignment and <name>-full.rdf for the alignment with weights.
Furthermore, it is planned to introduce new measures addressing some limitations of precision and recall. These will be presented at the workshop discussion in order for the participants to provide feedback on the opportunity to use them in a further evaluation.
From the results of the experiments the participants are expected to provide the organisers with a paper to be published in the proceedings of the workshop. The paper must be no more than 8 pages long and formatted using the LNCS Style. To ensure easy comparability among the participants it has to follow the given outline. A package with LaTeX and Word templates is made available here. The above mentionned paper must be sent in PDF format by September 26th to Pavel Shvaiko (pavel (à) dit dot unitn dot it) with copy to Jerome . Euzenat (à) inrialpes . fr.
Participants may also submit a longer version of their paper, with a length justified by its technical content, to be published online in the CEUR-WS collection and on the OAEI web site (this last paper will be due just before the workshop).
The outline of the paper is as below (see templates for more details):
These papers are not peer-reviewed and are here to keep track of the participations and the description of matchers which took part in the campaign.
The results from both selected participants and organizers will be presented at the Workshop on Ontology matching at ISWC 2008 taking place at Karlsruhe (Germany) on October, 26th, 2008. We hope to see you there.
Here are some tools that may help participants.
Participants may use the Alignment API for generating and manipulating their alignments (in particular for computing evaluation of results).
The participants may use various options if they need to convert SKOS vocabularies into OWL.
Vassilis Spiliopoulos pointed out to Altova transformer from OWL to N3 notation. This can be useful for some. This is a commercial tool with a 30 days free trial.