[Pellet-users] ANN: Pellet 1.5

[Evren Sirin]

Pellet users,

We are pleased to announce the release of Pellet 1.5 which you can 
download from the Pellet download page:
http://pellet.owldl.com/download/

The major changes that have been incorporated after 1.5-RC1 are as follows:

* Updated libraries: Jena libraries have been updated to Jena 2.5.3 and 
OWLAPI has been updated to latest SVN snapshot

* Incremental reasoning: Support for incremental reasoning has been 
extended so it is usable through not only OWLAPI interface but also Jena 
interface

* Bug fixes: Improvements for Pellet configuration (especially w.r.t. 
query answering) and bug fixes that have been reported after 1.5-RC1. 
you can find more detailed information about these changes in [1].

This release includes all the improvements that were in 1.5-RC1:

* Optimized classifier: Classifier with a better performance for all 
ontologies and also incorporates the CD optimization to handle large 
taxonomic ontologies very efficiently, e.g. classification time for NCI 
ontology [2] reduced from 45min to 15sec.

* Axiom tracing: Axiom tracing is integrated into this version so a 
single justification can be computed for arbitrary inferences, e.g. 
subclass relations. It can also be used for debugging unsatisfiable 
concepts.

* Incremental reasoning: Some preliminary support for incremental 
reasoning with changing ontologies. After an ontology change, the 
previous reasoning results are reused to improve the performance of 
consistency checking. Currently only ABox additions are supported for 
incremental reasoning.

We would also like to mention couple of things we are working on Pellet 
right now to give you an idea what you can expect in future releases:

* Improved rules support: We are working on improving the DL-safe rules 
support in Pellet to handle datatype properties and built-in functions, 
e.g. numeric comparison and arithmetic operations. Improvements to the 
performance of reasoning with rules are also going on.

* Incremental classification: We are continuing our collaboration with 
NCI and now working on to implement the incremental classification 
service. This service will improve the current incremental reasoning 
support in Pellet (which handles only ABox changes) to handle TBox and 
RBox changes. This enhancement aims to update the classification 
hierarchy incrementally as the ontology is updated instead of 
recomputing the class hierarchy from scratch. You can find more details 
about our approach in the upcoming ISWC paper [3].

It is important to emphasize that these are both work in progress with 
no specific release deadline. We will make more announcements in the 
mailing list and on our blog [4] as we make progress to releasing any of 
these features.

Cheers,
Evren

[1] http://cvsdude.com/trac/clark-parsia/pellet-devel/report/6
[2] http://www.mindswap.org/2003/CancerOntology/nciOncology.owl
[3] History Matters: Incremental Ontology Reasoning Using Modules 
Bernardo Cuenca Grau, Yevgeny Kazakov, Christian Halaschek-Wiener, The 
6th International Semantic Web Conference (ISWC 2007), 2007. To Appear.
[4] http://clarkparsia.com/weblog/