Ontology repository systems are used for publishing and sharing ontologies and vocabularies for content indexing, information retrieval, content integration, and other purposes. However, interlinking these distributed repositories to provide global search and browsing over the repositories has not been made. In the spirit of Linked Open Data, we propose creating a network of Linked Open Ontology Services (LOOS) consisting of ontology repositories that publish their content using a shared API. To test the approach, we have dened an HTTP API and present a proof-of-concept implementation consisting of three client applications that are used for accessing a LOOS network of over 50 ontology servers, part of the Ontology Library Service ONKI.

1. Thispresentationwasgiven at ORES2010, part of ESWC2010, Crete, May 31st 2010. Read the paper: http://www.seco.tkk.fi/publications/2010/viljanen-et-al-onki-loos-2010.pdf Linked Open Ontology Services Kim Viljanen, Jouni Tuominen, Mikko Salonoja, Eero Hyvönen SemanticComputingResearch Group (SeCo) Aalto University, School of Science and Technology, and University of Helsinki

2. The problemOntology Repositories are separate islands Existing repositories, e.g., Cupboard, BioPortal, ONKI… No connection between repositories E.g., finding all matching concepts located in different repositories is not possible Due to this: Quality of annotation may decrease Redundant new ontologies and concepts may be created Interlinking of data decreases Merging data is more difficult

4. Proof of conceptimplementation

5. GlobalSearchusing LOOS (ONKI2) Test ONKI2 at: www.yso.fi/onki2

6. Discussion Relatedwork Compared to SPARQL: LOOS focuses on ontologies, restrictedqueries Compared to SKOS API, OWL API:LOOS provideshigherabstraction, independentfromspecificontologylanguages Compared to APIsof Bioportal, Swoogle and Watson:Differentgoals. LOOS is aboutcreating a common API, sharedbydifferentservices Compared to existingontologyrepositories: LOOS is a distributedapproachwithontologyspecific UI and serverimplementations Conclusions Ontologyrepositoriesshouldbeaccessible via a common API Wepropose LOOS as the solution LOOS hasbeenimplemented in ONKI, servingover 70 ontologies Hasturned out to be a flexiblesolution (e.g., for creating new UIs) LOOS enablesglobal, uniformaccess to ontologyrepositories