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SKR Homepage Logo link to UMLS Metathesaurus Information link to UMLS Semantic Network Information link to SPECIALIST Lexicon Information link to MetaMap Information link to Medical Text Indexer (MTI) Information link to Medical Text Indexer (MTI) Information link to Medical Text Indexer (MTI) Information link to SemRep Information link to SemRep Information link to SemRep Information SKR Logo:Semantic Knowledge Representation Homepage

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Please Note: We are transitioning!
October 31, 2013:
The URL/website is transitioning. We are making a purely administrative change moving the
Scheduler under the Indexing Initiative umbrella and creating a new dedicated Semantic Knowledge Representation Project web site.

The Indexing Initiative is focused on mapping biomedical free text to UMLS Metathesaurus concepts using MetaMap and indexing MEDLINE articles using the NLM Medical Text Indexer (MTI), while the Semantic Knowledge Representation Project focuses on extracting semantic relations from biomedical text using SemRep and exploiting these relations for applications such as automatic summarization and literature-based discovery.

During this transition all existing links, APIs, and programs will continue to work with the URL. All of the original functionality of the site is still available via the two new web sites. We are hoping to slowly migrate all users over to the new URLs during the next six months or so.

We are sorry for any inconvenience during this time of transition and ask that you update your bookmarks and links to reflect the new URLs. If you have any questions or concerns during this time period, please contact us at

If you are experiencing problems accessing the web sites, please contact us at:
     For SemRep issues:
     For MetaMap or Indexing Initiative issues:
Interactive Mode Web API NEW: Scheduler Home
Batch Mode Batch Status Window NEW: The Semantic Knowledge Representation Project Home

The Semantic Knowledge Representation Project:
This link will take you to the web site for the Semantic Knowledge Representation Project. The new Semantic Knowledge Representation Project web site will provide you with the information on all of the research, publications, tools, and personnel associated with the Semantic Knowledge Representation Project in a much richer and more up-to-date environment solely dedicated to the project.

The Scheduler:
The Scheduler is moving under the Indexing Initiative umbrella. All of the existing functionality will still be available including the Interactive and Batch facilities and API. All of the access to our tools (MetaMap, MTI, and SemRep) will also still be available.

The publications from the site have been separated into their respective projects. We have provided links below for each of the existing areas.

Last Modified: January 22, 2018 ii-public2
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Links to Our Sites
MetaMap Public Release
NEW: Distributable version of the actual MetaMap program.
Indexing Initiative (II)
Investigating computer-assisted and fully automatic methodologies for indexing biomedical text. Includes the NLM Medical Text Indexer (MTI).
Semantic Knowledge Representation (SKR)
Develop programs to provide usable semantic representation of biomedical text. Includes the MetaMap and SemRep programs.
MetaMap Transfer (MMTx)
Java-Based distributable version of the MetaMap program.
Word Sense Disambiguation (WSD)
Test collection of manually curated MetaMap ambiguity resolution in support of word sense disambiguation research.
MEDLINE Baseline Repository (MBR)
Static MEDLINE® Baselines for use in research involving biomedical citations. Allows for query searches and test collection creation.
Structured Abstracts (SA)
Information about NLM's research on Structured Abstracts in the MEDLINE® Baselines.
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