Annotator User Guide
Revision as of 22:25, 27 September 2011 by Whetzel (talk | contribs) (→Annotator Web Service Response)
Annotator Web service Validation
- Note: All NCBO REST Web services will be required to contain the parameter "apikey=YourApiKey" starting June 2011. The parameter will be added to all Web service calls for the April 27, 2011 release but will not be required until June 2011. To obtain an API key, login to BioPortal and go to "Account" where your API key will be displayed. The addition of the API key replaces the use of the email parameter.
Sample Clients for the Annotator
HTML Client: http://rest.bioontology.org/test_oba.html
Code examples: http://www.bioontology.org/wiki/index.php/Annotator_Client_Examples
Annotator Web service endpoint
- Web service signature: http://rest.bioontology.org/obs/annotator?email=example@example.org
- Type: POST
Annotator Web Service Workflow
The Annotator Web service’s workflow is composed of two main steps (figure):
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First, direct annotations are created from raw text. Annotations are based on syntactic concept recognition using a dictionary compiled from terms (concept names and synonyms) pulled from the ontologies. The Annotator enables the selection of ontologies from one of the largest sets of available biomedical ontologies. We implemented the service using a subset of the BioPortal ontologies which includes 16 ontologies from UMLS (12 in RRF format, 2 in OBO format, 2 in OWL format). These ontologies provide a dictionary of 1,594,785 concepts and 3,200,654 terms.
In the second step, semantic expansion components leverage the semantics in ontologies (e.g., is_a relations and mappings) to create additional annotations. For example, the is_a transitive closure component traverses an ontology parent-child hierarchy to create new annotations with parent concepts of concepts in direct annotations. The ontology-mapping component creates new annotations based on existing mappings between different ontologies. Point-to-point mappings that link concepts one another are defined manually or by automatic algorithms in BioPortal.
The is_a transitive closure expansion component
An is_a transitive closure component traverses an ontology parent-child hierarchy to create new annotations with parent concepts. For instance, if data are annotated with a concept from the NCI Thesaurus, such as melanoma, this component generates a new annotation with the concept skin neoplasm, because the NCI Thesaurus provides the knowledge that melanoma is_a skin neoplasm. The Annotator uses the is_a relations as they are defined by BioPortal in the <SubClass>/<SuperClass> information for a given concept (accessed via REST web service).
The mapping expansion component
An ontology-mapping component creates new annotations based on existing mappings between different ontologies. For example, an annotation done with concept 40644/Melanoma in NCI Thesaurus can be expanded to another one with in SNOMED-CT because the BioPortal provides the mapping information. The Annotator uses the mapping as they are defined by the repositories: BioPortal mappings are defined in the BioPortal front-end and accessed in an ad-hoc manner.
Annotator Web Service Parameters
- See http://www.bioontology.org/wiki/index.php/BioPortal_2.3_Release_Notes for changes in Annotator output and updated information on how to use UMLS ontologies with the Annotator.
The Annotator Web service offers a set of parameters that allows a user to customize the Annotator workflow and filter the result. To customize the workflow and the result, the user can specify a set of ontologies and a specific set of semantic types. Plus, the two steps of the annotation workflow can be parametrized.
The Annotator Web service response time depends on the selected components as each consumes resources at a different level. For example, the is_a transitive closure takes a long time to process, even when using a pre-computed hierarchy table. As another example, an annotation with wholeWordOnly=false will be significantly longer that with wholeWordOnly=true.
Please see below for the list of parameters and the possible values.
| longestOnly | {true, false} | default: false | Specifies either or not the concept recognition step (done with University of Michigan Mgrep tool) must match the longest words only if they are several concepts that match to an expression.
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| wholeWordOnly | {true, false} | default: true | Specifies whether the concept recognition step must match whole words only or not, if they are several concepts that match to a given word.
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| filterNumber | {true, false} | default: true | Specifies whether the concept recognition step to filter numbers or not. |
| stopWords | {stopWord1,...,stopWordN} | default: empty (i.e. none) | Specifies the list of words to exclude from matching. |
| withDefaultStopWords | {true, false} | default: false | Specifies whether to use the default stop words or not. The default stop word list is available from this Web service call: http://rest.bioontology.org/obs/stopwords. If this parameter is set to true, this will override any stopWords provided by the user in the parameter "stopWords". |
| isStopWordsCaseSenstive | {true, false} | default: false | Specifies whether stopwords are case-sensitive or not. |
| minTermSize | {integer} | default: 3 | Specifies the minimum length of the term to be included in the annotations. |
| scored | {true, false} | default: true | Specifies either or not the annotations are scored. A score is a number assigned to an annotation that reflects the accuracy of the annotation. The higher the score is the better the annotation is. The scoring algorithm gives a specific weight to an annotation according to the context of this annotation. For instance, an annotation done by matching a concept preferred name will be given a higher weight than an annotation done by matching a concept synonym or than an annotation done with a parent level 3 in the is_a hierarchy. Details on the scoring algorithm are given in section Scoring algorithm.
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| withSynonyms | {true, false} | default: true | Specifies either or not the direct annotations are done with or without Synonyms. By default it includes all the synonyms and preferred name. If 'false' is selected, the direct annotations are done with only preferred name. |
| ontologiesToExpand | {localOntology1,...,localOntologyN} | default: empty (i.e. all ontologies) | Specifies the list of ontologies to use with the mapping semantic expansion component. The list of ontologies that can be used is available in the sample HTML page. The values are separated with comma (without spaces).
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| ontologiesToKeepInResult | {localOntology1,...,localOntologyN} | default: empty (i.e. all ontologies) | Specifies the list of ontologies to keep in the result of the annotation process. The list of ontologies that can be used is available in the sample HTML page. The values are separated with comma (without spaces).
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| isVirtualOntologyId | {true, false} | default: false | Specifies whether the input values are virtualOntologyId instead of localOntologyid. VirtualOntologyId is not version-specific. |
| semanticTypes | {semanticType1,...,semanticTypeN} | default: empty (i.e. all semanticTypes) | Specifies the list of semantic types to use in the annotation process. The list of semantic types that can be used is available in the sample HTML page. The values are separated with comma (without spaces). Note that the restriction to semantic types is also applied during the semantic expansion steps.
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| levelMax | {integer} | default: 0 | Specifies the maximum level a parent concept must have to be considered for the is_a semantic closure expansion step.
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| mappingTypes | {null,mappingType1,...,mappingTypeN} | default: empty (i.e. all mappingTypes) | Specifies the list of mapping type to use during the mapping expansion step. The list of semantic types that can be used is available in the sample HTML page. The values are separated with comma (without spaces). The current list is described hereafter.
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| textToAnnotate | Specifies the text to be annotated. | ||
| format | {xml,text,tabDelimited} | default: xml | Specifies the desired format of the response from Annotator. For programmatic access, XML is strongly suggested.
The elements of the Annotator response are described in next section. |
Annotator Web Service Response
In this section we define the Annotator Web service model i.e., what the service returns to the user: the objects as well as their relations and the constraints that applies.
Response Content: annotatorResultBean
| resultId | The id of the annotatorResultBean. | ||||||||||||
| dictionary | Dictionary contains the metadata (not the content) of the dictionary used for a result. dictionaryId, dictionaryName, and dictionaryDate identify the dictionary on the server side and give information about its content. Dictionary versioning is strongly linked to the evolution of the ontologies used. Each time ontologies change, the dictionary is updated. All the dictionary information may be useful for comparing results of the Annotator service on time. | ||||||||||||
| statistics | Statistics contains information on the number of annotations done for a given context. The contextName keyword identifies the type of context and nbAnnotation is the number of annotations of this type. | ||||||||||||
| parameters | Parameters summarizes all the parameters specified by the user when requesting the Annotator service. Those parameters are described in previous section. | ||||||||||||
| ontologies | To keep the model simple, we provide only the global ontology identifier, localOntologyId the name (ontologyName) and version (ontologyVersion). This information come from the original repositories (UMLS/BioPortal) and might help the user to select the right ontology to use. When an ontology is used in the annotation, a result has a set of OntologyUsed which specify 2 other properties: nbAnnotation, the number of annotation that have been made with concepts from this ontology. score, the sum of all the scores of the annotations done with concepts from this ontology (if parameter scored=true). Therefore, score represents the most accurate ontology to annotate the given text. | ||||||||||||
| annotations | Annotation is a representation of one annotation. An annotation has a score which represents the accuracy of the annotation computed by the scoring algorithm (if the scored=true parameter was chosen, otherwise score=-1). An annotation is done with a concept in a context.
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