Information Technology Reference
In-Depth Information
Figure 7.6
caGrid service metadata.
in Figure 7.6. The service discovery component locates caGrid services
by querying Index Service. It provides three types of querying methods
leveraging caGrid's metadata and indexing infrastructure:
1. String-based querying performs free text searching in service
descriptions. For example, one can search for services whose
descriptions contain string “
array
.”
2. Property-based querying performs search towards predefined
service properties, for example, to locate services
hosted
by
NCICB
that stands for the NCI Center for Bioinformatics, or
whose
name
is
CaArraySvc
.
3. Semantic-based querying. caGrid uses an ontology called NCI
Enterprise Vocabulary Services (EVS) to annotate services and
their associated data. A vocabulary item in EVS is called a
Concept
, and the
Concept Code
is used to uniquely identify it.
A semantic-based approach allows users to locate services that
are annotated with some concept code, for example,
C44282
representing concept
Microarray
.
Consider a service discovery example in Figure 7.7, to search
services whose description contains
array
, hosted by
NCICB
, and
annotated with concept code
C44282
.
