
38 Big Data Computing
and possibly overlapping environmental contexts need to be regarded in
a hierarchy which corresponds to several subject domains of intetrest and
afoundational knowledge layer. By saying this, we subsume that there is a
single domain or foundational ontology module schema per environmental
context. Different environmental contexts corresponding to different subject
domais of interest are pictured as ellipses in Figure 1.7.
Environmental contexts are sowed with knowledge tokens that corre-
spond to their subject domains. It might be useful to limit the lifetime of a
knowledge token in an environment—those which ...