Semantic and Algorithmic Recognition Support to Porting Software Applications to Cloud - Trustworthy Eternal Systems via Evolving, Software Data and Knowledge - page 11

the parsing (expressed as Prolog clauses) to the set of terminals, non-terminals
and relationships of the Abstract Program Representation .
An overall Abstract Program Representation is generated during the recogni-
tion process. An example is illustrated in Fig. 4.
Fig. 4. Abstract Program Representation
It has the structure of a Hierarchical PDG (HPDG), reflecting the hierarchical
strategy of the recognition process. As long as the parsing process proceeds and
more and more abstract concepts are recognized, they are represented as nodes
in increasingly higher layers of the HDPG. The nodes of this graph are connected
by two kind of edges. The hierarchy edges connect each node representing a con-
cept to the lower layer nodes representing its subconcepts. The graph structure
determined by this kind of edges represents the hierarchy of abstraction; this
structure is generally a tree, excepted in the case of shared concepts, i.e. when
a concept instance is subconcept of more than one concept. The dependence
edges link together nodes that have abstract control and data dependence rela-
tionships between them. Note that, during the recognition process, dependence
edges for the newly created abstract concept nodes are inherited from those of
the composing subconcept nodes in a way that is characteristic of each concept.
4.2 Schema Matcher
A fundamental operation in the manipulation of ontologies is match ,whichtakes
two ontologies as input and produces a mapping between elements of the two
ontologies that correspond semantically. Match plays a central role in numerous