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parent feature of
StoreFront
. For inclusive and exclusive child features, a class
union is used. For instance, Axiom 3 defines
Basic
and
Advanced
as exclusive
child features of the parent feature
Searching
. The axiom ensures that only one
feature is selected (cf. [6]). Axiom 4 depicts a cross-tree constraint where the
feature
EmailWishList
includes
Registration
.
The solution space is defined by a business process model template. In Def. 2,
we give generic definitions for solution space models. We focus on elements that
are mapped to features, i.e., these elements realize a certain feature. Obviously,
the granularity of mapping solution space models (e.g., classes, attributes) de-
pends on the applications. In the reset of this paper, all elements that are sub-
classes of the BPMN class
Element
canbemappedtofeatures.
Definition 2.
A Solution Space Model
Ω
=
that
could be mapped to features and entities that are not mapped and do not directly
realize features (
S
,
T
consists of entities
S
T
). The sets
S
and
T
are disjoint.
Concrete process models found in the solution space are automatically trans-
formed to a knowledge base
Σ
Ω
. The transformation creates classes for con-
structs of the BPMN metamodel, like the classes
Activity
and
SequenceEdge
,in-
dependently of the concrete BPMN model template. All elements of the BPMN
model template are modeled as subclasses of
Element
(i.e., elements of
S
).
V ertex, Activity, SequenceEdge Element
(5)
RequestW ishList Activity
(6)
E
1
SequenceEdge
(7)
RequestW ishList ∃outgoingEdge.E
1
(8)
Vertex
,
Activity
and
SequenceEdge
are subclasses of
Element
(Axiom 5).
RequestWishList
is a concrete activity, defined by a subclass axiom too (Ax-
iom 6). Likewise, an edge
E1
in the process model is represented by a subclass
axiom (Axiom 7). The relations from activities to edges are described using
existential restrictions on the object property
outgoingEdge
(Axiom 8).
Mappings (Def. 3) connect features
of the solution space
model
Ω
. A feature can be mapped to multiple elements and likewise an element
in the solution space might realize multiple features.
F
and the elements
S
Definition 3.
For a feature model
Φ
=
F
,
F
P
,
F
M
,
F
IOR
,
F
XOR
,
F
cr
and a
solution space model
Ω
=
S
,
T
, a Mapping Model
M
is a relation
M
⊆F×S
,
that is defined as
F×S
:=
{
(
f, s
):
f
∈F∧
s
∈S}
.
Finally, we transform the mapping models into a TBox
Σ
M
. For each mapped
element
E
in
Ω
, we introduce a class
Map
E
that is a subclass of
Map
.
The object property
feature
is used to describe the mappings from elements to
features. A mapping from an element
E
toafeature
F
is represented by an axiom
Map
E
∃
∈S
feature.F
(Axiom 9). The mapping classes
Map
E
are introduced
to separate the feature mapping from the solution space. In order to ease the
validation later on, we define the property
hasF eature
as a subproperty of the
property
feature
form the mapping model (Axiom 10).
