Software Product Line Engineering Basics - Model-Driven and Software Product Line Engineering - page 29

Smart-Home system has one floor with two rooms, the Main
Room and the Living Room . Figure 2.3 presents the Main
Room , which has Air Conditioning as the Environmental
Control , and its door has Fingerprint as the Door Lock
Control .
2.4. Software product line engineering
The Software Engineering Institute (SEI) [CAR 09], which
has been the most important promoter of the software product
line paradigm, provides the following definition of what an
SPL is: “A software product line is a set of software-intensive
systems sharing a common, managed set of features that satisfy
the specific needs of a particular market segment or mission
and that are developed from a common set of core assets in
a prescribed way” [CLE 01]. This definition uses the term
core asset,which are re-usable artifacts considered as building
blocks in SPLE. These re-usable artifacts can be models,
common components,documentation,requirements,test cases,
and so on.
To obtain benefits from the creation of re-usable common
assets, it is important to be able to derive many products from
the assets. In SPLE, the description of the set of products,
which are parts of an SPL, is called the scope of the product
line .To achieve a profitable SPL,its scope must be neither very
large nor very small.To capture the scope of SPLs,product line
architects determine the commonalities,i.e. the characteristics
shared by all products in a product line, and the ways in
which they can vary (variability). If the ratio between the
commonality and the variability is low, then the core assets
will lose their ability to satisfy the variability; economy of
product derivation will be lost, and the product line will fall
into the traditional style of “one-product-per-time”. If the scope
is very small, then the core assets might not be built in a
generic enough way, and the return on investment will never
be achieved [CLE 02a,CLE 01].The management of variability