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266 PART THREE CONVENTIONAL METHODS FOR SOFTWARE ENGINEERING

FIGURE 10.8 Top-level archectecture flow diagram (AFD)
Building an
SFD hierarchy

A B

AFD for A

AFD for B

C

AFD for C

Business process engineering is a system engineering approach that is used to
define architectures that enable a business to use information effectively. The intent
of business process engineering is to derive comprehensive data architecture, appli-
cation architecture, and technology infrastructure that will meet the needs of the busi-
ness strategy and the objectives and goals of each business area. Business process
engineering encompasses information strategy planning (ISP), business area analysis
(BAA), and application specific analysis that is actually part of software engineering.
Product engineering is a system engineering approach that begins with system
analysis. The system engineer identifies the customer's needs, determines economic
and technical feasibility, and allocates function and performance to software, hard-
ware, people, and databases—the key engineering components.
System engineering demands intense communication between the customer and
the system engineer. This is achieved through a set of activities that are called require-
ments engineering—elicitation, analysis and negotiation, specification, modeling, val-
idation, and management.
After requirements have been isolated, a system model is produced and repre-
sentations of each major subsystem can be developed. The system engineering task
culminates with the creation of a System Specification—a document that forms the
foundation for all engineering work that follows.