Page 161 - DCAP405_SOFTWARE_ENGINEERING

Software Engineering

Notes with their environments in order to survive Understanding these interactions are essential
for understanding their properties and behavior.

Animate systems are living systems. “Life” has been defined in many different Ways. The
definition now most widely accepted by biologists involves the ways concept autopsies:
“The maintenance of units and wholeness, while components themselves are being
continuously or periodically disassembled and rebuilt, created and decimated, produced
and consumed.” (Zeleny, 1981, p. 5)
From this definition it follows that social and ecological systems are also alive. (Many
biologists are unhappy about this consequence of their definition of ‘life.’)
3. Social Systems: These are systems that (1) have purposes of their own, (2) consist of parts
at least some of which are animate, hence have purposes of their own, and (3) are a part of
one or more larger (containing) systems that may have purposes of their own and that
may contain other social systems. For example, a local government viewed as a social
system is part of a state government, which is also a social system, This, in turn, is part of
a national government. Social systems can be and usually are nested.
4. Ecological Systems: Such systems contain mechanistic, animate, and social systems as
parts and, therefore, containing some parts that have purposes of their own. However,
these systems as a whole are conceptualized as having no purpose of their own. Nature, of
course, is commonly taken to be an ecological system as is our environment.

Ecological systems serve the purposes of their animate and social parts, and provide necessary
inputs to these and open deterministic systems. They also provide a receptacle for their waste as
well as their useful products. Such service and support is their function. An ecological system
can be affected mechanistically by the mechanical or purposeful behavior of its parts. For example,
the purposeful use by people of fluorocarbons as a propellant and the emissions of power plants
affect the ozone layer mechanistically.
Animate and social systems are frequently confronted with situations in which their choices can
affect their effectiveness, either positively or negatively. Such situations are problematic.

Task Problems are situations in which a system’s choice can make a significant difference
to that system. Analyze.

Modeling and Simulation Process

An outline of the essential steps involved in carrying out a modelling and simulation study is
provided in the discussion that follows. Although the initial steps can be effectively presented
using various notions that have been previously introduced, there are several aspects of the
latter stages that require extensive elaboration. This is provided in the discussions that follow.
An overview of the process is provided in Figure 9.11.

The overview of Figure 9.11 does not include a preliminary phase during which solution
alternatives for the problem are explored and a decision is made to adopt a modelling and
simulation approach. We note that the option of also carrying out other complementary
approaches is entirely reasonable and is often prudent for some portions of the problem. Although
this preliminary phase is not explicitly represented in Figure 9.11 its existence and importance
must nevertheless be recognised.
It should be emphasised that a modelling and simulation project of even modest size is often
carried out by a team of professionals where each member of the team typically contributes

154 LOVELY PROFESSIONAL UNIVERSITY