Civil Engineering Reference
In-Depth Information
increases physiological arousal and stress, thereby affecting task performance, safety, and
satisfaction.
The importance of the
organizational environment
has been increasingly emphasized
during the last few years. This movement in ergonomics is referred to as
macroergonomics
(Hendrick, 1995; Hendrick, 2001). Work is undertaken in an
organizational context, which deeply affects the appropriateness of alternative design
measures. Company policies with respect to communication patterns, decentralization of
responsibilities, and task allocation have an impact on ergonomics design. One should
first decide who should do what and how people should communicate. Following this
activity, individual tasks, machines, displays, and controls can be designed.
Macroergonomics is a much neglected area, and until recently there had not been
considerable research. One exception is the socio-technical research developed in the
U.K. in the 1950s (e.g., the Tavistock group). Perhaps because human factors research in
the military setting was quite dominant in the U.S., the importance of organizational
context was not emphasized.
Organizational considerations are important in the work context, but are less important
for design of leisure systems and consumer products. These are typically used by
individuals who do not have to consider collaboration and task delegation.
The
Machine
sub-system is broadly conceptualized in Figure 1.3. The term “machine”
is in a sense misleading. Here it stands for any controlled artifact. The “machine” could
be a computer, a video cassette recorder (VCR), or a football. The term
controls
denotes
machine controls that are used by the operator. Note that in some systems, machine
control may be taken over fully or partially by automation and computers.
As a result of machine control, there is a changing state which is displayed. It can be
seen or heard: a pocket calculator will show the results of a calculation; the melting iron
in a steel plant will change temperature and color; a computer will produce a sound: or a
toaster will pop up the bread. All of these are examples of displays. They convey visual
or auditory information, and they can be designed to optimize systems performance.
Streitz (2004) presented several examples of human-artifact interaction where displays
need not be necessarily CRT displays but can be artifacts, such as toast.
It is important to note that the system in Figure 1.3 has
feedback
. Machine information
is fed back to the environment subsystem and becomes integrated with the task.
Ergonomics is concerned with
dynamic systems
—it is necessary to go around the loop
and incorporate the effect of feedback. Ergonomics, in this sense, is different from other
disciplines. In experimental psychology, for example, there is no requirement for
studying dynamic systems.
With the system as a basis, we will now discuss three major systems goals in HFE that
were mentioned in the definition above: safety, productivity, and operator satisfaction.
1.6
THE GOAL OF SAFETY
Ergonomics is rarely a goal in itself. Safety, operator satisfaction, and productivity are
common goals. Ergonomics is a design methodology that is used to arrive at safety,
productivity, and satisfaction.
