FACTOR OF SAFETY
Factor of safety states that the use of extra elements in a design that
is thought to be necessary in order to prevent system failure and minimize the
effect of unknown variable. An extra element can be added into a design to
improve its factor of safety.
The picture shows a distribution board from my home at Academia Lane,
Kota Samarahan. The distribution board will protect the circuits and electrical
equipment at home. The distribution board will divide an electrical power into
subsidiary circuits by providing a protective fuse for each circuit. When there
is an overload or there is a fault in the circuit, the fuse will blow and the
current will be cut off to that circuit. This can prevent serious electric
shock if there is an electrical fault.
FLEXIBILITY USABILITY TRADE
OFF
Flexibility
usability-tradeoff principle states that as the flexibility of a design
improve, the usability will decrease. A design is designed to have more
functions to make the design more flexible. However, it will also make the
design to be more complex. Therefore, it will make the usability of the design
will decrease.
The picture above shows a fax machine with phone. This fax machine is
flexible because it can be used to fax papers and it also has a landline where
users can use it as normal house phone also. However, due to this flexibility,
it will also make this phone more complex and more difficult to use compared to
normal house phone because of its multiple function. Thus, the usability of
this phone will decrease.
Redundancy states that the use of more elements in order to maintain the
performance of a system when there is a failure of one or more element.
a)
Diverse
redundancy – the use of multiple elements of different types and is resistant
to a single cause of failure. However, it is difficult to use and maintain.
when you forgot your password, you can still log in using your phone number or fullname.
b)
Homogenous
redundancy – the use of multiple elements of the same type which is simple to
use and maintain. However, it is susceptible to a single cause of failure.
The pictures show the door with two locks of the same
type. Both the locks are used to prevent thieves or burglars from breaking in. The
lower lock act as the secondary lock if thieves are able to broke the window
beside the upper lock. However, if the lower lock is spoilt, then it will lead
to failure in preventing the happening of breaking in.
c)
Active
redundancy – the application of redundant elements of all time. This means that
this element is always active.
The pictures show the door and the door hinge. The
hinges aid in opening and closing of the door and also to connect the door and
the wall all the time. The hinges can make sure the door will not fall as it
holds the door.
d)
Passive
redundancy – the application of redundant elements when an active element
fails. This element is triggered or activated when there is a failure in the
active element.
The pictures above show the picture of a blouse and
the extra button attached with it. If one of the buttons on the blouse is
spoilt of missing, then the extra button can be used to replace it.
OCKHAM'S RAZOR
Ockham’s razor principle states that when there is a
choice given to choose between designs with equal functionality, a more simple
design is tend to be chosen. In order to avoid confusion, simple design is more
likely to be selected.
The pictures show the electric toothbrush on the left and a normal
toothbrush on the right. Both the toothbrushes have equal function which is
used to brush teeth. Where there is an equal in terms of function, product with
simpler design is tend to be chosen. Therefore, the normal toothbrush on the
right tends to be chosen.
SATISFICING
Satisficing states that it is often preferable to choose a satisfactory
solution instead of an optimal solution.
The pictures above show two screwdriver set. The screwdriver set on the
left tend to be chosen because it is a more satisfy choice where it can fulfill
the basic needs of user while the screwdriver set on the right is a more
optimal design where it have more choices of different size and shape.
FORM FOLLOWS FUNCTION
Form follow function states that the beauty in a design is the results
from the purity of the function. The function of a product should be taken into
consideration before its outer form. A product should be able to perform its
function as usual despite the difference form of design.
The pictures show two different form of fruit or vegetable peeler. Despite
the difference in the design of the peelers, both are able to act the same
which is to peel the skin of the fruits or vegetables.