Biomedical Engineering Reference
In-Depth Information
6.5 Selecting Concepts and Ideas
While the generation of ideas is, in the terms of cricket, a
free hit
1
, the selection of the most
appropriate idea is more formal and often more difficult. To this end I will present a few tools
that have stood the test of time.
6.5.1 Morphological Analysis
Table 6.4
illustrated the morphological table including all paths. However, it should be
apparent that at least one path would “fit the bill.”
Table 6.6
illustrates this for a device to
monitor the temperature of a patient, constantly.
The black arrows show a number of paths that could be taken. However, the optimal path is
highlighted in gray. In order to fulfill the audit trail the reasons for selecting this gray path
should be given. They may be quite subjective, as design choices often are, but they must
be written down. So, for example, the data transmission may have been either Bluetooth or
ZigBee, but ZigBee was chosen because more than one temperature probe can be monitored.
Or it could have been ZigBee because it would be the only thermometer on the market using
this technology. The best way to log these decisions is to annotate the diagram (if possible),
or to number the arrows and have a separate sheet with the arrow number and reasons for the
choice given (as illustrated in
Table 6.7
).
As you can see this table could be very verbose and, hence, hard to complete for very large
projects. The next option is a numeric-based system.
6.5.2 Criteria Assessment
You will have spent a lot of time developing a specification hence it makes sense to use it.
If you have discretized your project then you will have split and reformed the PDS too. This
Table 6.6: Example of Morphological Analysis to Select an Ideal Solution
Specification
Feature
Solution 1
Solution 2
Solution 3
Solution 4
Solution 5
Specifi cation
Feature
Solution 1
Solution 2
Solution 3
Solution 4
Solution 5
1
temperature
1. Measure
temperature
M
e
M
thermometer
Mercury
thermometer
y
I
Infrared camera
a
e
c
a
T
Thermocouple
T
Temperature
sensitive gels
a
e
I
circuit chip
Integrated
circuit chip
e
a
e
sensitive gels
2
2. Transmit
data
T
a
W
Wires
e
B
Bluetooth
ZigBee
Zigbee
R
Radio
I
Infrared
a
e
data
3
3. Collect data
C
d
a
P
PC
S
Smartphone
t
P
Pad
C
Chart plotter
t
p
e
4
4. Plot data
P
d
a
P
Printer
e
P
Plotter
e
S
Screen
e
C
Chart plot
t
p
1
A free hit occurs in some games of cricket to stop a bowler from constantly bowling illegal balls. If an illegal ball
is given then the next ball is a “free hit” and the batsman cannot be given out. Hence it is a relatively easy task!
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