The Engineering Method
Based on “Discussion
of the Method” by Billy
Vaughn Koen
EGR 3380
Engineering Design I
What is an Engineer?
• An Engineer is not defined by her product
– Nano-robots
– Airplanes
– Embedded Computers
• An engineer is defined by her method
– Finding the best change
– Using available resources
– In an environment of uncertainty
“To Engineer”
• The clergy in Iran engineered the firing of
the president.
• The chessmaster engineered a perfect
countermove.
• The general engineered a coup d'état
without the loss of life.
Why is Engineering Such a
Mystery?
• The Scientific Method
– Well-understood, even by the layperson.
– “Science is theory corrected by experiment.”
– All variables held constant except one.
– “Answer in the back of the book.”
• Extensively analyzed by philosophers
• None of these are true for the
Engineering Method
– Although engineers often employ science
and scientific reasoning
Four Key Elements of
Engineering Problems:
• Change: the situation requires a
change.
• Best: the best change is desired...
• Resources: using the available
resources.
• Uncertainty: knowledge about the
situation is incomplete and sometimes
inconsistent
Four Key Elements of
Engineering Problems:
• Change: the situation requires a
change.
• Best: the best change is desired...
• Resources: using the available
resources.
• Uncertainty: knowledge about the
situation is incomplete and sometimes
inconsistent
Measure of Change
Change
A
B
time
Change
• Four practical difficulties in getting from A
to B:
– Engineer lacks complete knowledge of the
world at A
– The exact final state, B, is unknown and
cannot be anticipated
– There is no single path from A to B
– Engineering goals can change during the
process (the location of B floats!)
Change
• Is all change caused by engineers good?
– What about unintended consequences?
• Aswan High Dam in Egypt
• Can you name any others?
– Can you think of any engineering
disasters?
• Tacoma Narrows Bridge, WindBelt
• Kansas City Hyatt Regency
• Chernobyl Nuclear Power Plant in U.S.S.R.
The Final State (B) Cannot
Be Fully Known!
Unforeseen Consequences
• Increased salinity of the Nile by 10%
– Led to collapse of sardine industry
• Caused Coastal Erosion
• Displaced 100,000 Nubians
– Drastically altering their way of life
• BUT provides ½ of Egypt’s electrical
needs
Four Key Elements of
Engineering Problems:
• Change: the situation requires a
change.
• Best: the best change is desired...
• Resources: using the available
resources.
• Uncertainty: knowledge about the
situation is incomplete and sometimes
inconsistent
Best
• Best for whom?
– Westerners are conditioned to accept Plato’s
notion of the Ideal
– A new concept of “best”
• Optimization theory
– The Optimum compromise
– Apollo Program
• Leapfrog learning
• Political vs. Economic tradeoffs
Television Example: Best
Consider a television with only one knob:
Increased knob setting results in sharper
picture,
Increased knob setting also results in worse
sound.
Television Example: Best
Assuming Picture and Sound are Equally
Weighted
Television Example: Best
With Picture is half as important as Sound (for
a person with hearing problems)
Four Key Elements of
Engineering Problems:
• Change: the situation requires a
change.
• Best: the best change is desired...
• Resources: using the available
resources.
• Uncertainty: knowledge about the
situation is incomplete and sometimes
inconsistent
Available Resources
• Tangible Resources
– Money available for project
– Time to complete project
– Raw materials like steel, concrete, silicon
– Computer resources
– Number and education of engineers
• Intangible Resources
– Past experience with similar projects
– Engineer’s interests, passions, etc.
Time as a Resource
• Problem: estimate number of ping-pong
balls that can fill the room in
– 60 seconds
– 2 days
– Unlimited time
• Each time limit defines a new engineering
problem because the time resource is
different
• Each solution would be valid from an
engineering point of view because it was
done within the time constraints imposed.
Four Key Elements of
Engineering Problems:
• Change: the situation requires a
change.
• Best: the best change is desired...
• Resources: using the available
resources.
• Uncertainty: knowledge about the
situation is incomplete and sometimes
inconsistent
Uncertainty
• Engineers are asked to find a solution to
a problem while lacking complete
information
• In Change: both the starting and ending
points (A & B) are not fully known
• Resources: intangible resources cannot
be quantified, yet they affect the outcome
• Best: the best design is not always clear,
best for whom?
What is an Engineer?
• An Engineer is not defined by her product
– Electrical Engineer
– Computer Engineer
– Mechanical Engineer
• An engineer is defined by her method
– Finding the best change, using available
resources in an environment of uncertainty
• Engineering Degree great training for…
– Business, Medicine, Law, Politics, Development