The Engineering Method

Lecture 3

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

Why is Engineering Such a Mystery?

• The Engineering Method– Little significant research into the

philosophical foundations of engineering.– Can you name an engineer who is wise, well-

known, well-read, and scholarly in their role as an engineer?

• Contrast with law, economics, medicine, politics, religion, and science– Can you name a public spokesperson in any

of these fields?

Why is Engineering Such a Mystery?

• Few high school students take engineering courses

• Liberal arts students are not required to study technology– What about vice versa? Especially here?

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

Change

time

Mea

sure

of C

hang

e

A

B

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 drifts!)

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• 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

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 correct from an engineering point of view because it was done within the time constraints imposed.

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)

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?

References

• Koen, Billy Vaughn, Discussion of The Method, Oxford University Press, 2003

• Egypt map from CIA website: http://www.cia.gov/cia/publications/factbook/geos/eg.html\

• Aswan Dam photo: http://upload.wikimedia.org/wikipedia/nl/thumb/f/fa/280px-AswanHighDam_Egypt.jpg