1. The Engineering Method Lecture 3

2. 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

3. “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.

4. 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

5. 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?

6. 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?

7. 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

8. Change time Measure of Change A B

9. 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!)

10. 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.

11. The Final State (B) Cannot Be Fully Known!

13. 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

14. 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.

15. 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.

16. 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

17. 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.

18. Television Example: Best Assuming Picture and Sound are Equally Weighted

19. Television Example: Best With Picture is half as important as Sound (for a person with hearing problems)

20. 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?

21. References Koen, Billy Vaughn, Discussion of The Method, Oxford University Press, 2003 Egypt map from CIA website: http://www.cia.gov/cia/publications/factbo ok/geos/eg.html\ Aswan Dam photo: http://upload.wikimedia.org/wikipedia/nl/th umb/f/fa/280px- AswanHighDam_Egypt.jpg