1. September 2003 Chuck DiMarzio, Northeastern University 10379-2-1 The Design Process: Needs Assessment Charles A. DiMarzio GEU110 Northeastern University

2. September 2003 Chuck DiMarzio, Northeastern University 10379-2-2 The Design Process Needs Assessment Problem Formulation Abstraction and Synthesis Analysis Implementation Ch. 2 3, 4, 5 6,7 8,9,10 11 First Step: Needs What Does This Mean? It’s Not So Easy! Examples: –Urban Transportation –Power Grid

3. September 2003 Chuck DiMarzio, Northeastern University 10379-2-3 Different Perspectives on Needs The Best Solution The Best from Where We Are The Best We Can Afford Good Enough Short- vs. Long- Term Planning –eg. Buried Waste Disposal

4. September 2003 Chuck DiMarzio, Northeastern University 10379-2-4 Some Examples (1) Phone Numbers –“Sally, get me Mary,” 1507M, SU7-7777 –7, 10 and 11 digit dialing –Why the area codes 212 = NYC, 213 = LA 312 = Chicago, 617 = BOS –What Next? –Just for Fun for Boston People What Were Exchange Names of 536, 262, 268?

5. September 2003 Chuck DiMarzio, Northeastern University 10379-2-5 Some Examples (2) FM Radio, FM Stereo Radio MOKE Current Sensor, Magnetometer IVHS Wake Vortex Avoidance Glucose Monitor The Video Store vs. The Net

6. September 2003 Chuck DiMarzio, Northeastern University 10379-2-6 FM Stereo Radio Transmitter 1 Transmitter 2 Receiver 1 Receiver 2 Left signal Right signal Left speaker Right speaker Why Not?

7. September 2003 Chuck DiMarzio, Northeastern University 10379-2-7 FM Stereo Radio Transmitter 1 Transmitter 2 Receiver 1 Receiver 2 Left signal Right signal Left speaker Right speaker How it really works: 4-Way Compatible L+R L-R (L+R)+ (L-R) (L+R)- (L-R) Why? (Carrier) (Sidebands)

8. September 2003 Chuck DiMarzio, Northeastern University 10379-2-8 Mono Transmitter TransmitterReceiver 1 Receiver 2 Left speaker Right speaker The Signal (L+0)+ (0) (L+0)- (0) (Carrier)

9. September 2003 Chuck DiMarzio, Northeastern University 10379-2-9 Mono Receiver Transmitter 1 Transmitter 2 Receiver 1 Left signal Right signal The speaker L+R L-R (Carrier) (Sidebands) Mono Transmitter and Receiver: An Exercise for the Interested Student

10. September 2003 Chuck DiMarzio, Northeastern University 10379-2-10 Other Perspectives Market Pull vs. Technology Push –A Key Question in the Research World Political Perspectives –Policy vs. Market Economic Perspectives –“Don’t Make it Too Cheap” Random Events

11. September 2003 Chuck DiMarzio, Northeastern University 10379-2-11 Brunelleschi’s Ox-Hoist Firenze, Summer 1420 What were the Needs? How does it work? Reference: –King, Ross, Brunelleschi’s Dome, Penguin, New York, 2001. Pg. 59.

12. September 2003 Chuck DiMarzio, Northeastern University 10379-2-12 Other Examples Color TV from Black and White –4-Way Compatibility and Bandwidth LED’s for Efficient Illumination –The Next New Thing??? –The Color Problem? –Low Voltage DC vs. Higher Voltage AC –See Next Page

13. September 2003 Chuck DiMarzio, Northeastern University 10379-2-13 Lighting Efficiency 100 1000 10000 100000 1000000 1101001000 10000 Light Output, Lumens Fluorescent Hi Pressure Na Metal Halide Lo Pressure Na Incandescent 94 Lumens/Watt at 7000K (Highest Efficiency) 20.7 Lumens/Watt at 3000K Thanks to John Hilliar (NU MS ECE 1999) for finding lighting data from Joseph F. Hetherington at www.hetherington. com. 10 June 1998 683 Lumens/Watt for Green Light Power Input, Watts