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

September 2003 Chuck DiMarzio, Northeastern University 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

September 2003 Chuck DiMarzio, Northeastern University 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

September 2003 Chuck DiMarzio, Northeastern University Some Examples (1) Phone Numbers –“Sally, get me Mary,” 1507M, SU –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?

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

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

September 2003 Chuck DiMarzio, Northeastern University 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)

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

September 2003 Chuck DiMarzio, Northeastern University 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

September 2003 Chuck DiMarzio, Northeastern University 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

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

September 2003 Chuck DiMarzio, Northeastern University 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

September 2003 Chuck DiMarzio, Northeastern University Lighting Efficiency 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 com. 10 June Lumens/Watt for Green Light Power Input, Watts