September 2003 Chuck DiMarzio, Northeastern University 10379-4-1

The Design Process: Problem Formulation

Charles A. DiMarzio

GEU110

Northeastern University

September 2003 Chuck DiMarzio, Northeastern University 10379-4-2

The Design Process

NeedsAssessment

ProblemFormulation

Abstractionand Synthesis

Analysis

Implementation Ch. 2

3, 4, 5

6,7

8,9,10

11

• Remember these phases are not absolute

• The edges are rough• We often use multiple

loops• Usually we don’t think

about the process at all• It’s best taught by

examples

September 2003 Chuck DiMarzio, Northeastern University 10379-4-3

What is the Real Problem?

• Constraints and Boundaries (quantitative)– Maximum size hole in aircraft for Lidar

• Qualitative Goals (“more” or “less”)

• Restate Goal, Change Emphasis

• Input/Output Analysis

• ???

September 2003 Chuck DiMarzio, Northeastern University 10379-4-4

Revision Method

• Method– Start with something that works,– Build it,– Refine it through evolutionary design.

• Advantages– Working design in short time– It just might be good enough– It points out the approach to making it better

• Example– Mohs Surgery

September 2003 Chuck DiMarzio, Northeastern University 10379-4-5

Duncker Diagram

Present State Desired State

General Solutions

Functional Solutions

Specific Solutions

System Level Problems; Environment, Transportation

September 2003 Chuck DiMarzio, Northeastern University 10379-4-6

Kepner-Tregoe Situation Analysis

Timing (urgency)

Trend (growth)

Impact (consequences)

September 2003 Chuck DiMarzio, Northeastern University 10379-4-7

Kepner-Tregoe Problem Analysis

Identity

Location

Timing

Magnitude

WhatIs?

WhatIs Not?

DistinctionCause ofDistinction

September 2003 Chuck DiMarzio, Northeastern University 10379-4-8

Kepner-Tregoe Problem AnalysisWhat is? What is not? Distinction? Possible

Cause?

Coming Later…

K-T Decision Analysis

(Quantitative)

September 2003 Chuck DiMarzio, Northeastern University 10379-4-9

What is the Value of These Methods?

• Thinking (Alone)

• Brainstorming (Together)

• Justifying (to whom?)Think about formal vs. Informal useof these Methods.

September 2003 Chuck DiMarzio, Northeastern University 10379-4-10

An Example

• Severe Storms Lidar Scanner to produce a stable scan pattern from an aircraft with roll, pitch (and heading?).

• 13” hole in airplane

• Airworthyness issues for outside structures

• Cost, speed (1/4 sec), etc.

September 2003 Chuck DiMarzio, Northeastern University 10379-4-11

Example Continued

• Proposal Brainstorming– Stick Model for Light Beams– 2 Mirrors, Gimbled Mirror, Flip Mirror– Outside Structure, Wedge, 2 Wedges

• Abstraction, Synthesis, Analysis for Each• Implementation only for 2 Wedges

– Then developed more complicated model with calibration

September 2003 Chuck DiMarzio, Northeastern University 10379-4-12

Major Project Guidelines

• What are you proposing?– One of a kind (eg. Bridge)– One at a time (eg. femtosecond laser)– Mass production (eg. Consumer product)

• Prototype (think about design and single-unit cost)

• Production line (think about cost per unit)

September 2003 Chuck DiMarzio, Northeastern University 10379-4-13

Some Major Project Issues

• Why is your design needed?• What problem are you trying to solve?• Why is your solution best?• What analysis will you do?• Who can/will pay the required cost?• What are the unintended consequences?• What are the political and social issues?• What are the environmental issues?• What expertise do you need on your team?

NeedsAssessment

ProblemFormulation

Abstractionand Synthesis

Analysis

Implementation Ch. 2

3, 4, 5

6,7

8,9,10

11

September 2003 Chuck DiMarzio, Northeastern University 10379-4-14

Minor Project

• Grading on– Report (40%)– Device (40%)– Success (20%)

September 2003 Chuck DiMarzio, Northeastern University 10379-4-15

A Word About Reports

• I give points for– Cover Letter (If appropriate)– Abstract– Table of Contents and Figures– Technical Content (Most heavily)– References (If appropriate)– Grammar and Spelling– General Appearance

September 2003 Chuck DiMarzio, Northeastern University 10379-4-16

Some Grammar Issues

• A preposition is a terrible part of speech to end a sentence with.

• And starting with a conjunction isn’t much better.

• Another thing. Little short phrases. Not quite sentences. Not good. Unless you are Jonathan Franzen.

September 2003 Chuck DiMarzio, Northeastern University 10379-4-17

Some Style Issues• Use section headings.• Informal expressions in technical writing are

usually uncool.• Use parallel constructions in lists.

– Never have one item in a sublist

• Active voice and first person are acceptable to me, but not to everyone in engineering.– “Mistakes were made.”– You shouldn’t use the second person.

• Give figures and tables numbers, and refer to them in the text.

September 2003 Chuck DiMarzio, Northeastern University 10379-4-18

Websites as Sources

• Use the web to...– Learn about a new field

– Find out who is working in the field

– Get pointers to the archival literature

• Do not use web pages as citations– They are transient

– They are not refereed

– Catalog information for pricing, etc. is an exception if you include date information, etc.

September 2003 Chuck DiMarzio, Northeastern University 10379-4-19

Some Ethical Issues

• If you borrow a figure, cite the source.

• Reference anyone who contributes to your idea.

• Paraphrasing is not the same thing as expressing your own thoughts.

September 2003 Chuck DiMarzio, Northeastern University 10379-4-20

Teams

• 1: Rishi Dhupar, Bryan Mayor, Joe Mayotte

• 2: Matt Bouchard, Brian Carlin, Anne Fitzpatrick

• 3: Eric Blaisdell, David Despres, Mikio Yanagisawa

• 4: Chuba Arah, Marco Solia, Jonathan Palmer

• 5: Shannon Rooney, Jenine Davignon, Kevin Harvey

• 6: Sean O'Blenis, Kelly Chronley, Sammy Shaar

• 7: Graham Turner, Danny MacDougall, Steve Jahnes

• 8: Dan Bastable, Bryan Fors, Kyle Nowak

• 9: Jonathan Correia, Marsel Kane, Khue Nguyen, Steve Yu

• 10: Michael Hart, Mike Santorella, Robert Taylor