EENG 1920 Chapter 4

Concept Generation and Evaluation

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Barriers to Creativity

• Perceptual block– Prevents you from seeing the problem– Put constraints on the problem that is not there– See a solution to a problem that one is biased to see

• Emotional block– Fear of failure– Fear of chaos and disorganization– Tendency to critically judge ideas

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Barriers to Creativity

• Cultural and Environmental Block– Things in our environment that limit creative ability– Team members distrust each other– Autocratic management resists new ideas

• Intellectual and Expressive Block– Need an understanding of engineering tools– Engineering tools are need that you do not have

• MATLAB• LABVIEW• VHDL• SPICE

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Vertical and Lateral Think

• Vertical thinking– Focuses on sequential steps toward a solution– Tries to determine correctness of the solution– Tries to narrow to a single solution

• Lateral thinking– Jumping around between steps– No attempt to determine right or wrong solutions– No attempt to narrow to a single solution narrow

to a single solution

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Strategies for Creativity

• Have a questioning attitude• Practice being creative• Suspend judgment• All incubation time• Think like a beginner

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SCAMPER(Guide to Generate Creative Concepts)

• Substitute

• Combine

• Adapt

• Modify

• Put to other use

• Eliminate

• Rearrange or Reverse

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Concept Generation• Search Externally– Literature review

– Search and review existing products

– Benchmark similar products

– Interview experts

• Search Internally– Brainstorming/brainwriting

– Nominal Group Technique

– Concept Table/Fans

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Brainstorming

Rules for group brainstorming• No evaluation or judgment of ideas permitted.• Encourage wild ideas.• Focus on quantity, not quality (can always toss later!)• Build upon, combine, or modify the ideas of others

(SCAMPER).• Record all ideas.

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Concept Table(Computer Design)

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User Interface Display Connectivity & Expansion

Power Size

Keyboard CRT Serial & parallel

Battery Hand-held, Fits in pocket

Touchpad Flat Panel USB AC Power Notebook size

Handwriting Recognition

Plasma Wireless Ethernet

Solar Power Wearable

Video Heads-up display

Wired Ethernet

Fuel Cell Credit card size

Voice LCD PCMCIA Thermal transfer

Flexible in shape

Modem / Telephone

Concept Fan

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RTD

Sensor

Thermo-couple

Therm-istor

WasherType

WireTube and

Wire

Temp toVoltage

Conversion

Op Amp

InvertingNon-

Inverting

Transistor

SingleTransis-

tor

CurrentMirror

Display

7Segment

LEDLCD

AnalogDial

LED BarLevel

Indicator

Design

Concept Evaluation

Decision Methods (some of them)

• Strength & Weakness Analysis

• Analytical Hierarchy Process (Decision Matrix)

• Pugh Concept Selection

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Strength & Weakness Analysis

• Identify and list strengths and weaknesses of each concept.

• To make more analytical, assign subjective weights to strengths and weaknesses (plus and minus factors) and sum them.

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Analytical Hierarchy Process (AHP)(Decision Matrix)

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Design Option 1

Design Option 2

Design Option n

Criteria 1

11 12 1n

Criteria 2

21 22 2n

Criteria m

m1 m2 mn

Score

Decision Matrix: Steps

• Step 1: Determine the selection criteria

• Step 2: Select the criteria weightings

• Step 3: Identify and rate alternatives relative to the criteria

• Step 4: Compute the scores

• Step 5: Review the decision14

Example: Quantitative Decision

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• Select a current source circuit for current measurement• RTD = Resistance Temperature Device

RTDRREF

VCC

+VT-

I

RTD

RE

-VEE

VCC

+VT-

I

V

+

-

RTD

R

+ VT -

I

Step 1: Select the Criteria

In this case they are given as• Accuracy• Cost• Size• Availability

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Step 2: Select the Weighting Factor

• These are computed based upon the results of the pairwise comparison – given in the problem.

• Be sure to normalize the final values.

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Step 3: Compute Design Ratings

They need to be computed for the following• Accuracy• Cost• Size• Availability

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Step 4: Compute the Scores

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Single BJT

Op Amp Current

MirrorAccuracy 0.4

2Cost 0.1

2Size 0.1

2Availabili

ty0.34

Score

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Pugh Concept Selection1. Select the comparison criteria2. Determine weights for the criteria3. Determine the concepts4. Select baseline concept, initially believed best 5. Compare other concepts to baseline: ◦ +1 better than, 0 equal to, -1 worse than.

6. Compute weighted score for concepts, not including the baseline.

7. Examine concepts: retain, update, or drop. Synthesize best elements of others where possible.

8. Update table & iterate until best concept emerges.

Pugh Concept Table

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Option 1

(Reference)

Option 2 Option 3

Option 4

Criteria 1

4 - 0 0 +1

Criteria 2

5 - +1 -1 0

Criteria 3

2 - -1 0 +1

Criteria 4

1 - +1 +1 -1

Score - 4 -4 5

Continue? Combine Yes No Combine

Project Application

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• Identify different design alternatives (see also Chapters 5 and 6).– Search externally– Brainstorming sessions.– Nominal Group Technique– Morphology (Concept Tables and Fans)– SCAMPER

• Identify leading concept and justify– Strength & Weaknesses Analysis– Decision Matrices– Pugh Concept Selection

Chapter 4 Homework

1. Name four barriers to creativity.2. What is vertical thinking?3. What is lateral thinking?4. What are the five steps of a decision matrix?

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