concept evaluation and selection 1230456811987317 2

7/31/2019 Concept Evaluation and Selection 1230456811987317 2

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Concept Evaluation andSelection

Prepared by: Weam Obaidat

Supervised by: Dr. Abdullah Dwairi


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Introduction

Concept Evaluation implies both comparison anddecision making.

The Goal : To expend the least amount of resources

on deciding which concepts have the highestpotential for becoming a quality product.

The Difficulty: To choose the best concept withvery limited knowledge and data on which to basethis selection.

Design is learning, and resources are limited

The greaterknowledge about the concept, the fewersurprises


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Introduction-cont.

Two Types of Comparisons Absolute: Alternative concept is compared

directly with a target set by a criterion

Relative:Alternatives are compared with eachother using measures defined by the criteria.

Possible only when there is more than one option.

For comparisons, the alternatives and criteria

must be: In the same language(meters vs. long)

At the same level ofabstraction


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Concept Evaluation Techniques

There are many techniques used to evaluate

concept such as:

o

Feasibility Judgmento GO/NO-GO Screening

o Basic Decision Matrix

o Weighted Decision Matrixo Advanced Decision Matrix

o Analytical Hierarchy Process (AHP)


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Concept Evaluation Techniques


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Evaluation based on Feasibility

Judgment Three Immediate Reactions of a Designer

as a concept is generated based ondesigners gut feel:

It is not Feasible. It might work if something else happens.

It is worth considering.

A comparison based on experience andknowledge


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Judgment

Implications of Each of these Reactions:It Is Not Feasible

Before discarding an idea, ask Why is it notfeasible?

- Technologically infeasible

- Not meeting customers requirements

- Concept is different

- NIH Make sure not to discard an idea because:

a concept is similar to ones that are already established,or

a concept is not invented here (less ego-satisfying).


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Judgment It is Conditional.

To judge a concept workable if something else

happens. Factors are the readiness of technology, the

possibility of obtaining currently unavailable

information, or the development of some

other part of the product.


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JudgmentIt is Worth Considering

The hardest concept to evaluate is one that is not

obviously a good idea or a bad one, but looks

worth considering.

Such a concept requires engineering knowledge

and experience. If sufficient knowledge is not

immediately available, it must be developedusing models or prototypes that are easily

evaluated.


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Evaluation based on GO/NO-GOScreening

Measures for deciding to go or no-go:

1 Criteria defined by the customerrequirements:

Absolute evaluation by comparing eachalternative concept with the customerrequirements.

A concept with a few no-go responses may be

worth modifying rather than eliminating This type of evaluation not only weeds outdesigns that should not be considered further,but also helps generates new ideas.


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2 Readiness of the technologies used:

This technique refines the evaluation by forcingan absolute comparison with state-of-the-art

capabilities.

The Technology must be mature enough that its

use is a design issue, not a research issue.

There are high incentive to include newtechnologies in products.


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6Measures for a Technologys Maturity:

Are the critical parameters that control the functionidentified?

Are the safe operating latitude and sensitivity of theparameters known?

Have the failure modes been identified?

Can the technology be manufactured with knownprocess?

Does hardware exist that demonstrates positive answers

to the preceding four questions?Is the technology controllable through the products lifecycle?

If these questions are not answered in the positive, aconsultant or vendor is added to the team.


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Evaluation based on a BasicDecision Matrix

Decision-Matrix Method (or Pughs Method):

1. Select decision criteria

2. Formulate decision matrix

3. Clarify design concepts being evaluated

4. Choose Datum or best initial concept

5. Compare other concepts to Datum based on +, -, S scale.6. Evaluate the ratings: important to discuss concepts strengths

and weaknesses. Good discussion can lead to new,combined, better solution concepts

7. Select a new datum concept and rerun analysis

8. Plan further work. Often new needs for information andconcepts come from first meeting.

9. Second working session to repeat above and select aconcept.


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Con.5Con. 4Con. 3Con. 2Con. 1Importance

Criterion

D

A

TU

M

S-S-S25Manufacturing Cost

+SSS+15Easier Opening

-+-SS9Easier to remove leaflet

S+++S15Easier to remove CD

+SSS+10Hinge doesnt comeapart

+SSSS9Stacking stability

+++S+10More secure locking

+S++S7Fits hand better

53323Total +

11110Total -

42213Overall total

42923-335Weighted total


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Evaluation based on a Basic

Decision Matrix

Notes from above example:

Value of S = 0 Overall Total for concept 3= no. of (+) - no. of (-)

= 3-1=2

Weight Total for concept 2= 25*(-1) + 15*0 + 9*0

+15*1 + 10*0 + 9*0 + 10*0 + 7*1 = -3

From above table Concept 5 is the best


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Evaluation based on a Weighted

Decision Matrix

Develop a criteria weighting matrix

Select interval scale for evaluation scoring

Create weighted decision matrix and sum weighted

evaluations. Select highest value

Consider combining strengths of various concepts

and rerunning with new concepts


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Decision Matrix


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Decision Matrix


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Evaluation based on a WeightedDecision Matrix


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Robust Decision Making

Robust decisionrefers to make decisions that are asinsensitive as possible to the uncertainty, incompleteness,and evolution of the information that they are based on.

For robust decision making, we need to improve the method

used to evaluate the alternatives (step 4 in decision-matrixmethod).

Word Equations used for Robust Decision Making

Satisfaction = belief that an alternative meets the criteriaBelief = knowledge + confidence Belief is the confidence placed on an alternatives ability to

meet a target set by a criterion, requirement, or specification,based on current knowledge.

Belief (virtual sum of knowledge and confidence) can beexpressed on a Belief map.


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Belief Map


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Belief Map-Cont.


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Belief Map-Cont.

Belief=1

Belief=.5 Belief=.5

Belief=0


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Evaluation based on Advanced

Decision Matrix

Steps 1 through 3: same as the Decision Matrix

Method

Step 4: Evaluate Alternatives Use a belief map for comparison

If little is known or the evaluation result is that

the alternative possibly meets the criterion, then

belief = 0.5 Step 5: Compute Satisfaction

Satisfaction = S (belief x importance weighting)

Max satisfaction = 100 (evaluator is 100%

satisfied.)


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Evaluation based on AdvancedDecision Matrix

E l ti b d A l ti


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Evaluation based on AnalyticHierarchy Process

Use Saatys fundamental scale for pairwise

comparison

Determine weighting factors on criteria

Determine ratings for each concept relative to eachfactor by fractional quantitative or qualitative

ranking or pairwise comparison between concepts

for each criteria.

Create decision matrix Highest weighted sum is selected.

Software: Expert Choice

Evaluation based on Analytic


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Hierarchy Process


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Hierarchy Process


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Hierarchy Process


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Evaluation based on AnalyticHierarchy Process

Decision Management Method


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Decision Management MethodSelection Logic


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Information Presentation in ConceptEvaluation

There are two ways to present the information in

Concept evaluation:

o Design-build-test cycle: building physical models or

prototypes.- ForNew technology orcomplex known technology

o Design-test-build cycle: developing analyticalmodels and simulating (i.e., testing) the concept before

any thing built.- For systems that are understood and can be modeled

mathematically.

Information Presentation in Concept


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Information Presentation in Concept

Evaluation

Design-build-test cycle

Design-test-build cycle

concept evaluation and selection 1230456811987317 2

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