ECET 4550:
Alternate Energy
Fall 2011
Laboratory Topic:
The Problem to be Solved
“Statement of the Problem”
Florian Misoc, 2010
Chapter Objectives
• Identifying and Representing the Client’s
Objectives
• Measurable Quantities
• Setting Priorities
• Constrains: Limitations and Delimitations
• Case Study and Examples
Florian Misoc, 2010
Introduction
• Problem Definition = the most important step in
the design process
• Problem Definition: pre-design phase of design
• Frame the problem => engineering terms
• Focus on tasks 1 – 4:
1. Clarify Objectives
2. Establish Metrics for Objectives
3. Identify Constrains
4. Revise Client’s Problem Statement
Florian Misoc, 2010
Identifying and Representing the Client’s
Objectives
• Client’s original problem statement:
a. Initial statements: brief, general idea
b. No hint on: intended market, shape of the
product, material to be used, etc.
c. Initial statement has limitations: errors, bias,
imply solutions
d. Clarify what client wants: what potential users
need,
e. Technological & marketing context
Florian Misoc, 2010
Identifying and Representing the Client’s
Objectives
1. Errors: incorrect information, faulty and/or
incomplete data, mistakes regarding the
problem
2. Biases: presumptions about the situation,
involving a person’s preference
3. Implied Solution: client’s best guess at
solutions, frequently found in the original
problem statement (related to bias)
Florian Misoc, 2010
Errors of the Design Process
Source: http://softwareindustrialization/CategoryView,category,Design.aspx
Errors of the Design Process
Source: http://softwareindustrialization/CategoryView,category,Design.aspx
Errors of the Design Process
Source: http://softwareindustrialization/CategoryView,category,Design.aspx
Errors of the Design Process
Source: http://softwareindustrialization/CategoryView,category,Design.aspx
Identifying and Representing the Client’s
Objectives: Questions & Brainstorming
Two kinds of activity:
a. Asking questions of the client/stakeholder, with
varying degree of interest in the problem/design
b. Brainstorming: group effort to generate,
retain, and organize new ideas to solve the
problem
Florian Misoc, 2010
Identifying and Representing the Client’s
Objectives: Asking Questions
Questions to understand the scope of the project:
a. What features/attributes you desire for …..?
b. What do you want this …. to do?
c. Are there already …. with similar attributes?
Ask also:
i. What does it mean?
ii. How are you going to do that?
iii. Why do you want that?
Florian Misoc, 2010
Identifying and Representing the Client’s
Objectives: Brainstorming
1. Focus on quantity: maxim quantity = quality.
Great number of ideas = greater the chance of
effective solution.
2. Withhold criticism: focus on extending or
adding to ideas, reserve criticism for a later
'critical stage' of the process
3. Welcome unusual ideas: looking from new
perspectives and suspending assumptions
(may provide better solutions)
4. Combine and improve ideas: Good ideas =
combinations of ideas: slogan "1+1=3”
Florian Misoc, 2010
Brainstorming: preliminary / start-up
Florian Misoc, 2010
Florian Misoc, 2010
Identifying and Representing the Client’s
Objectives: Concept Definitions
A. Objective: something toward which effort is
directed (an aim/end-of-action)
B. Constraint: restricted, compelled to avoid,
compelled to perform
C. Function: fitness for use, “for which a thing is
made-for”
D. Means: method used to attain and end
Florian Misoc, 2010
Client’s Objectives: Objective Tree
Florian Misoc, 2010
Measurable Quantities
Six Scale Types:
1. Nominal Scales: distinguish among categories
2. Partially Ordered Scales: hierarchies
3. Ordinal Scales: rank / order
4. Ratio Scales: percentage
5. Interval Scales: reference to a base-point
6. Multidimensional Scale: compounds of other
scales
Florian Misoc, 2010
Pair-wise Comparison Chart (PCC)
Should be applied in constrained “top-down”
fashion:
1) Objectives are compared when at the same
level (in the objective tree)
2) Higher level objectives: compared first
• Only “top objectives” need to be ranked
• “Low level objectives” are ranked ONLY for
complex systems
Florian Misoc, 2010
Weighted Objectives: American Beverage
Company
Goals
Environ.
Benign
Distribute
Taste
Parent
appeal
****
0
0
0
Distribute
1
****
1
Taste
1
0
Parent
Appeal
1
Market
Brand
Environ.
Benign
Brand
Score
0
0
0
1
1
0
4
****
0
0
0
1
0
1
****
0
0
2
1
0
1
1
****
0
3
1
1
1
1
1
****
5
Florian Misoc, 2010
Market
Weighted Objectives: National Beverage
Company
Goals
Environ.
Benign
Distribute
Taste
Parent
appeal
****
1
1
1
Distribute
0
****
0
Taste
0
1
Parent
Appeal
0
Market
Brand
Environ.
Benign
Brand
Score
1
1
5
0
1
0
1
****
1
1
1
4
1
0
****
1
1
3
0
0
0
0
****
0
0
0
1
0
0
1
****
2
Florian Misoc, 2010
Market
Pair-wise Comparison Chart (PCC)
• Pair-wise comparison chart for the “ladder
design”
Goals
Cost
Cost
Portability Convenience Durability Score
****
0
0
1
1
Portability
1
****
1
1
3
Convenience
1
0
****
1
2
Durability
0
0
0
****
0
Florian Misoc, 2010
Measuring Achievement of Objectives
• VDI 2225: Verband Deutscher Ingenieure /
Association of German Engineers
• No Mathematical foundation for scaling or
normalizing the PCC ranking
• PCC ranking = subjective preferences
• Never weigh objectives: it could amplify the error
(no mathematical foundation)
Florian Misoc, 2010
Scale of Awarding Points
Use-Value-Analysis
VDI-2225
Solution Value
Points
Perceived Value
Points
Absolutely useless
Very inadequate
0
1
Unsatisfactory
0
Weak
Tolerable
2
3
Just tolerable
1
Adequate
Satisfactory
4
5
Adequate
2
Good w. drawbacks
Good
6
7
Good
3
Very good
Exceeds requirements
Excellent
8
9
10
Very good / Ideal
4
Florian Misoc, 2010
Metrics for Objectives
• Metric = repeatable: conducting the
test/experiment (under identical conditions &
restrains) would lead to identical
results/outcomes
• Metric outcomes: understandable units of
measure
• Metric assessment: unambiguous
interpretation
Florian Misoc, 2010
Setting Priorities
“Lack of planning from your part does not
translate in a priority from my part…”
Priority level: determined in the same fashion
as awarding points
Priority # 1: SAFETY!!!
(read the “oath of the engineer”)
Florian Misoc, 2010
Constrains: Limitations and Delimitations
• Limitations: are imposed by the available
equipment, environmental conditions, time
constrains, etc., and are out of
experimenter’s control
• Delimitations: are imposed by the
experimenter, as to restrict the purpose of
said research
Florian Misoc, 2010
Case Study and Examples
Read and summarize:
1. Example 3.4.2: Establishing metrics for the
beverage container
2. Example 3.6.1: Objectives and Constrains for
the “Danbury Arm Support”
3. Example 3.6.2: Metrics for the Objectives
“Danbury Arm Support”
Due: same time as assignment of Chapter 3
Florian Misoc, 2010
Assignment:
•
•
•
•
Exercise # 3.1, page 77
Exercise # 3.2, page 77 & 78
Exercise # 3.5, page 78
Exercise 3.6, page 78: as it applies to your
particular group project
Florian Misoc, 2010