clarifying objectives
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8/3/2019 Clarifying Objectives
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Design Process Overview What drives design?
Design process has seven distinct phases
The end goal
Product that customers WANT
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Clarifying objectives: Objectives tree
Aim: to clarify design objectives
and sub-objectives, and therelationships between them.
Establishing functions : Function analysis
Aim: to establish the functions
required, and the systemboundary, of a new design.
Setting requirements : Performance specification
Aim: to make an accurate
specification of the performance
required of a design solution.
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Determining : Quality function deployment
characteristics Aim: to set targets to be
achieved for the engineering
characteristics of a product, such
that they satisfy customer
requirements.
Generating alternatives : Morphological chart Aim : to generate the complete
range of alternative design
solutions for a product, and hence
to widen search for potential newsolution
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Evaluating : Weighted objectives
alternatives Aim: to compare the utility values
of alternative design proposals,
on the basis of performance against
differentially weighted objectives.
Improving details : Value engineering
Aim: to increase or maintain the value of a product to its purchaser
while reducing its cost to its
producer.
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Clarifying objectives
The starting point for a design is therefore very often an ill-defined problem.
Yet the designer must have some objectives to worktowards.
The outcome of designing is a proposal for some means toachieve a desired end. That end is the set of objectives thatthe designed object must meet.
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What’s the Objective?
Objectives (or goals) are expressions of the desiredattributes and behaviors that the client wants to see in theproduct
Objectives are
‘Be’ words
They are qualities the object should have
So, designers task is to uncover the objectives of a designproject
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An important first step in designing therefore is to try to
clarify the design objectives.
Objectives may change, expand , contract or be completely altered as problem becomes better understood and as
solution ideas develop.
Objective statements are in such a form that they are easily understood by design team
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The Objectives Tree Method offers a clear and useful format for such a statement of
objectives. shows the objectives and the general means.
diagrammatic form.
How objectives are related to each other.
hierarchical pattern of objectives and sub-objectives.
Make vague statements more specific by asking: What is meant by that statement?
Other useful questions to ask when expanding andclarifying design objectives: Why? How? What?
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Objectives Tree Method (2)
Three step procedure:
Prepare a list of design objectives
Order the list into sets of higher-level and lower-level objectives
Draw a tree of objectives, showing hierarchicalrelationships and interconnections
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Step 1: Listing the Objectives This can be done by:
Talking with (interviewing) your customer
Thoroughly reading any written design statements andrequirements
Brainstorming within your team
Take vague statements and make them clearer by asking“what is meant by this statement”
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After the initial list is compiled, some things other thanobjectives may have slipped in
Constraints - restrictions or limitations on a behavior orsome aspect of a design
Functions - operations the design is supposed to do
Implementations - ways to execute the functions
Check if each statement is an objective Objectives are normally “being” statements
Try saying “an objective is to be [statement] ”
If it makes sense, then it’s most likely an objective
Objectives can also be written as “more (or less) of [thestatement] is better than less (or more) of [thestatement]”
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Step 1 Active Experimentation
An objective for a m/c tool that it must be safe, might beexpanded to
low risk of injury to operator
low risk of operator mistakes
low risk of damage to work-piece or tool
automatic cut-out on overload
'why do we want to achieve this objective?','how can we achieve it'?.' and 'what implicit objectivesunderlie the stated ones?' or 'what is the problem really about?'
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Step 2: Ordering the List
Group the statements into related topics using anaffinity diagram
Design
Objective
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Copy design objectives to post-it® notes
Place one on a board
Compare next objective card to the first
If different, begin a new column
If similar intent, place under the first column
Repeat for all design objective cards
Result: Objectives sorted by similar statement
Within each column there may be levels of objectives
Lower-level objectives answer the question “How?”
Higher-level objectives answer the question “Why?”
Transform to a hierarchical list of objectives
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Example:
SAFETY
machine must be safe
low risk of injury to operator
low risk of operator mistakes
low risk of damage to work-piece or tool
automatic cut-out on overload
'low risk of injury' might be considered more
important than 'low risk of mistakes', but allthree low risk objectives can conveniently
be grouped at about the same level.
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The valuable aspect to sorting objectives roughly intolevels is that it encourages you to think more clearly about the objectives and about the relationshipsbetween means and ends. As you write out your lists inhierarchical levels, you will probably also continue toexpand them, as you think of further means to meetsub objectives to meet objectives, etc.
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Step 3: Draw the Tree
From Step 2, you have a clustered set of objectives Notice that some of the objectives within a cluster
may be more specific than others
This implies a hierarchical nature to the objectives
The hierarchy (general to more specific) can berepresented in a graphical structure known as anobjectives tree
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Step 3: Draw the Tree (2)
Consider the example objectives list and resulting treefor the design of a safe ladder:
The ladder should be safe
The ladder should be stable
Stable on floors and smooth surfaces
Stable on relatively level ground
The ladder should be reasonably stiff
The ladder should be marketable
The ladder should be useful
Useful indoors
Useful for electrical work
Useful for maintenance work
Useful outdoors
Be useful at the right height
The ladder should be relatively inexpensive
The ladder should be portable
Be light weight
Be small when ready for transport
The ladder should be durable
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Step 3: Draw the Tree (3)
The Objectives Tree diagram looks like an “upside-down” tree The overall objective of the tree is at the top
Underneath it, branches break the objective intomore detailed objectives
Can have many levels and interconnections
As you move deeper into the
hierarchy, the objectives answer
the question “how is the above
objective met?”
As you move higher up in the
hierarchy, the objectives answer
the question “why are the below
objectives important?”
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Step 3: Draw the Tree (4)
The objectives treediagram may alternatively bedrawn on its side
Example: Car door
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Summary :
1. Prepare a list of design objectives. These are taken fromthe design brief, from questions to the client, and fromdiscussion in the design team.
2. Order the list into sets of higher-level and lower-level
objectives. The expanded list of objectives and subobjectives is grouped roughly into hierarchical levels.
3. Draw a diagrammatic tree of objectives, showinghierarchical relationships and interconnections. The
branches in the tree represent relationships whichsuggest means of achieving objectives.