Clarifying Objectives

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  • 8/3/2019 Clarifying Objectives


    Design Process OverviewWhat drives design?

    Design process has seven distinct phases

    The end goal

    Product that customers WANT

  • 8/3/2019 Clarifying Objectives


    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


    Generating alternatives : Morphological chartAim : 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 thevalue of a product to its purchaser

    while reducing its cost to its


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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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    Whats 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 completelyaltered as problem becomes better understood and as

    solution ideas develop.

    Objective statements are in such a form that they are easilyunderstood 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 ofhigher-level and lower-levelobjectives

    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 askingwhat is meantby 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 its 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 reallyabout?'

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    Step 2: Ordering the List

    Group the statements into related topics using anaffinity diagram



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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 hierarchicallist of objectives

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    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 clearlyabout 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 mayalternatively 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.