Rap 1

Value Proposition

a short, succinct statement that conveys how value will be created, captured, and sustained with the potential design-to-be

target design specifications

describe the essential and desired properties of a product before that product is even designed

Value Proposition, Identify Needs, Set specifications, Generate Concepts, Evaluate Concepts, Design in Detail, Build, (Review, Revise, Produce, Maintain, Recycle)

stages in the design process

• identify all the important needs and requirements for the design

• generate a greater number and variety of potential design solutions

• identify and correct for problems earlier, thereby minimizing the likelihood of major design revisions

• be able to support and communicate their design decisions to others using convincing justification

Why use the design process?

Function Decomposition

describe the design problem in terms of the functions- and sub-functions-that must be addressed

Concept Generation Methods

External Search, Internal Search, Logical Methods

Function Decomposition, Concept Generation, Concept Combination, Conceptual Solutions for Evaluation

Conceptual Design Process

Concept generation

identify possible solutions to each function

Concept combination

combine the concept fragments from the functions to form complete conceptual solutions to the entire problem

Function

description of something a device does without specifying or suggesting how the device achieves that action or outcome

Top Level Functions

a function that is present in every conceivable solution to a design problem

sub-function

a function present in only some solution implementations

determinative functions

the functions expected to have the greatest influence on the form of the final design. These are placed near the top of a function structure diagram

Function Sequence

a series of closely-related functions that must be carried out in a particular order

Concept Fragment

a possible solution to achieve a particular function

Brainstorming

Discussion where ideas are shared as soon as they come to mind and are quickly documented by a facilitator

Brain Sketching

ideas are all slightly written or sketched by individuals and later shared, discussed, and expanded upon. draws quieter members to contribute

Idea Card Method (Brain Sketching)

sketch until you can no longer form an idea, draw a card from the left, add and modify and pass to the right

Pool Method (Brain Sketching)

participants either generate a new idea or draw a card and modify, work at their own pace

Method 6-3-5

6 participants prepare 3 rough solutions by sketching for 5 minutes, pass to the right and add 3 additional ideas or modifications based on the ideas they recieve

Analogies

natural way in which to generate ideas to solve a problem. Viewing the problem at hand as being similar to another problem that already has a solution may reveal new solutions

Inverses and Extremes

involves viewing the problem in new and, often, unrealistic ways

Winnowing

screen all concepts and eliminate the candidates with the least chance of success (high risk) coupled with a low value

Ranking

The second step is to rank the remaining candidates based on relative value. To do this, the concepts need to be examined more closely (i.e. we need a better idea of how they will work, what they will look like, and so on); therefore, more effort per concept is required at this stage.

Scoring

The third step is to score the top ranked concepts based on a set of evaluation criteria (such as performance and cost, for example) in order to better estimate concept value. Compared to ranking, even more detail for each concept is required,

Is the concept feasible? Does it meet requirements? Is the necessary technology available?

Winnowing Questions

Pugh Chart

evaluation tool that qualitatively ranks concepts across a number of differ- ent criteria by comparing each concept to a refer- ence concept (datum)

Critical Path

the sequence of tasks that determine the shortest possible project duration

CPM Chart

Critical Path Method, used to determine how project tasks relate to one another and to identify which series of tasks determine the minimum completion time for the project

Identify all of the major tasks involved in the project and estimate their durations

Determine dependencies between tasks and use a CPM chart to sketch the task relationships

Determine the critical path from the CPM chart

Assign responsibilities for the tasks and allocate resources

Prepare a Gantt chart based on the dependencies from the CPM chart and the responsibilities determined above

Use of CPM and Gantt Charts

PERT

Project Evaluation and Review Technique is used to account for uncertainty in estimating task duration. It is based on combining estimates of expected, worstcase, and best-case task durations.

I/E

Introversion/ Extraversion: is our focus directed inwards (I) or outwards (E)

S/N

Sensing / iNtuition: are we focussed on the details (S) or the big picture (N)

T/F

Thinking/ Feeling: are decisions based on logic (T) or values (F)

J/P

Judging / Perceiving: do we like to have decisions made (J) or options open (P)

Imagine, Model, Compare and Judge

Steps in an Estimate

Imagine

consider the relevant physics and important parameters in the problem

Model

develop the mathematical model and carry out the estimate

Compare and Judge

check to see that your estimate makes sense by comparing the result to another value or estimate

3g

weight of a penny

1mm/s

speed of wristwatch minute hand

1 mm/s²

centripetal acceleration of wall clock minute hand

1 Pa

sheet of paper resting on flat surface

2 mJ

Energy of Bee in flight

4 W

power of an incandescent night light

2 mm

thickness of a DVD

1250 m

elevation of grouse mountain

980 m/s

fastest manned air-craft

30 m/s²

space shuttle take-off

1000 kg

weight of small car

750 N

weight of one person

20 MPa

Pressure in scuba tank

9 kJ

Energy in AA Battery

2 kW

Power in Small Lawn Mower Engine