Some examples of Bad design

Example 1

• For the bell to ring,  the timer must be turned to  greater than 15 minutes, and then set to the  appropriate time

• Not very Intuitive!!!

• Both sides of the  refrigerator are  identical

•There is no handle on  the front

• How do you open the fridge

Imperceptible!!!

• What is this sign telling motorists to do?

• Check out

• http://www.baddesigns.com/examples.html

Difficulties using Every Day Products

Estimated Numbers with Functional Difficulty in the UK

• Dexterity – 1.7 Million

• Reaching and Stretching – 1.2 Million

• Manipulating and Gripping- 0.3 Million

• Lifting and Transporting – 0.6 Million

Difficulties with Everyday Products

Difficulties with Kettles

• Manipulation and gripping 273,000 • Lifting and transporting 615,000

Manipulation

The order of difficulty of packaging products (1 being the easiest) is shown in the table

below:• 1 Cleaning solution• 2 Washing up liquid• 3 Soup tin• 4 Sugar• 5 Washing powder/liquid• 6 Tin of tuna• 7 Butter• 8 Milk• 9 Microwave meal

packaging• 10 Bread packaging

• 11 Tea bag• 12 Instant soup

packaging• 13 Meat tin• 14 Plastic bottle• 15 Toothpaste• 16 Cereal packaging• 17 Cheese packaging• 18 Jam jar• 19 Shoe polish tin

Gripping

• 1 Cleaning solution• 2 Microwave meal

packaging• 3 Instant soup packaging• 4 Soup tin• 5 Washing powder/liquid• 6 Sugar• 7 Milk• 8 Washing up liquid• 9 Bread packaging

• 10 Butter• 11 Tea bag• 12 Tin of tuna• 13 Plastic bottle• 14 Cheese packaging• 15 Meat tin• 16 Toothpaste• 17 Shoe polish• 18 Cereal packaging• 19 Jam jar

Lifting

• 1 Shoe polish• 2 Tin of tuna• 3 Tea bag• 4 Instant soup packaging• 5 Meat tin• 6 Cleaning solution• 7 Butter• 8 Bread packaging• 9 Cheese packaging• 10 Plastic bottle• 11 Milk

• 12 Jam jar• 13 Toothpaste• 14 Cereal packaging• 15 Soup tin• 16 Washing powder/liquid• 17 Sugar• 18 Microwave meal

packaging• 19 Washing

Transporting• Packaging products - transporting• Products excluded from the list because of small sample numbers include;• • No excluded products• 34• 1 Cleaning solution• 2 Tea bag• 3 Instant soup packaging• 4 Toothpaste• 5 Milk• 6 Bread packaging• 7 Cereal packaging• 8 Plastic bottle• 9 Tin of tuna• 10 Jam jar• 11 Butter• 12 Washing powder/liquid• 13 Microwave meal packaging• 14 Sugar• 15 Washing up liquid

Capacity Demands(Capability Demands Clarkson)

• Looking at the above milk bottle designs:• Each bottle design demands that the user has a

capacity to perform a vertical lift by gripping the handle with a closed fist grasp.

We see that the bottles on the left will allow a greater range of hand sizes get a proper grip on the handle for lifting since it gives greater clearance dimension between handle and jug

• In other words the structure of each bottle implies the user must have particular hand dimensions in order to manipulate the bottle

• Thus each bottle places different demands on the user attributes.

• If these demands are not met then the bottle cannot be used.

• This conflict is the essence of how capacity demands define the guards of our petri nets

• The above is an example of an object capacity demand.

• There are other kinds of capacity demands based around action

• These must be measured against the personal capacities of the agent and the attributes of the environment

• This is summarised in the following

Capacity Demands

Action and

Objects

Agent Capacities,EnvironmentalFactors,State Attributes

More formally

Person Capability Tokens

EnvironmentAttribute Tokens

Action Capability Demands

Object Capability Demands

Environmental Demands

Incoming Tokens representing

Person and State

Transition Guard representing Barriers

( in terms of Capability Demands)

State

Capacity Demands And Assistive Technology

• Action and objects place capacity demands on people and environment.

• For example using a standard kettle involves a capacity demand of being able to perform a vertical lift of up to 1 kg(which is the weight of the kettle when full with water), one handed using a closed fist grip.

• Assistive Technology changes the relation between personal and environmental capacities and the capacity demands of the action being executed.

• This relationship is represented by the guard of the CPN• This is shown in the following example