Usability
WEEK 1 (Introduction)
- Usability „ease of use”
The extent to which a product can be used by speci ed users to acheive speci ed
goals with e ectiveness, e ciency, and satisfaction in a speci ed context of use.
- Usability goals
• E ecitve
• E cent
• Safe to use
• Right functionality
• Easy to learn its usage
• Usage easy to remember
- Interaction Design (umbrella term for many subdisciplines of design leds)
Purpose: interactive products support the way people communicate and interact in
their everyday and working lives.
- User Experience
Q: How do people experience a spec c product?
• Looking at the enjoyment and satisfaction during use (looks, interface etc.)
• „Every product used by someone has a user experience”
• e.g. of a success story: Apple Products
- Usability vs User Experience
Di erences:
• Potential Con icts: can a product be enjoyable as well as safe?
• Di erent goals and how measure these
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, - Daily Challenges: People do not use all the functions of the objects on the daily
basis;
- Usability Concepts
• A ordance
The quality or property of an object that defines its possible uses or makes
clear how it can or should be used; Possibilities that are easy to discover
Indication of use without explanation
> Visual A ordance: Observed and present properties of An object that
indicate how you use it
> phycial a ordance: e.g. chair - sit on it/ lift it
> virtual a ordance: e.g. Arrows on the web
Design for Humans
Two Basic principles by Norman:
• Make the method of use visible
• Use a good conceptual model
• Conceptual model
People make their own image of how something works; Understanding its
precise operation is not necessary;
e.g. scissors - model suggests usage by parts and these are connected
• Visibility
Hidden functions lead to problems e.g. when number of functions is greater
than number of buttons
With visible functionality, the user does not have to remember the use of an
object
e.g. bathroom faucets - two functions hot/cold; on/o
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, • Mapping
Relationship between button and action/result
e.g. light switch, stove, remote controller
• Feedback
Object let a user know what is happening (e.g. beep, light, display)
> can be a physcial change (e.g. stove ames)
• Constraints
Limiting the use of speci c object to make sure people use it in a correct
way.
- limitation of the number of possible Actions
- prevent Selection of wrong options
- physical objects often have constraints
! Also software constraints !
• Consistency
Design interfaces with similar functions and elements for similar tasks
e.g. keyboard shortcuts
Drawbacks:
- what if several tasks start with the same letter?
- use di erent combinations?
- breaks with consitency
- the increases the learning curve for users and the risk of making erros
Interal consistency - operations behave the same way within an application
External consistency - Operations, interfaces, etc. are similar in several
applications and machines
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, • Conventions
As users we have already a set of accepted learned norms and standards,
which were determined by culture etc., they can be ariti cal, arbitrary,
learned
- KEY
• Display current status and alternatives
• A good conceptual model is necessary
• Use mapping to indicate relationships
• User must receive continuous feedback
• Use a ordances
WEEK 2 (Interfaces)
- Interface
Place where communciation takes place between independent systems
- User interface (OR Human Computer Interface)
Part in which people communicate/interact with systems/machines
• Software
• Input (e.g. user control system - Tapping a touchscreen)
• Output (e.g. system shows e ect of control -playing a video)
- User interface and Usability
Extent to which the design of a user interface takes into account the psychological and
physcial characteristics of people, as well as, attention for E ective, E cient and
Pleasant use.
- Types of Interfaces
A. Command- line
A text based way to interact with a computer. Instead of clicking buttons or
icons, user types commands to tell the computer what to do.
- Its e cient, accurat and fast
- Used at scripting (running commands at once)
B. Graphical User
Allows users to interact with electronic devices through graphical icons and
4
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WEEK 1 (Introduction)
- Usability „ease of use”
The extent to which a product can be used by speci ed users to acheive speci ed
goals with e ectiveness, e ciency, and satisfaction in a speci ed context of use.
- Usability goals
• E ecitve
• E cent
• Safe to use
• Right functionality
• Easy to learn its usage
• Usage easy to remember
- Interaction Design (umbrella term for many subdisciplines of design leds)
Purpose: interactive products support the way people communicate and interact in
their everyday and working lives.
- User Experience
Q: How do people experience a spec c product?
• Looking at the enjoyment and satisfaction during use (looks, interface etc.)
• „Every product used by someone has a user experience”
• e.g. of a success story: Apple Products
- Usability vs User Experience
Di erences:
• Potential Con icts: can a product be enjoyable as well as safe?
• Di erent goals and how measure these
1
ffff
ffi
ff ff fl ffi fi fi fi fi fi
, - Daily Challenges: People do not use all the functions of the objects on the daily
basis;
- Usability Concepts
• A ordance
The quality or property of an object that defines its possible uses or makes
clear how it can or should be used; Possibilities that are easy to discover
Indication of use without explanation
> Visual A ordance: Observed and present properties of An object that
indicate how you use it
> phycial a ordance: e.g. chair - sit on it/ lift it
> virtual a ordance: e.g. Arrows on the web
Design for Humans
Two Basic principles by Norman:
• Make the method of use visible
• Use a good conceptual model
• Conceptual model
People make their own image of how something works; Understanding its
precise operation is not necessary;
e.g. scissors - model suggests usage by parts and these are connected
• Visibility
Hidden functions lead to problems e.g. when number of functions is greater
than number of buttons
With visible functionality, the user does not have to remember the use of an
object
e.g. bathroom faucets - two functions hot/cold; on/o
2
ff ffff ff
, • Mapping
Relationship between button and action/result
e.g. light switch, stove, remote controller
• Feedback
Object let a user know what is happening (e.g. beep, light, display)
> can be a physcial change (e.g. stove ames)
• Constraints
Limiting the use of speci c object to make sure people use it in a correct
way.
- limitation of the number of possible Actions
- prevent Selection of wrong options
- physical objects often have constraints
! Also software constraints !
• Consistency
Design interfaces with similar functions and elements for similar tasks
e.g. keyboard shortcuts
Drawbacks:
- what if several tasks start with the same letter?
- use di erent combinations?
- breaks with consitency
- the increases the learning curve for users and the risk of making erros
Interal consistency - operations behave the same way within an application
External consistency - Operations, interfaces, etc. are similar in several
applications and machines
3
ff fi fl
, • Conventions
As users we have already a set of accepted learned norms and standards,
which were determined by culture etc., they can be ariti cal, arbitrary,
learned
- KEY
• Display current status and alternatives
• A good conceptual model is necessary
• Use mapping to indicate relationships
• User must receive continuous feedback
• Use a ordances
WEEK 2 (Interfaces)
- Interface
Place where communciation takes place between independent systems
- User interface (OR Human Computer Interface)
Part in which people communicate/interact with systems/machines
• Software
• Input (e.g. user control system - Tapping a touchscreen)
• Output (e.g. system shows e ect of control -playing a video)
- User interface and Usability
Extent to which the design of a user interface takes into account the psychological and
physcial characteristics of people, as well as, attention for E ective, E cient and
Pleasant use.
- Types of Interfaces
A. Command- line
A text based way to interact with a computer. Instead of clicking buttons or
icons, user types commands to tell the computer what to do.
- Its e cient, accurat and fast
- Used at scripting (running commands at once)
B. Graphical User
Allows users to interact with electronic devices through graphical icons and
4
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