2. Input & Output Technologies
• Input: the process that occurs as information from inside the user’s head or
from the environment is transformed into the sort of data that computers
can use
• Output: the process of re-representing computer data into a form that the
user can comprehend and make use of.
3. Interaction Styles
• all the ways the user can communicate or otherwise interact with the
computer system
1. Command Language
2. Menu Selection
3. Form fill-in
4. Natural Language
5. Direct Manipulation
4. Command Language
(Advantages)
• Flexible.
• Appeals to expert users.
• Supports creation of user-defined
"scripts" or macros.
• Is suitable for interacting with
networked computers even with
low bandwidth.
5. Command Language
(Disadvantages)
• Retention of commands is generally very poor.
• Learnability of commands is very poor.
• Error rates are high.
• Error messages and assistance are hard to provide because of the diversity
of possibilities plus the complexity of mapping from tasks to interface
concepts and syntax.
• Not suitable for non-expert users.
6. Form fill-in
• Pay roll system, financial systems
• Advantages
• Simplifies data entry.
• Shortens learning in that the fields are predefined and need only be 'recognized'.
• Guides the user via the predefined rules.
• Disadvantages
• Consumes screen space.
• Usually sets the scene for rigid formalization of the business processes
8. Menu Selection
(Advantages)
• Ideal for novice or intermittent users.
• Can appeal to expert users if display and selection mechanisms are rapid and if
appropriate "shortcuts" are implemented.
• Affords exploration (users can "look around" in the menus for the appropriate
command, unlike having to remember the name of a command and its spelling
when using command language.)
• Structures decision making.
• Allows easy support of error handling as the user's input does not have to be parsed
(as with command language).
9. Menu Selection
(Disadvantages)
• Too many menus may lead to information overload or complexity of
discouraging proportions.
• May be slow for frequent users.
• May not be suited for small graphic displays.
11. Natural Language (English)
• Advantages
• Intuitive and potentially powerful
• Can be used for simple interactions (e.g. telephone booking systems where users select
from a list).
• Disadvantages
• Technological limitations
• Ambiguity
12. Direct manipulation
• Visibility of objects of interests
• Rapid , reversible incremental actions performed directly on them
• Replacement of complex command language by direct manipulation object
of interest
• Direct manipulation tries to bridge gulf of execution and evaluation
13. Direct Manipulation
(Advantages)
• Visually presents task concepts.
• Easy to learn.
• Errors can be avoided more easily.
• Encourages exploration.
• High subjective satisfaction.
• Recognition memory (as opposed to cued or free recall memory)
14. Direct Manipulation
(Disadvantages)
• May be more difficult to program
• Not suitable for small graphic displays.
• Spatial and visual representation is not always preferable.
• Metaphors can be misleading since the essence of metaphor is understanding
and experiencing one kind of thing in terms of another
• Compact notations may better suit expert users
16. Ubiquitous computing
• A concept in software engineering and computer science where computing is
made to appear everywhere and anywhere
• Can occur using any device, in any location, and in any format
• 3 basic forms for ubiquitous system devices
• Tabs: wearable centimeter sized devices
• Pads: hand-held decimeter-sized devices
• Boards: meter sized interactive display devices.
17. Mobile Computing
• Input method is finger
• Precision is lost
• Android design guidelines
• RIFD
