1. Human Computer Interaction Lecture 09 Interaction Paradigms

2. Metaphor
Relating computing to other real-world activity is effective teaching technique
LOGO's turtle dragging its tail
file management on an office desktop (First time used by Xerox Alto and Star)
financial analysis on spreadsheets
Keyboard use in word processor as a typewriter
virtual reality – user inside the metaphor
Problems
some tasks do not fit into a given metaphor
Scanning a file for viruses
cultural bias
It should not be assumed that a metaphor will apply across national boundaries

3. Direct Manipulation
Designers noted that their products were gaining popularity as their visual content increased
1982 – Shneiderman coined this phrase. He described
visibility of objects
incremental action and rapid feedback
syntactic correctness of all actions
replace complex command languages with direct actions (hence the term “direct” manipulation)
In 1984 – First Macintosh personal computer demonstrated the inherent usability of direct manipulation.

4. Direct Manipulation
Direct manipulation for the desktop metaphor requires files and folders to be made visible representing underlying files and directories
The model-world metaphor
What You See Is What You Get (WYSIWYG)

5. Hypertext key to success in managing explosion of information
mid 1960s – Nelson describes hypertext as non-linear browsing structure
hypermedia and multimedia

6. Multimodality
Mode: a mode is a human communication channel e.g. Visual, audio or haptic (touch)
Multimodality means simultaneous use of multiple channels for input and output
A multi-modal interactive system is that which relies on the use of multiple human communication channels.
We can say that all interactive systems are multimodal because all use at least two human channels i.e. Visual and hepatic

7. Computer Supported Cooperative Work (CSCW)
CSCW is collaboration of individuals via computer
Emerged with the advent of strong computer networks
CSCW removes bias of single user / single computer system

8. Computer Supported Cooperative Work (CSCW)
Can no longer neglect the social aspects
Electronic mail is most prominent success
A metaphor of conventional mail system
An example of asynchronous CSCW system
CSCW systems built to support users working in groups are referred to as groupware

9. The World Wide Web
Internet is simply a collection of computers linked together. WWW builds on top of it.
Hypertext, as originally realized, was a closed system
Simple, universal protocols (e.g. HTTP), mark-up languages (e.g. HTML) and global naming scheme (URLs) made publishing and accessing easy conceive
First envisioned by Tim Berners-Lee.
First text based browser in 1991
Several graphical browsers in 1993(Mosaic)

10. Agent-based Interfaces
People who work on someone’s behalf e.g. estate agents, travel agents, secret agents etc.
Software agents?
Software which act on behalf of users within electronic world e.g. web crawlers which search the WWW for documents that user might find interesting, spam filtering
Some agents use artificial intelligence techniques to learn, called intelligent agents.
E.g. Eager(performs repeated actions for the user)
Even some intelligent agents are there that don’t have a clear picture
Summing function of a Spreadsheet

11. “The most profound technologies are those that disappear.”
Ubiquitous Computing
Based on the idea of moving human-computer interaction away from the desktop and out into out everyday lives.
“The most profound technologies are those that disappear.”
Mark Weiser, 1991
Also called pervasive computing
Late 1980’s: computer was very apparent
How to make it disappear?
Shrink and embed/distribute it in the physical world
Design interactions that don’t demand our intention

12. Sensor-based and Context-aware Interaction
Embedment of computation even deeper, but unobtrusively, in our day-to-day life.
The user is totally unaware of the interaction taking place.
Information is gathered from sensors in Environment
Examples: Washbasin, automatic doors, lights turned on automatically
This information can be used to modify explicit interfaces, do things in background etc.

13. Sensor-based and Context-aware Interaction
Automatic sensing is an imperfect activity. So actions from these ‘intelligent predictions’ should be made with caution.
There are two principles of appropriate intelligence
Be right as often as possible, and useful when acting on these predictions
Do not cause excessive problems in the event of an action resulting from a wrong prediction
The failure of must intelligent systems in past resulted from following the first principle, but not the second.