This slideshow for HUMAN COMPUTER INTERACTION subject

1. HUMAN COMPUTER
INTERACTION
Subject Code : DCM 214
CHAPTER 1
PRINCIPLE AND GUIDLINES
Prepared by : NURAINI MOHD GHANI 1

2. Related Fields
"Human-computer interaction is a discipline concerned with the design, evaluation and
implementation of interactive computing systems for human use and with the study of major
phenomena surrounding them." Association for Computing Machinery
–Equivalent terms are CHI and MMI
–Usability Engineering focuses on design and implementation process
Earlier fields of Human Factors & Ergonomics
–More stress on physical issues; and on optimising (work) processes; concerns
interaction with all kinds of human artifacts
User Interface Design
–Focus on interface, i.e. tends to assume deeper function is fixed
User/Human Centred Design
–Approach to software engineering with user focus at all stages
–Participatory Design explicitly includes users in design process
Interaction Design
–Wider scope than computer, and more emphasis on cognitive/
experiential factors than traditional HF.
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3. HCI in the design process
Waterfall Model
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4. HCI in the design process
The spiral lifecycle model (Boehm, 1988) ;
Importance of interaction in good design.
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5. HCI in the design process
Agile development e.g. eXtreme Programming
(agilemanifesto.org): emphasises tight iteration in short
timescales, close collaboration with customer
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6. General Framework
Task
Articulation Performance
Input
Human Computer
Output
Observation Presentation
Interface
Complex problem : we don’t have a full of
the part, or their interaction.
Note that a particular desired outcome may
be achieved by changing any one of these
factors or interaction.
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7. Why is interaction difficult?
Examples of errors
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8. Why is interaction difficult?
The problem from the human perspective
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9. Why is interaction difficult?
The problem from the human perspective
This is called the ‘Action Cycle’ following Norman
(1988)
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10. Norman’s Action Cycle
Norman proposed that
actions are performed in
cycles:
1.Establish a goal
2.Execute the action
3.Evaluate the action
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11. Norman’s Action Cycle
2.Stages of execution
A. Form a plan for the task, a sequence
of system operations to be performed on
system entities .
B. Translate the plan into an action
specification consistent with the
interface ‘input’ language.
C. Output the action specification
as a sequence of lexical tokens using the
system input devices.
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12. Norman’s Action Cycle
3.Stages of evaluation
D. Observe the system
response as e.g., visual,
auditory tokens
generated by output
devices .
E. Interpret the output in
terms of changes in the
system state, e.g.,
entity properties.
F. Determine whether the
new system state is
consistent with what was
intended
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13. Errors
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14. Errors
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15. Errors
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16. Design Rules for HCI
#Many sets of rules have been proposed
to encapsulate understanding and best
practice
–Operate at various levels
#principles
–abstract design rules
–“an interface should be easy to navigate”
#guidelines
–advice on how to achieve principle
–may conflict; understanding theory helps resolve
–“use colour to highlight links”
#standards
–specific rules, measurable
–“MondoDesktop links are RGB #1010D0”
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17. Design Rules for HCI
ISO 9241, Ergonomic of Human System Interaction,
adopt traditional usability categories with specific
measure. E.g.:
Usability Effectiveness Efficiency Satisfaction
Objective measures measures measures
Suitability for the Percentage of goal Time to complete a Rating scale for
task achieved task satisfaction
Appropriate for Number of power Efficiency relative to Rating scale for ease
trained users features used expert user of learning
Lean ability Percentage of Time to learn Rating scale for ease
functions learned criterion of learning
Error tolerance Percentage of error Time spent on Rating scale for error
corrected correcting errors handling
successfully
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18. Design Rules for HCI
Shneiderman’s 8 Golden Rules (1987) :
*Strive for consistency
*Enable frequent users to use shortcuts
*Offer informative feedback
*Design dialogs to yield closure
*Offer error prevention and simple error
*Permit easy reversal of actions
*Support internal locus of control
*Reduce short-term memory load
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19. Design Rules for HCI
Norman’s 7 principles (1988):
*Use both knowledge in the world and
knowledge in the head
*Simplify the structure of tasks
*Make things visible
*Get the mappings right
*Exploit the power of constraints, both natural
and artificial
*Design for error
*When all else fails, standardize
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20. Design Rules for HCI
Nielsen’s 10 usability Heuristics (1994):
*Visibility of system status
*Match between systems and the real world
*User control and freedom
*Consistency and standard
*Help users recognize, diagnose and recover from
error
*Error prevention
*Recognition rather than recall
*Flexibility and efficiency of use
*Aesthetic and minimalist design
*Help and documentation
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21. Consolidate the three lists here. Mark
any you don’t understand with *
Eg : Consistency (Nor 7, Shn1, Nie 4)
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22. Usability Principle form Dix
Chapter7
Learn ability
*the ease with which new users can begin effective
interaction and achieve maximal performance
Flexibility
*the multiplicity of way the user and system
exchange information
Robustness
*the level of support provided to the user in
determining successful achievement of goal-
directed behavior
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23. Where do these rules come from?
Many seem like common sense - but often violated
*Home exercise :pick one everyday object and one piece of
software and assess with respect to these rules.
Some are grounded in our understanding of how
humans perceive, think and learn.
Some are the result of empirical study.
Some are derived from particular characterisations of
the nature of human action
Some are collection of experience
In this course we will study the background and
justification of these rules and elaborate on how the can
be applied in specific contexts.
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24. THANK YOU
SEE YOU NEXT CLASS
AND
DON’T FORGET FINISH
YOUR HOMEWORK
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