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i)Principles to support usability.
a)Learnability.
The ease with which new users can begin effective interaction and achieve maximal performance.
b)Flexibility.
The multiplicity of ways in which the end-user and system exchange information.
c)Robustness.
The level of support provided to the user in determining successful achievement and assessment of goals.
ii)Principles of Learnability.
a)Predictability.
Determining effect of future actions based on past interaction history operation visibility.
Refers to how the user is shown the availability of operations that can be performed next.
b)Synthesizability.
Assessing the effect of past actions immediate vs. eventual honesty.
c)Familiarity.
How prior knowledge applies to new system.
Guessability; affordance.
d)Generalizability.
Extending specific interaction knowledge to new situations.
e)Consistency.
Likeness in input/output behaviour arising from similar situations or task objectives.
iii)Principles of flexibility.
a)Dialogue initiative.
Freedom from system imposed constraints on input dialogue.
System vs. user pre-emptive.
System pre-emptive: system initiates all dialog, user responds to requests for information.
User pre-emptive: user is entirely free to initiate any action in the system .
b)Multi-threading.
Ability of system to support user interaction for more than one task at a time.
Concurrent vs. interleaving; multimodality.
c)Task migratability.
Passing responsibility for task execution between user and system.
Example: spell checking & spell checker.
d)Substitutivity.
Allowing equivalent values of input and output to be substituted for each other.
Representation multiplicity; equal opportunity.
e)Customizability.
Modifiability of the user interface by user (adaptability) or system (adaptivity).
iv)Principles of robustness.
a)Observability.
Ability of user to evaluate the internal state of the system from its perceivable representation
Browsability; defaults; reachability; persistence; operation visibility.
b)Recoverability.
Ability of user to take corrective action once an error has been recognized.
Reachability; forward/backward recovery; commensurate effort.
c)Responsiveness.
How the user perceives the rate of communication with the system.
Stability.
d)Task conformance.
Degree to which system services support all of the user's tasks.
Task completeness; task adequacy.
jim items answered the question on March 13, 2019 at 14:31
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