2. Summary
Introduction
Limitations of the Notations
Using a CDs to Evaluate i* Notational
System
Using Empirical Evaluation to GOMS
Extending i* to Support HCI Concepts
Conclusions
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3. Introduction
Task Analysis: is an approach that involves
different techniques addresses to describe
interaction between users and
environment in a systemic way.
Framework i*: is a goal-oriented language
and RE notation.
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4. Introduction
GOMS:
Model is based on the mechanism of human reasoning
to solve problems;
Represents activities (physical and mental) that involves
work.
Goals “user desires”
Operations basic units of perception, motor or
cognitive;
Methods Possibilities to reach operations.
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5. Introduction
Hierarchical Task Analysis (HTA):
Approach top-down which consider goals of
high-level and actions to reach goal.
Goal is a desired state;
Tasks describe how to reach this goal;
Operations are lower-level units to describe
behavior;
Plans which specify the conditions to perform
tasks or sub-tasks.
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7. Typical example of GOMS
notations
GOAL: CLOSE-WINDOW
. [select GOAL: USE-MENU-METHOD
. MOVE-MOUSE-TO-FILE-MENU
. PULL-DOWN-FILE-MENU
. CLICK-OVER-CLOSE-OPTION
GOAL: USE-CTRL-W-METHOD
. PRESS-CONTROL-W-KEYS]
For a particular user:
Rule 1: Select USE-MENU-METHOD unless another
rule applies
Rule 2: If the application is GAME,
select CTRL-W-METHOD
If there is more than one alternative, we could suggest series of conditions and
rules to take the best options (Method):
METHODS: IF (EXPERT-USER)USE-KEYBOARD-METHOD
ELSE USE-MOUSE-METHOD
We could decompose the goals in subgoals:
GOAL: EDIT-DOCUMENT
GOAL: OPEN-DOCUMENT
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8. Limitations of the Notations
Limitations on the Concepts:
Design does not satisfy requirements (both)
The option the user should chose (both)
What tasks should be execute (both)
What sequence should be followed in order to execute
some task (i*)
How to finish some task execution (i*)
Constraints are not represented (GOMS)
Only considers error-free behavior (GOMS)
The kind of user and his or her unpredictability are
disregard (GOMS)
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9. Limitations of the Notations
Limitations on the Process
the information related to system and user is
quite ad hoc. (Both)
methodologies do not allow conflicts to be
identified between design decisions and
requirements. (Both)
does not have some kind of traceability to
support the development of a design that
satisfies requirements (Both)
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10. Limitations of the i*
Graphical Notations
a) semiotic clarity;
b) symbols overload (homographs);
c) perceptual discriminability;
d) complexity management;
e) perceptual directness.
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11. Using a CDs Questionnaire to
Evaluate i*
Cognitive Dimensions Questionnaire:
Goals:
Evaluate the usability of information based-on
artifacts and notations;
It is proposed as a user-centered discussion
tool in order to make quick but useful
evaluations.
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12. Considerations about
Evaluation of i*
CDs:
Generated good concepts;
Captured important aspects of i* framework
and its notational system;
Allowed general users to make judgments and
reach agreement among themselves about i*
framework .
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16. Conclusions
The main contribution of this work has
been to introduce framework i* as an
alternative to help process in HCI;
The improvements propose in this are
intended to improve the communication
between different users;
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17. Conclusion
In order to be more meaningful and
useful, task analysis should be developed
through and interdisciplinary collaborative
effort, involving the various viewpoint of
ER and HCI.
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18. Future works
We propose to use Cognitive Dimensions Questionnaire to
evaluate GOMS;
It is necessary to extend the empirical evaluation to identify
strengths and weaknesses of GOMS;
It is required to make experiments using the modifications
proposes in i* notations;
It necessary to make new analysis of i* notations but it
should be focused on visual representation aspects, which
the CDs framework had excluded.
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