Elizabeth Suescún Monsalve

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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

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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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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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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Example decomposition of task

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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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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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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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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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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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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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Empirical Evaluation to GOMS

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HTA Notations

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Notation

Example

Extending i* to Support HCI Concepts

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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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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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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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Thanks

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