Abdelwaheb Trabelsi

Incorporating usability requirements into model transformation technologies

Abstract Model transformation plays a key role in the model-driven engineering (MDE) approach. In fact, it describes the process of converting one model into another of the same system. Considering a source model, there may be several ways to transform it into target models. Although alternative target models may be equivalent from the functional viewpoint, they may differ in their usability attributes. One of the key challenges for an automated transformation process is to identify which model transformations will produce a target model with the desired usability attributes. The present paper addresses this issue and provides a parameterized transformation to deal with usability driven in an MDE approach. Specifically, it focuses on how to associate usability attributes with the different alternative transformations and how this can be taken into account in an automated transformation process to obtain user interface model with the desired usability attributes.

Widgets Dedicated to User Interface Evaluation

In this article, evaluation-based widgets are proposed as a contribution to assist evaluators for early evaluation of user interfaces. This contribution imbricates the ergonomic quality evaluation process into widgets used for user-interface graphical composition. In other words, these widgets evaluate themselves according to a defined set of ergonomic guidelines. The proposed widgets indicate the possible interface design ergonomic inconsistencies as a notification to the designer. The guidelines set can be modified through an interface dedicated to guidelines definition into XML files. The proposed widgets are intended for the evaluation of different kind of user interfaces: WIMP, web, and mobile. An experimental evaluation, involving these evaluation-based widgets, is proposed to illustrate and to validate the approach.

A model-driven approach for usability engineering of interactive systems

Abstract Usability is considered to be one of the most important quality factors that determine the success/failure in the actual use of an interactive system. This can explain the ever-increasing number of publications addressing the problem of usability evaluation. However, most of these proposals only consider usability evaluations after the application is fully implemented and deployed. Some others are based on reviewing usability principles in intermediate artifacts with regard to their conformance with a set of guidelines. Since the traceability between these artifacts and the final application is not well established, performing usability evaluations by considering these artifacts as input may not ensure the usability of the final application. This problem may be alleviated by using a model-driven engineering (MDE) approach due to its intrinsic traceability mechanisms that are established by the transformation processes. The present paper aims to delineate a method for evaluating usability throughout an MDE development life cycle by considering conceptual models as input. To do this, two main contributions are proposed. The first one, called usability-driven model transformation, aims to ensure that an intermediate artifact with the required level of usability is generated. It controls the model transformation process according to a set of usability attributes. The second contribution, called early usability evaluation, performs the usability evaluation from the conceptual models by defining metrics based on conceptual primitives that constitute the conceptual models. This evaluation would be a significant advantage with regard to saving time and resources. The early usability evaluation is empirically validated by comparing the usability measure obtained by our proposal and the level of usability perceived by the end-users.

Graphical controls based environment for user interface evaluation

For more than two decades, the HCI community has elaborated numerous tools for user interface evaluation. Although the related tools are wide, the evaluation remains a difficult task. This paper presents a new approach for user interface evaluation. The proposed evaluation process focuses on utility and usability as software quality factors. It is based on the UI ergonomic quality inspection as well as the analysis and the study of the Human-Computer interaction. The proposed approach is mainly based on graphic controls dedicated to the user interface evaluation. These controls have, on the one hand, the role to compose graphically the interfaces. On the other hand, they contribute to the UI evaluation through integrated mechanisms. The evaluation is structured into two phases. The first consists of a local self-evaluation of the graphical controls according to a set of ergonomic guidelines. This set is specified by the evaluator. The second allows an electronic informer to estimate the interaction between the user interface (graphically composed by the evaluation based controls) and the user.

Towards ergonomic guidelines integration within graphical interface controls for the evaluation of the interactive system Application to a transport network Information Support System

In this paper, a new approach for interactive system evaluation is presented. It is based on the ergonomic guidelines integration within Graphical User Interface (GUI) controls. These controls provide assistance to the evaluator for the interfaces design according to a set of ergonomic guidelines. The controls use is proposed for both the evaluators and the developers. The proposed approach is based on the fact that when creating a graphical component (when adding it to the interface), it inspects a set of ergonomic criteria and verifies the GUI compliance with these criteria. The advantage of the suggested proposal consists essentially on its easiness to provide ergonomic guidelines validation when designing a GUI. To validate our approach, we propose in this paper, an application on a transport network supervision system and more particularly to an Information Assistance System for passenger.

Towards optimizing the usability of user interface generated with model-driven development process

Usability is crucial to determine the success/failure of the user interfaces. This can explain the ever-increasing number of publications addressing the problem of usability integration during the development process. These studies aim to guide the development process of the user interface according to a set of usability attributes. In fact, the selection of the alternative transformation depends on the usability attributes that will be met. However, the major weakness of these studies is related to the choice of the optimal alternative model transformation. The present paper introduces an approach that addresses this weakness and generates the user interface conceptual model with an optimal usability. The main objective is to select from all the possible alternative transformations the optimal one which maximizes the usability value in a specific context (e.g., small-screen device, novice user). By considering the inherent features of the model-driven engineering, the proposed approach aims to generate the final user interface with an optimal usability value.

Model-driven Engineering for Optimizing the Usability of User Interfaces

Usability is considered to be one of the most important quality factors that determine the success or failure of an interactive system. This can be explained by the ever-increasing number of studies addressing the integration of the usability evaluation at the development process. However, most of these proposals aim to guide the user interface transformation process according to a set of usability criteria allowing the generation of user interfaces which meet the usability requirement. In fact, the selection of the adequate alternative transformation depends on the usability attributes that will be met. This paper proposed an approach that considers the user interface generation process as a usability optimization problem according to given usability optimization objectives. The aims to generate all possible concrete user interfaces from a given abstract user interface. Then, the usability optimization process selects the optimal concrete user interface for a specific context of use.

A framework for supporting the choice of usability evaluation methods for interactive adaptive systems

The evaluation of interactive adaptive systems is considered as a difficult endeavour due to the complex nature of these systems. Issues arise in the need to identify, for a given evaluation situation the set of suitable usability evaluation methods to be used by the evaluators. This paper describes a framework for supporting the choice of appropriate methods for the usability evaluation of interactive adaptive systems. It is based on the comparison of usability evaluation methods using relevant criteria. This framework is then validated through a case study; it concerns an adaptive hypermedia system in transportation field.

A User-Oriented Test environment based on User-Interface evaluation graphical controls

Abstract Several user-oriented techniques have been proposed for Graphical User Interface evaluation. In this paper, we focus on User-Oriented Test concepts, advantages and related problems. Among the User-Oriented Test techniques, the electronic informer is a powerful technique for interactive system testing. Thus, this research paper contributes in the improvement of existing tools for interactive system evaluation. This environment is achieved using (1) an electronic informer dedicated to the interactive system evaluation and (2) evaluation based graphical controls. The proposed evaluation environment is structured following client-server architecture. It aims to automate the interactive system evaluation process. Besides it takes the evaluation process into account since early interactive system design phases. This environment is validated by an experimental test.

A decision-making approach for the synthesis of results issued from different user interface evaluation methods

The evaluation of the interactive systems has been the subject of numerous researches during the last two decades. However, it still remains a difficult task to establish. Generally, evaluators exploit a single method to proceed to an interactive system evaluation. However, many authors assert that a single method is not enough to obtain relevant evaluation results. As a solution, we propose a decision-making approach for the synthesis of data collected by different evaluation methods to obtain more reliable evaluation results. The proposed approach is based on three evaluation methods: the questionnaire, the ergonomic quality inspection and the electronic informer. As an evaluation result, the proposed approach provides evaluators with the quantification of the evaluation dimensions: the usability and the system functionality degree.