Rosanna Cassino

Developing usable web interfaces with the aid of automatic verification of their formal specification

The development of interactive visual applications is a complex work, usually performed with the help of advanced visual programming environments. Although a number of tools are available to support designers and developers in the specification of a GUIs layout and behavior, and in the generation of the corresponding code that implements the interface, theoretical guidelines and/or semi-automatic mechanisms rely upon the knowledge of the designer to manage usability and accessibility issues. Indeed, the evaluation of the visual environments is traditionally performed by means of expert-based evaluations or by testing with end users. In this work we describe a methodology to specify and evaluate interactive visual environments, in particular web interfaces, based on the SR-Action Grammars formalism and we present a bottom - up approach to aid the designer to develop graphical applications that automatically respect a significant number of usability rules before the software is released and tested by standard methods. We show how it is possible to assess the usability metrics of consistency, completeness and user control by means of checks performed at a high level of abstraction. VALUTA (Automatic Tool for the Usability Verification at Abstract Level) is the implemented tool that allows developers to generate the formal specification of an interactive visual application in automatic manner, so to perform the related usability controls at a very early stage. Thanks to usability controls automatically performed at formal level, the designer can use the evaluation results to perform feedback analysis of the visual environment. The tool is applicable to an already existing interface, allowing the designer to evaluate its usability in the development of a more usable version. We have analyzed the home page of three web sites (www.lycos.it, www.google.it, http://it.mail.yahoo.com/) as a case study and we show the related evaluation report generated by the described approach.

Empirical validation of an automatic usability evaluation method

Abstract Today, the success of a software application strongly depends on the usability of its interface, so the evaluation of interfaces has become a crucial aspect of software engineering. It is recognized that automatic tools for graphical user interface evaluation may greatly reduce the costs of traditional activities performed during expert evaluation or user testing in order to estimate the success probability of an application. However, automatic methods need to be empirically validated in order to prove their effectiveness with respect to the attributes they are supposed to evaluate. In this work, we empirically validate a usability evaluation method conceived to assess consistency aspects of a GUI with no need to analyze the back-end. We demonstrate the validity of the approach by means of a comparative experimental study, where four web sites and a stand-alone interactive application are analyzed and the results compared to those of a human-based usability evaluation. The analysis of the results and the statistical correlation between the tool׳s rating and humans׳ average ratings show that the proposed methodology can indeed be a useful complement to standard techniques of usability evaluation.

SR-task grammars: a formal specification of human computer interaction for interactive visual languages

The paper describes a formal model to specify the syntax and semantics of interactive visual languages by SR-task grammars. The proposed approach provides language designers with a new type of grammars based on the formalism of symbol-relation grammars, where a new form of production rules allows to directly specify the interactive behavior of the visual environments described. Therefore, the language designer only has to define the development of a visual scenario depending on occurring events, and the changes of the state of a scene is regarded as the application of a rewriting rule.

Automatic Usability Evaluation of GUI: A Front-side Approach Using No Source Code Information

The usability of a software system and especially of its user interface now has become crucial and decisive for the success of the application itself. The usability evaluation can be performed by several techniques: classical methods such as tests are performed by experts or end users tester. These approaches require long and expensive testing phases. For this reason, in recent years there has been a rapid spread of automatic tools of evaluation, which allow achieving more objectives in a simple, rapid and economical manner. In this work, we describe an approach to evaluate the usability of a GUI analyzing only its graphical output. The implemented tool allows measuring any usability metrics of usability of the graphical interface of an application using a front-size technique that adopts image processing algorithms to identify and classify the interface components and an automatic interaction system to analyze the dynamic mechanisms. The approach is illustrated using the example of the analysis of a web interface.

An Integrated Environment to Design and Evaluate Web Interfaces

The advantage of many web publishing tools is the flexibility for the user to arrange the available widgets and modules. Nevertheless, the freedom to insert and arrange components in the creation of web pages sometimes leads the designer to make usability and/or accessibility mistakes that emerge only after the interface has been built and subjected to automatic, semi-automatic or manual evaluation processes. Several systems include features to perform accessibility controls of the web sites implemented, analyzing syntactic properties rather that provide guidelines to control the usability metrics. In this work, we propose a methodology to develop web interfaces that integrates the advantages of a top–down approach to implement HTML pages with functionalities to perform usability controls analyzing an abstraction level of formal specification based upon Symbol-Relation Action grammars (SR-Action grammars, for short) (Cassino and Tucci, Information Systems: People, Organizations, Institutions, and Technologies, 2009). In particular, the visual models adopted to develop both the static characteristics and the interactive tasks of the web application, makes more intuitive the design and the development. Again, a SR-Action grammar defining the scenes of the implemented site is used to control a subset of the Nielsen heuristics at abstraction level: completeness, correctness, aesthetic and minimalist design, user control, consistency, and metrics desirable in an interactive visual interface. The analysis at formal level and the report of the usability controls allow the designer to run feedback reviews of the visual environment under consideration and to perform usability evaluation before of the canonical testing techniques. Then, we describe an implementation prototype of the development environment born of the integration of two systems previously realized: TAGIVE (Cassino et al., WSEAS Trans Inform Sci Appl J, 2006) and VALUTA (Cassino and Tucci, Information Systems: People, Organizations, Institutions, and Technologies, 2009).

VALUTA: A Tool to Specify and Verify Interactive Visual Applications

This paper presents a system to specify and verify web applications, based on previous results on usability evaluation of interactive visual interfaces by means of checking their corresponding formal specification. In Cassino and Tucci we have described a methodology to design, specify and evaluate interactive visual interfaces, based on the SR-Action Grammars formalism, and we have presented a bottom – up approach to guide the designer to develop graphical user interface which respect any usability metrics before the software is released and tested by standard methods. TAGIVE (Tool for the Aided Generation of Interactive Visual Environments) is a visual environment for the implementation of interactive visual applications (html, xml, java applications), and for the generation of the underlying SR-Action Grammar specification. Now, we present VALUTA (Automatic Tool for the Usability V erification at A bstraction Level ), a tool that supports the generation of the formal specification of existing interactive visual applications in an automatic manner, so to perform the related usability controls. Checking the usability of interactive applications at a formal level, allows a designer to perform feedback analysis of the environment under consideration.

A system to support the integrated management of diagnostic medical images

Information systems are essential tools supporting the management of hospital organizations. The demand for availability and integration of data in this field is more and more increasing, basically for absolving two key issues: collecting and merging all the elementary data available for a patient during the hospitalization process, so that physicians and other operators get all the necessary information they need during the process; planning the development of the diagnostic activities/therapeutics to optimize the process. In this perspective, we present a system that integrates a booking subsystem for hospital specialized treatments booking (CUP), a subsystem for the management of the hospitalizations (including First Aid Departments), a subsystem for filing and reporting clinical images, a subsystem for the analysis of radiological images in a unique management environment. Therefore we describe a complete system for the management of an archive of digital dossiers for the patients of a hospital, where diagnostic imaging is a central issue.