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  • Trevis:
    Tool for Rapid Evaluation of interactive Systems


    Tool Trevis can make predictions of the usability of interactive systems. Usually these predictions are made by preforming experimental tests with test persons and prototypes. The disadvantage of this proceeding is that prototypes are only available at late stages of the development process. Predictions in early stages of the development process are reasonable and important because changes in the system design can be realized much faster and cheaper.
    The presented tool offers the possibility to make this early predictions of usability and allows to make important decisions in early stages of the development process which by noware not sufficiently supported by applicable software tools.

    The tool integrates formal and experimental evaluation methods which can be applied separately as well as in combination. Trevis makes a continuous and universal evaluation through all stages of the system's life circle possible.
    For formal evaluation the GOMS theory (Card, Moran & Newell) is used, which can give a formal description of normative user behaviour in terms of user models. The analysis of these user models makes predictions of usability by providing statistical measures. For instance, it is possible to estimate the execution and the learning time of the performing actions to reach a goal of a task.
    Besides a user model analysis a comparing validation of different alternative design concepts can be performed.
    After an experimental evaluation of the examined system using a prototype and test persons the generated empirical action logs can be imported and analysed with Trevis. These action logs contain information about the actually performed actions of the test persons. A comparison with user models which describe the actions of a "perfect user", provides a lot of more information about the usability of the examined system (i.e. error frequencies, absolute and relative deviations).
    Trevis could prove its usefulness in a couple of different smaller projects.


    For additional information about Trevis please have a look at the following selected publications (versions to download can be found here: Publications):


    A demo version of Trevis is available for download. The demo has the following features:
    To run the demo you need the Java 2 Runtime Environment v1.3. If the JRE (Java Runtime Environment) is not yet installed on your computer, please download it from the JRE homepage. Setup instructions for Solaris, Linux and Windows can also be found there.
    Please download the file trevis-demo.zip (1.2 MByte) and unzip it into a directory of your choice:


    The zip-file contains:
    bib - directory which contains the Trevis library of standard GOMS operators
    user - directory which contains the sample project
    trevis.jar - the executable jar archive
    trevis-kurzanleitung.pdf  a short user guide (in german, english version is following soon) which is also available separately here.

    Execute the demo by a double click on trevis.jar or entering the following command line:

    java -jar trevis.jar

    Then please follow the steps in the user guide. If you have problems with executing or working with the demo, please contact us (see below).