eLearning I - VRML-based tutorial

With the publication of the Framework Directive 89/391/EEC and its subsequent implementation in national law, the evaluation of workplaces became mandatory, with computer workstations as the most widespread category. Consequently, we decided to develop a service that allows ergonomics students as well as occupational health practitioners to become acquainted with the evaluation task in this domain.

To ensure the transfer of the acquired knowledge, the service was based on the concept to simulate the evaluation procedure as accurately as possible. To allow a widespread utilization, the service was realized as an application for the World Wide Web (WWW), in the form of a web-based training (WBT), working on conventional computers and standard software.

The pivotal element of the application was a three-dimensional scenario of a computer workstation, which was presented as a VRML-model. The model included interactive elements mimicking those of real-world offices, allowing to open the door, the filing cabinet, and the drawers, moving the louvers up and down, switching the luminaries on and off, etc.

View of the computer workstation scenario (l.h.s) and the checklist specifying the ergonomic requirements (r.h.s).

To keep the download time of the scenario within acceptable limits, some details were displayed in separate popup windows (model pop-ups). An example are reflections on the screen, which were presented in a digital photo. The access of the model pop-ups was realized by defining hotspots, which changed the cursor to a pointing hand.

The users performed the evaluation by using a checklist for screening computer workstations according to the German labor protection laws. The checklist consisted of 38 items of two types, 13 items were concerned with the general spatial arrangement (e.g., 'Is the monitor completely supported by the desk and does not project beyond its surface?'), 25 items were concerned with object details (e.g., 'Is the screen without any glare and reflections?'). For each item an additional explanation was available, which was displayed in a separate popup window (checklist popup). The checklist pop-ups were retrieved by clicking on hyperlinks that were integrated in the text of the items.

With each item the response alternatives 'yes' and 'no' were presented as radio buttons. A 'yes'-response implied that the corresponding aspect of the computer workstation complied with the criterion specified in the item, a 'no'-response signaled an ergonomic deficiency. The deficiencies implemented in the scenario represented typical problems at computer workstations, e.g., the screen surface was not at a right angle with the window front. Based on these deficiencies, 20 of the 38 items were to be answered in a negative way.

Having completed the checklist, the users pushed a button that initiated the presentation of a feedback page. This page was almost identical to the submitted checklist, with the exception that the correct responses were marked by hyperlinks (the 'yes' or 'no' text of the radio buttons). Clicking on such a hyperlink, a feedback pop-up appeared, with an explanation why the marked alternative was the correct one. Moreover, at the end of the page the performance was summarized in a table, presenting the percentages of hits and false alarms, together with an explanation of these terms.

View of the computer workstation scenario (l.h.s) and the feedback about the accuracy of the responses (r.h.s).

The access to the WBT required filling a registration form, in which the users specified general personal data, like age, gender, or their previous experience in the field of ergonomics. Moreover, their task completion time and responses to the checklist items were stored in a database. These data were compared with those recorded in a laboratory setting, in which occupational health professionals evaluated an equivalent real-world workstation. The comparison of these two groups allowed assessing the utility of our VR scenario, the corresponding results are outlined in the evaluation section.

The WBT has been replaced, meanwhile, by our ErgoScenes platform. However, for illustrative purposes you still can access the VRML-model. For this, you need a VRML viewer, for example blaxxun Contact.