WebLab Module for the Moodle Learning Management System Ľ. Čirka, M. Kvasnica, and M. Fikar Slovak University of Technology in Bratislava Faculty of Chemical and Food Technology
[email protected] Abstract
experiments are primarily to be used in studies oriented on automation, control, and industrial informatics.
This paper is concerned with the WebLab module for the Moodle Learning Management System (LMS). In short, WebLab allows users to remotely access distant laboratory experiments using a web browser. To prevent clashes when multiple users try to access the same experiment at the same time, the module allows to book the experiment in advance for a chosen period of time. In addition, WebLab allows custom control strategies to be uploaded by the user to operate the experiment in different ways. To do this, the module provides the users with the option to upload additional MATLAB/Simulink files to the central web-server. These files are first checked for the presence of forbidden actions (such as commands for deleting system files), and are subsequently downloaded directly to the experimental setup where they are executed.
1. Introduction
Fig. 1. Thermo-Optical Laboratory Plant
The Moodle LMS [4] was chosen as an integrating platform for this process due to its modular design. In addition, Moodle is available under a free, open-source license. This allows basically anyone to extend its functionality by developing custom modules. As of now, Moodle is being used by several faculties of the Slovak University of Technology (STU) in Bratislava, Slovakia as a tool for creating on-line versions of courses being lectured. The on-line courses provide students with easy access to teaching materials, such as lecture slides and online tests. Motivated by the success of an on-line versions of the Process Modelling and Process Control courses on the Faculty of chemical and food technology at STU, we have decided to further extend the functionality by creating a new module for accessing experiments in a remote fashion. As of now, the laboratories offer access to two types of experiments: a thermo-optical system and a hydraulic laboratory plant. The practical setup of these systems is depicted in Fig. 1. Both laboratory plants are aimed to increase the students' knowledge in areas of input-output data manipulation, computer-to-plant communication techniques, experimental system identification, and control design techniques. Hence, these
Fig. 1. Hydraulic Plant The experimental plants include their own microprocessors for data processing and communication, which allow for easy connection to a standard PC running
MATLAB/Simulink using an USB port. This eliminates the need to install custom hardware input/cards and/or special real-time control software. In Simulink, each plant is represented by a single block, which can be coupled to a custom control strategy.
during weekends (for instance due to security reasons), we can simply disable the Sat and Sun columns of the table, which correspond, respectively, to Saturdays and Sundays. This setting will disallow access to the device during all weekends of the 13 week long activity.
2. WebLab module
Clicking the Continue button the activity creation will complete.
The WebLab module is implemented in the Moodle LMS as an Activity plug-in and it allows users to perform various tasks, depending on their credentials. The objective of the module is to provide the booking functionality. From a technical perspective, this procedure is implemented as a Java applet executed in the user's browser which communicates with another Java application running on the server, which in turn collects data directly from the experiment itself.
2.1. Module installation To install and use module WebLab, unzip the zip file (weblab.zip) to directory mod within your Moodle root directory (/mod/). In addition, copy the file /mod/weblab/lang/weblab.php into your /lang/en_utf/ directory (Moodle 1.9). Afterwards, visit your admin screen to finish installation.
2.2. Device installation
Fig. 3. Adding a new activity – WebLab
Configuration of device is defined in a separate subdirectory devices/ and consists of the following mandatory elements: • •
config.php: parameters of the Java applet and the FTP server Java applet (filename with the .jar extension) and its accompanying files
Note: It is recommended to use digits as names of individual directories ().
2.3. Activity creation Once the WebLab module and the device are both installed properly, the module is then available in the „Add an Activity...“ list. Selecting this activity will open a new window which will allow to define the name of the activity and its description (see Fig. 3a). In addition, it is necessary to define the Start and End dates (Fig. 3b), which specifies a time range during which the device is accessible. Finally, the device to control is selected from the list (Fig. 3c). Following the Next option it is possible to exclude certain time intervals, or even whole days, from the list (Fig. 4). For instance, if we want to disable access to the device
Fig. 4. Time constraints for device
2.4. Device booking If the device is available, it will be marked by the word Free (Fig. 5) in the respective cells of the table. By clicking the Free link a respective booking will be performed. Subsequently, the cell will change its contents to Reserved (number), where the number represents an ID of the user which booked the experiment for her/his needs. Name of the user can be displayed by placing the mouse cursor over the link. Another click on the Reserve link will cancel the booking.
Clicking this button will activate a JAVA applet [1], which allows to communicate with the device and perform live experiments (Fig. 8). The precondition for successful execution of the applet is that all necessary files must be properly uploaded to the server.
Fig. 6. List of bookings
Fig. 5. Booking table If the device is booked, a new table will be displayed which shows the list of all bookings in WebLab for the currently logged-in user (Fig. 6). Fig. 7. File upload form WebLab allows users to upload custom files used for operating the laboratory devices. These can be e.g. Simulink control schemes and/or auxiliary dataprocessing m-files. The files can be uploaded by clicking the “Upload files” button (Fig. 7). Number of the uploaded files is unlimited.
2.5. Roles in WebLab If the user is logged in as a teacher, he/she can: •
Note: Only three files at a time can be uploaded. However, the user can repeat the upload procedure as many times as desired. Once the actual time coincides with the booking time, the “Show device” button will appear on the web page.
• •
Create a time schedule indicating on which hours of a work-week a given experiment can be used. Cancel the booking for a single user. Review all placed bookings
If the user is logged in as a student, he/she can:
• • •
Book of the plant for his/her experiment and to cancel the booking Upload custom control strategies and additional files for the MATLAB/Simulink environment Review the archive of his/her bookings
modules which we have developed earlier ([2], [3]). Further development of WebLab will focus on issues of time synchronization between the web server and the FTP server, as well as adding support for more advanced configuration of the bookings. Acknowledgments The authors are pleased to acknowledge the financial support of the Scientific Grant Agency of the Slovak Republic under the grants 1/3081/06, 1/4055/07, and of the Agency for Support of Research and Development under the grant APVV 0027-07.
4. References [1] P. Bisták, M. Beránek, Java Client Server Applications for Remote Laboratory Based on Matlab and COM. In Proceedings of 7th International Conference Virtual University, Bratislava, pp. 135–139, 2006. [2] Ľ. Čirka and M. Fikar, Registration – an Activity Module for LMS Moodle. In Proceedings of 7th International Conference Virtual University, Bratislava, pp. 184–187, 2006. [3] Ľ. Čirka and M. Fikar, LMS Moodle – Random Assignment. In Proceedings of 8th International Conference Virtual University, Bratislava, pp. 168–170, 2007. Fig. 8. Java applet
3. Conclusions The presented WebLab module is currently in a testing phase. After the testing completes, it will be publicly accessible via the official Moodle page, similarly to other
[4] Moodle. Moodle-a free, open source course management system for online learning, {on-line, 2008}. http://moodle.org.
