Making EJS Applications at the OSP Digital Library ... - IEEE Xplore

Making EJS Applications at the OSP Digital Library Available From Moodle Rubén Heradio, Luis de la Torre, José Sánchez, Sebastián Dormido UNED Abstract—Easy Java Simulations (EJS) is a free and open source software that allows to easily create simulations or virtual labs of very different topics such as control engineering, physics and so on. The Open Source Physics (OSP) project holds the ComPADRE library, a digital repository that offers more than 500 EJS applications, created by the community, that are accessible for free. Moodle is a free and open source software, well-known for being the most used and spread Learning Management System (LMS) all over the world. This work presents a new plugin for Moodle that allows searching, downloading, and adding to a Moodle course, EJS applications from the OSP ComPADRE library. Index Terms—Courseware, educational technology, physics education, engineering education, virtual labs.

I. INTRODUCTION It is well known that education in engineering and science disciplines requires practical experimentation. While this has been carried out in laboratories or in field for ages, the use of computers has recently introduced new approaches. Virtual laboratories (VLs), or simulations, are one of the new possibilities technology offers to cover the experimentation need in scientific and technical education programs. A VL corresponds to a computer application providing a graphical representation not only of the objects under experimentation but also of the instruments which should be used to perform the experiment in the real world. VLs are sometimes used as a complement for their hands-on laboratories practices, although this practice is still not as popular as it should or could be [1]. Thanks to their use, while students still have to perform experimental activities in a real lab, they can also spend more time experimenting from their own homes with a simulated version of the experiment. While some education courses out there only offer one of this two parts (either virtual or hands-on experimentation), it is commonly accepted that VRLs work better when both of them (the simulated experiment and its real counterpart) are offered [2]. Easy Java Simulations [3, 4] (EJS) is a tool designed for making the creation of discrete computer simulations easy and accessible to teachers that have a deep knowledge about the system they would like to simulate but lack of programming skills. Moreover, EJS makes life simpler even for teachers that have experience in programming, since it allows saving time when creating simulations because they do not need to be created from scratch. Another important thing about EJS is that it is completely free, so everybody can use it to create their own applications that suit their own needs.

EJS is part of the Open Source Physics [5, 6] project (OSP), which provides (also for free) curriculum resources that engage students in physics, computation, and computer modeling. The ComPADRE digital library of the OSP project is a network of free online resource collections supporting faculty, students, and teachers in Physic. Among these resources, users can find more than 500 applications created with EJS. These simulations can be downloaded for free from the digital library webpage [7]. Therefore, even teachers that do not have time for creating their own simulations (despite how easily and quickly EJS allows to do this) can benefit from EJS and OSP thanks to this online repository of ready-to-use applications. It is also important to highlight that the OSP digital library not only offers the EJS compiled applications but also their “source code”. This means users can open the models of the simulations with their free EJS program, examine how they are done, and easily modify them and customize them according to their own needs, tastes or desires. Moodle [8, 9] is a free and open source Course Management System (CMS), or Learning Management System (LMS); a web application that educators can use to create effective online learning sites. According to its website, Moodle has more than 73 million registered users, which makes it the most used LMS around the world. In October 2013, over 500 learning professionals from around the world shared their top ten tools for learning recently in the 7th Annual Survey of Learning Tools, organized by the Centre for Learning & Performance Technologies. Moodle came 11th in the list of Top 100 Tools for Learning 2013 [10]. Moreover, Moodle came first in the CMS category of this survey. However, despite the huge advantages and great utilities offered by the three previous tools (EJS, the OSP digital library and Moodle), there was not a way to combine the use of all of them in order to easily create online courses with virtual laboratories or simulations until now. Actually, convergence of these virtual and/or remote laboratories with LMS has been pointed out by several authors and works as one of the current issues that are not yet completely solved [11-13]. EJS allows the creation of virtual laboratories but not an easy and natural way to deploy them within a Moodle course. The OSP digital library allows downloading ready-to-use EJS applications from its webpage but the same problem arises. Moodle allows creating and managing online courses but it does not offer an option to add virtual laboratories or simulations to cover the experimentation needs of technical and scientific disciplines.

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Figure 2. Categories in the OSP digital library.

Figure 1. EJS program. EJS divides the creation of simulations in two main parts: the model (with the equations that represent the system) and the view (with the graphical user interface).

This work presents a couple of tools (two Moodle plugins or add-ons) that fix this problem by 1) joining EJS and Moodle together (the EJSApp add-on) and 2) making the EJS applications in the OSP library directly accessible from Moodle (the OSP add-on). Section II introduce these two add-ons while Section III presents UNILabs (an online web portal, based on Moodle, that offers virtual laboratories) as an example of use of these tools. II.

USE OF THE PROPOSED TOOLS & RESOURCES

A. EJS EJS is a freeware, open-source tool developed in Java, specially designed for the creation of discrete computer simulations. The architecture of EJS derives from the Model-View-Control (MVC) paradigm, whose philosophy is that interactive simulations must be composed of three parts: 1. The model describes the process under study in terms of: 1) variables, which hold the different possible states of the process, and 2) relationships between these variables, expressed by computer algorithms. 2. The view provides a graphical representation (either realistic or schematic) of the process states; i.e., the GUI of the simulation. 3. The control defines certain actions that a user can perform on the simulation. EJS makes things even simpler eliminating the “control” element of the MVC paradigm and embedding one part in the view and the other one in the model. Figure 1 shows the main window of EJS. There can be found many simulations and virtual laboratories in the literature that have been created or replicated with EJS, such as [14-36]. Therefore, a tool that allows deploying these applications into an online course such as Moodle where teachers can add additional didactic materials and values is in great demand.

B. OSP The OSP project won the Science SPORE Prize in November 2011. Among many other resources for teaching and learning, this collection offers hundreds of EJS applications and models (for example, those presented in [19-36]). Teachers can easily find those they might be interested in in two different ways: 1) by using the search function that, given a set of keywords, looks for related resources and 2) browsing these resources navigating through the different categories in which they are organized. Both options can be seen in Figure 2. In both cases, files (either the EJS compiled application or the EJS source code) are downloaded to the user’s computer, waiting to be used, modified or redeployed. C. Moodle Simulations, virtual and/or remote laboratories do not provide by themselves all the convenient resources for a complete online course. In the context of this kind of course, students must carry out their practical activities in an autonomous way. Therefore, if teachers want to facilitate their work, complementary web–based resources to the virtual and/or remote laboratories should be included. For this reason, for each simulation, virtual and/or remote laboratory there should be available, not only a description of the phenomena under, but also the tasks protocol that students must follow to achieve the proposed goals while working with the lab application. Moreover, in order to assess the students’ progression, they should prepare a lab report with the data collected during the simulated and real experimentation that the instructors can correct. Moodle is a widespread LMS that can be customized to support such features. III. MOODLE ADD-ONS The “M” in Moodle stands for modular. The easiest and most maintainable way to add new functionalities to Moodle is by creating a plugin or add-on. There are more than 600 add-ons for Moodle listed in its webpage, all of them also available for free. Since all the tools and/or resources in which this work is based on are free (EJS, OSP and Moodle), it was important for the authors to offer the solution that joins all these things together also for free. Therefore, Moodle add-ons are the perfect way to achieve this objective.


Figure 4. EJSApp form to add a new simulation/lab activity in Moodle.

Figure 3. EJSApp form to set access conditions to a simulation/lab activity in Moodle.

A. The EJSApp add-on To support the one-click deployment of virtual and/or remote laboratories into Moodle, we have developed the EJSApp plugin [37]. The EJSApp module supports: 1. Deploying virtual and/or remote laboratories written in EJS. Figure 3 shows the form EJSApp provides to add a simulation/lab to Moodle. EJSApp supports the integration into Moodle of any kind of application developed with EJS. EJSApp uses the new Moodle 2 feature File Picker, enabling virtual laboratories to be uploaded not only from the user computer but also from a variety of repositories such as Dropbox, Alfresco, etc. 2. Controlling user access to the deployed labs. EJSApp supports setting the start and end dates when a virtual and/or remote lab will be accessible to the students, the minimum grade students need to get in other activities as a previous condition before having access to the lab, etc. Figure 4 shows the form EJSApp provides to set these conditions. 3. Backup and restore. EJSApp provides maintenance facilities for the lab applications, packaging them into Moodle standard course backups. 4. Supervision and statistics. Access from Moodle users to EJSApp activities are recorded and can be

used for performing statistics and supervising the time students spend working in each lab. The EJSApp add-on is listed as one of the more than 600 approved add-ons for Moodle and can be downloaded from the Moodle official webpage at: https://moodle.org/plugins/view.php?plugin=mod_ejsapp. EJSApp received the Moodle Hat Award on December 2012, just a few days after it was first released. This award is given by the Moodle staff and only 18 add-ons have received it by November 2013. Considering the number of existing add-ons up to this date, this means that only a 3% of these add-ons get to receive this award. Finally, another indicator of the high quality and/or utility of this tool is that it has been downloaded more than 1200 times in less than a year. UNEDLabs [37, 38] (a network of virtual and remote laboratories) was created based on the use of EJS, Moodle and this add-on. UNEDLabs has been operative for two years, allowing students of several different universities (such as UNED or the University of Almería) to perform their experimental activities in an online and remote way. By combining the use of EJSApp and EJS, a teacher could create a simulation with EJS, compile it into a java applet and then deploy it to a Moodle course with no effort using EJSApp. By combining the use of EJSApp and the OSP digital library, a teacher could visit the OSP webpage, browse existing EJS simulations, download one she is interested in to her computer, and then deploy it to her own Moodle course by picking it from her computer once it has been downloaded. By combining the use of EJSApp, EJS and the OSP digital library, a techer could download an already existing EJS simulation, open it with EJS, customize it according her own tastes or needs and then deploy it to a Moodle course. Still, the previous tools still have a limitation since they do not allow users to directly search EJS simulations in the OSP digital library from Moodle and adding them to the online course. Instead, they first have to go to the OSP webpage, download the application to their own computer, then go to their Moodle course and upload the simulation from their hard disk. This is where the OSP add-on goes into action. B. The OSP add-on The OSP add-on (also available for free from the Moodle website), allows Moodle users to connect their File Picker with the OSP digital library, in a similar way as the connection to Dropbox, Alfresco or Youtube from this tool works. The advantages for Moodle users are: 1) they never need to leave the Moodle environment when adding/reorganizing the simulation activities in their online courses and 2) they do not need to download the simulation file from OSP to their computer and then upload it to their Moodle server; instead, the file passes directly from OSP to their Moodle server. Therefore, this tool provides teachers with a very fast and easy way to search, select and deploy simulations or virtual laboratories already created by the EJS community and available at the OSP repository. Figure 5 shows a screenshot of the OSP add-on for Moodle when the keyword “circuit” has been used to make a search for related simulations. Results show one image for each


mathematics. The secret of the fast growing of UNILabs is, of course, its web 2.0 features, extended now to the addition of simulations, virtual and/or remote laboratories thanks to the EJSApp and the OSP add-ons. This way, each teacher in UNILabs has editing rights over their own courses and therefore, any of them can add, in an easy and an autonomous way, the experimentation resources they need for their courses and subjects. Figure 6 shows UNILabs’ homepage. More information about the EJSApp and OSP add-ons and the old UNEDLabs portal can be found in video format at our youtube channel: http://www.youtube.com/user/UNEDLabs. REFERENCES [1]

[2] Figure 5. OSP add-on for Moodle.

simulation as well as their name. If the user places the mouse over one of them, a description of the application appears (see third simulation at the top row in Figure 5). IV. EXAMPLE OF USE - UNILABS UNILabs (http://unilabs.dia.uned.es) is the evolution of UNEDLabs. UNILabs uses the latest version of both Moodle and the EJSApp plugin, it incorporates the new OSP plugin, and it involves more universities in its network than UNEDLabs. UNILabs was born on September 2013 and by November 2013 it already offers six courses with virtual and/or remote laboratories and covering topics such as automatic control, physics or

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Figure 6. UNILabs frontpage.


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