advanced web technology for e-sessions of video

ADVANCED WEB TECHNOLOGY FOR E-SESSIONS OF VIDEOCONFERENCE IN COLLABORATIVE WORK ENVIRONMENTS Valentin Pupezescu1, Radu Rădescu1, Sever Paşca1 1

Polytechnic University of Bucharest, Faculty of Electronics, Telecommunications and Information Technology, Applied Electronics and Information Engineering Department (ROMANIA)

Abstract This paper proposes a web server architecture that contains an open-source e-learning platform dedicated to asynchronous activity and a platform dedicated to organizing webinars (Internet held seminars). It is also proposed a Google Apps implementation, using the web application suite offered by Google: Gmail, Google Docs, and Google Calendar. Gmail application runs in its own web server, providing local email addresses. The Google Apps set allows each actor involved in using the application to have its own email address on which integrated chat and documents editing into collaborative e-work systems are used. The WebMeeting platform is available for free for up to 200 participants, and the costs of implementing the system are relatively low. Keywords: Adaptive e-learning, Virtual class, Multimedia streaming, E-courses, Webinars, WebMeeting, Web technologies, Technology-enhanced learning, Open-source platforms.

1

INTRODUCTION

Data transmission technologies have experienced great development in recent years [1]. The level of broadband penetration in Romania exceeds 45% of the total population (June 2016). Almost all Internet-connected computers are equipped with webcams and microphones, which can play video and audio smoothly. So the ground is prepared for a revolution in virtual learning. This paper demonstrates that implementing video-conference sessions with multimedia elements in an e-learning platform requires basic technical knowledge and accessible hardware. Platform dedicated to virtual courses, like Moodle, Claroline, Docebo, etc., are extensively used worldwide. Moodle can be installed for free and allows the formation of e-classes by posting various documents related to subjects taught and organizing testing of students. Basically, through this application conventional teaching activities are transitioned into a virtual environment. All these activities, except one, make contact (more or less) directly with students. In this regard, the Dimdim WebMeeting [2] application dedicated to video-conferencing on Internet is used. The application provides whiteboard, screen-casting ability and URL-sharing, but also the possibility to upload PDF or PPT files and virtual presentations. Moreover, up to 3 webcam and 5 microphone slots are available in order to facilitate communication between participants.

2

MOODLE IMPLEMENTATION

The minimum requirements of a system to support all of the above applications are:  single-core processor, 1-2 GB RAM, Linux OS (CentOS, preferably ver. 5 or higher);  Apache web server, MySQL DBMS, PHP interpreter;  SSH access or directly from a terminal with root access. Such systems can be found routinely in most academic or can be rented from hosting companies, at prices ranging between 20 and 50 EUR. Installing Moodle is conducted like modern desktop applications. From http://download.moodle.org address one can download the latest version of the application. Archive content is copied to the root of the web server (usually, /var/www/html/) and creates a new MySQL database that will be used to store data. It then accesses the web server (directly on the domain name or IP address, if not associated with a domain name) and follows the steps of a procedure (wizard) installation. The application can be customized with different graphic themes available for free on the Internet and managed by an administrative username created during wizard process.

Next steps are to create accounts for teachers and students, and putting into production the application. The average time for the installation of such a platform is 0.5-2 hours. The time required to customization and creation of users varies by institution, but all activities are carried out through graphical management interface.

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DIMDIM WEBMEETING

At the time of writing this paper, open-source version of Dimdim WebMeeting technology was offered in three versions: RPM for CentOS, source code, and VMware virtual machine image. Regardless of the casing embodiment, the platform has the architecture of Figure 1.

Figure 1. The Dimdim WebMeeting architecture [2] Streaming is done based on Flash technology, by using a free Flash Media Server, called Red5. Data is transmitted via RTMP (Real Time Media Protocol) and can be accessed for registration based on separate URLs for each conference session. Components that do not take application streaming (public and private chat, application interface and admin panel) are implemented using Java Servlets and served to customers using Apache Tomcat Web Server. Because the server will have two active web servers simultaneously (one responsible for Moodle and the one responsible for Dimdim), Dimdim is set up to run on a different port than the default HTTP protocol, namely, 80. Configuring is done by running a script, the whole procedure being documented in a text file that came with the application. For document management, the application uses a series of OpenOffice SDK libraries and some Python libraries (also used for inter-component communication). The installation of these libraries is made before running the RPM package or compiling the source code. Obtaining and installing these packages is fully documented in the accompanying package file downloaded from dimdim.com. The Dimdim Data server is composed of a number of components responsible for various functional units, using two levels of interaction protocols.

The first level is called End User Protocol Suite (EUPS) and is running over HTTP. This level is designed to communicate with Dimdim users. The only protocol not running on HTTP is responsible for the webcast and the whiteboard communication. This protocol is RTMP (Real Time Media Protocol) and uses the 1935 TCP port. The second set of protocols for communicating between components and is called Dimdim ICoPS (Inter Component Protocol Suite). Dimdim infrastructure [2] is located behind an nginx server, which handles transparent access to the application. WMI's main components are:  Dimdim Conference Server;  Dimdim Media Server;  Dimdim Screenshare Server (Spotlight);  Dimdim Streaming Server. These components are accessed through an nxginx reverse-proxy and thus are externally visible in a single HTTP access point, differentiation being made through the interpretation of URLs. This reduces the complexity of architecture ports and makes easier to maintain a policy firewall installation.

4

DIMDIM WEBMEETING COMPONENTS

Dimdim Conference Server (DCS) is a pub/sub system having the role to provide the infrastructure that enables conferences to interact using a messaging system responsible for the states and participants management. DCS works with the external JSON protocol transmitted over HTTP/HTTPS. Dimdim Media Server (DMS) is responsible for organizing different types of media resources, such as PowerPoint presentations, PDF files, etc. Dimdim Screenshare Server (Reflector) is a scalable protocol that enables the presenter's screen distribution to participants. Basically, Reflector is a modified VNC service that is transmitted using HTTP/HTTPS via FastCGI technology. The service supports multiple screens, each with multiple presenters and participants. Dimdim Streaming Media Server (DSMS) provides capabilities for audio and video streaming, and whiteboard, those using the RTMP protocol. Dimdim server implementation of this service is based on Red5 Flash Media Server, an open-source alternative to Adobe Flash Media Server, which involves a huge licensing cost. Architecture ports. One of the main goals in designing Dimdim was decreasing the number of ports required to be opened on server firewall. Because the nginx web server has very well developed reverse proxy capabilities, it is possible to have a single HTTP port open. It is recommended that port 1935 is open too in the firewall for RTMP direct access. The remaining ports used by Dimdim are internally accessed by the various functional units, so there is no need to be open to the public.

5

GOOGLE APPS

Google Apps is a set of tools for companies and academia. Its implementation is done by creating an administrator account on http://google.com/apps. After creation, a subdomain account is created on the server to redirect traffic to http://google.com/a/domain_name and create the initial set of users. To activate the service by email, a set of MX records is inserted in the admin panel of local email server. Internet addresses are provided by Google at registration process. After performing these installation steps (see Figure 2), users have access to:  Gmail email services, with storage capacity of up to 7 GB.  Google Docs, a set of web-based office applications [3]. Text files, spreadsheets or presentations can be edited here. Editing can be done collaboratively, document creator being able to specify access rights of each user or group of users.  Google Calendar, a PIM (Personal Information Management) application that enables SMS alerts synchronization with local applications like MS Outlook or with PDAs.

Figure 2. Starting a Dimdim WebMeeting conference session

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DIMDIM WEBMEETING ADVANTAGES

This system has introduced a wide range of applicability, in both corporate and academia environments. Basically any university could open doors to WebMeeting sessions in distance education with low-cost installation. Basically, any universities can open doors to Dimdim WebMeeting sessions in distance education, with the following costs:  server – starting at 50 EUR/month;  .com domain - approx. 40 EUR;  software installation – starting from 100-200 EUR, one can find specialized staff to implement the software package (a good resource for doing this is getafreelancer.com). Once implemented, as we did at the Polytechnic University of Bucharest, Faculty of Electronics, Telecommunications and Information Technology, Applied Electronics and Information Engineering Department [4], using the Easy-Learning online platform [5], [6], [7], [8], the application can be used for providing services to students in any university. Web conferencing platforms can be integrated with any web application via an URL-based API (Application Programming Interface). This way, web conferences can be configured and generated and user access links can be created. The collaborative documents editing can streamline e-teaching involving teams (e.g., research papers, term projects, graduation works, etc.). The video-conference platform can be used for organizing students' scientific sessions or training with remote lecturers, especially from abroad (see Figure 3).

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CONCLUSIONS

The present work proposed a web server architecture that contains an open-source e-learning platform dedicated to asynchronous activity and a platform dedicated to organizing webinars (Internet held seminars). It is also proposed a Google Apps implementation, using the web application suite offered by Google: Gmail, Google Docs, and Google Calendar. Using Dimdim WebMeeting video-conferences, tutors can plan counseling e-sessions in collaborative work environments or inter-departmental e-meetings. Various events held in the university campus can be live broadcasted on the Internet, for free or for a fee, thus creating a possible new financial influx channel. Moreover, tutors can provide course material on a single platform, while creating a virtual library freely accessible to all students. This paper showed that implementing video-conference sessions with multimedia components in an elearning environment is easy to do and requires minimal technical knowledge and low-cost infrastructure.

Figure 3. The lecturer's window in a Dimdim WebMeeting e-session of a video-conference

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European Commission report on telecommunications: Eight Member States have exceeded the US market for broadband telecommunications, available at: http://europa.eu/rapid/pressReleasesAction.do?reference=IP/08/460&format=PDF&aged=1&lan guage=RO&guiLanguage=en

[2]

Dimdim download: https://sourceforge.net/projects/dimdim/files/Dimdim%20v4.5%20Release/

[3]

Google Docs, available at: http://docs.google.com/support/bin/answer.py?hl=en&answer=134592

[4]

A. Marinescu, scientific coordinator R. Rădescu, “Implementing a video-conference application for e-learning systems”, graduation thesis, University „Politehnica” of Bucharest, July 2009.

[5]

R. Rădescu, “E-learning: concept, implementing and applications”, IT&C Market Watch, Fin Watch, Bucharest, No. 30/2004, p. 50, No. 31/2004, p. 61, No. 33/2004, p. 50 (series).

[6]

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