Modern information technologies are transforming the way people learn. E-learning provides new possibilities for personalized learning at home or in the workplace, reduces the need for costly classroom training, and enables an optimal balance between tradi
for only one course. By assuming that course data, esp. in computer science, changes very fast, costs for updating will occur. Other possibilities for content creation are the specific application development (e.g. Java applets for web-use) or the use of multimedia production tools (e.g. Multimedia Toolbox [7]), Macromedia Flash [8]. But these solutions all have one thing in common: \textit{high costs}. To avoid such high costs, systems for the creation of electronic course content during a normal lecture were developed. TTT [9] and AOF [10] are examples for this approach. The big advantage of those systems are the reduced costs for the creation of electronic course content. As we discussed in the sections before, a very important feature of e-learning systems should be the easy practibility. When analyzing those two tools for this important requirement, we see that it is not easy for operators or students to produce or access the electronic content. In field experiments we determined that the programs restricted users in various ways. The most important restriction was the need of installing special programs to access the content. In the case of TTT also JAVA and JMF had to be installed. Even computer science students were not able to do so.2.2 Online Lecturing NeedsAs described in the previous section, past teleteaching systems limit operators and users to various ways. On operator' side the lecturer is often rigidly bound to an operating system or to necessary bandwidths. Also s widely spread is the restriction in using special presentation systems [9,10], e.g. PowerPoint, which finally leads to the lecturer' degradation to a slide commentator. Today, a good lecture should contain dynamic s contents, such as animations and demonstration programs, as well as arbitrary information from the WWW. An unrestricted use of all usual operating systems is also desirable. On the users' side, students and other interested persons, who want to retrieve courses via the Internet, should not be subjected to the torture of complicated installation and operating steps. In the winter semester 2001/2002 for the first time teleteaching systems [9] were tested and used at the local chair. All applied systems were very difficult to install and to use, due to the need for Java or other software packages. In addition, a lot of programs were very instable. The experience showed that even computer science students were not able to furnish and operate such special software packages correctly. Proceeding from these observations, we improved the development of a less limited, better applicable and at the same time more efficient teleteaching software system. Apart from the requirement of easy to use, a transmission of the lecture should be possible down at the modem speed, since not every student has a wide-band Internet connection. The use of standards, the permission of any operating system and any presentation software are also required for the development of a new teleteaching system. The following list shows the requirements of a modern tele-lecturing system in order of their importance: Complete mapping of the classroom situation (Beamer, Video, Voice) Simple usage for the student. Most desired is: o Use of standard pre-installed software o Platform independency item Simple usage for lecturer. Most desired is o "One-Push-Buttom" technology o Integrated all in one solution o Usage of own euquipement (e.g. Laptop) o Web integratable Modem speed is enough for a transmission Online (live, on-demand) and Offline (CD,DVD, Download) capable At the University of Trier, at the chair "Theoretical concepts and new applications in computer science", a new teleteaching concept has been developed and tested, which grants an entrance to on-line lectures in the simplest possible way and breaks down the barriers for producing and accessing distance learning content. Tele-TASK represents itself as a result of these considerations and developments. The experiences in the field use in the summer semester 2002, the reactions of the users and the high access numbers confirm the quality of our concept.
Modern information technologies are transforming the way people learn. E-learning provides new possibilities for personalized learning at home or in the workplace, reduces the need for costly classroom training, and enables an optimal balance between tradi
2.3 tele-TASK Content CreationBased on the above considerations, we thought about electronic content creation with the needs of online lecturing and the reduction of the traditional costs in mind. Our basic idea is, to use the original lecture to produce e-learning content on the fly. But the most important requirement was the easy use for operators and end-users. The complete classroom situation including the desktop of the presenters computer, the video and the audio should be mapped into electronic course material. We desire to transfer the complete course live and on-demand to the internet. Also for offline usage, the course data should be saved. Figure 1 shows the structure of the tele-task system.Figure 1: Structure of tele-TASK In the following we show the different parts of the system.2.3.1 Transmission of the desktopVarious online lecturing systems (see Real [11], Microsoft [12], AOF [10], ...) have to run on the presenter’s computer. In these cases special requirement are claimed to the presenter’s computer. Often, those solutions call for special operation systems, special presentation software or high CPU power. In the case of non computer science lectures this presents a big problem. Most lecturers are unwilling to install anything new on their computer, or they do not have permission to do so. The solution is to deliver the desktop to another computer. This transmission is done with VNC [13]. VNC allows to transfer a desktop, no matter which operation system, to another computer without the loss of quality. To reduce the bandwidth we are using tightVNC [14] which transfers less packets than original VNC and it also compresses the packets. On the encoding machine, the desktop is processed further more.2.3.2 Capturing Video and Audiotele-TASK supports two different ways of accessing videos. The first solution is to use a video device connected directly to the encoding machine. By using the Microsoft DirectX library [15], we can access any video device connected to the encoding machine. This could be e.g. a cheap webcam, an analog video camcorder or firewire videocamera. The system supports multiple video devices which could be switched during the recording. Video resolution can be set up for each device seperately. Audio can be delivered via Firewire over the videocamera to the encoding machine, or by the anolog or digital audio input. The second way of transfering the video is to send it over the network. tele-TASK provides a tool for transmitting and receiving video and audio over the network. In those cases, the encoding machine can be set up in different locations.2.3.3 Synchronisation of the streamsThe encoder consumes altogether three streams (video, audio and desktop). The developed tele-TASK software package combines the three input streams. Figure 2 shows an example for the arrangement of 4 Streams (Video, Audio, Desktop and Table of Content). The arrow shows the coherence between the video