tele-education
...ART 2000, as well as videoconferencing. However, it is not limiting the network to any one technology, or suite of technologies. It is actively promoting experimentation and cooperation in the reception and delivery of courses using other software and media. Tele-education NB placed routers in the Community College Campus in each region, and other sites in regions that do not have a college. Initially it operates using 56K connections and will move T1. SMART 2000 runs not only on regular telephone lines but also on LANs and WANs using Novell, TCP-IP and other telecommunication protocols. Tele-education NB are now experimenting with synchronous transmissions using the TCP-IP protocol on NBNet. The Picturetel videoconferencing units existing in province all are CCITT compatible. Tele-education NB has provided the guidelines for selecting appropriate technology for its network as follows: „h The network shall experiment with different technologies and endeavor not to rely on any one technology or any supplier. „h Existing equipment and distance education sites in the province shall be integrated into the network wherever possible. „h The network shall establish computer teleconferencing and computer conferencing links among the sites, including access to electronic information highway and the Internet. „h Satellite delivery and reception capabilities and upgrading of sites to PC-based videoconferencing will be investigated for implementation in future. „h Other optional equipment may be placed in sites at the request of users and institutions such as MACs and CD-ROMs. „h The network should be compatible as much as possible with other provinces and regions. 3.3.2 DELTA's Virtual College Delta's Virtual College is implemented in Denmark (Europe). It offers the opportunity for students to participate in desktop Tele-education from their homes or offices. This concept means that individual students participate in Tele-educational courses using a desktop computer online connected to a course provider. The user interface is a common Web browser, that is, Netscape Web-browser, extended with loosely integrated audio and video tools. The educational environment applies the metaphor of a virtual college. The idea is that students access DELTA's virtual college server when participating in a course. The user interface looks like the plan of a college. From the college hallway, the student can enter different rooms with different functions. Those rooms are: „h classrooms where on-line lectures and presentation take place, „h group rooms where on-line cooperative work takes place, „h studies where off-line study such as self-study material, exercises, slides from previous lectures, supplementary material and links to other sites on the Web take place, „h teacher offices where it is furnished with course administration tools, „h tea room where it is used for informal chat and social contact with fellow students during break. The following figure, the "floor plan", illustrates those rooms: Figure 1 : The floor plan The goal of this virtual college is to integrate different modes of teaching and learning. This includes synchronous mode like on-line lectures and group exercises as well as asynchronous mode like interactive self study, participation and threaded bill board conferences and sharing of documents. The virtual college is run primarily in a local network environment in order easily to monitor and control the students and technology. Then, when there are several countries participate, each sites are connected by the JAMES (Joint ATM Experiment on European Services) broadband network. 3.3.3 ACTS Project AC052 (RACE Project Report) This is a big project on Tele-education. It covers the whole aspects that should be taken into consideration for implementing Tele-education in Europe such as service aspects, management aspects, network architecture, etc. In this project, there are several trials have been done in order to obtain an effective Tele-education system. The details of this will be discussed later throughout this report. 4.0 CONSIDERATIONS It is not easy to find materials or any papers reporting the architecture of Tele-education. Most of the materials found are basically discussing about the general idea on what Tele-education system is, for example some papers discuss about the general system of a Tele-education service offered, its advantages over current educational environment, etc. However, I managed to find a very interesting material discussing about Tele-education as a whole, that is the ACTS Project AC052 (RACE Report Project). Therefore, I choose this report as my main reference in doing my study on Tele-education overall system description covering the architecture. There are basically five main topics that are going to be discussed in quite detail regarding the Tele-education as a whole in this report. These main topics are: „h Tele-education service „h Tele-education content „h Network architecture of Tele-education system „h Performance of Tele-education service „h Operation and management of Tele-education service 4.1 Tele-education Service The multimedia tele-service provides both core and management services. The multimedia tele-services are briefly described as Video/audio conferencing service, which based on the MBONE (Multicast Backbone) tools VIC (video conferencing) and RAT (audio conferencing). Hypermedia service allows access to be provided to hypermedia information stored on a WWW server. The WebStore service is a managed WWW based multimedia document store, which allows users to store and retrieve arbitrary documents (text, video, audio, etc.), using the well-known interface of the WWW. The management of the WebStore includes subscription, accounting and access control. A mapping between the learning forms and the multimedia teleservices has resulted in a list of four basic paradigms: a) Self-study „h Individual work with web based course material including exercises and discovery/reference search. „h This paradigm is supported by the hypermedia and WebStore services. b) Lecture „h Teacher to class presentation. „h Supported by the conferencing and hypermedia services. c) Group work „h Discussions, exercises or project work performed by the students in groups. This paradigm can also include shared discovery/reference search. „h It is supported by conferencing, hypermedia, and WebStore services. d) Consultation „h Student to tutor consultation „h Supported by video/audio conferencing and hypermedia services. In order to support these four paradigms the multimedia services are integrated into a Tele-educational Services (TES) which provides both the core service and the management service functionality. The core Tele-educational service provides two user interfaces, one for the teacher and one for the students. In Tele-educational service, each course, presented as part of Tele-educational service, would involve the rendering and seamless integration of audio, text, graphics/bitmaps and appropriate video segments, to suit the presentation of the course material. An educational service would also facilitate the interaction of course participants with one another in class discussions, as well as with the course tutor. In this way, a course tutor can guide debates on issues arising from course material and allow participants to exchange views and share experience. This interaction is very important, as participants need to be encouraged to learn both from the tutored course as well as from each other's practical experience. This forum of discussion also supports the tutor in assessing feedback from the participants concerning the comprehension, benefit and effectiveness of a course for participants. The educational service could also facilitate access to simulation environments and 'live systems', which are parts of the participant's course material. For example, it could provide access to specific commercial database information, which would be part of a Database Modeling course. In this way, access may be gained to systems and information, which would otherwise not be available on the participant's site. Course could be taken when the participant's work schedules permitted. Similarly, participant/participant interaction could be scheduled flexibly. An educational service can be seen as incorporating several interaction (tele-services) and course presentation mechanism, for example, multimedia presentation tools conferencing, e-mail or notice board systems. The following is an example of service layer used in the ACTS Project AC052: Figure 2 : Service Layer In the ACTS Project AC052, there are two Tele-educational courses offered as a trial of the management service. These courses are " An Introduction to ATM " and " An Introduction to Relational Databases and SQL ". 4.1.1 An Introduction to ATM The course includes both synchronous and asynchronous delivery methods. The duration of the course is three to four days with approximately three hours of teaching and studying each day. The course consists of five lectures, three self study modules and three group exercises with a follow-up discussion of the results. The different modules and modes of the course are conducted in a Tele-educational environment which includes course outline information, a database of participants with pictures and CVs, a WWW billboard supporting off-line discussions, access to a WebStore and a tea-room which participants can visit for informal chats. The lectures are performed by using video/audio conference tools. A system was used to show slides on the participants web-browsers. The self study modules contained web pages with information to read and small built-in exercises. The group exercises consist of a number of questions to be answered by the group and returned to the teacher for correction afterwards. When the teacher has corrected the answers they are discussed in a conference with all the participants. In the first trial a shared editor was introduced for use in group exercises. The shared editor is a tool for synchronous collaboration on smaller texts, and is meant to complement the chat and whiteboard tools used in earlier trials. An illustration of the new shared editor can be found below. In the second trial, a new floorcontrol-system for use during lectures as well as a complete new graphical design of the virtual learning environment was tested. The floorcontrol system was used by the teacher during lectures, to determine which students wanted to ask a question, and to mute or unmute the microphones and video cameras accordingly. A new graphical design of the User Interface (UI) was introduced, in an attempt to create an even more homogenous UI. The floorplan metaphore was kept, but new images and controls where implemented throughout the environment. 4.1.2 An Introduction to Relational Databases and SQL This course covered the theoretical principles of relational database technology as well as supporting the hands-on skills of using relational database language (SQL). Students took the course over a three day period, for two hours each day. At the beginning of the course a one hour lecture outlined the objectives of the course and provided an introduction to the topics. The educational content comprised of text, graphics, and animation and was divided into four sections, consisting of a total of twenty one modules (a module typically being 1-5 pages). The course was made available via the Prospect Tele-educational environment. On accessing the course, a separate courseware browser window was opened, called the Virtual Student Desktop (VSD). All student interactions with the courseware are facilitated via this VSD. The Tele-educational environment is also accessible by the student for conferencing and synchronous interaction. The VSD is rendered as a set of WWW windows, frames, tool bar and icons. All native WWW browser buttons are suppressed (hidden) so as not to distract the user from the main goal of education. A tool bar specially designed for educational use is provided by the VSD at the bottom of the screen. From this tool bar the student is able to contact tutors or fellow students (asynchronously), access external systems, as well as navigate and interact with the educational course material. Figure 3 illustrates a page from a module in the course, and shows the educational toolbar at the bottom of the screen and an index of the topics dealt with by this particular module in the course on the left hand side of the screen. Figure 3 : page from module in the course Overall the course comprised several different types of information: Administrative (i.e. how to use the course etc.); A database of (self contained) modules; Indexes or Roadmaps of specific courses through various modules; Evaluation Forms and a Case Study. The roadmaps were important as the modules can be combined in several ways to satisfy the different requirements for different student objectives. Each roadmap corresponds to different learning objectives of the RDBMS course. Thus the roadmaps provide a means of re-using existing modules with as little redundancy as possible of educational material and administrative overhead. A significant feature of the system was to provide direct access to a real ¡¥commercial¡¦ RDBMS via the same interface as the educational course. The relational DBMS is seamlessly integrated into the student educational desktop. Thus the tool bar offered by the VSD contains an icon which allows students to issue SQL queries on a live database. The idea of this is to deliberately blur the distinction between the educational environment and the ¡¥target¡¦ systems. This encourages students to ¡¥try out¡¦ various parts of the course before attempting a larger project. Another feature was the ability of the student to store references to distinct locations in the course material (bookmarks). Traditionally these are stored locally on the student¡¦s machine. However this has disadvantages as students rarely use the same machine all the time. The VSD allows such bookmarks to be stored within the educational service and are thus (privately) accessible to an individual student at any time. Also if the student has logged off the course and logs back on, the VSD allows him/her the ability to resume at his/her most recent position or restart at the beginning. Various forms of on-line tutorials are embedded into the course. ¡¥True or False¡¦ and ¡¥Multiple Choice Questions¡¦ are supported, with automatic correction and notification of marks to the student. Form based (short unstructured text style) answers are also facilitated in some tutorials. In these cases the student answers are automatically delivered to course tutors for subsequent correction. Also integrated into the course are evaluation forms which, when completed, are automatically submitted and stored for later analysis by course tutors. The VSD provides buttons to contact other class members or to seek tutor assistance. Again, this is offered via WWW forms and integrated transparently with an email delivery system. 4.2 Tele-education Content There are several modes of educational interaction, which could be supported by a virtual theatre/study room. These would include lecture presentation, course material presentation and browsing, self-study, group work (shared application/work, class discussions, group presentations), consultation (tutor/participant, participant/participant), tutorial sessions, virtual coffee room/virtual lounge, and continuous assessment. There are also some other form of learning that have been identified. These forms of learning are: „h Self learning „h delivery of formatted courses material for students own study „h Lecture presentation „h a one-to-many presentation by the tutor of course or organizational material. „h Exercises „h the facility to perform exercises either in groups or individually „h Project work „h the development of sizeable projects using software outside the teaching environment. „h Discovery/Reference research „h ability to locate and access background or supplemental learning material „h Seminar/Class discussion groups „h many-to-many communication between participants. „h Consultation „h private one-to-one communication between participants. There is some overtap between these learning forms. For example, exercises, project work, discovery/reference search can be part of the self-learning form, but all of learning forms are listed here for completeness. It has been pointed out that not only should the different modes of teaching be supported in the Tele-educational environment but also the different styles of learning adopted by the students need to be supported. So for instance students who like to annotate their work or their course material should be facilitated in doing so. This is very much in the spirit of hypertext origins of the WWW. Another point raised is that multimedia activity in the virtual classroom should be captured and associated with relevant course material. For instance, the teachers comments on a particular slide could be captured with the slide in question. Also the conversation of students working on group could also be recorded and stored with the exercise. Course material could be presented as a hyper-document with the participant capable of navigating through the document or choosing the prescribed ordering of the presentation. In addition, the participant could also be given access to the more traditional learning material, for example, notes, books, etc. Course assignments could also be electronically submitted to promote fast feedback on performance. An important element of assignments and project work is the need to allow participants to co-operate in groups. 4.3 Network Architecture of Tele-education System From the application's point of view, network operates as IP (Internet Protocol) network routing both multicast and unicast IP packets. Connection from network level to the Q-adapters managing the switches communicate via ISO stack over X.25 links, but apart from this instances all network infrastructure is in support of IP traffic. This network structure connects seven sites. The aim of the logical network infrastructure is to provide stable network interconnections as well as to be managed to some extent by the network management, and to provide a working, broadband network infrastructure while also supporting an enterprise model suitable for multi-domain environment. For the separate customer networks, each sites posses of LANs of Ethernet, or mixed ATM/Ethernet LAN technologies. For maximum efficiency of scarce international, broadband resources, only one site in each countries (that taking part in Tele-education system) are connected. The connection, internationally connected customer sites access the public network ATM service via an ATM cross-connect (ATM XC) providing ATM public network provider's Point-of-Presence (POP) in each of relevant countries. Each customer sites posses ATM Customer Premises Equipment (CPE) which is used to interconnect ATM public network with local routers. For the connection within the same country, it is performed via leased lines between routers at internationally connected customer sites and sites not connected to ATM public network provider. The ATM CPEs at internationally connected sites and routers at all customer sites managed by VPN (Virtual Private Network) provider. It is performed in concert with management of ATM public service by VPN provider to provide Intranet style connectivity between hosts on customer site LANs. This network is quite complicated because it connects seven sites in four countries and consisting of the following core components: „h Four ATM LANs „h Seven Ethernet based LANs „h Four ATM Cross Connects „h Eight static IP routes „h Seven multicast routers „h Two 2 Mbps leased lines „h Ten International ATM links (virtual path) „h One basic rate ISDN link The following is the figure of logical network infrastructure: Figure 4 : Logical Network Infrastructure. The ATM infrastructure that represents ATM public network provider consists of a single ATM XC at each internationally connected sites. These XCs are interconnected by permanent VPs (Virtual Paths). The ATM CPE at each site based on one or more Fore System ASX-200 switches. It is employed as logically separate ATM LANs besides as providing ATM access between public network and routers at each site. The following is the figure of ATM configuration. Figure 5 : ATM Configuration. The IP configuration consists of routers at each connected sites being connected by Permanent Virtual Channel (PVC) running over VPs. The routing function at each site performed either by dedicated hardware router or by workstations running routing daemon software. Routing of multicast IP packets (used for multimedia conferencing applications) is not fully supported by most current IP routers, therefore, routing performed by multicast routing daemon (mrouteds) running on workstations. The mrouteds are interconnected by unicast IP tunnels, which can be used to be routed via routers together with all other unicast traffic. The IP tunnels between mrouted at internationally connected sites used the second sets of VPs. This supports partition of multicast traffic from other unicast traffic and thus enables provision of more deterministic Quality of Service (QoS) for multimedia conferencing application. For external infrastructure, the aim is to provide international ATM links between IP routers at the customer sites. Parallel VPs are used between each pair of sites; one for multicast routing and another one for unicast routing. Figure 6 : The network configuration Reflecting the contemporary trends in multimedia and information services, all software communication is over IP, including management system traffic. For the network infrastructures that are conducted at a single site, the requirement its network is fairly simple, requiring simply Ethernet connection to support IP communication between PCs and workstations. If the system includes the management of connections over IP switches, then the network infrastructure would include both a representative public network ATM cross connect and customer premises network ATM work-group switch (a FORE systems ASX200). These are connected and configured with multiple VPs to emulate a network with a larger number of nodes. IP routing functions in this network are provided by the SPARC workstations with ATM interface cards performing IP forwarding. The following is the network configuration of this kind of network: Figure 7 : Network configuration For this network configuration, the TES Customer is able to request the set-up of a new connection to the TES provider. The TES provider then requested the VPN provider to do likewise. The VPN provider made a request to the Public Network Provider and Customer Premises Network Provider to ensure that the end-to-end IP/ATM connection was in place for the TES Customer. This is the goal for the configuration scenario. One of the most important on an ATM network level management system is to provide end-to-end connectivity across constituent ATM network element, and so support the connectivity provisioning with fault management and quality of service features. Challenged by these requirements, a system that is able to set up ATM Virtual Paths and to correlate faulty conditions, determining how these fault effect the connectivity for each end user has been built. The following is the Network infrastructure of this system: Figure 8 : Network infrastructure The figure shows that all the network equipment is connected to one Ethernet hub, that is, the hub that acts as a backbone for one Public Network domain and two Customer Premises Networks. In reality, this hub could be partitioned into a number of internets that are inter-connected by routers, also known as the Internet. For the network that is required to operate over six sites in four different countries, would require a much more comprehensive network infrastructure. This infrastructure consisted of an ATM VP service, leased lines, and the internal ATM and IP network infrastructure. The following is the example of this network infrastructure : Figure 9 : Network infrastructure 4.4 Performance of Tele-educational Service 4.4.1 Courses There were two courses, both aimed at students with above average prior knowledge of computing and/or computer networks. The first, an introduction to SQL, was a self-study course, consisting mainly of modules of written text with assessments based on these. The second course, an introduction to ATM, was led by a tutor and involved varied methods of delivery, including lecture/seminar, individual study and group work. Students were therefore expected to interact both with one another and with the tutor. This course, too, included assessment modules. Both of the courses were offered over a three-day period and students were expected to participate for three half days. Within this time, those taking the SQL course was able to pace their own study. On the ATM course, the students¡¦ use of the different resources was timetabled and directed by the tutor. Time was divided between events, such as lectures, at which all students were expected to be present, and study time, during which they would work through a series of modules, with assessment associated with each one. 4.4.2 Students There were 16 students on the more interactive of the two courses, the Introduction to ATM, and a similar number on the self-paced study course, An Introduction to SQL. All the students appeared to be experienced computer users. This has to be accepted as necessary in a trial such as this , which takes place in the context of a research project which uses leading edge technology, some of it is still being tested. The prototypical nature of parts of the system may make unusual demands on the students, such as imposing unexpected delays. Having students who appreciate the difficulties may well be important. Having said this, it appeared that although they were knowledgeable about computers, these students were not experts in networked multimedia technology, and did need some initial training in the use of the software. This was given prior to the start of the course. The courses were clearly directed at this target group, as their titles suggest. The students also stated that they had a genuine wish to learn the subjects being offered and that this was a major motivating factor. They were also paid for their participati...