Life to OpenSim [7] as the choice of virtual world platform. Two case studies are presented of moving from 2D web- based learning environments to 3D versions: ...
Session T2E
The Third Dimension in Open Learning Colin Allison, Alan Miller, Thomas Sturgeon, Indika Perera and John McCaffrey University of St Andrews, {ca, alan, tommy, indika, jm726}@cs.st-andrews.ac.uk Abstract - Virtual worlds continue to attract considerable interest as an innovative means of engaging students through the use of immersive, collaborative environments. They allow for the dynamic creation of content and for that content to be programmed. They empower students to explore learning environments that would be inaccessible to them in the real world. Learners achieve presence through the proxies of avatars, and consequently are aware of and may interact with fellow learners within the virtual environment. Interactivity ranges from simple exhibits as might be found in a museum to configurable, complex simulations rendered in a 3D space. At the same time there are now numerous open learning initiatives which seek to encourage the sharing of independently produced educational resources through the Internet, but these are mostly web-based, so the challenge of producing open learning materials based on virtual worlds remains. This paper identifies the challenges which need to be met to support the use of virtual world technologies in the emerging open learning context and presents two case studies of moving from 2D web-based learning environments to 3D virtual world versions of the same topic. These examples illustrate the type of innovative 3D learning environments that can be shared in the open learning context. Index Terms Virtual Worlds, Open Learning, Computer Networking Education INTRODUCTION The evolution of online learning environments can be characterized variously as single-user or multi-user, programmable or ready-made, static or dynamic, commercial or open source, and 1D or 2D or 3D. These sets of characteristics are largely orthogonal to each other. For example, the PLATO (Programmed Logic for Automated Teaching Operations) system, which dates from the early 1960s, provided interaction that can be characterized as one dimensional as it was based on simple teletype style terminal command line. At the same time it also provided multi-user user facilities via application concepts such as message boards, chat rooms and forums. In contrast the UNIX Learn program [1] featured one dimensional interaction but was strictly single user. The advent of the web saw a dramatic growth in what can be characterized as 2D online learning resources i.e. interaction is via WIMP1 style interfaces sometimes 1
WIMP: Windows, Icons, Menus and Pointers
augmented with multimedia such as audio and video. In some cases multi-user facilities are provided which are 2D versions of application concepts such as the message boards, chat rooms and forums that were piloted by participants using command line systems. The “Web 2” impetus to facilitate user-generated content and sharing of ideas has further enhanced 2D learning environments with facilities such as tag clouds and social bookmarks. Against the current computer-based learning landscape two concepts have recently emerged: open learning and virtual worlds, which are quite distant from each other. It is suggested in this paper that they can usefully be brought together. Two case studies are presented of moving from 2D to 3D online learning environments, in such a way that the 3D versions can be shared as single transferrable archive files. The motivation for exploiting virtual worlds for education is that students are readily engaged by the experience and potential of the technology. In Perera et al [2], where Second Life was used as the basis for credit-bearing coursework, it was observed that students spent much more time and effort on their practical work than the amount of credit warranted. Furthermore the quality of work produced attracted a higher than average number of distinctions and near distinctions. In the wider context of public engagement with science we note that NASA has adopted virtual world technology for a variety of educational purposes [3]. Table 1 summarizes some of the key characteristics that are needed to support 3D open learning resource development. For the purposes of open learning we are particularly interested in open source, non-commercial, programmable learning environments. Until now, Second Life (SL) [4] has been the dominant virtual world technology in use in education [5], and whilst attractive in that it is a ready-made - albeit commercial - service, it was not designed for open educational use and has significant social, economic and technical drawbacks when used for that purpose. These drawbacks have been documented in [6] and include: commercial cost, limited programmability, restricted program resource usage, severely restricted backup, copy and sharing of content (including one’s own), limited communication with facilities outside of the virtual world, the inappropriate presence of “adult content”, age restrictions that can cut across higher education classes, and the difficulty of management of user ids and credit-bearing coursework. On the other hand it could be argued that the single global world provided by Second Life is a convenient means of sharing learning environments, as access to SL is free, and the creator of a learning resource can choose to allow “public access”. However, in addition to all the
978-1-61284-469-5/11/$26.00 ©2011 Crown October 12 - 15, 2011, Rapid City, SD 41st ASEE/IEEE Frontiers in Education Conference T2E-1
Session T2E drawbacks previously listed the centralized nature of the Second Life service also means that there can be issues of quality of experience due to varying network conditions and server loads. TABLE I CHARACTERISTICS OF 1D, 2D AND 3D LEARNING ENVIRONMENT PLATFORMS
Ready made Fully Programm able Single User Multi-user Commercial Open Source Ease of content copy
1D Command Line based
2D Web based
x
3D Open Sim based
Second Life based
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
As shown in Table 1, OpenSim has a more appropriate set of characteristics than Second Life for 3D open learning. In particular, a learning environment created in OpenSim can be saved as a single OAR (OpenSim Archive) file, that can be copied and shared via any file-based open learning repository. It is noteworthy that NASA moved from Second Life to OpenSim [7] as the choice of virtual world platform. Two case studies are presented of moving from 2D webbased learning environments to 3D versions: Internet routing algorithms (OSPF) and IEEE 802.11 (WiFi) protocols. In both cases the OpenSim open source virtual world framework is used. The relative power of using OpenSim is highlighted when compared with Second Life, and crucially, the ability to distribute, share and re-use 3D educational content is supported. COMPUTER NETWORKING EDUCATION Computer Networks are an example of a topic area where online learning resources can make a significant contribution towards effective and efficient exploratory learning. Books are a vital and respected resource in networking education, as is evidenced by the frequent revisions to popular publications such as [8-10] ([11] has issued 5 editions over the last 10 years). At the same time, books have limits in what they can convey, and in how many students they can engage. Not all students engage well with the static presentations of text books. This is in part
due to the invisibility of networks in action. Packets travel at fractions of a microsecond, and networking hardware is usually a rack-mounted box with flashing lights and many cables attached. The opacity of networks in action can act as a deterrent to engagement. Complementing textbooks with 2D interactive animated diagrams is an obvious step to take and many popular textbooks now include a CD or a web site link to provide complementary animated material. For example, the TCP state transition diagram, which is featured in many books, has been turned into an interactive learning resource by the TCP View web site [12]. Learners can choose which state transitions to study and can filter these by client or server views. TCP Live [13] developed this type of approach further by allowing learners to analyse real TCP traces, that they may have created themselves, to see how a particular segment relates to the TCP state transition diagram. The expansion of types of learning resources results in a wider accommodation of learning modes and these can help students who would otherwise lose interest and struggle. They can provide an extra degree of engagement in the crowded curriculum. In [14] a study of exam results across two academic years suggested that students who were weaker academically across all their subjects benefited and improved their grades significantly for 802.11 exam questions after being given access to the web-based WiFi Virtual Laboratory. The WiFiVL site [15] contains two types of resources: informational, interactive animations and simple simulations, and a user friendly web interface to the ns2 simulator [16]. A similar site was also created to support teaching and learning OSPF routing [17], albeit without a simulator component. In order to investigate the suitability of virtual world technologies for open learning we have taken two topics already well supported in 2D Web sites – 802.11 and OSPF - as the subjects for multi-user 3D learning environments. In terms of the taxonomy given in Table 1 the WiFiVL and OSPF-Learn appear as readymade, single user, open access 2D learning environments to students. They have been programmed and deployed using several open source, free-to-use-for-education technologies including Java, Javascript, Apache, Tomcat, ns2 and xhtml. The next two sections report on the evolution of WiFiVL and OSPF-Learn to 3D Open Learning resources. WIRELESS ISLAND The original development and deployment of WiFiVL is reported in [15]. One of the basic aims was to allow students to access the power of the ns2 simulator in order to create, run and visualize 802.11 scenarios without having to take the time to learn the Object TCL [18] extensions needed for the “native” programming of ns2. In other words, it provided a degree of usability that allowed students to focus on the subject domain, rather than on simulator programming. WiFiVL provides entirely web-based interfaces for scenario setup and graphical playback. In addition the web site also provides interactive animations of the type that often accompany networking textbooks. For
978-1-61284-469-5/11/$26.00 ©2011 Crown October 12 - 15, 2011, Rapid City, SD 41st ASEE/IEEE Frontiers in Education Conference T2E-2
Session T2E example, Fig. 2 shows a still from a user-controlled animation of the hidden node situation encountered in wireless networking.
FIG. 2. SCREENSHOT FROM WIFIVL SUPPORT PAGES
WiFiVL supports access to ns2 to create a simulation of the same problem through two types of interface: a forms interface (Fig. 3) and a Rich Internet Application (drag and click), Fig. 4.
FIG. 4: AN RIA VERSION OF WIFIVL SCENARIO BUILDER
So, although the same parts of the architecture used in WiFiVL 1 and WiFiVL 2 are used in WiFiSL to generate a discrete event simulation in ns2, the scope of the simulation and the number of users are both limited by SL’s resource and communication restrictions. The adoption of OpenSim has resulted in a much more sophisticated learning environment: Wireless Island. Since there are no restrictions on number of islands available in an OpenSim installation, it was possible to dedicate a whole island to WiFi education. The island can host the WiFiVL and a large range of multimedia supporting materials. Furthermore, the design of Wireless Island was such that it can easily be shared using an OAR file. The island was designed around a centre circle with signposts that direct visitors to different themed areas. The signposts use the osTeleport command to transport avatars immediately to different parts of the island. Open exploration is also supported as avatars are free to fly around the island.
FIG. 3: A FORMS INTERFACE TO THE WIFIVL SCENARIO BUILDER
Initial attempts to move the WiFiVL into a virtual world featured Second Life - WiFiSL. This was interesting as an initial foray into virtual worlds for wireless networking education, but was far from satisfactory due to Second Life’s restricted communication facilities.
FIGURE 6: SCREENSHOT OF WIRELESS ISLAND
An example screenshot of the island is shown in Fig. 6. This shows the centre building with links that connect the different areas. A rich mixture of media is used on Wireless 978-1-61284-469-5/11/$26.00 ©2011 Crown October 12 - 15, 2011, Rapid City, SD 41st ASEE/IEEE Frontiers in Education Conference T2E-3
Session T2E Island, including video recorded lectures. To enable videos a suitable media server was required. A FreeBSD 8.0RELEASE was installed on a separate server. This hosts the Darwin Streaming Server which is an open source RTP/RTSP streaming server [19, 20]. The video lectures are taken from MIT Open Courseware [21]. Once the user clicks on the display the video is shown.
several of whom have gone on to carry out their major project and dissertation work using OpenSim for creating educational resources. It is appropriate however to reflect on the limitations of the suitability of Wireless Island as an open learning resource. As the same external ns2 server and OTCL translator has been used throughout the evolution of WiFiVL, it means that an interactive ns2 simulation facility cannot be incorporated into an OAR file. Neither can the streaming of video lectures. So, whilst many of the interactive exhibits and museum style features of Wireless Island are captured in the OAR file, two separate servers and software installs are also needed to create the full learning environment. These are freely available and open source, but are certainly not as convenient as having an “all-in-one” file. To a large extent this represents the historical evolution of WiFiVL. In the following case study, on Internet Routing, a different development path has occurred which makes a single file archive of all the facilities, including a simulator, possible. ROUTING ISLAND
FIGURE 7: NOTECARDS CAN BE “TELEPORTED” TO FOR CONTEXTUAL INFORMATION, AND PROVIDE FURTHER LINKS IF NEEDED
Another multimedia approach to the education of WiFi networks is the use of stock animations and display boards. These boards, as shown in Fig. 7 are used to animate and describe features of wireless networks. The students can walk through the introduction of Carrier Sensing Multiple Access, the Hidden and Exposed Node Problems and their ultimate solution in RTS/CTS with data exchange. Figure 8 shows a canned simulation being played back through an enhanced type of notice board known as a display board. Throughout the Island “learning paths” are represented by real paths, which a lecturer can configure, and which can be used to guide a student through concepts and experiments and contextual information, although unfettered exploration is always possible.
Internet Routing protocols are a keystone of computer networking education. They represent the practical application of theoretical algorithms learned elsewhere in the curriculum and force students to consider the core operation of the Internet. Two of the most commonly taught protocols are Open Shortest Path First (OSPF) which utilizes Dijkstra's shortest route algorithm, and the Distance Vector Routing Maintenance Protocol (DVRMP).
FIGURE 9: A SCREENSHOT FROM OSPF-LEARN
FIGURE 8: DISPLAY BOARDS PLAYBACK CANNED SIMULATIONS
Wireless Island has been evaluated positively with Computer Science undergraduates and Masters’ students,
OSPF-Learn [17] is typical of animated 2D web-based learning resources. It complements the static diagrams and textual explanations found in textbooks and allows the learner to single step through simple simulations, to test their understanding, and provides some contextual information and references for those wishing to study routing protocols further. Fig. 9 shows a screenshot from OSPF-Learn, part way through an introductory animation demonstrating how a routing table is built from a particular node. Users can select which node the animation is based
978-1-61284-469-5/11/$26.00 ©2011 Crown October 12 - 15, 2011, Rapid City, SD 41st ASEE/IEEE Frontiers in Education Conference T2E-4
Session T2E on - the one whose routing table is being built. In addition, animations can be stopped, started, and single-stepped. The algorithm is shown in textual pseudo-code on the left hand side. As each step is taken the pseudo-code is highlighted to show which part of the algorithm is being illustrated by the animation. Moving from this 2D set of animations to a virtual world version was also used as an occasion to introduce support for DVMRP, and to create a new routing protocol simulator, which was native to the OpenSim based virtual world. The ability to use C# in OpenSim, as opposed to Linden Scripting Language in Second Life, was essential in writing the underlying simulator. An OpenSim feature called miniregion-modules was also exploited. OpenSim also allowed for development to take part outside of the virtual world, with the authors being able to use their usual programming development environments, as opposed to the severely constrained basic text editor of Second Life.
FIGURE 11: A ROUTING UPDATE PACKET IS HIGHLIGHTED
FIGURE 12: A STUDENT VIEWS THE SAME NETWORK IN TWO DIFFERENT VISUALIZATIONS
FIGURE 10: CONTEXTUAL INFORMATION PROVIDED BY NOTICE BOARDS
In a similar way to Wireless Island, Routing Island has incorporated informational notice boards to provide contextual information, as is shown in Fig. 10. Different visual metaphors have been employed to better explain the differences in link metrics e.g. higher bandwidth connections are shown as having a larger girth, while delay is represented as the length of the connection. Color coding, and color and brightness changes are used to demonstrate a routing table being built, as routing table maintenance packets progress through the network, as shown in Fig.11. from end point to end point. The ability to create an OSPF or DVRMP network is another point of departure from OSPF-Learn, and more in keeping with Wireless Island. Groups of students can watch a routing scenario being created, utilizing either OSPF or DVMPRP, before attempting to create their own. The ability to walk around, and float above a routed network immediately attracted otherwise disinterested students, demonstrating again the ability of virtual worlds to engage students. Figure 12 shows a student invoking a different visualization metaphor for the same network shown in the lower plane.
From an open learning perspective Routing Island can be stored as a single self-contained OAR suitable for sharing via any file-based open learning repository. Interestingly, reasonably modern well equipped laptops running Windows 7 or Linux can run both an OpenSim server and one or more virtual worlds, allowing learners to work in an individual mode. CONCLUSION As Moore’s Law continues to deliver higher powered computation and graphics capabilities to affordable, individual computers, the capabilities of 3D virtual environments will provide higher quality user experience and become increasingly attractive as the basis for learning environments. In addition, many studies have shown that students are intrigued by, and engage with, immersive multi-user virtual worlds. The exploitation of 3D multi-user virtual worlds for education therefore continues to deserve research and development. We have suggested that the recent generation of virtual world technologies and the concept of open learning can usefully be brought together. While virtual worlds have demonstrated great potential for engaging students in exploratory learning, some of them are too restrictive in their business models and programmability to support open learning. OpenSim appears to have the best capability at
978-1-61284-469-5/11/$26.00 ©2011 Crown October 12 - 15, 2011, Rapid City, SD 41st ASEE/IEEE Frontiers in Education Conference T2E-5
Session T2E present for creating multi-user 3D learning environments that can be readily shared, via single, self-contained OAR files. In addition, it is possible to install an OpenSim server on a student’s laptop, in which case they can download an OAR file for individual learning, although this may require more technical expertise than is generally available. We have used two case studies of moving from 2D to 3D learning environments to demonstrate the capability of virtual worlds. In both cases students have engaged to a high degree and have improved their understanding of the topics almost as a side effect of participating in a shared learning environment. In conclusion, we believe that the use of 3D multi-user virtual worlds will become increasingly common in open learning. REFERENCES [1] [2]
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Kernigan, B. (1986) LEARN: http://www.cs.belllabs.com/cm/cs/who/bwk/. Perera, G.I.U.S., et al. Towards Successful 3D Virtual Learning - A Case Study on Teaching Human Computer Interaction. in the 4th International Conference for Internet Technology and Secured Transactions. 2009. London: IEEE Press. NASA, Learning Technologies Project FY10 Performance Report Project. http://www.nasa.gov/pdf/505587main_2010_ESE_LT .pdf. 2010. Linden_Labs. Second Life, www.secondlife.com. 2003 [cited 2009 January]. Kirriemuir, J. (2010) Virtual world activity in UK universities and colleges; Virtual teaching in uncertain times. Snapshot #8: Spring 2010. http://virtualworldwatch.net/wordpress/wpcontent/uploads/2010/05/Snapshot-8.pdf. Allison, C., et al. Educationally Enhanced Virtual Worlds. in 40th IEEE Frontiers in Education Conference, 2010. FIE '10. 2010. Washington: IEEE. NASA. Earth-Moon Activity. Education Weekly Activity Report (WAR).. 2010 [cited 2011 March]; Available from: http://education.jsc.nasa.gov/war/archive/war_roll_u p.cfm?&date=20100401.
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Kurose, J.F. and K.W. Ross, Computer Networking. 2001: Addison Wesley. Peterson, L. and B. Davie, Computer Networks: A Systems Approach. 2003: Morgan Kaufmann. 813. Tanenbaum, A.S., Computer Networks. 4th ed. 2002: Prentice Hall PTR. 950. Kurose, J.F. and K.W. Ross, Computer Networking: A Top-Down Approach. 4th ed. 2007: AddisonWesley. 880. Getchell, K., A. Miller, and C. Allison. A TCP Learning Environment. in 6th Annual Conference of the Subject Centre for Information and Computer Sciences. 2005. York: Higher Education Academy. Allison, C., et al., Global Connections for Lasting Impressions: Experiential Learning about TCP, in Advances in Web Based Learning - ICWL 2009. 2009, Springer Berlin / Heidelberg. p. 48-57. Sturgeon, T., C. Allison, and A. Miller. A WiFi Virtual Laboratory. in 7th Annual Conference of the Higher Education Academy Subject Centre for Information and Computer Sciences. 2006. Dublin, Ireland: HE Academy. Sturgeon, T., et al. WiFi Virtual Laboratory. 2006 [cited 2007 January]; Available from: wifi.cs.standrews.ac.uk. ns2. The Network Simulator, version 2. 1995 [cited 2009 January]; Available from: http://www.isi.edu/nsnam/ns/index.html. Allison, C. and B. Ling. OSPF-Learn: http://ospf.cs.st-andrews.ac.uk/. 2006 [cited 2011 March]; http://ospf.cs.st-andrews.ac.uk/]. Available from: http://ospf.cs.st-andrews.ac.uk/. Weatherall, D. OTcl (MIT Object Tcl). [Programming Language] 1995 [cited 2009 January 2009]; Available from: http://otcltclcl.sourceforge.net/otcl/. DSS (2011) Darwin Streaming Server: http://dss.macosforge.org/. IETF, Real Time Streaming Protocol (RTSP). 1998. Gallager, R., Gallager, Robert, 6.450 Principles of Digital Communications I, Fall 2006. (Massachusetts Institute of Technology: MIT OpenCourseWare). 2006.
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