To overcome these problems, the Interact project has developed a toolkit where by simulations can be encapsulated within a hypermedia shell, allowing this environment to provide the supplementary information normally supplied by a lecturer. In order to achieve this goal we have developed two primary software tools:
allows messages to be passed from Mosaic to another application . The ICF also provides the ability to use HTML fill out forms to pass data from Mosaic to a running application.
this is a object-oriented simulation toolkit which takes advantage of the facilities provided by W3 technology and the ICF. The PM provides a layered architecture which allows the same core computational model across a number of engineering domains. These two tools combine to produce a powerful and flexible environment for the development and delivery of educational simulations.
Many systems in engineering can actually be modelled using the same underlying set of equations and it this separation between the abstract computational component and the interface which grounds this model in a particular domain which lies at the heart of the ISE. The hypermedia environment providing an additional level of customisation.
Although a particular simulation may be used in several different courses, the role played by the simulation may be different in each case. By using Mosaic and the W3 , courseware can be easily distributed, with new courseware being integrated without having to reconfigure the underlying simulation.
The figure below shows the architecture of a complete system built using the ISE.
Figure 1 The Interact Simulation Environment
The diagram shows how a layered approach is used: the simulation model and user interface are normally in the same program, with the ICF in the background passing messages between the simulation and Mosaic.
The communication between Mosaic and the simulation is bi-directional, the simulation can send messages to Mosaic to view a particular document. The ICF allows messages to be stored as separate script files or directly embedded within an HTML document.
These messages can be used to implement a high-level interface to a simulation. Users need not read instructions from a document and then perform the actions described, this can be done from inside Mosaic, leaving students free to concentrate on their studies rather than struggling with the simulation's user interface.
One of the largest obstacles facing the production of reusable educational simulations is that members of the academic community seem to be particularly prone to the not invented here syndrome - since ISE simulations exist independently of their courseware it is easy to add additional elements to suit a particular course. One of the advantages of using Mosaic and the W3 is that, when adding new courseware, is that it is extremely easy to link it in with existing resources, regardless of where the resource is.
The Interact Simulation Environment allows simulations to be used in a number of different ways:-
The simulation can be used with lectures to show some particular effect or phenomena, by embedding commands into a HTML document allows a very simple interface for which the demo can be controlled.
The simulations can be used by students on their own, this is where the hypermedia shell comes in to its own, as it can provide help and guidance to the student. The distributed nature of the web also allows students to share resources for the simulation provided by the Presentation Manager.
Where a simulation is used as a short lab experiment, the use of Mosaic can prove invaluable. Normally labs are run on fairly tight time schedules and regardless of good the interface to a computer program, if a student has never used it before they can spend more time working out how to use the interface rather than the getting through the experiment. By putting the lab sheet in an HTML document and embedding commands to the simulation, the setting up of the simulation can be done from the Mosaic, thereby allowing an easy and consistent interface to the complexities of setting up a simulation.
The PM uses the ICF's own scripting language to achieve object persistence for all of its objects, this allows objects to be distributed across the Web, in the same way as any other resource. This provides universities with an easy way of sharing resources associated with a particular simulation.
The diagram below shows how a script containing ICL commands can be used by simulations running at a remote site.
Figure 2 - Controlling a simulation from W3 courseware
When a user follows a link to a .ish file it is transferred to the local machine and executed using the appropriate 'viewing' program. This results in a message being sent via the ICF to the appropriate program, where the built-in ICL interpreter converts the message to data and commands appropriate to the recipient. The PM provides a set of features that can be used across the Web.
The PM has its own graphical toolkit that allows graphical objects such as meters and strip indicators to be saved in the ICL, once saved these graphical objects can be reloaded into a simulation at run time to re-construct the saved interface, this can be done from local files or across the Web. For example a simulation may be used at several sites but the graphical view of the model may be tailored to suit the course in which the simulation is being used. This feature has also been used to allow the collaborative prototyping of interfaces, with developers working simultaneously at different sites.
A snapshot is simply a record of the values of all of the variables in a simulation. This information can be saved in terms of ICL and therefore can be shared on the Web. The PM also provides a 'deluxe' snapshot facility which creates an HTML document on the fly which gives a list of the variables with their descriptions and the current value of each variable, it also provides a link to a file of commands which will recreate the described state.
See Figure 3 below.
The PM can also record events that happen within a simulation, in particular changes to input variables which will have an effect on the output of the simulation. These events are recorded in terms of ICL and can be replayed back at anytime. The PM also provides a 'deluxe' version of the replay files which gives an HTML account of what happens in the simulation in chronological order and of course a link to a file of commands to recreate the events in the simulation.
The PM uses Mosaic to deliver all its help. The documents used to provide help can, of course, use the ICF to directly control the simulation. By using embedded ICF commands and fill out forms to set up the simulation, it is extremely easy to create features similar to Microsoft Wizards, whereby the users are guided through questions which result in the simulation being setup in the desired manner.
Figure 3 - Example of a HTML document created by the PM
Link to actual document .
describing common or 'interesting' initial conditions or system states.
for the simulation's user-interface. This can be used to emphasis or hide various elements of the system being simulated, or to display a viewpoint appropriate to a particular domain.
The core of our prototype system is implemented as a pair of CGI scripts. One script writes a customised fill-out form, which is specific to the domain of the query, into which the user types her query which is then passed on to the second script for processing. This latter script extracts the query and emails it to the appropriate domain expert and returns a short report to the user giving details on how her query is being dealt with.
Answers in the AnswerWeb are, of course, free to exploit any of the features of the ISE. Experts can therefore include a textual description of the answer, but where appropriate, use snapshots or replays to use the simulation as a vehicle for answering the question. Also by using the W3 the questions and answers can be transparently distributed across a number of sites.
i Thomas R., The Interact Home Page (1993)
ii Thomas R, Neilson I, Slater A, Smeaton C. "The Interact Project - An Integrated Engineering Simulation Environment". Proceedings of the Conference on CAL in Engineering 1994.
iii Slater, A., The Interact Communication Facility. Proceedings of the first International WWW Conference, Geneva 1994.
iv Smeaton C. , Thomas R. , "The Presentation Manager". INTERACT project internal report 1993.
v Smeaton C., The Interact Simulation Environment Home Page 1994
vi NCSA Mosaic Project, WWW Home page
viii Berners-Lee T. HyperText Markup Language (HTML)
ix Ackerman, M. S. and T. W. Malone. "Answer Garden: A Tool for Growing Organisational Memory". Proceedings of ACM Conference on Office Information Systems, 1990, 31-39.
x NCSA Mosaic Project , Mosaic for X version 2.0 Fill-Out Forms Support 1994
He is currently working towards an MPhil on A Environment for Simulations in Education.
Email :- calum@cee.hw.ac.uk
WWW Home page :- http://www.eng.cam.ac.uk/~calum/
Alan Slater is a Research Associate in the Department of Computing and Electrical Engineering at Edinburgh's Heriot-Watt University. He is currently employed on the SERC/DTI MOBIT project which is developing industrial Intelligent Training Systems in collaboration with a number of industrial partners. Alan has also worked on a number of large European projects, funded under the CEC's ESPRIT programme, investigating model-based diagnosis and ITSs. During work on the INTERACT TLTP project, which aimed to produce an environment for delivering educational simulations, he became interested in hypermedia tools and the W3. He is currently in the final stages of preparing a PhD thesis which is based on his work in the field of ITS systems. This thesis identifies a generic architecture for intelligent agents which is used to provide the basis for realising the two main modules of an ITS system: the domain expert and the tutor. As part of the MOBIT project he is examining the possibility of delivering computer-based training material via W3 tools, the training domains for MOBIT being control of a nuclear power plant (with Scottish Nuclear) and the manufacture of computer systems (with Digital Equipment Scotland Limited).
afs@cee.hw.ac.uk
http://www.cee.hw.ac.uk/~afs/
