Exploiting Virtual Reality Techniques in Education and Training: Technological Issues
2.4 Virtual Environments: Educational Context
When one considers virtual environments or virtual reality based systems there is a tendency to think of someone wearing a head mounted display and who is immersed in a computer generated environment. This view happens to be just one instance of a range of VR systems and focusses on the method of delivery to the user. However, it is better to take the term ĎVRí in a broader context. In doing so there are more realistic and exciting possibilities for application in an educational situation. The key to the definition of a VR system lies with a description of what the system enables one to do rather than basing the definition on a technology based description.
In the broader context, a VR system allows a participant to:
- Become immersed in a completely synthetic computer generated environment.
- Achieve a sense of presence in the environment.
- Become un-inhibited where conventional laws of physics can be controlled in a way that assists greater understanding.
- Achieve a sense of non-real time; where situations can be presented in slow or fast time.
- Achieve a high degree of interaction that can equal or exceed that achievable in the real world.
- Interact in a completely natural and intuitive manner with the synthetic environment.
- Repeat the task until the desired level of proficiency or skill has been achieved.
- Perform in a safe environment
One could claim that these are also attributes of a simulator system such as a flight simulator. Indeed, a flight simulator is a form of virtual environment, but one where the external world is represented by a computer generated visual and the user (trainee pilot) interface is based on a real cockpit. It is even feasible to provide trainee pilots with a completely virtual system, including virtual representation of the controls. However, analysis of the key training requirements clearly shows the importance on interaction with real controls. As long as an appropriate visual or audio response is perceived as a result of a pilot action then the representation of the aircraft electronics (avionics) can be real or simulated. To be an effective training environment the simulator must react and behave in an identical manner to the real system. It is the 'look, touch and feel' of the simulator that is important if the training is to be transferred to the real world. Today, flight simulation has become so important that most airports provide their own simulator facilities for aircrew to maintain their knowledge of system behaviour. Given the inherent reliability of the aircraft system, and the infrequency of faults occurring it is crucial for aircrew to train under simulated emergency fault situations. The flight simulator is the only practical way of doing this and illustrates how useful and cost effective virtual or simulated environments can be. Unfortunately, the cost of the enabling technology to provide adequate simulation capabilities has been previously very high and only affordable by the aerospace industry. However, rapid advances in technology development has brought the cost of these systems down to a mere fraction of their original price. Moreover, the necessary software development tools have undergone a revolution making it significantly easier to create and maintain a virtual environment.
2.5 Generic Model of an Educational VR Environment
The exact form of a virtual environment will be considered later but for now it is best to adopt a more generic description, refer to Figure 1.
Figure 1 Generic Model of an Educational Virtual Environment
This simple representation of a virtual environment system identifies the closed loop nature of a VR system involving a user, input/output peripherals and a simulation environment. In order to provide an educational perspective it is important to control the simulation by a training/education programme.
Training Programme: The training programme represents a training module that takes advantage of the overall VR system. It is essentially an application programme that is executed on the host computer and its purpose is to take the student through a carefully designed syllabus. This might take the form of conventional question/answer sessions or more likely, it will initiate responses according to the performance of the student. It will be important to ensure that the VR system is used for an appropriate task. For now it is best to think of applications where 3D environments are important, for example engineering design.
An important aspect of the training programme will be the use of appropriate performance measures. In many ways the training programme will behave like a computer based training system, the programme moves forward in response to correct answers being supplied by the student.
Model or Simulation: The model or simulation is a mathematical representation of the system being used. It needs to take account of dynamic behaviour in response to the studentís input. For example, a mathematical model can be produced that represents the dynamic behaviour of a petrol engine under different load conditions. Students could have the ability to disable one or more spark plugs and examine the drop in engine performance. Very sophisticated mathematical models can be written but it is the way that these are associated with an auditory and visual representation of the system that is important. In the example given it is possible to produce an auditory and visual representation of an engine misfiring on three cylinders instead of running on four. Students find it much easier to understand things from diagrams or models than simply looking at graphs or numerical output. The simulation can also make it possible to explore what if situations that would otherwise be impossible or dangerous to perform. This further improves the studentís level of understanding. It would even be possible to let the student explore a system and make mistakes. In this way the student will get the best possible understanding of the system operation.
It is the peripheral technologies that most people closely associate with VR since these represent the userís interface with the VR system. The peripheral technologies simply represent the input and output devices and of course include head mounted displays and glove like devices etc.. However, the particular technology used is of critical importance and can mean the difference between a usable or useless system. Furthermore, the cost of the whole system is influenced greatly by the peripheral technologies. Since the user interacts with the VR system by means of the peripheral technologies it is extremely important to ensure that these are matched to the perceptual needs of the user. An inappropriate interface may actually inhibit the learning process.
- Input: Input refers to the interaction devices that are used to interact with the virtual environment. Conventional input devices such as keyboards and mice can be used but since we are ultimately dealing with a 3D environment a different style of interaction device must be used. These mainly include joysticks and glove devices, though there are other suitable devices.
- Output: Output refers to the technology that provides stimuli to the user and is not just restricted to visual representations. It is more appropriate to think in terms of all the userís senses (olefactory or smell output devices are perhaps the exception). The range and configuration of output devices is enormous and ranges from conventional display monitors, head mounted displays through to 3D sound systems. The output device will influence the overall VR system architecture and hence determine the cost of the whole system. Therefore, it is extremely important to employ the correct level of output technology for a given application. It may even be necessary to combine a number of output devices to compensate for limitations in the technology.
User / Student: The user/student is a very important part of the VR system. Figure 1 has been drawn in a way that emphasises the feedback role that the user provides in a VR system.
The important aspect of the generic model is that the virtual environment must be controlled by the education/training programme. The relationship between the education/training programme and the simulation is the heart of the educational system. At this stage it assumed that appropriate input/output technologies will be used.
For very simple systems this description is quite adequate but more complex situations exist where the student has to be advised by the tutor on a continual basis. In this instance the training programme must be designed to accommodate independent tutor control. The type of input/output must also be carefully considered.
Virtual Environments Visualisation