System Structure and Design

Table 7 presents five design decisions which relate the functionality required by the system and how it is achieved. Initially focussing on first principles, which are developed by later decisions, the table identifies the building block decisions that are made before outlining their impact on the direction of this work: for example, the decoupling the user interface and excavation logic makes segmentation of the game play into synchronous and asynchronous, 2D and 3D modes of interaction possible. Table 8 expands on this by considering how different modes of interaction can be used to provide educational benefits within a LAVA simulation. In both tables, for each decision the motivation is presented along with a commentary assessing its impact on the system. This is followed by a discussion of the issues surrounding the modelling of the excavation in 2D and 3D interfaces at different phases of the process.

Separation of Type of Interaction and the Levels of Abstraction Presented

As an important aspect of this work, the separation of synchronous and asynchronous and 2D and 3D interactions is an important design decision that has a direct impact on the interactions offered to students. Primarily tied to the level of abstraction adopted for each learning exchange, the separation is undertaken in order to allow students to develop skills in the virtual environment which can be applied to a real world excavation, for example:

Design Decision Motivation Comments

Development of a service

based architecture. Adopting a service based architecture adds flexibility and makes it possible for components of the system to be used in a variety of applications. This enhances the generality of the solution and allows updates to be applied easily. In addition this approach allows configuration and control to be exercised from the server side, thereby easing deployment to a large number of clients.

An alternative approach would be to develop a standalone application. This would make deployment of the software and updates more difficult to manage. It would also reduce the accessibility of the system. However it would make it possible for the software to be used without Internet connectivity, something a Web-based approach does not allow for.

Decoupling of user interface

from excavation logic. Maintaining separation between the logic that controls the excavation simulation and the interface through which it is controlled makes it possible for alternative interfaces to be developed without requiring changes to the underlying excavation logic.

This is facilitated by the adoption of a service based architecture. The ability to provide several interfaces to the excavation process aids accessibility and encourages use in different environments: for example, on a PDA, mobile phone or set top box.

Use of users, groups and resources abstraction to facilitate organisation and mediate access to system functionality.

Organising access to resources and maintaining separation of groups is important in providing an infrastructure which supports collaborative groupwork. It allows resources to be allocated to groups. The members of which may share allocated resources and, where appropriate, may have a common view of data associated with each resource.

The system provides a clear organisational structure which supports the use of access controls and provision of user rights.

Resources designed as independent MMS components built to conform

to a common interface which enables functionality and data to be bound together.

Developing the components of the system in this way allows for underlying learning environment functionality to be utilised: for example, sequencing, user authorisation and protection mechanisms. In addition the flexibility offered by this approach makes it possible for resources to be used in alternative applications.

An alternative approach would be to develop a single monolithic resource which fulfils the requirements of this work. This resource would have limited application in alternative domains and would be difficult to maintain.

Use of a relational database to model state related to the excavation.

By eliminating repetition of data, this approach provides a flexible and efficient way to retrieve and update excavation state data. Classifying tables into a hierarchical structure, with first class tables of student, group and excavation and other tables relating directly to one of the above adds flexibility and aids maintenance. A well defined API to the data is used which reduces the complexity required in other parts of the system and allows changes to the data structure to be made without threatening the integrity of the system.

As multiple types of data are being used, with the relationships between them significant to the dynamics of the system, it becomes important to have a well developed approach to describing, storing and retrieving data.

Design Decision Motivation Comments

Separation of synchronous and asynchronous game play into separate phases of the excavation.

Separation of 2D and 3D game play into separate phases of the excavation.

The use of synchronous and asynchronous interactions in a 2D or 3D environment is tied to the level of abstraction adopted. Throughout the excavation simulation, different levels of abstraction are used to present different aspects of the excavation to students, with the choice aiming to maximise the educational benefit of each interaction.

For example, in the 2D environment LAVA abstracts away from the physical activities associated with digging trenches and dusting for finds, as the skills required to manipulate the keyboard and mouse to achieve these activities in a virtual environment are very different to the skills required to achieve these activities in the real world. This allows LAVA to draw student focus to aspects of the excavation process that are applicable in both the simulated 2D and real world environments: report writing, strategy, identification of requirements, application of resources etc.

Similarly, in the 3D environment LAVA focuses on activities which maximise the use of skills applicable to the real world: for example, identifying objects visually, considering architectural features etc.

Separating synchronous and asynchronous interactions also leads to a cleaner design. If the 3D synchronous and 2D asynchronous views were simultaneously active, problems in maintaining the consistency of state would arise. Separating the domains where the different modes of interaction are active allows the consistency of system state to be easily maintained without the need to freeze state in either environment. This would effectively render the 2D asynchronous environment inoperable for possibly long periods of time.

• The skills required to identify and apply resources to the excavation of an area of the archaeological site are likely to be similar in both types of environment. However, as access to a virtual excavation is mediated through the use of a computer, the type of skills required to actually carry out the excavation work are likely to be very different; the process of digging a trench with a mouse in the virtual environment is significantly different to the process of digging a trench with a shovel in the real world. In this way LAVA uses a 2D asynchronous interface to allow students to focus on the processes associated with the planning of excavation work in order to enable the development of skills that are applicable to real world excavation projects.

• When considering the process of reviewing architectural elements and presenting findings, the skills required are similar in both virtual and real world environments, with the concepts of space and context being important factors to consider. Thus LAVA makes use of a synchronous 3D interface to allow students to understand the context and spatial relationships between architectural elements whilst engaging with each other and the environment, just as they would in a real world scenario.

The approach adopted draws from a number of well established gaming methods. To illustrate this point, consider an example which is drawn from popular football games. The 2D asynchronous interface presented to students via MMS shares many characteristics with the popular and highly successful Championship Manager [206] football management game – focusing primarily on the development of skills which can be practiced in a virtual environment and applied in a real one without significant changes. Whilst other titles focus on providing a synchronous 3D interface which delivers a match like environment that encourages users to learn how to control each player [207], Championship Manager provides a more abstract asynchronous 2D interface, as shown in Figure 61, which focuses on the skills and strategies required to build a successful football squad. In this way, the learning outcomes of using Championship Manager could be applied to real world football management, in much the same way as the learning outcomes associated with the LAVA 2D interface could be applied to real world excavation scenarios. In contrast, FIFA 2008 [207] provides limited transferrable skills with respect to playing a match: with users learning game specific interactions which have limited applicability in real world matches; being able to manipulate a joystick to score a goal in FIFA 2008 clearly has no direct application on being able to score a goal in a real football match. Thus the opportunities for the application of the skills taught by FIFA 2008 are limited to a specific, narrow domain.

However, the 3D synchronous interface offered by FIFA 2008, as shown in Figure 62, does provide tangible benefits with respect to developing cooperation strategies between multiple players within a single match. In addition, the realistic environment presented also increases a users’ familiarity with the procedures undertaken during a football match: for example, substitutions, timing and scorekeeping. It is for these reasons that the later phases of the virtual excavation make use of a

synchronous 3D environment; when student teams are ready to analyse reconstructions of the excavation site and present their findings, the cooperation encouraged in the 3D synchronous environment is directly applicable to real world scenarios, and as such is educationally beneficial. Additionally, the ability for students to assume a familiar first person perspective when reviewing architectural elements or presenting their excavation findings is also clearly applicable to real world scenarios and is thus made possible in the synchronous 3D environment.

Modelling Interactions

In addition to the educational motivation driving the separation of the modes of interaction offered in the simulations, an added benefit of maintaining separation exists from the point of view of system design. Within the 3D viewport time is modelled in an inelastic fashion; it is not possible for individual group members to jump forward in time as this would cause problems with other group members who were not intending to progress time forward so quickly. In order to maintain consistency between group members, time is modelled in a uniform synchronous fashion throughout the 3D environment. This poses a problem when it comes to undertaking slow and repetitive work using the

Figure 61 – 2D Management Interface used by Championship Manager 2007

2D asynchronous interface. If both the 3D synchronous and 2D asynchronous views were simultaneously active, consistency issues would quickly arise, with users of the 2D asynchronous interface making changes to the environment currently being explored by users of the 3D synchronous interface. How these changes would be propagated into the 3D environment remains unclear as any activities in the 3D environment have been undertaken assuming a fixed starting state to the environment. Interleaving changes made in the 3D synchronous and 2D asynchronous environments may be feasible, however given the lack of coordination between the two the result would likely be difficult to accurately predict.

One solution to this problem would be to block access to the 2D environment when users were active in the 3D environment and vice versa. This approach would, however, have a negative impact on the anytime-anywhere accessibility of the simulations, creating a direct link between the previously independent interfaces which breaks the service orientated approach adopted by this work. Instead, a logical separation of the interfaces has been adopted, with each interface tasked with delivering certain phases of the excavation to students. Not only does this ensure consistency of state and reliability of presentation, but it also ensures that each interface remains independently maintained thereby reducing the complexity of the system whilst maintaining the desired service orientated architecture.