TIPOS DE ACTIVIDADES DE PROMOCIÓN DE DERECHOS POR AÑO

In moving towards the concrete instantiation of the system, five key design decisions were made with respect to the technologies adopted in the system. Whilst made independently, each decision considered issues of integration and cooperation between system components. For each decision, the functionality offered is presented, along with comments outlining the rationale adopted and/or alternatives considered. Table 9 presents these decisions and is followed by a discussion of the issues surrounding the choice of 3D technology adopted and the impact that this has on the operation of the system itself.

Comparison of 3D APIs, First Person Shooter Games and MUVEs

As a number of 3D technologies exist, it is important that the differences between each are understood. Several 3D technologies were examined in the course of this work. From an archaeological excavation perspective, for students to explore and understand an excavation site it is important that they are able to access realistic materials in an environment that encourages self-motivated discovery. When developing the excavation simulator, three different types of 3D environment were considered: first person shooter games, MUVEs and 3D APIs. Each category of 3D technology was evaluated against four of the criteria as discussed in section 4.4.1:

• Learner Engagement.

Design Decision Functionality Offered Comments

Use of Second Life

for 3D visualisations. Second Life provides a stable, accessible environment which supports extensive modification and scripting. The changeable perspective enables users to adopt a first person perspective when required to focus on specific objects, with a wider field of vision being possible when navigating the excavation site. The comprehensive scripting engine offered by Second Life provides support for modification of the environment as well as communication with external services, hence enabling the link between the 3D synchronous interface provided by Second Life and the excavation logic behind the LAVA simulations. The shared environment space provides support for collaboration amongst student groups, with access control mechanisms making it possible for individual student groups to be separated into different, private regions.

Alternatives to Second Life include Active Worlds and Open Simulator, with Open Simulator being compatible with the Second Life client.

Unlike Second Life both Active Worlds and Open Simulator have only limited scripting capabilities, thus making interaction with external services more difficult. Whilst Open Simulator will eventually provide a Second Life compatible scripting engine which can be extended with alternative scripting modules, the current scripting support is only partially implemented

The use of MUVEs over first person shooter games.

Both first person shooter games and MUVEs support the desired 3D perspectives of an environment. However, unlike game based choices, MUVEs do not have a pre-defined concept of levels, progression or game play. This makes it possible for the MUVE environment to be fully customised to the requirements of LAVA. Built on a larger scale, MUVEs also provide support for the development of large environments for students to explore. Whilst this support is provided in many game engines, access to the engines is often strictly controlled through licensing agreements. MUVEs do not suffer from this administrative burden as client access is generally freely available.

In terms of developing in first person shooter games, investigative work was carried out using Quake 2 and Unreal Tournament as well as the Unreal Runtime engine. The control offered by first person shooter games in terms of creating environments was good; however, the underlying concepts of levels, progression and killing did not fit well with the concepts of levels and progression within the excavation scenario. In addition it was found that support for modification of the underlying environment was not comprehensive, making it difficult for excavation processes to be accurately modelled. Use of MMS. Group based access to excavation data was an important factor in deciding to use

MMS to build the 2D user interface. As a learning environment MMS provides support for authentication, authorisation and grouping of users. In addition it also supports the management of course modules, sequencing of resources and progressive revealing of learning materials. Not only are these aspects of MMS directly relevant to the requirements of LAVA excavation simulations, but they also assist in the management and maintenance of LAVA excavation simulations.

Alternative learning environments were explored; however, the lack of extensibility was an issue. MMS provides a clearly defined interface which facilitates the swift development of third party resources without requiring changes to the underlying structure of existing ones.

Use of Apple QuickTime Photo Based Panoramas.

The interactivity provided by Apple QuickTime Photo Based Panoramas is desirable. The ability for students to zoom in on regions and adjust camera angles also adds value by making it possible for students to obtain an understanding of a remote region from a variety of alternative perspectives.

The Apple QuickTime format was adopted owing to the availability of panoramas of the excavation site in this format. Whilst the format has been used in the excavation simulation of the Sparta basilica, alternative formats are equally well supported by the resources developed in this work.

• Realism.

• Accessibility.

When considering each of the three classes of 3D environment, it quickly became apparent that all provide support for each of the criterion, with MUVEs and first person shooter games providing far more developmental support in terms of pre-defined environments. Given the out of the box applicability of MUVEs and first person shooter games, the development of a customised 3D environment based on a 3D API was abandoned.

Unlike first person shooter games, MUVEs do not have any predefined objectives or goals. However, given the customisation supported by many first person shooter games, this does not automatically preclude their use. Indeed, first person shooter games have been used in a variety of applications, with the research and training communities quick to adopt them as the basis for specialised simulation platforms.

The virtualisation of the Urban Search and Rescue arena of the National Institute of Standards and Technology (NIST) Reference Test Facility for Autonomous Mobile Robots (Unreal Engine 2.0) [208] is a significant use of the first person shooter genre of computer games for serious use, as is the visualisation of the University of Cambridge’s William Gates Building (Quake Engine) [209] and the development of a virtual architecture course using game engine technology at the University of Auckland, New Zealand (StringCVE based on the Torque Game engine [210]) [211, 212].

In addition, several tools have been developed which make it possible for external data to be fed through network sockets in to game engines [213], which are then able to represent the data using game robots (bots) which are simulated players running simple reactive programs, thus mirroring the ability for external stimulus to direct activity with MUVE environments. Given the success of the use of game engines in non-gaming fields and the development of tools to feed data from the real world into virtual reality simulations, it seems as though the functionality provided by game engines rightly justifies their use in more realistic simulation environments. However, one significant drawback featured in first person shooter games relates to their focus on user interactions. Within first person shooter games the environment in which the action occurs is predominantly part of the background material, with the main focus on user to user (or sometimes more accurately user to enemy!) interactions.

In contrast, MUVEs provide rich support for users to interact equally with other users, the environment and any objects within it. Unlike first person shooter games, the environment within MUVEs is entirely user generated and customisable. Thus it can be developed to support exactly the type of interactions required. This ability adds significant weight to using MUVEs within LAVA owing to the emphasis on environmental modelling and interaction that occurs within an excavation project.

In terms of accessing MUVEs and first person shooter games, both technologies make use of a variety of network protocols often generating both TCP [214, 215] and UDP [216] network traffic. First person shooter games are generally designed to require limited network traffic in order to ensure fast response times over a variety of network types and are generally reasonably resilient to changes in network traffic patterns [217]. MUVEs however are less efficient, partly due to the large numbers of communication mechanisms offered (voice, text, video, etc.), with many opening a large number of network connections [218-221]. This means that MUVEs have the propensity to consume significant amounts of bandwidth if not carefully managed. Indeed, many MUVEs have minimum bandwidth requirements which precludes their use over analogue and ISDN dial up connections [222]. When considering a university network or home broadband connection, the bandwidth requirements of both first person shooter games and MUVEs can normally be met without difficulty, with university networks in the UK generally being adequately provisioned to support simultaneous access by hundreds of users. However, given the remote hosting model adopted by most MUVEs, having an entire university online simultaneously would likely be problematic, hence the increasing interest in open source MUVE technologies which allow locally hosted MUVE environments within universities and commercial organisations.

Irrespective of the networking resources required by MUVEs, their applicability to LAVA excavation scenarios is compelling. Whilst solutions using both first person shooter games (using the Quake 2 game engine) and MUVEs (using the Second Life grid) have been explored, only the MUVE based approach has been adopted given the significant benefits it offers in terms of environmental modification and user interaction.