Rendering OpenSim Function Interrelations for User Guidance

support are described in this section. This tool facilitates users understanding the conflicting or cohesive nature of similar functionalities from different MULE management areas.

5.3.1 A Framework of OpenSim Functions for Management

OpenSim based MULE management policies depend on relevant OpenSim functions for their implementation. Academics have to rely on these functional behaviours and their interrelationships to decide appropriate policy implementation mechanisms. Therefore, effectively the OpenSim function categories must be used as a framework for this tool design. The following function category framework was prepared (Fig. 5.2) based on the system study findings to facilitate policy implementations in OpenSim.

As shown in the framework, OpenSim based MULE management policies have to be implemented in coordination with the existing (generic) learning management policy implementations. Higher level management policies often get precedence in defining the ways learning activities are conducted and managed. For example, an institution specific server access policy may not allow certain network communication ports and protocols from outside, which can affect the access of OpenSim environment from public networks. Therefore, due considerations should be given on generic learning management policies when trying to implement MULE management policies.

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Figure 5.2: OpenSim function framework for policy implementation

The function categories, indicated as OpenSim functions in Fig 5.2, determine management practices within OpenSim. Among these categories avatar activities are the fundamental mechanisms that students interact with in a learning environment in OpenSim. This can be the most challenging set of functions to manage as the users interact with the environment through these; hence they are highly vulnerable to misuse by SR-Low users, yet the restrictions on these functions can be costly in terms of perceived usability. The policy implementation mechanisms in this category have a higher level of association with SR aspects than the EM aspects guiding the students on their expected behaviour within the learning environment.

OpenSim System Management core functions include land, content, user and group management. As discussed in Chapter 3, these function groups follow system models that define their behaviour and functional interrelationships. Importantly, most of the OpenSim system management activities are done through a land specific function category; hence the implementation mechanisms tend to incorporate more EM aspects; SR aspects too can be essential for certain user engagements, however. For policies that need to be implemented using content related functions both aspects of SR and EM can be important depending on the learning arrangement according to the taxonomy. User management related functions can be used to promote SR aspects in policy implementation; e.g. appropriate avatar naming strategy can help shape student behaviour. With the group related functions EM based management practices are important in managing group roles and abilities, while SR aspects are essential when defining member behaviours.

The advantage of this framework is that academics can be given a high level, concise view on available function categories in OpenSim. To provide more concrete user support for using OpenSim functions a tool was developed, which is discussed in the next section.

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5.3.2 A Network of OpenSim Functions

Over 200 unique OpenSim functions with about 350 relationships among those functions that can be relevant to the learning with OpenSim were identified. Considering this complex information is a challenging task for any user. To overcome this challenge and analyse the inter-function relationships, an approach with graph analysis was followed.

Graphs, for representing complex interrelationships, have been widely used in multiple disciplines with various applications. Graphs can facilitate a rapid uptake of abstract information through visuals [209]. A directed MUVE function graph (di-graph) G can be defined as G = (V, E); where V is the set of OpenSim functions (vertices), and E is the set of relationships, also known as edges, between those functions. Furthermore, the nature of these functions and their structural design seems to form a complex network. With the large number of functions and their complex interactions, more intuitive user support tools are required for OpenSim based MULE management.

In research on an interactive visualisation tool design for e-learning management, Jyothi [210] emphasised that the visualisation of network interactions in a graphical way assists the moderator or the instructor to understand, at a glance, several important concepts without any further investigation or research. Visualisation tools embedded in e-Learning systems allow teachers to reveal useful characteristics appropriate to the management of learning activities [211]. However, the mere visualisation support in a graphical way cannot effectively support educators; a successful guidance tool should provide interactive operations to manipulate the graphics such as zooming and filtering [212]. Therefore, the guidance tool for helping users on OpenSim functions has to be dynamic and intuitive with an intrinsic flexibility given to the users to select the required sub topologies from the entire network. This effect of popping out the selected graph from the rest can help the users to focus on their selected policy and implement those rapidly. Using the 'pop-out' paradigm allows probing of elevated information from graphs, making it a viable approach for efficient data visualisation [213]. The network analysis and visualisation tool Gephi [version 0.8α] [214] was used, as it aids users to rapidly visualise function interdependencies and statistical analysis of the network.

Gephi supports multiple formats of node and edge data inputs to generate the graph view of a complex network. As a result, Gephi has been widely used in complex network analyses such as social networks, biological networks etc. However, most of these complex network data are either readily available for generating the graphs or can be easily extracted from the sources in a format that is supported by visualisation tools such as Gephi. With respect to OpenSim functions neither of these options was possible; therefore, this function topology was developed by creating the data source of functions and interactions identified through system studies.

Gephi allowed two options to develop the network; either to draw the topology on the visualisation template itself using the draw palate or write the graph topology source using the syntax it understands. A graph description language such as DOT [215] can be used to define the textual syntax structure of the graph topology, which is supported by Gephi syntax processor. The DOT language has a simple structure and syntax that enables the expression of nodes links and formatting information for presentation. A DOT language script with basic properties to represent a selected sub network topology of OpenSim function network is shown in Fig. 5.3.

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Figure 5.3: An example graph topology written in DOT

Once the *.dot script file is loaded to Gephi, it generates the network with nodes and edges. Further customisations can be easily done to the selected nodes and edges for enhanced presentation effects using the Gephi GUI tools. In particular, editing the graph using the GUI seems more efficient when only few changes are needed. The corresponding sub topology for the DOT script shown in Fig. 5.3 obtained in Gephi with node size modifications to highlight the major functions areas is shown in Fig. 5.4.

Figure 5.4: The graph representation of Gephi for the topology script in Fig. 5.3

The node colours are used to differentiate function categories. To maintain consistency, the same colour convention that was introduced in the function framework was used. i.e., Avatar Activity functions – green, Land management functions: Region level – red, and Parcel level – brown, Group management functions – yellow, User management functions – purple and Content management function – pink. Middle level functional categories of structural importance are represented in grey. The edge colours were defined to represent the state of the functional interaction, i.e., the usual operational interaction – orange, conflicting or overriding interaction – red and supportive interaction – green. Black edges indicate the structural relationship with the function category. The directed graph edges indicate originating function (source node) and the function that gets affected (target node).

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Figure 5.5 shows the overall network of functions that has been identified. It shows the complexity that the academics and students have to work with OpenSim based MULEs. This overall network is shown here only to provide the holistic impression; it cannot be considered as a usable guidance. However, fortunately, the Gephi interface allows the users to select a function’s ego network with all related interconnections by filtering out the rest.

Figure 5.5: The complex network of OpenSim functions for educational uses

Fig.5.6 shows the filtered ego network of the function Avatar Flying. The legend presents the colours used to highlight the nature of different function interrelationships in the selected network topology. The example of avatar flying management that was discussed previously can be examined with this network; the network shows how the avatar flying can be managed using the available OpenSim functions from different yet interconnected function areas. If we recall the textual descriptions of possible conflicting situations for flying settings on lecture delivery area, the ego network of the fly function can depict all the information in an intuitive manner for an unfamiliar user. Not only does it provide a clear view of the function of interest, but also helps users to select their policy implementations with the context of conflicts/supportive functions for the particular need of management.

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Figure 5.6: The selected Avatar Fly ego-network and the legend for users

Through the Gephi interface, users can easily select the OpenSim functions that they are interested in with the flexibility to define a desired depth of the topology. The developed network topology was designed in a way that by selecting 2 or 3 levels of depth from the selected function node, users can get a complete view of the function behaviour without additional complexities or unrelated information. Section 5.5 presents a study about the tool’s effectiveness and usability for managing an OpenSim based MULE, using an actual educational setup. More details on different ego networks will be presented in the context of relevant Management policies.