helped guide a task analysis of ATIS/CVO functions. In general, network analysis of the information flows that link ATIS/CVO functions can provide a quantitative approach for selecting functions, and their combinations, for a detailed task analysis. Measures of centrality identify important functions that are critical to information flow through the network, thereby reducing the complexity of the task analysis by focusing on important functions. Network analysis also identifies groups of functions, linked by information flows. Task analysis should address these groups to capture important interactions between functions.
By adopting network analysis techniques, it was possible to focus the ATIS/CVO task analysis on central functions and on critical groupings of these functions. The centrality analysis identified highly central functions for which a detailed tasks analysis was performed, whereas the cluster analysis identified groups of functions that should be considered as integrated units in the ATIS design. For example, as part of the task analysis, scenarios were conceptualized to illustrate how future drivers interact with groups of functions identified with the network analysis. Thus, the findings from the network analysis identified meaningful combinations of functions for these scenarios that would have been overlooked by traditional analysis.
In summary, network analysis has the advantage of illuminating important information that may be obscured by numerous interconnections that are shown in flow charts or link diagrams. However, the network analysis requires an adequate listing of functions and information flows linking these functions. Without an accurate representation of the system's functions and their interrelations, results produced by network analysis are meaningless. If these basic concepts are clearly defined, network analysis will capture highly coupled groups of functions and reveal particularly important functions. Detecting functions central to ATIS/CVO, and identifying those that form highly coupled groups, provides a strong basis for a task analysis. A task analysis focused by network analysis will provide a more accurate description of cognitive demands and provide better design guidance.
The functional analysis of ATIS/CVO provides a starting point for considering the task demands associated with accessing and responding to ATIS/ CVO information. A qualitative analysis of ATIS/CVO functions identifies potential human factors issues associated with future systems. The functional analysis can also support quantitative analyses, such as a network analysis of information flows. The network analysis techniques described in this chapter show how a quantitative analysis of information flows among functions can help focus a more detailed analyses, such as task analysis.