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IMPRINT Workload Modeling: FY04 and FY05 Work. Raja Parasuraman Cognitive Science Laboratory George Mason University. Tasks—FY04. Review Existing Task Scheduling and Workload Modeling Theory and Research Evaluate Workload Management Strategies in IMPRINT
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IMPRINT Workload Modeling: FY04 and FY05 Work Raja Parasuraman Cognitive Science Laboratory George Mason University
Tasks—FY04 • Review Existing Task Scheduling and Workload Modeling Theory and Research • Evaluate Workload Management Strategies in IMPRINT • Identify and Define Proposed Modifications
Overview and Scope • Outline theoretical foundations for enhancing IMPRINT capabilities in two areas: • Workload modeling • Workload management strategies • Focus on theory, not on IMPRINT tools and models
Overview and Scope (contd.) • Took a “blue sky” approach--considered all possible potential enhancements based on current workload research • Starting points • Mitchell (2000) ARL Technical Report • Wickens (2002) TIES journal article
Descriptors • Theoretical foundation • Implications for IMPRINT • “Seat of the pants” evaluation
Potential Enhancements in Workload Modeling • Updated Implementation of Multiple Resource Theory: Focal vs. Ambient Vision • Cross-Modal Links in Spatial Attention • Time and Intensity Based Models (Hendy’s IP/PCT Model) • MART: Malleable Attentional Resource Theory • Dynamic Workload Modeling • Task Prioritization • Concurrent Task Management (CTM) • Latent Performance Decrements • Task Shifting
Example 1: Cross-Modal Links in Attention • Theoretical Foundation: Although different sensory modalities generally define different resource pools, cross-modal links are present, particularly as a function of common spatial location (Spence & Read, 2003) • Implications for IMPRINT: Revision of workload model, in particular the sensory modality resource type, and the resulting conflict matrix • Initial Evaluation: Implement, given strong background evidence for importance of cross-modal links in spatial attention
Example 2: Time and Intensity Based Models Model (Hendy’s IP/PCT) • Theoretical Foundation: Time to perform a task as a function of time available can be used to predict overall workload, whereas intensity of processing has a lesser effect • Implications for IMPRINT: Revision of workload model, eliminating resource demand and conflict matrix and replacing with a percentage time metric • Initial Evaluation: Do not implement, given that percentage time metrics cannot account for lack of interference from time consuming but minimally resource demanding tasks. Using resource demands and the conflict matrix gives a designer better, more concrete, recommendations pertinent to workstation redesign and therefore more valuable than time-based methods
Tasks—FY05 • Re-examine the mental workload scales in IMPRINT and split the visual workload scale into ambient and focal scales • Benchmark values against verbal descriptors and recommend default values for the resource pair conflict matrix.
Visual Workload • Visual workload is influenced by numerous task, operator, and environmental factors • Current IMPRINT workload algorithm includes a number of these factors • However, current workload algorithm does not distinguish between focal and ambient visual workload
Focal and Ambient Vision • Focal vision: Visual tasks requiring the interpretation of detail (e.g., reading text) • Ambient vision: Visual tasks involving self motion and detection of moving objects (e.g., driving, walking)
Focal Vision Descriptors Scale ValueVisual Scale Descriptor 0.0 No Visual Activity 1.0 Visually Register/Detect (detect occurrence of image) 3.7 Visually Discriminate (detect visual differences) 4.0 Visually Inspect/Check (discrete inspection/static condition) 4.5 Visually inspect multiple displays separated by less than 20o 5.9 Visually Read (symbol) 6.0 Visually inspect/read in low luminance conditions 6.2 Visually inspect multiple displays separated by more than 20o 7.0 Visually scan/search/monitor (continuous/serial inspection, multiple conditions)
Ambient Vision Descriptors Scale ValueVisual Scale Descriptor 0.0 No visual Activity 1.0 Visually monitor for headway maintenance at speeds below 8 mph 1.5 Visually monitor for headway maintenance at speeds above 10 mph 2.7 Visually process/regulate speed of motion 3.7 Visually monitor optic flow when field of view (FOV) is restricted to less than 90o 4.0 Visually locate/align (selective orientation) 5.4 Maintain orientation (i.e., pitch, roll, yaw) during visual tracking/following 6.0 Visually scan/search/monitor (continuous/vigilant monitoring in peripheral vision – high luminance conditions)
Additional Visual Workload Distinctions • Distinguish between focal-verbal, focal-spatial, ambient-verbal, and ambient-spatial processes • Distinguish peripersonal (reaching, grasping, and manipulating objects) and extrapersonal spae (activation of attentional, memory and voluntary motor systems).
Potential Enhancements in Workload Modeling • Updated Implementation of Multiple Resource Theory: Focal vs. Ambient Vision • Cross-Modal Links in Spatial Attention • Time and Intensity Based Models (Hendy’s IP/PCT Model) • MART: Malleable Attentional Resource Theory • Dynamic Workload Modeling • Task Prioritization • Concurrent Task Management (CTM) • Latent Performance Decrements • Task Shifting