In FY09, the series of studies from FY08 was followed up with a study on label/ value visual distinction. Of the design features investigated (colon, bolding, space), no significant effects were found. Results from these and prior studies have led to several label guidelines/recommendations on orientation, alignment, and label/value distinction. These recommendations have been or will be documented in several NASA standards and requirements documents.
Readability under Vibration
The results of vibration research in FY08 and FY09 suggested that different forms of symbology were differentially sensitive to vibration effects, with larger, more graphical symbols (such as those found on a primary flight display) more resistant to vibration than alphanumeric symbology. On the basis of this and other considerations, a study (jointly funded by Orion and HRP) investigated the performance impacts of a realistic Orion vibration profile during Thrust Oscillation on a task measuring operator capability to process and integrate information from candidate primary flight display (graphical) symbology. The results of the study were provided to the Orion Project Office, as well as the astronaut office, and formed the basis of a crew-consensus report that broke out crew requirements for maximum vibration during Orion ascents into two components: a maximum vibration level for peaks or bursts set at 0.70 (zero-to-peak), and a sustained vibration level at 0.31 Root Mean Square (RMS).
Effect of vibration on speech intelligibility
Initial work was begun in FY09 to look at speech communication under vibration. In this study, the effect of 0.5 and 0.7 g whole body vibration was evaluated on speech production of words (Diagnostic Rhyme Test word list). Initial observations indicate that, while discrimination of consonants in a two-alternative forced choice paradigm may be only moderately affected, an absolute word identification test will yield low scores. Software and hardware were developed for future testing of speech intelligibility using the Diagnostic Rhyme Test (DRT).
In FY09, a third study in a series was completed to investigate alarms currently in use within NASA space programs, along with some new, candidate alarm tones. Eleven non-crew and 3 crew subjects were asked to rate six candidate alarms in comparison to the current alarm for each of the following categories of alert: Emergency (fire/smoke), Emergency (depressurization), Warning, and Caution. Ratings were also obtained for perceived urgency of the alarm, overall satisfaction with the alarm, and the perceived value of a speech component. The results firmed up a recommended alarm set and indicated that the use of a speech component is preferred by both crew and non-crew.
Cursor Control Device
In FY09, an additional cursor control device evaluation was completed in order to collect data on some new device types, and add to the growing database of cursor control device data. Devices tested included the leading candidate prototype for Orion, as well as some other concepts that had been considered for CxP use. The testing used discrete modes of cursor movement, and participants wore space gloves. Devices tested included the Kensington trackball, a smaller castle-type switch, an F-18 aircraft-derived device, and a rocker switch (Orion candidate). Results showed that the smaller castle-type switch and rocker switch had some of the fastest movement times and lowest frequency of errors. In addition, subjective ratings found the rocker to be most preferred. This study provides important objective performance data to the Orion program, confirming that the rocker switch is a good design.
Cursor Control Device Test Battery
In FY09, the Cursor Control Device Test Battery was further improved by adding a study set-up screen that allows study conductors to set the parameters and the order of the tasks for a study. Usability testing was also conducted on the test battery to improve the user experience with the application.
Electronic Procedures and Fault Management
During FY09, the eye movement data collected as part of the FY07 fault management study were re-analyzed at a more granular level to subdivide originally specified “regions of interest” into more specific “areas of interest” down to the level of specific display symbols. Temporal sequences of fixations to these areas of interest are currently being compared to predictions derived from the application of N-SEEV, a computational model of visual attention that assigns specific weightings to individual display elements on the basis of bottom-up factors (perceptual dimensions such as brightness, contrast, etc.) and top-down factors (derived from dynamic assessments of the task relevance of that particular display element at that specific point in time), and then makes predictions for fixation sequencing based on Luce’s choice rule
Human Performance Modeling
Data analyses of the FY07 Advanced Caution and Warning System (ACAWS) study in support of model development was continued in FY09. Individual fixations from study participants are being analyzed for intent, based on real-time viewing of fixations in conjunction with videotape viewing of the participants.