Marianne Rudisill

The effects of format in computer-based procedure displays

Two experiments were conducted to investigate display variables likely to influence the effectiveness of computer-based procedure displays. In Experiment 1, procedures were presented in three formats, Text, Extended-Text, and Flowchart. Text and Extended-Text are structured prose formats which differ in the spatial density of presentation. The Flowchart format differs from the Text format in both syntax and spatial representation. Subjects were required to use the procedures to diagnose a hypothetical system anomaly. The results indicate that performance was most accurate with the Flowchart format. Although overall completion times did not differ significantly across formats, the Flowchart format required significantly less time for step implementation. In Experiment 2, procedure window size was varied (6-line, 12-line, and 24-line) in addition to procedure format. In the six line window condition, Experiment 2 replicated the findings of Experiment 1. Procedures in the Flowchart format were completed with greater accuracy than procedures in either of the text formats. As predicted, completion times for Flowchart procedures decreased with increasing window size; however, accuracy of performance decreased substantially. Implications for the design of computer-based procedure displays are discussed.

Automated expert advisor interfaces

Automated expert advisors should provide real time information that allows assessment of the advisors response instead of providing explanation facilities that add to the operators workload. In system control environments, an automated expert advisor applies established rules to system data, arriving at an assessment of the system status. The processing of data results in information being either conserved, reduced, or created. Automated advisors typically reduce or create information thereby reducing operator workload. In a system where the human operator retains final control, the primary goal is for the operator to be able to maintain the system, using the advisors assessment in a manner consistent with the accuracy of that assessment.

The evaluation of cursor control devices for space station freedom

Human-Computer Interface researchers at the Johnson Space Center are faced with the challenge of designing a cursor control device for use in zero gravity so that crewmembers can take full advantage of direct manipulation interfaces. Over the past year, the Crew Interface Analysis Section (CIAS) and the Astronaut Space Station Support Office at the Johnson Space Center in Houston have been working together to generate a research-based recommendation for the design of a microgravity cursor control device for Space Station Freedom.

NASA Johnson Space Center, Human-Computer Interaction

THE LABORATORY The Human-Computer Interaction Laboratory (I-ICIL) was established in 1984 at the NASA Johnson Space Center (JSC) in Houston, TX, to: • Perform applied research examining user interaction with complex computer systems; • Apply the results of this research to the design of spacecraft computer-based workstations and HCIs; and • Serve as a resource in the discipline of humancomputer interaction to support ongoing programs. The HCIL is one of five R&D laboratories within the Crew Interface Analysis Section of the Man-Systems Division in the Space & Life Sciences Directorate.