INTERFACE DESIGNS

THE ESSEX CORPORATION RECENTLY COMPLETED DEVELOPMENT OF AN AUTOMATED TOOL FOR PREDICTING TIME-ON-TASK AND PROBABILITY OF SUCCESS FOR OPERATORS OF REPROGRAPHIC DEVICES. THE TOOL, CALLED CAPRA, IS CURRENTLY USED BY THE XEROX CORPORATION TO EVALUATE THE INTERFACE CHARACTERISTICS OF PROPOSED COPIERS AND OTHER OFFICE PRODUCTS. CAPRA USES A STATE-SPACE APPROACH TO CHARACTERIZING AN INTERFACE. THE MODEL SIMULATES THE OPERATOR IN ORDER TO PREDICT IMPORTANT METRICS SUCH AS OPERATOR OPTIONS, TASKS AND DECISIONS. IT ALSO IDENTIFIES THE CRITICAL OPERATOR TIME AMONG THE NEARLY INFINITE NUMBER OF PATHS CONNECTING THE TASK START TO THE TASK CONCLUSION. THE SUCCESS OF A STRUCTURAL MODEL LIKE CAPRA FOR SIMPLE OFFICE MACHINE INTERFACES INDICATES A NEED FOR A SIMILAR CAPABILITY FOR THE MORE COMPLEX HUMANMACHINE INTERFACES. THE PURPOSE OF THIS PROPOSAL IS TO SET FORTH A MODELING CONCEPT THAT WILL LEAD TO A GENERAL-PURPOSE PREDICTION AND EVALUATION TOOL FOR THE DESIGN OF COMPLEX HUMAN-MACHINE INTERACTIONS. THE FOUNDATION OF THE PROPOSED CONCEPT RESTS ON THE IDEA OF REDUCING THE MODELED STATE-SPACE BY OVERLAYING IT WITH PATTERNS. THE FORM OF THIS STATE-SPACE REDUCTION TECHNIQUE APPEARS TO BE BY WAY OF THE HIERARCHICAL DECOMPOSITION OF COMPLEX HUMAN-MACHINE INTERFACES AND ESTABLISHING THE RELATIONS BETWEEN INTERFACE FUNCTIONAL PATTERNS AND THE OPERATOR'S MENTAL MODELS.