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HFS Tables of Contents: 87-187-288-188-289-189-290-190-291-191-292-192-293-193-294-194-295-195-2

Proceedings of the Human Factors Society 32nd Annual Meeting 1988-10-24

Fullname:Proceedings of the Human Factors Society 32nd Annual Meeting
Note:Riding the Wave of Innovation
Location:Anaheim, California
Dates:1988-Oct-24 to 1988-Oct-28
Volume:1
Publisher:HFS
Standard No:ISSN 0163-5182; hcibib: HFS88-1
Papers:173
Pages:1-747
Links:Online Proceedings
  1. HFS 1988-10-24 Volume 1
    1. Presidential Address
    2. Aerospace Systems: Pilot Performance and Simulation
    3. Aerospace Systems: Space Station Design and Performance
    4. Aerospace Systems: Displays
    5. Aerospace Systems: Panel
    6. Aerospace Systems: Auditory Spatial Information and Head-Coupled Display Systems
    7. Aerospace Systems: Situation Awareness in Aircraft Systems
    8. Aerospace Systems: Control and Display Issues
    9. Aerospace Systems: Aircrew Station Workload, Design, and Automation
    10. Aerospace Systems: Panel
    11. Aerospace Systems: Workload and Performance
    12. Aging: Panel
    13. Aging: Research on Older People with Applications to Accidents
    14. Aging: Information Processing in Older Adults
    15. Aging: Panel
    16. Communication: Telephony and Video Teleconferencing
    17. Communication: Auditory and Vocal Communication
    18. Communications: Panel
    19. Computer Systems: Approaches to User Interface Design
    20. Computer Systems: Panel
    21. Computer Systems: Interaction Styles
    22. Computer Systems: Panel
    23. Computer Systems: Using On-Line Information
    24. Computer Systems: Hypermedia and Interfaces: Design and Evaluation
    25. Computer Systems: Panel
    26. Computer Systems: User Interface Guidelines
    27. Computer Systems: Invited Address
    28. Computer Systems: Computer Menu and Screen Design
    29. Computer Systems: Prototyping
    30. Computer Systems: Panel
    31. Computer Systems: Computer Users: From Beginner to Expert
    32. Computer Systems: Expert Systems
    33. Computer Systems: Panel
    34. Consumer Products: Designing to Fit the Human
    35. Consumer Products: The Design of Medical Products
    36. Consumer Products: General Session
    37. Educators' Professional: Contemporary Issues in Human Factors Education
    38. Educators' Professional: Professional Aspects of Student-Directed Research: Four Perspectives
    39. Educators' Professional: Panel
    40. Environmental Design: Management and Design of Work Environments
    41. Environmental Design: Evaluating the Impact of Design
    42. Forensics Professional: Forensic Forum: Research for Litigation
    43. Forensics Professional: Panel
    44. Forensics Professional: Human factors Forensic Issues in Slip, Trip, and Fall Litigation
    45. General Sessions: Potpourri
    46. General Sessions: Driver Performance On the Highway of the Future
    47. General Sessions: Human Factors Inside the Automobile
    48. General Sessions: Panel
    49. General Sessions: Shiftwork: Effects on Safety and Productivity
    50. Industrial Ergonomics: What Shall We Do and How Will We Do It? Job and Task Design
    51. Industrial Ergonomics: Let Your Fingers Do the Walking
    52. Industrial Ergonomics: Lift that Load (MMH 1)
    53. Industrial Ergonomics: Tote that Bale (MMH 2)
    54. Industrial Ergonomics: Industrial Potpourri
    55. Industrial Ergonomics: Panel
    56. International Technology Transfer

HFS 1988-10-24 Volume 1

Presidential Address

Designing for Usability: The Next Iteration is to Reduce Organizational Barriers BIBA 1-9
  John D. Gould
This is a draft of the 1988 Human Factors Society Presidential address. A system design philosophy for developing useful, usable systems and products, which we have been advocating since 1980, is first reviewed. The toughest nuts in carrying out the ideas are organizational barriers and resistances. The key ideas in this paper are proposed technical approaches to facilitate organizational changes. The approaches are described in general terms, and their feasibility await successful research outcomes.

Aerospace Systems: Pilot Performance and Simulation

The Effects of Nested Texture on a Landing-Judgment Task BIBA 10-14
  Kimberly A. Reardon
Nested texture can be described as smaller units embedded within larger units or forms within forms (Gibson, 1966). This is reflected in real scenes, e.g., as one moves toward a surface the eye resolves more detail. With the advent of high-fidelity simulators we can now generate a hierarchy of texture patterns that emerge as a function of altitude, but how this affects pilot performance is unclear. This study examined the effect of nested texture with four types of displays in a landing-judgment task. Subjects viewed a simulated landing approach to a runway which stopped in "mid air" and were asked to indicate where they would land if they continued on the same path. Results show that when texture was nested as a function of altitude, performance was not significantly better than when texture was constant throughout the trial. Display type affected performance with subjects perceiving their aimpoint further down the runway as complexity of the texture increased. The landing-judgment study should be followed up with an active-control task before recommendations for visual displays are made.
The Active Control of Altitude over Differing Texture BIBA 15-19
  Lawrence Wolpert
Earlier passive judgment studies showed that detection of loss in altitude was more accurate over texture consisting of stripes parallel to the direction of flight, than over texture consisting of perpendicular stripes or a combination of both, i.e., a square pattern. The current experiment required the participants to actively control and maintain a constant altitude over similar texture in the presence of a pseudorandom windgust. Results corresponded to those of the earlier judgment study with altitude being better controlled when flight took place over parallel texture, than over perpendicular or square texture. Theoretical and applied implications of these findings are discussed.
Incident Analysis of the Effects of Pyridostigmine Bromide BIBA 20-24
  Valerie Gawron; Samuel Schiflett; James Miller; John Ball
The effects of a chemical defense protective drug, pyridostigmine bromide (PB), on inflight aircrew performance were assessed using the Total In-Flight Simulation (TIFS) aircraft. This aircraft was used as both a ground and inflight simulator supplying appropriate control feel, handling characteristics, and cockpit instrumentation for a tactical-transport simulation. Twenty-one C-130 pilots flew two familiarization and four data flights. As part of this study, video recordings of aircrew behavior from preflight through landing were analyzed using an incident analysis technique. Behaviors were grouped in 23 categories including irritability, humor, and accidental activation. The frequencies of occurrences of each of these behaviors by drug (PB or placebo) and crew position (pilot or copilot) are presented as well as an assessment of the utility of the incident analysis technique in drug research.
The Dynamic Seat as an Angular Motion Cuing Device BIBA 25-29
  Robert K. Osgood; Kelly Taylor; Terrence McClurg
The role of advanced motion cuing devices as an alternative to platform motion simulation has been debated for several years. The dynamic seat has been shown to be an effective device for providing task-critical onset motion information on the roll axis, provided that proper attention is given to the drive laws. Since it is difficult to extrapolate the benefit derived from the dynamic seat to an operationally-realistic task environment, the dynamic seat project has initiated a series of studies that lead to motion cuing in a multi-axis aerial refueling task. In this experiment, twelve subjects controlled a compensatory tracking task in roll only, pitch only, and a combined task condition. Operator performance was evaluated between four levels of drive algorithm across axis. Significant differences in tracking performance were found both within axis and between algorithm. In addition, the rank ordering of the treatment means were consistent with previous findings in our laboratory.

Aerospace Systems: Space Station Design and Performance

American and Japanese Control-Display Stereotypes: Possible Implications for Design of Space Station Systems BIBA 30-34
  Clifford K. Wong; John Lyman
This study examined the stimulus-response stereotypes of American (United States citizens) and Japanese (Japanese citizens) subjects on the issue of control-display arrangements. Three questions were investigated. First, do Japanese and Americans operators adhere to the same compatibility principles, e.g., clockwise-for-increase, for certain configurations? Second, do the operators show similar or different responses to certain configurations? Third, are there arrangements in which both populations show strong or weak stimulus-response stereotypes? A paper and pencil test that contained 24 different control-display configurations was administered to 58 American subjects and 58 Japanese subjects, all of whom were right-handed. Out of the 24 configurations, only one elicited similar and statistically significant response stereotypes from American and Japanese subjects. The arrangement that did so emphasized that three compatibility principles (clockwise-for-increase, nearness of control-cursor relation, and scale-side) be in agreement with each other. The results provide initial, albeit speculative, guidelines for the design of control-display systems in NASA's international space station. Since multicultural crews will inhabit the space station for long duration missions, control-display designs which elicit common, consistent, and extremely strong control-movement stereotypes from different cultural populations is a necessity.
Forecasting Crew Anthropometry for Shuttle and Space Station BIBA 35-39
  John Roebuck; Kim Smith; Louis Raggio
Habitation module and Crew Emergency Rescue Vehicle (CERV) designs for the International Space Station to be built by the United States are expected to accommodate a wide range of persons, according to body dimensions predicted for the year 2000. This prediction was aided by the opportunity, which arose in 1985, to check actual Space Shuttle male crew anthropometry, particularly stature, against predictions made circa 1973 and by recently acquired Japanese data. Revised hypotheses discussed herein have been accepted by an Anthropometry Working group as the bases for developing anthropometry requirements that appear in the Man-Systems Integration Standard (NASA-STD-3000), published in 1987. Pleas are made for further research in civilian anthropometry and wider use of anthropometric forecasting.
The Helmet-Mounted Display as a Tool to Increase Productivity during Space Station Extra Vehicular Activity BIBA 40-43
  C. K., Jr. Shepherd
While the debate continues about the safety and applicability of heads-up displays (HUDs) and helmet-mounted displays (HMDs) in the aeronautical environment (as demonstrated in the July, October, and November 1987 issues of the Human Factors Society Bulletin), a voice-controlled HMD is being designed as the core of the information system for the new Space Station Extravehicular Mobility Unit (EMU). This paper describes the human factors issues that suggest the HMD will be a safe and desirable tool for Space Station extravehicular activity (EVA). Also, it briefly outlines a Macintosh-based voice-interactive rapid prototyping system that is being used at the NASA Johnson Space Center for simulating and evaluating the HMD's ability to enhance astronaut productivity in the EVA setting.
Guidelines for the Use of Programmable Display Pushbuttons on the Space Station's Telerobot Control Panel BIBA 44-48
  Mark A. Stuart; Randy L. Smith; Ervette P. Moore
This investigation focused on the establishment of guidelines concerning the use of programmable display pushbuttons (PDPs) on a telerobot control panel. The method taken was to study two groups of subjects performing a simulated Remote Manipulator System (RMS)-like task on micro computer prototypes. Subjects were divided between those who has RMS-simulator experience and those who didn't. The computer prototypes contained simulations of two different control panels -- one which used PDPs and one which used single-function pushbuttons.
   Data analysis revealed that there was a statistically significant (p < 0.05) increase in the number of commands issued in the non-PDP control panel and that subjects rated the PDP control panel significantly higher on two of five scaled questionnaire items. Based on these findings, as well upon the results of responses to open-ended questionnaire items, a preliminary list of guidelines concerning the use of PDPs was developed.
Previous Experience in Manned Space Flight: A Survey of Human Factors Lessons Learned BIBA 49-52
  George O. Chandlee; Barbara Woolford
Three major manned-space programs have been conducted since the mid-1960's: the Apollo, Skylab, and Space Shuttle programs. Each program has contributed significant new data to the field of human factors and to gaining a greater understanding of how humans operate, function, behave, and adapt to the environment encountered in space. This study summarizes relevant human factors data bearing on the lessons learned from previous manned space flights. Our objective is to gather information available from relevant sources, to develop a taxonomy of human factors data, and to provide a centralized source of data that can be used in the future for those individuals involved in the design of manned-spacecraft operations.
   Our results have significance for the establishment and design of manned space vehicles. Methods developed in the collection and archival of human factors data during the course of this study also bear directly on questions of ways in which to systematically compile and characterize human factors data in other areas of research.

Aerospace Systems: Displays

A Comparison of a Stereographic 3-D Display versus a 2-D Display Using an Advanced Air-to-Air Format BIBA 53-57
  John P. Zenyuh; John M. Reising; Scott Walchli; David Biers
This study compared the relative abilities of a stereoscopic 3-D display versus a conventional 2-D display to provide spatial location information. The evaluation was conducted as a part mission, full-task simulation in the context of an air-to-air fighter mission. A dual task paradigm was employed requiring the subjects to acquire situation awareness of their immediate air-to-air environment while simultaneously performing a simple flight tasks. Situation awareness was defined as the ability to visually search a spatial quadrant of the air-to-air situation display relative to the ownship symbol and identify the number of aircraft symbols in a given target group found in that quadrant. The simulated flight task was a two-axis tracking task on a dynamic Head-Up Display format, using a force-stick controller. The subject's response speed and accuracy on the search task and deviations from the given track on the flight task were used as performance measures in this study. The results showed a significant accuracy performance advantage for those formats presented with the stereoscopic 3-D display.
Stereopsis in Cockpit Display -- A Part-Task Test BIBA 58-62
  Thomas C. Way
The benefit of adding retinal disparity to color raster display was tested with two formats. Six pilots flew a tracking task and periodically responded to "failures" in the two represented systems, providing a total of 4320 trials. Response time and error frequency were both reduced when disparity augmented monocular cues to "real world" depth. Response time and error frequency were not affected when disparity was used to make an element of an otherwise flat display more noticeable.
Aircrew Recommendations for Voice Message Functions in Tactical Aircraft BIBA 63-67
  Dennis J. Folds; Roderick A. Beard
Results are presented from a survey of 135 active tactical aircrews regarding use of synthetic voice messages in tactical aircraft. The sample was primarily composed of F-16, F-15, and F-4 pilots. The participants rated 69 existing, proposed, or suggested functions for voice messages in tactical aircraft. Over two-thirds of the participants rated the following functions favorably: Engine Fire, Fuel Low, Oil Pressure, Hydraulic Pressure, Brakes Malfunction, Landing Gear Malfunction, Gear/Flaps Configuration, Low Altitude, Missile Launch, Threat Display, Bingo Fuel, and Joker Fuel. Other functions, applicable to some but not all tactical aircraft, received strong support from the aircrews of the applicable aircraft. The participants' responses to open-ended questions, concerning use of voice messages for checklists and desirable control features for voice message systems, are also summarized.
Effectiveness of Three-Dimensional Auditory Directional Cues BIBA 68-72
  Gloria L. Calhoun; William P. Janson; German Valencia
Natural aural directional cueing in the cockpit should relieve the demands placed on the visual modality, reduce display clutter and alleviate cognitive attention needed to process and extract meaning from coded formats. This experiment compared the effectiveness of three-dimensional (3-D) auditory cues to conventional visual and auditory methods of directing visual attention to peripheral targets. Five directional cues were evaluated: visual symbols, coded aural tone, speech cue, 3-D tone (white noise appearing to emanate from peripheral locations) and 3-D speech (speech cue appearing to emanate from peripheral locations). The results showed significant performance differences as a function of directional cue type in peripheral target task completion time, as well as eye and head reaction time. Results, such as these, will help improve the application of directional sound in operational cockpits.

Aerospace Systems: Panel

Human Factors Design in Special Purpose Workstations for Space Station BIBA 73-74
  Frances E. Mount; W. Gonzalez; B. Houtchens; M. Rudisill; N. Shields; A. Steinberg
The word "Workstations" means different things to different people. In the world of space vehicles command and control is usually the first workstation function that comes to mind. Actually, specialized workstations fall into many categories. This panel will discuss various specialized workstations being developed for the upcoming United States Space Station. As part of the design process the human being, a very integral part of each workstation, is carefully considered.

Aerospace Systems: Auditory Spatial Information and Head-Coupled Display Systems

Auditory Spatial Information and Head-Coupled Display Systems BIBA 75
  Thomas Z. Strybel
Developments of head-coupled control/display systems have focused primarily on the display of three dimensional visual information, as the visual system is the optimal sensory channel for the acquisition of spatial information in humans. The auditory system improves the efficiency of vision, however, by obtaining spatial information about relevant objects outside of the visual field of view. This auditory information can be used to direct head and eye movements. Head-coupled display systems, can also benefit from the addition of auditory spatial information, as it provides a natural method of signaling the location of important events outside of the visual field of view. This symposium will report on current efforts in the developments of head-coupled display systems, with an emphasis on the auditory spatial component.
   The first paper "Virtual Interface Environment Workstations", by Scott S. Fisher, will report on the development of a prototype virtual environment. This environment consists of a head-mounted, wide-angle, stereoscopic display system which is controlled by operator position, voice, and gesture. With this interface, an operator can virtually explore a 360 degree synthesized environment, and viscerally interact with its components. The second paper, "A Virtual Display System for Conveying Three-Dimensional Acoustic Information" by Elizabeth M. Wenzel, Frederic L. Wightman and Scott H. Foster, will report on the development of a method of synthetically generating three-dimensional sound cues for the above-mentioned interface.
   The development of simulated auditory spatial cues is limited to some extent, by our knowledge of auditory spatial processing. The remaining papers will report on two areas of auditory space perception that have received little attention until recently. "Perception of Real and Simulated Motion in the Auditory Modality", by Thomas Z. Strybel, will review recent research on auditory motion perception, because a natural acoustic environment must contain moving sounds. This review will consider applications of this knowledge to head-coupled display systems. The last paper, "Auditory Psychomotor Coordination", will examine the interplay between the auditory, visual and motor systems. The specific emphasis of this paper is the use of auditory spatial information in the regulation of motor responses so as to provide efficient application of the visual channel.
Perception of Real and Simulated Motion in the Auditory Modality BIBA 76-80
  Thomas Z. Strybel
Future head-coupled display systems will include auditory spatial information in order to direct the pilot's attention to critical events in the environment. It is anticipated that such a system will provide dynamic as well as static auditory location information. This report reviews current research in the area of auditory motion perception, particularly as it applies to the development of simulated 3-dimensional auditory space.
Auditory Psychomotor Coordination BIBA 81-85
  David R. Perrott
A series of choice-reaction time experiments are described in which subjects were required to locate and identify the information contained on a small visual target. Across trials, the lateral position of the target was randomly varied across a 240-degree region (+ 120-degrees relative to the subject's initial line of gaze). The vertical position of the target was either fixed at 0-degrees elevation or varied by + 46-degrees. Whether the target was in the visual search period was evident when an acoustic signal indicated the location of the visual target. Auditory spatial information was particularly effective in improving performance when the position of the target was varied in elevation or the target was located in the rear field. The current results support the notion that the auditory system can be used to direct eye-head movements toward a remote visual target.
A Virtual Display System for Conveying Three-Dimensional Acoustic Information BIBA 86-90
  Elizabeth M. Wenzel; Frederic L. Wightman; Scott H. Foster
A three-dimensional auditory display could take advantage of intrinsic sensory abilities like localization and perceptual organization by generating dynamic, multidimensional patterns of acoustic events that convey meaning about objects in the spatial world. Applications involve any context in which the user's situational awareness is critical, particularly when visual cues are limited or absent; e.g., air traffic control or telerobotic activities in hazardous environments. Such a display would generate localized cues in a flexible and dynamic manner. Whereas this can be readily achieved with an array of real sound sources or loudspeakers, the NASA-Ames prototype maximizes flexibility and portability by synthetically generating three-dimensional sound in realtime for delivery through headphones. Psychoacoustic research suggests that perceptually-veridical localization over headphones is possible if both the direction-dependent pinna cues and the more well understood cues of interaural time and intensity are adequately synthesized. Although the realtime device is not yet complete, recent studies at the University of Wisconsin have confirmed the perceptual adequacy of the basic approach to synthesis.
Virtual Interface Environment Workstations BIBA 91-95
  S. S. Fisher; E. M. Wenzel; C. Coler; M. W. McGreevy
A head-mounted, wide-angle, stereoscopic display system controlled by operator position, voice and gesture has been developed at NASA's Ames Research Center for use as a multipurpose interface environment. This Virtual Interface Environment Workstation (VIEW) system provides a multisensory, interactive display environment in which a user can virtually explore a 360-degree synthesizer or remotely sensed environment and can viscerally interact with its components. Primary applications of the system are in telerobotics, management of large-scale integrated information systems, and human factors research. System configuration, research scenarios, and research directions are described.

Aerospace Systems: Situation Awareness in Aircraft Systems

Situation Awareness in Aircraft Systems BIBA 96
  Mica R. Endsley
The ability of the pilot to maintain situation awareness (SA) is recognized in the aerospace community as crucial to mission success and survivability. Establishing and maintaining aircrew situation awareness must become a predominant design goal in the development of future aircraft systems. Little work has been done in the scientific community, however, to definitize, explore and measure this important cognitive construct, allowing cockpit design efforts to emphasize that goal. This symposium will focus on establishing a meaningful dialogue and literature base on situation awareness and encouraging future research in requisite directions.
   The objectives of the symposium are to (1) present current research directed at defining the situation awareness construct, investigating the interactions of SA with other cognitive functions, and developing a methodology for measurement, and (2) present current research efforts in designing for situation awareness which have utilized a scientific approach to establishing and evaluating the design. The symposium will be equally divided between these two goals. The first two papers explore the SA construct and provide a comprehensive discussion in the areas of definition and measurement. The last two papers provide meaningful insight into the issues involved in designing for SA., discussing that process as well as presenting research on the effects of a display design effort and an expert systems implementation effort on situation awareness. All together, this symposium seeks to begin the exploration of an untapped area for human factors research and development.
Design and Evaluation for Situation Awareness Enhancement BIBA 97-101
  Mica R. Endsley
Situation awareness (SA) is an important component of pilot/system performance in all types of aircraft. It is the role of the human factors engineer to develop aircraft cockpits which will enhance SA. Research in the area of situation awareness is vitally needed if system designers are to meet the challenge of providing cockpits which enhance SA. This paper presents a discussion of the SA construct, important considerations facing designers of aircraft systems, and current research in the area of SA measurement.
A Theory of Situation Assessment: Implications for Measuring Situation Awareness BIBA 102-106
  Martin L. Fracker
Measures of pilot situation awareness (SA) are needed in order to know whether new concepts in display design help pilots keep track of rapidly changing tactical situations. In order to measure SA, a theory of situation assessment is needed. In this paper, I summarize such a theory encompassing both a definition of SA and a model of situation assessment. SA is defined as the pilot's knowledge about a zone of interest at a given level of abstraction. Pilots develop this knowledge by sampling data from the environment and matching the sampled data to knowledge structures stored in long-term memory. Matched knowledge structures then provide the pilot's assessment of the situation and serve to guide his attention. A number of cognitive biases that result from the knowledge matching process are discussed, as are implications for partial report measures of situation awareness.
Information Transfer from Intelligent EW Displays BIBA 107-110
  Marion P. Kibbe
Dual-task performance and recalled information data were used to compare levels of situational awareness from manual and automated threat recognition tasks. Dual-task performance reflected the effects of monitoring an automated system while tracking. There were no differences in information transfer as a function of automation.
The Design of a Tactical Situation Display BIBA 111-115
  Gilbert G. Kuperman; Denise L. Wilson
This research and development effort was directed to the design and proof-of-concept demonstration of a dynamic tactical situation display (TSD) applicable to an advanced conceptual bomber crew system. The TSD provides a primary source of mission pacing and situational awareness information in the Strategic Avionics Battle-Management Evaluation of the Armstrong Aerospace Medical Research Laboratory. Four levels of situational awareness information are supported by SABER: (1) conventional paper products, (2) digitized (softcopy) versions of these hardcopy materials, (3) dynamic graphic representation of horizontal situation, and (4) horizontal situation display with digital terrain elevation and cultural feature underlay. The TSD described in this paper is being applied in the SABER simulation facility to support research directed to the optimization of the bomber crew system in the context of future mission requirements.

Aerospace Systems: Control and Display Issues

Comparing Oculometer and Head-Fixed Reticle with Voice or Switch for Tactical Display Interaction BIBA 116-120
  Christopher C. Smyth; Mary E. Dominessy
An experiment with 15 U.S. Army enlisted military subjects was conducted to compare the performance of an oculometer, head-fixed reticle, and touch panel for data entry on a generic tactical air combat display. The subjects used voice or switch to designate data items on the display that were selected with the oculometer or fixed reticle. The touch panel was included as a standard data entry device. Statistical analysis showed a significant difference in performance for the five configurations at the .0001 level. The reticle/switch, oculometer/switch, and touch panel are significantly faster than the reticle/voice, which in turn is significantly faster than the oculometer/voice. The reticle methods are faster than the oculometer methods. The switch action is faster than voice entry. The touch panel is twice as accurate as the other methods, all of which have about the same spatial accuracy whether oculometer or reticle, voice or switch. However, the oculometer/voice has nearly twice as many selection errors as the other methods.
Determination of a Gain-Function Relating Control Force to Cursor Velocity BIBA 121-125
  Stephen Rauch
F-14D fighter pilots will have the capability to use cursor control to designate symbols and pushbutton legends on multifunction displays (MFD). Since operators often will be required to slew and designate a target symbol or pushbutton legend in diverse environments, it is important to determine a control system gain, the relationship between response magnitude (in this case, force) and amount of cursor movement or velocity, that will enhance performance during slewing/designate tasks. The purpose of this study was to evaluate six different gain-functions analyzing speed, accuracy, and subjective comments, to determine an optimal gain-function relating control force to cursor velocity. Trend indicated that Gain-function 1, the gain-function with the lowest mean pixel error and fastest mean acquisition time, would be the best gain-function to use in the F-14D aircraft.
Variable Magnification Considerations for Airborne, Moving Map Displays BIBA 126-129
  Charles P. Allen
Color moving-map displays are increasingly being recommended for inclusion in the crewstations of modern aircraft. Research evaluates display magnification requirements for color moving-map display systems for two map scale uses, three map scales and two lighting conditions. Results show significant differences in magnification requirements for different map uses, map scales and lighting conditions. Results suggest the need for new guidelines.
A Model of Electronic Map Interpretation BIBA 130-134
  Anthony J. Aretz
This paper describes an experiment that provides data for the development of a cognitive model of pilot flight navigation. The model views navigation as a process involving the alignment of mental images with the perceptual view out of the cockpit. The data support a three stage model: 1) the perceptual encoding of the map display, 2) mental rotation of the mental image, and 3) comparison of the image to the environment. The variables that significantly influence the processes embodies in the model in decreasing importance are: speed of processing, display sequencing, map complexity, and rotation angle of the map. The model can be used as a preliminary computational tool in predicting the navigational component of pilot situational awareness.

Aerospace Systems: Aircrew Station Workload, Design, and Automation

A Frame-Based Mission Decomposition Model BIBA 135-139
  Gilbert G. Kuperman; William A. Perez
This paper presents the results of a mathematical modeling (computer simulation) effort that applied frame-based, data processing constructs, originally developed and applied in the context of artificial intelligence, to the decomposition of a complex Air Force bomber mission. The model was written in LISP to facilitate the development of a concurrent processing environment in which to simulate the simultaneous occurrence of multiple external events/crew tasks. The model simulated a four hour segment of a strategic mission scenario. Two distinct crew complements, four-man and two-man, together with their respective levels of aircraft avionics automation, were represented during a proof-of-concept demonstration. The model provided measures of resource (crew and "black box") utilization, presumed to correlate to "workload," at different levels of specificity. These measures were used to identify crew task "choke-points" (large queue sizes, task interrupts) and to evaluate the effects of automation.
Using Mission Decomposition Tools in Advanced Cockpit Applications BIBA 140-144
  Michael N. Stollings; Richard E. Edwards; William L. Rankin
This paper describes an interactive, computer-based Mission Decomposition Tool (MDT) developed as part of the Cockpit Automation Technology Program sponsored by the Air Force System Command's Human Systems Division. The purpose of this tool is to improve the efficiency of the crewstation design process. Specific activities supported by the MDT include generation and decomposition of Air-to-Air and Air-to-Ground mission scenarios; generation of mission event timelines; and post-flight analysis. Mission generation/decomposition involves the laydown of maps, map features (streams, roads, etc), threats, targets and waypoints. The mission event timeline is generated automatically when a mission is flown and may be edited to ensure that unique mission activities are included. Post-flight analysis options include plots of threat exposure, terrain masking, terrain following, terrain clearance, discrete mission events, and aircraft performance data. The MDT strengthens the connection between analysis and test and evaluation activities in the areas of mission planning, pilot briefing, simulation set-up, performance assessment, and post-flight analysis.
Mental Models: A Fifth Paradigm? BIBA 145-149
  Thomas J. Higgins; Mark H. Chignell
This paper describes ongoing research concerned with the development of a mental model for human pilots performing the final phases of an instrument landing approach. The results of three experiments are reported. The first experiment (reported more extensively by Higgins and Chignell, 1987) was used to select the parameters used in the subsequent experiments. The second experiment tested the validity of collecting verbal protocols during simulated instrument landings, while the third experiment studied the behavior of pilots when a wind condition, and additional information, are introduced to the task. In the third experiment, theoretically useful information was provided by an experimenter simulating the advice that would be given by an expert system. However, the results of this experiment showed that information hurt, rather than helped, performance. Verbal protocols were also collected in the three experiments. The second experiment tested the effect that collecting verbal protocols had on pilot performance on the task. Although some perturbation of task performance was observed, think aloud protocols were found to give satisfactory results, while the newly developed method "division of labor" (Higgins and Chignell, 1987) was found to be unsatisfactory as currently used (without specific training of each pilot-copilot pair).
Transport Pilot Workload: A Comparison of Two Subjective Techniques BIBA 150-154
  Vernol Battiste; Michael Bortolussi
Although SWAT and NASA-TLX workload scales have been compared on numerous occasions, they have not been compared in the context of transport operations. Transport pilot workload has traditionally been classified as long periods of low workload with occasional spikes of high workload. Thus, the relative sensitivity of the scales to variations in workload at the low end of the scale were evaluated. This study was a part of a larger study which investigated workload measures for aircraft certification, conducted in a Phase II certified Link/Boeing 727 simulator. No significant main effects were found for any performance-based measures of workload. However both SWAT and NASA-TLX were sensitive to differences between high and low workload flights and to differences among flight segments. NASA-TLX (but not SWAT) was sensitive to the increase in workload during the cruise segment of the high workload flight. Between-subject variability was high for SWAT. NASA-TLX was found to be stable when compared in the test/retest paradigm. A test/retest by segment interaction suggested that this was not the case for SWAT ratings.
Techniques of Subjective Assessment: A Comparison of the SWAT and Modified Cooper-Harper Scales BIBA 155-159
  Kevin J. Kilmer; Robert Knapp; Charles, Jr. Burdsal; Robert Borresen; Robert Bateman; Don Malzahn
This study examined two subjective mental workload assessment scales, the Subjective Workload Assessment Technique (SWAT) and the Modified Cooper-Harper (MCH) Scale. The purpose of this study was to make a direct comparison of the two scales in order to determine if both scales were equally sensitive to changes in task difficulty hence, workload. Forth introductory psychology non-aviator students were trained on an aviation like psychomotor dual-task experiment. Task difficulty was manipulated by presenting the subjects with three (low, moderate, high) levels of wind gust disturbance (turbulence) and requiring them to maintain an assigned altitude and airspeed, while responding to a visual choice reaction time secondary task. The data was analyzed using multivariate statistics. The results of the analysis found that both the SWAT and MCH were sensitive to changes in task difficulty. However, the MCH appeared to be less sensitive than the SWAT.

Aerospace Systems: Panel

Human Factors Issues in Aircraft Maintenance BIBA 160-161
  Anthony E. Majoros
Aircraft present significant challenges to the people who maintain them. Time pressure, the complexity of aircraft systems, the need to adhere to minute detail, and cramped working spaces generally interact to create a difficult work setting. Due to the cognitive, biodynamic, and endurance demands of this work, human capacities and limitations are important variables in civil and military aviation maintenance. The critical nature of these variables is indicated in a variety of emerging research issues.

Aerospace Systems: Workload and Performance

Workload Evaluations of a Stereo 3-D Computer-Generated Pictorial Primary Flight Display BIBA 162-163
  Mark Nataupsky; Alan T. Pope; Mary L. McManus; Daniel X. Burdette
With the advent of digital avionics and cathode ray tube (CRT) displays, the use of computer-generated flight displays has become increasingly prevalent in both commercial and military cockpits. These flight displays, however, typically are renditions of the electromechanical displays that are being replaced. But there is great potential for display enhancement and integration through formats such as pictorial, real-world formats that could enhance situation awareness and reduce crew workload.
   This study had as its objective the exploration of workload measures in conjunction with a larger study of a computer-generated, integrated pictorial primary flight display presented in stereo and non-stereo modes. Of interest in the workload aspect of the study was the ability to differentiate workload attendant with use of several versions of the pictorial display having alternate implementations of 3-D symbology cues, presented in stereo and non-stereo modes. Both physiological and subjective measures were used with a pilot-in-the-loop flight simulation task. The physiological measure was visually-evoked brain wave potentials; the subjective measure was the Subjective Workload Assessment Technique (SWAT) (Reid, Shingledecker, and Eggemeier, 1981a and Reid, Shingledecker, Clark, and Eggemeier, 1981b).
   A number of physiological studies have demonstrated the relationship of the P300 component of event-related brain potentials to controlled stimuli (e.g., Zacharias, 1988). Further physiological studies by Kramer, Donchin, and Wickens (In Press) have shown that the amplitude of the P300 can be related to levels of pilot workload. The SWAT is a validated measure of subjective workload. Nataupsky and Abbott (1987) used SWAT to differentiate levels of a pilot's perception of workload in a piloted simulator flight task.
   The workload portion of the study was accomplished in the following manner. Pilots were initialized on the nominal flight path (as defined within the pictorial display). After approximately 2 seconds, they were suddenly offset to one of eight positions. The sudden display shift was the stimulus to which pilots had been asked to respond with control inputs and was the trigger for the visually-evoked response. Thus, contrary to previous studies conducted at Langley which used secondary tasks to elicit evoked potentials, this study had the primary task as the trigger for the evoked response. The pilots' task was to make the initial pitch and/or roll input necessary to correct back to the nominal flight path. Data was collected on 216 trials for each of eight Air Force pilots. Analysis of the workload data is in progress.
A Fuzzy Set Analysis of Skill, Rule and Knowledge-Based Workload BIBA 164-167
  Neville Moray; Eugene Kruschelnicky; Paul Eisen; Laura Money; I. B. Turksen
Using fuzzy measures of task difficulty the effect of combining different aspects of a task on the overall task workload was explored. A complete set of combination rules is provided, of the general form "if the skill-based component is slightly difficult, the rule-based moderately difficult, and the knowledge-based slightly difficult, then the task as a whole is moderately difficult." Fuzzy linguistic variables provide an adequate systematic framework for such combined judgments.
TASKILLAN: A Simulation to Predict the Validity of Multiple Resource Models of Aviation Workload BIBA 168-172
  Christopher D. Wickens; Kelly Harwood; Leon Segal; Inge Tkalcevic; Bill Sherman
The objective of this research was to establish the validity of predictive models of workload in the context of a controlled simulation of a helicopter flight mission. The models that were evaluated contain increasing levels of sophistication regarding their assumptions about the competition for processing resources underlying multiple task performance. Ten subjects performed the simulation which involved various combinations of a low level flight task with three cognitive side tasks, pertaining to navigation, spatial awareness and computation. Side task information was delivered auditorily or visually. Results indicated that subjective workload is best predicted by relatively simple models that simply integrate the total demands of tasks over time (r = 0.65). In contrast, performance is not well predicted by these models (r < .10), but is best predicted by models that assume differential competition between processing resources (r = 0.47). The relevance of these data to predictive models and to the use of subjective measures for model validation is discussed.
Stress and Pilot Judgement: An Empirical Study Using MIDIS, a Microcomputer-Based Simulation BIBA 173-177
  Christopher D. Wickens; Alan F. Stokes; Barbara Barnett; Fred Hyman
This report presents an information processing framework for predicting the effects of stress manipulations on pilot decision making. The framework predicts that stressors related to anxiety, time pressure, and high risk situations will restrict the range of cue sampling and reduce the capacity of working memory, but will not affect decisions that are based upon direct retrieval of knowledge from long term memory. These predictions were tested on MIDIS, a microcomputer-based pilot decision simulator. Performance on a series of 38 decision problems was compared between ten subjects in a control group and ten subjects who had performed under conditions of noise, concurrent task loading, time pressure, and financial risk. The results indicated that the stress manipulation significantly reduced the optimality and confidence of decisions. The manipulations imposed their greatest effect on problems that were coded high on spatial demand and on problems requiring integration of information from the dynamic instrumental panel. The effects of stress were relatively independent of problem demands associated with working memory and with the retrieval of knowledge from long term memory.
An Empirically Validated Task Analysis (EVTA) of Low Level Army Helicopter Operations BIBA 178-182
  Margaret T. Shaffer; Keith C. Hendy; Lou R. White
A computer-based Empirically Validated Task Analysis (EVTA) of Canadian Forces light observation helicopter operations was conducted from video records of cockpit activity gathered during flight. The task analysis was performed in order to provide data for function analysis and workload prediction studies in support of the Canadian Forces Light Helicopter replacement project. Observable behaviors were categorized according to the type of activity involved and communications were analyzed for content, agencies involved, and relevance to the crew's task. The results of this study indicate that data gathered from a controlled test environment can differ considerably from those obtained in operational settings and that miniature video cameras can be useful in obtaining information from environments which hitherto may have been inaccessible to all but operational personnel.

Aging: Panel

Programs in Human Factors and Aging: National Research Council and National Institutes on Aging BIBA 183
  Arnold M. Small; Sara J. Czaja; Robin Barr; Richard W. Pew
Within the last year, these two Federal agencies have developed insights, research needs and programs related to human factors and aging. These will be described and their significance assessed by the panel speakers and discussants. Audience participation is invited.
The Wave of Innovation for an Aging Society: Enhancing Independent Living BIBA 184
  Susan Meadows
"The Wave of Innovation for an Aging Society" encompasses serious concerns for all who envision an independent, healthy, and functioning society in the future. By the year 2000, one in five Americans will be over the age of 55. In order to address the challenges facing society for continued functioning, technological innovations of today must be explored as viable strategies. This panel will discuss the application of human factors principles in safety, health care, and technology toward the enhancement of work and independent living for the future.

Aging: Research on Older People with Applications to Accidents

Safety of Older Drivers: A Study of Their Over-Involvement Ratio BIBA 185-188
  Paul K. Verhaegen; Katrien L. Toebat; Luc L. Delbeke
An analysis of reports of 660 two-car collisions from the records of an insurance company showed that car drivers of 60 years old and older are more apt to be considered liable in an accident than younger drivers. A comparison of accidents for which older drivers (60 yrs. and over) are responsible with accidents for which younger drivers (30-39 yrs.) are responsible showed that the former have problems of perception and decision making and that the latter have problems with speed.
An Information Processing Approach to the Problem of Medication Noncompliance among Older Adults BIBA 189-193
  Jill Annette Strawbridge
A preliminary experiment was conducted to investigate a cognitive processing explanation for prescription drug noncompliance among older adults. The experimental construct tested was that the dynamic underlying the misinterpretation of many medicine directives is directly related to the number of mental operations that each format requires in order to answer a specific question about dosage information. Reaction times and error rates were found to follow a pattern of results which supports the hypotheses for both older and younger adults. Increasing the number of mental operations was found to be most detrimental to the performance of adults age 75 years and older.
Everyday Sound Perception and Aging BIBA 194-197
  James A. Ballas; Mark E. Barnes
Age related hearing loss is extensively documented in both longitudinal and cross-sectional studies but there are no direct studies of the ability of older persons to perceive everyday sounds. There is evidence suggesting some impairment. Vanderveer (1979) observed that older listeners had difficulty interpreting environmental sounds but did not report any performance data. Demands imposed by the stimulus properties of this type of sound and by the perceptual and cognitive processes found to mediate perception of this sound in college-aged listeners may present difficulty for older listeners. Forty-seven members of a retired organization were given a subset of sounds that had been used in previous identification studies. Identification data for the same set of sounds had been previously obtained from high school and college students (Ballas, Dick, & Groshek, 1987). The ability of the aged group to identify this set of sounds was not significantly different from the ability of a student group.
   In fact, uncertainties were closely matched except for a few sounds. Directions for future research are discussed.

Aging: Information Processing in Older Adults

Age-Related Effects of Stimulus-Specific Context on Perceptual Learning BIBA 198-202
  Wendy A. Rogers; Arthur D. Fisk
The focus of the present study was the investigation of age-related differences in perceptual learning under conditions of consistent mapping (CM), varied mapping (VM), and context-specific training. Context-specific training involved conditions where specific target and distract sets were paired consistently within a condition but were inconsistent across conditions. Eight young (mean age 25) and eight old (mean age 67) subjects participated for 8000 trials of training and 3200 trials of various transfer conditions. The transfer conditions were designed to ascertain the extent to which the subjects had automatized their performance in each of the training conditions. The training results yielded significant differences between young and old adults only under CM training. Performance in the context conditions for young adults mimicked that of the old subjects in the CM condition. The training results suggest that manipulations which disrupt the development of attention-calling strength of stimuli lead to equivalent performance for young and old adults. The transfer results provide similar information. It is proposed that the ability to "strengthen" target information is disrupted in older adults. Based on our previous and the present findings, processing principles are presented which outline important differential considerations for training young and/or older adults.
Effects of Age, Gender, Activation, Stimulus Degradation and Practice on Attention and Visual Choice Reaction Time BIBA 203-207
  Max Vercruyssen; Michael T. Cann; Joan M. McDowd; James E. Birren; Barbara L. Carlton; Jane Burton; P. A. Hancock
This paper presents research conducted by the authors and others investigating the interaction of a variety of variables which are presumed to affect reaction time in hopes of obtaining much needed information on factors influencing age effects on attention and information processing. Reported is progress to date on an experiment which shows that the effects of age on central nervous system speed, as measured by visual choice reaction time, depends on many factors, including the gender, neural activation level, and skill of the subject as well as the stimulus quality and type of reaction task employed.
Effects of Age and Practice on Attention and Stages of Information Processing using CRT with Fixed and Variable Foreperiods BIBA 208-212
  Barbara L. Carlton; Max Vercruyssen; Joan M. McDowd; James E. Birren
The results of previous investigations have found conflicting results on the locus of age-related slowing of reaction time using Additive Factors Method (Sternberg, 1969). This experiment was conducted to examine the differential effects of Additive Factors Method task manipulations using both fixed and variable foreperiod conditions with practice preceding a second day replication to quantify the interaction of these effects with skill. The results show that (1) practice is a major confounding for research involving RT tasks, (2) the locus of age effects may lie in the later response selection stage of processing, and (3) the effects of aging, practice and intra-task factors depend on the response-stimulus interval characterizing the RT task. This research has implications for improving research methodologies and understanding the nature of age-related slowing in central nervous system functions.

Aging: Panel

The Older and Disabled Population: Forensic Issues in Accidents and Age Discrimination BIBA 213-214
  David B. D. Smith; Gary D. Sloan; Jefferson M. Koonce; Daniel A. Johnson; Martin Levine
Both the forensic and aging domains have emerged in the last 10 years, as growing areas in human factors. These two areas are likely to find more and more issues of common concern as the U.S. population ages. There were some 50.2 million Americans age 55 and over in 1984, or one-fifth of the population. About one-half of this number were over the age of 65. In the next 30 years, the over 55 age population will have grown to one-third of all Americans, with persons over 65 being one-fifth of the population. These demographic trends, plus an elderly cohort with possibly different values about the right to legal redress, suggest age will become an increasingly relevant issue for the forensic specialist in human factors.
   The purpose of this panel session, jointly sponsored by the Aging and Forensic Tech Groups, is to address issues related to liability, age discrimination and functional age assessment.

Communication: Telephony and Video Teleconferencing

Designing Speech Displays for Telephone Information Systems BIBA 215-218
  David W. Herlong; Beverly H. Williges
This study used a computer-driven telephone information system as a real-time human-computer interface to simulate applications where synthetic speech is used to access data. Subjects used a telephone keypad to search through an automated department store database to locate and transcribe specific information messages. Because speech provides a sequential and transient information display, users may have difficulty navigating through auditory databases. One issue investigated in this study was whether the alternate use of male and female voices to code different levels of the database would improve user search performance. Other issues investigated were the basic intelligibility of these male and female voices as influenced by different levels of speech rate. All factors were assessed as functions of search or transcription task performance and user preference. Analysis of transcription accuracy, user search efficiency and time, and subjective ratings revealed an overall significant effect of speech rate on all groups of measures but no significant effects for voice type or coding scheme. Results were used to recommend design guidelines for developing speech displays for telephone information systems.
Novice-Expert Differences in the Cognitive Representation of System Features: Mental Models and Verbalizable Knowledge BIBA 219-223
  Kathy A. Hanisch; Arthur F. Kramer; Charles L. Hulin; Robert Schumacher
The relationship between users' mental models and their verbalizable knowledge of a system were investigated in a field study. Trained and untrained users of a new phone system rated the similarity of use of nine phone features. Their ratings of the features were used in a multidimensional scaling technique and hierarchical cluster analysis to obtain their mental models of the system. Individuals' ratings of features on unidimensional scales about the use of the features and scores obtained on a knowledge test were reflected in their mental models. Mental models of the two novice groups' were very similar except for the perception of one feature; it was more accurately depicted in the mental model of users who attended than those who did not attend a training program. Trainers' and system designers' mental models of the phone system were evaluated to determine an "appropriate" expert mental model. A comparison of the "expert" mental model to the novices' mental models suggested that several features were inaccurately perceived by the novices. Using the discrepancies between the expert and novices' mental models to design training programs for systems is discussed. A novel way to design or redesign systems based on novices' mental models of systems is proposed.
Design and Testing of a Facility for Two-Way Video Teleconferencing BIBA 224-228
  William H. Cushman; Robert Derounian
This report describes the design and testing of a facility for two-way video teleconferencing. The design process began by developing and distributing a survey to assess the needs of potential users, to develop a "user profile" for these individuals, and to determine their willingness to consider video teleconferencing as an alternative to "in person" meetings. In addition to the survey, design data were obtained from the human factors literature, site visits, interviews with users of existing video teleconferencing rooms, and rapid prototyping and user testing of alternative designs. Construction of the facility has been completed, and over 200 users have been trained to use the equipment. User reaction has been very favorable, with a majority of users expressing a desire to use the facility again.
When Lips and Voice Disagree: Determining the Practical Limits and Consequences of Visual-Auditory Asynchrony BIBA 229-231
  Lawrence M. Paul
This talk explores the limits and costs of the visual-auditory asynchrony that occurs in video teleconferencing systems using separate transmission paths for the video and audio signals. After a brief review of video teleconferencing, the special problem of asynchrony in two-path systems is developed, and the small quantity of directly applicable research is reviewed. The two human factors questions which needed to be answered were: 1) What are the "just tolerable" limits of asynchrony?, and 2) What is the cost in terms of misperceptions of living with asynchrony? The experiment had nine participants determine their "just tolerable" asynchrony limits with video first and with audio first, and their "perfect synchrony" point. The average "just tolerable" limit with video preceding audio was 104 msec with a small variability. Very surprisingly, the "just tolerable" limit with audio first was at least 160 msec. Thus, common wisdom not withstanding, it is apparently easier to live with the audio preceding the video. Research is currently underway to measure the cost of living with asynchrony. MacDonald and McGurk, 1978, found that particular combinations of spoken and seen syllables led to the perception of completely different syllables. The present research extends MacDonald and McGurk' work to word pairs with first syllables from the corresponding special syllable pairs to determine if living with asynchrony necessarily means living with misperceptions in addition to just simple "annoyance".

Communication: Auditory and Vocal Communication

The Effects of Recognition Accuracy and Vocabulary Size of a Speech Recognition System on Task Performance and User Acceptance BIBA 232-236
  Sherry P. Casali; Robert D. Dryden; Beverly H. Williges
The purpose of the present study was to determine the effects of recognizer accuracy and vocabulary size on system performance of a speech recognition system. Subjects, ranging in age from 20 to 55 years, performed a data entry task using a simulated speech recognizer which simulated three accuracy levels and three levels of available vocabulary. Task completion times and subjective measures of acceptability were recorded. Results indicated that the accuracy level at which the recognizer was performing significantly influenced the task completion time and the user's acceptability ratings. Vocabulary size also significantly affected task completion time, however, its affect on the acceptability ratings was negligible. Older subjects in general required longer times to complete the tasks, however, they consistently rated the speech input systems more favorably than the younger subjects.
Field Study of Communication and Workload in Police Helicopters: Implications for AI Cockpit Design BIBA 237-241
  Charlotte Linde; Robert J. Shively
This paper reports on the work performed by civilian helicopter crews, using audio and video recordings and a variety of workload measures (heart rate and subjective ratings) obtained in a field study of public service helicopter missions. The number and frequency of communications provided a significant source of workload. This is relevant to the design of automated cockpit systems, since many designs presuppose the use of voice I/O systems. Fluency of communications (including pauses, hesitation markers, repetitions, and false starts) furnished an early indication of the effects of fatigue. Three workload measures were correlated to identify high workload segments of flight, and to suggest alternate task allocations between crew members.
Parameters of Information-Rich Auditory Announcements BIBA 242-246
  R. M. Mulligan; W. B., II Whitten; Y-C. Tsao
An investigation of factors influencing the effectiveness of brief (< 5 minutes), information-rich auditory announcements began with a literature review that identified several potentially important variables. Next, an initial experiment examined the relative importance of some of these variables in the context of a prototype audiotex application. The results of this study allowed tentative conclusions to be made about the influence of several announcement parameters including duration, speech rate, amount of information, and linguistic complexity, on memory and preference for announcements. Finally, a follow-up experiment focused on the speech rate variable and on the use of time-compressed speech to increase the efficiency of information acquisition. Results of this study indicated that although learning efficiency can be significantly increased by accelerating speech to 1.5x normal rate, listeners prefer a speech rate closer to normal.
Causal Uncertainty and Contextual Cues in the Recognition of Environmental Sounds BIBA 247-251
  R. Timothy Mullins
Previous research has supported the hypothesis that the recognition of environmental sounds is complicated by uncertainty caused by the number of potential causes of that sound. In natural settings, contextual cues often help to specify the source of ambiguous sounds. This proposes the question of whether contextual cues can overpower auditory information to establish causal certainty of otherwise ambiguous environmental sounds. A study was conducted to examine this possibility. The results showed that contextual cues could have powerful effects on the judgement of the causal event of auditory stimuli. This result could have implications for tasks which are dependent on discrimination of auditory events. In particular, if a discrimination between two auditory events is critical, the effects of auditory context suggest that two or more possible alternatives might be indistinguishable in context and should be isolated for purposes of contrast.

Communications: Panel

Telecommunications in the 1990s: Human Factors Issues for the Information Age BIBA 252-253
  Robert W. Root; Charles Grantham; Thomas Landauer; Wendy Mackay; Robert McNinch
Advances in technology are revolutionizing the communications industry. Optical fiber, computer-controlled switches, software-defined services, digital communications, and integrated services networks will soon deliver high-speed broadband communications and information services to individual homes and businesses. The next decade will bring impressive changes in the power, complexity and range of services offered through what we think of as the "telephone system". The technology is inexorably advancing, with or without the blessing and guidance of the human factors community.
   The main purpose of this panel is to call attention to the human factors implications of the "network of the future". A major aspect of this future network will be a blurring of the distinction between computation and communications due to the integration of voice and data networks (as in ISDN). This integration will have several important consequences. First, the notion of "communications" activities will be broadened to include not only synchronous human-human interaction but also asynchronous (e.g., electronic mail), multiparty, and human-machine interaction (as in information retrieval). Second, personal computers will increasingly be used and viewed as communications devices as well as computational machines. Third, "intelligent" networks will play an increasingly important role as mediators of human-human and human-machine interaction rather than acting simply as passive transport systems.
   These developments may be important for the practice of human factors. At the very least, they imply a merging of the concerns of telecommunications with human-computer interaction research. For example, designing interfaces for ISDN applications may require understanding how the interaction between users and communications services is affected by the representation of the application in the interface. In addition, they may call into question the role of human factors practitioners and researchers and the goals they should serve. Should we be content to design and evaluate interfaces to advanced services networks, or should we be using our knowledge of human needs and capabilities to drive the development of new applications to support.

Computer Systems: Approaches to User Interface Design

On Applying the Skills, Rules, Knowledge Framework to Interface Design BIBA 254-258
  Kim J. Vicente; Jens Rasmussen
In this paper, a theoretical framework for interface design for complex systems is proposed. The approach, called Ecological Interface Design (EID), is based on the skills, rules, knowledge framework of levels of cognitive control. The fundamental goal of EID is to develop interfaces that provide the appropriate support for all three levels, but that do not force cognitive control to a higher level than the demands of the task require. The framework, consisting of a set of prescriptive design principles, is discussed, and an example of its application is presented.
User Interface Consistency in the DECwindows Program BIBA 259-263
  Michael Good
A major goal of the DECwindows program is to provide a consistent, state-of-the-art user interface for workstation software. This interface extends across operating systems and many different types of application programs. Within the DECwindows program we have addressed both the technical and organizational aspects of developing consistent user interfaces across applications. Traditional methods for developing user interface consistency, such as the use of an interface style guide and toolkit, were supplemented with more innovative techniques. An exhibition and catalog of DECwindows application designs helped to develop a DECwindows school of interface design. Electronic conferencing software played an important role in facilitating communication among DECwindows contributors throughout the company. Preliminary user interviews suggest that the DECwindows interface style gives a consistent, usable feel to Digital's workstation applications.
Software Usability: Requirements by Evaluation BIBA 264-266
  Eric Smith; Antonio Siochi
Recent research has established the importance of defining usability requirements as part of the total requirements for a system. Instead of deciding in an ad hoc manner whether or not a human-computer interface is usable, measurable usability requirements are established at the outset. It is common to state such requirements in an operational manner: U% of a sample of the intended user population should accomplish T% of the benchmark tasks within M minutes and with no more than E errors. The formal experiments needed to test compliance with the requirements makes this method costly. This paper presents an alternative method of specifying usability requirements currently being developed and testing on a large software project at Virginia Tech.
   Briefly, usability requirements are specified by having every member of the software design team and the user interface design team specify the ease of use desired for each proposed functional requirement of the system under development. The individual ratings are then compared in order to arrive at a consensus. It is this consensus that leads to the formal usability requirements which the interface must meet or exceed. As the interface is built, it is rated in the same manner as that used originally to specify the requirements.
   This method thus provides a structured means of specifying measurable usability requirements and a means of determining whether or not the interface satisfies those requirements. Several other benefits of this method are presented as well.
Applying Human Factors Principles to Complex Software Systems BIBA 267-270
  Jim Fissel; Ron Crea
Over the past four years, the User Systems Engineering Group and the Industrial Systems Division of Texas Instruments have worked jointly on designing and developing a computer aided software engineering (CASE) tool to enhance the productivity of process and control engineers. This paper discusses the analysis and design procedures employed during this project and how these procedures focused on customer needs. Specifically, the areas addressed are the multidisciplinary design team, the task analysis, minimal-constraint analysis, and prototype design and iteration.

Computer Systems: Panel

Access to Electronic Office Equipment by Users with Disabilities BIBA 271-272
  Denise C. R. Benel
"...providing electronic equipment accessibility for individuals with disabilities who have special needs is an idea whose time has come" (GSA/ED Guidelines, 1987). The objective of the panel is to provide information to the Human Factors community on (1) the new GSA/ED Accessibility Guidelines with which all government procurements initiated after September 30, 1988 shall comply, and (2) selected issues related to accessibility of electronic equipment by those with disabilities.

Computer Systems: Interaction Styles

A Comparative Study of Gestural and Keyboard Interfaces BIBA 273-277
  Catherine G. Wolf
This paper presents results from two experiments which compared gestural and keyboard interfaces to a spreadsheet program. This is the first quantitative comparison of these two types of interfaces known to the author. The gestural interface employed gestures (hand-drawn marks such as carets or brackets) for commands, and handwriting as input techniques. In one configuration, the input/output hardware consisted of a transparent digitizing tablet mounted on top of an LCD which allowed the user to interact with the program by writing on the tablet with a stylus. The experiments found that participants were faster with the gestural interface. Specifically, subjects performed the operations in about 72% of the time taken with the keyboard. In addition, there was a preference for the gestural interface over the keyboard interface. These findings are explained in terms of the fewer number of movements required to carry out an operation with the gestural interface, the greater ease of remembering gestural commands, and the benefits of performing operations directly on objects of interest.
There's More to Direct Manipulation than Meets the Eye BIBA 278
  Robert W. Root; Annette Canby
The term "direct manipulation" (or DM) often evokes images of interfaces which are intuitive, obvious, and easy to learn. We conducted an experiment to determine whether subjects could learn to use a DM interface without instruction, i.e., whether they could learn the interface syntax on their own merely by inspection and exploration of the interface. The research vehicle was a prototype DM application designed to allow end users to customize a telecommunications application. Three variations of the interface were created by manipulating elements of the DM syntax, specifically, moded operations and rules about selecting objects before acting on them. Subjects carried out a set of five tasks in the presence of an experimenter, who was allowed to provide structured help when the subject could not make further progress. Results indicated that the syntax manipulations affected both the number and type of user errors and the amount of help needed to complete the tasks: the use of modes and selection rules significantly interfered with learning, and only four subjects out of thirty were able to perform the complete set of tasks without experimenter assistance. We also found, however, that more than half of the errors made by subjects were not directly related to syntax manipulations. These errors appear to stem more from conceptual problems, i.e., mismatches between the user's developing model of the interface and the model instantiated by the interface designer in the rules of interaction. These conceptual problems were observed across syntax manipulations and represent a significant portion of user's difficulties in learning the interface. Thus, our results shed light on the relationship between interface syntax, learning and usability in the DM paradigm, but they also point out the need for a cognitive account of the processes by which users acquire knowledge of interface characteristics and how that knowledge is related to interface design elements.
Empirical Evaluation of Entry and Selection Methods for Specifying Dates BIBA 279-283
  John D. Gould; Stephen J. Boies; Mia Meluson; Marwan Rasamny; Ann Marie Vosburgh
Experienced and inexperienced computer users used seven different interaction methods to specify dates of events. Key results were that the three entry methods were faster, more accurate, and preferred over the four selection methods -- by both experienced and inexperienced computer users. The rank order of performance with these methods was about the same for both groups. Number of keystrokes required by each method was a good predictor of performance time. For selection tasks, decomposing them into separate fields is advisable.
Entry-Based versus Selection-Based Interaction Methods BIBA 284-287
  Sharon L. Greene; John D. Gould; Stephen J. Boies; Antonia Meluson; Marwan Rasamny
Five different human-computer interaction techniques were studied to determine the relative advantages of entry-based and selection-based methods. Gould, Boies, Meluson, Rasamny, and Vosburgh (1988), found that entry techniques aided by either automatic or requested string completion, were superior to various selection-based techniques. This study examines unaided as well as aided entry techniques, and compares them to selection-based methods. Variations in spelling difficulty and database size were studied for their effect on user performance and preferences. The main results were that automatic string completion was the fastest method and selection techniques were better than unaided entry techniques, especially for hard-to-spell words. This was particularly true for computer-inexperienced participants. The database size had its main influence on performance with the selection techniques. In the selection and aided-entry methods there was a strong correlation between the observed keystroke times and the minimum number of keystrokes required by a task.

Computer Systems: Panel

Human Factor Assessment of Automatic Speech Recognition System Performance BIBA 288-290
  Tony J. Brown; Gary K. Poock; Arlene F. Aucella; Howard C. Nusbaum; Michael E. McCauley
Various methodologies have been proposed and implemented for the assessment of user performance with automatic speech recognition systems. Many human factors specialists are confronted with the problem of assessment and they need some answers. It is hoped that by concentrating on the human performance issue, with regard to speech recognition systems, some of the issues of assessment can eventually be resolved.

Computer Systems: Using On-Line Information

The Effects of Format in Computer-Based Procedure Displays BIBA 291-295
  David R. Desaulniers; Douglas J. Gillan; Marianne Rudisill
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-Test, 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 test 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.
The Effects of Hypertext on Reader Knowledge Representation BIBA 296-300
  Sallie Gordon; Jill Gustavel; Jana Moore; Jon Hankey
The goal of this research was to evaluate the effects of hypertext as an intra-document text format. Subjects read two articles on a color VDT, one in linear and one in hypertext format. Half of the subjects read general interest articles with instructions for casual reading and the other half read technical articles with instructions to learn the material. Afterward, subjects were given free recall tests, question probe tests, and a preference questionnaire. Results indicated that for both types of article, the linear format resulted in greater memory for the basic ideas contained in the articles. Also, for the general interest articles, subjects reading in linear format assimilated more of the macro-structure than subjects reading in the hypertext format. Consistent with these findings, a majority of the subjects expressed a preference for the linear format and perceived it as requiring less mental effort than reading hypertext. These results suggest that, at least under some circumstances, hypertext can interfere with normal cognitive processes.
Predicting Information Retrieval Performance BIBA 301-305
  Robert D. Peters; Gloria T. Yastrop; Deborah A. Boehm-Davis
This research examined the effects two different cognitive individual differences (perceptual speed and spatial scanning) on information retrieval performance under two matched and two mismatched database format/query conditions. A graphic and a tabular form of an airline database were constructed, along with questions that required users to search through the database to determine the correct response. Two types of questions were designed -- graphic and tabular. The data indicate that users are faster when the format of the information in the database matches the type of information needed to predictive of performance in the matched and mismatched conditions. Recommendations for database design are presented.

Computer Systems: Hypermedia and Interfaces: Design and Evaluation

Hypermedia and Interfaces: Design and Evaluation BIBA 306-307
  Bernice T. Glenn
Although hypertext and hypermedia have been discussed for a number of years, it is only recently that such systems have become generally available to interface designers. A user base of thousands exists at the present time, the most widely used system being HyperCard, from Apple. Hypermedia systems differ from traditional software systems in the complexity of its domains of access, its reliance on visual presentation, and in the use of sound. These differences are beginning to revise previously held ideas and guidelines about the processes of designing and evaluating software interfaces. This session presents some of the approaches to coming to grips with this problem... a problem that will continue to grow as technological advances continue in the development of readily available hypermedia software on inexpensive hardware platforms.
Interface Design for Hyperdata: Models, Maps and Cues BIBA 308-312
  Anne Nicol
Now that large stores of information in a variety of media can truly be at our fingertips, how do we know what we have and how to get at it? Hypermedia databases present new challenges to interface designers whose goals are to make such databases truly accessible and easy to use. In this paper, using HyperCard (1987) as an example, I discuss some of the user interface issues that arose as we observed children and adults interacting with computerized hypermedia environments. And I describe some design principles and examples that have emerged from our work in the Human Interface Group at Apple Computer, Inc.
Authoring Hypermedia for Computer Based Instruction BIBA 313-317
  Richard M. Lacy; Mark H. Chignell; Susan K. Kinnell
Recent recognition of the importance of writing and critical thinking skills, both within and beyond the scope of the university, has focused attention on the role of the research paper in the composition course. However attempts to teach the research paper, for the most part, have been unsuccessful. What is needed is a new model for the research paper which can be incorporated into the composition course. At USC we have developed such a model in the Project Jefferson interface. In this paper we discuss our experience in using the Project Jefferson model to author hypermedia based curricular tools and discuss issues in authoring hypermedia structures based on that experience. We report the results of structured interviews carried out with the personnel who were responsible for authoring the hypertext and index for Project Jefferson. We also interpret features of the authoring process in terms of their impact on the resulting compatibility between software structures and student cognitive structures, as observed in two related studies (Teshiba and Chignell, 1988; Valdez, Chignell, and Kinnel, 1988).
   The version of the Project Jefferson prototype interface used in this research is an adaptation of HyperCard to teach freshman students how to do research within the framework of a writing assignment. It is a self-contained research tool which assists in the development of skills to do research in the real world. Its overall conceptual metaphor is that of an electronic notebook with which students can gain access to a paper assignment on the US Constitution; read a dictionary or encyclopedia for background information on Constitutional issues, and download key ideas to their electronic notebook; search a database of bibliographic information, taking notes if need be, or simply downloading citations; and finally dumping all this information into a text file as the raw materials of a research paper. In this paper we discuss our experience in using the Project Jefferson model to author hypermedia based curricular tools and discuss general issues in authoring hypermedia structures based on that experience.
Browsing Models for Hypermedia Databases BIBA 318-322
  Felix Valdez; Mark Chignell; Bernice Glenn
Hypertext can be simply defined as the creation and representation of links between discrete pieces of data. When this data can be graphics, or sound, as well as text or numbers, the resulting structure is referred to as hypermedia. The strengths of hypermedia arise from its flexibility in storing and retrieving knowledge. Any piece of information, whether it be text, graphics, sound, numerical data, etc., can be linked to any other piece of information. In many ways, the problems of hypermedia stem from the very flexibility that is its chief advantage and justification. It is difficult to maintain a sense of where things are in a relatively unstructured network of information. While the associative nature of hypermedia increases the availability of large amounts of diverse information, this very diversity makes it easy for information and users to get lost. Hypermedia exacerbates the problem of getting "lost in information space" by providing a complex associative structure that can be traversed, but not fully visualized. Information gets lost because it becomes difficult to organize and tag effectively, while users get lost as they lose sense of where they are in the hypermedia.
   Getting lost or disoriented occurs when one doesn't know where one is. Solutions to the problem of disorientation in hypermedia appear to fall into two general classes. First, one can create maps or browsers that allows users to determine where they are in terms of the overall network, or regions thereof. Second, one can create tags, markers or milestones which represent familiar locations, much as a lighthouse signals location in the middle of a foggy night. This paper reports basic research on the identification of landmarks in a hypermedia application.
Development of a User Model Evaluation Technique for Hypermedia Based Interfaces BIBA 323-327
  Kenneth Teshiba; Mark Chignell
The model underlying the interface and its interpretation by the user is a key element of successful interface usage (Chignell and Hancock, 1986; Norman, 1986). Some of the critical characteristics of the system model that determine its effectiveness are: 1) the proximity between the user's model and the system model, 2) how well the system model is matched to its application, and 3) how easily the system model lends itself to navigation through the interface. Several interesting issues arise from studying these system model characteristics. One of these is how the system model can be built in order to meet the needs of all users. Ideally, a system model must be flexible to meet the requirements of users from varied knowledge bases and computing experience, yet must be specific enough to perform its function in an efficient manner.
   Evaluation of human computer interfaces has traditionally been limited to determining the effectiveness of linear text and graphics. Evaluation tools have generally been formulated as checklists which assess predominantly static characteristics of interfaces either through user (e.g. Chin, Diehl, and Norman, 1988) or expert evaluation (Hamel and Clark, 1986).
   The use of a hypermedia interface, with its many nested levels and pathways, may produce varied user models. Thus it is particularly important to evaluate a user's perceived system model versus the actual system model in order to determine the effectiveness and deficiencies of the interface when it involves a hypermedia application. Traditional evaluation techniques include user evaluation and feedback, analysis of user learning, analysis of user interface usage patterns. However, modifications to these traditional methods must be considered to meet the different challenges that a hypermedia interface presents. Methods of evaluation are needed for hypermedia, and for other applications where the human factors characteristics of the interface are not obvious from an assessment of its static characteristics.
   Through comparison of the user's perceived system model versus the actual system model it is possible to evaluate the effectiveness of a hypermedia interface in large part, and identify obvious deficiencies. The interface designer can then determine why idiosyncratic or inappropriate user models occurred and then alter the interface or user thinking (through training or online help) to improve the interface. This paper discusses two experiments carried out at the University of Southern California using the Jefferson prototype interface (a computer assisted assignment/online retrieval tool). These experiments use a novel method of evaluating the proximity between student models of the interface and the intended system model through the comparison of hierarchies built by students before and after using the software.

Computer Systems: Panel

Development of Documentation in Real Time BIBA 328-329
  Carol Bergfeld Mills; Elizabeth M. Comstock; Judith E. Dearlove; Janice C. Redish; Anna M. Wichansky; Joe Celline; John D. Gould
The primary purpose of this panel is to exchange information on common practices and procedures in the development of documentation for computer products (e.g. user manuals). This topic should be of great interest for anyone concerned with the development of usable computer products since documentation is a major part of the interface for most of these products. Yet documentation frequently receives very little or "last minute" attention from developers and producers. As a result, it is often confusing and difficult to use.
   The goal of this panel is to discuss problems encountered in developing documentation and what can be done to overcome some of those difficulties. The focus of the panel will be the problems of dealing with limited time and resources, as well as the relationships between different development groups (writers, hardware developers, software developers, and human factor specialists), and the decision-making process.

Computer Systems: User Interface Guidelines

Effects of Level of Abstraction and Presentation Media on Usability of User-System Interface Guidelines BIBA 330-334
  Ray A. Reaux; Robert C. Williges
User-system interface (USI) guidelines are emerging as a tool for user interface design. The roles of levels of abstraction (concrete and abstract) and of guideline presentation medium (hard copy or on-line) on detection of USI guidelines violations in user-system interface evaluation were investigated. Overall, less than 50% of the guideline violations were detected by software engineers. Abstract guideline violations were more difficult to detect than concrete guideline violations, and on-line presentation resulted in relatively higher guideline usage during evaluation than hard copy presentation. It was concluded that improvements in USI guideline form and media are required to make guidelines a more useful USI design tool.
Update of DoD-HDBK-761: 'Human Engineering Guidelines for Management Information Systems' BIBA 335-339
  Clifford Baker; David R. Eike; Thomas B. Malone; Larry Peterson
DoD-HDBK-761 "Human Engineering Guidelines for Management Information Systems" was extensively updated and revised to reflect 1) significant changes in computing technology, including user interface techniques and display technology, and 2) recent user computer interface (UCI) design literature. The document was updated based on literature reviews, mail-out surveys of UCI designers and users, and interactive computer interviews (using question and answer dialog). The updated document contains two main sections. The first presents a general process for conducting UCI analysis, design, development, and evaluation activities. These activities include; conduct of system functions analysis, function allocation, user task analysis, user surveys, use of UCI prototypes, and product testing. The second section contains over 1000 human engineering guideline statements which can be applied to the detailed design of UCIs. The guideline section addresses dialog design, computer control, data entry and display, job performance aiding, expert systems interface design, and data communication and protection. This paper discusses the content and organization of the document.

Computer Systems: Invited Address

Where Human Factors May be Headed: A Personal View BIBA 340
  Richard S. Hirsch
Following a brief review of how the human factors community achieved its present focus and circumstances, the discussion deals with what future preoccupations and opportunities may face human factors practitioners, such as computer software and documentation evaluations, the development of standards and guidelines, the avoidance of exposure to product liability cases, and the presentation of legislative testimony, among other concerns and challenges. Also examined are the roles that human factors funding and organizational structures may play in facilitating or inhibiting the effectiveness of human factors research and acceptance of the results obtained.

Computer Systems: Computer Menu and Screen Design

The Effects of Case and Spacing on Menu Option Search Time BIBA 341-343
  James R. Williams
The purpose of this study was to evaluate the effects of spacing and case (use of upper- or lowercase letters) on search time for menus presented on a contemporary high resolution PC display. Twenty Bellcore staff members, all experienced computer users, were presented two sets of four menus each (representing the combinations of case and spacing). Search time was recorded and participants were asked for their preferences among the four menu styles. Analysis of variance results indicated that double-spacing yielded significantly shorter search times in both menu sets. Although case was significant only for the first menu set, a significant case by spacing interaction for the second set indicated that double-spacing had more effect on search time for uppercase options than for lowercase options. Preference data also indicated that 85% of the participants preferred the double-spaced menus.
Consistent Layout of Function Keys and Screen Labels Speeds User Responses BIBA 344-346
  Jeanne P. Bayerl; David R. Millen; Steven H. Lewis
Personal-computer applications-software often requires people to navigate and select options using their keyboard's function keys where context-dependent meanings for these keys are assigned by guides or menus labeled on the screen. The physical layout of function keys on standard PC-compatible keyboards differs from the most common layouts of screen labels. This study examined user performance consequences of this simple, spatial, inconsistency. In a simulated order entry task, 36 participants each completed 240 trials, 40 with each of six different combinations of two keyboards and three screen guides with different spatial arrangements of function keys and screen labeling. One keyboard used the standard 5x2 function key pad and one used a single horizontal row of function keys; the screen guides were either a horizontal row, a vertical list, or a grid consistent with the standard key pad. We collected measures of response time, errors, and user preferences. Analysis of errors showed no reliable results. Analysis of response times showed several significant effects. Responses were faster with the two combinations of key pad and screen-guide layouts that were spatially consistent than with the four inconsistent layouts. Response times were also faster with the keyboard with horizontal function keys than with the standard layout, and slower with the vertical screen guide than with either of the other two guides. Over 80% of the participants thought the task was easiest when the screen guide matched the function key layout.
Deriving Menu Structures through Modal Block Clustering: A Promising Alternative to Hierarchical Techniques BIBA 347-351
  Mark S. Shurtleff; Joseph A. Jenkins; Michelle R. Sams
Modal block clustering (MBC) is proposed as an approach more suited to the derivation of menu structures than hierarchical clustering techniques. Problems with the application of hierarchical techniques and pairwise similarity ratings (PWSR) from which the clusters are derived are discussed. MBC defines clusters based on the pattern of common command attributes and provides an objective way to determine the composition and number of menu panels to include in a menu structure. The method also objectively defines command redundancy for the menu panels. The method of MBC was applied to the 97 commands that comprise the CMS operating system resulting in 17 menu categories. The menu categories were used to design a help menu system. The MBC procedure provides a viable methodology for complex systems, such as CMS, which derive increased functionality from numerous command options. System designers can fruitfully and efficiently apply this methodology both to current systems and to proposed systems for which there are no expert users.
The Impact of Task Characteristics on Display Format Effects BIBA 352-356
  David R. Schwartz
A study was conducted to determine how well the display format effects described by Tullis (1983, 1984) and the resulting prediction equations could be generalized to other display situations. Task complexity and visual monitoring load were identified as task variables which could potentially moderate the format effects and, thus, were varied factorially. The current study also sought to extend Tullis's findings to tasks where the use of several pieces of information from predictable display locations is required. In general, the data indicate the need to study Tullis's format dimensions more fully before using his regression equations to evaluate display designs for use outside the task situation in which the equations were developed. Also, subjects were unable to evaluate their performance accurately under alternative display designs. Their evaluations seemed to be determined mostly by the perceived ease with which information was extracted from the display. This outcome should serve as a warning to system designers. That is, empirical human performance research should be conducted when performance is the paramount design criterion and a validated prediction system, such as the one developed by Tullis for search, is not available.

Computer Systems: Prototyping

Interactive System Design with End Users using a PC Based Design Tool BIBA 357-361
  Christopher R. Koster; John H. Wilkinson
New PC based design and prototyping tools are making it easier to user interface designers to rapidly implement prototypes of new user interfaces for complex systems. We used such a tool to design the user interface for an on-line data base that was being developed to replace an existing batch system. The tool not only made the design of the user interface easier, but it also allowed us to present a prototype of the system to end users and to conduct design reviews in an interactive fashion. This allowed us to actively involve users in the design of the user interface and resulted in a better design that met both the users requirements and our own internal design goals.
Instant Prototyping Using HyperCard on the Macintosh BIBA 362-366
  Dwight P. Miller
Rapid interface prototyping (RIP) involves the simulation of potential user-interface designs for demonstrating and evaluating design concepts and iteratively modifying the interface designs without the burden of labor-intensive code generation and modification. In the past few years, many interface designers have had to use expensive equipment to help them perform RIP. Well, thanks to Bill Atkinson and the folks at Apple Computer Inc., you can purchase HyperCard software for your Macintosh for $49 and use it right out of the box for many of your RIP projects, without need of additional hardware (just add a cup of creativity). A special feature of HyperCard allows the designer to creat software-controlled buttons which, along with the graphics capabilities and the layering properties, permit the dynamic simulation of virtually any control panel that can be operated by discrete user inputs. Changes to the prototype can be made very rapidly (almost instantly) by an experienced HyperCard user, making it possible to modify an existing prototype "on-line" in a design meeting. This paper will describe this serendipitous application of HyperCard, its potential as an equipment-interface design tool, and describe how it was used to simulate the user interface for a weapons field tester, designed at Sandia.
Current Issues in Software Prototyping for Complex Systems BIBA 367-369
  Jim Fissel; Anthony Cecala
For many years the User Systems Engineering Group at Texas Instruments has been using software user-interface prototypes as a primary tool for the design and development of user interfaces for complex systems. Our model of the prototyping life cycle is introduced and its benefits are discussed. Current issues in prototyping often center around the introduction of new prototyping tools such as HyperCard or Prototyper. Our discussions focuses on how these tools fit within the prototyping life cycle.
Guidelines for the Use of a Prototype in User Interface Design BIBA 370-374
  Lovie A. Melkus; Robert J. Torres
Although the use of a prototype of the user interface of a software application early in the development cycle is a valuable tool in the design of a usable user interface, prototyping can be difficult to introduce into the development process. Furthermore, designers without experience in using a prototype can run into problems which counteract the value of this user interface design methodology. Designers with experience in a substantial prototyping effort have formulated guidelines for the use of prototyping which can help to minimize these problems.

Computer Systems: Panel

The Development of User-Computer Interfaces for Remote Access Data Bases BIBA 375-376
  Craig J. Petrun; Elizabeth Roop; Deborah A. Boehm-Davis; Philip J. Smith; Polly Brown
The recent surge in popularity of accessing on-line data bases from home terminals or PCs has drawn our attention to the limitations of today's remote access user interface technology. Although the type and complexity of on-line data bases continues to expand, there has not been an increase in emphasis on the development of a user-friendly interface to make remote data base accessing more usable. As a result, usage of these systems has gradually shifted to primarily professional information specialists and librarians.
   In order to open the access of these data bases to more non-technical users, we will need to integrate the various areas of human factors research which have already been involved in the design and implementation of on-line information systems. For example, research is currently being conducted in several areas related to on-line data base access, such as: 1) the impact of the data base format on retrieval, 2) consumer decision processes and information selection, 3) natural language interfaces, 4) the use of hypertext interfaces, and 5) on-line documentation aids.
   The focus of the present panel discussion is to provide a forum for integrating the results and ideas of several functionally related research areas in order to suggest future enhancements and design directions for future on-line data base access interfaces.

Computer Systems: Computer Users: From Beginner to Expert

Constraints on Training: Informativeness and Breadth in Procedural Skill Learning BIBA 377-380
  Scott P. Robertson; David Koizumi; Stacy C. Marsella
Three training methods were compared in a computer text editing situation. Training varied on the degree of constraint imposed on the behavior of learners. For complex methods, completely constrained and completely unconstrained training situations led to worse test performance than an unconstrained training condition in which subjects were informed about their compliance with a method and allowed to reset the system at will. The results argue against a strict "training wheels" approach to learning environments but support the general notion of "guided exploration," especially for complex methods.
Comparison of Typing and Handwriting in "Two-Finger Typists" BIBA 381-385
  C. Marlin "Lin" Brown
Twelve subjects who are not touch typists, but have a medium of ten years experience using computer keyboards performed two writing tasks: writing a short memorized passage and copying a four paragraph passage. Subjects performed each task once using a pen and paper and once using a display oriented text-editor. Typing speed was over five words per minute (wpm) faster than handwriting for both memorized and copied passages. Typing and writing were each about ten words per minute faster from memory than from copy. The number of errors was greater when typing from copy than in any other condition. These results suggest that for experienced two-finger typists, typing from a display-oriented document processor can be faster than handwriting.
On the Theory of Expert and Super-Expert Performance on Computer Program Modification Tasks: An Experimental Study BIBA 386-390
  Richard J. Koubek; Gavriel Salvendy
The present research attempts to identify factors which account for cognitive skill acquisition at the higher end of the cognitive performance curve and understand differences between expert and super-expert skill levels on a cognitive oriented task of computer program modification. Subjects completed two computer program modifications and a battery of five cognitive ability tests. Results indicate that super-experts used a global search strategy to obtain abstract information while experts utilized a minimal "directed" search to obtain task specific information. Results are discussed in relation to knowledge representation and current taxonomies of skill acquisitions.
Teaching User Interface Development to Software Engineers BIBA 391-394
  Gary Perlman
Most software engineers have weak backgrounds in areas where human factors engineers are strong: task analysis, applied psychology, and empirical evaluation. Software engineers can become better builders of user interfaces if they are instructed in these techniques, and that is the main goal of the Software Engineering Institute's graduate curriculum module on user interface development. Parts of the module provide instruction about when, where, and how consultants such as human factors engineers can contribute to the design and evaluation of user interfaces. It is critical that human factors engineers understand how they can contribute during development, so that they can have the greatest positive impact.

Computer Systems: Expert Systems

Knowledge Representation in Human Problem Solving: Implications for Expert System Design BIBA 395-398
  David C. Gibson; Gavriel Salvendy
The study focuses on the identification of the underlying representational properties of human problem solving and their application to expert systems. In this study the interaction between problem representation (procedural, conceptual, unstructured) and problem type (transformation, arrangement, inducing structure) was observed. The results of this study indicate partly that quantitative and qualitative differences in problem solving performance can be attributed to the form of knowledge representation employed by the problem solver. It is suggested that expert systems could be implemented with different shells or structures according to problem characteristics.
Optimization of User and System Knowledge BIBA 399-403
  Ann G. Hammer; Gerald G. Birdwell; Harry L. Snyder
This paper presents the perspective of a user system knowledge continuum which recasts traditional user system components (user interface, context-sensitive help, completion aids, manuals, training) as interrelated knowledge components tasked with appropriately distributing required knowledge between user and system. It suggests that maximizing user system effectiveness is best viewed as optimization of a set of such knowledge components. The paper relies upon a case study showing this perspective at work in the development of APT -- Applications Productivity Tool, an integrated software environment for industrial automation applications.
Design Practice and Application Domain: Primary Factors in Intelligent User-System Interface Design BIBA 404-408
  Roik L. Hockenberger; R. Jay Ritchie
Through the use of AI technology, the potential exists to make revolutionary changes in military command and control. Knowledge based systems can enable a commander and staff to accommodate large amounts of information efficiently and effectively, to generate operations plans rapidly, and thereby allow exploitation of early maneuver opportunities. This paper addresses the issues of applications domain and human factors design practice as they relate to the development of effective user system interfaces for expert systems.
Intent Inferencing by an Intelligent Operator's Associate: A Validation Study BIBA 409-413
  Patricia M. Jones
In the supervisory control of a complex, dynamic system, one potential form of aiding for the human operator is a computer-based operator's associate. The design philosophy of the operator's associate is that of "amplifying" rather than automating human skills. In particular, the associate possesses understanding and control properties. Understanding allows it to infer operator intentions and thus form the basis for context-dependent advice and reminders; control properties allow the human operator to dynamically delegate individual tasks or subfunctions to the associate. This paper focuses on the design implementation, and validation of the intent inferencing function. Two validation studies are described which empirically demonstrate the viability of the proposed approach to intent inferencing.

Computer Systems: Panel

Hypertext: A Human Interface Frontier BIBA 414-415
  James Bair; Greg Kearsley; Yoram Kochavy; Anne Nichol; Randall Trigg
This panel discusses the human interface considerations associated with hypertext. Panelists will present empirical, observational, or anecdotal data based upon their experiences with hypertext systems and users.

Consumer Products: Designing to Fit the Human

Design for All? The Use of Consumer Products by the Physically Disabled BIBA 416-419
  H. Kanis
Methodological aspects are considered of research into the use of consumer products by the physically disabled, especially into the operation of controls. The identification of impairments that provoke problems has revealed that only handicapped people with disabilities of both upper extremities are facing major problems in operating controls. The method applied is based on observation of users operating their own products at home. Subjects are people suffering from arthritis or a muscular dystrophy. Outcomes of the measurement of forces subjects can exert in turning, pinching and pushing, question the relevance of the measurement of the grip force with the widely used dynamometer as a valid indicator of the functional (im)possibilities of the hand. Finally it is shown that the procedure adopted, including the exertion of forces and the handling of controls by the subjects, does not have traceable effects on the performance of the subjects.
An Assessment of Industrial Designers Use of Human Factors Criteria in Product Design Evaluation BIBA 420-424
  Kamran Abedini
In order to know the pattern of actual application of human factors criteria by industrial designers an experiment was conducted by asking 87 students of industrial design to evaluate a CAD workstation after completing a course in "human factors in design". The guidelines chosen for the evaluation were those related to design of visual displays, controls and workstation layout on the CAD system. Since the main objective was to see how many of the principles had become part of their "common sense" they were asked to evaluate the equipment without any reference to any books/notes.
   The subject's responses were compared with the human factors guidelines using a Chi-square test (0.05 significance). The results pointed out that industrial designers readily accepted general criteria such as visibility, operability, and accessibility but interpretability of the display was frequently unrecognized. Such information could be used by industrial designers and human factors experts to improve their cooperation in the design process and thus increase the acceptance and marketability of the product.
The Design of a Squishy Mouse BIBA 425-429
  Peter R. Nolan
Five research studies were conducted to specify the physical description of a novel mouse for an office computer. The mouse had side buttons that when pressed at the same time, moved or scrolled the contents of the active window. The studies examined accidental activation of both the side buttons and the top buttons, whether the mouse should be single button or have multiple buttons on its top surface, the back width dimension, volume and silhouette, top button position, and side button size and position. Each study provided data that was used in the next study, after it was reviewed by a design team. This case study shows that in design/development environments, quick, iterative studies serve the needs of design teams by providing successive approximations to the final design in a timely fashion. The utility of this method is compared to a multifactorial design.

Consumer Products: The Design of Medical Products

When Electronic Devices Outnumber Flower Bouquets in the Hospital Room BIBA 430-434
  Michael E. Wiklund; Lawrence R. Hoffman
Today's hospital room is dominated by electronic devices that monitor, control, and document a patient's condition. The devices do what machines do best: tedious, repetitive tasks such as cardiac and respiratory monitoring requiring unerring accuracy. However, the proliferation of the devices, fueled by technological advances and the application of computers, is causing environmental and usability problems. Innumerable controls, displays, and alarms produce sensory overload. The devices congest the workspace, present tripping hazards, and produce unwanted noise, heat, and light. Using the equipment is not intuitive and requires substantial training. As a result, nurses and physicians spend more time working with the equipment and less time providing direct patient care. Reversing this trend requires better design and integration of equipment through the application of a usability engineering approach to product design and a commitment to design standards.
A Touch-Only User Interface for a Medical Monitor BIBA 435-439
  Steven J. Weisner
A touchscreen interface was tested as the exclusive means for interfacing with a computer-based monitor for the hospital intensive care environment. The use of touch in the medical environment combined with the fact that it was the sole means of user communication presented several human engineering challenges. Human factors testing of the design used 75 hours of mockup review by 38 clinical and administrative staff. In addition, 680 hours of field trial testing in the intensive care environment by 39 hospital staff were performed. The minimum size of visual and touch-sensitive target areas and the proximity of adjacent areas was determined. The touch recognition algorithm was modified to more accurately recognize near-edge targets. The use of a touch-sensitive QWERTY keyboard for patient name and id entry was shown to be acceptable. N-key rollover was deemed not viable with a touch interface in the critical care area. A swivel mount was introduced to compensate for different height and handed end-users.
Human Factors Considerations in the Design of Automated Systems for Nursing BIBA 440-444
  Carole Hudgings
This paper describes human factors relevant to the design of automated systems for clinical nursing information management, and several studies investigating human factors aspects of new clinical nursing information systems. Functions of systems to assist clinical nurses with information management are described. The importance of human factors in designing these computer systems is discussed by describing three categories of human factors: physical and demographic characteristics of nurses, characteristics of the hospital physical environment, and characteristics of the nursing care environment. Several human factors studies conducted by a multi-hospital corporation and two vendors to understand the nature and impact of human factors on systems design are discussed. Various data collection methodologies are described that investigate two different approaches to the design of hardware solutions for a clinical nursing information system.

Consumer Products: General Session

Consumers' Information Processing Objectives and Effects of Product Warnings BIBA 445-449
  Mark A. deTurck; Gerald M. Goldhaber
Based on human information processing theory it was hypothesized that consumers' information processing objective would influence the amount of time they devoted to examining product labels, their memory for product safety information, and as a result, the likelihood they would comply with safety recommendations. More specifically, it was expected that compared to consumers with an impression-set processing objective, consumers with a memory-set processing objective would: 1) devote more time to examining product labels; 2) recall more safety-related information; and 3) be more likely to comply with safety recommendations. Results provided unequivocal support for the first two hypotheses and only partial support for the third hypotheses.
Air Travel and Contact Lenses: A Laboratory Study BIBA 450-454
  Joseph E. Laviana; Frederick H., Jr. Rohles
The cabin of an inflight aircraft contains approximately 10% relative humidity (rh). To investigate the impact of this environment on eye comfort, an inflight humidity profile was simulated in a controlled laboratory setting. The experiment was replicated 3 times using a group of 4 subjects (2 males; 2 females) per test. Participants served in both control and experimental roles by wearing a hydrophilic contact lens on one eye and no lens on the other. Subjects provided evaluations of "eye comfort" for both eyes (contact and naked) at specified intervals during the 10-hour test. The results indicated that at 10% rh, there was no significant difference in eye comfort for either wearers or non-wearers of soft contact lenses. However, comfort decreased with the length of exposure (flight time), and for duration of six hours or longer a significant annoyance was reported.
Estimating Time Intervals Using a Recycling Camera Flash: User's Sensitivity to Flash Recycle Times BIBA 455-459
  David N. Aurelio
To determine user sensitivity to camera flash recycle times, 84 subjects evaluated a range of flash recycle times. Flash recycle time is the minimum time needed to re-power a camera battery between two camera flashes. The recycle time was increased from an "acceptable " recycle time to 30 seconds, or until the subject said he or she would replace the battery. It appeared that the rating and acceptability of a flash recycle time was related to the user's current flash recycle time. Subjects typically estimated that their own camera flash recycled in 2-5 seconds even though the actual range of times for the subjects' cameras was 0.5 to 10 seconds. A similar discrepancy occurred when the subjects were asked when they would replace their camera batteries. Possible explanations for estimation discrepancies and reasons for battery replacement are explored.

Educators' Professional: Contemporary Issues in Human Factors Education

Visual Assessment vs. Statistical Goodness of Fit Tests for Identifying Parent Population BIBA 460-464
  Mari Berry; Brian Peacock; Bobbie Foote; Lawrence Leemis
Statistical tests are used to identify the parent distribution corresponding to a data set. A human observer looking at a histogram can also identify a probability distribution that models the parent distribution. The accuracy of a human observer was compared to the chi-square test for discrete data and the Kolmogorov-Smirnov and chi-square tests for continuous data. The human observer proved more accurate in identifying continuous distributions and the chi-square test proved to be superior in identifying discrete distributions. The effect of sample size and number of intervals in the histogram was included in the experimental design.
Ergonomics Awareness Training for Industry BIBA 465-467
  John K. Schmidt; Barbara Weidman; John Katchan
Many manufacturing firms across the United States are introducing basic ergonomic principles into their production lines. The rationale for this stems from two basic sources: 1) promote higher quality workmanship through reduced worker fatigue and 2) increase occupational health and safety through improved job design. Several firms have opted to include ergonomics awareness training for their employees as part of this effort. The inherent challenge of this undertaking is to design a course of instruction which can effectively disseminate enough background material to achieve ergonomics awareness. The intention of this paper is to discuss the process which was used in developing conducting, and evaluating such a course of instruction.
Instructional Use of Personal Computers in Human Factors Labs BIBA 468-472
  Andris Freivalds; Joseph H. Goldberg
With the ubiquitousness of personal computers (PCs), it is only natural that they should be utilized in human factors laboratories not only for research data collection but also as an educational tool. With large engineering classes, most labs cannot afford to have multiple meters and instruments to service several identical laboratory stations simultaneously. Instead, it is extremely helpful to have several PCs with programs depicting basic human factors principles running simultaneously with the other stations. Thus, the PC programs are not intended to eliminate hands-on experimentation, but to help alleviate loading problems and provide useful educational principles.
Course Critiques; What Students Can Tell Us about Educational Efficacy BIBA 473-477
  David B. Porter
A course critique based on a multi-channel model of education has been developed and administered to all students enrolled in behavioral science courses at the US Air Force Academy for the past three semesters. The utility of this approach is shown by data analyses at three levels: department, course and instructor. Several pedagogical implications are discussed.

Educators' Professional: Professional Aspects of Student-Directed Research: Four Perspectives

Professional Aspects of Student-Directed Research: Four Perspectives BIBA 478
  R. Craig Montero; Paul Green
This symposium deals with the special opportunities and difficulties presented to students who serve as principal investigators or project managers.
   Issues such as funding, time allocation, resource availability and laboratory space will be addressed. The novel and sometimes exciting methods devised to cope with shortfalls (especially funding) and unexpected problems will be presented. The special opportunities that student directed research creates in terms of directing other students (both graduate and undergraduate) will also be discussed. Both graduate and undergraduate perspectives from several universities and different types of human factors programs have been brought together to discuss this important professional objective. A period for open discussion among participants and attendees is included.
Student Initiated Research: One Student's Perspective from Rice University BIBA 479-481
  David R. Desaulniers
This article describes issues which are particularly relevant to students attempting to initiate an independent research program. The assumption is made that students will have to implement their research with very limited funding. Several techniques for minimizing costs and procuring necessary resources are presented. Alternative methods of research are discussed as well as problems associated with obtaining the professional guidance often necessary for such ventures.
Student Research: A Perspective from Old Dominion University BIBA 482-484
  Paula J. Guerette
The process of completing a major research effort such as a thesis or dissertation requires the consideration and successful coordination of many details. The present paper addresses the way in which two major factors -- selection/design of a research project and acquisition of funding -- were resolved in the present research effort.
Student-Initiated Human Factors Research at Michigan: A Guide for Research on a Shoestring BIBA 485-489
  James R. Sayer; Paul Green
This paper describes how and why an undergraduate student might go about conducting an independent research project, citing a study conducted by the authors as an example. Specifically, this paper discusses the benefits of such an effort, how to find an advisor, what might be expected of a student, and how long it might take. For each of these issues, likely problems are discussed as well as possible solutions. Based upon their experience, the authors believe that the critical factors are the perseverance of the student and advisor, and the quality of the project planning.
Undergraduate Research: A Pedagogical Experiment BIBA 490-494
  Troy J. Ziegler; David M. Koch
Students cooperatively conducted research experiments in an upper division cognitive psychology course in the Behavioral Sciences and Leadership Department at the United States Air Force Academy. The pedagogical structure of the course was modified to emphasize teaching cadets how to think versus what to think through the process of conducting research. Students were expected to cooperate in pairs to design and conduct their research. Cooperative research projects were used in the attempt to develop critical thinking skills and intrinsic motivation to excel. This paper presents the authors' views on the rationale and perceived benefits of cooperative research projects in upper division courses to develop critical thinking skills and intrinsic motivation.

Educators' Professional: Panel

Undergraduate and Graduate Courses in Industrial Ergonomics, Industrial Human Factors and Industrial Safety -- Where are We Today and Where Do We Need to Be in the Future? BIBA 495
  Helmut T. Zwahlen; Fereydoun Aghazadeh; Colin Drury; Daryle Jean Gardner-Bonneau; Steven Johnson; Stephan Konz; Anil Mital; Mark Sanders
The field of human factors, ergonomics, and safety has grown and expanded rapidly over the last two decades. The area of industrial ergonomics, industrial human factors, and industrial safety is becoming a smaller and smaller subset among the new emerging areas within the general human factors field and efforts of the Human Factors Society. The Human Factors Society has started an accreditation program for human factors education at the graduate level. At this point in time the accreditation document of the Human Factors Society is rather non-specific when it comes to the descriptions, teaching strategies, and experiences of industrial ergonomics, industrial human factors, and industrial safety courses.

Environmental Design: Management and Design of Work Environments

Naturalistic Observation of Adjustable VDT Stand Usage BIBA 496-500
  Paul Cornell; Doug Kokot
Ergonomists have long recommended user adjustable furniture for office workers. A majority of the recommendations have been based upon anthropometric models of ergonomically "correct" postures. Research validation of these proposals is sparse, and those that have been conducted are predominantly laboratory oriented. This research observed the use of adjustable furniture in a field setting. Three questions were addressed: 1) what are the preferred settings when the equipment has been used for a length of time?; 2) do people change the settings?; and 3) how do these measures relate to anthropometric data? The offices of 91 workers were measured covertly. Twenty-one offices were measured once, 41 twice, and 29 three times. All the offices had an adjustable VDT stand with independent height and angle adjustments for both the keyboard and display. Seat height had a mean and standard deviation of 20.0 and 0.85 inches. The height of the home row of the keyboard had a mean of 29.1 and a standard deviation of 1.2 inches. For the display surface the mean and standard deviation were 29.7 and 1.3 inches. In terms of repeated measures, 62.9% of the chair heights, 57.1% of the keyboard heights, and 91.4% of the display heights did not change. Of the observed changes, 90% were between 0.25 in and 0.75 inches. None of the observed heights correlated well with stature, seated eye height, or popliteal length. One correlation was 0.32, all others were less than 0.20. The results are similar to other published data in that the measured settings are much higher than anthropometric models would predict. More significantly, they do not match the new ANSI guideline nor the proposed CSA guideline for adjustable furniture. This suggests that the ergonomic theories behind these recommendations need to be modified to more closely reflect actual use products.
"Recommended" versus "Preferred" in Design and Use of Computer Workstations BIBA 501-505
  Boris Povlotksy; Vitaly Dubrovsky
Due to the recent development of adjustable office furniture and elements of computer hardware, a new "preferred settings" approach to VDT workstation (VDTW) design has emerged in opposition to the traditional recommended standards. This approach studies the "recommended-preferred" controversy on the population level in terms of means, ranges, and percentiles and sets new dimensions and ranges of adjustment for the design of the VDTW components. While the VDTW's components are designed in a view of population, they are used by individuals. This paper raises the issue of studying the "recommended-preferred" controversy on the individual level in relation to the task of customizing VDTW's for individual users. Preferred individual adjustments of the experimental VDTW made by 23 subjects were compared to the respective, recommended individual adjustments. Although all recommended-preferred differences were statistically significant, almost all preferred values were either very close to the corresponding recommended values or deviated from the recommended optima without exceeding the recommended ranges. The paper discusses implications of this result for the customizing of the VDTM's for individual users.
Effects of Social Interaction on Performance and Mood State During Computer-Based Data Entry Work BIBA 506-510
  Robert A. Henning; Edward F., Jr. Krieg; Steven L. Sauter
The effects of social interaction on performance and mood state were investigated for computer-based data entry work. A highly repetitive, screen-based, numeric data entry task was performed in a laboratory environment. Experienced data entry workers (N=16) performed the task under social and nonsocial conditions. Pairs of subjects worked at a room divider prevented visual contact and conversation was not permitted. During the nonsocial condition a room divider prevented visual contact and conversation was not permitted. During the social condition visual contact and conversation were permitted. Each condition consisted of three, 40-min work periods separated by 10-min rest breaks away from the workstation. The two subjects entered lines of data which had the same or an unequal number of characters so that interactions between task similarity and social/nonsocial conditions could be evaluated. Keystroke output, error rate, and the number of character corrections with the backspace key were scored for each work period. In addition, a survey of mood state was administered before and after each work period. Data analyses indicated that tension, irritation, perceived stress and error rate were less in the social condition. No effect on total keystroke output or backspace use was found in the social condition. No interaction between task similarity conditions and social/nonsocial conditions was found. These results suggest that social interaction during data entry work can benefit worker well-being and error rate performance without significantly affecting keystroke output. These results have implications for the design of work environments for data entry workers.

Environmental Design: Evaluating the Impact of Design

Relative Contribution of Behavior to Slip and Fall Accidents in Mining Maintenance BIBA 511-514
  Thomas J. Albin
Bureau of Mines research has indicated that slip and fall accidents are a major cause of injuries during the maintenance of surface mining equipment. All such injuries during 1985, 1986, and the first half of 1987 were studies for information as to accident causes, particularly whether the nature of the causes were worker behavior or machine design. Accidents judged to be solely caused by behavior of the injured individual constituted only 11 pct of a total of 1384 accidents. An interaction of machine design and behavior was found to be involved in 31 pct of the accidents. The information presented in this study as to antecedent events to slip and fall accidents may be useful in designing intervention strategies to decrease slip and fall injuries.
Help for the Handicapped, or Hindrance? BIBA 515-518
  John K. Schmidt; Salvatore P. Schipani; Kragg P. Kysor
During the Seventies, legislation was enacted to open areas to the physically handicapped. Subsequently, newer structures began to accommodate the physically disabled, whereas older structures were systematically modified to increase accessibility. The intent of the present effort was to examine a train station overpass intended to provide access to the handicapped and determine if the requirements it imposes on its users were feasible. The analysis indicated that the current design places excessive demands on users, and should be modified. The paper suggests some possible modifications for the present structure.
A Model for Describing Performance and Productivity BIBA 519-521
  Frederick H., Jr. Rohles
A model for describing performance and productivity is presented as an equation in which Performance (P) is equal to the product of basic skills or ability (A) and motivation or drive (D), plus an oscillatory communication, training, and environment. Emphasis is placed on the multiplicative function of ability and drive and explains how highly motivated persons of average ability can exhibit better performance than individuals with the same ability who are poorly motivated. Implications for the human factor community, as it relates to the oscillatory factors, are discussed.
Standing Work: Carpet vs. Concrete BIBA 522-526
  Malgorzata Rys; Stephan Konz
A significant part of the workforce works with the feet and legs in a relatively static standing position.
   In an experiment, 20 college students (mean age = 23) stood wearing 2 pairs of socks but no shoes at a table for 240 minutes (120 minutes on carpet on one day and 120 minutes on concrete on another day). Ten subjects stood in the morning and 10 in the afternoon. Foot volume and instep vertical and horizontal circumference and calf circumference did not differ significantly between morning and afternoon or between carpet and concrete. Heart rate did not differ between morning and afternoon but the 95.2 for carpet was significantly lower than the 100.1 for concrete. Perceived comfort ratings were higher for carpet than concrete. Body areas in which comfort decreased the most while on concrete were: lower leg, upper leg, ankle, whole foot, the neck and the shoulder. When the individual factors were combined into a single factor using factor analysis, the 77.7 score (0-100 scale) for carpet was significantly better than the 71.9 concrete.

Forensics Professional: Forensic Forum: Research for Litigation

Fault Logic Analysis of Product Safety BIBA 527-531
  David A. Thompson
The purpose of this presentation is to trace the development of Fault Logic Trees, explain their theoretical structure, discuss their forensic importance, and present four illustrative examples of their use in past court cases. The examples are all man-machine interactions, and include a variety of formats and one probabilistic risk tree.
Cuing Hazard Information for Consumer Products BIBA 532-535
  Kimberly A. Donner; John W. Brelsford
Rice University undergraduates were given cued and non-cued consumer product questionnaires in order to determine the degree to which product cues would elicit user hazard knowledge, as measured by the number of generated accident scenarios. The difference in the number of scenarios generated by the two groups was not found to be statistically significant. However, there did exist a relatively strong, and significant, relationship between the number of generated accident scenarios and reported hazardousness, degree of precaution that would be taken, and the likelihood of reading the warnings associated with the product. The relationship between the production of known accident information in the form of accident scenarios and these dimensions is thought to have implications for the content of product warnings.
A Behavioral Study of Warning Labels for Consumer Products: Perceived Danger and Use of Pictographs BIBA 536-540
  Shirley M. Otsubo
This study focused on the effectiveness of warning labels placed on consumer products differing in perceived "danger" or "hazard". A 2x4 between-subject design (N=131) was performed, incorporating two levels of product danger (circular saw=high level of danger; jigsaw=low level of danger) and four levels of warning label (words only, pictograph only, words+pictograph, and no warning). Effectiveness was investigated by studying the behavior of product uses to determine who noticed, read, complied and recalled the warning message. Overall results indicated that subjects noticed, read and complied with warnings placed on the product perceived to be more dangerous than on the product perceived to be less dangerous. Additional data suggest that people more familiar with use of the product will tend to read, comply and recall the warning less than those less familiar. Also people more confident with the use of the product will tend to read and comply less than those less confident. Type of warning label showed no effect. However, in all conditions with a warning label, an average of 25.5% complied with the warning (range 12.5-50%), and without a warning label no one took precautionary action consistent with the warning message. The findings support the contention that the use of conspicuously designed and placed warning labels on products will influence people to behave cautiously.
Bias in Photospreads of Faces: A Comparison of Two Lineup Construction Methods BIBA 541-543
  D. Bradley Marwitz; Michael S. Wogalter
Recent research suggests that the current method of lineup construction produces biased or suggestive lineups. Earlier studies used face composite stimuli to assemble the lineups. The present study uses more realistic materials, actual face photographs. Ten pairs of subjects constructed photospread lineups using the traditional method of selecting lineup members who are similar in appearance to the suspect. Another ten pairs of subjects constructed lineups using an alternative construction method. The lineups were then given to a separate group of subjects who had never seen the photographs before and were asked to try to select the face that was the basis for each lineup. The results showed that traditional lineup construction method produced bias towards the target/suspect. The alternative construction method produced less bias, but not significantly less than the traditional method. These results have implications for law enforcement personnel concerned with the construction and presentation of lineups.

Forensics Professional: Panel

Extracting Testimony from the Human Factors Expert Witness BIBA 544
  Lorna Middendorf; Robert J. Cunitz; Foy R. Devine; K. Norman Kripke; Joseph Epstein; Scott Lawrence
The purpose of this panel is to focus on concepts and procedures used by the human factors expert witness in providing evaluative and court-related services in product liability and similar legal actions. The role of the human factors expert witness during trial and specifically during the taking of trial testimony will be presented with analysis and discussion to demonstrate direct examination of qualifications or voir dire, presentation of scientific foundations, opinions and conclusions.
   This panel has been planned as part of an annual meeting series to answer expressed member needs for information on legal procedures, the experience and techniques of other experts, training on tactics and strategy for participation in the adversarial legal system, and ethics/standards regarding giving testimony (Forensics Professional Technical Group Survey, 1987). There will be a legal/human factors approach with a witness-attorney demonstration of direct testimony to promote an understanding of the special role of the human factors expert witness in providing competent, ethical and understandable testimony to assist the trier of fact in litigation. An important goal is to provide participants in the panel session with some basic knowledge for appropriate conduct during the process of trial direct examination.

Forensics Professional: Human factors Forensic Issues in Slip, Trip, and Fall Litigation

Factors Influencing the Measurement of Slipperiness BIBA 545-548
  Mark S. Redfern
The evaluation and prevention of slips and falls require methods of quantifying the slipperiness of floors. The concept of coefficient of friction (COF) has been and continues to be commonly used as one such method. The objective of this paper is to present some results from investigations into the effects of vertical force and velocity on COF measures for different types of floors. Tests involving both static COF (SCOF) and dynamic COF (DCOF) measurements were performed under various conditions. It was found that the SCOF changed as a function of the vertical force used. Generally, the SCOF increased as the vertical force was increased. This was not true, however, for tile floors. It was also found that there was a significant first order interaction effect on the SCOF between vertical weight and the condition of the floor (wet or dry). The dynamic tests showed that velocity of the shoe material with respect to the floor had a large effect on the DCOF values obtained. The velocity effect was dependent on the shoe material and the conditions tested. Possible reasons for these findings and ramifications on slip testing are presented.

General Sessions: Potpourri

Considerations of Intention and Movement: Action Plans and Motor Programs in Speech and Keyboard Entry BIBA 549-553
  Patricia A. Mullins
The cognitive organization and control of rapid movement sequences was investigated in speech and keyboard entry. Five reaction time experiments were carried out with various manipulations of stimulus meaning. A linear increase in reaction time with an increase in the number of items to be produced was evident for spoken lists of random digits, single words in random order, and repeated syllables but not for single words arranged into meaningful context. A speech interference condition produced a linear increase in reaction time in a key pressing task when it was necessary for the action to be planned ahead of time. These results indicate that meaningfulness of stimuli facilitates movement organization, an effect which can have significant impact on input technology.
The Relative Pleasantness and Distinctiveness of a Variety of Auditory Patterns BIBA 554-557
  Linda A. Roberts; Joel Angiolillo-Bent
There are numerous instances in which auditory patterns could be employed to give a variety of signals or messages. The aim of this research was to investigate those sound qualities which contribute to an auditory signal's pleasantness and distinctiveness. A variety of auditory schemes were assessed, based on a number of different musical and acoustic dimensions. It was observed that patterns that varied along the rhythmic domain were most easily distinguished while frequency modulated intervals were judged to be most pleasant. The scheme that optimized both distinctiveness and pleasantness entailed four-note melodic sequences.
A Comparison of Equations and Methods for Determining Percentage Body Fat BIBA 558-562
  Jeffrey E. Fernandez; Kenneth H. Pitetti; Nancy B. Stubbs; Robert J. Marley; Mihriban Cihangirli
An experiment was conducted to assess the differences between various equations and devices for estimating body fat percentage. Valid estimation of body fat is an important variable in determining the individual differences in energy expenditure or physical work capacities of workers performing various tasks. Twenty male volunteers participated in this study. Results indicate that no significant differences exist between device type. However, there were significant differences between derived estimations of body fat content with several widely used equations. These results were also related to estimation of body fat content derived from the bioelectrical impedance procedure. Results from this study indicate the need for comparison between subject population and population of prediction models before determining body fat and possible use of an average of several equations.
Ambient Heat and Nerve Agent Antidotes: Effects on Soldier Performance with the USARIEM Performance Inventory BIBA 563-567
  Richard F. Johnson; John L. Kobrick
The tactical significance of chemical weapons in future warfare demands that nerve agent antidotes be available for troops exposed to chemical attack. Since future combat operations will likely occur in desert and tropical areas, chemical attacks in such areas could lead to situations involving the use of nerve agent antidotes by troops during exposure to hot weather conditions. This study assessed, both independently and in combination, the effects of heat exposure (95-degrees F, 60%RH) and US Army standard dosages of nerve agent antidotes (2 mg atropine and 600 mg 2-PAM chloride) on the performance of a variety of tasks selected from the USARIEM Performance Inventory (UPI). The UPI tasks selected for inclusion assessed sensory functioning, perceptual-cognitive functioning, sensorimotor skill, subjective reactions, and M16 rifle marksmanship. Fifteen soldier volunteers were first trained to asymptotic performance on the UPI task battery. Then, over a period of four test days, they completed a counterbalanced schedule of the drug/no drug and heat/no heat conditions while outfitted in the Battle Dress Uniform. On each test day, the tests from the UPI were administered once during each of the three 2-hour test cycles. Compared to the placebo condition, a single dose of nerve agent antidote significantly impaired soldier performance such that visual reaction time was 5 to 11% slower, gross body mobility was 12% poorer, rifle marksmanship (pop-up targets) was 3% less accurate, and verbal reasoning was 6% slower. Compared to the 70-degree F condition, the 95-degree F ambient condition significantly impaired soldier performance such that arm-hand steadiness was 10% poorer, manual dexterity was 2% poorer, and rifle marksmanship (tightness of shot group) was 13% less accurate. Nerve agent antidote and ambient heat did not interact to further impair soldier performance.

General Sessions: Driver Performance On the Highway of the Future

Legibility and Comprehension of Traffic Sign Symbols BIBA 568-572
  Jeffrey F. Paniati
In recent years, symbols have been used to improve the ability of traffic signs to communicate their messages. A study of traffic sign symbols was recently completed at the Federal Highway Administration Turner-Fairbanks Highway Research Center in McLean, Virginia. In this study, a laboratory experiment was conducted to determine the relative legibility distance and driver comprehension for 22 symbol warning signs currently in use in the United States. The results showed that the legibility distance of symbols decreases with increasing driver age and that bold symbols of simple design provide the best legibility distance for all age groups. This study also showed that the legibility distance for symbolic signs can be equal to that of alphabetic signs or have as much as 4 times greater legibility distance depending on the message. The sign comprehension data indicated several symbols need redesign or increased driver education efforts.
Modeling Driver/Vehicle Performance in Emergency Maneuvers BIBA 573-577
  R. Wade Allen; Henry T. Szostak; Theodore J. Rosenthal
The combined performance of the driver and vehicle determine whether accidents result from traffic conflicts, road hazards, etc. This paper describes the driver behavior and hazard scenario aspects of a computer simulation which models both vehicle dynamics and driver steering and braking behavior. The technical aspects of the simulation have previously been published. The issue of how much the driver and vehicle contribute to accident involvement is addressed, and antilock brake evaluation is used as an example.

General Sessions: Human Factors Inside the Automobile

Comparing Ease-of-Use of Steering Wheel-Mounted and Conventional Radio Controls BIBA 578-582
  Eugene Farber; Susan Salata
A study was conducted to compare driver performance with a limited set of steering wheel-mounted and conventional panel-mounted radio controls. The study was conducted with subjects driving under actual freeway traffic conditions. Drivers took less time to locate and use the wheel-mounted controls, had less eyes-off-the-road time and made fewer errors with them than with the conventional controls.
The Older Driver -- A Challenge to the Design of Automotive Electronic Displays BIBA 583-587
  T. H. Rockwell; Arol Augsburger; Stanley W. Smith; Scott Freeman
Older drivers present unique challenges to the display designer. Approximately 30 percent of all drivers in the U.S. are over 50 years of age. Visual impairment, e.g., presbyopia, begins after 40. After age 55, approximately 91 percent of the population use bifocals. Unfortunately, bifocals with significant add power create zones of decreased acuity in the critical instrument panel viewing distances of 500-800 mm.
   In this paper, the demands for vision in driving are related to the special visual disabilities associated with the older driver, such as increased sensitivity to glare, high contrast ratio blurring of electronic displays and increased time for target recognition. A computer legibility model is presented to relate the principal factors in design, namely character height and width, viewing distance, contrast ratio and background luminance with legibility impairment associated with various age groups. Implications of model predictions to display design are discussed.
Car Seat System of the Future as Seen in "ARC-X" BIBA 588-592
  Toshimichi Hanai; Hideyuki Nagashima
Car seats of the future will have to give even greater consideration to the human aspects of comfort and style. Moreover, driver and passenger seats need to be designed separately, to optimize each seat according to its function and location the car interior. The seat system of the "ARC-X" experimental car is based on the results of body pressure distribution measurement, subjective evaluation, and other human engineering techniques. These were used to analyze driver and passenger postures from the standpoints of performance and comfort. This paper introduces features of the driver's seat and front and rear passenger seats adopted in the "ARC-X", and reports some of the analytical results on which their design was based.
An Examination of Body Support and Fatigue in Automobile Seats BIBA 593-597
  Kuniyoshi Date
There are various factors that influence the sitting comfort of automobile seats. Important elements that often determine how a seat is assessed in terms of sitting comfort are the fatigue phenomena that occur on long drives. This work examined the possibility of reducing fatigue by providing an optimum fit between the seat and the occupant's body and optimum sitting posture. This report presents the results of evaluations and analyses made of fatigue and the feeling of fit for many different types of seats, including a bucket seat.

General Sessions: Panel

Selling Ease of Use: Human Factors Partnerships with Marketing BIBA 598-602
  Anna M. Wichansky; Charles N. Abernethy; Miriam E. Kotsonis; D. C. Antonelli; Peter P. Mitchell
As customer demand surges for products which are easy to use, human factors and marketing professionals are working together more frequently. The purpose of this panel is to discuss ways in which human factors and marketing can interact to provide and promote usability. Panelists will share their successes and failures in working with marketing by describing case studies of collaborative work. The pros and cons of joint efforts will be discussed in a moderated question and answer format with audience participation. Brad Woolsey of Parallax Marketing Research will be a discussant.

General Sessions: Shiftwork: Effects on Safety and Productivity

Shiftwork and Industrial Injuries at a Chemical Plant in South-East Texas BIBA 603-607
  R. D. Novak; M. H. Smolensky
A historical retrospective study of 242 shiftworker (SW) and 224 non-shiftworker (NSW) injuries at a chemical manufacturing plant in southeast Texas was performed. The shiftworker schedule comprised an 8-hour, 7-day backward rotation program, while the NSW schedule consisted of a normal 40-hour work week. Injury records were matched against payroll/attendance records to enhance the probability of isolating possible effects of the shiftwork rotation schedule on the rates, distribution and severity of injuries. For SW injuries, analysis by chi-square comparing day worked into shift with shift rota indicated that the occurrence of an injury, the day worked into each shift and the rota were associated. For the period studied, SW's had more confirmed injuries during the first 4 days of day and night shift than during the evening shift. Female SWs had a significantly higher reported injury incidence rate than did male SWs while maintaining a similar distribution of injury severity ratings. Among NSWs, injury incidence rates were not significantly different between males and females. The number of injuries were not found to vary significantly by clock hour during each shift but did decrease on the average as the shift worked occurred later in the day. It was believed that the rotation direction and reduced number of hours off during evening-day and day-night shift changes may have contributed to the differences in the distribution of injuries for shiftworkers.
Time-of-Day Variations in the Severity of Injuries Suffered by Mine Shiftworkers BIBA 608-611
  Jon A. Wagner
One means of assessing the hazard risk associated with mine work is to study the severity of injuries that occur during the course of the workday. Of special interest is the accident risk inherent in night work and rotating shiftwork. To better understand this risk, the Bureau of Mines conducted a study of accidents that occurred during a 10-year period in the taconite (iron) mining operations of the U.S. Lake Superior iron ore region. In general, accidents that occurred during the night shift resulted in more days lost per accident, compared with either the day or afternoon shifts. To control for the possibility of different accident types occurring on different shifts, part of this study focused on accidents involving equipment operation. Again, night shift accidents were shown to be significantly more severe than on the other two shifts. These results implicate work performance during night hours as being relatively impaired, perhaps due to lowered states of psychophysiological arousal, coupled with the handicap of operating in a darkened environment.

Industrial Ergonomics: What Shall We Do and How Will We Do It? Job and Task Design

The EDGE System: Ergonomic Design Using Graphic Evaluation BIBA 612-616
  Susan M. Evans; Susan L. Palmiter; Jay Elkerton
EDGE is a computer-based ergonomic workspace design system which integrates several models of operator performance with a common graphic interface. In addition to serving as a practical design system, it also serves as a research tool for understanding the ergonomic design process in industry. System users include trained ergonomists and engineers responsible for manual workspace design. The design system centers around a core vocabulary of task-related terms. A common input format, modeled after the traditional "work methods table" addresses the input requirements of the varied human performance models. Output from the performance models is displayed on multiple screens in varying levels of detail. Among the measures of physical stress currently integrated into the system are models of biomechanical strength, NIOSH lifting limits, metabolic energy expenditure, and elemental time prediction.
Development of an Expert Systems for Ergonomic Workplace Design and Evaluation BIBA 617-621
  Eui S. Jung
Industrial workplace design and evaluation is the outcome of a multi-factored process which requires diverse disciplines and interrelated techniques to consider alternative factors and to achieve an optimal design solution. However, it is still evident that industrial workplace design fails to incorporate ergonomic principles throughout all stages of design and evaluation. One approach to solve the problem is to introduce an expert system for integrating existing analytic models and expertises into a framework which guides the designer along the necessary steps to reach a solution, with explanations on its reasoning process. This paper discusses the framework of the prototype expert system being implemented using VM/PROLOG on IBM VM/CMS mainframe. The rule-based production system was selected as a representation scheme due to its versatility and expressive power. It is consisted of two main parts. First, modularized knowledge bases incorporate multidisciplinary ergonomic factors such as biomechanics, work physiology, and psychophysics. Each module stores knowledge either in the fact base or the rule base, however, massive experimental findings and table-lookups are separately stored in the external database through its interface and retrieved without bothering the main inference mechanism. Secondly, inference mechanism was built as a control mechanism, with a front-end user interface. It has a pattern-directed architecture coupled with a normal forward/backward chaining mechanism. The prototype expert system also incorporates analytical models (usually written in FORTRAN) into the reasoning process so that it is highly flexible to the problem specificity.
Toward Electronic Work Design BIBA 622-626
  Yung-Hui T. Lee
The dynamic behavior of a musculoskeletal link system in manual lifting is simulated by a mathematical model which contains a non-linear objective function and a set of linear, as well as non-linear constraints. The model was developed based upon the hypothesis that an individual performs the lifting motion following the principle of minimizing mechanical work done. The simulation model demonstrated that the associated differences between the predicted motion and the measured motion is biomechanically feasible and the accuracy is adequate enough with an average U statistics ranging from 0.012 to 0.209.
Some Issues in Collecting Data on Working Postures BIBA 627-631
  Wayne Fisher; Vern Tarbutt
The issues involved in using a pictorial versus a descriptive format to collect data on working posture are reviewed. The use of pictograms to represent limb displacement or joint angle is evaluated and shortcomings in terms of fidelity to the posture being assessed and the facility with which trends and summaries can be extracted are identified. The advantages of a format using only verbal descriptions are described in terms of the flexibility to mix behavioral and anatomical elements, the flexibility to adjust and label measurement intervals and categories, and a layout which facilitates the comparison and summary of data.
Physical Demands of Lineworkers BIBA 632-636
  T. L. Doolittle; Oscar Spurlin; Karl Kaiyala; Dennis Sovern
The occupational classification of electrical transmission lineworker was subjected to extensive job analyses. Physically demanding tasks, that were identified as being bona fide occupational requirements, were studied in depth to elucidate the specific forces necessary to perform them. The tasks were clustered by standard anatomical movements for lifting, pushing and hoisting. Five strength and three work simulation tests were developed to evaluate an individual's capacity for these movements. Ergonomic principles that relate the percentage of an individual's capacity to the frequency at which he or she may safely perform were employed in establishing scoring standards. Metabolic energy requirements were determined for those tasks having a high aerobic demand, and standards for performance were likewise established. Statistical analyses, comparing the test performance of 48 current lineworkers with job success criteria, revealed that the content valid test battery also possesses criterion-related validity.
Similarities and Dissimilarities in the Measurement of Human and Robot Performances BIBA 637-641
  A. M. Genaidy; J. S. Duggal; A. Mital
This paper provides a review and evaluation of the techniques currently used in the measurement of human and robot performances. Furthermore, a strategic model is presented which may assist job designers in the selection process between humans and robots.

Industrial Ergonomics: Let Your Fingers Do the Walking

Hand-Grip Torque for Circular Electrical Connectors: The Effect of Obstructions BIBA 642-646
  S. Keith Adams; Xianqiang Ma
The hand grips of 18 male and 16 female subjects were studied to determine the maximum, clockwise static torque that could be applied to circular electrical connectors under six defined levels of interference and four conditions of interference (types of obstruction) with and without work gloves. The diameters of connectors tested were 0.9, 1.5 and 2.0 in., respectively. Torque strength and required separation were found to be a function of level of interference, condition of interference, connector size, and glove usage. Interference from an adjacent surface to the right or below the grasped connector was less severe than interference from adjacent connectors to the left and right. The greatest interference occurred when adjacent connectors were located to the right, left, above and below the grasped connector. Large connectors permitted greater torque and required less surface-to-surface clearance than small connectors. The use of work gloves increased torque strength slightly but required much larger clearances. Limitations in hand torque strength and required clearances for exertions should be taken into account as ergonomic guidelines for maintainability.
The Effects of Gloves on Grip Strength and Muscle Activity BIBA 647-650
  L. R. Sudhakar; R. W. Schoenmarklin; S. A. Lavender; W. S. Marras
The focus of this research was to investigate how grip strength and forearm muscle force were affected by two types of gloves, rubber and leather. Grip strength was significantly less in the two gloved conditions than in a barehanded condition. However, EMG analysis of muscle activity revealed no significant difference in muscle activity across the gloved and barehanded conditions, indicating that subjects generated maximal exertions in all conditions. Therefore, a certain amount of muscle force is lost in the hand-glove interface while producing maximal grip forces in the gloved conditions. Internal muscle force measurement could thus be used to aid in glove selection for submaximal tasks in industry.
The Effect of Angled Hammers on Wrist Motion BIBA 651-655
  Richard W. Schoenmarklin
This research investigated the range of wrist motion characteristics associated with the ergonomic principle of "bending the tool and not the wrist" as applied to the hammer. It is thought that bending the tool reduces wrist motion, which has been shown in the literature to be a risk factor in hand/wrist disorders, such as carpal tunnel syndrome, tenosynovitis, etc. Bent hammer handles resulted in a tradeoff in beginning and ending positions of the wrist throughout a hammering stroke. Bending the hammer handle to 20 or 40 deg. resulted in significantly less ulnar deviation than a straight hammer, but also increased radial deviation. Overall, the angular deviation from neutral position in the radial/ulnar plane was significantly less for the 20 and 40 deg. hammers than for the straight hammer. This research suggests that angled hammer handles in the range of 20 to 40 degrees could possibly decrease the incidence of hand/wrist disorders caused by the use of hammers.
An Ergonomics Program to Control Cumulative Trauma Disorders in a Manufacturing Environment BIBA 656-659
  Kevin R. Gutekunst; Maxwell T. Fogleman
Cumulative trauma disorders (CTDs) at a manufacturing facility rose greatly from 1985 to 1986 and remained high through 1987. This rise resulted in time lost by injured workers and greater employee compensation for medical expenses. An action team evaluated the problem and suggested both short-term solutions and a long-term program for fewer CTDs. This work included historical research, job observation, videotape, interviews, and direct involvement of the workers. Short-term solutions included work station redesign, developing tailored holding fixtures, and designing ergonomic tools. The long-term program suggested a job rotation scheme, education about the causes and prevention of CTDs, and continued action team involvement. These efforts will continue, and the lessons learned will be applied at other company sites.

Industrial Ergonomics: Lift that Load (MMH 1)

Trunk Muscle Response to Trunk Asymmetry, Velocity, and Load Level BIBA 660-664
  W. S. Marras; G. A. Mirka
A significant amount of epidemiologic evidence suggests that asymmetric motions of the trunk during lifting are related to the risk of low back disorders. However, a void exists in the biomechanical literature which describes how the internal forces of the trunk respond to these motions. An experiment was performed to investigate this relationship. Eighteen subjects were asked to produce lifting motions of the back under highly controlled conditions. Trunk asymmetry, angular concentric and eccentric velocity, torque production, and trunk position were controlled while the activity of ten trunk muscles was observed. This article presents preliminary data from this experiment. Saddle-shaped response surfaces described the reactions or "costs" to the muscles to the various controlled variables. These trends are described and the effects of these trends on spine loading and biomechanical modelling are discussed.
Trunk Muscle Loading in Non-Sagittally Symmetric Postures as a Result of Sudden Unexpected Loading Conditions BIBA 665-669
  Steven A. Lavender; Carolyn M. Sommerich; L. R. Sudhakar; William S. Marras
The present study investigated the effect of warning time and magnitude of an external loading on the trunk muscular response to sudden loading conditions while in a non-sagittally symmetric posture. Eleven subjects were asked to catch falling weights of three magnitudes (3, 6, and 9 kg) with four levels of warning time (0, 100, 200, and 400 ms) in an asymmetric posture. For each of the eight muscles sampled with surface electrodes the integrated electromyographic (EMG) signal was interpreted in terms of its peak value, mean value, onset rate, and lead/lag time with reference to the weight drop. Results show monotonic relations between muscle force and levels of warning time, and muscle force and levels of weight. In addition, muscular forces in the left posterior trunk musculature ranged between two and five times greater than the right posterior trunk musculature in response to sudden loading conditions. This experiment demonstrates how sudden asymmetric loading, and specifically sudden loading without adequate warning time may be involved in the development of low back pain.
A Biomechanical Analysis of Manual Materials Handling Tasks in Restricted Working Postures BIBA 670-674
  Sean Gallagher; Richard L. Unger
The U.S. Bureau of Mines has developed a biomechanical modeling system to examine the stresses on the lumbar spine when lifting in stooped and kneeling work postures utilized by low-seam underground coal miners. This system allows Bureau researchers to digitize two videotaped views (frontal and sagittal) of underground miners performing various lifting tasks under laboratory conditions. These points are then translated into a three-dimensional coordinate system, and a link man (developed from known anthropometry of the subject) is fitted to the 3-D coordinates. The centers of mass for the various links are calculated according to the body type (rotund, muscular, thin, or median) of the subject. Compression results were estimated using a linear programming internal/external load model. The location of the L3 vertebral body center was calculated based upon anthropometric data and morphometric studies of the lumbar spine. Results of the compression and shear force analyses for restricted lifting postures are presented and discussed.
Manual Materials Handling in Unusual Postures: Carrying of Loads BIBA 675-679
  M. M. Ayoub; J. L. Smith
Carrying capacity of individuals was established for four height constrained postures: unconstrained, upright walking, walking in a semi-stooped posture (at 80% of standing height), walking in a full-stooped posture (at 60% of standing height), and crawling (at 40% of standing height). A dynamic strength test, the isoinertial elbow height lift was used to develop prediction models for each of the carrying activities. Carrying capacity decreased as ceiling height decreased. On the average, females handled slightly over 50% of what the males handled under the given task conditions.
Maximum Load Lifting Capacity of Males and Females in Teamwork BIBA 680-682
  Waldemar Karwowski
The main objective of this study was to determine the maximum permissible load lifting capacity (MLCT) of males and females working in teams of two persons. On the average, the maximum capacity of the two-people teams for infrequent lifting of compact loads from floor to the bench height of 89 (cm) was about 105 Kg for young males, and 76 Kg for young females. The ratio between the maximum capacity for a team of two males versus two females, defined as (female/male x 100) was 69.6% (S.D. = 11.06%) with a range from 49.1% to 88.0%. It was proposed that when lifting in teams of two people, the majority of population (95%) should not be required to handle more than 83 Kg for males and 63 Kg for females.

Industrial Ergonomics: Tote that Bale (MMH 2)

Subjective and Biochemical Evaluation of Lifting Tasks BIBA 683-686
  A. Waikar; K. Lee; F. Aghazadeh; S. Subramoniam
Careful selection and training of workers, and good job design have not substantially reduced the incidence of low back injuries. Therefore, reduction in number and severity of such injuries has become a priority concern of many researchers. The specific question addressed by this research was "Are there any discrepancies between the rankings for the lifting tasks based on the subjective estimates of stress at the lower back and the rankings based on compressive force at L5/S1 predicted by the biomechanical model?" The results showed that some of the tasks evaluated to be less severe biomechanically were evaluated to be severe based on the subjective estimation of stress at the lower back.
Utilization of Direct Estimation Method to Determine the Effects of Task Variables on the Capacity to Lift Loads BIBA 687-689
  F. Aghazadeh; K. S. Lee; A. M. Waikar; A. C. Bittner
This paper presents results of a pilot study in which the "direct estimation" method was used to determine the lifting capacity of individuals. Using the capacity of subjects to lift a load from floor to overreach height at frequency of 4 lifts per minute as a base, their capacity to lift under condition of varying task variables was determined. In this study 9 lifting heights, 5 frequencies, and 3 box sizes were used. The amount of load which the subjects were willing to lift was determined by the standard psychophysical methodology. Then the subjects lifted the same loads to various heights at different frequencies using different size boxes. A relationship was established between load lifted to the various lifting heights and the perceived difficulty of the lifting task. A similar relationship was determined for various frequencies and box sizes. An analysis of the results of this methodology reveals that the use of "direct estimation method" provides the effects of task variables on the amount of the lifted load accurately in a short period of time.
Preliminary Physiological and Psychophysical Guidelines for Continuous Lifting Tasks BIBA 690-694
  Ashraf M. Genaidy; Shihab S. Asfour; Tarek M. Khalil
The objective of this research was to study the effects of task parameters on physiological and psychophysical limits for prolonged lifting activities. The results of this study indicate that (1) The endurance time of individuals decreased with the increase of the frequency and the weight of load, and (2) physiological responses are dependent on lifting task parameters.
Isometric Strength Tests: Predicting Performance in Physically Demanding Transport Tasks BIBA 695-699
  Kenneth R. Laughery; Andrew S. Jackson; Gail A. Fontenelle
A study explored the applicability of a battery of four isometric strength tests to steward, utility and warehouse jobs in a company that services offshore drilling and production facilities in the petroleum industry. The jobs involve frequently transporting materials up stairs, a category of tasks not prominent in situations where these tests have previously been applied. A job analysis established critical task requirements such as procedures, weights, distances, sizes of containers, etc. An experiment was then carried out with 25 male and 25 female subjects. The subjects performed two self-paced job-related tasks: transporting a 15.9 kg box up and down stairs and similarly transporting a 22.7 kg box. Measures included heart rate and amount of work performed, which, along with known task parameters was used to calculate work power. Subjects also performed four standard isometric strength tests: grip, arm lift, back lift and arm press. Correlations between job task and strength performance indicated these tests are applicable to jobs with such requirements, thus extending the generalizability of the strength test battery.
The Effects of Asymmetry, Load Level, Start Position and Load Velocity on Lumbar Motion BIBA 700-704
  Gary A. Mirka
In order to completely understand and model the dynamic lumbar spine one must understand not only the forces acting about the spine but also the motions of the lumbar region as well. This study was an investigation into the effects of certain lifting parameters on the motions of the lumbar spine. The effects of asymmetry, load velocity, start position and load weight on the range of motion, angular velocity and angular acceleration of the lumbar spine were investigated in three planes: coronal, sagittal and transverse. The results indicate trade offs between the coronal and sagittal planes as a result of changes in asymmetry and changes in the lifting style as a result of increasing lift velocity. The results also indicate that the location in time of the peak accelerations are varied as a result of different lifting conditions.

Industrial Ergonomics: Industrial Potpourri

Operational Assessment of Simulator Fidelity in the Nuclear Industry BIBA 705-709
  Christopher Plott; Jerry Wachtel; K. Ronald Laughery
The Nuclear Regulatory Commission (NRC) has recently developed a procedure for inspecting nuclear power plant control room simulators. These inspections will ensure that the simulator has sufficient fidelity to produce an appropriate medium for the conduct of operator licensing examinations. The difficulty in obtaining objective data for the assessment of fidelity, particularly for transient or accident events, requires that the inspection be performed primarily from a behavioral perspective rather than a strictly engineering perspective. This paper briefly describes the procedure developed.
Do Those Scanners Really Make a Checkers Life Easier? BIBA 710-713
  John K. Schmidt; Glen E. Gotschall; Salvatore P. Schipani; Kragg P. Kysor
The advent of modern optics technology has decidedly changed the face of inventory control. It is now commonplace to see optically read "bar codes" on things. One popular application has been in supermarkets. Generally, optical scanners are used to read "UPC" labels that are linked with price and inventory information databases, that respectively permit automatic pricing and inventory monitoring. This technology is also contended to eliminate fatigue caused by searching for prices and entering them into a cash register keyboard. However, along with this benefit comes a drawback, the physical overload caused by repetitively handling items, grabbing and manipulating them to properly set the bar code over the scanner, scanning the items by passing them in an extended position over a optical reader (sometimes more than once), and placing them beyond the location of the optical reader. The present paper examines three optical scanner stations and proposes various ergonomic design changes to make them more well suited for checkout personnel.
NCR 7824 Scanner/Scale: An Ergonomic Solution for the Retail Checkout Environment BIBA 714-718
  Mark S. Hoffman
Barcode scanning has been instrumental in increasing user productivity and has expanded the capture of product information, and inventory control. The Human Factors Group in NCR has been a major contributor to the design of scanners.
   The 7824 Scanner/Scale was introduced in 1986. It was designed to provide an ergonomic solution to excessive lifting to weigh produce and meats during the transaction process. This product filled a growing market in customer service; that is to weigh produce and frozen meats within the transaction process rather than require customers to purchase prepackaged fresh foods.
   The success of the 7824 exceeded expectations because of the influence of ergonomics on market demand. Throughput performances for weighed items improved from 2.1 to 3.4 seconds per item, depending upon workstation configurations. Improvements in throughput are attributed to reductions in physical and psychological workload.
Physiological Responses and Subjective Discomfort of Simulated Whole-Body Vibration from a Mobile Underground Mining Machine BIBA 719-723
  Thomas G. Bobick; Richard L. Unger; Sean Gallagher; Diane M. Doyle-Coombs
The U.S. Bureau of Mines has developed an in-house facility to evaluate selected effects of whole-body vibration (WBV) levels experienced by underground mobile equipment operators. Vertical vibration data were collected from a coal haulage vehicle via a uniaxial accelerometer attached to the machine frame under the operator's seat. Data were analyzed and processed so a computer-controlled platform could approximate the vibration signals. Eight men (35.5 yr 1 6.5 SD) participated in a pilot study to evaluate the effects of shock and WBV on heart rate (HR), blood pressure (BP), and subjective discomfort. Subjects were exposed to vibration for 30-min periods while seated in a typical seat (backrest angle at 90-degrees of 130-degrees that was plain steel or modified with 2 in foam padding. Subjects repeated the same protocol on a separate day, without the vibration. Results indicated the vibration significantly increased the HR (p < 0.05) increased significantly. Seatback angle had no significant effect on any of the dependent measures.
A New Keyboard with Chorded Ternary Keys BIBA 724-726
  Karl H. E. Kroemer; Fadi A. Fathallah; Lawrence W. Langley
A new keyboard has been used in preliminary tests. Each key has 3 state conditions ("ternary key") and is moved by horizontal displacement of the fingertip, usually together with another key ("in "chords"). Little is known about the usability of such a Ternary Chord Keyboard (TCK) from previous experiments. Pilot tests indicated fast performance with a TCK.

Industrial Ergonomics: Panel

Designing Shift Work Systems to Improve Performance and Alertness: What Do We Know and What Do We Need to Know? BIBA 727-728
  Roger R. Rosa; Timothy H. Monk; Michael H. Bonnet; Charmane Eastman; Donald I. Tepas; Richard R. Bootzin; James K. Walsh; James C. Duchon
Approximately 20% of the full-time non-farm workforce in the United States is employed on work systems using schedules other than a fixed day shift of 8 (or less) hours duration. Similar world-wide estimates have been made for industrialized countries by the International Labor Office. Work schedules grouped within these systems include permanent night shift work, rotating shift work, and regular work on shifts of greater than 8 hours duration. A number of factors encourage the use of these systems: many new industrial processes require continuous staffing; the number of industrialized countries is increasing; capital equipment costs can often be reduced by increasing or changing the hours of operation; many workers are interested in a workweek of less than five days; and, there has been a general increase in the demand for around-the-clock services.

International Technology Transfer

Myth and Reality in Technology Transfer: The Client-Consultant Relationship in Context BIBA 729-733
  Peter F. Beckschi; Richard E. Redding
Technology transfer is a process often obscured by different styles of human interaction which affect the transfer of information, skills and behaviors. Unless the human factors aspects of the client-consultant relationship are addressed, the process can result in frustrated recipients than can least afford failure, particularly in developing countries. Technology transfer is oftentimes sabotaged at an early stage without any hope of achieving project objectives. The authors contend that early model development and planning in the consultation phase will ameliorate many obstacles to transfer. A consulting model for technology transfer which incorporates systemic, cognitive, and behavioral considerations is proposed.
Deficiencies of Anthropometrical and Osteometrical Data Bases for Technology Transfer Work BIBA 734-738
  Rose Oldfield Hayes
Anthropometrical and osteometrical data bases have deficiencies which, when used without consulting an experienced physical anthropologist, skeletal biologist or anatomist, result in poor designs for technology transfer, place target populations at high risk and/or constrain projected productivity. These deficiencies are due to technical inadequacy, sampling and non-sampling error, population differences, differential maturation, ethnic variation, universal growth, environmental influences and gender differences. The development of a perpetual computer-based universal data bank is recommended for international technology transfer work, as well as for medical research and practice, industrial design, government programs and military requirements.
A Comparison of the Religious and Cultural Roots of Management Practices in Four Nations BIBA 739-743
  Paul R. McCright; R. Venkatesh
The behavior and motivation of business managers are influenced by the values of the surrounding culture. The norms of the social and cultural system are influenced by the behavior and requirements of the business. The purpose of this study is to present one view of why management practices in other countries are different from those in the United States. The general thesis of this study is that management practices in any nation's culture are deeply rooted in the historical and religious origins of that nation's culture. Literature covering management practices and national cultures is reviewed. This study shows that any change in management practices should give careful consideration to the existing culture.
Technology Transfer in Developing Countries: The Case of the Burundi Peat Stove BIBA 744-747
  Cynthia L. Tobias
Due to the severe deforestation and subsequent shortage of the traditional cooking fuels, firewood and charcoal, and to the absence of any other native energy resources, Burundi looked to its vast peat reserves as a potential alternative fuel. This project sought to evaluate the receptivity of urban women in Bujumbura, the capital, to a change in their primary cooking fuel from charcoal to peat. A household energy use survey was conducted to determine habits and preferences. A prototype very low cost peat cooking stove was then built in several households and subsequently modified to suit local practices. Overall acceptance was found to be generally good, and is partly attributable to the intense involvement of users in the design and testing process.