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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 and Ergonomics Society 39th Annual Meeting 1995-10-09

  1. HFS 1995-10-09 Volume 1
    1. WORKSHOPS
    2. PRESIDENTIAL ADDRESS
    3. AEROSPACE SYSTEMS: Aviation Displays [Lecture]
    4. AEROSPACE SYSTEMS: Aviation Safety [Lecture]
    5. AEROSPACE SYSTEMS: [Lecture]
    6. AEROSPACE SYSTEMS: Tools for Human Performance Enhancement in Aviation Maintenance [Symposium]
    7. AEROSPACE SYSTEMS: Automation and Workload [Lecture]
    8. AEROSPACE SYSTEMS: Panel
    9. AEROSPACE SYSTEMS: The Benefits of Auditory Spatial Information in Visual Processing [Symposium]
    10. AGING: Age-Related Differences in Cognitive Functioning [Lecture]
    11. AGING: Evaluating Products for Usability by Older Consumers [Lecture]
    12. AGING: Driving and Retirement Activities [Lecture]
    13. COMMUNICATIONS: Designing for Dialing: Voice, Screens, and Phones [Lecture]
    14. COMMUNICATIONS: Panel
    15. COMMUNICATIONS: Look, Listen, and Touch Interfaces for Communicating [Lecture]
    16. COMMUNICATIONS: Human Factors Issues and the Internet II [Symposium]
    17. COMMUNICATIONS: Panel
    18. COMPUTER SYSTEMS: Expertise in Computer Systems [Lecture]
    19. COMPUTER SYSTEMS: Individual Differences and Strategies When Using Computers [Lecture]
    20. COMPUTER SYSTEMS: Real-World Issues for Computer Systems [Lecture]
    21. COMPUTER SYSTEMS: Human Factors Issues and the Internet I [Symposium]
    22. COMPUTER SYSTEMS: Human-Computer Interaction [Lecture]
    23. CONSUMER PRODUCTS: Design Guidelines and Measurement Tools in Product Design [Lecture]
    24. CONSUMER PRODUCTS: Children: Design Perspectives for a Small World [Lecture]
    25. CONSUMER PRODUCTS: Culture, Perception, and People in Product Design [Lecture]
    26. CONSUMER PRODUCTS: Product Information: Risk, Culture, and Warnings [Lecture]
    27. CONSUMER PRODUCTS: Ergonomic Design of Input Devices [Lecture]
    28. EDUCATORS' PROFESSIONAL: Panel
    29. EDUCATORS' PROFESSIONAL: Tools and Techniques for Teaching Human Factors and Ergonomics [Lecture]
    30. EDUCATORS' PROFESSIONAL: Panel
    31. ENVIRONMENTAL DESIGN: Office Workstation Design: Micro to Macro [Lecture]
    32. ENVIRONMENTAL DESIGN: Panel
    33. FORENSICS PROFESSIONAL: Forensics Research in Consumer Preferences [Lecture]
    34. FORENSICS PROFESSIONAL: Panel
    35. GENERAL SESSIONS: Debate
    36. GENERAL SESSIONS: Panel
    37. GENERAL SESSIONS: Process Investigation, Fault and Error Diagnosis [Lecture]
    38. GENERAL SESSIONS: Panel
    39. GENERAL SESSIONS: Potpourri [Lecture]
    40. GENERAL SESSIONS: Ecological Interface, Design, and Analysis Issues [Lecture]
    41. GENERAL SESSIONS: Panel
    42. GENERAL SESSIONS: Cognitive Task Analysis: What Is It? Why Do It? [Symposium]
    43. GENERAL SESSIONS: Alternative Format
    44. GENERAL SESSIONS: Panel
    45. INDUSTRIAL ERGONOMICS: Hand and Wrist Analysis [Lecture]
    46. INDUSTRIAL ERGONOMICS: Seated Workstations [Lecture]
    47. INDUSTRIAL ERGONOMICS: Upper Extremity [Lecture]
    48. INDUSTRIAL ERGONOMICS: Lifting Biomechanics [Lecture]
    49. INDUSTRIAL ERGONOMICS: Keyboard Development and Analysis [Lecture]
    50. INDUSTRIAL ERGONOMICS: Lifting and Carrying [Lecture]
    51. INDUSTRIAL ERGONOMICS: Ergonomic Implementation [Lecture]
    52. INDUSTRIAL ERGONOMICS: Panel
    53. INDUSTRIAL ERGONOMICS: Psychophysics [Lecture]
    54. INDUSTRIAL ERGONOMICS: Lifting and the NIOSH Guideline [Lecture]

HFS 1995-10-09 Volume 1

WORKSHOPS

Human Factors: Designing for the Future BIB --
  William W. Banks
Human Factors Methods BIB --
  Alphonse Chapanis; John B. Shafer
Questionnaire Design and Use: A Primer for Practitioners BIB --
  William F. Moroney; Joyce A. Cameron
The Design and Development of Product Warning Systems BIB --
  Gerald M. Goldhaber; Gary M. Richetto
Driver Nighttime Visual Detection of Diffuse or Retroreflective Objects within the Context of Traffic Safety BIB --
  Helmut T. Zwahlen
Exposing and Imposing Cognitive Structure: Applications to Human Factors BIB --
  Nancy J. Cooke; Douglas J. Gillan
Using Computer Simulation in Human Factors -- Theory, Technology, and Sample Applications BIB --
  K. Ronald, Jr. Laughery; Catherine E. Drury
Designing Usable Interactive Voice Response Systems BIB --
  M. Elliott Familant; Robert M. Schumacher
Cost-Effective Trends in Usability Evaluations BIB --
  Arlene F. Aucella
A Primer on the Design of Experiments with Human Subjects BIB --
  Richard W. Pew
Lighting and Vision as Ergonomic Issues in the Workplace BIB --
  Jeffrey R. Anshel; Terry E. McShane
Graphic Design for Advanced User Interfaces BIB --
  Aaron Marcus
Prevention of Cumulative Trauma Disorders: Fundamental and Current Ergonomic Issues BIB --
  Karl H. E. Kroemer
Cognitive Task Analysis BIB --
  Gary A. Klein; George L. Kaempf
Preparing for BCPE Certification BIB --
  Paula Sind-Prunier
Integrated Cognitive/Behavioral Task Analysis in Real-Time Domains BIB --
  Wayne W. Zachary; Joan M. Ryder
Using the Internet as an Information Resource BIB --
  William H. Cushman

PRESIDENTIAL ADDRESS

HFES: Historical Trends, Current Status, and Future Challenges BIB --
  F. Thomas Eggemeier

AEROSPACE SYSTEMS: Aviation Displays [Lecture]

A Comparison of Two Head-Up Display Formats Used to Fly Curved Instrument Approaches BIBA 1-5
  John M. Reising; Kristen K. Liggett; Thomas J. Solz; David C. Hartsock
With the advent of the Global Positioning System (GPS), pilots will be able to fly curved instrument approaches. Since current head up display (HUD) symbology was not specifically designed to present this curved information, a study was conducted to determine the most effective set of HUD symbology to assist pilots in flying curved approaches. The military standard HUD symbology was compared with the Pathway HUD format. Dependent measures collected for the comparison were root mean square (RMS) course deviations, RMS altitude deviations, and RMS airspeed deviations. Results showed that there was a significant difference in pilot performance for all dependent measures -- subjects performed better using the Pathway HUD format than the standard HUD symbology in all cases. Pilots comments attributed the advantage of flying the Pathway HUD format to the fact that they could see their route in the form of a highway from their present position to a point 45 seconds into the future. This allowed them to anticipate necessary control movements.
Three-Dimensional Displays for Terrain and Weather Awareness in the National Airspace System BIBA 6-10
  Bradley Boyer; Margaret Campbell; Patricia May; David Merwin; Christopher D. Wickens
Three experiments are reported in which participants (air traffic controllers, Experiments 1 and 2; pilots, Experiment 3) were required to guide an aircraft around the hazards of terrain (Experiment 1) and weather (Experiments 2 and 3), using either 2D (planar) or 3D (perspective) displays. In Experiment 2, air traffic controllers, but not pilots, were less accurate in projecting tracks around terrain with the 3D display than with the 2D display. In Experiment 2, there was little difference between display formats in their ability to support safe vectoring around weather. In Experiment 3, pilots took slightly longer to plan a route around weather with the 3D display, and did so with equivalent accuracy to the 2D display. In all three experiments, the 3D display supported creation of paths that were slightly longer, and skirted the hazard by a wider margin than did the 2D display.
Navigation Display Integration in the General Aviation Environment: Performance using the Horizontal Situation Indicator BIBA 11-15
  Dennis B. Beringer; Howard C., Jr. Harris
Much effort has been invested in examining integrated instrumentation for advanced aircraft cockpits, but little comparable effort has been directed toward the greatest number of aircraft presently flying -- those in the general aviation environment. This study examined the benefits of a simple and widely available integrated instrument, the horizontal situation indicator (HSI), in the performance of simple navigation and orientation tasks by private pilots. Tested in the context of the multiple-processor Basic General Aviation Research Simulator (BGARS), pilots exhibited significantly fewer navigational reversals and orientational errors when using the HSI (in comparison with their performances when using the traditional VOR and Directional Gyro combination). These results were consistent with but even more definitive than an earlier sample of instructor pilots. Similar benefits in procedural error reduction were also found when instrument index markers, or "bugs," were used as short-term memory aids.
Micro Saint Modeling of Visual Displays and Controls Consoles BIBA 16-19
  Sandra M. Eisenhut; Robert J. Beaton
An experiment was conducted to evaluate the feasibility of using a predetermined time system (PTS) with the simulation model Micro SAINT as a method for making design decisions for a navy electronic interactive display and control console. Prototypes for different configurations were created using a Macintosh workstation. Configurations varied across two levels of symbol set, color condition, and screen format for three different target density scenarios. A Micro SAINT simulation model, emulating a single integrated task performed by the operator for all 24 prototype configurations, was constructed. The model was validated by regressing predicted performance scores on actual performance scores obtained from six subjects operating the prototypes. The model also successfully predicted the performance of a second group of six subjects. Although the questions of how to acquire standard deviation data and task time distributions remain, the use of a PTS in network simulation modeling can provide objective data for console designs without incurring the high costs associated with actual prototype construction and testing.

AEROSPACE SYSTEMS: Aviation Safety [Lecture]

Releasing the Hook on the Copilot's Catch 22 BIBA 20-24
  Robert O. Besco
The P.A.C.E. operational methodology presented here is designed to assist subordinate crew members in resolving the basic question of the junior airman: "To Intervene or Not to Intervene?." The P.A.C.E. system has unraveled "The Copilot's Catch 22: You are damned if you ignore the Captain's mistakes; you are damned if you do something about them."
   The four operational procedure steps of P.A.C.E. establish a systematic intervention progression of inquiries to reduce risks at each level of the sequence. The P.A.C.E. skills enable subordinate flight crew members to use proven operationally based procedures to effectively intervene when a Captain is not performing up to reasonable professional standards.
   P.A.C.E. procedures have been developed from case studies of voice recorder transcripts of National Transportation Safety Board aircraft accident reports. The P.A.C.E. methodology provides the skill and knowledge to implement new, operationally relevant components into Crew Resource Management training for each individual organization.
General Aviation Airplane Accidents Involving Spatial Disorientation BIBA 25-29
  Rudolf G. Mortimer
National Transportation Safety Board accident data for 1983-1991 were used to compare those general aviation accident cases that involved spatial disorientation (SD) with all others. About 2.1% of general aviation airplane accidents involved SD. Those accidents were associated with low ceilings, restricted visibility, precipitation, darkness and instrument flight conditions. Pilots in certain professions, particularly those in business, were more involved in SD accidents. Pilots in SD accidents were more often under pressure, fatigue, anxiety, physical impairment and alcohol or drugs. The pilots' total and night flying experience were inversely related to involvement in SD accidents. Spatial disorientation accidents accounted for a small number of crashes, but they were very severe -- fatalities occurred in 92%, they accounted for 9.9% of the fatal accidents, 11% of the fatalities and in 95% the aircraft were destroyed. The results suggest that the pilots in SD accidents lacked the flight experience necessary to recognize or cope with the stimuli that induce SD, which was compounded by fatigue, alcohol/drugs or pressure and other psychological and physical impairments. Specific exposure to conditions leading to SD in training of general aviation and all pilots should be evaluated to help them to recognize it, and the techniques used by experienced pilots to combat its onset and effects should be studied and used in training. Improved human factors engineering of the cockpit instrumentation is also needed.
A 10-Year Overview of USAF F-16 Mishap Attributes in the USAF from 1980-89 BIBA 30-34
  Dwight A. Holland; James E. Freeman
The F-16 Falcon jet fighter is a marvel of engineering. Having been in operational United States Air Force service since approximately 1980, this fly-by-wire aircraft can climb vertically, sustain a 9-G turn without the loss of airspeed, and fly greater than the speed of sound. With such capabilities, this aircraft was originally designed and conceived of as a daylight air-to-air "dog-fighting" pilot's dream. As time has passed, the F-16 aircraft has been tasked with carrying out much more diverse missions than only day air-to-air combat. The aircraft and highly-trained pilots that fly it now accomplish additional missions such as day and night ground attack. An examination of ten years of USAF Safety Center accident data revealed that the F-16 aircraft had 59 Class A operational mishaps during this period. This was the highest number for any single-seat fighter-attack aircraft, and second only to the Aggressor's "Red Flag" F-5 per 100,000 hours of flight time (Class A Accident Rates: F-16 2.86 v. F-5 4.76). Incidentally, about 73% of the Royal Netherlands Air Force pilots reported that they were more susceptible to spatial disorientation and loss of situation awareness in the F-16 compared to other fighter aircraft that they had flown. After 11 years of operational experience, 21 of 210 of the Netherlands' F-16 aircraft were destroyed. A detailed examination of the USAF database revealed that a host of human factors issues are pertinent to the F-16 such as the loss of situation awareness, spatial disorientation, G-induced loss of consciousness, etc.; all of which contributed heavily to the accident rates cited for this aircraft. Additionally, cockpit design issues relatable to man-machine interfacing present human factors challenges to the pilot as well depending upon the mission scenario. The majority (53%) of F-16 accidents occurred during low-level or maneuvering flight. About 20% of the F-16 mishaps happened during the takeoff or landing phase of operations. Over 60% of the accidents were deemed by investigating officers to have "channelized attention" as a definite contributor to the mishap rate. Other human factors issues such as task oversaturation, distraction, and a variety of spatial disorientation problems contributed to many of the accidents also. Cockpit improvements, research, better training/awareness programs and Ground Collision Avoidance Devices (GCAS/PARS) are all suggested as methods to reduce future F-16 Falcon accident rates.
The Effects of Positive Acceleration on Cognitive Performance: Big G -- Little Know BIBA 35-39
  Mark W. Scerbo
Researchers have been studying the effects of acceleration on humans for over 50 years. In that time we have acquired much information about the effects of positive Gz on human physiology, and yet, we know very little about its effects on cognitive abilities. The purpose of the present paper is to underscore the need for additional research in this area. First, a description of the G environment is presented. This is followed by a brief review of some of the relevant literature on psychomotor performance and reaction time. The papers ends with a survey of topics that beg experimental attention using the information processing model as its guide.

AEROSPACE SYSTEMS: [Lecture]

Evaluation of Computer-Based Progress Indicators in the Missile Launch Control Center BIBA 40-44
  Terence S. Andre; A. Reza Pouraghabagher
Missile crew members are subject to certain inefficiencies in the daily operations of maintaining a missile on strategic alert. A computer-based display of procedural information offers several features that can assist a missile crew member. One of these features is the capability to provide progress information (i.e., feedback) to the operator during checklist execution. An experiment was conducted to examine differences between experts and non-experts in three computer-based formats with respect to the current paper-based system. The computer-based formats varied as to the type of feedback provided to the operators. The results indicated that experts responded faster and more accurately than non-experts. Computer-based checklists allowed experts and non-experts to substantially reduce their error rates compared to the paper-based system. User-initiated scrolling time for the computer-based formats had no impact on overall performance.
A Lighting and Visibility Evaluation of the Shuttle/Mir Docking Target BIBA 45-49
  Carlos E. Sampaio; Andrea H. Berman; Terence F. Fleming; Lynn A. Backemeyer
As a prelude to the assembly of the International Space Station Alpha, the Space Shuttle will dock with the current Russian Mir Space Station several times. In order to align the docking interfaces, the Shuttle commander will use a camera view of a target mounted inside the Mir docking hatch to determine and to correct misalignment. An evaluation took place at NASA's Johnson Space Center to determine if modifications to the target design resolved previous visibility issues and to quantify the effect of orbital shadows on the commander's ability to perceive target cues. Both the commander and pilot of the first two docking missions participated as subjects. Results of this evaluation showed that target visibility issues were resolved. Critical information was also provided to operations engineers regarding how to deal with orbital shadows during rendezvous. These results assisted ground operations controllers in instructing the STS-63 crew on what image data was required to verify expected on-orbit conditions for upcoming Shuttle/Mir missions.
The Role of Visual Attention in Head-Up Displays: Design Implications for Varying Symbology Intensity BIBA 50-54
  Patricia A. May; Christopher D. Wickens
Twenty pilots from the University of Illinois flew a low fidelity simulator during cruise flight. The intensity of the display symbology was manipulated in three different weather conditions to influence the discriminability of the instrumentation. The symbology was displayed in either head-up or head-down locations, with equivalent optical distances and display formats. Half of the subjects flew with a conformal symbology set, while the other half flew with a partially conformal symbology set. Responses to near and far domain events were measured, and tracking error of the three axes of control was calculated. The results revealed a head-up advantage to the far domain event detection and a head-down advantage to the near domain event detection. Performance in the head-up condition approached that of the otherwise superior head-down condition when an appreciable contrast between the symbology and the background environment was provided. The results are discussed in terms of an effect of the modulation of focused attention.
Vertical Auditory Localization for Spatial Orientation BIBA 55-59
  Mica R. Endsley; S. Armida Rosiles
The use of three-dimensional auditory technology which provides localization of auditory cues presented through headphones is proposed as a means of providing supplemental information to pilots on the spatial orientation of an aircraft. This technique shows promise for reducing accidents due to spatial disorientation associated with high visual load. A study was conducted using Air Force pilots as subjects to determine desirable cue characteristics for accurately localizing auditory cues using this technique. The study examined the use of nine different cue types at each of two frequency levels. It was found that the accuracy of subjects' localization of cues in elevation was greatly enhanced by the use of multidimensional cues which provided redundant elevation information through varying frequencies and distance from the horizon cues in addition to the inherent spatial location information.

AEROSPACE SYSTEMS: Tools for Human Performance Enhancement in Aviation Maintenance [Symposium]

Tools for Human Performance Enhancement in Aviation Maintenance BIBA 60
  William B. Johnson; Meghashyam Gopinath
Human Factors and ergonomics professionals are often asked to "show" how their research has affected on-the-job human performance. They are asked to show measurable changes in human effectiveness and efficiency at work. There is always the demand for HF&E researchers to create procedures and tools that can guide non-human factors personnel to make the "right" human-centered decisions. This symposium will show and distribute such tools that have been designed and tested in an aviation maintenance environment.
   For over six years now, the Federal Aviation Administration Office of Aviation Medicine has conducted an extensive research program centered on human factors in aviation maintenance and inspection. The research program has earned a reputation of demonstrating a "hands-on" understanding of aviation maintenance and maintaining a close working relationship with all segments of the industry.
   The symposium will begin with an overview of FAA-sponsored research results applied to aviation maintenance and safety over the past six years. In the second paper the Human Factors Guide for Aviation Maintenance, completed in 1995, will be described. The third presentation will demonstrate a CD-ROM version of the Guide. The presentation shall also discuss human-computer interface issues pertinent to developing interactive multi-media information systems. The final presentation will show a multi-media software package to conduct ergonomics audits in a variety of industrial environments. The system has evolved from three years of ergonomics audit research in aviation maintenance workplaces.
   Each of the session presentations will demonstrate and distribute HF&E tools to session attendees.
Human Factors in Aviation Maintenance and Inspection: Research Responding to Safety Demands of Industry BIBA 61-65
  William T. Shepherd; William B. Johnson
For over five years the Federal Aviation Administration has conducted extensive research and development to enhance human performance and safety in aircraft maintenance and inspection. Directed by the Office of Aviation Medicine (AAM) the program has engaged in pragmatic research capitalizing on basic scientific principles and a thorough working relationship with all levels of aviation maintenance practitioners. This paper describes a few of the example research products that are currently promoting safety and efficiency in maintenance applications worldwide.
Providing Useful Human Factors Guidance to Aviation Maintenance Practitioners BIBA 66-70
  Michael E. Maddox
The Aloha Airlines B-737 accident in 1989 prompted a general evaluation of aviation maintenance and inspection practices. A consistent finding from the Aloha analyses was that human-factors-related issues played a significant role in the accident. In the intervening period, the FAA Office of Aviation Medicine (AAM) has sponsored a wide-ranging, applied human factors research program. The Human Factors Guide for Aviation Maintenance (the Guide) is the primary vehicle for channeling the results of the AAM's research program into the aviation user community.
   This paper describes the development process of the Human Factors Guide for Aviation Maintenance. We include a discussion of how the existing base of research results has been made accessible and, more importantly, usable to aviation maintenance supervisors and inspectors. We also describe the considerations related to widely disseminating the information and guidance contained in the Guide. We believe this to be the first time that detailed human factors guidance from such a broad topical range has been tailored to a particular, applied, user domain.
The Electronic Human Factors Guide for Aviation Maintenance BIBA 71-74
  Julie A. Jones; T. Kiki Widjaja
Technological advances in the area of computer software, hardware and peripherals have made digital information technology feasible. The Federal Aviation Administration Office of Aviation Medicine has been investigating the application of such technology. The overall goal is to increase accessibility and to improve distribution of Human Factors research reports and information to the aviation maintenance industry. The latest digital documentation project is the Electronic Human Factors Guide for Aviation Maintenance (E-Guide). The E-Guide is a hypermedia version of the Human Factors Guide for Aviation Maintenance (the Guide) which is described elsewhere in this symposium. This paper describes the design goals, key features, and future plans for the E-Guide.
Electronic Ergonomic Audit System for Maintenance and Inspection BIBA 75-78
  Gopinath Meghashyam
This paper describes an ergonomic auditing software system, one of the tools used for performance enhancement of aircraft inspectors. This tool was developed at Galaxy Scientific Corporation, in cooperation with the State University of New York at Buffalo, for the Federal Aviation Administration (FAA). The purpose of the development task was to integrate a variety of ergonomic audit tools into a comprehensive package. This ergonomic auditing system called "ERgoNomic Assessment Program" (or ERNAP), carries out an ergonomic evaluation for maintenance and inspection operations. ERNAP can also be used to help designers build ergonomically efficient procedures and systems. ERNAP evaluates existing/proposed tasks and setups in the application of human factors/ergonomic principles, and suggests ergonomic interventions. The package consists of a user interface, an inference engine, a printing module, and a reference database. The user interface supports user learning, helps guide the user through the steps, describes the less familiar ergonomic principles, allows the user to access on-line help, and is simple to use. The inference engine evaluates the user inputs based on the reference database and different models of analysis. This package maintains consistency with the Human Factors Guide for Aviation Maintenance which is reported within this session.

AEROSPACE SYSTEMS: Automation and Workload [Lecture]

"From Tool to Agent": The Evolution of (Cockpit) Automation and Its Impact on Human-Machine Coordination BIBA 79-83
  Nadine B. Sarter; David D. Woods
In a variety of domains, researchers have observed breakdowns in human-automation coordination and cooperation. One form of breakdown is a lack of mode awareness which can result in 'automation surprises'. These are, in part, related to a lack of adequate feedback on system status and behavior. The need for effective and timely feedback has become even more pressing with the evolution of systems that operate at increasingly high levels of authority and autonomy. In the absence of improved feedback design, however, the gap between required and available information has widened. To explore the impact of this trend towards 'strong yet silent' machine agents, a line of research was conducted on pilot-automation coordination on the Airbus A-320, an aircraft that exemplifies these trends. This research involved a survey of pilots' line experiences with the A-320 automation, observations of transition training to the airplane, and an experimental simulation study on pilots' mode awareness and pilot-automation coordination. The results of this work indicate a trend from mode errors of commission (which represented a more frequent problem on early generation 'glass cockpit' aircraft) to errors of omission. In other words, pilots were more likely to fail to observe and interfere with uncommanded and undesired automation and aircraft behavior. Such errors of omission also seem to have played a role in recent incidents and accidents. They illustrate the need for improved communicative abilities in autonomous and powerful systems to enable them to actively support the coordination between human and machine.
Human Factors Issues in Night Airborne Mine Countermeasures Operations BIBA 84-88
  John W. Ruffner; Richard E. Tullos; Richard C. Muldoon
The U. S. Navy's Airborne Mine Countermeasures (AMCM) mission, performed by the MH-53E helicopter, is characterized by long duration flight at low altitudes and low airspeeds over the water while towing a variety of devices. This mission imposes substantial demands on the pilots and mission crew. Because of its complexity and potential hazards, the AMCM mission is currently performed only during the daytime. The Navy identified a requirement to perform AMCM operations at night and sponsored research to investigate the system and procedural modifications required to accomplish night AMCM operations safely and effectively. This paper discusses the human factors issues identified as part of this research effort and provides specific examples from the AMCM mission environment. A thorough understanding of these issues and how they will impact night AMCM operations is essential for a successful transition from day to night operations.
Hardware and Human Factors Issues for Military Automatic Brightness Controls BIBA 89-93
  Jennie J. Gallimore; James R. McCracken; Janet M. Gerace
Electronic displays have replaced many mechanical displays in aircraft. The "glass" cockpit continues to advance. Electronic displays required adjustment of luminance (often referred to as brightness) and contrast as the ambient environment changes. Requiring pilots to manually control brightness creates additional pilot workload. Instead, automatic brightness controls (ABCs) have been suggested. The purpose of this paper is to summarize a research plan for the development of an ABC for military aircraft.
Prediction of Pilot Subjective Workload Ratings BIBA 94-97
  Anthony J. Aretz; Scott F. Shacklett; Phil L. Acquaro; Derek Miller
This paper investigated potential variables that predict pilot subjective workload ratings. A correlational design was used to regress NASA TLX subjective workload ratings onto four independent variables (the number of concurrent tasks, task type, task combination, and flight experience). A pilot selection simulator was used to present five different flight tasks, in different combinations, to 15 cadets at the USAF Academy. The results indicated the number of concurrent tasks had the largest impact on subjective workload ratings, followed by subjects' flight experience. The data also showed that the effort dimension of the NASA TLX contributed the most variance to the overall weighted workload ratings. The implication for theoreticians and designers is that the number of concurrent tasks, experience, and perceived effort seem to be key contributor to subjective workload ratings.

AEROSPACE SYSTEMS: Panel

Free Flight: Human Factors Implications BIBA 98-102
  Daniel J. Garland; John A. Wise; David W. Abbott; V. David Hopkin; Russell A. Benel; Philip J. Smith
There is a real possibility that the air traffic control system in the United States will change radically in the next decade. One vision -- "free flight" or "free routing" -- is to move most of the responsibility for navigation and separation back to the cockpit and away from ground based air traffic systems. The basic notion of free flight is that each flight would be completely determined by the user, i.e. by some form of airline/pilot combination, and would not need to follow pre-defined airways or altitudes. The airlines would inform the air traffic system of each aircraft's intentions, but would not have to seek any prior air traffic approval. The job of the air traffic system would be to meet the user's requirements but not to suggest what those requirements should be. However, the air traffic system would be expected to collaborate with the airlines to ensure the safe passage of flights and to intervene when aircraft separation requirements are jeopardized or violated. Such a system would bring with it dramatic changes in the roles of all the human members of the aviation system, and as such, would have significant human factors impacts. The goal of this panel will be to identify and discuss some of those issues.

AEROSPACE SYSTEMS: The Benefits of Auditory Spatial Information in Visual Processing [Symposium]

The Benefits of Auditory Spatial Information in Visual Processing BIBA 103
  Thomas Z. Strybel
Techniques for the production of externalized, "3-dimensional" sound images for acoustic signals presented via headphone were developed in the past decade. These 3-D sound systems simulate both interaural time and intensity cues, and cues based on the action of the pinnae on incoming sound sources (e.g. Wenzel, Wightman and Foster, 1988). It has been anticipated that these 3-D sound systems would be useful in the cockpit and other work settings because they provide a natural method directing an operator to some event in the environment. This symposium is a progress report on research which has either examined potential applications of 3-D sound systems in the workplace, or attempted to understand how auditory spatial cues direct visual attention. Researchers at NASA Ames Research Center and Wright Patterson Air Force Base have identified cockpit tasks that can benefit from auditory spatial cueing. Some of these tasks include gate identification, blunder avoidance, and traffic identification of approaching and receding targets.
   The benefits of audio spatial cueing are usually measured by determining the reduction in search latency that is realized when searching for targets with and without auditory spatial cues. These benefits can be explained by the findings that both simple detection and identification times are faster and more constant across the frontal hemifield when auditory spatial cues are presented with the target. Furthermore, for sounds presented in the central visual field, auditory spatial cues can either supplement or substitute for abrupt visual onsets in directing visual attention.
   Wenzel, E. M., Wightman, F. L. and Foster, S. H. (1988). A virtual display system for conveying three-dimensional acoustic information. Proceedings of the Human Factors Society 32nd Annual Meeting, 86-90.
Aurally Aided Detection and Identification of Visual Targets BIBA 104-108
  David R. Perrott; John Cisneros; Richard L. McKinley; William R. D'Angelo
The experiments described in this report provide baseline performance measures of aurally directed detection and search for visual targets in an observer's immediate space. While the simple target detection task was restricted to the frontal hemi-field (extending 180 degrees in azimuth and 150 degrees in elevation), visual search performance (discrimination of which of two light arrays was present on a given trial) was evaluated for both the frontal and rear hemi-fields. In both tasks, the capacity to process information from the visual channel was improved substantially (a 10-50 percent reduction in latency) when spatial information from the auditory modality was provided concurrently. While performance gains were greatest for events in the rear hemi-field and in the peripheral regions of the frontal hemi-field, significant effects were also evident for events within the subject's central visual field. The relevance of these results to the development of virtual 3-D sound systems is discussed.
Auditory Spatial Cueing in Visual Search Tasks: Effects of Amplitude, Contrast, and Duration BIBA 109-113
  Thomas Z. Strybel; Jan M. Boucher; Greg E. Fujawa; Craig S. Volp
The effectiveness of auditory spatial cues in visual search performance was examined in three experiments. Auditory spatial cues are more effective than abrupt visual onsets when the target appears in the peripheral visual field or when the contrast of the target is degraded. The duration of the auditory spatial cue did not affect search performance.
Head-Up Auditory Display Research at NASA Ames Research Center BIBA 114-118
  Durand R. Begault
The use of spatialized ("3-D") audio techniques for head-up auditory displays for commercial aircraft has been investigated at NASA Ames Research Center since 1989. Results from two completed studies are presented, where a 3-D audio Traffic alert and Collision Avoidance System (TCAS) was designed and evaluated in a full mission simulation context. An experiment-in-progress evaluates the application of 3-D audio for gate identification and collision avoidance with other aircraft, as part of NASA's Terminal Area Productivity-Low Visibility Landing and Surface Operations (LoVlaso) program.
An Initial Study of the Effects of Three-Dimensional Auditory Cueing on Visual Target Detection BIBA 119-123
  Richard L. McKinley; William R. D'Angelo; Michael W. Haas; David R. Perrot; W. Todd Nelson; Lawrence J. Hettinger; Bart J. Brickman
Developments in virtual environment technology are enabling the rapid generation of systems that provide synthetic visual and auditory displays. The successful use of this technology in education, training, entertainment, and various other applications relies to a great extent on the effective combination of visual and auditory information. Little is known about the basic interactions between the auditory system and the visual system in real environments or virtual environments. Therefore, the purpose of the current study was to begin to assess the effectiveness of various combinations of visual-auditory information in supporting the performance of a common task (detecting targets) in a virtual environment.

AGING: Age-Related Differences in Cognitive Functioning [Lecture]

Age, Expertise, Structural Similarity, and Time-Sharing Efficiency BIBA 124-128
  Pamela S. Tsang; Tonya L. Shaner
Interactive effects of age, expertise, and structural similarity on time-sharing efficiency were examined. Half of 90 subjects who ranged from age 20 to 80 years were nonpilots. The other half were pilots who were considered to have expertise in time-sharing. Five dual tasks were selected to represent various cognitive aspects of flight performance and to represent various degrees of structural similarity defined by Wickens' multiple resource model. Several main findings were of note. One, time-sharing efficiency increased as structural similarity decreased. Two, time-sharing efficiency decreased with increased age. Three, pilots had higher level of time-sharing efficiency than nonpilots. Four, expertise in time-sharing appeared to be able to moderate some of the deleterious age effects. Theoretical and practical implications of these findings were considered.
Age Differences in Perception of Workload for a Computer Task BIBA 129-133
  Sara J. Czaja; Joseph Sharit; Sankaran N. Nair
Research concerned with age and work activities is an important area of investigation since the workforce is aging and there are concerns regarding economic dependency as well as labor shortages for certain occupations. Previous work by the research team indicated age differences in the performance and perceptions of task difficulty and fatigue for three simulated real-world computer tasks. This study is an extension of that research and is investigating the extent to which age differences in performance and perceptions of workload are moderated by experience and task practice. One hundred and twenty subjects aged 25 yrs. to 75 yrs. performed a real-world data entry task. Data will be presented regarding age differences in the perception of workload, stress, discomfort, and attitudes towards computers. The implications of these results for design interventions will be discussed.
Visual Search and the Older Adult: Not All is Lost BIBA 134-138
  Darryl G. Humphrey; Arthur F. Kramer; Donnelle R. Schneider
Plude and Doussard-Roosevelt (1989) reported age-related search slope differences in a conjunction search task but not in a feature search task. According to Feature Integration Theory (Treisman & Gelade, 1980), older adults may suffer an impairment in the feature integration mechanism required for conjunction searches. We extend this work by examining age-related differences a series of feature, conjunction, and triple conjunction search tasks. The results of the feature and conjunction search tasks support the previous findings. However, the results of the triple conjunction search task suggest that the conjunction search impairment is not universal. As the triple conjunction search results are difficult to accommodate within Feature Integration Theory, the results are discussed within the framework of the Guided Search model of visual selective attention.
Effects of Aging on Working Memory and Workload BIBA 139-142
  Starr Lynn Fox; F. T. Eggemeier; David W. Biers
The current study investigated the effects of aging on working memory and mental workload. Subjects performed a Brown-Peterson memory task using simulated air traffic controller/pilot communications. Perceived mental workload was measured using the NASA-TLX rating scale. Results revealed no significant recall performance differences between younger and older individuals. However, workload ratings indicated that older individuals experienced higher perceived workload than younger individuals. These findings suggest subjective workload ratings may be sensitive to age-related differences not demonstrated by performance measures.

AGING: Evaluating Products for Usability by Older Consumers [Lecture]

Enhancing Label Readability for Over-the-Counter Pharmaceuticals by Elderly Consumers BIBA 143-147
  Michael S. Wogalter; David A. Dietrich
The most common information source for over-the-counter (OTC) pharmaceuticals is the container label. Most OTC labels contain so much text that the print must be substantially reduced in size to fit the available surface area. As a consequence, people with vision problems, such as the elderly, have difficulty reading the print. Some OTC drugs are being marketed in containers with easy-open caps to facilitate access (but at the same time, reduce child resistance). The increased surface area afforded by the cap design could be used to enhance the labeling. An experiment compared elders' (mean age of 75) evaluations to different label variants. Experimental bottles contained additional labeling attached to the cap that reiterated and extended some of the most important warnings and instructions. The additional labeling of the experimental bottles had print that was larger than the existing back label, and among them, differed in background color. These bottles were compared to two control conditions (one with the original store-bought label and one with the back and side labels removed). Participants ranked the containers on six dimensions (e.g., noticeability of the label, willingness to read the label, willingness to purchase the product). Results showed that the participants preferred the bottles with the additional cap labeling and most preferred the one with the distinctive fluorescent green color. Implications of these results are discussed.
Accessible Remote Controls for Older Adults with Mildly Impaired Vision BIBA 148-152
  Juli J. Lin; Robert C. Williges; Douglas B. Beaudet
A three-phase methodology was used to design an accessible photo CD player for older adults with mildly impaired vision. During Phase I of the study, critical barriers to a photo CD player were identified that prevent older users with presbyopia from operating this product. These barriers included small Remote Control Unit (RCU) labeling, low label-background contrast, and inadequate feedback from the player system. During Phase II, cost-effective solutions were identified through research into existing literature and available technologies. Phase III evaluated the efficacy of these design modifications on both the accessibility and usability of the photo CD player. The results of the Phase III empirical study indicated that enlarging a RCU and using high contrast labeling significantly improved accessibility. Overall, these results support the use of such a three-phase methodology to design accessible consumer products for users with special needs.
Training New Technology: Automatic Teller Machines and Older Adults BIBA 153-157
  Brian A. Jamieson; Elizabeth F. Cabrera; Sherry E. Mead; Gabriel K. Rousseau
The purpose of the present study was to assess the benefits of providing on-line training for an automatic teller machine (ATM). An ATM simulator was developed for the study, and older adults (65-80) served as the subjects. Subjects were assigned to one of two conditions. Half of the subjects were given a written description of how the ATM worked. The other half went through an on-line tutorial, which showed them how to perform transactions on the simulator. After performing 30 transactions on the simulator, subjects were transferred to a new ATM simulator that was topographically different. The subjects who received the on-line tutorial performed more transactions correctly during acquisition, and were better able to transfer their skills to a different ATM simulator and to novel transactions.
Design of a Touch Screen Microwave Oven for Older Consumers BIBA 158-162
  Beth A. Loring
The purpose of this study was to add to the knowledge of older consumers and their use of electronic products. The work involved redesigning a microwave oven by employing a touch screen interface. This provided a simpler panel with limited choices, step-by-step prompts and larger controls and displays. The design was tested for usability with 8 people over 60 and 8 under 60, in comparison to an existing microwave oven. Participants of all ages completed 4 out of 5 sample tasks faster with the touch screen model. The touch screen model was rated easier to learn and use on all tasks. This paper discusses the redesign of the microwave, the usability test, and final design recommendations.

AGING: Driving and Retirement Activities [Lecture]

Distribution of Discretionary Time by Retired People BIBA 163-166
  John A. Modrick; Susan Meyers; Robert Papke
This study is a survey of the activities of retirees of a Fortune 500 manufacturing company. The objective was to provide a baseline description of activities as people adjust to changes associated with retirement and decremental changes of aging. A sample of 40 retirees was interviewed to obtain information on 1) demographics, living conditions, and health; 2) distribution of time over activities of work, recreation, family, and volunteering; 3) changes associated with aging and socio-economic factors. It is intended to provide an activity picture that will be a context for identifying behavioral problems and devices, organizations, and supporting aids to enhance quality of life.
   Respondents represent the gamut of occupations and skill levels, socio-economic conditions, and ethnic diversity characteristics of a large, midwestern manufacturing corporation. The distribution of ages in the retiree population and sample were equivalent. The activities surveyed include reading, watching television, household chores and maintenance, skill or craft hobbies, intentional exercise, care-giving, volunteer work, and work for pay. Analyses include differences and changes in activities as a function of gender, age, length of retirement, health, and living situation. Volunteer work is analyzed in detail concerning type, location of the work, and time spent on it.
Dual-Task Assessment of Age Differences in Mental Workload with Implications for Driving BIBA 167-171
  Carryl L. Baldwin; Frank Schieber
Older drivers constitute the fastest growing segment of the driving population, in terms of both number of drivers and number of miles driven. Accident analyses reveal that older drivers are not able to fully compensate for emerging reductions in perceptual/cognitive capacity. Establishment of a method of assessing older drivers with perceptual/cognitive impairments which place them at risk of accidents is imperative. In this investigation, a subsidiary task of mental arithmetic was demonstrated to be sensitive to age differences in relative mental workload resulting from increased steering task complexity in a simulated driving task. As steering task difficulty increased, verbal response latency to concurrent mental arithmetic problems increased for older, but not younger, participants. Steering error remained stable across single and dual task conditions indicating that the secondary mental arithmetic task did not interfere with steering (primary task) performance. These results provide preliminary support for the use of this assessment technique outside of the laboratory in actual driving situations.
The Relationship of Age and Cognitive Characteristics of Drivers to Performance of Driving Tasks on an Interactive Driving Simulator BIBA 172-176
  Jose H. Guerrier; P. Manivannan; Anna Pacheco; Frances L. Wilkie
Older adults depend highly on the automobile to satisfy their mobility needs. They use the private car for the majority of their trips. However, driving is not without risks for older drivers and those who share the road with them. Drivers 65 and older contribute to more accidents per mile driven than younger drivers except those 18-24 years old. Furthermore, they are more likely to be injured or die as a result of such accidents than their younger counterparts. Current thinking suggests that the cognitive abilities of older drivers may be the best explanation for these accidents. This study investigated the contribution of age and specific cognitive, psychomotor, and perceptual dimensions upon the performance of driving tasks on an interactive simulator. The results suggest that age as such does not explain performance of driving tasks. Rather, age-sensitive cognitive characteristics of drivers provide a better understanding of performance of specific driving tasks.
Effects of Collision Warnings on Braking Response Time of Older and Younger Drivers BIB --
  Gayna Williams

COMMUNICATIONS: Designing for Dialing: Voice, Screens, and Phones [Lecture]

Design Locally, Validate Globally BIBA 177-181
  Erich Elkins; John E. Quinn
A process for developing the user interface and the industrial design for products intended for international markets is presented. The process was derived from lessons learned while developing a business telecommunications device. The device required an interface that was easier to use and a product design that would be attractive to worldwide business users. The design process was based on two iterations of user testing. The first iteration included 51 users from three major U.S. metropolitan areas; while the second had 294 users from four European cities, three U.S., and two Asian. The recommended process requires that multiple competing designs be presented to users for iterative validation and revision before selecting the final design. The competing designs increase the likelihood that cultural differences are met and the best design solution is achieved.
Designing Features for Display-Based Systems BIBA 182-186
  Pamela A. Savage; David R. Millen; Jeanne P. Bayerl
The purpose of this paper is to provide a detailed description of the design process used to identify the optimal implementation of the Caller ID feature for a key/pbx telephone system for small businesses. A multidisciplinary team used an assortment of design methodologies such as: literature reviews, patent searches, competitive analysis, feature simulations, focus group research, focused interviews, and usability testing to generate their final design recommendation, which has recently been awarded a patent. Specifically, this paper will focus on: 1) the competitive analysis that included a product comparison and best-in-class analysis of three commercially available Caller ID products, 2) focus group research in which participants viewed slide show demonstrations of display-based features, made ease of use and feature desirability ratings, and then expressed their views toward the features in structured focus group discussion, and 3) focused interviews with customers who had been given Caller ID display units to trial.
Iterative Design of a Voice Name Dialing Service BIBA 187-191
  Roger B. Garberg
Recent advances in automatic speech recognition (ASR) technology have enabled us to develop the first commercially available voice name dialing service that provides the user with voice control of all aspects of service operation, including training the ASR device, administering the dialing list, and placing calls to listed parties by saying their name. One of the principal challenges in designing the service has involved anticipating the sources of breakdowns, occasions in which the user is compelled to attend to an ASR capability that has failed to respond as expected. Iterative design-and-test studies have produced a service judged fun and easy to use in recent commercial trials. This paper describes the studies and the design details that have enabled us to avoid or accommodate a variety of potential breakdowns, and so realize the new potential of ASR in telecommunication applications such as voice name dialing.

COMMUNICATIONS: Panel

Customers with Disabilities: The Ultimate Usability Challenge BIBA 192-193
  Jim Tobias; Marilyn Benoit; Ellen Francik; Susan Palmer
This panel will discuss both technical and organizational issues regarding guaranteeing that new telecommunications services are as accessible as possible to customers with disabilities. The panelists represent several large telecommunications companies and come from a variety of backgrounds and corporate organizations. Emphasis will be placed on the importance of universal design rather than creating specialized products.

COMMUNICATIONS: Look, Listen, and Touch Interfaces for Communicating [Lecture]

The Minimal Remote: A Standard Input Device for Consumer Interactive TV BIBA 194-197
  Joel S. Angiolillo
This paper is a polemic and a plea. The almost complete lack of user interface conventions in consumer entertainment equipment, if carried over to the new world of Consumer Interactive TV (CITV), will result in chaos and confusion for CITV users as well as developers.
   Interface designers of computer software know exactly what sort of input devices a computer user will have, namely, a QWERTY keyboard with 83 to 103 keys, including 10 to 12 function keys, a control key, escape key, a tilde, slash, and so on. In addition, the user will have a mouse (or an equivalent pointer) with two unlabeled buttons, one for "selection" and the other for "menu." This standardization of keys and labels allows great freedom in the design of software because software can be designed independently of any hardware. It also permits users to move from system to system with no relearning of the basic capabilities of the physical input device (albeit, how these "key primitives" are assembled into commands may require significant relearning.)
   As a community devoted to reducing the anxiety levels of consumers, our goal should be to create the same environment for CITV, a world that is a stranger to conformance and convention today. A basic set of core controls should be present on all CITV devices. We must define these core controls carefully because they will be the tools by which the future shape of CITV applications will be cut. In this paper, I argue that all CITV input devices should include
  • a pointer (with associated select key),
  • a twelve button dial pad, and
  • four function keys. Individual input devices can enhance this set of "core controls" (as a keyboard can add a separate number entry pad), but they should not omit any of them. I call this CITV input device with only the basic set of core controls a "Minimal Remote."
  • On the Reproduction of Motion Parallax in Videocommunications BIBA 198-202
      Martin Bocker; Detlef Runde; Lothar Muhlbach
    The paper addresses the question whether reproducing motion parallax increases the extent of telepresence in videocommunications. Motion parallax is defined as the change of the view due to the observer's movements. It was hypothesized that reproducing motion parallax (a) leads to more precise depth judgments by providing further depth cues, (b) allows 'interactive viewing', i.e. the observer can actively explore the visual scene by changing his/her position, and (c) compensates for stereoscopic "apparent movements". In a Human Factors study, two videoconferencing set-ups providing motion parallax (one stereoscopic and one monoscopic version) were compared with two set-ups (monoscopic and stereoscopic) without motion parallax. Each set-up was used and rated by 32 subjects. The results supported the hypotheses only in part. Even though there was some evidence for more "spatial presence" and for a greater explorability of the scene through motion parallax, the compensation of apparent movements could not be achieved.
    Automatic Speech Recognition Applications: A Study of Methods for Defining Command Vocabularies BIBA 203-207
      Roger B. Garberg
    Phoneme-based automatic speech recognition (ASR) technology enables designers to easily create custom command words or phrases that users can employ to request service operations. In this paper, I report results from two experiments concerning important dimensions of these ASR command vocabularies, including command naturalness/appropriateness and command recallability. Ease of recall is a critical dimension for assessing ASR commands used in multi-step applications since service subscribers may be engaged in several different cognitive activities that divide attention. Yet techniques for measuring command recallability can be difficult to implement owing to the time required for data collection and analysis. Results of these studies indicate that the dimension of command "naturalness" and memorability are closely related: under appropriate conditions, the simple procedures associated with measuring command naturalness or appropriateness can predict retrievability of command expressions.
    Do Human Factors Color Recommendations Have Any Practical Value? BIBA 208-212
      M. Elliott Familant; Mark C. Detweiler
    This study surveyed 342 directory-assistance (DA) operators regarding the text and background colors they used to display directory listings on their computer workstations. Color combinations were observed in use, recorded, and scored based on independent, published subjective ratings of color comfort and edge sharpness. Operators also answered a questionnaire that included information about: how often they changed colors and if they had experienced eye problems. No relationships were found between self-reported eye problems and observed color choices. However, operators using color combinations that were scored low on either comfort, edge sharpness, or both, were more likely to change the colors on their screens more frequently. This result provides evidence that independent ratings can provide practical guidance in making color recommendations.

    COMMUNICATIONS: Human Factors Issues and the Internet II [Symposium]

    Human Factors Issues and the Internet II BIBA 213-217
      Cathleen Wharton; Ray Eberts; Joel Angiolillo; Fred Brigham; Beth Givens; Lila Laux; David Neal; Michelle Owens
    The Communications and Computer Systems Technical Groups of the Human Factors Society are sponsoring a Special Symposium about Human Factors Issues and the Internet. During this symposium a series of speakers will provide an overview of the Internet, discuss Internet foundations such as video and graphics, present existing and newly developed application software for the Internet, highlight user needs and concerns for special user populations, and delve into privacy issues in the context of Internet ethics. The Internet, a networked collection of smaller networks, links computers together world-wide. Using basic tools such as Telnet, Gopher, and the World Wide Web, people can use their computers to connect to and access information from all over the world.
       Until recently, most Internet users were from the academic and business arenas. As the price of computers has dropped and access to the Internet has become both more widespread and affordable, people are now able to easily use the Internet from home and for purposes other than those associated with everyday work.
       This rapid expansion of the Internet and growth in user populations have caused human factors professionals to actively seek and investigate key human factors issues on the Internet. Some of the key questions include:
  • Given that the Internet is becoming prevalent in both homes and schools, what
       human factors concerns do we need to concentrate our efforts on now and in
       the future?
  • With the advent of CommerceNet and the increasing desire to both order goods
       and market services using the Internet, what work should we as human factors
       professionals undertake to make such services better?
  • Community networking (the integration of multimedia and network services in
       the home) is being driven by both broadband and narrowband technologies and
       services. How do we as human factors professionals shape such services to
       truly empower citizens?
  • One objective of the National Information Infrastructure is to achieve
       universal access. Does the Internet achieve universal access? How do we
       design and evaluate this universal interface?
  • The Internet is moving away from being a text-only world. Now,
       multisensorial and multimodal interactions are beginning to dominate. Are
       the tools, methods, and techniques of yesterday also applicable today?
  • The Internet can be thought of as a virtual world. How can human factors
       experts influence the design of and navigation through this virtual world?
  • Hypermedia applications are a natural for the Internet. Can we or should we
       have human factors design and usability standards (e.g., as in the use of
       color or universal icons) for such applications?
  • What are the promising Internet information retrieval and storage mechanisms?
       How do these mechanisms affect everyday tasks? For example, as personal
       agents become more common, how will they affect network-based
       communications? This symposium is designed to shed light on questions like these through a variety of presentations. A brief overview of each of these presentations follows.
  • Electronic Commerce: Design of the AT&T Internet Toll-Free 800 Directory BIB --
      David Neal
    Networked Learning Communities: US West's Multimedia Show and Tell Project BIB --
      Cathleen Wharton
    Special User Populations BIB --
      Lila F. Laux
    Internet Ethics: Privacy, Fair Information Practices, and the Internet BIB --
      Beth Givens

    COMMUNICATIONS: Panel

    The Human Factors Involved in Designing an Online Reference System BIBA 218-222
      Robert M. Schumacher; Robert W. Root; Douglas R. Wieringa; Gavin S. Lew
    Throughout the last two years, we have been involved in an ambitious plan to move support documentation to an electronic document delivery system at Ameritech. The purpose of this panel is to provide a discussion of the human factors issues involved and the effort required to move from a paperbased environment to an electronic document management and delivery system. The starting state of Ameritech's documentation was similar to that of many large companies that have complex processes. The documents were written by dozens of authors over several years and varied widely in quality. Standards were loosely followed, if at all, and users were continually frustrated by their inability to find information. This unwieldy environment had countless direct and indirect impacts on customers, as well as on the bottom line.
       As we scoped the project we discovered that our challenges were legion:
  • Design a new document specification that fit the needs of the users, worked
       well on-line, exploited the capabilities of electronic information (e.g.,
       hypertext), and could be put together by our current author population;
  • Develop and implement a collaborative authoring and work flow process to
       support document creation:
  • Establish standards for writing and document rendering:
  • Design an efficient, usable user interface to the electronic document:
  • Move tens of thousands of pages of hard copy to an online system: and
  • Get the system introduced and accepted by users -- not to mention wean them
       away from paper. In this panel, we hope to stimulate discussion around a variety of these topics. We will discuss four key areas: task analysis, process changes, authoring requirements, and user interface design.
  • COMPUTER SYSTEMS: Expertise in Computer Systems [Lecture]

    Concurrent and Retrospective Verbal Protocols in Usability Testing: Is There Value Added in Collecting Both? BIBA 223-227
      Colleen Page; Mansour Rahimi
    This study compared the relative sensitivities of the concurrent and retrospective verbal protocol methods in an error analysis of human-computer interaction. Twelve subjects performed bibliographic retrieval tasks in "walk-up-and-use" usability test sessions. Each subject provided concurrent "think aloud" verbal reports throughout task performance, and then provided retrospective verbal reports while viewing their video taped performance without sound. Verbal reports that related specifically to errors were encoded as mistakes or slips, in an error classification schema which distinguished errors of intent (mistakes), from unintentional errors (slips). These data were analyzed in a 2x2 (error type x verbal protocol) repeated measures analysis of variance. In a second design, verbal protocols were encoded by statement type and analyzed in a 3x2 (statement type x verbal protocol) repeated measures analysis of variance. This study demonstrated an interaction between concurrent and retrospective methodologies and the types of error-related statements elicited. In addition, this within-subjects study supported the findings of the previous between-groups study (Bowers and Snyder, 1990). The findings support the practice of collecting concurrent verbal reports and then following up with retrospective verbal reports to collect additional information about mistakes and complex design problems.
    Expert Reviews: How Many Experts is Enough? BIBA 228-232
      Joseph Dumas; James Sorce; Robert Virzi
    We asked five usability specialists to review the user interface to a phone-based, interactive voice response system. The experts were instructed to conduct their review independently in three one-hour sessions and to record each usability problem on a Problem Description Sheet along with the elapsed time from the beginning of the hour. Each expert then spent one hour reviewing their problem sheets and making a summary list of problems. Finally, the experts spent two hours together on a conference call discussing their impressions and coming to consensus on a prioritized list of problems and solutions. The results showed that when allocating expert time, it is more effective to have a greater number of experts spend fewer hours than to use fewer experts for more hours. The individual summaries included the majority of the severe problems, but left out many less severe problems and added new problems. The group report did not surface any new problems, but described the problems as being caused by more basic design flaws and proposed solutions that focused on the conceptual model on which the design was based.
    Using the Critiquing Approach to Cope with Brittle Expert Systems BIBA 233-237
      Stephanie Guerlain
    We have conducted a series of studies aimed at understanding how to design cooperative problem-solving systems to deal with situations in which the computer is not fully competent (the "brittleness" problem). Results from an initial empirical study showed that an expert system acting as an automated assistant induced new errors in such situations, but that this did not occur when the system was designed to critique user's performance on the task. Guided by these results, a more complete critiquing system was then designed and evaluated. On cases where the computer was fully competent, outcome errors were completely eliminated (a 30-60% reduction in errors). On a case for which the system was brittle (less than fully competent), misdiagnosis rates were still reduced by 31%, giving an overall significance of p < 0.000003 across all Post-Test Cases, further supporting our initial study regarding the potential value of critiquing as an effective role for an expert system. A detailed analysis of the influence of performance further indicates the ways in which different classes of critics detect errors and influence the user's problem-solving.
    Graphic Data Model Perception BIBA 238-242
      M. E. Crosby; J. C. Nordbotten
    This paper describes an experiment in reading graphic data models which differ in graphic style. Computer science students participated in an experiment to determine if graphic style influences data model comprehension. Models with embedded graphic symbols, graphically separated symbols, or list structures were used. Protocol data, which consisted of verbal reports and eye-movements, was collected. Detailed analysis of this data provided insight into how students viewed the four types of data models. Results from this study suggest that the graphic style of the model effects the ease with which they are read and understood.

    COMPUTER SYSTEMS: Individual Differences and Strategies When Using Computers [Lecture]

    Cognitive Ability and Computing Experience Influence Interpretation of Computer Metaphors BIBA 243-247
      Douglas J. Gillan; Bruce S. Fogas; Suzanne Aberasturi; Shannon Richards
    Metaphors play a central role in human-computer interaction. Research on general metaphor interpretation has shown that different types of people interpret metaphors differently. The present experiment examined the effects of cognitive ability and computer experience on the interpretation of computer-related metaphors. Subjects completed five cognitive tests, filled out a questionnaire concerning their experience with computers, and interpreted computer metaphor terms. Identification of a term as a metaphor was related to their frequency of computer use and nonverbal cognitive ability. Concreteness of metaphor interpretations decreased with increased knowledge of programming. Abstractness of interpretations increased with frequency of computer use. The discussion focuses on metaphors in the design of user interfaces for novices and experienced users.
    The Role of Individual Differences in Determining Interaction Strategies and Performance on Computer Based Tasks BIBA 248-252
      Jennifer A. Bohan; Rafael Marshall; Deborah A. Boehm-Davis; Astrid Schmidt-Nielsen
    In completing any given task, whether it be driving or a computer task, individuals have a wide array of strategies available to them. Investigations of computer tasks have shown that individual differences of cognitive styles and abilities are related to the types of strategies individuals use to complete the task (Schmidt-Nielsen and Ackerman, 1993). Typically, those who have higher reasoning abilities use more sophisticated strategies for performing the task than those with a lower level of ability. Further, it has been demonstrated that these strategies tend to hold over a variety of tasks. For example, performance on a computer graphing task was shown to be correlated to cognitive reasoning ability. The current study extended the work of Schmidt-Nielsen and Ackerman and found that there were a wide variety of performance strategies and these strategies were correlated with reasoning ability, field dependency, and performance on the noun pair task.
    Extending the User Action Notation for Research in Individual Differences BIBA 253-257
      Derek Brock; Deborah Hix; Lynn, Jr. Dievendorf; J. Gregory Trafton
    Software user interfaces that provide users with more than one device, such as a mouse and keyboard, for interactively performing tasks, are now commonplace. Concerns about how to represent individual differences in patterns of use and acquisition of skill in such interfaces led the authors to develop modifications to the standard format of the User Action Notation (UAN) that substantially augment the notation's expressive power. These extensions allow the reader of an interface specification to make meaningful comparisons between functionally equivalent interaction techniques and task performance strategies in interfaces supporting multiple input devices. Furthermore, they offer researchers a new methodology for analyzing the behavioral aspects of user interfaces. These modifications are documented and their benefits discussed.
    The Effects of Task and Multifunction Display Characteristics on Pilot Viewport Allocation Strategy BIBA 258-262
      Karen S. Seidler; Christopher D. Wickens
    Twenty pilots searched through a 280 screen hierarchically organized data base of flight information in single task conditions, and in dual-task conditions which required concurrent monitoring of an altitude variable. Two screens were available that could either be shared between the two tasks, or fully allocated to the information access task (IAT). Search questions varied in the distance in the data base that needed to be traversed and in the extent to which they required working memory to integrate information between two screens. Subjects performed the dual task trials under either information or monitoring task emphasis, and when the monitoring task was either low or high bandwidth. The results indicated that longer single task traversals resulted from integration problems, from more distant nodes, and from nodes that shared the same top level of the hierarchy. The dual task results indicated that a measured strategic variable which facilitated performance on the IAT (the devotion of both screens to that task) was modulated as the IAT became more difficult with integration questions, as the IAT was emphasized, and as the monitoring task was at lower bandwidth. However, the result revealed that pilots failed to consider the length of the data base navigational path in their choice of single versus dual screen strategy.

    COMPUTER SYSTEMS: Real-World Issues for Computer Systems [Lecture]

    Cost-Justifying Usability Engineering: A Real-World Example BIBA 263-267
      Michael E. Cope; Kevin C. Uliano
    Human factors practitioners involved in designing graphical user interfaces (GUI) are constantly challenged with design compromises. These include the need to create an interface that contains maximum functionality and power, while striving to maintain sound human-computer interaction design principles. In a large client-server environment, subtle GUI changes to increase usability can have a significant impact on the bottom line. This paper describes a cost-benefit study comparing performance of two groups of test participants from a large wireless communication carrier. Each group performed test scenarios which isolated the effects of a single window both before and after it was redesigned. Results indicated that a single redesigned window will save an estimated $20,000 during the first year. These benefits were derived from estimating changes in end user productivity, errors, training time, and from savings obtained through decreased late design changes.
    Lessons Learned in the Development of Mobile Electronic Performance Support Systems BIBA 268-272
      Charles F. Layton; Michael J. Christodoulou; Joseph T. Jackson; Jonathan L. Turner
    There are a number of interacting constraints that affect the development of mobile electronic performance support systems (Gery, 1991). For example, users frequently want the resources of a desktop computer in a palm-sized box. Hardware technology, however, dictates that the greater the resources, the larger the device. Mobile electronic performance support systems are frequently initiated as a means to 'automate' manual processes. However, such processes must be redesigned to match the capabilities and requirements of mobile computing platforms. As a final example, the desktop conventions of "new, open, and save" used when working with documents are not necessarily the best conventions for mobile applications. This paper identifies many of the constraints involved in developing mobile computing applications and discusses them in the context of applications.
    A Comparison of Five User Interface Devices Designed for Point-of-Sale in the Retail Industry BIBA 273-277
      Karen S. Wilson; Michael Inderrieden; Steven Liu
    Although human performance on keyboards, pointing devices, and touch screens in the desktop environment has been studied and reported to the extent that the results can be used to determine productivity rates from those devices, little research has been conducted on devices used in controlled environments, like that of point-of-sale in the retail industry. While previous devices available for user interaction in this environment have been 2x20 displays and industry specific keyboards, current technology has moved the industry to implement CRTs, LCDs, full keyboards, touch screens and uniquely designed devices like the NCR DynaKey, an integrated LCD, keypad and dynamically assignable function keys. A full understanding of human performance on these devices was required to aid retailers in cost justifying their investment in them. Laboratory research was conducted to compare performance of basic point-of-sale tasks on a CRT with 56-key keyboard, 3 versions of an LCD touch screen, and the NCR DynaKey. Participants performed keying tasks, item modification tasks, a combination of item modification and scanning, and the same combination of item modification and scanning with a secondary monitoring task imposed. Time and error rates showed significant differences among the user interface devices for each of the task requirements in this research. Overall, mechanically keyed numeric entry was superior to touch screen numeric entry, mechanical keys were more advantageous with increased skill levels, and the integration of input mechanism and display as well as direct mapping between input and display enhanced performance.
    Issues in the Design of Personal Office Support Systems BIBA 278-281
      Peter J. Thomas; Stephen R. Jones; David Y. Lees; John F. Meech
    The work undertaken by office-based professionals who work closely together on information management tasks has been the object of various studies which seek to categorise and provide guidelines for the smooth performance of those tasks. However, current technology support to be found in many offices provides little in the way of integration between different information media and processes, usually relying on the workers themselves to 'adapt and survive' both in terms of 'personal work' and 'collaborative work'. This paper describes the complexities in the design of computer-based technologies to support through a detailed study of the design of a 'personal office support system' (POS) currently being undertaken.

    COMPUTER SYSTEMS: Human Factors Issues and the Internet I [Symposium]

    Human Factors Issues and the Internet I BIB --
      Cathleen S. Wharton; Ray E. Eberts
    Overview of the Internet: Users and Providers BIB --
      Michelle Owens
    Video and Graphics: When is Less Media More Message? BIB --
      Joel S. Angiolillo
    Human Factors Design Information via the Internet: Graphical Symbols and Icons BIB --
      Fred Brigham
    Neural Net Agents for Intelligent Searching BIB --
      Ray E. Eberts

    COMPUTER SYSTEMS: Human-Computer Interaction [Lecture]

    Factors Affecting Remote Positioning Performance BIBA 282-286
      Shang H. Hsu; Chien C. Huang
    The purpose of this study was to investigate the effects of target width, movement direction, movement amplitude, and remote distance on remote positioning performance. Movement time and movement distance ratio were taken as measures of remote positioning performance. It was found that the effects of target width, movement amplitude, and movement direction on the two measures were significant. The effect of remote distance was significant only for movement distance ratio. The magnitude of the effect of target width on movement time was larger than that of movement amplitude; a modification of Fitts' Law was thus proposed. Moreover, there was an interactive effect between target width and movement direction -- i.e., movement direction had an effect only when the target width was small. Among the eight movement directions, upward vertical movement was the best for remote positioning. The results shed some light onto the design of remote control user interface.
    Contextual Linking: Supporting Weak Models of Navigation in Information Exploration BIB --
      Sarah Zuberec; Mark H. Chignell
    A Comparison of Graphical User Interface Widgets for Various Tasks BIBA 287-291
      Todd J. Johnsgard; Stanley R. Page; Robert D. Wilson; Ronald J. Zeno
    The purpose of the present study was to compare user performance, accuracy and preference while using standard user interface controls or "widgets" to complete specific types of tasks. Radio buttons were significantly faster, accurate, and preferred than any other widget for the mutually exclusive selection tasks. For the non-mutually exclusive selection tasks, check boxes were significantly faster and preferred. These widgets were superior due to the fact that all possible options were initially visible. As the number of options increased, the time to complete each task also increased. A practitioner's table for selecting effective widgets for specific types of tasks is provided. Further implications for user interface design and research are discussed.
    Perceived Workload between the Keybowl and the QWERTY Keyboard BIBA 292-296
      Peter McAlindon; Gene C. Lee
    The Keybowl alphanumeric input device was designed and developed to totally eliminate finger movement and drastically reduce wrist motion. Typing without finger movement requires a typist to adapt to a new method of key activation. This new method requires new mental, physical, and temporal demands, associated with new levels of performance, effort, and frustration. Together these requirements are measured to produce an overall measure of workload. Keybowl workload requirements are somewhat different than QWERTY keyboard workload requirements. With the significant reduction of finger and wrist motion comes concern over how much workload is expected in re-learning to type with the Keybowl. Typing workload was analyzed via the NASA Task Load Index. Typing workload analyses were performed to determine how the two groups of subjects (Keybowl and QWERTY) compared in terms of overall workload.

    CONSUMER PRODUCTS: Design Guidelines and Measurement Tools in Product Design [Lecture]

    Measurement and Analysis of Pressure Distribution on the Bed BIBA 297-300
      Se Jin Park; Min Cheol Whang; Chang Bum Kim
    A new measurement system for body pressure on a bed was developed in this study. The thin film pressure sensor (FSR: Force Sensing Resistor) of an elastomer-type was used to prevent the distortion of contact pressure. The pressure distribution was measured by FSR and displayed on the monitor by color-coded contour patterns. The body pressure distribution and the objective data for four beds with different firmness were observed for possible correlation with the subjective evaluation. Ninety-eight occupants subjectively evaluated five beds for a short-term flying session about 1 hour. The pattern of the pressure distribution was analyzed to correlate approximately with the difference between comfortable and uncomfortable bed. The verification test on the recommended bed was performed by other twenty subjects through one week.
    Adding and Subtracting Percentiles -- How Bad Can It Be? BIBA 301-305
      John G. Kreifeldt; Keoun Nah
    When performing anthropometric analysis or design, it frequently happens that some particular anthropometric value is not tabulated although it would appear to be derivable by adding or subtracting two relevant and tabulated dimensions. Because percentile values are usually required, there is the temptation to add or subtract the relevant percentile values of the two tabulated dimensions. In some cases, this will produce minimal or no error between the actual percentile value and the result of adding/subtracting the tabulated values, while in other cases, the resulting percentile will be very seriously in error. The magnitude of the errors depends on the percentiles, correlation coefficient and ratio of the standard deviations of the two variates.
       This paper details the combinations of these three factors for which adding/subtracting two identical percentile values produces acceptable as well as grossly misleading results. Several tables, charts and equations are provided to aid in this common problem. The results may be particularly useful when only the ratio of standard deviations may be known or approximated rather than their individual values. In general, subtracting percentiles leads to greater errors than adding them.
    Single-Line Display Menu BIBA 306-310
      Sung H. Han; Jiyoung Kwahk
    Many electronic consumer products use a single line display which is capable of presenting a limited number of characters at a time. Although many design guidelines have been proposed, they are applicable only to the menus on ordinary CRT displays. This study examined the effects of four different variables: menu structure, user experience, navigation aid, and number of target items on designing the menu on a single line display. Four dependent measures, speed, accuracy, efficiency, and user preference of a target search task, were collected. The results showed that the 82 structure turned out to be an optimal menu structure for single-line display menus. The navigation aid improved the search performance of the inexperienced. Interestingly, multiple target search tasks recorded a better performance than single target search tasks. Based on the results, design implications were discussed.

    CONSUMER PRODUCTS: Children: Design Perspectives for a Small World [Lecture]

    An Evaluation of the Fun Factor for the Microsoft EasyBall Mouse BIBA 311-315
      Edie Adams; Elizabeth B.-N. Sanders
    Microsoft was interested in measuring the "fun" value of a new input device, the Microsoft EasyBall mouse (designed specifically for two to six year olds), relative to three other input devices available in the marketplace. An evaluation was conducted as a means of ensuring that the ergonomic considerations incorporated into the design of a new child's pointing device addressed the emotional needs, as well as the physical and cognitive needs, of the intended users. A research and test methodology was established to look at this issue from multiple simultaneous perspectives, using both behavioral and verbal measures. Forty four children (half boys and half girls, mixed across the age levels) and their parents were included in the study. The children varied in their level of expertise with computer and/or video games. The same basic procedure was used for all the children, with adaptations made to accommodate the attention spans and skill levels of the youngest.
       The children indicated through a variety of converging measures that the Microsoft EasyBall mouse was their input device of choice. The patterns of behavior varied across the age groups, but the choices of the children were clearly in favor of the Microsoft EasyBall mouse. The parents were quite accurate at predicting which input device their child would pick.
       A detailed examination of the videotaped sessions provided cues that caused a rethinking of the initial question "How fun is the Microsoft EasyBall mouse relative to the other input devices?". The fun factor may have been more accurately described as a "feel good" factor. Results are discussed in terms of implications for expanding the typical physical and cognitive-based ergonomics analyses for consumer products to include emotional considerations as well.
    Knowledge of Compatibility Rules among Children 2 to 13 Years of Age BIBA 316-320
      L. P. A. Steenbekkers
    Lack of data, suitable to be used by designers of daily-life products, was a reason to start a national study on physical, psychomotor and behavioral characteristics of children between 2 and 13 years of age in the Netherlands. Data were gathered on several variables, one of them being technical comprehension. A measuring method was developed to measure knowledge of some commonly used compatibility rules. The results from almost 1000 children showed that age differences can be found at the ages between 5 and 9. For some of the youngest children the test appeared to be just a funny game, while for the older children the test might have been too childish. Influence was found for type of control. Direction of movement and orientation of the control had little influence on the results.
    Adult Notions of Adults' and Children's Perceptions of Consumer Product Risk BIBA 321-325
      Amy J. Hammond
    An experiment was performed to examine adults' perceptions of other adults' and children's perceptions of risk. The differences in how adults assess risk to themselves, to other adults, and to children based on their own perceptions and on the perceptions they believe the "others" will hold for themselves were explored. Results found that adult subjects do judge risk as greater for others than for themselves, particularly for young children. A "superiority bias" was found, such that products were assessed to be more risky for others than others would assess for themselves. Implications of a discrepancy between the perceptions adults assign to children and the perceptions of children themselves is discussed.

    CONSUMER PRODUCTS: Culture, Perception, and People in Product Design [Lecture]

    Living Room Culture -- An Anthropological Study of Television Usage Behaviors BIBA 326-330
      Robert J. Logan; Sheila Augaitis; Robert H. Miller; Keith Wehmeyer
    Traditionally, research at Thomson has been conducted in the laboratory. This study, however, took place in users' homes. This work investigated the television (TV) viewing behaviors of nine households over an 10-week period and was designed to provide a better understanding of how and why people watch TV within the home. Applying a combination of methods from the fields of human factors and anthropology, viewing behaviors were observed via computer-logged TV commands, interviews, questionnaires, photographs, and other methods. Analysis of the resulting data will cover three major areas: 1) tabulation of computer-logged TV usage behaviors, 2) tabulation and interpretation of personal observations, and 3) comparison of the computer-logged data with the personal observations. This analysis will result in a more complete list of user requirements that includes both behavioral and emotional usability issues. Such requirements will be applied to the design of future consumer electronics.
    Participatory Design Shapes Future of Telephone Handsets BIBA 331-335
      William R., Jr. Dolan; Michael E. Wiklund; Robert J. Logan; Sheila Augaitis
    Telephone handset design has evolved for decades along with advancements in technology and manufacturing methods. Today, a handset could be reduced to a slim rod incorporating a miniaturized earpiece and microphone. However, most handsets look like the venerable K-type handset, such as those found today on many household and business telephones. Should future handsets continue to follow suit, or are there significant opportunities for improvement? Initially, we conducted five focus groups to answer this question. To begin each session, we photographed consumers holding handsets to assess gripping styles. Then, consumers rank ordered six conventionally designed handsets and six progressively designed handsets according to several ergonomic and emotional attributes. They also critiqued the handset designs according to personal preference and built clay models of their ideal handset. Based on this input, our team of human factors and industrial design specialists designed 6 new concepts, then obtained quantitative and qualitative feedback by conducting thirty focus groups in three metropolitan areas. This follow-on research, that included free association, sample handset assessment and, paired comparison and ranking exercises, identified significant opportunities to improve handset comfort, appearance, and emotional appeal. A Kruskall-Wallace H-test showed few significant differences in consumer preferences among 18 sample handsets. Our results indicate that users prefer a handset that can be shouldered, looks modern, feels good in the hand, and conforms to the face. We found that users are receptive to design innovation, but only if there is an ergonomic payoff. We include a discussion of detailed design recommendations in the last two sections.
    Perceived Differences in Running and Walking Shoes BIBA 336-340
      Ravindra S. Goonetilleke; Michael T. Cann
    Designers rely heavily on the past sales history of a particular shoe when attempting to make decisions regarding shoe characteristics of future shoes. Cushioning devices made of air, "super" gases, energy return rubber, and gel's have become popular. However, the question that needs to be asked is whether these devices are truly functional or whether they are primarily of aesthetic value. Shoe qualities such as cushioning, comfort, stability, shock absorption, and energy return play an important role during athletic activity. It is also known that the above mentioned characteristics have significant interactions with each other. Hence it is important to know the relevance of these interactions when designing shoes for a particular activity. The primary goal of this study was to investigate the interaction and relevance of shoe properties during running and walking. Four specially fabricated shoes were used in the study. The results indicate the following: Heel cushioning and shock absorption play an important role in the overall cushioning of a midsole. Runners perceive shoe-heel cushioning somewhat differently from those who use shoes for walking. Heel cushioning during running seems to be influenced by shock absorption, stability and possibly rebound. Heel cushioning during walking seems to be influenced by shock absorption and possibly rebound. Hence a good running shoe can in most cases satisfy the biomechanical needs during walking.
    ColorTool: An Information Tool for Cross-Cultural Design BIBA 341-345
      Surya Vanka; David Klein
    Color meanings vary dramatically across cultures. Sometimes globally marketed products fail, either commercially or in use, because designers were unaware of culture specific meanings associated with the colors they selected. Designers generally tend to base color decisions on aesthetic reasons, and on anecdotal knowledge of cultures. This is primarily because of the lack of truly useful information tools that can assist them in making informed cross cultural color choices. ColorTool is a computer based tool that designers can use to learn about culture-specific color dialects, to search for colors associated with specified meanings, or to check the cultural appropriateness of aesthetic color choices. This paper describes the development, use, and evaluation of ColorTool. Further, it discusses the potential for network tools that could involve cultural experts and even users in the color selection process.

    CONSUMER PRODUCTS: Product Information: Risk, Culture, and Warnings [Lecture]

    Adding Consequence Information to Product Instructions: Changes in Hazard Perceptions BIBA 346-350
      Curt C. Braun; Stephanie A. Glusker; Ronda S. Holt; N. Clayton Silver
    Product instructions represent one possible medium through which product hazard and safety information can be conveyed. Recent research has demonstrated that the likelihood of precautionary behavior increases when such behaviors are explicitly described within the product-use instructions. Although precautionary information has been provided within the instructions, some users are unable to translate this information into action. Moreover, the inclusion of explicit actions within product-use instructions has not been shown to influence perceptions of product related hazards. The present effort evaluated the utility of adding consequence information to product instructions. A sample of 193 participants evaluated the likelihood that they would be injured while using two different products displaying instructions that outlined only the actions to be performed, actions followed by consequences, consequences followed by actions, and actions with the product warning repeated within the instructions. The data revealed that instructions outlining the consequences before the actions yielded the highest likelihood of injury ratings. Measures of instruction complexity, however, revealed no significant differences between instruction sets. The data, in conjunction with previous findings, suggest that product-use instructions represent a viable means of conveying product hazards.
    Hazard Level Perceptions of Current and Proposed Warning Sign and Label Panels BIBA 351-355
      Michael J. Kalsher; Michael S. Wogalter; Blair M. Brewster; Marilyn E. Spunar
    A growing number of studies have investigated factors associated with various measures of warning effectiveness, including noticeability, comprehension, and most importantly, compliance. Some research has begun to examine the components comprising signs and labels (e.g., signal words, color). However, there has been virtually no research on people's perceptions of sign/label configurations that are currently found on warnings. The present study evaluates the warning styles that are specified in ANSI (1991) Z535.2 and Z535.4 standards, as well as a set of proposed styles. The results confirmed several specifications in current standards (e.g., the signal word DANGER was perceived as more hazardous than the other currently-specified signal words), whereas other specifications were not fully confirmed (e.g., the WARNING configuration as indicating higher hazard than the CAUTION configuration). Some newly developed warning styles (e.g., using the signal word DEADLY and a skull icon) show promise for better signaling highly hazardous conditions.
    Decision Making Processes in Risky and Nonrisky Consumer Product Selection BIBA 356-360
      Cassie B. Barlow; Amy J. Hammond
    Decision making in the domain of risk has traditionally been studied by examining gambling behavior. The control of outcome probabilities obtained in these paradigms masks much of the subjective nature of everyday risk decision choices, such as product selection and information search patterns. A study was undertaken to examine decision making processes in Risky and NonRisky consumer product decision tasks. Subjects completed two Information Display Board (IDB) decision tasks, one selecting a Risky consumer product (oral contraceptive) and one selecting a NonRisky consumer product (toothpaste). The results supported the hypotheses that consumers view the decisions to purchase risky and non-risky products differently and use different patterns of information acquisition in making decisions in the selection of these products. Few anticipated differences were found between Experienced and NonExperienced users of oral contraceptives in information acquisition. Implications for health care professionals providing oral contraceptive information to patients are discussed.

    CONSUMER PRODUCTS: Ergonomic Design of Input Devices [Lecture]

    User Preferences between Keyboards While Performing "Real" Work: A Comparison of "Alternative" and Standard Keyboards BIBA 361-365
      Donald L. Morelli; Peter W. Johnson; Cheryl R. Reddell; Patricia Lau
    The proliferation of varying computer keyboard designs may pose problems to those who specify, purchase and ultimately use such devices. Are any of them "best" for my work? Will actual users derive any benefit from them? To assist in addressing such issues, we explored an approach to determining if any of three "alternative" keyboards provided a benefit to employees by increasing user comfort. A total of 34 employees participated in this study, each using an "alternative" keyboard for one week at a time while performing their actual work. After using each keyboard, including their standard "101" keyboard, subjects completed a questionnaire of seven psychophysical measures relating to the comfort and use of the keyboard. Questionnaire responses were tabulated and a Repeated Measures Analysis of Variance conducted. Statistically significant differences were found among and between the four keyboards on four of the seven psychophysical measures. Overall results showed little differences in user assessments between three of the keyboards, with the fourth keyboard assessed less favorably when significant differences were found. The results suggest that user assessments can produce significant results between keyboards, and that no one "best" keyboard exists for any given set of tasks and group of users.
    Wrist Postures While Typing on a Standard and Split Keyboard BIBA 366-368
      M. Honan; E. Serina; R. Tal; D. Rempel
    Fifty experienced typists participated in a laboratory based repeated measures study with two factors: keyboard height (three) and keyboard configuration (three). The work surface heights tested were 63, 67 and 71 cm. The three keyboard configurations tested were: standard (Apple Extended), alternative keyboard A (Microsoft Natural Keyboard) and alternative keyboard B (equivalent to Natural Keyboard with Leveler extended). Wrist and forearm posture data was acquired using electronic goniometers during 10 minutes of typing at each keyboard/height level. Across all heights tested, wrist extension, wrist ulnar deviation, and forearm pronation were statistically significantly closer to neutral when using alternative keyboard B than when using the standard keyboard.
    Design Criteria of an Ergonomic Mouse Computer Input Device BIBA 369-373
      Richard Pekelney; Robin Chu
    The rapid growth of graphical user interfaces on personal computers has led to the mouse input device playing a prominent and central role in the control of computer applications. As their use increases, mouse design and comfort issues are becoming more and more critical. This report describes the ergonomic design criteria and resulting product attributes of a commercially successful mouse computer input device. Although well-founded ergonomic principles were incorporated into the design criteria, very little ergonomic research has been published on the design of mice. There is a need for additional research on the ergonomics computer mouse input devices.
    Manipulation of Pushbuttons and Round Rotary Controls BIBA 374-378
      H. Kanis; L. W. van Hees
    This study focuses on the manipulation of pushbuttons and round rotary controls on consumer products in practice. It shows that these controls are operated in many different ways. The majority of the observed manipulations is applied both by physically impaired and non-impaired users. Variation occurs in both groups. However, variation which occurs in one group only, almost always occurs in the impaired group. People experiencing operational difficulties used hardly any new types of manipulation compared to smooth operation - that is when no difficulty is experienced in reaching a control, gripping it and exerting the required force. These findings suggest that operational difficulties function as incentives urging users concerned to resort to abilities which otherwise they would not have to draw on, rather than as constraints. From a design point of view the findings indicate that people facing difficulties in the use of everyday products would benefit from multi-operable controls, that is with a great degree of freedom for manipulation.

    EDUCATORS' PROFESSIONAL: Panel

    Preparing for the Human Factors/Ergonomics Job Market BIBA 379-383
      Ronald G. Shapiro; Megan L. Brown; Maxwell Fogleman; Joseph H. Goldberg; Richard E. Granda; Joseph P., II Hale; Elizabeth B.-N. Sanders
    The panel is designed to help an individual decide on a specialization in human factors/ergonomics and to prepare to enter the human factors job market. Panelists were selected to represent a cross-section of the field, and are from the following sectors: the electronics industry (Megan Brown), loss prevention research (Max Fogleman), academia (Joe Goldberg), the computer industry (Dick Granda), the government (Joe Hale), and consulting (Liz Sanders).

    EDUCATORS' PROFESSIONAL: Tools and Techniques for Teaching Human Factors and Ergonomics [Lecture]

    An Undergraduate Human Factors Workbook BIBA 384-388
      Jacqueline Reynolds Mozrall; Jasper E. Shealy
    The Industrial and Manufacturing Engineering (IME) Department at Rochester Institute of Technology (RIT) requires undergraduate students to take two courses in human factors, with both courses possessing a laboratory requirement. In an effort to consolidate support materials for the undergraduate human factors courses, a supplemental workbook was developed. The workbook provides both the students and instructors with a varied selection of laboratory exercises and homework problems which are directly relevant to the material being covered in the lectures and laboratories. The workbook includes specific guidelines for the required laboratory format, a selection of laboratory exercises and homework problems, and appendices which include supplemental material related to the laboratory exercises and a large set of human factors references. The workbook has been very beneficial for instructors, for it provides an organized set of information which directly supports both the lecture and laboratory material. Questionnaire data obtained from students identified good features of the workbook, as well as areas which needed improvement.
    Introducing Human-Centered Design Early in the Engineering Curriculum BIBA 389-393
      Joel S. Greenstein
    This paper focuses on the development and implementation of a cross-disciplinary, project-driven course on human-centered design. The sophomore-level course is required of all students in the industrial engineering major. The course prerequisites are a part of the college-wide freshman engineering curriculum, enabling students in other engineering majors to take the course as well. The primary objective of this course is to introduce the product development process and human-centered methodologies for designing engineering systems into the engineering curriculum. Additional objectives are to:
  • Let the students experience the product development process through a
       semester-long, real-world design project.
  • Prepare students to work with other specialists in the kind of
       cross-functional design teams employed in engineering practice.
  • Educate students to focus early and continually on the customers and users of
       their products.
  • Use a variety of writing and speaking activities to achieve active
       participation in the educational process, team building, and a class
       environment dedicated to professional success.
  • Enhance retention of engineering students by emphasizing collaborative
       learning and the product development process early in the curriculum.
  • Performing the System Design Process: An Intelligent Way to Learn BIBA 394-398
      Russell J. Sojourner; Wesley A. Olson; Gary L. Serfoss
    Structuring the ideal human factors curriculum has received considerable interest in recent years. A common theme stresses the need for hands-on learning. The United States Air Force Academy recently developed a human factors design course that emphasized critical thinking skills through interactive, collaborative techniques. Steps critical to the system design process were taught to the students and were subsequently performed by student design teams. The teams then submitted competitive proposals for a workstation being built as part of an actual dormitory renovation project. A "winning" design was selected at the culmination of the course, and was later implemented by construction contractors. The design effort received universal praise by Academy management, architects, and civil engineering personnel. Educational success was measured by standardized student critique data which rated the course significantly higher than composite scores from all Academy offerings. Collaborative hands-on design appears to have been a successful method of teaching critical human factors principles.
    Using Simulations in Teaching Human Factors: Bridging the Gap between the Academic World and the World of Work BIBA 399-403
      William F. Moroney; Joyce A. Cameron
    The nature of the world of work in which human factors professionals practice requires both knowledge and skill. Students of human factors need educational experiences which demand more than the acquisition of information in order to be prepared for this world. To meet this need for a broader educational experience, we incorporated three simulations into the design of a graduate course in Human Factors in Systems Development.
       The decision to use these three simulations required not only a restructuring of the course content, but also a reconsideration of instructional procedures. Fortunately, in the field of education there are "models of teaching" which can assist individuals who want to use simulations in teaching by providing guidance in shaping curriculum, in designing instructional materials, and in guiding instruction.
       The purpose of this paper is fourfold: (1) to describe the curriculum and the simulations used, (2) to indicate the type of educational objectives associated with each simulation, (3) to share a model of teaching which is intended specifically for use in conjunction with the use of classroom simulations, and (4) to relate some ideas about other types of simulations that we have begun to incorporate into other courses.
       It is our belief that the use of simulations can enhance the learning of both content and skills. More important, it can provide students with opportunities to experience the consequences of their individual and group efforts at problem-solving and decision making, and it can help bridge the gap between the academic experience and the world of work.

    EDUCATORS' PROFESSIONAL: Panel

    Undergraduate Human Factors Education: Could it be Utilized and Marketed Better? BIBA 404-408
      Nancy J. Stone; Mark W. Smolensky; William F. Moroney; Daryle Jean Gardner-Bonneau; Earl S. Stein
    This panel session addresses the concern that undergraduate education in human factors has not been utilized or marketed effectively. Specifically, the panelists propose that an undergraduate course or program is a means by which to inform people about the human factors area, to prepare undergraduate students for employment with a bachelors degree, and to enhance the working student's skills needed in the workplace. Additionally, the use of undergraduate education as a proactive means to introduce and attract individuals to the field of human factors is presented.

    ENVIRONMENTAL DESIGN: Office Workstation Design: Micro to Macro [Lecture]

    An Estimation of Lumbar Height and Depth for the Design of Seating BIBA 409-411
      William R. Dowell
    The horizontal and vertical position of the apex of the lumbar curve of 773 seated persons were measured. The position of the lumbar landmark is given. Three common seated anthropometric measurements were also taken: popliteal height, buttock-popliteal length, and elbow rest height. The three common measurements are compared with data from an existing anthropometric data base.
    Analysis and Design Recommendations for Workstations: A Case Study in an Insurance Company BIBA 412-416
      William J. Cohen; Craig A. James; Alvaro D. Taveira; Ben-Tzion Karsh; Julie Scholz; Michael J. Smith
    A case study approach was used to determine the effects of task demands, customer needs, and organizational environment on the recommendations for ergonomic redesign in a large pension and insurance organization. The organization was planning a major renovation of workstations and requested assistance with design and implementation. Three job positions were studied using semi-structured interviews, job observations, and measurements of workstations and the office environment. It was found that most work surfaces and chairs were inadequate for VDT tasks, reception counters presented problems for both the employees and claimants, and the use of shared VDTs on a swivel base resulted in eyestrain and poor postures. In addition, there was inadequate storage space and poor housekeeping for all three jobs, as well as lighting and noise problems throughout the office environment. Recommendations were made for new workstations, with pilot testing to be conducted before full-scale implementation. Although existing workstations were inadequate, it was found that task demands were of greatest concern to the employees.
    Enhancing User Control of VDT Work Environments: Training as the Vehicle BIBA 417-421
      Michelle M. Robertson; Marie Robinson
    An intervention strategy to minimize negative health effects from VDT operations is to incorporate a systems perspective and apply systems analysis methodologies. Two systems components, user control and training programs, and their relationship within the VDT environment, are examined in this paper. Two exemplary case studies of organizations that have systematically designed, implemented, evaluated and incorporated VDT ergonomic training programs in conjunction with user control are presented.
    Effects of Office Layout and Sit-Stand Adjustable Furniture: A Field Study BIBA 422-426
      Rajendra D. Paul
    In a controlled field study, twelve office employees with computer-intensive jobs were monitored during the redesign of their work environment. Before office redesign, they worked in closed offices with four walls and sitting height, non-adjustable workstations. Then they worked in more open offices with three walls and sit-stand adjustable VDT workstations. The effects of this office redesign were evaluated three months post-occupancy. During the three months, employees worked standing for two hours every day. The results suggest that change in the office layout, i.e. open versus closed, increased the interaction and communication between employees. However, it significantly decreased employees' perceived privacy, and increased the amount of visual and noise distractions. In the offices with sit-stand adjustable furniture, subjects felt more energetic and less tired by the end of the workday.

    ENVIRONMENTAL DESIGN: Panel

    Concepts for Designing a Building BIBA 427-429
      Daniel McCrobie; Marie Robinson; Michael J. O'Neill; Stephen C. Boelter; Alan Hedge; Simonetta A. Rodriguez
    This panel was designed by Marie Robinson of Pacific Bell, the Program Chair for the Environmental Design Technical Group. Marie wanted to put together several speakers who have unique views and different backgrounds on how buildings should be designed for the user. The resulting panel should be an interesting mix of ideas, all with a focus on the user.

    FORENSICS PROFESSIONAL: Forensics Research in Consumer Preferences [Lecture]

    On Making Legal Documents Understandable: Objective and Subjective Measures BIBA 430-434
      Julie E. Howe; Michael S. Wogalter
    Citizens are often asked to sign a variety of legal documents such as contracts, monetary agreements, and consent forms, but the adequacy of how well informed average citizens become when they sign such documents is unclear. A recent survey indicated that respondents signed a variety of legal documents that they did not fully read or understand (Howe and Wogalter, 1994). Participants in that survey also identified characteristics of legal documents that hinder their understanding and offered suggestions for improving understandability. In the current study, these characteristics and suggestions were used to create two different consent forms: a conventional "legalistic" consent form and an improved consent form. These were compared with each other and with a third, one-line, consent form (a control). Understandability was assessed using an objective comprehension test and measures of participants' subjective perceptions of understandability. Consistent with the hypotheses, objective comprehension and participant's subjective understanding was significantly enhanced by the improved form relative to the conventional form. Comprehension in the control condition was significantly lower than either of the other two consent forms conditions. In addition, even though comprehension was poor with the conventional legalistic consent form, all but one person receiving that form signed it, agreeing to participate in an activity that was described as having some risk of explosion and burn injury (jump starting a dead battery with booster cables). There was also a tendency for more participants with the improved form than the conventional form to take advantage of a stated option of participating in a less risky activity (a card sorting task). The importance of understanding legal documents as well as the implications for additional work in this domain are discussed.
    Allocation of Responsibility for Product Safety BIBA 435-439
      Kenneth R., Sr. Laughery; David R. Lovvoll; Michael S. Wogalter
    Three studies were carried out to explore how people allocate responsibility for safety during product use. In Study 1 29 consumer products were named and subjects apportioned safety responsibility to the manufacturer, the retailer, the user, and a potentially relevant organization not in the stream of commerce (e.g., FDA, CPSC, Underwriters Laboratories). The mean percent responsibility allocated to these four alternatives was 43%, 9%, 27% and 21% respectively. A significant interaction indicated that the allocation varied across products. In Study 2 safety responsibility for the same products was allocated to the manufacturer, retailer and user, but the "outside" organization was omited. The mean percent allocated was 51%, 20% and 30% respectively. In this study, additional questions assessed various perceptions of the products and the subject's familiarity with the products. The results indicated that responsibility allocation was a function of perception of product hazardousness; the more hazardous a product is perceived to be, the more responsibility is allocated to the user. Study 3 investigated some of the attributes of high hazard products which are associated with various allocations of product safety. For high hazard products with open and obvious risks (chain saws, cutting torches), more responsibility was allocated to consumers as opposed to manufacturers. On the other hand, for those high hazard products with "hidden" risks (pesticides, antifreeze), manufacturers were typically allocated a much higher degree of responsibility.
    Signal Words: Perceived Carefulness by the Developmentally Disabled BIBA 440-444
      N. Clayton Silver; Kenneth Tubilleja; Rozana Ferrante
    The current standards recommend using signal words such as DANGER, WARNING, and CAUTION to connote varying degrees of hazard. Most research concerning the connoted strength of signal words has used college students as participants. One at-risk population that has not been adequately studied, however, includes people with developmental disabilities. The purpose of the present research was to determine whether people with developmental disabilities understand these signal words. Moreover, connotation comparisons would be made concerning other populations sampled from previous research. sample of 46 people with developmental disabilities rated 43 potential signal words on how careful they would be after seeing each term. In general, the ratings of the developmentally disabled were consistent with populations sampled from previous research. The words that were frequently left blank by the developmentally disabled were used less frequently in the English language and were higher in grade level. The forensic implications and relevance concerning hazard communication are discussed.

    FORENSICS PROFESSIONAL: Panel

    Professional Conduct for Ergonomic Experts in Forensics -- II BIBA 445-447
      Leighton L. Smith; Thomas A. Dingus; Hal W. Hendrick; Waldemar Karwowski; Dieter W. Jahns; Richard J. Hornick
    This panel intends to further the exploitation of the subject matter that was addressed in a panel held at the 1994 annual meeting (Smith et al., 1994). The panelists for that panel were: Mel Rudov, Thomas Dingus, Jake Pauls, and Gary Staffo. These individuals presented their views on the panel subject ranging from a synopsis of the history of a code of conduct in the professional ergonomics discipline (Mel Rudov), to a discussion on the merits and motivations for establishing a code of conduct (Tom Dingus), to a perspective on the ramifications of specialization (Jake Pauls), to a perspective from the professional safety community (Gary Staffo).
       The purpose of this panel (iteration "II") is to further examine the foundation and aspects of a code of conduct for professionals in the specific practice of ergonomic forensics. Both the view of individual professionals who practice full-time ergonomic forensics work and also who have practiced extensively will contribute to this panel. The goal of this panel is to attempt to achieve a balanced viewpoint of professional.

    GENERAL SESSIONS: Debate

    "Smart Automation Enhances Safety": A Motion for Debate BIBA 448-449
      Harold P. Van Cott; Earl Weiner; Christopher Wickens; Harold Blackman; Thomas Sheridan
    The Debate Resolution:
       Attempting to structure the benefits and hazards of rapidly evolving technologies within an envelope that defines what is safe, feasible and economically viable, is difficult. While experts may not have a neat way to do this in hand, they can sometimes piece together experience and wisdom in interesting ways and occasionally strike a spark that illuminates the darkness. Toward this end four authorities in human performance and automaton. will debate the following proposition, stated in the form of a resolution
       "Be it Resolved: That Smart Automation Enhances Safety."

    GENERAL SESSIONS: Panel

    Future Directions in Cognitive Engineering and Naturalistic Decision Making BIBA 450-453
      Mica R. Endsley; Gary Klein; David D. Woods; Philip J. Smith; Stephen J. Selcon
    Cognitive Engineering and Naturalistic Decision Making are presented as two related fields of endeavor that seek to understand how people process information and perform within complex systems and to develop ways of applying this knowledge within the design and training process. This panel presents an overview of the current state of the art in this research domain and charts paths for needed developments in the field in the near future.

    GENERAL SESSIONS: Process Investigation, Fault and Error Diagnosis [Lecture]

    Patterns of Errors Shown by Experienced Navy Combat Information Center Teams BIBA 454-458
      Susan G. Hutchins; Daniel P. Westra
    The Tactical Decision Making Under Stress program is being conducted to apply recent developments in decision theory and human-system interaction technology to the design of a decision support system for enhancing tactical decision making under highly complex conditions. Topics to be discussed include: (1) a description of the difficult tasks identified for analysis; (2) the general methodological approach; (3) development of the performance measures and issues related to their development; (4) discussion of the modification and extension of the TapRoot Incident Investigation System; and (5) discussion of the types of errors made by decision makers and interpretations for the cause of these errors based in the cognitive psychology literature.
    Diagnosis of Multiple Faults in Systems: Effects of Fault Difficulty, Expectancy, and Prior Exposure BIBA 459-463
      Penelope M. Sanderson; Dal Vernon C. Reising; Marc J. Augustiniak
    It has often been noted that today's human operators of complex industrial systems must occasionally deal with multiple component failures, but that they are trained instead to think in terms of single faults. This can lead to the minor inconvenience of simply taking longer to troubleshoot, or to the major hazards of a fundamental misunderstanding of system state. In two studies we examined these influences on subjects' ability to diagnose a multiple fault in a simulated electronic circuit: (1) objective multiple fault difficulty, (2) prior practice with multiple faults, and (3) expectancy or mental set for multiple faults. Previous research had confounded the latter two variables. Experiment 1 showed that the difficulty of multiple faults varied as our model predicted, but that the difficulty of certain faults interacted with verbalization. Experiment 2 showed that both prior practice and expectancy influence how effectively subjects deal with a difficult multiple fault, but not quite as expected. We conclude that the ability to diagnose multiple faults is multiply determined, depending on degree of practice, mental set, and the difficulty of the multiple fault itself. These results will help us define the requirements for decision support tools and they have also led us to perform investigations in the field, as reported in Reising and Sanderson (1995).
    Mapping the Domain of Electronic Repair Shops: A Field Study in Fault Diagnosis BIBA 464-468
      Dal Vernon C. Reising; Penelope M. Sanderson
    Recent experimental research has indicated that different multiple faults impose differing levels of objective and subjective difficulty on human troubleshooters. Technological advances suggest that systems are becoming more complex and integrated, in which case multiple components will fail. Operators will have to be able to deal with these more complex failures. In this paper we report field work conducted in order to build and substantiate a model of the factors influencing fault diagnosis in the field. By conducting field observations and by constructing concept maps, we investigated how expert troubleshooters handle the difficulty associated with diagnosing multiple faults. The troubleshooters were expert electronic technicians in departmental repair shops on a large university campus. The end product of the research is a model of fault diagnosis that is grounded in field data. Our results suggest that diagnostic difficulty arises from several factors: (1) organizational structure, (2) technicians' strategies for fault diagnosis, and (3) equipment design. The field observations and concept maps indicate that technicians approach the diagnostic task with standard, ritualistic methods that they have developed over years of experience. They generally go through two phases of troubleshooting: (1) the problem definition phase and (2) what we call the At-the-Equipment-TroubleShooting (AETS) phase. Technicians also reason about multiple failures in series, considering one simple explanation at a time. Our principal conclusion is that in real-world settings the three previously mentioned factors have evolved to avoid situations in which technicians must engage in prolonged functional reasoning. These findings will be used (1) to develop further the model of fault diagnosis, and (2) to guide future experimental investigations studying the influences of fault diagnosis.
    Decision Making in Dynamic Environments: Fixation Errors and Their Causes BIBA 469-473
      Y. Xiao; C. F. Mackenzie
    One of the goals of naturalistic studies of human decision making is to reveal the cognitive loads or task difficulties imposed on the decision maker in real work environments. Fixation errors or cognitive lockups have been reported as a unique type of performance failure in dynamic work environments, and are thus particularly valuable to the understanding of the challenges and difficulties confronting practitioners in dynamic environments. In this paper, we present the analysis of fixation errors during real-life trauma patient resuscitation. The analysis elicits two factors, both rooted in the inherent complexity of the domain, that contributed to the occurrence of fixation errors: unreliable monitoring devices and delayed feedback. The former induces the behavior of preferring confirmatory information, partly for redundancy checks. The latter may create a false sense of system stability and divert attention away from the correct diagnosis.

    GENERAL SESSIONS: Panel

    Naturalistic Decision Making: A Domain-Integrated Overview BIB 474-477
      Kathleen L. Mosier; Judith Orasanu; David M. Gaba; Emilie M. Roth; George N. Brander

    GENERAL SESSIONS: Potpourri [Lecture]

    Human Factors -- The Early Years BIBA 478-480
      David Meister
    One way to examine the progress of the Human Factors discipline is to perform a content analysis of the programs of the Society's early annual meetings. The period covered is 1959-1972, after which proceedings were published. The results of the analysis shows that interest in some research topics ebbs and flows, whereas other interests remain relatively stable.
    Designing User Models in a Virtual CAVE Environment BIBA 481-485
      Alenka Brown-VanHoozer; Randy Hudson; Nihar Gokhale
    In this paper, the results of a first study into the use of virtual reality for human factor studies and design of simple and complex models of control systems, components, and processes are described. The objective was to design a model in a virtual environment that would reflect more characteristics of the user's mental model of a system and fewer of the designer's. The technology of a CAVE virtual environment and the methodology of Neuro Linguistic Programming were employed in this study.
    Usability and Learning in Educational Virtual Realities BIBA 486-490
      Marilyn C. Salzman; Chris Dede; R. Bowen Loftin
    Designing ScienceSpace, a series of virtual realities for teaching difficult science concepts and skills, has implications for designing sensorily immersive educational virtual realities. Through the design and evaluation of the worlds in ScienceSpace we are gaining insights into the general utility of sensorial immersion, as well as virtual reality's potential and limitations for enhancing learning. This paper focuses on the learner-centered design and evaluation of NewtonWorld, one of the virtual worlds in ScienceSpace. NewtonWorld is a sensorily immersive virtual learning environment in which students can challenge their intuitions about Newton's laws and the conservation of energy and momentum through game-like inquiry activities. We discuss how usability and learning issues have shaped the design and refinement of NewtonWorld. Additionally, we discuss implications of our work for designing sensorily immersive virtual reality interfaces that are usable and facilitate learning.
    Human Performance Analysis of Industrial Radiography Radiation Exposure Events BIBA 491-495
      Wendy J. Reece; Susan G. Hill
    A set of radiation overexposure event reports were reviewed as part of a program to examine human performance in industrial radiography for the U.S. Nuclear Regulatory Commission. Incident records for a seven year period were retrieved from an event database. Ninety-five exposure events were initially categorized and sorted for further analysis. Descriptive models were applied to a subset of severe overexposure events. Modeling included: (1) operational sequence tables to outline the key human actions and interactions with equipment, (2) human reliability event trees, (3) an application of an information processing failures model, and (4) an extrapolated use of the error influences and effects diagram. Results of the modeling analyses provided insights into the industrial radiography task and suggested areas for further action and study to decrease overexposures.

    GENERAL SESSIONS: Ecological Interface, Design, and Analysis Issues [Lecture]

    Ecological Interface Design and Fault Management Performance: Long-Term Effects BIBA 496-500
      Klaus Christoffersen; Christopher N. Hunter; Kim J. Vicente
    This paper presents a six-month longitudinal study of the effects of ecological interface design (EID) on fault management performance. The research was conducted in the context of DURESS II, a real-time, interactive thermal-hydraulic process control simulation that was designed to be representative of industrial systems. Subjects' performance on two interfaces was compared, one based on the principles of EID and another based on a more traditional piping and instrumentation diagram (P&ID) format. Subjects were required to perform several control tasks, including startup, tuning, shutdown, and fault management on both routine and non-routine faults. At the end of the experiment, subjects used the interface that the other group had been using to control the system. The results indicate that there are substantial individual differences in performance, but that overall, the EID interface led to faster fault detection, more accurate fault diagnosis, and faster fault compensation.
    Ecological Design for a Network Scheduling Interface BIBA 501-505
      Carl Edlund; Sam Hume; Michael Lewis
    A motivation in the design of Ecological Interfaces for process control is to augment the strengths of the human operator with the strengths of the automation in the computer system. This is especially important when building interfaces for managing the use of Wide Area Networks (WANs) in enterprise computing. This domain requires network operators to be able to control the allocation of resources and to monitor the occurrence of structural and functional failures. The relationship between the network architecture, infrastructure, traffic characteristics, and pricing scheme is dynamic and highly inter-related. A "Tetris-like", bin-packing interface is designed based on principles drawn from an ecological user model and a situation theoretic representation of the problem space and the user's task. The effectiveness of this display is based on a number of ecological features whose design is automatically generated through the determination and selection of the interface context.
    Emergency (911) Dispatcher Decision Making: Ecological Display Development BIBA 506-510
      R. Jay Shively
    Emergency dispatchers must make complex life or death decisions under extreme time pressure. Using Ecological Task Analysis (ETA), a technique normally applied to aerospace human factors problems, a new display was designed that would better assist their decision making task. The major design constraints were identified to be the beat number and priority of incidents, available units, and the spatial relationship of the those units to the incident. Using these and other less formal factors, a GUI interface was designed and an evaluation was conducted at the Richmond, CA police dispatch center. The results suggest that the GUI display may reduce training times and increase situational awareness.
    MacSHAPA: Software Support for Exploratory Sequential Data Analysis BIBA 511-515
      Penelope M. Sanderson
    This paper outlines the need for better conceptual and methodological tools for performing observational data analysis in support of cognitive engineering research and practice and presents a tool, MacSHAPA, that has been designed to support such work. MacSHAPA is particularly suited for cognitive engineering studies of complex real-world decisionmaking. MacSHAPA lets users (1) enter or import data into a spreadsheet-like viewing medium, (2) annotate, manipulate, and visualize data in various ways, (3) carry out statistical analyses of various kinds, and (4) export data and results to other applications. MacSHAPA controls video devices, capturing timecode and inserting it into the database, and using timestamps in the database to locate events of interest on videotape. MacSHAPA's statistical routines include content and duration analysis, transition analysis (with some Markov statistics), lag sequential analysis, cycles reports, and some kinds of sequential pattern matching. The paper concludes with several examples of how MacSHAPA has been used to obtain useful results from observational data collected in laboratory and field settings.

    GENERAL SESSIONS: Panel

    State of the Art and Current Activities in Human Modelling Technology BIBA 516-518
      Narinder Nayar; Norm Badler; Robert Carrier; Don Chaffin; Yili Liu; Jerry Duncan; Cynthia Nelson; Louise Obergefell; Barry Smith; John Roebuck
    Computer-based human modelling technology has been in existence since the early 1980s. However, most earlier human models were either hard to use or lacked appealing graphics. With rapid developments in 3D computer graphics, it is now possible to interactively manipulate and analyze human models in a virtual environment. This coupled with growing user interest has spurred rapid development and use of human modelling and simulation.

    GENERAL SESSIONS: Cognitive Task Analysis: What Is It? Why Do It? [Symposium]

    Cognitive Task Analysis: What Is It? Why Do It? BIBA 519
      Kim J. Vicente; Emilie M. Roth; Gary A. Klein; Sallie E. Gordon
    Cognitive task analysis (CTA) is increasingly being used to effectively address a wide variety of human factors problems. However, different researchers are using significantly different methods. In many cases, a particular method is used solely by its originators. Therefore, there are significant issues that must be worked through before CTA becomes a widely accepted and easily transferable human factors tool. The objectives of this symposium are to: bring CTA to the attention of a wider audience; develop a better understanding of the differences and similarities between different CTA methods; and demonstrate the practical advantages of CTA.
    Using Cognitive Task Analysis to Define Human Interface Requirements for First-of-a-Kind Systems BIBA 520-524
      Emilie M. Roth; Randall J. Mumaw
    Cognitive task analysis (CTA) methods have grown out of the need to explicitly consider cognitive processing requirements of complex tasks. A number of approaches to CTA have been developed that vary in goals, the tools they bring to bear, and their data requirements. We present a particular CTA technique that we are utilizing in the design of new person-machine interfaces for first-of-a-kind advanced process control plants. The methodology has its roots in the formal analytic goal-means decomposition method pioneered by Rasmussen (1986). It contrasts with other approaches in that it is intended: (1) for design of first-of-a-kind systems for which there are no close existing analogues precluding the use of CTA techniques that rely on empirical analysis of expert performance; (2) to define person-machine interface requirements to support operator problem-solving and decision-making in unanticipated situations; and (3) to be a pragmatic, codified, tool that can be used reliably by person-machine interface designers.
    Cognitive Task Analysis Using Complementary Elicitation Methods BIBA 525-529
      Sallie E. Gordon
    Cognitive task analysis is accomplished using a wide variety of methodologies, and we have previously argued that different methods will tend to elicit qualitatively different types of knowledge and skills. Because of this, many practitioners use complementary methods for a given project. We have developed such a complementary package of knowledge elicitation techniques, along with a specific representational method, which together are termed conceptual graph analysis. Conceptual graph analysis is domain-independent and can be used to evaluate complex cognitive tasks or subtasks. It relies on the successive use of document analysis, interviews, task observation, and induction based on review of task performance. The information from these elicitation techniques is represented as a set of interrelated conceptual graphs, but can be represented in other formats also. There are several issues relevant to cognitive task analysis that are currently being faced, including when to perform this type of analysis, and what methods to use. One answer is to perform cognitive task analysis when the task has an inherently high degree of cognitive complexity.
    The Value Added by Cognitive Task Analysis BIBA 530-533
      Gary Klein
    Cognitive Task Analysis (CTA) attempts to describe how people perform tasks: the cues and patterns they use, their inferences and strategies, mental models, and other related topics. It differs from behavioral task analyses that seek to enumerate the steps that must be followed without examining the expertise needed to perform critical steps. Therefore, CTA provides a more in-depth picture, which complements the broader and more comprehensive behavioral task analysis.
       A CTA usually consists of five steps: Preparation, Knowledge Elicitation, Data Analysis, Knowledge Representation, and Application. The applications of CTA can take a number of forms, such as training, system design, personnel selection, and market research.
    Task Analysis, Cognitive Task Analysis, Cognitive Work Analysis: What's the Difference? BIBA 534-537
      Kim J. Vicente
    The term cognitive task analysis (CTA) has been appearing in the human factors literature with increasing frequency. Others have used the term cognitive work analysis (CWA). Is there a difference? Do either of these methods differ from traditional task analysis (TA)? If so, what advantages can CTA/CWA provide human factors engineers? To address these issues, the history of work analysis methods and the evolution of work are reviewed. Work method analyses of the 19th century were suited to manual labor. As job demands progressed beyond the physical, traditional TA was introduced to provide a broader perspective. CTA has since been introduced to increase the emphasis on cognitive task demands. However, CTA, like TA, is incapable of dealing with unanticipated task demands. CWA has been introduced to deal with complex systems whose demands include unanticipated events. The initial evidence available indicates that CWA can be applied to industry-scale problems, leading to innovative designs.

    GENERAL SESSIONS: Alternative Format

    President's Forum: Using the Real World as a Metaphor in User Interface Design BIB --
      Deborah A. Boehm-Davis

    GENERAL SESSIONS: Panel

    Human Factors in Agile Manufacturing BIBA 538-542
      Chris Forsythe; Waldemar Karwowski; Marietta Baba; Eric N. Wiebe; Saadi Lahlou; M. Rodema Ashby
    The contributions of human factors to agile manufacturing are as varied as the numerous human components that constitute an industrial enterprise. As a framework for discussing some specific examples relevant to the elements of agility identified above, human factors contributions are categorized as follows: (1.) development of business practices; (2.) design of enabling technologies and (3.) management of the introduction and fielding of new technologies and business practices. The panel session will provide an introduction to these contributions, and an accounting of past and ongoing work.

    INDUSTRIAL ERGONOMICS: Hand and Wrist Analysis [Lecture]

    The Effects of Gender, Wrist, and Forearm Position on Maximum Isometric Power Grasp Force, Wrist Force, and Their Interactions BIBA 543-547
      Kerith K. Zellers; M. Susan Hallbeck
    The interaction of power grasp force and wrist force has not been previously examined. This research not only examined the effect of task (wrist force in flexion and extension with and without simultaneous power grasp force), but the effects of gender, wrist position, and forearm position on maximal static exertions. Gender, wrist position, and task were found to significantly affect both power grasp and wrist forces. Females averaged 59.5% of male power grasp force and 51% of male wrist force. Power grasp force was significantly greater in neutral and extended wrist positions than flexed wrist positions while a neutral wrist position generated significantly greater wrist forces than both extended and flexed wrist positions. Due to synergistic conflicts, grasp force during simultaneous wrist extension force was significantly less than grasp force during simultaneous wrist flexion force (60%) and grasp force only tasks (58%). Wrist extension forces were found to exceed flexion forces which contrasts with previous research studies. In addition, wrist forces during simultaneous grasp force did not differ from wrist forces with fingers relaxed.
    A Mechanical Model of Hand Force in Power Hand Tool Operation BIBA 548-552
      Robert G. Radwin; Seoungyeon Oh; Frank J. Fronzcak
    A three-dimensional static equilibrium mechanical model of power hand tool operation was developed and used for comparing hand force associated with use of nutrunners having similar operating parameters (i.e. torque and feed force) but different physical parameters (i.e. shape, size, and mass distribution). The model used a Cartesian coordinate system relative to the orientation of the handle grasped in the hand using a power grip. Several important relationships between tool parameters and required hand force were revealed. Resultant hand force associated with different torque and feed force requirements were compared between four pistol grip nutrunners, and between pistol grip and right angle tools used for the same operation. Accessory handles and counterbalancers are also included in the model. Further development and validation of this model will be useful to power hand tool designers and tool engineers.
    Analysis of Hand Tool Grips BIBA 553-557
      Myung Hwan Yun; Andris Freivalds
    An efficient measurement and evaluation system for hand tool tasks can provide a practical solution to the problem of designing and evaluating manual tool tasks in the workplace. Such a prototype system, termed the data glove, was developed by overlaying twelve Force Sensitive Resistors on an posture-measuring glove (Cyberglove, Virtual Technologies, 1992) with eighteen joint angle sensors. To validate the data glove, hand posture and grip force was measured on sixteen different cylindrical grip tasks for six subjects. A factor analysis of the grip force distributions on the hand indicated that three major areas of force concentration occurred: 1) an area of high force levels termed the 'active' area, 2) an area of intermediate force levels termed the 'support' area, and 3) an area of low force levels termed the 'inactive' area. The different grips were also classified and ranked for levels of radian/ulnar deviation torques and flexion/extension torques, and then combined with the force information to yield a pattern of grip degradation with increasing levels of grip stress. A validation experiment comparing the data glove force output with the muscle surface EMG measurement yielded a significant, high correlation between the two measures.
    Practical Application of a Biaxial Goniometer to the Wrist Joint BIBA 558-562
      Bryan Buchholz; Helen Wellman
    The objectives of this study were: 1) to determine errors in wrist angle measurements from a commercially-available biaxial electrogoniometer and 2) to develop a calibration routine in order to correct for these errors. Goniometric measurements were simultaneously collected with true angular data using a fixture that allowed wrist movement in one plane while restricting motion in the orthogonal plane. These data were collected in two sets of trials: 1) flexion/extension with radial/ulnar deviation restricted and 2) radial/ulnar deviation with flexion/extension restricted. During these trials, discrete 30 degree increments of forearm rotation were studied. The results showed the expected cross talk and zero drift errors during forearm rotation. The application of mathematical equations that describe the effect of goniometer twist during forearm rotation resulted in significant error reduction for most trials. The calibration technique employs both a slope and a displacement transformation to improve the accuracy of angular data. The calibration technique may be used on data collected in the field if forearm rotation is measured simultaneously with the goniometer data.

    INDUSTRIAL ERGONOMICS: Seated Workstations [Lecture]

    Effect of Sit-Stand Schedule on Spinal Shrinkage in VDT Operators BIBAK 563-567
      Rajendra D. Paul; Martin G. Helander
    A controlled field study was conducted to measure spinal shrinkage in office employees with sit-stand type workstations. Thirteen office employees, ten healthy and three with spinal disorders participated in the study. Using a stadiometer, changes in stature were measured at 8 a.m., 12 p.m., 1 p.m. and 5 p.m. From 12 p.m. to 1 p.m., all subjects sat for 40 minutes and walked for 20 minutes. Out of the ten healthy employees, six were instructed to stand for 30 minutes four times during the day. The remaining four subjects stood eight times 15 minutes each. Office workers who stood in 30 minute sessions experienced significantly less shrinkage than those who stood in 15 minute sessions. Office workers with spinal disorders also stood eight times 15 minutes each. They incurred a greater variability in the shrinkage pattern.
    Keywords: Spinal shrinkage, VDT work, Sit-stand workstations
    Foot Swelling in VDT Operators with Sitting and Sit-Stand Workstations BIBA 568-572
      Rajendra D. Paul
    In a controlled field study, effect of sit-stand workstations on foot swelling during the course of a workday was monitored in visual display terminal (VDT) operators. Six VDT operators first worked in offices furnished with nonadjustable sitting workstations. Then they worked in offices furnished with sit-stand adjustable furniture for six weeks. In the later setting, they stood for 15 minutes every hour. In both settings, the foot swelling was measured at 8 a.m., 12 p.m., 1 p.m. and 5 p.m. using a foot volumeter. Between 12 p.m. and 1 p.m., subjects walked for 20 minutes and sat for 40 minutes. The results showed that the average right foot swelling in offices with sit-stand adjustable furniture was significantly less than that in offices with nonadjustable furniture, 12.3 ml (1.1 percent) compared to 21 ml (1.8 percent). These results suggest that activity promoted using sit-stand workstations benefits sedentary office workers.
    An Ergonomic Approach to Modifying Microscope Design for Increased Comfort: A Case Study BIBA 573-577
      Tamara M. James
    This paper describes the approach used and the results of selected measures obtained from an ergonomic analysis of microscopes and associated workstations in a medical laboratory. The configuration of current microscopes and workstations in this lab caused a great deal of neck, back, forearm, and wrist discomfort or pain for workers who use microscopes to screen microslides for cancer and infectious conditions an average of 6 - 8 hours per day. Modifications to workstations and microscopes were developed and are being introduced within the Cytopathology Screening Laboratory at Duke University Medical Center. Prior to developing modifications to the microscopes and workstations, surveys of body part discomfort and anthropometric data were used to identify areas of concern. It is believed that users will be more comfortable and injury and error rates will decrease as a result of making modifications that allow users to utilize neutral body postures while using microscopes.
    Office Ergonomics Training Effectiveness BIBA 578-581
      Gary Niekerk
    This paper focuses on the effectiveness of an office ergonomics training program at a large semiconductor company, as measured through a widely distributed questionnaire. The questionnaire was sent to 2,000 randomly selected office employees located at five domestic locations. Of the 2,000 employees selected for the study, 1,000 had received office ergonomics training and 1,000 had not received office ergonomics training (control group). The sample size was equally distributed among sites to block for potential variations between site populations. The overall response rate for the survey was 36%. Survey participants responded to questions on knowledge and skills acquired through training; levels of pain and discomfort; and behavioral change. For all survey questions, except those relating to pain and discomfort, there was a statistically significant (F probability <.0005) difference between the trained group and the control group.

    INDUSTRIAL ERGONOMICS: Upper Extremity [Lecture]

    The Effects of Latex Examination Gloves on Hand Function: A Pilot Study BIBA 582-585
      Benny J. Moore; Sudheer R. Solipuram; Michael W. Riley
    Over the last decade the use of latex examination gloves by dental professionals has increased significantly. The proliferation in latex glove use is primarily due to recommendations and guidelines established by both the Centers for Disease Control and the Occupational Safety and Health Administration. Because a significant number of dental professionals are wearing latex examination gloves, it is important to understand the limitations and restrictions associated with wearing these gloves. This study investigated the effects of hand condition on three-jaw chuck pinch strength, power grip strength and manual dexterity. Hand condition consisted of three levels: (1) bare hand, (2) hand with a normal sized latex examination glove and (3) hand with a tight fitting latex examination glove. The results of the study indicated that latex examination gloves do not have an effect on three-jaw chuck pinch strength or power grip strength. However the study suggested that ill-fitting latex examination gloves significantly reduce manual dexterity.
    Ergonomic Glove: Design and Evaluation BIBA 586-590
      A. Muralidhar; R. R. Bishu; M. S. Hallbeck
    A new design for gloves was developed based on the principle of selective protection where protective material is introduced in varying levels over different parts of the glove in order to provide protection where it is most needed and at the same time preserve the desirable dexterity and strength capabilities of the barehand, optimizing the trade-off between protection and performance. The pattern for selective protection was arrived at based on existing research, and two pairs of gloves incorporating different levels of protection have been prototyped and are currently being tested using a battery of performance tests and an Algometer test for pressure sensitivity. A battery of tests was developed to evaluate a new glove design which used the principle of selective levels of protection over different parts of the hand in order to maximize protection and minimize loss of dexterity. The test battery comprised of four dexterity tasks and a maximal voluntary grip strength task. The battery assessed the performance of 5 hand conditions, barehand, single glove (one layer), double glove (two layers), and two prototype gloves, one with one layer of protection (contour glove) and the other with four layers of protection over selected parts of the hand (laminar glove). The evaluation compared the performance of the prototype gloves developed with respect to the performance with the double layer glove and the single layer glove. The results indicated that the performance of the prototype gloves was comparable, and that the performance times for the double glove and the two prototype gloves tested were not significantly different. For the test of grip strength, the two prototype gloves tested enabled better performance than the double glove. The assembly task performance for the prototype II (laminar glove) was significantly lower than that of the other glove types tested.
    Reporting of Cumulative Trauma Disorders of the Upper Extremities May be Leveling Off in the United States BIBA 591-594
      George Erich Brogmus
    Since the early 1980's reporting of cumulative trauma disorders of the upper extremities (CTDUEs) has been increasing. The past few years have seen increasing attention given to these disorders. More recently, the premise that CTDUEs should be a top priority based on the magnitude of workers' compensation insurance claims and OSHA cases has been challenged. This paper provides data indicating that the reporting of CTDUEs in the U.S. may soon level off and the rate of increase of the number of CTDUEs as a percent of all cases reported in the U.S. has already significantly declined. Data from both the Bureau of Labor Statistics and Liberty Mutual Group workers' compensation claims indicate that even though the number of CTDUEs as a percent of all cases reported has been increasing over the past ten years, the rate of increase has declined steadily since 1991. If this trend continues, CTDUE reporting will level off in 1995. Possible reasons for these trends are briefly discussed.
    Quantitative Biomechanical Analysis of Wrist Motion in Bone-Trimming Jobs in the Red-Meat Packing Industry BIBA 595-599
      John F. Monroe; Richard W. Marklin
    This study was motivated by the serious impact that cumulative trauma disorders (CTDs) of the upper extremities have on industrial workers and on industry itself. To date, no quantitative data has been gathered on the kinematics of hand and wrist motion required in bone-trimming jobs in the red-meat packing industry. No information is known about what type and how much wrist motion is currently being used in bone-trimming jobs in the red-meat packing industry, or how much these motions increase the risk of occupational CTDs. The research conducted addressed this current research void and established a preliminary database of wrist and hand kinematics for a bone-trimming job in the red-meat packing industry. This kinematic database could augment the red-meat industry's efforts to reduce the severity and cost of CTDs. Ergonomics practitioners in the red-meat industry could use the kinematic methods employed in this research to assess the CTD risk of current and redesigned jobs that require repetitious, hand-intensive work.
       The study examined the wrist motions used by nine red-meat packing workers who performed bone-trimming jobs. These jobs are highly repetitive and hand-intensive. Quantitative measures of the kinematic parameters of wrist motions performed on the bone-trimming line were measured using goniometry. The wrist motion measures consisted of the following statistics in the radial/ulnar, flexion/extension, and pronation/supination planes: 1). mean, minimum, and maximum of wrist angle position, 2). mean, minimum, and maximum of angular velocity, and 3). mean, minimum, and maximum of angular acceleration.
       The kinematic data were compared to manufacturing industry's preliminary wrist motion benchmarks. These benchmarks were the means and variances of nine dependent variables of position, velocity, and acceleration from industrial workers who performed hand-intensive, repetitive work in jobs that were of low and high risk of hand/wrist CTDS (Marras and Schoenmarklin, 1993). Results of this comparison show that numerous wrist motion variables in both the left and right hands of bone-trimming workers are in the high-risk category. This quantitative analysis provides biomechanical support for the high incidence of CTDs in the bone-trimming line of the plant that was investigated.

    INDUSTRIAL ERGONOMICS: Lifting Biomechanics [Lecture]

    A Biomechanical Assessment of Axial Twisting Exertions BIBA 600-604
      Kevin P. Granata; William S. Marras
    Axial twisting of the torso has been identified as a significant risk factor for occupationally related low-back disorders. The purpose of this investigation was to examine the influence of dynamic twisting parameters upon spinal load. Measured trunk moments and muscle activities were employed in a biomechanical model to determine loads on the lumbar spine. Spinal loads were examined as a function of dynamic torsional exertions under various conditions of force, velocity, position, and direction. Results demonstrate significant flexion-extension and lateral moments were generated during the twisting exertions. Muscle coactivity was significantly greater than equivalent levels measured during sagittal lifting exertions. Relative spinal compression during dynamic twisting exertions was twice that of static exertions. Spine loading also varied as a function of whether the trunk was twisted to the left or right, and the direction of applied torsion, i.e. clockwise versus counter-clockwise. The results may help explain, biomechanically, why epidemiological findings have repeatedly identified twisting as a risk factor for low-back disorder.
    The Effect of a Commercially Available Support Belt on Torso Posture, Lift Strength, and Spinal Compression BIBA 605-609
      Brian Randall Sherman; Jeffrey C. Woldstad
    The purpose of this research was to measure changes in torso posture when a commercially available abdominal support belt was worn. In addition, this study investigated whether the belt affected static lift strength and predicted spinal compression of the L3/L4 intervertebral disc.
       Eight males and eight females were asked to perform maximal static exertions on handles attached to a steel rig. Lifts were performed from symmetric and asymmetric positions at different heights while the support belt was worn and not worn.
       It was found that static lift strength and torso posture, with the exception of axial twist, were not significantly affected by belt use. Axial twist for low asymmetric exertions was significantly larger when the belt was worn as compared to when the belt was not worn. Predicted spinal compression was significantly lower when the belt was worn (2738 N) as compared to the nonbelt conditions (3087 N).
    Selective Activation of the External Obliques during Twisting BIBA 610-614
      Dan Kelaher; Gary Mirka; Ann Baker; Angela Harrison; Joe Davis
    This study investigated selective activation of different regions of the external obliques. Six subjects performed sub-maximal isometric axial twisting exertions (20%, 40%, 60% of MVC) while assuming six different postures defined by three levels of axial rotation (-20°, 0°, 20°) and two levels of sagittal flexion (0° and 20°). As the subjects performed these isometric exertions, the integrated EMG activity was sampled at five different locations on both the right and the left external oblique muscles. The results showed significant differences in the activation of different regions of each of the external obliques. The implications of selective activation of these muscles on spine biomechanics are discussed.
    Predicted Muscular Activity for Varying Inputs to Optimization-Based Biomechanical Trunk Models BIBA 615-619
      Mark L. McMulkin
    The Minimum Intensity Compression (MIC) model developed by Bean, Chaffin, and Schultz (1988) and the Sum of the Cubed Intensities (SCI) model developed by Crowninshield and Brand (1981) have been used to predict trunk muscle forces during external loads. The models require muscle geometries (moment arms, lines of action, and cross-sectional areas) as inputs. This paper reports on a computer simulation conducted to evaluate the changes in trunk muscle forces predicted by the MIC and SCI models with changes in inputs. Two muscle geometries were used for a 10-muscle set one reported by Han, Ahn, Goel, Takeuchi, and McGowan (1992) and a second formed by a compilation of several studies. The results indicate that regions of muscle activity and magnitude vary greatly between the models and associated inputs. Muscle EMG data indicating active and inactive loading conditions reported by Lavender, Tsuang, Hafezi, Andersson, Chaffin, and Hughes (1992) are significantly predicted by the model combinations for some right side muscles.

    INDUSTRIAL ERGONOMICS: Keyboard Development and Analysis [Lecture]

    Activity of Index Finger Muscles during Typing BIBA 620-624
      Carolyn M. Sommerich; William S. Marras; Mohamad Parnianpour
    An electromyographic investigation was conducted of finger and wrist muscle activity during typing. Examination of the data revealed substantial activity of the extrinsic extensor, a muscle which is ignored in many existing biomechanical finger models. This paper describes activity of the extensor muscle during typing, in absolute terms and relative to activity of the extrinsic flexors. Amplitude probability distribution analyses demonstrated that static extensor activity exceeded 5% MVC for all subjects. Two subjects exhibited pronounced patterns of coactivity in the extrinsic extensor and flexor muscles. Biomechanical modeling efforts demonstrated similar force contributions from the extrinsic extensors and flexors. Based on these results, neglect of finger extensor activity would result in underestimation of finger joint loading.
    Wrist Posture during Computer Mouse Usage BIBA 625-629
      Elizabeth A. Damann; Karl H. E. Kroemer
    In this experiment, we investigated the effects that mouse pad surface height and wrist support had on wrist posture. In a pointing task, 16 subjects moved a mouse-controlled cursor clockwise or counterclockwise around three fixed targets, which varied by size and distance depending on task condition. Wrist extension, flexion, radial deviation, and ulnar deviation data were collected via a wrist monitor attached to the right hand and forearm.
       The presence of a wrist support decreased wrist extension and radial deviation, and increased wrist flexion. Higher pad surface height resulted in increased flexion and ulnar deviation, and decreased extension and radial deviation. A comparison of the conditions which were at the same pad height, but differed due to the presence or absence of wrist support, revealed that wrist extension was reduced by the presence of a wrist support at all but the highest height.
    Healthy Keyboarding: Effects of Wrist Rests, Keyboard Trays, and a Preset Tiltdown System on Wrist Posture, Seated Posture, and Musculoskeletal Discomfort BIBA 630-634
      Alan Hedge; Daniel McCrobie; Bruce Land; Singe Morimoto; Simonetta Rodriguez
    A field experiment is described in which wrist posture, seated posture measured using the RULA method, and musculoskeletal discomfort, recorded by self-report questionnaires, was assessed for 38 office workers while they typed the same text. A pretest survey was conducted to assess the effects of typing with a conventional keyboard on a desk or on an articulating keyboard tray, and with or without wrist rests. Following this, workers were randomly allocated to either a control group (n=15), for whom nothing changed, or a test group (n=23) that used their existing keyboard in a preset tiltdown (PT) system. After some 3 weeks of using the PT system a posttest survey was conducted for both groups. Results showed no significant changes in wrist posture, seated posture, or reports of musculoskeletal discomfort for the control group. Significant improvements in wrist posture, seated posture, and upper body musculoskeletal discomfort were found for workers using the PT system. Workers expressed a strong preference for using a keyboard with the PT system.
    A Comparative Analysis of Typing Errors between the Keybowl and the QWERTY Keyboard BIBA 635-639
      Peter McAlindon; Kay Stanney; N. Clayton Silver
    The Keybowl keyboard is the first known keyboard alternative to totally eliminate finger movement and drastically reduce wrist motion. With the significant reduction of finger and wrist motion comes concern over where the repetitive forces are being transferred. In typing with the Keybowl, biomechanical requirements are somewhat different than those in using a QWERTY keyboard. One way to help determine how well typists perform biomechanically is through keystroke error analysis. Typing performances were therefore analyzed via keystroke errors to determine if Keybowl "key" activation was different from QWERTY key activation. An error analysis for each character, hand, and gender was performed. This analysis has built a foundation for comparing two very different types of upper extremity motions and how they might affect a proficient QWERTY typist's performance in typing with the Keybowl.

    INDUSTRIAL ERGONOMICS: Lifting and Carrying [Lecture]

    Maximum Acceptable Load for Lifting and Carrying in Two-Person Teams BIBA 640-644
      Marilyn A. Sharp; Valerie J. Rice; Bradley C. Nindl; Robert P. Mello
    The purpose of this study was to determine and verify the maximum acceptable load for lifting and carrying (MAL-L&C) in single- and mixed-gender two-person teams. Participants lifted and carried a box 7.2 meters and placed it on a 132 cm high shelf, at rates of 1 x/min and 4 x/min. All male teams lifted and carried significantly (p<.05) more weight than all female teams or mixed-gender teams, and mixed-gender teams carried more than all female teams (p>.05). Our findings demonstrate that 1) individuals working alone or in teams can accurately estimate their ability to lift and carry loads for an hour, and that 2) when working in pairs, team MAL-L&C are approximately equal to the sum of their individual MAL-L&C. Percentile norms for MAL-L&CS are provided for male, female, and mixed gender teams.
    Prediction of Two-Person Team Lifting Capacity BIBA 645-649
      Valerie J. Rice; Marilyn A. Sharp; Bradley C. Nindl; Randall K. Bills
    Predictive models for team lifting capacity are important for task and equipment design, as well as worker selection and placement. The purpose of this study was to develop a prediction equation for single gender and mixed gender two-person team lifting from the floor to knuckle height. Men (n=23) and women (n=17) were combined into teams of two men (n=26), two women (n=24), and one man with one woman (n=25). Independent variables included incremental dynamic lift, 38 cm upright pull, dead lift, fat free mass, and body mass. A least squares linear regression was used. In addition, an equation was developed from deadlift strengths only. The lightest individual deadlift and the sum of the individual deadlifts were the best predictors of team lifting capacity (R² = 0.90, SEE = 16). The results indicate that two-person team lifts to knuckle height are determined by the weaker team member.
    The Effects of Lifting Frequency on the Dynamics of Lifting BIBA 650-654
      Gary A. Mirka; Daniel P. Kelaher
    The goal of this study was to quantify the effects of different lifting frequencies (3, 6 and 9 lifts/minute) at different lifting heights (30 and 60 cm) on the kinematics of the lumbar region. Each of these lifting tasks was performed for twenty minutes. The time dependent traces of the both the mean and standard deviation of sagittal acceleration showed subject dependent trends over time. Averaged across time, the results of this study reveal that there is a non-linear increase in the sagittal acceleration with greater frequency of lifting.
    Stability Limits in Extreme Postures: Effects of Load Positioning and Foot Placement BIBA 655-659
      M. A. Holbein; D. B. Chaffin
    Although injuries related to postural stability are prevalent, ergonomic job analyses have traditionally not addressed stability issues. In this research, functional stability limits are quantified for persons standing in extreme postures under various external load and foot positioning conditions. Six subjects were tested while standing unladen and while holding a 5.2 kg load. The foot positions, or bases of support (BOS), were varied in width of the stance and sagittal separation of the feet. They were asked to lean and displace their center of gravity (COG) as far as possible in eight directions to the sides and front of the body. Stability measures based on these COG displacements were calculated. All controlled variables significantly affected the stability measures. When standing unladen, subjects extended their COG to within 99% of their BOS limit. Movement was much more restricted when leaning while handling a load (89%), especially holding it with one hand on the shoulder (84%). On average, increased separation of the feet in a particular direction resulted in larger COG displacements in that direction. The results are discussed relative to their effects on balance and stability modeling.

    INDUSTRIAL ERGONOMICS: Ergonomic Implementation [Lecture]

    Ergonomics Applied to Product and Process Design Achieves Immediate, Measurable Cost Savings BIBA 660-663
      Andrew J. Marcotte; Sheri Marvin; Troy Lagemann
    Two case studies are used to demonstrate how one company achieved immediate improvements to employee safety and manufacturing profitability by integrating ergonomics assessment and design practices into current product and process improvement efforts. One case study shows how a product design change resulted in a reduction of hand trimming tasks on a molded plastic part, and a cost savings of $0.11 per part. The other case study shows how integration of process performance criteria into an ergonomics assessment method identified a process change which, when implemented, resulted in the elimination of the most stressful materials handling task on the assembly line and a cost savings of $0.10 per part.
    Ergonomic Evaluation of the General Purpose Workstation on a Space Mission BIBA 664-668
      Mihriban Whitmore; Frances E. Mount
    The Human Factors and Ergonomics Laboratory (HFEL) at the Johnson Space Center conducted an ergonomic evaluation of the General Purpose Workstation (GPWS), a glovebox-type workstation flown on one of the Spacelab Life Sciences missions. The HFEL study consisted of: (1) Crew evaluations via pre-flight, in-flight questionnaire and structured post-flight interview, and (2) Video analysis. Findings indicate that the workstation design was acceptable for performing dissection tasks. The crew reported that the task distribution between operators was completely acceptable. Based on the video analysis and the crew comments, the glove interface was found to be critical for crew comfort. A follow-up evaluation is planned for an upcoming mission to evaluate a materials science glovebox and the design impact on posture. Additional microgravity evaluations are planned to obtain objective data on postural changes while working at different gloveboxes.
    The Design and Installation of an Ergonomic Workstation for a Packing Operation: A Case Study BIBA 669-672
      Kelly Eckbreth McVey
    A team of engineers, shop employees, and the plant Ergonomist at a major telecommunications manufacturing plant set-out to design a new workstation dedicated to end-of-line packaging of finished work. The strengths and weaknesses of existing workbenches on the manufacturing floor were examined and the needs of their particular process listed. Based on this examination, alternative bench designs were studied and a final prototype specified. Modular, flexible, and adjustable worksurfaces and components, as well as process changes, were incorporated to optimize the packing operation. The bench purchased and installed for this operation has been well received by the operators and has allowed them to work comfortably with telling productivity.
    Estimating the Anthropometry of International Populations Using the Scaling Ratio Method BIBA 673-677
      Marc Resnick
    Appropriate anthropometric data is a critical ingredient to good ergonomic design. For many populations, the available anthropometric data is severely limited; often just weight and stature is available. This study measured twenty key dimensions of the Colombian population to establish preliminary anthropometric measures in anticipation of a wider study, and evaluated the ability of the Scaling Ratio method to predict these data from anthropometric data of other populations. Results suggested that prediction errors are generally small when the reference population is similar in age, size, and ethnicity to the target population. However, the errors of some dimensions will be sufficiently large to prescribe that caution must be exercised in the use of any estimated data. The Colombian data was also compared to the U.S. civilian data which is currently used to design Colombian products (when anthropometric criteria are used at all). In terms of stature, when designing for ninety percent of the US population, only fifty-eight percent of the Colombian male population and sixty-eight percent of the Colombian female populations will be accommodated.

    INDUSTRIAL ERGONOMICS: Panel

    The Philosophy of Ergonomics Standards BIBA 678
      Brian Peacock; Gary Orr; Don Chaffin; Tom Leamon; Rob Radwin
    The panel will include speakers from Government (Gary Orr), Academia (Don Chaffin), Insurance (Tom Leamon), the HF&ES (Rob Radwin), Industry (Brian Peacock, Panel Chair), the Legal Profession (TBD) and Labor (TBD)
       After a hectic few years the promised OSHA ergonomics standard has been relegated to the back burner. Various sets of material were distributed, including a draft proposed standard along with extensive appendices. Much has been said and written regarding the scientific basis, the economic implications and the legal ramifications of the standard. Many other attempts have also been made to produce material that represents the general opinion of the profession, including ANSI Z365, the State of California and British Columbia. The issue of standards will not go away and it is probably appropriate at this time to step back and discuss some philosophical issues associated with standards.
       Operational concepts:
  • Ergonomics is broader in content and application than the prevention of acute
       and cumulative trauma disorders and so a standard should adopt a more
       specific title such as a Musculo Skeletal Disorder Prevention Standard.
  • Programmatic Guidelines should describe the general content of ergonomics
       activity such as Job Analysis, Hazard (or Error) Reduction, Training,
       Medical (or Risk) Management, Record Keeping and Reporting.
  • Performance Requirements should refer to specific outcome measures such as
       injury / illness incidence and severity, productivity, product quality and
       indications of motivation such as attendance.
  • Design Specifications should take the form of quantitative statements
       regarding systems, products, processes and environments.
  • Standards should include probabilistic statements such as target population
       selection and training characteristics and levels (percentiles) of
       accommodation, risk or protection.
  • Physical (mental) work should be optimized, not minimized.
  • Classical "reductionist" science in this area will always require
       interpolation or extrapolation before being of value in standards With these concepts in mind, each of the panelists will address the following questions:
  • 1. Is there sufficient need for a standard because of the level of outcomes
        (such as occupationally induced cumulative trauma)?
  • 2. Is there sufficient scientific evidence relating "doses" and responses to
        form the basis of a standard?
  • 3. Is our profession being fairly criticized because of our failure to reach
        agreement on standards?
  • 4. Should a standard take the form of programmatic guidelines, performance
        requirements or design specifications?
  • 5. What levels of accommodation / protection are appropriate for work standards
        and to what extent should standards assume certain levels of population
        selection and training?
  • 6. Following the analogy of the recent changes in vehicular speed limits,
        should the issue of standards be left to the individual states?
  • 7. How can consensus be achieved?
  • INDUSTRIAL ERGONOMICS: Psychophysics [Lecture]

    The Generalizability of Psychophysical Ratings in Predicting the Perception of Lifting Difficulty BIBA 679-683
      Marc L. Resnick
    Psychophysical rating scales have been used as a parameter in lifting guidelines for workers in industrial settings, used to identify musculoskeletal disorders in the workforce, and used as a surveillance tool to identify workforce discomfort. These scales can be an inexpensive and easy-to-use tool for evaluating a large variety of exertions, especially those which are difficult to evaluate using current biomechanical and physiological models because of complex dynamic or asymmetric movements. In order for these scales to be used quantitatively, however, it is essential that they consistently represent the same level of perception across different subjects and tasks. Twenty subjects rated a variety of elbow flexion exertions on the Borg CR-IO scale under two task formats. The intra-subject, inter-subject, and inter-task variations were measured. Results indicate that the Borg CR-IO scale provides a consistent measure of psychophysical perceptions across a variety of task parameters.
    A Biomechanical-Psychophysical Model of the Lifting Task BIBA 684-688
      Lisa J. Garrison; Jen-Gwo Chen
    A biomechanical-psychophysical model of the lifting task was developed. The purpose was to incorporate psychophysical attributes, such as concentration, into the lifting model. To verify the model, an experiment was performed to evaluate the biomechanical and psychophysical effects during lifting. The biomechanical model consisted of a five segment, 2-D, dynamic, model in the saggital plane. The experiment consisted of two parts; 1) subjective determination of the psychophysical maximum acceptable lifting weight and 2) gathering motion profile data as the subjects concentrated on utilizing a specified body segment while performing the lift. Computer simulated modeling of the biomechanical-psychophysical approach indicated that adding the psychophysical factor can change the resulting motion profile to lower the total body torque. The experimental data showed similar results. Total torque was reduced by concentrating on using single and multiple body segments. The significance of the results is that the lifting performance can be improved by integrating psychophysical and biomechanical properties.
    Generation of Isocomfort Working Area Based on Psychophysical Evaluation BIBA 689-693
      Eui S. Jung; Sungjoon Park; Sung H. Han
    For efficient operations, vital hand controls must be easily controlled by the operator from his or her normal working position. The primary working area based on operator's working comfort was developed to serve as a design guideline to the workplace design or the control panel layout. Six males and four females participated in the experiment in which working comfort was measured for a lever control with respect to the frontal and sagittal distances from the body center and the slope of a work table. The response surface methodology using a central composite design was employed to develop a prediction model for perceived working comfort. The concept of the proposed working area is a significant extension to the conventional working area such as Farley's or Squires' curves. It is shown that the distance to a control instrument and the slope of a work table have a quadratic effect to working comfort. It is noticeable that comfortable working area also exists outside the conventional working area. The result of the response surface analysis also indicated that a little slope of about 15° for a work table improved working comfort.
    Psychophysical Measures at Exertion: Are They Muscle-Group Dependent? BIBA 694-698
      Anpin "Max" Chin; Ram R. Bishu; Susan Hallbeck
    The purpose of the present study was to evaluate the applicability of the RPE (CR-10) scale for a number of physical exertions which employ only the upper limb with a variety of muscle group sizes and exertion levels. Ten female and ten male subjects performed pinch and pulling tasks in which four different muscle groups were engaged employing the finger, wrist, forearm and the whole arm. MVC (maximum voluntary contraction) exertion levels, RPE (Borg's CR-10 scale) value, and accuracy of the subjective assessment were measured. The results indicate that the accuracy of psychophysical measures are not muscle dependent although force generating capability is dependent on the muscle group involved. Female subjects were found more accurate in their perception of perceived exertion at lower levels of exertion than male subjects. It also appears that the RPE rating can be used to assess a variety of exertion levels accurately for a range of tasks, involving a range of muscle group sizes and location.

    INDUSTRIAL ERGONOMICS: Lifting and the NIOSH Guideline [Lecture]

    Simulation of the 1991 Revised NIOSH Manual Lifting Equation BIBA 699-703
      Waldemar Karwowski; Paul Gaddie
    Digital computer simulation of the 1991 Revised NIOSH Lifting Equation was performed using SLAM II in order to examine the behavior of this equation under a variety of realistic industrial lifting tasks. The results showed that over all conditions studied (represented by 100,000 randomly generated lifting task scenarios), the recommended weight limit (RWL) values for the 99.5% of all tasks were equal to or lower than 12.5 kg or 27.5 lbs. With respect to lifting time exposure, the RWL values for the 99.5% of cases were equal to or lower than 13 kg (or 28.6 lbs) for up to one hour of lifting, 12.5 kg (or 26.4 lbs) for less than 2 hours of exposure, and 10.5 kg (or 23.1 lbs) for lifting over an 8-hour shift. From a practical point of view, the results of this study define the threshold RWL values (TRWL), that can be used by practitioners for the purpose of immediate risk assessment of manual lifting tasks performed in industry.
    Comparison of the Prediction Models for the L5/S1 Compressive Forces under Varying Asymmetric Lifting Conditions BIBA 704-708
      Min K. Chung; Dohyung Kee; Sang H. Kim
    In this study, comparisons were made among three representative methods for predicting compressive forces on the lumbosacral disc: LP-based model, double LP-based model and EMG-assisted model. Two subjects simulated lifting tasks that were frequently performed in the refractories industry in Korea, in which vertical distance, frontal plane horizontal distance, and weight of load were varied. To calculate the L5/S1 compressive forces, EMG signals from six trunk muscles were measured and postural data were recorded using the Motion Analysis System. The EMG-assisted model was shown to reflect well all three factors considered here. On the other hand, the compressive forces of the two LP-based models were significantly affected only by weight of load. Furthermore, relatively low correlation was observed between the compressive force of the EMG-assisted model and the 1991 NIOSH lifting index (LI), while highly positive correlation was observed between that of the two LP-based models and LI.
    A Biomechanical Investigation of the Asymmetric Multiplier in the Revised NIOSH Lifting Equation BIBA 709-713
      Maury A. Nussbaum; Don B. Chaffin; George B. Page
    There is growing evidence, from epidemiological and biomechanical sources, that lifting performed in asymmetric postures is a risk factor for the development of a musculoskeletal injury. In the recent update of the NIOSH Lifting Guide, a linear Asymmetric Multiplier was added to account for this type of risk. The present study addresses the form of this Multiplier through analysis of several asymmetric lifting tasks. Both spinal loading and a derived metric of muscle injury risk were calculated as a function of asymmetry angle. The results suggest that there is a non-linear increase in injury risk with respect to asymmetry. Only moderate increases in risk were predicted for asymmetry of 0°-30°, and sharply increasing risk as asymmetry reaches 90°, implying that ergonomic intervention should be concentrated on tasks with the highest asymmetries.
    Assessment of Validity of Applying the Revised NIOSH Weight Limit of Lifts to Korean Young, Male Population: Psychophysical Approach BIBA 714-717
      Kwan S. Lee; Hee S. Park
    This investigation was aimed to study using the psychophysical method if the revised weight limit of lifts recommended by the U.S. National Institute for Occupational Safety and Health (NIOSH) can be used as a limit for the Korean workers. College students and field workers, all of whom were young males, participated in the experiment. The psychophysical experiment and the validation experiment were performed in sagittal plane where lifting frequency and lifting height varied. Main results showed the load constant obtained in this study was about the same as the one recommended in the NIOSH equation, which means that young, healthy, male Korean population can be well protected by the NIOSH equation.