- Email: [email protected]
Human factors engineering at Virginia tech
Applied Ergonomics 1994 25(3) 188-194
Ergonomics in action
Human factors engineering at Virginia Tech Virginia Tech (short for Virginia Polytechnic Institute and State University, or VPI&SU) is the land-grant university of Virginia, with approximately 24 000 fulltime students. Its home is in Blacksburg, a friendly college town (of about 11 000 people without students) at the eastern slope of the Appalachian Mountains, south from Washington, DC at about four hours of driving time. The nearest major airport is in Roanoke, about 40 min away. Over two decades ago, Virginia Tech established a Human Factors Engineering programme within the Industrial and Systems Engineering (ISE) Department. 1 The faculty, facilities, and research programme of the Human Factors Engineering Center have increased and are unsurpassed today by any academic institution in the USA. In 1985, the Human Factors Engineering Center was formally established; in 1986, it moved to occupy newly constructed laboratory and office space of about 2300 m 2.
Human Factors Engineering Center facilities The Human Factors Engineering Center has seven dedicated laboratories, supported by 11 faculty members: Auditory Systems, Displays and Controls, Environmental and Safety, Human--Computer, Industrial Ergonomics, Rehabilitation Engineering, and Vehicle Analysis and Simulation.
Auditory Systems Laboratory The Auditory Systems Laboratory is equipped to provide flexible research capabilities in the areas of psychoacoustics, auditory information display, noise, and hearing conservation. One unique speciality of this lab is that it provides rooms and instrumentation for the evaluation of hearing protection devices, including spectral attenuation and noise reduction rating (NRR) determination. It is accredited by the National Institute of Standards and Technology for acoustical testing as per ANSI $3.19-1974 and ANSI S12.6--1984 standards. Industry-sponsored and government-sponsored research efforts in the Auditory Systems Laboratory have recently focused on specific areas of audiometry and psychoacoustics, on hearing protection device design, speech communication, warning signal design, speech synthesis for in-car displays, and the effects of noise on operator performance. In addition to these acoustics-
1For more information please contact Dr R.D. Dryden at 302-A Whittemore Hall, ISE Department, Blaeksburg, VA 24061-0118, USA; fax 703 231 3322.
188
related projects, laboratory personnel perform systemsoriented research in human factors engineering, working on general control-display and environmental problems of the human-machine interface. One recently completed research project in the Auditory Systems Laboratory was aimed at determining whether controlled laboratory measurement procedures could yield realistic estimates of actual hearing protector performance achieved in the workplace. Laboratory and field studies were performed using a common set of hearing protection devices (HPDs). The laboratory experiment, using 40 naive subjects, investigated the effects of HPD wearing time, activity movement and two fitting conditions (subjectfit vs. trained-fit), on spectral attenuation afforded by a slow-recovery foam earplug, a premoulded plug, and a foam cushion earmuff. The field study, using 40 noiseexposed industrial workers, determined the actual protection obtained over six weeks of HPD use in five industrial workplaces. Statistical comparisons of the data for each protector, shown in Figure 1, demonstrated that the laboratory attenuation results significantly overestimated the field attenuation by 8.3 dB and 5.7 dB (trained-fit) for the user-moulded foam plug, and by 10 dB and 6 dB, respectively, for the premoulded plug. The laboratory results provided a much better prediction of field protection for the earmuff than for the earplugs. Because of the discrepancies between laboratory ratings and actual protection received in the workplace, special care needs to be exercised in the proper selection and fitting of protectors for the workforce. For subjects with normal hearing, speech intelligibility may actually improve in moderately high noise levels when the listener wears hearing protection, compared with unoccluded (open) ears. Although conventional protectors do not alter the speech/noise ratio, the effect is to reduce the total acoustic energy transmitted to the inner ear, at levels at which cochlear distortion is minimized, and thus better discrimination occurs (Figure 2).
Displays and Controls Laboratory The Displays and Controls Laboratory consists of several chambers, which are connected to a central room which houses computers, printers, plotters and patch panels for the laboratory interconnect system. Also available are large-screen and fiat-panel displays. The visual performance facility is designed for light control and measurement of visual performance. The basic element in the room is a Stanford Research
0003-0870/94/03 0188--07 ~) 1994 Butterworth-Heinemann Ltd
Applied Ergonomics 1994 Volume 25 Number 3
Ergonomics in action
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International Dual Purkinje Image Eye Tracker, including an Accommodation Tracker. This device is capable of making measurements at the rate of 200 samples per second of vertical and horizontal eye position (within 15 arcseconds) and accommodation (with 0.1 dioptre). The software allows automatic cataloguing of visual saccades and fixations, as well as correlated accommodation measures. The laboratory also contains a custom-built 'sunlight simulator' capable of imitating the intensity and colour of sunlight. The matrix and stereo displays facility is currently dedicated to the valuation of various parameters of matrix and stereo displays and their effects on operator Applied Ergonomics 1994 Volume 25 Number 3
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Ergonomics in action
Lighting in the chamber, as well as lighting through the laboratory, can be adjusted continuously. Temperature, relative humidity and lights are controlled manually or by a microprocessor, which provides up to 24 step changes in conditions. The time interval for each step can be individually varied. During a recently completed study on the effects of heat stress on the perceived workload in tracking, eight male unacclimatized subjects (25-35 years) performed one-dimensional horizontal compensatory tracking (the Critical Instability Tracking Task, CITT), in each of eight environmental conditions for an hour. Two levels
of ambient temperature (22 °C and 35 °C) and two levels of relative humidity (45% and 80% RH) were used, resulting in WBGTs of 18 °C, 21 °C, 29 °C and 34 °C. Two levels of tracking difficulty were employed: 1300(/)
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Figure 6 The image quality of visual displays is important for determining the usability of an interactive human-machine system. Image quality is dependent on the display's ability to present luminance contrast, as measured by the modulation transfer function (MTF), as well as on the eye's ability to perceive contrast, as measured by the contrast threshold function (CTF). This figure represents the MTF and CTF associated with an advanced sensor--display system used in military heli-copters. The MTF data are analysed in conjunction with the CTF to predict the perceived image quality of the sensor-display system. This helps to develop avionics systems that allow pilots to fly high-speed, nap-of-the-earth missions in dim daylight or at night
Applied Ergonomics 1994 Volume 25 Number 3
Ergonomics in action offices. Research in the laboratory emphasizes the development of models, measures and techniques that focus on user-centred design of real human--computer software interfaces. Simulation of electronic office configurations is also available in the laboratory to represent audio, video and computer teleconferencing activities.
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Industrial Ergonomics Laboratory The Industrial Ergonomics Laboratory is sheltered from external disturbances (no windows) and environ SWAT 43.38
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The Human-Computer Interface Laboratory is dedic ated to research on human factors problems associated with the design of systems that involve people and computers Research topics include design of h u m a n computer dialogues online computer assistance train ing users of computer systems adaptive h u m a n computer interfaces methods of measuring computer user preferences and performance empirical modelling of humancomputer interfaces design and evaluation of speech input/output devices the development of new methods and procedures for the design of h u m a n computer interfaces and the design of electronic
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191
Ergonomics in action
mentally controlled, for research, development, and evaluation in the areas of: ® engineering anthropometry, classical and functional, and related workstation and equipment design; ® biomechanics of the human body - modelling, strength, motions and working postures; • human engineering of systems, equipment, tools, workstations and work tasks; • ergonomic design for safety, efficiency and high performance of manned systems. Basic research in the past two years has addressed:
EMG patterns during movement; internal regulation and methodological assessment of voluntary muscle strength and of low-back biomechanics; biomechanics of the hand; contributions of head and eye angles to the preferred line of sight; and variables in cumulative trauma. Applications and consulting included: ergonomic design of computer workstations; suitability of work seats; development and testing of a ternary chord keyboard, and of keyboard geometry; assessment of body postures; hand performance in space gloves; a pinch strength tester; lifting capability tests; helmetmounted displays; selection of chairs; and rail car handbrakes. One example of recent work in the Industrial Ergonomics Laboratory is the testing of a series of development stages of ternary chord keyboards. This involved the original key selection and key arrangements on the board, followed by an evaluation of a prototype and finally of performance testing on the preproduction model (Figures 9 and 10). Other ergonomic work concerns the assessment of the changing anthropometric and biomechanical
capabilities as people get older, and how consequently to design the working and living environment for the elderly. Also, over-use disorders are a major ergonomic challenge: 'repetitive strain injuries' on the shopfloor, such as low-back disorders associated with manual material movement, or in the office, such as carpal tunnel syndrome (Figures 11 and 12). Rehabilitation Engineering Laboratory
The Rehabilitation Engineering Laboratory provides a comprehensive facility for assisting the mentally and physically disabled, with special emphasis on the severely handicapped. The work is in three main areas: (1) research and development of assessment methodology and general adaptive device design; (2) providing publications, seminars, workshops, and consulting services to private and governmental agencies; and (3) comprehensive testing of residual abilities of individuals with respect to employability. The research emphasis of the Rehabilitation Engineering Laboratory currently centres on three main efforts: establishing a continuum of assessment devices/instruments capable of measuring the residual abilities of clients ranging from the profoundly handicapped to the regular industry worker; developing performance measures that permit the expression of available motions inventory data in a format amenable to common industry work standards; and evaluating the feasibility of using speech input/output devices for the severely disabled.
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Figure 10 Prototype and production version of ACCUKEY®, a new chord keyboard with ternary rather than binary keys Applied Ergonomics 1994 Volume 25 Number3
Ergonomics in action
M lAP
Figure 12 Model of intra-abdominal pressure, IAP, and its resultant force vector P interacting with trunk-muscle force M and compressive force C in the spinal column. S is the shear force; T is the torque acting on spinal segments Figure 11 Code-numbered links of a 'biomechanical hand'. The code numbers follow from a total body model, in which the first digit indicates the major link (here, the right arm); the second digit is the subdivision (here, the hand); and the third digit indicates consecutive link numbering in the distal direction. The thumb ( . . . 1 ) has only four links from the wrist, while the fingers ( . . . 2 for index finger, . . .5 for little finger) have five links distal to the wrist. The letter J indicates a joint at the distal end of a link: thus the wrist joint J42 is at the end of the forearm (42). Such numbering allows the computer storage of related biomechanical data, such as mobility, excursions or torques developed around joints. This information is being used to evaluate, among other products, keyboards and other manual computer-input devices The Available Motions Inventory (AMI) allows one to evaluate the residual job-related physical abilities of individuals with neuromuscular disorders. The AMI motion class profile shows two numbers on the ordinate: the first indicates the part of the body that performs an activity; the second number indicates motion in 1, 2 or 3 dimensions or rotary (R) motion. The numbers on the abscissa r e p r e s e n t the number of standard deviations between the client's mean score and the standard mean score. Scores lower than - 3 standard deviations generally indicate that accommodations are needed. The example profile (Figure 13) shows that the client has rather poor facility with all classes of motions, but particularly with those involving the hand and forearm in a rotary pattern. All strength scores are also more than 3 standard deviations below the standard, as are most speed scores.
Vehicle Analysis and Simulation Laboratory The Vehicle Analysis and Simulation Laboratory has a computer-controlled, moving-base driving simulator, Applied Ergonomics 1994 Volume 25 Number 3
with a custom-designed six-degree-of-freedom computer-generated display. Videotaped scenes can also be used if desired. The apparent movements of the roadway images are coordinated with a hydraulically actuated four-degree-of-freedom motion base controlled by a dynamics computer. Four channels of sound and vibration are used to enhance the realism of the simulation. The simulator has an active steering servo system, making it possible to match steering feel to that of almost any vehicle. The simulator produces a surprisingly realistic impression of highway driving, thus providing a high-quality, safe test apparatus for the study of many types of automotive human factors problems. The laboratory also contains an aircraft simulator, a Singer-Link GAT1-B, which has been modified for use in research. It simulates a singleengine aircraft (Figure 14). Certain research problems involving vehicles do not lend themselves to simulation and must therefore be carried out in actual vehicles. A vehicle (on loan from General Motors) has a special power supply for data conditioning, video and computational equipment. The car has been used for human factors testing and evaluation of an in-car navigation system, and for driver workload studies (Figure 15).
The academic programme The undergraduate programme in industrial and systems engineering at Virginia Tech is scheduled to require four years, ending with the Bachelor Of Science degree. During this time, ISE students take at least two undergraduate courses in the human factors area: Work Measurement and Methods, and Introduction to H u m a n Factors Engineering. Futhermore, they have available a number of technical elective courses, 193
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Acknowledgement My colleagues in the H F E Center and Barry Grant of the HFS Student Chapter co-wrote this text. including Industrial Hazard Control, System Safety Analysis, and Work Physiology. The graduate programme consists of two scheduled years of courses, including a thesis, to reach the Master of Science degree, and two more years of studies and a dissertation for the PhD degree. These graduate degrees carry the name of Industrial and Systems Engineering with a specialization in 'human factors engineering' or in 'safety engineeering'. The human factors engineering programme is accredited by the Human Factors Society and by the Ergonomics Society. Students enter the graduate Human Factors Engineering progamme usually with a Bachelor of Science degree. If the background lacks in essential engineering aspects, make-up courses are required to compensate for individual needs. Given this flexibility, our students may have bachelors' degrees in mathematics, physics, chemistry, physical therapy, behavioural sciences, architecture or other areas, but most have an engineering education. 194
Karl H. E. Kroemer Industrial Ergonomics Laboratory Human Factors Engineering Center ISE Department Virginia Polytechnic Institute and State University VA 24061-0118 USA
This contribution describing the work of the Human Factors Engineering Center at Virginia Tech is the first in a new occasional series, 'Ergonomics in Action'. We invite contributions from centres of ergonomics research and development across the world, which describe not only the institution but current work of interest and relevance to the application of ergonomics. The Editor Applied Ergonomics 1994 Volume 25 Number 3
Ergonomics in action
Human factors engineering at Virginia Tech Virginia Tech (short for Virginia Polytechnic Institute and State University, or VPI&SU) is the land-grant university of Virginia, with approximately 24 000 fulltime students. Its home is in Blacksburg, a friendly college town (of about 11 000 people without students) at the eastern slope of the Appalachian Mountains, south from Washington, DC at about four hours of driving time. The nearest major airport is in Roanoke, about 40 min away. Over two decades ago, Virginia Tech established a Human Factors Engineering programme within the Industrial and Systems Engineering (ISE) Department. 1 The faculty, facilities, and research programme of the Human Factors Engineering Center have increased and are unsurpassed today by any academic institution in the USA. In 1985, the Human Factors Engineering Center was formally established; in 1986, it moved to occupy newly constructed laboratory and office space of about 2300 m 2.
Human Factors Engineering Center facilities The Human Factors Engineering Center has seven dedicated laboratories, supported by 11 faculty members: Auditory Systems, Displays and Controls, Environmental and Safety, Human--Computer, Industrial Ergonomics, Rehabilitation Engineering, and Vehicle Analysis and Simulation.
Auditory Systems Laboratory The Auditory Systems Laboratory is equipped to provide flexible research capabilities in the areas of psychoacoustics, auditory information display, noise, and hearing conservation. One unique speciality of this lab is that it provides rooms and instrumentation for the evaluation of hearing protection devices, including spectral attenuation and noise reduction rating (NRR) determination. It is accredited by the National Institute of Standards and Technology for acoustical testing as per ANSI $3.19-1974 and ANSI S12.6--1984 standards. Industry-sponsored and government-sponsored research efforts in the Auditory Systems Laboratory have recently focused on specific areas of audiometry and psychoacoustics, on hearing protection device design, speech communication, warning signal design, speech synthesis for in-car displays, and the effects of noise on operator performance. In addition to these acoustics-
1For more information please contact Dr R.D. Dryden at 302-A Whittemore Hall, ISE Department, Blaeksburg, VA 24061-0118, USA; fax 703 231 3322.
188
related projects, laboratory personnel perform systemsoriented research in human factors engineering, working on general control-display and environmental problems of the human-machine interface. One recently completed research project in the Auditory Systems Laboratory was aimed at determining whether controlled laboratory measurement procedures could yield realistic estimates of actual hearing protector performance achieved in the workplace. Laboratory and field studies were performed using a common set of hearing protection devices (HPDs). The laboratory experiment, using 40 naive subjects, investigated the effects of HPD wearing time, activity movement and two fitting conditions (subjectfit vs. trained-fit), on spectral attenuation afforded by a slow-recovery foam earplug, a premoulded plug, and a foam cushion earmuff. The field study, using 40 noiseexposed industrial workers, determined the actual protection obtained over six weeks of HPD use in five industrial workplaces. Statistical comparisons of the data for each protector, shown in Figure 1, demonstrated that the laboratory attenuation results significantly overestimated the field attenuation by 8.3 dB and 5.7 dB (trained-fit) for the user-moulded foam plug, and by 10 dB and 6 dB, respectively, for the premoulded plug. The laboratory results provided a much better prediction of field protection for the earmuff than for the earplugs. Because of the discrepancies between laboratory ratings and actual protection received in the workplace, special care needs to be exercised in the proper selection and fitting of protectors for the workforce. For subjects with normal hearing, speech intelligibility may actually improve in moderately high noise levels when the listener wears hearing protection, compared with unoccluded (open) ears. Although conventional protectors do not alter the speech/noise ratio, the effect is to reduce the total acoustic energy transmitted to the inner ear, at levels at which cochlear distortion is minimized, and thus better discrimination occurs (Figure 2).
Displays and Controls Laboratory The Displays and Controls Laboratory consists of several chambers, which are connected to a central room which houses computers, printers, plotters and patch panels for the laboratory interconnect system. Also available are large-screen and fiat-panel displays. The visual performance facility is designed for light control and measurement of visual performance. The basic element in the room is a Stanford Research
0003-0870/94/03 0188--07 ~) 1994 Butterworth-Heinemann Ltd
Applied Ergonomics 1994 Volume 25 Number 3
Ergonomics in action
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performance. The ratiometrics facility permits radiometric and photometric quantification of visual displays, as well as testing for conformance to ANSI and ISO Standards. Because this laboratory has a floating granite optical table, extremely accurate (1.0 Ixm) spatial measurements can be made. Figures 3-6 show some of the results of recent research work in the Displays and Controls Laboratory.
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The Environmental and Safety Laboratory consists of experimental rooms, a controls and observation room (with a one-way window) and an environmental chamber. The environmental chamber can be controlled from 0 to 44 °C, with a rate of change of 3 °C/min. The relative humidity range is from 50 to 95%, _+0.5%. 100-
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Figure 1 Attenuation of three different hearing protection devices, depending on fitting conditions and conditions of use: (a) slow-recovery foam earplug; (b) pre-moulded plug; (c) foam cushion earmuff. Lab data: using mean of post-task observations. Field data: using mean of three weekly observations
International Dual Purkinje Image Eye Tracker, including an Accommodation Tracker. This device is capable of making measurements at the rate of 200 samples per second of vertical and horizontal eye position (within 15 arcseconds) and accommodation (with 0.1 dioptre). The software allows automatic cataloguing of visual saccades and fixations, as well as correlated accommodation measures. The laboratory also contains a custom-built 'sunlight simulator' capable of imitating the intensity and colour of sunlight. The matrix and stereo displays facility is currently dedicated to the valuation of various parameters of matrix and stereo displays and their effects on operator Applied Ergonomics 1994 Volume 25 Number 3
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Lighting in the chamber, as well as lighting through the laboratory, can be adjusted continuously. Temperature, relative humidity and lights are controlled manually or by a microprocessor, which provides up to 24 step changes in conditions. The time interval for each step can be individually varied. During a recently completed study on the effects of heat stress on the perceived workload in tracking, eight male unacclimatized subjects (25-35 years) performed one-dimensional horizontal compensatory tracking (the Critical Instability Tracking Task, CITT), in each of eight environmental conditions for an hour. Two levels
of ambient temperature (22 °C and 35 °C) and two levels of relative humidity (45% and 80% RH) were used, resulting in WBGTs of 18 °C, 21 °C, 29 °C and 34 °C. Two levels of tracking difficulty were employed: 1300(/)
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Figure 6 The image quality of visual displays is important for determining the usability of an interactive human-machine system. Image quality is dependent on the display's ability to present luminance contrast, as measured by the modulation transfer function (MTF), as well as on the eye's ability to perceive contrast, as measured by the contrast threshold function (CTF). This figure represents the MTF and CTF associated with an advanced sensor--display system used in military heli-copters. The MTF data are analysed in conjunction with the CTF to predict the perceived image quality of the sensor-display system. This helps to develop avionics systems that allow pilots to fly high-speed, nap-of-the-earth missions in dim daylight or at night
Applied Ergonomics 1994 Volume 25 Number 3
Ergonomics in action offices. Research in the laboratory emphasizes the development of models, measures and techniques that focus on user-centred design of real human--computer software interfaces. Simulation of electronic office configurations is also available in the laboratory to represent audio, video and computer teleconferencing activities.
easy Q,iow= 1.0 a n d )~high ~-- 2.0) and moderate (Zlow = 1.0 and Ahigh = 5.0). Previous research had demonstrated that both ambient temperature and tracking difficulty significantly affected tracking performance and perceived workload. However, in this study, humidity did not influence either measure significantly. This might be attributed to the upper bound of humidity (80% RH) used in this research. The results indicated that the Subjective Workload Assessment Technique (SWAT) can be used as an indicator of the actual changes in mental workload on tracking in heat. Finally, results showed that tracking performance decrement occurred at a lower temperature (29 °C WBGT) than did the perception of significant mental workload on tracking (which occurred at 34 °C WBGT) (see Figures 7 and 8).
Industrial Ergonomics Laboratory The Industrial Ergonomics Laboratory is sheltered from external disturbances (no windows) and environ SWAT 43.38
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The Human-Computer Interface Laboratory is dedic ated to research on human factors problems associated with the design of systems that involve people and computers Research topics include design of h u m a n computer dialogues online computer assistance train ing users of computer systems adaptive h u m a n computer interfaces methods of measuring computer user preferences and performance empirical modelling of humancomputer interfaces design and evaluation of speech input/output devices the development of new methods and procedures for the design of h u m a n computer interfaces and the design of electronic
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191
Ergonomics in action
mentally controlled, for research, development, and evaluation in the areas of: ® engineering anthropometry, classical and functional, and related workstation and equipment design; ® biomechanics of the human body - modelling, strength, motions and working postures; • human engineering of systems, equipment, tools, workstations and work tasks; • ergonomic design for safety, efficiency and high performance of manned systems. Basic research in the past two years has addressed:
EMG patterns during movement; internal regulation and methodological assessment of voluntary muscle strength and of low-back biomechanics; biomechanics of the hand; contributions of head and eye angles to the preferred line of sight; and variables in cumulative trauma. Applications and consulting included: ergonomic design of computer workstations; suitability of work seats; development and testing of a ternary chord keyboard, and of keyboard geometry; assessment of body postures; hand performance in space gloves; a pinch strength tester; lifting capability tests; helmetmounted displays; selection of chairs; and rail car handbrakes. One example of recent work in the Industrial Ergonomics Laboratory is the testing of a series of development stages of ternary chord keyboards. This involved the original key selection and key arrangements on the board, followed by an evaluation of a prototype and finally of performance testing on the preproduction model (Figures 9 and 10). Other ergonomic work concerns the assessment of the changing anthropometric and biomechanical
capabilities as people get older, and how consequently to design the working and living environment for the elderly. Also, over-use disorders are a major ergonomic challenge: 'repetitive strain injuries' on the shopfloor, such as low-back disorders associated with manual material movement, or in the office, such as carpal tunnel syndrome (Figures 11 and 12). Rehabilitation Engineering Laboratory
The Rehabilitation Engineering Laboratory provides a comprehensive facility for assisting the mentally and physically disabled, with special emphasis on the severely handicapped. The work is in three main areas: (1) research and development of assessment methodology and general adaptive device design; (2) providing publications, seminars, workshops, and consulting services to private and governmental agencies; and (3) comprehensive testing of residual abilities of individuals with respect to employability. The research emphasis of the Rehabilitation Engineering Laboratory currently centres on three main efforts: establishing a continuum of assessment devices/instruments capable of measuring the residual abilities of clients ranging from the profoundly handicapped to the regular industry worker; developing performance measures that permit the expression of available motions inventory data in a format amenable to common industry work standards; and evaluating the feasibility of using speech input/output devices for the severely disabled.
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Figure 10 Prototype and production version of ACCUKEY®, a new chord keyboard with ternary rather than binary keys Applied Ergonomics 1994 Volume 25 Number3
Ergonomics in action
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Figure 12 Model of intra-abdominal pressure, IAP, and its resultant force vector P interacting with trunk-muscle force M and compressive force C in the spinal column. S is the shear force; T is the torque acting on spinal segments Figure 11 Code-numbered links of a 'biomechanical hand'. The code numbers follow from a total body model, in which the first digit indicates the major link (here, the right arm); the second digit is the subdivision (here, the hand); and the third digit indicates consecutive link numbering in the distal direction. The thumb ( . . . 1 ) has only four links from the wrist, while the fingers ( . . . 2 for index finger, . . .5 for little finger) have five links distal to the wrist. The letter J indicates a joint at the distal end of a link: thus the wrist joint J42 is at the end of the forearm (42). Such numbering allows the computer storage of related biomechanical data, such as mobility, excursions or torques developed around joints. This information is being used to evaluate, among other products, keyboards and other manual computer-input devices The Available Motions Inventory (AMI) allows one to evaluate the residual job-related physical abilities of individuals with neuromuscular disorders. The AMI motion class profile shows two numbers on the ordinate: the first indicates the part of the body that performs an activity; the second number indicates motion in 1, 2 or 3 dimensions or rotary (R) motion. The numbers on the abscissa r e p r e s e n t the number of standard deviations between the client's mean score and the standard mean score. Scores lower than - 3 standard deviations generally indicate that accommodations are needed. The example profile (Figure 13) shows that the client has rather poor facility with all classes of motions, but particularly with those involving the hand and forearm in a rotary pattern. All strength scores are also more than 3 standard deviations below the standard, as are most speed scores.
Vehicle Analysis and Simulation Laboratory The Vehicle Analysis and Simulation Laboratory has a computer-controlled, moving-base driving simulator, Applied Ergonomics 1994 Volume 25 Number 3
with a custom-designed six-degree-of-freedom computer-generated display. Videotaped scenes can also be used if desired. The apparent movements of the roadway images are coordinated with a hydraulically actuated four-degree-of-freedom motion base controlled by a dynamics computer. Four channels of sound and vibration are used to enhance the realism of the simulation. The simulator has an active steering servo system, making it possible to match steering feel to that of almost any vehicle. The simulator produces a surprisingly realistic impression of highway driving, thus providing a high-quality, safe test apparatus for the study of many types of automotive human factors problems. The laboratory also contains an aircraft simulator, a Singer-Link GAT1-B, which has been modified for use in research. It simulates a singleengine aircraft (Figure 14). Certain research problems involving vehicles do not lend themselves to simulation and must therefore be carried out in actual vehicles. A vehicle (on loan from General Motors) has a special power supply for data conditioning, video and computational equipment. The car has been used for human factors testing and evaluation of an in-car navigation system, and for driver workload studies (Figure 15).
The academic programme The undergraduate programme in industrial and systems engineering at Virginia Tech is scheduled to require four years, ending with the Bachelor Of Science degree. During this time, ISE students take at least two undergraduate courses in the human factors area: Work Measurement and Methods, and Introduction to H u m a n Factors Engineering. Futhermore, they have available a number of technical elective courses, 193
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motions, strengths and reaches according to AMI categories: zero is 'normal'
Acknowledgement My colleagues in the H F E Center and Barry Grant of the HFS Student Chapter co-wrote this text. including Industrial Hazard Control, System Safety Analysis, and Work Physiology. The graduate programme consists of two scheduled years of courses, including a thesis, to reach the Master of Science degree, and two more years of studies and a dissertation for the PhD degree. These graduate degrees carry the name of Industrial and Systems Engineering with a specialization in 'human factors engineering' or in 'safety engineeering'. The human factors engineering programme is accredited by the Human Factors Society and by the Ergonomics Society. Students enter the graduate Human Factors Engineering progamme usually with a Bachelor of Science degree. If the background lacks in essential engineering aspects, make-up courses are required to compensate for individual needs. Given this flexibility, our students may have bachelors' degrees in mathematics, physics, chemistry, physical therapy, behavioural sciences, architecture or other areas, but most have an engineering education. 194
Karl H. E. Kroemer Industrial Ergonomics Laboratory Human Factors Engineering Center ISE Department Virginia Polytechnic Institute and State University VA 24061-0118 USA
This contribution describing the work of the Human Factors Engineering Center at Virginia Tech is the first in a new occasional series, 'Ergonomics in Action'. We invite contributions from centres of ergonomics research and development across the world, which describe not only the institution but current work of interest and relevance to the application of ergonomics. The Editor Applied Ergonomics 1994 Volume 25 Number 3