bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the Potential Format and Content of a Cockpit Display of Traffic Information
Authors: Hart Sandra G. , Loomis Les L.
Published: July 2017

Computer-generated displays of traffic information may be available in airplane cockpits within a decade. Many questions exist, however, about the impact of such displays on the air traffic control system. The purpose of the following studies was to design suitable display(s) to be used in simulation research aimed at answering these questions. The initial approach was to solicit opinions from general aviation and airline pilots about display format, information content, and symbology after they had viewed more than 100 candidate displays and display options. The pilots' responses provided a preliminary indication of what information the potential user-population felt should be included in a traffic display. A series of later experiments was conducted to determine whether the features preferred in the pilot opinion survey would contribute to accurate and efficient pilot assessment of the spatial relationship between their own and another aircraft. A series of encounters between two aircraft were simulated in which the speed, heading, altitude, and geometrical relationship between the two aircraft were varied to allow a comparison between several graphic and symbolic formats for presenting information about the two aircraft.
Separation Discrimination in a Simulated Air Traffic Control Display
Authors: Stager Paul , Paine Trevor G.
Published: July 2017

Terminal area controllers made separation judgments concerning whether displayed pairs of aircraft were more than or less than the standard separation of 3 nautical miles (nm) apart. The pairs of aircraft varied with respect to their location on the air map, their relative orientation, and their separation. Two different map scales (40- and 55-nm radius) were used, and the controllers made 630 separation judgments on each map. The psychometric functions obtained indicated that the mean increment in separation required for discrimination was 0.14 nm. There were no significant differences in the psychometric functions for the 40- and 55-nm maps. Small, but operationally insignificant, effects on estimates of the separation between displayed aircraft were related to the location of the aircraft on the air map and to the relative orientation of targets.
On Difficulties in Localizing Ambulance Sirens
Authors: Caelli Terry , Porter David
Published: July 2017

This project investigated how difficult it is to localize sirens under normal driving conditions. It considered various positions and movement directions of ambulances with respect to the driver, and compared traditional types of sirens with a new electronic range of sirens. Results indicate that judgments of distance, location, and direction of the siren source are unreliable, since they are particularly dependent on the driving conditions and the type of siren employed. In all, one type of siren seems to produce more accurate responses than other types and, therefore, may be regarded as a safer device.
Effect of Driver's Age on Nighttime Legibility of Highway Signs
Authors: Sivak Michael , Olson Paul L. , Pastalan Leon A.
Published: July 2017

A field investigation of the effect of driver's age on nighttime legibility of highway signs was performed. Subjects of two age groups (under 25 and over 61 years of age) participated. The results indicate that legibility distances for the older subjects were 65 to 77% of those for the younger subjects with equal high-luminance visual acuity. This finding implies that older drivers are likely to have less distance (and thus less time) in which to act on the information transmitted by highway signs. Consequently, it is argued that (I) legibility standards for highway signs should not be based exclusively on data obtained from young observers and (2) standard (high-luminance) acuity tests have questionable relevance to nighttime visual performance.
Design Considerations in the Use of Factor Analysis to Study Intraindividual Processes: A Case Study of Mood in Telephone Operators
Authors: Wastell D. G. , Brown I. D. , Copeman A. K.
Published: July 2017

The relationship between the final factors and the composition of the original variance in a factor analysis is discussed, It is argued that, where factors defining intra individual processes are required, it is inappropriate to include interindividual variability in the original variance. A case study is reported illustrating this point. Factors defining intraindividual mood dimensions were obtained to assess differences in the self-rated mood of telephone operators as a function of switchboard design. Scores on a “well-being” factor were found to be lower for operators on a modern cordless switchboard than on the older style cord switchboard. The analysis also revealed significant changes in well-being and a second factor, labeled “competence,” over the working day.
Evoked Potential Amplitude as a Measure of Attention in Working Environments: A Comparative Study of Telephone Switchboard Design
Authors: Wastel D. G. , Brown I. D. , Copeman A. K.
Published: July 2017

Deficits in job satisfaction and performance have been reported among operators of modern cordless telephone switchboards relative to the operation of the older cord switchboards. The attentional demands of these switchboards were investigated using, as an index of attention, the amplitude of the cortical evoked potential (CEP) to an appropriate task-relevant event. However, no reliable differences in the CEP were obtained; nor indeed were differences in alpha activity or heart rate present. Emphasis is placed upon the methodological importance of this contribution in drawing attention to the CEP as a measure of psychological processes in applied contexts.
Sustained Visual Attention and Carbon Monoxide: Elimination of Adaptation Effects
Authors: Roche S. , Horvath S. , Gliner J. , Wagner J. , Borgia J.
Published: July 2017

Eighteen subjects performed a 1-h visual vigilance task, once during a control condition (filtered air) and once during an experimental condition (CO). The COHb level was elevated to 5% utilizing a bolus maintenance technique which raised the COHb level rapidly so that there would be no possibility of an adaptation occurring prior to vigilance testing. Physiological measurements included heart rate, blood pressure, and ventilation. Neither vigilance performance nor the physiological variables was statistically affected by the 5% COHb level. Subjects identified a significantly (p> 0.05) higher percentage of signals with the high frequency of signal presentation as compared to the low frequency under both filtered air and the 5% COHb level. Signal detection improved in 12 subjects during minutes 0-15, while 10 subjects showed improvement during minutes 31-45 with an elevated COHb level. The subjective questionnaire indicated that CO significantly (p < 0.01) decreased the subjects' confidence concerning their performance on the vigilance task, as well as causing significant (p < 0.05) irritation of the eyes and throat.
Multiple Resources, Task-Hemispheric Integrity, and Individual Differences in Time-Sharing
Authors: Wickens Christopher D. , Mountford S. Joy , Schreiner William
Published: July 2017

Forty subjects performed four information processing tasks. Three aspects of the data were examined: individual differences in time-sharing efficiency; task-related differences in timesharing efficiency; and interaction of processing codes and response hands. Results showed little concrete evidence for a general time-sharing ability; supported a multiple resource concept of attention; and favored a condition of “task-hemispheric integrity” in which the hemisphere of task processing (spatial or verbal) is the same one controlling the task responding hand (left vs. right). The implications of these results to operator performance in complex systems are discussed.
Driver Responses to High-Mounted Brake Lights in Actual Traffic
Authors: Sivak Michael , Post David V. , Olson Paul L. , Donohue Robert J.
Published: July 2017

This study evaluated brake responses of unsuspecting drivers to brake-signal presentations using a conventional brake- lamp system with and without supplemental high-mounted brake lamp(s). The signals were presented in actual traffic during the daytime at speeds of 48 to 72 kmlh. The main finding is that the signals given by the systems with one or two supplemental high-mounted brake lamps were more likely to produce a brake response by a following driver. On the other hand, the reaction times of the brake responses did not vary between the systems.
The Effect of Improvements in Motorcycle/Motorcyclist Conspicuity on Driver Behavior
Authors: Olson Paul L. , Halstead-Nussloch Richard , Sivak Michael
Published: July 2017

A study was conducted to develop and evaluate various means of making motorcycles more conspicuous. More than 30 conspicuity treatments were developed, and the most promising ones were evaluated in day and night tests involving ordinary car drivers on public roads. The tests established which conspicuity treatments effectively deterred motorists from accepting short time gaps. Findings showed that daytime conspicuity of a motorcycle is significantly improved if (1) its normal low-beam headlamp is turned on or (2) its high-beam headlamp is turned on and is modulating in intensity three times per second or (3) the motorcyclist is wearing a high–visibility (fluorescent) vest and helmet cover. Nighttime conspicuity is significantly improved when the motorcycle uses additional running lights or the cyclist is wearing a retroreflective vest and helmet cover. Given that about three out of four motorcycle accidents occur in daytime, one major conclusion drawn from the study is that the most effective means of improving daytime conspicuity (considering performance, cost, and cyclist convenience) is to require motorcyclists to drive during the day with their low-beam headlamp turned on.
Exploring Compatibility with Words and Pictures
Authors: Smith Sidney L.
Published: July 2017

A group of 92 male engineers, with comparison groups of 80 women and 55 human factors specialists, responded to an 18-item questionnaire covering various problems of potentially ambiguous display-control relations, labeling, and word usage. Some questions elicited strong commonality of response. Others illustrate response variability and group differences. Developed as a teaching aid, a questionnaire of this kind can also be used as a tool for exploring compatibility relations.
Boredom: A Review
Authors: Smith Richard P.
Published: July 2017

Psychological and psychiatric studies of boredom from 1926 to the present are reviewed. Articles concerning boredom averaged less than one paper per year during the review period. The most consistent finding has been that extroverts apparently constitute a group especially susceptible to this state, although this has not often been tested directly. Stimulus factors such as repetitiousness, lack of novelty, and monotony have been found to generate boredom. Coping strategies have been found to include daydreaming, motor restlessness, exploration, response variability, and withdrawal from the boring situation. Experimental approaches to the problem have generally been traditional. Attempts have consistently been made to relate boredom to altered or characteristic physiological states, but they have not resulted in a consensus concerning these biological variables.
Prediction and Quickening In Perspective Flight Displays for Curved Landing Approaches
Authors: Jensen Richard S.
Published: July 2017

In an empirical test of various prediction and quickening display algorithms, 18 professional pilot-subjects made four curved-path landing approaches in a GAT-2 simulator using each of 18 dynamically different display configurations in a within-subject design. Results Indicate that second-and third-order predictor displays provide the best lateral performance. Intermediate levels of prediction and quickening provide best vertical control. Prediction quickening algorithms of increasing computational order significantly reduce aileron, rudder, and elevator control responses, reflecting successive reductions in cockpit work load. Whereas conventional crosspointer displays are not adequate for curved landing approaches, perspective displays with predictors and some vertical dimension quickening are highly effective.
Evaluation of Work Station Design Factors in VDT Operations
Authors: Stammerjohn Lambert W. , Smith Michael J. , Cohen Barbarag F.
Published: July 2017

An onsite evaluation was conducted at five establishments using VDTs to examine VDT workstation designs and to compare these designs to recommendations obtained from the literature. Measurements were made of such critical design factors as keyboard height, screen height, workstation illumination, and glare. Illumination levels were generally in the 500 to 700 lx range, and questionnaire data confirmed that these levels were acceptable to most employees. A number of design problems were found in the VDT workstations, including excessive keyboard heights and screen positioning which would require excessive inclination of the head and neck for screen viewing. A majority of the operators surveyed found a number of factors to be bothersome, including screen readability, reflected glare, screen brightness, and flicker. A number of the dissatisfaction parameters were found to be related to levels of somatic (health) complaints.
Visual Fatigue and Occupational Stress in VDT Operators
Authors: Dainoff Marvin J. , Happ Alan , Crane Peter
Published: July 2017

In this study, 121 office workers whose jobs required the use of video display terminals for varying proportions of their workdays were interviewed. A semistructured interview technique was used to determine the attitudes of the workers toward their work and toward office automation. A smaller subset of this group was examined more intensively for workweek, during which time optometric measurements were taken and a mood/physical symptom checklist was administered. Results indicated a relatively high level of incidence of eye fatigue symptoms, as well as complaints regarding glare and lighting. However, the patterning of these complaints appeared to be relatively independent of job pressure and hostility toward office computerization. No consistent pattern of optometric measurements was found to be related to subjective complaints.
Responses to Different Spatial Configurations
Authors: Nasar Jack L.
Published: July 2017

The influence of variations in space on affective response has not been widely researched. This study investigated the relationship of variations in height, width/depth, and shape to affective responses. Each of 120 respondents was asked to sort, by preference, models of spaces which represented, at one-twelfth scale, all possible combinations of 2.14-m and 6.10-m heights with 1.52-m, 3.05-m, or 6.05-m widths and depths. The results of the chi-square analyses indicate that respondents felt more secure in response to models 2.44 m high than to models 6.10 m high, more pleased in response to the models of square rather than rectangular spaces, and more secure, pleased, and interested, on the average, in response to models of wide rather than narrow spaces. The need for further investigations for special populations and contexts is described and speculations about the implications of this research for use in designing actual settings are discussed.
The Assessment of Guide Sign Informational Load
Authors: Gordon Donald A.
Published: July 2017

The informational load of highway guide signs was measured in laboratory experimentation by having subjects view projected highway signs and choose the highway lanes leading to preassigned destinations. The informational load was measured in terms of response times and errors. Subjects were able to very quickly select the proper lane when they viewed common freeway signs and fictitious signs with as many as eight possible destinations. The inclusion on the sign display of unfamiliar destinations and nonguidance information did not appreciably slow subjects' responses. When the destination was not on the sign, subjects had to make navigational decisions, relating sign information to what they knew about the routes. The associated response times were significantly longer than when scanning alone was required. The findings are interpreted in terms of their implications for the design of highway signs.
Training Programs for Inspection
Authors: Czaja S. J. , Drury C. G.
Published: July 2017

Training is a neglected area for improvement of industrial inspection performance. Previous work shows that training can be effective but provides the reader with general principles rather than detailed examples of training programs. The experiment reported here gives details of two training programs devised for a complex visual inspection task. They differed only in that one (active) required the trainee to make an active response at each stage, while the other (passive) did not. Task performance for 42 subjects in three age groups showed significantly better performance (fewer errors) with the active training program. The specific error types reduced by active training were those logically related to the training program. There was a significant age decrement in performance, but it was smaller in magnitude than the difference between training programs.
Augmented Feedback in Adaptive Motor Skill Training
Authors: Cote David O. , Williges Beverly H. , Williges Robert C.
Published: July 2017

Two studies are presented in which a two-dimensional pursuit tracking task was used to teach a complex perceptual motor skill. The primary emphasis in these studies was to test the need for augmented task difficulty feedback in adaptive training situations where changes in task difficulty rather than performance improvements represent training progress. Augmented feedback was provided either auditorially or visually or both. However, no reliable effects due to feedback were found in either training time-to-criterion or transfer tracking accuracy. In both studies students trained adaptively performed more accurately in transfer.
Physiological Reactions of Female Workers in Indian Agricultural Work
Authors: Nag Pranab Kumar , Chatterjee S. K.
Published: July 2017

The physiological reactions of eight female workers in agricultural tasks and in leisure time activities were determined with a view to standardizing occupational workload. Maximal oxygen uptake (V02 max) was 1.892 L per minute. Their daily energy intake was 11.06 MJ, of which 85.4% was derived from carbohydrate. Pulmonary ventilation varied from 9.5 (pounding helper) to 26.4 (pounding alone) L/min. Maximum pulmonary ventilations in the tasks were only 27 to 31% of maximum breathing capacity. Average work pulse rate in many tasks was more than 130 beats per minute. Pounding alone or in pairs and digging dry soil are the heaviest jobs, while harvesting, transplanting, uprooting, and carrying loads are moderately heavy. Whole day energy expenditure was 10.61 MJ, of which 52% was expended for the working day, while physiological cost per unit time corresponds to 28% of V02 max The workloads of the females were within reasonable limits.
The Influence of Negative Air Ions on Human Performance and Mood
Authors: Tom Gail , Poole Marilyn Freeman , Galla Jane , Berrier Jolie
Published: July 2017

An empirical study investigating the influence of negative air ions on human performance and mood is described. The results indicate that people have faster reaction times and report feeling significantly more energetic under negative air ion conditions than under normal air conditions. Implications of the application of negative air ionizers are discussed.
Peak and Sustained Isometric Forces Applied to a Truck Steering Wheel
Authors: Sanders Mark S.
Published: July 2017

Each of 269 truck and bus drivers applied peak and sustained isometric forces to a truck steering wheel using three different hand positions. Subjects were instructed to maintain force for 15s. Mean peak torque was 147 Newton-meters (Nm). The peak torque decayed 12% in the first 5 s, 17% after 10 s, and 21% after 15 s. The torque values were compared to steering wheel torques produced during a front tire blowout in a large truck. Depending on the hand position and time relationship between the peak torque produced from the blowout and the drivers' peak torque 7 to 16% of the drivers might have lost control of the truck. The time-averaged blowout torques could probably be controlled by all subjects even 15 s after they produced their peak torque.
Predicting Driver Seeing Distance in Natural Rainfall
Authors: Bhise Vivek D. , Meldrum James F. , Forbes Lyman M. , Rockwell Thomas H. , McDowell Edward D.
Published: July 2017

Four field studies were conducted in natural rainfall to develop a model for predicting distances at which drivers are able to see other vehicles in the roadway at various time periods following stoppage of a windshield-wiper stroke. The seeing distance prediction was developed as a function of rain intensity, rain accumulation time, and ambient daylight illumination. Two situations were studied; in the first, drivers seated in a stationary vehicle detected moving vehicles, and in the second, moving drivers detected a stationary vehicle. Useful seeing distance models were developed from the field studies. Seeing distances predicted from the models developed from these earlier studies were compared with seeing distances obtained in a subsequent validation field test. Results indicated that average error in the prediction of seeing distances ranges from 9% to 23%.
The Use of Sternberg's Memory-Scanning Paradigm in Assessing Effects of Chemical Exposure
Authors: Smith Philip J. , Langolf Gary D.
Published: July 2017

This study evaluated the utility of a binary classification task in assessing the neurotoxic effects of elemental mercury. Twenty-six mercury cell chlor-alkali workers were tested on two occasions. This reaction-time paradigm provided reliable, stage-specific measures of cognitive functioning. In the two stages studied, processing times were found to increase significantly with increasing levels of exposure to mercury. The stage-specific nature of the measures used permits the inference that mercury has a locus of effect in the central nervous system.
Query Languages: Design Recommendations Derived from the Human Factors Literature
Authors: Ehrenreich S. L.
Published: July 2017

This paper reviews the human factors literature dealing with query languages. It covers natural and formal query languages, and such specific topics as quantifiers, data organization, mixed initiative dialogues, abbreviations, experimental evaluation of query language features, and research on person-to-person communication. Also discussed are issues to consider when determining a query language's suitability. A summary of the findings, in the form of a compendium of design recommendations, is presented as a result of this review.
Control and Automatic Processing During Tasks Requiring Sustained Attention: A New Approach to Vigilance
Authors: Fisk Arthur D. , Schneider Walter
Published: July 2017

Vigilance decrements are interpreted within a two-process (automatic/control) theory of human information processing, and the theoretical components of the normal vigilance curve are discussed in relation to type of processing and amount of practice. Two experiments were conducted showing significant vigilance decrements when subjects utilized effortful control processing; the normal decrement was not observed when effortless automatic processing was possible. Maximum vigilance decrements occur when subjects must continually and redundantly allocate control-processing resources. Results disconfirm the habituation hypothesis. It is concluded that structuring a task such that there is a consistent relationship between signals and noise will reduce vigilance problems. System design implications suggest that tasks should be structured to minimize continuous and repetitive control processing. Methods for developing vigilance-decrement-resistant automatic processing are discussed.
Lifesaving Releases---How Effective?
Authors: Miller Doris I. , Dahl Alison M.
Published: July 2017

This study was designed to investigate how well lifesavers are able to remember and apply release techniques. Thirty lifesavers were filmed underwater while executing releases from front, rear, and wrist holds. Neither level of lifesaving qualification nor current lifeguard status nor date of lifesaving training, nor order in which the releases were executed systematically influenced performance. Lifesavers found the rear and wrist holds more difficult to break than the front head hold. Release techniques requiring several movements and accurate application of leverage principles to rotate the victim were poorly performed. Simple thrusting-type extension movements were more easily retained and better executed than the more complex releases.
The Effect of Complexity on Interpreting "Chernoff" Faces
Authors: Naveh-Benjamin Moshe , Pachella Robert G.
Published: July 2017

The total number of irrelevant features was varied in a set multidimensional displays, called "Chernoff" faces, for which subjects were asked to make pairwise similarity judgments. The results showed that observers could not ignore distinctive irrelevant features even under strong instructions to do so, although they could ignore common irrelevant features. It is suggested that the salience of irrelevant information and the relationships between relevant and irrelevant information, rather than the amount of irrelevant information per se, are crucial factors in determining the potential for perceptual interference when using such displays.
Compulsory Seat Belt Usage and Driver Risk-Taking Behavior
Authors: Evansm Leonard , Wasielewski Paul , von Buseck Calvin R.
Published: July 2017

The danger compensation principle contends that the use of such vehicle safety features as seat belts may induce drivers to take greater risks. To test for this hypothesized effect, observational data on seat belt usage and driver risk taking were collected on 4812 drivers in Ontario, Canada, where seat belt usage is required by law. The hypothesized effect would result in higher risks taken by drivers compelled to wear seat belts, as indicated by closer following in freeway driving. Such an effect was sought by observing the difference between user and nonuser following headways and comparing it with a corresponding difference previously reported for Michigan, which has no mandatory usage law. The comparison provided no evidence of danger compensation behavior in car following. It was therefore concluded that this study presents no evidence that the safety benefits of seat belts would be diminished or neutralized by greater driver risk taking.
The Transfer of Failure-Detection Skills between Monitoring and Controlling Dynamic Systems
Authors: Kessel Colin J. , Wickens Christopher D.
Published: July 2017

Eighteen subjects either controlled or monitored the system dynamics of a two-dimensional pursuit display. Detection of changes in system dynamics was faster and more accurate when subjects controlled them when they monitored. The skill acquired by controlling transferred positively to the monitoring mode, producing enhanced detection performance. There was no transfer from the monitoring mode to the controlling mode. Monitors of automatic systems who have had prior manual experience rely upon different perceptual cues in making their detection response than do those who have had no experience. The training implications of these findings are discussed.
Assessment of Fire-Safety Symbols
Authors: Collins Belinda L. , Lerner Neil D.
Published: July 2017

Twenty-five internationally proposed symbols for fire-safety alerting were evaluated for understandability by 91 U.S. participants. Three modes of symbol presentation (slides, placards, and booklets) and two modes of participant response (definition and multiple choice) were studied. Confidence ratings and production data (drawings) were also obtained. Mode of symbol presentation had no significant effect, while definition and multiple-choice response procedures led to generally similar conclusions. Confidence ratings were useful in reconciling discrepancies between the two response methods. The understandability of the 25 symbols ranged from near zero to virtually complete comprehension. The poor performance of some critical symbols such as "exit" was noted, and some potentially dangerous confusions in meaning were revealed.
Tangible Graphs for the Blind
Authors: Lederman Susan J. , Campbell Jamie I.
Published: July 2017

This study is the first stage of a research program to develop and evaluate a tangible graphics system for the blind. In this study, comparatively simple formats, line graphs, were chosen. It was argued that a relatively direct translation from the standard visual format would provide sufficient information to the haptic system for effective tangible-graphreading performance. The results suggest that the presentation of spatial information in the form of tangible graphs is indeed a viable source of information for the blind reader, regardless of age at onset or duration of total blindness. Of four graph designs evaluated, the grid-on-graph and grid-underlay modes proved most effective in terms of performance and preference. Exploration strategies and design improvements were also considered.
Derivation of an Efficient Nonvocal Communication System
Authors: Goodenough-Trepagnier Cheryl , Tarry Evan , Prather Penny
Published: July 2017

In order to improve communication efficiency for speech-disabled users of nonvocal communication devices, a procedure has been developed that generates sets of units for use as language representation systems. Given a limit N to the number of units the user and device can accommodate, and the type of language system desired (phoneme sequences, letter sequences, or words with letters), the procedure produces sets of units that require a minimum number of selections per word of message.

One nonvocal individual trained in a system of this type (N = 400 phoneme sequences) improved communication rate by 30% over an alphabet system, despite a manual selection rate that was twice as slow with the large unit set.

Implications are drawn for improvement of communication rate, for the design of communication systems and devices, and for the development of systems for other languages.
Performance Effects of Noise Intensity, Psychological Set, and Task Type and complexity
Authors: Gawron Valerie J.
Published: July 2017

Knowledge of the effect of noise on performance is limited and is generally inconclusive. Examination of previous research indicated the need for a systematic and concurrent investigation of the effects of psychological set, type of task, task complexity (single or dual task), and noise intensity. Three states of psychological set were established by telling groups of eight subjects each that noise degrades, facilitates, or has no effect on performance. A control group was told nothing about noise effects. Three intensities of broad-band white noise (55, 70, 85 dBA) were presented over loudspeakers to each subject during the completion of a four-task, adaptive-criterion battery. The only significant main effect of noise was a facilitation of tracking performance. There were several significant interactions of noise with the other independent variables.
Training Maintenance Technicians for Troubleshooting: Two Experiments with Computer Simulations
Authors: Johnsow William B. , Rouse William B.
Published: July 2017

Aviation maintenance trainees participated in two experiments designed to assess the relative effectiveness of traditional instruction versus two types of computer simulation in the context of aircraft power-plant troubleshooting. Simulations ranged in nature from abstract, context-free problems to those involving specific aircraft power plants. Traditional instruction included reading assignments, television programs tailored to aircraft power-plant troubleshooting, and on-line quizzes. The first experiment compared the three training methods, and the second considered a mixture of the two computer simulations versus traditional instruction. The primary conclusion was that an appropriate combination of low- and moderate-fidelity computer simulations can provide sufficient problem-solving experience to be competitive with the more traditional lectureldemonstration form of instruction.
Effect of Seat Belts and Shoulder Harnesses on Functional Arm Reach
Authors: Garg Arun , Bakken G. M. , Saxena U.
Published: July 2017

A laboratory study was conducted to evaluate the effects of three different types of harnesses (lap belt, lap belt with crossed shoulder harness, and lap belt with parallel shoulder harness) on functional arm reach. Six male college students grasped a rotatable cylindrical handle as far away from the seat reference vertical line as was comfortably possible. Three different vertical heights and eight different azimuth angles were used. Contour curves for the reach envelopes are presented. The type of harness and height level had a significant effect on arm reach. Reach envelopes for the crossed and parallel harnesses were, on the average, 15 and 24% lower than the reach envelope for the lap belt. Of the three reach heights compared, the 110.5-cm reach envelope provided the greatest functional arm reach.
Extended Reading of Continuous Text on Television Screens
Authors: Muter Paul , Latrémouille Susane A. , Treurniet William C. , Beam Paul
Published: July 2017

Thirty-two subjects read continuous text for 2 h. Half read from a television screen (video condition) and half read from a book. Subjects experienced little nausea or headache in either condition. A small amount of dizziness, fatigue, and eyestrain was produced by reading, but there no significant differences between the book condition and the video condition on these measures, nor was there a difference in comprehension scores. Video subjects read 28.5% more slowly than book subjects. Possible reasons for this difference are discussed. In the video condition, the presence of proportional horizontal spacing had no effect on reading speed or comprehension. The results suggest that extended reading of continuous text on television screens is certainly feasible.
Why Alphabetic Keyboards Are Not Easy to Use: Keyboard Layout Doesn't Much Matter
Authors: Norman Donald A. , Fisher Diane
Published: July 2017

These studies demonstrate the inferiority of alphabetically organized keyboards as compared with a randomly organized keyboard and the standard Sholes (qwerty) keyboard. Use of the alphabetic keyboard requires considerable mental processing; the novice is faced with a trade-off between mental processing and visual search, and this makes different keyboard layouts equivalent. Comparison of different keyboard layouts by computer simulation of expert typing shows surprisingly little effect of keyboard arrangement for a wide class of keyboards. Performance with some alphabetical layouts is quite slow, but with others, it is within 2% of the speed achieved when using the Sholes keyboard. Performance with the Dvorak keyboard is only improved by about 5% over performance on the Sholes keyboard. The conclusion is that it is not worthwhile to use alphabetic keyboards for novice typists, nor to change to the Dvorak layout for experts. Keyboards can probably be improved, but only through radical redesign of the present physical key configuration.
Evaluation of Alternative Alphanumeric Keying Logics
Authors: Butterbaugh Larry C. , Rockwell Thomas H.
Published: July 2017

Four keying logics for the entry of alphanumeric characters were evaluated. Selection of the logics was based on their compatability with current keyboard designs used in the pilotaircraft interface, which involves communications, navigation, and other aircraft subsystems. Subjects in each of four groups learned one of the logics, and their performance was recorded on an alphanumeric keying task. Performance measures were keying speed and keying accuracy for alphabetic characters, numeric characters, character strings, and total list. Keying time for a keying logic that used 36 individual keys for each alphabetic and numeric character was significantly superior to other logics that used push-button telephone-type keyboards. Subjects were equally accurate on all logics, with an error rate of approximately 0.5%. Significant performance differences among the three matrix keyboard logics were inconsistent. Of these, performance on a keyboard with the telephone arrangement was most accurate.
Cockpit Visibility and Contrail Detection
Authors: Roscoe Stanley N. , Hull J. C.
Published: July 2017

A series of rooftop and laboratory experiments was conducted to investigate the effects of aircraft cockpit window posts on eye accommodation and the detection of simulated contrails. A window post equal in width to the interocular distance of 6.35 cm and one approximately 5 cm wider had comparable effects on accommodation, pulling focus inward from its empty-field resting distance in each case. However, the wider post seriously derogated the probability of detecting portions of contrails that appeared in the sectors of monocular visibility on either side, relative to the near-perfect single-look detectability with the nominal standard post width.
Evaluation of 20 Workload Measures Using a Psychomotor Task in a Moving-Base Aircraft Simulator
Authors: Wierwille Walter W. , Connor Sidney A.
Published: July 2017

The sensitivity and intrusion of 20 pilot workload assessment techniques were compared using a psychomotor loading task in a three degree-of-freedom moving-base aircraft simulator. The primary task was an instrument landing system approach and landing, with measures taken between the outer and middle markers. Three levels of psychomotor load were obtained by combined manipulation of random wind-gust disturbance level and pitch stability. Two rating scale measures and one control movement measure demonstrated sensitivity to all levels of load. Additionally, one time estimation measure and one pulse rate measure demonstrated sensitivity to some levels of load. No intrusion was found. The results of this experiment indicate that the sensitivities of workload estimation techniques vary widely, and that only a few techniques appear sensitive to psychomotor load.
Maximum Acceptable Weight of Lift as a Function of Material Density, Center of Gravity Location, Hand Preference, and Frequency
Authors: Mital Anil , Manivasagan I.
Published: July 2017

The effects of material density, center of gravity location, hand preference, and frequency on maximum acceptable weight of lift were determined experimentally in a laboratory study. Using the psychophysical methodology, 10 male college students performed lifting tasks involving three different materials, three frequencies, and three load center of gravity locations in the direction of the preferred or nonpreferred hand. Data analysis showed that maximum acceptable weight of lift is significantly reduced when the load center of gravity is offset in the direction of either the preferred or the nonpreferred hand. Lifting is relatively less stressful if the center of gravity offset is in the direction of the preferred hand as opposed to the nonpreferred hand. Significantly more weight is lifted when higher-density materials are used. Comparison with the data collected on industrial subjects showed similar, but significantly different, frequency trends. Isometric shoulder strength appears to be the limiting factor in predicting maximum acceptable weight of lift.
The Perception of Flicker and Glare on Computer CRT Displays
Authors: Isensee Scott H. , Bennett Corwin A.
Published: July 2017

Subjects rated their discomfort due to direct glare, reflected glare, and flicker while viewing a CRT display under various conditions of ambient illuminance, video luminance, and video polarity. The angle away from the CRT at which the subjects first noticed flicker was also measured. Levels of these design and environmental variables that minimize discomfort are suggested. Video luminance was shown to have the greatest impact on comfort. Methods of reducing glare and flicker are discussed.
Quantifying the Thermal Protection Characteristics of Outdoor Clothing Systems
Authors: McCullough Elizabeth A. , Rohles Frederick H.
Published: July 2017

This paper describes a reliable test method for measuring and comparing the heat-transfer characteristics of outdoor garments and sleeping bags. The procedure involves the use of an electrically heated mannequin located in a climate-controlled chamber. Unlike instruments that evaluate small samples of fabric, the mannequin technique reflects the effects of fabric overlap and garment design, shape, fit, and layering in the measurements. This paper also discusses the textile and human factors that affect the heat exchange between the body and a cold environment.
RESEARCH NOTE Numbering Formats for Hierarchic Lists
Authors: Smith Sidney L. , Aucella Arlene F.
Published: July 2017

People scanned lists of hierarchically numbered items in order to perform various tasks. For tasks involving location of individual items, a list of format with complete numbering resulted in superior performance. For tasks requiring perception of list structure, an alternative format with implicit numbering was equally good if not better.
Two Views of Motorist Behavior in Rural Freeway Construction and Maintenance Zones: The Driver and the State Highway Patrolman
Authors: Gardner Daryle Jean , Rockwell Thomas H.
Published: July 2017

Ohio state highway patrolmen and drivers completed two separate questionnaires designed to assess problems related to driver behavior in road construction and maintenance (C&M) zones. The highway patrolmen saw driver inattention, excessive speed, and improper driver behaviors as major causes of accidents in C&M zones and stated that most problems occur in the taper area of lane closures. Patrolmen considered rear-end collisions to be the most typical accident in these zones. The driver questionnaire revealed that when making decisions about speed and lane changes in C&M zones, most drivers rely on their own judgment and cues from other vehicles rather than on signing. Implications of the findings for the design and placement of traffic control devices in C&M zones are discussed.
The Effect of an Induced Selective Increase in Head Temperature Upon Performance of a Simple Mental Task
Authors: Hancock P. A.
Published: July 2017

Subjects performed a simple mental addition task under three counter-balanced conditions of a head temperature manipulation. In the heating condition, a temperature-controlled helmet induced a 1.01°C rise in head temperature as measured in the deep auditory meatus. A placebo condition consisted of helmet application but not activation, and the control condition monitored performance in the absence of the helmet. Results indicated that significantly more additions were accomplished under the heating compared with the two unvarying, non-heating conditions. This was not a trade of speed for accuracy, since the thermal manipulation exerted no significant effect on error rate. The work suggests that processing rate in a behavioral task is facilitated by the localized temperature increase.
An Application of Signal Detection Theory to Air Combat Training
Authors: Eubanks James L. , Killeen Peter R.
Published: July 2017

Mission-qualified F-4 pilots scheduled for training in the Simulator for Air-to-Air Combat (SAAC) flew two consecutive 2-min engagements against a computer-simulated adversary aircraft both before and after SAAC training. The SAAC models the flight characteristics of the different F-4 missile systems and was programmed to specify on a continual basis whether or not the adversary aircraft was within the pilot's weapon-firing envelope for each missile system. Data collected were used to calculate hit rates and false-alarm rates in an application of the theory of signal detectability (TSD). Relevant parameters were derived by solving for the (inferred) decision window that optimized goodness-of-fit to power-law ROC curves. The results suggest that TSD represents a promising approach to systematically studying changes in pilot decision-making behavior as a function of training.
Flying Performance on the Advanced Simulator for Pilot Training and Laboratory Tests of Vision
Authors: Kruk R. , Regan D. , Beverley K. I. , Longridge T. , Afhrliot
Published: July 2017

Simulator flying performance was compared with the results of sensory visual tests for student pilots, instructor pilots, and fighter pilots, and aircraft flying grades were compared for student pilots. Simulator tasks were formation flight, low-level flight, bombing, and restricted-visibility landing; visual tests were super-threshold velocity discrimination of a radially expanding flow pattern, manual tracking of both motion in depth and motion in the frontal plane, motion thresholds and contrast thresholds for a moving square, and a static sinewave grating.

Landing and formation-flight performance correlated with both manual tracking and expanding flow pattern test results. Pilots who were better able to discriminate different rates of expansion of the test flow pattern achieved a greater percentage of hits and near misses in the low-level flight and bombing task. Aircraft flying grades for student pilots correlated with expanding flow pattern test results and with manual tracking of motion in depth. These findings suggest that tests of visual sensitivity to super-threshold motion might usefully be added to current selection tests for flying personnel. They also emphasize the importance of accurate, artifact-free representation of motion in simulator visual displays.
An Isoinertial Technique to Assess Individual Lifting Capability
Authors: Kroemer Karl H. E.
Published: July 2017

Musculoskeletal overexertion injuries, particularly of the low back, are a major problem in industries in which material handling is done by workers. As increasing numbers of injuries indicate, techniques to select persons suitable for material handling need to be improved. After discussing human body functions strained in manual lifting, this paper assesses techniques used to measure the reactions of such body-response variables. Based on this evaluation, a new dynamic testing technique has been developed and used in experiments with 39 subjects. The new isoinertial test has proven to be easily applied and reliable in its results.
A Comparison of Intraabdominal Pressure Increases, Hip Torque, and Lumbar Vertebral Compression in Different Lifting Techniques
Authors: Troup J. D. G. , Leskinen T. P. J. , Stalhammar H. R. , Kuorinka I. A. A.
Published: July 2017

Intraabdominal pressure (IAP), movements of the body in the sagittal plane, and the forces applied to the load were recorded while 10 male subjects lifted or lowered a 15-kg box using six different lifting techniques and two lowering techniques. IAP data were compared with calculated peak values of lifting velocity, lumbosacral compression and hip torque, and with the integral of lumbosacral compression over time. No consistent relationship between IAP increases and any one of these values emerged. The variation in peak IAPs was considerable. Nonetheless, there were significant differences in IAP between different lifting and lowering techniques. IAP was, in general, less when the trunk was flexed for lifting and lowering than when it was used in a posture nearer to the vertical.