bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Asymmetric Transfer and Speech Technology on Dual-Task Performance
Authors: Damos Diane L.
Published: July 2017

Sixteen male subjects performed a visual short-term memory task and a verbal short-term memory task alone and together. Half of the subjects responded manually to the verbal short-term memory task using a keypad; the other half responded vocally using a speech recognition system. Stimuli for the verbal memory task were presented either auditorily by a speech generation system or visually on a CRT; the order of stimulus modes was counterbalanced within each response group. Only the use of the speech generation system initially appeared to have a beneficial effect on dual-task performance. However, asymmetric transfer occurred under dual-task conditions between the combination using visual stimuli for both tasks and the combination using auditory stimuli for the verbal task. When the data affected by asymmetric transfer were eliminated, speech technology had little effect on dual-task performance. Possible explanations for this result are given.
Optional Stopping Performance under Graphic and Numeric CRT Formatting
Authors: Schwartz David R. , Howell William C.
Published: July 2017

Two experiments sought to determine whether and if so, how, performance varies as a function of the manner in which a progressively unfolding decision problem is displayed over time. A hurricane-tracking scenario was adapted to the “optional-stopping” paradigm, such that subjects elected to continue sampling information or to make a terminal decision (evacuate or stay) at successive points in the storm's development based upon cumulative evidence and future expectations. The display manipulation was minimal in that it applied only to nonpredictive historical data (position information). Despite this conservative test, display formation had a significant effect when time pressure was involved: subjects reached earlier and better terminal decision under the graphic than the numerical format (Experiment 2). The differences reduced to nonsignificance under self-pacing (Experiment 1), although significant improvements were obtained by use of a simple aiding device (calculation of worst-case probabilities). Results are generally consistent with Hammond's cognitive consistency theory.
Viewer Evaluations of Simulated Teleshopping Presentations: Effects of Image Complexity and Image Completion Time
Authors: Mills Michael I. , Hearty Paul J.
Published: July 2017

An experiment examined the effects of image complexity (high-detail color photograph or low-detail black and white line drawing) and image completion time (0, 45, or 90 s) on viewer evaluations of simulated teleshopping presentations. Viewers rated utility, object identifiability, image fidelity, and annoyance at image completion delay. In utility ratings, viewer reactions were most favorable for high-complexity images displayed instantaneously; delayed image completion and simplified imagery led to reduced incidence of “useful” ratings. Other viewer responses suggested that utility judgments were combined opinions of image fidelity and of annoyance at completion delay rather than reflections of the identifiability of the objects shown. The implications of the results for service design and assessment were explored.
On Scaling Performance Operating Characteristics: Caveat Emptor
Authors: Kantowitz Barry H. , Weldon Marysue
Published: July 2017

Problems associated with scaling and normalizing empirical performance operating characteristics (POCs) are examined. Normalization methods proposed by Wickens (1980) and by Mountford and North (1980) are critically evaluated. Computer simulations are used to generate raw-score and normalized POCs. The interpretation of transformed empirical POCs (Wickens, Mountford, and Schreiner, 1981) is shown 10 contain inconsistencies. The normalization techniques reviewed fail to resolve POC scaling problems. Caution must be exercised when interpreting transformed POCs.
POCs and Performance Decrements: A Reply to Kantowitz and Weldon
Authors: Wickens Christopher D. , Yeh Yei-Yu
Published: July 2017

This paper responds to some of the criticisms presented by Kantowitz and Weldon (1985) that have been directed toward the methodology used in a 1981 article by Wickens, Mount-ford, and Schreiner. We state here that some of their criticisms are valid: A performance operating characteristic (POC) cannot be derived from a single point in a POC space, and therefore resource competition cannot be separated from concurrence cost as a source of task interference. However, we also note that the primary issue of importance to system designers---how to compare interference between different tasks---is not answered by Kantowitz and Weldon's critique. That issue requires that some technique for standardizing performance decrements across tasks be assumed. Two alternate techniques for standardizing are described in the present paper.
The Design and Evaluation of the Neutral Posture Chair for Surgeons
Authors: Congleton J. J. , Ayoub M. M. , Smith J. L.
Published: July 2017

A neutral posture chair was designed and evaluated to determine if it was a possible means for reducing or eliminating fatigue experienced by surgeons because of seated body posture during microsurgical procedures. The neutral body posture is defined as the posture found in weightlessness, where the muscle, tendon, and ligament systems acting over the joints are in total balance. The neutral posture chair is a unique combination of a forward-sloping cultivator seat and WI English saddle, with wraparound leg trough support. On subjective questionnaires, surgeons rated the neutral posture chair as being generally superior to a currently utilized surgical chair for general comfort, body-part comfort, and chair features.
Multimodal Detection and Recognition Performance of Sonar Operators
Authors: Kobus D. A. , Russotti J. , Schlichting C. , Haskell G. , Carpenter S. , Wojtowicz J.
Published: July 2017

Trained sonar operators participated in a detection and classification task. Stimuli were presented in three conditions: auditory and visual modalities independently and simultaneously (multimodal). The signal-to-noise ratio (SIN) was continually increased during a trial, and the elapsed time as well as the SIN level at detection and classification were recorded. The best modality for target detection was found to be target specific. However, the multimodal condition was not significantly different from the single best modality and, therefore, should be used for initial target detection in the operational setting. Differences from findings in previous studies are discussed.
Daylight Conspicuity of Reversible-Lane Signal Systems
Authors: Strybel Thomas Z. , Nassi Richard
Published: July 2017

This investigation compared the conspicuity of two traffic signal-light systems for improving the use of peak-hour reversible and dual-use two-way left-turn lanes. The systems considered were the conventional lane-use control signals and a new system of revolving beacons. Six drivers were asked to identify various characteristics of the signals at two distances (91 and 244 m) and three viewing angles (0, 0.9, and 0.17 rad), which approximated a motorist's view from different positions on a five-lane street. At 0 rad, detection and recognition of both signal-light systems was quite good. However, at more extreme viewing angles, the revolving beacon system was detected and recognized more often. It was concluded that the revolving beacon system would be more conspicuous to a driver attempting to enter the reversible lane.
Preferred Declination of the Line of Sight
Authors: Hill Susan G. , Kroemer Karl H. E.
Published: July 2017

This research concerned the angle at which people prefer to look down at visual targets and tasks. Thirty-two subjects participated in a study with four different head positions, two visual tasks, and two target distances. The overall preferred mean angle in the midsagittal plane below the Frankfurt Plane was -34 deg. Head position had significant effects on angle: subjects sitting with their heads upright preferred an average declination of -29 deg, but -40 deg when supine. Target distance also significantly affected the line-of-sight angle, with subjects preferring targets at 0.50 m to be at -38 deg, but targets at twice that distance at -30 deg. The task did not influence the preferred angle.
Visual Accommodation and Virtual Image Displays: Target Detection and Recognition
Authors: Norman Joel , Ehrlich Sharon
Published: July 2017

Twelve subjects performed a complex task, detecting and recognizing small targets presented at infinity, while simultaneously monitoring a virtual image display (VID). The VID was presented at one of four optical distances (2.0, 0.5, 0.0, and-0.5 D). Optical distance was found to affect detection and recognition performance, mainly at the extreme value of 2.0 D. Interactions between optical distance and grouping of subjects according to measures of accommodation indicated that the three other optical distances affect performance differentially. The subjects' resting position of accommodation (RPA) and a combined measure of accommodation range and RPA were significantly correlated with performance (0.58). A narrowing of the functional visual field (complete misses of peripheral targets) was found at the 2.0-D optical distance for all subjects, and at the other optical distances for the subjects with an inferior accommodative mechanism (i.e., a near RPA and/or a narrow accommodation range).
Bent Hammer Handles
Authors: Konz Stephan
Published: July 2017

The literature suggests that when a tool, gripped with a power grip, has its working part extend above the hand, then a curve in the handle may be beneficial. Three experiments investigated different angles for hammer handles. A small bend (5 to 10 deg) seems best.
Coupling the Hand with the Handle: An Improved Notation of Touch, Grip, and Grasp
Authors: Kroemer Karl H. E.
Published: July 2017

This is a classification of hand-handle couplings by the geometrical interactions between handle surfaces and anatomical sections of the hand.
The Effect of Number Ordering and Orientation on Marking Speed and Errors for Mark-Sensed Labels
Authors: Maddox Michael E. , Turpin James A.
Published: July 2017

Mark-sensed data recording has been used for many years by standardized testing companies, opinion-gathering organizations, and others. Mark-sensed forms provide a relatively efficient method for people to enter data directly on a machine-readable medium. However, there is a distinct paucity of performance data on the effects of several variables on the marking performance of individuals using mark-sensed forms. The present study manipulated three such variables in an attempt to determine whether users' performance on a zip code marking task was affected. These variables were number orientation (horizontal and vertical), number ordering (bottom-to-top and top-to-bottom for the vertical orientation), and handedness of users. Marking speed, marking errors, and error category were the dependent variables. None of the independent variables significantly affected subjects' performance.
Statistical Dependency in Visual Scanning
Authors: Ellis Stephen R. , Stark Lawrence
Published: July 2017

A method to identify statistical dependencies in the positions of eye fixations is developed and applied to eye movement data from subjects who viewed dynamic displays of air traffic and judged future relative position of air craft. Analysis of approximately 23 000 fixations on points of interest on the display identified statistical dependencies in scanning that were independent of the physical placement of the points of interest. Identification of these dependencies is inconsistent with random-sampling-based theories used to model visual search and information seeking.
The Effect of Perspective Geometry on Judged Direction in Spatial Information Instruments
Authors: McGreevy Michael Wallace , Ellis Stephen R.
Published: July 2017

As part of a study of spatial information transfer, eight subjects judged the directions of displayed targets relative to a fixed reference position in the center of each of 640 perspective images. The stimulus images subtended 18 deg of the observer's visual field, while the images were constructed with geometric fields of view ranging from 30 to 120 deg. Target elevation is consistently overestimated, especially in “telephoto” images. Azimuth error varies sinusoidally with the azimuth direction of the target, alternating between clockwise and counterclockwise errors from one direction quadrant to the next. The direction of this azimuth error gradually reverses in each quadrant as the perspective is varied between “telephoto” and “wide angle” views, so that clockwise azimuth error becomes counterclockwise error, and vice versa. The amplitude of the sinusoidal azimuth error is least in the images with a 60-deg field of view. We propose a geometrical model of an interpretive behavior associated with viewing perspective displays in which the sinusoidal pattern of azimuth errors is induced by the difference between the 3D stimulus and its 2D projection, and by the consequences of the geometric differences between the station point and the observer's actual eye position.
An EMG Analysis of Posterior Trunk Musculature during Flat and Anteriorly Inclined Sitting
Authors: Soderberg Gary L. , Blanco Mary K. , Cosentino Theresa L. , Kurdelmeier Kathy A.
Published: July 2017

The purpose of this study was to determine the differences in the electromyographic (EMG) activity of the posterior musculature of the trunk while subjects were first seated on a conventional chair, and then while the chair surface was inclined anteriorly to 100 and 110 deg. Twenty healthy subjects had electrodes applied lateral to the spinous processes of C6, T10, and L3 while EMG was monitored every other minute for 15 minutes. All subjects assumed each posture and used a keyboard to operate an interactive computer terminal. Before analysis, all data were processed by root-mean-square circuit and normalized to the EMG from maximum voluntary contractions. Analyses of variance showed significant differences (p < 0.0005) between postures; the EMG activity was found to be less with greater inclination of the chair seat.
Simulation of the After-Reach Hazard on Power Presses Using Dual Palm Button Actuation
Authors: Pizatella Timothy J. , Moll Michael B.
Published: July 2017

This paper describes a study of the after-reach hazard when a power press simulator is used. The after-reach hazard occurs when a worker reaches into a point of operation on a power press after the press cycle has been initiated. The hand-reach speed of industrial workers was measured to quantify the after-reach hazard and to determine variables that may affect after-reach movements. Significant differences in hand speed were identified, which were based on the age and gender of the worker. The location of the dual palm buttons in relation to the point of operation also significantly affected hand speed. Male workers who were 30 years of age or younger demonstrated the fastest hand speed and thus appear more likely to sustain a traumatic injury due to the after-reach hazard. The results of this study are compared with current federal standards.
Comparison of Speech and Pictorial Displays in a Cockpit Environment
Authors: Robinson Christopher P. , Eberts Ray E.
Published: July 2017

A current trend in cockpit design is to incorporate synthesized speech to present secondary information. Multiple-resource theories of information processing support this, but theories of stimulus/central-processing/response compatibility suggest that spatial information presented visually may have some advantages over speech if the response is manual. Two experiments compare response performance over single and dual tasks when information was presented pictorially and by speech. Pictorial subjects responded more quickly than did speech subjects. The addition of the visual tracking task in the dual-task condition had a differential effect on performance, depending on the modality of the primary task and the rate at which information was presented. The dual task impeded performance more in the fast and medium presentation rates for the speech condition but had little differential effect across rates for the pictorial condition. Analysis of the error data indicated that subjects in the pictorial condition were better able to maintain the context of the emergency than those in the speech condition. Results are discussed in terms of current theories of information processing.
Cognitive Factors in User/Expert-System Interaction
Authors: Lehner Paul E. , Zirk Deborah A.
Published: July 2017

Expert systems are a type of decision aid that has emerged from the field of artificial intelligence. In this paper, it is hypothesized that two cognitive factors are important mediators of the quality of user/expert-system interaction: (1) the degree of consistency between the user's problem-solving and that of the expert system, and (2) the user's mental model of the system's operating processes. It is further hypothesized that when a user possesses an accurate mental model of expert-system processing, user/expert-system performance will remain high even when there is significant inconsistency between the problem-solving processes of the user and the expert system. Three experiments testing the impact of a user's mental model on user/expert interaction are summarized. Results support the preceding hypotheses.
Operator Effort and the Measurement of Heart-Rate Variability
Authors: Aasman Jans , Mulder Gijsbertus , Mulder Lambertus J. M.
Published: July 2017

This paper discusses the usefulness of heart-rate variability (sinus arrhythmia) as an index of operator effort. Effort is involved if task performance requires the use of attention-demanding, controlled processing. This form of processing heavily uses a capacity-limited mechanism: working memory. Effort is also required if the current state of the subject deviates from the target or task optimal state because of fatigue, circadian rhythm, time of day, sleep deprivation, time on task, drugs, heat, or noise. Effort is involved whenever an attempt to resolve mismatch of target and current state takes the form of active manipulation of cognitive resources. We argue that spectral analysis of sinus arrhythmia is useful to obtain more insight into the physiological mechanisms that underlie heart-rate variability. In the present study, it is shown that the amplitude of the 0.10-Hz component of this signal systematically decreases as the load on working memory increases. Some suggestions are made to apply the methods and techniques discussed in this investigation.
Beyond Heart Rate in the Cardiac Psychophysiological Assessment of Mental Effort: The T-Wave Amplitude Component of the Electrocardiogram
Authors: Furedy John J.
Published: July 2017

The paper begins with an argument for going “beyond” heart rate for greater specificity in the measurement of mental effort. The added measure must reflect sympathetic nervous system (SNS) influences more clearly than does heart rate, which is predominantly influenced by parasympathetic factors. In considering what the human factors practitioner is seeking in the SNS measure, I discuss three requirements, the issue of convenience, and two marginally relevant considerations. The characteristics of T-wave amplitude (TWA) are then examined in this light. Recent evidence for the utility of TWA used jointly with heart rate as a psychophysiological index is then reviewed in terms of reactive sensitivity, specific sensitivity, complementary utility, and physiological utility. There follows a section that considers difficulties and confounding possibilities concerning TWA. The paper concludes that, although controversial, TWA appears to provide a promising psychophysiological path for using cardiac performance measures to aid in the measurement and understanding of the psychological process of mental effort.
Improving Visual Performance through Volitional Focus Control
Authors: Roscoe Stanley N. , Couchman Donald H.
Published: July 2017

Nine undergraduate students were trained to control eye accommodation volitionally and, by exercising that acquired ability, to improve by varying amounts their visual acuity, contrast sensitivity, and flash target resolution. Six of the nine received auditory biofeedback of focusing responses measured automatically by a complex infrared tracking optometer and monocular focus stimulator, whereas the remaining three used a relatively simple polarized vernier optometer that provides visual feedback of eye accommodation, and an even simpler binocular focus stimulator. Performance improvements were elicited by both methods, but larger gains were attained in far less time with the simpler approach, in which training is mainly self-administered.
Hesitations in Continuous Tracking Induced by a Concurrent Discrete Task
Authors: Klapp Stuart T. , Kelly Patricia A. , Netick Allan
Published: July 2017

Subjects performed continuous, visually guided pursuit tracking with the right hand while giving simultaneous discrete left-hand responses, which were signaled by auditory tones appearing at the average rate of one tone per 30 s. This left-hand secondary task was frequently associated with tracking hesitations lasting 333 ms or longer. The rate of occurrence of these hesitations was about the same when the left-hand response involved a choice between competing responses as when the left hand responded in a previously specified direction. Hesitations occurred for three different mechanical tracking manipulanda using different controlling muscles and appeared to be due to active muscular freezing rather than to relaxation. The rate of hesitations declined with practice, and this improvement in right-hand performance was accompanied by an improvement in performance of the concurrent left-hand response.
Effects of Functionally or Topographically Presented Process Schemes on Operator Performance
Authors: Vermeulen Jaap
Published: July 2017

Two presentation modes of process schemes were compared in a supervisory control task. Operators Monitored a submarine's trim system and had to identify process states and execute control orders. It was expected that the presentation of a functional arrangement would result in shorter identification times and fewer control errors than would a topographical arrangement. Results showed no differences between the two presentation modes with regard to the time required to identify a particular process state. The time needed to perform control settings was shortest in the functional presentation mode, but this effect decreased with practice. In both presentation modes, experienced subjects performed better than inexperienced subjects. The results were in line with expectations, except for a significant error increase with practice in the functional presentation mode. It is suggested that this effect is due to subjects relying increasingly on memory rather than on the presented information.
Vigilance Research—Are We Ready for Countermeasures?
Authors: Mackie Robert R.
Published: July 2017

It is argued that despite the large volume of vigilance research, only limited progress has been made in formulating principles and testing countermeasures aimed at minimizing the vigilance problem. In part this is because of the way we design our experiments, including the use of esoteric tasks, limited watch durations, and sterile experimental environments. More rapid progress toward knowledge that can be applied to real-world tasks requiring vigilance will be made if we pay greater heed to the critical features of operational tasks in designing our laboratory experiments. Examples are provided of how specificity of human responses to stimulus, temporal, and environmental variables in vigilance experiments could have led investigators to totally erroneous conclusions about the presence of the vigilance decrement and the effectiveness of potential countermeasures. The argument that basic research leads to generalizations of greater scientific power than research studies modeled after real-world conditions is challenged.
Information Transfer Rate with Serial and Simultaneous Visual Display Formats
Authors: Matin Ethel , Boff Kenneth R.
Published: July 2017

Information communication rate for a conventional display with three spatially separated windows was compared with rate for a serial display in which data frames were presented sequentially in one window. For both methods, each frame contained a randomly selected digit with various amounts of additional display “clutter.” Subjects recalled the digits in a prescribed order. Large rate differences were found, with faster serial communication for all levels of the clutter factors. However, the rate difference was most pronounced for highly cluttered displays. An explanation for the latter effect in terms of visual masking in the retinal periphery was supported by the results of a second experiment. The working hypothesis that serial displays can speed information transfer for automatic but not for controlled processing is discussed.
Cognitive Engineering: Human Problem Solving with Tools
Authors: Woods D. D. , Roth E. M.
Published: July 2017

Cognitive engineering is an applied cognitive science that draws on the knowledge and techniques of cognitive psychology and related disciplines to provide the foundation for principle-driven design of person-machine systems. This paper examines the fundamental features that characterize cognitive engineering and reviews some of the major issues faced by this nascent interdisciplinary field.
Speech Responses and Dual-Task Performance: Better Time-Sharing or Asymmetric Transfer?
Authors: Vidulich Michael A.
Published: July 2017

It has been proposed that using speech controls could improve time-sharing efficiency in environments previously dominated by manual controls (e.g., military aviation). However, it has been suggested that the research supporting the use of speech controls was potentially contaminated by asymmetric transfer. The present study examined the value of speech controls in a dual-task experiment that also evaluated asymmetric transfer effects. Despite significant effects supporting the advantage of mixing manual and speech responses, there was no evidence of asymmetric transfer. Thus although asymmetric transfer remains an experimental design concern, it is not a sufficient explanation for the observed response modality effects. The results suggested that speech controls can be used to enhance performance in operational multiple-task environments.
Task-Sharing within and between Hemispheres: A Multiple-Resources Approach
Authors: Polson Martha Campbell , Friedman Alinda
Published: July 2017

The assumption that there are qualitatively different information-processing resources has important implications for human performance. We first review some issues involved in isolating independent resource types and then present our own model, which proposes that each cerebral hemisphere accesses an independent resource supply that can be shared among many types of tasks, including those with no obvious similarities. The available evidence indicates that the model is viable. Its implications for human factors are, first, that tasks mayor may not overlap in their resource demand, and the only way to determine this reliably is with a task emphasis manipulation. Second, neither modality (visual versus auditory) nor code (verbal versus nonverbal) predicts interference as well as the particular hemisphere(s) involved in processing. Limitations of a multiple-resources approach are also discussed.
Visual Displays: The Highlighting Paradox
Authors: Fisher Donald L. , Tan Kay C.
Published: July 2017

Office computer users view well over a billion displays in a given year. The savings of only a fraction of a second in the time it takes users to process each display can potentially lead to enormous time and cost savings. In recent research investigators have shown that on average subjects are quicker to find a target option in a highlighted display than in a display without highlighting. Paradoxically, in related research other investigators have shown that subjects are slower to find a target in a highlighted display than in a display without highlighting. In an attempt to resolve this paradox, an additional set of experiments was performed. Results from these experiments suggest that in order to determine whether highlighting will be of benefit, one must know the type of highlighting, the level of highlighting validity, and the probability that subjects attend first to the highlighted options.
Visual Accommodation and Target Detection in the Vicinity of a Window Post
Authors: Chong Jenny , Triggs Thomas J.
Published: July 2017

The visual environment of a driver in a car or a pilot in an airplane has intervening objects from the vehicle such as A-pillar posts between the windscreen and the doors in the car or cockpit pillars in the airplane. The presence of such objects can bias the observer's visual accommodation response because of the Mandelbaum effect (e.g., Owens, 1979). When subjects were allowed to focus toward a distance by looking through a large aperture in an intervening post, the detection (monocular) of a briefly presented distant target was found to be significantly better than when no aperture was present. When the size of the aperture was decreased from 2.3 to 1.15 deg diameter, target detection performance was significantly decreased and remained constant as further reduction of foveal cues was made. Although the detection results were generally in agreement with the visual accommodation results, detection accuracy changed significantly only with marked changes in accommodation. In addition to an accommodation bias, interference to target detection was also observed for those targets occurring at a laterally proximal position to the intervening object.
Visual Performance on CRT Screens and Hard-Copy Displays
Authors: Harpster Jeffrey L. , Freivalds Andris , Shulman Gordon L. , Leibowitz Herschel W.
Published: July 2017

Three experiments examined the effect of hard-copy print and CRT screens of different resolution/addressability ratios (RAR) on accommodation and visual search performance. Three different display modes were generated with an IBM personal computer and a Princeton Graphics Terminal: capital letters in high-RAR mode, capital letters in low-RAR mode, and capital letters in high-RAR mode programmed to simulate the low-RAR mode. Same-sized letters were also presented on hard-copy print. Experiment 1 demonstrated that accommodation to hard-copy print and high-RAR screens was more accurate than to low-RAR screens. In Experiment 2 the spatial frequency channels activated by each display were evaluated by measuring the effect of display adaptation on the contrast-sensitivity function. The results suggested that high-RAR screens and hard-copy print activated higher-frequency channels than did low-RAR screens. In Experiment 3 significantly better visual search performance was obtained for high-RAR screens and for hard-copy print than for low-RAR screens. It was concluded that screen RAR is an important variable to consider in the design of CRTs.
Finding a Subset of Stimulus-Response Pairs with Minimum Total Confusion: A Binary Integer Programming Approach
Authors: Theise Eric S.
Published: July 2017

Confusion matrices are a convenient and widely accepted means of tabulating results from experiments in which subjects choose responses to various stimuli. This paper is relevant to studies in which the recognition and confusability characteristics of a large set of possible stimuli are tested in order to select the smaller subset of stimuli that will eventually be presented to the user (e.g., selecting sculpted pushbuttons or command words for voice-interactive systems). Rather than applying cluster analyses, this paper demonstrates how to formulate optimization models from the information contained in a confusion matrix. Four binary integer programming models are proposed that when solved, yield the subset of stimuli exhibiting minimum total confusion. The models are solvable using widely available software on a microcomputer. A sizable example from the literature is solved and discussed, and directions for algorithmic research are recommended.
Maps or Analogies? A Comparison of Instructional Aids for Menu Navigation
Authors: Webb Jayson M. , Kramer Arthur F.
Published: July 2017

We investigated the relative efficacy of a variety of spatial maps and analogies as instructional aids for the learning and navigation of hierarchical data bases. Subjects performed single- and multi-node retrieval tasks with novel data bases. The results of Experiment 1 indicated that subjects who studied an analogy prior to performing data retrieval tasks were less affected by increasing search distance than were subjects who studied a spatial map. The results of Experiment 2 suggested that the benefits of analogy relative to other instructional aids increased as time passed between initial instruction and interaction with the data base. A comparison of the findings in Experiments 1 and 2 indicated that “generic” analogies, which can be applied to a number of data bases, are as effective as more specific, literal similarities. The findings are discussed in terms of models of analogy as well as implications for the design of instructional materials for data base navigation.
The Relation of Vergence Effort to Reports of Visual Fatigue Following Prolonged Near Work
Authors: Tyrrell Richard A. , Leibowitz Herschel W.
Published: July 2017

Two experiments examined the link between vergence effort and subjective reports of visual fatigue following prolonged near work. In Experiment 1, dark vergence and reports of visual fatigue symptoms associated with computer use were measured in 104 persons. Dark vergence was significantly correlated with four of six symptoms of visual fatigue. In Experiment 2, 16 subjects who exhibited clear “Heuer effects” (systematic gaze-related changes in dark vergence) read from a video display terminal (VDT) at a distance of 20 cm for 60 min under two gaze elevation conditions: 20 deg above and 20 deg below a baseline gaze elevation. This manipulation was designed to vary the amount of vergence effort required to fixate the VDT. Results indicate a positive relation between vergence effort and visual fatigue both within and between subjects, and that prolonged near work leads to decreased vergence accuracy at far distances. Implications for VDT workstation design are discussed.
State of the Art in Automotive Adaptive Equipment
Authors: Koppa Rodger J.
Published: July 2017

Although some forms of automotive adaptive equipment designed to enable people who are physically disabled to drive have been on the market for many years, development has been slow until the last 10 to 15 years. Advanced-design, reliable devices have recently become available to allow persons who are severely disabled to gain transportation independence. Equipment for ingress/egress, primary and secondary control, and occupant protection have come on the market or are nearly ready for procurement. Much remains to be done, however, especially in integrating this equipment into a system for transportation. Primary controls (throttle, brake, and steering) and occupant protection still require much research and development. Cost, liability considerations, and a small market demand restrict development, but real progress has been made.
Computer Anxiety and Alienation: Toward a Definitive and Parsimonious Measure
Authors: Ray Nina M. , Minch Robert P.
Published: July 2017

An attempt is made to construct a useful and theoretically sound scale that can be used in future research to measure computer user anxiety and alienation. Because the measurement of either alienation or anxiety often produces similar results, the authors present a concise and reliable measure that is a synthesis of the two constructs. Findings show no differences attributable to age or sex but that number of years of computer experience is a significant indicator of the measure. The scale reported here has been successfully used to predict students' grades in computer-related classes and the level of satisfaction students have with their computer experiences.
Lumbar Motion Response to a Constant Load Velocity Lift
Authors: Mirka Gary A. , Marras William S.
Published: July 2017

An experiment was performed to evaluate the motions of the lumbar spine during a constant load velocity lift. For the purposes of this study, a constant load velocity refers to the linear vertical velocity of the load. This vertical load velocity was controlled using a modified angular isokinetic dynamometer, which produced linear isokinetic motion during a lift. A lumbar monitor was used to observe the position, velocity, and acceleration changes that occurred in the lumbar spine during the lifting task. The results indicate that under constant load velocity conditions, significant angular accelerations occur at the lumbar level. The nature of these accelerations was found to depend on several variables associated with a lifting task, such as the load velocity and the asymmetry of the lift. The physical significance of these results would be increased spinal loading above that which would be predicted using a static model.
Anthropometry of Seated Women during Pregnancy: Defining a Fetal Region for Crash Protection Research
Authors: Culver Clyde C. , Viano David C.
Published: July 2017

An anthropometric description was developed for the fetal region of women at three, six, and nine months of pregnancy. This involved superimposing a fetal ellipse on abdominal and pelvic ellipses of seated women from a previous study. The data were developed for women of 5th, 50th, and 95th percentile size. The ellipses identify body contact zones on the side and front which would interact with the fetal region in a crash. The new information provides spatial characteristics of pregnant women for the development of test dummies, accommodating restraints, and friendly interiors and for enhancing crash protection. This research addresses the 342 deaths of pregnant women estimated to occur annually in motor vehicle crashes.
Comprehension and Memory of Instruction Manual Warnings: Conspicuous Print and Pictorial Icons
Authors: Young Stephen L. , Wogalter Michael S.
Published: July 2017

Two experiments examined the effects of increasing the noticeability of instruction manual warnings on subsequent comprehension and memory performance. Participants read one of four instruction manuals for a gas-powered electric generator (Experiment 1) or a natural-gas oven (Experiment 2) on the assumption that they would later operate the equipment. The appearance of eight different warning messages in the manuals was altered in two ways: (1) the verbal messages were printed either in conspicuous print (larger text with color highlighting) or in plain print (same as the other text), and (2) either the verbal warning messages were accompanied by compatible pictorial icons or the icons were absent. Results showed that participants who received the conspicuous print, icons present manual better comprehended and recalled the verbal warning messages (Experiments 1 and 2) and better identified the semantic meaning of the icons (Experiment 1) than did participants who received the other three manuals. Implications for the design of instruction manual warnings are discussed.
Sources of Human Error in Data Entry Tasks Using Speech Input
Authors: Frankish Clive , Noyes Jan
Published: July 2017

Where speech recognition devices are used for entering data, some form of feedback is usually provided so that recognition errors can be detected and corrected. The present experiments were designed to investigate how the accuracy of data entry is influenced by the type of feedback used and by the structure of the error correction dialogue. Experiment 1 compared the effects of visual and spoken feedback delivered either after each item or at the end of the data string. With visual feedback, most failures to achieve correct data entry occurred when subjects failed to detect recognition errors. Spoken feedback was much more closely monitored, but with word-by-word feedback, subjects had difficulty in recovering from mis-recognitions in the error correction dialogue. Experiment 2 was designed to examine possible interactions between presentation and feedback modalities when data strings were entered from memory. Although there was some evidence of an interaction, the effects were small in relation to the much greater disruption of memory caused by correction of recognition errors in midentry. The implications of these findings for the design of feedback and error correction dialogues are discussed.
Inspection of Low-Level Radioactive Waste
Authors: Casey Steven M.
Published: July 2017

The accuracy of manual inspection of low-level radioactive waste (called dry active waste, or DAW) was determined in three studies conducted at two nuclear power plants. The project was conducted to determine the level of sorting accuracy in work settings given existing procedures, equipment, and technician characteristics. The research paradigm employed in each of the three studies included an unmodified waste stream of roughly 10 000 items and sorting by radioactive waste technicians using hand-held probes. Sorting performance was measured unobtrusively by intercepting the outflow from sorting stations and verifying the radioactivity of each piece of trash with a prototype semiautomated sorting table. In all, more than 30000 items of trash were examined, classified, counted, and verified. The results showed that between 1% and 19% of all items in each of the three DAW waste streams were contaminated at levels ≥100 corrected counts per minute. Sixty-two percent of the contaminated items in Study 1,87% of the contaminated items in Study 2, and 97% of the contaminated items in Study 3 were detected during inspection. False positive rates were very high in all three studies. The production rates and accuracy obtained on the semiautomated plastic scintillation sorting table used during the verification stages of this project greatly exceeded the rates for manual sorting.
Tracking Strategies and Cognitive Demands
Authors: Goettl Barry P.
Published: July 2017

The processing demands of two tracking strategies are investigated using an optimum-maximum procedure. Subjects performed two one-dimensional tracking tasks concurrently. Ten subjects employed a double-impulse strategy, and 10 subjects used a continuous strategy. On each task control dynamics were manipulated within subjects, as was the level of optimization. Results showed dual-task decrements but little performance trade-off. These results challenge but do not rule out a resource competition interpretation. Subjects employing the continuous strategy were more adversely affected by increased tracking order than were subjects using the double-impulse strategy. This finding suggests that the continuous strategy demands more central processing resources than does the double-impulse strategy. The implications of these results for workload analysis and dual-task methodology are discussed.
Improving Auditory Warning Design: Relationship between Warning Sound Parameters and Perceived Urgency
Authors: Edworthy Judy , Loxley Sarah , Dennis Ian
Published: July 2017

This paper presents an experimental study of the effects of individual sound parameters on perceived (psychoacoustic) urgency. Experimental Series 1 showed that fundamental frequency, harmonic series, amplitude envelope shape, and delayed harmonics all have clear and consistent effects on perceived urgency. Experimental Series 2 showed that temporal and melodic parameters such as speed, rhythm, pitch range, and melodic structure also have clear and consistent effects on perceived urgency. The final experiment tested a set of 13 auditory warnings generated by an application of the earlier experimental findings. The urgency rank ordering of this warning set was predicted, and the correlation between the predicted and the obtained order was highly significant. The results of these experiments have a widespread application in the improvement of existing auditory warning systems and the design of new systems, where the psychoacoustic and psychological appropriateness of warnings could be enhanced.
Effects of Instructional Strategy and Motion Presentation Conditions on the Acquisition and Transfer of Electromechanical Troubleshooting Skill
Authors: Swezey Robert W. , Perez Ray S. , Allen John A.
Published: July 2017

Three instructional strategy conditions and the presence or absence of visually presented motion during instruction were manipulated, and their effects on the acquisition and transfer of electromechanical troubleshooting performance were investigated. In this study use of visually presented motion during training (as opposed to static display presentation) was not found to enhance either maintenance performance or transfer on troubleshooting tasks. However, results indicated that subjects trained via a procedure-based training strategy performed more accurately, but slower, than did subjects whose training consisted of conceptual information concerning system structure and function for a reference performance task. When a transfer task was used as the criterion measure, results indicated that training that included conceptual information concerning a system's structure and/or function improved performance. Results thus suggested that some level of generic structure and functional knowledge is required for cross-domain transfer on cognitive troubleshooting tasks, and that this information should include both general procedures for troubleshooting and declarative information on the structure and function of the systems of interest.
Simulation-Based Instruction of Technical Skills
Authors: Towne Douglas M. , Munro Allen
Published: July 2017

A rapid intelligent tutoring development system ( RAPIDS) was developed to facilitate the production of interactive, real-time graphical device models for use in instructing the operation and maintenance of complex systems. The tools allowed subject matter experts to produce device models by creating instances of previously defined objects and positioning them in the emerging device model. These simulation authoring functions, as well as those associated with demonstrating procedures and functional effects on the completed model, required no previous programming experience or use of frame-based instructional languages. Three large simulations were developed in RAPIDS, each involving more than a dozen screen-sized sections. Seven small, single-view applications were developed to explore the range of applicability. Three workshops were conducted to train others in the use of the authoring tools. Participants learned to employ the authoring tools in three to four days and were able to produce small working device models on the fifth day.
Toward a Movement Dynamics Perspective on Dual-Task Performance
Authors: Swinnen Stephan P. , Walter Charles B.
Published: July 2017

The effect of practice on the parallel organization and control of discrete, asymmetrical bimanual movements was investigated. Subjects performed a flexion movement in the left limb together with a flexion-extension-flexion movement in the right limb. Two groups, one of which received kinematic information feedback, were instructed to produce the different patterns simultaneously. A third group performed each movement in isolation at all times, serving as the baseline condition. The degree of success in parallel action organization was assessed at the qualitative (or structural) and quantitative (or metrical) level of movement specification. Findings revealed that the bimanual groups displayed a tendency to synchronize the patterns of motor output, resulting in (mutual) interference. However, the provision of augmented kinematic information feedback resulted in more successful metrical and structural dissociation of the limb actions. The results are discussed in support of a movement dynamics perspective on motoric dual-task performance. The relevance of this approach for human factors is also emphasized.