bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of an Optical Aid on the Visual Fatigue and on the Performance of VDT Operators
Authors: Stuart Mark Alan
Published: January 2012

The main objective of this study was to investigate a method of reducing the amount of visual fatigue which is often associated with VDT usage. Specifically studied was the effect of the provision of refractive power on various indicants of visual fatigue (distant focus time, eye-blink rates, and visual acuity), visual-search performance on a computer, and evaluative responses on a questionnaire. Refractive power was provided with the use of nonprescription reading glass. Two different character sizes (4.8 and 5.8 mm) and two different viewing distances (508 and 666 mm) were also studied to determine if an increase in the visual angle of characters would result in significant improvements.

After analyzing the data with a repeated measures analysis of variance, it was determined that the use of the reading glasses resulted in significantly ( p < 0.05) lower: distant focus times and left-eye acuity measurements. There were no significant benefits on other measurements taken. The glasses resulted in fewer visual complaints on several questionnaire responses, but there was not a strong preference for the glasses. There were virtually no differences between the two different character sizes and viewing distances studied.

It is concluded that if the reading glasses are used under certain conditions (the user is nonastigmatic and has at least 20/20 vision - either corrected or uncorrected) then they may help reduce some of the visual fatigue associated with VDT usage for operators in the field.
Diagnosis of Low Back Injury Using Strength Measurement
Authors: Waikar Avinash M. , Schlegel Robert E.
Published: January 2012

A study was conducted to investigate the feasibility of using strength measurement as a diagnostic technique for assessing low back injuries involving symptomatic lumbar spine disease. The approach was to evaluate differences in the rates of strength build-up and in the variability of sustained lifting exertions performed by three groups of subjects. These groups included healthy subjects performing maximal exertions, healthy subjects performing submaximal exertions and symptomatic subjects with low back pain performing safe maximal exertions. The rate of strength build-up reliably distinguished between maximal and submaximal exertions while the ratio of within-trial variability to strength score differed significantly between the healthy and injured groups. Discriminant analysis was employed with partial success in distinguishing between the three groups using various derived measures of the force exertions.
The Biasing Effects of Product Familiarity on Consumers' Awareness of Hazard
Authors: Godfrey Sandra S. , Laughery Kenneth R.
Published: January 2012

Although toxic shock syndrome (TSS) and its connection to tampon use has been highly publicized, the extent of the average consumer's knowledge of the specific hazards involved is questionable. Women become familiar with this product and therefore may underrate its hazards and fail to notice warnings. A survey was conducted to determine women's awareness of the hazards of tampon use, their awareness of warnings about TSS, and their knowledge of the symptoms of TSS. They were not so likely to notice warnings on or in the tampon packages when they switched products as they were earlier. They were not well informed as to the symptoms of TSS, and many did not know that more absorbent tampons are more hazardous. The relationship of these results to the familiarity effect is discussed. Also, implementation by manufacturers of effective warnings on these products in order to enable women to use them safely is discussed and recommended.
Cockpit Automation Technology
Authors: Aretz Anthony J.
Published: January 2012

This paper presents a prototype methodology conceived by the United States Air Force to establish a baseline approach in the development of a new human factors crew station design methodology for emerging weapon systems. The goal of the project is to develop a structured human factors design methodology that can be used by designers to assess emerging technologies and relate them to system requirements and human performance characteristics so that the features of the resulting designs satisfy specific operational mission objectives.
The Effects of Aerial Perspective on Altitude Estimation
Authors: Patterson Michael J. , Rinalducci Edward J.
Published: January 2012

Recent interest in the importance of visual displays within specified flight simulations and scenarios has led to increased emphasis on the identification of pertinent cues within these displays. Through the identification of these cues and their usage in altitude estimation, more effective simulation and hence training programs can be developed.

The present explanatory study investigated the use of a psychophysical methodology in the evaluation of aerial perspective as a possible cue in altitude estimation. Specifically the effects of two levels of aerial perspective (present and reduced) and flight experience on estimations were examined. Based on the linear functions of log estimated vs. log actual altitude, differences were found between levels of flight experience in the aerial perspective-present condition.

Subjective responses suggest that individuals are aware of the presence/absence of haze conditions and this information influences their altitude estimations.
Pre-Occupant Departure Hvac Shutdown: A Strategy for Energy Conservation
Authors: Rohles Frederick H. , Laviana Joseph , Runbai Wei
Published: January 2012

The human response to the thermal environment depends in part on the temporal nature of the exposure. One aspect of the temporal dimension includes ramps or drifts that are brought about when the heating or cooling system is turned off. When this occurs, the shape of the drift depends upon the outside temperature and wind velocity, the solar load; the building shell, the location of the occupant and the indoor thermal load including the occupant density and machinery. The Honeywell Corporation in Arlington, Illinois has developed a model that will predict the temperature drifts at various locations within the occupied space when the HVAC system is shutdown. This regulation of the office temperature before workers leave for the day represents an energy saving strategy. The purpose of this study was to examine the comfort response of humans when exposed to drifts that began 0.5 h and 1.0 h before the normal departure of the employees. Drifts were examined at 4 locations: interior, west side and north side; a control “no-drift” condition was also used. The results showed for the 1.0 h drift that no source of variance was significant for the Thermal Comfort votes. Location, however was significant for the Thermal Sensation votes. For the 0.5 h drift the only significant source of variance was the location x sex interaction for the Thermal Comfort votes. A discussion of the implication of the results as an energy conservation strategy is provided.
Degradation of Performance Due to Sleep Deprivation: A Field Test
Authors: Ball C. , Funk T. , Noonan D. , Velasquez J. , Konz S.
Published: January 2012

During a 72 h field test, two groups of elite, “ranger type” soldiers were evaluted five times (during the first 8 h, after 30 h of continuous field duty, after a rest period, after 30 more h of continuous field duty, and after a second rest). One group (7 soldiers) received two rests of 3 h each. The second group (6 soldiers) received two rests of 6 h each. Five military tasks (map reading, decoding messages, vehicle/aircraft recognition, assembly and disassembly of the M-16 rifle, and preparation of an AN/PRC radio for operation) were used. These tasks were considered by the commander to be representative of duties that the soldiers would do and were considered to be completely familiar to the soldiers. In addition, a peg into pegboard task and a subjective evaluation of fatigue questionnaire were given.

There was no significant effect of time or difference between the two groups. The soldiers completed these tasks of short duration (less than 3 min) without decreasing performance—even after extended periods of sleep loss. These performance results occurred even though subjectively the soldiers reported they were tired.
The Optimum Presentation of Cognitive Training during a Flight Training Program
Authors: Smith Bruce A.
Published: January 2012

Four groups of subjects (N = 8 in each group) were presented training, based on the cognitive aspects of a basic flight maneuver, at different times during the acquisition of the motor skills needed to perform that maneuver. Results indicate that the performance of the group that received extensive cognitive training prior to attempting the associated motor skills was significantly better (p<.05) than the groups that received the same cognitive training interspersed during the initial learning of the motor skills. This was true even when the interspersed training was preceded by extensive cognitive pretraining. Results also show that cognitive training interspersed with motor skill learning produced a deterioration in performance as the performance of the two groups receiving the training was below that of the control group which received no cognitive training whatsoever. Transfer of training to a similar maneuver indicated that the groups that were initially trained using extensive cognitive pretraining performed significantly better than the groups that received only interspersed cognitive training and the control group.
A Control Model: An Alternative Interpretation of Fitts' Law
Authors: Connelly Edward M.
Published: January 2012

Fitts' law has been universally cited as an index of difficulty or predictor of movement time (MT) for rapid aiming tasks since it was first published in 1954 (Fitts 1954). Many researchers report a remarkable correlation of Fitts' law and the observed movement times in aiming tasks. Other researchers report discrepancies, however, between observed movement time and the law, especially at low and high movement times, which correspond, respectively, to short movements to a large target, and long movements to a small target. These discrepancies suggest that while the law predicts MT well for some human motions, the true basis for the law may not be known, and, as a consequence, that there may exist conditions where its application is appropriate and yet others where different laws should be used.

Fitts suggested the law as a model of the rate-limit of human information processing and movement. But this rate-limit model is not the only interpretation possible. Rapid movement of the hand to a target can be modeled from a different view-point: namely, as a control system. This paper gives the analytical results for several models: a first order model where it is assumed that the hand velocity can be directly controlled, and a second order model where it is assumed that the hand acceleration can be directly controlled. The results show that the first and second order models with the linear control-law produce a MT function with the exact form of the Fitts' law, and yet it has nothing to do with information theory.
Ferscnalot Differences as a Moderator of Menial Hckkload Behavior: Mental Workload Performance and Strain Reactions as a Function of Cognitive Complexity
Authors: Robertson Michelle M.
Published: January 2012

Two groups were pre-selected on the basis of high abstraction or concreteness scores on a test for the personality trait of cognitive complexity. The groups of participants undertook four sequential phases of a fire command, computer-generated, mental workload task. Multiple measures of the mental workload were taken consisting of primary task performance, subjective estimate of relative task difficulty, and physiological response as reflected in the level of sinus arrhythmia. Abstract individuals successfully completed the initial phase of the task, judged to be intermediate in workload, and the overall task in significantly fewer trials than did the concrete individuals. The abstract group also took significantly less time to complete the task during the initial acquisition phase, a trend that was affirmed in the overall time to complete the entire task. Concrete participants perceived the task to be most difficult during the initial phase, whereas the abstract group's subjective evaluation varied directly with the progressive loading of the task. Differences in the scores of sinus arrhythmia for the two groups were shown in the expected direction but failed to reach significance. This study indicates that personality, as reflected in the level of cognitive complexity, is an important moderator of human behavior in the performance of mental workload tasks.
Search Performance as a Function of Depth of Processing and Scrolling Rate
Authors: Alvarez Maria G. , Murray J. Thomas , Hakkinen Markku T.
Published: January 2012

Most investigations of task performance as a function of the scrolling rate have focused on display characteristics (e.g. character density and line spacing) as the major class of covariats. However, a more important class of variables pertain to the user's goal or task that caused him to envoke the scrolling function. Accordingly, the focus of the present study is the impact various scrolling rates have on performance as the complexity of the user's task is varied.

The complexity of a search task was varied over two levels on a Depth of Processing dimension (Cralk & Lockhart 1972) for each of three line-by-line scrolling rate conditions as well as for a paging condition in which the contents of the screen was advanced 23 lines of the 24 line display. In the semantic search condition, (high task complexity) users searched text displayed on a CRT for a word that is a member of a pre-designated category such as an animal name. This task requires that the user process each word in the display on a semantic level to determine whether or not it is a member of the target category. Also, it is argued that the semantic search task, which is less complex than a reading task, is representative of tasks for which users typically search a display. In the feature search condition, (low task complexity) users searched a CRT display for an exact match to a pre-designated target word. For this task the user need only process each word in the display to the visual feature level to determine whether or not it is the target word.

Assuming that more cognitive processing time is required for the semantic search task than the feature search task, it was expected that the optimal scrolling rate for the visual search task would be faster than that obtained for the semantic search task. The preliminary results confirmed this expectation and also indicated that the paging conditon produced better performance than any of the line-by-line scrolling conditions.
Human Factors and Synthetic Speech
Authors: Thomas John C. , Rosson Mary Beth , Chodorow Martin
Published: January 2012

Recent advances in linguistics, speech science, psychology, and especially in computers have made unlimited text-to-speech conversion systems a practical reality. However, the use of audio output from a computer poses special problems in ergonomics, most of which have not been dealt with in the literature. To provide high quality speech synthesis in a useful and usable system requires research in several areas (prototype applications, general design issues for touch-tone phone/speech interfaces, and improving the speech signal itself). In this paper, we review recent work in our laboratory in each of these areas. We close with a discussion of the implications of our work to date for the development and use of speech synthesis.
Ergonomic Skills Training: Discussion of Methods Used to Improve Skill and Comfort Levels of Workers Using Video Display Terminals
Authors: Joyce Marilyn S.
Published: January 2012

Ergonomic Skills Training is the new way of enabling workers to take responsibility for their own comfort and productivity in VDT environments. After receiving Ergonomic Skills Training, VDT users have demonstrated productivity increases, and error decreases, in a variety of applications. In addition, they have reported dramatic improvement in their health/comfort levels. The training involves the following:

Short-term Memory Skills in both visual and auditory perception which serve to reduce keying and proofing errors.

Physical exercises to be performed at the workstation throughout the day to prevent and/or reduce fatigue, eyestrain, muscular pain.

Individual workstation adjustments to enable workers to adapt basic ergonomic principles to existing work environments and thus enhance work flow and personal comfort.

This paper is a description of the training methods used and the results reported by trainers and clients.
Research Issues in Teleoperator Systems
Authors: Pepper R. L. , Hightower J. D.
Published: January 2012

This paper briefly describes the Naval Ocean Systems Center's newly initiated program in teleoperator technology, as well as prior research conducted by our perceptual sciences group. The general objective of this program is to provide the technology base required to produce tele-operator systems which will be capable of performing man-like tasks in areas too hazardous or too costly for human habitation. Our approach has been guided by the conviction that substantial improvements in remote task peformance result when operators are provided a heightened sense of “remote presence”. We have pursued the development of a generic anthropomorphic teleoperator which will employ tools, vehicles and systems that currently exist for human use. For several years, we have been engaged in a program of research aimed at developing a scientific understanding of the dynamic interactions which occur between the human operator and the sensors, controls and displays that constitute the viewing and manipulator systems of teleoperators. The results of our past and current research studies are briefly described, along with a program plan for increasing understanding of man's role in teleoperator technology.
The Test of a Task Re-Design
Authors: Schmidt John K. , Petree Barry L.
Published: January 2012

Industrial work settings are often poorly designed from a Human Factors perspective and eventually require costly modification. In light of the expense, it seems reasonable to test planned re-designs to ensure that they rectify problems found in the original layout and do not create new ones. The present study involved the use of a layout mock-up to simulate both original and re-design conditions for a filter change-out operation that was causing a large number of neck, back and shoulder injuries. The results indicated that the re-design was effective in increasing performance to meet task criteria and in reducing biomechanical stress.
A Methodology for Work Chair Assessment
Authors: Christensen C , Casali J. G. , Kroemer K. H. E.
Published: January 2012

A large segment of the office work force in the United States spends a majority of their work day seated in stationary chairs. Problems with postural fatigue and related maladies are commonly associated with the neck, arms, shoulders, as well as with different portions of the back.

This study was conducted in an effort to determine whether several metrics for general posture and comfort evaluation were viable specifically for work chair evaluation. These techniques were a modification of a posture measurement technique developed by Corlett, Madeley and Manenica (1979) known as Posture Targeting. In addition, three subjective rating scales were used.

MANOVAs were performed on the data. Both task-type and chair-type were found to significantly influence the posture and subjective responses of the subjects in the study.
Grasp Fatigue as a Function of Handle Size and Shape
Authors: Natarajan Joann , Cochran David J. , Riley Michael W.
Published: January 2012

This study investigated the influence of handle characteristics on fatigue of the gripping muscles while doing a slicing task as in using a knife in cutting meat. Subjects actually cut cylinders of modeling clay as a simulated meat-cutting task. Immediately after completing the cutting task the time to fatigue for the grasp muscles was estimated using the electromyographical technique developed by Petrofsky and Lind (1980). The handles evaluated were all rectangular ones with cross-sectional height to width ratios from 1:1.25 to 1:2. Each ratio was tested in four sizes. No significant differences in time to fatigue were found for the different handles. Time to fatigue was, however, significantly correlated with six anthropometric measures.
Angular Subtense Requirements for Colored CRT Symbology
Authors: Post David L. , Sheibenberger Denise
Published: January 2012

Little is known regarding angular subtense requirements for colored CRT symbology. In the present experiment, small colored symbols were displayed against a black background and subjects adjusted their size to meet various legibility criteria. The results show that color had relatively little influence on legibility and major impact on hue recognition and that the interpretation of color's effects must weigh some unique characteristics of CRT technology.
Changes in Knowledge Representations of Computer Systems with Experience
Authors: Kay Dana S. , Black John B.
Published: January 2012

This study examined the changes in the knowledge representations of text-editing commands as experience increases. Novices appear to organize the commands by their definitions, whereas experts use both command definitions and command sequence configurations to organize the commands. Thus, it appears that declarative knowledge is the first type of knowledge to be acquired in learning text-editing commands. At a more general level, experts and novices both organized their commands along three general dimensions, but the third dimension was different for the two groups. The results of this study, in conjunction with previous computer system studies, suggests an incremental model of the acquisition of computer-related knowledge in which there are changes in both the content and the representation of the knowledge.
The Effects of Long Term VDT Usage on Task Performance
Authors: Lewis David A.
Published: January 2012

In response to a request from the US Patent and Trademark Office, a simple experiment was conducted to help evaluate the effects of long term exposure to video display terminals (VDTs) on worker performance. This test was conducted with 16 subjects, students at the University of Puerto Rico. The results indicate that performance on a short term memory recall experiment significantly deteriorates (alpha = .05) after slightly more than one hour of continuous viewing. Because of complaints of headaches and eye fatigue, the experiment was discontinued after this period of time.
A Method for Systematic Workload Estimation (SWE)
Authors: Burford Charles L. , Ramsey Jerry D. , Tayyari Fariborz , Lee Chin Hyong , Stepp Robert G.
Published: January 2012

Using the information available in the literature, a coding method has been developed which reduces the difficulties associated with the estimation of metabolic workloads. A person can be trained to use the system with minimum time and effort. The only equipment required are worksheets, watch and a clip board. Systematic Workload Estimation (SWE) can be applied to the activities with constant or changing paces. Its validity has been examined by coding and calculating the metabolic costs of numerous activities and comparing the results with the values given in published tables.
Simulators Used in Maintenance Training: A Survey
Authors: Carroll Robert J.
Published: January 2012

Simulators are becoming an increasingly prevalent component of maintenance training curricula in the military services. The types of simulators in use and their training functions vary widely, from electronic logic boards that provide troubleshooting exercises to full scale mockups that allow students to identify component locations and practice operational checks.

A survey of over 25 military and civilian maintenance training simulators was conducted to identify the types of devices currently in use, the role they play in the training environment, student/instructor attitudes toward the devices, and other factors which impact the cost/training effectiveness of maintenance simulators. Personnel surveyed included students, instructors, course managers, simulator operators, and maintenance personnel. This paper summarizes the findings of the survey, and discusses the results in light of optimizing the utilization of simulators in maintenance training.
Discussion: Information-Processing Models
Authors: O'Hare John J.
Published: January 2012

The foregoing papers are joined, yet divided, by their approaches to the concept of interface, and express those differences in the choice of technique of measurement and the emphasis on distinct cognitive processes. The interface definitions include: (a) the characteristics at the machine surface and this is demonstrated in the Bennett study on accessing data bases and Boebm-Davis' work with programming methodologies; (b) the medium or task environment between the operator and the machine such as Parasuraman's focus on signal detection models; (c) a software module that is adaptable or responsive to the operator that is introduced by Howard et al. in the image processing study; and (d) the processing elements embedded within the operator as is characterized in Robertson's research on text-editing. It is evident that each of these approaches is a facet of human-computer interaction and integrative models are required before adequate understanding of human performance on this task can be realized. Computer architecture has been highly influential in suggesting structural elements that underlie the information-processing models which are often invoked to explain the results of human-computer interaction studies. It would appear that those models have run their course. Another perspective, derived from software programming concepts, has had a fresh impact on the interpretation of human-computer performance; in the main, those concepts that have been adopted are related to applications software and these notions are present in some of the foregoing reports. The next step in programming concepts is the emergence of modules of user-interface systems that will link hardware and application-software systems. At least one theorist (J.A. Fodor) has developed an argument that that suggests the characteristics of the human-processing elements that would comprise such a module; however, this development is not clearly anticipated in these papers.
Setting Acceptable Levels of Safety for the National Airspace System
Authors: Busch Allen C. , Colamosca Brian F.
Published: January 2012

The FAA is engaged in a major effort to safely reduce the vertical separation standard to 1,000 feet between aircraft flying above 29,000 feet and to develop system performance requirements which, if met, will ensure safe operation of the National Airspace System. To accomplish this we are proposing an overall program structure of defining risk/safety criteria, a risk assessment program, and a risk management program. Included in this effort is an extensive in situ data collection effort. Hopefully, the conclusion of this effort will result in providing to management the quantitative decision tools and information necessary to (1) make the decision for the safe reduction of the vertical separation standard and (2) to implement changes to the National Airspace System to support new separation procedures.
Computer-Based Activities for Teaching Engineering Psychology Concepts
Authors: Reed Paul
Published: January 2012

A set of interactive microcomputer-based exercises has been developed to introduce students to some basic concepts in engineering psychology as well as general issues in the field of behavioral science. Students interact with the program through a series of prompts and menus that allow them to receive on-line instructions, specify certain experimental parameters, participate as subjects in the computer-run experiment, and obtain graphical summaries and statistical analyses of their data. The programs are designed for students with little or no previous computer experience and run on a Apple II or 11+ computer with 64K and a disk drive.
Assessment of SWAT Accuracy
Authors: Revesman Mark E. , Rokicki Stephen M.
Published: January 2012

Recently, the Subjective Workload Assessment Technique (SWAT) has become a popular tool for assessing mental workload. SWAT attempts to estimate an individual's internal representation of mental workload from a rank ordering of combinations of mental workload factors. This paper presents an experiment in which these internal values were simulated on a computer. Conjoint analysis was performed on rank orders produced from the internal values with and without noise added. Results indicated that conjoint analysis was able to accurately estimate the “true” rankings and values, even when noise was present. In addition, linear regression was found to be a poor estimator of the “true” values, while a simpler technique, rank summing, was found to be as accurate an estimator as conjoint analysis.
Workload Measurement in System Design and Evaluation
Authors: Eggemeier F. Thomas , Shingledecker Clark A. , Crabtree Mark S.
Published: January 2012

Because of its central role in system development, workload measurement has been extensively researched. These efforts have produced a variety of workload assessment techniques, many of which can be classified as either subjective, physiological, or behavioral measures. These categories of measures can vary along several dimensions that can be used as criteria in selection of a technique for a particular application. The proposed selection criteria include the sensitivity, diagnosticity, and intrusiveness associated with a technique. Different stages of system design can require techniques that differ on the noted dimensions. Since no technique is capable of meeting all of the applicable criteria, a comprehensive approach to workload assessment will require a battery of subjective, physiological, and behavioral measures. Future research dealing with comparative evaluation of the various assessment techniques along the noted dimensions will be required in order to refine workload metric selection criteria.
Torque Characteristics for a Consumer Sample
Authors: Kreifeldt John G.
Published: January 2012

A series of experiments were conducted to determine the maximum amount of torque that males and females could apply by hand to knobs of commercial products.

The purpose of the experiments was to provide data suitable for the safe design and testing of a common household item. Investigations had revealed that in some instances users may have turned a knob past a point where the item became in effect a “time bomb” even though the item had been purportedly designed to withstand the torque required to do this. Further, the ability of the design to withstand the torques required to do this may also have been inadvertently tested in the quality control and inspection station of the manufacturer.

Literature clearly indicates that the amount of torque that may be exerted depends on factors of knob design such as its radius, geometry, etc. Because the literature did not provide data precise enough for the present purposes a series of experiments were made to answer the specific questions.

For the knob in question, and as an example of the results obtained, it was found that 14 males could exert an average of 36 inch-pounds (standard deviation of 7.2 inch-pounds) to the knob with their unaided hands and for a one time maximal effort.

For the manufacturer's testing procedure in which women testers were equipped with a large radius handle tool with which to turn the knob, it was found that women could exert a one time maximum torque of 37.00 inch-lbs with the tool inserted into the knob. However, in as much as the quality control testers need to exert a torque on the order of once per minute or two, it was more realistic to measure the sustainable level that could be achieved.

As an indication of what this might have been, the women were requested to exert their maximum torque ten times consecutively with a minute between efforts. The results showed that the torque level fell to 30.64 inch-lbs by the tenth trial and that furthermore the decline in torque was well fitted (correlation of 0.95) by a power function.
Improving Motorcyclists' Braking Performance: The Integrated Brake System
Authors: Mortimer Rudolf G.
Published: January 2012

Two motorcycles were used in these tests, each of which could be operated in both integrated and separated braking modes. The motorcycles had engine displacements of 400 cc and 1100 cc. The braking test was performed by 24 riders, nine of whom were instructors in motorcycle rider courses.

It was found that, on both dry and wet pavements, decelerations were significantly greater in the integrated braking mode than the separated mode when foot brakes alone were used and there were no significant differences in the frequencies with which wheels were locked between these modes. However, there was a consistent trend of fewer lockups in the integrated mode. When both brakes were used on the larger motorcycle significantly greater mean deceleration was attained in the integrated than separated mode but this was accompanied by significantly more wheel lockups in the integrated mode.

The results indicated a significant advantage in braking performance with integrated brakes for the motorcycle rider course instructors and the other riders. This advantage could be expected to reduce stopping distances of motorcycles and, thus, their involvement in accidents.
Pro-Swat Applied to Advanced Helicopter Crewstation Concepts
Authors: Kuperman Gilbert G.
Published: January 2012

The Subjective Workload Assessment Technique was applied projectively (Pro-SWAT) to the prediction of workload to be expected in a single-pilot, advanced scout/attack helicopter weapon system. A composite mission scenario was created. Five configurations of the pilot/vehicle interface were synthesized, each based on some form of a virtual panoramic display (VPD). They were assessed at each of six segments extracted from the mission scenario. An analysis of variance, with predicted workload as the dependent measure, found highly significant differences between both mission segments and VPD concepts (p < 0.01).
Learning and Performance in an Air Refueling Part-Task Trainer: Preliminary Data Analysis
Authors: Stewart John E.
Published: January 2012

This paper recounts ongoing attempts to develop a system of performance measures (PM's) for the Air Refueling Part-Task Trainers which will be used by the Military Airlift Command (MAC) for currency training of C-5/C-141 aircrews. The database at present includes over 30,000 observations on a total of 22 student pilots and 3 instructor pilots. Subjects were observed during their participation in the ARPTT course at Boeing-Kent, Washington. Representative multivariate analyses were conducted on subsamples of the data with movement of the simulated receiver aircraft along the roll, pitch and yaw axes and relative movement forward-aft, azimuth and vertical comprising the independent variables, and time spent in the refueling envelope the dependent.

The most important predictor was movement about the fore-aft axis relative to the tanker. No others were significant. The implications of these and related findings as to aircrew training and PM development are discussed.
Chess Model Applications to Study Improvements in Driver's Night Visual Performance
Authors: Bhise Vivek D.
Published: January 2012

This paper presents the results of several studies conducted by using the Ford Comprehensive Headlamp Environment Systems Simulation (CHESS) model (1,2). This model provides a much broader, more comprehensive and more economical computerized method for measuring headlighting performance than the traditional seeing distance field tests. The model was developed from an extensive program including nighttime field tests, traffic surveys and analysis and applications of earlier research work.

The model was simulated to study how various improvements in drivers night visibility can be made by altering characteristics related to vehicle headlamps, roadways and driver behavior. Some of the variables used in these sensitivity analyses included changes in headlamp beam, headlamp aim, road delineation practices, traffic velocities, roadway lighting practices, and night travel exposure.
Describing Truck Driver Eye, Head, Stomach, Knee and Seat Locations in Heavy Truck Space
Authors: Philippart Nancy , Stanick James , Kuechenmeister Timothy
Published: January 2012

Photogram metric data collected in the SAE U.S. Truck Driver Anthropometric and Workspace Study were used to develop functional workspace models to describe where truck driver eyes, heads, stomachs, knees and seats were located in vehicle space. These models describe the probabilistic location in heavy truck space of the body landmarks of populations of truck drivers with various percentages of males and females as a function of vehicle packaging parameters. These models can be used to determine visual accommodation, head clearances, clearance between the stomach and steering wheel, knee clearance to the instrument panel surface and the location and amount of seat travel necessary to accommodate certain percentages of users with a certain cab design. Models were developed for truck driver populations with 50%/50%, 75%/25%, 90%/10% and 95%/5% male to female ratios. This distribution of models allows the designer to determine accommodation for several potential user groups.
Integration of Principles of Human Factors into an Undergraduate Computer Technology Curriculum: A Case Study
Authors: Hoffman Susan C.
Published: January 2012

undergraduate university curriculums in computer technology are structured to provide students with a maximum exposure to programming languages, data structures, and elements of system design. Current textbooks fail to provide adequate discussions and examples of programs which demonstrate good human factors. The purpose of this study was to determine if concepts and techniques for designing human computer interfaces can be integrated within the existing courses in the undergraduate curriculum in computer technology. A class in applications programming using Pascal was given a long-term assignment to design an interactive program for an untrained user. This assignment was then repeated following exposure to human factors guidelines. The class showed significant improvements in the design of the user interface.
Biomechanics and Work Physiology in Underground Mining
Authors: Selan J.L. , Ayoub M.M. , Smith J.L. , Peay J.
Published: January 2012

A biomechanical and work physiology study in underground mining was conducted. Anthropometric, isometric strength, and physical work capacity (PWC) data were collected. Female miners were significantly heavier and larger in circumferential measurements than comparison groups (males did not differ from other groups in terms of anthropometry). Underground miners were significantly stronger than comparison groups, and were rated low in terms of PWC. Energy expenditure measurements were made on 35 underground mining tasks; the majority falling under the categories of moderate to heavy work. Postural stresses were assessed using a modified version of the Ovako Working Posture Analysis System (OWAS; developed by Karhu, et al. 1977). Several tasks appeared to cause substantial postural stress. Postural stress was correlated significantly with physiological demand. Recommendations based on the findings of the study included: increased use of powered equipment in place of manual labor for several tasks, modifications to existing equipment designs, and modifications to the work clothing design standards developed by Caddel, et al. (1981) for low coal miners.
Effects of Thermal Stress and Chemical Protective Clothing on Speech Intelligibility
Authors: Johnson Richard F. , Sleeper Lynn A.
Published: January 2012

In order to protect himself in a chemically contaminated environment, the combat soldier must wear a special jacket, trousers, overboots, rubber gloves, and a gas mask with hood. This clothing system was investigated for its impact upon the soldier's ability to understand human speech in a neutral environment and in a hot-humid environment. The results of this study indicated that, compared to control conditions, the chemical protective clothing has a detrimental effect on the ability to hear human speech and that this decrement is most severe when the chemical protective clothing is worn under hot conditions for extended periods of time.
VDT Operator Pupil Diameter Changes, Accommodation Changes and Subjective Comfort/Discomfort Score Changes over a Working Day
Authors: Zwahlen Helmut T. , Hartmann Andrea L.
Published: January 2012

Pupil diameter, accommodation and subjective comfort/discomfort were measured at certain times during the working day. Six subjects, all experienced typists, were used and worked two full days in a VDT workstation using two different data presentations, i.e. hard copy-screen and split screen, and a data entry and a file maintenance/editing task. An Applied Science Laboratory 1998 computer controlled eye monitor system was used to collect and analyze the pupil diameter data and the eye scanning data. A field laser optometer was used to measure the accommodative state of the subjects' lenses for a viewing distance of 6m (.17 diopters) before and immediately after each work session.

The results of this study indicate that neither the pupil diameter changes nor the accommodation changes reveal any consistent pattern which would enable one to predict reliably the actual mental workload, general fatigue, ocular discomfort or fatigue of VDT operators. On the whole the changes in accommodation over three hours of VDT work (near-visual task) follow the trend to a slightly more myopic vision for a distant 6m target. But these changes are relatively small and are accompanied by a rather large variability. The scores for the nine visual comfort/discomfort questions were rather low when compared to some of the musculoskeletal comfort/discomfort questions. Also, the rest breaks and the lunch break did produce rather small and not as consistent decreases in the ocular comfort/discomfort scores when compared with the effects on some of the musculoskeletal comfort/discomfort scores. Correlations between accommodation and some of the visual comfort/discomfort scores were examined to see how reliable the changes in accommodation measured with the field laser optometer were in predicting visual problems such as “hard to see sharply”. None of the correlations were statistically significant.
Behavioral Effectiveness of Warnings
Authors: Wogalter Michael S. , Fontenelle Gail A. , Laughery Kenneth R.
Published: January 2012

A paradigm was developed to examine the effectiveness of warnings in a laboratory task. A task was presented to subjects as one examining how people perform a basic chemistry demonstration. Experiment 1 examined the effects of two locations of the warning (before and after instructions) and two different signal word presentations (WARNING and Note). An additional condition with no warning or signal word served as a control. No effects were found on time or accuracy. However, compliance (use of mask and gloves) was affected by the inclusion of the warning as well as by its location. Greatest compliance occurred when the warning was placed prior to the instructions. Experiment 2 replicated the effect of location. The addition of a printed statement placed before the instructions (with warning at the end) to read through the instructions before beginning produced intermediate compliance that was not significantly different from the warning beginning and end conditions. Observation revealed that when the warning message was at the end of the instructions subjects complied only when they saw the warning message before starting the task. These results indicate that if warnings are placed in front of instructions the consumer is more likely to read and comply.
Quantifying the Subjective Evaluation of Occupied Space
Authors: Rohles F. H. , Laviana J. E.
Published: January 2012

The subjective human response to occupied space involves the measurement of affectivity. The measurement of the human affective state (i.e., how one feels or how some feature of the environment feels to the individual) tends to be arbitrary and dependent upon the bias of the investigator. Almost universally, the rating scale is selected to accomplish the measurement. Recent advances in rating scale development have moved the measurement of affectivity out of a purely arbitrary domain and into a more quantifiable modality. In this paper four scaling techniques and representative rating scales are presented for use in assessing the subjective human response to the environment.
Assessment of Task Proficiency in Air Force OJT
Authors: Warm Ronnie E.
Published: January 2012

An OJT task proficiency assessment system was developed and tried out in the Air Force OJT environment. The Task Evaluation Form system includes development procedures which when applied to a specific task allow Subject Matter Experts (SMEs) to generate evaluation instruments. The resulting instruments, called Task Evaluation Forms, accurately and completely depict the critical aspects of task performance. The Task Evaluation Forms can be used by OJT supervisors to detect errors in task performance and derive end scores and pass/fail decisions which reflect observed performance.
Physical Stress Reduction of Microscope Operators
Authors: Lee Kwan S. , Humphreys Linda A.
Published: January 2012

This study investigated the difference in the musculoskeletal stress-of microscopists between working in an ergonomically designed work station and working in a non-ergonomic station with physical exercises during their breaks. Five subjects worked an eight hour day in both work stations. The subjects' stress was measured subjectively (questionnaires) and objectively with electromyograms (EMG). The subjective questionnaires showed greater back stress in the non-ergonomic station but little difference between the stations for the other body sites. Although there was little difference in the number and severity of the complaints during the experiment, 80 percent of the subjects preferred the ergonomic station. The EMG results showed greater back and right shoulder stresses when working in the non-ergonomic station (F test with p < .05).
Development of an Overexertion Injury Surveillance System
Authors: Herrin Gary D. , Anderson Charles K. , Jaraiedi Majid
Published: January 2012

The frequency and severity of occupational injuries have been recognized as a major health problem within many industries for a long time. Conventional injury/illness reporting systems such as OSHA, Worman's Compensation, etc., offer no guidance for the concerned professional to identify root causes of these injuries or suggest ways to minimize consequences. The study reported on injuries at the dispensary visit level which would permit incidents to be correlated with physical job stresses across five industries. This paper compares the experiences between and within plants and shows that minor injury experiences can be used to predict more severe cases.