bluuebunny/crossref_metadata_2025 huggingface dataset:
Gender Differences in the Strain Response to Job Demand
Authors: McCright Paul R.
Published: January 2009

In a study of the effects of variations in the levels of job demand on self-reported levels of job-related strain, an unanticipated gender differential was found. Higher levels of job demand were hypothesized to lead to higher levels of job-related strain. No differential effect due to gender was anticipated. Subjects in the high demand condition reported significantly more job-related strain than did subjects in the low demand condition. However, when an analysis of covariance was performed, gender showed an unexpected interaction effect with demand. Females experienced lower levels of strain in the low demand condition than did males. In the high demand condition, females experienced higher levels of strain than did males. This indicates that women were more sensitive to demand variations than men. This gender difference suggests that assignment of workers to certain positions based on gender may reduce overall levels of job-related strain.
Current Developments in Research on Air Force Pilot Characteristics
Authors: Siem Frederick M.
Published: January 2009

A personality inventory was given to 509 USAF pilot candidates. The items were combined into five measures, two of which differentiated training successes from failures; graduates demonstrated higher self-confidence and less dogmatism. As an alternative approach to examining simple relationships between personality characteristics and training outcomes, personality profiles were examined as predictors of performance criteria. The value of this apporach was demonstrated by better discrimination of training graduates from non-graduates. The implication of these results are discussed, as are plans for other research projects designed to replicate and extend the findings from the current study.
A Gender Profile: U.S. General Aviation Pilot-Error Accidents 1982–1985
Authors: Vail Gayle J.
Published: January 2009

Women in aviation are having an impact on pilot safety records — a beneficial one. Evidence has shown that they are the safer of the genders while flying as Pilot-In-Command in General Aviation Flying.

Data was analyzed from the NTSB files for the year 1982–1985. The results found a positive gender factor for females in number, type, and cause of pilot-error related accidents.
Estimation of Duration and Mental Workload at Differing Times of Day by Males and Females
Authors: Hancock P.A. , Rodenburg G.J. , Mathews W.D. , Vercruyssen M.
Published: January 2009

Two experiments are reported which investigated whether male and female operator duration estimation and subjective workload followed conventional circadian fluctuation. In the first experiment, twenty-four subjects performed a filled time-estimation task in a constant blacked-out, noise-reduced environment at 0800, 1200, 1600, and 2000h. In the second experiment, twelve subjects performed an unfilled time estimation task in similar conditions at 0900, 1400, and 1900h. At the termination of all experimental sessions, participants completed the NASA TLX workload assessment questionnaire as a measure of perceived mental workload. Results indicated that while physiological response followed an expected pattern, estimations of duration and subjective perception of workload showed no significant effects for time-of-day. In each of the experiments, however, there were significant differences in durational estimates and mental workload response depending upon the gender of the participant. Results are taken to support the assertion that subjective workload is responsive largely to task-related factors and indicates the important differences that may be expected due to operator gender.
Functional Models of Complex Human Performance: Application to the Assessment of Pilot Performance
Authors: Nelson William R.
Published: January 2009

A method has been developed for formulating integrated models of complex human and machine performance. The functional models can be used to model human tasks, measure human performance, identify problem solving strategies, estimate human error probabilities, define training requirements, investigate accidents, and design decision aids for complex cognitive tasks. This paper summarizes the application of the functional modeling technique to the collection and analysis of data from an experiment designed to assess pilot performance while responding to malfunctions.
Gender Differences in Criterion Task Set Performance and Subjective Ratings
Authors: Schlegel Betina , Schlegel Robert E. , Gilliland Kirby
Published: January 2009

This paper summarizes gender differences in performing various elements of the Criterion Task Set. Performance data and Subjective Workload Assessment Technique ratings were analyzed for 28 men and 28 women who participated in a large-scale CTS validation study. In general, women tended to perform slightly better than men on the majority of tasks. In particular, performance by women was better on Grammatical Reasoning, Linguistic Processing, Mathematical Processing, and Memory Search. Response times on Probability Monitoring were faster for women but at the expense of a greater number of False Alarms. Men performed better only on the high level of Continuous Recall and the medium level of Unstable Tracking. Women tended to give lower subjective ratings than men to those tasks with a high memory component and gave higher ratings than men to those tasks involving input/output and spatial elements.
Overview: The Use of Think Aloud Verbal Protocols for the Identification of Mental Models
Authors: Blackman Harold S.
Published: January 2009

Results regarding the use of protocol analysis techniques are presented to show how they may improve the models identified through other knowledge engineering techniques and how these models may then be used to improve performance through training. Data from two experiments are presented and discussed.
Slope-Controlled Performance Testing
Authors: Jones Marshall B.
Published: January 2009

Cognitive-ability tests, though promising in other respects, generally show pronounced practice effects and have weak test-retest reliabilities. One reason for the low reliabilities appears to be that practice effects themselves vary from individual to individual, so that subjects differ not only in the levels at which they are performing when testing ends but also in the slopes leading up to those levels. Since slope of the performance curve late in practice has been shown to affect performance at reacquisition (retest), uncontrolled variation in slope may lower test-retest reliability. A possible approach to this problem is experimentally to control slope during testing so that all subjects are improving at roughly the same rates when testing ends. The expected effect is that, with inter-subject differences in slope controlled, the temporal stability of cognitive-ability tests will improve. If temporal stability improves, however, predictive validities ought also to improve.
Factors in Predicting Success in the Acquisition of Cognitive Skill
Authors: Kyllonen Patrick C.
Published: January 2009

This paper reviews two studies that have examined the relationship between performance on basic cognitive tasks, administered on microcomputers, and performance on two learning tasks. One learning task involved computer programming, the other involved learning to trace signals through logic gates, a component of electronics troubleshooting skill. From previous research, we have established a four-source framework: we assume that observed learner differences are due to differences in processing speed; processing capacity; and the breadth, extent, and accessibility of conceptual knowledge and procedural and strategic skills. In both studies, we attempted to predict the proficiency (i.e., speed and accuracy) with which individuals were able to acquire skill in the domain area (programming, troubleshooting) as a function of their scores on the four cognitive factors. Each cognitive factor was indicated by performance on two computerized tests. Skill acquisition proficiency on the learning tasks was decomposed into separate scores for (a) speed of acquisition of the initial declarative foundations of the skill (the facts), (b) speed of acquisition of the ability to apply the factual knowledge to solve domain problems (the skill itself). In both studies, working memory capacity was the best predictor of both the speed with which domain facts were learned, and of one's ability to translate those facts into rules that could be employed in problem solving.
A Macroergonomic Approach to Designing a University College
Authors: Hendrick Hal W.
Published: January 2009

The sociotechnical system components of the University of Denver's newly formed College of Systems Science were assessed using a macroergonomic approach to determine their implications for the College's organizational design. The resulting analysis led to the structuring of the College's organizational complexity including integrating mechanisms, degree of centralization, and formalization. These, in turn, have guided much of the design of specific jobs and human-machine interfaces. The macroergonomic assessment and resulting organizational design are described.
Quality of Life for Shift Workers and Their Families
Authors: O'Connor Janie
Published: January 2009

Non-traditional working hours are a “way of life” for those people who work a shift rotation. Laborers who work day, afternoon, and night shifts in a three week period often complain of digestive problems, a feeling of disorientation and problems with family and social relationships. Their families reported a lack of effective communication and limited involvement in traditional family celebrations/events. This paper describes the educational program which resulted from the cooperative efforts of the Minnesota Extension Service, industry, and shift workers' families. The program helped to provide some alternatives for families as they attempted to manage this stressful lifestyle.
Participatory Ergonomics: Current Approaches to Improving Organizational Effectiveness and Quality of Work Life
Authors: Brown Ogden
Published: January 2009

Participatory ergonomics is an idea whose time has come! There are many approaches which have been utilized by organizations to improve productivity and enhance quality of work life. Participation itself is not a new idea, but because of current organizational and environmental forces for change, new organizational philosophies are emerging which are developed, designed, and operated with participation of the employees concerned and which do result in improved organizational effectiveness and quality of work life.

Organizations in the turbulent environments of today must be able to quickly adapt to conditions of change. Many major forces for change have emerged which significantly impact managerial philosophies and behaviors. In this decade, in fact, the rules of business have changed drastically and permanently. Market conditions, foreign competition, and high growth markets are major forces in today's environment along with societal values, composition of the labor force, type of product, and the general business environment itself. An effective approach to management would suggest that it address these forces for change in order to adapt and succeed.

No single approach utilizing participatory techniques is universally effective: a contingency approach is advocated. Basic assumptions underlying a contingency model include the notion that no single approach will be effective under all circumstances, and that most approaches utilized today will be effective under a certain set of conditions. It appears that some form of participative management meets current needs primarily because it best suits the labor force, today's technologies, and current societal conditions.

The major participative management approaches discussed include quality circles (currently the most popular), job enrichment strategies, cooperative union-management quality of work life programs, gainsharing plans, and the development and operation of self-managing work teams. Also discussed is an emerging innovation in participative management, use of the parallel organization. There are other methods available, to be sure, but these appear to be the principal participative approaches of today.

Most participatory approaches and techniques are not new. What is new and very important is the commitment on the part of the organization to adopt what may become organization-wide change strategies through the use of participatory management strategies. The ultimate goal, of course, is to achieve improved organizational effectiveness, product quality, and enhanced quality of work life.
Solution Bias in Complex Systems Modeling
Authors: Kaplan Bruce , Mecherikoff Mike , Blackman Harold
Published: January 2009

Each discipline tends to use analytic tools that lead them to solutions within their own discipline, and steer them away from others. Within a discipline, we tend to pose solutions that align with our areas of interest or expertise. Clients can be guided into work which may not be the best solution to their particular set of problems or needs.
A Strategy for Managing the Organizational Impact of Computers in Small Businesses
Authors: Davis-Coury Lane , Coury Bruce G.
Published: January 2009

Human Factors can play an important role in the implementation of computer systems in small companies. The degree of effectiveness is dependent upon a thorough understanding of the unique characteristics of that group of users. This paper discusses the special problems associated with small companies and presents a strategy for effectively introducing new technology.
Technical Comparison of 8-vs-12 Hour Shift Schedules: A Case Study
Authors: Klein Marty
Published: January 2009

An analysis of the social, biological, fiscal, and operational characteristics of a 12-hour shift schedule, as compared to an 8-hour shift schedule, was conducted for two employee groups in the power industry. The 12-hour shifts appeared to have social advantages; the biological effects were questionable at best; and the fiscal and operational consequences were clearly disadvantageous.
Identifying and Weighting Factors Effecting Work in a Mechanized Office Environment
Authors: Bender Henry E. , Conte Vincent , Bannecker Richard
Published: January 2009

Decision making concerning the allocation of and distribution of funds in highly automated or computerized offices is often biased by the orientation of the decision maker, and the previous cost benefit analysis of the “system” implementation study. In such an environment, costs are often allocated to hardware or software enhancements, without regard to other factors potentially influencing worker productivity or efficiency.

The present study addressed the problem of developing a methodology that would allow for the most expansive listing of factors influencing worker productivity or efficiency. The method used allowed for the greatest amount of input from subject matter experts as well as from system users.

The data gathering method is described that facilitated the development of a questionnaire method implemented in a work environment of a major inventory and control system office. The data analysis indicates the functionality of the method, and its usability in a vast number of environments.
The Evolving Role of Task-Group Leaders, A Field Study
Authors: Randolph Robert F.
Published: January 2009

Leaders of task-oriented production groups play an important role in their group's functioning and performance. That role also evolves as groups mature and learn to work together more smoothly. The present study uses a functional analysis of the evolving role of supervisors of underground coal mining crews to evaluate the impact of supervisors' characteristics and behaviors on their crews' efficiency and safety, and makes recommendations for improving supervisory selection and training. Data were gathered from a sample of 138 supervisors at 13 underground coal mines. Detailed structured observations of the supervisors indicated that most of their time was spent attending to hardware and paperwork, while comparatively little time was spent on person to person “leadership”. The findings point out that while group needs changed over time, the supervisors' behaviors typically did not keep pace and probably restricted group performance.
NCR 7824 Scanner/Scale: An Ergonomic Solution for the Retail Checkout Environment
Authors: Hoffman Mark S.
Published: January 2009

Barcode scanning has been instrumental in increasing user productivity and has expanded the capture of product information, and inventory control. The Human Factors Group in NCR has been a major contributor to the design of scanners.

The 7824 Scanner/Scale was introduced in 1986. It was designed to provide an ergonomic solution to excessive lifting to weigh produce and meats during the transaction process. This product filled a growing market in customer service; that is to weigh produce and frozen meats within the transaction process rather than require customers to purchase prepackaged fresh foods.

The success of the 7824 exceeded expectations because of the influence of ergonomics on market demand. Throughput performances for weighed items improved from 2.1 to 3.4 seconds per item, depending upon workstation configurations. Improvements in throughput are attributed to reductions in physical and psychological workload.
Utilization of Direct Estimation Method to Determine the Effects of Task Variables on the Capacity to Lift Loads
Authors: Aghazadeh F. , Lee K.S. , Waikar A.M. , Bittner A.C.
Published: January 2009

This paper presents results of a pilot study in which the “direct estimation” method was used to determine the lifting capacity of individuals. Using the capacity of subjects to lift a load from floor to overreach height at frequency of 4 lifts per minute as a base, their capacity to lift under condition of varying task variables was determined. In this study 9 lifting heights, 5 frequencies, and 3 box sizes were used. The amount of load which the subjects were willing to lift was determined by the standard psychophysical methodology. Then the subjects lifted the same loads to various heights at different frequencies using different size boxes. A relationship was established between load lifted to the various lifting heights and the perceived difficulty of the lifting task. A similar relationship was determined for various frequencies and box sizes. An analysis of the results of this methodology reveals that the use of “direct estimation method” provides the effects of task variables on the amount of the lifted load accurately in a short period of time.
Development of An Expert Systems for Ergonomic Workplace Design and Evaluation
Authors: Jung Eui S.
Published: January 2009

Industrial workplace design and evaluation is the outcome of a multi-factored process which requires diverse disciplines and interrelated techniques to consider alternative factors and to achieve an optimal design solution. However, it is still evident that industrial workplace design fails to incorporate ergonomic principles throughout all stages of design and evaluation, One approach to solve the problem is to introduce an expert system for integrating existing analytic models and expertises into a framework which guides the designer along the necessary steps to reach a solution, with explanations on its reasoning process. This paper discusses the framework of the prototype expert system being implemented using VM/PROLOG on IBM VM/CMS mainframe. The rule-based production system was selected as a representation scheme due to its versatility and expressive power. It is consisted of two main parts, First, modularized knowledge bases incorporate multidisciplinary ergonomic factors such as biomechanics, work physiology, and psychophysics. Each module stores knowledge either in the fact base or the rule base, however, massive experimental findings and table-lookups are separately stored in the external database through its interface and retrieved without bothering the main inference mechanism. Secondly, inference mechanism was built as a control mechanism, with a front-end user interface. It has a pattern-directed architecture coupled with a normal forward/backward chaining mechanism. The prototype expert system also incorporates analytical models (usually written in FORTRAN) into the reasoning process so that it is highly flexible to the problem specificity.
The Edge System: Ergonomic Design Using Graphic Evaluation
Authors: Evans Susan M. , Palmiter Susan L. , Elkerton Jay
Published: January 2009

EDGE is a computer-based ergonomic workspace design system which integrates several models of operator performance with a common graphic interface. In addition to serving as a practical design system, it also serves as a research tool for understanding the ergonomic design process in industry. System users include trained ergonomists and engineers responsible for manual workspace design. The design system centers around a core vocabulary of task-related terms. A common input format, modeled after the traditional “work methods table” addresses the input requirements of the varied human performance models. Output from the performance models is displayed on multiple screens in varying levels of detail. Among the measures of physical stress currently integrated into the system are models of biomechanical strength, NIOSH lifting limits, metabolic energy expenditure, and elemental time prediction.
Operational Assessment of Simulator Fidelity in the Nuclear Industry
Authors: Plott Christopher , Wachtel Jerry , Laughery K. Ronald
Published: January 2009

The Nuclear Regulatory Commission (NRC) has recently developed a procedure for inspecting nuclear power plant control room simulators. These inspections will ensure that the simulator has sufficient fidelity to produce an appropriate medium for the conduct of operator licensing examinations. The difficulty in obtaining objective data for the assessment of fidelity, particularly for transient or accident events, requires that the inspection be performed primarily from a behavioral perspective rather than a strictly engineering perspective. This paper briefly describes the procedure developed.
Similarities and Dissimilarities in the Measurement of Human and Robot Performances
Authors: Genaidy A. M. , Duggal J. S. , Mital A.
Published: January 2009

This paper provides a review and evaluation of the Techniques currently used in the measurement of human and robot performances. Furthermore, a strategic model is presented which may assist job designers in the selection process between humans and robots.
An Ergonomics Program to Control Cumulative Trauma Disorders in a Manufacturing Environment
Authors: Gutekunst Kevin R. , Fogleman Maxwell T.
Published: January 2009

Cumulative trauma disorders (CTDs) at a manufacturing facility rose greatly from 1985 to 1986 and remained high through 1987. This rise resulted in time lost by injured workers and greater employee compensation for medical expenses. An action team evaluated the problem and suggested both short-term solutions and a long-term program for fewer CTDs. This work included historical research, job observation, videotape, interviews, and direct involvement of the workers. Short-term solutions included work station redesign, developing tailored holding fixtures, and designing ergonomic tools. The long-term program suggested a job rotation scheme, education about the causes and prevention of CTDs, and continued action team involvement. These efforts will continue, and the lessons learned will be applied at other company sites.
Trunk Muscle Loading in Non-Sagittally Symmetric Postures as a Result of Sudden Unexpected Loading Conditions
Authors: Lavender Steven A. , Sommerich Carolyn M. , Sudhakar L.R. , Marras William S.
Published: January 2009

The present study investigated the effect of warning time and magnitude of an external loading on the trunk muscular response to sudden loading conditions while in a non-sagittally symmetric posture. Eleven subjects were asked to catch falling weights of three magnitudes (3, 6, and 9 kg) with four levels of warning time (0, 100, 200, and 400 ms) in an asymmetric posture. For each of the eight muscles sampled with surface electrodes the integrated electromyographic (EMG) signal was interpreted in terms of its peak value, mean value, onset rate, and lead/lag time with reference to the weight drop. Results show monotonic relations between muscle force and levels of warning time, and muscle force and levels of weight. In addition, muscular forces in the left posterior trunk musculature ranged between two and five times greater than the right posterior trunk musculature in response to sudden loading conditions. This experiment demonstrates how sudden asymmetric loading, and specifically sudden loading without adequate warning time may be involved in the development of low back pain.
The Effects of Asymmetry, Load Level, Start Position and Load Velocity on Lumbar Motion
Authors: Mirka Gary A.
Published: January 2009

In order to completely understand and model the dynamic lumbar spine one must understand not only the forces acting about the spine but also the motions of the lumbar region as well. This study was an investigation in to the effects of certain lifting parameters on the motions of the lumbar spine. The effects of asymmetry, load velocity, start position and load weight on the range of motion, angular velocity and angular acceleration of the lumbar spine were investigated in three planes: coronal, sagittal and transverse. The results indicate trade offs between the coronal and sagittal planes as a result of changes in asymmetry and changes in the lifting style as a result of increasing lift velocity. The results also indicate that the location in time of the peak accelerations are varied as a result of different lifting conditions.
Physiological Responses and Subjective Discomfort of Simulated Whole-Body Vibration from a Mobile Underground Mining Machine
Authors: Bobick Thomas G. , Unger Richard L. , Gallagher Sean , Doyle-Coombs Diane M.
Published: January 2009

The U.S. Bureau of Mines has developed an in-house facility to evaluate selected effects of whole-body vibration (WBV) levels experienced by underground mobile equipment operators. Vertical vibration data were collected from a coal haulage vehicle via a uniaxial accelerometer attached to the machine frame under the operator's seat. Data were analyzed and processed so a computer-controlled platform could approximate the vibration signals. Eight men (35.5 yr ± 6.5 SD) participated in a pilot study to evaluate the effects of shock and WBV on heart rate (HR), blood pressure (BP), and subjective discomfort. Subjects were exposed to vibration for 30-min periods while seated in a typical seat (backrest angle at 90° or 130°) that was plain steel or modified with 2 in foam padding. Subjects repeated the same protocol on a separate day, without the vibration. Results indicated the vibration significantly increased the HR (p < 0.01), systolic BP, mean BP, the number of times subjects reported discomfort, and overall subjective discomfort rating (p < 0.05). When seated in the steel seat, the overall discomfort rating (p < 0.001) and the number of times discomfort was reported (p < 0.05) increased significantly. Seatback angle had no significant effect on any of the dependent measures.
Physical Demands of Lineworkers
Authors: Doolittle T. L. , Spurlin Oscar , Kaiyala Karl , Sovern Dennis
Published: January 2009

The occupational classification of electrical transmission lineworker was subjected to extensive job analyses. Physically demanding tasks, that were identified as being bona fide occupational requirements, were studied in depth to elucidate the specific forces necessary to perform them. The tasks were clustered by standard anatomical movements for lifting, pushing and hoisting. Five strength and three work simulation tests were developed to evaluate an individual's capacity for these movements. Ergonomic principles that relate the percentage of an individual's capacity to the frequency at which he or she may safely perform were employed in establishing scoring standards. Metabolic energy requirements were determined for those tasks having a high aerobic demand, and standards for performance were likewise established. Statistical analyses, comparing the test performance of 48 current lineworkers with job success criteria, revealed that the content valid test battery also possesses criterion-related validity.
Do those Scanners Really Make a Checkers Life Easier?
Authors: Schmidt John K. , Gotschall Glen E. , Schipani Salvatore P. , Kysor Kragg P.
Published: January 2009

The advent of modern optics technology has decidedly changed the face of inventory control. It is now commonplace to see optically read “bar codes” on things. One popular application has been in supermarkets. Generally, optical scanners are used to read “UPC” labels that are linked with price and inventory information databases, that respectively permit automatic pricing and inventory monitoring. This technology is also contended to eliminate fatigue caused by searching for prices and entering them into a cash register keyboard. However, along with this benefit comes a drawback, the physical overload caused by repetitively handling items, grabbing and manipulating them to properly set the bar code over the scanner, scanning the items by passing them in an extended position over a optical reader (sometimes more than once), and placing them beyond the location of the optical reader. The present paper examines three optical scanner stations and proposes various ergonomic design changes to make them more well suited for checkout personnel.
The Effect of Angled Hammers on Wrist Motion
Authors: Schoenmarklin Richard W.
Published: January 2009

This research investigated the range of wrist motion characteristics associated with the ergonomic principle of “bending the tool and not the wrist” as applied to the hammer. It is thought that bending the tool reduces wrist motion, which has been shown in the literature to be a risk factor in hand/wrist disorders, such as carpal tunnel syndrome, tenosynovitis, etc. Bent hammer handles resulted in a tradeoff in beginning and ending positions of the wrist throughout a hammering stroke. Bending the hammer handle to 20 or 40 deg. resulted in significantly less ulnar deviation than a straight hammer, but also increased radial deviation. Overall, the angular deviation from neutral position in the radial/ulnar plane was significantly less for the 20 and 40 deg. hammers than for the straight hammer. This research suggests that angled hammer handles in the range of 20 to 40 degrees could possibly decrease the incidence of hand/wrist disorders caused by the use of hammers.
The Effects of Gloves on Grip Strength and Muscle Activity
Authors: Sudhakar L.R. , Schoenmarklin R.W. , Lavender S.A. , Marras W.S.
Published: January 2009

The focus of this research was to investigate how grip strength and forearm muscle force were affected by two types of gloves, rubber and leather. Grip strength was significantly less in the two gloved conditions than in a barehanded condition. However, EMG analysis of muscle activity revealed no significant difference in muscle activity across the gloved and barehanded conditions, indicating that subjects generated maximal exertions in all conditions. Therefore, a certain amount of muscle force is lost in the hand-glove interface while producing maximal grip forces in the gloved conditions. Internal muscle force measurement could thus be used to aid in glove selection for submaximal tasks in industry.
Trunk Muscle Response to Trunk Asymmetry, Velocity, and Load Level
Authors: Marras W. S. , Mirka G. A.
Published: January 2009

A significant amount of epidemiologic evidence suggests that asymmetric motions of the trunk during lifting are related to the risk of low back disorders. However, a void exists in the biomechanical literature which describes how the internal forces of the trunk respond to these motions. An experiment was performed to investigate this relationship. Eighteen subjects were asked to produce lifting motions of the back under highly controlled conditions. Trunk asymmetry, angular concentric and eccentric velocity, torque production, and trunk position were controlled while the activity of ten trunk muscles was observed. This article presents preliminary data from this experiment. Saddle-shaped response surfaces described the reactions or “costs” to the muscles to the various controlled variables. These trends are described and the effects of these trends on spine loading and biomechanical modelling are discussed.
The Relative Pleasantness and Distinctiveness of a Variety of Auditory Patterns
Authors: Roberts Linda A. , Angiolillo-Bent Joel
Published: January 2009

There are numerous instances in which auditory patterns could be employed to give a variety of signals or messages. The aim of this research was to investigate those sound qualities which contribute to an auditory signal's pleasantness and distinctiveness. A variety of auditory schemes were assesed, based on a number of different musical and acoustic dimensions. It was observed that patterns that varied along the rhythmic domain were most easily distinguished while frequency modulated intervals were judged to be most pleasant. The scheme-that optimized both-distinctiveness and pleasantness entailed four-note melodic sequences.
Considerations of Intention and Movement: Action Plans and Motor Programs in Speech and Keyboard Entry
Authors: Mullins Patricia A.
Published: January 2009

The cognitive organization and control of rapid movement sequences was investigated in speech and keyboard entry. Five reaction time experiments were carried out with various manipulations of stimulus meaning. A linear increase in reaction time with an increase in the number of items to be produced was evident for spoken lists of random digits, single words in random order, and repeated syllables but not for single words arranged into meaningful context. A speech interference condition produced a linear increase in reaction time in a key pressing task when it was necessary for the action to be planned ahead of time. These results indicate that meaningfulness of stimuli facilitates movement organization, an effect which can have significant impact on input technology.
Ambient Heat and Nerve Agent Antidotes: Effects on Soldier Performance with the Usariem Performance Inventory
Authors: Johnson Richard F. , Kobrick John L.
Published: January 2009

The tactical significance of chemical weapons in future warfare demands that nerve agent antidotes be available for troops exposed to chemical attack. Since future combat operations will likely occur in desert and tropical areas, chemical attacks in such areas could lead to situations involving the use of nerve agent antidotes by troops during exposure to hot weather conditions. This study assessed, both independently and in combination, the effects of heat exposure (95°F, 60%RH) and US Army standard dosages of nerve agent antidotes (2 mg atropine and 600 mg 2-PAM chloride) on the performance of a variety of tasks selected from the USARIEM Performance Inventory (UPI). The UPI tasks selected for inclusion assessed sensory functioning, perceptual-cognitive functioning, sensorimotor skill, subjective reactions, and M16 rifle marksmanship. Fifteen soldier volunteers were first trained to asymptotic performance on the UPI task battery. Then, over a period of four test days, they completed a counterbalanced schedule of the drug/no drug and heat/no heat conditions while outfitted in the Battle Dress Uniform. On each test day, the tests from the UPI were administered once during each of the three 2-hour test cycles. Compared to the placebo condition, a single dose of nerve agent antidote significantly impaired soldier performance such that visual reaction time was 5 to 11% slower, gross body mobility was 12% poorer, rifle marksmanship (pop-up targets) was 3% less accurate, and verbal reasoning was 6% slower. Compared to the 70°F condition, the 95°F ambient condition significantly impaired soldier performance such that arm-hand steadiness was 10% poorer, manual dexterity was 2% poorer, and rifle marksmanship (tightness of shot group) was 13% less accurate. Nerve agent antidote and ambient heat did not interact to further impair soldier performance.
Car Seat System of the Future as Seen in “ARC-X”
Authors: Hanai Toshimichi , Nagashima Hideyuki
Published: January 2009

Car seats of the future will have to give even greater consideration to the human aspects of comfort and style. Moreover, driver and passenger seats need to be designed separately, to optimize each seat according to its function and location the car interior. The seat system of the “ARC-X” experimental car is based on the results of body pressure distribution measurement, subjective evaluation, and other human engineering techniques. These were used to analyze driver and passenger postures from the standpoints of performance and comfort. This paper introduces features of the driver's seat and front and rear passenger seats adopted in the “ARC-X”, and reports some of the analytical results on which their design was based.
Modeling Driver/Vehicle Performance in Emergency Maneuvers
Authors: Allen R. Wade , Szostak Henry T. , Rosenthal Theodore J.
Published: January 2009

The combined performance of the driver and vehicle determine whether accidents result from traffic conflicts, road hazards, etc. This paper describes the driver behavior and hazard scenario aspects of a computer simulation which models both vehicle dynamics and driver steering and braking behavior. The technical aspects of the simulation have previously been published. The issue of how much the driver and vehicle contribute to accident involvement is addressed, and antilock brake evaluation is used as an example.
An Examination of Body Support and Fatigue in Automobile Seats
Authors: Date Kuniyoshi
Published: January 2009

There are various factors that influence the sitting comfort of automobile seats. Important elements that of en determine how a seat is assessed in terms of sitting comfort are the fatigue phenomena that occur on long drives. This work examined the possibility of reducing fatigue by providing an optimum fit between the seat and the occupant's body and optimum sitting posture. This report presents the results of evaluations and analyses made of fatigue and the feeling of fit for many different types of seats, including a bucket seat.
A Comparison of Equations and Methods for Determining Percentage Body Fat
Authors: Fernandez Jeffrey E. , Pitetti Kenneth H. , Stubbs Nancy B. , Marley Robert J. , Cihangirli Mihriban
Published: January 2009

An experiment was conducted to assess the differences between various equations and devices for estimating body fat percentage. Valid estimation of body fat is an important variable in determining the individual differences in energy expenditure or physical work capacities of workers performing various tasks. Twenty male volunteers participated in this study. Results indicate that no significant differences exist between device type. However, there were significant differences between derived estimations of body fat content with several widely used equations. These results were also related to estimation of body fat content derived from the bioelectrical impedance procedure. Results from this study indicate the need for comparison between subject population and population of prediction models before determining body fat and possible use of an average of several equations.
Relative Contribution of Behavior to Slip and Fall Accidents in Mining Maintenance
Authors: Albin Thomas J.
Published: January 2009

Bureau of Mines research has indicated that slip and fall accidents are a major cause of injuries during the maintenance of surface mining equipment. All such injuries during 1985, 1986, and the first half of 1987 were studied for information as to accident causes, particularly whether the nature of the causes were worker behavior or machine design. Accidents judged to be solely caused by behavior of the injured individual constituted only 11 pet of a total of 1384 accidents. An interaction of machine design and behavior was found to be involved in 31 pct of the accidents. The information presented in this study as to antecedent events to slip and fall accidents may be useful in designing intervention strategies to decrease slip and fall injuries.
Help for the Handicapped, or Hindrance?
Authors: Schmidt John K. , Schipani Salvatore P. , Kysor Kragg P.
Published: January 2009

During the Seventies, legislation was enacted to open areas to the physically handicapped. Subsequently, newer structures began to accommodate the physically disabled, whereas older structures were systematically modified to increase accessibility. The intent of the present effort was to examine a train station overpass intended to provide access to the handicapped and determine if the requirements it imposes on its users were feasible. The analysis indicated that the current design places excessive demands on users, and should be modified. The paper suggests some possible modifications for the present structure.
“Recommended” versus “Preferred” in Design and Use of Computer Workstations
Authors: Povlotsky Boris , Dubrovsky Vitaly
Published: January 2009

Due to the recent development of adjustable office furniture and elements of computer hardware, a new “preferred settings” approach to VDT workstation (VDTW) design has emerged in opposition to the traditional recommended standards. This approach studies the “recommended - preferred” controversy on the population level in terms of means, ranges, and percentiles and sets new dimensions and ranges of adjustment for the design of the VDTW components. While the VDTW's components are designed in a view of population, they are used by individuals. This paper raises the issue of studying the “recommended - preferred” controversy on the individual level in relation to the task of customizing VDTW's for individual users. Preferred individual adjustments of the experimental VDTW made by 23 subjects were compared to the respective, recommended individual adjustments. Although all recommended-preferred differences were statistically significant, almost all preferred values were either very close to the corresponding recommended values or deviated from the recommended optima without exceeding the recommended ranges. The paper discusses implications of this result for the customizing of the VDTW's for individual users.
Standing Work: Carpet vs. Concrete
Authors: Rys Malgorzata , Konz Stephan
Published: January 2009

A significant part of the workforce works with the feet and legs in a relatively static standing position.

In an experiment, 20 college students (mean age = 23) stood wearing 2 pairs of socks but no shoes at a table for 240 minutes (120 minutes on carpet on one day and 120 minutes on concrete on another day). Ten subjects stood in the morning and 10 in the afternoon. Foot volume and instep vertical and horizontal circumference and calf circumference did not differ significantly between morning and afternoon or between carpet and concrete. Heart rate did not differ between morning and afternoon but the 95.2 for carpet was significantly lower than the 100.1 for concrete. Perceived comfort ratings were higher for carpet than concrete. Body areas in which comfort decreased the most while on concrete were: lower leg, upper leg, ankle, whole foot, the neck and the shoulder. When the individual factors were combined into a single factor using factor analysis, the 77.7 score (0–100 scale) for carpet was significantly better than the 71.9 for concrete.
Designing for Usability: The Next Iteration is to Reduce Organizational Barriers
Authors: Gould John D.
Published: January 2009

This is a draft of the 1988 Human Factors Society Presidential address. A system design philosophy for developing useful, usable systems and products, which we have been advocating since 1980, is first reviewed. The toughest nuts in carrying out the ideas are organizational barriers and resistances. The key ideas in this paper are proposed technical approaches to facilitate organizational changes. The approaches are described in general terms, and their feasibility await successful research outcomes.
Simulation of a Power Wheelchair
Authors: Lefkowicz A. Todd
Published: January 2009

A computer-based wheelchair simulation will be demonstrated. Such a wheelchair simulator could be used in rehabilitation both to prescribe controls for patients and to develop new types of wheelchairs. The selection of a wheelchair controller and control dynamics for a specific patient currently involves the actual use of a variety of power wheelchairs. A valid simulator could reduce costs by eliminating the need to test and evaluate a set of power wheelchairs for each patient, increase safety of the patient by eliminating the risk associated with learning to operate a new power wheelchair, and ease collection of performance data by providing automated data collection. Further, the simulation could be used to test control dynamics as related to the user's perspective view when developing new power wheelchair products. The simulation runs on a personal computer with low resolution color display. The realism of the display is augmented by the use of a Fresnel lens to increase the three-dimensional effect. The display is updated frequently to ensure accurate control feedback. The performance measures used to test the simulation include both time and accuracy to move through a computer simulated course and an identical physical course. The initial results from user testing are being used as the basis for an iterative redesign process before formal testing is initiated.
Crew Requirements Definition System Demonstration
Authors: Christ Richard E. , Conroy Joseph A. , Robertson Robert E.
Published: January 2009

The crew requirements definition system (CRDS) is a computer-based methodology designed to minimize the time required to accomplishment any set of tasks while using the fewest resources. It enables analysts and researchers to study in a timely and cost effective manner the effects of varying crew size, task start times (and hence task sequencing), and task allocation to crewmembers or equipment items during the performance of designated missions without the need to observe crews actually performing their duties.

The CRDS is programmed in C-language and is designed to be used on an “XT” or faster class of personal computer. The basis of the system is several automated PERT, GANTT, and critical path method calculations. In addition, the system produces other automated calculations and summaries to aid the user. The user should have some knowledge of these operations research techniques to use the system effectively. Also needed is an understanding of the tasks to be performed, the personnel and equipment items available to perform the tasks, each task's duration, and any requirements for task sequencing.

The U.S. Army Research Institute for the Behavioral and Social Sciences (ARI) developed the CRDS for the Force Design Directorate at the U.S. Army Combined Arms Combat Development Activity. However, the system is useful in any military or civilian situations in which there is a need to design and evaluate alternative small unit organizational structures. The system can be used whenever the user has some knowledge, or is willing to venture some guesstimates, of the tasks that need to be performed and the capabilities of various assets to perform those tasks.