bluuebunny/crossref_metadata_2025 huggingface dataset:
A Task Analytic Investigation of Safety in Industrial Radiography
Authors: Wheeler William A. , Toquam Jody
Published: January 2012

Industrial radiography is a commonly used method of inspecting materials for flaws. These inspections use small but significant quantities of radioactive material to penetrate the inspected object and expose corresponding radiographic film. The film is then examined to determine if there are any indications of flaws in the inspected material. Failure to perform industrial radiography properly can result in serious injury due to radiation exposure. An examination of accident reports and annual radiation dose rates for industrial radiographers suggests safety in this field is an important concern. This paper describes how an observation-based, two-part, task analysis was developed and conducted for this potentially hazardous process.
Real-Ear Attenuation under Laboratory and Industrial Test Conditions as Provided by Selected Hearing Protectors
Authors: Casall John G. , Park Min-Yong
Published: January 2012

To determine if controlled laboratory measurement procedures could yield realistic estimates of actual hearing protector performance achieved in the workplace, laboratory and field studies were performed using a like set of test protocols and hearing protection devices (HPDs). The laboratory experiment, using 40 naive subjects, investigated the effects of HPD wearing time, activity movement, and 2 fitting conditions (naive subject-fit vs. trained subject-fit), on spectral attenuation afforded by a slow-recovery foam earplug, premolded plug, foam cushion earmuff, and the muff worn over the foam plug. The field study, using 40 noise-exposed industrial workers, determined the protection obtained over 6 weeks of HPD use in 5 industrial workplaces. Statistical contrasts of mean data across frequency showed that the laboratory post-activity task (i.e., worst case) attenuation results overestimated the field attenuation by 8.3 dB (under the subject-fit) and 5.7 dB (under the trained-fit) for the user-molded foam plug, and by 10 dB and 6 dB, respectively, for the premolded plug. The laboratory results provided a much better prediction of field protection for the earmuff than for the plugs. Because of the discrepancies in prediction accuracy for different types of HPDs, schemes which have been proposed to “derate” the manufacturers' attenuation data by a constant factor across protectors are not justifiable.
Factors Influencing Drivers' Left Turn Decisions
Authors: Hancock PA , Caird J.K. , Shekhar S. , Vercruyssen M.
Published: January 2012

An experiment is reported which examined drivers' responses in turning left across a line of traffic as presented in a closed-loop, interactive, fixed-base driving simulator. Drivers were located near an intersection and instructed to turn left across a stream of on-coming traffic when they felt that it was safe for them to do so. The on-coming stream of traffic was varied in terms of the physical parameters of approach velocity, inter-vehicle time interval, and vehicle type. Specifically, seven velocities (10–70 mph) were crossed with seven gap sizes (3–9 sec) to yield forty-nine within-subject conditions for each of four, between-subject, vehicle types; motorcycle, compact car, large car, and delivery truck. There were ten subjects per vehicle type, giving forty total participants in the experiment. Results indicated differential acceptance of gap and velocity combinations depending upon the type of approaching vehicle. Collisions tended to occur along the boundaries where driver's decisions to reject or accept turns were ambivalent. They also occurred with greater frequency at higher velocity approach rates. Turn decisions were not dependent upon a single physical parameter such as vehicle velocity or inter-vehicle distance, although gap-size generated an arguable influence. Rather, left turn decisions appeared to result from the complex interplay of rate-of-change perceptual variables such as “time-to-contact” and the perceived characteristics of the vehicles themselves. Implications of the results are discussed with respect to the perception of vehicles and turn safety at roadway intersections.
A Testbed for Teaching Problem Solving Skills in an Interactive Learning Environment
Authors: Guerlain Stephanie A. E. , Smith Philip J. , Miller Thomas E. , Gross Susan M. , Smith Jack W. , Rudmann Sally
Published: January 2012

An interactive learning environment was developed with the goal of empirically testing the effectiveness of various teaching strategies in improving problem solving performance. The domain chosen was transfusion medicine since it involves solving complex, multiple solution problems which are typically found to be difficult (Elstein, Shulman, and Sprafka, 1978) and because normal performance of this task calls for marking data sheets with intermediate conclusions, thereby improving the chances of the computer correctly inferring the student's reasoning. The testbed, called TMT (for Transfusion Medicine Tutor), monitors for errors, builds a model of what a student knows and can select teaching strategies based on human tutoring models that were developed from earlier studies. The testbed will be used to collect data of a student's performance in conditions where the degree of teaching and type of feedback are manipulated. A number of broadly applicable issues can be explored in this framework such as the difference between expert and student problem solving strategies, the effectiveness of different teaching strategies, and the importance of modeling student knowledge and providing visual feedback when developing an interactive learning environment. Preliminary results of our experiments, a demonstration of the testbed, and a discussion of how it was implemented will be presented in the demonstration session.
An Electronic Assistant for Scientific Investigation Working Prototype
Authors: Schur Anne , Feller Dave , DeVaney Mike , Thomas Jim , Yim Morgan
Published: January 2012

Although many automated tools support the productivity of professionals (engineers, managers, architects, secretaries, etc.), none specifically address the needs of the scientific researcher. The scientist's needs are complex and the primary activities are cognitive rather than physical. The individual scientist collects and manipulates large data sets, integrates, synthesizes, generates, and records information. The means to access and manipulate information are a critical determinant of the performance of the system as a whole. One hindrance in this process is the scientist's computer environment, which has changed little in the last two decades. Extensive time and effort is demanded from the scientist to learn to use the computer system. A common paradigm that meets the critical requirement of facilitating information access and retrieval by the chemist is demonstrated. This paradigm was embodied in EASI, a working prototype that increased the productivity of the individual scientific researcher.
Future Systems Development: Limits on Vision
Authors: Benel Russell A.
Published: January 2012

What we know about the rationale for the requirements for the new design is limited by the imperfect understanding of the current system and our inability to divorce ourselves from that past. This provides the basis for a conundrum. How can we become sufficiently knowledgeable and avoid the biases inherent in the process of acquiring that knowledge simultaneously? Consider carefully the lessons of history and evaluate whether the legacy of the previous system and its predecessors accelerates or retards progress toward the future. To capitalize on our experience we need to recognize facts and mythology in our understanding of the way things are and need to be. The most important question to ask is “Why?”. Without a true understanding of why, we can't develop effective, user-centered alternatives to the current system and our efforts will reduce to mere technology replacement.
Selecting Space Station Freedom Hardware
Authors: Mitchell Nancy B.
Published: January 2012

Four types of restraint attachment hardware were evaluated using the method of paired comparisons. From these four, one restraint attachment device was chosen and the result accepted by the organizations involved. Paired comparisons provided a way of handling subjective data that produced an outcome which was objectively verifiable while, at the same time, reducing personal bias. The method of paired comparisons, as used in this trade study, is portable, accommodates groups of participants, and allows each participant's input to have equal weight. These advantages argue for using paired comparisons as a basic trade study tool in the selecting hardware, hardware configurations, and software display designs especially for developing systems.
Robust Testing and Evaluation (T&E) of Systems
Authors: Bittner Alvah C.
Published: January 2012

Using “robust” testing and evaluation (T&E) components will ensure system T&E success despite unanticipated resource and schedule shocks. Selected tools for building robust T&E plans, methods, and analysis components are described. These robust tools provide a beginning framework that the practitioner can build upon to achieve successful T&Es.
The User Oriented Evaluation Process: A Process for Preserving User Needs during Iterative System Test and Evaluation
Authors: Hunt Steven , Schur Anne
Published: January 2012

A system development process, called the User Oriented Evaluation (UOE) process, and an evaluation tool were created to place greater emphasis on user needs during computer system development. The UOE process is an iterative method for design that emphasizes the role of the user as the initiator of system requirements; evolutionary design requirement definition by enabling users and developers to experiment through the use of prototypes at all phases of system design; and appropriate utilization of developer and user areas of expertise. The evaluation tool is an integral part of the UOE process and provides the ability to solicit on-line meaningful feedback from users in real-time, and a means to capture a user's on-going experience with the computer system. The paper contains a description of the UOE process and the evaluation tool, the capabilities of each and the history of their development.
Spatial Orientation and Dynamics in Virtual Reality Systems: Lessons from Flight Simulation
Authors: McCauley Michael E. , Sharkey Thomas J.
Published: January 2012

Artificial representations of virtual worlds are becoming more common due to advances in the technology of image generation and display systems. Application areas include flight simulation, mission rehearsal, teleoperator systems, and virtual reality systems. System developers should be forewarned that some proportion of users will experience perceptual anomalies and symptoms of motion sickness as a result of travel through virtual space.
Contextual Change and Skill Acquisition in Visual Search: Does the Rate of Change Affect Performance?
Authors: Lee Mark D. , Rogers Wendy A. , Fisk Arthur D.
Published: January 2012

The present investigation examined the effects of training context on the development of a skill in a semantic category visual search task. Thirty-two subjects were trained in a visual search task which allowed the separate examination of feature learning and attention strengthening. Subjects were trained in a Consistently Mapped (CM) condition which allowed both feature learning and attention strengthening, “Attenuated Strength” search conditions which allowed only feature learning, and a Variably Mapped (VM) condition which allowed neither feature learning or attention strengthening. The present experiment also examined the temporal characteristics of feature learning by manipulating the training context which was defined as the number of trials in a row that a particular search condition appeared. There were four different training contexts used (1, 5, 10, and 50) and eight subjects were assigned to each. Each subject performed 11,000 training trials. Analysis of the reaction time (RT) data indicated that within each training context, RT was fastest for the CM condition, intermediate for the Attenuated Strength conditions, and slowest for the VM condition. The results also suggest that 10 trials were sufficient for feature learning to occur. Furthermore, while there was evidence of attention strengthening in the CM condition there was no evidence of attention strengthening in the Attenuated Strength conditions. For inconsistent tasks that allow feature learning, the rate at which the context changes is a critical variable in determining final task performance.
Team Member Shared Mental Models: A Theory and Some Methodological Issues
Authors: Converse Sharolyn A. , Cannon-Bowers Janis A. , Salas Eduardo
Published: January 2012

This paper discusses the hypotheses that shared mental models enhance teamwork skills, and that superior teamwork skills increase the quality of team performance. Methodological problems encountered in the development and evaluation of shared mental models are discussed. These issues include selection of mental models that teammates should share, methods of measuring mental models, training mental models, and validation of the relationships between shared mental models, teamwork skills, and successful team performance.
Perceived Spatial Layout of a Simulated Scene as a Function of Experience
Authors: Caird J.K. , Hancock P.A.
Published: January 2012

A critical question in simulation is the degree of correspondence or alignment between what is seen in a generated graphics world and it's intended actual physical structure. An allied concern, is the role of perceptual experience as a potential influence on this perceived spatial layout. The present experiment examined the potential for these perceived distortions. Eight observers estimated the location of nine object locations embedded in a graphical scene of a traffic intersection. Participants were asked to judge the relative and absolute distances between objects in the display. Half the subjects viewed the intersection after driving for thirty minutes through the simulated traffic world while the remaining participants did not receive any prior experience. A multidimensional scaling analysis revealed differences between simulator and no simulator experience groups for absolute and relative 3-D solutions. Scaled representations of actual and perceived spaces are discussed in the framework of a model of perceived spatial layout and with respect to human factors issues in the use of both simulated and virtual worlds.
Utility of Secondary Task as a Workload Assessment Technique
Authors: Tsang Pamela S. , Velazquez Velma L.
Published: January 2012

Recently Navon (1984) suggests that much of the dual task data that lend support to resource theories are methodologically flawed and that there are non-resource related mechanisms such as outcome conflict that could explain dual task data equally well. If Navon's concerns can be validated, the current view of workload as a resource-related concept would have to be revamped. The present research examined performance tradeoff - demonstration of resource allocation - with the optimum-maximum method. The optimum-maximum method was a variation of the secondary task technique proposed by Navon to encourage maximum joint task performance without conveying to the subjects that task performances must tradeoff. A continuous tracking task and a Sternberg memory task were used; three priority levels were used to induce resource allocation. An absence of performance tradeoff with the optimum-maximum method would support Navon's claim that performance tradeoffs may not be true indications of resource competition or task demand and therefore not reliable reflection of mental workload. Performance tradeoff was observed when the tracking task was optimized. When the Sternberg task performance was optimized, Sternberg performance was sensitive to the priority manipulations but the concurrent tracking performance was not. Peripheral vision was proposed to have protected the tracking performance when subjects were visually focusing on the Sternberg stimuli. However, the peripheral vision hypothesis could not account for the graded performance changes across priority levels. The present data suggest that the resource view is still a useful concept and the secondary task technique still could provide informative disclosure about task demand and mental workload.
Computer-Generated Infrared Imagery for Combat-Vehicle Identification Training
Authors: Sheffer Albert D. , Cathcart J. Michael , Faust Nickolas L. , Montgomery James I. , Doll Theodore J.
Published: January 2012

Development of a computer-based system for generating simulated infrared (IR) imagery is described. The system provides realistic representations of IR targets and backgrounds for training soldiers in combat vehicle identification (CVI). Simulations of several fielded IR sensors enables system users to generate training imagery sets, both snapshots and animated sequences, showing realistic sensor effects. The system is workstation-based and has a user interface that permits a non-expert to generate desired imagery sets from menus of available models and scenarios.
Musical Notation for the Keyboard: An Examination of Stimulus–Response Compatibility
Authors: Biel Gary , Salmon Paul , Carswell C. Melody , Kee Brenda
Published: January 2012

The principles of stimulus-response compatibility were used to provide a performance evaluation of an experimental notation for the keyboard in which pitch varies horizontally in visual space. Subjects performed a choice reaction time task using either the horizontal notation or a more traditional vertical notation. Half the subjects in each notation group were provided white noise and half pitch-varying feedback with responses. Responses were reliably faster with the horizontal display. Further, the superiority of the horizontal display was not dependent on the nature of the feedback. In a second experiment, performance of musicians and nonmusicians was compared using the horizontal and vertical notations. Performance by musicians was equivalent with horizontal and vertical displays and uniformly better than nonmusicians. The findings fail to support the argument that horizontal visual representations will be less useful in musical tasks because they will be incompatible with the mental representation of pitch as varying vertically from ‘low’ to ‘high’.
Visual Integration of Tactile Information in Telerobotics
Authors: Browse Roger A. , McDonald Marcia L.
Published: January 2012

We have carried out three experiments which explore the effectiveness of various visual depictions of tactile data for the task in which subjects view a robot gripping an object and attempt to predict if the robot will be able to pick the object up. The display types tested range from simple total closing force values through to graphic three-dimensional contour plots, overlaid with force-torque vectors, with the subject having dynamic viewpoint control over the display.

Our results suggest that an operator's utilization of such tactile displays depends on the effectiveness of the model of the gripping configuration which can be obtained through visual images of the scene. In the case of simple planar contact between gripper and object, a total force value produced maximum performance enhancement. In more complicated, or awkward non-planar gripping, the total force value was of no use, but spatially distributed force representations could still yield enhanced performance.

Further experimentation was carried out with complex displays which subjects reported as depicting the contact forces better. It was found that these displays actually reduced performance, drawing into question the telepresence assumption that more realistic information will lead to better telerobotic operator performance.
Actions Speak Louder than Words: How Pilots use Nonverbal Information for Crew Communications
Authors: Segal Leon D.
Published: January 2012

How does the design of an aircraft cockpit affect crew communication? The research described hereunder aimed at identifying aspects of design that play a critical role in task coordination, yet have heretofore been ignored. It is proposed that crewmembers coordinate the performance of tasks using visual, nonverbal, information that emerges from the interactions between individual pilots and the aircraft's systems. 24 airline pilots participated in a high-fidelity simulator experiment which compared the impact of three different types of interface on crew communication and coordination. Measurement included detailed video recording, and quantitative and expert performance evaluations. The data suggest that pilots visually monitor each other's performance of tasks, that visual monitoring is affected by the design of the interface, and that pilots rely on such nonverbal information for communication and coordination. The discussion looks at implications of these data to the design of workstations and cockpits.
Cumulative Effects of +Gz on Cognitive Performance
Authors: Morrison Jeffrey G. , Forster Estrella , Hitchcock Edward M. , Barba Charles A. , Santarelli Thomas P. , Scerbo Mark W.
Published: January 2012

A study is described which examines the interaction of two of the most salient stressors found in the tactical aviation cockpit: 1) highly demanding decision-making tasks, and 2) intermittent periods of high G. Addressing this issue is critical because: 1) it is probable that physiological stressors such as G may have serious ramifications on pilots' abilities to perform complex cognitive tasks; 2) there may be different impacts of G on different types of cognitive tasks, and the impact of these deficits may be correlated with the cumulative amount of time a pilot has spent under G; 3) it is not clear that donning protective gear will have an effect on cognitive task performance; and 4) there are no data to suggest how long cognitive decrements due to exposure to physiological stressors will last. A general approach is described for evaluating the cumulative effects of physiological stressors (e.g., G) on cognitive task performance in a within-subjects experimental design. A PC-based task suite was used incorporating three concurrently performed tasks: a compensatory tracking task, a resource management task, and a system monitoring task. Results indicated that performance across the experimental conditions was highly variable. Preliminary results demonstrated that: 1) even low-level increases in G can be disruptive to subject performance, 2) there are cumulative decrements in task performance during G, and 3) if stable performance on tasks is required, training for complex task performance must take place in the presence of salient physiological stressors.
An In-Depth Analysis of Automatic Teller Machine Usage by Older Adults
Authors: Rogers Wendy A. , Gilbert D. Kristen
Published: January 2012

The present study investigated the usage of Automatic Teller Machines (ATMs) by older adults. We conducted 100 telephone interviews of older adults wherein we queried subjects about their frequency of ATM usage. From this pool of individuals we chose eight frequent users and eight intermediate users to participate in an in-depth structured interview. The phone and structured interviews provided detailed information about usage patterns and general ATM knowledge of older adults. The interviewing technique provided insight into the concerns of older adults and the problems they encounter when using ATM technology. The results of this study provide information relevant to design and training for ATMs. Although the data are derived from a sample of older adults, any improvements of design, safety, or training will be beneficial to the population of users as a whole.
Assessing the Older Driver: An Interdisciplinary Approach
Authors: Olsen Erik C. B. , Eberhardt John W. , Andre Anthony D. , Ball Karlene , Hunt Linda , Harwood Kim , Corn Anne
Published: January 2012

Numerous groups of professionals have been studying driving and aging for many years, including human factors researchers, occupational therapists, optometrists, and special educators. Unfortunately, however, this diverse set of professionals has not joined efforts in developing comprehensive assessment techniques for older drivers. This panel represents an important step toward supporting an interdisciplinary approach to elderly driver assessment.
Stereoscopic Telepointing in Videocommunications
Authors: Runde Detlef , Böcker Martin
Published: January 2012

Stereoscopic telepointing to be employed inter alia in cooperative telework applications yields many benefits but also poses a number of problems addressed in a study with 96 subjects under four different conditions. For two conditions, 3D-input devices were designed implementing different input metaphors. The ‘Light Beam Metaphor’ is analogous to pointing to objects with a slide show pointer or laser pointer. The ‘Reference Space Metaphor’ provides the users with the possibility of pointing to details of an object in such a way as if a re-sized model of the object was present in front of them and within reach of their hands. The other two conditions were stereoscopic and monoscopic control conditions without pointers. The subjects' task was to identify differences between a remote and a local object within a limited time. The results show that the Light Beam Metaphor pointer was easier to handle and conformed to a larger degree to the users' expectations, whereas the Reference Space Metaphor pointer received better subjective ratings on efficiency and Telepresence. The analysis of the results of all four conditions established the benefits of 3D over 2D representations for object-oriented communicative situations in terms of appeal and the impression of depth.
Design of Skill-Based Adaptive Interface: The Effect of a Gentle Push
Authors: Gong Qing , Salvendy Gavriel
Published: January 2012

To accommodate individual skill differences in using a computer interface, a skill adaptive interface was designed and tested. Current human-computer interaction modes can be classified into two types, recall and recognition based interfaces. They have different memory requirements and generally allow different operating speeds and learning time. However, a static combination of the two interface modes has drawbacks. The dynamic skill adaptive interface introduced in this study tries to eliminate these problems without sacrificing the advantages from either interface modes by gently ‘pushing’ users to switch to the appropriate interface mode. Experiment showed that the adaptive interface can yield significant better performances than the static hybrid interface for certain groups of users.
Handheld Computer Terminals: Starting off Right the First Time
Authors: Wilson Karen S. , Callaghan Thomas R.
Published: January 2012

Advances in miniaturization and wireless communications are providing the computer industry with the impetus to design handheld, portable computer terminals. Until enough research and experience evolves from handheld terminals to build a literature on design factors and to develop design guidelines and standards that would provide starting points for product design, the human factors community must rely on its user-centered design approach of designing, prototyping, and testing to ensure a safe and usable form factor for such terminals. The methodology that was used in establishing the design criteria for such a terminal included literature research, focus groups with potential users, contextual field research, expert testimony, and primary laboratory research, including a grasp analysis and screen viewability, data entry, signature capture, and holsterability testing. The user-centered design process described here provided the information required to establish the basic design criteria that would assure user safety and task efficiency. It also revealed informational needs for the human factors community involved in the development of handheld computer terminals.
Design of a Menu for Small Displays Presenting a Single Item at a Time
Authors: Han Sung H. , Kwahk Jiyoung
Published: January 2012

Electronic consumer products such as desktop laser printers, facsimiles, copiers, etc., which have a small visual display panel are ubiquitous. They are characterized by presenting only a single menu item at a time which is usually organized in a hierarchical tree structure. Since users see only a single line information on the display and use them infrequently, the optimal menu design may be different from that of an ordinary computer display. An experiment was conducted to examine variables for designing the optimal menu on a single line display. Prototypes were developed to simulate the user interfaces of several menu structures. The results showed that the search time on the small display was approximately three times longer than that on the ordinary computer display. User experience affected significantly the search performance and a menu structure with depth 2 was found to be the optimal for infrequent users. Based on the results of the experiment, human factors guidelines for designing a menu on a single line display were suggested.
User Interfaces for Different Cultures a Case Study
Authors: Hartevelt M. A. , van Vianen E. P. G.
Published: January 2012

The paper presents a case study carried out to investigate cultural differences between Japanese and European users in their use of television user interfaces. The paper describes the methods used and presents the most interesting results of this case study.
I'M Graduating, Now What? A Comparison of Work in Academics, Consulting, Government, Industrial Research, and Industrial Development
Authors: Shapiro Ronald G. , Beith Barry , Goldberg Joseph H. , Hale Joe , Kelley John F. Jeff
Published: January 2012

The purpose of this panel is to familiarize students and faculty members with what Human Factors Professionals do in a variety of settings including academics (Joe Goldberg), consulting (Barry Beith), government (Joe Hale), industrial research (Jeff Kelley), and industrial development (Ron Shapiro). This panel compares some of the advantages and disadvantages of various career options to help student determine where they best fit, and to help them prepare for interviews.
Educating People with Disabilities
Authors: Mital A. , Deivanayagam S. , Malzahn D. , Wiker S. , Vanderheiden G. C. , Freivalds A.
Published: January 2012

Accommodating individuals with disabilities in the workplace is a rapidly growing concern. Furthermore, those who are functionally impaired are in a dire need of assistance. In a classroom, the main function of a student is to learn. Learning is facilitated by an instructor's lectures, writings on the board, use of audiovisuals, etc. Generally, it is presumed that students do not have any common functional impairments (visual, auditory, etc.) and, therefore, no special effort is made to accommodate those who may have such impairments. Obviously, the learning of a legally-blind student or one who has impaired hearing, for example, will be compromised if no assistance is provided. Then there are issues such as providing reading materials for the blind (college catalogues, lecture notes, etc., in braille?). What should be done?

The purpose of this panel discussion is to, in general, address and discuss the issues involved in educating people with disabilities, particularly those that are not very obvious or visible (ex., wheelchair confinement). How should university campuses resolve this problem in this age of dwindling resources? Sensitive issues, such as “Needs of the many versus the needs of the few?” and “What responsibility do we have to the few that really need such assistance?”, also need to be resolved.
Core Principles of Human Factors Science
Authors: Smith Thomas J.
Published: January 2012

This report introduces three core principles that define human factors science, and summarizes conceptual and empirical evidence in support of their validity. The principles are: (1) performance and design are interdependent; (2) the unit of analysis is the human-machine system; and (3) tailor design to the control capabilities of behavior.
Limitations of Wrist Strength to Manual Exertion Capability in 2D Biomechanical Modeling
Authors: Al-Eisawi Khaled W. , Kerk Carter J. , Congleton Jerome J.
Published: January 2012

The objective of this study is to evaluate the assumption in biomechanical models that wrist strength does not limit manual exertion capability. An experiment was designed and run on right-handed males to test isometric elbow flexion strength at two included elbow angles: 90° and 135° and in two forearm positions: supinated and mid between supination and pronation. Isometric wrist flexion strength was also measured at the same elbow angles and at two wrist positions in the flexion/extension plane: neutral and 45° extended. Isometric wrist radial deviation strength was measured at the same two elbow angles and at two wrist positions in the radial/ulnar deviation plane: neutral and 30° ulnarly deviated. An equation was developed to calculate the theoretical minimum wrist strength limits for which wrist strength does not limit maximal moments about the elbow. These calculated limits were compared to the corresponding measured wrist strength moments. In general, wrist strength was found to be non-limiting, but in some specific circumstances, it can be limiting. Among the posture/exertion combinations tested, only wrist flexion strength in the extended wrist posture was found to be limiting. There was some evidence that strong-wrist people show less wrist strength limitations than weak-wrist people in some postures. It was also found that the neutral wrist posture is not associated with the highest wrist strength.
The Surface Area and Volume of the Hand
Authors: Mignano Bruce P. , Konz Stephan
Published: January 2012

This article recounts our research on measuring the surface area of the human hand. The surface area is measured using a photometric technique. The change in illuminance in a specially constructed and calibrated light chamber is measured when a hand is placed in the chamber. The hand is clad in a black dyed latex glove. An equation was developed to predict the surface area of the hand, using easy to obtain hand dimensions as independent variables. Regression analysis was used to determine the significance of the independent variables. The analysis yielded an equation that can predict the surface area of the hand, using easily measured characteristics of the hand.
Modelling the Additivity of Perceived Exertion in Symmetric, Mid-Sagittal Lifting
Authors: Lowe Brian D.
Published: January 2012

Psychophysical approaches to quantifying perceived effort have been used to evaluate the physical demand of many industrial work activities. An experiment was conducted to examine the relationship between ratings of whole-body perceived exertion and differentiated, regional ratings of exertion. The Borg, CR-10 scale was used by 16 subjects performing a simulated repetitive lifting task. Ratings of perceived exertion were obtained for the arms, legs, torso, and central (cardiorespiratory) effort sensations as well as a rating of overall, whole-body exertion. A multiple linear regression analysis was used to predict the whole-body rating of exertion from the differentiated ratings in lifting tasks using both a squat and stoop posture. In the stoop posture condition the coefficient of determination between whole-body perceived exertion and the model including arm, torso, and central ratings was R2=0.81. In the squat posture condition, the final regression model predicting whole-body exertion contained only the rating from the legs (R2 = 0.62). Differentiated ratings explained the majority of the variance in whole-body perceived exertion for squat and stoop lifting tasks.
Lessons Learned from a Retail Food Industry Ergonomics Task Force
Authors: Sluchak Thomas J.
Published: January 2012

Three individuals on the panel have participated in the formation and functioning of the Food Marketing Institute Ergonomics Task Force; the retailer on the panel has benefitted from the recommendations of the task force. The panelists will discuss lessons learned from the task force activity both for the retail food industry and for individual stores.
A Study of the Interaction between Load and Coupling during Lifting
Authors: Mirka Gary , Baker Ann , Harrison Angela , Kelaher Dan , Davis Joseph
Published: January 2012

The National Institute for Occupational Safety and Health (NIOSH) has increased the applicability of its lifting equation to a wider range of jobs by relaxing some of the simplifying assumptions of the original equation. Specifically, NIOSH has added an asymmetry factor and a coupling factor in the revised lifting equation. Two of the remaining simplifications, however, are that (1) interactions between terms are not considered and (2) the biomechanical analysis still utilizes a static modelling approach in its calculations. The purpose of the present research was to investigate the interaction between coupling and load magnitude under dynamic lifting conditions. Subjects lifted a box under various combinations of coupling and load. The dependent variables in this study were the peak external moment about the lumbosacral joint (as calculated by a dynamic biomechanical model) and the peak vertical ground reaction forces. The results show that at low levels of load there was little difference in peak torque across the different coupling conditions. However, when loads greater than 13.5 kg were combined with poor coupling, there was a fundamental change in the dynamics of the lifting motion. The results of this study indicate that the role of coupling under dynamic lifting conditions has both a perceptual and biomechanical effect which should be considered when designing manual materials handling tasks.
Integrating Ergonomics into the Rehabilitation Process: A Multi-Disciplinary Approach for Successful, Return-to-Work
Authors: Mayne Elizabeth A. , Sawyer Julie M.
Published: January 2012

This paper presents a system for successfully returning an injured employee to work through a multi-disciplinary approach. It details a process that interfaces physical and occupational therapists, rehabilitation specialists and ergonomists, among others. The aims of an effective and efficient occupational rehabilitation process are to ultimately reduce the societal costs of health care. The factors that contribute to these costs are many, and can be influenced by the behavior of the injured worker, the employer, the doctors and other health care providers. This paper discusses the complementary functions of the ergonomist and the therapist: the ergonomist, through workplace evaluation and redesign, considers the external factors that influence an individual's performance; the therapist evaluates and aims to improve the internal factors that affect an individual's performance. A match or mismatch between the physical demands of a job and an injured employee can then easily be detected by comparing the results of an ergonomic assessment and patient evaluation by a therapist. The authors conclude by discussing problems and benefits encountered through this approach.
Self Management of Rest Breaks by VDT Users
Authors: Henning Robert A. , Ortega Anna M. , Callaghan Eric A. , Kissel George V.
Published: January 2012

Video display terminal (VDT) users can benefit from frequent, short rest breaks in terms of improved productivity and well-being. However, VDT users report that scheduled breaks can seriously disrupt some tasks. This laboratory study tested if performance feedback would promote better self management of discretionary rest breaks. Undergraduate typists (N=31) entered lines of randomized words for 65 min. A mandatory rest break was administered whenever discretionary rest breaks did not total 30 s every 10 min. Typists in the experimental condition received feedback indicating how their discretionary breaks compared to a criterion. Typists in the control condition received no such feedback. Mood and musculoskeletal discomfort were assessed before and after the work period, followed by a questionnaire about the break system. Performance measures included keystroke rate, error rate, and correction rate (backspace use). Measures of heart rate and heart rate variability were also collected. Both the number of full-length mandatory breaks and correction rate were lower in the feedback condition. No significant differences in mood, musculoskeletal discomfort, physiological response, nor acceptance of the break system were found. These results suggest that self management of discretionary breaks as well as keystroke performance are improved by feedback, with no untoward effects on well-being.
Macroergonomics in the Context of Vendor-Customer Technology Transfer
Authors: Fisher Wayne
Published: January 2012

The transfer of a system-level product from vendor to customer typically requires that the customer change both business processes and organizational structures as part of the system implementation process. A macroergonomic approach was used to analyze the transfer of an image based check processing system to customer sites and identify opportunities to improve the transfer process. The analysis identified a lack of knowledge of the organizational, administrative and managerial changes that would be introduced by the new technology as a potential risk to the project implementation schedule. The analysis indicated that establishing a knowledge base covering five non-technical areas (general system familiarity, worksite preparation, human resources, operations and system support) and transferring that knowledge base to the customer's implementation team would minimize the potential schedule risk. A specialized consulting role was created to transfer the knowledge base to the customer's implementation team through a series of seminar sessions tied to specific implementation milestones. Each session focused on assisting the customer's implementation team in developing an action plan to allocate and schedule the resources necessary to carry the project through to the next milestone. The structure of the knowledge base and the presentation format for the consulting service were verified during initial trials at customer sites. A curriculum of classroom instruction and apprenticeship was then developed to train the consultants. Qualitative feedback from customers indicated that the service was perceived to provide value to the participants.
Analysis of Accident Data and Fatal Risk for Occupational Use of Extension Ladders
Authors: Wood Christine T. , McCarthy Roger L. , Padmanaban Jeya , Beyer Roman R.
Published: January 2012

This paper presents the results of analyses of injury and fatality accidents associated with the occupational use of metal extension ladders. Data contained in seven different data bases differing in geographic representation and level of severity of injury were analyzed to identify the type of accidents that occur and their frequency. In addition, the risks of fatality and of electrocution fatality associated with occupational use of extension ladders were estimated and compared with the fatal risk for various occupations. The overall fatal risk for extension ladder use by workers is less than the overall fatality risk for the construction industry.
Type form Variables: Differences in Perceived Readability and Perceived Hazardousness
Authors: Silver N. Clayton , Kline Paul B. , Braun Curt C.
Published: January 2012

This investigation assessed the type form variables that influence the readability of warnings and the subjective hazardousness of the product. The variables used were font type, point size contrast between the signal word and the main body of the warning (signal word-text size difference), and point size of the signal word. Fifty undergraduate students rated 36 insecticide labels that contained a warning which varied across all levels of the three variables. The composite variable “perceived readability” was formed from the averaged ratings from questions regarding readability and saliency. Another composite variable “perceived hazardousness” was formed by averaging the ratings of hazardousness of the product and carefulness in usage. Results for perceived readability and perceived hazardousness were analogous. Results showed that Century Schoolbook was perceived as more readable than Bookman or Helvetica. Moreover, greater perceived readability was obtained when there was no difference between the point sizes of the signal word and the body of the warning. Perceived readability and perceived hazardousness decreased as the signal word-text size difference increased. There was greater perceived readability and perceived hazardousness when the signal word was printed in 14-point type than in 12- or 10-point types. Implications for warning design are discussed.
Novice and Experienced Drivers' Looking Behavior and Primary Task Control While Doing a Secondary Task
Authors: Nieminen Tapio , Summala Heikki
Published: January 2012

This study is addressed to time-sharing and primary task control during a secondary task as a function of driving experience. After about 1.5 h of test driving, when well-adapted to the experimental car, 23 novices (less than 5,000 km of driving) and 26 experienced drivers (more than 150,000 km) were asked to change a cassette in a cassette player on an ordinary two-lane road. The task was replicated three times. The results showed no difference between novice and experienced drivers in time-sharing (glance length at the in-car task and at the road), lateral position-keeping (lateral displacement as a function of time at in-car task) or control in relation to oncoming traffic. The only difference occurred in speed control, experienced drivers keeping their speed level constant while novices slowed down somewhat during the secondary task. These data showed, in a supervised experimental setting, a similar linear relationship between time spent on an in-car task and lateral displacement both for novice and experienced drivers, and a similar median time gap of about 2 s to an oncoming vehicle at the moment when both novice and experienced drivers shifted their gaze from the in-car task to the road.
Simulator Evaluation of Road Signs and Signals
Authors: Allen R. Wade , Parseghian Zareh , Rosenthal Theodore J.
Published: January 2012

This paper describes a accuracy versus speed paradigm for evaluating signing and traffic signal conditions using low cost simulation technology. Two research examples are reviewed. One study involved the use of an interactive driving simulator that included the presentation of high resolution signs over the apparent viewing range from 500 to 50 feet. Drivers had to control vehicle speed and lane position while identifying the meaning of symbol signs as rapidly as possible. Subjects were scored in terms of correctness and the distance at which signs were identified. A second study involved a computer controlled presentation of static signalled intersection scenes, including supplemental signs, to subjects who were required to make decisions about permissive movements. Subjects were required to make decisions about permissive movements as rapidly as possible, and were scored by the computer on correctness and response time. Results in both studies showed that both response speed and correctness degrade with the complexity of signal and sign treatments.
RadView: A Preliminary Approach to Visualizing Occupational Radiation
Authors: Hoecker Douglas G. , Lloyd Timothy M. , Plantinga Harry
Published: January 2012

Visualizing three-dimensional distributions of radiation intensity, summed from multiple sources at a given work location inside a nuclear power plant, is a topic of interest to several prospective classes of worker in these plants. RadView is a concept for visualizing radiation that can be adapted to different users' applications once the core problem has been solved: how to effectively display this normally invisible phenomenon, while superposing the displayed data on the visually-cluttered environment that is typical of many work scenes. This demonstration presents the results of a preliminary feasibility study. At this stage, die results help more to clarify the problem than to propose a technical solution.