bluuebunny/crossref_metadata_2025 huggingface dataset:
Active Control versus Passive Observation in a Simulated Flight Task
Authors: Larish John F. , Andersen George J.
Published: January 2012

A study was conducted examining the effects of active control versus passive observation on the detection of changes in orientation in a simulated flight task. The subjects' task was either to fly through a simulated world by visual reference or to observe trials previously flown by another subject. During each trial the screen would go blank simulating flight into clouds. Following the blackout, subjects were required to correct any unexpected changes in orientation made during the blackout. These changes were equally divided between changes in pitch, roll, and translation along the line of sight. Furthermore, these changes were made in a direction that was either consistent or inconsistent with the direction of motion prior to the blackout onset. Although active controllers were more accurate than passive observers, these effects are mediated by the duration of blackouts, the type of change, and the consistency of changes. In particular, active observers were best at detecting changes that were relevant to the flight control task.
The Impact of Alternating between Integral and Separable Displays in a Multidimensional Decision-Making Task
Authors: Purcell Janine A. , Coury Bruce G.
Published: January 2012

Research into the format of visual displays of multidimensional data has revealed relative superiority of certain formats in relation to the nature of task demands such as fault diagnosis versus fault detection. Previous research also suggests that order of training or experience in working with alternate display formats might also influence the ability of operators to gain the full benefits of these display formats. This last factor comes into play during the redesign of existing displays and the design of multiple display environments in domains such as nuclear process control, tactical and commercial flight, and anesthesia monitoring.

The experiment described in this paper sought to further examine and clarify the types of performance decrements that can emerge after switching visual display formats used to support a complex decision-making task (Purcell and Coury, 1988). Accuracy and response time performance demonstrated that transfer of training was asymmetric after the switch. These results indicate that the order in which operators learn to use a given format of visually displayed data can enhance or hinder their subsequent use of alternate display formats. Redesign efforts and/or the use of multiple display formats in complex decision-making settings must address these effects.
Conformal Symbology, Attention Shifts, and the Head-Up Display
Authors: Wickens Christopher D. , Long Jeffry
Published: January 2012

Thirty-two pilots flew instrument approaches in a high-fidelity simulator. Location of flight symbology was manipulated head-up vs. head-down while controlling for optical distance and symbology format. Pilots were assigned to one of two symbology sets, conformal and non-conformal. Each pilot flew half of the trials with the symbology presented in a head-up location and half with the symbology located head-down. Airspeed tracking for both groups was displayed with non-conformal digital symbology. An unexpected far domain event was presented on one trial per pilot. The results revealed that, for flight path control, there was generally a cost associated with head-down location. The magnitude of this cost was larger for conformal than for non-conformal symbology. Head-up presentation resulted in faster transition from instrument to visual flight reference, but poorer airspeed tracking and slower response to the far domain unexpected event and greater error tracking digital airspeed. The results are interpreted with the theoretical framework of object-based and space-based theories of visual attention, and the tradeoffs between clutter of overlapping imagery and information access cost.
A Simulator Study of the Effect of Information Load and Datalink on Crew Error
Authors: Hrebec Dennis G. , Infield Susan E. , Rhodes Susan , Fiedler Fred E.
Published: January 2012

This study investigated the effects of air traffic control (ATC) induced information load and ATC communication modality on crew error in a fixed-base Boeing 747-400 flight deck simulator. To accomplish this, data from an experiment conducted by Boeing (Logan, et al., 1992) were re-analyzed. In this experiment, flightcrews engaged in two high-fidelity, full-mission scenarios. For this re-analysis, the variability in the amount of information ATC transmitted to the crew in the scheduled clearances was examined as an independent variable. To quantify this measure of information load, each scheduled ATC clearance was decomposed into mutually exclusive informational units called propositions. Each proposition consisted of one discrete “chunk” of information. On average, ATC clearances in the high information load condition contained more than two and a half times as many propositions as clearances in the low information load condition. Flightcrews made significantly more errors, and more errors per proposition, in the high information load condition than in the low information load condition. This indicates that it was the density of the information, or how many propositions were packed into each clearance, and not just the quantity of information which affected crew performance. Another manipulated variable was ATC communication modality. Each flightcrew participated in one scenario using a standard voice communications modality exclusively and in the other scenario using a combination of voice and digital DataLink. Though flightcrew error was significantly lower in the DataLink condition than the voice condition, this tendency was moderated by information load. In the low information load condition, flightcrews committed approximately the same number of errors in the voice and DataLink conditions, but in the high information load condition, flightcrews committed many more errors in the voice condition than the DataLink condition.
A Singular Value Decomposition Approach to Information Presentation Format Optimization
Authors: Miller Christopher A. , Morton Blaise
Published: January 2012

Glass cockpits pose a novel problem in Information Presentation Format (IPF) optimization since they invariably carry more formats than they can present any given time. In addition to optimizing individual formats and the static layout of sets of formats for information presentation, designers must now concern themselves with optimizing the overall set of formats from which a subset is drawn for presentation at any given time. Fortunately, quantitative knowledge representations and reasoning techniques, deriving primarily from research in the Pilot's Associate programs, enable the use of sophisticated mathematical analysis techniques for addressing this problem quickly and easily. We present initial work on the use of Singular Value Decomposition techniques for analyzing the “fit” between the information presenting capabilities of a set of IPFs and the information needs of a set of piloting tasks and show how this technique can be used to provide design recommendations for the global set of IPFs available for presentation in the cockpit.
Issues in Using Off-the-Shelf Pc-Based Flight Simulation for Research and Training: Historical Perspective, Current Solutions and Emerging Technologies
Authors: Beringer Dennis B.
Published: January 2012

Flight simulation has historically been an expensive proposition, particularly if out-the-window views were desired. Advances in computer technology have allowed a modular, off-the-shelf flight simulation (based on 80486 processors) to be assembled that has been adapted, with minimal effort, for conducting general-aviation research. This simulation includes variable flight instrumentation, forward, 45 and 90 degree left external world views, and a map display. Control inputs are provided by high-fidelity analog controls (e.g., damped and self-centering yoke, high-performance throttle quadrant, gear, flap, and trim controls; and navigation radio frequency select). The simulation is based upon two commercially available flight simulation software packages, one designed as an instrument flight trainer and the other as a “game”-type flight simulation. The provisions of these packages are discussed highlighting their particular research capabilities as well as their limitations. The comparatively low cost and ease of assembly/integration allow multiple “standardized” systems to be distributed for cooperative interlaboratory studies. The approach appears to have utility for both research and training. Preliminary experimental results are reported as a validation of the utility of the system for research.
Human Factors and Ergonomics in Maintenance and Inspection Symposium Abstract
Authors: Shepherd William T.
Published: January 2012

In 1991 the National Plan for Aviation Human Factors was published. The plan proposed a variety of research priorities for the nation's aviation industry and government entities. The FAA Office of Aviation Medicine has been conducting a research program to address the Aviation Maintenance topics identified as significant in the National Plan. The resultant research program has been recognized as the most significant maintenance-oriented human factors study in the world.
Reach Design Data for the Elderly
Authors: Wright Ursula , Kumar G. Major , Mital Anil
Published: January 2012

The increased life expectancy of the elderly may require substantial redesigning of environments in order to accommodate age related body changes. One of the most important aspects allowing the elderly to function independently is the ability to reach for items comfortably during daily activities. Designing for an independent elder requires knowledge of reach measurements that determines the optimal design of working/living environments. This paper provides reach capability design data of elderly males and females between 65 and 89 years of age. Results show that direct and indirect reach indicators decrease substantially above the age of 80. The elderly participating in this study were compared with younger cohorts, showing significantly lower reach capabilities. This indicates the necessity of considering anthropometric data, such as reach, to design for the elderly. The need is particularly dire for those above 80 years of age.
Age Similarities in Complex Memory Search: An Extension of Dual Process Theory
Authors: Cooper Brian P. , Fisk Arthur D.
Published: January 2012

Understanding age-related similarities and differences in development of cognitive skill is important as it can inform theories of cognitive aging as well as serve the pragmatic value of informing those individuals who are developing age-related interventions for numerous activities of daily living. We investigated both the performance and learning of skilled memory search, a task that has shown age-related similarity in performance if sufficient consistent practice is provided, to determine if training guidelines for this class of processing activities is applicable to both young and old adults. Old and young adults received memory search training, and then the participants were transferred to untrained exemplars of the trained memory set categories. The results suggest that both young and old adults are, at least to some extent, learning at the semantic-category level. This study provides additional evidence that training guidelines derived from an automatic and controlled processing framework can be applied to an older adult population in tasks which have memory search components.
Symposium Analysis and Modeling of Use of Procedures in Dynamic Worlds: Implications for the Design of Computer-Based Procedures
Authors: Roth Emilie M. , Corker Kevin M.
Published: January 2012

In dynamic high risk environments, such as aviation, air traffic control, and nuclear power plant operations, when emergencies arise, the burden of diagnosing and developing a response strategy in real time can be very high. One response to this problem that has been adopted in a number of domains is to develop preplanned response strategies in the form of procedures that the person-on-the-scene is expected to follow in dealing with the emergency. This symposium examines the cognitive demands inherent in responding to emergencies when procedures are available, and the implications for development of computer-based procedures and related decision-support systems.

The four papers examine procedure-supported performance from different perspectives. Three of the papers directly compare operator performance in simulated emergencies using paper-based procedures with operator performance using prototypes of computer-based procedures. The paper by Converse, reports an empirical study comparing operator performance using these two modes of support. The papers by Laughery and Persensky and Hoecker, Corker, Roth, Lipner and Bunzo examine the use of simulation models of operator performance as engineering tools for predicting the effect of computer-based procedures on operator performance. All three papers point to ways in which computer-based procedures facilitate operator performance and ways in which they impose new demands. The fourth paper, by Roth, investigates operator performance in more complex simulated emergencies that are not fully addressed by the procedures. The paper describes the cognitive activities required of operators to recognize and deal with situations that go beyond the available procedural guidance, and discusses implications for the design of computerized procedures and related decision support systems.
Man-Machine Design and Analysis System (MIDAS) Applied to a Computer-Based Procedure-Aiding System
Authors: Hoecker Douglas G. , Corker Kevin M. , Roth Emilie M. , Lipner Melvin H. , Bunzo Marilyn S.
Published: January 2012

Difficult issues in design criteria confront the designers of human—computer interaction (HCI) implementations for future power plant control rooms. Such HCI-intensive control—room elements include “soft” controls and displays, computerized procedures, alarm presentations, and support for cooperative information—sharing among crewmembers. This shift in technology, from dedicated controls and displays in fixed locations to multifunction computer—driven operator workstations and wall displays, must focus not only on the required functionality of these interfaces, but also on their crafting and integration in such a way as to minimize the likelihood of operator error.

With the objective of providing early insight into the cognitively error—prone consequences of selected interface dynamics, we are adapting a computer—based cognitive modeling tool, the Man—machine Integrated Design and Analysis System (MIDAS), to quantitatively model certain user requirements for operating different types of interfaces while dealing with high—consequence events in a control room setting. MIDAS was conceived and is being developed as a joint Army/NASA program at the NASA Ames Research Center to test different design approaches to computerizing the cockpits of advanced commercial and military aircraft.

This report presents preliminary results from a project to adapt the MIDAS tool to the nuclear control room domain. These results have enabled comparative observation of cognitive loading depending on whether a supervisor uses computerized procedures or paper procedures to direct crew response to a plant trip event. The results suggest that each technology for procedural support, in its current respective implementation, has its own strengths and weaknesses at different points in the control task dialog.
Operator Performance in Cognitively Complex Simulated Emergencies; Implications for Computer-Based Support Systems
Authors: Roth Emilie M.
Published: January 2012

An empirical study was conducted examining operator performance in cognitively demanding simulated nuclear power plant emergencies. During emergencies operators follow highly prescriptive written procedures. The objectives of the study were to understand and document what role higher-level cognitive activities such as diagnosis, or more generally ‘situation assessment,’ play in guiding operator performance, given that operators utilize procedures in responding to the events. The study examined crew performance in two simulated emergencies. Up to 11 crews from each of two plants participated in two simulated emergencies for a total of 38 cases analyzed. Crew performance was videotaped and partial transcripts were produced and analyzed. The results revealed a number of instances where higher-level cognitive activities such as situation assessment and response planning enabled operators to handle aspects of the situation that were not fully addressed by the procedures. This paper describes these cases and discusses their implications for the design of computer-based support systems.
Operating Procedures: Do they Reduce Operator Errors?
Authors: Converse Sharolyn A.
Published: January 2012

Computerized operating procedures have been suggested as a mechanism for reducing human error in nuclear power plants. The Computerized Procedures Manual (COPMA-II) is an electronic procedure system that can be used to execute procedures, to track progress through plant procedures, and to automatically monitor plant parameters. To evaluate the effectiveness of COPMA-II, eight teams of two licensed reactor operators operated a scaled pressurized water reactor under normal and accident conditions, using both COPMA-II and traditional paper procedures. Error rates, times to initiate procedures, times to complete procedures, and subjective estimates of workload were collected for each scenario. The most interesting finding of the study was that, for one accident scenario, performance with COPMA-II was twice as accurate as performance with paper procedures. However, operators initiated responses to both accident scenarios fastest with paper procedures. Procedure type did not moderate time to complete procedures.
Cooperative Communications in Dynamic Fault Management
Authors: Johannesen Leila J. , Cook Richard I. , Woods David D.
Published: January 2012

The motivation for this research is to further theory on the development of artificial intelligence systems that function as “team players” in dynamic fault management applications. One challenge is effectively supporting the practitioner in understanding the assessments and actions of the intelligent system. The typical expert system approach to explanations is not well suited to the cognitive demands of dynamic fault management. In order to gain insight into effective cooperative interaction in dynamic fault management, we have undertaken a field of study of practitioners in one such domain, anesthesiology. We analyze the findings using the theoretical framework of a common ground and common frame of reference.
Relative Effects of Color-, Texture-, and Density-Coding on Visual Search Performance and Subjective Preference
Authors: Perlman Gary , Swan J. Edward
Published: January 2012

Previously, it had been found that texture-coding was ineffective at reducing search time (Perlman & Swan, 1993). In the experiment reported here, 16 subjects searched for blank-, color-, texture-, and density-coded targets of varying complexity in a naturalistic task. The data showed that all non-blank methods were significantly and about equally more effective at reducing search time than blank-coding (no coding). The difference of outcome with previous results is explained by task simplification and by the control of possibly confounding factors. The difference suggests that coding techniques using texture, and possibly other methods, should be evaluated in context. The similar performance of color-, texture-, and density-coding is explained by the use of equal-saturation and equal-brightness colors. Recommendations for the design of effective coding methods and for future research are discussed.
Visual Analysis of Scientific Data: Comparison of 3D-Topographic, Color and Gray Scale Displays in a Feature Detection Task
Authors: Merwin David H. , Vincow Michelle A. , Wickens Christopher D.
Published: January 2012

Several display techniques were compared for representing scientific data in the context of a feature detection task. The data sets were rendered on a Silicon Graphics workstation using four display formats: linearized gray scale; rainbow scale; reduced hue (blue-green-yellow-white) scale; and a 3D-topographic format viewed in stereo. The task involved searching for features that were embedded in scientific data sets consisting of two spatial and one scalar variable. Data sets were drawn from three scientific domains: Landsat, medical MRI, and global atmospheric data bases. Two types of features were embedded within the data sets: circular (blob-like) discontinuities, and linear (cliff-like) discontinuities. Results showed a general advantage for the gray scale, and a marked disadvantage for the 3D-topographic format in both accuracy and response latency. Performance in the two color scale formats was intermediate, with the reduced hue scale supporting faster, if not more accurate performance than the full rainbow scale. Performance differences were found across data base domains, as well. Directions for future research are discussed.
Asymmetrical Spatial Accuracy in 3D Tracking
Authors: Zhai Shumin , Milgram Paul
Published: January 2012

This paper reports on asymmetrical spatial accuracy of human subjects in tracking of an object which moves randomly with 6 degrees-of-freedom (DOF) in a 3D environment. It was found that, for translational errors, RMS deviations in the depth (Z) direction were 40% higher than those in the horizontal (X) direction, for an experimental display which provided binocular disparity (stereopsis), perspective and partial occlusion cues. In general, translational tracking errors in the vertical (Y) direction were greater than those in the X direction and smaller than those in the Z direction. In early stages of practice, vertical errors were similar to those in the Z direction, but as learning progressed, errors in the X and Y dimensions converged. These finding were consistent across two types of controllers and different tracking paths in the 3D environment. It would appear that horizontal movement requires higher attentional resource priority over vertical movement in such a tracking task.
Investigation of Errors in Perception of Stereoscopically Presented Virtual Object Locations in Real Display Space
Authors: Utsumi Akira , Milgram Paul , Takemura Haruo , Kishino Fumio
Published: January 2012

This paper describes studies on perception of virtual object locations. It explores the behavior of some factors related to depth perception, especially the effect of inter-pupillary distance (IPD) mismatch and the interplay of image blur and binocular disparity. IPD mismatch (which is caused by errors in estimation of the parameter) results in a certain perceptual error of virtual objects' depth. Blur of images is also a source of error in depth representation. It was found, in some cases, to be a very strong depth cue. The results of a series of experiments conducted on IPD mismatch and image blur are also presented.
Cognitive Psychophysics and Mental Models
Authors: Gillan Douglas J.
Published: January 2012

With the increased emphasis on incorporating users' mental models in design of interfaces comes an increased need for instruments for measuring mental models. Two frequently-used instruments for measuring people's mental representations of physical space are drawing a map and rating the distances between pairs of points in the space. The assumption underlying the present research was that mental representations of space (M i) are transformed to become a subject's response (R i), yielding the following functions: Rdraw i = frd(M i) + e d (for drawing a map), Rrate i = fr(M i) + e r (for making category ratings), and Rnavigate i = fn(M i) + e n (for navigating). If each of these functions were equivalent, then the correlations among the different measurement methods should be high. Subjects either drew maps in two sessions, provided category ratings of the distances between pairs of locations in two sessions, or drew maps in one session and rated distances in a second session. The correlations were significantly lower when subjects switched between rating and drawing than when they performed the same response in both sessions. These data suggest that the functions relating the mental representation to a response differ between drawing and rating. The discussion focuses on methods for measuring mental maps and the use of mental map data in designing spatial interfaces (including interfaces to information spaces).
Frame of Reference in Posture Specification for Computer-Aided Ergonomic Analysis
Authors: Zhang Xudong , Liu Yili , Chaffin Don
Published: January 2012

An experiment was conducted to examine the effect of the congruency between the reference frame adopted to perceive and record postures and the one employed in a computer-aided ergonomics software on human posture specification performance. The role that the interface can play in enhancing the congruency was also investigated. The subjects were presented with the photographs of a working posture, and were required to manipulate the human stick figures generated by the ergonomics software to match the posture in the photographs. The experiment showed that the congruency played a significant role in facilitating the performance of posture specification for ergonomic analysis. It also demonstrated a clear advantage of using a 3-D humanoid display to improve the congruency when it is not achievable in the pre-analysis posture data-collection. Implications for ergonomic job analysis and ergonomics software design are discussed.
User Interface Design Guidelines for Computer Accessibility by Mentally Retarded Adults
Authors: Robertson Gretchen L. , Hix Deborah
Published: January 2012

An exploratory three-phase study examined the ability of adults diagnosed as moderately developmentally disabled to successfully use a personal computer, input devices preferred, and user interface design factors to be considered when designing or selecting applications for this population. Phase I observed the reaction of the participants, none of whom had ever used a computer, to a graphical user interface. In Phase II usability tests compared the mouse, the trackball, and the touchscreen to gather heuristic data on input device preference and develop user interface design guidelines for applications for the target population. Phase III tested the guidelines by developing two prototype games: “Shopping,” designed to teach money-handling skills, and “Getting Dressed,” to teach a basic life skill. Phase I showed that participants liked and understood the graphical user interface. All could use the touchscreen, and most could use the mouse. Phase II usability testing found that the mouse was preferred over the touchscreen and the trackball, although its drag-drop times were longer. Reasons given were less fatigue and greater control. Phase III found participants preferred screens that allowed them to control the action, that quick or unexpected screen responses were upsetting, and that strong, realistic visual feedback was important. The study is seen as a first step in developing guidelines to make the computer accessible to those with moderate developmental disability.
The User Interface Design Process: The Good, the Bad, & we did What we Could in Two Weeks
Authors: Miller Marta A. , Stimart Reynold P.
Published: January 2012

Conventional wisdom inside human factors circles says that the integration of user interface design processes into the software development cycle is the best way to improve the usability of software products. While there is no problem convincing human factors practitioners of this, frequently there is still a need to demonstrate the effectiveness of user interface processes to product development teams and management. Mayhew (1992) suggests that it is not enough to be able to apply human factors knowledge. Successful user interface design must include buy-in from outside of the user interface organization. To demonstrate the effectiveness of a user interface design program, data from usability tests on three versions of a product were analyzed. The oldest version of the product was developed without the inclusion of any user interface design processes. The second version of the product had minimal involvement of user interface practitioners late in the development cycle. The newest version of the product was developed with the user interface design processes fully integrated into the software development cycle. The data indicate that user interface design processes do impact usability, as measured by speed, accuracy, and subjective measures. Furthermore, user interface processes which are part of the software development cycle, as opposed to just a side effort by user interface practitioners, seem to have a much greater impact on usability.
Navigation in the Computer Medium: A Cognitive Analysis
Authors: Watts Jennifer
Published: January 2012

The goal of this research is to provide a cognitive analysis of navigation in the computer medium. As the complexity of computerized information systems increases, interface designers face the formidable challenge of supporting navigation within these systems to allow users to quickly obtain information relevant to their tasks and goals. Instead of focusing solely on the comparison of a small subset of proposed techniques or theories for aiding navigation, this study investigates how people handle navigation within the natural context of a familiar computer environment, and reveals processes that can be better supported in order to aid navigation. Both a field study and a field experiment were conducted. The results of these studies provide evidence to support previous navigation-related theories and contribute to a pattern of navigation behavior that has been observed in other domains like anesthesiology and nuclear power. In addition to describing the characteristics of the computer medium that influence people's ability to navigate, this paper will also discuss typical navigation problems that arise in this medium, and how people change their behavior and adapt to computer systems to overcome these problems.
Differences in Behavioral Compliance as a Function of Warning Color
Authors: Braun Curt C. , Greeno Brian , Silver N. Clayton
Published: January 2012

A body of literature asserts color's influence on display preference, cognition, behavior, and performance. Although these results have clear implications for the design of consumer product warnings, color has been disproportionately underrepresented in warnings research. The present study examined the effect of color on compliance with printed warnings. Sixty-five undergraduates interacted with a pool water test kit and a two-part adhesive. The warning on each product was factorial for color (i.e., red, green, and black) and was constant for content. Participants indicated a higher likelihood of injury associated with products printed in red than green or black. Behavioral compliance was assessed by indicating if subjects donned protective gloves as directed by the warning. The data indicated that warnings printed in red resulted in a higher proportion of compliant behavior than green and black combined.
Product Label List Format: Effects of Item Arrangement and Completeness on Comparison Time and Accuracy
Authors: Wogalter Michael S. , Kalsher Michael J.
Published: January 2012

This research examined the influence of two factors on the ease of gaining information from item lists: the order and completeness of the items displayed. Food nutrition labels served as the vehicle to test the manipulated lists on comparison time and accuracy performance measures. Four booklets, each containing 12 pairs of nutrient labels, were constructed in which the listed items were: (1) either arranged in a standard order or in a random order, and (2) either had a complete set of nutrients (including nutrients not present in the product) or a partial set of nutrients (excluding nutrients with zero or near-zero amounts in the product). Thirty-two participants were instructed to assume that their physician has told them to increase their intake of three specific nutrients and decrease their intake of three other nutrients. One label of each pair contained a higher level of one nutrient that should be increased or a lower level of one nutrient that should be decreased. Participants were to determine which of the two labels would be better given the prescribed diet. Time and accuracy measures were collected. Participants made significantly faster judgments for nutrients arranged in a standard order than for nutrients arranged in a random order. For all conditions, the error rate was low. An interaction indicated that labels with a complete set of nutrients in a standard order produced fewer errors than (a) labels in a standard order with some nutrients missing or (b) labels with a complete set of nutrients in a random order. Implications of making lists compatible with expectations are described.
Ethical Issues Related to the Use of Humans in Human Factors and Ergonomics
Authors: Moroney William F.
Published: January 2012

As professionals, we must be aware of our ethical responsibilities when engaged in research and testing. The purpose of this paper is threefold: 1) to increase the reader's awareness of some of the issues specific to our discipline, 2) to provide some guidelines and references regarding the use of human subjects, and 3) to increase the dialog in this critical area. The material discussed focuses on Federal Regulations related to the protection of human subjects. The changing role of the human subject from “research material” to “participant partners” is also discussed.
Integrated Job Design in the Introductory Human Factors Course
Authors: Freivalds Andris , Goldberg Joseph H.
Published: January 2012

Two different workstations are being utilized in the introductory human factors course: a workstation appropriate for typical blue-collar assembly work and a workstation appropriate for white-collar computer driven work. The white-collar workstation simulates a modern computer driven office job, with different factors influencing its productivity, such as speed, accuracy, noise, illumination, etc. The blue-collar workstation is centered around a typical carburetor assembly process found in the U.S. automotive industry. This is especially appropriate because of the large number of fairly intricate parts, the highly repetitive and rapid assembly process, and the need for power driven tools. These also happen to be the prime factors that are thought to increase the incidence of cumulative trauma disorders in U.S. industry. The students examine various tool parameters and are able to adjust the support of the tool with tool balancers, cut the detrimental impact of power tools on the hand, using the reaction torque bars and implement novel approaches, such as arm rests or arm slings as used in Sweden. Such an approach allows for the integration of traditional industrial engineering concepts with more modern human factors theory, for the ‘solving’ of open-ended problems and provides students with real-world applications.
Work System and Job Design Factors in Preventing Wmsds in VDT Operators
Authors: Hendrick Hal W.
Published: January 2012

Recent research is reviewed which indicates conventional work station design ergonomics is insufficient, by itself, to prevent WMSDs in typical VDT jobs; and that work system design and related psychosocial variables appear critical. Three common system design practices are cited as the basis for the widespread poor design of VDT work systems and jobs. Macroergonomics is proposed as a work system and job design approach that circumvents the deficiencies of these three common design practices. Specific job design factors from the literature are identified.
A Viewpoint on Professional Conduct for Ergonomic Experts in Forensics
Authors: Smith Leighton L. , Rudov Melvin H. , Dingus Thomas , Pauls Jake , Staffo Gary T.
Published: January 2012

This panel session explores the paradigm of professional conduct for ergonomic experts in the practice of forensics. A hypothesis of conduct is offered as a candidate guideline for professional conduct. This hypothesis is based on basic professionalism principles and has been adapted on the basis of observed experiences in the field, comments from other practicing professionals, and in the context of previous draft “codes” of professional conduct for human factors professionals and also for ergonomic forensics practitioners. The panelist contributions to this session range from a discussion of the need for and merits of a standard of professional conduct, to institutionalization of standards or codes of conduct, to the breadth and scope of professional involvement in forensics, to the mechanics of the actual practice of professional ergonomie forensics, to a comparative perspective from the related discipline of safety.
Influences on Ratings of Risk for Consumer Products
Authors: Leonard S. David , Cummings J. Bradley
Published: January 2012

Previous studies have suggested many persons do not know the meanings of many terms commonly used as stand alone descriptions of hazards. Studies (Leonard & Digby, 1992; Leonard & Hill, 1993) have shown that the same hazard description, for example flammable, associated with different products resulted in very different perceptions of risk. The present study eliminated anchoring effects that may have resulted from using separate categories by combining 13 different products into a single set for both rating and ranking. The results were consonant with previous findings in that a low correlation between subjective impressions and physical characteristics was found. Subjects in a second study who received a demonstration of some of the products' flammability significantly changed their ratings. The discussion involved consideration of how cognitive information may be developed.
Movement Times of Right and Left Handers Using Preferred and Non-Preferred Hands
Authors: Hoffmann Errol R.
Published: January 2012

The aim of the present work was to quantify the difference in performance of hands when doing tasks of defined difficulty. Results of five experiments are reported in which strongly lateralised subjects performed movement tasks with their preferred and non-preferred hands. These tasks were (i) ballistic movements (ii) Fitts' task (iii) pin-to-hole transfer (iv) Drury tracking task (v) a modified form of the Drury tracking task in which subjects cut paper with scissors. The results showed that in ballistic tasks there was no significant effect of handedness or of hand used. With visually-controlled tasks, where there was considerable control of accuracy required, the preferred hand generally performed better than the non-preferred hand. There was however no significant difference, in any of the tests, between right and left handers when using their preferred hands. Left handers, in some tasks, performed better with their non-preferred hands than did right handed persons using the non-preferred hand.
A Methodology for Investigating Heat Stress Selectivity Effects on Mental Performance
Authors: Vasmatzidis Ioannis , Schlegel Robert E.
Published: January 2012

This paper outlines a methodology that can be used to investigate the selectivity patterns of heat stress effects. The adopted view is that heat stress causes performance to deteriorate because it depletes attentional resources. The term “selectivity” refers to the extent to which certain individual resource pools (the existence of which is postulated by multiple resource theories) are more susceptible to heat stress effects than others. The methodology consists of plotting performance of two time-shared tasks over time on the Performance Operating Characteristic (POC) space. Manipulating the difficulties of the paired tasks under the same environmental conditions (i.e., temperature level and exposure duration) produces a predictable change of the POC path. In particular, if the heat stress effects are non-selective, the POC path will rotate either clockwise or counter-clockwise depending on the task whose difficulty is increased. On the contrary, if the heat stress effects are selective, increasing the difficulty of a task will have no effect on the orientation of the POC path.
Evaluation of Crew Capabilities to Handle and Stabilize Heavy Masses in Microgravity
Authors: Rajulu Sudhakar L. , Klute Glenn K. , Wilmington Robert P.
Published: January 2012

One of the purposes of NASA's Shuttle missions is to deploy and retrieve satellites. Some of these missions require extravehicular activities (EVAs). During EVAs, crew members wear pressurized suits for protection from hazardous conditions and use a Remote Manipulator System (RMS) to transfer heavy objects from one location to another. Prior to the Hubble Space Telescope repair mission (STS-61), concerns were raised whether crew members would be able to hold onto the modules if the RMS started or stopped unexpectedly. An experiment was conducted to measure the handle forces during such a scenario and to determine whether these forces and moments were well within the capabilities of the crew. Four subjects participated in the study. Mockups were built to represent the characteristics of the actual unit and tests were conducted at the Precision Air Bearing Facility (PABF) which simulates a nearly friction-free environment. Force plates were attached to the mockups to monitor forces and moments during the test. Controlled translation and rotation tasks were also conducted to compare the results with those of sudden RMS run start/stop tasks. The results from this study showed that the forces and moments exerted by subjects during sudden stopping and starting conditions were well within the capabilities of the crew members. This study thus provided quantitative data for NASA to be assured of a safe and successful mission.
Influence of a Pitch Adjustable Foot Restraint on Operator Induced Loads in Zero-Gravity
Authors: Wilmington Robert P. , Poliner Jeffrey , Klute Glenn K.
Published: January 2012

The zero-gravity environment creates a need for a proper human body restraint system to maintain a comfortable posture which lessens fatigue and maximizes productivity. In addition, restraint systems must be able to meet the loading demands of maintenance and assembly tasks performed on-orbit. The Shuttle's primary intravehicular astronaut restraint system is currently a foot loop design that attaches to flat surfaces. This restraint system allows for variation in mounting locations and ease of ingress and egress. However, this design limits performance because it does not allow for elevation, pitch, or foot loop length adjustment. Several prototype foot restraint systems are being evaluated for use aboard Space Station and the Space Shuttle. A study was initiated using NASA's reduced gravity aircraft quantifying differences observed in operator performance while adjusting the pitch angle of a prototype foot restraint. Pitch angle adjustments were made from 5° to 35°. While operators performed a torque wrench task using a hand hold and foot restraint, the maximum axial forces and moments induced on the restraint systems and torque wrench were recorded. Overall this study did not see any significant difference in the force operators could place on the torque wrench or forces imparted to the foot restraint system due to the pitch orientation of the foot restraint. Thus in a work environment in which hand holds are available, no significant influence of the pitch angle existed for operator performance or forces imparted to the restraint system.
Relationships between the NIOSH (1991) Lifting Index, Compressive and Shear Forces on the Lumbosacral Joint, and Low Back Injury Incidence Rate Based on Industrial Field Study
Authors: Karwowski Waldemar , Caldwell Marenda , Gaddie Paul
Published: January 2012

The main objective of this study was to investigate relationships between the values of NIOSH (1991) Lifting Index calculated for as set of industrial manual handling tasks, the corresponding (estimated) compressive and shear forces on the lumbosacral joint (L5/S1), and the back injury incidence rates based on analysis of the epidemiological field data. A strong positive correlation was observed between the estimated compressive forces on L5/S1 and the lifting index (LI) values, and between the incidence rates (IR) of low back injury and the LI index. Two sets of regression models describing the relationships between the lifting index (LI) and the compressive forces on the L5/S1 were developed. It was shown that the LI=1.0 corresponds to about 1.8 kN and 2.4 N of compression on the L5/S1, for the destination and origin of the lift, respectively. For the lumbar compressive strength values (with safety factor of one standard deviation) of 4.1 kN for males (40 years of age), proposed by Jager and Luttman (1992), the corresponding values of the lifting index are as follows: LI=4.1 (for the lift destination) and 6.4 (for the lift origin). Implications of results for prevention of back injury due to manual lifting were discussed.
Age Effects in Biomechanical Modeling of Static Lifting Strengths
Authors: Chaffin Don B. , Woolley Charles B. , Buhr Trina , Verbrugge Lois
Published: January 2012

There is growing awareness that age results in reduced strengths in the population, and that significant decreases start in the 5th decade. The magnitude of the decrease in strength depends on the specific muscle function being tested. Because of differential effects it is not clear how various decreases could alter whole-body strength performance. This paper describes how specific strength decreases measured in an older population of men and women could affect their whole-body exertion capabilities in selected scenarios. A computerized strength prediction program is used to both predict the whole-body strength changes with age, and to study how older populations can alter their postures to achieve maximum exertion capability. The results indicate that different muscle group strengths decline by 5% to 70% with age, depending on which muscle group is tested. These changes have profound effects on whole-body exertion capabilities, which also are shown to depend on specific postures used to perform the exertions.
Contact Area Effects on Discomfort
Authors: Goonetilleke Ravindra S. , Eng Timothy J.
Published: January 2012

Most “ergonomic” products attempt to adopt a uniform force distribution strategy to improve comfort. The rationale being that force distribution over a large area reduces pressure and thereby enhances user comfort. However, sensory literature alludes to the concept of spatial summation, i.e. greater sensation by stimulating a larger surface area. Hence spatial summation would tend to suggest a greater discomfort when forces are applied over large surface areas. This study reports the effect of surface area on maximum discomfort causing pressure or maximum pressure tolerance (MPT). Two circular probes of different cross sectional area were used to stimulate the skin surface. The mean MPT with a probe of 5mm diameter was 3.3 times higher than the MPT with a probe of 13mm diameter. These findings suggest the following:

• Perceived discomfort and contact area seem to have a “U-relationship” above a critical force value. Traditional thinking of distributing forces is successful only in the first half of the U-curve or with forces below the critical value. The section with the monotonically increasing relationship between discomfort and contact area (i.e., second half of U) may not be seen at very low forces or forces below the critical value. • “High” pressures in concentrated areas may cause less discomfort than “moderate” pressures over a larger area. • The critical or threshold pressure to induce discomfort is force and contact area dependent.