bluuebunny/crossref_metadata_2025 huggingface dataset:
Maximum Safe Weight of Lift: A New Paradigm for Setting Design Limits in Manual Lifting Tasks Based on the Psychophysical Approach
Authors: Karwowski Waldemar
Published: January 2012

The main objective of this study was to introduce a new concept for setting design limits in manual lifting tasks, i.e., the notion of the maximum safe weight of lift (MSWL), and to examine the effects of different sets of subject instructions for load selection on the amount of weight determined by male subjects in the psychophysical experiment. The results revealed that the MSWL values were significantly lower than the maximum acceptable weight of lift (MAWL) values. It was proposed that the classical approach to setting design limits in manual lifting tasks, based on the psychophysical method introduced by S. Snook, be modified to emphasize the subjects' safety and to reduce the risk of musculoskeletal injury.
Changes in wrist postures during a prolonged typing task
Authors: Honan M , Jacobson M , Tal R , Rempel D
Published: January 2012

Twenty experienced typists participated in a laboratory based study to determine whether wrist and forearm postures changed over a 4 hour period of intensive keyboard use. Subjects were randomly assigned to use a conventional keyboard or a fixed split keyboard. Posture data was acquired using electrogoniometers after a 10 warm-up period and at the end of each hour. Wrist and forearm postures did not change significantly over the four hour period among subjects using the split geometry keyboard. On the conventional keyboard, all joint postures were stable except right wrist extension and left forearm pronation. The right wrist extension increased by 5° over the four hour period (p=.002) and left pronation decreased by approximately 9° (p=.001). Wrist postures among typists exposed for the first time to a split keyboard remained constant throughout a four hour period of intensive typing. On the conventional keyboard, some postures drifted over the four hour period.
Ergonomic Evaluation of Keyboard and Mouse Tray Designs
Authors: Paul Rajendra , Nair Chandra
Published: January 2012

Surface electromyography and electrogoniometry were used to evaluate four designs of keyboard and mouse trays. The four designs were: winged design, sliding design, two-tier design and combination of a keyboard tray and a mouse tray. For comparison, data were also collected with the keyboard and mouse placed on a plain work surface. Eight subjects, four male and four female, evaluated the designs in random order while performing a word processing task. Subjects' working postures were recorded using a high-resolution video camera. Body part discomfort was evaluated using the Corlett scale. The subjective and objective results suggested that the sliding design and the two-tier design performed better than the other two designs. The work surface performed inferior to all four keyboard and mouse tray designs. Since mouse input devices are widespread in modern offices, this study could provide some useful information to practicing ergonomics, health and safety professionals.
Three-Dimensional Spinal Loading during Complex Lifting Tasks
Authors: Fathallah Fadi A. , Marras William S. , Parnianpour Mohamad
Published: January 2012

Knowledge of the complex three-dimensional loads imposed on the spine during typical manual materials handling (MMH) tasks could provide more insights about the mechanical etiology of low back injuries in occupational settings. Comprehensive treatment of such information has been lacking. Most previous studies quantified spinal loading in terms of compressive forces alone. However, there is enough empirical and epidemiological evidence to indicate that the shear forces imposed on the spine may be more important than mere compression. Hence, the purpose of this study was to assess, in-vivo, the three-dimensional complex spinal loading associated with lifting tasks. Subjects performed simulated lifting tasks with varying workplace characteristic. An EMG-assisted model provided the continuous three-dimensional spinal loads. Asymmetric (complex) lifting tasks showed distinctive loading patterns from those observed under symmetric conditions. Simultaneous occurrences of spinal loads in all three directions (compression and shear forces) were patterns unique under the “risky” asymmetric lifting conditions. These situations could be identified and abated through proper workplace design. In conclusion, this approach allow the determination of the magnitudes and temporal occurrence(s) of complex spinal loading, and assess the sensitivity of these loading patterns to workplace characteristics.
The Effects of Glove Frictional Characteristics and Load on Grasp Force and Grasp Control
Authors: Bronkema-Orr Lisa , Bishu Ram R.
Published: January 2012

The objective of this experiment was to determine the effect of varying levels of glove surface friction, glove type, and various loads lifted on submaximal holding performance. The independent variables were glove type, friction level, load lifted, trial, and gender. Ten males and ten females performed two trials of lifting a device similar to a standard hand dynamometer under each of these conditions. All the main effects were significant at the 0.0001 level for the dependent variables of stable force and peak force. The results indicate that the surface friction of a glove affects the amount of force with which the subject feels he needs to grasp an object. In addition, the amount of force exerted per pound lifted decreased with increasing weights, perhaps indicating over exertion at the lighter levels of the weight lifted, or under exertion at the higher levels of load.
Gender, Grip Span, Anthropometric Dimensions, and Time Effects on Grip Strength and Discomfort
Authors: Pazderka M. Peggy , Henderson Melissa , Hallbeck M. Susan
Published: January 2012

The objective of this study is to examine the relationship among anthropometric dimensions, grip span, discomfort, gender, and grip strength. The 24 volunteer subjects (12 males, 12 females) performed five grips squeezing their hardest for 2 minutes at each of the five grip spans on the Jamar grip dynamometer. The grip strength was recorded using the UPC software and then averaged for each of the 30 second intervals. The data was analyzed using ANOVA, post-hoc (Tukey) hypothesis tests, and regression. In the ANOVA analysis gender, grip span, time, and the interactions of gender-grip span, grip span-time, and time-gender were determined to be the significant effects. In all four of the 30 second intervals, average grip strength was significantly higher for males than females. Female average grip strength was found to be 70% of male average grip strength. The post-hoc (Tukey) tests showed that grip spans 3, 4, and 2 were significantly higher than grip spans 5 and 1. The anthropometry of several segments of the hand were found to be important predictors of grip strength and discomfort in the stepwise regressions. Grip span 4 had the highest average severity of discomfort, while grip span 1 had the most areas of the hand experiencing discomfort.
Validation of a Frequency Weighted Filter for Repetitive Wrist Flexion Tasks against a Load
Authors: Lin Mei-Li , Radwin Robert G.
Published: January 2012

This experiment validates an instrument that implements a force and frequency weighted filter for biomechanical stress exposure assessment. This filter network was developed based on a previously established discomfort model that associated physical stress of force, posture and repetition with subjective discomfort. A simulated industrial task was used in the current study to test the instrument involving repetitively transferring a peg and inserting it into a hole against a controlled resistance. Ten subject performed the task for six conditions. Continuous wrist angular data were recorded using an electrogoniometer and processed through the filter. Subjective discomfort was reported after performing the task for one hour using a 10 cm visual analog scale. The discomfort model was shown to estimate relative discomfort for the experimental conditions tested ( r2 = 0.98, p < .05). Linear regression analysis showed that the instrument aptly predicted subjective discomfort ( r2 = 0.87, p < .05). Applications and limitations of this instrument are explored.
Three-Dimensional Functional Capacity of Normals and Low Back Pain Patients
Authors: Ferguson Sue A. , Marras William S. , Crowell Robert R.
Published: January 2012

Most current functional capacity evaluations focus on sagittal range of motion, strength testing as well as simulation of daily activities and job tasks as measures of wellness. The goal of this study was to evaluate the dynamic functional motion capacity of normals and low back pain patients in the three cardinal planes of the body. The hypothesis was that injury would not only affect sagittal motion but also lateral and twisting motions that would load the spine in a different manner. Trunk motion parameters of range of motion (ROM), velocity and acceleration were measured in all three planes of the body as subjects performed three separate experimental tasks, eliciting motion in each plane of the body. The MANOVA results showed a significant difference between the patients and normals. The final discriminant function model predicting membership for the two groups contained ROM, velocity, and acceleration parameters with two measures from each experimental task. The cross-validation error rate for the model was 4%. These results provide insight into new methods for functional capacity evaluation of low back pain patients which may influence return to work decisions.
Simulator Limitations and Their Effects on Decision-Making
Authors: Mackenzie Colin F. , Harper Ben D. , Xiao Yan
Published: January 2012

The use of simulators for skill evaluation is common in a number of fields, but the effect that various characteristics of simulators have on subject performance is not fully understood. Ten experienced trauma anesthesiologist participated in a full mission simulation of a real video taped trauma case management. This case contained critical events that require the participants to use clinical examinations and familiar and unfamiliar equipment contained in the simulator. Participants' performance differed from both the performance in the real case and ideal performance. The unfamiliarity with one complex piece of the equipment (ventilator function and controls) caused 4 out of 10 participants to be unable to finish the simulation. Surprisingly, unfamiliarity with another piece of equipment (new to all participants) did not have any dramatic impact. Anesthesia simulators have been successfully used in training anesthesiologists, but the demands of evaluation of clinical skills differ from training. Complex equipment and the limitation in realism of the mannequins in the anesthesia simulators prevent fair assessment of clinical diagnostic skills.
Subject Differences in the Perception of Risk
Authors: Young Stephen L.
Published: January 2012

Previous studies dealing with perceived risk have made the implicit assumption that all subjects view the product in roughly the same way. Since the risk literature suggests that different person-types exist (e.g., risk-takers, risk-avoiders, etc.), it seems as if subject characteristics would affect the way that people perceive products and their risks. The goal of the present study is to examine subject differences in perceived risk by (1) parsing subject into meaningful groups, and (2) examining the extent to which these groups access different information about products when evaluating the risks. Using cluster analysis, subjects were assigned to one of three groups. These groups differed from one another in terms of how they viewed the products as a whole. Group 1 perceived all products, in general, to be hazardous—they were labeled Fearful. Group 2 perceived the product as non-hazardous, while having a very low degree of personal knowledge of the risks or familiarity with the products—they were labeled Fearless. Group 3 perceived the products, as a whole, to be non-hazardous, but they had a high degree of personal knowledge of the risks and familiarity with the products—they were labeled Informed. These three groupings of subjects differed in the types of information they accessed when evaluating the products. Group 1 (Fearful) attended to information about the hazards, making fine distinctions between levels of hazardousness for different products. Group 2 (Fearless) and Group 3 (Informed) did not make such distinctions with regard to hazardousness. Rather, they perceived most products to be about the same, unless there was the potential for catastrophic consequences. In general, this study demonstrated that people could be assigned to meaningful and homogeneous groups, whose perception of products (and product risks) was determined, to some extent, by person-traits.
Framing Effect in Decision Making in Wildland Fire Safety Officers
Authors: Glusker Stephanie A. , Chadwick Nicki Jo , Braun Curt C.
Published: January 2012

Two studies were conducted to investigate factors influencing decision making in fire safety officers. In Experiment 1, 59 fire safety officers and trainees, and 24 undergraduate students read decision scenarios. For each scenario, participants were required to chose one of two possible outcomes, a sure thing or a gamble. All scenarios were framed both positively, in terms of gains, and negatively, in terms of losses. It was hypothesized that safety officers and trainees would be more risk aversive in their decision making than other populations. It was also hypothesized that participants would be risk aversive in the positive frame and risk seeking in the negative frame. The results showed no significant difference between groups. However, there was a significant main effect for frame. Further analysis revealed a significant Frame x Scenario interaction. Varying resources and probabilities in the scenarios made conclusions regarding this interaction impossible. Experiment 2 was conducted to determine if resource, probability, probability of gain, and value influence risk seeking/aversion. 114 fire safety officers responded to scenarios as in Experiment 1. Scenarios and possible outcomes were created using a factorial combination of resource, probability, probability of gain, value, and frame. Probability and probability of gain served as between subjects variables. It was hypothesized that there would be differences in risk seeking/aversion within resource, probability of gain, value, and frame. The results showed a statistically significant effect for resource, probability, probability of gain and value. All main effects were qualified by significant interactions which are discussed. The findings indicate that for fire safety officers the framing effect is a function resource, probability, probability of gain and value.
GINA: A Workbench for Constructing Interface Agents
Authors: Zachary Wayne W. , Le Mentec Jean-Christophe , Schremmer Serge
Published: January 2012

The Generator of INterface Agents (GINA) is a software workbench that supports the development of interface agents. Viewing agent development as a cognitive engineering process, GINA supports development of agents from cognitive models of the human whose functions are being automated and/or supported by the agent. Built around the COGNET cognitive task analysis language, GINA provides software tools to support building and editing cognitive models, translating the models into executable forms that provide the reasoning kernel of an intelligent agent, building a software shell that allows this kernel to communicate with the targeted application environment, and testing and debugging the resulting agent.
Implementing the ANSI Z-365 Standard for Control of Work-Related Cumulative Trauma Disorders
Authors: Armstrong Thomas J. , Snook Stover H. , Fine Larry J. , Hales Thomas R. , Radwin Robert G.
Published: January 2012

This panel will present an overview of the latest working draft of the ANSI Z-365 standard for control of work-related cumulative trauma disorders and discuss how both newly established and already successful ergonomics programs in large and small companies can utilize the consensus standard. The audience will have an opportunity to make inquiries to the ANSI standard committee chairs, discuss relevant technical aspects of the standard, exchange views about the proposed standard, and offer perspectives on the implementation of ergonomics programs in industry.
Field Measurement of Naturalistic Backing Behavior
Authors: Harpster Jeff , Huey Richard , Lerner Neil
Published: January 2012

A series of observations and measurements were made as subjects drove their own vehicles in an assortment of naturalistic backing tasks conducted on public roads in real world driving conditions. As the subjects performed eight backing tasks, the following data were collected: glance direction, hand position, velocity and acceleration, and distance to object in back of the vehicle. The results provide a set of normative data usable by automotive system designers for the design of backing warning systems and other ITS applications. The results of this study were divided into glance direction, backing speed, and time-to-collision. Glance directions were found to vary greatly between tasks. Elderly drivers demonstrated more use of their mirrors and looked over their shoulder less then the young drivers. Looking over the right shoulder was the most frequent glance location across all tasks. Except for the extended backing maneuvers, backing speeds averaged around 4.8 km/h (3 mph). The maximum backing speed for the young drivers was faster than the elderly and males backed faster than females. The time-to-collision was relatively constant over the majority of the backing sequences. Minimum time-to-collision values were generally over 2 seconds.
Initial Driver Avoidance Behavior and Reaction Time to an Unalerted Intersection Incursion
Authors: Hankey Jonathan M. , McGehee Daniel V. , Dingus Thomas A. , Mazzae Elizabeth N. , Garrott W. Riley
Published: January 2012

Initial driver avoidance behavior and reaction time to an unexpected intersection incursion was determined using a state-of-the-art motion-based driving simulator (Iowa Driving Simulator). The intersection used for the experiment was on a two-lane rural highway (55 mph speed limit) that controlled perpendicular (crossing) traffic by stop signs. The subject vehicle did not have to stop and had the right-of-way on the highway. At one of three possible start times, an intersecting vehicle began moving into the intersection in front of the subject vehicle. This incurring vehicle intersected from either the driver's left or right side. Ninety-six subjects participated in the study. Subjects in the shortest, most severe collision avoidance situation were significantly slower to react and equally likely to steer or release the accelerator pedal as the initial avoidance maneuver. Subjects in the longest, least severe collision avoidance situation often released the accelerator pedal and braked prior to steering. Gender differences are also discussed.
Age Differences in Visual Abilities in Nighttime Driving Field Conditions
Authors: Chrysler Susan T. , Danielson Suzanne M. , Kirby Virginia M.
Published: January 2012

This study was conducted to provide field data on age differences in sign legibility and object detection. Two age groups of healthy drivers with normal vision were tested for nighttime visual ability. The older group had an average age of 65.6 years and the younger group averaged 22.5 years. The field study was conducted on a private road with the subjects seated in the front passenger seat. Subjects performed a Landolt ring legibility task for four types of signs; positive and negative contrast, new and worn material. Subjects also performed object detection tasks using a small object and a pedestrian target appearing in average and low reflectance. In addition, sign legibility and object detection were completed for some trials using a simulated inclement weather visor to create a worst-case scenario. The object detection task was also completed in the presence of glare from oncoming headlamps. Results showed that older driver's legibility distances were 65% those of the younger drivers. Age differences in the object detection task ranged from a 20% to a 45% reduction for older drivers across visibility conditions.
Older Commercial Drivers: Literature Review
Authors: Brock John F. , Llaneras Robert E. , Swezey Robert W.
Published: January 2012

This paper reports on a comprehensive literature review of the older driver and older commercial driver literature. The review included sources of data from private and government data bases, empirical research published in public journals, and existing commercial vehicle driving task analyses. The review uncovered key abilities which degrade with age, including: static visual acuity, dynamic visual acuity, contrast sensitivity, useful field of vision, field dependence, depth perception, glare sensitivity, night vision, audition, reaction time, multilimb coordination, control precision, decision-making, selective attention, and attention sharing. The review also sought to identify which of those abilities might effect the performance of critical commercial driving tasks. Although much investigation has been done of older person abilities, most of the studies have looked at persons in either medical or judicial systems. We found little data on driving degradation of older but healthy drivers.
A Driving Simulator Study of the Performance Effects of Low Blood Alcohol Concentration
Authors: Allen R. Wade , Parseghian Zareh , Stein Anthony C.
Published: January 2012

There is a large body of research that documents the impairing effect of alcohol on driving behavior and performance. Some of the most significant alcohol influence seems to occur in divided attention situations when the driver must simultaneously attend to several aspects of the driving task. This paper describes a driving simulator study of the effect of a low alcohol dose, .055 BAC (blood alcohol concentration %/wt), on divided attention performance. The simulation was mechanized on a PC and presented visual and auditory feedback in a truck cab surround. Subjects were required to control speed and steering on a rural two lane road while attending to a peripheral secondary task. The subject population was composed of 33 heavy equipment operators who were tested during both placebo and drinking sessions. Multivariate Analysis of Variance showed a significant and practical alcohol effect on a range of variables in the divided attention driving task.
Analysis of Interview and Focus Group Data for Characterizing Environments
Authors: Cohen Sally M. , Gravelle Michael D. , Wilson Karen S. , Bisantz Ann M.
Published: January 2012

This paper describes a novel use of interview and focus group data to generate and substantiate hypotheses about a complex environment. In addition, it shows how MacSHAPA, a tool developed for analyzing sequential data, is a useful tool for analyzing these data. Although interviews and focus groups have been used extensively in social science and marketing, there are few examples documenting the use of these techniques in user-centered design. Furthermore, MacSHAPA has not been used to perform content analysis on interview and focus group data. In this paper, interviews and focus groups were collected as part of a larger study to understand human factors issues in quick service restaurant chains. These data were analyzed using MacSHAPA to perform content analysis. The results generated hypotheses that were validated by other data collection activities, and substantiated hypotheses that were derived by other analyses. The shortcomings and tradeoffs of using this analysis method for a human factors investigation are discussed.
Advanced Taxi Map Display Design for Low-Visibility Operations
Authors: Battiste Vernol , Downs Michael , McCann Robert S.
Published: January 2012

Conducting gate to gate operations during reduced visibility conditions is a major impediment to scheduled and unscheduled flight operations in the National Airspace System (NAS). Takeoff and landing minima are predicated on aircraft equipage and airport visibility (e.g., at some major airports, operations are terminated when visibility is below 700 ft runway visual range (RVR). Although some aircraft can land with zero-zero visibility, there are no ground or flight deck systems that allow them to taxi under low visibility conditions. A map display system designed to support low visibility taxi was evaluated by 12 B-747 flight crews in NASA's Crew Vehicle System Research Facility (CVSRF). Three taxi-map conditions were compared: paper map only, basic moving map, and advanced moving map. Crews landed and taxied along 24 different taxi routes under three visibility conditions: unlimited visibility, 700 ft RVR, and 300 ft RVR. Taxi time, errors and workload were collected for each taxi operation. Video tape recordings captured crew interactions and head-up and head-down times. Taxi times and errors were significantly better for crews with electronic maps than for crews with a paper map. Although crews with the advanced map experienced significantly more head-down time, the head down interval was significantly less than with the paper map and crew workload was significantly less. During the post-flight design review, pilots identified improvements in procedures and formatting that might enhance performance. They developed a procedure for safely switching from the NAV display to the map; and in general their comments were very favorable.
Switching attention between tasks: Exploration of the components of executive control and their development with training
Authors: Gopher Daniel , Greenshpan Yaakov , Armony Lilach
Published: January 2012

Top down processes guided by attention and intention, have been recognized to be important determinants, and necessary complements in the formulation and guidance of skilled performance. The present paper summarizes the results of four experiments conducted to investigate the control operations and the cost involved in switching attention between task dimensions and attention strategies. Subjects were asked to switch between judging the value of digits, or the number of digit elements, in rows of digits presented on the screen. Alternatively they performed the task, switching between speed or accuracy emphasis. The experimental results provide strong evidence for the work of executive processes which operate as attention strategies and policy regulators. They are executed top down, in the service of intentions and basic attention policies, but depend on the existence of task representations, including the “so called” automatic performance units. Executive processes are shown to have sizable operation costs, over and beyond those imposed by the direct processing and response demands of the performed tasks. These costs are reduced with specific training focusing on the improvement of control functions.
Training Interface Design and Task Analytic Methods
Authors: Crosland Marcia B. , Walker Neff , Corso Gregory M. , Sparre Erik
Published: January 2012

Analytic techniques are needed that will guide the design of system interfaces to evoke effective control strategies. This study compared the strategic patterns of system control exhibited by operators during training with three interface designs. Twenty-eight right handed undergraduate students were trained to control a simulated evaporator over a four day period. Reaction time, number of control actions, the amount of equipment damage and system deviation in operating pressure, separator level, and product composition were collected and analyzed. The results show reliable differences between operator control strategies using the interface designs associated with operating pressure, product composition, and separator level.
Developing Automated Methods to Quantify the Visual Stimulus for Cybersickness
Authors: Kennedy Robert S. , Berbaum Kevin S. , Dunlap William P. , Hettinger Lawrence J.
Published: January 2012

Simulator sickness is a significant human factors issue in simulator and virtual environment systems. The extent to which users are adversely affected by sickness-inducing stimuli in virtual environments may hinder the behavioral goals sought (training, systems evaluation, etc.). To alleviate the problem, it is first necessary to accurately and reliably quantify the amount and type of visual motion stimulation that leads to motion sickness-like discomfort. This paper describes a human performance-based approach to the development of a system capable of measuring the visual stimulus for motion sickness. Military flight simulator trainees reported severity levels of sickness. A video camera was used to capture a significant portion of the simulated out-the-window visual stimuli to which they were exposed and a PC-mounted, frame-grabber algorithm was used to score the kinematic characteristics of that stimulation. Results show a significant positive correlation between roll motion and overall sickness. Development of these and other methods to quantify the visual stimulus for cybersickness are discussed.
Stereoscopic Depth Perception in Simulated Displays: What Helps and What Hurts?
Authors: Akers John W. , Davis Elizabeth T. , King Robert A.
Published: January 2012

We tested the effect of direction of retinal disparity and stimulus orientation on stereoscopic depth perception to answer three questions. First, are some directions of disparity more efficient than others in providing stereoscopic depth information? Second, does the orientation of an object affect perceived stereoscopic depth? Third, are there any interactions between these parameters? Subjects were tested using a psychophysical, method of constant stimuli procedure with a modified Wheatstone stereoscopic display. Disparity threshold measurements show a significant effect of direction of retinal disparity. Contrary to expectations however, no significant effect of orientation was found if vertical retinal disparities were excluded from the analyses. Stereoacuity thresholds were measurable with obliquely-oriented stimuli and vertical disparity, however, suggesting that vertical disparities can provide useful information. The implications of these results for the graphics, calibration, and design of stereoscopic displays (e.g., HMDs) are discussed.
The Effects of Spatial Auditory Preview on Dynamic Visual Search Performance
Authors: Elias Bartholomew
Published: January 2012

Since the auditory system is not spatially restricted like the visual system, spatial auditory cues can provide information regarding object position, velocity, and trajectory beyond the field of view. A laboratory experiment was conducted to demonstrate that visual displays can be augmented with dynamic spatial auditory cues that provide information regarding the motion characteristics of unseen objects. In this study, dynamic spatial auditory cues presented through headphones conveyed preview information regarding target position, velocity, and trajectory beyond the field of view in a dynamic visual search task in which subjects acquired and identified moving visual targets that traversed a display cluttered with varying numbers of moving distractors. The provision of spatial auditory preview significantly reduced response times to acquire and identify the visual targets and significantly reduced error rates, especially in cases when the visual display load was high. These findings demonstrate that providing dynamic spatial auditory preview cues is a viable mechanism for augmenting visual search performance in dynamic task environments.
Evaluation of Ansi/Hfs 100-1988 Flicker Assessment Method
Authors: Jones Megan M. , Beaton Robert J.
Published: January 2012

This work examined the method used in the American National Standard for Human Factors Engineering of Visual Display Terminal Workstations (ANSI/HFS 100–1988) to evaluate flicker from Cathode Ray Tube (CRT) displays. The standard specifies that “the display must be found to be flicker free for at least 90 percent of a sample of the user population under conditions representative of actual use.” However, the associated flicker compliance test is questioned as not representing realistic office viewing conditions.

A psychophysical experiment was conducted to compare the detection of CRT flicker, in terms of Critical Flicker Frequencies (CFFs), under the ANSI/HFS 100–1988 viewing conditions (i.e., 0 and 20 degrees viewing angle, dark ambient, and hyphen-filled, bright-on-dark character screen) with several others, defined by combinations of ambient illuminance, display luminance, display viewing angle, and screen pattern. As expected, the results indicate that these four factors significantly affect CFFs. More importantly, the CFFs obtained under these viewing conditions were higher than those obtained under the ANSI/HFS 100–1988 viewing condition.

The findings of this work indicate that the ANSI/HFS 100–1988 flicker assessment method is too conservative and may not be sufficient to ensure flicker-free viewing of CRT displays under typical office viewing conditions.
Performance Benefits with Scene-Linked Hud Symbology: An Attentional Phenomenon?
Authors: Levy Jonathan L. , Foyle David C. , McCann Robert S.
Published: January 2012

Previous research has shown that in a simulated flight task, navigating a path defined by ground markers while maintaining a target altitude is more accurate when an altitude indicator appears in a virtual “scene-linked” format (projected symbology moving as if it were part of the out-the-window environment) compared to the fixed-location, superimposed format found on present-day HUDs (Foyle, McCann & Shelden, 1995). One explanation of the scene-linked performance advantage is that attention can be divided between scene-linked symbology and the outside world more efficiently than between standard (fixed-position) HUD symbology and the outside world. The present study tested two alternative explanations by manipulating the location of the scene-linked HUD symbology relative to the ground path markers. Scene-linked symbology yielded better ground path-following performance than standard fixed-location superimposed symbology regardless of whether the scene-linked symbology appeared directly along the ground path or at various distances off the path. The results support the explanation that the performance benefits found with scene-linked symbology are attentional.
Displaying Uncertainty in Advanced Navigation Systems
Authors: Andre Anthony D. , Cutler Henry A.
Published: January 2012

Few human factors studies have addressed the issue of displaying the uncertainty of information provided to users; an issue of growing importance given the current proliferation of advanced situation awareness and navigation displays used in the aviation, automotive and maritime environments. This paper first discusses the growing need to develop guidelines concerning when and how to display uncertainty, and then describes the results of two initial studies aimed at both demonstrating the general utility of displaying uncertainty, and determining the optimal ways to visually represent various levels of uncertainty. We conclude that the impact and effectiveness of future multi-sensor situation awareness displays will be dependent on the skillful presentation of data uncertainty.
Being Certain About Uncertainty: How the Representation of System Reliability Affects Pilot Decision Making
Authors: Banbury Simon , Selcon Stephen , Endsley Mica , Gorton Tessa , Tatlock Kerry
Published: January 2012

The present study investigated how pilot decision making is affected by the manner in which the decision support information regarding system reliability is presented, by requiring aircrew participants to respond to a machine-identified target with a “shoot/no shoot” decision. The study investigated whether the provision of an alternate option to the primary identification would affect the decision to shoot, especially if this secondary option was either another enemy aircraft or a friendly fighter. In addition, two different representations were evaluated; one in which the information was presented as system uncertainty; and the other in which it was presented as system confidence. The results indicated that decision making behaviour changed when the system explicitly identified a friendly aircraft as the secondary target — prior willingness to fire on a target with a relatively high level of uncertainty disappeared. The time taken to make the decision was also found to be mediated by what information was given. These results are interpreted in the light of current trends in decision support development and design guidelines are discussed.
Developing Data Link User-Interface Designs Using Pilot Conceptual Networks
Authors: Williams Kevin W. , Joseph Kurt M.
Published: January 2012

One hundred and forty-eight pilots were asked to categorize a list of flight-related data elements that could be sent via data link from an FAA automated flight service station to an aircraft or vice versa. The categorization was used to construct a matrix of proximity values for each of the data-element pairs so that a conceptual network of the elements could be constructed using the Pathfinder algorithm developed by Schvaneveldt, Durso, and Dearholt (1985). Additionally, pilots were asked to judge each data element according to how useful the element was for the functions of communication, navigation, and surveillance within the general aviation (GA) flight environment. Elements scoring high on each of these flight-related functions were then subjected to a Pathfinder analysis. The conceptual networks that were created as a result of these analyses are discussed in relation to the development of data link user interfaces for the GA cockpit.
A Comparative Analysis of Sagat and Sart for Evaluations of Situation Awareness
Authors: Endsley Mica R. , Selcon Stephen J. , Hardiman Thomas D. , Croft Darryl G.
Published: January 2012

Situation awareness (SA) has become an important criterion for systems evaluation efforts. Several measures of SA have been developed, the most widely used among them being the Situation Awareness Global Assessment Technique (SAGAT) and the Situational Awareness Rating Technique (SART). SAGAT provides an objective measure of SA based on queries during freezes in a simulation. SART provides a subjective rating of SA by operators. This paper presents a direct comparison of the two measures which were used within a display evaluation study. It was found that both SART and SAGAT contributed sensitivity and diagnosticity regarding the effects of the display concept. The SART measure was highly correlated with subjective measures of confidence level, a simple subjective SA measure and a subjective performance measure. The SAGAT and SART measures were not correlated with each other. The implications of these findings for the interpretation of subjective SA measures are discussed as well as advantages and disadvantages of both measurement approaches.
Human Factors in Light General Aviation Aircraft: A Failure for our Profession?
Authors: Wise John A. , Abbott David W. , Beringer Dennis B. , Koonce Jefferson M. , Kite Kirsten , Stokes Alan F.
Published: January 2012

Aviation can be described as the birth place of human factors. A quick glance at the funding sources and the publications in the discipline shows that we are still quite tightly tied to aviation. Cockpit automation, mode errors, ATC workload are among topics that are currently well represented in the human factors literature. However, the place where human factors could make it biggest impact in terms of safety and error prevention, general aviation (GA), is still basically a human factors waste land. If one looks at the current statistics of light aircraft accidents, it reads like a list of errors and design problems described in any introductory human factors text.
A Direct Perception Display for Rule-Based Behavior: Supporting Power Plant Startup with a “Lattice” Display
Authors: Reising Dal Vernon C. , Sanderson Penelope M. , Jones Barclay G. , Moray Neville , Rasmussen Jens
Published: January 2012

Research over the last decade on interface design has suggested that “configural” or “direct perception” displays provide better support for complex operator tasks than single-sensor single-indicator displays. In this paper we focus on the development of displays to support the human operator role in nuclear power plant start-up procedures, which involve rule-based behavior. During start-up operators construct a functioning plant. This process can be characterized as climbing an “abstraction/aggregation hierarchy” from initiating low-level physical functions, combining them into generalized and abstract functions until the plant fulfills its functional purpose (Rasmussen, Pejtersen, & Goodstein, 1994). We introduce a graphical interface based on a visual lattice representation of the abstraction/aggregation hierarchy for nuclear power plant startup which (1) provides constant feedback through the lattice display about the level of abstraction/aggregation achieved, (2) provides feedback about system state through direct perception displays, and (3) promotes the correct sequence of actions.
Modeling the Effects of Sleep Deprivation on Real-Time Risky Decision-Making
Authors: Hurwitz Joshua B.
Published: January 2012

Increased real-time risk-taking under sleep loss could be marked by changes in risk perception or acceptance. Risk-perception processes are those involved in estimating real-time parameters such as the speeds and distances of hazardous objects. Risk-acceptance processes relate to response choices given risk estimates. Risk-taking under fatigue was studied using a simulated intersection-crossing driving task in which subjects decided when it was safe to cross an intersection as an oncoming car approached from the cross street. The subjects performed this task at 3-hour intervals over a 36-hour period without sleep. Results were modeled using a model of real-time risky decision making that has perceptual components that process speed, time and distance information, and a decisional component for accepting risk. Results showed that varying a parameter for the decisional component across sessions best accounted for variations in performance relating to time of day.
The Application of the Ecological Interface Design Approach to Neonatal Intensive Care Medicine
Authors: Sharp Thomas D. , Helmicki Arthur J.
Published: January 2012

Ecological interface design techniques were used to first model and then develop an interface to help clinicians assess tissue oxygenation in a neonatal intensive care unit. Several challenges were encountered during this work. The abstraction hierarchy model structure that was used has limitations in this environment. The first limitation concerned the depth of knowledge that was available. Tissue oxygenation is a complex, and not totally understood process. Furthermore, it is truly distributed in nature. Both these limit the level of detail that could be included in the system model. Second, in this environment the sensor suite is very limited and is defined a-priori. Therefore, many of the variables that were identified as important in the abstraction hierarchy model are impossible to measure. Despite these limitations, the interface that resulted from the abstraction hierarchy model compared favorably to the existing interface in a simulated clinical environment.
Advancing Performance Measurement in Cognitive Engineering: The Abstraction Hierarchy as a Framework for Dynamical Systems Analysis
Authors: Yu Xinyao , Lau Elfreda , Vicente Kim J. , Carter Michael W.
Published: January 2012

This paper describes a novel approach to performance measurement that is based on the abstraction hierarchy (AH) and dynamical systems theory (DST). Each level in the AH provides a systematic way of identifying a state space that can be used to conduct complementary DST analyses. This approach was applied to data from a longitudinal experiment that measured subjects' performance in interacting with a process control microworld simulation on a quasi-daily basis over a period of six months. The variability in trajectories at each level of the AH was examined over successive blocks of trials. The analyses at different levels revealed complementary insights into subjects' behavior. Collectively, the results provided objective, quantitative evidence that highly experienced and very proficient subjects were actually performing the task using very different strategies. Thus, integration of the AH and DST provides a novel measurement approach that can reveal unique and important insights into performance.
Designing Displays Under Ecological Interface Design: Towards Operationalizing Semantic Mapping
Authors: Reising Dal Vernon C. , Sanderson Penelope M.
Published: January 2012

In recent years, there has been growing interest in Ecological Interface Design (EID), which is the end product of cognitive work analysis (CWA). Even though the process of CWA has been thoroughly explained in Rasmussen, Pejtersen, and Goodstein (1994), there are few detailed examples on how one performs the individual steps involved. This paper deals specifically with the final semantic mapping stage. To date, moving from the system equations given by the work domain to particular display geometries has required some open-ended artistry. We provide several examples of how semantic mapping can be systematically achieved, either by i) borrowing from well-established theoretical depictions of a phenomenon, ii) adapting preexisting displays to fit a particular need, or iii) inventing visual forms by finding a spatial representation for the underlying state equations.
Measuring the Usability of Web Sites
Authors: Kirakowski Jurek , Cierlik Bozena
Published: January 2012

User-based satisfaction questionnaires have so far been little used in the evaluation of web sites. A 60-item questionnaire was developed following a factor model used with success for conventional software evaluation. This questionnaire was shown to have high reliabilities and a large database of expected values was gathered for it. It was employed in a study evaluating chamber of commerce web sites in two European cities, together with metrics which measured aspects of user performance and heuristic analysis. It was shown that the questionnaire results agreed with and amplified the other data. The results indicate that questionnaire data can be both reliable and valid for the assessment of user satisfaction with web sites. Some future directions for research are discussed.
The Human Factors Issues in Information Security: What are They and Do They Matter?
Authors: McCauley-Bell Pamela R. , Crumpton Lesia L.
Published: January 2012

The information technology field has been increasingly plagued by threats to the security of information systems, networks, and communication media. The solutions to these problems have primarily focused on the techniques to more closely safeguard networks (i.e. firewalls) with similar efforts being put into assessing the vulnerabilities of the hardware and software aspects of the systems. With the exception of discussions into more creative password selection, discussion pertaining to the role of the user, can play in reducing the risk of human error and thus promoting system security has been extremely limited. This lecture will present an overview of information security issues impacted by human interaction that may or may not play a role in promoting system security. Understanding that information systems are in fact composed of hardware and software components which must be addressed using traditional information security protocol, this lecture will provide an understanding of the possible risk that the human/user poses to an information system. Once the risks or factors associated with the human in the security of the system are identified, the next question is do the factors matter? The objective of this lecture is to present an intellectual discussion of human factors issues and their impact on information security. This is an important discussion topic that the information technology field can not afford to ignore.