bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Guidelines for Designing User Interface Software
Authors: Normore Lorraine F. , Tijerina Louis
Published: January 2012

Sixteen systems analysts and programmers were asked to rate and rank computer system interface guideline topics derived from Smith and Aucella's, 1983, “Design Guidelines for User-System Interface Software”. The participants generally agreed that guidelines on these topics are desirable. However, both ratings and ranking data showed that the participants did differentiate among the topics. The topic “user guidance” which included guidelines on informative messages and ‘help’ systems was the most consistently highly rated/ranked topic. In addition, the perceived need for guidelines on sequence control, data display, and data entry was high.
Designing User Interfaces: A Classroom Experience in Iterative Software Design
Authors: Hoffman Susan C.
Published: January 2012

A program was developed to expose undergraduate Computer Technology students to methods for designing and evaluating user dialogue in interactive software. The class was given an assignment to develop an Interactive program for use by the general public. This was given prior to any experience using concepts in Human Factors, a Standard Development Process, or general guidelines for evaluating the user interface. Task analysis was performed extracting data from video tapes. Formal lecture material on designing user interfaces incorporating good Human Factors was then introduced. Students then were given the opportunity to modify their programs and assess the value of these changes through retesting. Substantial improvements in both transaction performance times and accuracy occurred during the evaluation of the revised applications. This program was an effective method for demonstrating the complexities involved in designing and implementing interactive software.
Cabin Noise Levels in Single Engine General Aviation Aircraft
Authors: Hughes Stanley T. , Koonce Jefferson
Published: January 2012

Sound level measurements were made on several of the most popular general aviation aircraft produced. Measurements were taken at various flight milestones such as; run up, taxi, climb, cruise power and descent. For each of the aircraft a time weighted mission sound level was obtained, using three different mission scenarios, varying only in flight time. For each of the three scenarios, and for all aircraft, the time weighted noise values obtained were an or exceeded the 85 dBA limit recommended by NIOSH. The results of this study indicate that a substantial percentage of general aviation pilots will show some loss of hearing due to the high noise levels present in their cabins. Recommendations are made for protection of occupants of general aviation aircraft.
Isoperformance: A Methodology for Human Factors Engineering Design
Authors: Jones Marshall B. , Kennedy Robert S. , Turnage Janet J.
Published: January 2012

The literature of applied psychology rarely, if ever, allows an unambiguous answer to a particular problem. Almost always there is a hiatus between what is known and what one wants to know. If the tasks are the same, personnel, performance measures, temporal relations or environmental conditions are different. Oftentimes nothing is quite the same as what has been studied in the literature. Inevitably, these gaps are closed by “expert judgment.” People who are experienced in the field extrapolate from what has been studied to the real-world case in hand. This inevitability is not, however, the end of the matter. Expert judgment can be utilized in many different ways and some ways are better than others. The principal issues are: precisely what are the experts to be asked, how is their consensus to be determined, and how is that consensus to be used relative to the real-world problem in hand. This discussion will describe one way of answering these questions. It is called “isoperformance.” The key feature of this approach is the design of an “ideal experiment.” This experiment then functions as a framework for both what is known in the literature and expert judgment.
Standardization in Anthropometry and Biomechanics
Authors: Kroemer Karl H. E.
Published: January 2012

Describing body size (anthropometry) and physical properties of the body (biomechanics) are areas of interest both in research and in application. The human factors engineer needs anthropometric and biomechanical information primarily for designing the operator/equipment interface. Available information is piecemeal, incomplete, and often not compatible since researched and provided in various scientific disciplines. However, even the researcher is hindered by the “scatter” of data, measuring techniques, and research objectives. Hence, an effort to standardize in the areas of anthropometry and biomechanics would, if done properly, help both scientists and engineers.
Analysis of Hand Tool Use in the Underground Mining Industry
Authors: Lavender S. A. , Marras W. S. , Lundquist R. G. , Rockwell T. H.
Published: January 2012

A research project that is sponsored by the Bureau of Mines, Department of Interior and conducted by Ohio State University is analyzing the accidents caused by hand tools used in the underground coal, metal, and nonmetal mining industries. To describe the accident types and the resulting injuries, a thorough search was conducted of a computer data base of mining-related accidents. After sorting for data pertaining to hand tools, analyses were carried out to determine likely scenarios, and their probability of occurrence, for the various hand tool injuries. This project, which summarized accident data for a six-year period, is the first comprehensive evaluation of hand tool accident data related to underground mining. The method of accident classification, which is based on accident type, part of body injured, and nature of the injury, allows assessment of the key components of the hand tool injury. Furthermore, this analysis, in conjunction with the scenario development, provides direction for future research into hand tool ergonomics.
Safety Related Applications of Simple Optical-Electronic Sensors for Robots
Authors: Briggs Raymond P. , Rahimi Mansour
Published: January 2012

Many devices have been developed to promote the safety of people working with robots. The most promising appear to be on board passive sensors that involve optical-electronic vision sensors. An approach to evaluation of the adequacy of simple sensors is suggested.
Learning-by-Doing versus Fully-Informing as Training Strategies
Authors: Martin David W.
Published: January 2012

A learning-by-doing training technique was compared to full-information training in both a generic laboratory task and an application setting. The generic task required trainees to search for targets in a dynamic numerical array. Cells in the array were defined by rate of change, probability of target, and cost of errors. Learning-by-doing trainees had to adopt attention allocation strategies using only running point-total feedback. Informed subjects were given cell parameter values. During training informed subjects were superior until the sixth training day. At transfer to a new, unknown parameter set learning-by-doing subjects showed a clear superiority until the third day of transfer. They had apparently learned to infer system dynamics from system feedback. This finding was not replicated in the context of a flight simulator. The failure to validate the laboratory result in the more applied setting could be due to the effects of additional dimensions and skills required for the flying task that are not included in the laboratory task.
Remedial Computer-Based Testing and Training for M1 Tank Commanders
Authors: Elder B. Leon , Harris Carolyn D. , Knerr C. Mazie
Published: January 2012

The Training Technology Field Activity (TTFA) at Ft. Knox applies recent developments in technology to meet the training needs of M1 tank commanders. The training includes computer-based instruction to provide remedial training in prerequisite skills. The instruction applies recent advancements in video technology using a state-of-the-art CBI authoring and delivery system. Self administered, microprocessor-based, videodisc supported, testing and instructional courseware was developed for a selected set of remedial tasks for a tank commander course. Training methods were tailored to the characteristics of the tasks using both traditional and innovative, cognitively-based, task-analytic methods. The training was developed and delivered using the MicroTICCIT system. The courseware is menu driven, is student friendly, and requires minimum student training time to use. The light pen is used for all student input. The courseware provides the diagnostic testing, the training for those who fail, and a retest. This paper discusses the tasks that are trained, the technological alternatives considered, and describes methods used to design and present the instruction.
Empirical User Modeling: Command Usage Analyses for Deriving Models of Users
Authors: Anderson Matthew P. , McDonald James E. , Schvaneveldt Roger W.
Published: January 2012

Models of users' procedural knowledge were derived from the records of command usage obtained from nine experienced users of the Unix operating system. Pairwise transitions between user command entries were analyzed for the purpose of identifying salient command patterns associated with task-based user behaviors. Structural models of command usage patterns were obtained from Pathfinder network scaling of Unix command events. The network representation of command patterns was evaluated as a method for abstracting users' procedural knowledge. These network scaling solutions revealed patterns that were common both within and across users' command usage.
The Human Side of Technology: A Panel
Authors: Price Harold E. Smoke
Published: January 2012

One of the most durable topics of discussion in the Human Factors Society is the question of technology and its impact on the field of human factors. There seems to be consensus on three points. First, the fundamental technologies that will affect human-machine system design for the rest of this century are pretty well known. While there may be continued improvements in such areas as microprocessors, flat panel displays, and interactive devices (including voice), there are no dramatic breakthroughs anticipated or needed. Second, we must learn to use the technology we now have and improve the integration of humans into systems. In other words, we must understand how to use what we have in a way which will result in human-machine symbiosis. And third, we must ensure that designs are driven by user needs and not by technological possibility. Left unconstrained, technology will force its way into every human-machine interface that affects the larger system, and we may end up being the victims rather than the beneficiaries of technology.

This panel will explore the early lessons that have been learned about the use (or misuse) of technology in the eighties and the impact on the human factor in system design. The panel members provide insight and lessons learned to support the notion that there is a Human Side of Technology.
Subjective Workload under Individual and Team Performance Conditions
Authors: Beith Barry H.
Published: January 2012

This study compares an individual's workload when working alone versus working with another person on a complex cognitive task. Twenty-four participants worked alone and in dyadic teams under varying conditions of team interaction and time stress. Measures of performance and individual ratings of self and team workload were recorded. Results address subjective workload under individual and team conditions. Further individual perceptions of personal workload and team workload are compared. These results have implications for the use of teams in operational systems.
A Study of the Mental Model of a Complex Dynamic System: The Effect of Display Aiding and Contextual System Training
Authors: Zhang Kan , Wickens Christopher D.
Published: January 2012

The acquisition of mental models and the effect of instructions and a display aid on the performance on a complex dynamic processing system were examined in this experiment. Thirty subjects monitored a dynamic bar graph display of six system variables and were tested under three different conditions: 1) subjects were given contextual instructions and a picture display-aid which provided a perceptual context in which to interpret the changing variables (group P/B). 2) Subjects were only provided non-context instructions and tested by a bar graph display (group B). 3) A transfer group was trained under the same condition as same as group P/B and tested with the bar graph display (group P/B - B). The data showed that the combination of the context instructions and the meaningful display aid improved subjects' performance significantly. The accuracy of diagnosis of the group P/B was the highest among the three groups. It was also seen that training with the context instructions themselves could improve the accuracy of diagnosis although the difference between the transfer group and group B was not significant statistically.
Visual Display Representation of Multidimensional Systems: The Effect of System Structure: And Display Integrality
Authors: Casey Elizabeth J.
Published: January 2012

This study sought to determine whether the type of display that is most beneficial for performing supervisory tasks would change depending on the relationships between system components. Eight subjects detected and diagnosed failures for systems whose variables were related either by correlation or by causality. One of four dynamic displays represented the three system components: a set of bar graphs, a triangle, a pentagon, or a schematic face. Subjects supervising the correlational system diagnosed the system by choosing which component had become less correlated with the others. Subjects diagnosed the causal system by determining which way the causal structure relating the components had changed. For both the correlational and causal systems, and for both detection and diagnosis there was a cost to using object displays or a face display rather than bar graphs.
Principles of Film Editing and Display System Design
Authors: Wise John A. , Debons Anthony
Published: January 2012

Contemporary display systems are notorious for their lack of flow across display pages. The capabilities to dynamically change the makeup and layout of a display that are resident in windowing and sensor fusion systems are beginning to present the display system designer with even more complex display transition problems. The motion picture industry, on the other hand, has for years successfully presented a series of dynamic visual displays, where changes from one scene (or display) to the next has been accomplished with no notice, or where the change has actually enhanced the information flow to the viewer. This paper discusses how some of the techniques and principles used in making editing decisions might be applied to the design of display systems.
Learning and Preference for Icon-Based Interface
Authors: Brems Douglas J. , Whitten William B.
Published: January 2012

Icons, or graphic symbols, have recently become widely available as a means of human-computer interaction. The range of applications and interface styles that benefit from the use of icons have, however, not been extensively studied. This paper presents a case study of an interface in which some aspects seemed favorable for the use of icons, while other aspects seemed unfavorable. In such situations, interface decisions should benefit from testing learning and preference for possible icons. In this study, icons were easily learned, but verbal representations and labeled icons were preferred over unlabeled icons. These results underscore the idea that icon-based interfaces are not always preferred. Both “learning” and “preference” should be considered before implementing an icon-based interface for any new application.
Alphabet Soup: Case and Order in Index Search
Authors: Faivre Irene A. , Krysiak Deborah A.
Published: January 2012

Through experience, adult readers have developed strong expectations about the meaning of visually distinct characters in text organization. Typically, when upper-case or bold face words are included in lists, they indicate topic headings. Through their experience with simple indexes, adult readers learn that it is efficient to use these distinctive entries to facilitate scanning. However, many computer manuals employ the convention of printing reserved words in uppercase. These words are then included in the index in alphabetical order, without regard to their possible interpretation as topic headings. We compared the accuracy of rapid index scanning under conditions where the two meanings of upper-case either were in conflict or were not in conflict. We found that subjects were less able to spot lower-case targets when they were listed preceding a similar upper-case entry than when the upper-case entry was eliminated. Recommendations for eliminating the conflict situation are discussed.
The Impact of Automation on Error Detection: Some Results from a Visual Discrimination Task
Authors: Fuld Robert B. , Liu Yili , Wickens Christopher D.
Published: January 2012

A dynamic decision-making task was designed for microcomputer that allowed subjects to operate in either a manual mode, or an automatic mode. Nine subjects performed in a repeated measures design that presented identical errors for detection in the two modes. Results showed that sensitivity was higher in the automatic mode; the manual mode elicited a conservative response bias. NASA bipolar rating scales presented a clear picture of higher workload in the manual mode.
Assessment and Development of HF Related Safety Designs for Industrial Robots and Robotic Systems
Authors: Marton Theodore , Pulaski Joan L.
Published: January 2012

Robots and Robotic Systems, regardless of their level of automation, require formal human intervention during normal, degraded or recovery from failure processes.

Robotic applications in industry are so recent and expanding so quickly that the unique robotics related human factors safety developments and standards have not yet had a chance to be incorporated into professional educational programs or distributed to human factors engineers who are just being introduced to the field. This paper is offered to alleviate this professional growth deficiency by describing an approach and providing a format for an HF related robotic system safety assessment and development guide based on the newly released ANSI Robot and Robotic System safety standards.
A Model of Human Reaction Time to Dangerous Robot Arm Movements
Authors: Helander Martin G. , Karwan Mark H. , Etherton John
Published: January 2012

An increasing number of studies indicate that robots are the most hazardous equipment in industry. The very virtue that makes them attractive for industrial work, the programmable arm, is the cause of accidents since the arm motion is often difficult to perceive. The present paper presents a model of human reaction time and emergency behavior. The total reaction time is the sum of three elements: perception, decision making and motor response. Each of these three elements are modeled using concepts such as perceptual discriminability and single detection theory. Finally the results of an experiment is presented where the human reaction time is modeled as a function of robot arm speed.
Accident Proneness in the Industrial Setting
Authors: Mayer David L. , Jones Scott F. , Laughery Kenneth R.
Published: January 2012

The central notion of the accident proneness concept is that people exposed to equivalent hazards do not have an equal number of accidents. If people were equally accident prone, one would expect accidents to be distributed according to chance. Using accident data collected at Shell Oil Company's Manufacturing Complex in Deer Park, Texas, the present study explored the proneness concept for major (OSHA recordable) and minor accidents by comparing the observed distribution of accidents to a chance distribution. The database contains information on 7131 accidents which occurred between 1981 and 1986. The methodology used to create expected values employed a Poisson distribution and assumed that accidents are distributed randomly among the population at risk. The minor accident data was also analyzed by job family. Chi-square analyses of the differences between the expected and observed distributions were found to be statistically significant, including within each job family. The data for minor accidents indicates a striking difference between the expected and actual distributions. Many more people suffered repeat accidents than would be predicted by chance. Approximately 3.4% of the employees accounted for 21.5% of the accidents. While the differences for major accidents was statistically significant, these results are not nearly so striking. The statistical effects are largely due to five employees who were involved in three major accidents in the five year period. In the context of this very large industrial setting, the problem of individuals having repeated minor accidents is significant and merits attention in developing safety interventions.
Organizational Effectiveness of Computer-Aided Design
Authors: Harris Douglas H. , Casey Steven M.
Published: January 2012

A methodology for measuring the organizational effectiveness of computer-aided design (CAD) was developed and applied. A total of 295 of the 500 most frequent users of CAD in a major aerospace company provided data for the study. User-CAD effectiveness was found to be influenced by 43 major factors and 145 specific system and organizational issues. The 43 factors were classified into the following categories: system functions, system hardware, working environment, system reliability and consistency, user access, user support and training, and system administration. Indexes of User-CAD Effectiveness (UE) and System Availability and Reliability (AR) were combined into an Index of CAD Organizational Effectiveness (OE). Through the application of these methods and indexes, CAD system and organizational deficiencies can be diagnosed, potential high-payoff improvements can be identified, and the impact of developmental efforts can be assessed.
Confounded Experimental Designs and Human Factors Research
Authors: Weimer Jon
Published: January 2012

The use of confounded factorial designs has been seriously neglected in the human factors literature. A confounded factorial is constructed by systematically confounding blocking variables with one or more interactions which are believed to be statistically insignificant or inconsequential to the researcher. These designs offer the advantages of increased economy and power. These designs are especially useful when research is being conducted on military personnel and subjects must be selected from different military facilities, which may result in heterogeneous subject populations. A concrete example illustrates how confounding of this type can be used to the researcher's advantage through the tailored construction of a confounded design.
A Prototype Taxonomy of Training Device Visual Systems
Authors: Kincaid J. Peter , Andrews Dee H. , Gilson Richard
Published: January 2012

This paper describes and illustrates an aid (currently in prototype form) to communicate to designers and users of training devices what visual system types are currently available and appropriate for different training requirements. The aid is based on a taxonomy of visual imagery which addresses fidelity, cost and training effectiveness issues. The taxonomy includes a variety of visual scene generations from general purpose microcomputer-based imagery to dedicated state-of-the-art computer systems imagery. The scenes produced by these systems span a spectrum of video quality and costs. The aid, and the taxonomy on which it is based, is intended to help designers and the ultimate users to select relevant visual system characteristics, e.g., matching the visual system design to the training requirement. It is also intended to be useful for interdisciplinary discussion among visual engineers, computer scientists, educational specialists, human factors engineers/psychologists and program analysts. There are follow-up plans to refine the taxonomy and further develop and validate the aid.
Experiences with an Integrated Voice and Text Message Service
Authors: Riley Christine A.
Published: January 2012

An integrated voice and text message system has been provided to members of our research organization as part of an experimental system that provides our everyday communications services. The message service answers telephone calls, and the resulting messages are included in a standard electronic mailbox. Both voice and text messages are accessible from either the telephone or a terminal. Message retrieval and message management from the terminal are used extensively for voice messages as well as text messages. The telephone, while often convenient for retrieving voice messages, does not provide an attractive user interface for service control. Users neither use nor remember how to use many of the service features. The terminal, with its visual, menu-driven interface, is much more usable for service control. We believe that both our text and voice message services have been enhanced by their integration. We have also observed that the display terminal provides a very effective interface to managing voice communications services.
Callers' Perceptions of Post-Dialing Delays: The Effects of a New Signaling Technology
Authors: Lupker Stephen J. , Fleet Gregory J.
Published: January 2012

One benefit of Common-Channel Signaling (CCS), a new signaling system developed for telephone network applications, would be greatly reduced post-dialing delays. The question addressed was whether unilateral introduction of CCS in either the toll or local network would negatively affect caller behavior in the other network. Results indicate that a CCS toll network would increase caller impatience and abandonments on local calls but not vice versa. Implications of this effect are considered and felt to be far outweighed by the benefits of the CCS system.
Similarities and Differences in the Implicit Causal Models of Faculty and Students
Authors: Porter David B.
Published: January 2012

Do faculty members and students share the same underlying cognitive models? A specially-developed causal matrix was completed by 15 faculty members of the Department of Behavioral Sciences and 32 students enrolled in Introductory Psychology. Analyses of results suggest marked differences in the implicit models of these two groups. Compared to faculty, students do not differentiate causes from effects, generally overrate the number and strength of causal relationships, and include recursive relationships in their modal model. Several pedagogical implications of these findings are discussed.
Laboratory Exercises in Human Factors at the Undergraduate Level
Authors: Miller David A. , Shealy Jasper E.
Published: January 2012

This paper is an overview of a series of laboratory procedures and exercises used to demonstrate basic human factors principles to the undergraduate student. The basic topics covered are presented along with a description of a few of the laboratory exercises available. For each exercise, a brief description of the objective, methodology and data analysis is included with a discussion of any special hardware or software requirements. Additional laboratory aids discussed include hardware, software and teaching aids.
Muscle Strength Assessment from the EMG Frequency Spectrum
Authors: Jung Eui S.
Published: January 2012

Assessment of a worker's strength is of great interest when evaluating the worker's ability to safely perform a job. Many previous studies have shown that surface electromyogram EMG amplitudes correlate well with muscle force. The present study furthered this concept by using EMG power spectra to achieve a quantified representation of true strength capability. Two groups of male subjects performed isometric elbow flexions while EMG was obtained from the right belly of biceps brachii. One group exercised their arms regularly while the other not. Six different levels of graded maximum voluntary contraction (%MVC) were selected to examine the relations between muscle tension and the mean power frequency (MPF) resulting from EMG power spectra. Resultant MPF's ranged between 50Hz and 70Hz in agreement with previous research results. Two-way ANOVA showed that, in the trained group, a significant increase in the MPF was found at near maximum contractions, whereas the other group failed to show any difference. Further analysis revealed that this increase in MPF was mainly caused by the power increase in the higher bandwidth (70—100Hz). A significant variation between subjects in both groups was also observed.
Quantifying the Precision of Biomechanical Calculations using Experimental Data
Authors: Tracy M. , Corlett E.N.
Published: January 2012

Biomechanical calculations are a useful tool to evaluate the severity of manual materials handling tasks. The exactness of the calculated forces depends on a number of factors. On one level is the precision of the inputs such as postural data and the force exerted by the operator. At another level is the exactitude of the biomechanical model itself. The effect of the imprecision of each factor upon the final result can be calculated so that on one hand, the range of values within which the final result is likely to fall is known, and on the other hand, the importance of each factor can be assessed, by comparing the standard deviation of one or more factors with the standard deviation of the result.

Calculations of forces on the low back have been carried out in the laboratory using an optical scanner (CODA-3) to record posture on-line to a computer, as well as a handle equipped with strain gauges to record the force exerted. The program automatically carries out biomechanical calculations from these inputs. It takes into account the uncertainties on muscle lever arms and intra-abdominal pressure, using mean values for these and estimating the confidence limits within which the calculated low-back forces will lie, given the variance of one or more of the inputs.
Advanced Human Factors Engineering Tool Technologies
Authors: Permenter Kathryn E. , Fleger Stephen A. , Malone Thomas B.
Published: January 2012

This paper presents the results of a study to identify the human factors engineering (HFE) technologies or tools presently used, and projected for use, by HFE specialists. Both traditional and advanced tools were candidates for inclusion in the study, although emphasis of the study was placed on advanced computer applications. Human factors practitioners representing the government, academia and private industry were surveyed to identify those tools most frequently used or viewed as most important for conducting HFE related work. If advanced tool capabilities did not meet existing job requirements, the specialists identified the types of tools they would like to see developed to fill the existing technology gaps. To facilitate the inclusion of new technologies as they become available, and to aid in the search and retrieval of a tool's capabilities, information obtained on the tools was entered into a database. The survey resulted in the identification of 88 advanced tools. The results of the study suggest that although a large number of tools presently exist that are capable of supporting human factors specialists in the practice of their profession, the HFE community needs additional tools, especially those configured to run on a desktop microcomputer. Future emphasis in tool development should focus on expert systems, human factors database compendiums, computer-assisted design (CAD) applications, workload prediction tools, and automated task analysis programs.
The Design and Development of a Crew Display Demonstrator
Authors: Baum David R. , Schaefer Raymond W. , Mikula Mark B.
Published: January 2012

The U.S. Army Tank Automotive Command (TACOM) has developed a crewstation design tool to aid in defining crew-system interfaces in new or improved ground combat vehicles. The crew display demonstrator (CDD) provides a capability to rapidly reconfigure physical and functional characteristics of an operator station's displays, controls, and interactive dialog features. The CDD consists of a reconfigurable crew-in-the-loop simulation, including vehicle subsystems and tactical environments, and two generic crewstations. The demonstrator is a full-mission, fixed-base combat vehicle simulator capable of representing a wide range of operator interfaces. The crew operates the demonstrator vehicle in a simulated environment while conducting a mission against an interactive threat. TACOM plans to use the CDD to filter functional requirements and performance specifications for the Abrams Tank, the Bradley Fighting Vehicle, and the Armored Family of Vehicles. Thus, the demonstrator will enable early human factors consideration and influence in the upgrade and design of ground combat vehicle systems.
STALL: A Simple Model for Workload Analysis in Early System Development
Authors: Chubb Gerald P. , Stodolsky Noreen , Fleming Warren D. , Hassoun John A.
Published: January 2012

The Saturation of Tactical Aviator Load Limits (STALL) is defined as the intersection of asymptotically high and low load limits. In a closed queuing system consisting of M homogeneous demand generators, it has been shown that response time becomes asymptotically linear as M increases. This provides a quantitative basis for specifying the saturation point if one knows both arrival rate and service rate (the inverse of task duration).

Early in system development, one can typically estimate arrival rates based on mission analyses. But task durations cannot be estimated until procedures have been defined, based on system design. At this stage, it is useful to determine the design requirements. Given the imposed load, how fast must servicing be to keep up with demand? Logically, service rates must exceed arrival rates, but the question is: by how much? Two related criteria can apply: the number of backlogged demands, or the system response time. STALL computes statistics for both.

Preliminary model validation has been accomplished, using simulation runs to study model robustness to systematic violations of assumptions. Predictive validity depends on being able to demonstrate that the assumptions are valid in a particular application. The simulations demonstrate what can happen when that match is not successfully achieved. These studies demonstrated that the predictions will typically be most robust for an over-saturated system. The model is least sensitive to violations of the servicing assumptions. Furthermore, it is easy to relax the assumption of homogeneous demand generators by developing planned model extensions.
The Development of a Spatial Orientation Task for Inclusion in the Criterion Task Set (CTS)
Authors: Polzella Donald J. , Masline Philip J. , Amell John R. , Perez William A. , Ramsey Eric G.
Published: January 2012

Twelve subjects performed the airplane task, a test of spatial ability, in order to determine whether or not the task is suitable for inclusion in the CTS battery. Subjects performed 12 trials of the task on four consecutive days. Both performance and subjective measures were recorded. Three significantly different loading levels were obtained using the rear, front, and bottom views of the plane. It was concluded that the airplane task appears to be suitable for inclusion in the CTS.
A Multidimensional Scaling Analysis of Subjective Workload Assessment Technique (SWAT) Ratings of the Criterion Task Set (CTS)
Authors: Polzella Donald J. , Reid Gary B.
Published: January 2012

A nonmetric weighted multidimensional scaling (MDS) procedure was used to analyze Subjective Workload Assessment Technique (SWAT) ratings of the Criterion Task Set (CTS). The results indicated that over 94 percent of the variability in SWAT ratings of CTS tasks could be represented in two orthogonal dimensions: response time and task effort.
Relationship between Criterion Task Set Performance and the Personality Variables of Sensation Seeking and Stimulus Screening
Authors: Gilliland Kirby , Schlegel Robert , Dannels Sharon
Published: January 2012

The purpose of this study was to demonstrate the utility of the Criterion Task Set (CTS) as a method for personality theory testing. Subjects in a large CTS standardization study were administered the Sensation Seeking scale and the Stimulus Screening scale, two personality dimensions based theoretically on perceptual or biological processes that are believed to mediate task performance. Results indicated that high sensation seekers respond faster, but not necessarily more accurately, than low sensation seekers to central processing tasks. No differences were found for input/perceptual or motor/output tasks. Also, no differences were found between screeners and nonscreeners for any CTS tasks. The results of this study suggest that the CTS can be used profitably by personality researchers to test the basic assumptions of the theories of some personality dimensions.
Human Factors Considerations for Enhancing Performance in the Naval Airship
Authors: Leveton Lauren B. , Drum Bethany H. , Engel Peter , O'Donohue Timothy K.
Published: January 2012

The purpose of this research and review effort was to make recommendations for enhancing human performance on a conceptual airship under consideration for maritime use by the U.S. Navy. The major intent was to determine an optimal work/rest schedule and corresponding crew size (See Figure 1). These recommendations assumed an inflight mission duration of 30 days with crew exchange after the mission is completed, continuous operations throughout the mission, and certain pre-determined crew positions. Based on an analysis of analogous systems and review of state-of-the-art research, recommendations for optimal and alternative work/rest cycles were made and the impact on crew size was identified. The authors concluded that a specifically sized crew can maintain acceptable levels of performance during airship missions of 30 to 60 days duration if an appropriate work/rest schedule is followed and minimum habitability requirements are met. Accordingly, recommendations for habitability requirements were made for the following areas: volume, temperature and humidity, lighting, noise and vibration, decor, privacy, personal hygiene and waste management, food, medical support, and leisure and recreation.
Airborne Message Entry by Voice Recognition
Authors: Skriver Christian P.
Published: January 2012

This report presents the results of an experiment that measured performance in a simulated ASW message entry task with two modes of data input—vocal and manual. The subjects (Ss) were 12 Naval enlisted men. The independent variable was message data entry mode—vocal or manual. The dependent variables were: time to enter 20 lines of text, data entry errors that were corrected by the Ss, and errors that remained undetected. All Ss were trained to use the voice recognition system with a 100 word vocabulary set. The task was for the S to read one line of message text from a display and then re-enter the text below the displayed text via either voice recognizer or keyboard until 20 lines of text had been entered. Keyboard entry was found to be slightly faster (11%) than voice recognition input. While the number of initial errors (corrected) in the vocal input mode was over three times greater than the number for manual input, the remaining input errors (uncorrected) were about the same.
Information Transfer in Pilots' Use of a Collision Avoidance System
Authors: Chappell Sheryl L. , Scott Barry C. , Billings Charles E.
Published: January 2012

This paper describes a study of pilots' use of the Traffic-alert and Collision Avoidance System. Three levels of information on the location of other air traffic were presented to different groups of airline pilots. (These levels represent the approaches taken by several airlines who have installed the collision avoidance system for an in-service evaluation.) Current airline flight crews flew a Boeing 727 simulator for eight flights with a set of encounters with other aircraft.

To ensure safe separation from the approaching aircraft, the collision avoidance system commands a climb, a descent, or a reduction in rate of climb or descent. Aircraft separation was effective when the system was in use; no aircraft came within 200 feet vertically and 1000 feet horizontally.

No measure of response time showed performance effects across display conditions. Response accuracy, as measured by the overshoot in rate of climb or descent, was significant: the mean for condition 1 (no traffic information) was 2246 feet/minute, condition 2 1220 feet/minute, and condition 3 1304 feet/minute (F=4.57, df=2,64, p<.05). However there were no resultant differences in the amount of altitude change.

No learning effects were observed. Differences in flight experience did not contribute to the performance difference found.

The results of this research represent pilot behavior when introduced to the Traffic-alert and Collision Avoidance System. The findings of this program also have more fundamental importance in addressing how much and in what manner information should be presented to flight crews.
An Evaluation of Display/Control Gain
Authors: Arnaut Lynn Y. , Greenstein Joel S.
Published: January 2012

Two studies were conducted to evaluate the adequacy of identifying the optimum display/control gain for an interface as a method of control-display interface optimization. The first study examined the effects of changes in both the maximum control input and the display width on target acquisition performance with a touch tablet and a trackball. The second study evaluated the effects of changes in the display amplitude, the display target width, and the control amplitude. Results from both studies indicate that gain is an insufficient specification for performance. In addition, the inadequacy of Fitts' Law in this context is discussed.
A Comparison of Cursor Control Devices on a Graphics Editing Task
Authors: Epps Brian W.
Published: January 2012

Six cursor control devices (absolute touchpad, mouse, trackball, relative touchpad, displacement joystick, and force joystick) were compared on seven graphics editing tasks. Analysis of subjects' performance data showed better task completion times (TCT) for the trackball and mouse than the remaining four devices. Preference rankings by subjects reflected the performance results.
Internal Trunk-Loading Sequence Responses to Lifting Motions
Authors: Marras W. S. , Reilly C. H.
Published: January 2012

Many models have attempted to describe the forces which are experienced by the spine during work. However, most of these previous efforts have ignored the effects of trunk motion upon the spine loading process. This study observes the internal trunk loading key-event-times which occur when the trunk is moving at different angular velocities. These key-event times are statistically evaluated and used to form networks of event-time sequences which occur under the various velocity conditions. The significance of these sequences to spine loading is discussed.
Dynamic Lifting Strengths of Male and Female Teams: A Comparative Study
Authors: Karwowski Waldemar
Published: January 2012

The objective of this study was to compare dynamic lifting strengths of females and males working in teams of two and three members. The experimental data from two laboratory experiments was used for the purpose of statistical comparison of team strength values for dynamic back extension and dynamic lifting strengths. 15 two-member teams, all male and all female, and 20 three-member teams, all male and all female, participated in the study. Comparison of the team strengths for males and females indicates that on the average, female 2-person strengths account for about 65% and 62% of that of males for dynamic lift and back extension, respectively. For the teams of three people, females are weaker than males by about 28% and 21%, with respect to dynamic lift and back extension strength measures, respectively.
Aerospace Applications of Image Development Language
Authors: Gomberg Bruce Foster , Amberden Bruce , Pullen Ken
Published: January 2012

The Avionics Concept Evaluation Simulator (ACES) Laboratory has developed a rapidly reconfigurable real-time avionics simulation package that can be customized to specific research and development requirements. An essential component of the simulation is a unique graphics model named Image Development Language (IDL). IDL is a Lockheed proprietary, Fortran-based, graphics-imaging language that enables the human factors engineer or designer to create interactive real-time graphics and images in a short time, with relative ease, and with little or no programming expertise. Applications of IDL in human factors research and development in the aerospace community are discussed.
Industrial Accidents: Does Age Matter?
Authors: Shahani Comila
Published: January 2012

This study examined the relationship between risk of accident involvement and the aging process. It was predicted that the relationships between age and accident frequency and severity would differ depending upon job context. The study also examined the extent to which progressive selection was a factor. 7,131 accidents that occurred over a five year span in a large Southwestern petrochemical facility were analyzed. In addition, information about age and employment history was obtained for the 3,015 employees at this plant. There were no differences in the proportions of employees in different age groups across job families indicating progressive selection was not a factor in this workforce. Younger workers had higher overall accident rates than older employees; but there were few differences between them in the proportion of severe accidents incurred. The relationship between age and accident frequency and severity did not differ across job families (except in the oldest age group, where the accident frequency rate declined for two of the five job families).
Age Differences in Judgements of Vehicle Velocity and Distance
Authors: Scialfa Charles T. , Lyman Brian J. , Kline Donald W. , Kosnik William
Published: January 2012

The purpose of this study was to determine if older adults have more difficulty than younger adults in judging either the distance or speed of approaching vehicles. Eighteen elderly and 27 younger adults made judgements of the speed and distance of a video-taped automobile. Velocity judgements were made of 5 s segments of the car moving at 20, 30, 40, 50, and 60 mph. Distance judgements were based on 5 static sequences of the same test vehicle at 190, 235, 300, 360, and 480 ft. It was found that older women gave significantly higher estimates of car velocity than did younger ones. Older males also gave disproportionately high estimates of the car's distance. To the extent that these simulation data can be generalized to real-life settings, they suggest that older drivers and pedestrians (particularly older males) would view it as relatively safer than younger drivers to enter or cross the lane of an approaching car. Future research might be directed to a determination of age differences in distance perception under three-dimensional viewing conditions.