bluuebunny/crossref_metadata_2025_split huggingface dataset:
Human Factors in Support of the Coast Guard Advanced Marine Vessels Test and Evaluation Effort
Authors: Jones D. Todd 
Published: January 2012

During the past two (2) years the U. S. Coast Guard's Office of Research and Development has conducted numerous operational evaluations of “advanced marine vessels” (AMV). Among these are: Small Wetted Area Twin Hull (SWATH); Hydrofoil; and Surface Effect Ships (SES). This paper outlines the broad-based human factors RDT&E effort to support Coast Guard AMV test and evaluation needs to: Improve existing AMV vessel designs and vessel systems through Human Factors Engineered systems designs, Examine and assess AMV concepts and key subsystems to determine man/ machine problems and possible solutions, Develop, if necessary, new capabilities to monitor, control, and correct Human Factors Engineering problems uncovered during further AMV tests and evaluations, and Test and evaluate new and existing AMVs and technology systems and subsystems to determine their impact on the man/ machine interface. The generation and distribution of new and available HFE technical data to the AMV T&E team (and vessel designers/ users) as necessary, aid to the AMV T&E team (and the user) in the integration of HFE technology to the AMV end product represent key deliverables of this research effort. This research does not address a single marine vehicle, system concept, or Coast Guard program, but is structured to provide the framework for identifying, developing, assessing, and disseminating human factors technology in support of the AMV test and evaluation program. Current research efforts and results will be discussed.
Measurement of VDT Operator Performance, Eye Scanning Behavior and Pupil Diameter Changes
Authors: Zwahlen Helmut T. 
Published: January 2012

This exploratory study investigated the performance, the eye scanning behavior and the pupil diameter of three VDT operators (experienced typists) on three different days for three hours each day. A Gulf & Western, Applied Science Laboratory 1998 computer controlled eye monitor system was used to collect and analyze the eye scanning and pupil diameter data. A data entry task and a file maintenance/editing task (previously developed and used by NIOSH) were used. The results of this exploratory study indicate that the percentage of time the VDT operators look at the screen are rather low for both tasks (avg. 14.4% looking at the screen for the data entry task, avg. 34.1% looking at the screen for the file maintenance/editing task). Based upon the results of this exploratory study we may conclude that the percentage of time an operator looks at the screen for both a data entry and a file maintenance/editing task is relatively small and thus there is a question whether the many reported complaints about eye troubles such as eye strain, eye pain, and irritated eyes are really caused by the screen itself or are actually due to highly rigid and monotonous job tasks, the overall VDT work station design, postural, environmental, psychological, and social factors.
Tactile Inspection Performance with and without Gloves
Authors: Desai Siddharth , Konz Stephan 
Published: January 2012

A firm whose inspectors tactually inspected hydraulic hose was interested whether gloves would help or hinder their inspectors. Eight female subjects, while blindfolded, each inspected 600 hoses–150 for each of the four glove conditions (bare hand, surgeon's gloves, Playtex gloves, and vinyl-impregnated gloves). The subjects indicated whether the hose was acceptable, defective due to diameter, or defective due to surface roughness. The data was divided into that obtained when the hoses were acceptable and that when there was a defect. For good hoses, gloves did not affect error rate for either diameter defects or surface defects. For defective hoses, gloves did not affect error rate for either diameter defects or surface defects. Thus the decision whether or not to wear gloves can be made on other criteria (such as protection of the hand vs abrasion or chemicals). A signal detection analysis was made. Some other ergonomic suggestions for improved inspection performance are given.
Heating Pads: Human Factors Traps for Designers and Users
Authors: Jahns Dieter W. 
Published: January 2012

Every year substantial amounts of property damage and numerous personal injuries result from failures of electric heating pads. This is a paradoxical situation considering that the intended product-function relates to the simple, safe, and reliable therapeutic application of heat to the human body. An investigation was conducted to determine whether traditional engineering criteria and human factors criteria were in conflict in the design of heating pads. The investigation revealed that the designers of heating pads have a tendency to overcome problems in hardware reliability by specifying how humans should behave relative to their product. Even heating pads that are Underwriters Laboratory (UL) listed contain user instructions which are unlikely to be followed under circumstances of normal use. The paper summarizes the functional design of heating pads, current instructions for their use, and applicable human factors considerations. An alternate approach to heating pad design is proposed which, if implemented, should prevent us from trading-in our heating pads for hot-water bottles. Beyond that, however, the paper serves as an example of how the application of human factors engineering principles can serve the goals of product safety and liability prevention.
Graphics Prototyping Environment (GRAPE)
Authors: Fish Robert S. 
Published: January 2012

To produce a graphically oriented interactive interface to an engineering system, some method of displaying and interacting with both geographic, iconic, and textual information about an engineering domain is needed. However, generating effective requirements for such a system is not a completely straightforward process. There are many aspects of the interactive process for which an optimal or even adequate specification is not currently possible. This is because of the inherent complexity of completely describing an image compounded from several independent parts, each of which can change as a function of the stage and content of the interaction. An alternative to the approach of attempting an a priori specification of a graphics interface is to build a systems engineering and prototyping tool that would allow the simulation of such an interface. With such a tool, a graphics interface could be evaluated during the requirements generation stage and the requirements tailored as needed. Moreover, the simulation itself would provide a set of explicit requirements that are inherently implementable. A number of characteristics are desirable in such a tool. These include device independence, so that users are not tied to specific hardware, a scripting facility, so that user written scripts can drive the interface, parameterized graphics descriptions, so that graphics objects may be created and stored in a invocation independent fashion, and a database interface, so that data can be extracted and displayed from an application specific database. In addition, provision must be made for the different styles of interface design so that demands for windowing and other complex features can be accommodated. A demonstration of portions of such a tool has been built and an effort is underway to complete implementation. At the center of GRAPE is an abstract machine that carries out its abstract operations. Six high level languages, a Script Language (SL), a Command Definition Language (CDL), an Object Description Language (ODL), a Menu Definition Language (MDL), a Form and Table Definition Language (FTDL), and a Device Interface Language (DIL), are interpreted into operations of this abstract machine. Along with window and file managers, these languages provide the facility for an interface designer to specify command structures, graphics objects, menu structures and content, form and table layouts, and a script that ties these elements together into a simulated interface. The simulation will run on any device specifiable in the Device Interface Language. The output of the abstract machine running a script is a simulation of the complete interface, including i/o, although response time is dependent on the hardware utilized.
Feedback and Key Discrimination on Membrane Keypads
Authors: Roe Cynthia J. , Muto William H. , Blake Tyler 
Published: January 2012

This study investigated the effects of visual and tactile key discrimination and kinesthetic and auditory feedback on membrane keypads. More specifically, metal domes, embossed key edges and tone were examined. Fortyeight subjects were used in a 2 × 2 × 2 factorial design with two levels of key discrimination (with and without embossed key edges), two levels of kinesthetic feedback (with and without metal domes), and two levels of auditory feedback (with and without a 1000 Hz tone). Several types of preference scales along with keying time and error rate were used as comparative measures. Results indicated that key discrimination provided by embossed key edges and feedback provided by metal domes and auditory tones had significant effect on keying performance and operator ratings of membrane keypads. Auditory feedback paired with tactile and/or kinesthetic feedback yielded the best performance and preference scores.
The Effect of an Optical Aid on the Visual Fatigue and on the Performance of VDT Operators
Authors: Stuart Mark Alan 
Published: January 2012

The main objective of this study was to investigate a method of reducing the amount of visual fatigue which is often associated with VDT usage. Specifically studied was the effect of the provision of refractive power on various indicants of visual fatigue (distant focus time, eye-blink rates, and visual acuity), visual-search performance on a computer, and evaluative responses on a questionnaire. Refractive power was provided with the use of nonprescription reading glass. Two different character sizes (4.8 and 5.8 mm) and two different viewing distances (508 and 666 mm) were also studied to determine if an increase in the visual angle of characters would result in significant improvements. After analyzing the data with a repeated measures analysis of variance, it was determined that the use of the reading glasses resulted in significantly ( p < 0.05) lower: distant focus times and left-eye acuity measurements. There were no significant benefits on other measurements taken. The glasses resulted in fewer visual complaints on several questionnaire responses, but there was not a strong preference for the glasses. There were virtually no differences between the two different character sizes and viewing distances studied. It is concluded that if the reading glasses are used under certain conditions (the user is nonastigmatic and has at least 20/20 vision - either corrected or uncorrected) then they may help reduce some of the visual fatigue associated with VDT usage for operators in the field.
The Effects of Aerial Perspective on Altitude Estimation
Authors: Patterson Michael J. , Rinalducci Edward J. 
Published: January 2012

Recent interest in the importance of visual displays within specified flight simulations and scenarios has led to increased emphasis on the identification of pertinent cues within these displays. Through the identification of these cues and their usage in altitude estimation, more effective simulation and hence training programs can be developed. The present explanatory study investigated the use of a psychophysical methodology in the evaluation of aerial perspective as a possible cue in altitude estimation. Specifically the effects of two levels of aerial perspective (present and reduced) and flight experience on estimations were examined. Based on the linear functions of log estimated vs. log actual altitude, differences were found between levels of flight experience in the aerial perspective-present condition. Subjective responses suggest that individuals are aware of the presence/absence of haze conditions and this information influences their altitude estimations.
Degradation of Performance Due to Sleep Deprivation: A Field Test
Authors: Ball C. , Funk T. , Noonan D. , Velasquez J. , Konz S. 
Published: January 2012

During a 72 h field test, two groups of elite, “ranger type” soldiers were evaluted five times (during the first 8 h, after 30 h of continuous field duty, after a rest period, after 30 more h of continuous field duty, and after a second rest). One group (7 soldiers) received two rests of 3 h each. The second group (6 soldiers) received two rests of 6 h each. Five military tasks (map reading, decoding messages, vehicle/aircraft recognition, assembly and disassembly of the M-16 rifle, and preparation of an AN/PRC radio for operation) were used. These tasks were considered by the commander to be representative of duties that the soldiers would do and were considered to be completely familiar to the soldiers. In addition, a peg into pegboard task and a subjective evaluation of fatigue questionnaire were given. There was no significant effect of time or difference between the two groups. The soldiers completed these tasks of short duration (less than 3 min) without decreasing performance—even after extended periods of sleep loss. These performance results occurred even though subjectively the soldiers reported they were tired.
A Control Model: An Alternative Interpretation of Fitts' Law
Authors: Connelly Edward M. 
Published: January 2012

Fitts' law has been universally cited as an index of difficulty or predictor of movement time (MT) for rapid aiming tasks since it was first published in 1954 (Fitts 1954). Many researchers report a remarkable correlation of Fitts' law and the observed movement times in aiming tasks. Other researchers report discrepancies, however, between observed movement time and the law, especially at low and high movement times, which correspond, respectively, to short movements to a large target, and long movements to a small target. These discrepancies suggest that while the law predicts MT well for some human motions, the true basis for the law may not be known, and, as a consequence, that there may exist conditions where its application is appropriate and yet others where different laws should be used. Fitts suggested the law as a model of the rate-limit of human information processing and movement. But this rate-limit model is not the only interpretation possible. Rapid movement of the hand to a target can be modeled from a different view-point: namely, as a control system. This paper gives the analytical results for several models: a first order model where it is assumed that the hand velocity can be directly controlled, and a second order model where it is assumed that the hand acceleration can be directly controlled. The results show that the first and second order models with the linear control-law produce a MT function with the exact form of the Fitts' law, and yet it has nothing to do with information theory.
Search Performance as a Function of Depth of Processing and Scrolling Rate
Authors: Alvarez Maria G. , Murray J. Thomas , Hakkinen Markku T. 
Published: January 2012

Most investigations of task performance as a function of the scrolling rate have focused on display characteristics (e.g. character density and line spacing) as the major class of covariats. However, a more important class of variables pertain to the user's goal or task that caused him to envoke the scrolling function. Accordingly, the focus of the present study is the impact various scrolling rates have on performance as the complexity of the user's task is varied. The complexity of a search task was varied over two levels on a Depth of Processing dimension (Cralk & Lockhart 1972) for each of three line-by-line scrolling rate conditions as well as for a paging condition in which the contents of the screen was advanced 23 lines of the 24 line display. In the semantic search condition, (high task complexity) users searched text displayed on a CRT for a word that is a member of a pre-designated category such as an animal name. This task requires that the user process each word in the display on a semantic level to determine whether or not it is a member of the target category. Also, it is argued that the semantic search task, which is less complex than a reading task, is representative of tasks for which users typically search a display. In the feature search condition, (low task complexity) users searched a CRT display for an exact match to a pre-designated target word. For this task the user need only process each word in the display to the visual feature level to determine whether or not it is the target word. Assuming that more cognitive processing time is required for the semantic search task than the feature search task, it was expected that the optimal scrolling rate for the visual search task would be faster than that obtained for the semantic search task. The preliminary results confirmed this expectation and also indicated that the paging conditon produced better performance than any of the line-by-line scrolling conditions.
Ergonomic Skills Training: Discussion of Methods Used to Improve Skill and Comfort Levels of Workers Using Video Display Terminals
Authors: Joyce Marilyn S. 
Published: January 2012

Ergonomic Skills Training is the new way of enabling workers to take responsibility for their own comfort and productivity in VDT environments. After receiving Ergonomic Skills Training, VDT users have demonstrated productivity increases, and error decreases, in a variety of applications. In addition, they have reported dramatic improvement in their health/comfort levels. The training involves the following: Short-term Memory Skills in both visual and auditory perception which serve to reduce keying and proofing errors. Physical exercises to be performed at the workstation throughout the day to prevent and/or reduce fatigue, eyestrain, muscular pain. Individual workstation adjustments to enable workers to adapt basic ergonomic principles to existing work environments and thus enhance work flow and personal comfort. This paper is a description of the training methods used and the results reported by trainers and clients.
A Methodology for Work Chair Assessment
Authors: Christensen C , Casali J. G. , Kroemer K. H. E. 
Published: January 2012

A large segment of the office work force in the United States spends a majority of their work day seated in stationary chairs. Problems with postural fatigue and related maladies are commonly associated with the neck, arms, shoulders, as well as with different portions of the back. This study was conducted in an effort to determine whether several metrics for general posture and comfort evaluation were viable specifically for work chair evaluation. These techniques were a modification of a posture measurement technique developed by Corlett, Madeley and Manenica (1979) known as Posture Targeting. In addition, three subjective rating scales were used. MANOVAs were performed on the data. Both task-type and chair-type were found to significantly influence the posture and subjective responses of the subjects in the study.
Simulators Used in Maintenance Training: A Survey
Authors: Carroll Robert J. 
Published: January 2012

Simulators are becoming an increasingly prevalent component of maintenance training curricula in the military services. The types of simulators in use and their training functions vary widely, from electronic logic boards that provide troubleshooting exercises to full scale mockups that allow students to identify component locations and practice operational checks. A survey of over 25 military and civilian maintenance training simulators was conducted to identify the types of devices currently in use, the role they play in the training environment, student/instructor attitudes toward the devices, and other factors which impact the cost/training effectiveness of maintenance simulators. Personnel surveyed included students, instructors, course managers, simulator operators, and maintenance personnel. This paper summarizes the findings of the survey, and discusses the results in light of optimizing the utilization of simulators in maintenance training.
Torque Characteristics for a Consumer Sample
Authors: Kreifeldt John G. 
Published: January 2012

A series of experiments were conducted to determine the maximum amount of torque that males and females could apply by hand to knobs of commercial products. The purpose of the experiments was to provide data suitable for the safe design and testing of a common household item. Investigations had revealed that in some instances users may have turned a knob past a point where the item became in effect a “time bomb” even though the item had been purportedly designed to withstand the torque required to do this. Further, the ability of the design to withstand the torques required to do this may also have been inadvertently tested in the quality control and inspection station of the manufacturer. Literature clearly indicates that the amount of torque that may be exerted depends on factors of knob design such as its radius, geometry, etc. Because the literature did not provide data precise enough for the present purposes a series of experiments were made to answer the specific questions. For the knob in question, and as an example of the results obtained, it was found that 14 males could exert an average of 36 inch-pounds (standard deviation of 7.2 inch-pounds) to the knob with their unaided hands and for a one time maximal effort. For the manufacturer's testing procedure in which women testers were equipped with a large radius handle tool with which to turn the knob, it was found that women could exert a one time maximum torque of 37.00 inch-lbs with the tool inserted into the knob. However, in as much as the quality control testers need to exert a torque on the order of once per minute or two, it was more realistic to measure the sustainable level that could be achieved. As an indication of what this might have been, the women were requested to exert their maximum torque ten times consecutively with a minute between efforts. The results showed that the torque level fell to 30.64 inch-lbs by the tenth trial and that furthermore the decline in torque was well fitted (correlation of 0.95) by a power function.
Improving Motorcyclists' Braking Performance: The Integrated Brake System
Authors: Mortimer Rudolf G. 
Published: January 2012

Two motorcycles were used in these tests, each of which could be operated in both integrated and separated braking modes. The motorcycles had engine displacements of 400 cc and 1100 cc. The braking test was performed by 24 riders, nine of whom were instructors in motorcycle rider courses. It was found that, on both dry and wet pavements, decelerations were significantly greater in the integrated braking mode than the separated mode when foot brakes alone were used and there were no significant differences in the frequencies with which wheels were locked between these modes. However, there was a consistent trend of fewer lockups in the integrated mode. When both brakes were used on the larger motorcycle significantly greater mean deceleration was attained in the integrated than separated mode but this was accompanied by significantly more wheel lockups in the integrated mode. The results indicated a significant advantage in braking performance with integrated brakes for the motorcycle rider course instructors and the other riders. This advantage could be expected to reduce stopping distances of motorcycles and, thus, their involvement in accidents.