bluuebunny/crossref_metadata_2025 huggingface dataset:
The Evolution of the Ageing Ovary
Authors: Motta Pietro M. , Makabe Sayoko
Published: July 2017

This review updates the three-dimensional (3-D) microanatomic evolution of the ageing human ovary in a novel dynamic fashion, taking advantage of integrated scanning, transmission, corrosion casts and correlated techniques developed by ourselves. Tissues were collected from ovaries of women (aged between 28 and 70 years) during open surgery or endoscopic procedures. Our findings are as follows: the volume of the postmenopausal ovary was about one half of that present during reproductive years; postmenopausally the ovary became progressively atrophic and fibrotic. Particularly it showed a decrease of papillae and crypts which made its surface smoother than that of premenopausal tissue. In perimenopausal women (aged 45–55 years) the superficial cells covering the ovary were irregularly polyhedral and flattened. Their cytoplasm showed few organelles and in some instances apoptotic and/or necrotic cells. These features increased in most aged ovaries. Consequently the zones of the ovarian cortex (tunica albugina) could occasionally appear as consisting of dense fibrous collagen structures. Here only a few altered and swollen small follicles could be found. In the medullary regions variously sized cysts, some of which were blood filled (corpora atretica and hemorragica), were present along with retracted scars (corpora albicantia). In older women (aged 55–70 years) follicles were never observed. Instead, areas of thick density of collagen fibres and numerous sized scars (corpora albicantia) were present. A drastic reduction of the ovarian vasculature along with thickened vessel walls was commonly found. These typical features were already noted in perimenopausal women, but to a lesser extent.

The detailed fine cell alterations of the ovary would appear to reflect the progressive decline in steroid hormone production as the ovary ages.
Some New Evolutions on the Inverse Problems in Elastodynamics
Authors: Huang Wenhu , Ma Xingrui , Niu Yuqing , Tao Liang , Du Desheng
Published: July 2017

In this paper, the research on the inverse problems in elastodynamics is summarized. Some typical and new researching results are presented, which are obtained from the inversion of ray theory, the Inverse-Born method of wave equation, the inversion of transmission matrix, the inversion of large perturbational medium parameters and the inversion of interface geometrical parameters, respectively. Some problems in this field are produced in the approaching research.
Performance Comparison of Passive Energy Dissipation Systems in Structural Applications – I: Linear Reference System
Authors: Ou Jin-Ping , Wu Bo , Soong T.T.
Published: July 2017

In this paper, an analysis is presented for the performance comparison of representative passive energy dissipation systems which have been developed and implemented in structures in recent years. They include viscous fluid dampers, viscoelastic solid dampers, metallic dampers, friction dampers, tuned mass dampers and tuned liquid dampers. A single-degree-of-freedom linear structural system is used as a standard reference system where ground excitations are simulated either as a white noise or a filtered white noise. The performance criteria are first established, followed by the formulation of computational models for each of the energy dissipators considered. For those exhibiting inherent nonlinear behavior, statistically equivalent linearized models are used for analyzing their modified dynamical properties, such as additional mass, stiffness and damping coefficients due to addition of the energy dissipators to the reference system. Finally, representative numerical models of the above six types of energy dissipators are used to make quantitative comparisons of their performances when added to the reference system by calculating their equivalent additional dynamical properties and their effectiveness in alleviating key response quantities of the system.
Formation and Strength of Crystalline Calcium Silicate Hydrate Prepared by Single Autoclaving Process
Authors: Peng Gai-Fei , Feng Nai-Qian , Chan Sammy Y.N.
Published: July 2017

Two kinds of calcium silicate paste containing tobermorite and xonotlite crystallines, were used to prepare calcium silicate hydrate products by a single autoclaving process. The mechanical strength and microstructure of these products were determined to investigate the hardening mechanism of calcium silicate hydrate material. The relationship between the forming pressure and mechanical strength and the observed microstructure revealed that the mechanical strength of this type of material is attributed to a mechanism of contact hardening. Increasing the forming pressure could enhance its mechanical strength. However, it was also found that there was an optimum forming pressure that produced the maximum mechanical strength.
Stability of Laminated C-Section Columns: A Semi-Numerical Model
Authors: Khong P.W.
Published: July 2017

This paper describes the effort to apply a semi-numerical formulation to the buckling analysis of laminated C-section column. The presented analysis is confined to the elastic buckling of axially end compressed laminated C-section column. In this method, the laminated C-section is treated as a system of three connected laminated composite panels. Assembled stiffness matrices are then integrated from the individual composite panel's stiffness. Eventually, an eigen-value problem is formed for buckling solutions. Since the theoretical formulation is seminumerical, the method can be employed to other arbitrary cross-sectional geometries of laminated columns.
Development and Evaporation of Group-Hole Nozzle Sprays under Various Surrounding and Impinging Conditions of Direct-Injection Diesel Engines
Authors: Moon S , Zhang W , Nishida K , Matsumoto Y , Gao J
Published: July 2017

In the present study, penetration and evaporation of the diesel sprays injected by a group of two closely spaced orifices (a group-hole nozzle) were investigated and compared with those of conventional single-hole nozzle sprays under various engine loads and wall-impinging conditions of direct-injection (DI) diesel engines. Both free and wall-impinging conditions were considered. The experiments were performed inside a constant-volume vessel under simulated ambient conditions for low and high engine loads of DI diesel engines. To investigate the effect of spray targeting, two impinging conditions (impingement angles of 45° and 90° with the same impingement distance) were applied. Geometry and liquid/vapour mass distributions of the evaporating diesel sprays were analysed using a laser absorption scattering (LAS) technique.

Under a free spray condition, fuel evaporation of the group-hole nozzle spray was improved compared with that of the single-hole nozzle spray at low load conditions, while it showed simultaneous deterioration in fuel evaporation and spray tip penetration at high load conditions. Jet axes deflection of the two jets from the group-hole nozzle, which generated a dense liquid region at the central region of the spray, was responsible for this deteriorated evaporation at high load conditions. Under a vertical impingement condition (impingement angle of 90°), the group-hole nozzle spray showed simultaneous improvement in spray tip penetration and fuel evaporation at both low and high load conditions from strong momentum interaction of the two jets on the impingement wall. However, this improvement from the group-hole nozzle did not appear at an inclined wall-impingement condition (impingement angle of 45°) owing to weakened and delayed momentum interaction of the two jets. Both spray tip penetration and fuel evaporation of the group-hole nozzle spray were deteriorated at the inclined wall-impinging condition.
Effect of Monomer Structure on the Cure of PMR Polyimides
Authors: Preston P.N. , Soutar I. , Woodfine B. , Hay J.N. , Stewart N.J.
Published: July 2017

Investigation of the influence that monomer structure plays in determina tion of the nature of thermoset PMR polyimides has revealed new information regarding the cross linking reaction profile and resultant resin properties. Replacement of BTDE by ODPE as dianhydride shows reduced resin T g values. Synthesis of a new series of alkylene dianilines, with increasing flexibility within the homologous series, evinces lowered cross-linking onset temperatures and T g transitions. Increasing degrees of meta catenation in extended diamines also result in lowered T g values.
Effects of Age and Practice on Attention and Stages of Information Processing Using CRT with Fixed and Variable Foreperiods
Authors: Carlton Barbara L. , Vercruyssen Max , McDowd Joan M. , Birren James E.
Published: July 2017

The results of previous investigations have found conflicting results on the locus of age-related slowing of reaction time using Additive Factors Method (Sternberg, 1969). This experiment was conducted to examine the differential effects of Additive Factors Method task manipulations using both fixed and variable foreperiod conditions with practice preceding a second day replication to quantify the interaction of these effects with skill. The results show that (1) practice is a major confounding for research involving RT tasks, (2) the locus of age effects may lie in the later response selection stage of processing, and (3) the effects of aging, practice and intra-task factors depend on the response-stimulus interval characterizing the RT task. This research has implications for improving research methodologies and understanding the nature of age-related slowing in central nervous system functions.
Weber's Ratio, Multidimensional Scaling and Incomplete Data Sets: New Light on an Old Problem
Authors: Kreifeldt J. G. , Levine S. H. , Chuang M. C.
Published: July 2017

Sensory modalities exhibit a characteristic known as Weber's ratio which remarks that when two stimuli are compared for a difference: (1) there is some minimal nonzero difference which can be differentiated and (2) this minimal difference is a nearly constant proportion of the magnitude of the stimuli. Both of these would, in a typical measurement context, appear to be system defects. We have found through simulation explorations that in fact these are apparently the characteristics required by a system designed to extract an adequate amount of information from an incomplete observation data set according to a new approach to measurement.
An Innovative Nonparametric Measure of Response Bias
Authors: Shontz William D.
Published: July 2017

A nonparametric technique for assessing the effects of response bias within the Signal Detection Theory paradigm was developed. The technique involves modification of the 2 × n table produced when rating scale data are collected under the SDT paradigm. A χ2 value computed from the modified table is used as the unit of analysis in statistical analyses. This new measure of response bias has been shown to be independent of several nonparamentric measures of sensitivity when tested under three different experimental designs.
Developing a Training Data Architecture that Ties it Altogether
Authors: Sicilia G. Thomas
Published: July 2017

Everyone involved in quantifying the human part of the defense equation has long been frustrated by lack of consistent, “reproducible” and comprehensive data. This void is especially evident in the training and performance data area. The Defense Training and Performance Data Center (TPDC) was established to help redress this problem.
Development of a Prototype Performance Measurement System for Strike Warfare Training Assessment
Authors: Martin J. I. , Breidenbach S. T. , Ciavarelli A. P.
Published: July 2017

This paper describes methods for developing automated performance measurement systems used with training ranges and simulators. A prototype automated measurement system designed to assess aircrew performance during strike warfare training is presented as an application of this methodology. Methods are also presented for displaying information which is useful in assessing student progress and for diagnosing training results.
Declarative and Procedural Knowledge in Skill Acquisition: An Aptitude — Treatment Interaction Framework for Training
Authors: Ackerman Phillip L. , Kanfer Ruth
Published: July 2017

This paper focuses on the interactions among four constructs during skill acquisition: (1) the dynamic changes in attentional demands of the task to be acquired, (2) individual differences in cognitive and intellectual abilities, (3) conative (motivational), metacognitive processes involved in changes of attentional focus, and (4) knowledge structures acquired through part-task training. An attentional model is reviewed that describes how these variables interact during three phases of skill acquisition (i.e., during declarative knowledge, knowledge compilation, and at the level of proceduralized knowledge). Empirical demonstration of the framework is provided in the context of complex skill acquisition. Supportive results from a series of empirical studies are reviewed.
The Formative Evaluation of a Decision Support System for Designing Training Devices
Authors: Singer Michael J. , Mumaw Randall J. , Gilligan Elizabeth L.
Published: July 2017

Formative evaluation in the broadest sense refers to the measurement of some system in order to make direct and immediate differences in the procedures, mechanisms, and goals of that system during development. The objective of this formative evaluation is to address three areas: 1) increase our understanding of how the targeted users make decisions, 2) train the user about how the system makes decisions and presents information, and 3) develop information about interface and modeling changes needed in the system. What is needed in the design of decision aids is an understanding of both how the user perceives the decision process, and how the decisions actually could be effectively made. Both of these issues must be addressed before the user will accept and use the decision aid. The system also needs to be able to accept and use the information that the user considers necessary, as well as to present both recommendations and supporting information in acceptable formats. We have applied a structured interview within our formative evaluation process as a basis for integrating the user in the develop, revise, and deliver cycle. The structured interview was conducted on-line, demonstrating what the system does while explanations of how it works are provided. The responses have provided information about whether the user thinks the system addresses the correct issues, the users agreement with the system analyses, and a report of the users decision processes. By including the user in the review of the developing system, the design of the prototype more accurately reflects the user's decision processes, as well as providing more usable output. This study will provide some insight about one method for evaluating decision aids early in the development process.
Automaticity and the Transfer of Mental Rotation Skills
Authors: Grose Eric M. , Damos Diane L.
Published: July 2017

Two experiments are presented that examine automaticity and transfer of mental rotation skills. The data from these experiments were analyzed using a curve-fitting technique that represents a departure from traditional methods used to analyze transfer. The first experiment demonstrated significant positive transfer from one letter stimulus to another. The second experiment examined the transfer of rotation skills from a letter to an abstract shape. This experiment demonstrated a reduced amount of transfer from letters to an abstract shape. Both experiments indicated that mental rotation skills may become automatic with practice.
Breaking Out of Conceptual/Methodological Traps: A Case Study from Research on the Computer Mediated Classroom
Authors: Richards Robert E.
Published: July 2017

This paper describes several lessons learned in the process of getting Computer Conferencing to work for Army Training. One methodological lesson was to better assess the maturity of the phenomenon to be studied and utilize formative evaluation rather than experimentation for immature areas of study. Another lesson was to not over-borrow from prevailing conceptual frameworks as they may be inappropriate for a new context. Some specifics, in case study form, are given to illustrate these lessons learned.
Course Development for the Computer Mediated Classroom
Authors: Hahn Heidi Ann
Published: July 2017

This paper discusses considerations for designing instructional materials for the computer mediated classroom. Specifically, the topics of group versus individual instruction, information processing, media/method tradeoffs, and associated costs were addressed.
Instructor Training for the Computer Mediated Classroom
Authors: Kaplan Bruce L. , Jones Mark K.
Published: July 2017

This paper explores the issues and dilemmas faced in designing and delivering instructor training for Army engineers to teach in a computer mediated classroom. It presents an account of the design and development and implementation processes, including the evaluation methodology and lessons. Differences between the roles of instructional staff in the computer conference and traditional school environment are also discussed.
Power Window Control Location Stereotypes
Authors: Kweon O'Seong , Schlegel Robert E. , Purswell Jerry L.
Published: July 2017

A paper-and-pencil survey instrument and an operational test were used to assess stereotype strength for automobile power window controls. Control panel layout (square vs. linear) and mounting plane were examined along with stereotype differences between subjects with technical backgrounds and those with non-technical backgrounds.

A total of 273 participants ranging in age from 16 to 50 completed the survey instrument which requested responses to questions about which control was expected to activate a specified window. Subject preference for a particular control configuration was also solicited. A square control layout mounted on the instrument panel exhibited the strongest stereotype (94% of consistent responses for a single pattern) although it was the least preferred (22%). A square configuration mounted on the door panel possessed the second strongest stereotype (67% and 28% of consistent responses for the top two response patterns) and the highest preference (47%). A linear configuration mounted on the door panel exhibited a weaker stereotype (57% and 36% of consistent responses for the top two response patterns) and was preferred by 31% of the subjects. Preference tended to follow familiarity with controls in existing vehicles rather than ease of use or isomorphic arrangement.

Twenty-four of the survey participants were also tested using actual power window controls mounted in a vehicle mockup. The subject's task involved moving the left hand as quickly as possible from the steering wheel to the subject's selected control upon presentation of a pictorial or verbal cue to raise or lower a specific window. Cue presentation and measurement of reaction time and movement time were provided by a PC. The square control layout mounted on the instrument panel was superior in terms of response time, stereotype strength and response consistency.
Components of Perceived Risk for Consumer Products
Authors: Vaubel Kent P. , Young Stephen L.
Published: July 2017

The present study examined the underlying dimensions associated with perceived risk for consumer products. Eighty undergraduate students evaluated 40 products using seventeen rating questions. Principal components analysis was then performed on the ratings. Results indicated the presence of three underlying components or dimensions along which the products varied. The first component dealt with qualitative aspects of the risks associated with a product, such as the degree to which potential hazards were known (or knowable) and the immediacy of their onset. The second component concerned subjects' familiarity with the product. The third component was associated with quantitative aspects of the risks and reflected notions about the magnitude of the potential harm (in terms of the number of potential victims) that might be incurred as a result of using the product. Subsequent regression analyses revealed that each dimension was significantly related to subjects' rated intent to act cautiously with a product. Overall, these results suggest that people do not perceive consumer products unidimensionally. Rather, such perceptions are best conceptualized as reflecting multiple underlying facets.
Operation of Controls on Everyday Products
Authors: Schoorlemmer W. , Kanis H.
Published: July 2017

Previous research shows that the self-reliance of physically impaired people can be seriously jeopardized by their inability to operate controls on everyday products. In the research reported in this paper a study is made into the operational difficulties faced by people suffering from Parkinson's disease, from spasticism, from visual impairments, and by physically non-impaired subjects.

This paper reports the forces that can be exerted by these subjects, the way they actually manipulate controls, and the operational difficulties the subjects experience including both the force exertion and other operational difficulties. Finally, design implications are briefly looked into.
Connoted Quantity of Food-Label Modifier Terms
Authors: Kalsher Michael J. , Wogalter Michael S. , Gilbert Carolyn M.
Published: July 2017

This descriptive study examined a set of modifier terms (e.g., reduced, enriched) that might be used to indicate amounts of substances in food products. In the context of a mock shopping task, participants were asked to complete a survey that assessed the implied meaning of each of 55 terms, 28 connoting varying degrees of decrease and 27 connoting increase. For each set of modifier terms, participants estimated the amount that each term implied and the likelihood that they would purchase a food product with the term paired with substances that they were advised to consume or avoid. The results showed that the terms used in this study connoted a broad range of quantities. Several alternative terms not currently used or under consideration by the U.S. Food and Drug Administration may be effective in helping consumers make finer distinctions among products and, presumably, wiser purchase decisions. The results also suggest that caution be exercised when selecting modifier terms since some terms are less consistent in their connoted meaning than others. Thus, instead of arbitrarily selecting modifier terms and then initiating expensive, large-scale nutrition training programs to train the public, it is recommended that a limited number of modifier terms based on their extant meaning to a broad segment of the population should be used. Future research on developing an optimal set of modifier terms is discussed.
The Dictionary for Human Factors/Ergonomics: A Significant Reference Work in Human Factors
Authors: Stramler James H.
Published: July 2017

Terminology is probably the most important factor in learning or working in any field. The Dictionary for Human Factors/Ergonomics is the result of a major effort to provide the first single source containing a large proportion of the terms used in all areas of human factors/ergonomics. A number of benefits accrue from having this work available. Some of the problems encountered in writing this dictionary are discussed. The ultimate goal for this work is to serve as a terminology standard in human factors/ergonomics.
A Human Factors Tool Kit
Authors: Kline Paul B. , McAlindon Peter J.
Published: July 2017

The variety of tools and techniques available to help the human factors professional apply basic research data to the real world is constantly increasing. Despite this, there are few available sources of objective information about tools. Most of the information available to practitioners comes in the form of advertisements and professional contacts. Unfortunately, the emphasis is often on newest or latest when less expensive ‘low tech’ solutions may work just as well. Moreover, there are likely tools or techniques known to practitioners in one area of the human factors that are unknown to individuals in other areas of the discipline. The current effort seeks to identify tools useful to the human factors professional and to increase awareness of existing tools which can facilitate the application of Human Factors data to the real world. An added emphasis was placed on those tools which can be employed easily and inexpensively.
Some Ergonomic Considerations in the Design of Materal Handling Devices
Authors: Resnick Marc L. , Chaffin Don B.
Published: July 2017

Material handling devices (MHD's) are being proliferated in factory workplaces to prevent workers from being injured due to the lifting of heavy loads. These devices require exertions which have not been adequately studied from an ergonomic perspective. Jobs with MHDs often require complex 3-dimensional movements and loaded axial rotation. One type of MHD, an articulated arm, was used to investigate the effects of inertial load, arm joint friction, and positioning accuracy requirements. The kinematic variables of peak push and pull hand forces, velocities, and accelerations were measured or computed in both a task that allowed sagittally symmetric postures as well as one in which loaded axial torso rotation was required. Greater inertial loads increased the peak push and pull hand forces in all cases by an average of 20%. The activation of a 40 psi brake at both joints of the articulated arm increased the peak hand forces by about 40% on average and decreased the peak velocities and accelerations in both tasks by about 20% and 15% respectively. The effects of positioning accuracy required were not as universal. There was a 10% decrease in peak velocity and acceleration for smaller target size in the sagittally symmetric task but no significant effect in the torso twisting task. The study generated some guidelines for the implementation of MHD's, and suggests some areas where further research is required.
Fatigue Effect on Lifting Acceleration in Frequent Lifting
Authors: Kim Y. , Lee K. , Aghazadeh F.
Published: July 2017

The objective of this study was to investigate the effects of fatigue, caused by frequent manual lifting, on lifting velocity and lifting acceleration. Ten male volunteers performed lifting at a rate of 4 times per minute, continuously, for two hours using the free-style posture. A box (30cm × 30cm × 20cm) with a fixed weight (15.9 kg) was used as the load for lifting. Heart rate, oxygen consumption, and EMG were also measured to estimate the level of fatigue. The posture as well as acceleration was recorded. The results show that the lifting acceleration at the end of two hour increased significantly (20%, p < 0.001) compared to the acceleration after fifteen minutes of lifting. It was also found that subjects changed their lifting postures as the result of fatigue. All subjects also indicated pain in their upper legs and the lower back at the conclusion of the experiment.
Maximum Acceptable Weights of Lift for Common Coal Mine Supply Items
Authors: Gallagher Sean , Hamrick Christopher A.
Published: July 2017

A series of psychophysical lifting studies was conducted to establish maximum acceptable weights of lift (MAWL) for three supply items commonly handled in underground coal mines (rock dust bags, ventilation stopping blocks, and crib blocks). Each study utilized 12 subjects, all of whom had considerable experience working in underground coal mines. Effects of lifting in four postures (standing, stooping under a 1.5 m ceiling, stooping under a 1.2 m ceiling, and kneeling) were investigated together with four lifting conditions (combinations of lifting symmetry and lifting height). The frequency of lifting was set at 4 per minute, and the task duration was 15 minutes. Posture significantly affected the MAWL for the rock dust bag (standing MAWL was 7% greater than restricted postures and kneeling MAWL was 6.4% less than stooped); however, posture interacted with lifting conditions for both of the other materials. Physiological costs were found to be significantly greater in the stooped postures compared to kneeling for all materials. Other contrasts (standing versus restricted postures, stooping under 1.5 m ceiling versus stooping under 1.2 m ceiling) did not exhibit significantly different levels of energy expenditure. Energy expenditure was significantly affected by vertical lifting height; however, the plane of lifting had little influence on metabolic cost. Recommended acceptable workloads for the three materials are 20.0 kg for the rock dust bag, 16.5 kg for the ventilation stopping block, and 14.7 kg for the crib block. These results suggest that miners are often required to lift supplies that are substantially heavier than psychophysically acceptable lifting limits.
Implications of the Proposed Revisions in a Draft of the Revised NIOSH Lifting Guide (1991) for Job Redesign: A Field Study
Authors: Karwowski Waldemar , Brokaw Nina
Published: July 2017

The main objective of this research project was to compare the recommended load limits for lifting tasks derived based on the NIOSH (1981) Lifting Guide and the proposed NIOSH Draft Revisions of (1991). The study involved the following steps: 1) Identification of a total of 15 manual lifting tasks from 8 different jobs performed at the industrial site, with different tasks characteristics in order to cover most of the possible lifting conditions considered under the Draft Revisions to the NIOSH Guide (1991), 2) Description of the lifting tasks variables for the identified jobs, 3) Calculation of the RWL values for the identified jobs per 1991 Lifting Guide, as well as the AL and MPL values according the 1981 Lifting Guide, 4) Comparison of the actual loads lifted (L) with the values of RWL, AL and MPL, and calculation. The results showed that the Draft Guide of 1991 was much more restrictive with respect to defining the lifting acceptable jobs. Under this Guide, 10 out of 15 tasks analyzed in this study (66.7%) were found unacceptable, and required redesigning. For comparison, under the NIOSH (1981) Guide, as many as 8 of 15 (53.3%) of the tasks were found fully acceptable (below the action limit or AL level), while 6 tasks (40%) required application of administrative controls, and only 1 of the 15 tasks analyzed (6.7%) was found unacceptable.
Effects of Gender, Lift Height, Direction, and Load on the Ability to Estimate Weight
Authors: Rice Valerie J. , Sharp Marilyn A. , Williamson Tania L. , Nindl Bradley C.
Published: July 2017

The study evaluated the effects of gender, lift height, direction (lift/lower), and load on the ability to correctly estimate weight handled. Seven women and six men lifted and lowered boxes to and from knuckle, waist, and shoulder heights. Subjects were asked to estimate weights corresponding to 50, 40, 30, and 20% of gender specific lifting strength to 152 cm. The difference between the actual and estimated weight (DIFF) was 100% greater for men than for women (F = 6.27, p = 0.03). When the percent difference was analyzed, there was no significant gender effect. The least accurate estimates occurred when lowering a weight from knuckle height (p < 0.05). The majority of subjects underestimated the weight and men underestimated more frequently than women (Chi2 = 12.57, p = 0.0004). Subjects overestimated the weight more often at higher weights. The results suggest that both men and women tend to underestimate weight, especially when lowering from knuckle height, possibly putting them at risk for injury.
Maf for Males Performing Drilling Tasks
Authors: Vaidyanathan Viswanath , Fernandez Jeffrey E.
Published: July 2017

A laboratory experiment was conducted using the psychophysical approach to determine maximum acceptable frequency (MAF) for a simulated sheet metal drilling task under varying angles of wrist flexion. Fifteen male students served as subjects for this study. The subjects were asked to perform a simulated drilling task in five different wrist flexion postures. Results indicated that MAF was significantly reduced (p<0.001) for deviated wrist postures in the transverse plane. It was noted that there was a 33% decrease in MAF values from 0 degree wrist flexion (neutral posture) to 40 degree wrist flexion. These results imply that industrial guidelines for drilling operations involving wrist flexion must consider the MAPs in order to reduce the risk of cumulative trauma disorders.
Perceived Exertion in Isometric Muscular Contractions Related to Age, Muscle, Force Level and Duration
Authors: Deeb Joseph M. , Drury Colin G.
Published: July 2017

This research was concerned with studying the development and growth of perceived effort of long-term isometric contractions as a function of muscle group (biceps vs quadriceps), of subjects with different age groups (20–29 vs. 50–59 years old) on long-term muscular isometric contractions (5 minutes) at different levels of %MVC (20, 40, 60, 80 and 100 %MVC). An experiment testing 20 subjects each performing 10 conditions (two muscle groups × five levels of %MVC) showed that the older age group reported Significantly higher perceived exertion at higher levels of %MVC and across time. Furthermore, subjects experienced a higher and faster increase in their perceived exertion when the level of %MVC and time increased.
Trunk Muscle Activation While Resisting Asymmetrically Applied Loads in an Axially Rotated Posture
Authors: Lavender Steven A. , Tsuang Yang-Hwei , Andersson Gunnar B.J.
Published: July 2017

The present investigation describes the electromyographic (EMG) response of eight trunk muscles during the application of loads to the torso while subjects maintained a twisted posture. The external moments of 20 and 40 Nm were applied to a harness system as each of the 10 subjects twisted 25 degrees. The applied moment direction was varied in 3 0 degree increments completely around the subjects (0 to 33 0 degrees). Surface EMG was used to monitor the left and right Latissimus Dorsi, Erector Spinae, External Oblique, and Rectus Abdominus. Multivariate and univariate analyses of variance (MANOVA and ANOVA) procedures showed significant main effects for all muscles and a significant moment magnitude by moment direction interaction effect in 6 of the 8 muscles. The greatest muscle activity was observed in the right Erector Spinae and the left External Oblique muscles. The results are also compared with an earlier study in which a similar loading paradigm was used as subject maintained a neutral upright posture.
Comparison of Power Grasp and Three-Jaw Chuck Pinch Static Strength and Endurance between Industrial Workers and College Students: A Pilot Study
Authors: McMullin Dianne L. , Hallbeck M. Susan
Published: July 2017

Due to the ease of obtaining subjects, much ergonomics research utilizes students. However, is it valid to make a hypothesis concerning industrial workers from this student data? To evaluate the validity of such a generalization, ten industrial workers and ten students, five men and five women from each subject sample participated in the study. The functional range of motion for extension and flexion in the wrist and anthropometric measurements of the hand and arm were measured for each subject. In addition, the three-jaw chuck pinch force and endurance and power grasp force and endurance were also measured. The data was analyzed using both paired comparisons and ANOVA tests. Only power grasp force showed a strength difference between students and industrial workers. The students had 82.9% of the grasp force of the industrial workers.
Effects of Full Motion Forearm Supports and a Negative Slope Keyboarding Keyboard Support System on Hand-Wrist Posture While
Authors: Powers James R. , Hedge Alan , Martin Michael G.
Published: July 2017

The effects of full motion forearm supports and a negative slope keyboard support system on hand-wrist posture were tested. No differences in posture were found between normal use of a keyboard and that with full motion forearm supports. Use of the negative slope keyboard support system increased body-to-screen distance and reduced wrist extension so that the wrist was vertically neutral for keyboarding.
Likelihood of Reading Warnings: The Effect of Fonts and Font Sizes
Authors: Braun Curt C. , Silver N. Clayton , Stock Barry R.
Published: July 2017

Legibility of a warning is a major issue in the labeling of various consumer products, and over the counter and prescription drugs. The purpose of the present research was to examine certain variables that are associated with legibility, namely font type, font weight, point size, and point size contrast between the signal word and the main body of the warning. A sample of undergraduate students and elderly people rated 24 Ultra Tide detergent labels for their likelihood to read the warning, the saliency of the warning, and readability of the warning. The results indicated that participants were more likely to read the warning in Helvetica type than in Times or Goudy. Times was more likely to be read than Goudy. Bold type was more likely to be read than Roman type. There was a greater likelihood of reading the warning when the main body was in 10 point size as compared to 8 point size. A 2 point size difference between the signal word and the main body of the warning produced a greater likelihood of reading the warning over a 4 point size difference. One possibility for this result is that the 4 point difference minimizes the importance of the main body of the warning, therefore making only the signal word salient.
Warnings and Expert Opinions An Evaluation Methodology based on Fuzzy Probabilities
Authors: Kreifeldt John G.
Published: July 2017

A number of mandated and voluntary standards and guidelines expressed as good practice have been set out for the design of warnings. However, the question always arises as to whether or not a given warning will accomplish (or would have accomplished) its purpose of preventing injury whether or not it follows such guidelines. The answer to this question must be phrased in probabilities and sometimes only in qualitative form such as “low probability”, “high probability”, “more probable than not”, etc. In order to obtain such answers, experts are often consulted for their opinions. A methodology is presented which can be used as a basis for checking the consistency of the final conclusions or opinions using the concept of “fuzzy probabilities” and conceptually simple computations. The methodology is also of use to the expert in formulating his opinion rationally and deducing its implications clearly. This methodology is presented here in the context of the opined probability of effectiveness of warnings and instructions although it may be used in any context in which the total proposition can be phrased as a set of interrelated sub propositions as is common in reliability theory, decision theory, etc.
Using Transportation Accident Databases in Human Factors Research
Authors: Mayer David L. , Ellingstad Vernon S.
Published: July 2017

Accident databases commonly contain factual information about the time and date of each accident, vehicle characteristics, number of persons killed and injured, and other kinds of factual data. These attributes of the environment and equipment are usually directly represented in databases. In contrast, detailed analysis of accident causes, including human factors information, are frequently not represented because they are much more difficult to obtain and code.

This paper explores the suitability of transportation accident databases for use in human factors research. Given the goal of reducing the number and severity of transportation accidents, it is useful to use accident data as a tool to understand the common causes of accidents. Problems arise, however, because existing databases were typically not created explicitly for research purposes, and coding systems and file structures often omit or obscure useful information. Improved coding schemes and file structures that promote the use of databases for human factors research are discussed. Accident investigation methodologies that can improve the quality of human factors information in databases are also considered. Finally, problems associated with the use of existing databases are noted.
Work Practices and Fatigue in the Long Distance Road Transport Industry in Australia
Authors: Feyer Anne-Marie , Williamson Ann M.
Published: July 2017

A Questionnaire was used to obtain information from 960 long distance truck drivers about the drivers” experience, type of employment and their working conditions, type of driving operation, as well as details of their last trip and their last working week. Operations specifically designed to combat driver fatigue by provision of a relief driver in a team operation did not appear to achieve their intended outcome. The potential benefits of such operations appeared to be outweighed by the greater distances and lack of flexibility that characterised these trips.
Human Factors Influencing Machine-Related High “Cost” Accidents in Industrial Operations
Authors: Brogmus George Erich , Meshkati Najmedin
Published: July 2017

Using the Liberty Mutual Insurance Group Data Base, 13 industrial machine-related accidents reported during 1990 with incurred losses over $200,000 each were analyzed for contributing human factors elements. The results indicate that machine-related high cost accidents in industrial operations have a multitude of human factors-related influences, both on the macro and micro-ergonomic levels.
The Potential Value of a Front-to-Rear-End Collision Warning System Based on Factors of Driver Behavior, Visual Perception and Brake Reaction Time
Authors: McGehee Daniel V. , Dingus Thomas A. , Horowitz Avraham D.
Published: July 2017

The potential value of a front-to-rear-end collision warning system based on factors of driver behavior, visual perception and brake reaction time is examined in this paper.

Twenty-four percent of all motor vehicle crashes involving two or more vehicles are front-to-rear-end collisions. These collisions demonstrate that several driver performance factors are common. The literature indicates that drivers use the relative size and the visual angle of the vehicle ahead when making judgments regarding depth. In addition, drivers often have difficulty gauging velocity differences and depth cues between themselves and the vehicle they are following. Finally, drivers often follow at distances that are closer than brake-reaction time permits for accident avoidance. It is apparent that the comfort level of close following behavior increases over time due to the rarity of consequences. Experience also teaches drivers that the vehicle in front does not suddenly slow down very often.

On the basis of these driver behavior and human performance issues, a front-to-rear-end collision warning system that provides headway/following distance and velocity change information is considered. Based on the driver performance issues, display design recommendations are outlined. The value of such a device may be demonstrated by the added driver safety and situation awareness provided. The long-term goal would ultimately be the reduction of one of the most frequent type of automobile crashes.
Accidents with Consumer Products
Authors: Weegels M.F.
Published: July 2017

This paper deals with the question to what extent various factors, suggested in the literature, can be identified as contributory to the occurrence of accidents with consumer products. Data have been gathered in an on-site investigation of accidents. Contributory factors taken into consideration in the method of data collection include characteristics of the use actions, the product, the situation and the user. The explorative study revealed that the relevance of the various contributory factors is limited. This would imply that the development of general guidelines for the anticipation of accidents in the design of everyday products is seriously hampered.
Method Bias and Concurrent Verbal Protocol in Software Usability Testing
Authors: Wright Richard B. , Converse Sharonlyn A.
Published: July 2017

Concurrent verbal protocols are gaining wide acceptance in software usability testing. In this study, the impact concurrent verbalization has on task performance during a software usability test was investigated. Subjects randomly assigned to two levels of verbalization were asked to complete four tasks of varying difficulty using a disk utility package. Subjects in the verbalization condition were asked to provide an explanation for each step taken to complete a task. Subjects in the control condition were allowed to complete each task silently. Dependent variables were task time, error frequency, and responses to subjective measures of mental workload and ease-of-use. Subjects in the verbalization condition committed fewer errors and consumed less task time than subjects in the silent condition. Further, the mean difference in error frequency and task time between conditions increased with task difficulty. These results were extremely important in revealing a potential method bias in usability tests.
Integrating Microgravity Test Data with a Human Computer Reach Model
Authors: Whitmore Mihriban , Aldridge Ann M. , Morris Randy B. , Pandya Abhilash K. , Wilmington Robert P. , Jensen Dean G. , Maidaxy James C.
Published: July 2017

Future space vehicles such as the Space Station Freedom will be equipped with computers that have direct manipulation capabilities. The human factors challenge is to provide an optimal human-systems interface which will accommodate a wide range of users and tasks in a microgravity environment. A series of experiments have been conducted by the Man-Systems Division at Johnson Space Center to resolve anthropometric issues related to human reach capabilities and limitations impacting workstation design. To facilitate this goal, two approaches, “Performance-based” and “Model-based” analyses, were integrated to investigate the human reach mapped onto the workstation display panels. Microgravity maximum reach sweep data were collected onboard NASA's KC-135 Reduced Gravity Aircraft. A three-dimensional (3-D) interactive graphics system, PLAID, was used to generate anthropometrically correct human computer models. Video tapes recorded during the flights were used to extract information for positioning each human representation in the computer model relative to the workstation. The approach, findings and implications of the evaluations are discussed in the paper.