“NOTE: The material in this paper is extracted from a chapter entitled "Forensic Human Factors Psychology," which the writer developed for a book by Kurke, M. I. and Meyer, R. G. (eds) entitled "Psychology in Product Liability and Personal Injury Litigation." Because of space restrictions, four sections of the chapter had to be omitted. These sections dealt with tools and methods, the CPSC, OSHA, and a description of the features of an adequate safety program. The interested reader is referred to the Kurke-Meyer book for the full text.”
“The present paper described 1) the operation of a software tool for interface prototyping -- RAPID -- that is designed for software designers and human engineering specialists to use in support of design iteration and experimentation and 2) an application of this prototyping tool in the development of consumer products. RAPID simulates the appearance and function of small control panels including commonly-used displays and controls using the Smalltalk-80 computing environment The experience of using the design tool in a product development effort has provided a means of evaluating the success of this approach for supporting the product development cycle and improving the quality of the human-machine interface.”
“In a simulation of industrial quality control inspection, performance was tracked over a period of three months using target conditions which had previously been shown to produce performance decrements with multiple flaws. Feedback on performance was supplied to inspectors at the end of each day's work. Results showed that by the end of the period, multiple fault inspection performance was equal to or slightly better, in both accuracy and latency, than previous data obtained with single fault conditions. This finding raises concerns over previous studies which have attempted to address the issue of the supposed performance decrement associated with increasing the size of the target set.”
“Industrial inspectors are becoming more dependant on the stereoscopic microscope for detecting microminiature defects in electronic components. The present study investigated the effect of magnification on the detection of scratch defects in the etching of printed circuit boards. Ten subjects were tested under 3 levels of magnification (10x, 16x and 30x) with the time for each view adjusted so that the total viewing time remained constant. Results showed a significant increase in inspector sensitivity (d') at the 30x magnification level. Inspector sensitivity in the 10x and 16x conditions was not significantly different. These results suggest that improvements in inspector performance through magnification are possible without increasing inspection time.”
“This paper examines the generalizability of participatory ergonomics to different cultures. Studies using participatory strategies to introduce ergonomic solutions are reviewed across three distinct cultures. The results lead us to believe that these effects are sufficiently robust and not culture or method bound. Four lessons can be learned from these participatory interventions: 1) Interventions should build on local customs; 2) Solutions should be practical and understandable to the participating end-users; 3) Culture should be used as a resource for solving design and cross-cultural problems; and 4) Synergy between the culture and the intervention will enhance the success and magnify problems of the intervention.”
“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.”
“The importance of recognizing human factors in technology transfer to Newly Industrializing Countries and identifying the increase in complexity of these factors as the human aspect crosses cultural, ethnic and national boundaries is becoming more evident. These considerations are proving to be major determining factors of the success of the technology transfer projects. This paper cites examples and discusses such differences in anthropometrics, physiological aspects, perceptual and cognitive characteristics, and the managerial considerations of work attitudes, training, and translation. These differences need to be identified not only abroad, but also in the U.S., as business with foreign nationals done in the U.S. increases. In other words, human factors in technology transfer should not be limited to developing countries, but should also be applied to operations within the U.S., as visiting foreign nationals also need to be trained.”
“The value of information comes when it is used. The information obtained in our behavioral science disciplines needs to be synthesized to better represent a realistic description of the real world. A knowledge center for synthesizing information from various disciplines is proposed. This center would initially deal with Ergonomics/Organizational Design and Management (ODAM) information in the following thrust areas: 1) Building an information base of ergonomic and ODAM information (may be network of present bases); 2) Developing a taxonomy of the topic area; 3) Synthesizing the information; and 4) Gathering the tools that support: a) Obtaining information; and b) Use of the information.”
“The transformation and movement of technical product and/or service information between individuals, between an individual and an organization, between organizations, etc., might be considered a simple definition of technology transfer. It is often assumed that technical, scientific, and engineering functions determine the quality of technology transfer but there are many other controlling factors. The degree with which the data transferred is mission directed, needed, useful, timely, applicable, and practical for both the sender and receiver has an equally important effect on technology transfer. Individual, organizational, administrative, and management functions have a major role in determining whether these additional issues of technology transfer are met. It is imperative that both technical and support portions of an organization continually examine their effectiveness to meet changing technical objectives of the total organization, and re-structure as needed to meet those objectives to ensure the highest quality and quantity transfer of technological information.”
“Extensive research has been conducted in Western Developed Countries on office ergonomics. The results of this research are presently being assimilated and integrated in Western offices. Concurrently there has been a movement to shift data entry operations to Industrially Developing Countries (IDC). The purpose of this paper is three-fold: 1) To stimulate consciousness among Human Factor professionals that VDT data entry work is being introduced into the developing countries by Western, primarily American, Multinational Corporations (MNC). 2) To explore methodology for applying established ergonomic principals to data entry tasks in IDC. 3) To propose a system model that addresses the unique ergonomic factors of data entry work being performed in IDC.”
“This panel session is intended to be responsive to continued, high-level attention given by the U.S. Army to its MANPRINT (Manpower and Personnel Integration) initiative and to the continued, if not increasing, interest expressed by the human factors community in MANPRINT efforts. LTC William O. Blackwood from the U.S. Army MANPRINT Policy Office will precede the panelists' presentations with a brief MANPRINT overview. MANPRINT interests will then be discussed by panelists representing four perspectives along two dimensions as represented in Figure 1 [to be found in the text].”
“Human factors practitioners are continuously running into inadequate or missing data. This situation prevents or impedes the resolving of design dilemmas at hand. Why is this so? Is it because there are not enough researchers working in the empirical community? Are the empiricists not generating enough data? Perhaps the data that are being compiled are unusable. Is it because the data are redundant? Is it because the data are incompatible with other data sets? Are the current data sets too specific, i.e., ungeneralizable to broad applications? Or are the data that are available invalid, i.e. generated improperly? Are there any avenues that human factors specialists can pursue which would resolve this problem? Are there any policies or practices which could be developed which, if followed, would ensure more effective and usable data in the future? Is there any interest among Human Factors Society members to advocate any of the suggested activities? If so, how should this interest be best utilized? The panel will be represented by members from the practitioning community, the research community, and the academic community. The panel will be comprised of members of the Human Factors Society who will bring with them over a century of accumulated experience and thousands of published pages on human factors topics.”
“An experiment is reported that was conducted to examine the possible value of high-order consistency in skill development. Subjects made judgments about ordinal properties of stimuli. The presence or absence of consistency was defined by the type of decision -- consistent or varied decisions. In both decision conditions the stimuli were inconsistent at the individual stimulus level; however, subjects making consistent decisions concerning the stimuli could make use of consistent relationships among the stimuli. Subjects in the consistent decision were faster and more accurate at identifying target stimuli when compared with the inconsistent decision subjects. In addition to the quantitative differences, subjects receiving consistent decision training were qualitatively different in performance when compared to the inconsistent decision group. The pattern of results from the present experiment is quite consistent with previous memory/visual search investigations. The experiment supports the suggestion that local level (or stimulus based) consistency is not necessary for automatic process development if task relevant high-order (or global) consistency can be identified and used by the trainees.”
“Perceptual learning is required in a number of different contexts. Certain paradigms have been found to speed this learning, others to slow if not altogether inhibit it. The objectives of this study are twofold. First, an experimental test is described of an alternative explanation or model of the finding that perceptual learning is facilitated in consistent mapping tasks, but not in varied mapping ones (Schneider and Shiffrin, 1977). Second, it is shown how the model can be used to select from a set of equally acceptable graphical or symbolic representations of an object that representation which minimizes the time it takes to find the object in a visual search task.”
“This study examined performance in a consistent mapping visual search task in which subjects were required to make discriminations within the disjoint, target, and distractor sets as well as between the sets. The within set discrimination was variably mapped across blocks of trials. The results show strong practice effects consistent with the development of automatic processes.”
“Two rating scale techniques employing an absolute magnitude estimation method, were compared to a relative judgement method for assessing subjective workload. One of the absolute estimation techniques used was an unidimensional overall workload scale and the other was the multidimensional NASA-Task Load Index technique. Thomas Saaty's Analytic Hierarchy Process was the unidimensional relative judgement method used. These techniques were used to assess the subjective workload of various of single- and dual-tracking conditions. The validity of the techniques was defined as their ability to detect the same phenomena observed in the tracking performance. Reliability was assessed by calculating test-retest correlations. Within the context of the experiment, the Saaty Analytic Hierarchy Process was found to be superior in validity and reliability. These findings suggest that the relative judgement method would be an effective addition to the currently available subjective workload assessment techniques.”
“Eighty-one male subjects performed four information processing tasks and six dual task combinations, and completed a battery of psychometric ability tests selected to define three first-order factors and a second-order general ability factor. Confirmatory maximum likelihood factor analyses of the performance data provided no support for a general time-sharing factor, but a model with factors corresponding to the four single tasks provided a good fit to the data. The Grammatical Reasoning factor was highly correlated with the Verbal and second-order General Ability factors, suggesting that this task may be a good single index of total attentional resources.”
“The head-up displays (HUD's) of today's fighter aircraft present numerous symbology formats to the pilot which are essential for successful performance of a variety of flight tasks from navigation to weapons delivery. One common element in all of these formats is the pitch ladder, designed to provide the pilot with aircraft attitude even in the absence of external visual cues. Unlike the head down attitude director indicator (ADI), the HUD pitch ladder's intent is to aid the pilot in recovering from an unusual attitude while staying head-up. The purpose of this research was to compare the relative effectiveness of two changes to current pitch ladder symbology designed to enhance the pilot's ability to recover from unusual attitudes -- the use of angled pitch bars versus standard straight pitch bars and multicolor versus the standard monochromatic symbology. The results showed that, in extreme unusual attitudes, the use of both the angled pitch bars and color contributed to better flight performance. In the non-extreme attitudes however, where the horizon line is always visible, the standard symbology was sufficient for recovery.”
“Identifying the underlying decision criteria used by operators to classify system state, and revealing the way in which that information is internally represented in one of the challenges facing designers of control systems. This paper describes the use of multidimensional scaling (MDS) to probe the structure and composition of the internal conceptual models used by operators to identify system state. Specifically, the issue of individual differences in mental model is addressed, as well as the impact of these differences on individual performance in a classification task. Twenty subjects were trained as operators to classify instances of system data into one of four system state categories. After training, subjects were asked to rate the similarity between instances of system state. Results showed that the dominant dimensions used by an individual are related to his/her performance on the classification task.”
“Use of pictorial displays was explored as one solution to the complexity of modern aircraft and missions. A simulator crew-in-the-loop study was conducted to evaluate the utility and crew acceptance of pictorial formal displays for two-seat fighter-attack aircraft, to determine whether utility and crew acceptance were affected by application of color, and to recommend format changes based on the results. Pictorial formats were developed in both color and monochrome for the Head-Up Display and tactical, situation, and system status displays. Sixteen operational two-man aircrews learned the formats and flew them in mission simulation. Opinion, workload, and performance data were collected. The crews clearly supported the concept of pictorial formats, preferred the color version, and provided critiques of specific formats.”
“During the last 13 years the investigation of crew alerting during non-normal situations has progressed from the study of a single system, altitude monitoring, to a consideration of the total system. The result of this progression is that a highly self-contained system concept has been defined that will facilitate an effective crew response to both normal and non-normal situations. The concept system is intended to not only monitor aircraft systems and flight operations, but also provide improved guidance and status information. The form the information takes will ultimately affect the timeliness of information perception, processing, and crew performance. This paper describes three studies conducted to assess the relative effectiveness of selected display formats in communicating time-critical information to commercial airline pilots. A part-task simulation was used to collect response time and number of errors. Format type, format complexity, and format symbology were varied in this evaluation. Results showed that response to symbolic formats without alphanumerics was faster and more accurate than to symbolic formats with alphanumerics or alphanumeric only formats. These results were incorporated into a full mission aircraft simulator for evaluating the effectiveness of the system concept and eventual incorporation into FAA guidelines for future commercial aircraft.”
“The advent of increasingly powerful microcomputers, coupled with the development of small, feature-packed expert systems now makes it cost effective to provide workers with relatively inexpensive desktop expert systems. In order to evaluate the value of such systems as work aids for human factors engineers, we developed a small demonstration system using a commercially available expert system development tool, NEXPERT (tm), released in 1985 by Neuron Data, Inc. of Palo Alto, CA. We selected a candidate problem area based on four criteria: 1) the problem domain had to be small enough to be covered comprehensively by a relatively small knowledge base; 2) the problem domain had to be potentially useful to video display terminal (VDT) screen designers; 3) appropriate information had to be readily available in human factors guidelines, published reports, and journal articles; and 4) the problem should provide the opportunity to exercise as many of the features of NEXPERT as possible. The topic area we selected was "video display screen color". Our goal was to produce a job performance aid (JPA) that non-human factors VDT screen designers could use to select appropriate colors for screen features. Because the system users typically have little or no formal training in human factors, the JPA has to supply color recommendations in the form of clearly stated requirements, but with the decision rationale and additional references also immediately available for users wanting more information. Using the expert system shell provided by NEXPERT, we constructed a knowledge base containing more than one hundred IF ..., THEN ... rules representing knowledge gained from a detailed literature review. We initially validated our expert system by posing a wide variety of hypothetical design problems and assessing its conclusions against our expectations. Based on our work so far, we have concluded that small expert systems can be useful in providing human factors expertise to system designers. We believe that increasing use of expert systems may soon lead to changes in the typical current scientific publication format to include knowledge base rules provided by the author(s).”
“The goal of this research was to provide a set of criteria for the effective use of color on the IBM 5153 Color Display. Available guidelines provide direction but not the detail required for application programmers. This study examined character legibility and subjective preference for color combinations in text in an application program. The effectiveness of color combinations was defined as a joint function of response time and subjective rating. The graphs of foreground/background color relationships show the observers' performance as a function of their preference. The results indicated the flexibility of black or blue backgrounds. The findings are discussed with respect to principles of human perception.”
“Individuals are routinely subjected to dry environments. These conditions may result from geographic areas, the heating of indoor spaces, or specialized settings (e.g. commercial aircraft cabins). This paper examines the affect of low humidity from two perspectives: comfort and health. Results indicate that the dry-bulb temperature is only 7.8 times more important than relative humidity (rh) in determining the subjective thermal response, and that rh has a greater role in determining how men feel than how women feel. Additionally, it was shown that a perceivable level of annoyance is experienced by both wearers and nonwearers of soft contact lenses at or below 30% rh, and this effect becomes most pronounced after four hours. Other findings indicated that the perception of varying odor intensity levels (e.g., cigarette smoke) is higher in dry environments; several studies are also reported showing the health related benefits of humidification.”
“It has been difficult to differentiate statistically among lighting conditions. A questionnaire, using 12 positive adjectives, was developed which was sensitive enough to show differences among lighting variables. Twenty subjects each spent 20 minutes in each of 12 conditions. The 12 conditions were all combinations of screen glare (high and low), ambient light source (kiosk and kiosk + ceiling), and document luminance (25, 160 and 320”
“This paper investigatest the optimal illumination levels for offices equipped with visual display units (VDUs). Twenty-four paid subjects keyed in typical word processing data for 6 min per condition. General illumination was provided by a mixture of indirect and direct lighting sources. This illumination was held at 350 lux at the workstation. The experimental variables for the 6 conditions were: (1) two illuminations of the room wall and (2) three illumination levels in the area directly ahead of the operator. When VDU workstations are illuminated at 350 lux to eliminate glare, operators prefer an intermediate illumination level (800 lux) in the office space to their front over 415 lux or 1170 lux. Operators also preferred increased brightness contrast on the wall. Design should consider not only the workstation itself but also the surrounding.”
“The forensic area of practice for human factors engineers has brought into sharp focus the differences of opinion which exist regarding the effectiveness of warnings in bringing about safe behavior on the part of the user of a product. This paper addresses the major issues which the authors believe must be researched further to provide the definitive answers needed regarding the effectiveness of warnings in a variety of possible applications. A review of the literature will demonstrate that there are few studies of warning effectiveness per se, while there are many studies that address such issues as the need for warnings and presumed criteria for preparing effective warnings. It is suggested that further research is needed which addresses warning effectiveness in actual use situations, and in turn identifies the importance of such variables as stimulus energy level, information overload, risk perception, cost of compliance and the interaction of warnings, instructions and training.”
“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.”
“Ten ergonomic office chairs, chosen from a sample of eighty-four, were evaluated in an ergonomic field study. Twenty office employees used each of the chairs for one day. The chairs were evaluated using four different methods: a chair feature evaluation checklist, a ranking procedure, general comfort and body part discomfort ratings. The first two methods produced positive results, including significant differences between the chairs. The chair users generally had difficulties in perceiving and expressing their comfort and discomfort associated with the latter two methods. The study identified several distinct features related to chair comfort, including the design of the seat pan, back rest, arm rests and ease of adjustability.”
“In the use of control panels for the automotive industry, consistency and usability are of major importance. General qualitative guidelines exist for the designer, but there is currently a lack of quantitative human factors data for control panel designs. A state of the art design tool which provides the designer with ergonomic usability guidelines and structure is needed. As part of the current research, a computer-based tool which provides a quantitative analysis of the ergonomic quality of a control panel layout has been created. This tool is a tailored Auto-CAD program for the IBM PC which provides features to encourage consistency and structure in the design of control panel layouts. Extending the work by Tullis (1983) on alphanumeric display metrics, four graphical metrics for the overall and functional design levels are included as part of the design tool. These metrics are: 1) Overall Density -- rate of free space to occupied space, 2) Local Density -- how closely placed the design entities are to each other, 3) Layout Complexity -- position irregularity of functional areas, and 4) Display Grouping -- number of functions and number of controls and displays. In this effort, the design metrics and the design tool have been developed.”
“This study is part of an on-going series of studies that relate to Alpine or Downhill Ski Boot Design. In current Alpine skiing, the ski boot is an integral part of the ski boot-binding system. One of the roles of the ski boot is to protect the ankle from excessive dorsiflexion during forward falls, as the ski boot is levered out of the heel binding. A boot designer needs to know what the ranges of dorsiflexion are for human ankles so that the allowable forward flex built into the ski boot will not exceed some specified level. That specified level should be such that a large part of the population will not exceed a safe level of dorsiflexion. The stiffening of the ankle by voluntary contraction of the muscles that control the ankle joint cannot be relied upon since the reaction time to contract the muscles will be greater than the time available to the skier under many circumstances. This study looks at the maximum voluntary dorsiflexion of a group of people (n=64) similar to a skiing population. The anatomical and biomechanical posture of the subjects was intended to represent typical skiing situations; therefore, the subjects were measured in a weight bearing, flexed knee, upright posture. The age, gender, height, weight and skiing experience of the subjects was recorded as independent variables. The maximum voluntary dorsiflexion of the ankle was the dependent variable. Ten subjects were measured while the knee was kept in a straight or extended posture. The analysis indicates that there is no statistically significant relationship between dorsiflexion and any of the independent variables. The mean dorsiflexion was 42.7 degrees, the 5th% value was 28.5 and the 95th% was 56.7 degrees. The straight knee posture reduces the effective dorsiflexion by 8.5 degrees. Current standards permit as much as 40 to 45 degrees dorsiflexion. The implications are that current standards are excessive, a reasonable limit would be something under 30 degrees. Such a limit, or less, is consistent with the maximum dorsiflexion found in most current ski boots.”
“A research and development project is under way to specify, design, construct, and evaluate a user interface system to meet the unique requirements of a delivery vehicle for a knowledge-based system applied to gas turbine electronics maintenance and trouble-shooting. The prototype user interface is a portable device with text display, video and overlay graphics display, voice recognition and speech production, special-function keypad, and printer. A modular software structure based on a serial communications protocol between user interface device and expert system host computer provides flexibility, expandablity, and a simple, effective user interface dialog. A human factors field evaluation is being conducted to assess aspects of system usability: device hardware, system operability, information presentation effectiveness, and user training.”
“Impressive reductions in injury rate were achieved in a cooperative program that included industrial human factors. The other players in the program include the medical department nurses, the safety engineers, production engineers, supervisors and production workers. The explanation offered for the program's apparent success is that responsibility and accountability for industrial human factors improvement is distributed among the various departments involved.”
“The paper discusses a methodology to allocate functions to people and/or machines based upon the requirements of the tasks to be performed and the capabilities of each system. Although function allocation has been addressed within the human factors community for many years, the approach discussed offers two primary advances in the context of manufacturing and assembly systems. First, the state-of-the-art in automated systems, robotics, flexible manufacturing systems, methods analysis and human factors are integrated into a multi-disciplinary approach. Second, the methodology will provide manufacturing engineers with an easily understood procedure for assigning tasks to the appropriate system on cost/capability basis.”
“This presentation discusses the approach to and results of a major program to redesign the purchasing system of a large corporation. The discussion summarizes the methodology used to evaluate the existing system and to recommend a work environment for the new system.”
“This paper addresses the changing role of the human factors professional in the design of integrated computer systems for telecommunications engineering. Specifically, with the advent of such software, the human-computer interface is at times replaced by a computer-computer interface. With humans removed from the direct processing function, should human factors designers be removed from the design function as well? Our experience has shown that there is in fact a continuing need for our expertise, as long as humans remain in the process in any role. With the changing roles of our users, however, the focus of our efforts should change. The quality and utility of an automated computer system will be optimized by the early and persistent involvement of human factors designers in task analysis, user identification, function allocation, system design, user education, and quality assurance.”
“A measurement program was designed to assess benefits derived from the pilot implementation of an office automation system at the Westinghouse Nuclear Fuel Division. The system featured IBM PROFS, graphics software, and computation software hosted on an IBM mainframe computer. Managers, engineers, and secretaries were included in the test group (N = 40) and control group (N = 30) to ensure that each group accurately represented NFD. Measurement tools included an attitude survey and document evaluation logs, which were distributed to the test and control groups before and after the system was installed. In addition, a user evaluation survey was distributed to only the test group after they had had access to the system for five months. Although usage of the system was moderate, benefits were identified for activities associated with document preparation and distribution, message sending, calendar use, and computations. These benefits encouraged management to proceed with full scale implementation of the office automation system.”
“This paper examines and discusses the implications of a macroergonomic perspective for assimilating advanced manufacturing technological innovations into an organization's human infrastructure. A framework for integrating sociotechnical systems and advanced manufacturing technology design is presented which identifies first-and second-order effects of the new technology on the human infrastructure. The Human Infrastructure Impact Statement (HISS) operationalizes these concepts into a systematic assessment tool. This paper ends with a brief list of some of the pertinent macroergonomic decisions that a manager and macroergonomist must consider in implementing and designing Advance Manufacturing Technologies.”
“The purpose of this research was to evaluate differences in processing ability between integral and separable representations of process control data under conditions of time constraints. Subjects were trained as "operators" to identify system states and subsequently participated in time constrained (100%,”
“This paper describes Electric Power Research Institute (EPRI) sponsored case studies of two nuclear power plants that automated their maintenance management system in an effort to improve maintenance processing. These case studies evaluated the impact of an automated maintenance management system (AMMS) on the organizational interfaces and information requirements of a variety of system users. The goal of the project was to provide guidance to the electric power industry in maintenance management system design. A product of the investigation was a set of guidelines for use by utilities in conducting a front-end functional requirements analysis to help define major information requirements and organizational and data file interfaces.”
“This paper presents a human centered computer simulation model for the ingress, egress, and bi-directional processing of personnel through the contamination control area (CCA) of a collective protection system. Collective protection systems are being developed by the Armed Forces to provide an area where individuals may rest, sleep, and eat without the need to wear individual protective clothing in a chemical warfare environment. Individuals enter these collective protection systems through a contamination control area by following a set of procedures for decontamination and removal of their protective clothing. The purpose for developing this computer model was to provide a means for detailed analysis and design of a CCA prior to actual prototype or operational test and evaluation. It can be used to analyze alternative operational scenarios for systems that have already been constructed. The program structure was developed as part of an iterative task analytical approach which was used to design a prototype collective protection system. The model generates a visual representation of the process on the computer monitor. It includes distributions of process times and arrival intervals. The model can be used to determine the effects of variations in process times, variations in process time distributions, training effects, and alternative hardware configurations. This model could be modified to analyze or design almost any process that is comprised of a series of sequential tasks or operations.”
“Human Engineering methods were employed to critique a SDI simulation software package. The areas of human performance measures, subjective responses, number of options to view, commonality of different sections, and user support functions were evaluated. This was for the intent of creating a program that was "user-friendly" and would require a minimal amount of training time. A naive user was provided a checklist and asked to score the input and output interface modules while creating a scenario. Written text followed the checklists which included detailed examples for increasing the efficiency in the designated deficient areas. This let to incorporating changes for a more effective program, reducing cost and time.”
“Jensen (1985) described a method for presenting data in a three-dimensional format that would typically be presented in a scatterplot. The present paper compared these two methods of presenting data. Twenty-four subjects, all of whom had completed an undergraduate class in statistics, were presented with sets of graphs depicting bi-variate data that varied in correlation from about 0.0 to about .99. Three different data groups were depicted as both scatterplots and as three-dimensional graphs. Subjects rank ordered these sets of graphs on the basis of the degree of relationship present. For each set of graphs the order the subject chose was compared with the known order using Spearman's rho. In the early trials, performance was better with the scatterplots, but by the last trial there was no difference between presentation methods for two out of the three data groups presented. The implications and limitations of these data are discussed.”
“This paper describes the 4th-generation model of the Human Operator Simulator (HOS-IV) as implemented on an IBM PC AT microcomputer. HOS is a general purpose simulation tool for modeling the cognitive, perceptual, and motor activities of an operator who is performing a set of tasks during the course of a mission. HOS provides the capability to model the hardware system and the external environment which impact operator workload and system performance. Discussed are the new features of HOS-IV including the user-oriented interface, knowledge representation scheme, and enhanced modeling capabilities.”
“A signal detection method for evaluating different display codes and formats is described. The method allows one to determine how an observer aggregates information from multiple element displays. The method can be used to assess the relative importance of specific spatial or sequential elements of the display. The efficacy of different formats and arrangements thus can be compared. The paper describes the theoretical basis for the method and briefly summarizes data from several types of visual and auditory displays.”
“Contrast sensitivity (CS) has been reported (Ginsburg et al., 1983) to be strongly related to pilots' aircraft detection performance; however, examination of their results shows a lack of consistency for the CS at any particular spatial frequency to correlate with detection, even for days with similar visibility conditions. To further investigate this relationship, sixty-seven (67) USAF pilots were divided among 8 groups, individually isolated in a bus near the end of a runway on separate days, and detected a T-38 jet aircraft during about 8 landings. CS was measured using the criterion-free two-alternative, temporal forced-choice (2 AFC) technique on the Optronix and with the Vistech VCTS 6500 chart. Visual acuity was assessed at three contrast”
“A class of undergraduate students were screened for their visual acuity and contrast sensitivity on Ginsburg's charts. The subjects obtaining the highest and lowest contrast sensitivity scores were further tested on their complex target detection time. The complex targets consisted of a tank or a human form against a background of a mountainous terrain. The main finding was that target detection time for the high contrast sensitivity subjects was less than half of that of the low contrast sensitivity subjects. Differences in visual acuity between the two groups did not explain the differences in reaction time.”
“Performance on a signal detection task was explainable by differences between the two dimensional Fourier transforms of the background and target stimuli. A signal detection experiment by Marshak and Osarczuk (1984) used target and background stimuli designed to systematically differ in spatial frequency and orientation. They found that the hypothesized Fourier differences increased sensitively and decreased decision time. The present paper reports the Fourier analysis of those stimuli which verify and quantify the stimulus manipulation. Multiple regressions were computed using differences in frequency and orientation to explain performance. The results were that 83 percent of d-prime and 74 percent of the decision time variance could be explained by the Fourier differences. These findings indicate that fourier descriptions of symbols may be used to predict their effectiveness in work station environments.”
“In this study, 24 subjects with 20/20 correctible vision participated in a 3 x 3 x 2 visual estimation experiment. The stimulus was a dot or "ball" bouncing clockwise around a 12° visual angle square according to laws of ideal physics. At the end of the first collision, the ball disappeared, and subjects were then required to estimate where on each wall the ball would subsequently impact. The ball was presented at speeds of 3.5°, 6.7°, 10.0° visual angle/sec. Results indicated that there was a linear relationship in the times required to estimate the positions of the ball after 1, 2, and 3 bounces; however, the positional accuracy deteriorated rapidly after 3 bounces and about 8 seconds. Results also suggested that the speed at which the moving stimulus is observed also influences the speed at which one later imagines the moving object. We believe there is a "default" speed at which subjects optimally prefer to imagine moving objects, and that speed is around 5° to 8° of visual angle/sec. We suggest that simple motion presented on CRT displays might be accurately projected ahead by the subject when it is presented at this default speed.”
“Using a within-subjects design, performance on a continuous cursor control task was measured in three conditions: no gloves, flight gloves, and a combination of three gloves worn simultaneously for chemical, biological, or radiological (CBR) protection. Twelve subjects used their left ring finger on a two-axis force controller to move a cursor on a CRT. After centering it over one of eight possible targets, they depressed the controller to designate the target and end a trial. Time to acquire the target and accuracy in centering the cursor over the target were recorded. Subjects had faster acquisition times in the two glove conditions with no increase in errors, although only the difference between the CBR gloves and no-gloves was statistically significant. My explanation for these findings is that the thickness of the gloves may have improved the fit of the fingertip in the force controller, which was concave, and also prevented the finger from slipping by increasing the coefficient of friction between the finger and the controller.”
“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 when 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.”
“Dual axis compensatory tracking was investigated as a function of whether error displays were integrated or separated, whether axis controls were integrated into one stick or remained separate, and whether the control dynamics on the two axes were the same or different. Tracking error increased and control activity decreased as a function of the summed difficulty of the two control dynamics. Integrated displays and integrated controls both led to increased confusions between tracking axes although error was unaffected. Importantly, performance was also affected by whether the integrality of displays matched that of controls. These results suggest that dual axis tracking is subject to independent effects of resource competition, confusions, and Wickens' (1986b) compatibility of proximity principle.”
“Applications of artificial intelligence (AI) in the cockpit require a deeper understanding of the cognitive processes of the pilot. This paper describes ongoing research concerned with developing cognitive models of pilot behavior that can support the development of expert systems and machine reasoning within the cockpit. An experiment is reported where the behavior of pilots within a flight simulator is observed. Verbal instructions given by the controlling pilot in a "division of labor" task are used to identify salient features of pilot cognitive models of the task. The results of this experiment are interpreted in terms of their implications for the development of future expert systems within the cockpit. Continued research on the cognitive models used by pilots should permit the development of a knowledge base that will assist display design, training programs, and research on mental workload within the cockpit.”
“This paper presents a comparison of experimental results with predictions obtained from Tullis' (1984) model of search times for tabular displays. Three levels of information density for displays with and without highlighting were used in a series of experiments. The highlighting of information was done by adding graphic boundaries (lines). Two levels of highlighting were used. A question-answer type of visual search was performed for two different tasks. The search time results are discussed and a method for utilizing Tullis' model for highlighted displays is suggested.”
“Two experiments investigated the effect of layout complexity for performance at varying levels of practice on four types of information extraction tasks. Layout complexity is defined as the number of unique horizontal and vertical starting positions of items in the display (Tullis, 1984). In the first study, layout complexity was manipulated by either left-justifying or not left-justifying text. In the second study, subject viewed a third experimental screen that displayed the starting positions of items in a completely unpredictable pattern. Moderate violations of the typical guideline recommendation that alphanumeric data be left-justified did not increase user search time across all four tasks in either the first or second study. Furthermore, severe violations of the recommendation did not increase user search time for three tasks (find label, scan data, and compare label). However, when subjects compared multiple data values, the random format did increase user search time. Though performance using the three experimental screens was comparable across the four tasks with only one exception, subjective ratings demonstrated differences between the three formats.”
“The goal of information layout is to physically display information to reinforce the underlying structure of the information. In this paper, I describe an axiomatic model of information layout. The model has three levels: (1) a device-independent representation for structured information, (2) set of axioms (or rules) relating information structure with display attributes, (3) a set of device dependent display attributes used to distinguish differences and show similarities in information structure. The model infers, using logical deductions from its axioms, how display attributes should be used to show the structure of information. A prototype software system exists that allows interactive design and evaluation of screen layouts. Future research is planned to develop an expert system to aid in the automatic design of layouts, and to refine the prototype into a usable system.”
“The purpose of this panel session was to expose participants to the many different evolving roles of human factors engineering in today's industries. Discussants were senior human factors professionals representing computer, government, military, automotive, and commercial industries. Successes and challenges for the human factors profession were identified in each type of industry. Panel discussions focused around the functional roles of human factors within organizations and identifying critical skills necessary for the human factors practitioners to be successful. A synopsis of the views presented during the panel discussions is presented below.”
“This paper has, as its primary objective, the provision of Guidelines for product designers to assist in safe design of consumer products. Presentation of the Guidelines is based on a Human Factors Perspective of consumer behavior in the reasonable and foreseeable use and mis-use of consumer products. The Guidelines for Safe Consumer Product Design included in this paper emphasize the valuable source of Human Factors available to Designers. The paper concludes that safe product design can be planned and designed into products that will reduce the risk of injury, or even death, in product use.”
“Of primary concern to the Army is the compliance of crew workstations to MANPRINT so as to enhance operator comfort and safety in performance of the specified tasks. This paper discusses the methodology and design tools utilized to provide Crew Seats for the Army Tank -- Turreted Air Defense Weapon System. In particular, the use of the Cad System -- Ideas for generating anthropometric models for the 5th percentile male lightly clothed and the 95th percentile male in arctic clothing from MIL-HDBK-759A and the design constraints on MIL-STD-1472C will be reviewed. Potential environmental factors affecting safety and human performance, potential areas of concern regarding entry and egress, potential areas of concern regarding workspace, and the Turreted Weapon System seat requirements will be discussed.”
“During the first eight months of 1987, the author had the opportunity to visit Sweden and Norway. Since Sweden is noted as a leader with respect to occupational safety and health practices, and is also well know for its innovations in the utilization of technology, the author decided to spend some time studying safety issues and answers with regard to process control. Though the work is ongoing at the time of this report, this article contains a summary of the material collected and the observations made, to date. It should not be considered as a technical paper, but as a report of the current activities in Sweden. Individuals interested in more information about the projects discussed should contact the author.”
“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.”
“This study explored an area of Army training performance measurement and assessment (PMA) which has apparently not been examined. It provides an understanding about Army training PMA requirements and uses, and reveals a number of PMA issues which should be more closely examined in the future. The methodology adapted for the study combined elements of Policy Capturing Analysis with elements of Policy Implications Analysis and the Delphi Technique.”
“The purpose of this paper, Determining Training Requirements for Maintenance Personnel, was to conclude a finished generic task analysis for mechanical maintenance personnel. This paper will provide the necessary background information to enable a group to set up a task analysis to make available the information to analyze the training requirements for mechanical maintenance personnel. Determining training requirements for different job positions within an industry that has maintenance personnel is a situation tackled by training departments on a daily basis. The bottom line is efficient and cost effective learning.”
“This study evaluated current training methodologies, particularly Instructional Systems Development (ISD), and recent developments in cognitive science to determine how training procedures should be modified to support training for tasks which require complex cognitive skills. We content that ISD is still viable if procedures are developed for the training of cognitive skills. An important component of ISD which needs to be modified to support training of cognitive skills is the task analysis. We discuss the need for integrating efficient and cost-effective cognitive task analysis methodologies with traditional analysis methods.”
“Farnsworth-Munsell 100-Hue test (FM-100) error scores were compared for two illuminating conditions. The first illuminant was a simulation of CIE standard illuminant C, the recommended illuminant for the FM-100, and the second illuminant was a commonly used fluorescent. An evaluation of some common error patterns was also performed.”
“Visual search and decision making performance together with subjective fatigue were investigated over a four hour time block as a function of display foreground and background chromaticity, using colors matched for equivalent brightness. Although some small differences in performance related to chromaticity were observed, these were not exacerbated over time. On the basis of the performance data obtained and the subjective reports, there would appear to be no support obtained for the general recommendation to avoid the use of red and blue stimuli either alone or in combination in CRT displays.”
“Experiments were performed to evaluate several methods for generating colors having specific CIE chromaticity coordinates and luminances on a CRT. The methods' accuracies are characterized and avenues for improvement are suggested.”
“A description of a novel and very speculative approach to new research directions for human vision with application to robotic vision is described. The goal of the approach is to propose a plausible, implementable, spatial perception model for human vision and apply this model to a stereo robot vision system. The model is based on computer algorithms variously called "Multidimensional Scaling", well known is psychology and sociology but relatively unknown in engineering. These algorithms can reconstruct a spatially accurate model to a high level of metric precision of a "configuration of points" from low quality, error prone non-metric data about the configuration. ALSCAL -- a general purpose computer package adaptable for this purpose is being presently evaluated. This is a departure from typical engineering approaches which are directed toward gathering a low volume of highly precise referenced data about the positions of selected points in the visual scene and substitutes instead an approach of gathering a high volume of very low precision relative data about the interpoint spacings. It would seem that the latter approach is the one actually used by the human vision system. The results are highly encouraging in that the agreement between test configurations of two and three dimensional configurations of points are very faithfully reconstructed from as low as 10 points in a configuration using only rank ordered (i.e. non-metric) information about interpoint spacings. The reconstructions are remarkably robust even under human-like "fuzzy" imprecision in visual measurements.”
“The effects of simulator delays on performance, control behavior, and transfer of training were investigated with a group of subjects who had no experience with fight control tasks. Two types of aircraft were simulated: one with highly responsive dynamics and one with sluggish dynamics. Subjects were assigned to one of four time-delay conditions and to one of the two aircraft types. In the first phase of the experiment, subjects participated in fifty trials (ten trials per day) with a particular time delay (50, 100, 200, or 400 milliseconds). After this "training" phase, all subjects "transferred" to the minimum time-delay condition (50 milliseconds) for another fifty trials. The experimental task required that the subjects maintain constant heading and altitude in the presence of pseudo-random roll-rate and pitch-rate disturbances. There were statistically significant effects of time delay on root-mean-square heading and altitude errors in both the training and transfer phase of the experiment. The effect of delay on transfer of training was greater for the aircraft with sluggish dynamics.”
“The use of computers for cue generation and the safety inherent in simulators permits new "tasks" which are impossible in real flight. We are investigating the potential efficacy of using a particularly striking non-standard task, namely flying at zero-altitude and even below ground. Our hypothesis was that increased experience with optically violent displays during training would improve performance during the testing phase of maintaining low, above ground flight. In the training phase half of the subjects maintained zero altitude while the other half flew as low as possible without crashing. Contrary to our hypothesis the low-trained subjects had a lower standard deviation and mean altitude than the zero-trained subject in testing. Although our hypothesis was not supported, the concept of exploring novel ways of using flight simulators deserves further attention.”
“This paper reports on the development of the On-Board Electronic Warfare Simulator (OBEWS) Ground Support Subsystem (GSS). The discussion will take place on two levels. At the top level, the theme of embedded training and the role that the OBEWS program will have in proving the feasibility of the concept will be discussed. At the second and more detailed level, the intensive human factors engineering effort undertaken in the design/development of the OBEWS GSS man machine interface (MMI) will be presented. A description of the resulting MMI will be included. The paper concludes with recommendations and lessons learned at both levels.”
“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 upper-case. 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.”
“Previous research concerning the pilot's visual scan is descriptive/predictive in nature. This experiment quantitatively demonstrates the information processing aspects of one instrument monitoring technique. The results imply that experienced pilot eye movement patterns reflect workload minimization strategies developed early during flight training.”
“The Apple Macintosh computer has achieved remarkable acceptance by engineering design groups because of its graphics capability, innovative and consistent user interface, and quality software. As one group of human factors engineers using the Macintosh in our daily work, we have developed various tools that help us complete common human factors design tasks more quickly and efficiently than we could otherwise. This paper describes our use of several software applications that we have found to be invaluable in performing our work. The five tools described include: Spreadsheet Task Analysis, a business oriented software tool we have easily adapted to perform detailed human factors task analysis; Typeface Design Software, a selection of Macintosh typefaces that meet human factors standards; Expert System Screen Design Aid, an expert system development tool demonstrating a human factors work aid; Anthropometric Modeling, software-based anthropometric drawings that can be scaled to meet the designer's specific needs; Draw/Paint Programs and Databases, a database of various controls, switches, displays and other hardware components for mockup representations, and a collection of system hardware architecture drawings. We will provide copies of our public domain software to interested individuals within the human factors community as one step toward establishing a Human Factors Macintosh User Group.”
“Reading text from a video display screen is a relatively new modality of human communication. This new technology presents advantages and limitations never considered in the design of typefaces for printed communication. It is well know that people read faster from printed text than from a Cathode Ray Tube (CRT). This paper discussed some of the current work to improve CRT readability. Specifically, we have developed software to be used by a typography designer to design anti-aliased (or "grayscale") CRT typefaces. A new anti-aliased typeface was designed and tested for readability. It was found that readability was significantly improved with this new typeface. This paper describes some of our recent work in this area. The typeface design software and examples of text rendered in a new typeface will be demonstrated on an analog color display.”
“An experimental knowledge-based menu design assistant (MENUDA) was developed to aid the design of menu systems. A conceptual model was first developed to provide a structured construct to organize knowledge of menu system design from the available literature, and to serve as a paradigm for the development of the MENUDA system. The knowledge base and the user interface of the MENUDA system were developed under an interactive microcomputer environment supported by Texas Instruments' Personal Consultant Plus. The current version of the MENUDA system is described in the paper. In addition, the methodology used to derive rules in the MENUDA knowledge-based and the appropriateness of employing a knowledge-based expert system approach to providing use interface design guidelines are discussed.”
“Expert systems must often rely on probabilistic information to solve complex problems. Computer output may consist of more than one possible solution, leaving the final decision to the user. The amount of output and its mode of presentation need to be tailored to the application. In situations requiring fast and accurate decision making, as in military systems, output must be presented in a concise and easy to interpret format. Six presentation variables which could affect alternative selection performance were examined in an experiment: information quantity (4 or 8 numbered alternative values), format (tabular or bar graph), order (ordinal presentation of the alternative numbers or their associated values), bar graph layout (vertical or horizontal bars), bar graph labels (no labeling or labeling of each bar with its associated value), and table type (probability or rank values). The variables were combined into 24 different display formats; each of 24 subjects was tested on all the formats. The task consisted of finding the probability or rank values in the order specified on the top of the CRT screen (high value to low or low to high) and entering the associated alternative numbers on a keyboard. Mean response time and mean errors, over five trials, were the measures of performance on each display format. Results of the analyses indicated that the best display format in terms of the speed and accuracy of selection performance was the 4-alternative vertical bar graph with ordered probabilities and labeled bar values.”
“The effect of music at two levels (60-65 dB and 80-85 dB), vs. no music (silent), on the performance of 40 subjects engaged in a data processing task was studied. It was found that, while the music did not disturb the overall accuracy of the task output, it increased the subjects' speed in data processing and overall productivity. The subjects showed a favorable attitude toward music being introduced at workstations.”
“The main objective of this study was to evaluate the physiological strain imposed on individuals engaged in unloading boxes from a truck. The actual operation was performed in one of the local industries, and was videotaped and timed. This operation served as a basis for a simulation study in the authors' laboratory. Six subjects participated in this study. Since the containers utilized in the actual operation varied greatly, empirical distributions derived from the box sizes and weights handled at that industry were developed based on a sample of 466 boxes. The frequency of handling was 20 times/min. The task duration was 30 min. Heart rate and oxygen consumption were recorded every 5 min for a period of 5 min. The results showed that the task performed can be classified as very heavy work compared to industrial tasks reported in the literature. Physiological responses showed a significant increase over time.”
“A laboratory experiment using 15 male subjects was conducted to document lifting physical work capacity over the frequency range of 2 to 12 lifts per minute and to compare these values to bicycling physical work capacity. Results indicate that bicycling PWC is significantly higher than lifting PWC at the 0.05 level. A variation in lifting PWC as a function of frequency was observed. This could be attributed to lifting technique. Task design should, therefore, not only consider lifting PWC but also the frequency of lift.”
“A laboratory investigation was conducted to determine if synchronization between the work rhythm and the respiratory biorhythm benefits perceptual-motor performance. The effect of work-respiratory (W-R) synchronization on reaction time, error rate, and perceived difficulty was evaluated for a visual choice reaction time task. Interstimulus intervals were chosen to induce a work rhythm. Prior to the experiment, the task was performed in a self-paced mode so that a baseline work rate could be identified for each subject. Each subject (N=22) then performed the task at 3 machine-paced work rhythms; 1) equal to the work rhythm of the baseline work rate, 2) 33% faster than the work rhythm of the baseline work rate, and 3) 33% slower than the work rhythm of the baseline work rate. Each condition consisted to two, 4 min trials separated by a brief rest break. Work rate (in responses per minute) was held constant across conditions through adjustments in task structure. Regression analysis revealed that W-R synchronization was associated with a 1% reduction in error rate and a 15 msec reduction in reaction time. These results suggest that W-R synchronization benefits perceptual-motor performance of repetitive tasks.”
“This study investigates the effect of air velocity and other thermal components on the globe thermometer response. An experiment was conducted in an environmental chamber in order to measure globe temperatures under varying air velocity, relative humidity and air temperature. This study was performed under three different radiant heat levels. It was found that air velocity has a significant effect on the globe thermometer response. This effect is quantified in this study. Neither air temperature nor relative humidity was found to have a significant effect on globe thermometer response.”
“The utility of shared versus isolated operator/display setting was examined in the context of a complex, dynamic, team decisionmaking task. Both alphanumeric and graphic display formats were utilized as well as moderate and fast information presentation rates. Performance scores were significantly higher and subjective workload ratings significantly lower for the graphic display and moderate information rate conditions. No differences were found for shared versus isolated operator-display setting except in the combined "worst case" condition of alphanumeric format and fast information rates, where a slight advantage was found for the shared operator/display setting.”
“Testing word associations, as an extension of simple password entry, may be a practical means of verifying the identify of individual computer users. If each user specifies his/her own cue-response associations, then responses will be easy to remember. It should be easy for legitimate users to respond correctly to word association testing, but virtually impossible for potential intruders. Such testing should also prove easy for a computer to process.”
“The effects of the work environment on performance and QWL was examined in bank proof encoding departments. A multidimensional model was proposed and included environmental factors, people factors, and organizational effectiveness. A large set of variables, measuring all aspects of the model, was reduced via stepwise regression and subjected to a canonical correlation, which yielded two variates. Job design and context were strongly linked to QWL, while job and organizational design, and the physical environment were linked to performance. The necessity of a multidimensional approach was supported by the findings. The model proved useful, but only in a limited sense.”
“Experimental studies conducted by Siegel et al. (1986) revealed that members of decision making groups participated more equally in computer-mediated discussions than in face-to-face discussions. These studies dealt with groups of peers. The purpose of this study was to test whether computer media has an equalizing effect on participation of members of different formal statuses. The experimental design and procedure were similar to the previous study. The main difference was that each group included one high status member and three low status members and all members were of the same gender, in order to avoid effect of diffusion status. The experiment showed that, as expected, the computer media had equalizing effect on participation of group members of different formal status. While in face-to-face discussions, high status members initiated discussion more frequently, spoke more, and were more task-oriented than low status members, in computer-mediated discussions, these measures did not differ significantly for members of different statuses.”
“This paper describes a study that is currently examining distributed problem solving performance in a simulated, dynamic battlefield situation assessment task, using computers as the interface between problem solvers and the simulated environment. There are four objectives of this study. First, identify any possible heuristics or strategies used by the group members in dealing with the problem. Second, observe how distributed situation assessment performance varies with environmentally imposed demands. Third, study human communication in both stressed and unstressed situations. Finally, examine how specific group communication protocols employed under different environmental conditions influence situation assessment performance. Thus, the overall objective of the study is to help identify and characterize human problem solving performance and human-machine performance characteristics that emerge when a computer intermediary resource is made an integral part of a distributed problem solving situation.”
“The primary aim of training is to improve performance. Part-task training may be the more economical method, because full mission training simulators often cost more than the vehicles they simulate. However, the skills learned may not transfer effectively to performance of the complete task. This study investigated the effectiveness of Part-task training on the psychomotor portion of a supervisory control simulation. Twelve subjects were divided into Part-task and Whole-task groups and told to perform the task as quickly as possible. Part-task training was provided with the cursor-control device (a magnetic pen and pad), prior to transition to the Whole-task. Some distinct advantages of the Part-task training were: (1) The Part-task group learned the task faster; (2) The Part-task group's scores and task times continued to improve, while the Whole-task group's did not; and (3) A significant increase in speed of response for the Part-task group and almost no improvement in speed for the Whole-task group.”
“This paper describes factors to be addressed in the evaluation of Total Contract Training (TCT) systems. TCT is increasingly being adopted by the military for the development, implementation, and management of total training systems.”
“To learn how Human Factors Research can help top management create better training, a case study comparison is made of two new training departments, one in a large manufacturing corporation and the other in a state government. Using the findings from participant observer and thermodynamic system techniques, two lists for training improvement are derived: 1. Training Department Manager's Check List and 2. Future Human Factors Research.”
“The objective of this research was to compare scores from modified AFHRL Basic Attributes Tests against speed and proficiency in learning to fly a VTOL simulator. Initially 184 correlational analyses were performed to determine whether there were any significant relationships among various BAT scores and the criterion measures. Based on these results, nine independent variables were selected to enter in stepwise regression equations for four criterion measures. Based on these analyses, the PortaBAT tasks appear to be stable predictors of pilot performance in a VTOL simulator.”
“A study was performed to derive an automation and avionics integration design concept for the NUH-60 Systems Testbed for Avionics Research (STAR) aircraft. The STAR, a one-of-a-kind reconfiguration of the UH-60 Black Hawk helicopter, is being developed by the U.S. Army Avionics Research and Development Activity to provide a flight demonstrator and research vehicle for state-of-the-art cockpit technology. The work was directed toward determining cockpit design preferences associated with single-pilot performances of the Army scout and utility missions. Emphasis was placed on high workload phases of the missions during which eye-out-of-the-cockpit and hands-on-controls performance capabilities would be most crucial. A number of cockpit-based design alternatives in the areas of communication, navigation, aircraft survivability equipment (ASE) operations, subsystem status monitoring, and aircraft performance computation and prediction were systematically derived and proposed.”
“Expert system applications must be carefully selected, designed and integrated into cockpit based on a full understanding of the pilot's tasks, requirements, and capabilities. In this paper, expert systems development issues in the following areas are identified and addressed utilizing processes, methodologies and knowledge from the human factors field: the selection of systems to automate, the elicitation of expert knowledge from pilots, role allocation between the pilot and the system, system design issues, and system evaluation. Considerations of pilot workload, situational awareness, performance and pilot acceptance are considered key to the successful design and implementation of expert systems which will truly enhance the pilot in the performance of his tasks.”
“What is it really like to use a computer reference manual? Where are manuals used? Is it easy to find information? Is the information accurate and complete? Do the format and style support the uses for manuals? Are the materials perceived to be of high quality? These questions were addressed in a field study of the manuals for the MicroVAX II computer system. Results showed consistent needs and opinions across the 10 sites visited. Work environments were typically small and crowded. Manuals were located EVERYWHERE. Customer perceptions depended on how well the manuals helped them perform their jobs. While content and style received high ratings, difficulties with finding information were reported. Users also voiced strong opinions about certain aspects of the physical materials.”
“Because of rapid advances in technology, early considerations of human factors in the design process is imperative. Computer-aided man-models enable man to evaluate the world he designs before it becomes reality. Given a certain environment, can the operator see or touch that which is necessary? Does he fit comfortably in his work station? Using Prime Computer's System for Aiding Man/Machine Interaction Evaluation (SAMMIE), a 3-dimensional human factors modeling tool, a designer can make early decisions thereby relieving time and money constraints produced by late design evaluation conclusions. Technology is advancing the human population into environments with power beyond our control. The aerospace environment, particularly, is rich in hazards. Only by setting limits to the power at hand can man expect to advance further without destroying himself. The computer-aided man-model permits man to experiment with the concept of an environment before committing himself to the perils of the unknown.”
“A three-dimensional (3-D) auditory display can increase the pilot's situational awareness without requiring visual fixation. When visual acquisition is required, the directional sound can give the pilot a more rapid cue to aim the eyes or head. In order to determine the utility and performance of a 3-D auditory display for cockpit applications, a method for generating 3-D auditory cues is required for simulation. Two laboratory systems are described which create, from monaural stimuli, binaural stimuli which can be perceived as localized and stabilized in space, regardless of the listener's head position. Additionally, preliminary results of the localization performance with one approach are presented.”
“Twelve experienced tactical crew members served as subjects in a study which compared three synonymous sets of tactical contact symbols under conditions of color/monochrome and high/low density. Time and accuracy data of responses to stimulus displays were collected and analyzed, and subjective findings were obtained through post-experiment questionnaires and interviews. The National Tactical Data Systems symbology produced significantly better results than the two other symbologies, and was favored most by subjects. This presentation describes the study and offers an explanation of the results based on Anne Triesman's findings of preattentive visual processing.”
“The objective was to structure the concept of workload in a practical way which would permit Human Factors Systems Engineers to apply this concept to various phases of the development process. Workload is a qualitative rather than absolute concept which, like motivation, is inferred to exist by measuring the relative behavioral reactions to certain conditions. Workload may be thought of as an intervening variable between physical, mental, visual, vocal, or auditory antecedent conditions, and whatever performance-based, subjective or physiological measures that may be sensitive enough to reflect changes in the antecedent conditions. The practical approach has been to consider workload as the number of things to do modified by the level of difficulty. This concept has successfully permitted HF Systems Engineers to assess operator workload at progressive levels of system development.”
“This paper discusses the importance of a carefully developed set of control and display standards and conventions for submarine combat systems, and the use of a requirements data base and rapid prototyping to assist in their definition. Some of the human factors issues that are confronted when attempting to develop a useful set of control and display standards are discussed. The requirements data base is also being used to assure that the proper level of interface consistency is achieved across functional interfaces. The data base incorporates attributes of Navy specified control and display requirements and attributes imposed by the human factors engineer. The data base attributes and its potential uses for defining and managing operator interface requirements are discussed.”
“Computer simulation of the operator/system interface is a useful tool for supporting system software design. Simulation is also a flexible and cost effective method for applying human engineering analysis techniques as required by MIL-H-46855 (Human Engineering Requirements for Military Systems, Equipment and Facilities). This paper describes the integrated methodology used to model the operator/computer interaction for a newly developed military system. The operator/computer interface was potentially complex since the operators were required to control several sensors as well as communicate intelligence information within specified time constraints. In order to focus the design process and optimize the operator/computer interface, a computer simulation using the Micro SAINT software package was performed. This simulation provided a dynamic and integrated approach for performing subsequent design trade offs and developing software interface specifications and requirements.”
“This report describes human factors engineering participation in the design of a system manager's workstation. The project entailed the integration of 6 different keyboards and a wide variety of display subsystems into a single keyboard and 5 CTR displays. Due to the complexity of the system, a team approach to the design was taken which entailed instructing and guiding experts in the use of human factors principles in the development of designs. The results were well received by a review committee of system experts while being developed within an extremely time compressed schedule.”
“The Human Factors Engineering products from the systems requirements phase of system development were transformed into techniques consistent with structured software development techniques. These techniques supported definition of the mission functions with the context diagram; the task list was compatible with the event list; and high level functional flow diagrams are consistent with the structured data flow diagrams. In addition, the sequenced task analysis procedures used provided a structured diagraming methodology in state transition diagrams. This technique provided a method for defining MMI requirements in software engineering terminology.”
“The identifiability of sounds used in the Meaningful Sounds Identification test was measured. Identifiability was quantified with a measure of identification uncertainty. Calculation of this measure involves sorting the identification responses into categories of similar causes. Two exemplar sets of the sounds were used and the response data were analyzed separately by two sorters. All of the sounds were not highly identifiable, as was expected given the use of the test. The results were comparable for the two sets of exemplars, and for the two sorters. The results demonstrate the importance of quantifying sound identifiability.”
“This paper is concerned with the relationship between human reaction time for individual stimuli and their surprise values. A new measure of surprise is introduced that incorporates the probability of an individual stimulus occurring as well as the probabilities of the remaining potential stimuli. Experimental data are used to test the proposition that the reaction time for a stimulus is an increasing function of the surprise value of that stimulus. This proposition does indeed appear to be acceptable.”
“NOTE: No abstract available. The following is the first paragraph of the presentation. In some sense, human error is at the root of all transportation accidents. To paraphrase test pilot Scotty Crossfield, "We either design 'em wrong, build 'em wrong, or use 'em wrong." Crossfield's dictum appears to be comprehensive -- it is difficult to imagine any other avenues for potential mayhem induced by human error than the design, manufacture, and operation of transportation systems. And it appears to be true, as is amply demonstrated on a daily basis. Clearly this is the great challenge facing the human factors profession: how can we design, build, and operate systems so that accidents caused by human error are minimized?”
“In almost every process control situation the human supervisor has to attend to many sources of information. With large numbers of information sources the supervisor is forced to divide his attention and to acquire information through sampling. In the 60's and 70's several models of sampling with different criteria for optimal behavior, have been proposed. Behavioral data indicate, however, that human monitoring behavior can show large deviations from optimality. To account for these deviations a new model, based on sequential sampling, is proposed. Experimental testing of this model reveals the development of fixed sampling sequences and the choice of a time base for execution as important performance shaping factors.”
“A dynamic decision-making task was designed for a 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.”
“The effects of speed and accuracy conditions on single and double stimulation task performance were investigated and compared along with the effects of stimulus complexity and interstimulus interval. The proportion of error responses increased when the complexity of the stimuli increased under speed and accuracy conditions in both single and double stimulation tasks. There was, however, no trend in the proportion of error responses as a function of ISI under speed and accuracy emphases.”
“This symposium proposes macroergonomics as a vehicle for integrating human and organizational needs. The concept is defined and differentiated from more traditional studies in organizational behavior and human factors. Specific areas of focus include: conceptuation and differentiation of the unique contributions of macroergonomics; current practices and directions; integration of human and organizational data; and contemporary issues and concerns facing researchers and writers in the field.”
“The concept of organizational design is presented and the relationship between structure and process is discussed in the context of design. Three organizational design models and their characteristics are set forth. Principal contingency variables are identified and their relationships to organizational design are discussed. Evolution of organizational design as an independent variable to the role of a dependent variable is shown. Finally, system design based upon sociotechnical systems theory is identified and discussed.”
“This article illustrates the potential contribution of macroergonomics by: 1) identifying four contemporary issues that organizations face and 2) demonstrating how a macroergonomic approach can help. These issues represent four levels of analysis -- individual, job design, organizational, and environmental. In addition to demonstrating its utility, the illustration is intended to generate action toward meeting these challenges.”
“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 education 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 safe assessment and development guide based on the newly released ANSI Robot and Robotic System safety standards.”
“This paper will review the major physical features of humans versus robots that are important in the evaluation, selection, and safe operation of robots for industrial tasks. A model for robot performance is presented and the methods for predicting the time a robot takes to complete a task will be discussed.”
“A laboratory experiment was conducted to determine the maximum speeds of robot arm motion considered by the subjects as safe for human operators working in a close proximity of the robot's working envelope. Twenty-nine college students (16 males and 13 females) participated in the study as monitors of the simulated assembly tasks performed by two industrial robots of different size and work capabilities. The results show that the speed selection process depends on the robot's physical size and its initial speed at the start of the adjustment process. Subjects selected higher speeds as "safe" if they were first exposed to maximum speed of the robot, and significantly lower values when the initial speed of the robot's actions was only 5% of maximum. It was also shown that the subject's previous exposure to robots and the level of their knowledge of industrial robots highly affected their perception of safe speeds of robot motions. Such effects differ, however, between males and females.”
“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.”
“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.”
“The identical causation hypothesis contends that identical causes or circumstances precede minor and major injuries in accidents. Tests of the identical causation hypothesis were carried out by examining frequencies of prior activities, accident events and injury events across minor and major injuries, including a breakdown by job family. Also, combinations of accident variables (scenarios) for minor and major injuries were examined. For the individual accident variables, the data clearly support a similar causation hypothesis. However, for the combinations of accident variables, differences were discerned between minor and major injuries. Overall, the present test of the identical causation hypothesis suggests that similar preceding circumstances may underlie both minor and major injuries.”
“This paper presents a review of the driving research literature in a search for evidence related to secondary task interference on driving. Driving studies employing secondary tasks fall into two broad categories: (a) studies concerned with driver workload, and (b) studies concerned with driver fatigue. A majority of these studies lack a valid theoretical basis for the application of the secondary task technique and the particular choice of secondary task. Few of them examined mutual interference between secondary tasks and driving. Some studies, however, reported interference, implying the presence of resource competition. This should be of concern to equipment designers.”
“There has always been considerable controversy in gerontology over the extent to which age-related decline on laboratory tasks generalizes to real world performance. In recent years, there has been considerable interest in assessing performance in more realistic tasks. In this panel, we will be concerned with how the aging process affects performance in domains where people had a great deal of practice with the tasks, through life-long experience or via extended practice in the laboratory. Performance in experience-related domains versus unrelated ones will also be discussed.”
“This paper presents a field experiment designed to test and evaluate two functionally different trailer hitches, conventional and newly designed, for driving effectiveness and safety. The evaluation was performed using three different approaches. The first used subjective evaluation obtained through subject questionnaire. The second involved estimating the strength required for the control of the steering wheel using electromyogram (EMG). The third involved monitoring the extent of the oscillations of the steering system of the experimental car. The independent variables were the type of hitch, driving pattern and the trailer load. Each of the six subjects participated in 24 driving runs in the experiment. The results showed that the new trailer hitch provides greater driving effectiveness and safety than the conventional trailer hitch.”
“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.”
“Multiple measures of tactical-planning performance were employed to evaluate prototype computer-based planning aids. The objectives of the evaluation were to: 1) assess the extent of overall performance improvement, if any, over existing manual methods, 2) diagnose the impact of computer-aiding on each of the different components of planning performance, and 3) identify potential deficiencies and needed improvements in specific computer-based aids. The evaluation approach was based on the decomposition of planning into specific components and the measurement of each component within a specific mission context. Within a latin-square experimental design, eight tank platoon leaders first used present paper-map methods to solve tactical problems and then used a system of computer aiding to solve comparable but different problems. Seven objective performance measures assessed different components of planning performance under map and aided conditions; an objective measure of overall mission success and subjective assessments of individual planning aids were also obtained. Results provided a multi-dimensional basis for assessing the potential value of computer-based aids and for further enhancement of the planning aids. Overall, use of the prototype planning aids resulted in a significantly greater rate of mission success, 94 percent vs. 44 percent.”
“A User Interface Management System generally separates the design space for the interface and the application. This separation may have been useful as a means for improving our understanding of interfaces, but does it really support the design of good application interfaces and more importantly good application interface styles?”
“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.”
“On-line user documentation is utilized in many of our computer systems. It is important that we measure the usage and adequacy of that documentation. The present paper reviews the philosophy and methods used in an AT&T study of the usage of on-line documentation. The study, initiated and implemented by a Human Factors Specialist, shows the benefits of measuring the usage and analysing the results.”
“Physical learning environments for computers require special consideration and design. The better this "electronic classroom" environment is designed, the greater are the chances that the desired learning will occur. The design/selection of acoustical, lighting, HVAC factors and space/furniture affect each individual. Physical environments effects student learning, physiology and affect. Behavioral science data regarding color, form, acoustics, light intensity, light contrast, and temperature is useful when designing spaces for learning via computer. In this paper we will examine many of the environmental factors which facilitate or inhibit student progress.”
“The Vertical Takeoff and Landing Simulator (VTOL) at the Naval Training Systems Center's (NTSC) Visual Technology Research Simulator (VTRS) was used to study the effects of simulator design features on pilot performance in helicopter shipboard landings. The research was designed to evaluate the effects of current design features on the SH-60B Operation Flight Trainer (OFT) used to train helicopter shipboard landing and four proposed simulator design modifications. These were: (1) scene detail (SH-60B OFT scene versus an upgraded VTRS scene), (2) field-of-view (VTRS wide versus a smaller SH-60B OFT field-of-view), (3) dynamic seat cueing (on versus off), and (4) dynamic inflow (standard rotor model available in existing trainers versus an updated rotor model). These factors were tested across two levels of seastate. On the basis of the factors studied in the experiment, the wider field-of-view, the more detailed scene and the rotor model, are recommended for use. The dynamic seat cueing evaluated in this study is not recommended at this time.”
“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 includes a variety of visual scene generations from general purpose microcomputer-based imagery to dedicated state-of-the-art computer systems 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.”
“While the nature of the eye and head displacements to target acquisitions in the horizontal plane have been frequently studied, such investigations in the vertical plane are somewhat scarce. In the experiment reported herein the final displacements of the head, eye, and gaze were examined for target acquisitions in the vertical and horizontal planes. The subjects' task was to fixate on a central target until receiving a verbal command to fixate on one of four peripheral targets. The analysis of the mean head, eye, and gaze displacement data to the target locations suggests similar trends across the vertical and horizontal planes.”
“Four models describing how people might acquire targets that dynamically vary in size were examined; two that described movement speed as a simple function of target size (either initial or final) and two that described movement speed as a function of the predicted size of the targets at a fixed time in the future (one was referenced to the beginning of the reaction time phase, and the other to the end of this phase). It was found that movement time was best described as a function of a size prediction made at the end, rather than the start, of the reaction time phase. Subjective workload ratings primarily reflected the total amount of time needed to acquire the targets rather than the time pressure imposed by the diminishing size of these targets.”
“This paper describes the kind of software tools which are needed for the design of applications user interfaces for telecom equipment. The emphasis is on applications programs, not window managers or compilers, concentrating on a range of applications, each of which has a distinct style and user community. The design tools we develop must encourage in-depth knowledge of these applications, and must be able to work easily within the parameters of the style for each. No single criterion defines a tool with the best fit to our needs, and no single tool or package meets those needs across the range of application styles and design stages.”
“Multiple resource theory suggests that distributing demands over separate resources will reduce resource competition and improve time-sharing efficiency. A recent hypothesis, however, suggests that the benefits of using separate resources for the time-shared tasks may be mitigated if the two tasks are integrated. The present experiment examined the benefits of distributing the input demands of two tracking tasks as a function of task integrality. Visual and auditory compensatory tracking tasks were used. Time-sharing two tracking tasks with the same order of control is said to be more integrated than with different orders of control. Results show that presenting the two tracking signals in two input modalities did not improve time-sharing efficiency. This was attributed to the difficulty insensitivity phenomenon. Whether utilizing the same control dynamics between the time-shared tasks could generate an integrality effect was unclear from the present data. A continuous auditory task that could offer comparable spatial information as the visual counterpart was proposed to be valuable for studying attentional processes, information display alternatives, and workload assessment.”
“Basic research related to the development of a new visual display technology is described. Essentially, this technology enables the serial presentation of independent frames of visual information via a single display window. Experiment 1 compared the serial display with a conventional display consisting of three spatially separated windows which subjects accessed by making saccadic eye movements. The performance measure was time per frame of information for 90% correct responding, called the duration threshold. Large time differences were found, with faster information communication for the serial display in all subjects. Experiment 2 measured the duration threshold in a serial display as a function of the number of sequentially presented frames, which varied between one and twelve. Word search and word recognition tasks were studied. The results showed an approximately linear increase in threshold with number of frames for both tasks.”
“An important consideration for some types of flight simulation is that sufficient visual information be provided for a perception of self-motion. A general conclusion of earlier research is that peripheral stimulation (outside a 30 deg. diameter area of the central visual field) is necessary for perceived self-motion to occur. More recently Andersen and Braunstein (1985) demonstrated that induced self-motion could occur when visual information simulating forward motion of the observer was presented to a limited area of the central visual field. In the present study, the perception of induced roll vection (rotation about the line of sight) from visual stimulation of the central visual field was examined. Subjects viewed computer generated displays that simulated observer motion relative to a volume of randomly positioned points. Two variables were examined: 1) the presence or absence of a simulated forward motion, and 2) the presence of a 15 deg. or 30 deg. sinusoidal roll motion. It was found that: 1) induced roll vection occurred with stimulation restricted to a 10 deg. diameter area of the central visual field; 2) greater postural instability occurred for displays with a 30 deg. roll as compared to a 15 deg. roll; and 3) significantly greater postural instability occurred along the X-axis (left/right) as compared to the Y-axis (front/back). The implications of this research for flight simulation will be discussed.”
“An experiment was conducted to evaluate user performance with a voice/phone management system for a personal computer. An experimental group of 11 subjects performed seven common voice communication tasks with the automated system using a touch-tone telephone. A control group of 10 subjects performed the same tasks by calling a dedicated human secretary. Experimental subjects gave favorable subjective ratings to system features despite poor performance. Control subjects performed most tasks faster than experimental subjects. Control subjects worked with the secretary in a more direct and goal-oriented way than experimental subjects using the automated system. The main benefit of the automated system may be its availability when human support is limited.”
“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 cals, 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.”
“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.”
“In recent years, considerable effort has been focused on the development of computational models of expert human performance. One class of expertise that has been studied is that of human tutors. The resultant intelligent tutoring systems are intended to provide the user with the "instructional advantage that a sophisticated human tutor can provide," (Anderson, Boyle and Reiser, 1985). This line of research is of interest to the human factors community for two reasons: 1. Intelligent tutoring systems offer potential tools for use in training and educational programs, a long-standing area of interest to human factors researchers and practitioners; 2. there are many human factors and human performance issues that should be addressed in the design of such tutoring systems. The speakers in this special session will provide an overview of research issues in the design of intelligent tutoring systems. Relevant conceptual issues and approaches will be highlighted in the context of a variety of application areas. Included will be a discussion of the "use of intelligent system monitors that allow users to integrate the time and effort spent on learning with actual use of a system", (Carroll and McKendree, 1987).”
“To design intelligent interfaces it can be useful to start from a consideration of what users already know and expect to do. This is not the only way to design intelligent interfaces and in fact not the typical method in practice. Several examples are discussed to urge that current practice be broadened to correct this.”
“Human factors research programs within commercial industries are frequently avoided because of escalating costs associated with data collection and reduction. Other prohibiting factors limiting the use of traditional research methods in industry are manpower costs, accounting procedures for overhead allocation, and the availability of qualified personnel. The department of computer and Electrical Engineering Technology at Kent State University, Tuscarawas Campus has developed a program for supporting projects from the NCR Human Factors Department of the Retail Systems Division. This program has provided students an opportunity to (1) acquire new skills rarely experienced in classroom assignments; (2) obtain financial assistance, and (3) obtain exposure to potential employers. This program began as a pilot and has continued to grow because of the demand in retail businesses for the work supported by the students.”
“Eighty-five senior cadets participated in a class exercise involving complex decision-making in a natural context. One experimental group was induced to employ explicit decisional processing and another was allowed to simply guess appropriate responses. Decision accuracy was measured at three levels of information availability. Both groups performed significantly above the level of chance when no reliable, objective information was provided. However, neither accurate base rate information nor conditional probabilities increased the decision accuracy of either experimental group. The group allowed to simply guess made significantly more accurate responses than did the group induced to explicate their decisional choices. These results provide convergent support for the dissociation of implicit and explicit knowledge. The exercise itself was a useful combination of research and experiential learning and encouraged classroom discussions of many issues related to human decision making.”
“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.”
“The author spent two months as a Faculty member participating in a faculty exchange program in the People's Republic of China. While there, he taught an undergraduate course in Human Factors Engineering in Machine and Workplace design. He also conducted a week long seminar for factory engineering personnel and engineering faculty on the same topics. He consulted with industry and traveled extensively in china during this time. This paper is based on his experiences and observations. Specific topics are: 1) quality and nature of students in the PRC vs. the US, Japan and Europe; 2) Programs in Human Factors in the PRC; 3) Academic Engineering Laboratories in the PRC and 4) Safety Engineering in the PRC.”
“The term "User Interface Management System" seems to mean different things. In the article which first coined the term, Kasik defined the UIMS as a productivity tool for interface developers, intended to speed up the creation of interactive applications. Others consider a UIMS to be a tool for enforcing good human factors interfaces. Still others think of a UIMS as a rapid prototyping environment for experimental interfaces. Is it possible for a single tool to meet all of these needs?”
“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.”
“Studies are under way to look at the effects of vibration under spinal load. Studies have shown that static load can be identified by measuring changes of stature, but when the spine is vibrated changes of stature do not show the same simple relations to estimated load. It is deduced that the spine may be oscillating in a complex way which introduces nodes at different points along its length. Experiments will be described to show how these phenomena are being investigated and the results will be discussed.”
“In trying to understand how a human operator interacts with a complex system, it is important both from a theoretical and an applied viewpoint that we build a model of the human's behavior in such an environment. This paper briefly reviews different models of the human operator and characterizes them in terms of four conceptual dimensions: purpose, structure, content, and specificity. Methodological issues in operator modeling are also considered.”
“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.”
“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 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.”
“Even in high technology industries, many tasks in repair and maintenance involve heavy manual work and are often carried out in awkward and confined spaces. In such situations workers have great difficulty obtaining access to components and many need to adopt harmful body postures while applying high forces. These tasks are being studied in the laboratory using a CODA-3 optical scanner to record postures. The aim is to investigate the strength and reach capabilities of workers, and to develop better techniques for assessing the safety and acceptability of such tasks. One of the postures which as been studied is kneeling, for tasks which occur for instance in mining or in aircraft maintenance. Reach distance and direction of operation of controls or handtools both have a large influence on strength capability and the relationships between these and the posture adopted are discussed in the paper.”
“It has been suggested that the coefficient of friction between the finger flexor tendons and the structures over which they slide is normally quite small, but increases with irritation of the tendon. This paper utilizes a belt and pulley model of the wrist in the in vivo measurement of the frictional coefficient. An estimated value of 0.12 for the frictional coefficient was obtained from a sample of five symptom free subjects.”
“The study addresses the problem of fitting anthropometric data from different populations to proportional man models. Proportional models simulate the human shape by assuming fixed proportions between various body dimensions. Percentiles can be created in such a model but are constrained by the body proportions. Prime Computer's SAMMIE man model is an example of the proportional approach. The SAMMIE model is described with reference to the anatomical features it simulates. The constraints imposed by a proportional model are discussed. These include link lengths, flesh envelope and ranges of joint motion. A linear programming model is presented to fit available population data to the model. The program is designed with a user friendly graphic interface allowing the designer to easily of principal interest. A validation study of the method using NASA data is reported.”
“Creating partnerships between school districts and universities are seen as a way to attain educational renewal. One such partnership exists between the BYU College of Education and the public schools in Central Utah. Following the naturalistic inquiry technique, this study attempted to evaluate the partnership participants' feelings and the extent to which the organization affected those feelings. The study showed that there is an undue need for control of others by members of the Governing Board of the Partnership, manifested in a structure of domination, at the cost of positive feelings and the mutual goodwill of partners. Besides being incongruent with partnership philosophy, this controlling behavior has created a sense of lack of care by the organization. The article suggests ways to resolve this problem.”
“A university-public school partnership analysis reveals how the cultural context associated with existing institutions can both facilitate and impede the emergence of a new culture those institutions attempt to create and often involves entire cultural reforms and organizational conversion.”
“In this paper the preliminary results of a four year longitudinal study concerned with job design and levels of strain among a population of Prison Officers are reported. The job design factors that were studied related to perceived demands, constraints and supports. It was hypothesized that (i) those officers who perceive themselves as having jobs high in demand and level of constraint would suffer more strain than those of equal demand but who had a greater decision latitude (i.e., fewer constraints). It was further hypothesized that (ii) those in highly demanding and constrained jobs would show fewer strain symptoms if the environment in which they worked was perceived as providing social support. Preliminary analysis of the data shows that the first hypothesis was not supported for a measure of general physical well-being. However, there was evidence that those working in high security prisons showed significantly lower levels of general physical health than those working in low security environments. For measures of psychological well-being both hypotheses (i) and (ii) were partially supported. Those who perceived themselves as having high levels of support were found to suffer less from anxiety and depression. These effects were most apparent in the higher security prisons. Additional analyses have shown that the demands supports and constraints model is probably too simplistic and that other variables (e.g., personality) and further refinements to the model would help to account for additional variance in the measures of strain.”
“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 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.”
“This paper describes the application of affordable program management software to the task of planning human factors programs conducted in support of complex system developments. A model of the military system acquisition process was developed and a model human factors engineering program was overlaid upon it. Interdependencies were created between the models so that changes made in the acquisition schedule would cause the human factors program to be automatically tailored. This approach has potential to reduce planning time and increase the quality of human factors plans.”
“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 reconfigureable 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.”
“This paper presents the concept of an Automated Job Analysis Tool (AJAT) which predicts personnel characteristics that are required in order to ensure acceptable human-system performance with a specified system design. The scope of this tool is intended to be quite broad, applying to all types of military systems, addressing the performance of both operators and maintainers, providing a means for considering training issues, and incorporating the effects of all relevant performance-impacting factors. In order to achieve this objective, several major innovations in performance prediction technology are required; these are described in this paper in terms of AJAT requirements, current technology status, and a plan for developing and validating the required capabilities. The AJAT concept is based on the use of existing models (i.e., HOS, CAR, and possibly others) to predict performance under specified conditions and the use of a factor-analytic framework to achieve efficient mapping of the performance space of interest.”
“This paper describes an Intelligent Manual Feedwater Control Station (IMFCS) that provides on-line expert guidance for a process control task: control of feedwater during power plant startup and operation. The IMFCS provides control action advice derived from the analysis of the performance of expert operators. It represents a novel approach to advisory systems in that (a) IMCF does not attempt to replicate in detail the surface activities of domain experts, but rather abstracts the cognitive competencies required for expert performance and provides a domain representation that promotes these competencies; (b) the advice takes an analogue graphic display form; (c) a common frame of reference is established between machine advisor and human practitioner that integrates advice and "explanation" avoiding problems with opaque advice.”
“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.”
“Workload techniques may be divided into two broad classes: 1) Analytic techniques -- predictive techniques that may be applied early in system design before "operator-in-the-loop" studies; and 2) Empirical techniques -- workload measurements taken with "operator-in-the-loop" during simulator, prototype, or system evaluations. Described here are five categories of the analytic techniques: 1) Comparability Analysis; 2) Mathematical Models; 3) Expert Opinion; 4) Task Analytic Methods; and 5) Simulation Models. A description, with examples, is given for each category. The motivation for focusing on the analytic techniques lies in their application during the earliest stages of system development where the greatest design flexibility is available at the least cost.”
“Employee testing and evaluation often requires a sensitive measure of memory capability. Recognition memory is tested by those tasks which require the determination of the identity of previously presented information. In order to obtain an accurate estimate of one's discriminability in recognition memory, the decrement in sensitivity has to be distinguished from a mere criterion shift or response bias. Previous researchers found that vigilance decrements result from a decrease in perceptual sensitivity when signal discrimination loads memory and signal event rate is high. In the present study, discriminability over time was combined with various memory loads in a recognition memory experiment. Eight subjects were tested in two fifty-minute sessions, using 360 three-digit random numbers. A one-way ANOVA showed that the lag factor was significant for two parametric sensitivity measures. When the lag increased by five or more intervening numbers, a significant decrement in sensitivity was found. Below this level of memory load, no decrements in sensitivity were found.”
“The present research sought to determine whether the construction of multiple-choice alternatives based around a critical target answer would facilitate the selection of the target answer. Subjects were given a multiple-choice test consisting of 60 questions, each having four alternatives. Twenty of the 60 questions were the critical questions and were constructed to have no correct answer (i.e., asked nonsense) but appeared legitimate. One of the alternatives for the critical questions was the critical alternative, around which the other three distractor alternatives were derived. This was accomplished by systematically substituting each of the critical alternatives' three components with another plausible component. This procedure produced a set of alternatives where the critical alternative was more similar to the other alternatives than they were to each other (i.e., it was the most prototypic). The results of two experiments using ranking and proportion scores showed a response bias effect: subjects selected the critical alternatives more often than would be expected by chance. Further analyses revealed that in lower ability subjects the effect disappeared when the critical alternatives were embedded in sets of distractors which had randomly ordered components. High ability subjects selected the critical alternative more often than chance regardless of the distractors' component arrangement. The results suggest that test-makers should avoid constructing distractor alternatives around a correct alternative because the information provided in the set of alternatives may influence test-takers to select the target answer without any knowledge of the information being assessed.”
“An adaptive questionnaire is a hierarchically organized test instrument that employs contingency branching and automated question selection to focus subject judgments on issues of maximal concern. Successful demonstrations of the adaptive questionnaire approach have prompted the development of an automated adaptive questionnaire computer program that provides substantial new capabilities for the construction and employment of adaptive questionnaires and checklists. This paper describes those capabilities and discusses several applications to test and evaluation problems.”
“In an effort to reduce attrition during basic morse code training required for the Military Occupational Speciality 05H (Morse Code Intercept Operators), new measures are being sought to improve present selection methods used at the US Army Intelligence School, Ft. Devens. A test battery was used to evaluate whether certain psychological attributes (e.g. musical ability, short-term memory, attention, perceptual speed) are related to job performance. A likert-type rating scale, using 05H critical behaviors, was developed to assess on-the-job operator performance. Results revealed that (1) portions of the test battery were correlated with successful 05H performance as measured by the rating scale, and (2) some tests which did not predict performance discriminated between 05H operators and the general population. Identification of potentially predictive tests from this effort will provide the basis for the construction of a test battery to supplement current selection techniques.”
“A large-scale experimental study was conducted involving the training and testing of 123 human subjects on the Criterion Task Set (Version 1.0). Testing was performed under baseline and stressor conditions. The performance data and Subjective Workload Assessment Technique ratings for the first baseline trial (Trail 6) were analyzed using the SAS VARCLUS procedure to evaluate the structure of the CTS. Seven clusters of response time variables were identified for the nine tasks. In general, the Memory Search, Linguistic Processing and Mathematical Processing tasks were grouped in one cluster with each of the other clusters representing a single task. Five clusters were identified for the SWAT ratings with clusters differentiated along the dimensions of task difficulty and processing stage.”
“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 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.”
“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.”
“Several tasks in the Criterion Task Set have been modified as a result of validation studies conducted on the original battery. Recent research has established new loading levels for those tasks. In addition to task changes, several modifications have been made in the user interface. Added features include: a 30 second trial option, automatic trial number incrementing, a file naming convention, and a data reduction program.”
“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 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.”
“The objective of this study was to investigate alternatives for allocating the tasks associated with defensive counter measures in a fighter cockpit environment. The three methods allocated the functions either totally to the operator or a simulated expert system and dynamically at the operator's request to either. The analysis of the objective data showed there were no significant performance differences among the three treatment conditions. However, the analysis of post treatment subjective data showed the subjects did not have confidence in the simulated expert system's ability to handle the threats (p < .01) and they had a significant preference for some form of computer assistance during the missions (p < .01).”
“The objective of this research was to replicate and extend an investigation of Voice and Manual Control in Dual Task Situations previously performed by Wickens et al. (1985). This study incorporated both the previous within-subject design with a much larger sample size and a novel between-subject paradigm. The repeated measures investigation minimizing asymmetric transfer between response conditions revealed significantly better performance when a verbal Sternberg task was voice controlled in combination with a manually controlled spatial tracking task. The between-subject study likewise support this finding. The previous 1985 study's finds favoring hemispherically compatible left-handed tracking were not supported in this investigation.”
“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 of keyboard until 20 lines of text had been entered. Keyboard entry was found to slightly faster”
“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 aircrafts. 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 difference 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.”
“This paper describes an interactive computer-aiding system for tactical aircraft mission planning. A Multiple-Objective Decision-Making approach has been applied to the tactical mission planning domain. The planner specifies a set of potential flight routes and selects an optimum one as the result of a human-computer dialogue. In this dialogue, the planner iteratively specifies acceptable constraints and desired weights on several mission-related decision objectives. The system provides graphic feedback about the merit of the selected route vis a vis the specified objectives, and allows the planner to tailor the mission route plan to meet explicit decision objectives.”
“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.”
“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.”
“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 from networks of event-time sequences which occur under the various velocity conditions. The significance of these sequences to spine loading is discussed.”
“This paper presents the results from two biomechanical studies that examined the effects of loading on the L5/S1 area of the lower spine. The objective of these exploratory studies was to determine whether subject, cardiovascular, and isometric and isotonic strength variables could be used to determine a worker's risk potential for back injury. The first study examined trunk velocity and torque developed in movement against a 30 lb. resistive load for two groups of people: (1) normals (no back pathology), and (2) abnormals (people with physician-diagnosed back pathology). Significant differences were found between these two groups for back torque and velocity measures. People with back pathology developed less torque and were slower in their movements. Discriminant analysis provided an 82% correct classification for normals and abnormals using velocity and torque measurements. The second investigation studied only people with back pathology and its objective was to explore the sensitivity of the testing procedure to distinguish between different degrees of back pathology. The purpose of these studies was to develop measures that could be used to screen and place people in jobs so they would not be at risk for back injury. Further work will aim at: (1) improving the discriminant function used in the first study, (2) searching for additional measures predictive of back injury risk potential, (3) reducing the resistive loads used in testing, and (4) studying non-symmetrical loading effects on the spine.”
“Historically, manual handling of materials has consistently accounted for over 25 pct of all industrial accidents. In underground coal mining, the situation is worse. Materials-handling accidents routinely account for 30 to 35 pct of all lost-time injuries. Research sponsored by the Bureau of Mines, U.S. Dept. of the Interior, and conducted by Essex/Canyon Research, Inc., developed and evaluated several mechanical-assist devices to reduce the manual effort and the corresponding risk of injury from handling supplies and equipment in underground coal mines. The prototype devices were supplied to cooperating coal mining companies for evaluation. On-site visits, task analyses, and interviews were used to evaluate the devices. Three of them performed exceptionally well and have shown promise for reducing the amount of manual lifting and handling required underground.”
“This paper discusses two general models of user interaction in the context of user assistance (HELP) and their implications for design. Conceptual and quantitative models provide software engineers with tools that can aid them in the interface design process. The conceptual model presented is derived using a hermeneutic approach to the analysis of human-computer interaction. The interaction is modeled as a set of states and transitions between states. This suggests that user assistance should have a more central role in the design of the system. The quantitative model is derived from a study of the existing literature, and provides a framework for analyzing performance issues at the human-computer interface, using metrics like response time, keystrokes, error rates, and task completion rates. The model contains seven components, covering user characteristics, information type, structure, user knowledge, presentation, control, and access.”
“The purpose of this study was to examine the lifting capacity of low-seam coal miners in four restricted work postures (roof heights of 36", 40", 44", and 48"), investigate the associated metabolic costs, and to examine electromyographic (EMG) data from eight trunk muscles during the lifting procedure. Subjects were thirteen underground miners accustomed to handling materials in restricted work postures. Each subject performed two twenty-minute periods of asymmetric lifting in each of four postures during the day of testing. The frequency of lifting was 10 lifts per minute. A specially designed lifting box incorporated microswitches in one handle of the box and another in the bottom of the box, in order to examine the trunk muscle function at specific points during the lifting cycle. The data collected will be used by the Bureau of Mines to make recommendations for lifting materials in low-seam coal mines.”
