Search

Objective: In this review, we determine if there is evidence to demonstrate a relationship between occupational driving posture and low back pain.Background: The burden of low back pain is increasing. An understanding of this relationship is required to enable the development of recommendations for clinicians and policy-makers for the driving industry.Method: Five databases were searched up to March 12, 2018. Study quality was assessed using the National Heart, Lung, and Blood Institute's Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies, followed by a GRADE analysis to consider the evidence as a whole. A narrative, critical synthesis was completed that considered the methods by which driving posture and low back pain were measured and analyzed.Results: There were 653 articles identified, with seven eligible for review. Four articles identified an association between occupational driving posture and low back pain, yet this was based on the use of measurement tools lacking validity. Although a relationship may exist, the specific driving postures associated with low back pain and the strength of this relationship have not been confirmed.Conclusion: Future research needs to employ validated and reliable, real-time qualitative methods for measuring occupational driving posture to advance our understanding of this relationship.Application: Clinical and policy recommendations regarding driving posture and low back pain should be used with caution, as they are guided by evidence incorporating bias. Future studies are required to confirm the specific postures assumed while occupational driving and their relationship with low back pain, before recommendations can be made. [ABSTRACT FROM AUTHOR]

Newell and Card (1985) warned the human factors community that the way to deal with scientists, engineers, and designers was not through the use of platitudes or by advocating the empirical testing of an infinity of design alternatives but, rather, through the use of predictive and reliable quantitative techniques. As the scope and scale of the issues that the human factors community was asked to consider expanded, the tool chest of quantitative methods seemed to diminish. That situation appears to be changing. As the papers in this special section show, the science base and techniques available for applying that science through use of quantitative formalisms have progressed. The pendulum is swinging back, and human factors engineers are in the ascendance. Engineering quantitative formal models of human performance is the wave of the present and represents an important part of the future of our profession. [ABSTRACT FROM AUTHOR]

Objective: The aim of this paper is to provide a comprehensive and original review of the theoretical development of the individual operational cognitive readiness (OCR) theory.Background: Cognitive readiness (CR) is a concept that has the potential to predict the performance of human individuals and teams prior to engaging in complex, dynamic, and resource-limited task environments. However, the current state of the literature is confusing and laborious, with heterogeneous views regarding the theoretical frameworks among leading researchers.Method: This review (1) undertakes a systematic approach toward categorizing published CR literature into theoretical and measurement contributions across the different levels of CR, (2) carries a critical evaluation of the CR and OCR theoretical frameworks, and (3) provides directions for future research guided by gaps identified during the review process and other published literatures.Results: Results from the categorization of published CR literature provide a new, valuable, synthesized CR library for researchers to consult to streamline their CR literature review process. Critical examination of the CR and OCR theoretical frameworks leads to positing that new components should be explored for OCR.Conclusion: There are many possible directions for future research including evaluating domain-independent components of OCR and evaluating the relationship between biofeedback measures and performance in CR models.Application: The Defense domain continues to be the focal application of CR. However, CR could be used by other application domains, such as sports and emergency services, that require their working personnel to engage in complex, uncertain, and dynamic task environments. [ABSTRACT FROM AUTHOR]

Objective: This paper examines drivers' allocation of attention using response time to a tactile detection response task (TDRT) while interacting with an in-vehicle information system (IVIS) over time.Background: Longer TDRT response time is associated with higher cognitive workload. However, it is not clear what role is assumed by the human and system in response to varying in-vehicle environments over time.Method: A driving simulator study with 24 participants was conducted with a restaurant selection task of two difficulty levels (easy and hard) presented in three modalities (audio only, visual only, hybrid). A linear mixed-effects model was applied to identify factors that affect TDRT response time. A nonparametric time-series model was also used to explore the visual attention allocation under the hybrid mode over time.Results: The visual-only mode significantly increased participants' response time compared with the audio-only mode. Females took longer to respond to the TDRT when engaged with an IVIS. The study showed that participants tend to use the visual component more toward the end of the easy tasks, whereas the visual mode was used more at the beginning of the harder tasks.Conclusion: The visual-only mode of the IVIS increased drivers' cognitive workload when compared with the auditory-only mode. Drivers showed different visual attention allocation during the easy and hard restaurant selection tasks in the hybrid mode.Application: The findings can help guide the design of automotive user interfaces and help manage cognitive workload. [ABSTRACT FROM AUTHOR]

Objective: This paper aims to describe and test novel computational driver models, predicting drivers' brake reaction times (BRTs) to different levels of lead vehicle braking, during driving with cruise control (CC) and during silent failures of adaptive cruise control (ACC).Background: Validated computational models predicting BRTs to silent failures of automation are lacking but are important for assessing the safety benefits of automated driving.Method: Two alternative models of driver response to silent ACC failures are proposed: a looming prediction model, assuming that drivers embody a generative model of ACC, and a lower gain model, assuming that drivers' arousal decreases due to monitoring of the automated system. Predictions of BRTs issued by the models were tested using a driving simulator study.Results: The driving simulator study confirmed the predictions of the models: (a) BRTs were significantly shorter with an increase in kinematic criticality, both during driving with CC and during driving with ACC; (b) BRTs were significantly delayed when driving with ACC compared with driving with CC. However, the predicted BRTs were longer than the ones observed, entailing a fitting of the models to the data from the study.Conclusion: Both the looming prediction model and the lower gain model predict well the BRTs for the ACC driving condition. However, the looming prediction model has the advantage of being able to predict average BRTs using the exact same parameters as the model fitted to the CC driving data.Application: Knowledge resulting from this research can be helpful for assessing the safety benefits of automated driving. [ABSTRACT FROM AUTHOR]

Objective: The aim is to provide a high-level synthesis of human factors research that contributed to the development of detect-and-avoid display requirements for unmanned aircraft systems (UAS).Background: The integration of UAS into the U.S. National Airspace System is a priority under the Federal Aviation Administration's Modernization and Reform Act. For UAS to have routine access to the National Airspace System, UAS must have detect-and-avoid capabilities. One human factors challenge is to determine how to display information effectively to remote pilots for performing detect-and-avoid tasks.Method: A high-level review of research informing the display requirements for UAS detect-and-avoid is provided. In addition, description of the contributions of human factors researchers in the writing of the requirements is highlighted.Results: Findings from human-in-the-loop simulations are used to illustrate how evidence-based guidelines and requirements were established for the display of information to assist pilots in performing detect-and-avoid. Implications for human factors are discussed.Conclusion: Human factors researchers and engineers made many contributions to generate the data used to justify the detect-and-avoid display requirements. Human factors researchers must continue to be involved in the development of standards to ensure that requirements are evidence-based and take into account human operator performance and human factors principles and guidelines.Application: The research presented in this paper is relevant to the design of UAS, the writing of standards and requirements, and the work in human-systems integration. [ABSTRACT FROM AUTHOR]

Objective: This paper investigates driver engagement with vehicle automation and the transition to manual control in the context of a phenomenon that we have termed vicarious steering-drivers steering when the vehicle is under automated control.Background: Automated vehicles introduce many challenges, including disengagement from the driving task and out-of-the-loop performance decrement. We examine drivers' steering behavior when the automation is engaged, and steering input has no effect on the vehicle state. Such vicarious steering is a potential indicator of engagement for evaluating automated vehicles.Method: A total of 32 female and 32 male drivers between 25 and 55 years of age participated in this experiment. A 2 × 2 between-subject design combined control algorithms and instructed responsibility. The control algorithms (lane centering and adaptive) were intended to convey the capability of the automation. The adaptive algorithm drifted across the lane center when latent hazards were present. The instructed levels of responsibility (driver primarily responsible and automation primarily responsible) were intended to replicate the admonitions of owners' manuals.Results: The adaptive algorithm increased vicarious steering (p < .001), but instructed responsibility did not (p = .67), and there was no interaction between the algorithm and the responsibility (p = .75). Vicarious steering was associated with an increase in transitions to manual control and glances to the road but was negatively associated with driving performance immediately after the transition to manual control.Conclusion: Vicarious steering is a promising indicator of driver engagement when the vehicle is under automated control and automation algorithms can promote engagement. [ABSTRACT FROM AUTHOR]

Objective: To lay the foundation for a framework of just-in-time support (JITS) for novices dealing with urgent, unfamiliar tasks, and to evaluate a JITS system.Background: More than 350,000 people die annually of cardiac arrest in the United States. In response, automated defibrillators are advocated that, unfortunately, do not provide important respiratory support. This paper presents elements of a framework for a JITS system that instructs a lay responder to follow a treatment protocol for integrating respiratory support with the use of an automatic external defibrillator.Method: We simulated a medical emergency using a high-fidelity patient simulator and asked participants to care for the patient.Results: When using a paper-based NASA treatment protocol, participants made more errors and took longer to stabilize the injured person than when using the JITS system.Conclusion: These findings demonstrate the benefit of a JITS system to instruct novices in unfamiliar tasks.Application: The JITS system has the potential to improve the treatment outcome of victims of cardiac arrest. The JITS framework can be applied to many situations in which novices deal with urgent tasks without expertise available. [ABSTRACT FROM AUTHOR]

This paper discusses a formal and rigorous approach to the analysis of operator interaction with machines. It addresses the acute problem of detecting design errors in human-machine interaction and focuses on verifying the correctness of the interaction in complex and automated control systems. The paper describes a systematic methodology for evaluating whether the interface provides the necessary information about the machine to enable the operator to perform a specified task successfully and unambiguously. It also addresses the adequacy of information provided to the user via training material (e.g., user manual) about the machine's behavior. The essentials of the methodology, which can be automated and applied to the verification of large systems, are illustrated by several examples and through a case study of pilot interaction with an autopilot aboard a modern commercial aircraft. The expected application of this methodology is an augmentation and enhancement, by formal verification, of human-automation interfaces. [ABSTRACT FROM AUTHOR]

The Federal Aviation Administration's effort to automate air traffic control (ATC) requires that the functionality provided today be captured in future systems. We report the first quantitative naturalistic observation of paper flight progress strip interactions during operational use. Strip use was similar in a variety of situations, but some uses varied as a function of altitude, staffing, or the cooperative style used by controller teams. Design of automation should proceed by prioritizing changes based on frequency of use and importance and should ensure that an effective method of interacting with flight information is incorporated. In addition to applied relevance to the ATC domain, the results touch on several theoretical concerns relevant to dynamic environments. Actual and potential applications of this research include the establishment of a database of strip activity and an arsenal of information valuable to system designers. [ABSTRACT FROM AUTHOR]

Prior research examined how controllers plan in their traditional environment and identified various information uncertainties as detriments to planning. A planning aid was designed to reduce this uncertainty by perceptually representing important constraints. This included integrating spatial information on the radar screen with discrete information (planned sequences of air traffic). Previous research reported improved planning performance and decreased workload in the planning aid condition. The purpose of this paper was to determine the source of these performance improvements. Analysis of computer interactions using log-linear modeling showed that the planning interface led to less repetitive--but more integrated--information retrieval compared with the traditional planning environment. Ecological interface design principles helped explain how the integrated information retrieval gave rise to the performance improvements. Actual or potential applications of this research include the design and evaluation of interface automation that keeps users in active control by modification of perceptual task characteristics. [ABSTRACT FROM AUTHOR]

Objective: This research investigates security screeners' knowledge and the effect that differences in knowledge have on the performance of problem-solving activities. We argue that the development of problem-solving knowledge enables security screeners to perform effective problem-solving activity, which assists search and decision-making processes.Background: Airport security screening research has investigated the many variables that affect security screeners' search and decision making during simulated threat-detection tasks. Although search and decision making are essential aspects of security screening, few studies have investigated the problem-solving knowledge and activities that support security screening task performance.Method: Sixteen more-experienced and 24 less-experienced security screeners were observed as they performed x-ray screening in the field at an Australian international airport's departure security checkpoint. Participants wore eye-tracking glasses and delivered concurrent verbal protocol.Results: When interacting with other security screeners, more-experienced screeners demonstrated situational knowledge more than less-experienced screeners, whereas less-experienced screeners experienced more insufficient knowledge. Lag-sequential analysis using combined data from both screener groups showed that situational knowledge facilitated effective problem-solving activity to support search and decision making. Insufficient knowledge led screeners to seek assistance and defer decision making.Conclusion: This study expands current understandings of airport security screening. It demonstrates that security screeners develop knowledge that is specific to problem solving. This knowledge assists effective problem-solving activity to support search and decision making, and to mitigate uncertainty during the x-ray screening task.Application: Findings can inform future security screening processes, screener training, and technology support tools. Furthermore, findings are potentially transferable to other domains. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study was to test the predictions of the routine-failure trade-off (or lumberjack) model in a full-scope simulator study with expert operators performing realistic control tasks.Background: A meta-study of degree of automation (DOA) studies concluded that DOA predicts task performance under both routine and automation failure conditions, workload, and situation awareness. Empirical support for this conclusion appears to be weak for complex work situations.Method: A full-scope nuclear power plant simulator experiment was conducted in which licensed operating crews completed realistic procedure execution tasks. Dependent measures selected from the lumberjack model were collected and analyzed for systematic effects.Results: Situation awareness increased with increasing DOA, which contradicts the lumberjack model. Anticipated workload and failure task performance effects were not observed.Conclusion: The experimental results add further evidence challenging the applicability of the lumberjack model to complex work situations.Application: Practitioners should use caution when extending the predictions of the lumberjack model based on data from simple work situations to complex work situations. Researchers should invest more resources in testing the predictive power of the lumberjack model in complex work situations. [ABSTRACT FROM AUTHOR]

Objective: We provide a review and analysis of much of the published literature on binocular rivalry that is relevant to the design and use of head-worn displays (HWDs).Background: This review draws heavily from both the basic vision literature and applied HWD literature in order to help provide insight for minimizing the effects of binocular rivalry when HWDs are worn.Method: Included in this review are articles and books found cited in other works as well as articles and books obtained from an Internet search.Results: Issues discussed and summarized are (a) characteristics of binocular rivalry, (b) stimulus factors affecting rivalry, (c) cognitive variables affecting rivalry, and (d) tasks affected by rivalry.Conclusion: This paper offers a set of recommendations for minimizing the effects of binocular rivalry when HWDs are used as well as recommendations for future research.Application: Considerations of the basic vision literature on binocular rivalry will provide insight for future design solutions for HWDs. [ABSTRACT FROM AUTHOR]

Objective: This paper's first objective is to determine whether motor priming assistance (consisting of directional steering wheel vibrations) can be of some benefit compared with more traditional auditory (lateralized sound) or vibratory (symmetric steering wheel oscillation) warning devices. We hypothesize that warning devices favor driving situation diagnosis, whereas motor priming can improve the initiation of action even further. Another objective is to assess the possible benefits of using multimodal information by combining auditory warning with simple steering wheel vibration or motor priming.Background: Within the context of active safety devices, the experiment dealt with moderately intrusive driving assistance devices that intervene when a certain level of risk in terms of lane departure is reached.Method: An analysis of the steering behavior of 20 participants following episodes of visual occlusion was carried out. Five warning and motor priming devices were compared.Results: All tested devices improved the drivers' steering performance, although their effects were modulated by the drivers' risk assessment. However, performance improvements were found to be greater with a motor priming device. No additional performance enhancement was observed when auditory warning was added to steering wheel vibration or motor priming devices.Conclusion: This study confirms the hypothesis that the direct intervention of motor priming at the action level is more effective than a simple warning, which intervenes upstream in situation diagnosis. Multimodal information did not seem to improve driver performance.Application: This study proposes a new kind of lateral control assistance, which acts at a sensorimotor level, in contrast with traditional warning devices. [ABSTRACT FROM AUTHOR]

Objective: The present study developed and tested a model of car following by human drivers.Background: Previous models of car following are based on 3-D parameters such as lead vehicle speed and distance information, which are not directly available to a driver. In the present paper we present the driving by visual angle (DVA) model, which is based on the visual information (visual angle and rate of change of visual angle) available to the driver.Method: Two experiments in a driving simulator examined car-following performance in response to speed variations of a lead vehicle defined by a sum of sine wave oscillations and ramp acceleration functions. In addition, the model was applied to six driving events using real world-driving data.Results: The model provided a good fit to car-following performance in the driving simulation studies as well as in real-world driving performance. A comparison with the advanced interactive microscopic simulator for urban and nonurban networks (AIMSUN) model, which is based on 3-D parameters, suggests that the DVA was more predictive of driver behavior in matching lead vehicle speed and distance headway.Conclusion: Car-following behavior can be modeled using only visual information to the driver and can produce performance more predictive of driver performance than models based on 3-D (speed or distance) information.Application: The DVA model has applications to several traffic safety issues, including automated driving systems and traffic flow models. [ABSTRACT FROM AUTHOR]

Objective: This paper introduces a robust, real-time system for detecting driver lane changes.Background: As intelligent transportation systems evolve to assist drivers in their intended behaviors, the systems have demonstrated a need for methods of inferring driver intentions and detecting intended maneuvers.Method: Using a "model tracing" methodology, our system simulates a set of possible driver intentions and their resulting behaviors using a simplification of a previously validated computational model of driver behavior. The system compares the model's simulated behavior with a driver's actual observed behavior and thus continually infers the driver's unobservable intentions from her or his observable actions.Results: For data collected in a driving simulator, the system detects 82% of lane changes within 0.5 s of maneuver onset (assuming a 5% false alarm rate), 93% within 1 s, and 95% before the vehicle moves one fourth of the lane width laterally. For data collected from an instrumented vehicle, the system detects 61% within 0.5 s, 77% within 1 s, and 84% before the vehicle moves one-fourth of the lane width laterally.Conclusion: The model-tracing system is the first system to demonstrate high sample-by-sample accuracy at low false alarm rates as well as high accuracy over the course of a lane change with respect to time and lateral movement.Application: By providing robust real-time detection of driver lane changes, the system shows good promise for incorporation into the next generation of intelligent transportation systems. [ABSTRACT FROM AUTHOR]

Objectives: This paper examines the effects of new technology on team communication and information flow in a complex work environment, and offers design suggestions for improved team performance.Background: Case study of a robot-assisted cholecystectomy procedure revealed teamwork disruption and an increase in the complexity of information flow and communication in the operating room as a result of the novel technology. A controlled experiment using a between-subjects design was conducted to test the hypothesis that providing critical information in a timely and accessible manner would increase communication efficiency and reduce errors in task performance.Methods: Eighteen pairs of participants took part in a simulated tool-changing task in surgery under one of three communication conditions: (a) no rules, (b) scripted, or (c) automated.Results: Teams in the scripted and automated conditions performed significantly faster than the no-rules teams (p < .05). Teams in the automated condition made significantly more errors than those in the scripted condition (p < .05).Conclusion: Scripted speech can facilitate team communication and adaptation to new technology; automatic information display interfaces are not useful if the modality is incompatible with operator expectations.Application: Information displays and communication protocols can be designed to ease adaptation to complex operating room technology. [ABSTRACT FROM AUTHOR]

Objective: We provide a review and analysis of much of the published literature on visual perception issues that impact the design and use of head-mounted displays (HMDs).Background: Unlike the previous literature on HMDs, this review draws heavily from the basic vision literature in order to help provide insight for future design solutions for HMDs.Method: Included in this review are articles and books found cited in other works as well as articles and books obtained from an Internet search.Results: Issues discussed include the effect of brightness and contrast on depth of field, dark focus, dark vergence, and perceptual constancy; the effect of accommodation-vergence synergy on perceptual constancy, eyestrain, and discomfort; the relationship of field of view to the functioning of different visual pathways and the types of visual-motor tasks mediated by them; the relationship of binocular input to visual suppression; and the importance of head movements, head tracking, and display update lag.Conclusion: This paper offers a set of recommendations for the design and use of HMDs.Application: Consideration of the basic vision literature will provide insight for future design solutions for HMDs. [ABSTRACT FROM AUTHOR]

Objective: This paper describes an experiment directed toward refinement and initial field testing of two potential countermeasures for the problem of rear-end (RE) crashes. The countermeasures consist of "imminent warning" signals intended to direct the following driver's visual glance to the lead vehicle as it brakes rapidly to a stop and for a short time thereafter.Background: RE crashes are the most frequently occurring type of light vehicle crash, making up at least 25% of all crashes.Method: A preliminary experiment was conducted to facilitate improvement of the attention-getting capability of an alternating pair of lamps. In the main experiment, an oscillating narrow beam lamp (a promising candidate from a previous experiment) and an improved alternating pair (improved as compared with that in a previous experiment) were compared with ordinary rear lighting. Seventy-two drivers were purposely distracted by in-vehicle tasks as the lead (surrogate) vehicle braked hard.Results: Results showed improvements of 0.25 to 0.35 s in brake activation times for the two enhanced configurations as compared with ordinary rear lighting.Conclusion: The two enhanced lighting configurations show promise in reducing the number and severity of RE crashes.Application: The methods and results of this study can be applied to the future design and evaluation of automotive rear-end lighting designed to reduce RE crashes. [ABSTRACT FROM AUTHOR]

Objective: Two experiments were conducted to examine the effects of vision and masking friction on contact perception and compliance differentiation thresholds in a simulated tissue-probing task.Background: In minimally invasive surgery, the surgeon receives limited haptic feedback because of the current design of the instrumentation and relies on visual feedback to judge the amount of force applied to the tissues. It is suggested that friction forces inherent in the instruments contribute to errors in surgeons' haptic perception. This paper investigated the psychophysics of contact detection and cross-modal sensory processing in the context of minimally invasive surgery.Method: A within-subjects repeated measures design was used, with friction, vision, tissue softness, and order of presentation as independent factors, and applied force, detection time, error, and confidence as dependent measures. Eight participants took part in each experiment, with data recorded by a custom force-sensing system.Results: In both detection and differentiation tasks, higher thresholds, longer detection times, and more errors were observed when vision was not available. The effect was more pronounced when haptic feedback was masked by friction forces in the surgical device (p < .05).Conclusion: Visual and haptic feedback were equally important for tissue compliance differentiation.Application: A frictionless endoscopic instrument can be designed to restore critical haptic information to surgeons without having to create haptic feedback artificially. [ABSTRACT FROM AUTHOR]

Objective: This paper explores the development of a rigorous computational model of driver behavior in a cognitive architecture--a computational framework with underlying psychological theories that incorporate basic properties and limitations of the human system.Background: Computational modeling has emerged as a powerful tool for studying the complex task of driving, allowing researchers to simulate driver behavior and explore the parameters and constraints of this behavior.Method: An integrated driver model developed in the ACT-R (Adaptive Control of Thought-Rational) cognitive architecture is described that focuses on the component processes of control, monitoring, and decision making in a multilane highway environment.Results: This model accounts for the steering profiles, lateral position profiles, and gaze distributions of human drivers during lane keeping, curve negotiation, and lane changing.Conclusion: The model demonstrates how cognitive architectures facilitate understanding of driver behavior in the context of general human abilities and constraints and how the driving domain benefits cognitive architectures by pushing model development toward more complex, realistic tasks.Application: The model can also serve as a core computational engine for practical applications that predict and recognize driver behavior and distraction. [ABSTRACT FROM AUTHOR]

This paper describes a paradigm for human/automation control sharing in which the automation acts through a motor coupled to a machine's manual control interface. The manual interface becomes a haptic display, continually informing the human about automation actions. While monitoring by feel, users may choose either to conform to the automation or override it and express their own control intentions. This paper's objective is to demonstrate that adding automation through haptic display can be used not only to improve performance on a primary task but also to reduce perceptual demands or free attention for a secondary task. Results are presented from three experiments in which 11 participants completed a lane-following task using a motorized steering wheel on a fixed-base driving simulator. The automation behaved like a copilot, assisting with lane following by applying torques to the steering wheel. Results indicate that haptic assist improves lane following by least 30%, p < .0001, while reducing visual demand by 29%, p < .0001, or improving reaction time in a secondary tone localization task by 18 ms, p = .0009. Potential applications of this research include the design of automation interfaces based on haptics that support human/automation control sharing better than traditional push-button automation interfaces. [ABSTRACT FROM AUTHOR]

This paper presents initial information on the development and validation of three team task analysis scales. These scales were designed to quantitatively assess the extent to which a group of tasks or a job is team based. During a 2-week period, 52 male students working in 4-person teams were trained to perform a complex highly interdependent computer-simulated combat mission consisting of both individual- and team-based tasks. Our results indicated that the scales demonstrated high levels of interrater agreement. In addition, the scales differentiated between tasks that were predetermined to be individual versus team based. Finally, the results indicated that job-level ratings of team workflow were more strongly related to team performance than were aggregated task-level ratings of team-relatedness or team workflow. These results suggest that the scales presented here are an effective means of quantifying the extent to which tasks or jobs are team based. A research and practical implication of our findings is that the team task analysis scales could serve as criterion measures in the evaluation of team training interventions or predictors of team performance. [ABSTRACT FROM AUTHOR]

Resistance to change is common in ergonomic interventions, often resulting in negative consequences when the intervention's effectiveness is studied. A lab-based study assessed the effects of positive reinforcement during the intervention process. On Day 1 all participants performed a simple screw-driving task that placed stress on the cervicobrachial region through static loading. On Day 2 a control group received basic information about ergonomics and then performed the task using an ergonomic intervention that has been shown to reduce loading on these muscle groups. The experimental group received the same basic information but also received positive reinforcement while performing the task with the ergonomic intervention. Subjective task assessment surveys and body-part discomfort surveys were administered, and these, along with speed of performance, were assessed in both groups. The results showed a significantly (p < .05) more positive subjective impression of the intervention for the feedback group than for the control group (29%-57% improvement) with no real changes in either the performance or discomfort levels. Applications of this research include improving workers' acceptance of ergonomic interventions in industrial and other settings. The reinforcement technique evaluated in this paper has yielded consistently positive effects in our ongoing ergonomic intervention research. [ABSTRACT FROM AUTHOR]

This paper reports two experiments about street crossing under conditions of free flowing traffic, with a focus on modem roundabout intersections. Experiment 1 was conducted at three roundabouts varying in size and traffic volume. Six totally blind and six sighted adults judged whether gaps in traffic were long enough to permit crossing to the median (splitter) island before the next vehicle arrived. Gap distributions and measures of judgment quality are reported. Overall, blind participants were about 2.5 times less likely to make correct judgments than sighted participants, took longer to detect crossable gaps, and were more likely to miss crossable gaps altogether. However, the differences were significant only at the two higher volume roundabouts. In Experiment 2, we evaluated the response of drivers to pedestrians with and without mobility devices (i.e., long canes, dog guides). The experiment was conducted at a single-lane roundabout, a midblock crossing, and a two-way-stop-controlled intersection. Site-specific characteristics appeared to have a greater impact on drivers' yielding than did a mobility device. Actual or potential applications of this research include the development of methods for assessing pedestrian safety and driver behavior as well as identifying intersections that may require modification in order to be accessible to blind pedestrians. [ABSTRACT FROM AUTHOR]

Factors that make response selection more difficult, most notably incompatibility between displays and controls, degrade performance. The cost of incompatibility on performance is often much greater for older than for younger adults. To design products that accommodate decreased response selection capabilities of older adults, designers need to understand the specific ways in which response selection processes change with age. The purpose of the present paper is to review research on age-related changes in stimulus-response compatibility and response precuing effects, the two effects that are most directly linked to basic response selection processes. Several specific aspects of response selection that are particularly harmful for older adults' performance are identified. Potential applications of this research include initial guidelines for minimizing the effects of those aspects when designing for older adults. [ABSTRACT FROM AUTHOR]

Wearable computer comfort can be affected by numerous factors, making its assessment based on one value with one scale inappropriate. This paper presents a tool that measures wearable comfort across six dimensions: emotion, attachment, harm, perceived change, movement, and anxiety. The dimensions for these comfort rating scales were specifically developed for wearable equipment assessment by applying multidimensional scaling to a comfort term association matrix developed using the results of groupings of wearable computer comfort terms. Testing the scales on four different types of wearable computer showed that the scales can be used to highlight differences in comfort between different types of technology for different aspects of comfort. An intraclass correlation of .872 suggested that the scales were used with a high level of reliability. A second study showed that modifications made to a wearable computer resulted in improvements in comfort, although they were not significant (p > .05). A potential application for this research is as an aid to designers and researchers for assessing the wearability, in terms of comfort, of wearable computer devices and to determine the effectiveness of any modifications made to the design of a wearable device. [ABSTRACT FROM AUTHOR]

As methods in cognitive work analysis become more widely applied, questions regarding the impact of modeling choices and similarities in modeling efforts across projects and domains are increasingly relevant. However, no explicit comparison of models of similar systems has been reported. This paper compares independently developed work domain analysis (WDA) models of two command and control environments. Similarities in model content and the types of nodes included provide evidence that WDA techniques can capture fundamental elements regarding purposes and constraints. These points of agreement provide a common starting point for developing work domain representations of military command and control systems. The comparison also revealed differences between the models. Although differences in content reflected differences in scope of coverage and level of detail, other differences corresponded to more fundamental choices in modeling approach. These included the treatment of sensors, level of integration in the model, and representation of particular abstract constraints. Examination of these more fundamental differences pointed to important degrees of freedom in how to represent a WDA and clarified the implications of these modeling choices for guiding design. Actual or potential applications of this research include aiding analysts in making work domain modeling choices as well as producing work domain models of command and control environments. [ABSTRACT FROM AUTHOR]

There has been a growing movement to give commercial airliners more freedom in choosing their routes and responsibility for detecting and avoiding conflicts. These "free flight" concepts must contain new rules for assigning right of way in potential conflict situations. To evaluate the effect of prospective rules, the current paper derives the expected response of agents who exhibit different levels of sophistication. Traditional game theoretic analysis is used to derive the behavior of rational agents. Computer simulations are used to predict the behavior of boundedly rational reinforcement learners. The results reveal that several seemingly reasonable, straightforward right-of-way rules might lead to undesirable outcomes. These problematic results are robust to the assumed level of rationality. It is shown that these problems can be alleviated by using auctions to resolve competition for right of way. Actual or potential applications of this research include the usage of second price auctions to address right-of-way and similar conflicts. [ABSTRACT FROM AUTHOR]

This paper presents a conceptual analysis of dynamic hazard warning systems. The normative aspects of responses to warnings are analyzed, and a distinction is made between two forms of responses to a warning system, referred to as compliance and reliance. Determinants of the responses to warnings are identified, and they are broadly classified into normative, task, and operator factors. Existing research on warnings and automation is assessed in view of this conceptual framework, and directions for future research are discussed. Some implications of this analysis for practitioners, designers, and researchers are indicated. Actual or potential applications of this research include recommendations for the analysis, design, and study of dynamic warning systems. [ABSTRACT FROM AUTHOR]

Methodologies for assessing human judgment in complex domains are important for the design of both displays that inform judgment and automated systems that suggest judgments. This paper uses the n-system lens model to evaluate the impact of displays on human judgment and to explicitly assess the similarity between human judgments and a set of potential judgment algorithms for use in automated systems. First, the need for and concepts underlying judgment analysis are outlined. Then the n-system lens model and its parameters are formally described. This model is then used to examine a previously conducted study of aircraft collision detection that had been analyzed using standard analysis of variance methods. Our analysis found the same main effects as did the earlier analysis. However, n-system lens model analysis was able to provide greater insight into the information relied upon for judgments and the impact of displays on judgment. Additionally, the analysis was able to identify attributes of human judgments that were--and were not--similar to judgments produced by automated systems. Potential applications of this research include automated aid design and operator training. [ABSTRACT FROM AUTHOR]

This paper presents the VDM2000, a computational model of target detection designed for use in military developmental test and evaluation settings. The model integrates research results from the fields of early vision, object recognition, and psychophysics. The VDM2000 is image based and provides a criterion-independent measure of target conspicuity, referred to as the vehicle metric (VM). A large data set of human responses to photographs of military vehicles in a field setting was used to validate the model. The VM adjusted by a single calibration parameter accounts for approximately 80% of the variance in the validation data. The primary application of this model is to predict detection of military targets in daylight with the unaided eye. The model also has application to target detection prediction using infrared night vision systems. The model has potential as a tool to evaluate the visual properties of more general task settings. [ABSTRACT FROM AUTHOR]

This paper compares the effects of graphical study aids and animation on the problem-solving performance of students learning computer algorithms. Prior research has found inconsistent effects of animation on learning, and we believe this is partly attributable to animations not being designed to convey key information to learners. We performed an instructional analysis of the to-be-learned algorithms and designed the teaching materials based on that analysis. Participants studied stronger or weaker text-based information about the algorithm, and then some participants additionally studied still frames or an animation. Across 2 studies, learners who studied materials based on the instructional analysis tended to outperform other participants on both near and far transfer tasks. Animation also aided performance, particularly for participants who initially read the weaker text. These results suggest that animation might be added to curricula as a way of improving learning without needing revisions of existing texts and materials. Actual or potential applications of this research include the development of animations for learning complex systems as well as guidelines for determining when animations can aid learning. [ABSTRACT FROM AUTHOR]

The paper describes a new method for allocating work between and among humans and machines. The method consists of a series of stages, which cover how the overall work system should be organized and designed; how tasks within the work system should be allocated (human-human allocations); and how tasks involving the use of technology should be allocated (human-machine allocations). The method makes use of a series of decision criteria that allow end users to consider a range of factors relevant to function allocation, including aspects of job, organizational, and technological design. The method is described in detail using an example drawn from a workshop involving the redesign of a naval command and control (C2) subsystem. We also report preliminary details of the evaluation of the method, based on the views of participants at the workshop. A final section outlines the contribution of the work in terms of current theoretical developments within the domain of function allocation. The method has been applied to the domain of naval C2 systems; however, it is also designed for generic use within function allocation and sociotechnical work systems. [ABSTRACT FROM AUTHOR]

Visual recognition functions, such as acuity and contrast sensitivity, deteriorate rapidly over the declining luminances found during civil twilight. Thus civil twilight, a critical part of the transition between daylight and darkness, represents lighting conditions that may be useful to describe artificial illumination. Automotive headlamps project a three-dimensional beam that ranges from illumination levels comparable to daylight at the vehicle to the dark limit of civil twilight (3.3 1x) at some distance ahead. This twilight envelope is characterized as a distance beyond which foveal visual functions are severely impaired, and thus it provides a general, functional description of the useful extent of the headlamp beam. This user-centered approach to describing illumination is useful for characterizing visibility when driving at night or in other artificially lit environments. This paper discusses the twilight envelope approach and its application to intervehicle variations in headlamp systems. Actual or potential applications of this research include user-centered description of artificial illumination and driver/pedestrian safety education. [ABSTRACT FROM AUTHOR]

Users of compact smart products with small screens often have trouble learning the menu structure. If they cannot master the menu structure, users are not able to fully utilize the products. It is argued in this paper that using visual momentum in menu representation design helps users develop effective mental maps of menu structures and promotes learning of the user interface. To assess the effect of visual momentum in this study, four types of menu representations were developed. Additionally, two menu hierarchies, two types of function key layout, and two types of function key labeling were assessed to examine the effects of menu dimension and compatibility. Experimental results indicated that participants using a partial menu map with visual momentum design performed the best, and participants using a partial menu map without visual momentum performed the poorest, even worse than those-using command-only representation. The results also showed that the menu navigation problem appeared to be particularly significant with a deep menu hierarchy. Actual or potential applications of this research include menu representation design for compact smart products. [ABSTRACT FROM AUTHOR]

In two experiments, participants chose between staying on a main route with a certain travel time and diverting to an alternative route that could take a range of travel times. In the first experiment, travel time information was displayed on a sheet of paper to participants seated at a desk. In the second experiment, the same information was displayed in a virtual environment through which participants drove. Overall, participants were risk-averse when the average travel time along the alternative route was shorter than the certain travel time of the main route but risk-seeking when the average travel time of the alternative route was longer than the certain travel time along the main route. In the second experiment, in which cognitive load was higher, participants simplified their decision-making strategies. A simple probabilistic model describes the risk-taking behavior and the load effects. Actual or potential applications of this research include the development of efficient travel time information systems for drivers. [ABSTRACT FROM AUTHOR]

The rapid adoption of software to simulate human reach motions in the design of vehicle interiors and manufacturing and office workstations has required a sophisticated understanding of human motions. This paper describes how more than 3,000 right-arm reaching motions of a diverse group of participants were captured and statistically modeled. The results demonstrate that stature and age have a larger effect than does gender on reach motion postures for motions chosen by the participants while reaching to targets placed throughout a typical automobile interior. We propose that these methods, models, and results can assist the further development of human motion simulation software for ergonomic purposes, such as for the design or evaluation of vehicle interiors or industrial workplaces, to ensure that various population groups are physically accommodated. [ABSTRACT FROM AUTHOR]

This paper examines the effects of task complexity and experience on parameters of individual learning and forgetting. Three attributes of task complexity and experience are addressed: the method, machine, and material employed. The task involved a high-manual-dexterity skill taken from an operating textile assembly plant; there were 2853 individual participant learning/forgetting episodes. A parametric model of individual learning and forgetting that allows the evaluation of worker response to the attributes of task complexity and experience is discussed. Results indicate that both task complexity and experience significantly affect learning and forgetting rates. Potential applications of this research include the allocation of workers to tasks based on individual learning/forgetting characteristics. [ABSTRACT FROM AUTHOR]

Computer displays are being designed for increasingly larger industrial systems. As the application domain scales up, maintaining integration across different kinds of views becomes more challenging. This paper presents the results of a study of three different approaches to integration based on the spatial and temporal proximity of related information objects. The domain used for evaluation was a simulation of an industry-scale conventional power plant. All three displays were ecological displays developed using an abstraction hierarchy analysis. Views were integrated in a high-space/low-time, low-space/high-time, and high-space/high-time integration of means-end related objects. During a fault detection and diagnosis task, it was found that a low level of integration, high-space/ low-time, provided the fastest fault detection time. However, the most integrated condition, high-space/high-time, resulted in the fastest and most accurate fault diagnosis performance. Actual or potential applications of this research include computer displays for large-scale systems such as network management or process control, for which problem solving is critical and integration must be maintained. [ABSTRACT FROM AUTHOR]

Scaled worlds preserve certain functional relationships of a complex task environment while paring away others. The functional relationships preserved are defined by the questions of interest to the researcher. Different scaled worlds of the same task may preserve and pare away different functional relationships. In this paper we use the example of Ned to discuss the use of scaled worlds in applied cognitive research. Ned is based on a detailed cognitive task analysis of submarine approach officers as they attempt to localize an enemy submarine hiding in deep water. For Ned we attempted to preserve the functional relationships inherent in the approach officer's information environment while paring away other aspects of his task environment. Scaled worlds attempt to maintain the realism inherent in the preserved functional relationship while being tractable for the researcher and engaging to the participant. [ABSTRACT FROM AUTHOR]

Telepresence, the perception of presence within a physically remote or simulated site, has been identified as a design ideal for synthetic environments. However, confusion exists within the literature about the precise definition of telepresence. Furthermore, there is a need for a plausible and parsimonious model of telepresence. This paper identifies three types of telepresence extant in the literature: simple telepresence, cybernetic telepresence, and experiential telepresence. The third definition is the most interesting. This paper reviews the origins of experiential telepresence and the theoretical approaches commonly used to explain it. One can term these technological approaches, which emphasize the role of control/display technology, and psychological approaches, which identify experiential telepresence with known psychological phenomena. Finally, the paper presents and discusses an integrative approach to telepresence featuring a structured attentional resource model. Actual or potential applications of this research include the design of future human-machine interfaces for teleoperated robots and virtual reality systems. [ABSTRACT FROM AUTHOR]

Objective: The aim of this project was to compare texture discrimination when both touch and vision were perturbed.Background: Texture discrimination is important in the workplace. How textures are identified with the finger and with instruments when vision is magnified with lenses or video cameras is unclear.Method: Sandpaper was explored with the index finger or a metal instrument (hemostat), using normal or magnified vision. The forces generated during exploration were measured, and participants rated surface roughness.Results: With the finger, the perception of roughness was unaffected with magnification; with the instrument, magnified surfaces were perceived as rougher (p < .05). Forces during finger exploration were unaffected by magnification; forces with the instrument increased under magnification (p < .05).Conclusion: Visual characteristics of the working field can influence the exploration and perception of materials. With the finger, mechanoreceptors that directly detect textures are activated, and with the instrument, receptors sensitive to vibrations are stimulated.Application: The higher forces produced when using instruments under magnification could lead to material damage. Attenuated perception of texture when exploring with tools may lead to difficulty in accurate touch perception. This could create problems in industrial tasks such as grading wool or identifying surface imperfections on manufactured materials, as well as in clinical settings such as dentistry or surgery in which instruments are used during tissue identification. [ABSTRACT FROM AUTHOR]

The effects of vehicle package, seat, and anthropometric variables on posture were studied in a laboratory vehicle mockup. Participants (68 men and women) selected their preferred driving postures in 18 combinations of seat height, fore-aft steering wheel position, and seat cushion angle. Two seats differing in stiffness and seat back contour were used in testing. Driving postures were recorded using a sonic digitizer to measure the 3D locations of body landmarks. All test variables had significant independent effects on driving posture. Drivers were found to adapt to changes in the vehicle geometry primarily by changes in limb posture, whereas torso posture remained relatively constant. Stature accounts for most of the anthropometrically related variability in driving posture, and gender differences appear to be explained by body size variation. Large intersubject differences in torso posture, which are fairly stable across different seat and package conditions, are not closely related to standard anthropometric measures. The findings can be used to predict the effects of changes in vehicle and seat design on driving postures for populations with a wide range of anthropometric characteristics. [ABSTRACT FROM AUTHOR]

Teleoperation is frequently performed with misalignments between operator or camera viewing direction and controller orientation. Examples of this occur in endoscopic surgery and in teleoperation with multiple camera views. The objective of this study was to find a method to automatically compensate for those misalignments so that human operators performing tasks under such scenarios could achieve levels of performance comparable to aligned conditions without additional training requirements. In this paper we report on a set of experiments conducted to test a method developed for that purpose. Participants were asked to track a randomly moving target on a computer display using a cursor controlled with a joystick. Performance was recorded under various visual-motor misalignments with and without automated compensation. Results indicated significant improvements in operator performance through use of automatic compensation only under certain types of misalignment. Actual or potential applications of this research include teleoperation and endoscopic surgery. [ABSTRACT FROM AUTHOR]

Most commercial footwear is designed and manufactured on a curved last, although the amount of curvature of the last and the turning point of the last centerline have not been formally determined. In this study, we used principal component analysis to determine the foot axis so that lasts that match feet can be produced, resulting in a good fit. In evaluating 50 Hong Kong Chinese participants, we found that the center of the foot is located at approximately 52% of the foot length measuring from the back of the foot (SD = 0.65%) and that Hong Kong participants have a mean inflare (inward curvature) of 3.2 degrees. The foot center and inflare measures will help determine the fit between footwear and feet. Applications of this research include the ability to incorporate foot flare into the design and manufacture of footwear. [ABSTRACT FROM AUTHOR]

We describe an experiment to assess the influence of body movements on presence in a virtual environment. In the experiment 20 participants were to walk through a virtual field of trees and count the trees with diseased leaves. A 2 x 2 between subjects design was used to assess the influence of two factors on presence: tree height variation and task complexity. The field with greater variation in tree height required participants to bend down and look up more than in the lower variation tree height field. In the higher complexity task participants were told to remember the distribution of diseased trees in the field as well as to count them. The results showed a significant positive association between reported presence and the amount of body movement in particular, head yaw--and the extent to which participants bent down and stood up. There was also a strong interaction effect between task complexity and gender: Women in the more-complex task reported a much lower sense of presence than in the simpler task. For applications in which presence is an important requirement, the research in this paper suggests that presence will be increased when interaction techniques are employed that permit the user to engage in whole-body movement. [ABSTRACT FROM AUTHOR]