Bryan Reimer

Impact of Incremental Increases in Cognitive Workload on Physiological Arousal and Performance in Young Adult Drivers

This study examined the sensitivity of heart rate, skin conductance, and respiration rate as measures of mental workload in a simulated driving environment. Workload was systematically manipulated by using increasingly difficult levels of a secondary cognitive task. In a sample of 121 young adults, heart rate increased incrementally with increasing task demand. Significant elevations in skin conductance and respiration rate were also observed. At the lower levels of added workload, secondary task performance was nearly perfect and changes in indices of driving performance were negligible. At the highest level of workload, all three physiological measures appeared to plateau, and a subtle drop in simulated driving performance became detectable. Taken together, the pattern of results indicates that physiological measures can be sensitive to changes in workload before the appearance of clear decrements in driving performance. These findings further highlight a role for physiological monitoring as a means to measure mental workload in product design and functionality research. They also support work exploring the potential for incorporating physiological measures of driver workload and attentional state in future safety systems.

Models for recycling electronics end-of-life products

Abstract. Increasing environmental concerns about the disposal of mass produced products have resulted in efforts to take back end-of-life consumer products. Legislation aimed at forcing manufacturers to take back electronics products at the end of their useful lives has either been adopted or is impending in many countries. This, along with shrinking landfill capacity and the reluctance of communities to open new waste sinks underscores the importance of developing methods and models for the management of end-of-life materials and products. This paper reports a study of the reverse channels for recycling of electronics products. The economics of electronics recycling are modeled from the viewpoints of the generators, recyclers, and material processors separately. A variety of mathematical programming models, representative of the many ways in which the recycling industry currently operates, have been proposed along with numerical illustrations. Models integrating disassembly and material recovery decisions are also presented. These models can be used by recyclers and processors for optimizing recycling operations and thus contribute towards the economic sustainability of electronics recycling.Zusammenfassung. Zunehmende Berücksichtigung von Umweltgesichtspunkten bei der Abfallbehandlung hat zu einer Verstärkung der Bedeutung der Rücknahme von Altprodukten nach Ablauf ihrer Gebrauchsphase geführt. So wird in vielen Ländern durch gesetzgeberische Maßnahmen ein immer größerer Druck auf die Hersteller von Elektro- und Elektronikgeräten ausgeübt, ihre Erzeugnisse nach Ende ihrer Nutzungsdauer wieder zurück zu nehmen. Zugleich nehmen vorhandene Deponiekapazitäten zur Beseitigung solcher Produkte ab und es verringert sich die Neigung seitens der Gebietskörperschaften, neue Deponien zu eröffnen. Damit nimmt die Bedeutung der Entwicklung von Methoden und Modellen zum Management der Verwertung von Altprodukten in diesem Bereich immer mehr zu. Der vorliegende Beitrag befaßt ich mit der Untersuchung entsorgungslogistischer Aktivitäten im Rahmen des Recyclings von Elektronikschrott. Dabei werden die Planungsprobleme für ein ökonomisch vorteilhaftes Recycling getrennt aus der Sicht der Erzeuger, Entworger und Verwerter der Altprodukte modelliert. Zur Darstellung der Entscheidungsprobleme im Recyclingbereich wird eine Reihe von Modellen der Mathematischen Optimierung vorgestellt und mit numerischen Beispielen untermalt. Hierbei werden auch Modelle zur Integration von Demontage- und Verwertungsplanung repräsentiert. Solche Modelle können ebenso von Entsorgern wie von Verwertern zur Optimierung ihrer Recyclingaktivitäten genutzt werden.

Sensitivity of Physiological Measures for Detecting Systematic Variations in Cognitive Demand From a Working Memory Task An On-Road Study Across Three Age Groups

Objective: To assess the sensitivity of two physiological measures for discriminating between levels of cognitive demand under driving conditions across different age groups. Background: Previous driving research presents a mixed picture concerning the sensitivity of physiological measures for differentiating tasks with presumed differences in mental workload. Method: A total of 108 relatively healthy drivers balanced by gender and across three age groups (20–29, 40–49, 60–69) engaged in three difficulty levels of an auditory presentation–verbal response working memory task. Results: Heart rate and skin conductance level (SCL) both increased in a statistically significant fashion with each incremental increase in cognitive demand, whereas driving performance measures did not provide incremental discrimination. SCL was lower in the 40s and 60s age groups; however, the pattern of incremental increase with higher demand was consistent for heart rate and SCL across all age groups. Although each measure was quite sensitive at the group level, considering both SCL and heart rate improved detection of periods of heightened cognitive demand at the individual level. Conclusion: The data provide clear evidence that two basic physiological measures can be utilized under field conditions to differentiate multiple levels of objectively defined changes in cognitive demand. Methodological considerations, including task engagement, may account for some of the inconsistencies in previous research. Application: These findings increase the confidence with which these measures may be applied to assess relative differences in mental workload when developing and optimizing human machine interface (HMI) designs and in exploring their potential role in advanced workload detection and augmented cognition systems.

GLANCE ANALYSIS OF DRIVER EYE MOVEMENTS TO EVALUATE DISTRACTION

With the increasing use of in-vehicle devices in cars, an understanding of the safety implications of secondary tasks has become crucial. It is now possible to study the effects of many in-vehicle devices and tasks on driving by using head-mounted eye-tracking devices (HEDs) to collect eye positions and pupil diameters, which have been considered indicators of attentional focus. The collection of eye-position and pupil-diameter data of automobile drivers under on-road conditions and while completing various secondary tasks is described in this paper. Drivers were asked to drive on a preselected two-lane road for a total distance of 22 miles while gaze data were recorded using a HED. Longer off-road fixation durations were observed in radio-tuning and rearview mirror checking tasks, but not in the odometer checking task. In addition, the standard deviations of fixation displacements during a cognitive task involving the computation of a date for a meeting were shorter than those observed during normal driving.

Older Adult Perceptions of Smart Home Technologies: Implications for Research, Policy & Market Innovations in Healthcare

Advances in information communications technology and related computational power are providing a wide array of systems and related services that form the basis of smart home technologies to support the health, safety and independence of older adults. While these technologies offer significant benefits to older people and their families, they are also transforming older adults into lead adopters of a new 24/7 lifestyle of being monitored, managed, and, at times, motivated, to maintain their health and wellness. To better understand older adult perceptions of smart home technologies and to inform future research a workshop and focus group was conducted with 30 leaders in aging advocacy and aging services from 10 northeastern states. Participants expressed support of technological advance along with a variety of concerns that included usability, reliability, trust, privacy, stigma, accessibility and affordability. Participants also observed that there is a virtual absence of a comprehensive market and policy environment to support either the consumer or the diffusion of these technologies. Implications for research, policy and market innovation are discussed.

The validity of driving simulation for assessing differences between in-vehicle informational interfaces: A comparison with field testing

Data from on-road and simulation studies were compared to assess the validity of measures generated in the simulator. In the on-road study, driver interaction with three manual address entry methods (keypad, touch screen and rotational controller) was assessed in an instrumented vehicle to evaluate relative usability and safety implications. A separate group of participants drove a similar protocol in a medium fidelity, fixed-base driving simulator to assess the extent to which simulator measures mirrored those obtained in the field. Visual attention and task measures mapped very closely between the two environments. In general, however, driving performance measures did not differentiate among devices at the level of demand employed in this study. The findings obtained for visual attention and task engagement suggest that medium fidelity simulation provides a safe and effective means to evaluate the effects of in-vehicle information systems (IVIS) designs on these categories of driver behaviour. Statement of Relevance: Realistic evaluation of the user interface of IVIS has significant implications for both user acceptance and safety. This study addresses the validity of driving simulation for accurately modelling differences between interface methodologies by comparing results from the field with those from a medium fidelity, fixed-base simulator.

Using self-reported data to assess the validity of driving simulation data

In this article, we use self-reported driving behaviors from a written questionnaire to assess the measurement validity of data derived from a driving simulation. The issue of validity concerns the extent to which measures from the experimental context map onto constructs of interest. Following a description of the experimental methods and setting, an argument for the face validity of the data is advanced. Convergent validity was assessed by regressing behaviors observed in the driving simulator on self-reported measures of driving behaviors. Significant relationships were found across six measures: accidents, speeding, velocity, passing, weaving between traffic, and behavior at stop signs. Concurrent validity was evaluated with an analysis of simulator accident involvement and attention deficit hyperactivity disorder status. Discriminant validity was assessed using a multitrait-multimethod matrix of simulator and questionnaire data. We concluded that although the relationship between self-reported behaviors and observed responses in the simulator falls short of perfect correspondence, the data collected from the driving simulator are valid measures of the behaviors of interest.

The impact of cognitive workload on physiological arousal in young adult drivers: a field study and simulation validation

Physiological measures provide a continuous and relatively non-invasive method of characterising workload. The extent to which such measures provide sensitivity beyond that provided by driving performance metrics is more open to question. Heart rate and skin conductance were monitored during actual highway driving in response to systematically increased levels of cognitive demand using an auditory delayed digit recall task. The protocol was consistent with an earlier simulator study, providing an opportunity to assess the validity of physiological measures recorded during driving simulation. The pattern of change in heart rate with increased cognitive demand was highly consistent between field and simulator. The findings meet statistical criteria for both relative and absolute validity, although there was a trend for absolute levels to be higher under actual driving conditions. For skin conductance level, the pattern in both environments was also quite similar and a reasonable case for overall relative validity can be made. Statement of Relevance: Growing complexity and multiple demands on modern drivers’ attention highlight the significance of determining whether physiological measures provide increased sensitivity in workload detection. Better understanding, including whether simulator assessments provide valid measures of real-world response patterns, has implications in evaluating and refining interface designs and for developing advanced workload managers.

Impact of Cognitive Task Complexity on Drivers' Visual Tunneling

Cognitive distractions have been shown to affect drivers adversely and are a leading cause of accidents. Research indicates that drivers alter how they allocate their visual attention while engaging in secondary cognitive tasks. To evaluate the potential impact of secondary cognitive tasks on the allocation of drivers’ visual attention and on vehicle control, drivers were presented with increasingly complex forms of an auditory cognitive task while driving an instrumented vehicle. Measures of vehicle performance and eye gaze were assessed. Consistent with theories of visual tunneling, gaze distributions were significantly smaller while drivers performed certain levels of the secondary task; peripheral vision was thereby reduced. During the most difficult level of the secondary task, gaze dispersion was smaller than during any other level of the task. Changes in visual attention may provide earlier indications of cognitive distraction than changes in vehicle control, the latter of which were observed only during the most difficult level of the secondary task. Observed changes in vertical eye position suggest that drivers compensate for moderate cognitive demands by increasing their sight distance before further incremental increases in workload exceeded their abilities. In summary, the workload of a secondary cognitive task affected drivers’ visual attention. A low to moderate increase in workload was detectable as a change in gaze before vehicle control suffered. Gaze restriction appears related to the degree of cognitive workload. This work shows that visual attention is a potential method of detecting changes in driver state associated with cognitive workload.

On-road driver eye movement tracking using head-mounted devices

It is now evident from anecdotal evidence and preliminary research that distractions can hinder the task of operating a vehicle, and consequently reduce driver safety. However with increasing wireless connectivity and the portability of office devices, the vehicle of the future is visualized as an extension of the static work place - i.e. an office-on-the-move, with a phone, a fax machine and a computer all within the reach of the vehicle operator. For this research a Head mounted Eye-tracking Device (HED), is used for tracking the eye movements of a driver navigating a test route in an automobible while completing various driving tasks. Issues arising from data collection of eye movements during the completion of various driving tasks as well as the analysis of this data are discussed. Methods for collecting video and scan-path data, as well as difficulties and limitations are also reported.