Assessing the driving distraction effect of vehicle HMI displays using data mining techniques

With the rapid development of human–machine interface (HMI) systems in vehicles, driving distraction caused by HMI displays affects road safety. This study presents a data mining technique to model the four driving distraction indicators: speed deviation, lane departure standard deviation, dwell time, and mean glance time. Driving distraction data was collected on a real-car driving simulator. 3 secondary tasks in 13 mass produced cars were tested by 24 drivers. The random forest algorithm outperformed linear regression, extreme gradient boosting, and multi-layer perceptron as the best model, demonstrating good regression performance as well as good interpretability. The result of random forest showed that the importance of target speed is large for all driving distraction indicators. Among the variables of interaction and user interface design, less step and less on-screen distance of finger movement are efficient for lowering lane departure standard deviation and dwell time. The position of right point is another important variable, and should be between 37 and 47 degrees on a typical sample in this study. A larger angle leads to bigger lane departure, while a smaller angle leads to bigger mean glance time. Most variables of HMI display positioning themselves are not important. This study provides one driving distraction assessment method with a variable impact trend analysis for HMI secondary tasks in an early phase of product development.     

Relation of age and passive properties of an ankle dorsiflexion stretch to the timed one-leg stance test in older women

26 older women (aged 65 to 89 years) participated in this study, which examined the relationship of age and passive properties of a dorsiflexion stretch of the calf muscle-tendon unit with one-leg stance times. Age was negatively correlated with the time stance (r = -.75). The maximal passive dorsiflexion angle, length extensibility, maximal passive dorsiflexion torque, and the area under the passive curve (total passive elastic energy) were all positively correlated with the stance time (range: r = .49-.69). A multiple regression analysis indicated age was the best predictor of the times. Age and the maximal passive dorsiflexion angle together accounting for 71% of the variance in the time (R = .84, R(2) = .71). The addition of the remaining passive measurements did not improve the variance accounted for in the one-leg stance time. The results indicated that the maximal ankle dorsiflexion range of motion may be important for one-leg standing balance of older women. Accordingly, stretching exercises designed to increase the maximal dorsiflexion angle may have a role for maintaining or improving their standing balance.     

Range Shrinkage of Cognitive Ability Test Scores in Applicant Pools for German Governmental Jobs: Implications for range restriction corrections

Range restriction corrections require the predictor standard deviation in the applicant pool of interest. Unfortunately, this information is frequently not available in applied contexts. The common strategy in this type of situations is to use national‐norm standard deviation estimates. This study used data from 8,276 applicants applying to nine jobs in German governmental organizations to compare applicant pool standard deviations for two cognitive ability tests with national‐norm standard deviation estimates, and standard deviations for the total group of governmental applicants. Results revealed that job‐ and organizational context‐specific applicant pool standard deviations were on average about 10–12% smaller than estimates from national norms, and about 4–6% smaller than standard deviations for the total group of governmental applicants.     

Rest position of the eyes and its effect on viewing distance and visual fatigue in computer display work

A deviation between the angle of convergence during visual work and the resting level of the vergence system (vergence discrepancy) should be associated with costs; subjects should tend to reduce these costs by increasing the observation distance. The remaining costs should contribute to visual fatigue. Both hypotheses were tested using a sample of 40 subjects, mainly students. In agreement with the first hypothesis, subjects with large initial vergence discrepancy increased their observation distance more in the course of 1 1/2 hours of visual work than subjects with smaller initial vergence discrepancy. Visual fatigue was assessed using a set of questions developed in two pilot studies. Contrary to the second hypothesis, visual fatigue did not depend on effective vergence discrepancy, that is, the deviation between the resting level of the vergence system and the actual angle of convergence. In addition, such a relationship was not found for further dependent variables (performance, BMS questionnaire, critical flicker frequency, evaluation of conditions of work, postural complaints). The results are discussed with respect to the role of tonic and dynamic components of the vergence system for visual fatigue.     

Analysis of vehicle-based lateral performance measures during distracted driving due to phone use

Distracted driving due to mobile phone use has been identified as a major contributor to accidents; therefore, it is required to develop ways for detecting driver distraction due to phone use. Though prior literature has documented various visual behavioural and physiological techniques to identify driver distraction, comparatively little is known about vehicle based performance features which can identify driver’s distracted state during phone conversation and texting while driving. Therefore, this study examined the effects of simple conversation, complex conversation, simple texting and complex texting tasks on vehicle based performance parameters such as standard deviation of lane positioning, number of lane excursions, mean and standard deviation of lateral acceleration, mean and standard deviation of steering wheel angle and steering reversal rates (for 1°, 5° and 10° angle differences). All these performance measures were collected for 100 licensed drivers, belonging to three age groups (young, mid-age and old age), with the help of a driving simulator. Effects of all the phone use conditions and driver demographics (age, gender and phone use habits) on the measures were analysed by repeated measures ANOVA tests. Results showed that 1°, 5° SRRs are able to identify all the distracted conditions except for simple conversation; while, 10° SSR can detect all the distracted conditions (including simple conversation). The results suggest that 10° SRR can be included in intelligent in-vehicle devices in order to detect distraction and alert drivers of their distracted state. This can prevent mobile phone use during driving and therefore can help in reducing the road accidents due to mobile phone distractions.     

Age-related changes in temporal resolution: envelope and intensity effects.

Gap-detection thresholds were determined for 10 younger and 10 older adults at two sensation levels (40 and 60 dB SL) for tone pips with Gaussian amplitude envelopes whose standard deviations were 0.5, 1, 1.5, and 2 ms. Gap-detection thresholds were larger for the older participants under all conditions. For all participants, gap-detection thresholds increased with the standard deviation of the Gaussian amplitude envelope, were relatively independent of sensation level, and were independent of the degree of hearing loss. Because spectral splatter decreases with increasing standard deviation of the Gaussian amplitude envelope, the age-related differences in gap-detection cannot be attributed to differences between how young and old listeners are affected by off-frequency cues. Furthermore, the consistent age difference in gap-detection at all amplitude envelope standard deviations was shown to be incompatible with the hypothesis that temporal integration time is longer for older listeners.     

Directional variability of the isometric force vector produced by the human hand in multijoint planar tasks

Numerous studies have examined control of force magnitude, but relatively little research has considered force direction control. The subjects applied isometric forces to a handle and the authors compared within-trial variability when force is produced in different directions. The standard deviation of the force parallel to the prescribed direction of force production increased linearly with the targeted force level, as did the standard deviation of the force perpendicular to the instructed direction. In contrast, the standard deviation of the angle of force production decreased with increased force level. In the 4 (of 8) instructed force directions where the endpoint force was generated due to a joint torque in only 1 joint (either the shoulder or elbow) the principal component axes in force space were well aligned with the prescribed direction of force production. In the other directions, the variance was approximately equal along the 2 force axes. The variance explained by the first principal component was significantly larger in torque space compared to the force space, and mostly corresponded to positive correlation between the joint torques. Such coordinated changes suggest that the torque variability was mainly due to the variability of the common drive to the muscles serving 2 joints, although this statement needs to be supported by direct studies of muscle activation in the future.     

Directional Variability of the Isometric Force Vector Produced by the Human Hand in Multijoint Planar Tasks

Numerous studies have examined control of force magnitude, but relatively little research has considered force direction control. The subjects applied isometric forces to a handle and the authors compared within-trial variability when force is produced in different directions. The standard deviation of the force parallel to the prescribed direction of force production increased linearly with the targeted force level, as did the standard deviation of the force perpendicular to the instructed direction. In contrast, the standard deviation of the angle of force production decreased with increased force level. In the 4 (of 8) instructed force directions where the endpoint force was generated due to a joint torque in only 1 joint (either the shoulder or elbow) the principal component axes in force space were well aligned with the prescribed direction of force production. In the other directions, the variance was approximately equal along the 2 force axes. The variance explained by the first principal component was significantly larger in torque space compared to the force space, and mostly corresponded to positive correlation between the joint torques. Such coordinated changes suggest that the torque variability was mainly due to the variability of the common drive to the muscles serving 2 joints, although this statement needs to be supported by direct studies of muscle activation in the future.     

Accuracy and precision of the PEAK Performance Technologies Motion Measurement System

This study evaluated the accuracy and precision of the PEAK Performance Technologies, lnc.'s motion analysis system for three-dimensional angle reconstruction. Pendular motion of a bar, on which 18 retroreflective markers were mounted, was videotaped at three different orientations (parallel, and rotated 30 degrees right and left) to a plane at which two standard video cameras were aimed. The videotaped motion was digitized off-line, and 32 angles between the 18 markers were calculated. intraclass correlation coefficients (ICCs) were calculated between trials within each pendulum orientation and across orientations to determine system precision, and between randomly selected trials and actual angles to determine accuracy. lCCs were in all cases greater than.99. Within-trial standard deviations ranged between 0.05-0.8 degrees for the different angles. Deviations from the actual angle averaged 0.0-0.8 degrees across all angles and orientations. The results indicate that accurate and reliable angular measurements can be made with this motion analysis system.     

Information–Movement Coupling in The Control of Driver Approach to an Intersection

We characterized the control mechanisms underlying crossing an intersection with vehicular traffic. Specifically, we identified potential markers of the coupling between information and movement through a kinematic analysis of the approach. We exposed participants in a driving simulator experiment to several scenarios. We manipulated task constraints by varying the acceleration capabilities of the vehicle and the time available to make speed adjustments. The results highlighted gradual, systematic adjustments, which make it possible to cross the intersection in a zone that is close to the center of the intervehicular gap. The functional nature of these adjustments was highlighted by concomitant and opposite variation in the variability of current speed and current deviation. In all cases, an increase in the standard deviation of speed was accompanied by a reduction in the standard deviation of current deviation. Neither time to make adjustments nor acceleration capabilities modified the observed kinematic patterns, but they did modulate the adjustments that were produced. Overall, these results were consistent with a control mechanism based on the implementation of an information–movement cycle.     

Vertical force and wrist deviation angle when using a walker to stand up and sit down

Research investigating walkers suggests that safety and assistance for the elderly with weak lower limbs were important. However, the relationship between the use of a walker and the upper limbs has received little investigation. Standing up and sitting down are important daily activities. Therefore, the aim of this study was to explore wrist deviation and vertical force among elderly individuals using a walker for assistance to stand up and sit down. In total, 64 elderly volunteers (M age = 80.22, SD = 9.36) were enrolled. Data were obtained from four load cells and a twin-axis wrist goniometer. Wrist deviation and vertical force were examined when participants used a walker with horizontal handles to assist in standing up and sitting down. Significant wrist angle deviation occurred with the use of a walker, with dorsiflexion of the right hand greater than that of the left. Males exerted significantly greater vertical force. In the sitting position, greater ulnar deviation was seen among experienced walker users, whereas during standing, experienced users exhibited greater dorsiflexion. The horizontal handles of most marketed walkers may cause user wrist deviations, suggesting researchers should pursue improvements in walker design.     

Stability and variability may respond differently to changes in walking speed

In gait research it has often been assumed that variability and stability are negatively correlated, where increases in variability are assumed to equate with increases in instability. The purpose of this paper is to illustrate that variability does not always equate with stability. To proof this point, a method was developed to directly assess stability and variability during the application of a visual perturbation at different walking speeds. Walking variability was measured by using the average standard deviation of the knee joint angle across the gait cycle. Walking stability was measured by the recovery time of the knee joint angle trajectory from the distortion induced by a visual perturbation that was delivered at the beginning of the stance phase. Five participants were required to walk at six different velocities on a treadmill (0.67, 0.80, 0.94, 1.07, 1.21, and 1.34 m/s). The coefficients of intraclass correlations for the experiment were 83% and 80% for the calculated stability and variability, respectively. The calculated stabilities were not sensitive to changes in walking speed (p>0.98). The calculated variability however decreased with increases in walking speed (p=0.004). No significant correlation between variability and stability was observed (r=-0.002). We suggest that gait stability is independent of variability during locomotion and should thus be measured independently.     

Memorizing while walking: increase in dual-task costs from young adulthood to old age

The dual task of memorizing word lists while walking was predicted to become more difficult with age because balance and gait are in greater need of "attentional resources." Forty-seven young (ages 20-30 years), 45 middle-aged (40-50), and 48 old (60-70) adults were trained to criterion in a mnemonic technique and instructed to walk quickly and accurately on 2 narrow tracks of different path complexity. Then. participants encoded the word lists while sitting, standing, or walking on either track; likewise, speed and accuracy of walking performance were assessed with and without concurrent memory encoding. Dual-task costs increased with age in both domains; relative to young adults, the effect size of the overall increase was 0.98 standard deviation units for middle-aged and 1.47 standard deviation units for old adults. It is argued that sensory and motor aspects of behavior are increasingly in need of cognitive control with advancing age.     

A system for recording individualized behavioral data in a token program

A data matrix system used to record and summarize individual behavioral data is described. The major characteristics of the system are: (1) it provides a place to record and summarize all patient token exchanges, whether for standard contingencies or for idiosyncratic behavior; (2) it serves as a record and summary for time samples observed during a 24-hr period and as a record of reliability data on time sample measures; (3) it provides a place where the new token balance for each patient can be calculated and recorded for use the next day; (4) it provides for calculation of an individual patient's token balance at any given moment; and (5) it is a permanent record of each patient's daily participation in the program and documents progress in terms of his economic status as well as in changes in critical target behaviors.     

Multifractal roots of suprapostural dexterity

Visually guided postural control emerges in response to task constraints. Task constraints generate physiological fluctuations that foster the exploration of available sensory information at many scales. Temporally correlated fluctuations quantified using fractal and multifractal metrics have been shown to carry perceptual information across the body. The risk of temporally correlated fluctuations is that stable sway appears to depend on a healthy balance of standard deviation (SD): too much or too little SD entails destabilization of posture. This study presses on the visual guidance of posture by prompting participants to quietly stand and fixate at distances within, less than, and beyond comfortable viewing distance. Manipulations of the visual precision demands associated with fixating nearer and farther than comfortable viewing distance reveals an adaptive relationship between SD and temporal correlations in postural fluctuations. Changing the viewing distance of the fixation target shows that increases in temporal correlations and SD predict subsequent reductions in each other. These findings indicate that the balance of SD within stable bounds may depend on a tendency for temporal correlations to self-correct across time. Notably, these relationships became stronger with greater distance from the most comfortable viewing and reaching distance, suggesting that this self-correcting relationship allows the visual layout to press the postural system into a poise for engaging with objects and events. Incorporating multifractal analysis showed that all effects attributable to monofractal evidence were better attributed to multifractal evidence of nonlinear interactions across scales. These results offer a glimpse of how current nonlinear dynamical models of self-correction may play out in biological goal-oriented behavior. We interpret these findings as part of the growing evidence that multifractal nonlinearity is a modeling strategy that resonates strongly with ecological-psychological approaches to perception and action.     

Microreaction timer

A small unprepared simple reaction time (RT) system is described in which the visual stimuli are presented at quasi-random intervals of 3–13 sec. The device is battery-portable for administration in the field and for immediate presentation of mean RT and standard deviation after the test. These data plus all individual RTs are stored in digital memory for printout or further analysis in the laboratory. Up to 24 10-min tests may be accumulated in memory.     

Attention during visual secondary tasks in driving: Adaptation to the demands of the driving task

Visual attention in driving with visual secondary task is compared for two visual secondary tasks. N = 40 subjects completed a 1 h test drive in a motion-base driving simulator. During the drive, participants either solved an externally paced, highly demanding visual task or a self paced menu system task. The secondary tasks were offered in defined critical and non-critical driving situations. Eye movement behavior was analyzed and compared for both tasks. Before starting the secondary tasks, eye movement behavior shows a smaller standard deviation of gaze as well as longer fixation durations for both tasks. The comparison between the two tasks indicates that drivers use the possibilities the self paced task offers: during the secondary task, they monitor the driving scene with longer fixations and show a greater standard deviation of gaze position. Furthermore, independently of the type of secondary task, drivers adapt their eye movement behavior to the demands of the situation. In critical driving situations they direct a larger proportion of glance time to the driving task. Last, the relation between glance behavior and collisions is analyzed. Results indicate that collisions go together with an inadequate distribution of attention during distraction. The results are interpreted regarding the attentional processes involved in driving with visual secondary tasks. Based on the similarities and differences between the two secondary tasks, a cognitive approach is developed which assumes that the control of attention during distraction is based on a mental situational model of the driving situation.     

Intra-individual stability of neuromotor tasks from 6 to 18 years: a longitudinal study

This study investigates the intra-individual stability of the speed of several motor tasks and the intensity of associated movements in 256 children (131 girls, 125 boys) from the Zurich generational study using the Zurich neuromotor assessment battery (ZNA) over a 12-year period from the age of 6 to 18 years. The stability was assessed by correlograms of standard deviation scores calculated from age- and gender-adjusted normative values and compared with standing height and full scale intelligence quotient (IQ). While motor tasks of hand, finger and foot (HFT) and contralateral associated movements (CAM) exhibited a moderate stability (summary measure as correlation coefficients between two measurements made 4 years apart: .61 and .60), other tasks (dynamic balance, static balance and pegboard) were only weakly stable (.46, .47 and .49). IQ and height were more stable than neuromotor components (.72 and .86). We conclude that the moderately stable HFT and CAM may reflect “motor traits”, while the stability of the pegboard and balance tasks is weaker because these skills are more experience related and state-dependent.     

Semantic control of eye movements in picture scanning during sentence-picture verification

The Weber fraction, (I + Δ)/I, was measured for pure tones which were I presented either homophasically or antiphasically. For both stimuli, the Weber fraction was measured as a function of changes in the level of the standard tone Iand in the phase angle of addition between a test tone and the standard tone. The value, ΔI, in the Weber fraction was defined as that difference between the level of the test-plus-standard and the level of the standard (I) which was required for the listener to discriminate a difference between the standard and the test-plus-standard. In the homophasic case, the Weber fraction remained constant for changes in the phase angle of addition, whereas in the antiphasic condition, the Weber fraction decreased for increasing values of the phase angle of addition. For both the homophasic and antiphasic conditions and at all values of the phase angle of addition, the Weber fraction remained a constant as the value of the standard was varied. These results are in agreement with those obtained in studies involving noise masking, lateralization, and the monaural Weber fraction.