Real-world Behavior Research Articles

Helping Automated Vehicles With Left-Turn Maneuvers: A Game Theory-Based Decision Framework for Conflicting Maneuvers at Intersections

The deployment of connected, automated vehicles (CAVs) provides the opportunity to enhance the safety and efficiency of transportation systems. However, despite the rapid development of this technology, human-driven vehicles are predicted to predominate the vehicle fleet, compelling CAVs to be able to operate in a mixed traffic environment. The key to achieving a reliable and safe human-CAV collaboration in such environments is to characterize the interactions between the actors and incorporate the underlying decision-making mechanism of human drivers into CAVs’ motion planning algorithms. Towards this goal and extending a previously developed game theoretical model, the present study proposes a decision-making dynamic to achieve more realistic models of human behavior when making conflicting maneuvers at intersections. A novel field test is conducted to extract the required modeling data directly from CAVs’ perception system, facilitating the incorporation of the model into CAV navigation algorithms. Model validation and sensitivity analysis provided invaluable insights into the nature of human decisions and indicated that the proposed structure is robust to environmental uncertainties and can well capture the real-world behavior of human drivers in unprotected left-turn maneuvers. The derived knowledge can be directly used in CAV motion planning algorithms to provide the vehicle with more accurate predictions of human actions when operating in mixed traffic environments.

An Extended Theory of Rational Addiction

This study extends the rational addiction theory by introducing an endogenous discounting of future utilities. The discount rate depends on habits accumulating over time because of the repeated consumption of an addictive good. The endogeneity of the discount rate affects consumption decisions via a habit-dependent rate of time preference and discloses a patience-dependence trade-off. The existence of a steady state in which habits do not grow and its optimality are proven. The local stability properties of the steady state reveal that the equilibrium can be a saddle node, implying smooth convergence to the steady state, but also a stable or unstable focus, potentially predicting real-world behaviors such as binge drinking or extreme addiction states that may drive to death. The stability of the steady state mostly depends on the habit formation process, suggesting that heterogeneity in habit formation may be a key component to explain heterogeneity in time preferences.

Calculating PFAS interfacial adsorption as a function of salt concentration using model parameters determined from chemical structure

Per- and polyfluoroalkyl substances (PFAS) are widely-detected environmental contaminants known to concentrate at surfaces and interfaces. Many of the most commonly-detected PFAS function as ionic surfactants under environmental conditions. The interfacial behaviors of ionic surfactants, including PFAS, are strongly dependent on salt concentration and composition, with interfacial affinity potentially varying by orders of magnitude for the same compound under different conditions. The work described here presents a tool for predicting the salt-dependent adsorption of PFAS compounds based entirely on chemical structure, something of great value for predicting the real-world environmental behavior of many of the large numbers of PFAS compounds for which experimental data are not available. The approach combines two different previously-developed models, one a mass-action model designed to predict the effects of salts on interfacial adsorption of ionic PFAS (the UNSW-OU salt model), and the second a group-contribution model designed to predict interfacial adsorption of PFAS in the absence of salt based on chemical structure. The challenge of combining the two models comes from the fact that both are based on different isotherms. The salt model can produce sigmoidal isotherms under salt-limited conditions (an isotherm shape that is supported by experimental evidence), while the group-contribution model can generate Langmuir parameters from calculations based on chemical structure. Equations were derived to determine salt model isotherm parameters from Langmuir parameters (either from the group-contribution model or experimental sources) by matching surface tension curves in the vicinity of the concentration of highest second derivative. Refined group-contribution model parameters were determined based on data from an additional 40 surface tension curves to allow improved structure-based predictions for important classes of PFAS that were not sufficiently well-represented in the original model. The resulting equations provide a tool allowing quantitative predictions of PFAS behavior under realistic environmental conditions for compounds for which little or no experimental data are available.

Analysing wrinkle interaction behaviour with Z-fold crease pattern in thin-film planar membrane reflector

Limited stowage volume of launch vehicles demands compact packaging of large deployable membrane structures. Employment of different folding approaches led to the unavoidable fold-lines(creases). Moreover, wrinkle reduction is essential in such thin-film solar sail and inflatable antenna structures. This article analyzes the combined effect of multiple creases and wrinkles on deployed thin Kapton’s surface accuracy. Authors have introduced a novel approach for employing membrane length shortening because of multiple creases and fold characteristics. Real-world logarithmic behaviour of crease relaxation and fold-region properties help in computing the crease curvature. A rhombus-shaped shell model with Z-folding is introduced and explored for the effect of the number of creases and their orientation. Stress concentration and wrinkle contours for applied edge tensile loading state that the fold lines affect the stress transfer path. Non-linear post-buckling analyses for the Kapton® membrane express higher wrinkle evolution in the central region over the loading edge. Besides, a discrepancy in wrinkle amplitude and wavelength reveals the effect of fold-line orientation on wrinkling. Sighting actual conditions for antenna structure, creasing profile normal to the loading direction was found preferable for maintaining reflector surface-effectiveness. Additionally, double creased membranes achieve maximum surface correctness for any angular position, as the mirror effect fold shapes reduce wrinkles the most. Results are validated by comparing with experimental outcomes.

A new paradigm for investigating real-world social behavior and its neural underpinnings.

Eye tracking and other behavioral measurements collected from patient-participants in their hospital rooms afford a unique opportunity to study natural behavior for basic and clinical translational research. We describe an immersive social and behavioral paradigm implemented in patients undergoing evaluation for surgical treatment of epilepsy, with electrodes implanted in the brain to determine the source of their seizures. Our studies entail collecting eye tracking with other behavioral and psychophysiological measurements from patient-participants during unscripted behavior, including social interactions with clinical staff, friends, and family in the hospital room. This approach affords a unique opportunity to study the neurobiology of natural social behavior, though it requires carefully addressing distinct logistical, technical, and ethical challenges. Collecting neurophysiological data synchronized to behavioral and psychophysiological measures helps us to study the relationship between behavior and physiology. Combining across these rich data sources while participants eat, read, converse with friends and family, etc., enables clinical-translational research aimed at understanding the participants' disorders and clinician-patient interactions, as well as basic research into natural, real-world behavior. We discuss data acquisition, quality control, annotation, and analysis pipelines that are required for our studies. We also discuss the clinical, logistical, and ethical and privacy considerations critical to working in the hospital setting.

Studying the Developing Brain in Real-World Contexts: Moving From Castles in the Air to Castles on the Ground.

Most current research in cognitive neuroscience uses standardized non-ecological experiments to study the developing brain. But these approaches do a poor job of mimicking the real-world, and thus can only provide a distorted picture of how cognitive operations and brain development unfold outside of the lab. Here we consider future research avenues which may lead to a better appreciation of how developing brains dynamically interact with a complex real-world environment, and how cognition develops over time. We raise several problems faced by current mainstream methods in the field, before briefly reviewing novel promising approaches that alleviate some of these issues. First, we consider research that examines perception by measuring entrainment between brain activity and temporal patterns in naturalistic stimuli. Second, we consider research that examines our ability to parse our continuous experience into discrete events, and how this ability develops over time. Third, we consider the role of children as active agents in selecting what they sample from the environment from one moment to the next. Fourth, we consider new approaches that measure how mutual influences between children and others are instantiated in suprapersonal brain networks. Finally, we discuss how we may reduce adult biases when designing developmental studies. Together, these approaches have great potential to further our understanding of how the developing brain learns to process information, and to control complex real-world behaviors.

Estimating Medication Adherence from Electronic Health Records Using Rolling Averages of Single Refill-based Estimates.

Medication adherence is usually defined as the manner in which a patient takes their medication, in relation to the regimen agreed to with their healthcare provider. Electronic Health Records (EHRs) can be used to estimate adherence in a cost-effective and non-invasive manner across large-scale populations, although there is no universally agreed optimal approach to doing so. We sought to explore patterns of asthma ICS prescription refills in a large EHR dataset, and to evaluate the use of rolling-average based measures towards short-term adherence estimation. Over 1.6 million asthma controllers were prescribed for our cohort of 91,332 individuals, between January 2009 and March 2017. The Continuous Single interval measures of medication Availability (CSA) and Gaps (CSG) were calculated for individual prescriptions, as well as rolling-average adherence measures of the CSA over 3, 5, or 10 past prescription intervals. 16.7% of the study population had only a single prescription during their follow-up (a median duration of 7.1 years). 51% of prescriptions were refilled before (or on the day that) supply was exhausted, and for 19% of prescription refills, the amount of medication dispensed should have lasted at least twice as long as the duration before the next refill was filled. The rolling average measures had statistically strong associations (Spearman |R|>0.7) with the estimate for the subsequent prescription refill. Rolling averages of multiple individual refill-level adherence estimates provide a novel and simple way to crudely smoothen estimates from individual prescription refills, which are strongly influenced by common (and adherent) real-world behaviors, for more meaningful and effective trend detection. Clinical Relevance- This demonstrates a novel methodology for estimating medication adherence which can detect recent changes in trends.

Image features influence reaction time

We aim to ask and answer an essential question " how quickly do we react after observing a displayed visual target?" To this end, we present psychophysical studies that characterize the remarkable disconnect between human saccadic behaviors and spatial visual acuity. Building on the results of our studies, we develop a perceptual model to predict temporal gaze behavior, particularly saccadic latency, as a function of the statistics of a displayed image. Specifically, we implement a neurologically-inspired probabilistic model that mimics the accumulation of confidence that leads to a perceptual decision. We validate our model with a series of objective measurements and user studies using an eye-tracked VR display. The results demonstrate that our model prediction is in statistical alignment with real-world human behavior. Further, we establish that many sub-threshold image modifications commonly introduced in graphics pipelines may significantly alter human reaction timing, even if the differences are visually undetectable. Finally, we show that our model can serve as a metric to predict and alter reaction latency of users in interactive computer graphics applications, thus may improve gaze-contingent rendering, design of virtual experiences, and player performance in e-sports. We illustrate this with two examples: estimating competition fairness in a video game with two different team colors, and tuning display viewing distance to minimize player reaction time.

Quantifying navigation complexity in transportation networks.

The complexity of navigation in cities has increased with the expansion of urban areas, creating challenging transportation problems that drive many studies on the navigability of networks. However, due to the lack of individual mobility data, large-scale empirical analysis of the wayfinder's real-world navigation is rare. Here, using 225 million subway trips from three major cities in China, we quantify navigation difficulty from an information perspective. Our results reveal that (1) people conserve a small number of repeatedly used routes and (2) the navigation information in the subnetworks formed by those routes is much smaller than the theoretical value in the global network, suggesting that the decision cost for actual trips is significantly smaller than the theoretical upper limit found in previous studies. By modeling routing behaviors in growing networks, we show that while the global network becomes difficult to navigate, navigability can be improved in subnetworks. We further present a universal linear relationship between the empirical and theoretical search information, which allows the two metrics to predict each other. Our findings demonstrate how large-scale observations can quantify real-world navigation behaviors and aid in evaluating transportation planning.

Layout optimization of long-span structures subject to self-weight and multiple load-cases

Layout optimization provides a powerful means of identifying materially efficient structures. It has the potential to be particularly valuable when long-span structures are involved, since self-weight represents a significant proportion of the overall loading. However, previously proposed numerical layout optimization methods neglect or make non-conservative approximations in their modelling of self-weight and/or multiple load-cases. Combining these effects presents challenges that are not encountered when they are considered separately. In this paper, three formulations are presented to address this. One formulation makes use of equal stress catenary elements, whilst the other two make use of elements with bending resistance. Strengths and weaknesses of each formulation are discussed. Finally, an approach that combines formulations is proposed to more closely model real-world behaviour and to reduce computational expense. The efficacy of this approach is demonstrated through application to a number of 2D- and 3D-structural design problems.

Characterizing driver speeding behavior when using partial-automation in real-world driving

Objective: Speeding is a prevalent and complex risky behavior that can be affected by many factors. Understanding how drivers speed is important for developing countermeasures, especially as new automation features emerge. The current study seeks to identify and describe types of real-world speeding behaviors with and without the use of partial-automation. Methods: This study used a combination of supervised and unsupervised data analysis techniques to assess relevant factors in real-world speeding epochs, extracted from the MIT Advanced Vehicle Technology Naturalistic Driving Study, and classified them into distinct speeding behaviors. Speeding epochs were defined as traveling at least 5 mph over the speed limit for a minimum duration of 3 s. Vehicle speed-exceedance profiles were characterized over time using Dynamic Time Warping and included in multivariate models that evaluated the associations between different features of the speeding epochs, such as speeding duration and magnitude. Finally, the identified features were used to cluster speeding behaviors using the Gower dissimilarity measure. Results: The analysis yielded four types of behaviors in both partially-automated and manual driving: (i) Incidental speeding (low duration, low magnitude), (ii) Moderate speeding (low duration, moderate magnitude), (iii) Elevated speeding (moderate duration, high magnitude), and (iv) Extended speeding (long duration, high magnitude). When comparing the behaviors with and without partial-automation use, both Incidental and Moderate speeding were found to have significantly longer durations with partial-automation than manual driving. Elevated speeding was found to be more prevalent and associated with higher magnitudes during manual than with partially-automated driving. Finally, although Extended speeding was more prevalent during automation use, it was associated with a lower mean and maximum speed magnitude compared to Extended speeding during manual driving. Conclusions: This work highlights the variability in speeding behavior between and within partially-automated and manual driving. The design of systems that mitigate risky speeding behaviors should consider targeting divergent behaviors observed between manual and automated driving as a mechanism to mitigate the prevalence of the different behaviors associated with each state.

Validation of Agent-Based Passenger Movement Modeling for Railway Stations Subject to Social Distancing During the COVID-19 Pandemic

The COVID-19 pandemic has caused unprecedented difficulties keeping passenger transport running while social distancing has constrained pedestrian movement. To support railway operation an agent-based simulation validated against UK mainline railway station CCTV footage has been developed. The simulation quantifies train alighting- and boarding flow times for different degrees of distancing, rolling stock types, platform size, and passenger numbers. Real-world social distancing behavior was represented, including compromises people make on distancing to achieve their goals. Flow times modeled and those measured from CCTV were within 10%. Relative to a baseline without social distancing, 1-m distancing was predicted to make only a marginal difference to passenger flow times, primarily because of passenger behavior to compromise on distancing at the rate determining door location. For 2-m social distancing, significantly extended passenger alighting and boarding flow times were predicted for busier services (i.e., 2.2 to 2.8 times baseline depending on rolling stock type). These increases in flow time are only predicted to begin when the combined total of boarding and alighting passengers exceeds 10 to 15 per door. The model has applications in transport systems worldwide in avoiding unmaintainable timetables, and in reducing incentives for social distancing compromise when distancing forms a component of suppressing virus transmission.

Sensory Evidence Accumulation Using Optic Flow in a Naturalistic Navigation Task.

Sensory evidence accumulation is considered a hallmark of decision-making in noisy environments. Integration of sensory inputs has been traditionally studied using passive stimuli, segregating perception from action. Lessons learned from this approach, however, may not generalize to ethological behaviors like navigation, where there is an active interplay between perception and action. We designed a sensory-based sequential decision task in virtual reality in which humans and monkeys navigated to a memorized location by integrating optic flow generated by their own joystick movements. A major challenge in such closed-loop tasks is that subjects' actions will determine future sensory input, causing ambiguity about whether they rely on sensory input rather than expectations based solely on a learned model of the dynamics. To test whether subjects integrated optic flow over time, we used three independent experimental manipulations, unpredictable optic flow perturbations, which pushed subjects off their trajectory; gain manipulation of the joystick controller, which changed the consequences of actions; and manipulation of the optic flow density, which changed the information borne by sensory evidence. Our results suggest that both macaques (male) and humans (female/male) relied heavily on optic flow, thereby demonstrating a critical role for sensory evidence accumulation during naturalistic action-perception closed-loop tasks.SIGNIFICANCE STATEMENT The temporal integration of evidence is a fundamental component of mammalian intelligence. Yet, it has traditionally been studied using experimental paradigms that fail to capture the closed-loop interaction between actions and sensations inherent in real-world continuous behaviors. These conventional paradigms use binary decision tasks and passive stimuli with statistics that remain stationary over time. Instead, we developed a naturalistic visuomotor visual navigation paradigm that mimics the causal structure of real-world sensorimotor interactions and probed the extent to which participants integrate sensory evidence by adding task manipulations that reveal complementary aspects of the computation.

Step forward in epidemiological modeling: Introducing the rate indicator function to capture waves

In the last centuries, mathematical models have been used to depict the dynamic evolution of infectious diseases’ spread. The aim is to determine the total numbers of infected, recovered, and susceptible individuals; however, they only represent accumulated values due to the complexities of collected data. Having the graphical representations of these classes as accumulated values, one may not directly be able to predict waves to determine a day-to-day number of newly infected cases as some additional calculations are required. Collected data from real-world situations are represented as day-to-day new infections; they help determine in addition numbers of waves. However, current existing mathematical models cannot be used for wave prediction. While knowing the predicted numbers of waves, policymakers can take adequate measures to control the situation. To solve this problem, we questioned the fact that the rates of infection and recovery are constant and suggested an indicator rate function obtained using experimental data. To see the effect of this function, we considered a simple SIR model, which was modified by introducing rate indicator functions for infected and recovered classes. To include nonlocal behaviors in the mathematical model, different types of differential operators, including classical and fractional derivatives, were used. The models were solved numerically using well-known numerical schemes. The numerical solutions were plotted for different theoretical parameters; the results depict real-world behaviors. To test the efficiency of this new approach, we collected data from South Africa and compared them with our model. Not only our model could predict waves, but also it fits experimental data very accurately. This new approach will open new doors of investigation toward a revolution in epidemiological modeling.

Advancements on bifurcation behavior and operational deflection shapes of disk brake creep groan

Disk brake creep groan vibrations are friction-induced stick–slip vibrations. Their impulse-like excitation, caused by the physical properties of the frictional contacts, leads to strongly nonlinear vibrations of brake system, axle and also chassis parts. As with many nonlinear phenomena, theoretical and experimental investigations on the bifurcation behavior were already done. So-far performed experiments used either strongly reduced setups or were limited in the controllability of testing, leading to certain deviations and a reduced complexity compared to the real-world behavior of the full vehicle. In this work, an approach based on half-axle tests is presented. Here, tire and rim are part of the system. By running drum-driven test matrices, extended stability maps of the rest position were created. An operational deflection shape (ODS) analysis over all 72 operating points of the test matrix was performed. Together with the relative speeds in the friction contact, a novel classification of creep groan phenomena is presented. These results prove an interaction between longitudinal and rotational axle displacements during creep groan, which was already assumed in corresponding vehicle tests. The insights enable a clearer distinction of creep groan, which is necessary for the accurate objective rating of creep groan phenomena in industry. Furthermore, the ODS results suggest the structure for a sufficient minimal model.

Measuring Ostracism-Induced Changes in Consumption of Palatable Food: Feasibility of a Novel Behavioral Task

PurposeOstracism is a highly aversive interpersonal experience. Previous research suggests that it can increase consumption of highly palatable food in some individuals, but decrease it in others. Thus, we developed the Cyberball-Milkshake Task (CMT), to facilitate research investigating individual differences in ostracism’s effects on consumption of highly palatable food. We present data on feasibility for the CMT in a sample of young adult women.Materials and MethodsParticipants were 22 women, 18–30 years old, reporting very low or very high levels of emotional eating at screening. Participants performed the CMT, which consisted of 12 trials. Each trial included: playing a round of Cyberball (a computerized game of catch with fictitious “other participants” programmed to either include or exclude the participant); viewing a chocolate image; and then consuming a participant-determined amount of milkshake. Participants subsequently played an additional inclusion and exclusion round of Cyberball, each immediately followed by questionnaires assessing current mood and recent Cyberball experience.ResultsCyberball exclusion (vs. inclusion) was associated with large, significant increases in reported ostracism and threats to self-esteem; exclusion’s effects on affect were in the expected direction (e.g., increased negative affect), but generally small and non-significant. Milkshake intake was measurable for 95% of participants, on 96% of trials. Intake decreased quadratically across trials, with a steep negative slope for low trial numbers that decreased to the point of being flat for the highest trial numbers.DiscussionThe CMT is a generally feasible approach to investigating ostracism’s effects on consumption of highly palatable food. The feasibility (and validity) of the CMT may benefit from modification (e.g., fewer trials and longer rounds of Cyberball). Future research should examine whether performance on a modified version of the CMT predicts real-world behavior in a larger sample.

Restraint Use for Child Occupants in Dubai, United Arab Emirates.

The overall objective of the current study was to investigate the behaviours and knowledge of parents/carers in relation to safe child occupant travel in the Emirate of Dubai in the United Arab Emirates (UAE). A community survey was completed by 786 participants who were responsible for the safety of 1614 children (aged 10 years and younger). The survey included questions related to the type, frequency and appropriateness of restraint use for their eldest child. Overall, 24 percent of participants reported that they ‘never/almost never’ restrained their eldest child while travelling in a motor vehicle, with this proportion increasing with child age. For example, though 89 percent of participants reported that they restrained their infants (<1 year) in an ‘appropriate’ restraint for their age, this rate was much lower for children aged between 5 and 7 years (10%). Overall, these findings suggest that a large proportion of child occupants, especially those aged five years and older, are not appropriately restrained in vehicles, and therefore are at an increased risk of death or serious injury in the event of a crash. Future research will validate this self-reported child restraint use data with objective data from observations of real-world child restraint use behaviour in the UAE.

Family accommodation in pediatric anxiety: Relations with avoidance and self-efficacy

Pediatric anxiety disorders are common, impairing, and chronic when not effectively treated. A growing body of research implicates family accommodation in the maintenance of pediatric anxiety. The present study aimed to quantify previously untested relations among family accommodation and two theoretically linked constructs: avoidance and self-efficacy. Eighty youths between ages 8 and 17 (53 with anxiety disorders, 27 non-anxious controls) completed measures of family accommodation and self-efficacy. In addition, avoidance was assessed using two distinct measures of avoidance: a clinician rating of real-world behaviors and a laboratory task-based index. As predicted, youths with anxiety disorders reported greater family accommodation than non-anxious controls. Across the sample, greater family accommodation was associated with greater avoidance, as measured using both clinician rating and the laboratory task, as well as with lower self-efficacy. In an exploratory mediation model, self-efficacy partially mediated the relation between family accommodation and clinician-rated avoidance; however, it did not mediate the relation between family accommodation and task-based avoidance. Considering the robust association between family accommodation and anxiety in youths, this addition to our understanding of related cognitive and behavioral factors provides important preliminary insight, which can guide future research on potential targets for early identification and intervention for pediatric anxiety.

Defining American National Identity: An Exploration into Measurement and Its Outcomes

AbstractScholars of American identity have typically concluded that Americans more widely endorse civic values than ascriptive ones in surveys, though IATs suggest that there are robust associations between race and American identity. In addition to this apparent contradiction, these studies share similar methodological limitations: the discrepancy between reported attitudes and real-world behavior. Though these methods are well-cited in the wider literature, attitudes are often conflated to be synonymous with behavior in American identity scholarship. I argue that it is necessary to study how Americans conceive of their national identity in different situational contexts. Using the complementary techniques of semi-structured interviewing and qualitative vignettes, I explore and compare the ways in which 10 American graduate students make sense of their national identity in a series of abstract and concrete settings. Results of a multi-method text analysis approach demonstrate that: 1) there are a multitude of components not currently being discussed or measured; 2) the invocation of American identity components depends on their setting; 3) the ways in which components are characterized are just as important as their invocation; and 4) the difficulty expressed by participants to define a singular American identity underscores the continued salience of the multiple traditions thesis.

Anti-corrosion, anti-bacterial and durable atmospheric weatherability of polydimethylsiloxane coating with intrinsic hydrophobicity

Understanding the corrosion resistance, microorganism suppression and real-world weatherability and application potentiality of intrinsically hydrophobic polydimethylsiloxane (PDMS) coating is of great significance for developing multi-functional composite protective materials. In this paper, a pure PDMS coating was prepared through spray-coating technique on Q235 carbon steel. The surface morphologies, wettability, chemical compositions, corrosion resistance, bacteria adhesion and real-world atmospheric durability behaviors were investigated. The electrochemical assessment results show that the PDMS-coated Q235 carbon steel exhibits greatly enhanced charge transfer resistance (R ct), positive movement of corrosion potential (E corr), and extremely low corrosion current density (I corr). Besides, the PDMS coating presents high anti-bacterial efficiency against Escherichia coli and Pseudomonas sp. adhesion. The real-world atmospheric weatherability, salt spray and abrasion resistance reveal that the PDMS coating can be considered as a superior and durable barrier against marine corrosion and biofouling invasion.