114612 research outputs found
Sort by
Extending scenario description languages for intelligence testing of autonomous vehicles
No full textScenario-based verification and validation (V&V) has emerged as the predominant approach for the performance evaluation of autonomous vehicles (AV). Many scenariogeneration methods have been proposed to search for critical scenarios, i.e. disengagement or traffic rule violations. However, the widely adopted binary (pass/fail) criterion suffers from two main limitations, i.e., the difficulty of locating root causes and the lack of statistical guarantee of testing sufficiency. Recently, new scenario engineering approaches focusing on the intelligence of autonomous vehicles enlightened a promising pathway via dynamic driving task decomposition and function atom constraints. However, none of the state-of-the-art scenario description languages support such approaches. To fill this gap and facilitate further research into this promising direction, in this work, we propose a generic architecture to extend the existing scenario description languages for the intelligence testing of autonomous vehicles. The case study with WMG SDL demonstrates the capability and flexibility of the proposed extension design in defining intelligence function constraints
Hard congestion limit of the dissipative Aw–Rascle system
Get PDFIn this study, we analyse the famous Aw–Rascle system in which the difference between the actual and the desired velocities (the offset function) is a gradient of a singular function of the density. This leads to a dissipation in the momentum equation which vanishes when the density is zero. The resulting system of PDEs can be used to model traffic or suspension flows in one dimension with the maximal packing constraint taken into account. After proving the global existence of smooth solutions, we study the so-called 'hard congestion limit', and show the convergence of a subsequence of solutions towards a weak solution of a hybrid free-congested system. This is also illustrated numerically using a numerical scheme proposed for the model studied. In the context of suspension flows, this limit can be seen as the transition from a suspension regime, driven by lubrication forces, towards a granular regime, driven by the contacts between the grains
Applying event system theory to organizational change : the importance of everyday positive and negative events
Get PDFDecades of research have examined how employees experience organizational-level change events (e.g., “the merger”). However, employees can also experience “everyday change events” that occur at the individual-level as the change becomes routinized for their jobs. That is, individuals can react to organizational change events that are occurring at different hierarchical levels. Drawing on event system theory, we argue that employees’ commitment to the organizational-level change event can shape how employees anticipate and experience subsequent everyday change events. These negative and positive everyday change events can impact (a) how employees engage with their work, impacting their performance and (b) whether employees perceive that they are fairly treated, impacting their subsequent evaluations of organizational-level change. Our hypotheses were generally supported in a field sample in which employees were surveyed immediately after a merger was announced, participated in a daily diary study as the merger was implemented, and completed a second survey 2 weeks after the diary study. By applying event system theory to organizational change, we provide important theoretical and practical insights, including how an organizational-level event can exert top-down direct effects by impacting how employees anticipate and experience change on an everyday basis as well as how everyday negative and positive change events can subsequently impact employees’ commitment to the organizational-level change, creating bottom-up direct effects. We also illuminate the importance of considering the frequency and strength of both negative and positive events to understand what it is about everyday negative and positive events that has implications for employees and organizations
Red herrings : a model of attention-hijacking by politicians
Get PDFPoliticians often use “red herrings” to distract voters from scandals. When do such red herrings succeed? I develop a model in which an incumbent runs for re-election and potentially faces a scandal. Some incumbents enjoy telling “tales” (attention-grabbing stories) while others use tales to distract voters from the scandal. Multiple equilibria can arise: one with a norm of tale-telling in which red herrings succeed and another with a norm against tale-telling in which they fail. Increased media attention to tales has a nonmonotonic effect, facilitating red herrings at low attention levels, but serving a disciplinary function at high levels
Childhood parental bonding and depression in adulthood : a study of mothers in rural Pakistan
No full textBackground
Parent-child relationship quality can have long-term impacts on child mental health into adulthood. The impact of parental behaviors on the future mental health of children has been understudied in South Asia, where parenting approaches differ from the dominant western approaches often represented in the literature.
Methods
Mothers in rural Pakistan (N = 828) reported on their own mothers' parenting behaviors using the Parental Bonding Instrument (PBI) and were assessed for depression using the Structured Clinical Interview for DSM Disorders (SCID). The PBI includes scales for warmth (care scale) and over-control (protection scale), as well as subscales for behavioral control and psychological control. We used structural equation modeling to test the associations between depression and all PBI scales/subscales.
Results
Increased parental care was associated with lower probability of depression (B = −0.19, SE = 0.09). Parental protection was associated with higher probability of depression (B = 0.25, SE = 0.11). Among the protection subscales, behavioral control was associated with increased risk of depression (B = 0.24, 95 % SE = 0.11) and psychological control was associated with decreased risk of depression (B = −0.28, SE = 0.12).
Limitations
This cross-sectional study used retrospective self-reports of parenting experiences. Participants only reported on their mothers, not fathers or other caregivers.
Conclusions
In a rural Pakistani sample, maternal warmth was protective against adulthood depression. The association between maternal control and depression varied based on the type of control (behavioral or psychological), emphasizing the importance of nuanced measures of parental control in this context
Climate risk and financial stability : evidence from syndicated lending
Get PDFWe study the impact of unexpected climate shocks on banks' individual and systemic risks. Employing climate risk measures developed using the Billion-Dollar Weather and Climate Disasters data from the National Oceanic and Atmospheric Administration (NOAA) and Dealscan syndicated lending data, we find that climate risk exposure acquired through cross-state lending increases banks' individual and systemic risks. We also find that bank profitability helps offset some of the adverse effects of climate risk. Banks reduce lending and increase loan loss reserves after the experience of an unexpected climate shock. The loan-level analysis reveals that the effect of climate risk exposure on bank risks is more pronounced for loans granted for operating and capital expenditures. We contribute to a growing literature on the impact of climate risk on financial stability and the development of robust measures of climate risk for banks
Evolution of individual variation in a competitive trait : a theoretical analysis
No full textWhen competitive traits are costly, negative frequency dependence can maintain genetic variance. Most theoretical studies examining this problem assume binary polymorphisms, yet most trait variation in wild populations is continuous. We propose that continuous trait variation can result from continuous variation in resource quality and that, specifically, the shape of the resource distribution determines trait maintenance. We used an individual-based model to test which conditions favour the stable maintenance of variation and which cause temporal fluctuations in trait values. This approach, inspired by contrasting outcomes of previous studies regarding variance and fluctuations in trait values, clearly showed a decisive role played by the shape of resource distributions. Under extreme conditions, e.g., the absence of resource variation or with very scarce resources for weak competitors, traits evolved to a single non-competitive or highly competitive strategy, respectively. Most other distributions led to strong temporal fluctuations on trait values or the maintenance of stable, standing variation. Our results thus explain the contradicting outcomes of previous theoretical studies and, at the same time, provide hypotheses to explain the maintenance of genetic variation and individual differences. We suggest ways to empirically test the proposed effects of resource variation on trait maintenance
Advancing equitable ‘resilience imaginaries’ in the Global South through dialogical participatory mapping : experiences from informal communities in Brazil
Get PDFOver recent years, and as a result of the recent global health pandemic, resilience has become increasingly central to contemporary policy discourses in urban planning and development in both the Global North and Global South. Drawing from ongoing empirical studies of community resilience and everyday practices that have been co-designed and co-produced alongside Brazilian marginalised communities which are highly vulnerable to a range of natural hazards, this paper highlights the growing importance of dialogical stakeholder engagement methodologies in designing alternative urban visions – so-called resilience imaginaries or counter-cities - across the Global South based on social diversity, equity and spatial justice. More specifically, the dialogical participatory mapping approach outlined in this paper utilises citizen science approaches to develop local resilience imaginaries, building on the pedagogical work of Brazilian educator Paulo Freire and the conceptualisation of dialogue as a comprehensive and progressively unfolding methodological approach. Practically, we adopted a range of community engagement approaches that allowed local citizens to become more aware of their own risk context and embed this tacit knowledge into the operation of civil protection programmes. Our empirical results highlight the potential of such dialogical participatory approaches to capture lay knowledge from local citizens and contribute to the development of enhanced resilience approaches. The paper concludes by reflecting on the role of formerly marginalised voices in the advancement of local urban policy and on the novelty and promise of critical pedagogical approaches to co-production within existing regimes of urban governance and the imagining of radically independent counter-cities
The collapse of the green wall
No full textThe Conservative Party has usually done well in rural areas, but its ‘green wall’ is now under threat from Labour more than the Liberal Democrats. Farmers did not support Brexit any more than the general population, and in income terms they are currently doing well, but fear for the future. In addition, food security issues are more complex than they are portrayed, as are the relations with the devolved governments. In Scotland, the government there is much more popular among Scottish farmers whilst the government in Wales is doing much worse among farming communities
Exploring gender differences in Gen Z students’ attribution of obstacles influencing their academic and professional success
Get PDFUniversities are often criticised for perpetuating gender inequalities in the preparation of students for the workforce. Employing a mixed methods approach, we explore whether perceived obstacles to academic and professional success are gender-based. We analyse responses from generation Z management students (n=405) using attribution theory. We find that students predominantly perceive ‘effort’ as an enabler to their future success with gender disparities emerging when examining the multifaceted obstacles to their future success. Out of all demographic characteristics analysed, gender, and particularly a perceived lack of confidence by female students, is the most predominant and statistically significant factor. Through in-depth qualitative research we develop our understanding of these gendered student attributions, highlighting their potential impact on long-term professional success and their contribution to future earning inequalities. We examine the implications of our findings for educators and propose proactive strategies to tackle gendered disparities in the student experience