112 research outputs found
A Type Theory for Probabilistic { extdollar}{ extdollar}{ extbackslash}lambda { extdollar}{ extdollar}{ extendash}calculus
No full textWe present a theory of types where formulas may contain a choice constructor. This constructor allows for the selection of a particular type among a finite set of options, each corresponding to a given probabilistic term. We show that this theory induces a type assignment system for the probabilistic λ –calculus introduced in an earlier work by Chris Hankin, Herbert Wiklicky and the author, where probabilistic terms represent probability distributions on classical terms of the simply typed λ –calculus. We prove the soundness of the type assignment with respect to a probabilistic term reduction and a normalization property of the latter
Probabilistic Analysis of Programs: A Weak Limit Approach
No full text25/06/14 meb. ok to add author retained copyright at time of conference
B physics from lattice simulations
No full textIn this thesis we present four main results: (i) The computation of the matching coefficients for a complete set of 4-quark operators between the continuum HQET and Lattice HQET. This result extends and completes a preceding computation of the matching coefficients relevant for the B"0 - B-bar"0 mixing (and corrects a mistake in the latter). (ii) The lattice evaluation of the coupling g_B_*_B_#pi#, which is related to the form factor at zero momentum transfer of the axial current between B*- and B-states. Moreover we show how this coupling constant is also related to the coupling g between heavy mesons and low-momentum pions that appears the effective heavy meson chiral Lagrangian. We find the value g = 0.42(4)(8). Besides its theoretical interest, the phenomenological implications of such a determination are discussed. (iii) The lattice evaluation of the matrix elements of the four-quark operators which contribute to the lifetimes of B-mesons and the #LAMBDA#_b-baryon. We find that the spectator effects are larger than naively expected and are in part responsible for the discrepancy between the O(1/m_b"2) theoretical prediction and experimental measurement of the ratio of lifetimes #tau#(#LAMBDA#_b)/#tau#(B"0). In fact for this ratio we obtain the value 0.93(1)(2). (iv) A re-evaluation of the B_B parameter relevant for the B"0 - B-bar"0 mixing, using our correct result for the matching coefficients. We obtain B_B = 0.96(3). (author)SIGLEAvailable from British Library Document Supply Centre-DSC:DXN027871 / BLDSC - British Library Document Supply CentreGBUnited Kingdo
An exploratory study of the abilities of professional driving teachers to detect high-risk young drivers prior to their licensure
No full textMémoire numérisé par la Direction des bibliothèques de l'Université de Montréal
Adolescent driver risk taking and driver education: Evidence of a mobility bias in public policymaking
No full textThe relationship between markers of risk-taking tendecies and the first year driving records of young drivers
No full textThèse numérisée par la Direction des bibliothèques de l'Université de Montréal
Assessing Moral Reasoning, Cognitive Distortions and Driving Style in the Context of Post-License Young Driver Coaching
No full textAs part of the Dutch post-license young driver coaching program, Drive Xperience (DX), the level of moral reasoning was explored in relation to self-reported violating driving behaviors. Drawing from literature in the field of juvenile crime, three online assessments were developed to measure: a) social driving behavior; b) moral justification for rule compliance, and: c) cognitive distortions in relation to socially undesirable driving behavior. The assessments were administered between fall 2014 and fall 2016 to1660 participants in the DXprogram. The results show that immature levels of moral reasoning and prevalence of cognitive distortions are strongly associated with self-reported speed choice, space competition and traffic law violations
A Profile of Adolescents who Attend Driver Education for the Insurance Discount: Are Insurers Rewarding Bad Risks?
No full textProblem: The overrepresentation of adolescent drivers in crashes is a robust phenomenon.
Driver education (DE) is a popular countermeasure, and in most North American
juridictions, insurers grant automobile insurance premium discounts to DE graduates.
However, over the past 20 years, evaluations have consistently demonstrated that DE
does not reduce, and may even increase, crash risk among adolescent novice drivers.
Providing premium reduction incentives to DE graduates may possibly increase crash
risk in two ways. One, by reducing the overall cost of licensing and car ownership, insurance
may increase driving exposure. Two, insurance may increase morale hazard, a
careless attitude toward prevention. The human and financial losses resulting from adolescent
crashes are a serious problem for public health and for insurers. Insurance is also
known to increase moral hazard, a tendency to make dishonest claims - losses due to
fraud are a significant problem for insurers. Therefore, the DE insurance discount may
not be optimally efficient for reducing insurers' losses or for improving the public health.
One approach to invesligating the effects of the DE insurance discount is to study the
characteristics and the driving records of adolescents who are insurance-motivated, i.e.
those who attend DE partly or entirely for the insurance discount.Method: A cohort of 1,804 novice drivers 16- to 19-years of age of both sexes completed
an extensive questionnaire on learning methods, including motivation to attend or not to
attend DE, risk taking, and lifestyles. Questionnaire data were linked on an individual
basis with government records on exam performance, violations, and crashes. Among the
participants who attended DE (N = 1,536), the importance of the insurance discount in
their motivation to attend DE was studied in relation to violation and crash records during
the first 450 days of unsupervised driving and explanatory variables from the questionnaire.Results: Insurance-motivated participants, compared to those who were not motivated
by the insurance discount, were more likely to have: greater violation risk, more tolerant
attitudes towards speeding and risk taking, and less financial support from family for all
licensing and driving related expenses. Insurance motivation was also associated with the
likelihood of presenting fraudulent DE certificates and expressing a willingness to defraud
insurance companies.Discussion: Increased violation and crash risk associated with insurance-motivation
may possibly be due to greater morale hazard. The data also indicate thar insurance motivation
may be associated with greater moral hazard and potential future losses for
insurers. Alternative methods for insuring adolescent drivers are suggested with the aim
of decreasing insurance losses and injury risk by attempting to decrease both morale and
moral hazard.Problème : La surreprésentation des conducteurs automobiles adolescents impliqués
dans des collisions est un phénomène robuste. L’éducation routière (ER) est une intervention
populaire et, dans la plupart des juridictions Nord Américaines, plusieurs assureurs
donnent des rabais sur les primes d’assurances automobiles aux nouveaux
conducteurs ou conductrices qui présentent une attestation de complétion d’un cours de
conduite. Cependant, depuis 20 ans, les études ont démontré que le fait de suivre un cours
de conduite ne réduit pas, et même pourrait augmenter le risque d’être impliqué dans une
collision chez les jeunes conducteurs. Les rabais sur les primes d’assurances automobiles
pour les nouveaux conducteurs ou conductrices avec des attestations ER peuvent augmenter
leur risque d’être impliqués dans une collision principalement pour deux raisons.
Un, en réduisant le coût total d’obtenir un permis de conduire et de devenir propriétaire
d’une voiture, le rabais d’assurance pourrait augmenter l’exposition au risque. Deux,
l’assurance peut augmenter le risque d’une attitude négligente envers la prévention. Les
pertes humaines et financières provoquées par les collisions routières impliquant des jeunes
conducteurs et conductrices posent un grave problème pour la santé publique et les
assureurs. Il est aussi connu que l’assurance peut augmenter le risque moral, une tendance
à faire de fausses réclamations - les pertes provoquées par les fausses réclamations
sont un problème important pour les assureurs. Par conséquent, le rabais ER n’a pas
nécessairement une efficacité optimale pour réduire les pertes des assureurs ou pour améliorer
la santé publique. Une approche pour évaluer les effets du rabais ER est d’étudier
les caractéristiques et le bilan routier des nouveaux conducteurs et conductrices qui
étaient motivés à suivre un cours de conduite partiellement ou complètement dans le but
d’obtenir un rabais d’assurance.Méthode : Une cohorte de 1 804 nouveaux conducteurs et conductrices ayant moins de
vingt ans a répondu à 149 questions réparties sur trois volets : les méthodes d’apprentissage
de la conduite automobile, incluant les motivations pour suivre ou non un cours de
conduite, la propension à prendre des risques. et le style de vie. La SAAQ a fourni les
dossiers de conduite, et toutes les données ont été anonymisées et jumelées aux fins d’analyse. Pour les participants qui ont suivi un cours de conduite (N = 1536), le niveau
d’importance accordé au rabais d’assurance a été étudié et sa relation avec leurs bilans
routiers pendant les 450 premiers jours de conduite sans supervision ainsi qu’avec
d’autres variables explicatives du questionnaire.Résultats : Les participants motivés par un rabais d’assurance, relativement aux participants
non motivés par un rabais d’assurance, avaient plus de chance d’avoir plus d’infractions
de la route, des attitudes plus tolérantes envers la conduite à haute vitesse et la prise
de risque, moins de support financier de la part de leur famille pour les coûts associés à
l’obtention du permis de conduire et les autres dépenses reliées à la conduite. La motivation
au rabais d’assurance était aussi associée avec une probabilité plus élevée de présenter
des attestations erronées de complétion d’un cours de conduite et d’exprimer une
volonté de pratiquer un acte de fraude à l’égard des compagnies d’assurances.Discussion : Le risque plus élevé d’avoir des infractions et des collisions qui est associé
avec la motivation d’obtenir un rabais d’assurance pourrait être expliqué par une attitude
négligente pour la prévention. Les résultats indiquent aussi que la motivation pour un
rabais d’assurance peut être associée avec un risque moral plus grand et le potentiel de
pertes pour les assureurs dans l’avenir. Quelques politiques d’assurances alternatives
pour diminuer les attitudes négligentes et le risque moral sont suggérées dans le but de
réduire les pertes pour les assureurs et le risque de collision
Transfer of Skills Learned on a Driving Simulator to On-Road Driving Behavior
No full text A long-term, naturalistic, prospective-cohort transfer of training study was conducted in commercial driving schools in Quebec, Canada, to test the effects on driver performance and behavior of integrating driving simulator–based training (DSBT) into the driver education program. For the study, 1 h of DSBT could be substituted for 1 h of on-road training for up to six of the mandatory 15 h. Four driving schools provided a convenience sample of 1,120 learner drivers (average age 17.7 and 52.7% female) between January 2010 and December 2014. Of the study sample, 95% received 1 to 4 h of DSBT. Those in the comparison group were all new, young Quebec drivers who had completed the mandatory driver education program in the same period. This paper reports on the association between DSBT and government driving records for 2 years after licensing. The DSBT group recorded lower infraction rates and, controlling for vehicle ownership and age, comparable crash rates. The lower infraction rates for males, despite the higher vehicle ownership normally associated with greater and riskier driving exposure, are a positive and unexpected finding. Crashes are multifactorial events less obviously related to drivers’ skills or intentions, and the comparable crash rates potentially indicate absence of overconfidence attributable to a form of advanced driver training. Overall, these results show that the substitution of relatively few hours of DSBT for on-road training is associated with reduced infractions and has no apparent influence on crashes in the first 2 years of unsupervised driving after licensing. </jats:p
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