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991.
Application of the Hyper‐Poisson Generalized Linear Model for Analyzing Motor Vehicle Crashes
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S. Hadi Khazraee Antonio Jose Sáez‐Castillo Srinivas Reddy Geedipally Dominique Lord 《Risk analysis》2015,35(5):919-930
The hyper‐Poisson distribution can handle both over‐ and underdispersion, and its generalized linear model formulation allows the dispersion of the distribution to be observation‐specific and dependent on model covariates. This study's objective is to examine the potential applicability of a newly proposed generalized linear model framework for the hyper‐Poisson distribution in analyzing motor vehicle crash count data. The hyper‐Poisson generalized linear model was first fitted to intersection crash data from Toronto, characterized by overdispersion, and then to crash data from railway‐highway crossings in Korea, characterized by underdispersion. The results of this study are promising. When fitted to the Toronto data set, the goodness‐of‐fit measures indicated that the hyper‐Poisson model with a variable dispersion parameter provided a statistical fit as good as the traditional negative binomial model. The hyper‐Poisson model was also successful in handling the underdispersed data from Korea; the model performed as well as the gamma probability model and the Conway‐Maxwell‐Poisson model previously developed for the same data set. The advantages of the hyper‐Poisson model studied in this article are noteworthy. Unlike the negative binomial model, which has difficulties in handling underdispersed data, the hyper‐Poisson model can handle both over‐ and underdispersed crash data. Although not a major issue for the Conway‐Maxwell‐Poisson model, the effect of each variable on the expected mean of crashes is easily interpretable in the case of this new model. 相似文献
992.
Layered defenses are necessary for protecting the public from terrorist attacks. Designing a system of such defensive measures requires consideration of the interaction of these countermeasures. In this article, we present an analysis of a layered security system within the lower Manhattan area. It shows how portfolios of security measures can be evaluated through portfolio decision analysis. Consideration is given to the total benefits and costs of the system. Portfolio diagrams are created that help communicate alternatives among stakeholders who have differing views on the tradeoffs between security and economic activity. 相似文献
993.
Kirsi Juhila Christopher Hall Kirsi Günther Suvi Raitakari Sirpa Saario 《Social Policy & Administration》2015,49(5):612-630
Across Western welfare regimes, policies emphasize that service users should have more choices regarding their services. This article examines how service choices are presented, responded to and decided in interactions between service users and professionals in mental health transition meetings. Choice is often associated with consumerist user involvement ideas, but in mental health choice also relates to the democratic user involvement approach and to shared decision making between professionals and service users. The results of the study show that professionals construct service users as consumers by offering service options in choice making sequences, expecting users to make appropriate choices. Service users mostly act like consumers by responding to these choice options. However, the study also demonstrates that the professionals do not always accept the user's first choice but respond to them as non‐preferred. Sometimes, they also suggest choices on behalf of the users. In these ‘non‐accepting’ sequences, choices are negotiated in interaction between the parties, rather than users acting as autonomous choice makers. The sequences are based on two kinds of professional reasoning: first, the professional‐led needs assessment and, second, the structure of the service package that the user is being offered. This negotiation has elements of shared decision making and the ‘logic of care’. But it also has elements of paternalist control which challenge both consumerist and democratic service user involvement and suggests consideration of more collectively oriented service user actions. 相似文献
994.
Quantitative risk assessments for physical, chemical, biological, occupational, or environmental agents rely on scientific studies to support their conclusions. These studies often include relatively few observations, and, as a result, models used to characterize the risk may include large amounts of uncertainty. The motivation, development, and assessment of new methods for risk assessment is facilitated by the availability of a set of experimental studies that span a range of dose‐response patterns that are observed in practice. We describe construction of such a historical database focusing on quantal data in chemical risk assessment, and we employ this database to develop priors in Bayesian analyses. The database is assembled from a variety of existing toxicological data sources and contains 733 separate quantal dose‐response data sets. As an illustration of the database's use, prior distributions for individual model parameters in Bayesian dose‐response analysis are constructed. Results indicate that including prior information based on curated historical data in quantitative risk assessments may help stabilize eventual point estimates, producing dose‐response functions that are more stable and precisely estimated. These in turn produce potency estimates that share the same benefit. We are confident that quantitative risk analysts will find many other applications and issues to explore using this database. 相似文献
995.
Galateia Terti Isabelle Ruin Jonathan J. Gourley Pierre Kirstetter Zachary Flamig Juliette Blanchet Ami Arthur Sandrine Anquetin 《Risk analysis》2019,39(1):140-161
This article focuses on conceptual and methodological developments allowing the integration of physical and social dynamics leading to model forecasts of circumstance‐specific human losses during a flash flood. To reach this objective, a random forest classifier is applied to assess the likelihood of fatality occurrence for a given circumstance as a function of representative indicators. Here, vehicle‐related circumstance is chosen as the literature indicates that most fatalities from flash flooding fall in this category. A database of flash flood events, with and without human losses from 2001 to 2011 in the United States, is supplemented with other variables describing the storm event, the spatial distribution of the sensitive characteristics of the exposed population, and built environment at the county level. The catastrophic flash floods of May 2015 in the states of Texas and Oklahoma are used as a case study to map the dynamics of the estimated probabilistic human risk on a daily scale. The results indicate the importance of time‐ and space‐dependent human vulnerability and risk assessment for short‐fuse flood events. The need for more systematic human impact data collection is also highlighted to advance impact‐based predictive models for flash flood casualties using machine‐learning approaches in the future. 相似文献
996.
After observing ostracism or social exclusion, older children, adolescents and adults report decreased satisfaction of the need for control. Attempting to regain control can motivate aggression in ostracized adults. Research has shown that the onset of ostracism’s harmful effects on children’s behavior is at preschool age. We investigated whether preschoolers would exert more control after witnessing ostracism. A sample of 53 children (Mage = 5 years, 5 months) first watched priming videos either showing ostracism or not. Subsequently, they participated in two ball games. In both of the games (order counterbalanced), children could control the flow of a ball’s motion, either live between two people (i.e., social control) or between two bars on a laptop screen (i.e., non‐social control). Overall, children understood social exclusion when it was displayed in the videos. We found an effect of observed ostracism only on social control. Four‐ to five‐year‐old boys who witnessed ostracism stopped a ball game between two persons longer than boys who did not witness ostracism. Our results suggest that observing social exclusion elevates young boys’ need for control over a social situation. Girls showed a different pattern but their responses did not differ significantly between ostracism and non‐ostracism conditions. 相似文献
997.
In this article, a classification model based on the majority rule sorting (MR‐Sort) method is employed to evaluate the vulnerability of safety‐critical systems with respect to malevolent intentional acts. The model is built on the basis of a (limited‐size) set of data representing (a priori known) vulnerability classification examples. The empirical construction of the classification model introduces a source of uncertainty into the vulnerability analysis process: a quantitative assessment of the performance of the classification model (in terms of accuracy and confidence in the assignments) is thus in order. Three different app oaches are here considered to this aim: (i) a model–retrieval‐based approach, (ii) the bootstrap method, and (iii) the leave‐one‐out cross‐validation technique. The analyses are presented with reference to an exemplificative case study involving the vulnerability assessment of nuclear power plants. 相似文献
998.
Sally Sales 《Child & Family Social Work》2015,20(2):149-158
Since its legal inception in 1926, adoption work has been centrally concerned with the matter of the adopted child's ‘first’ or prior life, whilst also focussed on achieving a new and secure substitute family for that child. Adoptive kinship has been formed through this dual and contradictory concern, a concern that has produced diverse policies and practices over the last 90 years. Drawing on Foucault's concept of technologies of the subject, this paper is an exploration of adoptive kinship within the new context of open adoption, a set of practices that more actively promotes the involvements of the adopted child's former family. These practices both promote a radical reworking of adoptive kinship, as well as confirming its more orthodox moorings. Drawing on an adoption archive study, the paper concludes with an analysis of letterbox contact to explore how far this form of open practice transforms adoptive kinship in the contemporary era. 相似文献
999.
Emelie Shanks Ulf Jonsson Stefan Wiklund Alexander Rozental 《Child & Family Social Work》2020,25(1):92-99
Research concerning outcomes for children who have been placed in out‐of‐home care has indicated that the care may have unwanted consequences. However, there has been no coherent terminology for differentiating between different types of such unwanted consequences. In this article therefore, we attempt to disentangle different aspects of potentially harmful care for looked after children, as well as to discuss potential pathways to more systematically approach and report adverse events for this group. In this endeavour, we turn to two adjacent disciplines, medicine and psychology, where these issues have received more interest. The applicability of the concepts used in these fields is discussed, and it is concluded that although they provide some help in categorizing different aspects of harmful care, the complexity of out‐of‐home care makes existing models difficult to adopt without adjustments. This has consequences for the possibility of evaluating care in research, as well as for monitoring adverse events in practice. Importantly, the causality will often be unknown. We therefore suggest that it is essential to shed more light on how decisions should be made about when to intervene or not in out‐of‐home care, despite limited information. 相似文献
1000.
Simon French Nikolaos Argyris Stephanie M. Haywood Matthew C. Hort Jim Q. Smith 《Risk analysis》2019,39(1):9-16
In any crisis, there is a great deal of uncertainty, often geographical uncertainty or, more precisely, spatiotemporal uncertainty. Examples include the spread of contamination from an industrial accident, drifting volcanic ash, and the path of a hurricane. Estimating spatiotemporal probabilities is usually a difficult task, but that is not our primary concern. Rather, we ask how analysts can communicate spatiotemporal uncertainty to those handling the crisis. We comment on the somewhat limited literature on the representation of spatial uncertainty on maps. We note that many cognitive issues arise and that the potential for confusion is high. We note that in the early stages of handling a crisis, the uncertainties involved may be deep, i.e., difficult or impossible to quantify in the time available. In such circumstance, we suggest the idea of presenting multiple scenarios. 相似文献