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51.
Introduction: Random Breath Testing (RBT) remains a primary method to both deter and apprehend drink drivers, yet a large proportion of road fatalities continue to be caused by the offense. Outstanding questions remain regarding how much exposure to RBT operations is needed to influence deterrence-based perceptions and subsequent offending. Method: Given this, licensed motorists (N = 961) in Queensland were recruited to complete a questionnaire either in the community (N = 741) or on the side of the road after just being breath tested (N = 243). Survey items measured different types of exposure to RBT operations (e.g., “seen” vs. “being tested”) and subsequent perceptions of apprehension as well as self-reported drink driving behaviors. Results: The key findings that emerged were: motorists were regularly exposed to RBT operations (both viewing and being tested), such exposure was not significantly correlated with perceptions of apprehension certainty, and a sizable proportion reported engaging in drink driving behaviors (e.g., approx. 25%), although roadside participants naturally reported a lower percentage of offending behaviors. Importantly, it was revealed that current “observations” of RBT was sufficient, but not actual levels of active testing (which needed to be doubled). Nevertheless, higher levels of exposure to RBT operations was found to be predictive of a lack of intention to drink and drive again in the future. Conclusions: This paper suggests that mere exposure to enforcement may not create the intended rule compliance, and that the frequency of exposure is also essential for the roadside.  相似文献   
52.
This paper examines the consequences of using a static model of recreation trip-taking behavior when the underlying decision problem is dynamic. Specifically we examine the implications for trip forecasting and welfare estimation using a panel dataset of Lake Michigan salmon anglers for the 1996 and 1997 fishing seasons. We derive and estimate both a structural dynamic model using Bellman's equation, and a reduced-form static model with trip probability expressions mimicking those of the dynamic model. We illustrate an inherent identification problem in the reduced-form model that creates biased welfare estimates, and we discuss the general implications of this for the interpretation of preference parameters in static models. We then use both models to simulate trip taking behavior and show that although their in-sample trip forecasts are similar, their welfare estimates and out-of-sample forecasts are quite different.  相似文献   
53.
Deterioration of surface ozone (O3) pollution in Northern China over the past few years received much attention. For many cities, it is still under debate whether the trend of surface O3 variation is driven by meteorology or the change in precursors emissions. In this work, a time series decomposition method (Seasonal-Trend decomposition procedure based on Loess (STL)) and random forest (RF) algorithm were utilized to quantify the meteorological impacts on the recorded O3 trend and identify the key meteorological factors affecting O3 pollution in Tianjin, the biggest coastal port city in Northern China. After “removing” the meteorological fluctuations from the observed O3 time series, we found that variation of O3 in Tianjin was largely driven by the changes in precursors emissions. The meteorology was unfavorable for O3 pollution in period of 2015-2016, and turned out to be favorable during 2017-2021. Specifically, meteorology contributed 9.3 µg/m3 O3 (13%) in 2019, together with the increase in precursors emissions, making 2019 to be the worst year of O3 pollution since 2015. Since then, the favorable effects of meteorology on O3 pollution tended to be weaker. Temperature was the most important factor affecting O3 level, followed by air humidity in O3 pollution season. In the midday of summer days, O3 pollution frequently exceeded the standard level (>160 µg/m3) at a combined condition with relative humidity in 40%-50% and temperature > 31°C. Both the temperature and the dryness of the atmosphere need to be subtly considered for summer O3 forecasting.  相似文献   
54.
There are several ways of controlling the propagation of a contagious disease. For instance, to reduce the spreading of an airborne infection, individuals can be encouraged to remain in their homes and/or to wear face masks outside their domiciles. However, when a limited amount of masks is available, who should use them: the susceptible subjects, the infective persons or both populations? Here we employ susceptible-infective-recovered (SIR) models described in terms of ordinary differential equations and probabilistic cellular automata in order to investigate how the deletion of links in the random complex network representing the social contacts among individuals affects the dynamics of a contagious disease. The inspiration for this study comes from recent discussions about the impact of measures usually recommended by health public organizations for preventing the propagation of the swine influenza A (H1N1) virus. Our answer to this question can be valid for other eco-epidemiological systems.  相似文献   
55.
为实现有效的不安全行为纠错,提升自我行为控制效果,基于24Model构建不安全动作的内在致因分析模型及分析程序,包含5项能力要素、15个维度因子和具有完整逻辑程序的4阶段步骤,并采用随机森林(RF)方法以煤矿安全专业人员为研究对象开展了不安全动作内在致因实证研究.结果 表明:对目标不安全动作影响最大的内在致因能力要素为...  相似文献   
56.
Quantifying dispersal is crucial both for understanding ecological population dynamics, and for gaining insight into factors that affect the genetic structure of populations. The role of dispersal becomes pronounced in highly fragmented landscapes inhabited by spatially structured populations. We consider a landscape consisting of a set of habitat patches surrounded by unsuitable matrix, and model dispersal by assuming that the individuals follow a random walk with parameters that may be specific to the habitat type. We allow for spatial variation in patch quality, and account for edge-mediated behavior, the latter meaning that the individuals bias their movement towards the patches when close to an edge between a patch and the matrix. We employ a diffusion approximation of the random walk model to derive analytical expressions for various characteristics of the dispersal process. For example, we derive formulae for the time that an individual is expected to spend in its current patch i, and for the time that it will spend in the matrix, both conditional on the individual hitting next a given patch j before hitting any of the other patches or dying. The analytical formulae are based on the assumptions that the landscape is infinitely large, that the patches are circularly shaped, and that the patches are small compared to interpatch distances. We evaluate the effect of these assumptions by comparing the analytical results to numerical results in a real patch network that violates all of the three assumptions. We then consider a landscape that fulfills the assumptions, and show that in this case the analytical results are in a very good agreement with the numerical results. The results obtained here allow the construction of computationally efficient dispersal models that can be used as components of metapopulation models.  相似文献   
57.
The concept of the renewal property is extended to processes indexed by a multidimensional time parameter. The definition given includes not only partial sum processes, but also Poisson processes and many other point processes whose jump points are not totally ordered. Various properties of renewal processes are discussed. Renewal processes are proposed as a basis for modelling the spread of a forest fire under a prevailing wind.
B. Gail IvanoffEmail:
  相似文献   
58.
In this research combustion of iron dust particles in a medium with spatially discrete sources distributed in a random way has been studied using a numerical approach. A new thermal model is generated to estimate flame propagation speed and quenching distance in a quiescent reaction medium. The flame propagation speed is studied as a function of iron dust concentration and particle diameter. The predicted propagation speeds as a function of these parameters are shown to agree well with experimental measurements. In addition, the minimum ignition energy has also been investigated as a function of equivalence ratio and particle diameter. The quenching distance has been studied as a function of particle diameter and validated by the experiment. Considering random distribution of particles, the obtained results provide more realistic and reasonable predictions of the combustion physics compared to the results of the uniform distribution of particles.  相似文献   
59.
对苯乙烯/环氧丙烷装置进行腐蚀回路划分,并将腐蚀回路中的压力管道按照管径、材质及用途等因素划分为不同的组别后进行RBI分析。根据风险评估结果,结合压力管道的使用情况、失效机理及剩余使用寿命等确定下一个检验周期和检验策略。以腐蚀回路中的组别作为检验单元,根据其失效可能性及风险等级确定各检验单元的检验比例和检验方法进行在线检验。结果表明:基于RBI分析结果的压力管道在线抽检方法可以验证风险评估的结果,同时还可以满足使用单位对管道的风险控制要求。  相似文献   
60.
王保乾 《环境技术》2000,18(2):2-8,26
本文简述运输环境和试验条件的制订对模拟运输试验的各种方法作了简单评述,尤其是对利用电子--液压振动台对大型整体产品在悬臂梁状态的试验作了介绍。最后说明一种能模拟带有高峰值随机振动的试验技术,以改进现有数控设备的不足。  相似文献   
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