Crash frequency analysis of different types of urban roadway segments using generalized additive model

IntroductionThis paper utilizes generalized additive model to explore the potential non-linear relationship between crash frequency and exposure on different types of urban roadway segments.MethodsGeneralized additive models are used to analyze crash frequency data and compared with the commonly used crash rate method and generalized linear models using a five-year crash data set from Houston, Texas.ResultsThe study shows that the relationship between crash frequency and exposure varies by segment type and the linearity may only approximately exist in certain segment types. In addition, the generalized additive modeling results suggest that such relationship curves may not be monotonic. Finally, this study demonstrates that generalized additive models in general provide better flexibility and modeling performance than generalized linear models.Impact on IndustryThe generalized additive model provides a very promising alternative for crash frequency modeling and other safety studies.     

Biomechanical response targets for physical and computational models of the pediatric trunk

Objectives: This paper quantifies pediatric thoracoabdominal response to belt loading to guide the scaling of existing adult response data and to assess the validity of a juvenile porcine abdominal model for application to the development of physical and computational models of the human child. Methods: Table-top belt-loading experiments were performed on 6, 7, and 15 year-old pediatric post-mortem human subjects (PMHS). Response targets are reported for diagonal belt and distributed loading of the anterior thorax and for horizontal belt loading of the abdomen. Results: The pediatric PMHS exhibited abdominal response similar to the swine, including the degree of rate sensitivity. The thoraces of the PMHS were as stiff as, or slightly more stiff than, published adult corridors. Conclusions: An assessment of age-related changes in thoracic stiffness suggests that the effective stiffness of the chest increases through the fourth decade of life and then decreases, resulting in stiffness values similar for children and elderly adults.     

基于熵权模糊物元的高速公路路段安全综合评价

针对目前道路安全评价中信息屏蔽和主观性问题,利用模糊物元理论和熵权理论对高速公路安全水平进行了定量评价。在考虑影响道路安全水平多种因素基础上,构建了道路安全评价指标体系。以定量分析为主,将模糊物元、隶属函数及信息熵有机结合起来,建立了高速公路安全水平综合评价模型。以信息熵理论为基础确定了各评价指标的权重系数。将模型应用在新疆高速公路不同路段安全评价中,并与其它综合评价模型比较分析,验证该模型的有效性。研究结果表明该模型实用性强,计算过程简单,在道路安全评价中具有一定应用价值。     

变质派生矿床的成因分类

已有的分类及其评价 鲍格达诺维奇(1913)将变质派生矿床分为受变质矿床和变质矿床。乌索夫(1933)将变质派生矿床理解为“早期形成的矿床发生再结晶作用,并且这种再结晶作用(或称变     

保加利亚的二长岩及其铁铜矿化

保加利亚最重要的铁和铜的矿化与新深成岩体(白垩纪晚期到始新世晚期)有关,其中有许多铁矿、铜矿产在二长岩及二长岩类岩体里。罗多彼山中央地块的多金属矿化也是同二长岩类有联系,只是年代更新一些。二长岩及二长岩类岩体分布如下:     

萨哈林中生代地层陆源沉积岩的成因

为了查明地槽发育早期阶段的特性,与奥菲奥岩共生的陆源沉积岩层的研究引起了重大的兴趣。在大陆与海洋结合处的所谓过渡带上,陆源沉积岩成因特性的解释是极重要的。萨哈林岛的中生代(晚白垩世以前)盆地正是属于这样的地带。     

湖泊中溶解的氦:拉布拉多中部前寒武地块的铀矿勘探

一、引言 象氡一样,氦是未出露的铀或钍矿床的一种示踪元素,其最大优点是He~4很稳定,并能通过大多数岩石或矿物迅速扩散。此外,由于它溶解度极小,因此对进入地下水中比较小的He~4流量也能检测出来。近年来,精确分析氦同位素的质谱计,已经发展到这样一种程度,即对20克水样中溶解氦的He~3/He~4比值都很容易测量,其精度大约为0.2％(与大气氦相比)。     

影响大油气田形成的因素

我们企图找出一些大油气田的控制因素,这些因素能够解释油气在大多数产区的特殊产出情况,同时又能解释油气在世界上少数几个沉积盆地普遍存在的性质。