Integrating Climate and Ocean Change Vulnerability into Conservation Planning

Tropical coastal and marine ecosystems are particularly vulnerable to ocean warming, ocean acidification, and sea-level rise. Yet these projected climate and ocean change impacts are rarely considered in conservation planning due to the lack of guidance on how existing climate and ocean change models, tools, and data can be applied. Here, we address this gap by describing how conservation planning can use available tools and data for assessing the vulnerability of tropical marine ecosystems to key climate threats. Additionally, we identify limitations of existing tools and provide recommendations for future research to improve integration of climate and ocean change information and conservation planning. Such information is critical for developing a conservation response that adequately protects these ecosystems and dependent coastal communities in the face of climate and ocean change.     

框架码头主体与接岸结构在变水位条件下的相互作用研究

目前,国、内外针对水深和水位变幅较大的内河架空直立式框架码头的研究成果不多,针对码头使用过程中主体结构与接岸结构间相互作用的研究就更少。根据这类码头的受力特点,通过在码头前方承台的横梁与接岸结构之间增设弹簧隔振装置模拟接岸结构和码头主体的作用力,利用PLAXIS软件研究不同的水位下降速度对码头主体与接岸结构间相互作用的影响,求得到结构的内力和变形,并在此基础上提出弹簧的刚度系数。     

Variability of snow and ice thermal, physical and optical properties pertinent to sea ice algae biomass during spring

Changes in the thermal, physical and optical properties of the snow–sea ice system and feedbacks between various temporal and spatial scales affect accumulation of microalgae at the sea ice bottom and are the focus of this research. During the spring transition period, May 4 to June 9, 2002, we closely monitored atmospheric conditions and properties of the snow–sea ice system, including thermal, physical and optical properties of the snow cover (e.g., temperature, grain size, light attenuation), ice thickness and salinity, and biomass of bottom ice algae. Results show that snowdrift size averaged 31.2 by 10.6 m with a depth range of 2 to 45 cm. Snowpacks also varied in age, distinguished by coincident peaks of snow salinity and grain size and a lower PAR extinction coefficient. Spatial variability of the snowpack was superimposed by temporal variability associated with seasonal snow–ice melt and wind redistribution of snow. Maximum biomass of ice algae was observed under intermediate snow covers. Under thin snow covers, algae biomass declined steadily coincident with seasonal warming and desalination of the ice cover. Under thick snow covers, algae biomass was negatively correlated with snow depth. These results suggest that thin snow covers were associated with a thermal effect causing sloughing of algae, whereas under deep snow, algae were still light limited and thermally insulated from the warming atmosphere. Our results highlight the importance of snow cover history on the sea ice system operating below. Furthermore, in the context of current climate change scenarios, shifts in snow depth would result in decreases of ice algae biomass.     

基于元胞自动机的双车道变道交通流特性研究

在庞杂的城市交通环境下,驾驶员为了寻求更快的速度,常常采用主动的换道行为。由于汽车使用量逐年增长,换道引起的交通事故经常发生。研究车辆变道行为,寻求有效措施减少交通事故的发生,对提高道路安全性具有积极的意义。本文以多车道系统中车辆变道行为为研究对象,以元胞自动机理论为基础,对比分析单向单车道、单向双车道换道行为,并运用MATLAB仿真软件进行分析,获得变道交通流的相关特性曲线。     

基于轮荷分析的车辆稳态转向特性虚拟仿真

借助虚拟样机仿真技术,发现某预研项目车辆具有过多转向趋势,在全面分析车轴左右轮荷变化的基础上,深入探讨了车辆转向特性的影响因素．针对本项目提出可通过加粗前悬架横向稳定杆直径的办法来获得车辆的不足转向特性。通过对多种匹配方案的仿真分析和对比权衡,并结合国标对稳态回转实验的评价打分方法,最终确定把前后悬架侧倾角刚度之比由1．17增加到1．96,此时车辆的过度转向趋势得以消除,并具有了适度的不足转向特性。     

隧道施工隧址区土壤因子变化规律研究

文章针对我国隧道施工造成周边土壤环境变化的现状,通过对隧址区周边土壤样品的对比分析,找出了土壤因子的变化规律及原因,为隧道施工后土壤环境的恢复与改良提供参考。     

Bounded rationality and irreversible network change

A network change is said to be irreversible if the initial network equilibrium cannot be restored by revoking the change. The phenomenon of irreversible network change has been observed in reality. To model this phenomenon, we develop a day-to-day dynamic model whose fixed point is a boundedly rational user equilibrium (BRUE) flow. Our BRUE based approach to modeling irreversible network change has two advantages over other methods based on Wardrop user equilibrium (UE) or stochastic user equilibrium (SUE). First, the existence of multiple network equilibria is necessary for modeling irreversible network change. Unlike UE or SUE, the BRUE multiple equilibria do not rely on non-separable link cost functions, which makes our model applicable to real-world large-scale networks, where well-calibrated non-separable link cost functions are generally not available. Second, travelers’ boundedly rational behavior in route choice is explicitly considered in our model. The proposed model is applied to the Twin Cities network to model the flow evolution during the collapse and reopening of the I-35 W Bridge. The results show that our model can to a reasonable level reproduce the observed phenomenon of irreversible network change.     

Scientific research about climate change mitigation in transport: A critical review

This paper seeks to develop a deeper understanding of the research on climate change mitigation in transport. We suggest that work to date has focused on the effects of improvements in transport technologies, changes in the price of transport, physical infrastructure provision, behavioural change and alternative institutional arrangements for governing transport systems. In terms of research methodologies, positivist and quantitative analysis prevails, although there are signs of experimentation with non-positivist epistemologies and participatory methods. These particular engagements with climate change mitigation reflect mutually reinforcing tendencies within and beyond the academic transport community. We first draw on a revised version of Thomas Kuhn’s philosophy of science to explore the path dependencies within transport studies, which are at least partly responsible for the predisposition towards quantitative modelling and technology, pricing and infrastructure oriented interventions in transport systems. We then employ the governmentality perspective to examine how transport academics’ engagements with climate change mitigation depend on and align with more general understandings of climate change in UK society and beyond. The analysis makes clear that ecological modernisation and neo-liberal governmentality more generally provide the context for the current focus on and belief in technological, behaviour change, and especially market-based mitigation strategies. While current research trajectories are important and insightful, we believe that a deeper engagement with theoretical insights from the social sciences will produce richer understandings of transport mitigation in transport and briefly outline some of the contributions thinking on socio-technical transitions and practice theories can make.     

沥青路面降温方法

车辙的出现和温度环境有很大关系。沥青路面通常为黑色,空隙率小而封闭,吸热迅速,放热缓慢,高温条件下沥青混合料劲度模量大幅下降,抗变形能力急剧降低,容易出现车辙病害。因此,沥青路面降温对预防车辙尤为重要。近年来,随着沥青路面降温逐渐得到重视,降温方法得到极大的丰富和发展。文章主要总结了热反射降温法和蒸发降温法的研究现状,分析了现有技术存在的缺陷和需要做出的改进。此外,还对添加相变材料、红外粉、光催化剂和设置隔热层、热管等方法进行了探讨。     

基于BP神经网络的高速公路入口合流区域换道行为研究

为了应对高速公路入口合流区域并线事故频繁发生,在分析车辆并线行为影响因素的基础上,利用BP神经网络方法建立了车辆在该区域的决策模型,用来预测驾驶人的并线行为决策,保障车辆和驾驶人的安全.借助详细的车辆轨迹数据对模型进行了学习与测试,模型的测试结果表明:建立的BP神经网络模型用于预测驾驶人并线行为具有较高的准确度,并线车辆相对于目标车道前方车辆的相对速度是驾驶人并线时需要考虑的最重要因素.同时模型还可以进一步应用于交通仿真的研究以及驾驶人辅助系统的开发.