Impact of perceptual countermeasures on driving behavior at curves using driving simulator

Objective: The probability of crash occurrence on horizontal curves is 1.5 to 4 times higher than that on tangent sections. A majority of these crashes are associated with human errors. Therefore, human behavior in curves needs to be corrected.

Methodology: In this study, 2 different road marking treatments, optical circles and herringbone patterns, were used to influence driver behavior while entering a curve on a 2-lane rural road section. A driving simulator was used to perform the experiment. The simulated road sections are replicas of 2 real road sections in Flanders.

Results: Both treatments were found to reduce speed before entering the curve. However, speed reduction was more gradual when optical circles were used. A herringbone pattern had more influence on lateral position than optical circles by forcing drivers to maintain a safe distance from opposing traffic in the adjacent lane.

Conclusion: The study concluded that among other low-cost speed reduction methods, optical circles are effective tools to reduce speed and increase drivers’ attention. Moreover, a herringbone pattern can be used to reduce crashes on curves, mainly for head-on crashes where the main problem is inappropriate lateral position.     

水资源管理模式发展趋势探析

随着工业进步和社会发展,水污染亦日趋严重,已对人类的生存安全构成重大威胁,成为人类健康、经济和社会可持续发展的重大障碍。水安全与水资源管理是全球战略问题,如何进行水资源管理和研究也是当今社会面临的难题。本文就水资源管理模式发展趋势进行阐述。     

武汉市湿地破碎化对生态系统服务价值的影响研究

以湖泊资源丰富的武汉市为例,通过景观格局指数测定该市湿地破碎化程度,借助GIS技术评估该市湿地生态系统服务价值,并探讨了城市湿地破碎化对生态系统服务价值的影响。结果表明:①2000—2015年武汉市湿地总体破碎化趋势有所缓和,但人工湿地相较于自然湿地破碎化程度要高,特别是2010—2015年湿地总面积下降了2.80%,而斑块密度上升了4.12%,湖泊破碎化程度较高。②2000—2015年,武汉市湿地ESV增长了323.27亿元,各类型湿地的生态系统服务价值表现为湖泊>水库坑塘>河流>沼泽。③湿地景观破碎化与部分调节性、支持性和文化性服务功能存在着显著相关关系。     

Spatial modelling of socioeconomic data to understand patterns of human-caused wildfire ignition risk in the SW of Madrid (central Spain)

The majority of wildfires in the Mediterranean Basin are caused directly or indirectly by human activity. Many biophysical and socioeconomic factors have been used in quantitative analyses of wildfire risk. However, the importance and effects of socioeconomic factors in spatial modelling have been given inadequate attention. In this paper, we use different approaches to spatially model our data to examine the influence of human activity on wildfire ignition in the south west of the Madrid region, central Spain. We examine the utility of choropleth and dasymetric mapping with both Euclidean and functional distance surfaces for two differently defined wildfire seasons. We use a method from Bayesian statistics, the Weights of Evidence model, and produce ten predictive maps of wildfire risk: (1) five maps for a two-month fire season combining datasets of evidence variables and (2) five maps for the four-month fire season using the same dataset combinations. We find that the models produced from a choropleth mapping approach with spatial variables using Euclidian and functional distance surfaces are the best of the ten models. Results indicate that spatial patterns of wildfire ignition are strongly associated with human access to the natural landscape. We suggest the methods and results presented will be useful to optimize wildfire prevention resources in areas where human activity and the urban-forest interface are important factors for wildfire ignition.     

吴江市土地利用变化及其生态效应

利用1993、2000和2004年吴江市的遥感影像,在GIS和RS支持下,通过构建土地利用转移矩阵对土地利用变化进行分析,并对其产生的生态效应进行研究。结果表明,吴江市的耕地基底向建设用地基底转化,生态系统结构的多样性和均匀度降低,景观整体形状趋于规则;生态系统功能退化,耕地的减少以及建设用地面积的增加是导致总价值减少的主导力量,而水域生态服务价值的增加是阻止其显著减少的原因;水源涵养和废物处理功能贡献度最大,超过总价值的50%;汾湖镇所占生态服务价值比重最高,分别为24.2%、25.21%2、5.13%,桃源镇所占比重最低。     

基于多模式逆向水质模型的程海水位调控-水质响应预测研究

以云南省程海为例,基于CE-QUAL-W2计算平台开发了水动力-水质模型.由于程海现有的数据不足以支撑开发可靠的流域水文与污染物负荷模型,为弥补由此引起的水质模型边界条件缺失的限制,本研究提出了基于逆向模拟与遗传算法的多模式负荷-参数识别方法来实现对水质模型的校正和鲁棒校验.应用校验后的模型对程海不同水位调控情景的水质...     

牛栏江污染物源解析与空间差异性分析

牛栏江-滇池补水是缓解滇池生态用水短缺的重要工程,对牛栏江流域主要污染源与空间差异性的识别分析,将有助于进一步改善牛栏江的水质. 采用CFA(对应分析)对牛栏江流域污染源进行解析识别,结果表明流域内TN、NH₃-N(氨氮)等污染物主要来源于嵩明县境内,TP、氟化物等污染物主要来源于寻甸县境内. 在CFA分析的基础上,采用HCA(层次聚类分析)和SOM(自组织映射神经网络)对4个监测点、10种污染物指标进行分析,以识别空间分布的差异性和相似性,并且评价各指标的空间分布特征及监测点代表性. 结果表明:4个监测点中,TP、氟化物、砷化物、Vph(挥发酚)在寻甸县境内的七星桥污染最严重;TN、NH₃-N在牛栏江上游嵩明县境内的四营污染最重. 结合流域污染负荷调查可知,寻甸县的磷负荷最大,占流域总负荷的58.73%,七星桥的TP污染贡献大于其他3个监测点,与七星桥TP污染最为严重相符合. 该研究结果可为牛栏江流域实施进一步的分段治理提供决策支撑.      

The Dechlorination of H6CDD,OCDD and OCDF on an Alumina support: Elucidation of the isomer pattern by multi linear regression and thermodynamic data

The dechlorination of OCDD, OCDF and 1,2,3,4,7,8‐H₆CDD is studies on an alumina support impregnated with activated carbon, copper chloride and potassium chloride. There is a high correlation between the isomer pattern found after dechlorination and molecular structure properties. We also found a substantial correlation between the isomer pattern and the Gibbs free energy of formation of the individual isomers. This suggests a thermodynamically controlled process.     

Changes in wetland landscape patterns on Yinchuan Plain,China

Wetlands, with their many values and important functions, are precious resources. They have, however, undergone great changes during economic development and population growth. Relying on recent advances in remote sensing and geographic information system (GIS) techniques, this paper probes changes in wetland landscapes on Yinchuan Plain during 1978–2006. A series of remote sensing images was used to identify wetland landscape types. Landscape pattern indices, such as patch number, patch density, landscape shape, and Shannon's diversity, evenness, and contagion indices were calculated with GIS and landscape analysis software. Changes in wetland landscape patterns on Yinchuan Plain were analyzed. The analysis show that the total area of wetlands on Yinchuan Plain decreased from 391,540,239 m² in 1978 to 267,979,957 m² in 2006, a significant change over 28 years. The area of rivers and lakes has shrunk, and the area of paddies has increased consistently, with increasing wetland fragmentation and heterogeneity. The number of patches, patch density, and landscape shape index shows that wetland landscape patterns have undergone great changes. The landscape diversity, landscape evenness, and contagion indices indicate that wetland landscapes have become less heterogeneous. We discuss the causes of these changes and the sustainable development of wetland ecosystems.     

环鄱阳湖区城市化格局的空间分异分析

建立了城市化格局的单指标和复合指标测度体系,运用主成分分析法对环鄱阳湖区人口、经济、生活、基础设施和综合城市化格局的空间分异进行了分析。研究发现:1)人口和基础设施城市化率呈现环湖边缘区最大,核心区其次,外围区最小的倒U形式的规律;经济城市化率则呈现边缘区最高,外围区次之,核心区最低的规律;而生活城市化水平呈现核心区最高,边缘区其次,外围区最低的格局。2)随着距鄱阳湖体距离的增加,城市化复合水平呈现依次下降的规律。该结果表明鄱阳湖作为一个特殊地理事物,它的存在对该区城市经济发展的空间分异具有一定程度的影响。