Influence of ridges on hydrographic parameters in the Southwest Indian Ocean

The objective of the paper is to use the data collected along two meridional sections (45° E and 57°30′ E) during the austral summer (January–March) 2004 to understand the influence of seabed topography across the Madagascar and Southwest Indian Ridges on hydrographic parameters. The study was supplemented by World Ocean Circulation Experiment (WOCE) Conductivity-Temperature-Depth data collected during February–March 1996 along 30° E, as well as Levitus climatology. A southward shift of 2° latitude (between 45° E and 57°30′ E) was recorded for the two predominant frontal structures, i.e., the Agulhas Return Front and Southern Subtropical Front, which is attributed to the influence of seabed topography on hydrographic parameters. No significant spatial variation of these fronts was noted between the 30° E and 45° E meridional sections. Between latitudes 31° S and 42° S, the temperature and salinity structures show deepening over the ridges. The Antarctic Circumpolar Current core was detected between 40°15′ S and 43° S.     

利用GPS技术的货物运输车辆路径问题的遗传算法研究

提出了具有时间窗的货物运输车辆路径问题，根据车辆装载GPS设备的特性，建立了该问题的数学模型，并设计了求解它的遗传算法，初步计算表明算法具有很好的性能。     

Climate change and sustainable development: towards dialogue

The consequences of climate change and sustainable development remaining as separate discourses are explored, both in general and in the Canadian context. One of these consequences is the difference in emission and economic development scenarios generated by the two groups. A second is that strategies to reduce greenhouse gas emissions are designed and assessed in a narrow technical context, divorced from the economic and social forces that underlie them. We identify the need for climate change and sustainable development to be represented in a more explicit manner in each other's research agendas, and for integrated assessment of climate change to incorporate alternative methodologies that complement global scale integrated assessment models. These methodologies should include greater involvement of stakeholders as partners with researchers in a shared learning experience.     

基于数值模拟的黄河下游不同情景溃堤洪水特性

The lower Yellow River still faces the threat of flood due to the unusual precipitation caused by global environmental change, river channel sedimentation, hidden danger in the dike and unfavorable river regime of ＂hanging river＂. According to the characteristics of the dike-break flood of the Yellow River, this paper has simulated, in six different scenarios, the dike-break flood routing by inputting the terrain data, typical historical flood data and land use data of study area to two-dimensional unsteady flow model. The results show that： firstly, the routing process of flood will occupy other rivers on the way and return to the rivers after reaching the lower reaches; secondly, in the same river reach, flood inundating area of north band is bigger than that at corresponding location of south bank under the same historical flood; thirdly, it is different in the degree of flood inundation in different regions due to different geographical locations in flood plain; fourthly, the area of mainstream where flood is deep and flow velocity is quick is relatively smaller, but the area of non-mainstream, where flood is shallow and flow velocity is slow, is relatively big; and finally, the possible influenced area of the dike-break flood is 141,948 km^2.     

基于改进遗传算法的多约束VRP求解

建立了多约束条件车辆路径问题的数学模型和求解流程.先采用最近插入法生成初始解,然后基于遗传算法和模拟退火算法改进初始解.实验结果表明:结合模拟退火与遗传算法求解车辆路径问题,可以在一定程度上解决遗传算法易"早熟收敛"问题,从而得到更优的解.     

由等高线计算水域体积

介绍由等高线计算水域体积的过程,分析了水下地形的特点,对应注意的问题进行了讨论并给出了解决方案和算法。     

基于六边形格网的城市内涝洪水演进方法研究

基于六边形格网建模的方式研究城市内涝洪水的演进过程,采用离散格网的方法,建立了一种基于规则多尺度离散格网的城市几何模型,通过三维地形测量数据和二维建筑物矢量数据的融合,形成了规则的地表格网模型,该模型同时考虑了城市地形和建筑等特殊阻拦体。在此基础上,提出了一种逆向的水流推演方法,由洪水的状态反算演进过程,即以洪水的水淹深度为基础,通过与出(排)水口的连通性,计算水淹的范围,由此实现了城市内涝洪水的模拟推演。试验表明,本文方法能够有效地实现城市内涝场景的演进推演,可以为城市防减灾与应急决策提供科学依据。     

A bidirectional path-finding algorithm and data structure for maritime routing

Route planning is an important problem for many real-time applications in open and complex environments. The maritime domain is a relevant example of such environments where dynamic phenomena and navigation constraints generate difficult route finding problems. This paper develops a spatial data structure that supports the search for an optimal route between two locations while minimizing a cost function. Although various search algorithms have been proposed so far (e.g. breadth-first search, bidirectional breadth-first search, Dijkstra’s algorithm, A^*, etc.), this approach provides a bidirectional dynamic routing algorithm which is based on hexagonal meshes and an iterative deepening A^* (IDA^*) algorithm, and a front to front strategy using a dynamic graph that facilitates data accessibility. The whole approach is applied to the context of maritime navigation, taking into account navigation hazards and restricted areas. The algorithm developed searches for optimal routes while minimizing distance and computational time.     

郯庐断裂带南段桴槎山韧性剪切带糜棱岩的变形条件和组分迁移系

本文对郯庐断裂带南段主干断裂典型的韧性剪切带进行了系统的剖析。从糜棱岩塑性变形的亚颗粒化、动态重结晶和矿物成分特征及岩石组分迁移变化等入手进行系统的研究工作,计算了岩石形成的温度、压力和流动应力和流变速率参数;模拟计算了岩石在剪切变形作用下的体积亏损及组分迁移的量值,探讨了变形－变质及流体的相关关系