Knot Placement of B-spline Curves with Equally Spaced Geometric Information

受每个节点区间应该具有相同建模能力的启发,提出一种基于几何信息均分的B样条曲线节点设置算法.首先放置少量节点,以每个节点区间具有相等的几何信息量; 准则来确定节点的位置;为了提高样条的建模能力,根据上一次迭代中的拟合误差确定加细节点区间并使新节点均分该节点区间的几何信息.该算法可以快速有效地; 得到用户指定精度的逼近曲线.通过对一些具有不同几何复杂度的实例进行实验的结果表明,文中算法是有效的;与现有的2种算法相比,; 该算法在相同控制顶点的情况下能够得到更高精度的逼近结果.Motivated by the observation that each knot interval should be of the; same modeling ability, a knot placement algorithm based on equally; spaced geometric information for B-spline curves is proposed. In the; algorithm, a few of knots are determined according to the principle that; each knot interval is of the same amount of geometric information at the; initial iteration. In order to improve the modeling ability of the; B-splines, the knot interval needed to be refined is determined by the; last fitting errors and the new knot inserted is placed to equally space; the accumulated geometric information in the knot interval. Via the; adaptive knot placement algorithm, approximated curve with specified; tolerance can be produced rapidly and efficiently. Several models with; distinct geometric complexities are tested to demonstrate the efficacy; of our algorithm in fitting curves. Comparing to other two available; methods, more accurate results can be obtained by our method with the; same number of control points.国家自然科学基金; 福建省自然科学基金; 中央高校基本科研业务费专项资

A case study of cumulative effects assessment for harbor planning in China

累积影响评价是战略环境评价的主要方法和重要内容之一,但目前还缺乏通用的评价程序和方法。通过识别港口规划的累积影响源和途径,建立了基于水动力数值模型的累积影响评价的量化评估和分析框架。以厦门港嵩屿港区规划为例,通过对海湾纳潮量及各敏感点流速的模拟,计算淤积量及其分布变化,进而推测海域水质和底质变化,并分析了由此引起的海洋生物群落的变化趋势。通过比较不同岸线方案的累积影响,为港区岸线优选提供了科学判据。实践表明,该方法框架综合运用定量预测和定性分析手段,其结果能为港口规划的战略环境评价提供科学依据。 【英文摘要】 Cumulative effects assessment (CES) has become an important approach and also a key component of the strategic environmental assessment due to the increased recognition that most significant environmental changes are results of combined effects of many individual impact factors. Analyzing combined environmental effects is simple in principle but difficult in practice due to a lack of simple and effective CES methods and procedures. The paper presents a case of CIE for the harbor planning project for Songyu ..

The Application of Geographic Information System (GIS) in the Marine Water Quality Numerical Model

将地理信息系统（gIS）强大的地图处理能力以及数据分析功能应用于水质模型的前期建立以及后期数据输出查询中.这样大大缩短了模型建模周期，提高了模型精度，并且应用地理信息系统特有的地图与数据库相连结的功能，使得在地图上查询模拟结果成为现实.With the use of the functions (such as map treatment and data analysis) of Geographic Information System (GIS) in the water quality model, the model developing period is cut short, and on the other hand, the integration of map and data make it possible to inquire the simulated result on map through computer.In this way,the result of simulation is more accurate and visible

The Effect Evaluation of Coastal Engineering to Hydrodynamics a Numerical Modelling Approach

为评估海洋工程尤其是围海工程对海洋水动力环境及港口淤积效应的影响,本研究在厦门港建立了成熟的三维水动力数学模型,采用具有二次精度的六节点三角形单元,并利用粗细网格共存及多套网格一次剖分的非结构化网格技术模拟和预测了海洋工程前后水动力环境的变化情况.通过对嵩屿集装箱港区规划岸线进行环境影响评价的实践,证明了本模型可以为海洋工程的可行性研究及环境影响评价提供科学支撑.In order to evaluate the effect of coastal engineering on hydrodynamics,a robust three-dimensional hydrodynamic numerical model with 6-node triangular element and two order shape function is developed.This model can simulate and predicate the hydrodynamics variation caused by the engineering construct based on the unconstruct grid meshing technology.The application of this model to the EIA of Songyu harbor project shows it can be implemented to the feasible and EIA research of the marine engineering

空间物理学科发展战略研究

空间物理学是人类进入空间时代后迅速发展起来的一门新兴的多学科交叉的前沿基础学科。其将太阳和太阳风控制的日球层空间作为一个系统，研究太阳/太阳风与行星/彗星的上层大气、电离层、磁层乃至星际介质之间的相互作用。空间物理学从本质上讲是一门实验科学，空间物理探测是空间物理学发展的基础。进入新世纪，随着空间基础设施和人类高技术活动的日益频繁，空间物理学进入新的发展阶段，强调科学与应用的密切结合。近年来，空间物理学取得了一系列重要进展。本文对接国家自然科学基金委地球科学部“宜居地球−地球系统科学”的顶层战略设计，梳理总结近年来空间物理各学科发展动态和趋势，凝练中国空间物理学未来发展的重点领域，优化学科布局，推进空间物理各学科的高质量发展