随机模拟在常州运河水质规划中的应用

以常州运河的水质规划为实例,讨论了确定性水质模型的随机模拟。讨论中引进了主观概率和客观概率的概念,用泰勒级数确定客观概率分布,用可能最大机率法估计主观概率分布,并给出了在实施不同规划方案时的水质概率曲线和水质达标的保证率。计算结果表明,使水质恶化的各种随机因素的作用不容忽视,各种水污染治理措施只能降低水质超标的风险水平。     

水环境模拟中多孔介质非均质性空间变异最优估计模型

在生产实践中,经常要求对含水介质渗透性参数的空间分布数值作出可靠的估计.如何利用已知数据对指定点处的渗透性参数作出令人满意的估计,历来是水文地质工作者和应用数学工作者都关心的问题.文章应用能够刻画区域化变量随机性与结构性特征的地质统计学的理论和方法对能够反映多孔介质非均质特性的参数进行了分析,通过分析结果得出了参数空间变异性局部最优估计模型--普通克里格法.     

两点校正法的正确选择

在应用两点校正中，计算相对偏差在选择浓度点上有不同选法：相对偏差计算公式也有不同选法，导致计算结果没有可比性。本文用校准曲线及相对偏差概念，论述了应用两点校正法校正校准曲线如何正确选择浓度点及计算公式。     

GA优化的湖泊富营养化评价的普适公式探讨

在适当设定富营养化指标的“本底值”情况下,当指标值用于对应“本底值”的相对值表示时,可采用S型曲线描述湖泊富营养化的发展程度,公式中的参数可视为与指标特性无关,采用遗传算法对公式参数优化,得到对多项指标均适用的富营养化程度的指数公式,并提出用广义模糊对比因子赋权新方法计算富营养化综合指数。该评价方法物理意义明确,计算简单,使用方便,具有普适性、可比性和实用性。     

西部地区经济发展与水环境质量的相关分析

认识经济发展与水环境污染的关系,以求西部地区经济与环境的协调发展。文章运用环境库兹涅茨理论和自回归分析模型,对1995～2004年我国西部地区人均GDP与废水排放量的分析,可知西部地区的人均GDP增加1%,则污水排放量增加0.582%,经济发展伴随着水环境质量的持续恶化,说明西部地区目前处于环境库兹涅茨曲线的左半部分。因此有必要加强对水环境的规制和治理,改善经济发展和水环境质量之间的这种两难关系。还表明自回归模型对于西部地区水环境质量的预测也是有效的。     

解析几何发展简史

解析几何已是一门重要的数学分支,对其发展过程的了解,会吸引人们对科学发现的 兴趣。本文就解析几何的产生过程作了比较详细的叙述,使人们看到了解析几何的巨大贡献。     

METHODOLOGIES FOR CALIBRATION AND PREDICTIVE ANALYSIS OF A WATERSHED MODEL1

ABSTRACT: The use of a fitted parameter watershed model to address water quantity and quality management issues requires that it be calibrated under a wide range of hydrologic conditions. However, rarely does model calibration result in a unique parameter set. Parameter nonuniqueness can lead to predictive nonuniqueness. The extent of model predictive uncertainty should be investigated if management decisions are to be based on model projections. Using models built for four neighboring watersheds in the Neuse River Basin of North Carolina, the application of the automated parameter optimization software PEST in conjunction with the Hydrologic Simulation Program Fortran (HSPF) is demonstrated. Parameter nonuniqueness is illustrated, and a method is presented for calculating many different sets of parameters, all of which acceptably calibrate a watershed model. A regularization methodology is discussed in which models for similar watersheds can be calibrated simultaneously. Using this method, parameter differences between watershed models can be minimized while maintaining fit between model outputs and field observations. In recognition of the fact that parameter nonuniqueness and predictive uncertainty are inherent to the modeling process, PEST's nonlinear predictive analysis functionality is then used to explore the extent of model predictive uncertainty.     

IMPACT OF COAL SURFACE MINING ON THREE OHIO WATERSHEDS - SURFACE-WATER HYDROLOGY1

ABSTRACT: A study was conducted to determine the effects of mining and reclaiming originally undisturbed watersheds on surface-water hydrology in three small experimental watersheds in Ohio. Approximately six years of data were collected at each site, with differing lengths of premining (Phase 1), mining and reclamation (Phase 2), and post-reclamation (Phase 3) periods. Mining and reclamation activities showed no consistent pattern iii base-flow, and caused slightly more frequent higher daily flow volumes. Phase 2 activities can cause reductions in seasonal variation in double mass curves compared with Phase 1. Restoration of seasonal variations was noticeably apparent at one site during Phase 3. The responses of the watersheds to rainfall intensities causing larger peak flow rates generally decreased due to mining and reclamation, but tended to exceed responses observed in Phase 1 during Phase 3. Natural Resources Conservation Service (NRCS) curve numbers increased due to mining and reclamation (Phase 2), ranging from 83 to 91. During Phase 3, curve numbers remained approximately constant from Phase 2, ranging from 87 to 91.     

洪水灾害评估体系研究

从系统论的观点出发，提出了洪水灾害系统的概念，并结合洪水灾害评估的特点，设计了洪水灾害评估体系的总体框架。     

重力式码头的震害预测

本文根据重力式码头的结构地震荷载计算和地震破坏的经验，建立了重力式码头的震害预测方法。并用此方法对烟台港的重力式码头进行了震害预测。