基于遗传算法的磁流变阻尼器模型参数识别

磁流变阻尼器是一种具有广阔应用前途的半主动控制装置,但其复杂的力学特性很难精确描述。非线性参数模型是一个相对简单并且能够很好地描述磁流变阻尼器力学特性的力学模型,但该模型既是非线性的、又是非解析的,参数识别十分困难。结合传统遗传算法良好的全局搜索能力和二分法可靠的收敛性,本文提出了一种改进的遗传算法——层次压缩遗传算法。对非线性参数模型的参数识别结果显示：层次压缩遗传算法简单可行,具有较高的识别精度。同时也验证了非线性参数模型描述磁流变阻尼器阻尼力特性的准确性。     

主体功能区划可利用土地资源的探讨——以芜湖市为例

在阐述主体功能区划可利用土地资源概念的基础上,结合芜湖市实际情况提出各指标项并具体给出算法,确定技术流程,然后借助GIS技术,实现实验结果。研究结果表明,市区的后备建设用地很少,三县相对来说较为充裕,三县之间的内部差距也较小。根据后备建设用地较少这一实际情况,该市应科学合理地制定土地利用相关规划,并实行最严格的用途管制。     

基于四叉树索引构建TIN的高效合成算法

不规则三角网(TIN)可以逼真的模拟地形表面,因此被广泛应用于地学领域。Delaunay三角剖分算法是构建TIN网的最优算法,该文对传统Delaunay三角网构建算法进行分析,提出了一种针对大规模离散数据点生成TIN的高效合成算法。该算法首先根据离散点的分布位置和密度对其进行四叉树区域划分;然后以每个叶子节点的边界四边形为凸包,采用逐点插入法构建三角网;最后采用顶点合并法自底向上合并具有相同父节点的4个子节点,生成Delaunay三角网。实验结果表明,该算法时间复杂度较低,有效提高了TIN网的构建效率。     

An optimization approach for sustainable development planning of savanna systems

A savanna system is a natural ecosystem in which the competition between grass and woody vegetation in a semi-arid rangeland should be maintained for its sustainable development. Finding an optimal management plan for obtaining maximum economic profit from raising cattle without loss of sustainability of the savanna system during a planning period is a great challenge for rangeland managers. In this study, we formulate the sustainable development planning of the savanna system as an optimal control model, in which maximization of the stocking rate of cattle during the planning period is chosen as the objective while sustainable development requirements are achieved through the constraints represented by the desired final state of the system. Using Pontryagin's maximum principle, the model is transformed into a two-point boundary-value problem with nonlinear differential equations that is then solved using an iterative approach. An example with a specified desired final state in a savanna system without fire is used to demonstrate the performance of the model and the algorithm. Numerical experiments show that the planning strategy obtained from the optimal control model achieves maximum economic profit from raising cattle during the planning period and simultaneously improves the resilience of the system and maintains sustainable development of the rangeland. The outcomes demonstrate that resilience, sustainable development and economic profit are consistent concepts in optimal management strategy for rangeland management.     

云阳宝塔滑坡监测的变形模式识别与分析

根据变形观测的位移矢量,识别变形体及其运动模式,是变形分析的一项重要内容。以往的作法是根据矢量作图、人工判断变形块体,然后选择适当的模式进行拟合。本文提出了一种在点位邻接拓扑关系加其他先验信息构成约束的识别思想及相应算法,从而可实现变形模式的自动识别。最后的算例说明了该算法的实现过程,有效性及潜在意义。     

基于MRF参数的纹理识别的线性规划法

介绍了基于MRF参数的线性规划法纹理识别的原理和单纯形算法。通过对7种从航空像片上采集的典型纹理的分类实验表明,平均正确识别率为0.94,平均正确拒绝率为0.92。     

复杂地表条件反射振幅一致性校正

通过对地表一致性数学物理模型的前提条件进行剖析,合理地确定了反射振幅一致性校正模型,并依据该模型及其实现条件提出使用共轭梯度方法在时间域对地震记录进行谱分解处理. 通过选择复杂地表条件地区的较为典型的地震记录进行资料处理,结果表明:采用所提出的方法可以有效地校正因复杂地表条件等因素对地震反射振幅而产生的影响. 在复杂地表条件及信噪比较低地区的地震资料处理中,该方法具有处理速度快、抗噪能力强及实际应用效果显著的优点.     

基于S波段双偏振雷达资料的降水粒子类型识别算法及应用

基于质量控制的S波段双偏振雷达格点化观测数据,利用模糊逻辑算法,结合降雨粒子散射和空间取向等特征建立了降水粒子类型识别算法,用于分析降水过程中降水粒子的空间分布情况及粒子类型的演变过程.该算法可以将降水粒子分为液态、冰态、混合态等不同种类,有助于发现影响降水多寡的云微物理关键结构.首先根据不同降水粒子的雷达回波特性得到...     

Landsat ETM＋数据的武汉市地表温度反演研究

以Landsat ETM＋为主要遥感数据源,辅助以气象数据资料,利用NDVI计算出植被覆盖率,继而计算出地表比辐射率,并利用单窗算法精确反演得到了武汉市2002年夏季地表温度。研究表明,武汉城市热岛由武昌、汉口、汉阳三大城区热岛构成,且几乎集中在城区;城区大热岛区中还存在多数热岛效应更为严重的＂岛中岛＂;武汉热岛分布与...     

A center-based modeling approach to solve the districting problem

This article deals with the districting problem arising in applications such as political districting, police patrol area delineation and sales territory design. The aim of districting is to group basic areal units into geographic districts such that some set of criteria are satisfied, with basic criteria being district balance, compactness and contiguity. This article proposes a center-based mixed-integer linear programming model to solve the districting problem. Given the central units of districts, the model optimizes weighted objectives of district balance and compactness while satisfying contiguous constraints on districts. The performance of the model was tested using three study areas with 297, 324 and 1297 areal units, respectively. Experimentation shows that, using the district centers identified by a multistart weighted K-medoids algorithm, the model instances can be solved optimally or near-optimally. Compared with local search-based algorithms, the center-based approach outperforms metaheuristics such as simulated annealing, variable neighborhood descent, iterative local search and old bachelor acceptance search in terms of solution quality.