Evaluating representation and scale error in the maximal covering location problem using GIS and intelligent areal interpolation     

Robert G. Cromley  Jie Lin  David A. Merwin 《International journal of geographical information science》2013,27(3):495-517

A common problem in location-allocation modeling is the error associated with the representation and scale of demand. Numerous researchers have investigated aggregation errors associated with using different scaled data, and more recently, error associated with the geographic representation of model objects has also been studied. For covering problems, the validity of using polygon centroid representations of demand has been questioned by researchers, but the alternative has been to assume that demand is uniformly distributed within areal units. The spatial heterogeneity of demand within areal units thus has been modeled using one of two extremes – demand is completely concentrated at one location or demand is uniformly distributed. This article proposes using intelligent areal interpolation and geographic information systems to model the spatial heterogeneity of demand within spatial units when solving the maximal covering location problem. The results are compared against representations that assume demand is either concentrated at centroids or uniformly distributed. Using measures of scale and representation error, preliminary results from the test study indicate that for smaller scale data, representation has a substantial impact on model error whereas at larger scales, model error is not that different for the alternative representations of the distribution of demand within areal units.  相似文献   

A simulation using a hybrid method for predicting fault zones ahead of a tunnel face     

In‐Mo Lee  Don‐Hee Kim 《国际地质力学数值与分析法杂志》2003,27(2):147-158

By monitoring and analysing three‐dimensional absolute displacement during tunnel excavation, it is possible to predict discontinuity zones ahead of tunnel face. This paper presents results of the three‐dimensional displacement obtained from three‐dimensional simulations using hybrid method for assessing the effect of discontinuity zones on monitoring data. The influence of fault zones and in situ initial stresses on the three‐dimensional tunnel movement is evaluated. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

基于O-TREE树表示的总线约束在VLSI/PCB布局中的应用     

李煜  张徐亮  虞厥邦 《成都信息工程学院学报》2005,20(3):291-296

布局是VLSI物理设计的关键环节，采用了O-TREE的编码表示方法来解决在超大规模集成电路布局中，具有预定义坐标结群约束模块的布局问题(简称PCA问题)。目前，存在一些成功的算法来解决PCA问题，然而，它们的算法有些复杂，有些耗时。由此提出了一种新的布局算法来解决这个问题，该算法是基于O-TREE结构，旨在减少总的运行时间且简便。通过对MCNC的标准例子ami33和ami49上仿真实验表明：与参考文献5提到的结果相比，新算法是可行的并且很有效。它不仅使芯片面积利用率得到改善，而且节约了一半以上的时间开销。  相似文献   

A simplified analysis method for piled raft and pile group foundations with batter piles     

Pastsakorn Kitiyodom  Tatsunori Matsumoto 《国际地质力学数值与分析法杂志》2002,26(13):1349-1369

A simplified method of numerical analysis has been developed to estimate the deformation and load distribution of piled raft foundations subjected to vertical, lateral, and moment loads, using a hybrid model in which the flexible raft is modelled as thin plates and the piles as elastic beams and the soil is treated as springs. Both the vertical and lateral resistances of the piles as well as the raft base are incorporated into the model. Pile–soil–pile, pile–soil–raft and raft–soil–raft interactions are taken into account based on Mindlin's solutions for both vertical and lateral forces. The validity of the proposed method is verified through comparisons with several existing methods for single piles, pile groups and piled rafts. Workable design charts are given for the estimation of the lateral displacement and the load distribution of piled rafts from the stiffnesses of the raft alone and the pile group alone. Additionally, parametric studies were carried out concerning batter pile foundations. It was found that the use of batter piles can efficiently improve the deformation characteristics of pile foundations subjected to lateral loads. Copyright © 2002 John Wiley & Sons, Ltd.  相似文献   

遥感卫星影像K-SVD稀疏表示去噪     

夏琴  邢帅  马东洋  莫德林  李鹏程  葛忠孝 《遥感学报》2016,20(3):441-449

常规的去噪方法在去除遥感卫星影像噪声时,往往会造成影像模糊和空间分辨率下降。本文将稀疏表示理论应用于遥感卫星影像去噪,提出了一种改进算法,能够保留低频信息不变,仅对影像的高频信息进行稀疏重建。算法核心是按照是否能够从过完备字典中选择较少原子进行稀疏表示的原则来区分高频信息中的有效信息和噪声。通过3组实验对改进算法与传统去噪方法进行对比检测,实验结果表明,改进算法在去除噪声的同时,能较好地突出影像的边缘和细节信息。  相似文献   

资源三号测绘卫星 DSM 与AST ER GDEM 精度对比分析--以高海拔山区为例     

张弛  葛莹  王冲  肖胜昌  李云婷  张骏源 《测绘工程》2016,25(8)

为了评价国产资源三号测绘卫星DSM数据质量,选取地貌类型丰富的云南省高海拔山区为试验样区,以1∶10 000实测地形图DEM为假定真值,以30m分辨率ASTER GDEM为评价参照,从高程精度和地形描述精度两方面着手,对国产资源三号测绘卫星DSM数据精确性进行分析。结果表明:国产资源三号测绘卫星DSM数据精度整体高于ASTER GDEM。  相似文献   

遥感云分类不确定性的多维混合熵模型评价     

吴浩  程志萍  史文中  周璐 《测绘科学》2016,41(5):50-54,176

针对遥感影像提取信息分类过程中存在随机不确定性和模糊不确定性两种噪声,影响分类结果的准确性问题,该文在多光谱遥感影像处理中,通过对传统的混合熵模型进行多维化改进,提出多维混合熵的不确定性评价模型。采用云算法对遥感影像进行解译分类,获取相应的不确定性模型参数计算出信息熵和模糊熵,从像元和类别两个尺度构建出遥感云分类不确定性的多维混合熵评价模型。结果表明,多维混合熵模型能够充分考虑多光谱遥感数据的多维性,可以从不同尺度对遥感分类的随机不确定性和模糊不确定性进行有效全面地评价。  相似文献   

三维室内地图表达方法研究与应用     

李强  夏青  邓晨 《地理信息世界》2016,(5):28-33

室内地图是室内空间信息的载体,是实现室内位置服务的基础。本文在当前研究和应用的基础上,从室内空间整体轮廓、单楼层和多楼层叠加3个层次对室内空间轮廓、室内通道要素、室内空间单元的表达方法进行了研究与实践,并以广州白云万达广场为例,基于Web前端3D引擎threejs实现了三维室内地图的表达和应用。通过该方法,用户可以对室内空间从整体到局部进行全面了解,满足室内地图应用和导航的需求,从而提高人们对室内空间的认知效果。  相似文献   

放养密度对西伯利亚杂交鲟摄食、生长以及肌肉组分的影响     

丁厚猛  李吉方  温海深  刘群  倪蒙  张墨  步艳  任源远  宋志飞 《海洋湖沼通报》2015,(1):79-84

研究了放养密度对西伯利亚杂交鲟幼鱼生长、摄食以及肌肉组分的影响。结果表明,经过80d的野外试验观察,发现在初始养殖密度分别为:3.9、6.3、8.7和11.0kg/m3的微流水环境中,高密度组(D组)和低密度组(A组)的死亡率、日摄食量、饵料系数(FCE)和摄食率差异显著(P0.05);西伯利亚杂交鲟幼鱼的最终体重、特定生长率(SGR)、日增重(DWG)都随着养殖密度的增大而降低,而单位水体日增重显著升高,最终体长和肥满度无显著差异(P0.05)。试验结束时,高密度组西伯利亚杂交鲟幼鱼肌肉中水分和灰分所占的比重越大,而在粗蛋白质含量和粗脂肪含量方面则表现出相反的趋势,但均无显著性差异。综合各种因素,建议西伯利亚杂交鲟幼鱼阶段的养殖密度为6~9kg/m3。  相似文献   

不同 AMDAR资料同化时间窗对台风“摩羯”预报影响研究          下载免费PDF全文

盛春岩  刘诗军  范苏丹  曲巧娜  丁锋  朱文刚  孙兴池 《山东气象》2021,41(4):11-25

2018年第14号台风“摩羯”对山东造成了大范围暴雨和大风天气,基于WRF（Weather Research and Forecasting）模式及其Hybrid-3DVAR混合同化预报系统,对Hybrid-3DVAR不同集合协方差比例和不同航空气象数据转发（aircraft meteorological data relay,以下简称AMDAR）资料同化时间窗对台风“摩羯”预报的影响进行了数值研究。结果表明：加大集合协方差比例对台风“摩羯”路径预报有较大影响和改进;当全部取来自集合体的流依赖误差协方差时,预报的台风路径最好,降水预报也最接近实况;AMDAR资料同化对于台风路径和降水预报也有正的改进作用,但加大集合协方差比例到100%时对台风路径预报影响更大;不同资料同化时间窗会影响同化的AMDAR资料数量,从而影响台风降水精细化预报;45 min同化时间窗的要素预报误差最小,对台风造成的强降水精细特征预报最接近实况;不同资料同化时间窗主要影响台风降水预报落区分布,对台风路径预报影响相对较小。  相似文献