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CA-Markov模型的空间尺度敏感性研究 被引量:23
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作者 赵冠伟 陈颖彪 +1 位作者 陈健飞 李江涛 《地理科学》 CSCD 北大核心 2011年第8期897-902,共6页
以广州市花都区为研究区,研究利用CA-Markov模型进行土地利用变化模拟的空间尺度敏感性特征,结论如下:①元胞尺寸的选择会明显影响模拟结果,元胞尺寸越大,模拟结果精度越低。模型中存在元胞尺寸的阈值,当元胞尺寸超出该阈值时,模拟结果... 以广州市花都区为研究区,研究利用CA-Markov模型进行土地利用变化模拟的空间尺度敏感性特征,结论如下:①元胞尺寸的选择会明显影响模拟结果,元胞尺寸越大,模拟结果精度越低。模型中存在元胞尺寸的阈值,当元胞尺寸超出该阈值时,模拟结果的精度急剧下降,因此对于元胞尺寸的选择必须要慎重。②邻域类型的选择也会对模拟结果产生影响。采用3×3冯诺依曼邻域的模拟结果会比3×3摩尔邻域和5×5摩尔邻域生成更多的斑块数量和更高的斑块密度,但是模拟结果的Kappa系数值相差不大。 展开更多
关键词 空间尺度 空间尺度敏感 CA-Markov 土地利用
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流域侵蚀产沙的尺度变异规律研究 被引量:14
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作者 唐政洪 蔡强国 许峰 《中国水土保持科学》 CSCD 2004年第1期56-61,共6页
侵蚀产沙的尺度变异规律 ,是当今土壤侵蚀研究的前沿 ,它涉及的研究范围广泛 ,小到土壤颗粒 ,大到全球气候变化与碳循环过程。特别是不同尺度流域之间侵蚀产沙和输移 ,究竟有什么样的内在联系 ,小流域所获得的研究成果是否能推广应用到... 侵蚀产沙的尺度变异规律 ,是当今土壤侵蚀研究的前沿 ,它涉及的研究范围广泛 ,小到土壤颗粒 ,大到全球气候变化与碳循环过程。特别是不同尺度流域之间侵蚀产沙和输移 ,究竟有什么样的内在联系 ,小流域所获得的研究成果是否能推广应用到大中流域 ,已成为迫切需要解决的重要科学问题。有关流域侵蚀产沙与输移过程随流域尺度复杂变化的研究 ,国际上刚刚开始 ,国内有关流域尺度研究主要涉及于水文学领域的一些尺度研究 ,关于流域侵蚀产沙与输移过程随流域尺度复杂变化的研究不多。作者对国外当前土壤侵蚀模型的最新进展进行了综述 ,并对侵蚀产沙的尺度变异规律进行了分析。由于具有GIS强大的空间数据管理和分析能力 ,它将在流域侵蚀产沙尺度变异这一侵蚀产沙的问题研究中发挥重要作用。 展开更多
关键词 流域侵蚀 产沙现象 尺度变异规律 空间尺度性 产沙预报 尺度问题
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城市体系空间结构研究进展与展望 被引量:3
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作者 赵璐 《开发研究》 2023年第2期28-36,共9页
结合城市体系空间结构研究从古典区位论到关系区位论、从地方空间到流动空间、从等级结构到网络体系等阶段性演进,结合已有研究主要进展以及今后拓展重要方面,从研究维度、广度、深度、方法四个方面论述城市体系空间结构的定量测度,并... 结合城市体系空间结构研究从古典区位论到关系区位论、从地方空间到流动空间、从等级结构到网络体系等阶段性演进,结合已有研究主要进展以及今后拓展重要方面,从研究维度、广度、深度、方法四个方面论述城市体系空间结构的定量测度,并结合美国、日本、荷兰等发达国家空间战略规划关注重点从空间邻近性到网络连接性的转变,立足中国情景以及构建双循环新发展格局的战略要求,从等级化和网络化协同发展的视角,提出我国城市体系空间结构布局优化的方向展望。 展开更多
关键词 城市体系空间结构 反身的多尺度空间 关系网络 区域一体化
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纹理的不变性特征和识别性能的视觉心理学研究
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作者 刘建清 徐琪 《兰州石化职业技术学院学报》 2016年第4期32-36,共5页
设计了三个视觉心理学实验,对人眼识别纹理过程中是否也提取了不变性的特征、以及目前的计算机识别算法的性能是否超过人眼视觉系统的纹理识别性能问题进行了实验比较,结果发现:(1)几种计算机识别算法的不变性性能与人类视觉系统的纹理... 设计了三个视觉心理学实验,对人眼识别纹理过程中是否也提取了不变性的特征、以及目前的计算机识别算法的性能是否超过人眼视觉系统的纹理识别性能问题进行了实验比较,结果发现:(1)几种计算机识别算法的不变性性能与人类视觉系统的纹理不变性性能基本上是一致的;(2)人类视觉系统对纹理识别具有旋转不变性。纵观人类视觉系统,单独的数字"6"和"9"认知区别很明显,一旦它们各自随机排列,形成纹理图像后,人类视觉系统会判断为同一纹理;(3)纹理特征由物体表面所展现,它取决于视觉分辨率。观测条件在某些设定情形下,人眼视觉系统纹理特征的空间尺度,其缩放尺度不变的范围大约为2.3倍;(4)一些计算机纹理分类算法的性能在限定条件下(如多尺度纹理斑块特征方法和Gabor滤波器方法),能够达到甚至超过人类视觉系统对纹理的识别能力。 展开更多
关键词 视觉心理学 纹理特征 旋转不变 空间尺度不敏感 不变
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冲击地压预测的煤岩变形局部化方法 被引量:9
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作者 潘一山 宋义敏 +2 位作者 朱晨利 任何 许海亮 《煤炭学报》 EI CAS CSCD 北大核心 2023年第1期185-198,共14页
冲击地压预测是冲击地压防治的前提和基础,是冲击地压研究中的一个重要内容,针对目前冲击地压前兆和冲击地压孕育过程之间内在的本质联系不清问题,从煤岩变形破坏的固有特征及冲击地压的失稳问题本质出发,借鉴经典力学中的能量原理,提... 冲击地压预测是冲击地压防治的前提和基础,是冲击地压研究中的一个重要内容,针对目前冲击地压前兆和冲击地压孕育过程之间内在的本质联系不清问题,从煤岩变形破坏的固有特征及冲击地压的失稳问题本质出发,借鉴经典力学中的能量原理,提出了以煤岩变形局部化为前兆的冲击地压预测方法。根据虚位移原理和稳定性理论,推导并得到了冲击地压发生临界条件和煤岩变形局部化发生条件,分析煤岩变形局部化与冲击地压内在联系。采用梯度塑性理论,通过引入内部长度参数,构建煤岩变形局部化模型,分析了变形局部化带宽带的影响因素。给出了测量内部长度参数的实验方法,对变形破坏向某一区域集中,且集中区具有一定尺度的现象进行理论解析。根据变形局部化的时空演化特点,引入描述变形局部化的空间聚集性、梯度显著性和曲率显著性指标,从“时间演化”属性和“结构演化”属性对变形局部化状态进行识别。对变形局部化预测方法进行初步的应用研究,分别采用实验的声发射数据和现场的微震数据,预测煤岩试件破坏区域和煤矿冲击地压危险区域。研究表明:煤岩变形局部化开始条件和冲击地压发生的临界条件相同,即冲击地压孕育演化过程和煤岩变形局部化的过程具有一致性;煤岩变形局部化带宽度与材料内部长度参数和煤岩冲击能指数有关,随着材料内部长度增大,变形局部化带宽度线性增大,随着煤岩冲击能指数增大,变形局部化带宽度非线性减小;根据实验和现场初步应用结果,表明空间聚集性、梯度显著性和曲率显著性指标能够描述和追踪变形局部化时空演化特征,变形局部化预测冲击地压危险区域方法具有可行性。 展开更多
关键词 冲击地压 预测预报 变形局部化 空间聚集 空间尺度显著
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Spatial Scale Effects of Water Erosion Dynamics:Complexities, Variabilities, and Uncertainties 被引量:2
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作者 WEI Wei CHEN Liding +2 位作者 YANG Lei FU Bojie SUN Ranhao 《Chinese Geographical Science》 SCIE CSCD 2012年第2期127-143,共17页
Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evalua... Severe water erosion is notorious for its harmful effects on land-water resources as well as local societies. The scale effects of water erosion, however, greatly exacerbate the difficulties of accurate erosion evaluation and hazard control in the real world. Analyzing the related scale issues is thus urgent for a better understanding of erosion variations as well as reducing such erosion. In this review article, water erosion dynamics across three spatial scales including plot, watershed, and regional scales were selected and discussed. For the study purposes and objectives, the advantages and disadvantages of these scales all demonstrate clear spatial-scale dependence. Plot scale studies are primarily focused on abundant data collection and mechanism discrimination of erosion generation, while watershed scale studies provide valuable information for watershed management and hazard control as well as the development of quantitatively distributed models. Regional studies concentrate more on large-scale erosion assessment, and serve policymakers and stakeholders in achieving the basis for regulatory policy for comprehensive land uses. The results of this study show that the driving forces and mechanisms of water erosion variations among the scales are quite different. As a result, several major aspects contributing to variations in water erosion across the scales are stressed: differences in the methodologies across various scales, different sink-source roles on water erosion processes, and diverse climatic zones and morphological regions. This variability becomes more complex in the context of accelerated global change. The changing climatic factors and earth surface features are considered the fourth key reason responsible for the increased variability of water erosion across spatial scales. 展开更多
关键词 water erosion spatial variation scale effect driving force UNCERTAINTY COMPLEXITY
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Multi-Embed Nonlinear Scale-Space for Image Trust Root Generation 被引量:1
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作者 Lizhao Liu Wentu Gao +3 位作者 Jian Liu Huayi Yin Huarong Xu Shunzhi Zhu 《China Communications》 SCIE CSCD 2016年第11期170-179,共10页
An image trust root is a special type of soft trust root for trusted computing. However,image trust root generation is difficult,as it needs a corresponding stable logic feature generation model and algorithm for dyna... An image trust root is a special type of soft trust root for trusted computing. However,image trust root generation is difficult,as it needs a corresponding stable logic feature generation model and algorithm for dynamical and sustained authentication. This paper proposes a basic function of constructing new scale-spaces with deep detecting ability and high stability for image features aimed at image root generation. According to the heat distribution and spreading principle of various kinds of infinitesimal heat sources in the space medium,a multi-embed nonlinear diffusion equation that corresponds to the multi-embed nonlinear scale-space is proposed,a HARRIS-HESSIAN scale-space evaluation operator that aims at the structure acceleration characteristics of a local region and can make use of image pixels' relative spreading movement principle was constructed,then a single-parameter global symmetric proportion(SPGSP) operator was also constructed. An authentication test with 3000 to 5000 cloud entities shows the new scale-space can work well and is stable,when the whole cloud has 5%-50% behavior with un-trusted entities. Consequently,it can be used as the corresponding stable logic feature generation model and algorithm for all kinds of images,and logic relationships among image features for trust roots. 展开更多
关键词 image trust root SCALE-SPACE diffusion equation evolution operator feature detection
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Fundamental Theories of Spatial Similarity Relations in Multi-scale Map Spaces 被引量:18
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作者 YAN Haowen 《Chinese Geographical Science》 SCIE CSCD 2010年第1期18-22,共5页
Similarity relation is one of the spatial relations in the community of geographic information science and cartography.It is widely used in the retrieval of spatial databases, the recognition of spatial objects from i... Similarity relation is one of the spatial relations in the community of geographic information science and cartography.It is widely used in the retrieval of spatial databases, the recognition of spatial objects from images, and the description of spatial features on maps.However, little achievements have been made for it by far.In this paper, spatial similarity relation was put forward with the introduction of automated map generalization in the construction of multi-scale map databases;then the definition of spatial similarity relations was presented based on set theory, the concept of spatial similarity degree was given, and the characteristics of spatial similarity were discussed in detail, in-cluding reflexivity, symmetry, non-transitivity, self-similarity in multi-scale spaces, and scale-dependence.Finally a classification system for spatial similarity relations in multi-scale map spaces was addressed.This research may be useful to automated map generalization, spatial similarity retrieval and spatial reasoning. 展开更多
关键词 similarity relation spatial relation multi-scale map spaces
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空间信息全球惟一编码GeoID模型初探 被引量:9
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作者 程承旗 宋树华 +2 位作者 濮国梁 万元嵬 董芳 《测绘科学》 CSCD 北大核心 2010年第6期73-75,264,共4页
为了解决由于不同数据模型中同一空间实体的编码不惟一而导致数据共享困难以及标识的静态性和无空间位置等问题,本文提出了基于全球剖分格网的空间信息全球惟一编码模型(GeoID),并设计了该编码模型的系统架构,试图实现全球连续的、多层... 为了解决由于不同数据模型中同一空间实体的编码不惟一而导致数据共享困难以及标识的静态性和无空间位置等问题,本文提出了基于全球剖分格网的空间信息全球惟一编码模型(GeoID),并设计了该编码模型的系统架构,试图实现全球连续的、多层次空间信息的惟一标识。通过对遥感影像中的空间实体进行了编码探讨,结果表明空间信息全球惟一编码模型将大大加快信息的查询与检索速度。 展开更多
关键词 全球剖分格网 GEOID 空间尺度 可分配 域码 最小外包面片
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区域地理教学中的综合思维探究
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作者 申玉铭 许欣 《中学地理教学参考》 北大核心 2022年第13期34-38,共5页
区域地理教学是地理教学的重要组成部分,教学过程中要注重培养学生的地理综合思维,进而引导其全面、系统地认识和解析各种自然与人文地理现象。文章结合相关案例,从空间尺度性思维、系统整体性思维、格局特征性思维、过程动态性思维、... 区域地理教学是地理教学的重要组成部分,教学过程中要注重培养学生的地理综合思维,进而引导其全面、系统地认识和解析各种自然与人文地理现象。文章结合相关案例,从空间尺度性思维、系统整体性思维、格局特征性思维、过程动态性思维、机理复杂性思维五个视角对综合思维进行探讨,并提出区域地理教学中运用综合思维解决具体区域问题的视角和教学策略。 展开更多
关键词 综合思维 空间尺度性 系统整体 格局特征 过程动态 机理复杂
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Scale dependence in the phylogenetic relatedness of alien and native taxa 被引量:2
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作者 Chris M.McGrannachan Gillis J.Horner Melodie A.McGeoch 《Journal of Plant Ecology》 SCIE CSCD 2020年第5期601-610,共10页
Aims Darwin’s naturalization hypothesis proposes that successfully established alien species are less closely related to native species due to differences in their ecological niches.Studies have provided support both... Aims Darwin’s naturalization hypothesis proposes that successfully established alien species are less closely related to native species due to differences in their ecological niches.Studies have provided support both for and against this hypothesis.One reason for this is the tendency for phylogenetic clustering between aliens and natives at broad spatial scales with overdispersion at fine scales.However,little is known about how the phylogenetic relatedness of alien species alters the phylogenetic structure of the communities they invade,and at which spatial scales effects may manifest.Here,we examine if invaded understorey plant communities,i.e.containing both native and alien taxa,are phylogenetically clustered or overdispersed,how relatedness changes with spatial scale and how aliens affect phylogenetic patterns in understorey communities.Methods Field surveys were conducted in dry forest understorey communities in south-east Australia at five spatial scales(1,20,500,1500 and 4500 m2).Standardized effect sizes of two metrics were used to quantify phylogenetic relatedness between communities and their alien and native subcommunities,and to examine how phylogenetic patterns change with spatial scale:(i)mean pairwise distance and(ii)mean nearest taxon distance(MNTD).Important Findings Aliens were closely related to each other,and this relatedness tended to increase with scale.Native species and the full community exhibited either no clear pattern of relatedness with increasing spatial scale or were no different from random.At intermediate spatial scales(20-500 m2),the whole community tended towards random whereas the natives were strongly overdispersed and the alien subcommunity strongly clustered.This suggests that invasion by closely related aliens shifts community phylogenetic structure from overdispersed towards random.Aliens and natives were distantly related across spatial scales,supporting Darwin’s naturalization hypothesis,but only when phylogenetic distance was quantified as MNTD.Phylogenetic dissimilarity between aliens and natives increased with spatial scale,counter to expected patterns.Our findings suggest that the strong phylogenetic clustering of aliens is driven by human-mediated introductions involving closely related taxa that can establish and spread successfully.Unexpected scale-dependent patterns of phylogenetic relatedness may result from stochastic processes such as fire and dispersal events and suggest that competition and habitat filtering do not exclusively dominate phylogenetic relationships at fine and coarse spatial scales,respectively.Distinguishing between metrics that focus on different evolutionary depths is important,as different metrics can exhibit different scale-dependent patterns. 展开更多
关键词 alien species community phylogenetics Darwin’s naturalization hypothesis spatial scale phylogenetic beta diversity
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Exploiting a depth context model in visual tracking with correlation filter
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作者 Zhao-yun CHEN Lei LUO +2 位作者 Da-fei HUANG Mei WEN Chun-yuan ZHANG 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2017年第5期667-679,共13页
Recently correlation filter based trackers have attracted considerable attention for their high computational efficiency. However, they cannot handle occlusion and scale variation well enough. This paper aims at preve... Recently correlation filter based trackers have attracted considerable attention for their high computational efficiency. However, they cannot handle occlusion and scale variation well enough. This paper aims at preventing the tracker from failure in these two situations by integrating the depth information into a correlation filter based tracker. By using RGB-D data, we construct a depth context model to reveal the spatial correlation between the target and its surrounding regions. Furthermore, we adopt a region growing method to make our tracker robust to occlusion and scale variation. Additional optimizations such as a model updating scheme are applied to improve the performance for longer video sequences. Both qualitative and quantitative evaluations on challenging benchmark image sequences demonstrate that the proposed tracker performs favourably against state-of-the-art algorithms. 展开更多
关键词 Visual tracking Depth context model Correlation filter Region growing
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