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181.
The breeding habitat selection by houbara bustards in Mori, Xinjiang, China duringthe breeding seasons from April to June 1998-2000 was studied. Most of habitats chosen forbreeding were short sub-shrubby and open areas close to high bushy patches. The nesting re-males clearly prefer Iow covered areas and avoid densely covered and high vegetation sites. Thenumber of herb species was significantly smaller at nest sites than at randomly selected sites.Only the distance to the closest fox den contributed the most to discrimination between successfuland predated nests. The average distance to the closest fox den was significantly longer at suc-cessful nests than at depredated nests. Vegetative density, plant species richness, topography anddistance to the closest fox den are possibly the most important factors that determined the nestsites selection of houbara bustard. The displaying males clearly prefer Iow covered areas andavoid densely covered and high vegetation sites. The vegetation density and number of plant spe-cies at display sites was significantly lower than that at randomly selected sites. The average dis-tance to the closest bushy patch was significantly shorter at display sites than at random sites.Plant species richness, vegetative density, vegetative cover and distance to the bushy patches arepossibly the most important factors for the display sites selection of houbara bustard. 相似文献
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本文概述了“场地地震危险度评估专家系统”课题组6年工作的主要成果和智能辅助地震区划系统IASHES的组成及测试结果,着重叙述了潜辰源区两级划分的思想,A级潜在辰原区地震活动趋势估计和B级潜在震源区划分及震级上限判定所依据的专家知识,以及适用于专家系统的B级潜在震源区加权系数的确定方法。 相似文献
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Cairo City has a large number and different forms of Islamic archaeological sites, in particular, at El-Gammalia and El-Moez
streets, as well as Coptic archaeological sites, e.g. at Mari Gergis. Human interference and activities at these historical
areas resulted in flooding such sites’ foundations with domestic water, deteriorating its basal courses by salt weathering.
The 1992 earthquake is another natural environmental hazard severely affecting many of these sites. The aim of the current
study is to examine some factors (of bedrock and buildings) that are expected to control building susceptibility to damage
by earthquakes by taking 38 Islamic archaeological sites in the El-Gammalia area as a representative case study. Detailed
field recordings of site damage category before and after the quake and continued recording of damage features generated by
the 1992 quake over the last 14 years, measuring depth to sub-surface water, measuring buildings’ height before the quake
and bedrock sampling at these sites for geotechnical investigations were all considered for achieving this aim. The data has
been processed mathematically and graphically (using the Excel package) to examine the main factors responsible for building
susceptibility to damage by earthquakes. The selected archaeological sites give an excellent representation of the factors
controlling building susceptibility to damage by quakes; it is found that the sites with heights (before the quake) ranging
from 12 to 14 m are the most affected ones; the sites with the highest damage category before the quake were more susceptible
to more damage by the quake; the sites that had been built on alluvium soil were more affected than those built on the Eocene
limestone. The age of these sites has, to a small extent, indirect control on sites’ susceptibility to damage by the quake,
particularly in parts flooded with domestic water (i.e. affected by salt weathering). The depth to sub-surface water is an
effective parameter on sites’ basal courses (through salt weathering), which, indirectly, control a building’s susceptibility
to quakes, particularly where the depth of water ranges from 0.6 to 1.6 m in alluvium bedrock. The alluvium soil at the study
area has a liquid limit ranging from 62% to 82%, plastic limit from 37% to 86% and plasticity index from 26% to 46% and free
swelling from 27% to 81%. These geotechnical limits for such alluvium bedrock indicate that its clay minerals are mostly montmorrillonite. 相似文献
187.
Xiaojing Yao Liujia Chen Congcong Wen Liang Yang Tianhe Chi 《International journal of geographical information science》2018,32(5):980-1005
Spatial co-location pattern mining is employed to identify a group of spatial types whose instances are frequently located in spatial proximity. Current co-location mining methods have two limitations: (1) it is difficult to set an appropriate proximity threshold to identify close instances in an unknown region, and (2) such methods neglect the effects of the distance values between instances and long-distance instance effects on pattern significance. This paper proposes a novel maximal co-location algorithm to address these problems. To remove the first constraint, the algorithm uses Voronoi diagrams to extract the most related instance pairs of different types and their normalized distances, from which two distance-separating parameters are adaptively extracted using a statistical method. To remove the second constraint, the algorithm employs a reward-based verification based on distance-separating parameters to identify the prevalent patterns. Our experiments with both synthetic data and real data from Beijing, China, demonstrate that the algorithm can identify many interesting patterns that are neglected by traditional co-location methods. 相似文献
188.
Spatial co-location pattern mining of facility points-of-interest improved by network neighborhood and distance decay effects 总被引:1,自引:0,他引:1
Wenhao Yu Tinghua Ai Yakun He Shiwei Shao 《International journal of geographical information science》2017,31(2):280-296
The aim of mining spatial co-location patterns is to find the corresponding subsets of spatial features that have strong spatial correlation in the real world. This is an important technology for the extraction and comprehension of implicit knowledge in large spatial databases. However, existing methods of co-location mining consider events as taking place in a homogeneous and isotropic context in Euclidean space, whereas the physical movement in an urban space is usually constrained by a road network. Furthermore, previous works do not take the ‘distance decay effect’ of spatial interactions into account, which may reduce the effectiveness of the result. Here we propose an improved spatial co-location pattern mining method, including the network-constrained neighborhood and addition of a distance-decay function, to find the spatial dependence between network phenomena (e.g. urban facilities). The underlying idea is to utilize a model function in the interest measure calculation to weight the contribution of a co-location to the overall interest measure instance inversely proportional to the separation distance. Our approach was evaluated through extensive experiments using facility points-of-interest data sets. The results show that the network-constrained approach is a more effective method than the traditional one in network-structured space. The proposed approach can also be applied to other human activities (e.g. traffic accidents) constrained by a street network. 相似文献
189.
在世界遗产地旅游产业发展的动态背景下,运用偏离份额分析法和向量夹角法分别从产业结构的合理化和高级化两个视角衡量山东省曲阜市2006—2015年旅游产业结构的时序变化,测度曲阜市旅游产业结构变动对旅游经济发展的贡献。研究表明:曲阜市旅游产业有一定的结构优势但竞争力相对较弱,合理化水平有待提高;旅游产业结构的高级化水平虽然有升有降,但平均水平一直较高,表现出高位震荡的特征;旅游产业结构变动对旅游经济增长贡献度的均值为0.03,周期性震荡呈现收敛趋势,反映出曲阜市旅游经济发展趋于成熟。 相似文献
190.
运用Arc GIS空间分析、耦合分析方法研究新疆432处文化遗址的时空演变及人地关系。结果表明:(1)新疆文化遗址以集聚模式分布于4个遗址集聚带、12个组群,呈现出"空间组群、线(带)状分布"的空间格局,其空间分布格局主要受控于自然环境;(2)不同历史时期中央政权经略西域策略的改变使得新疆的经济和政治重心发生转移,文化遗址分布重心轨迹呈"北→南→北"演变的规律,其时间上的演变较多地受人文因素的控制;(3)从旧石器时代至近现代,新疆文化遗址的变化经历了萌芽、发展、上升、繁荣、下降、巅峰6个阶段,遗址的盛衰演化与历史时期自然气候环境的变化、人文要素的兴衰等有良好的耦合关系。在人地关系地域系统内部及系统与外界环境之间的各个要素组合优良时期,政权强盛,屯垦发展,丝路繁荣,气候适宜,文化遗址增长迅猛(如西汉、隋唐)。 相似文献