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151.
152.
Economic transition in central and eastern Europe (CEE) has had a particularly strong impact on industrial cities and regions. Following their economic collapse, most of them are now confronted with serious problems such as high unemployment and vast ecological damage. The paper presents findings from a pan European research project that investigated the problems of these cities and regions as well as the strategies being adopted to cope with structural change. It examines the differences in approaches and addresses the question whether existing EU policy is suitable for supporting the redevelopment of old industrial cities and regions in CEE countries. The paper concludes with recommendations for future directions in policy making. 相似文献
153.
A multi-equation spatial econometric model,with application to EU manufacturing productivity growth 总被引:1,自引:0,他引:1
Bernard Fingleton 《Journal of Geographical Systems》2007,9(2):119-144
A multi-equation spatial econometric model is used to explain variations across EU regions in manufacturing productivity growth
based on recent theoretical developments in urban economics and economic geography. The paper shows that temporal and spatial
parameter homogeneity is an unrealistic assumption, contrary to what is typically assumed in the literature. Constraints are
imposed on parameters across time periods and between core and peripheral regions of the EU, with the significant loss of
fit providing overwhelming evidence of parameter heterogeneity, although the final model does highlight increasing returns
to scale, which is a central feature of contemporary theory.
相似文献
154.
Colin Robertson Trisalyn A. Nelson Barry Boots Michael A. Wulder 《Journal of Geographical Systems》2007,9(3):207-227
Research questions regarding temporal change in spatial patterns are increasingly common in geographical analysis. In this
research, we explore and extend an approach to the spatial–temporal analysis of polygons that are spatially distinct and experience
discrete changes though time. We present five new movement events for describing spatial processes: displacement, convergence,
divergence, fragmentation and concentration. Spatial–temporal measures of events for size and direction are presented for
two time periods, and multiple time periods. Size change metrics are based on area overlaps and a modified cone-based model
is used for calculating polygon directional relationships. Quantitative directional measures are used to develop application
specific metrics, such as an estimation of the concentration parameter for a von Mises distribution, and the directional rate
of spread. The utility of the STAMP methods are demonstrated by a case study on the spread of a wildfire in northwestern Montana.
相似文献
155.
Studies on small-world networks have received intensive interdisciplinary attention during the past several years. It is well-known
among researchers that a small-world network is often characterized by high connectivity and clustering, but so far there
exist few effective approaches to evaluate small-world properties, especially for spatial networks. This paper proposes a
method to examine the small-world properties of spatial networks from the perspective of network autocorrelation. Two network
autocorrelation statistics, Moran’s I and Getis–Ord’s G, are used to monitor the structural properties of networks in a process of “rewiring” networks from a regular to a random
network. We discovered that Moran’s I and Getis–Ord’s G tend to converge and have relatively low values when properties of small-world networks emerge. Three transportation networks
at the national, metropolitan, and intra-city levels are analyzed using this approach. It is found that spatial networks at
these three scales possess small-world properties when the correlation lag distances reach certain thresholds, implying that
the manifestation of small-world phenomena result from the interplay between the network structure and the dynamics taking
place on the network.
相似文献
156.
区域划分是依据人口和社会经济指标将行政统计单元或其他地理实体划分成若干个不同水平或类别的集合。由于大多数的人口和社会经济指标来源于面状数据-行政统计单元,常用的区域划分的空间聚类方法是基于面状数据的,本文通过分析现有面状数据的聚类算法特点和不足,进而提出一种新的算法,该方法提出将面状统计单元进行网格划分,引入基于网格密度聚类算法的思想,克服现有面状聚类的诸多缺点,打破行政区划的限制,更好地发现潜在信息。 相似文献
157.
158.
矿井导线网空间关系和操作的半序集模型 总被引:3,自引:1,他引:2
本文用单纯复形的半序关系和格的数学理论,对矿井导线网的空间关系和操作给予了形式的描述。导线网的细部用半序关系来表示,一般能回答导线网的包含、相邻、相接等空间关系问题,用格的理论能方便地实现导线网的交、并和查询等空间操作。对于非格的半序关系,通过增加新的元素构成格,用序的理论对导线网的结构进行形式描述,为导线网数据和拓扑结构的计算机存储和操作提供理论基础。 相似文献
159.
本文研究了城市给排水管网信息系统的数据结构及其建立方法,以及在微机上利用C语言进行城市给排水信息系统的设计,实现了部分空间分析功能。 相似文献
160.
Differences in trace metal concentrations among fluvial morphologic units and implications for sampling 总被引:2,自引:0,他引:2
This study examines the segregation of trace metals within and between fluvial morphologic units in sand-sized and finer
bed sediments in a cobble bed stream. The types of fluvial morphologic units sampled are low gradient riffles, high gradient
riffles, glides, eddy drop zones, lateral scour pools, attached bars, and detached bars. Three to nine samples were collected
from ten of each type of morphologic unit. All 12 metals show significantly different concentrations between some morphologic
units in sediments smaller than 2 mm. Eddy drop zones and attached bars consistently have the highest metal concentrations,
while low gradient riffles, high gradient riffles, and glides typically have the lowest concentrations. Metals showing the
greatest between-unit variability are Al, Cr, Fe, Cu, and Ti, followed by Co, Mn, and Pb, while Mg, Mn, V, and Zn display
relatively few differences between units. Lateral and longitudinal variations of metals within units are not significant,
and there was no consistent, predictable variation in metal concentrations with distance downstream. Results indicate that
metal studies in other gravel- and cobble-bed streams should include a reconnaissance survey to determine variations between
morphologic units, stratify sampling by morphologic unit, and analyze spatial autocorrelation to determine sample spacing.
Received: October 1997 · Accepted: 23 March 1998 相似文献