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1.
The purpose of the paper is to determine if different generating processes produce cellular networks with distinctive contact number properties. Properties resulting from patterns produced by three generating processes, the Poisson, the compound negative binomial, and the “Smalley,” are examined in detail. The implications of the findings for the analysis of empirical cellular networks are discussed.  相似文献   

2.
Baseline models have been used in the analysis of social networks as a way to understand how empirical networks differ from “random” ones. For the purposes of social network analysis, a “random” network is one chosen—at random—from a population of possible graphs derived from a given generating function. Although these principled hypothesis tests have a long history, many of their properties and extensions to multiple data structures—here, specifically two‐mode data—have been overlooked. This article focused on applications of different baseline models to two data sets: donations and voting of the 111th U.S. Congress, and organizations involved in forums on watershed policy in San Francisco, USA. Tests using each data set, but with different baseline reference distributions, will illustrate the range of possible questions baseline models can address and the differences between them. The ability to apply different models and generate a constellation of results provides a deeper understanding of the structure of the system.  相似文献   

3.
Landscape connectivity networks are composed of nodes representing georeferenced habitat patches that link together based on a species’ maximum dispersal distance. These static representations cannot capture the complexity in species dispersal where the network of habitat patch nodes changes structure over time as a function of local dispersal dynamics. Therefore, the objective of this study is to integrate geographic information, complexity, and network science to propose a novel Geographic Network Automata (GNA) modeling approach for the simulation of dynamic spatial ecological networks. The proposed GNA modeling approach is applied to the emerald ash borer (EAB) forest insect infestation using geospatial data sets from Michigan, U.S.A. and simulates the evolution of the EAB spatiotemporal dispersal network structures across a large regional scale. The GNA model calibration and sensitivity analysis are performed. The simulated spatial network structures are quantified using graph theory measures. Results indicate that the spatial distribution of habitat patch nodes across the landscape in combination with EAB dispersal processes generate a highly connected small-world dispersal network that is robust to node removal. The presented GNA model framework is general and flexible so that different types of geospatial phenomena can be modeled, providing valuable insights for management and decision-making.  相似文献   

4.
Policy Networks as Collective Action   总被引:1,自引:0,他引:1  
An important contribution to the policy sciences, and to interorganizational research in particular, has been the introduction of the so-called policy network approach. Despite the fact that this approach has produced a multitude of concepts, it still lacks a theoretical scaffold. In this article it is argued that simply to refer to something called "network theory" is an unsatisfactory solution. It is suggested that one way of advancing the policy network approach is to apply collective action theory and explicitly regard different empirical appearances of network concepts as expressions of collective action. Six tentative building blocks of such a theory are suggested. It is further argued that the policy network approach would benefit from incorporation into a broader analytical framework such as the Institutional Analysis and Development framework. Finally, it is concluded that such an incorporation would advance our ability to understand the processes of policymaking and thus to fulfill one of the old commitments of policy analysis, namely to contribute to the refinement of policymaking processes in society.  相似文献   

5.
国外区域经济研究的一个新趋势——区域经济网络研究   总被引:1,自引:0,他引:1  
现代区域经济发展呈现出网络化的趋势。国外区域经济学者将复杂网络理论和方法引入到区域经济学中,逐渐开拓出区域经济网络研究这个新领域,形成了解释区域经济现象和揭示区域经济规律的网络分析路径。目前,国外的研究工作主要是运用复杂网络理论和分析方法,对区域经济中的各类网络进行规范的定义和描述,研究这些网络的形成与演化,揭示区域经济增长和发展中的网络效应,分析知识、技术等要素在网络中的流动和扩散。  相似文献   

6.
The Advocacy Coalition Framework (ACF) is a prominent approach to investigate the formation of coalition and their impact on policy outputs. Although the ACF combines both the network structures of a political process with actors' values and belief systems, most empirical tests focus mainly on beliefs rather than network structures. Considering a relational approach makes particular sense when one wants to investigate the structural patterns of a subsystem and to assess coalition formation and maintenance. The author therefore proceeds by taking two steps to study the existence of coalitions, power relations, and policy preferences: first, social network analysis frames the empirical study of network structures, based on the assumption that common beliefs are reflected in relations among actors involved in policy processes. Second, using a sophisticated mathematical algorithm, the multicriteria analysis furnishes a systematic evaluation of the elite's belief system. This methodological combination constitutes the added value of this research and allows for testing to establish if common beliefs are reflected in network structures.  相似文献   

7.
基于企业网络视角的城市网络研究进展与展望   总被引:4,自引:0,他引:4  
随着生产分割程度的不断加深,企业网络空间增长已经成为城市网络生长发育的重要驱动力量。近30年来,基于企业网络视角的城市网络研究日益增多,在链接关系及时空过程、价值生产空间格局、外部经济及其空间差异、规划实践及治理模式四个方面取得了重要进展。本文在梳理城市网络发展脉络的基础上,从多维视角提出了基于企业网络视角的城市网络理论体系研究框架。总体来看,基于企业网络视角的城市网络研究还处于起步发展阶段。围绕完善理论体系建设,未来研究应着力在5个方面取得进展:城市网络分析技术方法的发展完善、城市网络多维度时空过程的综合比较研究、城市网络发育过程的微观机理解析、城市网络演化模式理论模型研制、城市网络的治理模式和政策框架研究。  相似文献   

8.
Measuring the Structure of Road Networks   总被引:8,自引:0,他引:8  
Spatial networks display both topologic and geometric variations in their structure. This study investigates the measurement of a road network structure. Existing measures of heterogeneity, connectivity, accessibility, and interconnectivity are reviewed and three supplemental measures are proposed, including measures of entropy, connection patterns, and continuity. The proposed measures were applied to 16 test networks, which were derived from four idealized base networks: 90°, 45°, 30°, and completely connected. The results show that the differentiated structures of road networks can be evaluated by the measure of entropy; predefined connection patterns of arterial roads can be identified and quantified by the measures of ringness, webness, beltness, circuitness, and treeness. A measure of continuity evaluates the quality of a network from the perspective of travelers. Proposed measures could be used to describe the structural attributes of complicated road networks quantitatively, to compare different network structures, and to explore the structural evolution of networks in the spatial and temporal context. These measures can find application in urban planning and transportation practice.  相似文献   

9.
In the study of economic‐geographic structures, the shifting focus from the national state to the city and its region has highlighted the lack of reliable interurban data sets. The abundance of usable data sets on international structures and flows has no counterpart when studying interurban relations, which makes it hard to draw any extensive conclusions regarding the structure of world city networks. Instead of relying on available data sets, Peter Taylor has developed a method for generating data sets that, it is argued, can be used in research on the structure of the world city network. In this approach, actors are defined as cities with internal attribute service values, values reflecting the presence of different transnational service‐producing corporations in each city. The structural values between each pair of cities are then established by a mathematical formula based on the service value of each firm in each pair of cities. This procedure can be criticized on two accounts. First, although internal attributes on exceptional occasions can be used as a proxy and as a rough estimate for structural values, such studies must have a firm theoretical underpinning in order to be valid from a network‐analytical perspective. If not, such generated structural values become nothing more than a function of internal attributes, thus losing the whole basic idea of social network analysis. Second, the Taylor function used for generating structural values can be questioned. Why should a large presence of TNC offices in a pair of cities imply a larger city interlock link than would be the case between a high‐ranked city and a low‐ranked city, as the city with the larger service value probably serves cities with a lower service value with economic command, control, and support functions?  相似文献   

10.
徐珊  甄峰 《人文地理》2021,36(1):135-144
城市网络中心性是衡量城市地位、分析城市体系的重要概念.本文在剖析中心性理论内涵的演化后,提出网络中心性应当同时体现规模等级和要素流动的水平.通过区分静态网络和联系网络,论文构建了基于规模数据和流动数据的网络中心性评价体系,并以江苏、广东为例进行实证分析.研究发现:①从规模和联系两类城市网络中心性的视角识别首位城市是有效...  相似文献   

11.
Structural characteristics of social networks have been recognized as important factors of effective natural resource governance. However, network analyses of natural resource governance most often remain static, even though governance is an inherently dynamic process. In this article, we investigate the evolution of a social network of organizational actors involved in the governance of natural resources in a regional nature park project in Switzerland. We ask how the maturation of a governance network affects bonding social capital and centralization in the network. Applying separable temporal exponential random graph modeling (STERGM), we test two hypotheses based on the risk hypothesis by Berardo and Scholz (2010) in a longitudinal setting. Results show that network dynamics clearly follow the expected trend toward generating bonding social capital but do not imply a shift toward less hierarchical and more decentralized structures over time. We investigate how these structural processes may contribute to network effectiveness over time.  相似文献   

12.
Pattern Analysis Based on Type, Orientation, Size, and Shape   总被引:1,自引:0,他引:1  
Quantifying the pattern of geographically defined areas has proven useful in analyzing and understanding geographic processes. Pattern analyses most commonly used by geographers measure the spatial distribution of nonspatial variables at each point or in each area. The objective of this research is to develop and assess a pattern analysis for area-class maps that considers more than the nonspatial attributes when describing a spatial pattern. We examine whether similar geographic areas—similar with respect to attribute type and several geometric properties—exhibit particular spatial patterns (e.g., clustered, random, or dispersed). The additional attributes we include are orientation, size, and shape. We refer to the method as TOSS, reflecting the T ype, O rientation, S ize, and S hape of areas. The goal of considering these additional attributes is to capture the geometric aspects of pattern that other approaches to pattern analysis do not. Sets or groups of similar areas are created using cluster analysis, based on a variable standardization score using the Gower coefficient of similarity. The spatial distributions for each set of geographic objects are then calculated using nearest neighbor analysis. To test the effectiveness of the TOSS method, results from pattern analysis and the TOSS method are qualitatively and quantitatively compared. The TOSS method offers a novel approach to pattern analysis.  相似文献   

13.
The delegation of decision‐making capacity from one actor to another—known variously as authority or control—is a central phenomenon of organizational sociology. Despite its theoretical and practical significance, however, the dynamics of control within disrupted settings (such as disasters) remain poorly understood. Here, we shed light on this question by a reexamination of historical data on multiorganizational disaster response networks, using recently developed statistical methods for robust inference from error‐prone informant reports. Specifically, we test competing hypotheses about the relationship of control during the response process to the structure of interorganizational communication. We find that both the realized and normative response hierarchies are likely shaped by coordination among both nonadjacent alters and along indirect channels. Our results suggested that the communication structure of these networks is consistent with a control at a distance model of command. This article makes a substantial contribution to understanding the role of network structure in the emergence of control between organizations in disrupted settings. Additionally, our innovative approach to network inference will guide researchers in dealing with error‐prone data in their own research on policy networks.  相似文献   

14.
'Globalizing' regional development: a global production networks perspective   总被引:16,自引:0,他引:16  
Recent literature concerning regional development has placed significant emphasis on local institutional structures and their capacity to 'hold down' the global. Conversely, work on inter-firm networks – such as the global commodity chain approach – has highlighted the significance of the organizational structures of global firms' production systems and their relation to industrial upgrading. In this paper, drawing upon a global production networks perspective, we conceptualize the connections between 'globalizing' processes, as embodied in the production networks of transnational corporations, and regional development in specific territorial formations. We delimit the 'strategic coupling' of the global production networks of firms and regional economies which ultimately drives regional development through the processes of value creation, enhancement and capture. In doing so, we stress the multi-scalarity of the forces and processes underlying regional development, and thus do not privilege one particular geographical scale. By way of illustration, we introduce an example drawn from recent research into global production networks in East Asia and Europe. The example profiles the investments of car manufacturer BMW in Eastern Bavaria, Germany and Rayong, Thailand, and considers their implications for regional development.  相似文献   

15.
In recent years network analysis has been applied in archaeological research to examine the structure of archaeological relationships of whatever sort. However, these archaeological applications share a number of issues concerning 1) the role of archaeological data in networks; 2) the diversity of network structures, their consequences and their interpretation; 3) the critical use of quantitative tools; and 4) the influence of other disciplines, especially sociology. This article concerns a deconstruction of past archaeological methods for examining networks. Through a case study of Roman table wares in the eastern Mediterranean, the article highlights a number of issues with network analysis as a method for archaeology. It urges caution regarding the uncritical application of network analysis methods developed in other disciplines and applied to archaeology. However, it stresses the potential benefits of network analysis for the archaeological discipline and acknowledges the need for specifically archaeological network analysis, which should be based on relational thinking and can be expanded with an archaeological toolset for quantitative analysis.  相似文献   

16.
ABSTRACT Spatial econometrics has been criticized by some economists because some model specifications have been driven by data‐analytic considerations rather than having a firm foundation in economic theory. In particular, this applies to the so‐called W matrix, which is integral to the structure of endogenous and exogenous spatial lags, and to spatial error processes, and which are almost the sine qua non of spatial econometrics. Moreover, it has been suggested that the significance of a spatially lagged dependent variable involving W may be misleading, since it may be simply picking up the effects of omitted spatially dependent variables, incorrectly suggesting the existence of a spillover mechanism. In this paper, we review the theoretical and empirical rationale for network dependence and spatial externalities as embodied in spatially lagged variables, arguing that failing to acknowledge their presence at least leads to biased inference, can be a cause of inconsistent estimation, and leads to an incorrect understanding of true causal processes.  相似文献   

17.
京津冀交通路网结构特征及其演变的分形刻画   总被引:1,自引:0,他引:1  
龙玉清  陈彦光 《人文地理》2019,34(4):115-125
交通一体化是京津冀协同发展的基础和前提,合理的交通网络结构对提升城市群整体效能意义重大。本文基于1995-2030年多源交通路网数据,运用分形思想,研究京津冀以城市群为节点体系的交通路网空间结构特征及演化趋势。主要结论如下:①京津冀高等级路网仍有一定扩展潜力,交通网络整体等级结构尚不稳定,未达到一种优化的分形递阶状态。②各级路网空间分布具有自仿射特征,但各向异性扩展强度正在逐渐减弱,城镇化和交通一体化战略的实施正在促进各级路网逐渐向自相似的结构一体化方向演化。③交通路网空间结构演化与城镇用地结构不同步,可能与系统所处城镇化发展阶段有关。④高等级路网分维演化服从次数大于1的logistic模型,按照规划预期,各级路网空间发育将相继在2040年前后达到饱和;但按照规划设计高速公路建设将过度饱和,未来应及时调整规划。  相似文献   

18.
Spatial Cluster Detection in Spatial Flow Data   总被引:2,自引:0,他引:2       下载免费PDF全文
As a typical form of geographical phenomena, spatial flow events have been widely studied in contexts like migration, daily commuting, and information exchange through telecommunication. Studying the spatial pattern of flow data serves to reveal essential information about the underlying process generating the phenomena. Most methods of global clustering pattern detection and local clusters detection analysis are focused on single‐location spatial events or fail to preserve the integrity of spatial flow events. In this research we introduce a new spatial statistical approach of detecting clustering (clusters) of flow data that extends the classical local K‐function, while maintaining the integrity of flow data. Through the appropriate measurement of spatial proximity relationships between entire flows, the new method successfully upgrades the classical hot spot detection method to the stage of “hot flow” detection. Several specific aspects of the method are discussed to provide evidence of its robustness and expandability, such as the multiscale issue and relative importance control, using a real data set of vehicle theft and recovery location pairs in Charlotte, NC.  相似文献   

19.
This article develops a “polymorphic” approach to policy analysis, that is, an approach that draws on multiple forms of spatial reasoning. Specifically, the proposed framework deploys scale and network not merely as epistemological devices that make sense of “horizontal” and “vertical” politico‐institutional structures, but as co‐constitutive ontological processes that involve an ever‐shifting interplay among legacies, rhythms, and events. This polymorphic approach, we argue, facilitates the identification and the examination of the mobilization of social networks and of the attendant cross‐scalar interactions that must be articulated whenever a given policy is framed as a sensible and politically viable place‐based solution. The novel conceptual framework is then applied to the empirical investigation of the formulation of the complex moral, political, and economic environment that enabled the emergence of Ontario's controversial Ethanol in Gasoline Regulation. Our polymorphic approach reveals how this regulation is a (failed) attempt to reconcile Canada's legacy as a resource‐based economy and Ontario's legacy as a manufacturing‐based economy where value is added, with the need for more rational and less harmful resource extraction and for greener fuels that can sustain the current order. We build on the lessons drawn from this case study to suggest that our approach has wider applicability in that it can help create a process‐oriented, dynamic, and multi‐dimensional geography of policy‐making.  相似文献   

20.
旅游系统的空间分层拓扑结构研究   总被引:2,自引:0,他引:2  
旅游业的发展离不开旅游系统,因此掌握旅游系统要素的空间分布规律就十分必要。本文结合图论及计算机网络拓扑结构的知识,联系计算机网络中的分层理论,提出旅游系统要素分布的空间分层拓扑结构。通过对陕西省的旅游景点、交通线路、客源地的区域空间结构的分析,将旅游系统的空间拓扑结构分为客源地层和景点层两层。并利用旅游空间分层拓扑结构对陕西省的旅游景点、交通线路、客源地的空间分布规律进行了探讨,初步提出了分层空间旅游系统的计算分析方法。  相似文献   

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