Understanding Ethnic Residential Cluster Formation: new perspectives from South Australia’s migrant hostels

ABSTRACT

Throughout Australia’s history, successive governments have lamented the clustering of non-English-speaking migrants in ‘ethnic enclaves’ or ‘ghettos’. From the early Chinatowns of the 1800s till today, urban concentrations of ethnic groups have raised concerns and fears in local populations and authorities alike, despite decades of international research which suggests that ethnic residential clusters actually aid long-term assimilation and adjustment. Many of the ethnic residential clusters in contemporary Australia have been claimed to be a direct consequence of the migrant hostels and reception centres which operated between 1948 and the 1990s. This paper traces migrant settlement patterns in South Australia in rich detail, revealing the complexities of lived experiences that shape migrant settlement decisions. Against the background of public and scholarly debates over ‘ethnic enclaves’, and drawing on quantitative and qualitative historical research on the lived experiences of former hostel migrants, it analyses how migrant hostels and reception centres contributed to the settlement experiences of diverse migrants. We conclude that migrant hostels were just one among various factors that led to the growth and maintenance of ethnic residential clusters.     

Two-stage permutation tests for determining homogeneity within a spatial cluster

The discovery of spatial clusters formed by proximal spatial units with similar non-spatial attribute values plays an important role in spatial data analysis. Although several spatial contiguity-constrained clustering methods are currently available, almost all of them discover clusters in a geographical dataset, even though the dataset has no natural clustering structure. Statistically evaluating the significance of the degree of homogeneity within a single spatial cluster is difficult. To overcome this limitation, this study develops a permutation test approach Specifically, the homogeneity of a spatial cluster is measured based on the local variance and cluster member permutation, and two-stage permutation tests are developed to determine the significance of the degree of homogeneity within each spatial cluster. The proposed permutation tests can be integrated into the existing spatial clustering algorithms to detect homogeneous spatial clusters. The proposed tests are compared with four existing tests (i.e., Park’s test, the contiguity-constrained nonparametric analysis of variance (COCOPAN) method, spatial scan statistic, and q-statistic) using two simulated and two meteorological datasets. The comparison shows that the proposed two-stage permutation tests are more effective to identify homogeneous spatial clusters and to determine homogeneous clustering structures in practical applications.     

基于居民日常出行的生活空间单元的划分

本研究从行为地理学的视角,以空间稳定性假设为出发点,提出辨识生活空间单元的新方法。借鉴行为地理学关于微观个体的数据采集方法,在北京市清河永泰居住区随机选择了100 位居民为对象,对其日常活动空间的驻点信息进行了调查。通过对居住地和驻点联系的K-Means 空间聚类分析,对生活空间单元的范围进行了划分。分析表明:①属于相同生活空间单元的居民日常出行范围和频率比较接近;②小区建成年代、规划设计、房价等空间环境因素,对生活空间单元的形成具有显著影响;③共用的商业设施和交通服务设施是影响生活空间划分的主要因素。利用这一方法得出的生活空间范围可应用到地区环境性能评价、城市空间管制等多个研究领域。     

Spatially-explicit sensitivity analysis of an agent-based model of land use change

The complexity of land use and land cover (LULC) change models is often attributed to spatial heterogeneity of the phenomena they try to emulate. The associated outcome uncertainty stems from a combination of model unknowns. Contrarily to the widely shared consensus on the importance of evaluating outcome uncertainty, little attention has been given to the role a well-structured spatially explicit sensitivity analysis (SSA) of LULC models can play in corroborating model results. In this article, I propose a methodology for SSA that employs sensitivity indices (SIs), which decompose outcome uncertainty and allocate it to various combinations of inputs. Using an agent-based model of residential development, I explore the utility of the methodology in explaining the uncertainty of simulated land use change. Model sensitivity is analyzed using two approaches. The first is spatially inexplicit in that it applies SI to scalar outputs, where outcome land use maps are lumped into spatial statistics. The second approach, which is spatially explicit, employs the maps directly in SI calculations. It generates sensitivity maps that allow for identifying regions of factor influence, that is, areas where a particular input contributes most to the clusters of residential development uncertainty. I demonstrate that these two approaches are complementary, but at the same time can lead to different decisions regarding input factor prioritization.     

And Did the Walls Come Tumbling Down? Ethnic Residential Segregation in Four U.S. Metropolitan Areas 1980-2000

The initial releases of data from the 2000 U.S. Census allow exploration of the extent of change, if any, in residential segregation in four major cities, where substantial population growth has continued to generate increased ethnic diversity. Using a recently established method of classifying residential areas according to their ethnic composition which facilitates comparative study over time and space, this paper examines segregation trends in Chicago, Los Angeles, New York, and Miami over the period 1980-2000 in the context of recent discussions of the nature of residential patterns there. It finds that though there has been some reduction in the extent of extreme segregation areas that are predominantly either White or African American with consequent greater ethnic mixing at the census tract level, nevertheless cores of extreme segregation remain, and these are being extended with greater segregation of the Hispanic population. Ethnic residential segregation in United States' metropolitan areas attracted much research throughout the 20th century, with each census providing new impetus for mapping and analysis. The 2000 census will be no exception, providing data with which the extent of change can be assessed after a further decade in which discrimination on the grounds of race and color was illegal. This paper provides an initial exploration for four metropolitan areas that have experienced substantial recent multi-ethnic in-migration. Using a method for classifying residential areas designed to facilitate comparative studies over space and time, it explores the extent of desegregation during the previous 20 years for each of the four main census ethnic groups.     

沈阳市部门企业地理集聚与城市结构

基于产业空间聚集分布情况探寻城市结构特征,是当前大都市区实证研究中的聚焦点所在,但由于方法论的限制而无法真正揭示产业地理集聚之间的内在关联性。基于已有研究基础,试图通过完善潜力模型、设置距离参数、结合主成分分析法实现对产业地理集聚测度方法论的完善与发展,并选取极具代表性大都市区核心城市——沈阳市为样本单元,以2008年的经济普查部门企业数据开展实证检验。结果表明：沈阳市部门企业之间除了交通运输、仓储和邮政中心产业属于地方化经济外,其余的均为企业关联;水利、环境和公共设施管理业产业依附于制造业呈临街抑或隔街集聚,而与公共管理和组织产业之间同街道集聚;支配主角之间,存在中心CBD主宰制造业的布局,而制造业又在很大程度上影响着交通运输、仓储和邮政中心的布局;企业地理集聚形成的城市结构依然是一个明显的“单中心圈层”结构,没有表现出“去中心化”抑或多极化或分散化演变趋势。研究成果与现实情况基本吻合,侧面说明该模式对揭示城市产业地理集聚模式以及由此形成的城市结构特征具有一定的解释力。     

Using moment invariants to analyze cluster shapes and hypothesize potential causes

Although there are many algorithms and statistical tests to detect clustering of geographical phenomena, such as disease cases, the follow-up task of analyzing the cluster to explain its existence and mitigate the cluster is generally left to the researcher. These cluster detection methods are useful only for part of the process of identifying, understanding, and mitigating disease clusters. This research develops and presents a computer program that uses the information about the shape of the cluster to evaluate the hypotheses about potential causes. To achieve this, the shapes of the clusters are represented by image moment invariant statistics developed in the field of computer vision, and these shape statistics are compared against a database of moment invariants of shapes representative of several geographical processes, such as diffusion along roads and wind diffusion. Experiments using simulated data of different types of disease transmission were carried out, and the ability of the program to accurately classify the different types of diffusion demonstrates the viability of this approach to automated cluster analysis.     

Mapping the multiple geographies of mixed-ethnicity couples in Australia

Mixed-ethnicity partnerships are becoming increasingly common in Australia and other countries of high immigration. Formal and de facto marriages involving partners from different ethnic backgrounds are key indicators of decreasing social distance between groups. Yet mixed-ethnicity couples have received scant attention from Australian geographers. We use customised data from the 2011 Australian census to analyse the nation-wide distribution of several types of mixed-ethnicity couples. We focus on couples comprised of an Anglo-European (ethnic majority) partner, and a partner from a ‘visible’ ethnic minority group. Our analyses explore the residential geographies of mixed-ethnicity couples vis-à-vis ‘co-ethnic couples’ (where partners share the same ethnicity). We find that mixed-ethnicity couples are more widely dispersed across Australian cities and regions than comparative co-ethnic couples. However, each type of mixed-ethnicity couple has its own unique residential pattern: there are multiple geographies of mixed-ethnicity couples in Australia. These distinctive patterns reflect the migration and settlement histories of the couples’ constituent ethnic groups, but also hold great potential to shift seemingly entrenched ethnic residential geographies in the present and future.     

A geographic perspective on intra-urban racial/ethnic diversity, segregation, and clustering in Knoxville, Tennessee: 1990-2000

Racial/ethnic diversity in the United States has increased significantly in recent decades, with minority groups now accounting for almost one-third of the total population. At the same time, growing diversity has spread into rural and non-metropolitan areas. Research suggests that changing diversity in the ‘New South’ has seen growth of non-Black communities. The question, however, is the degree to which increasing diversity equates with increasing intermixing or, alternatively, whether racial/ethnic clusters retain their prominence. This paper examines the geographic manifestations of growing racial/ethnic diversity within intra-urban context, using census-tracts as scale of analysis in the metropolitan statistical area (MSA) of Knoxville in Tennessee. The statistics used for analyzing intra-urban variations include Diversity Score, Theil Entropy Index, and Location Quotient. Tract and Block-group data for White, Black, American Indian, Asian, All Others and Hispanic are used for computing these indices. This paper concludes that diversity has increased during 1990-2000, and has dispersed into suburban counties. However, segregation and clustering for certain minority groups has also increased, in particular African-Americans still remain the most segregated and most clustered community confined to specific geographic locations. This research holds significance as local economic development patterns are very much guided by the geographic variability of human and social capital. Applied research can suggest avenues for growth and can help rebuild local communities. This paper will also contribute to literature focusing on methodological challenges in measuring diversity and its geographic manifestations.     

Reconstructing the historical spatial land use pattern for Jiangsu Province in mid-Qing Dynasty

This study is proposed to reconstruct a high-resolution spatial distribution of historical land use pattern with all land use types to overcome low-accuracy and/or the monotonic land use type in current historical land use reconstruction studies. The year of 1820 is set as the temporal section and the administrative area of Jiangsu Province is the study area. Land use types being reconstructed include farmland, residential land (including both urban land and rural residential land), water body, and other land (including forest land, grassland, and unused land). Data sources mainly refer to historical documents, historical geographic research outcomes, contemporary statistics, and natural environmental data. With great considerations over regional natural resources and social and economic conditions, a few theoretical assumptions have been proposed to facilitate the adjustment on prefecture farmland, urban land, and rural residential land. Upholding the idea that the contemporary land use pattern has been inherently in sequence with the historical land use pattern as well as the land use pattern shall be consistent to its accessibility, this study reconstructs the land use pattern in Jiangsu Province in 1820 with 100 m*100 m grids based on accessibility analysis and comprehensive evaluation. The outcome has been tested as valid by regionalization and correlation analysis. The resulted spatial distribution shows that back in 1820 in Jiangsu Province: (1) farmland, urban land, rural residential land, water body, and other land take about 48.49%, 4.46%, 0.16%, 15.03%, and 31.86% of the total land area respectively; (2) the land use pattern features high proportion of land in farming while low-proportion land in non-farming uses while population, topography, and the density of water body lead to great spatial variations; and (3) the reconstruction methodology has been tested as reasonable based on significant positive correlations between 1820 data and 1985 for both farmland and rural residential land at the prefecture level.     

基于旅游影响感知的丽江古城居民类型划分

快速的旅游发展对旅游地居民产生了一定的影响。利用实证研究和统计分析的方法，作者对世界遗产地丽江古城居民就旅游影响的感知与态度进行了实地调查，采用快速聚类法将旅游地居民被调查居民被分为一定程度的憎恨者、积极的支持者和谨慎的支持者三种类型。居民中年长者、本地出生者多为一定程度的憎恨者；与旅游联系少、对旅游业依赖小的居民多为一定程度的憎恨者和谨慎的支持者；而在职的、与旅游业联系紧密、依赖大的居民多为积极的支持者。     

Early Detection of Terrorism Outbreaks Using Prospective Space–Time Scan Statistics

Terrorism is a complex phenomenon with high uncertainty involving a myriad of dynamic known and unknown factors. It is and will remain a challenge to predict or detect terrorism outbreaks at an early stage. This research presents an alternative approach for modeling terrorism activity, one that monitors and detects space–time clusters of terrorist incidents using prospective space–time scan statistics. Such clusters provide indicators of potential outbreaks of terrorist incidents. To evaluate the effectiveness of the approach, we analyze the terrorist incidents in the Consortium for the Study of Terrorism and Responses to Terrorism's (START) Global Terrorism Database (GTD) from 1998 to 2004. Clusters of terrorist events are detected at each time stamp and life trajectories of these clusters are constructed based on their space–time relationship to each other. Through the life trajectories and trends of clusters, we demonstrate how space–time scan statistics detect terrorism outbreaks at an early stage.     

清代中期江苏省土地利用格局网格化重建（英文）

This study is proposed to reconstruct a high-resolution spatial distribution of historical land use pattern with all land use types to overcome low-accuracy and/or the monotonic land use type in current historical land use reconstruction studies. The year of 1820 is set as the temporal section and the administrative area of Jiangsu Province is the study area. Land use types being reconstructed include farmland, residential land(including both urban land and rural residential land), water body, and other land(including forest land, grassland, and unused land). Data sources mainly refer to historical documents, historical geographic research outcomes, contemporary statistics, and natural environmental data. With great considerations over regional natural resources and social and economic conditions, a few theoretical assumptions have been proposed to facilitate the adjustment on prefecture farmland, urban land, and rural residential land. Upholding the idea that the contemporary land use pattern has been inherently in sequence with the historical land use pattern as well as the land use pattern shall be consistent to its accessibility, this study reconstructs the land use pattern in Jiangsu Province in 1820 with 100 m*100 m grids based on accessibility analysis and comprehensive evaluation. The outcome has been tested as valid by regionalization and correlation analysis. The resulted spatial distribution shows that back in 1820 in Jiangsu Province:(1) farmland, urban land, rural residential land, water body, and other land take about 48.49%, 4.46%, 0.16%, 15.03%, and 31.86% of the total land area respectively;(2) the land use pattern features high proportion of land in farming while low-proportion land in non-farming uses while population, topography, and the density of water body lead to great spatial variations; and(3) the reconstruction methodology has been tested as reasonable based on significant positive correlations between 1820 data and 1985 for both farmland and rural residential land at the prefecture level.     

西南丘陵山地区农村居民点土地整理模式——以重庆渝北区为例

通过对样本区域农村居民点布局及土地利用特点的研究 ,从丘陵山地区的自然环境条件和社会经济发展水平的实际出发 ,提出两种土地整理模式 :一是农林综合开发整理模式 ,即居民点闲置土地的复垦利用与抛荒地利用结合 ,与山地区退耕还林等生态建设工程结合 ,进行退宅还林 ;二是新村建设整理模式 ,即由政府对新村统一规划 ,供给道路等基础设施 ,引导农民集中建房的“政府引导型”农村居民点整理模式 ,并对重庆市渝北区新春村的新村建设的运作和效益进行了实证分析。     

Assimilation,Cultural Pluralism,and Social Exclusion among Ethnocultural Groups in Vancouver

In this paper we use custom tabulations from the 1991 Census for Greater Vancouver to compare the settlement experience of "traditional" immigrants with ethnic origins in Europe vs. those from other parts of the world. In particular we analyze the extent to which assimilation or cultural pluralism best describe the experience of the two populations. Assimilation is measured according to the degree to which an ethnic group moves toward the characteristics of the native-born population, while cultural pluralism is assessed from profiles of residential concentration, employment segmentation, nonofficial language use in the home, and ethnic inmarriage. We also assess the extent to which assimilation or cultural pluralism is associated with social exclusion in terms of economic and educational achievement. In general we find that assimilation best describes the experience of both groupings, though it is much slower for non-European immigrants and ethnicities, where cultural pluralism survives appreciably beyond the first generation. Cultural pluralism is associated with economic marginality for both groups in their first decade in Canada, though more profoundly for non-European immigrants in terms of personal income. In contrast there is some evidence that for the European-origin native-born, some ethnic separation remains and is associated with economic privilege. In general with length of residence, the relationship between variables becomes more ordered, and education emerges as a structuring effect in shaping economic outcomes.     

Clustering of temporal event processes

A temporal point process is a sequence of points, each representing the occurrence time of an event. Each temporal point process is related to the behavior of an entity. As a result, clustering of temporal point processes can help differentiate between entities, thereby revealing patterns of behaviors. This study proposes a hierarchical cluster method for clustering temporal point processes based on the discrete Fréchet (DF) distance. The DF cluster method is divided into four steps: (1) constructing a DF similarity matrix between temporal point processes; (2) constructing a complete linkage hierarchical tree based on the DF similarity matrix; (3) clustering the point processes with a threshold determined by locating the local maxima on the curve of the pseudo-F statistic (an index which measures the separability between clusters and the compactness in clusters); and (4) identifying inner patterns for each cluster formed by a series of dense intervals, each of which contains at least one event of all processes of the cluster. The contributions of the article are: (1) the proposed DF cluster method can cluster temporal point processes into different groups and (2) more importantly, it can identify the inner pattern of each cluster. Two synthetic data sets were created to illustrate the DF distance between temporal point process clusters (the first data set) and validate the proposed DF cluster method (the second data set), respectively. An experiment and a comparison with a method based on dynamic time warping show that DF cluster successfully identifies the preconfigured patterns in the second synthetic data set. The cluster method was then applied to a population migration history data set for the Northern Plains of the United States, revealing some interesting population migration patterns.     

A trajectory clustering approach based on decision graph and data field for detecting hotspots

Spatial clustering can be used to discover hotspots in trajectory data. A trajectory clustering approach based on decision graph and data field is proposed as an effective method to select parameters for clustering, to determine the number of clusters, and to identify cluster centers. Synthetic data and real-world taxi trajectory data are utilized to demonstrate the effectiveness of the proposed approach. Results show that the proposed method can automatically determine the parameters for clustering as well as perform efficiently in trajectory clustering. Hotspots are identified and visualized during different times of a single day and at the same times on different days. The dynamic patterns of hotspots can be used to identify crowded areas and events, which are crucial for urban transportation planning and management.     

基于局部运动向量时空统计的极光事件检测

极光动态过程的分析与理解对极光发生机制研究具有重要意义。本文提出了一种基于动态过程的极光事件检测方法。首先利用多尺度流体光流的方法提取出极光的局部运动场信息,然后基于局部运动场时空统计特性表征极光视频序列,最后实现对特殊极光事件的检测。实验结果表明,本文方法能够高效、准确地检索到特殊极光事件,并且检测结果不依赖于目标事件的选择。这一成果为开展基于大量连续观测的极光视频对极光动态过程进行统计分析的研究奠定了基础。     

Multi-level method for discovery of regional co-location patterns

Regional co-location patterns represent subsets of feature types that are frequently located together in sub-regions in a study area. These sub-regions are unknown a priori, and instances of these co-location patterns are usually unevenly distributed across a study area. Regional co-location patterns remain challenging to discover. This study developed a multi-level method to identify regional co-location patterns in two steps. First, global co-location patterns were detected, and other non-prevalent co-location patterns were identified as candidates for regional co-location patterns. Second, an adaptive spatial clustering method was applied to detect the sub-regions where regional co-location patterns are prevalent. To improve computational efficiency, an overlap method was developed to deduce the sub-regions of (k + 1)-size co-location patterns from the sub-regions of k-size co-location patterns. Experiments based on both synthetic and ecological data sets showed that the proposed method is effective in the detection of regional co-location patterns.     

Earthquake nests

Summary. Making use of extensive observations of micro-earthquakes available in the Tokyo region, Usami & Watanabe constructed a simple but effective method of exhibiting those regions where small earthquakes have clustered during a 4.5 yr period. Such clusters are defined by contour surfaces, and for convenience are termed earthquake nests .
If we accept the assumption that the magnitude of an earthquake is directly related to the volume previously undergoing intensified strain, and if we regard the nests as measures of such volumes, we can make rough estimates of the magnitudes of potential earthquakes in different parts of the Tokyo region. This method of assigning seismicity can be one way of calculating local risk. Repeated investigations can also detect changes in the tress field.