Spatial and temporal trends in information technology outsourcing

Over the last two decades information technology (IT) outsourcing has grown dramatically, and has emerged as a strategic choice for firms searching for ways to control their costs and maintain a competitive edge. The mechanisms driving its growth are not fully understood though. In this research, we employ an approach that focuses on geographic, temporal, and industrial proximity in a mechanism that identifies the process underlying the diffusion of IT outsourcing across firms within the U.S from 2000 to 2010. We focus on the role that firm location plays in the diffusion process, and use space-time clustering techniques from the epidemiology literature to understand the diffusion process. We identify 38 space-time clusters based on IT outsourcing announcement data and the locations of firm headquarters among U.S.-based firms. When supplemented with additional information, such as type of services outsourced, the metropolitan area of the headquarters, and related industry information; the results offer insights into various types of diffusion processes that have been identified in the literature but have not been documented to date in the empirical manner that we have been able to do.     

Explaining the settlement patterns of foreigners in Spain

This paper investigates the settlement patterns of the foreign population across the Spanish provinces over the period 2000–2009 and identifies the key determinants of these patterns. To this end, the paper determines the spatial distribution of foreign residents and, based on it, incorporates explanatory variables into a model designed to understand settlement patterns. After addressing the issue of spatial dependence, the model is estimated at both the aggregate level and for major areas of origin. The results reveal that social networks and economic factors, such as unemployment and per capita income in the hosting provinces, play a key role in explaining foreigners' settlement patterns in Spain. Significant differences exist, however, when areas of origin are allowed for.     

新疆气候时空变化特征及其趋势(英文)

Temperature and precipitation time series datasets from 1961 to 2005 at 65 meteorological stations were used to reveal the spatial and temporal trends of climate change in Xinjiang, China. Annual and seasonal mean air temperature and total precipitation were analyzed using Mann-Kendall (MK) test, inverse distance weighted (IDW) interpolation, and R/S methods. The results indicate that: (1) both temperature and precipitation increased in the past 45 years, but the increase in temperature is more obvious than that of precipitation; (2) for temperature increase, the higher the latitude and the higher the elevation the faster the increase, though the latitude has greater influence on the increase. Northern Xinjiang shows a faster warming than southern Xinjiang, especially in summer; (3) increase of precipitation occurs mainly in winter in northern Xinjiang and in summer in southern Xinjiang. Ili, which has the most precipitation in Xinjiang, shows a weak increase of precipitation; (4) although both temperature and precipitation increased in general, the increase is different inside Xinjiang; (5) Hurst index (H) analysis indicates that climate change will continue the current trends.     

Changes to urban form and commuting patterns: trends in two Danish city regions

This paper compares indicators of polycentricity in a monocentric (MUR) and a polycentric urban region (PUR) in Denmark at two points in time (1982 and 2002). It describes how population, jobs and commuting indicators of polycentricity develop and interact over time. Both the MUR and the PUR tend towards more balanced development. The increasing size of the main node in the PUR is the only deviation from the general trend. The general tendency towards a more polycentric regional structure was most marked in changing interaction and commuting patterns. Inter-urban commuting increased, while intra-urban commuting decreased, leading to dispersion of commuters and a rapid increase in commuting across the region. Commuting distances were shortest in the polycentric region, but it also had the highest growth rates. In both regions, the balancing trend leads to a dispersal of commuting demand over an increasingly complex web of origins and destination nodes. This tendency compels us to question whether people’s choice of residence is becoming increasingly irrelevant to their place of work. In relation to polycentricity and sustainability, this calls into question the degree to which proximity can be a valuable ‘asset’ in terms of planning sustainable transport outcomes connecting residence, jobs and service.     

Economic region net migration patterns in the USSR: 1979-89

"This article investigates economic region net migration patterns in the USSR during the 1979-89 intercensal period. Net in-migration and net migration rate increases (compared to 1970-79) occurred in both the western and eastern portions of the Northern USSR region, while net out-migration and rate declines occurred throughout the Southern USSR. Net in-migration again occurred to Siberia, especially Tyumen' Oblast, and there was a reduced rate of net out-migration from the Nonchernozem Zone and Central Chernozem Region of European RSFSR."     

Population migration across the Qinghai-Tibet Plateau: Spatiotemporal patterns and driving factors

Developing a comprehensive understanding of inter-city interactions is crucial for regional planning.We therefore examined spatiotemporal patterns of population migration across the Qinghai-Tibet Plateau(QTP)using migration big data from Tencent for the period between 2015 and 2019.We initially used decomposition and breakpoint detection methods to examine time-series migration data and to identify the two seasons with the strongest and weakest population migration levels,between June 18th and August 18th and between Oc-tober 8th and February 15th,respectively.Population migration within the former period was 2.03 times that seen in the latter.We then used a variety of network analysis methods to examine population flow directions as well as the importance of each individual city in migra-tion.The two capital cities on the QTP,Lhasa and Xining,form centers for population migra-tion and are also transfer hubs through which migrants from other cities off the plateau enter and leave this region.Data show that these two cities contribute more than 35％of total population migration.The majority of migrants tend to move within the province,particularly during the weakest migration season.We also utilized interactive relationship force and ra-diation models to examine the interaction strength and the radiating energy of each individual city.Results show that Lhasa and Xining exhibit the strongest interactions with other cities and have the largest radiating energies.Indeed,the radiating energy of the QTP cities cor-relates with their gross domestic product(GDP)(Pearson correlation coefficient:0.754 in the weakest migration season,WMS versus 0.737 in the strongest migration season,SMS),while changes in radiating energy correlate with the tourism-related revenue(Pearson correlation coefficient:0.685).These outcomes suggest that level of economic development and level of tourism are the two most important factors driving the QTP population migration.The results of this analysis provide critical clarification guidance regarding huge QTP development dif-ferences.     

Spatial and temporal patterns of fires in tropical savannas of Indonesia

This paper examines spatial and temporal patterns of large to medium‐sized fires across the Indonesian Archipelago using remote sensing, particularly the MODIS fire products, over a 14 years period (2000–13 inclusive) in conjunction with climatic and land data in a GIS. Results showed fires (burned area and number of fires) were detected the most in year 2002 and least in 2010. The extent of burning was correlated with the annual Southern Oscillation Index with most burning occurring during times of sustained negative SOI values, which generally means drier conditions across the region. Most of the detected fires occurred in the middle of the dry season and in drier eastern Indonesia. Across Indonesia, approximately 1.5 per cent of available open vegetation area burned, whereas only 0.5 per cent of forest area burned. Most open vegetation burning was detected in the savanna with an area equivalent to 11.1 per cent of its extent being burned over the 14 years. On Sumba Island, where the pronounced dry season extends for at least four months, open vegetation is the most common land cover type, of which 99 per cent burned by area over the study period making it the island with the most burned areas in the Indonesian Archipelago.     

On the move: explaining migration patterns in Estonia during the transition period

This paper attempts to explore the migration patterns during the transition period in Estonia. A structuration approach was used to analyze data from the Estonian Statistical Office collected in 1997. Findings show that for migration between urban and rural areas, work-related reasons have been the most important motivating factor in urban growth during the transition period. Also considered are the family and education. In relation to sociodemographic structure of the population, men cite work, while women count family-related reasons, as the main motive for migrating. As to nonregistration, the most significant reason relates to issues of ownership. Because migrants are living in rented housing, it is not possible for them to register even if they desire to do so. Other reasons include "temporary", associated with study and work; "juridical", bureaucratic matters; and "multiple places of residence". This analysis, however, is incomplete because the attitudes and patterns of behavior have only partially or perfunctorily been related to the dramatic changes that have occurred in Estonian society. Proper statistical data are needed to help examine trends at a more disaggregated spatial level.     

Union republic migration trends in the USSR during the 1980s

"This article examines union republic migration trends in the USSR between 1979 and 1987 and prospects for indigenous out-migration from rural areas in Central Asia. The study is based on migration data derived by the residual technique and migration data from the 1985 microcensus. Results indicate that a south-to-north and probably Russian-dominated migration trend emerged in the 1980s, one which marks an almost complete reversal from earlier periods, especially 1959-70. Although Central Asia continues to have low levels of indigenous out-migration, labor surpluses and relatively waning capital investment in Central Asia may change this situation."     

中国陆地生态系统净初级生产力时空特征模拟

In this paper,we use CEVSA,a process-based model,which has been validated on regional and global scales,to explore the temporal and spatial patterns of Net Primary Productivity (NPP) and its responses to interannual Climate fluctuations in China‘‘‘‘‘‘‘‘s terrestrial ecosystems over the period 1981-1998,The estimated results suggest that ,in this study period,the averaged annual total NPP is about 3.09 Gt C/yr^-1 and average NPP is about 342 g C/m^2,The results also showed that the precipitaion was the key factor determining the spsatial distribution and temporal trends of NPP. Temporally,the total NPP exhibited a slowly increasing trend.In some ENSO years( e.g.1982,1986,1997)NPP decreased clearly compared to the previous year,but the relationship between ENSO and NPP is decreased clearly compared to the previous year,but the relationship between ENSO and NPP is complex due to the integrated effects of monsoons and regional differentiation. Spatially,the relatively high NPP occurred at the middle high latitudes,the low latitudes and the lower appeared at the middle latitudes,On national scale,precipitaion is the key conntro factor on NPP variations and there exists a weak correlation between NP and temperature ,but regional responses are greatly different.     

中国山地垂直带信息图谱的探讨

通过构建山地垂直带谱数据结构,实现了垂直带谱数字化,增强了垂直带谱的可视化;提出了垂直带谱的三级体系：以基带区分一级带谱,以特征垂直带区分二级带谱,以垂直带组合结构、优势垂直带及垂直高度及宽度区分三级带谱;概括出山地垂直带谱的7种变化模式：同构模式、结构递减模式、突变模式、纬向递减模式、经向减升模式、阶梯递增模式和高原叠加模式;归纳出垂直带谱的5种生态类型：与自然地带相联系的顶极带谱、与主要山地相联系的基本带谱、与特殊地生态现象相联系的过渡／特殊带谱、与人类干扰相联系的扰动带谱,以及与强烈人类活动相联系的次生带谱。深入比较和分析垂直带信息图谱,可以揭示更多的地学信息。     

Urban transformations,migration and residential mobility patterns in African secondary cities

Abstract

Urban growth is a significant trend in Africa. Scholarly attention and urban planning efforts have focused disproportionately on the challenges of big cities, while small and medium-sized urban settlements are growing most rapidly and house the majority of urban residents. Small towns have received some attention, but very few studies have focused on secondary cities. This paper offers a study of urban transformations, migration and residential mobility patterns in Arusha, a rapidly growing secondary city of Tanzania. Arusha functions as a major attraction for migrants and in-migration is a central dynamic shaping transformation processes in central areas characterized by high population turnovers, vibrant rental markets and widespread landlordism. There is also a considerable degree of intra-urban residential mobility within and between central areas. Intra-urban residential mobility is the most important dynamic shaping transformation processes in peripheral areas characterized by long-term urban residents moving from central parts of the city as part of a process of establishing themselves as homeowners. Overall, the paper provides crucial insights on how migration and residential mobility patterns influence processes of urban growth and transformation in the context of large secondary city, and thereby contributes to fill a significant knowledge gap on secondary cities in Africa.     

A proportional odds model of human mobility and migration patterns

The modelling of human mobility and migration patterns has received much attention due to its substantial importance. Despite long-term efforts, we still lack a modelling framework that captures mobility patterns and further obtains a prospective view of movement trends with regards to diverse impacting factors. Here, we propose a proportional odds model of human mobility and migration (POM-HM) that takes a probabilistic approach to model human movements. Our model is based on the migration probability with a log-logistic distribution under the proportional odds assumption. Explanatory variables are introduced into the model by re-parameterizing the probability distribution function. The two resultant functions, namely, the migration strength and cumulative hazard, are used to estimate regional differences among travel fluxes and their tendencies. The performance of the POM-HM in terms of its validity and accuracy is examined and compared with the gravity model and the radiation model. The probability-based modelling framework enables us to investigate regional variations in migrant fluxes consequently further predict potential future patterns. In short, our modelling approach captures the probabilistic nature of human mobility and migration and furthers our understanding of both the spatiotemporal patterns of population movements and the impacts of various driving forces.     

Time-space analysis of internal migration in Spain (1962-1993): with special attention to the changes in migration pattern in the 1970s

"In this study, the internal migration in Spain from 1962 to 1993 is analyzed from the viewpoint of migration flows, with special emphasis on the spatial scale and direction of migration as well as the migration fields.... The evolution of the spatial scale and direction of migration shows a radical change in the middle 1970s: migrations from 1962 to 1975 (first period) were unidirectional movements at great distance (interprovincial and interregional), whereas those from 1976 to 1993 (second period) are characterized by the weight of intraprovincial movements and the bidirectionality of interprovincial movements. Through the two periods, the major sector in which migrants are employed has shifted from the industry to the service sector." (EXCERPT)     

2000—2020年中国省际人口迁移格局的演化特征及影响因素

准确认识和把握21世纪前20年中国人口迁移的地理格局和影响因素,是推动新型城镇化建设及区域均衡发展的关键科学问题。借助特征向量空间滤波泊松伪最大似然估计（ESF PPML）引力模型,基于第六次和第七次全国人口普查数据、2005年和2015年全国1%人口抽样调查数据,研究了2000—2020年中国省际人口迁移的时空演化特征及影响因素。主要结论为：① 2000—2020年间人口迁移格局总体稳定,具有较强的不平衡性和网络溢出效应,大量人口从中部、西部、东北地区迁移至东部地区;② 人口迁移格局稳中有变,不平衡程度和空间集聚程度逐渐减弱,人口迁移和人口分布显现出南北分异趋势,东北地区人口迁出强度不断增强; ③ 传统引力模型因素（人口规模、地理距离）、地区社会经济发展因素（工资差异、科技教育投入占比、医疗水平）、社会网络因素、环境舒适度（PM_2.5浓度）以及生活成本（住宅价格占比）共同影响人口迁移格局;④ 区域经济差异对省际人口迁移的影响作用逐步弱化,人口迁移逐渐转变为对工资收入、高质量公共服务、环境舒适度等多因素考虑的决策过程,生活成本逐渐对人口迁移产生显著影响。     

A method for discovery and analysis of temporal patterns in complex event data

Pattern analysis techniques currently common within geography tend to focus either on characterizing patterns of spatial and/or temporal recurrence of a single event type (e.g., incidence of flu cases) or on comparing sequences of a limited number of event types where relationships between events are already represented in the data (e.g., movement patterns). The availability of large amounts of multivariate spatiotemporal data, however, requires new methods for pattern analysis. Here, we present a technique for finding associations among many different event types where the associations among these varying event types are not explicitly represented in the data or known in advance. This pattern discovery method, known as T-pattern analysis, was first developed within the field of psychology for the purpose of finding patterns in personal interactions. We have adapted and extended the T-pattern method to take the unique characteristics of geographic data into account and implemented it within a geovisualization toolkit for an integrated computational-geovisual environment we call STempo. To demonstrate how T-pattern analysis can be employed in geographic research for discovering patterns in complex spatiotemporal data, we describe a case study featuring events from news reports about Yemen during the Arab Spring of 2011–2012. Using supplementary data from the Global Database of Events, Language, and Tone, we briefly summarize and reference a separate validation study, then evaluate the scalability of the T-pattern approach. We conclude with ideas for further extensions of the T-pattern technique to increase its utility for spatiotemporal analysis.     

Spatial and temporal patterns of solar radiation in China from 1957 to 2016

Solar energy is clean and renewable energy that plays an important role in mitigating impacts of environmental problems and climate change. Solar radiation received on the earth’s surface determines the efficiency of power generation and the location and layout of photovoltaic arrays. In this paper, the average daily solar radiation of 77 stations in China from 1957 to 2016 was analyzed in terms of spatial and temporal characteristics. The results indicate that Xinjiang, the Qinghai-Tibet Platea...     

Longer distance commuting as a substitute for migration in Britain: a review of trends,issues and implications

"Drawing on analyses of commuting data from secondary sources as well as on selected results from a research project on long-distance commuting in Britain, this article investigates the extent to which, and why, households may choose to substitute longer distance commuting for migration. Reasons for long-distance weekly commuting, and associated advantages and disadvantages from individual, household and employer perspectives, are outlined. The evidence points to increasing complexity in home and working lives, with important implications for housing, transport and human resource management policies, as well as for family life."     

中国东部地区流动人口城市间横向迁移规律

基于中国东部地区6 个城市流动人口问卷调查,并在对已有人口迁移规律研究进行梳理的基础上,通过比较流动人口每一次迁移前一城市和后一城市的差异以及整个迁移过程中迁移速度、迁移距离、迁移城市规模、城市经济发展水平、区域路径等方面的变化趋势,分析流动人口进入城市后在城市间横向迁移的规律和特点。研究发现:东部地区流动人口城市间横向迁移不仅速度快,城市平均居留时间短,而且在多次迁移过程中迁移流向、迁移的空间轨迹方面呈现出更为复杂的特点:随着迁移次数的增加,迁移距离增加,遵循由近及远的同时回流现象明显;随着迁移次数的增加,由收入较高城市流向收入较低城市的比例以及流向中等城市的比例显著提高,不存在由大到小的递补特征;在相邻城市或相同经济区范围内多次往返迁移现象明显。     

中国省域科技创新模式及其时空演变

中国的经济增长模式正在由要素驱动型向创新驱动型转变,适宜的科技创新模式是促进中国经济社会协调可持续发展的关键。基于熵值法构建综合指标评价体系,运用Theil指数对中国科技创新投入与产出水平的时空演变进行分析,并结合K-means聚类分析法将其分别归为相同的5个等级。根据不同的投入—产出组合,得出投入产出协调型、投入领先型与产出领先型3个科技创新类型及其子类。最后,利用多阶段DEA模型,从科技创新投入的角度,将科技创新模式划分为混合驱动型、创新平台驱动型、人力与资本驱动型和人力驱动型四类;从科技创新产出的角度,划分为经济创新导向型、知识与经济创新导向型和知识创新导向型三类模式。对比发现,中国科技创新模式与科技创新类型的时空演变呈现高度的相关性。在此基础上,为中国未来区域科技创新的发展提出若干建议。