基于延迟自相关特性的码速率测量技术

通信信号的识别与解调是通信侦察的重要研究内容，在通常情况下，通信信号的很多参数并不知道。本文介绍了一种基于通信信号码延迟自相关特性的码速率测量技术，并给出了码速率测量理论分析及基于硬件的实现技术，仿真和实验结果表明本方案具有较高的测量性能。     

探索性空间数据分析模型研究

探索性空间数据分析是空间经济计量学的一个重要领域。解释与空间位置相关的空间依赖、空间关联或空间自相关现象。目前在国内外的应用也越来越广泛。本文就探索性空间数据分析模型进行了综合介绍，并分析了其在未来的应用前景。     

Asymptotic confidence bands for the estimated autocovariance and autocorrelation functions of vector autoregressive models

This paper provides closed-form formulae for computing the asymptotic covariance matrices of the estimated autocovariance and autocorrelation functions of stable VAR models by means of the delta method. These covariance matrices can be used to construct asymptotic confidence bands for the estimated autocovariance and autocorrelation functions to assess the underlying estimation uncertainty. The usefulness of the formulae for empirical work is illustrated by an application to inflation and output gap data for the U.S. economy indicating the existence of a significant short-run Phillips-curve tradeoff.First version received: November 2002/Final version received: September 2003     

Identifying the internal structure evolution of urban built-up land sprawl (UBLS) from a composite structure perspective: A case study of the Beijing metropolitan area,China

Differences in the internal composite structure during urban built-up land sprawl (UBLS) will generate different effects, and thus, a city’s spatial structure has important bearings on urban sustainability. This study investigates the spatial and temporal characteristics of the internal structure and allocation relationship of UBLS using multivariate spatial correlation and the Weaver-Tomas composite coefficient based on site data of granted built-up land parcels. Moreover, the composite structure evolution process of UBLS and its driving mechanism are examined in this study. The results reveal that the amount structure of the three types of UBLS (i.e. industrial land sprawl, residential land sprawl and commercial land sprawl) tended to be balanced during the study period. Following the transformation and upgrade of the urban industry structure, the overall composite structure of UBLS ranged from single residential land-use structure (Res.) to industrial-residential land-use structure (Ind.-Res.) In the early period of land marketization, the marketization land granting mechanism caused low spatial correlation between the various types of UBLS and a single composite structure, i.e. Res., single commercial land-use structure (Com.), and residential-commercial land-use structure (Res.-Com.). Subsequently, a dual-driving force including the market economy and government interventions caused a relatively high degree of spatial correlation and a multiple composite structure, i.e. Ind.-Res. and industrial-residential-commercial land-use structure (Ind.-Res.-Com.). However, the evolution characteristics of the composite structure in various regions illustrate some problems, such as the spatial isomorphism phenomenon of the composite structure and the dislocation of urban built-up land allocation. The urban internal built-up land spatial layout pattern is the embodiment of two dominant driving forces, the market and the government, interacting with each other according to natural and socioeconomic conditions. Therefore, we suggest that it is necessary to reform the future urban built-up land granting mechanism based on market guidance, and the composite structure of UBLS should be adjusted according to the regional function. The government should reinforce the macro-control of land-use planning for the dispersed granted land parcels so as to optimize the urban land-use structure.     

Closeness matters. Spatial autocorrelation and relationship between socioeconomic indices and distance to departmental Colombian capitals

Socioeconomic indices that developing economies use to combat poverty may show a limited picture of all the variables related to the problem. This study analyzes spatial autocorrelation and clusters of three socioeconomic indices—living conditions, multidimensional poverty, and unsatisfied basic needs—in Colombia to explore the relation of the identified clusters with their physical distance from departmental capitals. Using a local index of spatial autocorrelation, it evaluates spatial patterns and the clustering of socioeconomic indices. Correlation analysis tests the relation between clusters and their distance from departmental capitals in three departments. The spatial patterns of indices in Colombia correspond to the model of economic development in the country and reveal the regions where socioeconomic characteristics form clusters of desirable/undesirable conditions and departments where the distance from main cities may be seen as a condition for a higher quality of life.     

The influence of neighborhood environment and household travel interactions on school travel behavior: an exploration using geographically-weighted models

Professional and popular interest in active school transportation (walking and cycling) is matched by an emerging literature on this topic. This paper explores school travel behavior of 11-year old children in Toronto, Canada. In particular, the effects of the neighborhood environment and caregiver-child travel interactions on travel mode choice were studied. Results indicate that the built environment near both home and school locations was associated with the odds of walking. However, predicted built environment effects were less accurate in some neighborhoods. Availability of adults at the time of school travel likely encouraged driving. School transportation interventions that broadly consider school and neighborhood-oriented policies and enable independent mobility may increase walking rates. Presence of spatial autocorrelation in the prevalence of walking suggests that more research is required to understand inter-household similarities in behaviors that are spatially structured.     

1990年以来江苏省区域经济差异时空格局演化及其成因分析

以1990—2007年江苏省县域人均GDP为研究指标,运用不平衡指数和空间统计模型对江苏省区域经济发展水平进行定量研究,并结合GIS的空间分析功能,系统分析了江苏省区域经济发展时空差异及空间格局演化。结果表明:江苏省区域经济发展在空间上具有较强的自相关性,在整体格局上呈现出一定的集聚态势,空间格局更多表现为苏南部分地区的高度集聚和苏北部分地区的集聚态势,成为江苏省区域经济发展的集聚核心区和低度集聚区,而苏中地区的集聚态势显得并不强烈。同时,针对区域经济自相关性发展趋势进行解释并指出以县域经济为单元的区域经济发展空间差异将长期存在。最后,构建空间数据模型对此种格局形成的原因进行空间统计学上的探讨,指出规模企业空间分布差异及人才空间分布差异是导致县域经济发展差异的主要因素,为区域经济差异分析提供了一种交互式的、可视化的新手段,进而为政府部门制定区域经济协调发展政策提供决策依据。     

美国行政中心空间与规模特征及其成因研究

行政中心是行政区划的基本要素之一,行政中心尽量靠近地理中心对行政管理和促进区域发展平衡有积极的理论和现实意义。文章提出了行政中心与地理中心偏差的计算公式,运用空间统计分析方法结合Ar-cGIS软件,以美国为例,分析了美国县治与地理中心地理偏差的空间分布和数据特征以及州府与州最大城市的人口规模关系特征,总结了产生以上特征的自然、历史和政治上的原因,并运用空间可视化方法直观地显示分析结果。分析结果表明：①美国的县治普遍比较接近地理中心,其接近程度有由东部向西部递减的趋势且存在一定的空间集聚;②州府大多数并非州最大城市,人口较少。最后从行政中心区位选择和区域发展平衡两方面得出对中国的启示,为中国行政区划改革和区域经济发展提供借鉴。     

城市地价空间自相关分析——以宿州市为例

运用全局和局域自相关统计量及地统计学半变异函数分析方法,对宿州市商业和住宅地价的全局自相关、各项异性及局域自相关特征进行了全面分析.结果表明:在2 800m范围内,宿州市商业和住宅地价均存在较强的正自相关性且趋于高值集聚,随着相关距离的增大,地价半方差按球状模型曲线增长,自相关性逐渐减弱;在不同方向上,地价的空间自相关特征不尽相同,南北方向上的空间自相关范围要大于东西方向,但随机性较强,自相关程度较东西方向弱;在全局呈显著自相关的情形下局域地价也主要呈空间集聚格局,但部分地区表现出异质性.