90年代世界贸易发展及空间格局变化的新特点

在世界贸易组织、日趋强烈的开放的区域主义倾向、跨国公司强劲的直接投资影响下，世界贸易正在经历着巨大变化，处在一个新的转换时期。本文从影响当今世界贸易发展的多重因素分析，揭示90年代世界贸易增长、内容结构以及空间格局发展变化的新特征，并展望世界贸易的未来发展。     

Race,Gender, and Spatial Segmentation in the Twin Cities*

This study analyzes commuting trends in a relatively vibrant setting during the 1980s to determine (a) how labor market segmentation correlates with differences in the spatial dimensions of local labor markets, and (b) whether this link represents a direct spatial effect, independent of earnings, travel mode, and part-time work. I use 1980 and 1990 PUMS data to analyze changes in racial and gender divisions in the workforce, and I develop an estimate of work trip distance to adjust for different travel modes. For all groups except white men, employment in a job “typical” of one's gender and racial group is associated with more localized commutes, but this effect is strongly mediated by variations in earnings and part-time work. Using a covariance structure model to control for these effects, I find no independent link between segmentation and longer commutes among African Americans. Earnings and commute distances remained unchanged over the decade for African Americans, providing no evidence of a purely spatial mismatch manifest in lengthening work trips without corresponding wage gains. The spatial dimensions of an employment mismatch for inner-city minorities are concealed through the replacement of production jobs by poorly paid service work in the expanding downtown economy of a vibrant regional center.     

Multifractal modeling and spatial statistics

In general, the multifractal model provides more information about measurements on spatial objects than a fractal model. It also results in mathematical equations for the covariance function and semivariogram in spatial statistics which are determined primarily by the second-order mass exponent. However, these equations can be approximated by power-law relations which are comparable directly to equations based on fractal modeling. The multifractal approach is used to describe the underlying spatial structure of De Wijs 's example of zinc values from a sphalerite-bearing quartz vein near Pulacayo, Bolivia. It is shown that these data are multifractal instead of fractal, and that the second-order mass exponent (=0.979±0.011 for the example) can be used in spatial statistical analysis.     

开发利用地理信息系统(GIS)综合分析地学信息进行矿产预测

众所周知,矿产资源预测是综合地学信息,进行优选靶区的有效手段之一。随着地学工作的深入和勘探技术的发展,已获取了大量的多源地学信息,如地质、地球物理、地球化学和遥感等资料。怎样从这众多的资料中提取有用信息进行综合分析,达到矿产资源预测的目的,一直是地学界探索的课题。过去,应用人工的方法来进行此项工作,不但费力、投资大,而且难以达到预期的效果,方法技术也不利于推广。如今,高速、高质量的计算机已趋于普及,使应用计算机技术高效地处理堆积如山的资料成为可能,尤其是近些年发展起来的地理信息系统(GIS),为综合处理地学资料的矿产资源预测的方法技术,开拓了广阔的前景。地理信息系统是一种计算机系统的应用软件,它集数据库管理和图像分析技术为一体,以空间数据迭加分析为重要特征。地学工作者进行矿产资源预测时,通常是从多源地学资料中提取有用信息,再应用专家知识,结合数学方法,如逻辑运算、贝叶斯(Bayes)规则等,建立预测模型,以模型的推理网格为线索,利用地理信息系统有效的空间分析手段,把各种证据图层综合迭加,最终产生以概率为指标的矿产资源预测图,高概率指示有利的矿产资源远景区,可作为勘探者和决策者进行勘查规划的依据。     

岩浆活动旋回与地球多层对流系统

从地球历史的节律角度讨论岩浆活动旋回。岩浆活动旋回可按时间与空间分出相互对应的不同尺度，进而可与深度尺度不同的地球多层对流系统相互对应，从而给予了岩浆活动旋回的动力学意义。岩浆活动的时间周期愈长，空间尺度亦愈大，需要的维持岩浆源存在的热能、挥发分供给的数量与深度亦愈大。     

A coherency function model of ground motion at base rock corresponding to strike-slip fault

IntroductionEarthquakedamagesurveyandresearchresultshavedemonstratedthatspatialdistributiondifferenceofgroundmotionisoneoftheimportantreasonswhichcausedlongstructure(eglongspanbridge,undergroundpipe)destroy.Thathowtoprovideareasonableinputofgroundmotionfieldforaseismicdesignoflongstructureisaurgentprobleminearthquakeengineeringfield.Atpresent,themethodtostudyspatialvariationofgroundmotionsisadoptingstatisticanalysisbasedondensearrayrecordssuchasSMART-1array,etc,togetcoherencyfunctionofground…     

Integrated spatial sampling modeling of geospatial data

Sampling is to, by efficient selection of samples, acquire the accurate information about the population (the research object) at less cost. Spatial sampling is a kind of sampling toward geospatial objects or features with spatial correlation. The differences between effi-cient sampling and completely universal survey lie in quality, time and cost. Sampling provides a kind of economical, prompt and accurate survey[13]. Efficient spatial sampling can be regarded as the optimization of the sampl…     

Variographic analysis of tropical forest cover from multi-scale remotely sensed imagery

Tropical forest mapping is one of the major environmental concerns at global and regional scales in which remote sensing techniques are firmly involved. This study examines the use of the variogram function to analyse forest cover fragmentation at different image scales. Two main aspects are considered here: (1) analysis of the spatial variability structure of the forest cover observed at three different scales using fine, medium and coarse spatial resolution images; and (2) the study of the relationship between rescaled images from the finest spatial resolution and those of the medium and coarse spatial resolutions. Both aspects are analysed using the variogram function as a basic tool to calculate and interpret the spatial variability of the forest cover. An example is presented for a Brazilian tropical forest zone using satellite images of different spatial resolutions acquired by Landsat TM (30 m), Resurs MSU (160 m) and ERS ATSR (1000 m). The results of this study contribute to establishing a suitable spatial resolution of remotely sensed data for tropical forest cover monitoring.     

基于灰色算子的尾矿坝浸润线混沌研究

对于尾矿坝浸润线时间序列，通过建立一个灰色算子，来弱化坝体高度、库内水位等因素所带来的确定性影响，突出混沌特性，形成新的时间序列，对该序列进行相空间重构后，求取关联维。德兴铜矿2#尾矿坝浸润线观测数据的分析结果表明，灰色算子能较好地处理混沌问题，浸润线时间序列存在着非整数维，是一个混沌系统：对于尾矿坝安全不能进行长期预测，而需要长期监测。     

天目湖热力学状况的监测与分析

根据2001年6月～2002年5月在天目湖进行的每月一次的全湖水温观测以及2002年5月25～26日在1号点的定点24h连续水温观测资料,分析研究了天目湖水温时空分布、垂直分布、温跃层的形成与变化以及湖泊热力学对溶解氧、营养盐的影响,揭示了各自的基本变化规律。结果表明:天目湖水温的日变化、年变化及垂直分布明显,而其水平差异不大;温跃层随着季节的变化而呈现增强-稳定-减弱-消失的周期变化;水温的变化以及温跃层的存在引起了水中溶解氧以及营养盐的变化。