CONCEPTUALIZING SMALL TOWNS AS URBAN PLACES: THE PROCESS OF DOWNTOWN REDEVELOPMENT IN GALENA,ILLINOIS

This research investigates the process through which small-town central business districts (CBDs) are transformed into visitor-oriented attractions. A case study of Galena, Illinois, reveals that the dominant characteristics of the downtown redevelopment process are applicable to metropolis and small town alike. Similar economic “tools,” enabling legislation, and other mechanisms are available to essentially all municipalities regardless of size. Further, growth coalitions and interest groups are formed to promote the particular use and exchange values of CBDs throughout the urban hierarchy. What differs between small town and large metropolis, however, is the way in which contemporary CBDs are perceived by the community. While the metropolitan downtown is now largely viewed as a “command center” within a global economy, the small-town CBD is still varyingly perceived as the community's economic and social center. Such contrasting conceptions of downtown hold implications for the ability to successfully transform Main Street into a tourist attraction without generating substantial inter-community conflict. [Key words: small town, historic district, main street, downtown redevelopment, tourism.]     

Urban Employment Subcenters and Sectoral Clustering in Montreal: Complementary Approaches to the Study of Urban Form

Since the late 1980's there has been renewed interest in the study of employment polynucleation within metropolitan areas, fed in part by the move to suburban locations of high-order service functions. In parallel, a growing body of research has underlined the role which proximity plays in information exchange, innovation and growth. So far there have been only limited attempts to merge these two approaches and investigate the degree to which local agglomeration economies and positive externalities may underpin the creation of suburban employment poles. In this paper a first step is taken in this direction by proposing an approach to systematically investigate the colocation of economic activities within a metropolitan context. It is found that the groups of economic activities which systematically tend to colocate closely mirror those activities which would be grouped together along sectoral lines.     

Postindustrial Manufacturing in a Sunbelt Metropolis: Where Are Factories Located in Phoenix?

Manufacturing establishments are integral to the spatial structure of fast-growing Sunbelt metropolitan areas, but most concepts and theories of intrametropolitan location were largely developed for an earlier technological era and different spatial contexts. This article investigates the location of nine disaggregated manufacturing sectors in Phoenix, Arizona, showing varying degrees of central core concentration and metropolitan-wide clustering. Distinct sectoral co-location patterns are also evident. We interpret our results as evidence that the intrametropolitan location of postindustrial manufacturing is best understood as a series of spatial distributions with varying concentration, centralization, clustering, and other order-based characteristics. There is little evidence that randomly scattered discrete industrial zones have developed nor that spatial patterns are uniform. Enduring lock-in effects tied to transportation infrastructure are pivotal to understanding the locational distribution of manufacturing industries in metropolitan Phoenix. Results do not support a hypothesis that a positive relationship exists between establishment size and distance from sectoral mean centers.     

一等水准点之记标准化与规范化研究

为保证一等水准点之记精度与质量,提高测绘人员野外工作效率,对目前的一等水准点之记进行了探讨与分析,指出了其详细位置图与点位,详细说明表达、标石断面图绘制和经纬度书写及交通路线描述中存在的缺点,并基于此提出了若干改进意见,这在一定程度上促进了一等水准点之记信息的标准化与规范化。     

Toward seamless indoor-outdoor applications: Developing stakeholder-oriented location-based services

Location-Based Services (LBS), an emerging new business based on smartphone and mobile networks, are becoming more and more popular. Most of these LBSs, however, only offer non-seamless indoor/outdoor applications and simple applications without giving stakeholders the chance to play an active role. Our specific aim is to solve these issues. This paper presents concepts to solve these issues by expanding the Open Location Services Interface Standard (OpenLS) to allow seamless indoor/outdoor positioning and to extend the content of the services to include information recommended by stakeholders.     

基于Harris兴趣值的影像线特征高精度提取方法

针对影像高精度线特征提取问题,本文提出一种基于Harris兴趣值的直线提取方法:利用EDISON算法提取影像的初始边缘,并将其细化到单像素,对提取的每一边缘点在其法线方向进行基于Harris兴趣值的子像素定位,并将精确定位后的点拟合成直线.通过采用两幅真实影像进行试验,证实了本文所提方法的有效性.     

Application of Backward Nonlinear Local Lyapunov Exponent Method to Assessing the Relative Impacts of Initial Condition and Model Errors on Local Backward Predictability

Initial condition and model errors both contribute to the loss of atmospheric predictability. However, it remains debatable which type of error has the larger impact on the prediction lead time of specific states. In this study, we perform a theoretical study to investigate the relative effects of initial condition and model errors on local prediction lead time of given states in the Lorenz model. Using the backward nonlinear local Lyapunov exponent method, the prediction lead time,also called local backward predictability limit(LBPL), of given states induced by the two types of errors can be quantitatively estimated. Results show that the structure of the Lorenz attractor leads to a layered distribution of LBPLs of states. On an individual circular orbit, the LBPLs are roughly the same, whereas they are different on different orbits. The spatial distributions of LBPLs show that the relative effects of initial condition and model errors on local backward predictability depend on the locations of given states on the dynamical trajectory and the error magnitudes. When the error magnitude is fixed, the differences between the LBPLs vary with the locations of given states. The larger differences are mainly located on the inner trajectories of regimes. When the error magnitudes are different, the dissimilarities in LBPLs are diverse for the same given state.     

沂南县贫水山区找水定井技术研究

综合分析沂南县气候、自然、地理,尤其是地质与水文地质条件,及2011年国土资源抗旱打井工作成果,结合沂南地下水含水岩组分布、赋存、地下水运移特征、构造对岩溶发育与地下水运动的控制等。得出沂南县岩溶地下水补给径流区的构造破碎带及其附近地下水相对富集。地下水富集特征可分为：构造带控水型、火成岩体阻挡富水型、断裂影响带强富水型及远离构造破碎带弱富水型等几种类型。根据岩溶地下水补给径流区地下水富集规律的分析研究,为今后贫水山区找水定井提供参考。     

双介质摄影测量共线理论研究

从摄影光学理论出发,推导摄影物镜成像系统的基点位置公式;利用针孔成像模型,分析得出摄影物镜的投影中心即为成像系统两节点的等效;简要阐述双介质摄影测量的传统观点,利用同一摄影物镜在不同介质中构成的光学系统,说明双介质摄影测量成像系统基点位置相对单介质时发生变化,并在此基础上提出与传统观点不同的看法——双介质摄影测量共线理...     

提高无控制点星载SAR影像的定位精度研究

针对无控制点情况下星载SAR地面目标高精度定位问题,提出在整个成像条带中任选一景SAR影像,并基于全球DEM数据生成模拟的SAR影像,然后通过自动或半自动匹配方式寻找一个控制点,修正整个条带的轨道参数,从而消除了系统误差的影响,提高了整个SAR条带影像的定位精度。