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671.
Assessing representation error in point-based coverage modeling 总被引:2,自引:1,他引:2
Accurately representing geographic space in a digital environment continues to confound and challenge researchers. Carrying
out spatial analysis in a setting where geographic representation is subject to change poses problems to be addressed. In
this paper we examine spatial representation in the context of coverage-based location modeling. A geographic region can be
represented in a variety of ways. We present an evaluation of spatial representation in the location of facilities that provide
coverage oriented services. The analysis shows that the modeling results are sensitive to how spatial demand for service is
represented in a digital environment. We develop an approach for evaluating representational appropriateness. This research
contributes to spatial analysis integrated in geographic information system environment.
Received: 10 January 2001 / Accepted: 8 April 2002 相似文献
672.
Yoshiaki Ohsawa Hirofumi Kagaya Takeshi Koshizuka 《Journal of Geographical Systems》2002,4(3):325-342
When demand points are given as a planar map where projection method is explicitly stated, we usually know the latitudes
and longitudes of these points from the map. Then we can solve the Weber problem on the globe, and we do not suffer from errors.
This paper analyses how cylindrical projections cause distortion in the Weber problem when demands are distributed on the
Northern Hemisphere. First, we demonstrate that planar solutions are always located south of the spherical solution if the
Mercator projection, the equirectangular projections with standard parallels near the demands, or the equal-area projection
with the same characteristic is chosen. Second, we verify that this geographical tendency is inclined to hold when the demand
points, are distributed symmetrically, widely or toward the north.
Received: 15 August 2001 / Accepted: 20 April 2002
This paper was partially written while the first author was visiting the Department of Geography at the Catholic University
of Louvain, Louvain-la-Neuve, Belgium [1993–1994]. He is grateful for the hospitality of this department. An earlier version
of this paper was presented in 1994 at the Seventh Meeting of the European Operational Research Working Group on Locational
Analysis in Brussels, and in 1996 at the Fifth World Congress of the Regional Science Association International in Tokyo.
The authors would also like to thank the participants as well as three anonymous referees for their constructive comments. 相似文献
673.
674.
新建水源地如何最优布井,对水源地开采运行具有重大影响。本文介绍了0-1整数规划及其求解方法,并结合一个实际问题进行说明。作者应用0-1整数规划方法建立了北京密怀顺平原区拟建水源地最优布井的地下水管理模型,采用响应矩阵法将地下水模拟模型和管理模型相耦合,运用分支-定界法求出最优井位,并将优化井位与原拟定井位的计算结果进行了对比。结果表明,0-1整数规划能很好地解决最优布井问题,对水源地规划、基坑降水、地下水人工回灌等方面都具有一定的指导意义。 相似文献
675.
Yongmei Lu 《The Professional geographer》2003,55(4):422-433
Analyses of criminals' travel patterns can provide significant suggestions to improve crime management. This study extends the investigation of criminals' travel behavior from journey‐to‐crime to journey‐after‐crime. Moreover, new methods are developed to examine the spatial patterns of location pairs when restricted by the underlying geographical process. The methods are employed to investigate criminals' journey‐after‐auto‐theft in the city of Buffalo, New York. The analyses reveal that auto thieves' trips from vehicle‐theft locations to the corresponding vehicle‐recovery locations are local in nature. The travel distances are significantly shorter than the randomly simulated trips; the travel directions are biased from the random directions as well. 相似文献
676.
在线路施工的补充测量控制中,对先期控制点老坐标的如何使用,关系到新坐标的网形精度和与老坐标的差异程度.介绍了对先期控制点坐标进行赋权参加平差的方法,并给出评定结果的指标.用实例分析验证了这种方法的有效性. 相似文献
677.
The accurate location of the injection-induced microearthquakes in German Continental Deep Drilling Program 总被引:1,自引:0,他引:1
Introduction The scientific drilling belongs to the International Lithosphere Program and is one of the four lithospheres explorations. So far there are more than ten countries, which have taken the scientific drilling. The German Continental Deep Drilling Program was later than the others and is the sec-ond deep drilling, but is the most significant scientific super deep drilling in the world. The Ger-man Continental Deep Drilling Program (Kontinentales Tiefbohrprogram der Bundesrepub… 相似文献
678.
In recent years, Structural Health Monitoring (SHM) has emerged as a new research area in civil engineering. Most existing
health monitoring methodologies require direct measurement of input excitation for implementation. However, in many cases,
there is no easy way to measure these inputs - or alternatively to externally excite the structure. Therefore, SHM methods
based on ambient vibration have become important in civil engineering. In this paper, an approach is proposed based on the
Damage Location Vector (DLV) method to handle the ambient vibration case. Here, this flexibility-matrix-based damage localization
method is combined with a modal expansion technique to eliminate the need to measure the input excitation. As a by-product
of this approach, in addition to determining the location of the damage, an estimate of the damage extent also can be determined.
Finally, a numerical example analyzing a truss structure with limited sensors and noisy measurement is provided to verify
the efficacy of the proposed approach.
Sponsored by: Notional Science Foundation Grant CMS 99-00234 相似文献
679.
Benoît Flahaut Marie‐Alexandre Laurent Isabelle Thomas 《The Professional geographer》2002,54(1):67-82
This article demonstrates the operation of a simple optimal location‐allocation technique for solving the problem of locating one or several community recycling center(s) within a residential area. The article attempts to measure both transportation and externality costs in comparable units, and to incorporate them into the model. A sensitivity analysis of the results at the level of the nuisance provides further insight into the operation of the model and the relative importance of the quantification of pollution in applied location‐allocation problems. 相似文献
680.
黄河流域城市群产业高质量发展时空格局演变研究 总被引:3,自引:1,他引:2
以黄河流域城市群为研究空间单元,通过文献梳理识别流域产业高质量发展内涵,构建产业高质量发展评价指标体系,分析黄河流域城市群产业高质量发展的时空过程。研究结果显示:自2000年以来,黄河流域城市群产业高质量发展水平整体呈上升状态,并且由初始相对均衡转为东中西阶梯状递减的流域分异特征。产业各维度发展指数呈现不同的空间特征。产业活力、创新效率方面,上、中、下游分异明显;各城市群面临不同的产业结构性问题;上中游城市群产业空间联系不足,与中下游城市群差距在扩大;各城市群产业发展带来的生态环境压力趋于加重,黄河流域中游城市群成为环境污染的高值区。 相似文献