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21.
本文研究诸如钢铁、有色金属、基本化工等一类行业的空间配置。由于韦勃、廖施的理论的一些前提条件在这里不存在,使得他们的研究方法显得十分不足。本文作者建立了具有对偶的线性规划模式来解决这类行业的空间配置。这一对模式的解给出了具有最小行业总成本的配置方案和与之相应的产品和原料在各个区位的影子价格。尤其是作者依据空间价格均衡找出了原模式与对偶模式的解之间的关系,这些关系是行业空间配置优化的效率条件。 相似文献
22.
Pavlos S. Kanaroglou 《The Professional geographer》1994,46(3):359-368
Samples used to estimate discrete choice models in geography and regional science are typically assumed to be simple random samples. This assumption is not always met with existing samples. Furthermore, data collection is usually less costly if a stratified sampling strategy is adopted. Existing sampling theory suggests that stratified sampling can affect the consistency of parameter estimates. This paper reviews the salient points of this theory and relates theory to practice by means of a simple example on housing choice by elderly. 相似文献
23.
地基处理方案的模糊优化 总被引:17,自引:1,他引:17
本文首先分析了地基处理方案选择时的多层次因素关系树,然后利用模糊数学的原理对各个影响因素进行定量评价,从而使所选择的地基处理方案达到整体最优。 相似文献
24.
First of all, the necessity of establishing financial centres is expounded. The establishment of financial centres has a lot of benefits to the world economic development, China's economy and the occupied cities. The location conditions of financial centres may be summarized as follows: the location of trade centre, the factors of geographical position, the circumstances of finance, etc.. We consider that the first batch of financial centres in China should be established in the eastern cities of China. So 9 eastern cities in China are chosen as the spare financial centres. According to the location conditions of financial centres, 12 indices are chosen and the method of synthetic weighted average is used to find the best locations of financial centres. The conclusions are that the grade A financial centres should be in Shanghai and the grade B should be in Tianjin and Guangzhou. 相似文献
25.
Fulong Wu 《Geoforum》2007,38(2):379-392
Rather than being abandoned along with the demise of the centrally planned economy, city planning as a profession is flourishing in China. New hybrid plans such as strategic development plans (concept plans) have been invented, and the planning procedure has become more flexible. Design competition and planning consultancy are widespread. This paper examines the development of new strategic development plans and design competition. It is argued that city planning has been re-orientated from a technical rationale, i.e. allocating state development projects to the city, to the imperative derived from market-oriented development, i.e. consolidating competitiveness during inter-city competition. The contradiction between market and planning is that while the status of city planning has been raised and its approach is becoming more strategic, the actual functionality of city planning has become more instrumental. 相似文献
26.
在通道中利用“阂值”命令创建选择X-255。在通道混合中创建任意色阶区间选择X1~X2。利用通道混合“减去”模式中“缩放”“补偿值”实现深度自由选择。 相似文献
27.
The article discusses the effects of changing the parking situation in the surrounding of shopping centres on consumers store
choice behaviour. To get insight into these effects a hierarchical logit model of parking lot and store choice behaviour is
estimated and validated. The research is based on before-and-after data of supermarket visitors collected in a major regional
shopping centre in a suburban area in The Netherlands.
The model is estimated using the before data. At the level of the supermarkets the estimated hierarchical logit model performs
very well. The model is less accurate at the level of parking lots but still performs satisfactory. Significant attributes
are a constant representing the characteristics of the supermarket, the distance between supermarket and parking lot, the
number of parking spaces per parking lot, the location of the parking lot vis-à-vis the origin of the consumer, and the availability
of supermarket trolley facilities at the parking lot. Validating the model by reproducing the after data yields less satisfactory
results. Especially the model does not perform very well on predicting parking lot choice.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
28.
为提高连续小波变换识别位场场源准确度,研究噪声对场源识别结果的影响和尺度因子优选方法问题。根据连续小波变换识别位场场源的基本原理,用该方法对不同噪声水平的合成数据进行场源识别,分析噪声对于场源识别结果的影响,研究小波变换的尺度因子对噪声压制的效果,讨论连续小波变换进行场源识别时尺度因子的选取方法。理论模型和实测资料场源识别结果表明,噪声会降低连续小波变换场源识别结果的准确度,笔者提出的尺度因子优选方法能有效压制噪声干扰,提高场源识别结果的准确度。 相似文献
29.
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