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1.
The spatial analysis literature recognizes three sources of aggregation error, termed Source A, Source B, and Source C, which affect models relying on distance measurements between populations and facilities. We consider these effects with respect to aggregating from census enumeration areas to census tracts, on a popular location model. We identify a further source of aggregation error, which we dub Source D error, arising from the representation of facility sites by discrete points. Source D effects are of the same magnitude as Source A and B combined, much greater than Source C effects. Source D error is further significant, because, unlike Source A and B error, it can be eliminated only by disaggregating .
La littérature sur Vanalyse spatiale reconnaît trois sources d'erreur d'agrégation appelées erreurs de source A, B, et C. Ces erreurs influencent les modèles qui reposent sur des mesures de distance entre des populations et des installations. On considère les effets d'agrégation des secteurs de dénombrement en secteurs de recensement sur un modèle de localisation courant. On identifie une quatrième source d'erreur d'agrégation appelée erreur de source D. Cette erreur découle de la représentation des sites des installations par des points discrets. Ses effets sont du même ordre de grandeur que ceux des sources A et B combinées et beaucoup plus grands que les effets de source G. L'erreur de source D est d'autant plus significative à cause du fait que, contrairement aux erreurs de source A et B, elle ne peut être éliminée que par la désagrégation .  相似文献   
2.
《增校清朝进士题名碑录·附引得》进士籍贯刊误述论   总被引:2,自引:0,他引:2  
文章以列表的方式,论述了《增校清朝进士题名碑录.附引得》中存在的6种进士籍贯刊误现象,即:省际进士籍贯刊载互误、省内进士县际籍贯互误、进士籍贯标注字误、以俗名标注进士籍贯、以府名标注进士籍贯及以府、县二级标注进士籍贯。文章并较细致地探讨了该书出现这些刊误的原因。  相似文献   
3.
本文重点从韵文的角度,讨论《明清以来苏州社会史碑刻集》的若干校点问题。  相似文献   
4.
The black reaction, invented in 1873 by Camillo Golgi (1843-1926), was the first technique to reveal neurons in their entirety, i.e. with all their processes. This important development passed unnoticed at first and only received wide international attention after a long delay. The Golgi stain was widely employed for almost thirty years and was directly responsible for major advances in our knowledge of the microscopic anatomy of the nervous system, as well as in other fields of study. In the hands of other researchers, the black reaction provided vital evidence that helped to establish the neuron theory. The Golgi stain was almost forgotten in the period between the two World Wars, but the introduction of the electron microscope to neurocytological research revived its use around the middle of the twentieth century. Today, the black reaction is still used extensively not only in combination with electron microscopy, but also as an autonomous technique in studies on the evolution, ontogeny, and organization of the nervous system.  相似文献   
5.
基于北京市六环内住房租赁样本的交易数据,本文以北京地铁为例,采用空间回归模型实证探讨轨道交通对合租和整租这两种不同方式下的住房租赁价格的影响。结果表明:①基于轨道交通的就业可达性对于租赁价格会产生显著的增值效应,租客愿意为就业可达性较好的住房支付溢价租金。②地铁站点密度对整租的租赁价格具有正向影响,对合租无显著影响,而地铁换乘线路变量未对租赁价格产生显著影响。③轨道交通对合租和整租住房租赁价格的影响随着距离增加呈现差异化的演变规律。合租方式的租赁价格的影响随着实际路网距离的增加呈现单调递减,距站点500m范围内影响最大;而整租方式呈现倒“U”形变化,在500-1500m范围内增值效应最大。针对研究结果,建议政府加大租赁住房供给的同时要充分考虑轨道交通要素,精准施策以实现公共资源的空间高效配置。  相似文献   
6.
蒲霞 《东南文化》2006,(1):59-61
以淳熙《新安志》、弘治《徽州府志》、道光《徽州府志》为主要参考,广征其他文献资料,对《永乐大典》所收《新安志》的七条记载中的错误作了订正。  相似文献   
7.
8.
In order to investigate replicability in scoring linear enamel hypoplasias 59 anterior teeth were evaluated by three observers. Hypoplasias were identified with low-power microscopy and by the unaided eye. Location on the tooth was determined through caliper and micrometer measurement as well as assignment to tooth ‘thirds’. Hypoplasia size was determined through measurement of episode width and comparison with a cast designed to categorize types of hypoplasia severity. Intra-observer analysis showed consistent scoring of about 65 per cent of individual hypoplasias between rounds, with high replicability in episode location, size and severity using all methods tested. Inter-observer error was similarly low for episode size and location, but consistent scoring of individual hypoplasias between observer pairs ranged between 21 and 39 per cent. It is likely that the most important factor in the low level of replicability is the slight size of the majority of hypoplasias involved. Thus, the results suggest that further work should be directed toward developing the minimum threshold for scoring episodes. Other issues include measures to control ‘drift’ in scoring procedures over time, and procedures to score large cervical hypoplasias in canines, which can appear as multiple episodes with magnification. Among the various scoring methods tested, determination of episode location was highly replicable using all three techniques. Episode width was also highly replicable using the micrometer, but the cast association proved less successful.  相似文献   
9.
以净初级生产力作为生态系统服务的综合测量指标,在经典柯布道格拉斯生产函数的基础上,运用协整与误差修正模型对1986-2010年黑龙江省生态系统服务对区域经济增长的影响进行了分析,并评估了净初级生产力的边际价格。结果表明,黑龙江省生态系统服务对区域经济增长具有明显的促进作用,净初级生产力每提高1%促进真实GDP增长0.0257%;在生态系统服务的影响下,黑龙江省经济系统以每年1.8%的速率将系统波动产生的非均衡状态向长期均衡状态调整,说明生态系统服务在促进经济增长的同时也保障了经济体系的稳定运行;在误差修正模型基础上得到的黑龙江省净初级生产力的边际价格为255.1元/106kgC(以1952年价格为基准),此价格主要受净初级生产力产出弹性的影响。  相似文献   
10.
清黄虞稷撰《千顷堂书目》著录明代书籍最富,也颇为后来学者所重视,屡经校正整理面世。然仍有挂漏讹误未及检出者。本文对书中史部人名之误,参考其它相关文献,比照勘核,订正六则。  相似文献   
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