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基于随机模型基准的Helmert方差分量估计 被引量:5
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作者 汪平 刘长建 《测绘科学技术学报》 北大核心 2007年第3期213-215,共3页
在多类观测数据联合平差中,存在某类观测值的验前协方差阵正确而其他类不正确的情况,传统Helmert方差分量估计在求解此类问题时没有对正确的验前协方差阵加以区别,从而造成正确的随机模型经估计后同样也被调整。针对上述情况,首先分析了... 在多类观测数据联合平差中,存在某类观测值的验前协方差阵正确而其他类不正确的情况,传统Helmert方差分量估计在求解此类问题时没有对正确的验前协方差阵加以区别,从而造成正确的随机模型经估计后同样也被调整。针对上述情况,首先分析了Helmert方差分量估计迭代收敛结果的实质,然后提出了随机模型基准的概念,并推导了基于随机模型基准的Helmert方差分量估计公式。经计算表明,新公式完全可行,可以用于解决实际问题。 展开更多
关键词 随机模型基准 HELMERT方差分量估计 严密公式 简化公式
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Balance of Datum Land Prices Among Cities Based on the City Gravitation Model and Stochastic Diffusion Equation 被引量:2
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作者 LIU Yaolin LIU Yang +1 位作者 LAN Zeying XIAYin LIU Wei 《Geo-Spatial Information Science》 2008年第1期71-78,共8页
A balance of urban datum land prices is achieved to harmonize regional land prices and make the prices truly reflect different economic development levels and land prices among cities. The current piecewise linear int... A balance of urban datum land prices is achieved to harmonize regional land prices and make the prices truly reflect different economic development levels and land prices among cities. The current piecewise linear interpolation balance method widely used has two drawbacks that always lead to an unsatisfactory balance among some cities. When the excess of land price in the central city to the surrounding zone reaches a certain degree, land price in the circumjacent city is not only consistent with the local land grade and land use level, but also influenced by the diffusion of land price in the central city. Thus, a new balanced scheme of datum land prices based on the city gravitation model and stochastic diffusion equation is brought forward. Finally, the new method is examined in the practice of datum land price balance in Hubei Province, China. 展开更多
关键词 datum land price balance city gravitation model stochastic diffusion equation
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