We propose a hierarchical log Gaussian Cox process (LGCP) for point patterns, where a set of points x affects another set of points y but not vice versa. We use the model to investigate the effect of large trees to the locations of seedlings. In the model, every point in x has a parametric influence kernel or signal, which together form an influence field. Conditionally on the parameters, the influence field acts as a spatial covariate in the intensity of the model, and the intensity itself is a non-linear function of the parameters. Points outside the observation window may affect the influence field inside the window. We propose an edge correction to account for this missing data. The parameters of the model are estimated in a Bayesian framework using Markov chain Monte Carlo (MCMC) where a Laplace approximation is used for the Gaussian field of the LGCP model. The proposed model is used to analyze the effect of large trees on the success of regeneration in uneven-aged forest stands in Finland.
翻译:我们建议对点图案使用一个等级日志 Gaussian Cox 进程( LGCP ), 即一组点 x 影响另一组点, 反之亦然。 我们使用该模型来调查大树对幼苗位置的影响。 在模型中, x 中的每个点都有一个参数影响内核或信号, 从而共同形成影响场。 在参数上, 影响场作为模型强度的空间共变, 强度本身是参数的非线性函数 。 观察窗口外的点可能会影响窗口内的影响场 。 我们建议对缺少的数据进行边缘校正。 该模型的参数在Bayesian 框架中使用Markov 链条 Monte Carlo( MC ) 估算, 在那里, LGCP 模型的高山场使用拉普特近值。 拟议的模型用于分析大树对不均匀森林再生成功的影响 。