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Spatio-temporal model based on Markov random fields and its application to forest ecology

基于马尔可夫随机场的时空模型及其在森林生态中的应用

基本信息

批准号：
12640108
负责人：
MASE Shigeru
金额：
$ 1.28万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2001
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640108/
关键词：
Markov random field Maximum pseudo-likelihood estimator approximate MLE MCMC method Gibbs sampler canopy height tropical forest plant ecology マルコフ確立場最大擬似尤度推定量近時最尤度推定量空間統計学森林生態系ポデーシャル関数最尤推定 BCIデータ

项目摘要

Markov random field models are fitted to 12 years data of canopy heights of neo-tropical forests of Barro Corollado islands, Panama. Canopy heights are binarized, under and over 20m. From various experiments taking account of neighbouring patterns of trees to potential functions, it is verified that Markov random field model can model binary canopy patterns fairly well using 1-bocly, 2-body and 4-body patterns simultaneously. Model parameters are first estimated by the maximum pseudo-likelihood method and they are refined by a MQMC Newton-Raphson refinement clue to Huang and Ogata. Among 12 years data, 8 data shows fairly good fittings and 2 years good fittings. 2 years data cannot show good fittings, probably due to temporal drastic changes of forest systems. But it is seen that temporal unstableness recovers quickly, showing the ecological stableness of the forest. As a result, it is verified that Markov random field model can represent such forest, system. The analysis 43 under the process of submitting to an appropriate journal. Also the head investigator published a first Japanese book on spatial statistics including Markov random field in 2001.

用马尔可夫随机场模型拟合了巴拿马巴罗科罗拉多群岛新热带森林冠层高度的12年资料。冠层高度被二值化，低于和超过20米。通过将相邻树型引入势函数的各种试验，验证了马尔可夫随机场模型能较好地同时模拟1-bocly、2-bocly和4-bocly树型二元林冠格局。模型参数首先通过最大伪似然法估计，然后通过Huang和Ogata的MQMC Newton-Raphson细化线索进行细化。在12年的数据中，8年的数据显示为较好的配件，2年的配件良好。2年的数据不能显示良好的拟合，可能是由于森林系统的时间急剧变化。但时间上的不稳定性恢复较快，反映了森林的生态稳定性。结果表明，马尔可夫随机场模型可以很好地描述这类森林系统。该分析43正在提交给适当的期刊的过程中。此外，首席研究员于2001年出版了第一本关于空间统计的日本书籍，其中包括马尔可夫随机场。