Detection of biomass change in a Norwegian mountain forest area using small footprint airborne laser scanner data

Different approaches for estimation of change in biomass between two points in time by means of airborne laser scanner data were tested. Both field and laser data were collected at two occasions on 52 sample plots in a mountain forest in southeastern Norway. In the first approach, biomass change was estimated as the difference between predicted biomass for the two measurement occasions. Joint models for the biomass at both occasions were fitted using different height and density variables from laser data as explanatory variables. The second approach modelled the observed change directly using the change in different variables extracted from the laser data as explanatory variables. In the third approach we modelled the relative change in biomass. The explanatory variables were also expressed as relative change between measurement occasions. In all approaches we allowed spline terms to be entered. We also investigated the aptness of models for which the residual variance was modeled by allowing it to be proportional to the area of the plot on which biomass was assessed. All alternative models were initially assessed by AIC. All models were also evaluated by estimating biomass change on the model development data. This evaluation indicated that the two direct approaches (approach 2 and 3) were better than relying on modeling biomass at both occasions and taking change as the difference between biomass estimates. Approach 2 seemed to be slightly better than approach 3 based on assessments of bias in the evaluation.     

解读的衰落:美国汉学的"哲学转向"

陈汉生和安乐哲对中国思想的哲学解释,尤其是对庄子的解释,其特点在于解读上的显著不足。陈汉生从分析哲学,安乐哲从后现代主义的先入为主的理论假设出发,对庄子进行了不恰当的解释。为了理解一个特定的中国思想家,我们必须在每种情况下对应于特定的思想家而开发出一种解读方式。以庄子的情况为例,我们的任务是发展出一种能够理解庄子的非理解的诠释学。我们的解读方式应该顺着一个特定的文本给我们提供的线索,它不应该被一个一般的理论所规定。