Semantic orientation extraction is the premise of text semantic tendency analysis and it is also the key process to obtain high precision and recall ratio. In this paper, basic semantic lexicon, conjunction corpus, an...
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ISBN:
(数字)9783642242823
ISBN:
(纸本)9783642242816;9783642242823
Semantic orientation extraction is the premise of text semantic tendency analysis and it is also the key process to obtain high precision and recall ratio. In this paper, basic semantic lexicon, conjunction corpus, and semantic distance between words are used to propose an approach of semantic orientation extraction of Chinese text based on multi-algorithm. Experiments show that the approach is better than some classical algorithms such as SO-PMI, HM, and measure of semantic distance between words.
Species distribution modelling (SDM) can help conservation by providing information on the ecological requirements of species at risk. We developed habitat suitability models at multiple spatial scales for a threatene...
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Species distribution modelling (SDM) can help conservation by providing information on the ecological requirements of species at risk. We developed habitat suitability models at multiple spatial scales for a threatened freshwater turtle, Emydoidea blandingii, in Ontario as a case study. We also explored the effect of background data selection and modelling algorithm selection on habitat suitability predictions. We used sighting records, high-resolution land cover data (25 m), and two SDM techniques: boosted regression trees;and maximum entropy modelling. The area under the receiver characteristic operating curve (AUC) for habitat suitability models tested on independent data ranged from 0.878 to 0.912 when using random background and from 0.727 to 0.741 with target-group background. E. blandingii habitat suitability was best predicted by air temperature, wetland area, open water area, road density, and cropland area. Habitat suitability increased with increasing air temperature and wetland area, and decreased with increasing cropland area. Low road density and open water increased habitat suitability, while high levels of either variable decreased habitat suitability. Robust habitat suitability maps for species at risk require using a multi-scale and multi-algorithm approach. If well used, SDM can offer insight on the habitat requirements of species at risk and help guide the development of management plans. Our results suggest that E. blandingii management plans should promote the protection of terrestrial habitat surrounding residential wetlands, halt the building of roads within and adjacent to currently occupied habitat, and identify movement corridors for isolated populations. (C) 2011 Elsevier GmbH. All rights reserved.
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