The rough sets feature selection for trees recognition in color aerial images using genetic algorithms

Selecting a set of features which is optimal for a given task is the problem which plays an important role in a wide variety of contexts including pattern recognition, images understanding and machine learning. The concept of reduction of the decision table based on the rough set is very useful for feature selection. In this paper, a genetic algorithm based approach is presented to search the relative reduct decision table of the rough set. This approach has the ability to accommodate multiple criteria such as accuracy and cost of classification into the feature selection process and finds the effective feature subset for texture classification . On the basis of the effective feature subset selected, this paper presents a method to extract the objects which are higher than their surroundings, such as trees or forest, in the color aerial images. The experiments results show that the feature subset selected and the method of the object extraction presented in this paper are practical and effective.

Problem and solution trees : a practical approach for identifying potential interventions to improve population nutrition

Population nutrition problems have a diversity of contributory factors and, ideally, multi-sectoral solutions should be developed by the relevant stakeholders, based on a common understanding of these factors. The problem and solution tree approach is a participatory process of working through the layers of determinants and then developing potential interventions for a specific issue, using the available data and expertise. We tailored this approach for non-communicable disease-related nutrition problems in Pacific Islands and applied it in several countries. The process led to the identification of a considerable range of determinants of unhealthy diets and potential interventions to improve the situation. This practical approach also offered the additional benefit of developing stakeholder awareness in the issues. Problem trees are a relatively simple tool to implement, easy to adapt to differing needs, can generate a wealth of information and can be more widely used.

Ecology of Powerful Owls (Ninox strenua) in contrasting habitats of the Yarra Valley Corridor, Victoria, Australia

In this research I investigated ecological attributes of Powerful Owls (Ninox strenua) in a continuum of habitats throughout the Yarra Valley corridor of Victoria, Australia. These habitats ranged from a highly urbanized parkland (the Yarra Valley Metropolitan Park) to a relatively undisturbed closed forest (Toolangi State Forest). Different aspects of the owls' ecology were investigated at six sites to determine whether their behaviour changed when they occupied habitats with different levels of urbanization and disturbance. The ecological attributes investigated were habitat utilization and habitat requirements (for both roosting and nesting), adult behaviour (through radio-tracking), juvenile behaviour and dispersal (through radio tracking), diet (through analysing regurgitated food pellets) and breeding success rates. A number of methods were used to capture adult Powerful Owls. These are described and their effectiveness discussed. The types of radio-transmitters and colour bands used for identification of owls are also described. The results showed that Powerful Owls are present and successfully breed in urban and suburban areas and that they can tolerate moderate levels of disturbance. However, Powerful Owls do require sites with high prey densities, roost trees and trees with suitable breeding hollows. In comparison with Powerful Owls living elsewhere in forests, the urban owls displayed higher tolerance levels to disturbance and were less selective in terms of habitat usage and diet. Home range sizes of urban Powerful Owls also appeared much smaller than those of the forest-dwelling Powerful Owls. This is probably due to the high prey densities in the urban areas. The ecology of the Powerful Owl is compared with that of two owl species from North America, the Northern Spotted Owl (Strix occidentalis caurind) and the Great Horned Owl (Bubo virginianus). In particular, I compared the similarities and differences in habitat requirements and breeding successes in different habitats for the three species. Overall, it would appear that urban areas can support Powerful Owls providing some old-growth trees are maintained to provide nest hollows. Implications for the long-term management of Powerful Owls in urban areas are also discussed.

Other communities : Box mistletoe (Amyema miquelii) parasitism is not detrimental to the health of grey box (Eucalyptus microcarpa) trees at a regional scale

Mistletoes are hemiparasites that occur worldwide in many types of forest, woodland and shrubland ecosystems (Watson 2001). Some species are regarded as pests due to their detrimental effects on host species (Hawksworth 1983; Reid & Yan 2000). Heavy infestations can affect the growth, productivity and form of host trees, and may cause host death (Reid et al. 1994; Shaw et al.2004, 2008). In south-eastern Australia, mistletoes often are visibly obvious in trees along roadsides, in paddocks and on the margins of open forests; and concerns have been expressed about their potentially detrimental effects on host trees.Despite this, little quantitative information is available on the effects of mistletoes on tree health and mortality (Reid et al. 1994). Are detrimental effects widespread or localized? A first step is to assess whether trees parasitized by mistletoe are less healthy than those without such parasites. Here, we investigate the relationship between parasitism by Box Mistletoe (Amyema miquelii (Lehm. ex Miq.) Tiegh.), a common species in south-eastern Australia, and the health of trees of a widespread host species, Grey Box (Eucalyptus microcarpa (Maiden) Maiden), across a large geographic region.