949 resultados para CHANGE-POINT
Resumo:
The philosophical promise of community development to “resource and empower people so that they can collectively control their own destinies” (Kenny 1996:104) is no doubt alluring to Indigenous Australia. Given the historical and contemporary experiences of colonial control and surveillance of Aboriginal bodies, alongside the continuing experiences of socio-economic disadvantage, community development reaffirms the aspirational goal of Indigenous Australians for self-determination. Self-determination as a national policy agenda for Indigenous Australians emerged in the 1970s and saw the establishment of a wide range of Aboriginal community-controlled services (Tsey et al 2012). Sullivan (2010:4) argues that the Aboriginal community controlled service sector during this time has, and continues to be, instrumental to advancing the plight of Indigenous Australians both materially and politically. Yet community development and self-determination remain highly problematic and contested in how they manifest in Indigenous social policy agendas and in practice (Hollinsworth 1996; Martin 2003; McCausland 2005; Moreton-Robinson 2009). Moreton-Robinson (2009:68) argues that a central theme underpinning these tensions is a reading of Indigeneity in which Aboriginal and Torres Strait Islander people, behaviours, cultures, and communities are pathologised as “dysfunctional” thus enabling assertions that Indigenous people are incapable of managing their own affairs. This discourse distracts us from the “strategies and tactics of patriarchal white sovereignty” that inhibit the “state’s earlier policy of self-determination” (Moreton-Robinson 2009:68). We acknowledge the irony of community development espoused by Ramirez above (1990), that the least resourced are expected to be most resourceful.; however, we wish to interrogate the processes that inhibit Indigenous participation and control of our own affairs rather than further interrogate Aboriginal minds as uneducated, incapable and/or impaired...
Resumo:
We propose the use of optical flow information as a method for detecting and describing changes in the environment, from the perspective of a mobile camera. We analyze the characteristics of the optical flow signal and demonstrate how robust flow vectors can be generated and used for the detection of depth discontinuities and appearance changes at key locations. To successfully achieve this task, a full discussion on camera positioning, distortion compensation, noise filtering, and parameter estimation is presented. We then extract statistical attributes from the flow signal to describe the location of the scene changes. We also employ clustering and dominant shape of vectors to increase the descriptiveness. Once a database of nodes (where a node is a detected scene change) and their corresponding flow features is created, matching can be performed whenever nodes are encountered, such that topological localization can be achieved. We retrieve the most likely node according to the Mahalanobis and Chi-square distances between the current frame and the database. The results illustrate the applicability of the technique for detecting and describing scene changes in diverse lighting conditions, considering indoor and outdoor environments and different robot platforms.
Resumo:
This paper aims to develop a meshless approach based on the Point Interpolation Method (PIM) for numerical simulation of a space fractional diffusion equation. Two fully-discrete schemes for the one-dimensional space fractional diffusion equation are obtained by using the PIM and the strong-forms of the space diffusion equation. Numerical examples with different nodal distributions are studied to validate and investigate the accuracy and efficiency of the newly developed meshless approach.
Resumo:
Aim: To quantify the consequences of major threats to biodiversity, such as climate and land-use change, it is important to use explicit measures of species persistence, such as extinction risk. The extinction risk of metapopulations can be approximated through simple models, providing a regional snapshot of the extinction probability of a species. We evaluated the extinction risk of three species under different climate change scenarios in three different regions of the Mexican cloud forest, a highly fragmented habitat that is particularly vulnerable to climate change. Location: Cloud forests in Mexico. Methods: Using Maxent, we estimated the potential distribution of cloud forest for three different time horizons (2030, 2050 and 2080) and their overlap with protected areas. Then, we calculated the extinction risk of three contrasting vertebrate species for two scenarios: (1) climate change only (all suitable areas of cloud forest through time) and (2) climate and land-use change (only suitable areas within a currently protected area), using an explicit patch-occupancy approximation model and calculating the joint probability of all populations becoming extinct when the number of remaining patches was less than five. Results: Our results show that the extent of environmentally suitable areas for cloud forest in Mexico will sharply decline in the next 70 years. We discovered that if all habitat outside protected areas is transformed, then only species with small area requirements are likely to persist. With habitat loss through climate change only, high dispersal rates are sufficient for persistence, but this requires protection of all remaining cloud forest areas. Main conclusions: Even if high dispersal rates mitigate the extinction risk of species due to climate change, the synergistic impacts of changing climate and land use further threaten the persistence of species with higher area requirements. Our approach for assessing the impacts of threats on biodiversity is particularly useful when there is little time or data for detailed population viability analyses. © 2013 John Wiley & Sons Ltd.