108 resultados para Optimum-path forests


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Health is inherently 'ecological' and the natural environment plays a crucial role in human health and well-being. Yet we do not necessarily design, manage or market such areas in ways that acknowledge this link. This paper draws on recent research by a Deakin University team exploring the links between use of and involvement in the maintenance of forests/woodlands, and health and well-being outcomes. Qualitative and quantitative methods have been used to collect data from forest/woodland users and tram volunteers contributing to management and maintenance of such areas, concerning their perceptions of the impacts of the experience
on their health and well-being. In two of the projects, samples of 'users' and 'volunteers' were compared with samples 'non-users' and 'non-volunteers'. Several of the studies included the use of scales of self-rated health, social cohesion, and frequency of use of medical services.The studies have identified a range of perceived physical, mental and social health benefits resulting from use of and/or engagement with forests/woodlands. Study findings have implications for design, management and marketing of such areas, since they identity factors influencing use of and engagement with such areas, and have the potential to promote more widespread recognition of the value of such areas and more commitment to them by individuals, communities and governments. The challenge for us is to build on this research base to more clearly Signpost the mutually beneficial links between forest and woodland ecosystems and human health and well-being, creating new and better pathways to a healthy future.

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Low cost robotic detectors are a promising new approach to combat the disturbing landmine crisis. In this paper a low-cost robotic solution is proposed, we present several control techniques used to improve the precision of the robotic motion. A P and PD controller is applied, and it is concluded that a cascaded control system provides a more stable and accurate response. Two search patterns for landmine detection are considered, rectangular and spiral, these are used to analyse the effectiveness of the control system.

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In this paper we examine the problem of finding an optimal position for a receiver node in a single-hop sensor network. The basic idea is to minimize the network energy consumption according to a particular network cost function. Our contribution is to simply show the effect of signal path loss rates and sensor weighting on the optimal receiver position.

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Land use change has occurred rapidly in southwestern Victoria over the last decade and is expected to continue, albeit at a slower pace. One of these changes has been the development of 'new forests', that is industrial and farm forestry plantations and environmental plantings. Some of the challenges that these land use changes pose for water and natural resource managers are discussed. Land use change is expected to substantially reduce potential water yield in four of the region's seven drainage basins (A).

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The blackwater model was developed to predict adverse water quality associated with flooding of the Barmah-Millewa Forests on the River Murray. Specifically, the model examines the likelihood and severity of blackwater events—high dissolved organic carbon associated with low dissolved oxygen. The Barmah-Millewa Forests are dominated by an overstorey of River Red Gum (Eucalyptus camaldulensis) and the litter from these trees contributes a substantial proportion of the pulse of dissolved organic matter released from the floodplain during flooding. This model examines rates of litter accumulation and decay on the floodplain (prior to and during flooding), rates of carbon leaching, microbial degradation, oxygen consumption, reaeration processes and the effects of flow on the concentrations of dissolved organic carbon and dissolved oxygen in the water column (both on the floodplain and in the river channel downstream). The model has been calibrated with data from two blackwater events that have taken place in these forests within the last 5 years. Scenario testing with the model highlights the particularly important roles of flow and temperature in the development of anoxia. Pooled floods and those in the warmest months of the year are substantially more likely to result in blackwater events than floods in cooler times of the year and involving more water exchange between the river channel and the floodplain.

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Wireless sensor networks represent a new generation of real-time  embedded systems with significantly different communication constraints from the traditional networked systems. With their development, a new attack called a path-based DoS (PDoS) attack has appeared. In a PDoS attack, an adversary, either inside or outside the network, overwhelms sensor nodes by flooding a multi-hop endto- end communication path with either replayed packets or injected spurious packets. In this article, we propose a solution using mobile agents which can detect PDoS attacks easily.

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Wireless sensor networks represent a new generation of real-time embedded systems with significantly different communication constraints from the traditional networked systems. With their development, a new attack called a path-based DoS (PDoS) attack has appeared. In a PDoS attack, an adversary, either inside or outside the network, overwhelms sensor nodes by flooding a multi-hop end-to end communication path with either replayed packets or injected spurious packets. Detection and recovery from PDoS attacks have not been given much attention in the literature. In this article, we propose a solution using mobile agents which can detect PDoS attacks easily and efficiently and recover the compromised nodes.

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Nestedness in biota as a function of species richness – biota of depauperate assemblages being non-random subsets of richer biotas – has been widely documented in recent years (see Wright et al. 1998, Oecologia 113: 1–20). Ordering sites by richness maximizes nestedness indices; however, ordering by other criteria such as area or isolation may be more ecologically interpretable. We surveyed birds in true fragments (35 in all), and in "reference areas" in large extant forest blocks (30 locations), of the same range of areas (10, 20, 40, 80 ha). The avifauna was divided into "bush birds"– species dependent on forest and woodland, and "open country" species. We looked at nestedness in four data sets: "bush birds" in fragments and reference areas, and "all birds" in fragments and in reference areas. All data sets were significantly nested. Ordering by area in all cases was not significantly less nested than ordering by richness. Ordering by area in fragments was significantly greater than in reference areas, but the differences in standardized nestedness indices were small (<15%). We identified those birds that had distributions among fragments that conformed strongly with area, those that were more randomly distributed and some species that were more likely to occupy the smallest fragments. Among the latter was a hyperaggressive, invasive, colonial native species (noisy miner Manorina melanocephala). A suite of small, insectivorous birds were more likely to strongly conform with expected distributions in relation to area, which was consistent with observations of their vulnerability to the effects of the noisy miner in smaller fragments.

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Purpose – The paper attempts to project the future trend of the gender wage gap in Great Britain up to 2031.
Design/methodology/approach – The empirical analysis utilises the British Household Panel Study Wave F together with Office for National Statistics (ONS) demographic projections. The methodology combines the ONS projections with assumptions relating to the evolution of educational attainment in order to project the future distribution of human capital skills and consequently the future size of the gender wage gap.
Findings – The analysis suggests that gender wage convergence will be slow, with little female progress by 2031 unless there is a large rise in returns to female experience.
Originality/value – The paper has projected the pattern of male and female skill acquisition together with the associated trend in wages up to 2031.

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The aim of this paper was to develop a process for the production of DAG from butterfat through glycerolysis and short-path distillation and to evaluate the physical properties of the DAG in comparison with the original butterfat. Chemical glycerolysis produced a mixture of acylglycerols containing DAG together with MAG and TAG. From the mixture of glycerolysis products, MAG were removed through three consecutive distillations (vacuum <0.001 mbar) at 150°C. TAG were separated from DAG by distillation at 210°C, which gave a product with more than 80% DAG in the distillates. Distillation temperatures had significant effects on acyl migration. The formation of desirable 1,3-DAG was favored at higher temperatures. Under 210°C distillation, the equilibrium ratio of 6∶4 was obtained between 1,3-DAG and 1,2(2,3)-DAG. The FA profile of the DAG product was relatively similar to the original butterfat. The total DAG recovery was around 77% in the pilot-scale production. The different patterns of m.p. were observed between butterfat and the DAG fraction produced as well as the MAG fraction collected. Solid fat content profiles of the DAG fraction and its mixtures with rapeseed oil possessed trends similar to those of the corresponding butterfat and its mixtures with rapeseed oil. Compared with butterfat, the DAG fraction behaved differently in its thermal profiles, crystallization patterns, and rheological properties; for example, the dropping point was 13°C higher for the latter than for the former, and the crystal pattern was mostly β form for the latter, whereas the former was the β′ form.

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SWAT cannot accurately simulate the seasonal fluctuations or the long-term trend of the Leaf Area Index (LAI) of evergreen forests. This deficiency has detrimental impacts for the prediction of interception and transpiration, two processes that have a significant influence on catchment water yield. This paper details the integration of the forest growth model 3-PG with SWAT to improve the simulation of LAI for evergreen forests. The integrated model, called SWAT/3-PG, was applied to the Woady Yaloak River Catchment in southern Australia where eucalyptus forests and pine plantations account for 30% of the total land use. SWAT/3-PG simulated the LAI of eucalypts and pines more accurately and realistically than the original version of SWAT. Forest LAI simulated by SWAT/3-PG agreed reasonably well with estimates of forest LAI derived independently from a Landsat satellite image. SWAT/3- PG has considerable value as a tool that managers can utilise to predict the impacts of land use change in catchments where evergreen forests are prevalent.

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BGP (Border Gateway Protocol) is a fundamental component of the current Internet infrastructure. However, BGP is vulnerable to a variety of attacks, since it cannot ensure the authenticity of the path attributes announced by BGP routers. Despite several solutions have been proposed to address this vulnerability, none of them is operational in real-world due to their immense impact on original BGP. In this paper, we propose a Deployable Path Validation Authentication scheme, which can effectively validate the path of BGP. Through analysis and simulation we show that this scheme has little impact on the performance and memory usage for the original BGP, and can be adopted in practice as an operational approach.