1,671 research outputs found

    The Kato square root problem on vector bundles with generalised bounded geometry

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    We consider smooth, complete Riemannian manifolds which are exponentially locally doubling. Under a uniform Ricci curvature bound and a uniform lower bound on injectivity radius, we prove a Kato square root estimate for certain coercive operators over the bundle of finite rank tensors. These results are obtained as a special case of similar estimates on smooth vector bundles satisfying a criterion which we call generalised bounded geometry. We prove this by establishing quadratic estimates for perturbations of Dirac type operators on such bundles under an appropriate set of assumptions.Comment: Slight technical modification of the notion of "GBG constant section" on page 7, and a few technical modifications to Proposition 8.4, 8.6, 8.

    Towards a generic autonomic architecture for legacy resource management

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    Half a decade has passed since the objectives and benefits of autonomic computing were stated, yet even the latest system designs and deployments exhibit only limited and isolated elements of autonomic functionality. From an autonomic computing standpoint, all computing systems ā€“ old, new or under development ā€“ are legacy systems, and will continue to be so for some time to come. In this paper, we propose a generic architecture for developing fully-fledged autonomic systems out of legacy, non-autonomic components, and we investigate how existing technologies can be used to implement this architecture

    A normalisation procedure for biaxial bias extension tests

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    Biaxial Bias Extension tests have been performed on a plain-weave carbon fibre engineering fabric. The test results have been normalised using both the upper and lower bound method proposed by Potluri et al. and also using a novel alternative normalisation method based on energy arguments. The normalised results from both methods are compared and discussed

    Asian Elephants as Agricultural Pests: Damages, Economics of Control and Compensation in Sri Lanka

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    Despite growing attention to crop and property damage caused by the Asian elephant, uncertainty exists about the magnitude of this problem. This paper explores the nature and magnitude of this problem of Sri Lanka. An economic analysis of individual farmersā€™ decisions to control elephants is provided. Government policies to assist farmers to cope with the elephant pest problem are assessed. Appropriate compensation schemes for farmers are seen as potentially more effective for conserving elephants in Sri Lanka than legal prohibitions on killing of elephants. Issues raised have wider relevance than merely to Sri Lanka or Asian elephants

    Household water security through stored rainwater and consumer acceptability: a case study of the Anuradhapura District

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    Rainwater harvesting has increased in popularity in Sri Lanka over the past two decades due to the number of water supply projects funded by the government and non-governmental organizations (NGOs). The stored rainwater can provide accessible, reliable, timely and adequate supplies of water to households but there are uncertainties as to safety, in terms of water quality, and consumer acceptability. A study was, therefore, conducted in the Anuradhapura District, in the dry zone, to assess consumer acceptability of stored rainwater for household purposes and to conduct rainwater quality tests in a laboratory. The majority of households in Anuradhapura meet their drinking water requirements from protected wells (59.6 %). Prior to the project, people greatly preferred open wells as a source of domestic water, followed by tubewells, because they believed that water in open wells is of good quality and drinkable. However, stored rainwater has become the priority source now, especially through roof rainwater harvesting (RRWH), which is used during the dry periods. The study revealed that more than 85 % of households use stored rainwater for drinking although some have concerns over the quality and only drink it after boiling. The easy accessibility of water and the assurance by the project team that it is of good quality are the main reasons that people are willing to drink it. The acceptability of stored rainwater for consumption was very high in water-scarce areas and with the increasing distance to the nearest and alternative sources of good-quality water. Of those who felt that they had adequate water, 84 % of the sample households found it adequate in the wet season but only 21 % in the dry season. Water quality analysis revealed that the chemical and physical quality of stored rainwater is within the acceptable range with respect to Sri Lankan Standards, SLS: 614, for potable water quality (SLIS 1983). Other domestic water sources exceeded standards for electrical conductivity, total alkalinity, hardness, ammonium nitrogen, fluorides and total iron. However, stored rainwater was of lower biological quality than other domestic water sources.Length: pp.87-97Domestic waterWater securityWater harvestingWater qualityRural areasCase studies

    Progress on the hybridization of cultivated lentil Lens culinaris Medik. and wild species Lens tomentosus Ladizinsky

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    Non-Peer ReviewedThe domestication of lentil has produced bottleneck effects resulting in a narrow genetic basis which has resulted in reduced levels of resistance to biotic and abiotic stresses relative to its wild relatives. Phenotypic variability studies have identified wild lentil germplasm with resistance to anthracnose (Colletotrichum spp.), ascochyta blight (Ascochyta lentis), stemphylium blight (Stemphylium botryosum) and Orobanche spp. root-holoparasitic infection. To increase genetic diversity and resistance to biotic and abiotic stresses in new cultivars, introgression of desirable genes from crop wild relatives is necessary. Current evidences suggest seven taxa in the genus Lens Mill.: L. culinaris (ssp. culinaris and ssp. orientalis), L. odemensis, L. ervoides, L. nigricans, L. tomentosus and L. lamottei. Morphologically, the wild lentil species L. tomentosus most resembles L. orientalis although it can be distinguished as having a hairy pod. Previous attempts of crossing cultivated lentil L. culinaris with the wild species L. tomentosus, have failed to produce viable seeds, as with time growing embryos are gradually degraded and shrivelled, and non-viable seeds are formed; consequently an embryo rescue technique has been employed with limited success. However, this technique is time consuming, and also requires controlled growing environments and highly skilled technical personal. Using very comprehensive phenotyping technique, we have crossed cultivated lentil cultivar ā€˜Indian headā€™ with L. tomentosus and successfully produced viable F1 generation and it has currently being evaluated for phenological and morphological characteristics. Our results suggest successful results can be achieved by selecting phenotypically resembling lentil species as parents as an initial step

    A goal-based approach to policy refinement

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    As the interest in using policy-based approaches for systems management grows, it is becoming increasingly important to develop methods for performing analysis and refinement of policy specifications. Although this is an area that researchers have devoted some attention to, none of the proposed solutions address the issue of deriving implementable policies from high-level goals. A key part of the solution to this problem is having the ability to identify the operations, available on the underlying system, which can achieve a given goal. This paper presents an approach by which a formal representation of a system, based on the Event Calculus, can be used in conjunction with abductive reasoning techniques to derive the sequence of operations that will allow a given system to achieve a desired goal. Additionally it outlines how this technique might be used for providing tool support and partial automation for policy refinement. Building on previous work on using formal techniques for policy analysis, the approach presented here applies a transformation of both policy and system behaviour specifications into a formal notation that is based on Event Calculus. Finally, it shows how the overall process could be used in conjunction with UML modelling and illustrates this by means of an example. 1
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