4,680 research outputs found

    Exploring pathways for sustainable water management in river deltas in a changing environment

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    Exploring adaptation pathways into an uncertain future can support decisionmaking in achieving sustainable water management in a changing environment. Our objective is to develop and test a method to identify such pathways by including dynamics from natural variability and the interaction between the water system and society. Present planning studies on long-term water management often use a few plausible futures for one or two projection years, ignoring the dynamic aspect of adaptation through the interaction between the water system and society. Our approach is to explore pathways using multiple realisations of transient scenarios with an Integrated Assessment Meta Model (IAMM). This paper presents the first application of the method using a hypothetical case study. The case study shows how to explore and evaluate adaptation pathways. With the pathways it is possible to identify opportunities, threats, timing and sequence of policy options, which can be used by policymakers to develop water management roadmaps into the future. By including the dynamics between the water system and society, the influence of uncertainties in both systems becomes clearer. The results show, among others, that climate variability rather than climate change appears to be important for taking decisions in water management

    On Secure Implementation of an IHE XUA-Based Protocol for Authenticating Healthcare Professionals

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    The importance of the Electronic Health Record (EHR) has been addressed in recent years by governments and institutions.Many large scale projects have been funded with the aim to allow healthcare professionals to consult patients data. Properties such as confidentiality, authentication and authorization are the key for the success for these projects. The Integrating the Healthcare Enterprise (IHE) initiative promotes the coordinated use of established standards for authenticated and secure EHR exchanges among clinics and hospitals. In particular, the IHE integration profile named XUA permits to attest user identities by relying on SAML assertions, i.e. XML documents containing authentication statements. In this paper, we provide a formal model for the secure issuance of such an assertion. We first specify the scenario using the process calculus COWS and then analyse it using the model checker CMC. Our analysis reveals a potential flaw in the XUA profile when using a SAML assertion in an unprotected network. We then suggest a solution for this flaw, and model check and implement this solution to show that it is secure and feasible

    Defect-unbinding and the Bose-glass transition in layered superconductors

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    The low-field Bose-glass transition temperature in heavy-ion irradiated Bi_2Sr_2CaCu_2O_8+d increases progressively with increasing density of irradiation-induced columnar defects, but saturates for densities in excess of 1.5 x10^9 cm^-2. The maximum Bose-glass temperature corresponds to that above which diffusion of two-dimensional pancake vortices between different vortex lines becomes possible, and above which the ``line-like'' character of vortices is lost. We develop a description of the Bose-glass line that is in excellent quantitative agreement with the experimental line obtained for widely different values of track density and material parameters.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Let

    Backward Erosion Piping Model Verification Using Cases in China and The Netherlands

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    Backward erosion piping, the process of shallow pipe development in the sandy foundation of levees, is a threat to the safety of levees in countries like China and the Netherlands. Several models are available to predict the required critical head for this phenomenon, i.e. Bligh’s model and Sellmeijer’s model. Well-documented breach cases, which unfortunately are rare, give the opportunity to verify the applicability of prediction models. In this paper two piping cases in China and one piping case in the Netherlands have been described and analyzed in order to compare the outcome of prediction models with this actual data. It is concluded that Bligh’s model is easy to apply due to a small number of input parameters. The use of this model as a first step in safety assessment is limited due to the fact that it can give lower critical head predictions than the more accurate Sellmeijer model. On the other hand, the Sellmeijer model is more difficult to apply due to its sensitivity to permeability and grain size parameters. This sensitively results in a wide range for the critical head due to large uncertainties in the parameters. A probabilistic approach for parameter estimation combined with a more detailed soil investigation where necessary is recommended for a more accurate piping prediction

    Vortex Solid-Liquid Transition in Bi2_{2}Sr2_{2}CaCu2_{2}O8+δ_{8+\delta} with a High Density of Strong Pins

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    The introduction of a large density of columnar defects in %underdoped Bi2_{2}Sr2_{2}CaCu2_{2}O8+δ_{8+\delta} crystals does not, at sufficiently low vortex densities, increase the irreversibility line beyond the first order transition (FOT) field of pristine crystals. At such low fields, the flux line wandering length rwr_{w} behaves as in pristine %Bi2_{2}Sr2_{2}CaCu2_{2}O8+δ_{8+\delta} crystals. Next, vortex positional correlations along the cc--axis in the vortex Bose glass at fields above the FOT are smaller than in the low--field vortex solid. Third, the Bose-glass-to-vortex liquid transition is signaled by a rapid decrease in c-axis phase correlations. These observations are understood in terms of the ``discrete superconductor'' model.Comment: 4 pages, 4 figures Submitted to Phys. Rev. B Rapid Comm. 16-1-2004 Revised version 18-3-200

    Tools and verification

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    This chapter presents different tools that have been developed inside the Sensoria project. Sensoria studied qualitative analysis techniques for verifying properties of service implementations with respect to their formal specifications. The tools presented in this chapter have been developed to carry out the analysis in an automated, or semi-automated, way. We present four different tools, all developed during the Sensoria project, exploiting new techniques and calculi from the Sensoria project itself

    Українська шляхта між польським та українським етносами

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    Appearance and existence of the Ukrainian gentry relates to the traditions of Polish political culture, so during the whole period of its life it was between the Ukrainian and the Polish ethnic groups. Polanisation of the Ukrainian gentry begins at the date when some of the Ukrainian territories become a part of Poland and strengthens after Cossack revolution in the middle and at the end of the 16th century. Especially this process becomes effective at the beginning of the 18th century when a great part of gentry from other Polish lands migrates to Pravoberezhia (right-banked Ukraine). Nevertheless, having captured upper class and partially middle class of the Ukrainian gentry, polanisation mainly influenced consciousness and less religion of the lower class of the Ukrainian gentry. As for ethnoculture and language local gentry was mostly Ukrainian and it assimilated numerous Polish gentlemen-immigrants
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