968 research outputs found

    Potential Implications of a Special Safeguard Mechanism in the WTO: the Case of Wheat

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    The Special Safeguard Mechanism (SSM) was a key issue in the July 2008 failure to reach agreement in the WTO negotiations under the Doha Development Agenda. It includes both price (P-SSM) and quantity-triggered measures (Q-SSM). This paper uses a stochastic simulation model of the world wheat market to investigate the effects of policy makers implementing policies based on the SSM rules. As expected, implementation of the Q-SSM is found to reduce imports, raise domestic prices, and boost mean domestic production in the SSM regions. However, rather than insulating countries that use it from price volatility, it would actually increase domestic price volatility in developing countries, largely by restricting imports when domestic output is low and prices high. We estimate that implementation of the Q-SSM would shrink average wheat imports by nearly 50% in some regions, with world wheat trade falling by 4.7%. The P-SSM is discriminatory against low price, developing country exporters and tends to contribute to additional producer price instability.Safeguard, SSM, WTO, volatility, wheat, food security, Agricultural and Food Policy, International Development, Q1, Q17, Q18,

    On the Importance of Frictional Energy Dissipation in the Prevention of Undesirable Self-Excited Vibrations in Gas Foil Bearing Rotor Systems

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    In this contribution, a nonlinear and fully coupled fluid–structure–rotor interaction model of a gas foil bearing rotor system is presented. Aiming at the reduction of undesirable self-excited vibrations, many common bearing designs feature a compliant and slightly movable multi-part foil structure inside the lubrication gap. The present paper discusses the general impact of frictional energy dissipation within the foil structure by adding equivalent viscous damping to the widespread simple elastic foundation model. For the computational analysis, the PDEs describing the fluid pressure distribution and the foil structure deformation field are spatially discretized using finite difference schemes. After suitable nondimensionalization of the resulting system of nonlinear ODEs, a corresponding state-space representation is deduced. Using numerical simulation tools, the stability of equilibrium points and the occurrence of self-excited vibrations are addressed and possible bifurcation scenarios are discussed. Summing up all results, frictional energy dissipation proves to be of crucial importance with regard to the reduction or prevention of undesirable self-excited vibrations in gas foil bearing rotor systems

    An Evaluation Framework for Adaptive Security for the IoT in eHealth

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    The work presented here has been carried out in the project ASSET – Adaptive Security for Smart Internet of Things in eHealth (2012–2015) funded by the Research Council of Norway in the VERDIKT programme. WThe work presented here has been carried out in the project ASSET – Adaptive Security for Smart Internet of Things in eHealth (2012–2015) funded by the Research Council of Norway in the VERDIKT programme. W—We present an assessment framework to evaluate adaptive security algorithms specifically for the Internet of Things (IoT) in eHealth applications. The successful deployment of the IoT depends on ensuring security and privacy, which need to adapt to the processing capabilities and resource use of the IoT. We develop a framework for the assessment and validation of context-aware adaptive security solutions for the IoT in eHealth that can quantify the characteristics and requirements of a situation. We present the properties to be fulfilled by a scenario to assess and quantify characteristics for the adaptive security solutions for eHealth. We then develop scenarios for patients with chronic diseases using biomedical sensors. These scenarios are used to create storylines for a chronic patient living at home or being treated in the hospital. We show numeric examples for how to apply our framework. We also present guidelines how to integrate our framework to evaluating adaptive security solutionsThe work presented here has been carried out in the project ASSET – Adaptive Security for Smart Internet of Things in eHealth (2012–2015) funded by the Research Council of Norway in the VERDIKT programme

    MINERvA neutrino detector response measured with test beam data

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    The MINERvA collaboration operated a scaled down replica of the solid scintillator tracking and sampling calorimeter regions of the MlNERvA detector in a hadron test beam at the Fermilab Test Beam Facility. This paper reports measurements with samples of protons, pions, and electrons from 0.35 to 2.0 GeV/c momentum. The calorimetric response to protons, pions, and electrons is obtained from these data. A measurement of the parameter in Birks\u27 law and an estimate of the tracking efficiency are extracted from the proton sample. Overall the data are well described by a Geant4-based Monte Carlo simulation of the detector and particle interactions with agreements better than 4% for the calorimetric response, though some features of the data are not precisely modeled. These measurements are used to tune the MINERvA detector simulation and evaluate systematic uncertainties in support of the MINERvA neutrino cross-section measurement program. (C) 2015 Published by Elsevier B.V
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