10,010 research outputs found

    Quizbowl: Success In and Out of the Classroom, a Five Year Study

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    Scores of US and Canadian universities' undergraduate students participate in the SS-AAEA Quiz-bowl competition annually. Surveys of the 2001 through 2005 competition participants suggest how beneficial competition preparation and participation are in completing related university work and indicate factors which enhance chances of success in the competition.Teaching/Communication/Extension/Profession,

    Integrated design optimization research and development in an industrial environment

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    An overview is given of a design optimization project that is in progress at the GE Research and Development Center for the past few years. The objective of this project is to develop a methodology and a software system for design automation and optimization of structural/mechanical components and systems. The effort focuses on research and development issues and also on optimization applications that can be related to real-life industrial design problems. The overall technical approach is based on integration of numerical optimization techniques, finite element methods, CAE and software engineering, and artificial intelligence/expert systems (AI/ES) concepts. The role of each of these engineering technologies in the development of a unified design methodology is illustrated. A software system DESIGN-OPT has been developed for both size and shape optimization of structural components subjected to static as well as dynamic loadings. By integrating this software with an automatic mesh generator, a geometric modeler and an attribute specification computer code, a software module SHAPE-OPT has been developed for shape optimization. Details of these software packages together with their applications to some 2- and 3-dimensional design problems are described

    Immune-system inspired approach for decentralized multi-agent control

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    This paper contains the first steps towards the development of a fully decentralized system framework. The novel approach that has been taken is derived from the inherent properties of the immune system. An assessment of the proposed control architecture has been performed by comparison with a more typical approach under a search and suppress kind of mission for an unmanned fleet

    How Attitudes of Important Stakeholder Groups Can Influence Effective Water Quality Management

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    Preliminary results of a survey of Lincoln Lake agricultural and non-agricultural watershed residents as well as water quality regulators/specialists suggests discrepancies exists in different groups perceptions of water quality, the sources of water pollution, and the roles of local, county, state and federal officials in meeting water quality objectives.Resource /Energy Economics and Policy, Q25, Q53, Q59,

    Testing the equation of state for viscous dark energy

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    Some cosmological scenarios with bulk viscosity for the dark energy fluid are considered. Based on some considerations related to hydrodynamics, two different equations of state for dark energy are assumed, leading to power-law and logarithmic effective corrections to the pressure. The models are tested with the latest astronomical data from type Ia supernovae (Pantheon sample), measurements of the Hubble parameter HðzÞ, baryon acoustic oscillations and cosmic microwave background radiation. In comparison with the ΛCDM model, some different results are obtained and their viability is discussed. The power-law model shows some modest results, achieved under negative values of bulk viscosity, while the logarithmic scenario provide good fits in comparison to the ΛCDM model.Ministerio de Economía, Industria y Competitividad (project FIS2016-76363-P)Agencia de Gestión de Ayudas Universitarias y de Investigación (project 2017 SGR 247)CANTATA COST action (grant CA15117

    Cost and benefits of using best management practices to control non-point sources of pollution under environmental and economic uncertainty

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    The economy of northwest Arkansas, including the Lincoln Lake watershed (a sub-watershed of the Illinois River), relies greatly upon livestock and poultry production. The supply of production by-products is increasingly under scrutiny as one of the potential sources of water pollution in the region. In light of the recent economic crisis, methodologies that help producers to evaluate the environmental and economic impacts of several practices before implementing them may be a cost-effective means of increasing BMP adoption. This study uses stochastic dominance techniques to evaluate, environmentally and economically, ten best management practices (BMPs) combinations to lessen water pollution in the Lincoln Lake watershed. All BMP combinations analyzed were effective in reducing total phosphorous (TP) losses. However, six combinations also decreased net returns (NR) when compared to a baseline. This suggests that including BMPs in the bermudagrass production systems may lead to increased NR risk. Without additional incentives, producers will not likely implement these BMP combinations regardless of their TP reduction benefits. Although, as expected, rankings of BMP combinations in terms of TP or NR differed from each other, four scenarios established that environmental and economic goals are not necessarily conflicting; they may be complementary. Additionally, this analysis revealed that producers’ risk preferences did not matter when selecting among the top-four BMP combinations but it could be a factor for other less preferred scenarios.nonpoint pollution, watershed, best management practices, risk analysis, stochastic dominance, Environmental Economics and Policy, Risk and Uncertainty, Q25, Q53,

    Is exponential gravity a viable description for the whole cosmological history?

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    Here we analysed a particular type of F(R)F(R) gravity, the so-called exponential gravity which includes an exponential function of the Ricci scalar in the action. Such term represents a correction to the usual Hilbert-Einstein action. By using Supernovae Ia, Barionic Acoustic Oscillations, Cosmic Microwave Background and H(z)H(z) data, the free parameters of the model are well constrained. The results show that such corrections to General Relativity become important at cosmological scales and at late-times, providing an alternative to the dark energy problem. In addition, the fits do not determine any significant difference statistically with respect to the Λ\LambdaCDM model. Finally, such model is extended to include the inflationary epoch in the same gravitational Lagrangian. As shown in the paper, the additional terms can reproduce the inflationary epoch and satisfy the constraints from Planck data.Comment: 20 pages, 6 figures, analysis extended, version published in EPJ

    Gravitational Constant and Torsion

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    Riemann-Cartan space time U4U_{4} is considered here. It has been shown that when we link topological Nieh-Yan density with the gravitational constant then we get Einstein-Hilbert Lagrangian as a consequence.Comment: 8 page
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