915 research outputs found

    Evolving Charge Correlations in a Hybrid Model with both Hydrodynamics and Hadronic Boltzmann Descriptions

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    Correlations related to local charge conservation provide insight into the creation and evolution of up, down and strange charges in the quark-gluon plasma. Here, the evolution of charge correlations is overlaid onto a hydrodynamic calculation for the regions where temperature exceed 155 MeV, then transferred and carried through a microscopic model of the hadronic stage. Thus, for the first time, charge correlations are evolved consistently with a full state-of-the-art description of a heavy-ion collision. The charge correlations are projected onto charge balance functions, which characterize such correlations in the final state, and are presented as a function of relative rapidity and relative azimuthal angle for Au/Au collisions. The role of the hadronic stage is investigated. Calculation of the contribution to charge-separation observables related to the chiral magnetic effect are also presented. Calculations are compared to data from the STAR Collaboration at RHIC (Relativistic Heavy Ion Collider) data when possible.Comment: 29 pages 5 figure

    Boundary Integral Equation Method for Electrostatic Field Prediction in Piecewise-Homogeneous Electrolytes

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    This thesis presents a method to predict electrostatic fields, potentials, and currents in regions containing piecewise-homogeneous electrolytes. Additionally, an efficient electric field calculation is presented. A boundary integral equation is formulated for the boundary potentials and currents and is discretized using the Locally Corrected Nyström method. Solution convergence with respect to the mesh discretization and basis order is investigated. The techniques are validated through analysis of problems with either analytic solutions, with published data, or with other solution methods

    Master of Science

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    thesisThis thesis focuses on the design, modeling, fabrication, and testing of a ?ying and walking robot, called the Dynamic Underactuated Flying-Walking (DUCK) robot. The DUCK robot combines a high-mobility ?ying platform, such as a quadcopter (quadrotor helicopter), with passive-dynamic legs to create a versatile system that can ?y and walk. One of the advantages of using passive-dynamic legs for walking is that additional actuators are not needed for terrestrial locomotion, therefore simplifying the design, reducing overall weight, and decreasing power consumption. First, a mathematical model is developed for the DUCK robot, where the modeling combines the passive-dynamic walking mechanism with the swinging mass of the aerial platform. Second, simulations based on the model are used to help guide the design of two prototype robots, speci?cally to tailor the shape of the feet and the dimensions of the passive-dynamic walking mechanism. Third, an energy analysis is performed to compare the performances between ?ying and walking. More specifically, simulation results show that continuous active walking has a comparable energy efficiency to that of flying for the two prototype designs. For design Version 1, it is estimated that the robot is able to walk up to 1600 meters on a 30kJ battery (standard Li-Po battery) with a cost of transport of 1.0, while the robot can potentially fly up to 1800 meters horizontally with the weight of its legs and up to 2300 meters without the weight of its legs. Design Version 2 is estimated to be able to walk up to 4600 meters on a 30kJ battery with a cost of transport of .50, while it could fly up to 2600 meters with the weight of its legs or 4300 meters without its legs. The cost of transport of flying is estimated to be .89 in all scenarios. Finally, experimental results demonstrate the feasibility of combining an aerial platform with passive-dynamic legs to create an effective flying and walking robot. Two modes of walking are experimentally demonstrated: (1) passive walking down inclined surfaces for low-energy terrestrial locomotion and (2) active (powered) walking leveraging the capabilities of the flying platform, where thrust from the quadcopter's rotors enables the DUCK robot to walk on flat surfaces or up inclined surfaces

    Routeing in military tourism: gamification as an implementation proposal

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    This dissertation approaches three main concepts, routeing applied to tourism, Military Tourism as a segment of Cultural Tourism and Gamification as a tool for tourist fruition, with the aim at establishing a link between them. Following a literature review from various authors in each of these areas, and after the establishment of a firm conceptual base, this project investigates the possible links between them. In this specific case the application of the benefits of gamification to promote the development of Military Tourism products and their organisation in military themed tourism routes. In conclusion this dissertation presents a guiding model explaining the use of different forms of game based technology to develop different Military Tourism products and how this tool can aid in the organisation in a Military Tourism Route

    An appropriate level of risk: Balancing the need for safe livestock products with fair market access for the poor

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    This paper examines the role of livestock products as commodities of trade, responding to the demand and higher prices that many external markets offer, and at the same time providing important contributions to the development process in poorer countries. It highlights that this opportunity is not without its threats: much of the Western world has, over the last half century in particular, invested substantial amounts of money in controlling and eradicating many infectious diseases of livestock, and in building up healthy and highly productive animals, the products derived from which earn them very large sums of money on world markets. Such countries are not willing to take risks that could threaten their livestock industries, and their domestic and export markets that maintain high animal health and food safety standards. The study builds on a number of 'success stories', examples where developing countries have succeeded in exporting livestock or livestock products to external markets. An analysis of the factors governing their success revealed some commonalities: all were driven by strong private sector partners who contributed capital, management expertise and entrepreneurial flair; most concerned livestock products, rather than live animals, which matched the market's requirements; many had developed strong brand identities which had become synonymous with quality, safety and dependability; and many were vertically integrated systems, incorporating small and medium scale out-grower producers. Often these successes have been achieved despite the absence of effective support from the public sector, such as national veterinary authorities. One of the key findings of this study is the disparity between the push for global harmonisation of animal health standards for trade, and the lack of capacity of developing countries, particularly LDCs, to meet these standards. The study considers how this might be rectified and concludes that building capacity of regional bodies to create regional centres of excellence with regard to SPS matters may be the most practical way forward.Livestock Production/Industries,

    Information and Communications Technology (ICT) Assessment Teams for First Responders in Humanitarian Assistance/Disaster Relief (HA/DR) Missions

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    Immediately following a natural disaster requiring Humanitarian Assistance/Disaster Relief (HA/DR), a myriad of organizations respond. Typically, these early responders send small assessment teams to determine critical needs, which are then paired with the resources available. The needs can range from basic subsistence (food, shelter, and water) to transportation and infrastructure, yet the paramount factor among each team is the need to communicate. To assist in this effort, an Information and Communications Technology (ICT) assessment team using standardized tactics, techniques, procedures and training to maximize effectivenessand comprised of members from multiple organizationscould provide a shared prospective among member groups that could ultimately produce a more objective and complete communications assessment. This in turn, could be transmitted immediately to the global response community via appropriate information sharing portals. As no such model exists at present, our research attempts to pioneer and explore this concept and capability by exploring and providing an outline of an ICT assessment team model. In this thesis, we examine its potential structure, methodologies, and equipment, as well as discuss prospective funding sources, and include in the appendices, checklists derived from our findings, thus improving and hastening early responders understanding of a disasters communications situation.http://archive.org/details/informationndcom109456768Lieutenant, United States Nav

    Wondertopes

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    Positive geometries were introduced by Arkani-Hamed--Bai--Lam as a method of computing scattering amplitudes in theoretical physics. We show that a positive geometry from a polytope admits a log resolution of singularities to another positive geometry. Our result states that the regions in a wonderful compactification of a hyperplane arrangement complement, which we call wondertopes, are positive geometries. A familiar wondertope is the curvy associahedron, which tiles the moduli space of pointed stable rational curves. Thus our work generalizes the known positive geometry structure on this moduli space.Comment: 33 pages, 10 figures; comments welcome

    A Review of Epistemology and Subject Areas in MIS Research

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    The purpose of this paper is to classify the most cited papers in Management Information Systems (MIS) by theoretical perspective and subject area. The determination of the underlying theoretical perspective of these papers facilitates and verifies the dominance of positivist perspectives. Our analysis indicates that 74% of the most cited articles are positivist and 26% are interpretivist. The presence of a significant percentage of interpretive work suggests that differing theoretical perspectives are being considered relevant to solving the problems identified in the current research streams. Our results also indicated User Satisfaction and Instrument Development and Group Support Systems as the most cited articles subject areas, 16% and 14% respectively. The significance of these subject areas promotes and supports that systems is the foundation of MIS

    Optimizing NILC Extractions of the Thermal Sunyaev-Zeldovich Effect with Deep Learning

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    All-sky maps of the thermal Sunyaev-Zel'dovich effect (SZ) tend to suffer from systematic features arising from the component separation techniques used to extract the signal. In this work, we investigate one of these methods known as needlet internal linear combination (NILC) and test its performance on simulated data. We show that NILC estimates are strongly affected by the choice of the spatial localization parameter (Γ\Gamma), which controls a bias-variance trade-off. Typically, NILC extractions assume a fixed value of Γ\Gamma over the entire sky, but we show there exists an optimal Γ\Gamma that depends on the SZ signal strength and local contamination properties. Then we calculate the NILC solutions for multiple values of Γ\Gamma and feed the results into a neural network to predict the SZ signal. This extraction method, which we call Deep-NILC, is tested against a set of validation data, including recovered radial profiles of resolved systems. Our main result is that Deep-NILC offers significant improvements over choosing fixed values of Γ\Gamma.Comment: 18 pages, 9 figures, 2 Tables, Accepted by Ap
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