4,407 research outputs found

    A Mobile Geo-Communication Dataset for Physiology-Aware DASH in Rural Ambulance Transport

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    Use of telecommunication technologies for remote, continuous monitoring of patients can enhance effectiveness of emergency ambulance care during transport from rural areas to a regional center hospital. However, the communication along the various routes in rural areas may have wide bandwidth ranges from 2G to 4G; some regions may have only lower satellite bandwidth available. Bandwidth fluctuation together with real-time communication of various clinical multimedia pose a major challenge during rural patient ambulance transport.; AB@The availability of a pre-transport route-dependent communication bandwidth database is an important resource in remote monitoring and clinical multimedia transmission in rural ambulance transport. Here, we present a geo-communication dataset from extensive profiling of 4 major US mobile carriers in Illinois, from the rural location of Hoopeston to the central referral hospital center at Urbana. In collaboration with Carle Foundation Hospital, we developed a profiler, and collected various geographical and communication traces for realistic emergency rural ambulance transport scenarios. Our dataset is to support our ongoing work of proposing "physiology-aware DASH", which is particularly useful for adaptive remote monitoring of critically ill patients in emergency rural ambulance transport. It provides insights on ensuring higher Quality of Service (QoS) for most critical clinical multimedia in response to changes in patients' physiological states and bandwidth conditions. Our dataset is available online for research community.Comment: Proceedings of the 8th ACM on Multimedia Systems Conference (MMSys'17), Pages 158-163, Taipei, Taiwan, June 20 - 23, 201

    Thermal effects on lattice strain in hcp Fe under pressure

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    We compute the c/a lattice strain versus temperature for nonmagnetic hcp iron at high pressures using both first-principles linear response quasiharmonic calculations based on the full potential linear-muffin-tin-orbital (LMTO) method and the particle-in-cell (PIC) model for the vibrational partition function using a tight-binding total-energy method. The tight-binding model shows excellent agreement with the all-electron LMTO method. When hcp structure is stable, the calculated geometric mean frequency and Helmholtz free energy of hcp Fe from PIC and linear response lattice dynamics agree very well, as does the axial ratio as a function of temperature and pressure. On-site anharmonicity proves to be small up to the melting temperature, and PIC gives a good estimate of its sign and magnitude. At low pressures, hcp Fe becomes dynamically unstable at large c/a ratios, and the PIC model might fail where the structure approaches lattice instability. The PIC approximation describes well the vibrational behavior away from the instability, and thus is a reasonable approach to compute high temperature properties of materials. Our results show significant differences from earlier PIC studies, which gave much larger axial ratio increases with increasing temperature, or reported large differences between PIC and lattice dynamics results.Comment: 9 figure

    Hydrodynamic Design of Integrated Bulbous Bowlsonar Dome for Naval Ships

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    Recently, the idea of bulbous bow has been extended from the commercial ships to the design of an integrated bow that houses a sonar dome for naval ships. In the present study, a design method for a particular set of requirements consisting of a narrow range of input parameters is presented. The method uses an approximate linear theory with sheltering effect for resistance estimation and pressure distribution, and correlation with statistical analysis from the existing literature and the tank-test results available in the public domain. Though the optimisation of design parameters has been done for the design speed, but the resistance performance over the entire speed range has been incorporated in the design. The bulb behaviourhas been discussed using the principle of minimisation of resistance and analysis of flow pattern over the bulb and near the sonar dome. It also explores the possible benefits arising out of new design from the production, acoustic, and hydrodynamic point of view. The results of this study are presented in the form of design parameters (for the bulbous bow) related tothe main hull parameters for a set of input data in a narrow range. Finally, the method has been used to design the bulbous bow for a surface combatant vessel

    Casimir Force for Arbitrary Objects Using the Argument Principle and Boundary Element Methods

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    Recent progress in the simulation of Casimir forces between various objects has allowed traditional computational electromagnetic solvers to be used to find Casimir forces in arbitrary three-dimensional objects. The underlying theory to these approaches requires knowledge and manipulation of quantum field theory and statistical physics. We present a calculation of the Casimir force using the method of moments via the argument principle. This simplified derivation allows greater freedom in the moment matrix where the argument principle can be used to calculate Casimir forces for arbitrary geometries and materials with the use of various computational electromagnetic techniques.Comment: 6 pages, 2 figure

    First-principles thermoelasticity of bcc iron under pressure

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    We investigate the elastic and isotropic aggregate properties of ferromagnetic bcc iron as a function of temperature and pressure by computing the Helmholtz free energies for the volume-conserving strained structures using the first-principles linear response linear-muffin-tin-orbital method and the generalized-gradient approximation. We include the electronic excitation contributions to the free energy from the band structures, and phonon contributions from quasi-harmonic lattice dynamics. We make detailed comparisons between our calculated elastic moduli and their temperature and pressure dependences with available experimental and theoretical data.Comment: 5 figures, 2 table
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