2,826 research outputs found

    Impact of Correlated Mobility on Delay-Throughput Performance in Mobile Ad-Hoc Networks

    Get PDF
    Abstract—We extend the analysis of the scaling laws of wireless ad hoc networks to the case of correlated nodes movements, which are commonly found in real mobility processes. We consider a simple version of the Reference Point Group Mobility model, in which nodes belonging to the same group are constrained to lie in a disc area, whose center moves uniformly across the network according to the i.i.d. model. We assume fast mobility conditions, and take as primary goal the maximization of pernode throughput. We discover that correlated node movements have huge impact on asymptotic throughput and delay, and can sometimes lead to better performance than the one achievable under independent nodes movements. I. INTRODUCTION AND RELATED WORK In the last few years the store-carry-forward communication paradigm, which allows nodes to physically carry buffered dat

    Part time faculty’s enforcement of academic integrity policies

    Get PDF
    The research examined material on academic integrity/honor codes in higher education, faculty enforcement of honor codes, faculty perceptions of honor codes, perceptions of full time vs. part time faculty of the higher education experience, higher education leadership, honor codes in business degree programs, student course evaluations and faculty reactions to student course evaluations

    Polarized Fusion. Can Polarization Help to Increase the Energy Output of Fusion Reactors?

    Get PDF
    Since more than 60 years scientists are working on the idea to produce energy from nuclear fusion of light particles like the Hydrogen isotopes. In the meantime, the energy output of e.g. tokamak reactors was increased by five orders and modern experiments like JET are approaching the border for energy production. The international ITER collaboration is preparing the first fusion reactor that will produce about ten times more energy, compared to the energy that is needed to run the experiment. Today, the laser-induced inertial fusion reached the same level and experiments at the National Ignition Facility (NIF) in California, USA, demonstrate a ratio between produced and induced energy about one at the end of 2013.1 In parallel, it is discussed since 1970 to use nuclear polarized fuel to increase the total cross sections of the different fusion reactions.2 The energy gain of fusion reactors does not depend linearly on the total cross section. Depending on the different concepts for nuclear fusion, magnetic confinement or inertial fusion, the energy gain This is an Open Access article published by World Scientific Publishing Company. It is distributed under the terms of the Creative Commons Attribution 3.0 (CC-BY) License. Further distribution of this work is permitted, provided the original work is properly cited. 1660112-1 Int. J. Mod. Phys. Conf. Ser. 2016.40. Downloaded from www.worldscientific.com by UNIVERSITY OF FERRARA on 04/19/16. For personal use only. R. Engels & G. Ciullo is improved above average. M. Temporal et al. have shown, e.g., that the energy gain of laser-induced inertial fusion might be increased by a factor four, or that the necessary laser power can be reduced by 20 %, if the nuclear fuel was polarized before.3 The downsized laser power will reduce the costs of the corresponding project by a reasonable amount. In addition, the differential cross sections can be modified so that it will be possible to focus the ejectiles, e.g. the neutrons, on special wall areas. In a tokamak this can be used to concentrate the neutron flux to special outer parts of the blanket, where the cooling can be improved and the neutrons be used for Tritium production via the exothermic reaction 6Li+n → 4He+t.4 At the same time, less cooling is needed for the inner parts of the blanket that allows to bring the magnetic field coils closer to the fusion plasma. The increased magnetic field in the plasma will increase the energy gain additionally. Another option of polarized fuel is a new kind of plasma diagnostic inside a tokamak. In combination with modern Nuclear Magnetic Resonance technologies (NMR) anisotropies in the plasma can be measured to learn more about the different plasma mode

    The OLYMPUS Internal Hydrogen Target

    Get PDF
    An internal hydrogen target system was developed for the OLYMPUS experiment at DESY, in Hamburg, Germany. The target consisted of a long, thin-walled, tubular cell within an aluminum scattering chamber. Hydrogen entered at the center of the cell and exited through the ends, where it was removed from the beamline by a multistage pumping system. A cryogenic coldhead cooled the target cell to counteract heating from the beam and increase the density of hydrogen in the target. A fixed collimator protected the cell from synchrotron radiation and the beam halo. A series of wakefield suppressors reduced heating from beam wakefields. The target system was installed within the DORIS storage ring and was successfully operated during the course of the OLYMPUS experiment in 2012. Information on the design, fabrication, and performance of the target system is reported.Comment: 9 pages, 13 figure

    Network Awareness of P2P Live Streaming Applications

    Get PDF
    Early P2P-TV systems have already attracted millions of users, and many new commercial solutions are entering this market. Little information is however available about how these systems work. In this paper we present large scale sets of experiments to compare three of the most successful P2P-TV systems, namely PPLive, SopCast and TVAnts. Our goal is to assess what level of "network awareness" has been embedded in the applications, i.e., what parameters mainly drive the peer selection and data exchange. By using a general framework that can be extended to other systems and metrics, we show that all applications largely base their choices on the peer bandwidth, i.e., they prefer high-bandwidth users, which is rather intuitive. Moreover, TVAnts and PPLive exhibits also a preference to exchange data among peers in the same autonomous system the peer belongs to. However, no evidence about preference versus peers in the same subnet or that are closer to the considered peer emerges. We believe that next-generation P2P live streaming applications definitively need to improve the level of network-awareness, so to better localize the traffic in the network and thus increase their network-friendliness as wel

    Development of a surgical stereo endoscopic image dataset for validating 3D stereo reconstruction algorithms

    Get PDF
    In the last decades, endoscopic stereo images have been exploited to retrieve tissue surface information of the surgical site using 3D reconstruction algorithms. The application of such algorithms in Computer Assisted Surgery (CAS) tools for Minimally Invasive Surgery (MIS) requires a robust validation process in order to guarantee reliability and safety. 3D reconstruction algorithms are commonly evaluated comparing their result with respect to a reference Ground Truth (GT). However, few datasets providing endoscopic images and GT are openly available. Considering the increasing necessity of surgical datasets, the aim of this work is the generation of an Endoscopic Abdominal Stereo (EndoAbS) dataset composed of stereo-images with associated GT for 3D stereo-reconstruction algorithm validation. To recreate the surgical scenario, a polyurethane surgical phantom abdomen was built. Images were captured with a stereo-endoscope, while for acquiring the GT a laser scanner (calibrated with respect to the stereoendoscope) was used. This dataset is openly available on-line for the benefit of the CAS community

    Reality Check: Today’s Child Labor Issues in U.S. Tobacco Farming

    Get PDF
    Rebecca Ciullo's & Carrie A. Picardi's poster about child labor issues in U.S. tobacco farming
    corecore