2,380 research outputs found
A scale-dependent cosmology for the inhomogeneous Universe
A scale-dependent cosmology is proposed in which the Robertson-Walker metric
and the Einstein equation are modified in such a way that , and
the age of the Universe all become scale-dependent. Its implications on the
observational cosmology are discussed.Comment: 7 pages, in RevTex. To be appeared in TAUP '9
Magnetic properties of neutrinos in high temperature SU(2)XU(1) gauge theory
We calculate the finite temperature self-energy for neutrinos in the presence
of a constant magnetic field in a medium in the unbroken
model. We obtain the exact dispersion relation for such neutrinos and find that
the thermal effective mass is modified by the magnetic field. We also find a
simple analytic expression for the dispersion relation and obtain the index of
refraction for large neutrino momentum.Comment: 13 pp, RevTeX, no figure
A Detailed Monte-Carlo Simulation for the Belle TOF System
We have developed a detailed Monte Carlo simulation program for the Belle TOF
system. Based on GEANT simulation, it takes account of all physics processes in
the TOF scintillation counters and readout electronics. The simulation
reproduces very well the performance of the Belle TOF system, including the
dE/dx response, the time walk effect, the time resolution, and the hit
efficiency due to beam background. In this report, we will describe the Belle
TOF simulation program in detail.Comment: To be submitted to NI
Transductive Segmentation of Textured Meshes
International audienceThis paper addresses the problem of segmenting a textured mesh into objects or object classes, consistently with user-supplied seeds. We view this task as transductive learning and use the flexibility of kernel-based weights to incorporate a various number of diverse features. Our method combines a Laplacian graph regularizer that enforces spatial coherence in label propagation and an SVM classifier that ensures dissemination of the seeds characteristics. Our interactive framework allows to easily specify classes seeds with sketches drawn on the mesh and potentially refine the segmentation. We obtain qualitatively good segmentations on several architectural scenes and show the applicability of our method to outliers removing
Toward sustainable express deliveries for online shopping: reusing packaging materials through reverse logistics
The COVID-19 pandemic has led to an increase in online purchases, which has inevitably raised the demand for express delivery packaging materials (EDPMs). This
study proposes a reverse logistics reuse framework that extends the EDPM life cycle by drawing on insights and conclusions from a review of the literature on supply
chain management and materials science to achieve a sustainable e-commerce system. A key benefit of reverse logistics is its effectiveness in exploiting opportunities
for resource reuse, which is preferred to recycling. By extending service life through resource optimization, recycling, and recovery processes, the novel reuse
framework based on reverse logistics can be implemented with minimal changes to existing forward logistics systems, potentially leading to more sustainable online
shopping. This study proposes a novel combination of reusable packaging materials and reverse logistics as a viable and more environmentally friendly practice, in line
with circular economy goals
E-D2HCP: enhanced distributed dynamic host configuration protocol
Mobile Ad Hoc Networks (MANETs) consist of mobile nodes equipped with wireless devices. They do not need any kind of pre-existent infrastructure and are about self-managed networks. MANETs enable communication between mobile nodes without direct links and across multihop paths. To ensure correct operation of the routing protocols, MANETs, have to assign unique IP addresses to the MANET devices. Furthermore, the address assignment is an important issue when dealing with MANET networks because the traditional approaches are not applicable without some changes, having to provide new protocols for the address auto-configuration. These schemes must take into account the properties of MANETs such as dynamic topology, limited resources or lack of infrastructure. In this paper, we propose a stateful scheme for dynamic allocation of IP addresses in MANETs entitled Extended Distributed Dynamic Host Configuration Protocol because it is based on a previous piece of work (D2CHP). This extension includes the network merging not covered by its predecessor. Simulation results show that the new protocol also improves D2HCP functionality in areas such as fault tolerance, concurrency and latency.Sección Deptal. de Sistemas Informáticos y ComputaciónFac. de Ciencias MatemáticasTRUEAgencia Espanola de Cooperacion Internacional para el Desarrollo (AECID, Spain) through Accion Integrada MAEC-AECID MEDITERRANEOSecurity Engineering Research Center - Ministry of Knowledge Economy (MKE, Korea)pu
Local threshold field for dendritic instability in superconducting MgB2 films
Using magneto-optical imaging the phenomenon of dendritic flux penetration in
superconducting films was studied. Flux dendrites were abruptly formed in a 300
nm thick film of MgB2 by applying a perpendicular magnetic field. Detailed
measurements of flux density distributions show that there exists a local
threshold field controlling the nucleation and termination of the dendritic
growth. At 4 K the local threshold field is close to 12 mT in this sample,
where the critical current density is 10^7 A/cm^2. The dendritic instability in
thin films is believed to be of thermo-magnetic origin, but the existence of a
local threshold field, and its small value are features that distinctly
contrast the thermo-magnetic instability (flux jumps) in bulk superconductors.Comment: 6 pages, 6 figures, submitted to Phys. Rev.
Cubic γ-phase U–Mo alloys synthesized by splat-cooling
U–Mo alloys are the most promising materials fulfilling the requirements of using low enriched uranium (LEU) fuel in research reactors. From a fundamental standpoint, it is of interest to determine the basic thermodynamic properties of the cubic γ-phase U–Mo alloys. We focus our attention on the use of Mo doping together with ultrafast cooling (with high cooling rates ≥106 K s−1), which helps to maintain the cubic γ-phase in U–Mo system to low temperatures and on determination of the low-temperature properties of these γ-U alloys. Using a splat cooling method it has been possible to maintain some fraction of the high-temperature γ-phase at room temperature in pure uranium. U-13 at.% Mo splat clearly exhibits the pure γ-phase structure. All the splats become superconducting with Tc in the range from 1.24 K (pure U splat) to 2.11 K (U-15 at.% Mo). The γ-phase in U–Mo alloys undergoes eutectoid decomposition to form equilibrium phases of orthorhombic α-uranium and tetragonal γ'-phase upon annealing at 500 °C, while annealing at 800 °C has stabilized the initial γ phase. The α-U easily absorbs a large amount of hydrogen (UH3 hydride), while the cubic bcc phase does not absorb any detectable amount of hydrogen at pressures below 1 bar and at room temperature. At 80 bar, the U-15 at.% Mo splat becomes powder consisting of elongated particles of 1–2 mm, revealing amorphous state
Security Issues in Mobile Ad Hoc Networks
Ad hoc networks are built on the basis of a communication without infrastructure and major investigations have focused on the routing and autoconfiguration problems. However, there is a little progress in solving the secure autoconfiguration problems in mobile ad hoc networks (MANETs), which has led to the proliferation of threats given the vulnerabilities of MANETs. It is clear that ad hoc networks have no centralized mechanism for defense against threats, such as a firewall, an intrusion detection system, or a proxy. Therefore, it is necessary that the defense of interests of each of the ad hoc components is the responsibility of each member node. This paper shows the most common threats to ad hoc networks and reviews several proposals that attempt to minimize some of these threats, showing their protection ability and vulnerabilities in light of the threats that might aris
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