181 research outputs found
Exploring intelligent service migration in vehicular networks
Mobile edge clouds have great potential to address the challenges in vehicular networks by transferring storage and computing functions to the cloud. This brings many advantages of the cloud closer to the mobile user, by installing small cloud infrastructures at the network edge. However, it is still a challenge to efficiently utilize heterogeneous communication and edge computing architectures. In this paper, we investigate the impact of live service migration within a Vehicular Ad-hoc Network environment by making use of the results collected from a real experimental test-bed. A new proactive service migration model which considers both the mobility of the user and the service migration time for different services is introduced. Results collected from a real experimental test-bed of connected vehicles show that there is a need to explore proactive service migration based on the mobility of users. This can result in better resource usage and better Quality of Service for the mobile user. Additionally, a study on the performance of the transport protocol and its impact in the context of live service migration for highly mobile environments is presented with results in terms of latency, bandwidth, and burst and their potential effect on the time it takes to migrate services
Exploring a new transport protocol for vehicular networks
The Future Internet will be very different from the current Internet. In particular, support for new networks such as vehicular networks, will be a key part of the new environment. Applications running on these networks will require low latency and high bandwidth, which must be provided in a highly mobile environment. The goal of this paper is to look at these issues as they have been addressed in the design and development of the Simple Lightweight Transport Protocol (SLTP) to support vehicular networking. The functions and workings of the protocol are examined in this paper as well as the ecosystem that is needed to provide low latency. A detailed set of preliminary results are presented and compared with a standard TCP implementation. SLTP was also ported to the Roadside Units of a Vehicle Ad-Hoc Network and results are presented for moving data to and from the Roadside Units. This work highlights the need for the Future Internet to place more resources at the edge of the core network to provide support for low latency in vehicular environments
Soft x-ray spectroscopy measurements of the p-like density of states of B in MgB2 and evidence for surface boron oxides on exposed surfaces
Soft X-ray absorption and fluorescence measurements are reported for the
K-edge of B in MgB2. The measurements confirm a high density of B
pxy(sigma)-states at the Fermi edge and extending to approximately 0.9 eV above
the edge. A strong resonance is observed in elastic scattering through a
core-exciton derived from out-of-plane pz(pi*)-states. Another strong
resonance, observed in both elastic and inelastic spectra, is identified as a
product of surface boron oxides.Comment: 7 pages total, 4 figures, submitted to Phys. Rev. Let
Study of the microwave electrodynamic response of MgB2 thin films
We present a study on the power dependence of the microwave surface impedance
in thin films of the novel superconductor MgB2. 500 nm thick samples exhibiting
critical temperatures ranging between 26 and 38 K are synthesized by an ex-situ
post-anneal of e-beam evaporated boron in the presence of an Mg vapor at 900 C.
Preliminary results on films grown in situ by a high rate magnetron sputtering
technique from stoichiometric MgB2 and Mg targets are also reported. Microwave
measurements have been carried out employing a dielectrically loaded niobium
superconducting cavity operating at 19.8 GHz and 4 K. The study shows that the
electrodynamic response of MgB2 films is presently dominated by extrinsic
sources of dissipation, appearing already at low microwave power, likely to be
ascribed to the presence of grain boundaries and normal inclusions in the
samples.Comment: 10 pages, 3 figures, proceedings of the conference EUCAS 2001,
submitted to Physica
A unique measles B3 cluster in the United Kingdom and the Netherlands linked to air travel and transit at a large international airport, February to April 2014
Rita de Sousa (Bolseira EUPHEM) - Investigadora do Departamento de Doenças Infeciosas do Instituto Ricardo JorgeThis report describes a joint measles outbreak investigation between public health officials in the United Kingdom (UK) and the Netherlands following detection of a measles cluster with a unique measles virus strain. From 1 February to 30 April 2014, 33 measles cases with a unique measles virus strain of genotype B3 were detected in the UK and the Netherlands, of which nine secondary cases were epidemiologically linked to an infectious measles case travelling from the Philippines. Through a combination of epidemiological investigation and sequence analysis, we found that measles transmission occurred in flight, airport and household settings. The secondary measles cases included airport workers, passengers in transit at the same airport or travelling on the same flight as the infectious case and also household contacts. This investigation highlighted the particular importance of measles genotyping in identifying transmission networks and the need to improve vaccination, public health follow-up and management of travellers and airport staff exposed to measles.info:eu-repo/semantics/publishedVersio
High temporal stability of supercurrents in MgB(2) materials
Fine grained polycrystalline samples of MgB(2) superconductor were
synthesized from the elements to contain < 5 % of impurity phases, according to
X-ray powder diffractometry. The superconductive transition was sharp with a
midpoint Tc = 38.5 K. The magnetization in the vortex state was studied as a
function of applied field H, temperature T, and time t. From the equilibrium
magnetization, the London penetration depth was obtained. The supercurrent
density J(T,H,t) in the vortex state (derived from the irreversible
magnetization) decreases approximately linearly with T, in contrast to the
quasi-exponential falloff in high-Tc superconductors. The current is highly
stable in time, with normalized decay rates S = -d ln(J)/d ln(t) well below
those in high-Tc materials. These results are compared with those of other
superconductors.Comment: PDF file containing text and 6 figures, 12 pages tota
Differentiating Schizophrenia from Bipolar Illness on 18 F FDG PET CT Based on white Matter Metabolism; an under-Utilised Parameter
18F-FDG PET/CT positron emission tomography studies (FDG-PET) have shown similar cortico-limbic metabolic dysregulation in bipolar disorder and schizophrenia, with hypoactive prefrontal cortex coupled with hyperactive anterior limbic areas. However, it is not clear whether white matter metabolism connecting these regions is differently affected in the two disorders. Forty eight patients with schizophrenia mean age ± S.D] 31.6 ± 7.8 and 56 patients with bipolar disorder [mean age±S.D] 46.2 ± 8.9 underwent an 18F-FDG PET/CT scan. Normalized datasets the two groups of patients were compared on a voxel-by-voxel basis using a two-sample t statistic test as implemented in SPM8, and adding age as covariate. Group differences were assessed applying a threshold of p<0.0005. White matter metabolic rates significantly differed between schizophrenia and bipolar disorder, whereas no differences were shown for cortical activity. This is the first 18F-FDG PET/CT to our best knowledge, directly comparing subjects with schizophrenia to those with bipolar disorder. It reports decreased activity in the center of large fronto-temporal and cerebellar white matter tracts in patients with schizophrenia in respect to those with bipolar disorder. This feature may characterize and differentiate the regional brain metabolism of the two illnesses
A serious game architecture for green mobility
Good driving behavior is a significant factor for road safety and green mobility. A countermeasure to overcome the coarse driving behavior and a methodology to captivate optimal driving traits are discussed in this work. For which, the serious games concept was exploited to improvise the driver performance by deploying diversified game logics (scores, incentives and live game for performance evolution) on a smartphone-based user interface. The application was tested in ASTA ZERO (Active Safety Test Area) in Sweden. The tests comprised of variations (good and bad driving behavior) in driving pattern for analyzing the impact of the application on the driver performance
Superconducting MgB(2) films via precursor post-processing approach
Superconducting MgB(2) films with Tc = 38.6 K were prepared using a
precursor-deposition, ex-situ post-processing approach. Precursor films of
boron, ~0.5 micrometer thick, were deposited onto Al(2)O(3) (102) substrates by
e-beam evaporation; a post-anneal at 890 deg C in the presence of bulk MgB(2)
and Mg metal produced highly crystalline MgB(2) films. X-ray diffraction
indicated that the films exhibit some degree of c-axis alignment, but are
randomly oriented in-plane. Transport current measurements of the
superconducting properties show high values of the critical current density and
yield an irreversibility line that exceeds that determined by magnetic
measurements on bulk polycrystalline materials.Comment: PDF file with 10 pages total, including 4 figure
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