7,862 research outputs found
RMD-QOSM: The NSIS Quality-of-Service Model for Resource Management in Diffserv
This document describes a Next Steps in Signaling (NSIS) Quality-of- Service (QoS) Model for networks that use the Resource Management in Diffserv (RMD) concept. RMD is a technique for adding admission control and preemption function to Differentiated Services (Diffserv) networks. The RMD QoS Model allows devices external to the RMD network to signal reservation requests to Edge nodes in the RMD network. The RMD Ingress Edge nodes classify the incoming flows into traffic classes and signals resource requests for the corresponding traffic class along the data path to the Egress Edge nodes for each flow. Egress nodes reconstitute the original requests and continue forwarding them along the data path towards the final destination. In addition, RMD defines notification functions to indicate overload situations within the domain to the Edge nodes
A fixed point theorem for L 1 spaces
We prove a fixed point theorem for a family of Banach spaces including notably L 1 and its non-commutative analogues. Several applications are given, e.g. the optimal solution to the "derivation problem” studied since the 1960
Delta Self-Consistent Field as a method to obtain potential energy surfaces of excited molecules on surfaces
We present a modification of the SCF method of calculating energies
of excited states, in order to make it applicable to resonance calculations of
molecules adsorbed on metal surfaces, where the molecular orbitals are highly
hybridized. The SCF approximation is a density functional method
closely resembling standard density functional theory (DFT), the only
difference being that in SCF one or more electrons are placed in higher
lying Kohn-Sham orbitals, instead of placing all electrons in the lowest
possible orbitals as one does when calculating the ground state energy within
standard DFT. We extend the SCF method by allowing excited electrons to
occupy orbitals which are linear combinations of Kohn-Sham orbitals. With this
extra freedom it is possible to place charge locally on adsorbed molecules in
the calculations, such that resonance energies can be estimated. The method is
applied to N, CO and NO adsorbed on different metallic surfaces and
compared to ordinary SCF without our modification, spatially
constrained DFT and inverse-photoemission spectroscopy (IPES) measurements.
This comparison shows that the modified SCF method gives results in
close agreement with experiment, significantly closer than the comparable
methods. For N adsorbed on ruthenium (0001) we map out a 2-dimensional part
of the potential energy surfaces in the ground state and the 2-resonance.
Finally we compare the SCF approach on gas-phase N and CO, to
higher accuracy methods. Excitation energies are approximated with accuracy
close to that of time-dependent density functional theory, and we see very good
agreement in the minimum shift of the potential energy surfaces in the excited
state compared to the ground state.Comment: 11 pages, 7 figure
The local electronic structure of alpha-Li3N
New theoretical and experimental investigation of the occupied and unoccupied
local electronic density of states (DOS) are reported for alpha-Li3N. Band
structure and density functional theory calculations confirm the absence of
covalent bonding character. However, real-space full-multiple-scattering
(RSFMS) calculations of the occupied local DOS finds less extreme nominal
valences than have previously been proposed. Nonresonant inelastic x-ray
scattering (NRIXS), RSFMS calculations, and calculations based on the
Bethe-Salpeter equation are used to characterize the unoccupied electronic
final states local to both the Li and N sites. There is good agreement between
experiment and theory. Throughout the Li 1s near-edge region, both experiment
and theory find strong similarities in the s- and p-type components of the
unoccupied local final density of states projected onto an orbital angular
momentum basis (l-DOS). An unexpected, significant correspondence exists
between the near-edge spectra for the Li 1s and N 1s initial states. We argue
that both spectra are sampling essentially the same final density of states due
to the combination of long core-hole lifetimes, long photoelectron lifetimes,
and the fact that orbital angular momentum is the same for all relevant initial
states. Such considerations may be generically applicable for low atomic number
compounds.Comment: 34 pages, 7 figures, 1 tabl
Connected component identification and cluster update on GPU
Cluster identification tasks occur in a multitude of contexts in physics and
engineering such as, for instance, cluster algorithms for simulating spin
models, percolation simulations, segmentation problems in image processing, or
network analysis. While it has been shown that graphics processing units (GPUs)
can result in speedups of two to three orders of magnitude as compared to
serial codes on CPUs for the case of local and thus naturally parallelized
problems such as single-spin flip update simulations of spin models, the
situation is considerably more complicated for the non-local problem of cluster
or connected component identification. I discuss the suitability of different
approaches of parallelization of cluster labeling and cluster update algorithms
for calculations on GPU and compare to the performance of serial
implementations.Comment: 15 pages, 14 figures, one table, submitted to PR
Nurses’ knowledge of heart failure self-management education principles
Heart failure is considered as a chronic disease and the management of such condition is complex and challenging. Nurses play a significant role in managing heart failure by enhancing self-care practices among patients. This paper aims to evaluate evidence from the literature regarding nurses level of knowledge about the educational principles in heart failure. The nine selected studies included a total number of 1181 patients. These studies were conducted in the USA and Europe from 2002 until 2019.the uniqueness of those selected studies that all the authors use the same instrument titled “nurses knowledge of heart failure education principles”. The results revealed that there was an inconsistency in the level of knowledge among nurses in hospital-based, ambulatory, primary care or home care settings. More randomized studies are needed to solve this discrepancy. The level of knowledge ranged from (60.4-79.85%). Six topics have been identified as areas of weakness in which education is needed. Educating nurses in different settings is the gold stander to raise their level of knowledge which in turn will be in a better position to provide a high level of education for patients in order to alleviate their suffering, improve the quality of life and reduce the frequent hospitalization
Compensation of hemispheric albedo asymmetries by shifts of the ITCZ and tropical clouds
Despite a substantial hemispheric asymmetry in clear-sky albedo, observations of Earth's radiation budget reveal that the two hemispheres have the same all-sky albedo. Here, aquaplanet simulations with the atmosphere general circulation model ECHAM6 coupled to a slab ocean are performed to study to what extent and by which mechanisms clouds compensate hemispheric asymmetries in clear-sky albedo. Clouds adapt to compensate the imposed asymmetries because the intertropical convergence zone (ITCZ) shifts into the dark surface hemisphere. The strength of this tropical compensation mechanism is linked to the magnitude of the ITCZ shift. In some cases the ITCZ shift is so strong as to overcompensate the hemispheric asymmetry in clear-sky albedo, yielding a range of climates for which the hemisphere with lower clear-sky albedo has a higher all-sky albedo. The ITCZ shift is sensitive to the convection scheme and the depth of the slab ocean. Cloud-radiative feedbacks explain part of the sensitivity to the convection scheme as they amplify the ITCZ shift in the Tiedtke (TTT) scheme but have a neutral effect in the Nordeng (TNT) scheme. A shallower slab ocean depth, and thereby reduced thermal inertia of the underlying surface and increased seasonal cycle, stabilizes the ITCZ against annual-mean shifts. The results lend support to the idea that the climate system adjusts so as to minimize hemispheric albedo asymmetries, although there is no indication that the hemispheres must have exactly the same albedo. © 2014 American Meteorological Society
Copper flows in buildings, infrastructure and mobiles: a dynamic model and its application to Switzerland
During the last century, the consumption of materials for human needs increased by several orders of magnitude, even for non-renewable materials such as metals. Some data on annual consumption (input) and recycling/waste (output) can often be found in the federal statistics, but a clear picture of the main flows is missing. A dynamic material flow model is developed for the example of copper in Switzerland in order to simulate the relevant copper flows and stocks over the last 150years. The model is calibrated using data from statistical and published sources as well as from interviews and measurements. A simulation of the current state (2000) is compared with data from other studies. The results show that Swiss consumption and losses are both high, at a level of about 8 and 2kg/(capyear), respectively, or about three times higher than the world average. The model gives an understanding of the flows and stocks and their interdependencies as a function of time. This is crucial for materials whose consumption dynamics are characterised by long lifetimes and hence for relating the current output to the input of the whole past. The model allows a comprehensive discussion of possible measures to reduce resource use and losses to the environment. While increasing the recycling reduces losses to landfill, only copper substitution can reduce the different losses to the environment, although with a time delay of the order of a lifetim
Surface-enhanced optical third-harmonic generation in Ag island films
Surface-enhanced optical third-harmonic generation (THG) is observed in
silver island films. The THG intensity from Ag nanoparticles is enhanced by
more than two orders of magnitude with respect to the THG intensity from a
smooth and homogeneous silver surface. This enhancement is attributed to local
plasmon excitation and resonance of the local field at the third-harmonic
wavelength. The diffuse and depolarized component of the enhanced THG is
associated with the third-order hyper-Rayleigh scattering in a 2-D random array
of silver nanoparticles.Comment: 4 pages, 2 figure
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