23 research outputs found
End-to-End Available Bandwidth Estimation Tools, An Experimental Comparison
Abstract. The available bandwidth of a network path impacts the per-formance of many applications, such as VoIP calls, video streaming and P2P content distribution systems. Several tools for bandwidth estimation have been proposed in the last years but there is still uncertainty in their accuracy and efficiency under different network conditions. Although a number of experimental evaluations have been carried out in order to compare some of these methods, a comprehensive evaluation of all the existing active tools for available bandwidth estimation is still missing. This article introduces an empirical comparison of most of the active esti-mation tools actually implemented and freely available nowadays. Abing, ASSOLO, DietTopp, IGI, pathChirp, Pathload, PTR, Spruce and Yaz have been compared in a controlled environment and in presence of dif-ferent sources of cross-traffic. The performance of each tool has been investigated in terms of accuracy, time and traffic injected into the net-work to perform an estimation.
Extracting kinetic freeze-out temperature and radial flow velocity from an improved Tsallis distribution
We analyze the transverse momentum () spectra of identified particles
(, , , and ) produced in gold-gold (Au-Au) and
lead-lead (Pb-Pb) collisions over a (center-of-mass energy per
nucleon pair) range from 14.5 GeV [one of the Relativistic Heavy Ion Collider
(RHIC) energies] to 2.76 TeV [one of the Large Hadron Collider (LHC) energies].
For the spectra with a narrow range, an improved Tsallis distribution
which is in fact the Tsallis distribution with radial flow is used. For the
spectra with a wide range, a superposition of the improved Tsallis
distribution and an inverse power-law is used. Both the extracted kinetic
freeze-out temperature () and radial flow velocity () increase
with the increase of , which indicates a higher excitation and
larger expansion of the interesting system at the LHC. Both the values of
and in central collisions are slightly larger than those in
peripheral collisions, and they are independent of isospin and slightly
dependent on mass.Comment: We have corrected the pseudorapidity ranges of the data quoted in
this paper. The PHENIX data should be in the pseudorapidity range
, but not the rapidity range ; and the ALICE data
should be in for high transverse momentum region and
for low transverse momentum region, but not only . These do not
affect the results of the publicatio
Zinc oxide films prepared by sol–gel spin coating technique
Zinc oxide (ZnO) thin films and micro- and nanostructures are very promising candidates for novel applications in emerging thin-film transistors, solar cells, sensors and optoelectronic devices. In this paper, a low-cost sol-gel spin coating technique was used to fabricate ZnO films on glass substrates. The sol-gel fabrication process of the ZnO films is described. The influence of precursor concentration on the material properties of the ZnO films was investigated. Atomic force microscopy and X-ray diffractometry were employed to examine the structural properties of the ZnO films. The optical properties of the ZnO films were characterized with ultraviolet-visible spectroscopy. The experimental results reveal that the precursor concentration in the sol-gel spin coating process exerts a strong influence on the properties of the ZnO films. The effects of the precursor concentration are discussed.
Document Type: Articl