1,000 research outputs found
Blockchain: The emerging technology of digital trust
© 2019 Elsevier Ltd Trust in individual relationships with blockchain has become an increasingly prominent issue. This study introduces a key heuristic used to assess trust in blockchain by analyzing how privacy and security concerns about blockchains have an impact on the user\u27s attitude and behavior. It proposes a blockchain user model by integrating security and privacy as primary influencing factors of trust and behavioral intent. The results from a user experience model of blockchain users confirm that the model explains user experience and predicts behavioral intent of blockchain. The results establish users’ cognitive role in embedding privacy and security in blockchain. The research contributes to the ongoing research by clarifying the role and dimension of trust in relation to security and privacy in blockchains and provides heuristic implications for academia and industry
Experimental and numerical investigation on cross flow in the PMR200 core
Papers presented to the 11th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 20-23 July 2015.The Prismatic Modular Reactor (PMR) is one of the major Very High Temperature Reactor (VHTR) concepts, which consists of hexagonal prismatic fuel blocks and reflector blocks made of nuclear grade graphite. However, the shape of graphite blocks could be easily changed by neutron damage during the reactor operation and the shape change can make the gaps between the blocks inducing bypass flow. Two types of gap shape should be considered. The vertical gap and horizontal gap are called bypass gap and cross gap, respectively. The cross gap complicates flow field in reactor core by connecting coolant channel and bypass gap and it could lead to loss of effective coolant flow in fuel blocks. In this paper, cross flow experimental facility was constructed to investigate the cross flow phenomena in the core of the VHTR and the experiment was carried out under varying flow rates and gap sizes. The results of the experiments were compared with CFD (Computational Fluid Dynamics) analysis results. In order to apply the CFD code to the cross flow phenomena, the prediction capability of the CFD code was verified. Good agreement between experimental results and CFD predictions was observed and the characteristics of the cross flow was discussed in detail.This work was supported by a Basic Atomic Energy Research Institute (BAERI) grant funded by the Korean government Ministry of Education and Science Technology (MEST) (NRF-2010-0018759)am201
Hydrodynamical analysis of hadronic spectra in the 130 GeV/nucleon Au+Au collisions
We study one-particle spectra and a two-particle correlation function in the
130 GeV/nucleon Au+Au collisions at RHIC by making use of a hydrodynamical
model. We calculate the one-particle hadronic spectra and present the first
analysis of Bose-Einstein correlation functions based on the numerical solution
of the hydrodynamical equations which takes both longitudinal and transverse
expansion into account appropriately. The hydrodynamical model provides
excellent agreement with the experimental data in the pseudorapidity and the
transverse momentum spectra of charged hadrons, the rapidity dependence of
anti-proton to proton ratio, and almost consistent result for the pion
Bose-Einstein correlation functions. Our numerical solution with simple
freeze-out picture suggests the formation of the quark-gluon plasma with large
volume and low net-baryon density.Comment: 7 pages, 8 figures, REVTeX4. Numerical results and figures are
correcte
Proton strangeness form factors in (4,1) clustering configurations
We reexamine a recent result within a nonrelativistic constituent quark model
(NRCQM) which maintains that the uuds\bar s component in the proton has its
uuds subsystem in P state, with its \bar s in S state (configuration I). When
the result are corrected, contrary to the previous result, we find that all the
empirical signs of the form factors data can be described by the lowest-lying
uuds\bar s configuration with \bar s in P state that has its uuds subsystem in
state (configuration II). Further, it is also found that the removal of the
center-of-mass (CM) motion of the clusters will enhance the contributions of
the transition current considerably. We also show that a reasonable description
of the existing form factors data can be obtained with a very small probability
P_{s\bar s}=0.025% for the uuds\bar s component. We further see that the
agreement of our prediction with the data for G_A^s at low-q^2 region can be
markedly improved by a small admixture of configuration I. It is also found
that by not removing CM motion, P_{s\bar s} would be overestimated by about a
factor of four in the case when transition dominates over direct currents.
Then, we also study the consequence of a recent estimate reached from analyzing
the existing data on quark distributions that P_{s\bar s} lies between 2.4-2.9%
which would lead to a large size for the five-quark (5q) system, as well as a
small bump in both G^s_E+\eta G^s_M and G^s_E in the region of q^2 =< 0.1
GeV^2.Comment: Prepared for The Fifth Asia-Pacific Conference on Few-Body Problems
in Physics 2011 in Seoul, South Korea, 22-26 August 201
Comparison of space-time evolutions of hot/dense matter in =17 and 130 GeV relativistic heavy ion collisions based on a hydrodynamical model
Based on a hydrodynamical model, we compare 130 GeV/ Au+Au collisions at
RHIC and 17 GeV/ Pb+Pb collisions at SPS. The model well reproduces the
single-particle distributions of both RHIC and SPS.
The numerical solution indicates that huge amount of collision energy in RHIC
is mainly used to produce a large extent of hot fluid rather than to make a
high temperature matter; longitudinal extent of the hot fluid in RHIC is much
larger than that of SPS and initial energy density of the fluid is only 5%
higher than the one in SPS. The solution well describes the HBT radii at SPS
energy but shows some deviations from the ones at RHIC.Comment: 28 pages, 21 figures, REVTeX4, one figure is added and some figures
are replace
Mathematics of Gravitational Lensing: Multiple Imaging and Magnification
The mathematical theory of gravitational lensing has revealed many generic
and global properties. Beginning with multiple imaging, we review
Morse-theoretic image counting formulas and lower bound results, and
complex-algebraic upper bounds in the case of single and multiple lens planes.
We discuss recent advances in the mathematics of stochastic lensing, discussing
a general formula for the global expected number of minimum lensed images as
well as asymptotic formulas for the probability densities of the microlensing
random time delay functions, random lensing maps, and random shear, and an
asymptotic expression for the global expected number of micro-minima. Multiple
imaging in optical geometry and a spacetime setting are treated. We review
global magnification relation results for model-dependent scenarios and cover
recent developments on universal local magnification relations for higher order
caustics.Comment: 25 pages, 4 figures. Invited review submitted for special issue of
General Relativity and Gravitatio
Search for sterile neutrino oscillation using RENO and NEOS data
We present a reactor model independent search for sterile neutrino
oscillation using 2\,509\,days of RENO near detector data and 180 days of NEOS
data. The reactor related systematic uncertainties are significantly suppressed
as both detectors are located at the same reactor complex of Hanbit Nuclear
Power Plant. The search is performed by electron
antineutrino\,() disappearance between six reactors and two
detectors with baselines of 294\,m\,(RENO) and 24\,m\,(NEOS). A spectral
comparison of the NEOS prompt-energy spectrum with a no-oscillation prediction
from the RENO measurement can explore reactor oscillations
to sterile neutrino. Based on the comparison, we obtain a 95\% C.L. excluded
region of \,eV. We also obtain a 68\% C.L. allowed
region with the best fit of \,eV and
=0.080.03 with a p-value of 8.2\%. Comparisons of
obtained reactor antineutrino spectra at reactor sources are made among RENO,
NEOS, and Daya Bay to find a possible spectral variation.Comment: 6 pages, 5 figures: This manuscript has been significantly revised by
the joint reanalysis by RENO and NEOS Collaborations. (In the previous
edition, the RENO collaboration used publicly available NEOS data to evaluate
the expected neutrino spectrum at NEOS.
Measurement of the Proton Spin Structure Function g1p with a Pure Hydrogen Target
A measurement of the proton spin structure function g1p(x,Q^2) in
deep-inelastic scattering is presented. The data were taken with the 27.6 GeV
longitudinally polarised positron beam at HERA incident on a longitudinally
polarised pure hydrogen gas target internal to the storage ring. The kinematic
range is 0.021<x<0.85 and 0.8 GeV^2<Q^2<20 GeV^2. The integral
Int_{0.021}^{0.85} g1p(x)dx evaluated at Q0^2 of 2.5 GeV^2 is
0.122+/-0.003(stat.)+/-0.010(syst.).Comment: 7 pages, 3 figures, 1 table, RevTeX late
A Study of Cosmic Ray Secondaries Induced by the Mir Space Station Using AMS-01
The Alpha Magnetic Spectrometer (AMS-02) is a high energy particle physics
experiment that will study cosmic rays in the to range and will be installed on the International Space Station
(ISS) for at least 3 years. A first version of AMS-02, AMS-01, flew aboard the
space shuttle \emph{Discovery} from June 2 to June 12, 1998, and collected
cosmic ray triggers. Part of the \emph{Mir} space station was within the
AMS-01 field of view during the four day \emph{Mir} docking phase of this
flight. We have reconstructed an image of this part of the \emph{Mir} space
station using secondary and emissions from primary cosmic rays
interacting with \emph{Mir}. This is the first time this reconstruction was
performed in AMS-01, and it is important for understanding potential
backgrounds during the 3 year AMS-02 mission.Comment: To be submitted to NIM B Added material requested by referee. Minor
stylistic and grammer change
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