71,431 research outputs found
Self Interference of Single Electrodynamic Particle in Double Slit
It is by the long established fact in experiment and theory that
electromagnetic waves, here as one component of an IED particle, passing a
double slit will undergo self inference each, producing at a detector plane
fringed intensities. The wave generating point charge of a zero rest mass, as
the other component of the particle, is maintained a constant energy and speed
by a repeated radiation reabsorption/reemission scheme, and in turn steered in
direction in its linear motion by the reflected radiation field, and will
thereby travel to the detector along (one of) the optical path(s) of the waves
leading to a bright interference fringe. We elucidate the process formally
based on first principles solutions for the IED particle and known principles
for wave-matter interaction.Comment: Presentation at The 6th Int. Symp. Quantum Theory and Symmetries,
Univ. Kent, 2009
Corrections to scaling in the dynamic approach to the phase transition with quenched disorder
With dynamic Monte Carlo simulations, we investigate the continuous phase
transition in the three-dimensional three-state random-bond Potts model. We
propose a useful technique to deal with the strong corrections to the dynamic
scaling form. The critical point, static exponents and , and
dynamic exponent are accurately determined. Particularly, the results
support that the exponent satisfies the lower bound .Comment: 10 pages, 6 figures, 2 table
Dynamic effect of overhangs and islands at the depinning transition in two-dimensional magnets
With the Monte Carlo methods, we systematically investigate the short-time
dynamics of domain-wall motion in the two-dimensional random-field Ising model
with a driving field ?DRFIM?. We accurately determine the depinning transition
field and critical exponents. Through two different definitions of the domain
interface, we examine the dynamics of overhangs and islands. At the depinning
transition, the dynamic effect of overhangs and islands reaches maximum. We
argue that this should be an important mechanism leading the DRFIM model to a
different universality class from the Edwards-Wilkinson equation with quenched
disorderComment: 9 pages, 6 figure
Determination of electron-nucleus collision geometry with forward neutrons
There are a large number of physics programs one can explore in
electron-nucleus collisions at a future electron-ion collider. Collision
geometry is very important in these studies, while the measurement for an
event-by-event geometric control is rarely discussed in the prior deep
inelastic scattering experiments off a nucleus. This paper seeks to provide
some detailed studies on the potential of tagging collision geometries through
forward neutron multiplicity measurements with a zero degree calorimeter. This
type of geometry handle, if achieved, can be extremely beneficial in
constraining nuclear effects for the electron-nucleus program at an
electron-ion collider
Stochastic Tools for Network Intrusion Detection
With the rapid development of Internet and the sharp increase of network
crime, network security has become very important and received a lot of
attention. We model security issues as stochastic systems. This allows us to
find weaknesses in existing security systems and propose new solutions.
Exploring the vulnerabilities of existing security tools can prevent
cyber-attacks from taking advantages of the system weaknesses. We propose a
hybrid network security scheme including intrusion detection systems (IDSs) and
honeypots scattered throughout the network. This combines the advantages of two
security technologies. A honeypot is an activity-based network security system,
which could be the logical supplement of the passive detection policies used by
IDSs. This integration forces us to balance security performance versus cost by
scheduling device activities for the proposed system. By formulating the
scheduling problem as a decentralized partially observable Markov decision
process (DEC-POMDP), decisions are made in a distributed manner at each device
without requiring centralized control. The partially observable Markov decision
process (POMDP) is a useful choice for controlling stochastic systems. As a
combination of two Markov models, POMDPs combine the strength of hidden Markov
Model (HMM) (capturing dynamics that depend on unobserved states) and that of
Markov decision process (MDP) (taking the decision aspect into account).
Decision making under uncertainty is used in many parts of business and
science.We use here for security tools.We adopt a high-quality approximation
solution for finite-space POMDPs with the average cost criterion, and their
extension to DEC-POMDPs. We show how this tool could be used to design a
network security framework.Comment: Accepted by International Symposium on Sensor Networks, Systems and
Security (2017
Second coefficient of viscosity in air
Acoustic attenuation measurements in air were analyzed in order to estimate the second coefficient of viscosity. Data over a temperature range of 11 C to 50 C and at relative humidities between 6 percent and 91 percent were used. This analysis showed that the second coefficient of viscosity varied between 1900 and 20,000 times larger than the dynamic or first coefficient of viscosity over the temperature and humidity range of the data. In addition, the data showed that the molecular relaxation effects, which are responsible for the magnitude of the second coefficient of viscosity, place severe limits on the use of time-independent, thermodynamic equations of state. Compressible flows containing large streamwise velocity gradients, like shock waves, which cause significant changes in particle properties to occur during time intervals shorter than hundredths of seconds, must be modeled using dynamic equations of state. The dynamic model approach is described briefly
Environmental Effects on Real-Space and Redshift-Space Galaxy Clustering
Galaxy formation inside dark matter halos, as well as the halo formation
itself, can be affected by large-scale environments. Evaluating the imprints of
environmental effects on galaxy clustering is crucial for precise cosmological
constraints with data from galaxy redshift surveys. We investigate such an
environmental impact on both real-space and redshift-space galaxy clustering
statistics using a semi-analytic model derived from the Millennium Simulation.
We compare clustering statistics from original SAM galaxy samples and shuffled
ones with environmental influence on galaxy properties eliminated. Among the
luminosity-threshold samples examined, the one with the lowest threshold
luminosity (~0.2L_*) is affected by environmental effects the most, which has a
~10% decrease in the real-space two-point correlation function (2PCF) after
shuffling. By decomposing the 2PCF into five different components based on the
source of pairs, we show that the change in the 2PCF can be explained by the
age and richness dependence of halo clustering. The 2PCFs in redshift space are
found to change in a similar manner after shuffling. If the environmental
effects are neglected, halo occupation distribution modeling of the real-space
and redshift-space clustering may have a less than 6.5% systematic uncertainty
in constraining beta from the most affected SAM sample and have substantially
smaller uncertainties from the other, more luminous samples. We argue that the
effect could be even smaller in reality. In the Appendix, we present a method
to decompose the 2PCF, which can be applied to measure the two-point
auto-correlation functions of galaxy sub-samples in a volume-limited galaxy
sample and their two-point cross-correlation functions in a single run
utilizing only one random catalog.Comment: 13 pages, 6 figures, Accepted by AP
- …