82,799 research outputs found
Parameter estimation and model testing for Markov processes via conditional characteristic functions
Markov processes are used in a wide range of disciplines, including finance.
The transition densities of these processes are often unknown. However, the
conditional characteristic functions are more likely to be available,
especially for L\'{e}vy-driven processes. We propose an empirical likelihood
approach, for both parameter estimation and model specification testing, based
on the conditional characteristic function for processes with either continuous
or discontinuous sample paths. Theoretical properties of the empirical
likelihood estimator for parameters and a smoothed empirical likelihood ratio
test for a parametric specification of the process are provided. Simulations
and empirical case studies are carried out to confirm the effectiveness of the
proposed estimator and test.Comment: Published in at http://dx.doi.org/10.3150/11-BEJ400 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
Localization of Macroscopic Object Induced by the Factorization of Internal Adiabatic Motion
To account for the phenomenon of quantum decoherence of a macroscopic object,
such as the localization and disappearance of interference, we invoke the
adiabatic quantum entanglement between its collective states(such as that of
the center-of-mass (C.M)) and its inner states based on our recent
investigation. Under the adiabatic limit that motion of C.M dose not excite the
transition of inner states, it is shown that the wave function of the
macroscopic object can be written as an entangled state with correlation
between adiabatic inner states and quasi-classical motion configurations of the
C.M. Since the adiabatic inner states are factorized with respect to each parts
composing the macroscopic object, this adiabatic separation can induce the
quantum decoherence. This observation thus provides us with a possible solution
to the Schroedinger cat paradoxComment: Revtex4,23 pages,1figur
On the Relation of Hard X-ray Peak Flux and Outburst Waiting Time in the Black Hole Transient GX 339-4
Aims. In this work we re-investigated the empirical relation between the hard
X-ray peak flux and the outburst waiting time found previously in the black
hole transient GX 339-4. We tested the relation using the observed hard X-ray
peak flux of the 2007 outburst of GX 339-4, clarified issues about faint
flares, and estimated the lower limit of hard X-ray peak flux for the next
outburst. Methods. We included Swift/BAT data obtained in the past four years.
Together with the CGRO/BATSE and RXTE/HEXTE light curves, the observations used
in this work cover a period of 18 years. Results. The observation of the 2007
outburst confirms the empirical relation discovered before. This strengthens
the apparent link between the mass in the accretion disk and the peak
luminosity of the brightest hard state that the black hole transient can reach.
We also show that faint flares with peak fluxes smaller than about 0.12 crab do
not affect the empirical relation. We predict that the hard X-ray peak flux of
the next outburst should be larger than 0.65 crab, which will make it at least
the second brightest in the hard X-ray since 1991.Comment: 4 pages, 3 figures, accepted by A&
XOR multiplexing technique for nanocomputers
In emerging nanotechnologies, due to the manufacturing process, a significant percentage of components may be faulty. In order to make systems based on unreliable nano-scale components reliable, it is necessary to design fault-tolerant architectures. This paper presents a novel fault-tolerant technique for nanocomputers, namely the XOR multiplexing technique. This hardware redundancy technique is based on a numerous duplication of faulty components. We analyze the error distributions of the XOR multiplexing unit and the error distributions of multiple stages of the XOR multiplexing system, then compare them to the NAND multiplexing unit and the NAND multiplexing multiple stages system, respectively. The simulation results show that XOR multiplexing is more reliable than NAND multiplexing. Bifurcation theory is used to analyze the fault-tolerant ability of the system and the results show that XOR multiplexing technique has a high fault-tolerant ability. Similarly to the NAND multiplexing technique, this fault-tolerant technique is a potentially effective fault tolerant technique for future nanoelectronics
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