37,409 research outputs found
Ontology mapping neural network: An approach to learning and inferring correspondences among ontologies
An ontology mapping neural network (OMNN) is proposed in order to learn and infer correspondences among ontologies. It extends the Identical Elements Neural Network (IENN)'s ability to represent and map complex relationships. The learning dynamics of simultaneous (interlaced) training of similar tasks interact at the shared connections of the networks. The output of one network in response to a stimulus to another network can be interpreted as an analogical mapping. In a similar fashion, the networks can be explicitly trained to map specific items in one domain to specific items in another domain. Representation layer helps the network learn relationship mapping with direct training method. OMNN is applied to several OAEI benchmark test cases to test its performance on ontology mapping. Results show that OMNN approach is competitive to the top performing systems that participated in OAEI 2009
Ferromagnetism in 2p Light Element-Doped II-oxide and III-nitride Semiconductors
II-oxide and III-nitride semiconductors doped by nonmagnetic 2p light
elements are investigated as potential dilute magnetic semiconductors (DMS).
Based on our first-principle calculations, nitrogen doped ZnO, carbon doped
ZnO, and carbon doped AlN are predicted to be ferromagnetic. The ferromagnetism
of such DMS materials can be attributed to a p-d exchange-like p-p coupling
interaction which is derived from the similar symmetry and wave function
between the impurity (p-like t_2) and valence (p) states. We also propose a
co-doping mechanism, using beryllium and nitrogen as dopants in ZnO, to enhance
the ferromagnetic coupling and to increase the solubility and activity
Color-flavor locked strangelets in a quark mass density-dependent model
The color-flavor locked (CFL) phase of strangelets is investigated in a quark
mass density-dependent model. Parameters are determined by stability arguments.
It is concluded that three solutions to the system equations can be found,
corresponding, respectively, to positively charged, negatively charged, and
nearly neutral CFL strangelets. The charge to baryon number of the positively
charged strangelets is smaller than the previous result, while the charge of
the negatively charged strangelets is nearly proportional in magnitude to the
cubic-root of the baryon number. However, the positively charged strangelets
are more stable compared to the other two solutions.Comment: 11 pages,7 figures, Accepted for publication in Int. J. Mod. Phys.
Equilibrium Times for the Multicanonical Method
This work measures the time to equilibrium for the multicanonical method on
the 2D-Ising system by using a new criterion, proposed here, to find the time
to equilibrium, teq, of any sampling procedure based on a Markov process. Our
new procedure gives the same results that the usual one, based on the
magnetization, for the canonical Metropolis sampling on a 2D-Ising model at
several temperatures. For the multicanonical method we found a power-law
relationship with the system size, L, of teq=0.27(15) L^2.80(13), and with the
number of energy levels to explore, kE, of teq=0.7(13) kE^1.40(11), in perfect
agreement with the result just above. In addition, some kind of critical
slowing down was observed around the critical energy. Our new procedure is
completely general, and can be applied to any sampling method based on a Markov
process.Comment: 7 pages, 5 eps figures, to be published in Int. J. Mod. Phys.
Joint Semantic and Latent Attribute Modelling for Cross-Class Transfer Learning
This work is partially supported by grants from the
National Natural Science Foundation of China under
contract No. 61390515, No. U1611461, and No.
61425025, and the National Basic Research Program
of China under Grant No. 2015CB351806
Effect of nonstationarities on detrended fluctuation analysis
Detrended fluctuation analysis (DFA) is a scaling analysis method used to
quantify long-range power-law correlations in signals. Many physical and
biological signals are ``noisy'', heterogeneous and exhibit different types of
nonstationarities, which can affect the correlation properties of these
signals. We systematically study the effects of three types of
nonstationarities often encountered in real data. Specifically, we consider
nonstationary sequences formed in three ways: (i) stitching together segments
of data obtained from discontinuous experimental recordings, or removing some
noisy and unreliable parts from continuous recordings and stitching together
the remaining parts -- a ``cutting'' procedure commonly used in preparing data
prior to signal analysis; (ii) adding to a signal with known correlations a
tunable concentration of random outliers or spikes with different amplitude,
and (iii) generating a signal comprised of segments with different properties
-- e.g. different standard deviations or different correlation exponents. We
compare the difference between the scaling results obtained for stationary
correlated signals and correlated signals with these three types of
nonstationarities.Comment: 17 pages, 10 figures, corrected some typos, added one referenc
Dispersion, damping, and intensity of spin excitations in the single-layer (Bi,Pb)(Sr,La)CuO cuprate superconductor family
Using Cu- edge resonant inelastic x-ray scattering (RIXS) we measured
the dispersion and damping of spin excitations (magnons and paramagnons) in the
high- superconductor (Bi,Pb)(Sr,La)CuO
(Bi2201), for a large doping range across the phase diagram (). Selected measurements with full polarization analysis
unambiguously demonstrate the spin-flip character of these excitations, even in
the overdoped sample. We find that the undamped frequencies increase slightly
with doping for all accessible momenta, while the damping grows rapidly, faster
in the (0,0)(0.5,0.5) nodal direction than in the
(0,0)(0.5,0) antinodal direction. We compare the experimental
results to numerically exact determinant quantum Monte Carlo (DQMC)
calculations that provide the spin dynamical structure factor
of the three-band Hubbard model. The theory reproduces
well the momentum and doping dependence of the dispersions and spectral weights
of magnetic excitations. These results provide compelling evidence that
paramagnons, although increasingly damped, persist across the superconducting
dome of the cuprate phase diagram; this implies that long range
antiferromagnetic correlations are quickly washed away, while short range
magnetic interactions are little affected by doping.Comment: 11 pages, 9 figure
- …