10,397 research outputs found
Insertion loss measuring apparatus having transformer means connected across a pair of bolometers Patent
High impedance alternating current sensing transformer device between two bolometers for measuring insertion loss of test componen
Pinning control of spatiotemporal chaos
Linear control theory is used to develop an improved localized control scheme for spatially extended chaotic systems, which is applied to a coupled map lattice as an example. The optimal arrangement of the control sites is shown to depend on the symmetry properties of the system, while their minimal density depends on the strength of noise in the system. The method is shown to work in any region of parameter space and requires a significantly smaller number of controllers compared to the method proposed earlier by Hu and Qu [Phys. Rev. Lett. 72, 68 (1994)]. A nonlinear generalization of the method for a 1D lattice is also presented
Do columnar defects produce bulk pinning?
From magneto-optical imaging performed on heavy-ion irradiated YBaCuO single
crystals, it is found that at fields and temperatures where strong single
vortex pinning by individual irradiation-induced amorphous columnar defects is
to be expected, vortex motion is limited by the nucleation of vortex kinks at
the specimen surface rather than by half-loop nucleation in the bulk. In the
material bulk, vortex motion occurs through (easy) kink sliding. Depinning in
the bulk determines the screening current only at fields comparable to or
larger than the matching field, at which the majority of moving vortices is not
trapped by an ion track.Comment: 5 pages, 5 figures, submitted to Physical Review Letter
Magnetic, electronic and vibrational properties of metal and fluorinated metal phthalocyanines
The magnetic and electronic properties of metal phthalocyanines (MPc) and
fluorinated metal phthalocyanines (FMPc) are studied by means of spin
density functional theory (SDFT). Several metals (M) such as Ca, all first
d-row transition metals and Ag are investigated. By considering different open
shell transition metals it is possible to tune the electronic properties of
MPc, in particular the electronic molecular gap and total magnetic moment.
Besides assigning the structural and electronic properties of MPc and
FMPc, the vibrational modes analysis of the ScPc\textendash ZnPc series
have been studied and correlated to experimental measurements when available.Comment: 28 pages (preprint style), several figure
Aspect-Based Sentiment Analysis Using a Two-Step Neural Network Architecture
The World Wide Web holds a wealth of information in the form of unstructured
texts such as customer reviews for products, events and more. By extracting and
analyzing the expressed opinions in customer reviews in a fine-grained way,
valuable opportunities and insights for customers and businesses can be gained.
We propose a neural network based system to address the task of Aspect-Based
Sentiment Analysis to compete in Task 2 of the ESWC-2016 Challenge on Semantic
Sentiment Analysis. Our proposed architecture divides the task in two subtasks:
aspect term extraction and aspect-specific sentiment extraction. This approach
is flexible in that it allows to address each subtask independently. As a first
step, a recurrent neural network is used to extract aspects from a text by
framing the problem as a sequence labeling task. In a second step, a recurrent
network processes each extracted aspect with respect to its context and
predicts a sentiment label. The system uses pretrained semantic word embedding
features which we experimentally enhance with semantic knowledge extracted from
WordNet. Further features extracted from SenticNet prove to be beneficial for
the extraction of sentiment labels. As the best performing system in its
category, our proposed system proves to be an effective approach for the
Aspect-Based Sentiment Analysis
Solid state television camera system Patent
Solid state television camera system consisting of monolithic semiconductor mosaic sensor and molecular digital readout system
Stochastic gain in population dynamics
We introduce an extension of the usual replicator dynamics to adaptive
learning rates. We show that a population with a dynamic learning rate can gain
an increased average payoff in transient phases and can also exploit external
noise, leading the system away from the Nash equilibrium, in a reasonance-like
fashion. The payoff versus noise curve resembles the signal to noise ratio
curve in stochastic resonance. Seen in this broad context, we introduce another
mechanism that exploits fluctuations in order to improve properties of the
system. Such a mechanism could be of particular interest in economic systems.Comment: accepted for publication in Phys. Rev. Let
Galaxies at z=4 and the Formation of Population II
We report the discovery of four high-redshift objects (3.3 < z < 4) observed
behind the rich cluster CL0939+4713 (Abell 851). One object (DG 433) has a
redshift of z=3.3453; the other three objects have redshifts of z\approx 4: A0
at z=3.9819, DG 353 and P1/P2 at z=3.9822. It is possible that all four objects
are being lensed in some way by the cluster, DG 433 being weakly sheared, A0
being strongly sheared, and DG 353 and P1/P2 being an image pair of a common
source object; detailed modelling of the cluster potential will be necessary to
confirm this hypothesis. The weakness of common stellar wind features like N V
and especially C IV in the spectra of these objects argues for sub-solar
metallicities, at least as low as the SMC. DG 353 and DG 433, which have
ground-based colors, are moderately dusty [E_{int}(B-V) < 0.15], similar to
other z>3 galaxies. Star formation rates range from 2.5 (7.8) h^{-2} to 22.
(78.) h^{-2} M_{\odot}/yr, for q_0=0.5 (0.05), depending on assumptions about
gravitational lensing and extinction, also typical of other z>3 galaxies. These
objects are tenatively identified as the low-metallicity proto-spheroid clumps
that will merge to form the Population II components of today's spheroids.Comment: 16 pages, including 2 PostScript figures. Needs aaspp4.sty
(included). Accepted for publication in the Astrophysical Journa
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