72,106 research outputs found
A novel approach for the assessment of morphological evolution based on observed water levels in tide-dominated estuaries
Assessing the impacts of both natural (e.g., tidal forcing from the ocean) and human-induced changes (e.g., dredging for navigation, land reclamation) on estuarine morphology is particularly important for the protection and management of the estuarine environment. In this study, a novel analytical approach is proposed for the assessment of estuarine morphological evolution in terms of tidally averaged depth on the basis of the observed water levels along the estuary. The key lies in deriving a relationship between wave celerity and tidal damping or amplification. For given observed water levels at two gauging stations, it is possible to have a first estimation of both wave celerity (distance divided by tidal travelling time) and tidal damping or amplification rate (tidal range difference divided by distance), which can then be used to predict the morphological changes via an inverse analytical model for tidal hydrodynamics. The proposed method is applied to the Lingdingyang Bay of the Pearl River Estuary, located on the southern coast of China, to analyse the historical development of the tidal hydrodynamics and morphological evolution. The analytical results show surprisingly good correspondence with observed water depth and volume in this system. The merit of the proposed method is that it provides a simple approach for understanding the decadal evolution of the estuarine morphology through the use of observed water levels, which are usually available and can be easily measured.National Key R&D of China (Grant No.
2016YFC0402601), National Natural Science Foundation of China (Grant No. 51979296, 51709287,
41706088, 41476073), Fundamental Research Funds for the Central Universities (No.18lgpy29)
and from the Water Resource Science and Technology Innovation Program of Guangdong Province (Grant
No. 2016-20, 2016-21). The work of the second author was supported by FCT research contracts
IF/00661/2014/CP1234.info:eu-repo/semantics/submittedVersio
Integrable impurities in Hubbard chain with the open boundary condition
The Kondo problem of two impurities in 1D strongly correlated electron system
within the framework of the open boundary Hubbard chain is solved and the
impurities, coupled to the ends of the electron system, are introduced by their
scattering matrices with electrons so that the boundary matrices satisfy the
reflecting integrability condition. The finite size correction of the ground
state energy is obtained due to the impurities. Exact expressions for the low
temperature specific heat contributed by the charge and spin parts of the
magnetic impurities are derived. The Pauli susceptibility and the Kondo
temperature are given explicitly. The Kondo temperature is inversely
proportional to the density of electrons.Comment: 6 pages, Revtex, To appear in Europhysics Letter
Group-level Emotion Recognition using Transfer Learning from Face Identification
In this paper, we describe our algorithmic approach, which was used for
submissions in the fifth Emotion Recognition in the Wild (EmotiW 2017)
group-level emotion recognition sub-challenge. We extracted feature vectors of
detected faces using the Convolutional Neural Network trained for face
identification task, rather than traditional pre-training on emotion
recognition problems. In the final pipeline an ensemble of Random Forest
classifiers was learned to predict emotion score using available training set.
In case when the faces have not been detected, one member of our ensemble
extracts features from the whole image. During our experimental study, the
proposed approach showed the lowest error rate when compared to other explored
techniques. In particular, we achieved 75.4% accuracy on the validation data,
which is 20% higher than the handcrafted feature-based baseline. The source
code using Keras framework is publicly available.Comment: 5 pages, 3 figures, accepted for publication at ICMI17 (EmotiW Grand
Challenge
Electrical Characterization of PbZr0.4Ti0.6O3 Capacitors
We have conducted a careful study of current-voltage (I-V) characteristics in
fully integrated commercial PbZr0.4Ti0.6O3 thin film capacitors with Pt bottom
and Ir/IrO2 top electrodes. Highly reproducible steady state I-V were obtained
at various temperatures over two decades in voltage from current-time data and
analyzed in terms of several common transport models including space charge
limited conduction, Schottky thermionic emission under full and partial
depletion and Poole-Frenkel conduction, showing that the later is the most
plausible leakage mechanism in these high quality films. In addition,
ferroelectric hysteresis loops and capacitance-voltage data were obtained over
a large range of temperatures and discussed in terms of a modified
Landau-Ginzburg-Devonshire theory accounting for space charge effects.Comment: 17 pages, 7 figure
Lensing effect on the relative orientation between the Cosmic Microwave Background ellipticities and the distant galaxies
The low redshift structures of the Universe act as lenses in a similar way on
the Cosmic Microwave Background light and on the distant galaxies (say at
redshift about unity). As a consequence, the CMB temperature distortions are
expected to be statistically correlated with the galaxy shear, exhibiting a
non-uniform distribution of the relative angle between the CMB and the galactic
ellipticities. Investigating this effect we find that its amplitude is as high
as a 10% excess of alignement between CMB and the galactic ellipticities
relative to the uniform distribution. The relatively high signal-to-noise ratio
we found should makes possible a detection with the planned CMB data sets,
provided that a galaxy survey follow up can be done on a sufficiently large
area. It would provide a complementary bias-independent constraint on the
cosmological parameters.Comment: 7 pages, 3 figures; uses emulateapj.sty; submitted to Ap
Alternative proof for the localization of Sinai's walk
We give an alternative proof of the localization of Sinai's random walk in
random environment under weaker hypothesis than the ones used by Sinai.
Moreover we give estimates that are stronger than the one of Sinai on the
localization neighborhood and on the probability for the random walk to stay
inside this neighborhood
Electromagnetic manipulation for anti-Zeno effect in an engineered quantum tunneling process
We investigate the quantum Zeno and anti-Zeno effects for the irreversible
quantum tunneling from a quantum dot to a ring array of quantum dots. By
modeling the total system with the Anderson-Fano-Lee model, it is found that
the transition from the quantum Zeno effect to quantum anti-Zeno effect can
happen as the magnetic flux and the gate voltage were adjusted.Comment: 6 pages, 5 figure
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