3,483 research outputs found
A general approximation of quantum graph vertex couplings by scaled Schroedinger operators on thin branched manifolds
We demonstrate that any self-adjoint coupling in a quantum graph vertex can
be approximated by a family of magnetic Schroedinger operators on a tubular
network built over the graph. If such a manifold has a boundary, Neumann
conditions are imposed at it. The procedure involves a local change of graph
topology in the vicinity of the vertex; the approximation scheme constructed on
the graph is subsequently `lifted' to the manifold. For the corresponding
operator a norm-resolvent convergence is proved, with the natural
identification map, as the tube diameters tend to zero.Comment: 19 pages, one figure; introduction amended and some references added,
to appear in CM
Characterization of a novel reassortant H5N6 highly pathogenic avian influenza virus clade 2.3.4.4 in Korea, 2017
Nuclear Mass Dependence of Chaotic Dynamics in Ginocchio Model
The chaotic dynamics in nuclear collective motion is studied in the framework
of a schematic shell model which has only monopole and quadrupole degrees of
freedom. The model is shown to reproduce the experimentally observed global
trend toward less chaotic motion in heavier nuclei. The relation between
current approach and the earlier studies with bosonic models is discussed.Comment: 11 Page REVTeX file, 2 postscript figures, uuencode
Above-Room-Temperature Ferromagnetism in GaSb/Mn Digital Alloys
Digital alloys of GaSb/Mn have been fabricated by molecular beam epitaxy.
Transmission electron micrographs showed good crystal quality with individual
Mn-containing layers well resolved; no evidence of 3D MnSb precipitates was
seen in as-grown samples. All samples studied exhibited ferromagnetism with
temperature dependent hysteresis loops in the magnetization accompanied by
metallic p-type conductivity with a strong anomalous Hall effect (AHE) up to
400 K (limited by the experimental setup). The anomalous Hall effect shows
hysteresis loops at low temperatures and above room temperature very similar to
those seen in the magnetization. The strong AHE with hysteresis indicates that
the holes interact with the Mn spins above room temperature. All samples are
metallic, which is important for spintronics applications.
* To whom correspondence should be addressed. E-mail: [email protected]
Spectral properties on a circle with a singularity
We investigate the spectral and symmetry properties of a quantum particle
moving on a circle with a pointlike singularity (or point interaction). We find
that, within the U(2) family of the quantum mechanically allowed distinct
singularities, a U(1) equivalence (of duality-type) exists, and accordingly the
space of distinct spectra is U(1) x [SU(2)/U(1)], topologically a filled torus.
We explore the relationship of special subfamilies of the U(2) family to
corresponding symmetries, and identify the singularities that admit an N = 2
supersymmetry. Subfamilies that are distinguished in the spectral properties or
the WKB exactness are also pointed out. The spectral and symmetry properties
are also studied in the context of the circle with two singularities, which
provides a useful scheme to discuss the symmetry properties on a general basis.Comment: TeX, 26 pages. v2: one reference added and two update
Facial Expression Restoration Based on Improved Graph Convolutional Networks
Facial expression analysis in the wild is challenging when the facial image
is with low resolution or partial occlusion. Considering the correlations among
different facial local regions under different facial expressions, this paper
proposes a novel facial expression restoration method based on generative
adversarial network by integrating an improved graph convolutional network
(IGCN) and region relation modeling block (RRMB). Unlike conventional graph
convolutional networks taking vectors as input features, IGCN can use tensors
of face patches as inputs. It is better to retain the structure information of
face patches. The proposed RRMB is designed to address facial generative tasks
including inpainting and super-resolution with facial action units detection,
which aims to restore facial expression as the ground-truth. Extensive
experiments conducted on BP4D and DISFA benchmarks demonstrate the
effectiveness of our proposed method through quantitative and qualitative
evaluations.Comment: Accepted by MMM202
Secure searching of biomarkers through hybrid homomorphic encryption scheme
Background: As genome sequencing technology develops rapidly, there has lately been an increasing need to keep genomic data secure even when stored in the cloud and still used for research. We are interested in designing a protocol for the secure outsourcing matching problem on encrypted data. Method: We propose an efficient method to securely search a matching position with the query data and extract some information at the position. After decryption, only a small amount of comparisons with the query information should be performed in plaintext state. We apply this method to find a set of biomarkers in encrypted genomes. The important feature of our method is to encode a genomic database as a single element of polynomial ring. Result: Since our method requires a single homomorphic multiplication of hybrid scheme for query computation, it has the advantage over the previous methods in parameter size, computation complexity, and communication cost. In particular, the extraction procedure not only prevents leakage of database information that has not been queried by user but also reduces the communication cost by half. We evaluate the performance of our method and verify that the computation on large-scale personal data can be securely and practically outsourced to a cloud environment during data analysis. It takes about 3.9 s to search-and-extract the reference and alternate sequences at the queried position in a database of size 4M. Conclusion: Our solution for finding a set of biomarkers in DNA sequences shows the progress of cryptographic techniques in terms of their capability can support real-world genome data analysis in a cloud environment
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