406 research outputs found
Neural Distributed Autoassociative Memories: A Survey
Introduction. Neural network models of autoassociative, distributed memory
allow storage and retrieval of many items (vectors) where the number of stored
items can exceed the vector dimension (the number of neurons in the network).
This opens the possibility of a sublinear time search (in the number of stored
items) for approximate nearest neighbors among vectors of high dimension. The
purpose of this paper is to review models of autoassociative, distributed
memory that can be naturally implemented by neural networks (mainly with local
learning rules and iterative dynamics based on information locally available to
neurons). Scope. The survey is focused mainly on the networks of Hopfield,
Willshaw and Potts, that have connections between pairs of neurons and operate
on sparse binary vectors. We discuss not only autoassociative memory, but also
the generalization properties of these networks. We also consider neural
networks with higher-order connections and networks with a bipartite graph
structure for non-binary data with linear constraints. Conclusions. In
conclusion we discuss the relations to similarity search, advantages and
drawbacks of these techniques, and topics for further research. An interesting
and still not completely resolved question is whether neural autoassociative
memories can search for approximate nearest neighbors faster than other index
structures for similarity search, in particular for the case of very high
dimensional vectors.Comment: 31 page
The web-based information system for small and medium enterprises of Tomsk region
This paper presents the web enabled automated information data support system of small and medium-sized enterprises of Tomsk region. We define the purpose and application field of the system. In addition, we build a generic architecture and find system functions
Temperature dependence of self-trapped exciton luminescence in nanostructured hafnia powder
The intrinsic optical properties and peculiarities of the energy structure of
hafnium dioxide largely determine the prospects for applying the latter in new
generation devices of optoelectronics and nanoelectronics. In this work, we
have studied the diffuse reflectance spectra at room temperature for a
nominally pure nanostructured powder with a monoclinic crystal
structure and, as well its photoluminescence in the temperature range of 40 -
300 K. We have also estimated the bandgap under the assumption made for
indirect (5.31 eV) and direct (5.61 eV) allowed transitions. We have detected
emission with a 4.2 eV maximum at T < 200 K and conducted an analysis of the
experimental dependencies to evaluate the activation energies of thermal
quenching (140 meV) and enhancement (3 meV) processes. Accounting for both the
temperature behavior of the spectral characteristics and the estimation of the
Huang-Rhys factor S >> 1 has shown that radiative decay of self-trapped
excitons forms the mechanism of the indicated emission. In this case, the
localization is mainly due to the interaction of holes with active vibrational
modes of oxygen atoms in non-equivalent ( and ) crystal
positions. Thorough study of the discussed excitonic effects can advance
development of hafnia-based structures with a controlled optical response.Comment: 21 pages, 7 figures, 2 tables, 56 references. Keywords: hafnium
dioxide, self-trapped exciton, F-center, thermal quenching of luminescence,
luminescence enhacement, Huang-Rhys factor, effective phonon energy, bandgap
widt
Nonlocal density functionals and the linear response of the homogeneous electron gas
The known and usable truly nonlocal functionals for exchange-correlation
energy of the inhomogeneous electron gas are the ADA (average density
approximation) and the WDA (weighted density approximation). ADA, by design,
yields the correct linear response function of the uniform electron gas. WDA is
constructed so that it is exact in the limit of one-electron systems. We derive
an expression for the linear response of the uniform gas in the WDA, and
calculate it for several flavors of WDA. We then compare the results with the
Monte-Carlo data on the exchange-correlation local field correction, and
identify the weak points of conventional WDA in the homogeneous limit. We
suggest how the WDA can be modified to improve the response function. The
resulting approximation is a good one in both opposite limits, and should be
useful for practical nonlocal density functional calculations.Comment: 4 pages, two eps figures embedde
INTERACTION OF PERSPECTIVE ANTIDEPRESSANT WITH NOOTROPIC PROPERTIES 2-METHYL-3-PHENYLAMINOMETHYLQUINOLIN-4-ONE WITH CNS STIMULANTS AND DEPRESSANTS
Purpose. To research possible interactions of 2-methyl-3-phenylaminomethylquinolin-4-one (3-AMQ) with CNS stimulants and depressants.Materials and methods. The interaction of the said substance with strychnine and thiosemicarbazide was studied on the seizure models, with caffeine - in the open field test, with CNS depressants (sodium thiopental, ethanol) - measuring duration of the anesthetic sleep.Results. The trend of attenuation of strychnine and thiosemicarbazide convulsive action was revealed on seizure models for 3-AMQ. In the open field test 3-AMQ leveled the anxiogenic effects of caffeine that was reflected in the exploratory activity increase. The trend of elongation of narcosis induction time (up to 18%) and reduction of narcosis duration (up to 17%) was found in the model using thiopental-induced anesthesia. In the ethanol-induced narcosis 3-AMQ reduced the duration of animals’ anesthetic sleep by 19.2% (p<0.05).Summary. The absence of pro-convulsive properties and potentiating interactions with barbiturates was proved for 3-AMQ. Beneficial modulating influence on effects of caffeine was revealed. The alcoprotective activity of 3-AMQ was proved
Classification of hyperbolic Dynkin diagrams, root lengths and Weyl group orbits
We give a criterion for a Dynkin diagram, equivalently a generalized Cartan
matrix, to be symmetrizable. This criterion is easily checked on the Dynkin
diagram. We obtain a simple proof that the maximal rank of a Dynkin diagram of
compact hyperbolic type is 5, while the maximal rank of a symmetrizable Dynkin
diagram of compact hyperbolic type is 4. Building on earlier classification
results of Kac, Kobayashi-Morita, Li and Sa\c{c}lio\~{g}lu, we present the 238
hyperbolic Dynkin diagrams in ranks 3-10, 142 of which are symmetrizable. For
each symmetrizable hyperbolic generalized Cartan matrix, we give a
symmetrization and hence the distinct lengths of real roots in the
corresponding root system. For each such hyperbolic root system we determine
the disjoint orbits of the action of the Weyl group on real roots. It follows
that the maximal number of disjoint Weyl group orbits on real roots in a
hyperbolic root system is 4.Comment: J. Phys. A: Math. Theor (to appear
On The 100th Anniversary Of The Founder Of The Odessa Scientific School Of Economic Thought A. K. Pokrytan
The partnership between the Odessa National University of Economics and "D. A. Tsenov” Academy of Economics is an example of a successful model for adding value in the field of scientific research. With its annual scientific conferences, the Odessa National University of Economics has provided dozens of scientists from the Svishtov Academy and other foreign researchers with the opportunity to publish their papers abroad. Prof. Mihail Zveryakov himself is a Doctor Honoris Causa (Zastrahovatel.com, 2010) of D. A. Tsenov Academy and a prominent co-author in collaborative research publications indexed in SCOPUS Q1/WoS (Zahariev, et al., 2020). The paper commemorates and pays due respect to Prof. Anatoly Karpovich Pokrytan - one of the most prominent scientists in the field of economics whose centenary provided his scientific followers with the opportunity to reflect on his scientific legacy. The 100th anniversary of the establishment of the Odessa National Economic University in Ukraine (founded under the name Odessa Institute of National Economy) on 16 May 1921 is another evidence for our Ukrainian partner’s tenacity during the decades of intense socio-economic and ideological changes of the 20th and the 21st century
Morphometric analysis of pancytokeratin-negative neoplastic damages of the lymphatic nodes of the neck.
Patients with a diagnosis of cancer with an unknown primary localization (CUPL) are mostly referred to the category of cancer cohort with the clinical manifestation of lymph nodes enlargement. Cases of CUPL occupy 3-5% of all neoplasia of any localization, and only 20% of them have prognostically better chances as compared to other 80%. Materials and methods. The retrospective study 41 observations of the neoplastic lymph nodes in the neck without other clinical manifestations of primary tumor localization during was performed August 2016 - July 2017. The average age of patients was 47.68±16.41 years (median 46). The aim of the study was to analyze the complex of morphological, morphometric and immunohistochemical characteristics of Cytokeratin, Ran negative phenotypes of neoplastic lesions of lymph nodes of the neck for the improvement of diagnostic algorithms. Results. The authors have adjusted the objective parameters of nuclei of tumor cells (area, perimeter, coefficient of "roundness"), in comparison with the size of ordinary lymphocytes, the dependence of the size of the nuclei on morphological characteristics and the immunophenotype of the neoplastic damage of the lymph nodes of the neck has been analyzed
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