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 $HfO_2$ 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 $E_g$ 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 ($O_{3f}$ and $O_{4f}$) 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

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

Immunological substantiation of complex therapy in patients with mild HPV-associated cervical intraepithelial neoplasia

Introduction. As is known, the development of invasive cervical cancer is preceded by cervical intraepithelial neoplasia of varying severity, which is a pathological process in which cells with varying degrees of atypia and impaired differentiation appear in the thickness of the stratified squamous epithelium of the cervix.Objective. To study the  effect of  complex therapy in  patients with mild HPV-associated cervical intraepithelial neoplasia on the dynamics of local cytokine status and autoimmunity parameters.Materials and methods. The study included 86 patients aged 35 to 40 years with morphologically verified mild cervical intraepithelial neoplasia. The main group consisted of 52 patients who, along with radio wave destruction of the cervix, were prescribed an immunostimulating drug with antiviral activity “Groprinosin-Richter” 1000 mg 3 times a day for 10 days 10–14 days before destruction and similar 2 courses after 10–14 days after it. The comparison group included 34 patients who underwent only radio wave destruction of the cervix.Results. An analysis of the outcomes of low-grade squamous intraepithelial lesions after 6 months showed that in the main group, CIN I regression was observed in 92.3% of patients, persistence – in 7.7% of cases, while in the comparison group, CIN I regression was noted in 73,5% of cases, persistence – in 26.5% of patients.Conclusions. Conducting complex therapy, including radio wave destruction and the use of a drug with immunostimulating and antiviral activity “Groprinosin-Richter” in  patients with low-grade HPV-associated cervical intraepithelial neoplasia, leads to the elimination of the initial imbalance of cytokines and normalization of autoantibody levels, helping to reduce the likelihood of HPV persistence and CIN progression to invasive cervical cancer uterus