Lesya Ukrainka Eastern European National University

vnu.edu.ua/
Luts'k, Ukraine

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Stepanyuk S.,Lesya Ukrainka Eastern European National University
Perspective Technologies and Methods in MEMS Design, MEMSTECH'2010 - Proceedings of the 6th International Conference | Year: 2010

This paper provides an introduction to the field of artificial neural network by brief reviewing some neural net models that can be used for pattern recognition. There are made a few open problems in this area of research.


Odintsova A.,Ivan Franko National University of Lviv | Fishchuk O.,Lesya Ukrainka Eastern European National University
Acta Agrobotanica | Year: 2017

The general morphology and micromorphology of the flower in Polygonatum multiflorum, Maianthemum bifolium, and Convallaria majalis were studied using light microscopy methods. Among the studied species, P. multiflorum and C. majalis have syntepalous and trimerous flowers, and in M. bifolium flowers are the most reduced: they are dimerous, pentacyclic, and with free tepals. Only in P. multiflorum stamens are considerably adnate to the floral tube. The gynoecium of P. multiflorum consists of synascidiate, hemisymplicate, and asymplicate zones. In the gynoecium of M. bifolium and C. majalis, synascidiate, symplicate, and asymplicate vertical zones were revealed. In P. multiflorum and M. bifolium, the style is composed of postgenitally connated carpels, while in C. majalis the style is formed by congenitally fused carpels (symplicate gynoecium zone). A common pattern of the venation of the floral parts was revealed in all the species. The external flower morphology and the gynoecium inner structure are different in all three species, providing adaptations for the pollination mode. Attractive elements observed in the flower of P. multiflorum are the long septal nectary in the ovary and epidermal trichomes on the inner perigonium surface and on the filaments. In M. bifolium, a rudimentary external septal nectary was observed for the first time. No nectaries or other morphologically distinct secretory structures were found in the C. majalis flower, allowing considering the C. majalis flowers as pollen flowers. © The Author(s) 2017.


Stepanyuk S.,Lesya Ukrainka Eastern European National University
2011 11th International Conference - The Experience of Designing and Application of CAD Systems in Microelectronics, CADSM 2011 | Year: 2011

The goal of this paper is the consideration of the solving of visual attention on the based of winner-take-all neural networks. Selective tuning and Mozer model of visual attention are considered here. Also limitations, advances and open problems are shown. © 2011 Lviv Polytechnic National.


Kormosh Z.,Lesya Ukrainka Eastern European National University | Savchuk T.,Lesya Ukrainka Eastern European National University
Materials Science and Engineering C | Year: 2012

The characteristics, performance and application of novel triiodide potentiometric sensor based on ion-pair of Rhodamine B triiodide as a membrane carrier are described. The electrode has a linear dynamic range between 1 × 10 - 6 and 1 × 10 - 1 M, with a Nernstian slope of 68 ± 1 mV pC - 1 and detection limit of 3.9 × 10 - 7 M. Fast and stable response, good reproducibility, long-term stability, very good selectivity over a large number of common organic and inorganic anions, applicability over a pH range of 2-10 are demonstrated. The proposed sensor has been applied for potentiometric determination of some iodine species. © 2012 Elsevier B.V.


Daszkiewicz M.,Institute of Low Temperature And Structure Research | Marchuk O.V.,Lesya Ukrainka Eastern European National University | Gulay L.D.,Lesya Ukrainka Eastern European National University | Kaczorowski D.,Institute of Low Temperature And Structure Research
Journal of Alloys and Compounds | Year: 2012

The crystal structures of several novel quaternary compounds R 2PbSi 2S 8 (R = Y, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho), R 2PbSi 2Se 8 (R = La, Ce, Pr, Nd, Sm, Gd) and R 2PbGe 2S 8 (R = Ce, Pr) have been determined by means of single-crystal and powder X-ray diffraction. All these phases crystallize with hexagonal unit cells of the La 2PbSi 2S 8 type (space group R-3c, Pearson symbol hR78), in which rare-earth and lead atoms are statistically distributed over centers of bi-capped trigonal prisms made by chalcogen atoms. The magnetic properties of R 2PbSi 2S 8 and R 2PbSi 2Se 8 with R = La, Ce, Pr and Sm have been studied in wide temperature and magnetic field ranges. The La-based materials are weakly diamagnetic, whereas all the other compounds exhibit strongly temperature dependent paramagnetic behaviour due to the presence of well localized magnetic moments of trivalent rare-earth ions. © 2011 Elsevier B.V. All rights reserved.


Mikhailyuk V.A.,Lesya Ukrainka Eastern European National University
Cybernetics and Systems Analysis | Year: 2016

Using gap-introducing and gap-preserving reductions, it is shown that there is no polynomial-time approximation scheme (PTAS) for the multiple reoptimization of the problem of calculating the chromatic number of a graph with a given exponentially growing set of optimal solutions when inserting an arbitrary vertex with no more than two edges incident to it and also when eliminating an arbitrary vertex together with all the edges incident to it. The same result holds for ordinary reoptimization. © 2016, Springer Science+Business Media New York.


Lishchuk N.V.,Lesya Ukrainka Eastern European National University
Journal of Automation and Information Sciences | Year: 2015

It is shown that for the set covering problems (which differ in one position of the constraint matrix) there are not κ-probabilistic polynomial procedures for the analysis of the stability (Κ ∈ {ZPP, RP}) for Κ ≠ NP.


Gulay L.D.,Lesya Ukrainka Eastern European National University | Daszkiewicz M.,Institute of Low Temperature And Structure Research | Shemet V.Y.,Lutsk National Technical University
Journal of Solid State Chemistry | Year: 2012

The crystal structures of ternary compounds TbCu 3S 3, Dy 1.06Cu 2.84S 3 (space group R3), Ho 0.67Cu 2S 2 (space group P3m1), ErCu 3S 3 (space group P31c), Yb 0.80Cu 1.60S 2, Lu 0.67Cu 2S 2, TbCuTe 2, DyCuTe 2, Tm 1.07Cu 0.78Te 2, LuCuTe 2 (space group P3m1), Gd 0.75Cu 1.74Te 2 (space group P31m) were determined by means of X-ray single crystal diffraction. The S(Te) atoms are stacked in a close packed arrangement with the layers in the sequence AB. The R atoms are distributed over octahedral interstices whereas Cu atoms are located in tetrahedral interstices. Disorder of R and Cu atoms in studied chalcogenides is found. Crystal structure comparison showed that TbCuTe 2 and DyCuTe 2 crystallize as superstructure 2a×2a× 2c to CaAl 2Si 2 structure type, whereas Gd 0.75Cu 1.74Te 2, ErCu 3S 3 and TbCu 3S 3 (Dy 1.06Cu 2.84S 3) have superstructure √3a×√3a×nc with n=1, 2, 3. © 2011 Elsevier Inc.


Strok O.M.,Lesya Ukrainka Eastern European National University | Daszkiewicz M.,Institute of Low Temperature And Structure Research | Gulay L.D.,Lesya Ukrainka Eastern European National University | Kaczorowski D.,Institute of Low Temperature And Structure Research
Journal of Alloys and Compounds | Year: 2010

The crystal structures of novel quaternary compounds Sm3CuGeS7 and Sm3CuGeSe7 were determined by means of X-ray single crystal diffraction. They are of the La3CuSiS7 structure type, space group P63, Pearson symbol hP24. The refined lattice parameters are a = 10.0106(7) Å, s{cyrillic} = 5.7702(6) Å for Sm3CuGeS7, and a = 10.4091(9) Å, s{cyrillic} = 6.0382(6) Å for Sm3CuGeSe7. Magnetic measurements revealed that both compounds are paramagnetic down to 1.72 K. © 2009 Elsevier B.V. All rights reserved.


Daszkiewicz M.,Institute of Low Temperature And Structure Research | Gulay L.D.,Lesya Ukrainka Eastern European National University
Materials Research Bulletin | Year: 2012

The compounds with the general formula Ln 3MTX 7 (space group P6 3) (Ln - rare-earth element, M - monovalent element (Cu, Ag), T - Si, Ge, Sn and X - S, Se) are interesting owing to the possible application in the field of ionic conductivity. In the crystal structure the face-sharing [Ag(S) 6] triangular antiprisms form the channels where the Ag + ion can migrate along the crystallographic c axis. High-pressure X-ray diffraction shows that Ag + ion moves towards the central-point of [Ag(S) 6] when pressure is risen. As a consequence, the coordination number of Ag + changes from CN = 3 to CN = 6 at ∼3 GPa. The La 3Ag 0.82SnS 7 has stiff structure; zero-pressure bulk modulus is B 0 = 61.74 GPa and the pressure derivative is B' 0=4.02. © 2011 Elsevier Ltd. All rights reserved.

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