World Science

Journal Information
ISSN / EISSN : 2413-1032 / 2414-6404
Published by: RS Global Sp. z O.O. (10.31435)
Total articles ≅ 742

Latest articles in this journal

Albert Khachik Sahakyan
Published: 25 August 2021
List coloring is a vertex coloring of a graph where each vertex can be restricted to a list of allowed colors. For a given graph G and a set L(v) of colors for every vertex v, a list coloring is a function that maps every vertex v to a color in the list L(v) such that no two adjacent vertices receive the same color. It was first studied in the 1970s in independent papers by Vizing and by Erdős, Rubin, and Taylor. A block graph is a type of undirected graph in which every biconnected component (block) is a clique. A complete bipartite graph is a bipartite graph with partitions V 1, V 2 such that for every two vertices v_1∈V_1 and v_2∈V_2 there is an edge (v 1, v 2). If |V_1 |=n and |V_2 |=m it is denoted by K_(n,m). In this paper we provide a polynomial algorithm for finding a list coloring of block graphs and prove that the problem of finding a list coloring of K_(n,m) is NP-complete even if for each vertex v the length of the list is not greater than 3 (|L(v)|≤3).
Napoleon Meskhia
Published: 23 August 2021
The analysis of the causes of postoperative complications was carried out, as well as of the failures and errors or the same omissions in postoperative management. The total number of cases was 177 (5%) among more than 3500 patients, being operated on various clinical and anatomical forms of craniocerebral trauma.In 63.8% (in 113 patients), worsening of condition was associated with the postoperative hemorrhage, which in 54% of cases was shell- recurrent. In 36.6% of observations (in 64 patients), deteriorated states of the brain swelling or edema were associated with an increase of cerebral edema.The main causes of the postoperative volume hemorrhages were the inadequacy of homeostasis and fluctuations in blood pressure during the first hours and days after surgery, with a tendency of significant increase of that latter. Diagnostic errors were the result of underestimation or incorrect evaluation of neurological symptoms and clinical signs of repeated volumetric hemorrhages.Late diagnosis of postoperative complications resulted in a lethal outcome in 79 (44.6%) cases among 177 patients with the complications in the postoperative process. Neurological and clinical signs and their combinations characteristic for postoperative volumetric hemorrhages are given in the article, as well as are offered the ways of their prevention.
Serbenuyk A. V., Kaminskiy V. V.
Published: 20 August 2021
The article presents an analysis of literature data and the results of our own retrospective studies of the characteristics of the menstrual cycle in female combatants who have undergone concussion. Clinical and anamnestic factors have been identified that negatively affect the menstrual function of women of reproductive age, who received contusions during hostilities. The relationship between the state of mental health of women and menstrual irregularities has been established. Aim: to identify and evaluate changes in the menstrual function of women - veterans of reproductive age. Also, to establish the relationship between menstrual irregularities in women - veterans of reproductive age who have undergone contusion, and the state of their somatic and mental health.Materials and method: The research was conducted at the Department of Obstetrics, Gynecology and Reproductology of the National University of Health of Ukraine named after P.L. Shupika. To achieve this goal, a comprehensive clinical and laboratory examination was performed in 567 women of reproductive age (main group and comparison group) who participated in hostilities and suffered contusions, the average age of the subjects was 27.08 ± 4.23 years.The period of stay in the combat zone is 29.34 ± 9.21 months, the time from the moment of receiving a mild traumatic brain injury (contusion) is 18.8 ± 9.2 months. Group I - 399 fertile women who suffered contusions during the fighting with PKS. Group II - 168 women of childbearing age who suffered contusions during hostilities without PKS (mean age 32.21 ± 7.32 years).Results: The results of the studies revealed statistically significant deviations in the characteristics of the menstrual cycle of women who participated in hostilities who were injured with PKS, compared with women without PKS. It has been proven that women-viskovosluzhvits more often develop menstrual irregularities, namely a decrease or increase in the number, lengthening or shortening of the menstrual cycle by 7 days. Taking into account the revealed menstrual irregularities in the women under study, it can be argued that the detected changes are due to the influence of both craniocerebral trauma and stress factors associated with military service. This justifies the need to develop a program for monitoring and supporting the reproductive health of women-viyskovoservices, as well as medical and psychological rehabilitation of veterans, aimed at their full adaptation to a peaceful life.
Hulii D. Ya., Boichuk O. H.
Published: 17 August 2021
Ovarian tumors may be found in women of any age and the period of pregnancy is no exception. Besides, this period is related to some specific adnexal tumors. A systematic use of ultrasonography in the first trimester of pregnancy has led to a wider detection of symptomless adnexal tumors. The majority of adnexal tumors diagnosed during pregnancy are accidental findings of routine examinations of pregnancy. According to various estimations, the incidence of adnexal neoplasms during pregnancy makes up from 0.19 to 8.8 %. Most of cases are diagnosed in the first trimester and their incidence gradually decreases as the period of pregnancy grows: Trimester 1 – from 21.4 to 75.7 %; Trimester 2 – from 10.9 to 44.4 %; Trimester 3 – from 4 to 22.2 %; after labor – from 0 to 7.1 %. Most of adnexal tumors during pregnancy are benign and physiological and often regress spontaneously. Depending on their size and location, ovarian tumors may be related to an adverse obstetrical result caused by mechanical influence. They increase the risk of abortion (from 0 to 6 %), preterm labor (from 5.8 to 10.4 %) and mechanical impediment to labor. In view of the above mentioned considerations, one of the objectives of our research is to make a retrospective analysis of perinatal peculiarities in women with benign ovarian neoplasms.
В. О. Костюк, О. М. Слободян
Published: 14 August 2021
Using modern anatomical methods, 57 preparations of human fetuses 4-10 months and 7 newborns were studied in order to create models of distances of supra-, suborbital and chin openings between themselves and to standard landmarks in fetuses and newborns taking into account their morphometric parameters. The model of the distance from the supraorbital foramen to bregma (Y1): Y1 = β0 + 0.092 x parietal-heel length of the fetus, where β0 :: 2,783, if the age period = 4 months; 3,106 = 5 months; -0.662 = 6 months; 4,728 = 7 months; 2,676 = 8 months; 0.402 = 9 months; -1,727 = 10 months; 9,094 = newborns; model of the distance between the supra- and suborbital foramina (Y2): Y2 = β0 + 0.011 x parietal-heel length of the fetus, where β0 :: 8,147, if the age period = 4 months; 9.086 = 5 months; 10,260 = 6 months; 12,020 = 7 months; 12,129 = 8 months; 15,164 = 9 months; 17,429 = 10 months; 18,808 = newborns; model of the distance between the orbital and chin openings (Y3): Y3 = β0 + 0.002 x parietal-heel length of the fetus, where β0 :: 8.987, if the age period = 4 months; 9,134 = 5 months; 9,892 = 6 months; 12,250 = 7 months; 11,636 = 8 months; 16,755 = 9 months; 17,877 = 10 months; 18,054 = newborns; model of the distance between the chin holes and the lower edge of the mandible (Y4): Y4 = β0 + 0.008 x parietalheel length of the fetus, where β0 :: 0.268, if the age period = 4 months; 0.178 = 5 months; 0.020 = 6 months; -0.152 = 7 months; 0.020 = 8 months; - 0.115 = 9 months; -0.079 = 10 months; -0.039 = newborns; model of the distance between the orbital foramina (Y5): Y5 = β0 + 0.030 x parietal-heel length of the fetus, where β0 :: 5,762, if the age period = 4 months; 5,895 = 5 months; 11,227 = 6 months; 13,793 = 7 months; 11,691 = 8 months; 11,173 = 9 months; 12,633 = 10 months; 14,494 = newborns; model of the distance between the orbital foramina (Y6): Y6 = β0 + 0.008 x parietal-heel length of the fetus, where β0 :: 9,272, if the age period = 4 months; 11,081 = 5 months; 13,467 = 6 months; 16,854 = 7 months; 15,912 = 8 months; 17,653 = 9 months; 22,635 = 10 months; 23,447 = newborns; model of the distance between the chin holes (Y7): Y7 = β0 - 0.014 x parietal-heel length of the fetus, where β0 :: 12,959, if the age period = 4 months; 15,282 = 5 months; 18,117 = 6 months; 23,178 = 7 months; 23,175 = 8 months; 30,496 = 9 months; 32,227 = 10 months; 33,272 = newborns.
Salimov Vagif Hasan Oglu
Published: 13 August 2021
This article is devoted to the problem of decision making under linguistic uncertainty. The effective method for modelling linguistic uncertainty is the fuzzy set theory. There are several types of fuzzy number types proposed by L. Zadeh: fuzzy type-1, fuzzy type-2, Z-numbers. Chen proposed concept of generalized fuzzy numbers. Generalized trapezoidal fuzzy numbers (GTFN) one of effective approach which can be used for modeling linguistic uncertainty. GFTN very convenient model which allow take in account second order uncertainty. GFTN are formalized and major operations are described as practical problem is considered group decision making for supplier selection. In this case the criteria assessments are expressed by experts in linguistic form. Group decision making model is presented as 2 step aggregation procedure, in first step is aggregated value of alternative by expert, in second step by criteria. Numerical example with four criteria and three alternatives are presented and solved.
, Gennady Shvachych, Valentyna Chorna, Nataliiya Voroshylova
Published: 11 August 2021
The research aims at covering the mathematical modeling issues of multidimensional applied problems of ecology based on the application of a modular computing complex. The problem of modeling air pollution processes is solved by mathematical models that adequately describe fundamental processes. That reveals issues such as a detailed analysis of the atmosphere of the city or industrial area, short-term forecast of air quality in the region, assessment of long term air purification programs, optimal emission management, transboundary transfer, etc. At the same time, the formulation and methods of solving problems of environmental dynamics identification are considered, which essence is to estimate the input parameters based on the factual information about the modeled system known from the experiment. In these studies, the multidimensional equation of harmful impurities transfer was reduced to a sequence of schemes involving unknown values in a single direction, alternately in the longitudinal, transverse and vertical.The implicit schemes lead to systems of algebraic linear equations with a three-diagonal structure. Thus, the methodological basis of the difference splitting schemes provides the economic and sustainable implementation of numerical models by the scalar runs method. That approach focuses on the fact that the greatest effect of a parallel processor is achieved when it is used to perform matrix computations of linear algebra.In order to analyze the feasibility of mathematical models, a package of applications was developed to compute the transfer of harmful impurities. A solution to several applied problems for the identification of the environmental dynamics is given.
Salimov Vagif Hasan Oglu
Published: 10 August 2021
The article is devoted to the problem of multi-criteria decision-making. Methods for solving this problem can be divided into two large groups:methods using the aggregation of all alternatives according to all criteria and the solution of the resulting single-criterion problem. The second group isassociated with the procedure of pairwise comparisons and stepwise aggregation. The first group includes methods: weighted average sum,product and their various modifications, the second group includes - AHP, ELECTRE, TOPSIS, PROMETHEE, ELECTRE. For many problemsassessment of the criteria implemented by experts and presented in linguistic form. The effective approach for dealing with linguistic information is fuzzyset theory proposed by L. Zadeh. In this paper is proposed fuzzy ELECTRE method. This method is presented in details. As application problem is usedthe equipment selection problem The issues of practical implementation of this method are discussed in details. The results of the solution test problem at all stages are presented.
Tarasenko D. O., Kriuchkova L. P.
Published: 30 July 2021
The processes of information support of situational management of infocommunication networks in the conditions of influence of external disturbances are considered in the work. The expediency of using the mathematical apparatus of information theory for the analysis of processes of control of parameters of infocommunication networks is substantiated. It is shown that periodic multiple sequential control of the parameters of the infocommunication network provides determination of the state of the network under the influence of external interference and the probability of its transition to a new state in the near future. The entropy of the controlled process changes with changing quantization step and multiple successive measurements. It is noted that in the case of periodic multiple consecutive control, the object is constantly in transition in terms of information. The entropy value of an object can be considered determined only for some short periods of time between measurements or when information about the object is not received. An important condition for improving the quality of control is to reduce and completely eliminate delays in the information process.
Polishchuk V.,
Published: 28 July 2021
The development of road transport, both economically and socially, is of great importance for humanity. But along with the tremendous benefits andunlimited potential of road transport, there are many problems, particularly with its operation in human settlements, particularly in cities. Theseproblems are related to the oversaturation of the road network of cities with road transport, which leads to a decrease in speed, congestion, increased traveltime. Ensuring the required capacity of the site is the main indicator of creating conditions for the efficient functioning of the transport system of cities.Each section has its own planning features that allow the car to move at an acceptable speed and at the same time not create any situations that could lead to the formation of congestion.It is known that the lower the speed, the greater the time spent. Speed is one of the most important indicators of traffic flow. Any reduction in the speed of traffic flows compared to the permitted leads to economic losses. And if we consider the reduction of speed, taking into account the stop in motion (delay), it leads to much greater economic losses.
Back to Top Top