№ 114(10), December, 2015
Public date: 30.12.2015
Archive of journal: Articles count 111, 292 kb
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MATHEMATICAL THEORY OF RATINGS
01.00.00 Physical-mathematical sciences
Description
When developing management solutions with the aim of joint consideration and comparison of various factors, partial removal of uncertainty is widely used ratings. In the theory of decisionmaking in almost the same sense, we use the terms "composite index" or "integrated indicator". The article is devoted to the mathematical theory of ratings as tools for studying socio-economic systems. We considered, primarily, linear ratings which is a linear function from a single (private) indicators (factors, criteria), constructed using the coefficients of importance (weightiness, importance). The study discusses the factors affecting the magnitude of the ratings. Three groups of causes affect the value of a line ranking: the ways of measurement of individual indicators, the choice of the set of indicators; the values of the coefficients of importance. We considered binary ratings when the rating takes two values. To compare the proposed rankings we use a new indicator of the quality of diagnostics and prognostic power. Significantly, in many managerial situations, significant differences between objects are identified using any rating. According to the fundamental results of stability theory, the same source data should be processed in several ways. Matching findings, obtained using multiple methods, likely reflect the properties of reality. The difference is the result of a subjective selection method. When using the results of the comparison of objects according to several indicators (criteria ratings), including in dynamics, very useful is the selection of the Pareto set. We discuss the examples of the application of the decision theory, expert evaluations and rankings when developing complex technical systems
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INTERCONNECTION LIMIT THEOREMS AND MONTE-CARLO METHOD
01.00.00 Physical-mathematical sciences
Description
The purpose of mathematical statistics is development of methods for the data analysis intended to solve applied problems. Over time, approaches to the development of data analysis methods have changed. A hundred years ago, it was assumed, that the distributions of the data have a certain type, for example, they are normal distributions, and on that assumption they developed a statistical theory. The next stage, in the first place in theoretical studies there are limit theorems. By "small sample" we mean a sample, which can not be applied to conclusions based on the limit theorems. In each statistical problem there is a need to divide the final sample sizes into two classes - those for which you can apply the limit theorems, and those for which you can not do it because of the risk of incorrect conclusions. To solve this problem we often used the Monte Carlo method. More complex problems arise when studying the effect on the properties of statistical procedures for data analysis of various deviations from the original assumptions. To study such impact, we often used the Monte Carlo method as well. The basic (and not solved in a general way) problem of the study of the stability of the findings in the presence of deviations from the parametric families of distributions is the problem of choosing some distributions for using in modeling. We consider some examples of application of the Monte Carlo method, relating to the activities of our research team. We have also formulated basic unsolved problems
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REAL AND NOMINAL SIGNIFICANCE LEVELS IN STATISTICAL HYPOTHESIS TESTING
01.00.00 Physical-mathematical sciences
Description
In the statistical hypothesis testing, critical values often point to a priori fixed (nominal) significance levels. As such, typically researcher uses the values of three numbers 0.01, 0.05, 0.1, to which may be added a few levels: 0.001, 0.005, 0.02, and others. However, for the statistics with discrete distribution functions, which, in particular, include all nonparametric statistical tests, the real significance levels may be different from the nominal, differ at times. Under the real significance level we refer to the highest possible significance level of discrete statistics, not exceeding a given nominal significance level (ie, the transition to the next highest possible value corresponding discrete statistical significance level is greater than a predetermined nominal). In the article, we have discussed the difference between nominal and real significance levels on the example of nonparametric tests for the homogeneity of two independent samples. We have also studied two-sample Wilcoxon test, the criterion of van der Waerden, Smirnov two-sample two-sided test, sign test, runs test (Wolfowitz) and calculated the real significance levels of the criteria for nominal significance level of 0.05. The study of the power of these statistical tests is accomplished by means of Monte Carlo method. The main conclusion: the use of nominal significance levels instead of real significance levels for discrete statistics is inadmissible for small sample sizes
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CYCLONE REGIME MODIFICATIONS IN NORTHERN AND SOUTHERN HEMISPHERE IN CONDITIONS OF CHANGING CLIMATE
01.00.00 Physical-mathematical sciences
Description
The main objective of this article is to solve a problem of a numerical identification of cyclones based on the reanalysis data. The results show that the amount of cyclones is increasing during last 66 years, the number and depth of cyclones are larger in Northern Hemisphere than in Southern, and Northern Hemisphere cyclones become deeper and deeper with time. Cyclonic activity in the Northern Hemisphere mainly is caused by large number of cyclones, in the Southern Hemisphere – by their depth. In the Northern Hemisphere cyclone characteristics change significantly
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THE INVERSE PROBLEM OF OPTIMAL ONESTEP AND MULTI-STEP FILTERING OF MEASUREMENT ERRORS IN THE VECTOR
01.00.00 Physical-mathematical sciences
Description
In practice, we often encounter the problem of determining a system state based on results of various measurements. Measurements are usually accompanied by random errors; therefore, we should not talk about the definition of the system state but its estimation through stochastic processing of measurement results. In the monograph by E. A. Semenchina and M. Z. Laipanova [1] it was investigated for one-step filtering of the measurement errors of the vector of demand in balance model of Leontiev, as well as multistage optimal filtering of measurement errors of the vector of demand. In this article, we have delivered and investigated the inverse problem for the optimal one-step and multi-step filtering of the measurement errors of the vector of demand. For its solution, the authors propose the method of conditional optimization and using given and known disturbance to determine (estimate) the matrix elements for one-step filtering of measurement errors and for multi-stage filtration: for given variables and known disturbance to determine the elements of the matrix. The solution of the inverse problem is reduced to the solution of constrained optimization problems, which is easily determined using in MS Excel. The results of the research have been outlined in this article, they are of considerable interest in applied researches. The article also formulated and the proposed method of solution of inverse in a dynamic Leontiev model
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01.00.00 Physical-mathematical sciences
Description
Micro and nanofluidics are the new multidisciplinary sciences. One of the tasks of which is creation and management of flow of fluid in the thin channels size of a few nano- or micrometer which exposed the external electric field, where the walls are the ion exchange membrane. Electroosmosis (electroconvection) plays an important role in these tasks. A large number of articless were devoted to electroosmosis. One of the first, Dukhin S.S., Mishchuk N.A. and Rubinstein I. gave a theoretical explanation of the overlimiting current by electroosmosis. They used two-dimensional Stokes equation to calculate the flow of the electrolyte, and one-dimensional equations of Nernst-Planck and Poisson to calculate the electric power. These researches have multiple limitations because of the computational complexity the mathematical simulation. Thus, there is an actual problem of the asymptotic solution of boundary value problems for the two-dimensional systems of equations of NernstPlanck and Poisson without these restrictions. These researches we derived in simplified models of electroosmosis in galvanic dynamical mode using the decomposition method. We have created a hierarchical system of two-dimensional mathematical models of ion transport of salt and electroosmosis in micro- and nanochannels formed by selective ion-exchange membranes
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01.00.00 Physical-mathematical sciences
Description
The article by continues the cycle of their studies related to the formulation and development of methods of constructing non-negative solutions of inverse problems of balance models (in this case, the model of world trade). Method of constructing nonnegative solutions of the studied inverse problems is developed. This technique is based on the following scheme of the solution. Initially we convinced of a correct formulation of the direct problem, then of the solvability of the inverse. Further, by specified tabular solutions of the direct problem, a system of algebraic equations containing the unknown, the estimated parameters of the studied model is built. Then the inverse problem reduces to solving the following quadratic programming, the solution of which is determined in MS Excel. The theoretical material is accompanied by solution of specific example, using statistical data of the Karachay-Cherkess Republic that shows how actually in practice it is possible to solve the inverse problem, i.e. to organize a process of balanced trade of the Karachay-Cherkess Republic with each of the subjects of Noth – Caucasion Federal District. Found the non-negative elements of a matrix, by which we can judge what proportion of national income, y, the subject has to spend on the purchase of goods in the Karachay-Cherkess Republic, to trade between this pair was balanced. So, the inverse problem posed in relation to the trading countries, it is possible to put and solve the following method and to trade between the subjects of one country
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GENERAL RELATIVITY AND THEORY OF ELECTROMAGNETIC DRIVE
01.00.00 Physical-mathematical sciences
Description
The article presents the theory of the electromagnetic type of rocket motor. The apparatus consists of a magnetron and a conical cavity in which electromagnetic oscillations are excited. We explain the mechanism of trust in such a device based on Maxwell's theory and the Abraham force. We built a dynamic model of the motor and calculated the optimal parameters. It is shown, that the laws of conservation of momentum and energy for the rocket motor of electromagnetic type are true, taking into account the gravitational field. In simulation, the movement used the theory of relativity. The source of the motion in an electromagnetic drive is the mass conversion in various kinds of radiation. The optimization of the operating parameters of the device is done, namely by the excitation frequency, the magnitude of heat losses of electromagnetic energy by thermal radiation in the IR spectrum, the parameters of heat transfer and forced from the temperature dependence of the resistance of the material of the cavity walls. It was found that the effective conversion of electromagnetic energy in the trust force necessary to minimize the deviation of the excitation frequency of the primary resonance frequency of the cavity. The mechanism of formation of trust under change the metrics of space-time, taking into account the contribution of the Yang-Mills theory and electromagnetic field tensor of energymomentum has been proposed
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01.00.00 Physical-mathematical sciences
Description
The article discusses the application of automated system-cognitive analysis (ASC-analysis), its mathematical model which is system theory of information and its software tool, which is intellectual system called "Eidos" for solving problems related to identification of types and models of aircraft by their silhouettes on the ground, to be more precise, their external contours: 1) digitization of scanned images of aircraft and creation of their mathematical models; 2) formation of mathematical models of specific aircraft with the use of the information theory; 3) modeling of the generalized images of various aircraft types and models and their graphic visualization; 4) comparing an image of a particular plane with generalized images of various aircraft types and models, and quantifying the degree of similarities and differences between them, i.e., the identification of the type and model of airplane by its silhouette (contour) on the ground; 5) quantification of the similarities and differences of the generalized images of the planes with each other, i.e., clusterconstructive analysis of generalized images of various aircraft types and models. The article gives a new approach to digitizing images of aircraft, based on the use of the polar coordinate system, the center of gravity of the image and its external contour. Before digitizing images, we may use their transformation, standardizing the position of the images, their sizes (resolution, distance) and the angle of rotation (angle) in three dimensions. Therefore, the results of digitization and ASC-analysis of the images can be invariant (independent) relative to their position, dimensions and turns. The shape of the contour of a particular aircraft is considered as a noise information on the type and model of aircraft, including information about the true shape of the aircraft type and its model (clean signal) and noise, which distort the real shape, due to noise influences, both of the means of countering detection and identification, and environment. Software tool of ASC-analysis, i.e. Eidos intellectual system, provides identification of the type and the model of airplane by its silhouette, as it was shown in a simplified numerical example
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01.00.00 Physical-mathematical sciences
Description
The question of construction of electrodynamics in the framework of the metric theory of gravitation is discussed. It is shown that the energy-momentum tensor of the electromagnetic field creates a space in which Faraday's law of induction is true. In such a space the scalar curvature vanishes identically, although space contains matter in the form of an electromagnetic field. It is proposed to call such space Faraday's magnetic universe as historically Faraday first established experimentally that "empty space is a magnet." We consider the metric of the expanding universe and metrics that describe the local gravitational field in the Newtonian theory. It was established that the field equations in spaces containing matter only in the form of an electromagnetic field in these metrics are reduced to hyperbolic equations describing the propagation of waves at the speed of light. However, in the field containing matter, the field equations are the equations of parabolic type, which describe diffusion or probability waves of Schrödinger quantum theory type. It is assumed that the potentials of the two metrics are connected, as with the potentials of the electromagnetic field, and the potentials of the Yang-Mills theory. Hence, the total output for all interactions law establishing the primacy of the gravitational field as the fundamental interaction, generating other interactions
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