Calculation integral reliability indicator of the urban electric transport traction electrical equipment

When reliability requirements at the stage of developing complex technical systems are setting, the total number of individual and complex reliability indicators set in accordance with regulatory documents is within 5-7 units. This is done provided that they are recoverable, and also for them the requirements for durability and preservation are determined. All this determines the complexity of the procedure for their verification, confirmation and evaluation. Aim: Formation of a common (integral) indicator of reliability, which can characterize the basic reliability properties multitude of traction electrical equipment, as a complex technical system, subject to the compliance of individual indicators with the requirements specified in the terms of reference. Methods: It is proposed to use of T. Saati's hierarchy analysis method, which is widely used in solving various multicriteria problems. Conclusion: Using an integral indicator to determine the level of reliability allows getting a formalized result, expressed through the vectors of global priorities corresponding value, which makes it possible to get a quantitative assessment of the superiority for one of alternative traction electrical equipment.

LEXICOGRAPHIC PROBLEMS OF CONVEX OPTIMIZATION: SOLVABILITY AND OPTIMALITY CONDITIONS, CUTTING PLANE METHOD

The lexicographic approach for solving multicriteria problems consists in the strict ordering of criteria concerning relative importance and allows to obtain optimization of more important criterion due to any losses of all another, to the criteria of less importance. Hence, a lot of problems including the ones of com­plex system optimization, of stochastic programming under risk, of dynamic character, etc. may be presented in the form of lexicographic problems of opti­mization. We have revealed conditions of existence and optimality of solutions of multicriteria problems of lexicographic optimization with an unbounded convex set of feasible solutions on the basis of applying properties of a recession cone of a convex feasible set, the cone which puts in order lexicographically a feasible set with respect to optimization criteria and local tent built at the boundary points of the feasible set. The properties of lexicographic optimal solutions are described. Received conditions and properties may be successfully used while developing algorithms for finding optimal solutions of mentioned problems of lexicographic optimization. A method of finding lexicographic of optimal solutions of convex lexicographic problems is built and grounded on the basis of ideas of method of linearization and Kelley cutting-plane method.

Aviation radio control systems as complex technical systems. Part 1. Analysis of the possibilities of multicriteria optimization

The need to take into account the increasing requirements for expanding the field of application conditions, taking into account an increasingly wide range of possible conditions, increasing requirements for the volume and reliability of the information used, combined with increasing requirements for improving the efficiency of operation, predetermined the emergence of a new type of information management systems, called "complex technical systems" (CTS). In general, the CTS is understood as a set of functionally related control and information subsystems united by a common goal of joint solution of a group of tasks. The most striking example of CTS is aviation radio control (RC) systems, which are able to solve the general task of destroying targets in several stages, using various methods of route control and guidance on them in conditions of high initial uncertainty due to a variety of possible objects of influence of varying degrees of importance and the random nature of their spatial location. At the same time, the task of destroying objects of the opposing side is solved, as a rule, in several stages, including long-range (command), short-range guidance (homing) and the use of weapons. It should be emphasized that the choice of indicators of excellence that reflect various aspects of the functioning of the CTS (aircraft RC systems) is by no means a trivial task. Within the framework of the "system – environment" approach, which takes into account the specific conditions of the use of the CTS, in addition to performance indicators that reflect the degree of compliance of the system with its purpose, such indicators as functional stability (survivability), dynamism and informativeness are increasingly in demand, which, as a rule, contradict each other. It should be noted that due to the heterogeneity of the tasks being solved and the inconsistency of the requirements, it is necessary to take into account the need to use a multicriteria approach to the synthesis of control methods and information support algorithms. However, the methods of multicriteria optimization used in practice have a number of significant drawbacks that make it difficult to use them in the development of promising CTS (RC systems). At the same time, it is very tempting to use the mathematical apparatus of the statistical theory of optimal control (STOC) for multicriteria optimization of the CTS, which allows to avoid the above disadvantages to some extent. The expediency of using STOC for solving multicriteria problems is due to the fact that the very formulation of the STOC problem and the resulting optimization procedures already contain a solution to the two-criterion problem of obtaining a system that is jointly the best in both accuracy and costeffectiveness of management. The analysis of various approaches to solving multicriteria problems has shown that the most rational is to reduce them to a singlecriteria problem with further use as a basic variant of local STOC optimization.

Zoning methodology for estimating the service life of the vehicle

The article presents a comprehensive method for removing uncertainty when solving multicriteria problems of vehicle maintenance. The task of the control system for the service life of the car is formed, and its characteristics are also highlighted. The main provisions of the zoning method are formulated from the point of view of the hierarchical correlation of the probabilities of the state of the external environment. The dynamics of changes in the quality indicators of cars in a multicriteria setting is estimated.

Penerapan Metode VIKOR Pada Pengambilan Keputusan Seleksi Calon Penerima Beasiswa di SMK TPI Al-Hassanah Pematang Bandar

The purpose of this research is to build a decision support system that can be used by schools in the selection of scholarship recipients, which requires completion, as decision support with multicriteria is the VIKOR method. The basic concept of the VIKOR method is to determine the ranking of the existing samples. This study aims to apply the VIKOR method to the selection of scholarship recipients that can be used to assist the student section in determining the recommendation for scholarship acceptance at SMK TPI AL-HASANNAH Pematang Bandar by considering various predetermined criteria. The criteria used in this study are value, parent's income, parent's dependents, number of siblings. The results show that the VIKOR method can be used to assist the selection process and determine the right scholarship recipient. In the VIKOR method, each weight given shows the same results, so that it can be used as a compromise solution in dealing with multicriteria problems.

On the Practical Consideration of Evaluators’ Credibility in Evaluating Relative Importance of Criteria for Some Real-Life Multicriteria Problems: An Overview

A multicriteria (MC) problem usually consists of a set of predetermined alternatives or subjects to be analyzed, which is prescribed under a finite number of criteria. MC problems are found in various applications to solve various area problems. There are three goals in solving the problems: ranking, sorting or grouping the alternatives according to their overall scores. Most of MC methods require the criteria weights to be combined mathematically with the quality of the criteria in finding the overall score of each alternative. This chapter provides an overview on the practical consideration of evaluators’ credibility or superiority in calculating the criteria weights and overall scores of the alternatives. In order to show how the degree of credibility of evaluators can be practically considered in solving a real problem, a numerical example of evaluation of students’ academic performance is available in the Appendix at the end of the chapter. The degree of credibility of teachers who participated in weighting the academic subjects was determined objectively, and the rank-based criteria weighting methods were used in the example. Inclusion of the degree of credibility of evaluators who participated in solving multicriteria problems would make the results more realistic and accurate.

Optimization Problem

A systemic approach to solving multicriteria optimization problems is proposed. The system approach allowed uniting the models of individual schemes of compromises into a single integrated structure that adapts to the situation of adopting a multi-criteria solution. The advantage of the concept of non-linear scheme of compromises is the possibility of making a multicriteria decision formally, without the direct participation of a person. The apparatus of the non-linear scheme of compromises, developed as a formalized tool for the study of control systems with conflicting criteria, makes it possible to solve practically multicriteria problems of a wide class.