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1

The use of a fuzzy expert system to increase the reliability of diagnostics of axle boxes of rolling stocks

Manafov Elshan

Zeszyty Naukowe. Transport / Politechnika Śląska

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2020

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z. 107

95--106

EN

This paper is devoted to the development of an effective system for monitoring the technical condition of the axle boxes of rolling stock. To this end, the possibility of solving problems of fault diagnostics based on the theory of fuzzy sets is considered. This allows one note such difficult-to-formalise factors as experience and intuition of a highly qualified expert specialist. It showed that an expert system-based monitoring approach allows evaluation of the technical condition of the axle boxes, characterised by internal and external operating uncertainty. It also proposed the use of parameters such as vibration and noise for comprehensive monitoring of the technical condition of axle box units together with temperature. Furthermore, the combination of these diagnostic parameters and expert system’s possibility to receive all necessary information about the condition of the most critical components of the axle boxes in real-time and analyse the changes in their operational parameters was explored. The stages of modelling an expert system in the Fuzzy Logic Toolbox package of the MATLAB computing environment are presented.

2

Multi-criteria group decision making model using single-valued neutrosophic set

Das Suman, Das Rakhal, Tripathy Binod Chandra

LogForum

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2020

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Vol. 16, no. 3

421--429

EN

Background: In this article, we introduce some approaches for decision making in the neutrosophic set. The purpose of this study is to develop a neutrosophic multi-criteria group decision-making (MCGDM) model based on hybrid score-accuracy functions for approving a tender for construction under a simplified neutrosophic environment. Five criteria have been selected from experts' opinions to be considered for the distribution of tender. In this paper, we use the score functions, the accuracy functions, and the hybrid score-accuracy functions of single-valued neutrosophic numbers (SVNNs) and ranking method for SVNNs, those will help for making a decision. Methods: Decision making under uncertain situation is an important aspect of those days. For this, we have developed the multi-criteria decision-making model using a single-valued neutrosophic set. The main aim is to select an appropriate tender for assigning the work to be done, so that the output will be the best one, under the available resources. Results: We have developed an algorithm for taking proper decisions for the selection of a contractor for the construction of a public/government work. Conclusions: We have verified our algorithm with the help of an example. We have considered five criteria. However, this algorithm can be applied for multi-criteria decision making. Also, it can be applied to other case studies too.

PL

Wstęp: W pracy przybliżono kilka rodzajów podejmowania decyzji w układzie neutrosoficznym. Celem pracy jest opracowanie modelu neutrosoficznego wielokryterialnego podejmowania decyzji (MCGDM) w oparciu o funkcje hybrydowej akuratności dla akceptacji ofert w uproszczonym neutrosoficznym środowisku. Wybrano pięć kryteriów na podstawie opinii ekspertów, które były użyte w trakcie budowania oferty. W trakcie badań zostały użyte funkcje oceny, akuratności, hybrydowe dla pojedynczych wartości neutrosoficznych (SVNNs) oraz metoda rankingu dla SVNNs. Służyły one jako wspomaganie do podejmowania decyzji. Metody: Podejmowanie decyzji w niepewnym środowisku jest istotnym czynnikiem współcześnie. W tym celu opracowano wielokryterialny model podejmowania decyzji przy zastosowaniu jednowartościowego układu neutrosoficznego. Wyniki: Opracowano algorytm podejmowania decyzji wyboru kontrahenta budowlanego dla zleceń rządowych. Wnioski: Opracowany algorytm został przetestowany na przykładzie. W analizie uwzględniono pięć kryteriów, niemniej jednak opracowany algorytm może być użyty do wielokryterialnego podejmowania decyzji.

3

BIBO stabilisation of continuous-time Takagi–Sugeno systems under persistent perturbations and input saturation

Salcedo J. V., Martínez M., García-Nieto S., Hilario A.

International Journal of Applied Mathematics and Computer Science

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2018

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Vol. 28, no. 3

457--472

EN

This paper presents a novel approach to the design of fuzzy state feedback controllers for continuous-time non-linear systems with input saturation under persistent perturbations. It is assumed that all the states of the Takagi–Sugeno (TS) fuzzy model representing a non-linear system are measurable. Such controllers achieve bounded input bounded output (BIBO) stabilisation in closed loop based on the computation of inescapable ellipsoids. These ellipsoids are computed with linear matrix inequalities (LMIs) that guarantee stabilisation with input saturation and persistent perturbations. In particular, two kinds of inescapable ellipsoids are computed when solving a multiobjective optimization problem: the maximum volume inescapable ellipsoids contained inside the validity domain of the TS fuzzy model and the smallest inescapable ellipsoids which guarantee a minimum *-norm (upper bound of the 1-norm) of the perturbed system. For every initial point contained in the maximum volume ellipsoid, the closed loop will enter the minimum *-norm ellipsoid after a finite time, and it will remain inside afterwards. Consequently, the designed controllers have a large domain of validity and ensure a small value for the 1-norm of closed loop.