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Упит dcterms_subject_txt:Fuzzy theory

207 items

  • Fuzzy expert analysis of the severity of mining machinery failure

    Dejan V. Petrović, Miloš Tanasijević, Saša Stojadinović, Jelena Ivaz, Pavle Stojković (2020)
    Mining machinery failure is almost an everyday occurrence. Usually the failures bare certain consequences, which require additional financial costs to repair and restore the system to its operational state. The consequences are viewed through negative and damaging effects a failure has on the machine, health and safety of the employees, work environment, and on the environment. The removal of the consequences of the failure requires additional financial investment, which has a negative impact on the company’s business. In order ...
    Severity of failure, Severity of failure assessment, Mining machinery, Fuzzy sets, Fuzzy logic

  • Application of the Fuzzy theory in the evaluation of operating parameters of auxiliary mechanization on open-cast coal mine, case study: pipelayers

    Stevan Djenadić, Miloš Tanasijević, Filip Miletić, Predrag Jovančić (2022)
    Achieved operating parameters are the main indicator of the work quality and selection of mining machines. The effectiveness of a coal mine is correlated with the availability of basic and auxiliary machines. The main task of auxiliary machines in lignite mines is to achieve optimal working conditions. From an economic point of view, auxiliary machines generate up to 20% of the lignite mines' total costs. These are the primary reasons for analyzing their current work and making decisions in ...
    upotrebni kvalitet, fazi teorija, rudarske mašine

  • Application of the Fuzzy Model in the Evaluation and Selection of Hydraulic Excavators on Open-Pit Lignite Mine

    Stevan Đenadić, Miloš Tanasijević, Vladimir Milisavljević, Dragan Ignjatović, Predrag Jovančić (2021)
    The production of lignite in large open-pit mines is mainly performed with continuously operating equipment, where bucket-wheel excavators, bucket-chain excavators, belt conveyors, and spreaders are the basic machines. Smaller machines, usually of discontinuous operating nature, are commonly categorized as auxiliary machines. This paper presents the research related to the analysis of auxiliary machine parameters with the case study for a hydraulic excavator. The purpose of the analysis was to develop a model of rating quality of service of the ...
    Fuzzy theory, hydraulic excavator, selection, quality of service, asset management

  • Fuzzy Model for Risk Assessment of Machinery Failures

    Dejan V. Petrović, Miloš Tanasijević, Saša Stojadinović, Jelena Ivaz, Pavle Stojković (2020)
    The main goal of this research was the development of an algorithm for the implementation of negative risk parameters in a synthesis model for a risk level assessment for a specific machine used in the mining industry. Fuzzy sets and fuzzy logic theory, in combination with statistical methods, were applied to analyze the time picture state of the observed machine. Fuzzy logic is presented through fuzzy proposition and a fuzzy composition module. Using these tools, the symmetric position of the ...
    fazi teorija, rizik, otkaz rudarskih mašina
    ... on fuzzy set theory that have been applied to safety and reliability, such as fuzzy FTA, fuzzy FMEA, fuzzy ETA, fuzzy Bayesian networks, fuzzy Markov chains, and fuzzy Petri nets. Similar analyses have been presented by Liu et al. [22]. Their review showed the potential applicability of fuzzy set ...
    ... industry. Fuzzy sets and fuzzy logic theory, in combination with statistical methods, were applied to analyze the time picture state of the observed machine. Fuzzy logic is presented through fuzzy proposition and a fuzzy composition module. Using these tools, the symmetric position of the fuzzy sets with ...
    ... industry. Fuzzy sets and fuzzy logic theory, in combination with statistical methods, were applied to analyze the time picture state of the observed machine. Fuzzy logic is presented through fuzzy proposition and a fuzzy composition module. Using these tools, the symmetric position of the fuzzy sets with ...

  • Razvoj modela upravljanja cirkulacijom u postupku bušenja korišćenjem neuro fazi sistema zaključivanja

    Seyed Ali S. Razeghi (2022)
    Gubitak isplake predstavlja nekontrolisano isticanje bušaćeg fluida kroz formacije kao što su kaverne, pukotine, ili drugi slojevi. Tradicionalne metode procene gubitka isplake se zasnivaju na primeni seizmičkih podataka ili pronalasku „mesta“ gubitka isplake na osnovu raspoloživih podataka iz susednih bušotina. Međutim, ove metode procene nisu pouzdane.‘ U disertaciji je izvršena analiza i procena uticaja parametara bušenja, geoloških faktora, karakteristika formacije i fluida na gubitak isplake kao i na formiranje fraktura u formacijama. Uspostavljeni su modeli koji podrazumevaju proces obrade ...
    naftna bušotina, gubitak isplake, fuzzy logika, ANFIS model

  • The Fuzzy–AHP Synthesis Model for Energy Security Assessment of the Serbian Natural Gas Sector

    Aleksandar R. Madžarević, Dejan D. Ivezić, Miloš L. Tanasijević, Marija A. Živković (2020)
    Natural gas is used for the production of almost 20% of total energy today. The natural gas security of the Republic of Serbia is an urgent strategic, political and security issue. Serbia is one of the most vulnerable countries in Southeast Europe, because it only has one supply route. This study is a contribution to efforts to better understand the factors affecting energy security through the implementation of a new methodology based on the fuzzy–AHP synthesis model for measuring ...
    energetska bezbednost, prirodni gas, fazi AHP, AHP višekriterijumska analiza, fazi teorija
    ... data to the fuzzy set, which is further analyzed in the fuzzy composition process. Fuzzy compositions represent a step in modeling using fuzzy set theory in which the process of integration and synthesis of partial influences at the synthetic level is performed. The process of compositing fuzzy relationships ...
    ... not have a strictly true/strictly false value. Fuzzy theory represents the concept of the value of truth that ranges from the notion of completely true to the notion of completely false (0–1) [43]. Fuzzy logic, as well as the accompanying theory of fuzzy sets, is tolerant of imprecise data and flexible ...
    ... possibility of integrating the analysis of qualitative and quantitative factors. Symmetry 2020, 12, 908 3 of 42 1.2. Energy Security and Fuzzy Theory Fuzzy theory finds its purpose in the analysis and modeling of complex systems, starting from the idea that complex problems can be solved if instead ...

  • A Fuzzy Expert Model for Availability Evaluation

    Dejan Ivezić, Miloš Tanasijević, Predrag Jovančić, Radiša Đurić (2019)
    Each technical system within itself carries the great potential danger of possible occurrence of failure and damages. Mining machines are characteristic by great investment values, costs of unplanned shutdowns, complex working conditions, and environment and workers hazards. Systematic monitoring of the mining machinery is of great importance for the management of the mining companies. Availability is the overall concept of quality of service. Includes information regard to operating state, an idle state, a standby state and shut down. The ...
    raspoloživost, ekspertski sistem, fazi teorija, buldozeri
    ... resultant. In literature, such problems are usually solved using fuzzy sets theory [3,7]. III. AVAILABILITY ASSESSMENT MODEL Figure 1 shows the conceptual model of the expert system for availability (A) evaluation based on fuzzy interference of reliability (R), maintainability (M) and supportability ...
    ... sets and fuzzy logic: theory and applications, Prentice-Hall, Inc. Upper Saddle River, NJ, USA [7] Kabir S., Papadopoulos Y., A review of applications of fuzzy sets to safety and reliability engineering, International Journal of Approximate Reasoning, Vol. 100, Pages 29-55, 2018. [8] Wang, J., Yang ...
    ... done. Conclusions can be used for maintenance, in logistics and during the purchasing of new machines. Keywords—availability, expert system, fuzzy theory, bulldozers I. INTRODUCTION Availability is defined as the ability of the technical system to be able to perform the required function, under ...

  • Fuzzy optimization in hydrodynamic analysis of groundwater control systems: Case study of the pumping station “Bezdan 1”, Serbia

    Dragoljub Bajić, Dušan Polomčić (2014)
    A groundwater control system was designed to lower the water table and allow the pumping sta-tion “Bezdan 1” to be built. Based on a hydrodynamic analysis that suggested three alternative solutions, mul-ticriteria optimization was applied to select the best alternative. The fuzzy analytic hierarchy process methodwas used, based on triangular fuzzy numbers. An assessment of the various factors that influenced the selec-tion of the best alternative, as well as fuzzy optimization calculations, yielded the “weights” of the alternativesand the ...
    groundwater lowering, groundwater management scenario, fuzzy analytic hierarchy process,expert knowledge, triangular fuzzy numbers, linguistic variables
    ... the fundamental theories of fuzzy triangular numbers, contributed an improved approach to their comparison, and demon- strated a practical application to an oil field. CHOU & LIANG (2001) proposed a fuzzy multicriteria decision- making concept that integrated the fuzzy theory with the analytic hierarchic ...
    ... y. Environmental Earth Science, 71 (6): 2559–2572. VAN LAARHOVEN, P.J.M. & PEDRCYZ, W. 1983. A fuzzy extension of Saaty’s priority theory. Fuzzy Sets and Sy- stems, 11: 229–241. ZADEH, L.A. 1965. Fuzzy Sets, Information and Control, 8 (3): 338–353. ZADEH, L.A. 1975. The concept of a linguistic variable ...
    ... number and types of applications of systems based on the fuzzy theory. While it was originally used to analy- ze data that allow for partial set membership, to avoid the approach where there is either full or no such mem- bership, today fuzzy logic is a management method which, despite its early stage ...

  • Development of the Availability Concept by Using Fuzzy Theory with AHP Correction, a Case Study: Bulldozers in the Open-Pit Lignite Mine

    Stevan Đenadić, Dragan Ignjatović, Miloš Tanasijević, Uglješa Bugarić, Ivan Janković, Tomislav Šubaranović (2019)
    Availability is one of the most used terms in maintainability engineering. This concept is used to denote: The quality of service of an engineering system, i.e., machines, weak points’ analysis, asset management, as well as making decisions in the process of life cycle management. Availability is an overall indicator and contains partial indicators that are oriented towards reliability, maintenance, and logistical support. Availability presents a variable value and changes in time and space. Usually, availability is shown as the ...
    raspoloživost, fazi teorija, AHP višekriterijumska analiza, eksperska ocena, buldozer
    ... integration, based on the theory of fuzzy sets, has been developed. Theories of fuzzy logic are specifically used for description and proposition of indicators, i.e., their composition in which prevail uncertainty, indefinitely, multiplicity, subjectivity and mutual over-lapping. Fuzzy logic is used as a ...
    ... System failure engineering and fuzzy methodology an introductory overview. Fuzzy Sets Syst. 1996, 83, 113–133. [CrossRef] 10. Miodragovic, R.; Tanasijevic, M.; Mileusnic, Z.; Jovancic, P. Effectiveness assessment of agricultural machinery based on fuzzy sets theory. Expert Syst. Appl. 2012, 39, 8940–8946 ...
    ... with hybrid data. Unlike the classic crisp logic, fuzzy values are defined with membership function to proper linguistic variables [3]. The max–min composition was used, where the outcomes were defined as the mean value. In reference [14], the fuzzy theory was also used for the synthesis of available ...

  • A fuzzy-based decision support model for effectiveness evaluation - a case study of examination of bulldozers

    Miloš Tanasijević, Predrag Jovančić, Dejan Ivezić, Uglješa Bugarić, Radiša Đurić (2019)
    Effectiveness evaluation is one of the basic components of engineering asset management and maintenance engineering in general. Effectiveness is an overall concept representing a measurement of quality of service level for the analyzed engineering system. This concept contains a series of partial indicators relating to time in operation and time for maintenance activities, as well as functional properties of the system. This article describes the analysis and structuring of partial indicators, as well as the development of a model ...
    Efikasnost, Fazi zaključivanje, Prikupljanje podataka, Buldozer

  • Determining the Availability of Continuous Systems at Open Pits Applying Fuzzy Logic

    Miljan Gomilanović, Miloš Tanasijević, Saša Stepanović (2022)
    This work presents a model for determining the availability of continuous systems at open pits by applying fuzzy logic and fuzzy inference systems. The applied model was formed by the synthesis of independent partial indicators of availability. The model is based on an expert system for assessing the availability of continuous mining systems. The availability of the system, as a complex state parameter, is decomposed into the partial indicators, reliability, and convenience of maintenance, and the fuzzy compositions, used ...
    системи, континуални систем експоатације, површински коп, рударство, расположивост, фази логика, max–min композиција, min–max композиција

  • Gate Road Support Deformation Forecasting Based on Multivariate Singular Spectrum Analysis and Fuzzy Time Series

    Luka Crnogorac, Rade Tokalić, Zoran Gligorić, Aleksandar Milutinović, Suzana Lutovac, Aleksandar Ganić (2021)
    Underground mining engineers and planners in our country are faced with extremely difficult working conditions and a continuous shortage of money. Production disruptions are frequent and can sometimes last more than a week. During this time, gate road support is additionally exposed to rock stress and the result is its progressive deformation and the loss of functionality of gate roads. In such an environment, it is necessary to develop a low-cost methodology to maintain a gate road support system. ...
    deformacije podgrade, lasersko skeniranje, višekanalna singularna spektralna analiza, prognoza, klasterisanje fuzzy vremenskih serija
    ... a defined universe of clustering, we apply the concept of fuzzy time series. Such series, which were first proposed by Song and Chissom, ref. [17] are based on fuzzy set theory proposed by Zadeh [18,19]. The most important advantage of fuzzy time series approaches is to be able to work with a very small ...
    ... a defined universe of clustering, we apply the concept of fuzzy time series. Such series, which were first proposed by Song and Chissom, ref. [17] are based on fuzzy set theory proposed by Zadeh [18,19]. The most important advantage of fuzzy time series approaches is to be able to work with a very small ...
    ... the Cumulative Probability Distribution Approaches. Entropy 2010, 12, 2397–2417. [CrossRef] 24. Kaufmann, A.; Gupta, M.M. Introduction to Fuzzy Arithmetic: Theory and Applications; Van Nostrand Reinhold: New York, NY, USA, 1985. http://doi.org/10.1016/j.tust.2014.12.006 http://doi.org/10.1007/s003 ...

  • A hundred years of Milutin Milanković's climate change theory - geological implications

    Dejan Radivojević (2020)
    Миланковићева теорија циклуса објављена пре сто година је најважнија теорија у наукама које проучавају климу и имала је велики утицај на дисциплине које се баве Земљом. Ипак, његов рад је чекао више од педесет година да би добио потврду. Може се рећи да Миланковићев рад највећи утицај на геологију има у изради астрономске временске скале, подршци хипотези континенталног дрифта и палеоклиматологији. Добри резултати примене астрономске временске скале на неогене седименте иницирали су примену ове методе у мезозојским и у последње ...
    циклостратиграфија, астономска временска скала, геолошка временска скала, климатске промене, континентални дрифт
    ... hundred years of Milutin Milanković's climate change theory - geological implications Dejan Radivojević Дигитални репозиторијум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] A hundred years of Milutin Milanković's climate change theory - geological implications | Dejan Radivojević | ...
    ... Geology, Kamenička 6, 11000 Belgrade, Serbia. E-mail: dejan.radivojevic@rgf.bg.ac.rs Abstract. Milanković’s cycles theory published hundred years ago is the most important theory in climate science and had great influence on Earth disci- plines. Nevertheless, his work waited for more than fifty years ...
    ... 2020). Conclusions Probably the most influential climatic study ever, Milanković’s “Mathematical Theory of Heat Phe- nomena Produced by Solar Radiation” was pub- lished hundred years ago. His theory affected geology and its different branches like stratigraphy, palaeoclimatology, tectonics etc. Recently ...

  • The theory of Hardys Z-function""""

    Ivić Aleksandar (2012)

  • Centenary anniversary of the theory of continental drift by Alfred Wegener and its significance for geosciences and the human society

    Rundić Ljupko (2012)

  • Effectiveness assessment of agricultural machinery based on fuzzy sets theory

    Miodragović Rajko, Tanasijević Miloš, Mileusnić Zoran, Jovančić Predrag (2012)

  • Application of rough set theory for choosing optimal location for flotation tailings dump

    Štirbanović Zoran, Miljanović Igor, Marković Zoran (2013)

  • The divisor function and divisor problem, presented at the Erdös Centennial Conference “ERDOS100” Budapest 2013

    Ivić Aleksandar (2014)

  • Analysis of Household Coal Consumption in Serbia Based on Grey System Theory and K - means Clustering (Base for Network Optimization)

    Gligorić Zoran, Gligorić Miloš, Štrbac-Savić Svetlana (2015)

  • Quantification of Uncertainty in Mining Project Related to Metal Price Using Mean Reversion Process and Interval Type-2 Fuzzy Sets Theory

    Gligorić Zoran, Beljić Čedomir, Gluščević Branko (2013)