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Упит dcterms_subject_txt:key block theory

272 items

  • 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
    ... outcomes were defined as the mean value. In reference [14], the fuzzy theory was also used for the synthesis of available parameters, but reliability and the convenience of maintenance are presented on the basis of probability theory. Therefore, the concept of the fuzzification of the cumulative function ...
    ... Измењено: 2023-10-14 04:29:43 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 ...
    ... Дигитални репозиторијум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] 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 ...

  • Permanent GNSS monitoring of landslide Umka

    Mileva Samardžić Petrović, Jovan Popović, Uroš Đurić, Biljana Abolmasov, Marko Pejić, Miloš Marjanović (2020)
    Клизиште Умка је једно од највећих насељених активних клизишта у Србији. Активност клизишта Умка се прати већ више од 85 година, различитим геотехничким и геодетским техникама. Од 2010. године, активност kлизишта се континуирано прати у реалном времену аутоматизованим перманентним системом за праћење базираним на Глобалним навигационим сателитским системима (ГНСС). Поред тога, од 2018. године активност клизишта се додатно прати кинематичким ГНСС одређивањем положаја скупа карактеристичних тачака као и применом UAV фотограметрије. Главни циљ овог рада је приказ резултата опажања три ...
    клизиште, перманентно праћење, ГНСС
    ... | Mileva Samardžić Petrović, Jovan Popović, Uroš Đurić, Biljana Abolmasov, Marko Pejić, Miloš Marjanović | International Conference on Contemporary Theory and Practice in Construction XIV Stepgrad | 2020 | | 10.7251/STP2014091S http://dr.rgf.bg.ac.rs/s/repo/item/0005205 Дигитални репозиторијум Руд ...
    ... as the employees' publications. - The Repository is available at: www.dr.rgf.bg.ac.rs 91 PROCEEDINGS OF INTERNATIONAL CONFERENCE ON CONTEMPORARY THEORY AND PRACTICE IN CONSTRUCTION XIV PERMANENT GNSS MONITORING OF LANDSLIDE UMKA 10 | Research paper I Оригинални научни рад ISSN 2566-4484 ...
    ... карактеристичних тачака клизишта Умка. Кључне ријечи: клизиште, перманентно праћење, ГНСС 92 PROCEEDINGS OF INTERNATIONAL CONFERENCE ON CONTEMPORARY THEORY AND PRACTICE IN CONSTRUCTION XIV PERMANENT GNSS MONITORING OF LANDSLIDE UMKA 1. INTRODUCTION Over the past two decades, driven by the ...

  • 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

  • A Knowledge-Based Approach to Mine Ventilation Planning in Yugoslav Mining Practice

    Nikola Lilić, Ivan Obradović, Ranka Stanković (2002)
    Ventilation system analysis is a complex process based on the calculation and analysis of numerous parameters. These problems can be successfully solved by the SimVent numerical package, but a full understanding and use of the obtained results require the involvement of an experienced specialist in the ventilation field. The solution was found in the creation of a hybrid system INVENTS, whose knowledge base represents a formalization of the expert knowledge in the mine ventilation field. In this paper, we ...
    ... following: (i) a block for the analysis of air flow and pressure distribution in the ventilation network, (ii) a block for the analysis of climate conditions in mine workings, (iii) a block for temperature and heat depression analysis in fire incidence condi- tions, and (iv) a block for gas distribution ...
    ... as system structure and user interface. 1. Introduction The methodology of mine ventilation planning and design in contemporary Yugoslav mining theory and practice differs substantially from the traditional approach. Novel approaches take full advantage of the possibilities offered by computer hard- ...
    ... hard- ware and software that are at the disposition of mine engineers. Software packages for mine ventilation simulation are now playing a key role in the process of mine ventilation planning and design.7–10 In this paper, we propose a six-step approach to the solution of mine ventilation design ...

  • Simple 2D Gravity-density inversion for modeling of the sedimentary basin basement

    Ivana Vasiljević, Snežana Ignjatović, Dragana Đurić, (2019)

  • Clockwise vertical-axis rotation in the West Vardar zone of Serbia: Tectonic implications

    Vesna Lesić, Emo Márton, Violeta Gajić, Dragana Jovanović, Vesna Cvetkov (2018)
    The Vardar-Tethyan mega-suture between the Eurasian and Adria (Gondwana) margins comprises remnants of oceanic lithosphere of Neotethys and distal parts of the adjacent continental margins including unconformable Late Cretaceous sedimentary cover and Cenozoic igneous rocks of post-obduction age. This study provides kinematic constraints for displacements and rotations affecting the Serbian part of the West Vardar and Jadar-Kopaonik units after the closure of the Neotethyan (= Sava) Ocean. The targets of the paleomagnetic research were Late Cretaceous sediments representing an ...
    Paleomagnetism, Clockwise rotation, Dinarides, West Vardar zone
    ... (2006), following a terrane concept, define a Western Vardar zone that docked with the Jadar block at the end of the Cretaceous, and the main Vardar zone. Between these two zones he defined the Kopaonik Block and Ridge unit. Schmid et al. (2008) distinguishes a Western and an Eastern Ophiolite belt ...
    ... parison between the different subdivisions). Almost all of the localities/sites sampled by us belong to the Western Vardar zone, Jadar block and Kopaonik Block and Ridge unit sensu Karamata (2006), or in other words to the West Vardar and Jadar–Kopaonik units sensu Schmid et al. (2008). Only a ...
    ... between these two dif- ferently behaving, relatively rigid areas to constrain pos- sible rotations which could have affected the Vardar zone en block or different parts of it in different ways. This paleomagnetic study focuses on Upper Cretaceous sediments and Oligocene to Miocene magmatic rocks ...

  • 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
    ... of fuzzy set theory in addressing uncertainty in safety and reliability engineering. The numerous possibilities for applying fuzzy sets and fuzzy logic theory can be seen in the aforementioned research. The prospect theory is also used for risk assessment. The prospect (PT) theory proposed by Kahneman ...
    ... Fuzzy set theory represents a mathematical approach that is suitable for the analysis of processes in which uncertainty, ambiguity, subjectivity, and indeterminacy are prevalent. It was developed to treat insufficiently precise phenomena that cannot be modeled solely using probability theory or interval ...
    ... phenomenon being modeled: • Probability theory, when the given conditions that characterize the term do not determine a unique expected result; • Interval mathematics, when it is not possible (or necessary) to precisely determine the observed values; or • Fuzzy set theory, when the ambiguity arises from ...

  • Application of Project Management Process on Environmental Management System Improvement in Mining-Energy Complexes

    Jelena Malenović Nikolić, Dejan Vasović , Ivana Filipović , Stevan Mušicki, Ivica Ristović (2016)
    menadžment, rudrastvo i energetski kompleksi, okruženje, održivi razvoj, mrežno planiranje
    ... presented in the Reports on emission tests, measured in flues of TPP “Kostolac A” block 1, boiler 1; TPP “Kostolac A” block 1, boiler 2; TPP “Kostolac A” block 2; TPP “Kostolac B”, block 1; and TPP “Kostolac B”, block 2, indicate that the recorded values were higher than the prescribed emission limit ...
    ... criteria for determination of key problems in the functioning of environmental protection system in a mining and energy complex, in the case of surface mine and thermal power plant “Kostolac” in the Republic of Serbia [23].Energies 2016, 9, 1071 6 of 20 Figure 1. Defining key problems in operation of ...
    ... of the soil humus layer, and rehabilitation of degraded soils [14]. In order to reduce emissions of particulate matter, electrostatic filters in block B1 in TPP “Kostolac B” were reconstructed. In the thermal power plant “Kostolac B”, in blocks B1 and B2, the final phase of flue gas desulfurization ...

  • Adsorption and Polymerization of Aniline on Cu(II)-Montmorillonite:  Vibrational Spectroscopy and ab Initio Calculation

    M. Ilić, E. Koglin, A. Pohlmeier, H. D. Narres, M. J. Schwuger (2000)
    Batch adsorption experiments in the presence of oxygen were performed to study the interlayer reactions of aniline on Cu(II)-montmorillonite in aqueous solutions. At concentrations below a critical value of CC ) 2.6 mmol dm-3 only a colored Cu(II)-aniline complex is formed, characterized by a stability constant of log(Kassoc/dm3 mol-1) ) 1.5. At concentrations beyond Cc aniline polymerizes yielding a dark brown product, which is identified by two vibrational spectroscopy techniques, attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and ...
    Анилин, адсорпција, полимеризација, Cu(II)-Монтморилонит, ФТИР, аб инитио прорачун

  • Modeliranje tehnoloških procesa u rudarstvu u uslovima nedovoljnosti podataka primenom teorije grubih skupova

    Zoran M. Štirbanović (2015-07-01)
    Rudarstvo, a u okviru njega i priprema mineralnih sirovina, se odlikuje složenošću tehnoloških procesa što je posledica velikog broja uticajnih parametara. Samim tim je potrebno biti veoma obazriv prilikom donošenja odluka u oblasti rudarstva. U cilju što efikasnijeg funkcionisanja procesa, moguće je primeniti različite metode koje služe za pojednostavljenje procesa odlučivanja. Jedna od takvih metoda jeste i teorija grubih skupova. Ona predstavlja relativno novu matematičku teoriju koja je pogodna za razumevanje nepreciznih i nepotpunih podataka kao i za otkrivanje ...
    rudarstvo, priprema mineralnih sirovina, teorija grubih skupova, višekriterijumsko odlučivanje, flotacijsko jalovište, flotacijski kolektor, flotaciona mašina
    ... n coefficients demonstrate the high sensitivity of the rough set theory in terms of multi-criteria decision-making and define its usefulness in terms of insufficiency of data. Key words: mining, mineral procesing, rough set theory, multi-criteria decision-making, flotation tailings landfill, flotation ...
    ... decision-making process. One such method is the rough set theory. It is a relatively new mathematical theory that is suitable for understanding imprecise and incomplete data as well as to detect relationships between these data. The rough set theory has found application in various areas of industry, however ...
    ... In this way, rough set theory was applied for solving the given problems. Finally, results obtained by rough set theory, were verified by multi-criteria decision-making methods: VIKOR, AHP, ELECTRE, PROMETHEE and TOPSIS. Based on results it was concluded that rough set theory was successfully applied ...

  • Mio-Pliocene Geodynamics and its Stratigraphic Consequences in the Area of Avala Mt. (Belgrade, Serbia)

    Ljupko Rundić, Meri Ganić, Slobodan Knežević, Dejan Radivojević (2017)
    ... °e resulting stratigraphic data are interpreted in the context of Neoalpine geodynamics and revealed a complex tectonic structure with pronounced block structures. In the studied area, during the Neoalpine tectonics the signiºcant diµerential movement (uplift/downthrown) was present that have shaped ...
    ... movements have been occured during the Late Miocene and Pliocene and probably in the older Pleistocene. Due to the mentioned vertical movements along the block structures, a composite hilly relief with dominant the Torlak hill and the Beli potok valley was formed. EREMIJA, M. (1977): Miocen u oblasti eksumiranog ...

  • Анализа одрона у стенским косинама: савремени приступи

    Милош Марјановић (2023)
    У Србији и региону познате су бројне појаве одрона које су изазвале велике застоје саобраћаја, материјалне штете или чак имале фаталне исходе, па их је потребно непрестано пратити и изучавати. Mодeловањe одрона скопчано је са ниским нивоом поузданости, али савремене технологије омогућавају да сe такви изгледи донекле побољшају. Једна од технологија која чини искорак утом правцу јe LiDAR-ско скенирање, које обезбеђује детаљне топографске подлоге у виду облака тачака високе резолуције и тачности. Поступак анализе одрона може се свести на: ...
    одрони, осматрање, LiDAR, облак тачака, моделовање

  • 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

  • On the Rankin-Selberg problem in short intervals

    Ivić Aleksandar (2012)

  • A Mathematical Learning Environment Based on Serbian Language Resources

    Radojičić Marija, Obradović Ivan, Stanković Ranka, Utvić Miloć, Kaplar Sebastijan (2018)
    In recent years, in line with ever growing usage of Information technology, the learning environments are changing. The amount of available learning materials in various forms has increased. These new environments demand comprehensive learning systems, which enable management of the learning corpus with special attention paid to relevant lexical resources. In this paper we present the concept of a Mathematical Learning Environment in Serbian (MLES), which is based on a corpus of mathematical materials and various lexical resources, enabling ...
    mathematical content, text processing, mathematical formulae
    ... project is MathGo! that provides search and presentation of mathematical encoded text [8]. The software solution is based on the concepts of math block identification and vector representation, with special attention paid to the search of mathematical topics using clusters and relevance ranking ...
    ... are several projects reported which are similar to MLES. Three interesting systems are presented in [5],[6]. MMT is a system that includes the theory graphs as the modular representation paradigm for mathematical knowledge. MathHub.info is an archive system for encoded knowledge and MathWebSearch ...

  • 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
    ... 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 ...
    ... model, that integrates reliability, maintainability, and supportability in the measure of availability is proposed. This model is based on fuzzy sets theory and it is implemented to three types of bulldozers that operate at the lignite mines. Obtained results are used for the improvement of maintenance ...
    ... consideration operators’ opinions and judgments, and how to get a relevant 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 ...

  • 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

  • Spin activity correlations in driven disordered systems

    Đorđe Spasojević, Sonja Radić, Dragutin Jovković, Sanja Janićević (2022)
    Statistics, Probability and Uncertainty, Statistics and Probability, Statistical and Nonlinear Physics

  • 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
    ... AHP multi-criteria analysis; fuzzy theory 1. Introduction Energy is an essential ingredient for the world’s development. Energy represents a vital source of power for all social and economic activities and a unique part of the sustainable development puzzle. A key priority for almost all countries is ...
    ... AHP multi-criteria analysis; fuzzy theory 1. Introduction Energy is an essential ingredient for the world’s development. Energy represents a vital source of power for all social and economic activities and a unique part of the sustainable development puzzle. A key priority for almost all countries is ...
    ... mutual interaction [38]. Multi-criteria decision-making (MCDM) methods integrated with fuzzy set theory have been widely used to deal with uncertainty in the energy field decision process [39–41]. The key reason is finding an appropriate language to manage imprecise criteria and the possibility of integrating ...

  • Landslide Umka – The first GNSS monitoring project in Serbia

    Abolmasov Biljana, Milenković Svetozar, Jelisavac Branko, Vujanic Vladeta (2012)