Претрага

Упит dcterms_subject_txt:Severity of failure

2837 items

  • Adaptive neuro-fuzzy prediction of operation of the bucket wheel drive based on wear of cutting elements

    Filip Miletić, Predrag D. Jovančić, Milos Milovančević, Dragan Ignjatović (2020)
    The capacity of the rotor excavator depends largely on the operation of the subsystem for digging. There is a great contribution to the correct and sharp teeth when the capacity is the highest. In the function of time, the teeth become clogged due to abrasive wear, or changes in their geometric shape. To analyze the bucket wheel drive in depend on wear of the cutting elements in this study adaptive neuro fuzzy inference system (ANFIS) approach was implemented. ANFIS ...
    Pogon rotornog točka, habanje, rezni elementi, ANFIS

  • 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
    ... Liebherr in terms of R, with grades "good" in extent of 40% and “average” in extent of 60%; M as "average" in extent of 100% and S as "adequate" in extent of 100%; machine Dressta as "average" in all terms and Caterpillar as "good" in terms of R and S and "excellent" in term of M. This can be written ...
    ... 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 ...
    ... Industry of Serbia Kostolac, Serbia radisa.duric@te-ko.rs Predrag Jovancic Faculty of Mining and Geology University of Belgrade Belgrade, Serbia predrag.jovancic@rgf.bg.ac.rs Abstract—Each technical system within itself carries the great potential danger of possible occurrence of failure ...

  • A Model for Determining the Dependability of Continuous Subsystems in Coal Mines Using the Fuzzy Logic Approach

    Nikola Stanić, Miljan Gomilanović, Petar Marković, Daniel Krzanović, Aleksandar Doderović, Saša Stepanović (2024)
    This study presents a unique model for assessing the dependability of continuous parts of combined systems in open-pit mining through the application of fuzzy logic. Continuous sub-systems as part of the combined system of coal exploitation in surface mines have the basic function of ensuring safe operation, high capacity with high reliability, and low costs. These subsystems are usually part of the thermal power plant’s coal supply system and ensure stable fuel supply. The model integrates various independent partial ...
    fuzzy logic, max-min composition, continuous part of combined system (CCS), open pit, mining, dependability

  • Effectiveness Analysis of Different Bucket-wheel Excavators

    Stevan Đenadić, Predrag Jovančić, Dragan Ignjatović, Miloš Tanasijević, Filip Miletić (2021)
    Coal production in open-pit lignite mines in the Republic of Serbia is performed with continuous work systems. In addition to coal production, the same systems are used for the exploitation of large quantities of overburden. According to the reliability concept, continuous systems are in linear connection. If the failure occurs in one part of the system, that will produce a downtime of the entire system. The initial and most important factor of continuous systems is the bucket-wheel excavator. It ...
    bucket-wheel excavator, open-pit coal mine, mining, multi-criteria decision methods

  • Multiple-Criteria Decision-Making in Mine Development Planning

    Sanja Bajić (2023)
    The Borska Reka ore deposit is an experimental location where developed methodologies have been applied. It is the largest ore body within the Bor mining complex, which has been the subject of numerous studies and analyses for more than three decades. The paper focuses on the application of FAHP and the VIKOR method to address ranking of alternatives and select the optimal mining method by means of fuzzy multicriteria optimization.

  • Quantitative analysis of syllable properties in Croatian, Serbian, Russian, and Ukrainian

    Biljana Rujević, Marija Kaplar, Sebastijan Kaplar, Ranka Stanković, Ivan Obradović, Jan Mačutek (2021)
    slogovi, distribucija rang-preciznost, slovenski jezici

  • Automatic construction of a morphological dictionary of multi-word units

    Cvetana Krstev, Ranka Stanković, Ivan Obradović, Duško Vitas, Miloš Utvić (2010)
    The development of a comprehensive morphological dictionary of multi-word units for Serbian is a very demanding task, due to the complexity of Serbian morphology. Manual production of such a dictionary proved to be extremely time-consuming. In this paper we present a procedure that automatically produces dictionary lemmas for a given list of multi-word units. To accomplish this task the procedure relies on data in e-dictionaries of Serbian simple words, which are already well developed. We also offer an evaluation ...
    electronic dictionary, Serbian, morphology, inflection, multiwordn units, noun phrases, query expansion
    ... case of toponyms all cases of failure are due to the fact that components of toponyms were not simple words in Serbian (e.g. Feja in Kriva Feja). The lowest rank of a successful result was 6 for common nouns, and 2 for toponyms. Table 5. Evaluation of the strategy for nouns applied on a list of MWU common ...
    ... gives percentages of successfully produced noun and adjectives en- tries (case a), partially successful results (case b) and failures (case c), and also indicates the rank of these results (rank 0 means no solution offered). A failure means that either no solution was offered or none of the solutions was ...
    ... Duško Vitas3, and Miloš Utvić1 1 Faculty of Philology, University of Belgrade 2 Faculty of Mining and Geology, University of Belgrade 3 Faculty of Mathematics, University of Belgrade Abstract. The development of a comprehensive morphological dictio- nary of multi-word units for Serbian is a very demanding ...

  • Numerical modeling of Selanac debris flow propagation using SPH code

    Jelka Krušić, Biljana Abolmasov, Miloš Marjanović, Manuel Pastor, Saeid M. Tayyebi (2021)
    The Selanac debris flow is a very huge event triggered after extreme rainfall caused by Cyclone Tamara activity in the Republic of Serbia in May 2014. The Selanac case study was already modelling in different programs using Voellmy rheology assumptions like RAMMS software. In this paper research are focusing particularly on the process of debris flowing from initiation zone to main deposition area using Geoflow SPH two-phase model considering frictional rheology law. Main rheological parameters are back-calculated using also ...
    debris flow, modelling, SPH code, DEM
    ... first-failure flow type landslides especially across the Western Serbia. Most of these occurrences were defined as granular flows, which were not a typical landslide mechanism for this area. One such example is Selanac debris flow, which stands among the largest occurrence of this type of landslides ...
    ... discussed by Pastor et al. (2009) considering: A. balance of mass of the mixture—propagating along the slope and increasing due to bed entrainment—combined to the balance of linear momentum of pore water, B. the balance of linear momentum of the mixture, C. a kinetic relation between the defor ...
    ... mechanical behavior of the mixture can be described by a system of differential equations governing the dynamics of each of the phases as well as the coupling among them (Pastor et al, 2008). SPH (Smoothed Particle Hydrodynamics) is a mesh- less approach, widely used in different fields of research, and ...

  • Production of morphological dictionaries of multi-word units using a multipurpose tool

    Ranka Stanković, Ivan Obradović, Cvetana Krstev, Duško Vitas (2011)
    The development of a comprehensive morphological dictionary of multi-word units for Serbian is a very demanding task, due to the complexity of Serbian morphology. Manual production of such a dictionary proved to be extremely time-consuming. In this paper we present a procedure that automatically produces dictionary lemmas for a given list of multi-word units. To accomplish this task the procedure relies on data in e-dictionaries of Serbian simple words, which are already well developed. We also offer an evaluation ...
    electronic dictionary, Serbian, morphology, inflection, multi-word units, noun phrases, query expansion
    ... amounts to as much as 38.61%. All of the failures in the case of toponyms resulted from the absence of one or more of its components from dictionaries of simple words in Serbian (e.g. in Gornji Tavankut, Tavankut is not used independently), which is in line with failure causes in the experiment with ...
    ... words. In a much smaller number of Fig. 7. Results obtained on the second set of test data (in%) cases (20%) the incorrect solution resulted from the system’s failure to cover a specific MWU structure. With the second set of test data (nouns collected from various sources) we proceeded as follows. ...
    ... functionality of LeXimir, and makes use of our comprehensive e- dictionaries of Serbian simple words. We present an evaluation of the performance of this functionality, and hence of our procedure, obtained from experiments on two types of data. Finally, we discuss some further possible applications of our procedure ...

  • Geotechnical conditions of “Debelo brdo” tunnel construction on the highway E-80: Nis-Merdare-Pristina (“Peace Highway”)

    Dragoslav Rakić, Irena Basarić Ikodinović, Radojica Lapčević, Dragan Lukić (2024)
    The construction of the highway E-80 has begun in Serbia, which will represent the traffic hub of the Western Balkans and will be part of the main regional transport network of Southeast Europe. Its total length through Serbia is 77 km, and one part of the route is designed through a typical plain terrain, while a larger part of the route passes through hilly terrain. The construction of the tunnel “Debelo brdo” is planned partly in an open cut ...
    „Debelo brdo“ tunnel, temporary slopes, open cut excavation, tunnel excavation, piles

  • Primena termografije u rudarstvu

    Stevan Đenadić, Vesna Damnjanović, Predrag Jovančić, Dragan Ignjatović, Dragutin Jovković, Filip Miletić (2019)
    Danas, gotovo da nema oblasti u nauci i tehnici u kojoj se Infracrvena termografija ne primenjuje kao metoda za lociranje i praćenje zagrejanih objekata ili tela, beskontaktnu procenu temperature površina, i nedestruktivno ispitivanje materijala. U radu su prikazane mogućnosti i perspektive primene ove metode u oblasti rudarstva.
    infracrvena termografija, rudarstvo, monitoring
    ... N., Application of infrared thermography and geophysical methods for defect detection in architectural structures, Engineering Failure Analysis, Vol. 12, pp. 875-892, 2005. [5] Tomic Lj., Kovacevic A., Damnjanovic V., Osmokrovic P., Probability density function estimation of a temperature field ...
    ... Inspections of Mechanical Components. URL:https://www.infratec-infrared.com/thermography/industries- applications/maintenance-of-mechanical-assemblies/ [10] Zhai X., Wu S., Wnag K., Drebenstedt C., Zhao J., Environmental influences and extinguish technology of spontaneous combustion of coal gangue ...
    ... радовима запослених доступним у слободном приступу. - Претрага репозиторијума доступна је на www.dr.rgf.bg.ac.rs The Digital repository of The University of Belgrade Faculty of Mining and Geology archives faculty publications available in open access, as well as the employees' publications. - The Repository ...

  • Models of Determining the Parameters of Rock Mass Oscillation Equation with Experimental and Mass Blastings

    Suzana Lutovac, Branko Gluščević, Rade Tokalić, Jelena Majstorović, Čedomir Beljić (2018)
    ... as Failure Precursor Phenomenon for Seismic Activity Monitoring, Fracture, Fatigue, Failure, and Damage Evolution; Springer: Cham, Switzerland; Heidelberg, Germany; New York, NY, USA; Dordrecht, The Netherlands; London, UK, 2015; Volume 5, pp. 221–229. 2. Kahriman, A. Analysis of Parameters of Ground ...
    ... Parameters through the Application of Quotient of Products of the Same Number of Reduced Distances and Oscillation Velocities According to this model, determination of the parameter n is based on the quotient of the product of equal number of experimental data of the rock mass oscillation velocity v ...
    ... detonation of explosive materials is followed by release of a large amount of energy. Whereby, a greater part of energy is used for rock destruction, and part of energy, in the form of seismic wave, is lost in the rock mass causing rock mass oscillation. Investigations of the character and behavior of the pattern ...

  • Mogućnost infracrvene termografije pri detekciji štetnih gasova

    Stevan Đenadić, Vesna Damnjanović, Predrag Jovančić, Dragutin Jovković (2021)
    Curenje pojedinih gasova je opasnost koja može da izazove velike nezgode. Često je praćeno požarima i eksplozijama koji za posledicu mogu da imaju kako ljudske povrede, tako i štetan uticaj na ekologiju i ekonomiju. Da bi se izbegle takve situacije, preventivna inspekcija je od presudne važnosti. Curenje većine gasova se ne može uočiti golim okom a za otkrivanje i procenu stepena curenja može se koristiti tehnologija toplotnog snimanja (infracrvena termografija). U datom radu predstavljene su mogućnosti i ograničenja primene ...
    IC termografija, curenje gasa, termogram

  • A business intelligence approach to mine safety management

    Ljiljana Kolonja, Ranka Stanković, Ivan Obradović, Olivera Kitanović, Dejan Stevanović, Marija Radojičić (2016)
    ... n and analysis. The number of injuries, which represents a measure, is the central value of the cube that is analyzed. In our system, dimensions that are structural attributes of the cube, grouping data of similar category, are: type of injury, body part, severity of injury, worker’s age and q ...
    ... most important parts are the classification of external causes of injury, injury severity assessment and specification of part or parts of the body that were injured. 3.2 Methodology for data analysis Online analytical processing is a capability of management, decision support and executive ...
    ... quarter of the year, then by month, by date and finally selected injury levels. Figure 8 presents the number of injuries by quarter of the year, then by month, with severity of the injury, in tabular and graphical format, thus combining the time dimension (with its hierarchy) and injury severity. ...

  • Regional Slope Stability Analysis in Landslide Hazard Assessment Context, North Macedonia Example

    Miloš Marjanović, Biljana Abolmasov, Igor Peshevski, James Reeves, Irena Georgievska (2020)

  • Selection of Artificial Lift Methods: A Brief Review and New Model Based on Fuzzy Logic

    Miroslav Crnogorac, Miloš Tanasijević, Dušan Danilović, Vesna Karović Maričić, Branko Leković (2020)
    Artificial lift methods have applications in oil wells where oil production is no longer possible due to natural reservoir energy, so this necessary energy is added by introducing lift methods. In order to achieve optimum production, the selection of an artificial lift method is very important. This paper uses fuzzy logic as a mathematical and conceptual model for selection of the optimal artificial lift method. The outcome or IF-THEN rules, as the central part of the model, is based ...
    mehaničke metode, proizvodnja nafte, fazi logika, donošenje odluka, optimizacija
    ... prioritization of failures in a system failure mode, effects and criticality analysis. Reliab. Eng. Syst. Saf. 1995, 50, 203–213. [CrossRef] 29. Petrović, D.V.; Tanasijević, M.; Milić, V.; Lilić, N.; Stojadinović, S.; Svrkota, I. Risk assessment model of mining equipment failure based on fuzzy ...
    ... shows the conceptual model of an expert system for optimized selection of an artificial lift method evaluation on the base of fuzzy interferences of the input data. Energies 2020, 13, 1758 5 of 15 Energies 2020, 13, x 5 of 15 Figure 1. The schematic diagram of the fuzzy model. Parameters ...
    ... center of gravity moves to the right. When the parameters are reduced, the center of gravity moves to the left of the diagram. The uneven shift of the focus to the left side of the diagram is due to a considerable number of parameters being at the limit values (1 or 10). Figure 7. Center of mass ...

  • Uporedna analiza stabilnosti završnih kosina površinskog kopa „Veliki Krivelj“

    Mihajlo Topalović (2023)
    Površinski kop „Veliki Krivelj“ nalazi se u blizina grada Bora i u neposrednoj blizini sela Krivelj. Od 2018. godine je u vlasništvu kineske kompanije „Zijin“ koja ima udeo od 63% vlasništva celokupnog RTB-a Bor. Na površinskom kopu obavlja se masovna eksploatacija rude bakra opremom visokog kapaciteta. Za bušenje se koriste bušilice prečnika od 250 do 310 mm, a za utovar minirane rude i jalovine bageri čija je zapremina kašike 15 m3 i 22 m3. Za površinski kop „Veliki Krivelj“ ...
    stabilnost kosina, metoda konačnih elemenata, površinski kop, Veliki Krivelj, završna kosina

  • Метода променљивих околина за решавање проблема p-центра са поузданом мрежом

    Јована Рађеновић, Стефан Мишковић, Оливера Станчић (2023)
    У овом раду је разматран проблем p-центра са поузданом мрежом (енгл. Reliable p-center facility location problem - RpCFLP). Решавање проблема подразумева иницијално успостављање p ресурса и алокације корисника, као и накнадну реалокацију корисника у складу са новонасталим сценаријима који садрже информације о онеспособљеним ресурсима и осталим измењеним улазним подацима. За решавање посматраног проблема предложена је метахеуристика заснована на итеративној варијанти основне методе променљивих околина (енгл. Iterated basic variable neighborhood search - IBVNS). Резултати тестирања предложене метахеуристике указују на њену ...
    Проблем p-центра, Робусна оптимизација, Метода променљивих околина

  • Application of machine learning for diagnosing the operation of a deep well pump in oil production

    Maja Trikić (2024)
    This paper will thoroughly examine how machine learning can improve the diagnosis of deep well pumps by analyzing the role and function of the pumps, dynamograms, sensor technologies, and diagnostic methods.Our analysis will provide insights into modern techniques and approaches for enhancing the performance and reliability of oil production systems, targeting cost reduction and increased operational efficiency.
    deep well pump, dynamograms, machine learning, diagnostics of operating coditions,Random Forest, XGBoost
    ... identify patterns indicating the onset of a failure. 2.Temperature Sensors: Monitoring the temperature of pump components can help identify overheating, which may be an indicator of a fault or improper operation. 65 Temperature is a critical indicator of pump condition and can help prevent severe ...
    ... stoppages and thus result in losses, it is crucial to maximize the precision of the model. Conversely, if there is a higher risk of the model failing to detect a failure (false 47 negatives), achieving a high level of recall is critical. It is important to use metrics that combine precision and ...
    ... The Digital repository of The University of Belgrade Faculty of Mining and Geology archives faculty publications available in open access, as well as the employees' publications. - The Repository is available at: www.dr.rgf.bg.ac.rs University of Belgrade Faculty of Mining and Geology Master ...

  • 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