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486 items
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A fuzzy-based decision support model for effectiveness evaluation - a case study of examination of bulldozers
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 ...Miloš Tanasijević, Predrag Jovančić, Dejan Ivezić, Uglješa Bugarić, Radiša Đurić. "A fuzzy-based decision support model for effectiveness evaluation - a case study of examination of bulldozers" in International Journal of Industrial Engineering: Theory, Applications and Practice (2019)
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Climate change and their imapct on karst groundwater
Milan Đelić, Vesna Ristić Vakanjac (2021)In the last 30 years, there have been progressively more dry and rainy years, a reduced presence or even absence of snow cover, an increase in air temperature, large-scale fires, intensified glacier melting, and the like. Climate change certainly has an effect on all areas of economic activity, but its largest impact is on water resources and existing ecosystems. One of the most important water resources is groundwater, on account of which more than 70% of the population of ...Milan Đelić, Vesna Ristić Vakanjac . "Climate change and their imapct on karst groundwater" in Book of proceedings of the 3rd International Scientific Conference on vircular and bioeconomy CIBEK2021, Belgrade, Belgrade : School of Engineering Management (2021)
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A Fuzzy Expert Model for Availability Evaluation
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 ...... 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 interference of reliability (R) ...
... based on experts’ opinions. Fig. 1. The fuzzy model for availability evaluation The mathematical and conceptual model of availability assessment is practically summarized in two steps: fuzzy proposition of availability partial indicators - R, M and S and fuzzy composition of mentioned indicators ...
... indicators into one A. The defining of linguistic variables for A, R, M and S is the first step in the creation of an expert model for A- assessment. This approach creates an environment for the fuzzy inference engine. Fuzzy sets are in triangular form and these are shown in figure 2, in relation ...Dejan Ivezić, Miloš Tanasijević, Predrag Jovančić, Radiša Đurić. "A Fuzzy Expert Model for Availability Evaluation" in Proceedings of the 2019 20th International Carpathian Control Conference (ICCC), AGH University of Science and Technology, Kraków - Wieliczka, Poland (2019)
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Effects of bentonite binder dosage on the properties of green limestone pellets
Vladimir Jovanović, Dinko Knežević, Živko Sekulić, Milan Kragović, Jovica Stojanović, Slavica Mihajlović, Dragana Nišić, Dragan Radulović, Branislav Ivošević, Milan Petrov (2016)This paper presents the results of tests carried out to determine how the dosage of bentonite added as binder, affects the properties of green pellets made of the limestone fines that originate from Lithothamnium limestone processing. Bentonite was added to limestone in different mass fractions (1, 2.5, 5 and 10%), whereas all the other parameters of the pelletizing process remained constant. The aim of pelletizing was to consolidate limestone fines and form mechanically stable pellets, provided that all the ...Vladimir Jovanović, Dinko Knežević, Živko Sekulić, Milan Kragović, Jovica Stojanović, Slavica Mihajlović, Dragana Nišić, Dragan Radulović, Branislav Ivošević, Milan Petrov. "Effects of bentonite binder dosage on the properties of green limestone pellets" in Chemical Industry, Beograd : National Library of Serbia (2016). https://doi.org/10.2298/HEMIND160210023J
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Machine learning based landslide assessment of the Belgrade metropolitan area: Pixel resolution effects and a cross-scaling concept
Improvements of Machine Learning-based landslide prediction models can be made by optimizing scale, customizing training samples to provide sets with the best examples, feature selection, etc. Herein, a novel approach, named Cross-Scaling, is proposed that includes the mixing of training and testing set resolutions. Hypothetically, training on a coarser resolution dataset and testing the model on a finer resolution should help the algorithm to better generalize ambiguous examples of landslide classes and yield fewer over/underestimations in the model. This ...Uroš Đurić, Miloš Marjanović, Zoran Radić, Biljana Abolmasov. " Machine learning based landslide assessment of the Belgrade metropolitan area: Pixel resolution effects and a cross-scaling concept" in Engineering Geology , Elsevier (2019). https://doi.org/10.1016/j.enggeo.2019.05.007
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Hydrochemical features and their controlling factors in the Kucaj-Beljanica Massif, Serbia
Earth-Surface Processes, Geology, Pollution, Soil Science, Water Science and Technology, Environmental Chemistry, Global and Planetary ChangeFen Huang, Ljiljana Vasic, Xia Wu, Jianhua Cao, Saša Milanovic. "Hydrochemical features and their controlling factors in the Kucaj-Beljanica Massif, Serbia" in Environmental Earth Sciences, Springer Science and Business Media LLC (2019). https://doi.org/10.1007/s12665-019-8452-4
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Design of the Opencast Coal Mine Drmno Dewatering System
Development of mining in the opencast mine Drmno from Kostolac basin in Serbia is carried out in the increasingly complex geological and hydro geological conditions with the decline of the coal seams to the alluvial part of Europe's largest river Danube. Greater depth and inflow of groundwater significantly increase costs for dewatering facilities construction with the requirement for optimizing of this more and more important surface mining process. Making decision on screen construction in the opencast mine with redesign ...dewatering system, groundwater, hydrodynamic model, dewatering wells, screen, reliability, environmental effects.Vladimir Pavlović, Dušan Polomčić, Tomislav Šubaranović. "Design of the Opencast Coal Mine Drmno Dewatering System" in Proceedings of the 12th International Symposium Continuous Surface Mining - Aachen 2014, Springer International Publishing (2014). https://doi.org/10.1007/978-3-319-12301-1_11
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The Importance of Detailed Groundwater Monitoring for Underground Structure in Karst (Case Study: HPP Pirot, Southeastern Serbia)
... tests; groundwater aggressiveness; tunnel vulnerability 1. Introduction The presence of an underground structure in a karst can have a considerable impact on the natural status of groundwater and, conversely, the groundwater can affect the structure (the two are in constant interaction). In general, karst ...
... tests; groundwater aggressiveness; tunnel vulnerability 1. Introduction The presence of an underground structure in a karst can have a considerable impact on the natural status of groundwater and, conversely, the groundwater can affect the structure (the two are in constant interaction). In general, karst ...
... water losses from the tunnel showed that they were relatively acceptable and that their distribution along the tunnel was not uniform. The closer assessment of the zone with the highest water losses pointed to the part of the tunnel where the concrete lining was unstable. Comprehensive tunnel investigations ...Marina Čokorilo Ilić, Ana Mladenović, Marina Ćuk, Igor Jemcov. "The Importance of Detailed Groundwater Monitoring for Underground Structure in Karst (Case Study: HPP Pirot, Southeastern Serbia)" in Water, MDPI AG (2019). https://doi.org/10.3390/w11030603
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Contents of potentially toxic elements in residual soils of a long-term mining region: a key study from Central and Western Serbia
Milun Jovanović, Dejan Prelević, Vidojko Jović, Danica Srećković-Batoćanin, Snežana Branković (2022)Regional geochemical research of residual soil was conducted in an area of about 20,000 km2 in the region of Central and Western Serbia, where six metallogenetic zones and mining since ancient times have been documented. The geochemical background variation in the residual soil was established upon the contents, spatial pattern and natural background of potentially toxic elements (PTEs). The limits of natural background values (mg·kg-1) were determined by the integral method. Our data show that anomalous concentrations of As, ...Milun Jovanović, Dejan Prelević, Vidojko Jović, Danica Srećković-Batoćanin, Snežana Branković. "Contents of potentially toxic elements in residual soils of a long-term mining region: a key study from Central and Western Serbia" in Periodico di Mineralogia (2022). https://doi.org/10.13133/2239-1002/17042
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Mikroelementi u kvartarnim sedimentima i lignitu Kostolačko-kovinskog ugljonosnog basena, istočna Srbija – odabrani primeri
Sadržaj, distribucija i način pojavljivanja elemenata u tragovima (mikroelemenata), posebno potencijalno toksičnih i radioaktivnih elemenata u uglju, su od velikog značaja, posebno ako se koriste kao gorivo u termoelektranama (TE). Na osnovu sistematski prikupljenih podataka o elementima u tragovima u uglju, zemljištu i sedimentima, moguće je utvrditi stepen zagađenosti vazduha, zemljišta, vode, kao i negativan uticaj na zdravlje ljudi. Eksploatacija i istraživanje lignita u Kostolcu i Kovinu traje više od jednog veka, dok se sagorevanje lignita sa površinskih kopa ...Bogoljub Vučković, Biljana Radovanović, Dragana Životić. "Mikroelementi u kvartarnim sedimentima i lignitu Kostolačko-kovinskog ugljonosnog basena, istočna Srbija – odabrani primeri" in 18. Kongres geologa Srbije "Geologija rešava probleme", Divčibare, 01-04 jun 2022., Srpsko geološko društvo (2022)
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Advantages and challenges in presenting mathematical content using EDX platform
... improvement of educational and internet technologies has contributed to faster development of Open Educational Resources. OERs have had significant impact on lifelong learning and on the availability of learning content. Despite worldwide trends, in Serbia the idea of implementing OER materials in higher ...
... hints and feedbacks. The platform offers additional advanced options for task design like circuit schematics builder, image mapped input, peer assessment etc. These additional options require some basic programing in Python. All these types of task work with edX tags which annotate the type of ...Marija Radojičić, Ivan Obradović, Ranka Stanković, Olivera Kitanović, Roberto Linzalone. "Advantages and challenges in presenting mathematical content using EDX platform" in The Seventh International Conference on e-Learning (eLearning-2016), Belgrade : Metropolitan University (2016)
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Ocena zaštitne funkcije povlatnih slojeva izvorišta Jasik (Opština Batočina) primenom GLA metode
U cilju utvrđivanja rezervi podzemnih voda i analize uslova zaštite u periodu 2012. i 2013. godine, sprovedena su detaljna hidrogeološka istraživanja na području izvorišta Jasik (opština Batočina). Uspostavljen je sistem monitoringa, čiji je rezultat predstavljao prikupljanje detaljnih hidrogeoloških podataka. Za potrebe analize, izrađen je hidrodinamički model, na osnovu koga je simulirano kretanje podzemnih voda, odnosno, utvrđene zone sanitarne zaštite. Pored navedenog, za potrebe utvrđivanja uslova zaštite podzemnih voda, bilo je neophodno utvrditi podložnost aluvijalne izdani izvorišta Jasik zagađenju. Polazeći ...Rastko Petrović, Igor Jemcov, Dušan Polomčić. "Ocena zaštitne funkcije povlatnih slojeva izvorišta Jasik (Opština Batočina) primenom GLA metode" in Vodoprivreda, Srpsko društvo za navodnjavanje i odvodnjavanje (2014)
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Curcumin nanonization using an alternative small-scale production unit: selection of proper stabilizer applying basic physicochemical consideration and biological activity assessment of nanocrystals
Ines Nikolić, Jelena Antić-Stanković, Dragana Božić, Danijela Ranđelović, Bojan Marković, Dominique Jasmin Lunter, Aleksandar Kremenović, Miroslav Savić, Snežana Savić (2020)As the number of poorly soluble drugs is increasing, nanocrystals have become very interesting due to wide range of application possibilities. Curcumin was used as a model active ingredient in this work. Even though it has many proven positive effects, due to its physicochemical issues, its possibilities have not been fully exploited. The goal of this work was to select optimal conditions for a top-down method for curcumin nanosuspension production, and to perform their comprehensive characterization applying complementary methodologies: ...Ines Nikolić, Jelena Antić-Stanković, Dragana Božić, Danijela Ranđelović, Bojan Marković, Dominique Jasmin Lunter, Aleksandar Kremenović, Miroslav Savić, Snežana Savić. "Curcumin nanonization using an alternative small-scale production unit: selection of proper stabilizer applying basic physicochemical consideration and biological activity assessment of nanocrystals" in Review on advanced materials science, Walter de Gruyter GmbH (2020). https://doi.org/10.1515/rams-2020-0043
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Spatial distribution of major and trace elements in artificial lakes in Serbia: health risk indices and suitability of water for drinking and irrigation purposes
Goran Marković, Aleksandar Ž. Kostić, Nebojša Đ. Pantelić, Radojka Maletić, Jana Štrbački, Jovan Cakić, Lazar Kaluđerović, Biljana P. Dojčinović, Angelo Maria Giuffrè, Jelena B. Popović-Djordjević (2023)Lakes and reservoirs are the main water resources for household, irrigation, and industrial use. Hence, it is necessary to control water pollution and have reliable information on water quality, which refers to its suitability for a particular purpose. The main objective of this study was to evaluate the suitability of water for drinking and irrigation purposes from ten artificial lakes on the territory of the Republic of Serbia. The physicochemical parameters were determined using standard analytical methods, whereas the ...Goran Marković, Aleksandar Ž. Kostić, Nebojša Đ. Pantelić, Radojka Maletić, Jana Štrbački, Jovan Cakić, Lazar Kaluđerović, Biljana P. Dojčinović, Angelo Maria Giuffrè, Jelena B. Popović-Djordjević. "Spatial distribution of major and trace elements in artificial lakes in Serbia: health risk indices and suitability of water for drinking and irrigation purposes" in Environmental Monitoring and Assessment, Springer Science and Business Media LLC (2023). https://doi.org/10.1007/s10661-023-11740-6
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Refinement of waste phosphogypsum from Prahovo, Serbia: characterization and assessment of application in civil engineering
Josip Išek, Lazar Kaluđerović, Nikola Vuković, Maja Milošević, Ivana Vukašinović, Zorica Tomić (2020)... Измењено: 2023-11-06 09:42:47 Refinement of waste phosphogypsum from Prahovo, Serbia: characterization and assessment of application in civil engineering Josip Išek, Lazar Kaluđerović, Nikola Vuković, Maja Milošević, Ivana Vukašinović, Zorica Tomić Дигитални репозиторијум ...
... јум Рударско-геолошког факултета Универзитета у Београду [ДР РГФ] Refinement of waste phosphogypsum from Prahovo, Serbia: characterization and assessment of application in civil engineering | Josip Išek, Lazar Kaluđerović, Nikola Vuković, Maja Milošević, Ivana Vukašinović, Zorica Tomić | Clay Minerals ...
... doi:10.1180/cim.2020.11 Article GCAMBRIDGE UNIVERSITY PRESS Refinement of waste phosphogypsum from Prahovo, Serbia: characterization and assessment of application in civil engineering Josip l. Išekt, Lazar M. Kaluđerović** ', Nikola S. Vuković3, Maja Milošević1, Ivana Vukašinović? and Zorica ...Josip Išek, Lazar Kaluđerović, Nikola Vuković, Maja Milošević, Ivana Vukašinović, Zorica Tomić. "Refinement of waste phosphogypsum from Prahovo, Serbia: characterization and assessment of application in civil engineering" in Clay Minerals, Cambridge University press (2020). https://doi.org/10.1180/clm.2020.11
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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... is the percentage of the most frequent class in the dataset. In this study, the class of fluid impact logs has the highest number of samples (76%). If an algorithm classifies all logs as fluid impact logs, it could still be considered acceptable. It is also important to investigate where the algorithm ...
... algorithm fails using confusion matrices. In this problem, errors often involve fluid impact logs and gas interference. Setting a maximum threshold for fluid impact logs may be beneficial. After implementation, it is recommended that the classifier provides probabilities for different types rather ...
... clusters, helping to identify normal and anomalous patterns in pump operation. b.DBSCAN (Density-Based Spatial Clustering of Applications with Noise) - Identifies dense areas of data and anomalies, which can help in finding unusual conditions. 25 c.Autoencoders – Used for reconstructing input ...Maja Trikić. Application of machine learning for diagnosing the operation of a deep well pump in oil production, 2024
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A survey of greenhouse gases production in central European lignites
Anna Pytlak, Anna Szafranek-Nakonieczna, Weronika Goraj, Izabela Śnieżyńska, Aleksandra Krążała, Artur Banach, Ivica Ristović, Mirosław Słowakiewicz, Zofia Stępniewska (2021)... cially the atmosphere. Air pollution generated by the mining industry has both a local (particulate matter, sulphur and nitrogen oxides) and a global impact (greenhouse gases, GHG). GHG emissions are of partic- ular concern because coal mining and burning comprise a high propor- tion of the anthropogenic ...
... the results presented by Liu et al. (2020) who pointed out that rewetting of the peatlands ef- fectively reduces N2O emissions. 3.4. Environmental impact of flooded lignites Results concerning GHG production by flooded lignites suggest that they would mainly release CO2. Methane emissions were significantly ...
... the oxidation of sulphides (Gläßer et al., 2011). At low pH, the water solu- bility of CO2 decreases substantially, thus, water chemistry has a huge impact on the buffering of lignite-originating CO2 emissions. Lake eco- systems are also a habitat of methanotrophic bacteria, whichmay effec- tively reduce ...Anna Pytlak, Anna Szafranek-Nakonieczna, Weronika Goraj, Izabela Śnieżyńska, Aleksandra Krążała, Artur Banach, Ivica Ristović, Mirosław Słowakiewicz, Zofia Stępniewska. "A survey of greenhouse gases production in central European lignites" in Science of The Total Environment, Elsevier (2021). https://doi.org/10.1016/j.scitotenv.2021.149551
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Effects of external noise on threshold-induced correlations in ferromagnetic systems
Dragutin Jovković, Sanja Janićević, Svetislav Mijatović, Lasse Laurson, Đorđe Spasojević. "Effects of external noise on threshold-induced correlations in ferromagnetic systems" in Physical Review E, American Physical Society (APS) (2021). https://doi.org/10.1103/PhysRevE.103.062114
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Потреба за израдом биланса и оценом расположивих резерви подземних вода Републике Србије
Природне карактеристике Србије, просторна дистрибуција ресурса водe и њихових корисника, као и међусобна интеракција коришћења, заштите вода, као и заштите од вода, условиле су да се подземне воде на читавој територији морају посматрати интегрално, јединствено, комплексно и рационално. Међутим, тренутно је у Републици Србији могуће дефинисати само одлике појединих издани и/или изворишта услед непостојања довољних података за свеобухватну анализу стања ресурса. За оцену притиска на квантитет ресурса подземних вода, што је обавеза према Оквирној директиви о водама ЕУ (ОДВ) ...Зоран Стевановић, Вељко Мариновић, Бранислав Петровић. "Потреба за израдом биланса и оценом расположивих резерви подземних вода Републике Србије" in Записници Српског геолошког друштва, Српско геолошко друштво (2021)
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Formative evaluation of e-learning projects with the logical framework approach
... associated, with scientific criterion, of a project (evaluand). The purposes of the evaluation of an e-learning project are different: to determine the impact on beneficiaries' performance, to compare projects, to support the improvement of projects in terms of socio-economic effects and impacts, on individuals ...
... associated, with scientific criterion, of a project (evaluand). The purposes of the evaluation of an e- learning project are different: to determine the impact on beneficiaries' performance, to compare projects, to support the improvement of projects in terms of socio- economic effects and impacts, on ...
... beneficiaries, companies, processes, etc.). Outcomes reveal in the short-term (from 1 to 3 years), or in the long- term (over a period of 4 to 6 years). Impact is the fundamental change, wanted or not wanted, intended or unintended, that occurs in organizations, communities, or systems as a result of ...Roberto Linzalone, Giovani Schiuma, Ivan Obradović, Ranka Stanković. "Formative evaluation of e-learning projects with the logical framework approach" in The Sixth International Conference on e-Learning (eLearning-2015), September 2015, Belgrade, Serbia, Belgrade Metropolitan Univesity (2015)