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367 items

  • A WebGIS Decision Support System for Management of Abandoned Mines

    Ranka Stanković, Nikola Vulović, Nikola Lilić, Ivan Obradović, Radule Tošović, Milica Pešić-Georgiadis (2016)
    ... mines with depleted reserves. Mines from the first group are especially interesting as objects for analysis when there is entrepreneurial and economic interest in their reactivation and evaluation of remaining reserves. As for those from the second group, they are of interest only as sites for remediation ...
    ... reclamation. Regardless of the group and the state of reserves, data collection is needed, as well as their systematization and representation in appropriate databases. From the legislative and legal point of view two subgroups can be distinguished within the first group, namely: (a) abandoned mines ...
    ... technological factors. Furthermore, each group of criteria was divided into individual criteria, and marks from 0 to 100 were assigned to each criterion, where 100 marks the highest and 0 the lowest priority for remediation. For the environmental protection group, the following factors were selected ...

  • 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
    ... three groups (Table 1): Table 1. Group of parameters by selection method. Selection Method First Group Second Group Third Group Neely [6] x x Valentin [7] x x x Clegg [8] x x x 1 Espin [9] x 1 x 1 x Heinze [10] x x x Alemi [11–14] x x 1 priority. The first group (I) represents methods that use ...
    ... takes into account economic aspects (costs) [7]. In 1994, Espin and a group of authors observed technical characteristics and then economic ones [9]. In 1995, Heinze and a group of authors use the decision tree to apply group criteria in several steps. The first two steps used technical constraints ...
    ... secondary technical limitations, such as temperature limitations, operator training, availability of the main source of energy, fluid, surface conditions (space limitations, noise, visibility, safety), and additional limitations at the bottom of the well (high gas-liquid ratio—GLR, scale, sand, corrosion) ...

  • Development of a petrographic classification system for organic particles affected by self-heating in coal waste. (An ICCP Classification System, Self-heating Working Group – Commission III)

    M. Misz-Kennan, J. Kus, D. Flores, C. Avila, Z. Büçkün, N. Choudhury, K. Christanis, J.P. Joubert, S. Kalaitzidis, A.I. Karayigit, M. Malecha, M. Marques, P. Martizzi, J.M.K. O'Keefe, W. Pickel, G. Predeanu, S. Pusz, J. Ribeiro, S. Rodrigues, A.K. Singh, I. Suárez-Ruiz, I. Sýkorová, N.J. Wagner, D. Životić (2020)
    Self-heating of coal waste is a major problem in the leading coal-producing and consuming countries, independent of the recent or past coal exploitation history. The phenomenon of self-heating is dependent on many factors such as the properties of organic matter (maceral composition and rank), moisture and pyrite content, climate effects, and storage conditions (shape of the dump or compaction of the coal waste). Once deposited, coal waste undergoes oxidation, which can lead to self- heating with the overall temperatures ...
    Stratigraphy,Economic Geology,Geology,Fuel Technology

  • GIS Application Improvement with Multilingual Lexical and Terminological Resources

    Ranka Stanković, Ivan Obradović, Olivera Kitanović (2010)
    ... paper introduces the results of integration of lexical and terminological resources, most of them developed within the Human Language Technology (HLT) Group at the University of Belgrade, with the Geological information system of Serbia (GeolISS) developed at the Faculty of Mining and Geology and funded ...
    ... this paper is based on an integration of lexical and terminological resources, most of them developed within the Human Language Technology (HLT) Group at the University of Belgrade, and the Geological information system of Serbia (GeolISS), developed at the Faculty of Mining and Geology and ...
    ... and geophysical analysis, different types of measurements, stratigraphic age, lithology, etc. 3. Lexical and Terminological Resources The HLT Group has been developing various lexical resources over a long period, and they have reached a considerable volume to date (Vitas et al., 2003). They ...

  • Polymorphism and photoluminescence properties of K3ErSi2O7

    Predrag Dabić, Marko G. Nikolić, Sabina Kovač, Aleksandar Kremenović (2019)
    alkalni silikati elemenata retkih zemalja, silikati lantanoida, polimorfizam, fotoluminescencija, kristalna struktura

  • Sinteza i strukturna karakterizacija novih cezijumskih i kalijumskih silikata sa elementima retkih zemalja

    Predrag Z. Dabić (2022)
    Predmet i ciljevi naučnog istraživanja ove doktorske disertacije su sinteza i strukturna karakterizacija novih cezijumskih i kalijumskih silikata sa elementima retkih zemalja. Istraživanja su izvedena u okviru sistema SiO2–REE2O3–XF, gde REE predstavlja trovalentni katjon elementa retkih zemalja (Sc, Y, Sm, Eu, Gd, Ho, Er, Tm, Yb, Lu), dok X predstavlja jednovalentni katjon alkalnih metala (K, Cs). Rad na disertaciji bio je fokusiran na sintezu monokristala, određivanje kristalnih struktura, kao i na kristalografsko i kristalohemijsko ispitivanje sintetisanih monokristala. Monokristali su sintetisani ...
    alkalni silikati elemenata retkih zemalja, kristalna struktura, sinteza metodom fluksa, rendgenska difrakcija na monokristalu, elementi retkih zemalja

  • Open Educational Resources in Serbia

    Ivan Obradović, Ranka Stanković, Marija Blagojević, Danijela Milošević (2020)
    Open educational resources, BAEKTEL, Metadata portal
    ... skills while developing or using OERs. Teachers usually develop OERs bearing in mind a specific target group. But, an OER is always “open”, so the content finds another interested target group beside the initially planned. This kind of OERs for specific target groups are sometimes inadequate or ...
    ... about open education resources. The aim of the portal of the Open Education Initiative is to contribute to the inclusion of Serbia’s educational space in European and global trends in open education. Several university teachers have already made their learning materials freely available on this ...
    ... mention of them in the Law on Higher Education, although there are some references to openness and harmonization with the European educational space. Namely, among the goals of higher education, Article 3, Item 7, states “improvement of the international openness of the higher education system” ...

  • 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
    ... during tunnel construction. In Underground Space—The 4th Dimension of Metropolises, Proceedings of the 33rd ITA-AITES World Tunnel Congress; Prague, Czech Republic, 5–10 May 2007, Barták, J., Hrdina, I., Romancov, G., Zlámal, J., Eds.; Taylor & Francis Group: London, UK, 2007; pp. 857–862. 10. Merlini ...
    ... summing the matrices within each group. The split of the set of indices {1, . . . , Lsum} into disjointed subsets I1, . . . , Ik corresponds to the representation of YV = YI1 + . . . + YIk . The procedure of choosing the sets I1, . . . , Ik is called grouping. For a given group I, the contribution of the component ...
    ... and summing the matrices within each group. The split of the set of indices {1,...,Lsum} into disjointed subsets I;,..., [, corresponds to the representation of Yy = Y;, +... + Y;,. The procedure of choosing the sets I1,..., I, is called grouping. For a given group I, the contribution of the component ...

  • 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
    ... tool TPOT. The metric values (accuracy, F1 macro, and MCC) for this group are shown in Figure 6.12. Group B 036 04516 —— []],7] Loads + AML Fourier + AML MmAccuracy BFIMacro = MCC Figure 6.12 Metrics for Group B In Group C, all classes had 90 samples in the training set. Tests were conducted ...
    ... Figure 6.11. All charts in the following sections are normalized. Group A Loads + XgB+ - Foomer [7% Fowner+XgB Wavelet+ - Wavelet+ - Wavele NoTu m Accuracy MFIMacro m MCC Figure 6.11 Metrics Jor Group A 62 In Group B, all classes had 30 samples in the training set. Tests were conducted ...
    ... 13 Metrics for Group C 63 In Group D, all classes had 180 samples in the training set. Tests were conducted using all descriptors (Fourier, wavelet, and load) and only one algorithm (decision tree). Figure 6.14 shows the metric results (accuracy, FI macro, and MCC) for this group. The goal of ...

  • Hydrochemical changes and groundwater grouping data by multivariate statistical methods within one karst system: recharge–discharge zone (Eastern Serbia case study)

    Ljiljana Vasić, Dragana Živojinović, Vladana Rajaković-Ognjanović (2020)
    Geochemistry and Petrology

  • Demise of the Wetterstein Carbonate Platform and onset of the Dachstein Carbonate Platform recorded in deep-water successions of the East Bosnian-Durmitor megaunit (Pliješevina, northern Montenegro, Dinarides)

    Milica Mrdak, Eva Wagerer, Milan Sudar, Nevenka Djerić, Martin Đaković, Hans-Jürgen Gawlick (2024)
    Triassic, Carnica event, clay mineralogy, conodont biostratigraphy, Neo-Tethys

  • Development of Open Educational Resources (OER) for Natural Language Processing

    Cvetana Krstev, Biljana Lazić, Ranka Stanković, Giovanni Schiuma, Miladin Kotorčević (2015)
    In this paper we present the development of an online course at the edX BAEKTEL platform named “Lexical Recognition in the Natural Language Processing (NLP)”. It is based on the course of the same name for PhD studies at the University of Belgrade, Faculty of Philology. There are not many courses in Computational Linguistics (CL) on OER platforms, and there is none in Serbian either for CL or NLP. We have developed this course in order to improve this ...
    E-Learning, Open Educational Resources, Computational Linguistics, Lexical Resources, edX
    ... Technologies (HLT) group that gathered researchers of diffеrent background from several faculties of the University of Belgrade. Also, a number of PhD theses and master theses have been completed in this field and several are in their final phase. The participation of the HLT group in several ...
    ... criteria [15]:  adjusting the content to the target group,  systematization and gradualism in the teaching process,  connecting the theory and the practice. To satisfy the first criterion of adjusting the content to the target group, we provided a description of the course, a list of ...
    ... years ago when Professor Duško Vitas initiated the interest in CL as a research field in Serbia, broadened its influence, and established the group of interested researchers. The first courses at University of Belgrade were introduced in 1994: in Mathematical and CL for students of General ...

  • Contribution to the geotechnical classification of municipal waste landfills in Serbia

    Dragoslav Rakić, Irena Basarić, Laslo Čaki, Slobodan Ćorić (2018)
    Management, Monitoring, Policy and Law, Nature and Landscape Conservation, Geochemistry and Petrology, Waste Management and Disposal,Geotechnical Engineering and Engineering Geology,Water Science and Technology,Environmental Chemistry,Environmental Engineering

  • FTIR Spectroscopic Study Of S-Metolachlor Sorption On Inorganic And Organically Modified Montmorillonite From Bogovina

    Lazar Kaluđerović, Zorica Tomić, Jelena Bogosavljević, Ljubomir Životić, Maja Milošević (2021)
    ... that carbonyl group participate in the binding process. Sorption of S-metolachlor on HDTMA-montmorillonites causes the redshift of the C = O absorption band. Shifting to lower wavenumbers and joining with the deformation vibration band of water indicates that the C = O group participated in ...
    ... llonite) are typical for smectites with a high Al content in the octahedron position. The intercalation of HDTMA+ cations into the interlayer space produces redshift of the IR bands that originate from the vibrations of the adsorbed water, as a consequence of the reduction of the hydrogen bond ...
    ... significantly with increasing concentration of HDTMA+ cation. All these changes are related to the decreasing of the water content in the interlayer space by increasing the content of HDTMA. The occurrence of the stretching CH2 vibrations is generally the main difference in the spectrum of HDTMA modified ...

  • Paleomagnetic evidence for CW rotation in the Western Vardar zone of Serbia

    Lesić Vesna, Márton Emo, Cvetkov Vesna, Gajić Violeta, Jovanović Dragana (2017)

  • Hydrogeochemical pathways of the karst-fissured aquifer system, Pirot (Serbia)

    Marina Ćuk, Igor Jemcov, Maja Todorović, Ana Mladenović (2019)

  • Understanding and Importance of Rare Earth Elements in Hydrogeological Systems

    Maja Todorović, Marina Ćuk, Jana Štrbački, Petar Papić, Igor Jemcov (2018)

  • Prognozna ocena resursa kaolinitskih glina u sedimentnim basenima Srbije

    Vladimir M. Simić (2003)
    Kaolinitske gline predstavljaju jednu od privredno najznačajnijih nemetaličnih mineralnih sirovina u Srbiji. Ležišta tih glina odavno se istražuju i eksploatišu u Aranđelovačkom i Kolubarskom basenu i basenima vlašićkog antiklinorijuma. Osim toga, u većem ili manjem obimu istražene su mnoge lokalnosti, a na nekima od njih vršila se povremena eksploatacija. Dosadašnja istraživanja kaolinitskih glina imala su, međutim, prevashodno uzak istraživački cilj - utvrđivanje rezervi glina određenog ležišta, dok su istraživanja regionalnog karaktera bila malog obima i vezana za delove pojedinih ...
    prognozna ocena, resursi kaolinitskih glina, sedimentni baseni, Srbija, geologija, mineralogija, kvalitet, potencijalnost

  • A WordNet Ontology in Improving Searches of Digital Dialect Dictionary

    Miljana Mladenović, Ranka Stanković, Cvetana Krstev (2017)
    In this paper, we present a method for automatic generation of a digital resource, which connects all indirect synonyms of a dialect term to all indirect synonyms of a corresponding term in the standard language, aiming to improve the search of a digital dialect dictionary. The method uses SWRL rules defined in the Serbian WordNet ontology to identify sets of synonymous words. It also uses e-dictionaries to produce correct lemmas in standard language that users usually employ in searches. ...
    ... e-dictionaries to produce correct lemmas in the standard language that users usually use for search. The method was applied and evaluated on verbs and a group of nouns derived from verbs (verbal nouns). We compared results obtained by the system with those produced by humans and achieved the accuracy of 89 ...
    ... synonyms of a dialect term to all indirect synonyms of a corresponding term in the standard language. In Section 5 the method is evaluated on verbs and a group of nouns derived from verbs — verbal nouns. Finally, we give some conclusions and directives for future work in Section 6. 2 The management of digital ...
    ... lemmatization task we used Serbian morphological electronic dictionaries and grammars developed within the University of Belgrade Human Language Technology Group [14]. Morphological electronic dictionaries of Serbian for NLP are being developed for many years now. In the dictionary of lemmas (DELAS) each lemma ...

  • Multi-word Expressions for Abusive Speech Detection in Serbian

    Ranka Stanković, Jelena Mitrović, Danka Jokić, Cvetana Krstev (2020)
    Ovaj rad predstavlja istraživanja na usavršavanju i unapređenju srpske verzije rečnika Hurtlex, višejezičnog leksikona uvredljivih reči. Posebnu pažnju posvećujemo dodavanju izraza sa više reči (polileksemskih jedinica) koji se mogu smatrati uvredljivim, jer su takvi leksički zapisi veoma važni za postizanje dobrih rezultata u mnoštvu zadataka otkrivanja uvredljivog jezika. Srpski morfološki rečnici se koriste kao osnova za čišćenje podataka i stvaranje rečnika. Istaknuta je veza sa drugim leksičkim i semantičkim resursima na srpskom jeziku i predviđena je izgradnja sistema za ...
    uvredljiv govor, govor mržnje, leksički izvori, višejezični leksikon, izrazi sa više reči
    ... Among the group of verbal expressions the most frequent are those with a structure V N (289), followed by V PREP N (124), V PRO N (52), V N PREP N (40). Again, this is a rough analysis because each group may contain syn- tactically very different expressions. For instance, the V N group contains besides ...
    ... collocations, colloquial expressions, and context. Starting from the definition of hate speech as ‘any communication that disparages a person or a group on the basis of some characteristic such as race, color, ethnicity, gender, sexual orientation, nationality, religion, or other characteristic’ (Nockleby ...
    ... attention recently. Caselli et al. (2020) define abusive language as ‘hurtful language that a speaker uses to insult or offend another individual or a group of individuals based on their personal qualities, appearance, social status, opinions, statements, or actions. This might include hate speech, derogatory ...