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Упит dcterms_subject_txt:Economics and Econometrics

2341 items

  • Threshold-induced correlations in the Random Field Ising Model

    Sanja Janićević, Dragutin Jovković, Lasse Laurson, Đorđe Spasojević (2018)
    Multidisciplinary
    ... size S and duration T of a subavalanche (starting at the moment ts and ending at te = ts + T) taken out of the avalanche i, the internal waiting time Tint between two subavalanches of avalanche j, and the contributions Tend, Tmid, and Tini to the external waiting time Text between avalanches i and j, see ...
    ... 1024 and 40 random field configurations for each disorder R. (a) For a (blue) part of a train of avalanches (shown in bottom, and zoomed in top panel) and the imposed threshold V,, (red line), we illustrate: the determination of size S and duration T of a subavalanche (starting at the moment f, and ending ...
    ... appropriate normalization constant, and analogously for other similar distributions DS(S; Vth, λ) and λD T V( ; , )T int thint for size S and internal waiting time Tint, as well as for the distributions λD T V( ; , )T end thend and λD T V( ; , )T ini thini of Tend and Tini. Now, let us suppose that ...

  • Prioritization of strategic measures for strengthening the security of supply of the Serbian natural gas sector

    Boban Pavlović, Dejan Ivezić, Marija Živković (2020)
    To strengthen the security of supply of the Serbian gas sector, it is necessary to analyze the impact of planned strategic measures. The analysis involves the identification of the most influential threats to the security of natural gas supply and prioritization of the strategic measures for overcoming the consequences of threats. The proposed methodology is based on Fuzzy Analytic Hierarchy Process. The obtained weights for the identified threats and strategic measures are formed according to experts' judgments. The results ...
    Sigurnost snabdevanja, Donošenje odluka, Snabdevanje prirodnim gasom, Fazi AHP, Energetski indikatori

  • 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)
    Lignit, Gasovi sa efektom staklene bašte, Ugljen dioksid, Metan, Azotni oksid
    ... half of all lignite is mined and utilized in Europe (Knoema, 2020). The extraction and combustion of coal pollutes water, soil, and espe- 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 ...
    ... deposits exploited in Poland, Slovenia and Serbia, which represent various lithotypes, ages and burial histories. GHG production was studied along with a range of physical and chemical parameters that are crucial for microbial growth and activity. 2. Materials and methods 2.1. Sampling sites Lignites ...
    ... (Zechstein) evaporites. Palaeogene and Neogene filling of the graben is underlain by Upper Jurassic limestones and Upper Cre- taceous gaizes. The productive coal complex is considered to be an equivalent of ŚLS-3 (in the lower part) and LLS-2 (in the upper part) (Pawelec and Bielowicz, 2016; Widera, 2016b) ...

  • Frequency and Length of Syllables in Serbian

    Marija Radojičić, Biljana Lazić, Sebastijan Kaplar, Ranka Stanković, Ivan Obradović, Ján Mačutek, Lívia Leššová (2019)
    Basic analyses of several properties of syllables (the rank-frequency distribution, the distribution of length, and the relation between length and frequency) in Serbian is presented. The syllabification algorithm used combines the maximum onset principle and the sonority hierarchy. Results indicate that syllables behave similarly to words as far as mathematical models are concerned, but values of parameters in models for syllables are quite different from those for words.
    frekvencije slogova, dužina slogova, srpski jezik
    ... (2008). Frequency and Length of Syllables in Serbian 117 3. Language material Serbian is a South Slavic language. It has the official status in Serbia (exclusively) and in Bosnia and Herzegovina (as one of three languages, together with Bosnian and Croatian), and the status of a minority ...
    ... distinguishing between marginal (rarely occurring and considered to be exceptions) and non-marginal (found with a high frequency) consonant clusters at beginnings and ends of words; only those which are not marginal are allowed to form syllable onsets and codas. If one follows his modification, a large ...
    ... words, and in the model for the distribution of syllable length they are out of the range of values observed for word length (Popescu et al., 2013, pp. 229-233).21 The different strengths of correlations (for the relations between word frequencies and word length, and syllable frequencies and syllable ...

  • 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 ...
    Management, Monitoring, Policy and Law, Pollution, General Environmental Science, General Medicine

  • Age of the Jurassic hemipelagic sediments from the Ljubiš area (Zlatibor Mt., SW Serbia)

    Nikita Bragin, Nevenka Đerić (2020)
    Radiolaria, Dinarides, Jurassic, stratigraphy, Serbia
    ... deposits are common and wide­ spread in the territory of western and southwestern Serbia. Meso­ zoic radiolaria are found in pelagic and hemipelagic sediments deposited on the Neo-Tethys ocean floor, intercalated between Triassic shallow-water carbonate ramp and platform sediments, and are widespread ...
    ... mélange and Sirogojno Mélange), and belong to the parautoch­ thonous sequences between the Drina–Ivanjica Unit to the east and the East Bosnian Durmitor Unit to the west (GAWLICK et al., 2017). 3. SECTION DESCRIPTION AND BIOSTRATIGRAPHY The studied section is located in Donji Ljubiš Village and starts ...
    ... determination, stratigraphy, and facies are important for the reconstruction of tectonic motion and the arrangement of palaeo­oceanic basins and continental blocks. Due to the highly complicated structure of this territory, each palaeontological da­ tum from radiolarite deposits and from carbonate clasts ...

  • Part of Speech Tagging for Serbian language using Natural Language Toolkit

    Ranka Stanković, Boro Milovanović (2020)
    Dok se razvijaju složeni algoritmi za NLP (obrada prirodnog jezika), osnovni zadaci kao što je označavanje ostaju veoma važni i još uvek izazovni. NLTK (Natural Language Toolkit) je moćna Python biblioteka za razvoj programa zasnovanih na NLP-u. Pokušavamo da iskoristimo ovu biblioteku za kreiranje PoS (vrsta reči) oznake za savremeni srpski jezik. Jedanaest različitih modela je kreirano korišćenjem NLTK API-ja za označavanje. Najbolji modeli se transformišu sa Brill tagerom da bi se poboljšala tačnost. Obučili smo modele na označenom ...
    obrada prirodnog jezika, mašinsko učenje, neuronske mreže
    ... shows mapping between UD_POS and N_POS tags. In most cases it is one-to-one relation but there are some differences between tagsets. N_POS doesn’t differentiate between VERB and AUX, CCONJ and SCONJ, NOUN and PROPN. On the other hand, it separates SENT from PUNCT and PREF from X. The most frequent ...
    ... Krstev, and D. Vitas “Lexical Analysis of Serbian with Conditional Random Fields and Large-Coverage Finite-State Resources”, Proc. 7th Language and Technology Conference (LTC), Poznan, Poland, Nov. 2015 [8] N. Ljubešić, F. Klubička, Ž. Agić, and I. Jazbec, “New inflectional lexicons and training ...
    ... Šandrih, C. Krstev, M. Utvić, and M. Škorić, “Machine Learning and Deep Neural Network-Based Lemmatization and Morphosyntactic Tagging for Serbian,” Proc. International Conference on Language Resources and Evaluation, pp. 3954‑3962, May 2020 [24] A. Akbik, D. Blythe, and R. Vollgraf, “Contextual String ...

  • Some models for determination of parameters of the soil oscillation law during blasting operations

    Suzana Lutovac, Dragan Medenica, Branko Gluščević, Rade Tokalić, Čedomir Beljić (2018)
    ... explosive amount, and conditions of blasting and geologic characteristics of the soil; all of this being determined on the basis of test blasting for the specific work environment. In the Sadovskii equation two parameters, K and n appear and they are conditioned both by rock mass characteristics and blasting ...
    ... blast site to the monitoring point (m); r0—radius of the explosive charge; and n—exponent, conditioned by soil properties and mining conditions and determined by field measurements as well. The radius of the explosive charge r0 and the amount of explosive Q are related by the equation: Q “ 4 3 ¨ π ¨ r3 ...
    ... reduced distances for models 1, 2 and 3. The survey of reduced distances R, recorded oscillation velocities vr, calculated oscillation velocities vi1, vi2, and vi3, as well as the difference between the recorded and calculated soil oscillation velocities for models 1, 2, and 3, are presented in Table 2. ...

  • Structural characterization of traditional pottery produced from local clay, Rujište (Ražanj, Central Serbia), in an effort to preserve its geoheritage

    Maja Milošević, Biljana Đorđević, Alena Zdravković (2021)
    ... a mixture. As some of the slabs have rolled and rough edges they may be regarded as illite and/or halloysite. Morphology varies from short tubular, spheroidal and elongated tubules, which are the most common. EDS data confirmed hydroxides of illite and iron. Illite minerals deposited from formation ...
    ... Management and Events Ltd., Sofia Printing House: Bulged, Sofia 1505 Editors: Ruslan I. Kostov, Radostina Atanassova ISBN 978-954-92875-6-1 © Earth and Man National Museum, 2021 © Bulgarian Mineralogical Society, 2021 9th International Conference Mineralogy and Museums ...
    ... clay body based on mineralogy and applying the obtained knowledge in the preservation of this type of intangible cultural heritage, inscribed in the National register of ICH and as geoheritage in Serbia as well. The analysis of the phase, mineral composition and structure of the clay body was ...

  • Rift sequence stratigraphy and its contribution to source rock understanding – Serbian part of Pannonian Basin

    Filip Anđelković, Dejan Radivojević (2018)
    ... simple shear exten- sional mechanism (Matenco and Radivojević, 2012). The analysis of syn-kinematic reflectors demonstrates that normal faulting migrates in time and space and took place on a wide Miocene time interval (roughly 20–5.5 Ma) (Matenco and Radivojević, 2012). The most prolific source rocks ...
    ... (Eds). The Carpathians and their foreland: geology and hydrocarbon resources, AAPG Memoir 84, 619–632. Matenco, L. Radivojević, D. 2012. On the formation and evolution of the Pannonian Basin: Constraints derived from the structure of the junction area between the Carpathians and Dinarides. Tectonics ...
    ... rocks in Serbian part of Pannonian Basin are marls and limestones of the Sarmatian and Pannonian (Kostić, 2012). Besides this sequence, source rocks are also to a lesser extent rep- resented by shales of the Badenian and Pre-Badenian Tertiary, while the Lower Pontian shales were found to contain only ...

  • Crystal structure of K3EuSi2O7

    Sabina Kovač, Predrag Dabić, Aleksandar Kremenović (2021)
    alkalni silikati elemenata retkih zemalja, kristalna struktura, sinteza metodom fluksa, rendgenska difrakcija na monokristalu
    ... space group P63/mcm and is isostructural with disilicates K3ErSi2O7 15 and K3YbSi2O7. 22 The crystal structure is comparable to the sorosilicate structure type reported earlier by Vidican and co-authors.13 The crystal structure of the title compound consists of Si2O7 groups and EuO6 polyhedra which ...
    ... code: Eu atoms and polyhedra are grey, Si atoms are dark grey and O atoms are white. Fig. 3. Projection of structure along [120] showing two types of regularly alternating layers, which are parallel to the (001) plane: (I) octahedral layers and (II) sorosilicate layers. K atoms and polyhedra are ...
    ... black, Eu atoms and polyhedra are grey, SiO4 polyhedra are dark grey and O atoms are white. OnLin e Fir st 6 KOVAČ et al. The structure is characterized by two crystallographically distinct six- coordinated sites occupied by Eu1 and Eu2: Eu1O6 is an octahedron (OC-6) and Eu2O6 is a trigonal ...

  • NMR kinetic studies of the interactions between [Ru(terpy)(bipy)(H2O)]2+ and some sulfur-donor ligands

    Aleksandar Mijatović, Biljana Šmit, Ana Rilak, Biljana Petrović, Dragan Čanović, Živadin D. Bugarčić (2012)
    Reakcije supstitucije monofunkcionalnog [Ru(terpi)(bipi)(H2O)]2+ kompleksa, gde je terpi = 2,2′:6′,2″-terpiridin i bipi = 2,2′-bipiridin, sa biološki relevantnim sumporo donorskim ligandima, kao što su tiourea, l-metionin, l-cistein i glutation, proučavane su u vodenim rastvorima tehnikom 1H i 13C NMR spektroskopije. Sve reakcije su proučavajne na pH 7,4, u prisustvu fosfatnog pufera, da bi se oponašalo fiziološko okruženje tokom procesa supstitucije. Reakcije se izvode na 295 K pod uslovima reakcija drugog reda. Uočeni rezultati pokazuju da brzina supstitucije snažno zavisi ...
    Materials Chemistry,Inorganic Chemistry,Physical and Theoretical Chemistry

  • The influence of alkyl polyglucosides (and highly ethoxylated alcohol boosters) on the phase behavior of a water/toluene/technical alkyl polyethoxylate microemulsion system

    Marija Ilic, Franz-Hubert Haegel, Vesna Pavelkic, Dragan Zlatanovic, Snezana Nikolic-Mandic, Aleksandar Lolic, Zoran Nedic (2016)
    The influence of additives (alkyl polyglucoside, Glucopon 600 CS UP and alcohol ethoxylate C18E100) on the behavior of the water/toluene/Lutensol ON 50 (technical oxoalcohol, i-C10E5) microemulsion system as a function of temperature and composition has been investigated. The phase behavior of the microemulsions was determined by vertical sections through the Gibbs phase prism (fish-like phase diagrams). Alkyl polyglucoside shifts the one phase region to lower temperatures compared with water/toluene/Lutensol ON 50 mixtures. This is contrary to the expectation, considering ...
    микроемулзија, толуен, алкил полиглукозид, оксоалкохол етоксилат, појачивач ефикасности, „fish“ дијаграми
    ... RESULTS AND DISCUSSION The pseudo-binary phase diagrams of micro- emulsion systems were determined at equal mass fractions of water and toluene (a= 0.5) for two non- ionic surfactants, pure linear CxjEs and technical branched i-Cxo5Es (Lutensol ON 50) in order to find the composition and temperature ...
    ... exists consisting of a middle-phase microemulsion in equilibrium with excess phases of oil and water, surrounded by two-phase regions illustrated as 20 and 20 . When a surfactant is mainly dissolved in water and two phases consist of a surfactant-rich water (lower) phase in equilibrium with an excess ...
    ... surfactant needed to solubilize water and oil and is a measure for the efficiency of the surfactant. The corresponding temperature, f, is a measure for the phase inversion temperature (//7). The phase diagrams were recorded by success- ively adding water and oil to the initial water-oil-surf- ...

  • Non-Detonating Chemical Mixture for Non-Invasive Methods of Rock Breaking

    Lazar Kričak, Milanka Negovanović, Nikola Simić, Stefan Milanović (2024)
    Within the Innovation developed several different non-detonating chemical mixtures for non-invasive methods of rock breaking. Laboratory and polygon tests gave the satisfactory results and knowledge enough to start the practical experiments in the field. The basis of this innovation is a theoretical assumption that certain chemical mixtures release a large quantity of gases during combustion. If these gases are found in the enclosed space a growing pressure on the walls of the chamber in which combustion takes place will ...
    non-detonating, chemical mixture, rock breaking, borehole pressure

  • A Model for Determining Fuzzy Evaluations of Partial Indicators of Availability for High-Capacity Continuous Systems at Coal Open Pits Using a Neuro-Fuzzy Inference System

    Miljan Gomilanović, Miloš Tanasijević, Saša Stepanović, Filip Miletić (2023)
    This paper presents a model for determining fuzzy evaluations of partial indicators of the availability of continuous systems at coal open pits using a neuro-fuzzy inference system. The system itself is a combination of fuzzy logic and artificial neural networks. The system availability is divided into partial indicators. By combining the fuzzy logic and artificial neural networks, a model is obtained that has the ability to learn and uses expert judgment for that learning. This paper deals with the ...
    системи, континуални системи експлоатације (роторни багер-транспортер-дробилично постројење), рударство, расположивост, меко рачунарство, фази логика, ANN, ANFIS

  • Geologic Information System of Serbia

    Branislav Blagojević, Branislav Trivić, Ranka Stanković, Nenad Banjac, Olivera Kitanović (2011)
    Geologic information system of Serbia (GeolISS) represents repository for digital archiving, query, retrieving, analysis and geologic data visualization. The GeolISS is implemented through ESRI ArcGIS technology, and is designed to operate as a personal geodatabase (MS Jet 4.0 Engine) and SDE enterprise geodatabase in MS SQL Server. The objective of GeolISS implementation is integration of existing geologic archives, data from published maps at different scales, newly acquired field data, as well as Web publishing of geologic information. Physical implementation ...
    Geologic information system, Conceptual model, Logical model, Implementation, Geodatabase
    ... Mining and Geology, Đušina 7, 11000 Belgrade, Serbia, e-mail: btrivic@rgf.bg.ac.rs 3 Faculty of Mining and Geology, Đušina 7, 11000 Belgrade, Serbia, e-mail: ranka@rgf.bg.ac.rs 4 Faculty of Mining and Geology, Đušina 7, 11000 Belgrade, Serbia, e-mail: olja@rgf.bg.ac.rs 5 Faculty of Mining and Geology ...
    ... implement field data records and measurements i.e. the basis for classified features, interpretations and models. Any observed property can be expressed as a text, number, picture and geometry (location). Spatial entities are treated as observation localities and mapped/interpreted geologic entities ...
    ... references and persons involved and responsible for data acquisition. Metadata also include essential information’s about project, for which the data are to be collected. For data entry in GeolISS database designed special ArcGIS extension was designed and implemented in MS Visual Studio and ArcObject ...

  • Mine ventilation system planning using genetic algorithms

    Nikola Lilić, Ranka Stanković, Ivan Obradović (1997)
    The most common problem in contemporary mining practice related to the planning and analysis of ventilation systems is the optimization of partially regulated air distribution in mine ventilation networks. This paper presents a two step optimization procedure for partly regulated air distribution in mine ventilation networks. The first step is the determination of air distribution in all branches using the well known Hardy-Cross method. In the second step the distribution and parameters of air flow regulators with minimum engaged ...
    coal, lignite, and peat; ventilation systems; coal mining; underground mining; ventilation; mathematical models; design; air flow; optimization; calculation methods

  • 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
    ... [CrossRef] 12. Harris, T.J.; Yuan, H. Filtering and frequency interpretations of Singular Spectrum Analysis. Phys. D 2010, 239, 1958–1967. [CrossRef] 13. Hassani, H.; Zhigljavsky, A. Singular Spectrum Analysis: Methodology and Application to Economics Data. J. Syst. Sci. Complex. 2009, 22, 372–394. ...
    ... MAPEi, (30) MAPEi and AMAPE are represented in Table 10. Energies 2021, 14, 3710 15 of 20 Within the grouping step, we only have signal and noise components and we use two groups of indices, I; = {Avy,,Ay, } and Iz = {Av,,Ay, } and associate the group I; with signal component and the group I with noise ...
    ... function of time and the face advance. A procedure based on analytical functions has been developed to support the prediction of the tunnel performance and surface movements. Merlini and Falanesca [10] illustrated the comparison between the prognosis and the crosscheck of the support methods and the replacement ...

  • 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

  • Natural two-dimensional pyrophyllite: Nanoscale lubricant, electrical insulator and easily-machinable material

    Borislav Vasić, Radoš Gajić, Ivana Milošević, Žarko Medić, Marina Blagojev, Marko Opačić, Aleksandar Kremenović, Dejan Lazić (2022)
    Pyrophyllite, with the chemical formula Al2Si4O10(OH)2, is a naturally occurring and abundant van der Waals mineral belonging to the group of phyllosilicates. It is very soft, layered crystal used for sculpting and an excellent electrical and thermal insulator aimed for the operation at high pressure and temperature. Here, for the first time, two-dimensional (2D) pyrophyllite obtained by both mechanical and liquid phase exfoliation is presented and investigated at the nanoscale. The layered structure provides low friction coefficient of around ...
    Atomic force microscopy, Insulating properties, Nanofriction and wear, Natural two dimensional materials, Phyllosilicates, Pyrophyllite