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149 items

The number of nonunimodular roots of a reciprocal polynomial
Dragan Stankov (2023)We introduce a sequence Pd of monic reciprocal polynomials with integer coefficients having the central coefficients fixed as well as the peripheral coefficients. We prove that the ratio of the number of nonunimodular roots of Pd to its degree d has a limit L when d tends to infinity. We show that if the coefficients of a polynomial can be arbitrarily large in modulus then L can be arbitrarily close to 0. It seems reasonable to believe that if ...Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, SchinzelZassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "The number of nonunimodular roots of a reciprocal polynomial" in Comptes rendus mathematique, Elsevier France Editions Scientifiques et Medicales (2023). https://doi.org/10.5802/crmath.422

The number of unimodular roots of some reciprocal polynomials
Dragan Stankov (2020)We introduce a sequence P2n of monic reciprocal polynomials with integer coefficients having the central coefficients fixed. We prove that the ratio between number of nonunimodular roots of P2n and its degree d has a limit when d tends to infinity. We present an algorithm for calculation the limit and a numerical method for its approximation. If P2n is the sum of a fixed number of monomials we determine the central coefficients such that the ratio has the minimal limit. ...Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, SchinzelZassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "The number of unimodular roots of some reciprocal polynomials" in Cmptes rendus mathematique (2020). https://doi.org/10.5802/crmath.28

The Reciprocal Algebraic Integers Having Small House
Dragan Stankov (2021)Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, SchinzelZassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "The Reciprocal Algebraic Integers Having Small House" in Experimental Mathematics (2021). https://doi.org/ 10.1080/10586458.2021.1982425

A necessary and sufficient condition for an algebraic integer to be a Salem number
Dragan Stankov (2019)We present a necessary and sufficient condition for a root greater than unity of a monic reciprocal polynomial of an even degree at least four, with integer coefficients, to be a Salem number. This condition requires that the minimal polynomial of some power of the algebraic integer has a linear coefficient that is relatively large. We also determine the probability that an arbitrary power of a Salem number, of certain small degrees, satisfies this condition.Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, SchinzelZassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "A necessary and sufficient condition for an algebraic integer to be a Salem number" in Journal de theorie des nombres de Bordeaux (2019). https://doi.org/10.5802/jtnb.1076

On the distribution modulo 1 of the sum of powers of a Salem number
Dragan Stankov (2016)It is well known that the sequence of powers of a Salem number θ, modulo 1, is dense in the unit interval, but is not uniformly distributed. Generalizing a result of Dupain, we determine, explicitly, the repartition function of the sequence , where P is a polynomial with integer coefficients and θ is quartic. Also, we consider some examples to illustrate the method of determination.Algebraic integer, the house of algebraic integer, maximal modulus, reciprocal polynomial, primitive polynomial, SchinzelZassenhaus conjecture, Mahler measure, method of least squares, cyclotomic polynomialsDragan Stankov. "On the distribution modulo 1 of the sum of powers of a Salem number" in Comptes rendus Mathematique (2016). https://doi.org/10.1016/j.crma.2016.03.012

Indexing of textual databases based on lexical resources: A case study for Serbian
In this paper we describe an approach to improvement of information retrieval results for large textual databases by preindexing documents using bagofwords and Named Entity Recognition. The approach was applied on a database of geological projects financed by the Republic of Serbia in the last half century. Each document within this database is described by metadata, consisting of several fields such as title, domain, keywords, abstract, geographical location and the like. A bag of words was produced from these ...... based on tf idf measure. Evaluation of ranked retrieval results based on data obtained by preindexing are com pared to results obtained by informational retrieval without preindexing with PrecisionRecall Curve, showing a significant improvement in terms of Mean Average Precision measure (MAP). 1 In ...
... logarithm, and finally the lnu ltu which uses the document length and the average length of documents instead of cosine measure for normalizing length. [3] The improved ranking uses tf idf measure that is based on frequencies of words allocated to the text, text length, and the document frequency [8]. Index ...
... organized in cascades that further resolve ambiguities [10]. NER system was evaluated on a newspaper corpus and results reported in [7] showed that F measure of recognition was 0.96 for types and 0.92 fot tokens. For the purpose of indexing, we applied our NER system to title and abstract fields of our ...Ranka Stanković, Cvetana Krstev, Ivan Obradović, Olivera Kitanović. "Indexing of textual databases based on lexical resources: A case study for Serbian" in Semantic Keywordbased Search on Structured Data Sources : First COST Action IC1302 International KEYSTONE Conference, IKC 2015, Coimbra, Portugal, September 89, 2015. Revised Selected Papers, Springer (2015). https://doi.org/10.1007/9783319279329_15

Prioritization of strategic measures for strengthening the security of supply of the Serbian natural gas sector
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 indikatoriBoban Pavlović, Dejan Ivezić, Marija Živković. "Prioritization of strategic measures for strengthening the security of supply of the Serbian natural gas sector" in Energy Policy, Elsevier BV (2020). https://doi.org/10.1016/j.enpol.2020.111936

On the compatibility of lexical resources for NooJ
Lexical resources for many languages are provided for the NooJ linguistic development environment. Metadata descriptions of morphosyntactic and semantic properties of these languages and their resources are a mandatory part of each language module. In this paper we analyze how well the metadata actually describe resources for a chosen subset of languages and to what extent are they compatible across languages to support multilingual processing. We show that there is place for improvement in both directions.... after they recognize one or more numbers connected by a comma or a conjunction (or ), invoke their specific „measure“ sub graphs which recognize different measure units, either as character strings: kilometer, meter, foot, feet, pond, mile, or as patterns , . An example ...
... osamdeset miliona ljudi. However, a more detailed analysis of aligned text revealed examples where a measure expression was recognized in some but not in all languages. For instance, a measure expression “four hundred horse power” was recognized in English and Croatian, but not in Serbian, because ...
... version simplified for this occasion. Figure 1 depicts the main graphs for English, Serbian and Croatian texts. Fig 1. Graph examples for measure expressions (Entop, Srmiddle, Hrbottom) 10 [Type text] The differences in the graphs result from different ways categories and properties ...Ranka Stanković, Miloš Utvić, Duško Vitas, Cvetana Krstev, Ivan Obradović. "On the compatibility of lexical resources for NooJ" in Automatic Processing of Various Levels of Linguistic Phenomena: Selected Papers from the 2011 International Nooj Conference, Cambridge Scholars Publishing (2012): 96108

TransformerBased Composite Language Models for Text Evaluation and Classification
Parallel natural language processing systems were previously successfully tested on the tasks of partofspeech tagging and authorship attribution through minilanguage modeling, for which they achieved significantly better results than independent methods in the cases of seven European languages. The aim of this paper is to present the advantages of using composite language models in the processing and evaluation of texts written in arbitrary highly inflective and morphologyrich natural language, particularly Serbian. A perplexitybased dataset, the main asset for the ...Mihailo Škorić, Miloš Utvić, Ranka Stanković. "TransformerBased Composite Language Models for Text Evaluation and Classification" in Mathematics, MDPI AG (2023). https://doi.org/10.3390/math11224660

Mapping and classifying large deformation from digital imagery: application to analogue models of lithosphere deformation
kontinentalna tektonika: kompresija, kontinentalna tektonika: ekstenzija, kontinentalna tektonika: transkurentni i transformni rasedi, pukotine, rasedi, zone snažnih deformacija, kinematika deformacija kore i omotača, teorijska mehanika, modelovanje... shear all material lines rotate except for the lines parallel with the direction of shear, this has no effect on the strain type measure. Namely, our strain type measure only considers principal strain magnitudes, and does not take into account principal direction changes. Even though pure shear in ...
... ional and transtensional transitions, can be adequately described using our developed qualitative strain type measure. Due to the temporal and spatial continuous description, this measure can be used to inspect the temporal evolution of strain, even in the absence of discrete structures. AVA I L A ...
... field as a function of time. To describe cumulative, finite deformation, various strain tensors have been developed, and we discuss what strain measure best describes large shape changes, as standard infinitesimal strain tensors no longer apply for large deformation. PIV or comparable techniques ...Taco Broerse, Nemanja Krstekanić, Cor Kasbergen, Ernst Willingshofer. "Mapping and classifying large deformation from digital imagery: application to analogue models of lithosphere deformation" in Geophysical Journal International, Oxford University Press (OUP) (2021). https://doi.org/10.1093/gji/ggab120

The Impact Assessment of NO2 Emission from District Heating Plant on Local Air Quality, the Case of Zemun, Belgrade
The Belgrade district heating system relies on fossil fuels in heat production, where natural gas has the largest share of around 95% and fuel oil with around 4.4%. The Zemun heating plant is completely fueled with fuel oil. Currently, it is the largest plant that is not fueled with natural gas. The objective of this paper is to assess the impact of NO2 from the Zemun heating plant on local air quality by analyzing and comparing the concentration of ...NO2, Zagađenje vazduha, Kvalitet vazduh na lokalnom nivou, Model disperzije, AERMOD, Daljinsko grejanje, BeogradBoban Pavlović, Uroš Pantelić, Marija Živković, Dejan Ivezić. "The Impact Assessment of NO2 Emission from District Heating Plant on Local Air Quality, the Case of Zemun, Belgrade" in Conference on Sustainable Development of Energy, Water and Environment Systems, Dubrovnik, 10.10.15.10.2021., University of Zagreb, Zagreb, Croatia; Instituto Superior Técnico, Lisbon, Portugal (2021)

Ground surface subsidence monitoring using sentinel1 in the “Kostolac” open pit coal mine
Zoran Gojković, Milan Kilibarda, Ljiljana Brajović, Miloš Marjanović, Aleksandar Milutinović, Aleksandar Ganić (2023)Open pit coal mining affects surrounding populated areas, resulting in terrain surface deformation. Surface deformation should be monitored as often as possible to control deformations and prevent potential incidents. This paper analyzes time series deformation estimated from the Sentinel1 satellite images using the Persistent Scatterer Interferometry method to monitor subsidence rates caused by open pit mining activities. It is possible to measure deformations using classical geodetic methods, but those are rarely used in practice because they are timeconsuming and ...Zoran Gojković, Milan Kilibarda, Ljiljana Brajović, Miloš Marjanović, Aleksandar Milutinović, Aleksandar Ganić. "Ground surface subsidence monitoring using sentinel1 in the “Kostolac” open pit coal mine" in Remote Sensing (2023). https://doi.org/10.3390/rs15102519

Concepts for Improving Machine Learning Based Landslide Assessment
Miloš Marjanović, Mileva Samardžić Petrović, Biljana Abolmasov, Uroš Đurić. "Concepts for Improving Machine Learning Based Landslide Assessment" in Natural Hazards GISbased Spatial Modeling Using Data Mining Techniques, Advances in Natural and Technological Hazards Research, volume 48, Springer Nature Switzerland AG 2019 (2019). https://doi.org/10.1007/9783319733838_2

A comparison between ARIMA, LSTM, ARIMALSTM and SSA for crossborder rail freight traffic forecasting: the case of AlpineWestern Balkan Rail Freight Corridor
Miloš Milenković, Miloš Gligorić, Nebojša Bojović, Zoran Gligorić. "A comparison between ARIMA, LSTM, ARIMALSTM and SSA for crossborder rail freight traffic forecasting: the case of AlpineWestern Balkan Rail Freight Corridor" in Transportation Planning and Technology, Informa UK Limited (2023). https://doi.org/10.1080/03081060.2023.2245389

Improving Document Retrieval in Large Domain Specific Textual Databases Using Lexical Resources
Large collections of textual documents represent an example of big data that requires the solution of three basic problems: the representation of documents, the representation of information needs and the matching of the two representations. This paper outlines the introduction of document indexing as a possible solution to document representation. Documents within a large textual database developed for geological projects in the Republic of Serbia for many years were indexed using methods developed within digital humanities: bagofwords and named ...... lnu ltu which uses the document length and the average length of documents instead of cosine measure for normalizing length [8]. The improved system ranking uses several measures, starting with tf idf measure based on frequencies of words allocated to the text, text length, and the document frequency ...
... organized in cascades that further resolve ambiguities [16]. NER system was evaluated on a newspaper corpus and results reported in [13] showed that F measure of recognition was 0.96 for types and 0.92 for tokens.3 3 Tokens are all occurrences (in this case, NEs) in a given texts, types are different occurrences ...
... o f Improving Document Retrieval in Large Domain Specific Textual Databases 11 with normalized tf factor for the query term weights, lnc ltc measure where l stands for weights with a logarithmic tf component, lnu ltu where normaliza tion is based on the number of unique words in text, as well as ...Ranka Stanković, Cvetana Krstev, Ivan Obradović, Olivera Kitanović. "Improving Document Retrieval in Large Domain Specific Textual Databases Using Lexical Resources" in Trans. Computational Collective Intelligence  Lecture Notes in Computer Science 26, Springer (2017). https://doi.org/10.1007/9783319592688_8

Evaluation And Perspectives Of Underground Coal Mines In Serbia
... in the AHP method, a certain level of inconsistency may occur. Therefore, the logical consistency of pairwise comparisons must be checked [6]. To measure the consistency of pairwise comparison judgments, the consistency ratio proposed by Saaty [7] is used. A consistency ratio is calculated for the ...
... order to accept the results of the weighting. The parameter that is used to check this is called the Consistency Ratio. The consistency ratio is a measure of how much variation is allowed and must be less than 10%. Finally, random index (RI) is given in Table 6. Table 4. Pairwise comparison matrix ...Vladimir Milisavljević, Milena Lekić, Ivica Ristović, Vojin Čokorilo, Aleksandar Cvjetić. "Evaluation And Perspectives Of Underground Coal Mines In Serbia" in 7th Balkan Mining Congress Preceedings  BalkanMine2017, Prijedor, 1113. oktobar 2017., Banjaluka : University of Banjalika, Faculty of Mining, RS, BiH (2017)

Development of the Availability Concept by Using Fuzzy Theory with AHP Correction, a Case Study: Bulldozers in the OpenPit 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 ...... The term availability is used to denote the degree of functional safety. Availability is expressed in quantitative indicators, and as such, is a measure of functional safety, and thus of the quality of service. Monitoring and availability analysis are significant because of the known fact that the ...
... The term availability is used to denote the degree of functional safety. Availability is expressed in quantitative indicators, and as such, is a measure of functional safety, and thus of the quality of service. Monitoring and availability analysis are significant because of the known fact that the machine ...
... (MILSTD) Energies 2019, 12, 4044; doi:10.3390/en12214044 www.mdpi.com/journal/energies Energies 2019, 12, 4044 2 of 18 defines availability as a measure of the degree to which an item is in an operable state and can be committed at the start of a mission when the mission is called for at an unknown ...Stevan Đenadić, Dragan Ignjatović, Miloš Tanasijević, Uglješa Bugarić, Ivan Janković, Tomislav Šubaranović. "Development of the Availability Concept by Using Fuzzy Theory with AHP Correction, a Case Study: Bulldozers in the OpenPit Lignite Mine" in Energies, MDPI AG (2019). https://doi.org/10.3390/en12214044

Characterization of Natural Clay from Bogovina (Serbia) and Possible Utilization in Sorption of the Herbicides
... was Ca montmorillonite. The whole modification process was monitored using several methods. The batch adsorption method was used to measure the efficiency of inorganic and organic modified montmorillonites for the sorption of the Smetolachlor. Mineralogical characterization ...Lazar Kaluđerović, Zorica Tomić, Rada ĐurovićPejčev, Maja Milošević. "Characterization of Natural Clay from Bogovina (Serbia) and Possible Utilization in Sorption of the Herbicides" in Eurosoil2020, online event 2021, Eurosoil, Frontiers Abstract Book (2021)

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... induction to measure flow. When a fluid passes through an electromagnetic field, an electromotive force is generated that is proportional to the flow rate. These sensors are suitable for measuring conductive fluids. Figure5.6 Electromagnetic sensors 4.Capacitive sensors – These measure changes in ...
... sensors  Measure temperature without contact by detecting infrared rays emitted by an object. They detect infrared radiation and convert it into an electrical signal that represents the object's temperature. Infrared sensors are useful in situations where it is difficult or impossible to measure temperature ...
... sensors allow for timely detection of abnormal pressures that may indicate malfunctions or inefficiencies in the pumps. Their ability to accurately measure pressure ensures proper monitoring and maintenance of the system, preventing potential issues and enhancing the reliability and performance of ...Maja Trikić. Application of machine learning for diagnosing the operation of a deep well pump in oil production, 2024

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, FranzHubert Haegel, Vesna Pavelkic, Dragan Zlatanovic, Snezana NikolicMandic, 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, iC10E5) 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 (fishlike 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... region, defines the mini mum mass fraction of 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 ...
... nonionic surfactanUwater/oil microemulsions are very interesting scientifically and technically. A convenient way to study these systems is to measure the phase behavior at constant oil/water ratios as a function of temperature, 7, and surfactant . mass fraction, ». Correspondence: M. Ilić ...Marija Ilic, FranzHubert Haegel, Vesna Pavelkic, Dragan Zlatanovic, Snezana NikolicMandic, Aleksandar Lolic, Zoran Nedic. "The influence of alkyl polyglucosides (and highly ethoxylated alcohol boosters) on the phase behavior of a water/toluene/technical alkyl polyethoxylate microemulsion system" in Chemical Industry and Chemical Engineering Quarterly, National Library of Serbia (2016). https://doi.org/ 10.2298/CICEQ141105015I