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Упит dcterms_subject_txt:prediktivno održavanje PdM 4.0

918 items

  • Improving Document Retrieval in Large Domain Specific Textual Databases Using Lexical Resources

    Ranka Stanković, Cvetana Krstev, Ivan Obradović, Olivera Kitanović (2017)
    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: bag-of-words and named ...

  • The Dictionary of the Serbian Academy: from the Text to the Lexical Database

    Ranka Stanković, Rada Stijović, Duško Vitas, Cvetana Krstev, Olga Sabo (2018)
    In this paper we discuss the project of digitization of the Dictionary of the Serbo-Croatian Standard and Vernacular Language. Scanning and character recognition were a particular challenge, since various non-standard character set encoding was used in the course of the almost 60-year long production of the dictionary. The first aim of the project was to formalize the micro-structure of the dictionary articles in order to parse the digitized text of and transform it into structured data stored in relational lexical database. This approach ...
    computer lexicography, lexical database, language resources, dictionary, Serbian language

  • The use of biological markers in determination of origin and type of organic matter in the Tisza river sediments

    Snežana Štrbac, Gordana Gajica, Aleksandra Šajnović, Nebojša Vasić, Ksenija Stojanović, Branimir Jovančićević (2013)
    The objective of the study was to determine the origin and type of organic matter (OM) of the Tisza recent sediments along the distance of 153 km through the territory of Serbia. For this purpose group organic-geochemical parameters and biomarker compositions were used. All samples contain approximately same amount of OM, which was deposited under uniform, slightly reducing conditions. Based on the distribution of n-alkanes, the origin and type of OM could not be precisely estimated. However, n-alkane patterns ...
    sediments, Tisza River, organic matter, biomarkers, oil pollutants

  • The Usage of Various Lexical Resources and Tools to Improve the Performance of Web Search Engines

    Krstev Cvetana, Stanković Ranka, Vitas Duško, Obradović Ivan (2008)
    In this paper we present how resources and tools developed within the Human Language Technology Group at the University of Belgrade can be used for tuning queries before submitting them to a web search engine. We argue that the selection of words chosen for a query, which are of paramount importance for the quality of results obtained by the query, can be substantially improved by using various lexical resources, such as morphological dictionaries and wordnets. These dictionaries enable semantic ...
    LR web services, MultiWord Expressions & Collocations, Information Extraction, Information Retrieval

  • Improving efficiency of thermal power plants through mine coal quality planning and control

    Mirjana Banković, Dejan Stevanović, Milica Pešić, Aleksandra Tomašević, Ljiljana Kolonja (2018)
    Главни циљ контроле квалитета угља у рудницима лигнита је снабдевање термоелектрана угљем чији квалитет мора да се креће унутар одређених квалитативних ограничења. Карактеристике угља могу да утичу на ефикасност, поузданост и расположивост како котла тако и јединица за контролу емисије. У овом раду аутори су презентовали интегрисану симулацију рударског процеса као нови приступ у истраживању променљивости калоричне вредности угља приликом експлоатације комплексног лежишта лигнита. Резултати таквог приступа омогућавају драгоцен увид у перформансе континуалног рударског система у смислу контроле променљивости ...
    mine planning, variability of coal quality, simulation, coal blending

  • Environmental Energy Security Indicators as Tools for Environmental Protection

    Aleksandar Madžarević, Dejan Ivezić, Marija Živković , Miloš Tansijević (2019)
    Еколошка прихватљивост је постала незаменљив синтезни показатељ сваке валидне енергетске анализе у последње две-три деценије. Енергетска безбедност је у директној хармонији с еколошком прихватљивошћу кроз многе прописане политичке циљеве, економске користи, правне тековине итд. Индикатори еколошке сигурности представљају један од основних елемената за одређивање енергетске безбедности и снажне алате за усмеравање енергетског сектора ка одрживом развоју. У овом раду, анализа је била концентрисана на показатеље енергетске безбедности у области животне средине који се односе на сектор природног гаса у ...
    енергетска безбедност, еколошки енергетски индикатори, заштита животне средине, еколошка прихватљивост

  • The State and Perspective of Belgrade District Heating System Development

    Dejan Ivezić, Marija Živković, Aleksandar Madžarević, Fethi Silajdžić, Samra Arnaut, Goran Đelić (2019)
    District heating (DH) system in Belgrade provides energy for heating of more than 21 million m2 in households (app. 50% of all households), public, commercial and industry sectors. Public Utility Company “Beogradske elektrane” is responsible for all segments of the DH system operation. The system is fueled mostly by natural gas. The share of renewables is negligible. The research analyzes effects of implementation of two main projects proposed in the Development Strategy of the PUC - the introduction of ...
    daljinsko grejanje, Beograd, razvoj

  • Anisotropic grossular–andradite garnets: Evidence of two stage skarn evolution from Rudnik, Central Serbia

    Bojan Kostić, Danica Srećković-Batoćanin, Petyo Filipov, Pavle Tančić, Kristijan Sokol (2021)
    This paper presents LA-ICP-MS data for garnets from the Rudnik skarn deposit (Serbia), which range from Grs45–58Adr40–52Alm2–3 in the core and Adr70–97Grs2–29Sps1 in the rim displaying anisotropy and zoning. In spite of wide compositional variations the garnets near the end-member of andradite (Adr > 90) are generally isotropic. Fe-rich rims exhibit LREE depletion and flat HREE pattern with weak negative Eu anomaly, including higher As and W contents. On the other side, the Fe-poorer core shows flat REE pattern ...
    grandite, garnets, skarn, Rudnik

  • Life Cycle Assessment of Individual Wood Biomass Heating Systems in Households

    Boban Pavlović, Dejan Ivezić, Marija Živković (2020)
    The use of solid fuels (wood biomass and coal) for heating of households continues to be common practice within European countries. Solid fuel combustion in households contributes more than 46% to total emissions of fine particulate matter. In this study, a life-cycle assessment (LCA) of firewood-based and pellet-based heating systems is performed. These two systems represent two different types of individual wood biomass heating systems. In the case of the firewood-based heating systems, it is analyzed a typical stove ...
    Grejanje, Analiza životnog ciklusa, Drvna biomasa, Individualni sistemi grejanja

  • Serbian NER&Beyond: The Archaic and the Modern Intertwinned

    Branislava Šandrih Todorović, Cvetana Krstev, Ranka Stanković, Milica Ikonić Nešić (2021)
    U ovom radu predstavljamo srpski književni korpus koji se razvija pod okriljem COST Akcije „Distant Reading for European Literary History” CA16204. Koristeći ovaj korpus romana napisanih pre više od jednog veka, razvili smo i učinili javno dostupnim Sistem za prepoznavanje imenovanih entiteta (NER) obučen da prepozna 7 različitih tipova imenovanih entiteta, sa konvolucionom neuronskom mrežom (CNN), koja ima F1 rezultat od ≈91% na test skupu podataka. Ovaj model je dalje ocenjen na posebnom skupu podataka za evaluaciju. Završavamo poređenje ...

  • 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

  • Permanent GNSS monitoring of landslide Umka

    Mileva Samardžić Petrović, Jovan Popović, Uroš Đurić, Biljana Abolmasov, Marko Pejić, Miloš Marjanović (2020)
    Клизиште Умка је једно од највећих насељених активних клизишта у Србији. Активност клизишта Умка се прати већ више од 85 година, различитим геотехничким и геодетским техникама. Од 2010. године, активност kлизишта се континуирано прати у реалном времену аутоматизованим перманентним системом за праћење базираним на Глобалним навигационим сателитским системима (ГНСС). Поред тога, од 2018. године активност клизишта се додатно прати кинематичким ГНСС одређивањем положаја скупа карактеристичних тачака као и применом UAV фотограметрије. Главни циљ овог рада је приказ резултата опажања три ...
    клизиште, перманентно праћење, ГНСС

  • Terminological and lexical resources used to provide open multilingual educational resources

    Biljana Lazić, Danica Seničić, Aleksandra Tomašević, Bojan Zlatić (2016)
    Open educational resources (OER) within BAEKTEL (Blending Academic and Entrepreneurial Knowledge in Technology enhanced learning) network will be available in different languages, mostly in the languages of Western Balkans, Russian and English. University of Belgrade (UB) hosts a central repository based on: BAEKTEL Metadata Portal (BMP), terminological web application for management, browse and search of terminological resources, web services for linguistic support (query expansion, information retrieval, OER indexing, etc.), annotation of selected resources and OER repository on local edX ...
    otvoreni obrazovni resursi, leksički resursi, obrada prirodnih jezika, terminologija

  • Mogućnost korišćenјa toplotnih pumpi sa otpadnom toplotom iz postrojenјa za prečišćavanјe otpadnih voda kao toplotnim izvorom

    Dejan Ivezić, Marija Živković, Aleksandar Madžarević, Boban Pavlović (2021)
    U narednom periodu se planira izgradnja nekoliko desetina sistema za prečišćavanje otpadnih voda u većim gradovima u Srbiji. Iskustva iz postrojenja koja su trenutno u radu, pokazuju da bi prečišćena otpadna voda, s obzirom na protok i temperaturu, mogla da predstavlja značajan izvor obnovljive energije. U radu su prikazani primeri dobre prakse korišćenja ove energije u sistemima daljinskog grejanja u zemljama Evropske unije. Analiziran je rad postrojenja za prečišćavanje otpadnih voda u Šapcu i razmotrena je mogućnost njegovog korišćenja ...
    toplotna pumpa, sistem daljinskog grejanja, postrojenje za prečišćavanje otpadnih voda

  • The optimization of auxiliary machinery in open-cast lignite mines: a case study of bulldozers

    Dragan Ignjatović, Predrag Jovančić, Stevan Đenadić, Ivan Janković, Ivica Ristović (2019)
    One of the most important prerequisites for the successful operation of the open-cast lignite mine is to carry out all the auxiliary works timely with the necessary quality. The most important and most commonly used auxiliary machines are bulldozers. Engaging time of bulldozers use is in direct relation with the coefficients of the time and capacity utilization of the continuous system for the excavation of coal and tailings, which indicates their importance. More than 100 bulldozers have been hired ...
    open-cast coal mine, auxiliary works, bulldozers, optimization, availability

  • Valorization of non-balanced coal reserves in Serbia for underground coal gasification

    David Petrović, Lazar Kričak, Milanka Negovanović, Stefan Milanović, Jovan Marković, Nikola Simić, Ljubisav Stamenić (2019)
    In the name of a better and safer energy future, it is our responsibility to focus our knowledge and activities to save on imported liquid and gas fossil fuels, as well as coal on which energy security of Serbia is based. The rationalization in the use of available energy resources certainly positively affects economy and the environment of a country. This paper indicates motivations for the application of the underground coal gasification process, as well as surface gasification for ...
    ugalj, gasifikacija, zaštita životne sredine, skladištenje, solarni

  • Witness of the history: A hundred years old the geological hammer of Jovan Zujovic

    Ljupko Rundić (2021)
    Током обележавања тридесет година постојања и рада Српског геолошког друштва 10. фебруара 1921. године, у знак великог поштовања према академику Јовану Жујовићу, председнику и оснивачу Српског геолошког друштва и српске геолошке школе, чланови СГД поклонили су му јединствени геолошки чекић са угравираном посветом и својим потписима. Током протеклих стотину година, многе генерације геолога проналазиле су инспирацију гледајући чекић и делећи ову причу с великим пијететом. Данас, када геолози посећују Спомен собу геологије (Рударско-геолошки факултет, ул. Каменичка бр. 6), где се пажљиво ...
    Геолошки чекић, Јован Жујовић, Српско геолошко друштво, 1921–2021

  • Geostatički proračuni

    Gordana Hadži-Niković (2020)
    geostatika

  • Petrologija magmatskih i metamorfnih stena - praktikum

    Kristina Šarić (2014)
    petrologija, magmatske stene, metamorfne stene

  • Novel Methods in Multiple Criteria Decision-Making Process (MCRAT and RAPS)—Application in the Mining Industry

    Katarina Urošević, Zoran Gligorić, Igor MIljanović, Čedomir Beljić, Miloš Gligorić (2021)
    Multiple criteria decision making (MCDM) is a supporting tool which is widely spread in different areas of science and industry. Many researchers have confirmed that MCDM methods can be useful for selecting the best solution in many different problems. In this paper, two novel methods are presented and applied on existing decision-making processes in the mining industry. The first method is multiple criteria ranking by alternative trace (MCRAT) and the second is ranking alternatives by perimeter similarity (RAPS). These ...
    višekriterijumsko odlučivanje, nove metode, rudarstvo, šeme miniranja