Претрага
157 items
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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, Schinzel-Zassenhaus 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
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Application of Project Management Process on Environmental Management System Improvement in Mining-Energy Complexes
... probability (P) and the measure of loss (L) it inflicts: R = f(P, L) (1) Energies 2016, 9, 1071 6 of 20 Actualization of a risk event in a mining and energy complex leads to heavier or smaller economic loss, but also to serious consequences for the environment or loss as non-economic measure [22]. ...
... + 1 36 30 Unfavorable ash and water ratio in the thick pulp 5 3 1 + 0 + 1 + 0 + 0 + 1 60 31 Increased concentration of heavy metals in overflowing, drainage, and leachate water 5 3 1 + 0 + 1 + 1 + 0 + 1 60 32 Increased acidity of overflowing, drainage, and leachate water 5 3 1 + 0 + 1 + 1 + 0 + 1 60 33 ...
... environment, as all the basic elements of the environment (air, water, and soil) are threatened, not just one. Mining and energy complexes significantly reduce the quality of the immediate environment, as the distance areas throughout water and air pollution propagation. Additional motivation for this ...Jelena Malenović Nikolić, Dejan Vasović , Ivana Filipović , Stevan Mušicki, Ivica Ristović . "Application of Project Management Process on Environmental Management System Improvement in Mining-Energy Complexes" in Energies (2016). https://doi.org/https://doi.org/10.3390/en9121071
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Development Of The Serbian Geological Resources Portal
... Djerdap, DRAGIŠIĆ, Monitoring groundwater resources of Serbia: Drafting the map of the vulnerability of underground water resources of Serbia, 2007-2011. (together with the Institute for water management “Jaroslav Cerni”), STEVANOVIĆ, Z. 2009., Translation of the published cartographic content and the content ...
... at http://geoliss.rgf.rs/index.php?page=atlas, was created with the use of Adobe flash plug-in Zoomify, which enables zooming in real-time, without loss of image quality. Multimedia part of the web portal The part of the web portal pertaining to geoheritage and geodiversity of North-Western Serbia ...
... for searching cata- logues: projects, archive documentation and bibliog- raphy, documentation of the funds and research- exploitation permits for water and solid mineral resources10. The above-mentioned searches were derived from the basic model which is based on mul- tiple entry of key words, phrases ...Ranka Stanković, Jelena Prodanović, Olivera Kitanović, Velizar Nikolić. "Development Of The Serbian Geological Resources Portal" in Proceedings of the 17th Meeting of the Association of European Geological Societies, Belgrade, Serbia : The Serbian Geological Society (2011)
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Self-Engineering: Possibilities for Maintenance Operations in the Mining Machines Industry
Self-engineering is a relatively new branch of knowledge that aims to understand how systems could “autonomously” re-configure or repair themselves without the intervention of the operators. A direct field of application is within the maintenance spectrum. Having systems or machines capable of self-detecting or even self-repairing could represent a game-changer, in capital asset fields such as the mining industry in particular. This paper aims to investigate the possible benefits and challenges of self-engineering / self-maintenance concerning mining machines, specifically bucket-wheel ...self-engineering, self-maintenance, maintenance operations, mining industry, bucket-wheel excavator, gearbox revitalizationSteven Manders, Milorad Pantelić, Vladimir Milisavljević, Alberto Martinetti. "Self-Engineering: Possibilities for Maintenance Operations in the Mining Machines Industry" in SSRN Electronic Journal, Elsevier BV (2021). https://doi.org/10.2139/ssrn.3945979
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Present Situation and Alternative Water Supply Solutions for Northern Vojvodina (Serbia)
The northern part of the Autonomous Province of Vojvodina is situated in the central and southeastern sectors of the Pannonian Basin. Drinking water supply is provided by groundwater abstraction from depths of 60 to 200 m. The quality of that water is poor, especially due to high concentrations of arsenic which most water supply systems do not remove. Current planning documents call for the construction of large regional water supply schemes on the banks of the Danube and Tisa ...Bojan Hajdin, Vesna Ristić-Vakanjac, Dušan Polomčić. "Present Situation and Alternative Water Supply Solutions for Northern Vojvodina (Serbia)" in Proceedings of Bulgarian Academy of Sciences, "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences (2020). https://doi.org/10.7546/CRABS.2020.04.09
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The impact of the Covid-19 pandemic on the economy, water resources and sustainable development
Milan Tucaković, Dragoljub Bajić, Dušan Polomčić. "The impact of the Covid-19 pandemic on the economy, water resources and sustainable development" in The impact of the Covid-19 pandemic on the economy, resources and sustainable development, Megatrend univerzitet Beograd, Fakultet za menadžment Zaječar (2022)
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A contribution to the understanding of the discharge dynamics and water balance of the karst spring Gornji Dušnik (Suva Planina)
A sufficiently long time-series of daily discharges is needed to assess the discharge dynamics and calculate the water balance equation parameters of a spring (river source). The paper assumes that a catchment is gauged if a time-series of observations of at least 30 years is available, which is a rare case in Serbia. One-year monitoring is often set up to verify the reserves of a water source or spring intended for capture. Monitoring ceases after the final report is ...Aleksandar Tanasković, Vesna Ristić Vakanjac, Dušan Polomčić, Jelena Ratković. "A contribution to the understanding of the discharge dynamics and water balance of the karst spring Gornji Dušnik (Suva Planina)" in National Conference with International Participation “GEOSCIENCES 2023”, Review of the Bulgarian Geological Society, Sofia : Bulgarian Geological Society (2023)
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Laboratory testing of fly ash
Fly ash is one of the most common waste materials created by burning of coal. It is composed of smaller particles, consisting mainly of aluminosilicate glass, mullite and quartz, which are collected by electrostatic separators (filter) of gaseous products arising from the combustion of coal. This paper presents the pozzolanic properties, mechanical properties, chemical and mineral composition of fly ash obtained in the combustion process in a power plant Nikola Tesla A (PPNT A) with the addition of a ...chemical composition, fly ash, mechanical properties, mineral properties, pozzolanic properties, X-ray diffraction... ASTM C 618 [17] Characteristics Class Natural pozzolan F C N SiO2+Al2O3+Fe2O3 min (%) 70 50 70 SO3 max (%) 5 5 4 Humidity max (%) 3 3 3 Loss on ignition max (%) 6 6 10 Class F of fly ash is silicate, or silicate and aluminat material whose selfhardening effect is small or absent. In ...
... analyses of fly ash taken in S1 and S2 at location of PPNT A Chemical composition S1 S2 Mean values 1983 ÷ 2004 Ash composition, mass / % Loss on ignition 1000 °C 6,43 7,20 - SiO2 51,64 51,43 53,30 Al2O3 21,87 22,01 20,72 Fe2O3 5,54 6,03 7,23 CaO 1,05 1,16 8,74 MgO 3,01 2,83 2,64 SO3 ...
... create elements for road structures, but it must be taken into account that the embedding is done in segments, isolated from the influence of surface water and groundwater. Keywords: chemical composition; fly ash; mechanical properties; mineral properties; pozzolanic properties; X-ray diffraction ...Miloš Šešlija, Aleksandra Rosić, Nebojša Radović, Milinko Vasić, Mitar Đogo, Milovan Jotić. "Laboratory testing of fly ash" in Tehnički vijesnik (2016). https://doi.org/10.17559/TV-20150317171035
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Microstructural and magnetic properties of electrospun hematite/cuprospinel composites
Phase composition, microstructural and magnetic properties of electrospun hematite/cuprospinel composites were investigated. Samples were synthesized starting with 0 to 10 mol% of copper relative to iron. The round shape of reference electrospun fbres was preserved upon their heating up to 600 °C in air, whereas at 700 °C hollow substructure was additionally formed. In these reference samples the presence of hematite phase was detected by XRPD. A small amount (traces) of Fe3O4 /γ-Fe2O3 was also found, due to the ...Electrical and Electronic Engineering, Condensed Matter Physics, Atomic and Molecular Physics and Optics, Electronic, Optical and Magnetic MaterialsMira Ristić, Aleksandar Kremenović, Michael Reissner, Željka Petrović, Svetozar Musić. "Microstructural and magnetic properties of electrospun hematite/cuprospinel composites" in Journal of Materials Science: Materials in Electronics, Springer Science and Business Media LLC (2020). https://doi.org/10.1007/s10854-020-03526-0
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Classification of Terms on a Positive-Negative Feelings Polarity Scale Based on Emoticons
Mihailo Škorić (2017)The goal of this paper is to draw attention to the possibility of using emoticon-riddled text on the web in language-neutral sentiment analysis. It introduces several innovations in the existing framework of research and tests their effectiveness. It also presents a software tool especially made for that purpose, explains how it builds a database with sentimental value of terms and offers the user manual. Finally, it presents a software tool that tests the new database and gives some examples ...... on Based on Emoticons”, pp. 67–91 Under an assumption that reducing all possible parameters onto polar- ity, there isn’t a significant information loss and that the machine can decide between multiple choices using a single parameter, task is reduced to deter- mination of what is positive and what is ...
... options are activated by pressing the appropriate buttons located on the bottom of the screen (Figure 5). In both cases, due to possible irreversible data loss, the user will need to confirm the process in an additional dialog box that will appear on the screen. Once the user is satisfied with the settings ...Mihailo Škorić. "Classification of Terms on a Positive-Negative Feelings Polarity Scale Based on Emoticons" in Infotheca, Faculty of Philology, University of Belgrade (2017). https://doi.org/10.18485/infotheca.2017.17.1.4
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Mesozoic carbonate rocks in Serbia used as dimension stone
Vesna Matović, Tijana Vojnović Ćalić (2016)The building industry in Serbia uses, to a great extent, imported natural stone for architectural purposes. The significance of local deposits, particularly limestones, is not adequately perceived despite the country’s abundance of these valuable resources. Therefore, this study focuses on Serbia’s Mesozoic carbonate rocks, specifically on the deposits of four selected quarries: Klisura, Skrzut, Struganik, and Tisnica. The quality and prospects of the application of these limestones has not yet been the subject of a detailed, comprehensive investigation. Therefore, ...... bulk density (ZSP) and real density (ZBP); b porosity (P) and water absorption (Uv); c compressive strength-dry, water rudstone). They also have a low porosity (1.3—2.0 %). All limestones exhibit similar behaviour in terms of water absorption (Fig. 4b). Concerning porosity, these rocks have ...
... were 10-17 % lower in the water saturated samples, whereas after 25 freeze-thaw cycles they have decreased by 20-27 %. A small decrease in compressive strength of the Struganik limestone (after the frost test), compared to the expected decrease in strength in water saturated sam- ples, may ...
... may be due to the heterogeneity of the rock mass, 1.e., tested samples. All observed limestones are resistant to frost with the mass loss being less than 2 % after 25 freeze-thaw cycles. All investigated limestones are predominantly hard rocks (Bilbija and Matović 2009). They have equable saturated ...Vesna Matović, Tijana Vojnović Ćalić. "Mesozoic carbonate rocks in Serbia used as dimension stone" in Bulletin of Engineering Geology and the Environment, Springer Science and Business Media LLC (2016). https://doi.org/10.1007/s10064-015-0722-0
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Freeze-dried nanocrystal dispersion of novel deuterated pyrazoloquinolinone ligand (DK-I-56-1): Process parameters and lyoprotectant selection through the stability study
Jelena R. Mitrović, Maja Bjelošević Žiberna, Aleksandar Vukadinović, Daniel E. Knutson, Dishary Sharmin, Aleksandar Kremenović, Pegi Ahlin Grabnar, Odon Planinšek, Dominique Lunter, James M. Cook, Miroslav M. Savić, Snežana D. Savić (2023)Recently, nanocrystal dispersions have been considered as a promising formulation strategy to improve the bioavailability of the deuterated pyrazoloquinolinone ligand DK-I-56-1 (7‑methoxy-2-(4‑methoxy-d3-phenyl)-2,5-dihydro-3H-pyrazolo[4,3-c]quinolin-3-one). In the current study, the freeze-drying process (formulation and process parameters) was investigated to improve the storage stability of the previously developed formulation. Different combinations of lyoprotectant (sucrose or trehalose) and bulking agent (mannitol) were varied while formulations were freeze-dried under two conditions (primary drying at -10 or -45 °C). The obtained lyophilizates were characterized in terms ...... During primary drying, sublimation of water leads to the disintegration of the stabilizer layer of the nanoparticles, resulting in aggregation of the particles. Lyoprotectants stabilize nanoparticles by replacing the hydrogen bonds of water, as explained by the water replacement hypothesis (Trenkenschuh ...
... formulations were dispersed in ultrapure water to achieve the same concentration of DK-I-56-1 as in the dispersion before lyophilization, by manual shaking for maximum 30 s. Before measurement, the nanocrystal dispersions were diluted in ultrapure water (1:100, v/v). Reconstitution and particle ...
... ing to the stretch vibration of the two crystal water molecules in the dihydrate, disappeared in the spectra of the freeze-dried samples, similarly as in Jakubowska et al. (2022) (Fig. 7b). In addition, the peak associated with the crystal water in the trehalose dihydrate at 1680 cm ! shifted ...Jelena R. Mitrović, Maja Bjelošević Žiberna, Aleksandar Vukadinović, Daniel E. Knutson, Dishary Sharmin, Aleksandar Kremenović, Pegi Ahlin Grabnar, Odon Planinšek, Dominique Lunter, James M. Cook, Miroslav M. Savić, Snežana D. Savić. "Freeze-dried nanocrystal dispersion of novel deuterated pyrazoloquinolinone ligand (DK-I-56-1): Process parameters and lyoprotectant selection through the stability study" in European Journal of Pharmaceutical Sciences, Elsevier BV (2023). https://doi.org/10.1016/j.ejps.2023.106557
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Održiva eksploatacija izvorišta mineralnih voda na primeru Vrnjačke banje
Vladimir Živanović, Veselin Dragišić, Sava Magazinović, Jakov Andrijašević, Nebojša Atanacković (2022)Jedna od najznačajnijih i najposećenijih banja u Srbiji je Vrnjačka Banja koja je poznata po bogatstvu i dugoj istoriji korišćenja mineralnih voda. Obimna hidrogeološka istraživanja izvedena proteklih nekoliko decenija ukazala su na ograničenost rezervi mineralnih voda u uslovima dosta složene hidrogeološke građe područja pojavljivanja. Poslednjih godina eksploatacija ovog dragocenog resursa zadobija novu dimenziju, naročito nakon privatizacije pojedinih hotelskih kompleksa kada se povećavaju potrebe za mineralnim vodama i od kada počinje izrada novih vodozahvata što dovodi u pitanje održivu eksploataciju ...mineralne vode, izvorišta mineralnih voda, održivo korišćenje mineralnih voda, monitoring mineralnih voda, Vrnjačka BanjaVladimir Živanović, Veselin Dragišić, Sava Magazinović, Jakov Andrijašević, Nebojša Atanacković. "Održiva eksploatacija izvorišta mineralnih voda na primeru Vrnjačke banje" in Zbornik radova XVI srpskog Simpozijum o hidrogeologiji sa međunarodnim učešćem, Univerzitet u Beograd, Rudarsko-geološki fakultet (2022)
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A Description of Morphological Features of Serbian: a Revision using Feature System Declaration
In this paper we discuss some well-known morphological descriptions used in various projects and applications (most notably MULTEXT-East and Unitex) and illustrate the encountered problems on Serbian. We have spotted four groups of problems: the lack of a value for an existing category, the lack of a category, the interdependence of values and categories lacking some description, and the lack of a support for some types of categories. At the same time, various descriptions often describe exactly the same ...... attributes or attribute values, explicit statement of valid combinations of attribute and values. We expect that our description will transform without loss of information in the new version of MULTEXT-East format. 7. References Courtois, B. and Silberztein, M. (eds.) (1990). Dictionnaires électroniques ...Cvetana Krstev, Ranka Stanković, Vitas Duško. "A Description of Morphological Features of Serbian: a Revision using Feature System Declaration" in Proceedings of the 5th International Conference on Language Resources and Evaluation, LREC 2010, Valetta, Malta : European Language Resources Association (2010)
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Conversion of land areas after coal mine closure and reclamation
Otkopavanje uglja površinski i podzemno praćeno je degradacijom zemljišta, promenom formiranja predela i izmenom flore i faune. Od velikog značaja je razvoj novih naučno utemeljenih pristupa obnovljanje antropogeno poremećenih predela zasnovanih na formiranju rekultivacionih i rudarskih tehnologija. Apsolutno je neophodno obezbediti sveobuhvatno kvalitetno očuvanje zemljišnih i vodnih resursa i odrediti rekultivisano zemljište za novu namenu. U ovom članku je dat pregled najpopularnijih metoda rekultivacije zemljišta i mogućnosti rekultivacije zemljišta nakon završetka rekultivacije i zatvaranja rudnika uglja.... the degradation of agricultural lands. Predictions of the effects on the environment are very important and present the concern in the sense of the loss of surface area and space for living. The study on the environment has a basic description of the effects that are expected, and it is a basic document ...
... on the formation of reclamation and mining technologies. t is absolutely necessary to ensure the comprehensive quality preservation of land and water resources and to designate reclaimed land for a new purpose. This article presents an overview of the ranking most popular methods of land recultivation ...Radmila Gaćina, Bojan Dimitrijević, Sanja Bajić. "Conversion of land areas after coal mine closure and reclamation" in 9th International conference mining and environmental protection MEP 23 Proceedings, Sokobanja, 24-27.05.2023., Belgrade : University of Belgrade - Faculty of mining and geology (2023)
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Groundwater gravitational circulation of Karst Veliko Vrelo and Malo Vrelo springs by isotope and the noble gas method: case study of the Beljanica Massif
Earth-Surface Processes, Geology, Pollution, Soil Science, Water Science and Technology, Environmental ChemistryLjiljana Vasić, Laszlo Palcsu, Huang Fen. "Groundwater gravitational circulation of Karst Veliko Vrelo and Malo Vrelo springs by isotope and the noble gas method: case study of the Beljanica Massif" in Environmental Earth Sciences, Springer Science and Business Media LLC (2019). https://doi.org/10.1007/s12665-019-8294-0
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Analiza sistema odvodnjavanja površinskog kopa Drmno od podzemnih voda sa severnim savršenim ekranom
Izrada nesavršenog ekrana do drugog sloja uglja na površinskom kopu Drmno, pored zadržavanja postojećih standardnih metoda odvodnjavanja od podzemnih voda linijama bunara, predviđena je poslednje decenije u celokupnoj rudarskoj projektnoj dokumentaciji. Iz objektivnih i subjektivnih razloga njegova realizacija nije ostvarena do danas. U međuvremenu je, uz dodatna geološka istraživanja i promenu dinamike i parametara sistema površinske eksploatacije, došlo do određenih značajnih prostornih promena geoloških i rudarskih uslova u eksploatacionom polju. Ovo je omogućilo preliminarno inoviranje pristupa procesu i konceptu ...Tomislav Šubaranović, Dušan Polomčić, Vladimir Pavlović. "Analiza sistema odvodnjavanja površinskog kopa Drmno od podzemnih voda sa severnim savršenim ekranom" in Zbornik apstrakata sa 9. Međunarodne konferencije Ugalj, Zlatibor, 2019., Jugoslovenski komitet za površinsku eksploataciju (2019)
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Ecological status of the Lim river alluvium in Serbia
Amel Kurbegović, Boris Vakanjac, Vesna Ristić Vakanjac, Mirjana Bartula, Zorana Naunović, Nikola Milovanović, Jovan Kovačević (2022)Three countries share the catchment of the Lim River and they have been engaged in an eco-logical struggle for years, to conserve the river, its tributaries, and biodiversity. Honoring international conventions and declarations, along with active involvement of the civil society and support of Eu-ropean Union agencies, major efforts are being made to draw attention to the degradation of nature, especially water, which is essential for life on the planet Earth. Considering that natural resources are limited and that ...Amel Kurbegović, Boris Vakanjac, Vesna Ristić Vakanjac, Mirjana Bartula, Zorana Naunović, Nikola Milovanović, Jovan Kovačević. "Ecological status of the Lim river alluvium in Serbia" in Fresenius Environmental Bulletin, Parlar Scientific Publications (2022)
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Turbidity simulation for short-term prediction: case study of the karst spring Surdup (Bor, Serbia)
Из перспективе снабдевања пијаћом водом, квалитет воде карстних издани је међу највишим, и често захтева само њихову дезинфекцију пре употребе. Међутим, карстне подземне воде изложене су одређеним притисцима. Током сушних периода углавном има мало воде, а током кишних периода има изненадних променa и квалитета и количине воде. Реакција слива на падавине је често брза и варијације у параметрима квалитета и квантитета (истицање, ниво вода, замућеност, укупан број микроорганизама, суспендовани нанос, итд.) су нестабилни. Ово захтева праћење истицања и ...Marina Pešić, Vesna Ristić Vakanjac, Boris Vakanjac, Kostadin Jovanov. "Turbidity simulation for short-term prediction: case study of the karst spring Surdup (Bor, Serbia)" in Comptes rendus de l'Academie bulgare des Sciences, Bulgarian academy of science (2016)
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VENTEX: An Expert System for Mine Ventilation Systems Analysis
Analiza sistema za ventilaciju je komleksan proces, koji bazira na proračunu brojnih parametara, koji se odnose na: stanje mreže, provetrenost, stabilnost sistema, gubitke vazduha, klimatske uslove, gasno stanje, ugroženost od požara i opasne prašine. Navedeni problemi se uspešno rešavaju paketom SimVent, ali potpuno razumevanje i korišćenje dobijenih rezultata zahteva angažovanje iskusnog specijaliste iz oblasti ventilacije. Rešenje je nađeno u kreiranju ekspertnog sistema VENTEX, čija je baza znanja formalizacija ekspertskog znanja iz oblasti ventilacije rudnika. U radu je prikazana metodologija ...... according to their relevance into the following categories: the ventilation network, aeration of the mine, stability of the ventilation system, air loss, climate conditions, mine gas state, fire risk and harmful dust risk. Once the parameter values are obtained the estimation process for the general ...Ranka Stanković, Nikola Lilić, Ivan Obradović. "VENTEX: An Expert System for Mine Ventilation Systems Analysis" in YU Info '96 Brezovica, Društvo za informacione sisteme i računarske mreže (1996)