101 research outputs found
Modeling of the influential parameters for the ranking of the technological processes of pyrometalurgical copper extraction by using multiple-criteria analysis
Ова докторска дисертација има за циљ формирање нумеричког модела за
рангирање и селекцију комплексних технолошких процеса на основу њихових
утицајних параметара. У полазним поглављима ове дисертације дата је анализа
најзначајнијих литературних извора који су имали највећи утицај приликом
њене израде, а ткође се дефинишe предмет и циљеви истраживања. Следећа
поглавља се баве анализом теоријског значаја нумеричког моделовања као и
применом код технолошких система. У наредном делу овог рада стављен је
фокус на анализу и примену метода вишекритеријумског одлучивања где се кроз
одговарајући литературни преглед сагледава примена ових метода на различите
технолошке системе. Посебна пажња усмерена је на моделовање технолошких
процеса за пирометалуршку екстракцију бакра и кроз посебно поглавље дат је
опис најзначајнијих технолошких процеса као и карактеристика утицајних
параметара. Након тога, применом методе вишекритеријумског одлучивања,
засновано на PROMETHEE II методи, извршено је рангирање и селекција
технолошких процеса за пирометалуршку екстракцију бакра, док је коришћењем
AHP-TOPSIS методе извршена верификација добијеног модела. У завршном
делу рада дата је примена овог модела на конкретним топионицама где су
добијени конкретни закључци.
Резултат ове дисертације јесте развој вишекритеријумског модела којим
се унапређује процес одлучивања у технолошким системима. Овај модел
омогућава доносиоцима одлука да донесу информативне одлуке и постигну
оптималне резултате у компексним условима. Стога, овај модел пружа
могућност одабира не најбољег технолошког процеса, већ оног који ће се
најбоље применити у датим условима.This doctoral dissertation aims to form a numerical model for the ranking and
selection of the complex technological processes based on their influential parameters.
The main chapters of this dissertation provide an analysis of the most important literary
sources that have had the greatest influence in its development, and define the subject
and the objectives of the research.The following chapters deal with the analysis of the
theoretical significance of numerical modeling, and the application of technological
systems. In the next part of this paper, the focus was placed on the analysis and
application of multicriterial decision-making methods, where the application of these
methods to different technological systems is considered by means of the appropriate
literature review. Particular attention is paid to the modeling of technological processes
for pyrometallurgical copper extraction, where a special chapter provides a description
of the most important technological processes, as well as of the characteristics of the
influential parameters. Subsequently, by using the multi-criteria decision method
based on the PROMETHEE II method, the ranking and the selection of the
technological processes for pyrometallurgical copper extraction was carried out, and
the verification of the obtained model was then performed using the AHP-TOPSIS
method. In the final part of this paper, the application of this model was carried out in
the particular smeltery, and specific conclusions were obtained.
The result of this disertation is the development of a multi-criteria model that
improves the decision-making process in technological systems. This model allows
the decision makers to make informative decisions and achieve optimum results in
compex conditions. Therefore, this model offers the ability to choose not the best
technological process, but the one that will be best applied in the given conditions
Interrelationships between grain nitrogen content and other indicators of nitrogen accumulation and utilization efficiency in wheat plants
The topic of N wheat nutrition was prevalent during the last decades of the 20th century for many reasons such as energy crises, profitability of small grain production, and ecosystem protection and preservation. The objective of this study was to determine the interrelationships between wheat (Triticum aestivum L.) grain N content and other indicators of N nutrition efficiency to better understand the N nutrition process in wheat plants. The experiment included 30 wheat cultivars and experimental lines from Serbia. Plant samples of each genotype were taken at anthesis and maturity. The following parameters related to N accumulation and translocation within the wheat plant were calculated: N content (at anthesis, grain, straw, and total at maturity), N harvest index (NHI), N reutilization (N reU), and N lost (-) or gained (N post-anthesis). Our results showed that N content in the aboveground part of the plant expressed very strong direct positive effects on N yield (phenotypic coefficient 3.78** to 9.34** and genotypic coefficient 1.43** to 2.32**), while its indirect effects varied. The influence of independent variables on grain N content has been changing from year to year in a negative way. Total N accumulation (N total) had the highest negative direct effect in the first year of the study (phenotypic coefficient -2.11**), N total in the second (phenotypic coefficient -2.78**), and N reutilization in the third (phenotypic coefficient -8.49**). Genotypic coefficients indicate that the most frequent strong direct negative effect was N reutilization (-0.47** and -0.99** in the first 2 yr of research, respectively). Nitrogen reutilization and its current assimilation are very important and related to grain N supply processes. Their interaction leads to the conclusion that forming N yield is a very complex mechanism and, as a result, grain yield and quality. The abovementioned parameters could be considered as important criteria in wheat breeding to improve production efficiency and reduce adverse impacts of N fertilizers on the ecosystem
Fly-Through animation at the Faculty of Technical Sciences in Novi Sad
U ovom radu je dat pregled korišćenja Fly Through animacije, posebno u arhitekturi. Specijalno je prikazana primena ove animacije na studijama Računarske grafike-Animacija u inženjerstvu i na studijama Arhitekture i urbanizma, na Fakultetu tehničkih nauka u Novom Sadu. Prikazana su tri istorijski značajna objekta: Gimnazija Jovan Jovanović Zmaj, Departman za Arhitekturu i urbanizam, kao i gradska kuća u Novom Sadu, na čijim modelima su urađene animacije. Postupak izrade ovih animacija je detaljno opisan, redom, kako su objekti i animacije napravljeni.This article describes application of Fly-Through animation, especially in architecture. It shows application of this animation technique on Computer Graphics - Animation in Engineering studies and on Architecture and Urban Planning studies at the Faculty of Technical Sciences in Novi Sad. Three historically significant buildings have been modeled and animated: Gymnasium Jovan Jovanovic Zmaj, Department of Architecture and Urban Planning and a City Hall in Novi Sad. Development process of these models and animations is described in details, step by step
Weed infestation and biodiversity of winter wheat under the effect of long-term crop rotation
The paper presents the study of the floristic composition of weeds and weed infestation in winter wheat in long-term crop rotations at the experimental station near Novi Sad (Serbia). During the study period, a total of 48 weed species were determined, out of which 33 were determined in each study year. In two study years, there were 18 common species, while 15 species determined in 1991 were not found 19 years later. On the other hand, the study in 2010 recorded 15 new species that had not been previously found. The greatest floristic diversity (20 species) was found on fertilized four-year rotation in 1991 and unfertilized two-year rotation in 2010. The lowest diversity was recorded in 2010 on fertilized four-year rotation (9 species) and fertilized three-year rotation (10 species). The highest weed infestation was recorded in 1991 on unfertilized two-year rotation (2963 plants m(-2)) and unfertilized three-year rotation (2126 plants m(-2)), which is statistically significant compared to other variants. The lowest average weed infestation was observed in 2010 on fertilized three-year rotation (40 plants m(-2)) and fertilized four-year rotation (53 plants m(-2)). Long-term crop rotations have a significant effect on the floristic composition and structure of weeds in winter wheat
Cryptanalysis of Round-Reduced LED
In this paper we present known-plaintext single-key and chosen-key attacks on round-reduced LED-64 and LED-128.
We show that with an application of the recently proposed slidex attacks,
one immediately improves the complexity of the previous single-key 4-step attack on LED-128. Further, we explore the possibility of
multicollisions and show single-key attacks on 6 steps of LED-128. A generalization of our multicollision attack
leads to the statement that no 6-round cipher with two subkeys that alternate, or 2-round cipher with
linearly dependent subkeys, is secure in the single-key model. Next, we exploit the possibility of finding pairs of inputs that follow
a certain differential rather than a differential characteristic, and obtain chosen-key differential distinguishers
for 5-step LED-64, as well as 8-step and 9-step LED-128. We provide examples of inputs that follow the 8-step differential,
i.e. we are able to practically confirm our results on 2/3 of the steps of LED-128. We introduce a new type of
chosen-key differential distinguisher, called random-difference distinguisher, and
successfully penetrate 10 of the total 12 steps of LED-128. We show that this type of attack is generic
in the chosen-key model, and can be applied to any 10-round cipher with two alternating subkeys
Distinguisher and Related-Key Attack on the Full AES-256 (Extended Version)
In this paper we construct a chosen-key distinguisher and a
related-key attack on the full 256-bit key AES. We define a
notion of {\em differential -multicollision} and show that for
AES-256 -multicollisions can be constructed in time and with negligible memory, while we prove that the same
task for an ideal cipher of the same block size would require at
least time. Using similar
approach and with the same complexity we can also construct
-pseudo collisions for AES-256 in Davies-Meyer hashing mode, a
scheme which is provably secure in the ideal-cipher model. We have
also computed partial -multicollisions in time
on a PC to verify our results. These results show that AES-256 can
not model an ideal cipher in theoretical constructions.
Finally, we extend our results
to find the first publicly known attack on the full 14-round
AES-256: a related-key distinguisher which works for one out of
every keys with data and time complexity and
negligible memory. This distinguisher is translated into a
key-recovery
attack with total complexity of time and memory
Examples of differential multicollisions for 13 and 14 rounds of AES-256
Here we present practical differential -multicollisions for AES-256, which can be tested on any implementation of AES-256. In our paper Distinguisher and Related-Key Attack on the Full AES-256 -multicollisions are found with complexity . We relax conditions on the plaintext
difference allowing some bytes to vary and find multicollisions for 13 and 14 round AES with complexity .
Even with the relaxation there is still a large complexity gap between our algorithm and the lower bound that we have proved in Lemma 1. Moreover we believe that in practice finding even
two fixed-difference collisions for a good cipher would be very challenging
Dinamika slanog morskog jezera (Veliko jezero, Mljet, Jadran) zabilježena pri mjerenjima temperature mora
This paper describes hydrographic and dynamic conditions in the Mljet lakes, through the analysis of high-frequency temperature measurements carried out at an intermediate layer of Big Lake (BL) and Soline Channel during two years (December 2005-October 2007). It appears that the lakes may be colder than the open sea during wintertime by as much as 2-3°C and warmer at the surface during summer by as much as 4°C. Several interesting processes were captured within the series of which we investigated the wintertime cooling that occurred in 2006, diurnal and semidiurnal temperature changes driven by the tides within the connecting channel and the occurrence of turbulence in BL close to the connecting channel. The latter seems to have large implications for the thermocline/pycnocline deepening during the summertime, as incoming open ocean waters are much denser than the BL waters.Rad opisuje termohalina i dinamička svojstva mljetskih jezera, temeljem analize visokofrekventnih mjerenja temperature obavljanih u intermedijarnom sloju Velikog jezera i kanalu Soline tijekom dvije godine (prosinac 2005. – listopad 2007.). Mjerenja ukazuju da je temperatura jezera niža od temperature otvorenog mora za oko 2-3 o C tijekom zimskih mjeseci, dok je tijekom ljeta viša oko 4oC u površinskom sloju. Nekoliko zanimljivih oceanografskih procesa je zabilježeno na mjerenjima,
od kojih je istraženo hlađenje jezera tijekom zime 2006. godine, dnevne i poludnevne promjene temperature pobuđene plimotvornom silom, te pojava turbulencije u području Velikog jezera
bližem kanalu Soline. Mjerenja su ukazala na činjenicu da turbulencija uzrokuje izrazito vertikalno miješanje i poniranje termokline i piknokline za vrijeme ljetnih mjeseci u površinskom i intermedijarnom sloju Velikog jezera, jer vode otvorenog mora posjeduju višu gustoću od voda jezera
Rural NEETs report in Serbia: 2009/2019 Overview
The situation of rural Youths Neither in Employment nor in Education or Training (NEET) aged between 15 and 34 years old, over the last decade (2010-2019) in Serbia is presented in this report. The main criterion for analysis was the degree of urbanisation, where the comparison was done between rural areas, towns and suburbs, cities, and the whole country. The data available on EUROSTAT and the national Statistical office of Serbia were used as main resources for statistical interpretation. The statistical procedures used in the report rely on descriptive longitudinal analysis, using graphical displays (e.g. overlay line charts) as well as the calculation of proportional absolute and relative changes between observed years. The analysis of the youth population in Serbia aged 15-24 years in total as well as the youth population for different degrees of urbaisation, for the period 2010-2019, showed a decreasing trend. In the period 2014-2019 (which is with available data for the case of Serbia) it can be observed that the youth employment rate is increasing in all areas of urbanisation. In contrast to the employment, the level of unemployment in Serbia is constantly decreasing in the period 2014-2019. This trend is similar for all three areas of urbanisation. The decrease in the number of early school leavers is registered in the case of entire Serbia, cities, and rural areas. The only trend of increasing of early school leavers’ rate is recorded for the towns and suburbs, for the observed period 2014-2019. In the period 2010-2019, the NEET rate is declining in Serbia for all three degrees of urbanisation. In comparison to EU countries, Serbia is still significantly above the European average, but with a tendency of reducing the gap
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