Uticaj hraniva na dužinski rast dužičaste pastrmke (Oncorhynchus mykiss, Walbaum, 1792) gajene u kavezima

The experiment was carried out at the cage farm “Tropic ribarstvo” (reservoir lake Bocac, 50km far from Banja Luka) in two cycles with 6 treatments and 90 days per cycle (180 days). The aim of the experiment was to analyze the effect of feed type on the length growth of rainbow trout reared in cages. All applied feed types had no significant effect on the mean length growth during autumn and winter probably due to the decrease of water temperature and level of feeding that was justified by a low length growth rate of individuals. Feed with higher content of row fat had a optimal effect on mean body length in spring and summer and showed significant differences of mean body length ( = 0.05; = 0.01) compared to treatment 1 that had a lower fat and higher carbohydrate content. There was no significant difference between the mean length growth of rainbow trout using feed with 22 and 26 % of fat. Analyzing the season in relation to the feed type (F test) a very significant difference of mean body length was confirmed ( = 0.01), showing that the body length is highly dependent on the season and the feed type

Interconnection Contracts between Service and Content Provider with Partial Cloud Migration

This paper addresses interconnection contracts in content provisioning scheme with partial cloud migration. Model for traffic workload of such scheme based on content popularity factor is introduced. Monte Carlo simulation for bandwidth demand estimation is used. Cost analysis of content provider's resources utilization regarding average requests' rejection rate is observed. The performance analysis of content provider's incentive for partial cloud migration is applied. Three interconnection contracts are analysed: Revenue Sharing, Cost Sharing and Wholesale Price contract. Obtained results show that partial cloud migration can reduce both content provider's costs and average requests' rejection rate. Under observed constellation, Revenue Sharing contract may represent satisfying solution for both providers

Influence of pH on element leaching from plastic and glass bottles into water

Monitoring of elemental composition in bottled waters is essential to assess both their nutritional contribution and potential health risks. In this study, six widely consumed Serbian bottled waters were analyzed to evaluate the influence of packaging material (PET vs. glass) and storage temperature (–20°C, 25°C, 40°C) on elemental stability [1,2]. A total of 18 elements were quantified by ICP–MS, and variations were compared across brands and conditions. The results revealed clear differences between PET and glass packaging. Antimony, originating from PET, was consistently higher in plastic bottles, with the maximum value of 15.6 μg/L detected in Knjaz Miloš at 40 °C. This level exceeded the drinking water guideline of 5 μg/L, while all glass samples remained below the limit. Cd and Pb showed sporadic occurrences, with maximum concentrations of 0.50 μg/L and 1.98 μg/L, respectively, both remaining within regulatory safety thresholds. Independent of packaging, each brand showed a unique geochemical fingerprint. Knjaz Miloš was distinguished by exceptionally high levels of strontium (up to 801 μg/L) and lithium (695 μg/L), in contrast to Rosa, which contained the lowest values of these elements. These markers proved stable across a range of temperatures, reflecting the geological origin of the source rather than packaging effects. pH values ranged between 5.9 and 6.9 for all PET samples and were nearly identical in the corresponding glass samples, indicating that pH had no significant influence on elemental migration. However, elevated temperatures enhanced Sb leaching from PET, confirming temperature as the dominant factor affecting packaging-related contamination

Mogućnosti primene frakcionog računa u modelovanju telekomunikacionog saobraćaja / Possibility of fractional calculus application for telecommunication traffic modelling / Возможность применения метода дробной производной при моделировании телекоммуникационного трафика

Frakcioni račun je oblast matematičke analize koja se bavi izučavanjem i primenom izvoda i integrala proizvoljnog reda. Ovom teorijom bavili su se mnogi poznati matematičari među kojima su Ojler, Riman, Liuvil, Abel i Furije. Predloženo je više definicija za izračunavanje izvoda i integrala necelog reda. U ovom radu daje se pregled nekih predloženih definicija, kao i osnovne postavke frakcionog računa sa posebnim naglaskom na mogućnostima njegove primene u domenu modelovanja telekomunikacionog saobraćaja. Činjenica je da frakcioni račun poslednjih decenija nalazi sve veću primenu u raznim naučnim oblastima. Modeli zasnovani na frakcionom računu pokazali su se korisnim u fizici, mehanici, elektrotehnici, biohemiji, medicini, ekonomiji, teoriji verovatnoće. U ovom radu analizira se mogućnost primene frakcionog računa u modelovanju telekomunikacionog saobraćaja. Istraživanja pokazuju da se karakteristike telekomunikacionog saobraćaja na lokalnom i globalnom nivou u mreži, kao što su samosličnost i zavisnost u dugom opsegu, efikasnije mogu opisati pomoću frakcionog računa umesto konvencionalnih stohastičkih procesa. U radu su prikazani predloženi modeli zasnovani na frakcionom računu koji modeluju fenomene prisutne u savremenim telekomunikacionim mrežama. / Fractional calculus is a field of mathematical analysis concerned with research and application of derivatives and integrals of an arbitrary order. Many famous mathematicians studied the theory of fractional calculus such as Euler, Riemann, Liouville, Abel, Fourier and others. There are many proposed definitions for calculating derivatives and integrals of non-integer order. In this paper, several proposed definitions along with basic statements of fractional calculus are presented with an emphasis on a possibility of fractional calculus application in telecommunication traffic modelling. The fact is that fractional calculus is widely used in various scientific disciplines in recent decades. Models based on fractional calculus have proved to be very useful in physics, mechanics, electrical engineering, biochemistry, medicine, economy, and probability theory. This paper analyses a possibility of application of fractional calculus for modelling telecommunication traffic. Many research studies have shown that traffic characteristics at a local and global level, such as self-similarity and long range dependence, can efficiently be described by fractional calculus instead of using conventional stochastic processes. Some proposed models based on fractional calculus that describe phenomena present in modern telecommunication networks are presented in this paper. / Дробная производная (или производная дробного порядка) является обобщением математического понятия производной. Существует несколько разных способов обобщить это понятие, но все они совпадают с понятием обычной производной в случае натурального порядка. Данной проблемой занимались многие известные математики, среди которых Эйлер, Риман, Лиувилль, Абель и Фурье. В данной статье приведен обзор некоторых определений, наряду с основными положениями дробного исчисления, которые представлены с акцентом на возможность применения данного метода при моделировании телекоммуникационного трафика. Дело в том, что метод производной дробного порядка, нашел широкое применение в различных областях науки. Модели, основанные на данном методе, оказались востребованными в физике, механике, электротехнике, биохимии, медицине, экономике, а также в теории вероятности. В данной статье мы анализируем возможность применения метода производной дробного порядка для моделирования телекоммуникационного трафика. Исследования показывают, что характеристики телекоммуникационного трафика в сети на локальном и глобальном уровнях, а также самоподобие и зависимость в широком диапазоне, могут быть эффективно описаны с помощью метода дробной производной, вместо обычной модели мультипликативного стохастического каскада. В данной статье представлены предлагаемые модели, основанные на методе дробной производной, воспроизводящие явления, присутствующие в современных телекоммуникационных сетях

Overview of the auction mechanisms for pricing and allocation of the cloud provider’s resources

Comprehensive development of cloud computing requires improvement of appropriate mechanisms for cloud provider’s resource allocation and pricing. Considering the characteristics of cloud resources and the fact that demand for cloud resources is not uniform, dynamic mechanisms for resource allocation and pricing are needed. The aims of dynamic mechanisms are optimization of resources’ utilization and revenue maximization of cloud providers, as well as prices minimization for cloud customers. It appears that some auction model can be vary efficient since resources are allocated to the customers that value them the most, and prices are determinated depending on the supply and demand conditions. Combinatorial auctions, double auctions and their combination are most often used for cloud resources’ allocation and pricing. In this paper, the overview of some proposed auction models is provided