Vol. 7 No. 1 (2017)

Open Access Original Scientific Paper

GAM MODEL AND TOURIST VALORIZATION OF GEOSITES PLOČNIK

by Miroslav Stanković, Stefan Milovanović

In Serbia, there are several sites from the Neolithic period, but there is only one site from the period of existence of the Vinča-Tordoš family (5500-4800 BC). In this paper, we will try to become familiar with the site named Pločnik by using two methods. This site is one of many archeological sites in Serbia, but it stands out uniquely because it is under state protection. The methods to be applied are GAM model and tourist valorization.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-14161 Published: 18 Jul 2017

Open Access Original Scientific Paper

DETERMINATION OF ACCELERATED FACTORS IN GRADIENT DESCENT ITERATIONS BASED ON TAYLOR’S SERIES

by Milena Petrović, Nataša Kontrec, Stefan Panić

In this paper the efficiency of accelerated gradient descent methods regarding the way of determination of accelerated factor is considered. Due to the previous researches we assert that the use of Taylor’s series of posed gradient descent iteration in calculation of accelerated parameter gives better final results than some other choices. We give a comparative analysis of efficiency of several methods with different approaches in obtaining accelerated parameter. According to the achieved results of numerical experiments we make a conclusion about the one of the most optimal way in defining accelerated parameter in accelerated gradient descent schemes.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-14337 Published: 17 Jul 2017

Open Access Original Scientific Paper

ANALISYS OF THE INFLUENCE OF COMMUNICATION PARAMETERS OF FSO CHANNELS ON THE RECEPTION QUALITY

by Aleksandar Marković, Stefan Panić, Branimir Jakšić, Petar Spalević, Marko Smilić

In this paper, the signal transmission in the Free-Space Optics (FSO) communication system using the software package OptiSystem 7.0 is analyzed. The influence of parameters FSO (Free-Space-Optics) channels (Range, Attenuation, Beam Divergence, Transmitter Loss, Receiver Loss, and Additional Losses) on the reception quality is considered. The reception quality is analyzed according to the values of BER (Bit Error Ratio) and Q factor. Graphics and tables of the changes of BER and Q factor depending on the parameters of FSO are given. Also, the eye diagrams for the characteristic parameter values are given.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-14156 Published: 16 Jul 2017

Open Access Original Scientific Paper

AN ANALYSIS OF FACTORS AFFECTING THE HIGH RADON CONCENTRATION IN DIFFERENT TYPES OF HOUSES

by Ljiljana Gulan

This paper presents an analysis of indoor radon measurements carried out in municipality of Zubin Potok, northwestern part of Kosovo and Metohija. Annual measurements in two rooms of each house were performed by solid state nuclear track detectors commercially known as Gammadata. Average indoor radon concentration in different type of houses varied from 29-326 Bq/m3. A different year of house’s construction including various types of building materials were selected for survey. A detail analysis showed that the differences in radon concentration occur between various building materials used for construction, flooring level, type of room and behavior of inhabitants. It was found that building materials in some houses contribute additionally to indoor radon.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-13753 Published: 16 Jul 2017

Open Access Original Scientific Paper

DEVELOPMENT AND APPLICATION OF POTENTIOMETRIC STRIPPING ANALYSIS

by Ljiljana M Babincev, Dejan M Gurešić, Ranko M Simonović

This paper focuses on the voltammetric determination of lead, cadmium and zinc in water. Two ways of determining were investigated: individually and all three metals simultaneously. The experiments were performed using the Potentiometric Stripping Analysis (PSA). Determination of metals in real samples was preceded by preliminary tests. Preliminary investigations were performed in order to determine the optimal conditions of measurement. It was concluded that the process of determining was for most part influenced by: pH, time of metals extraction, stirring rate of the solution and the thickness of the mercury layer on the working electrode. The smallest concentrations of metals which can be determined using this method are: for lead 22.48 μg dm-3, for cadmium 16.23 μg dm-3 and for zinc 18.75 μg dm-3. The obtained results deviated from the actual 1.12% for lead, 1.91% for cadmium and 1.81% for zinc. All tests (individually and simultaneously) were conducted from model solution with concentration as follows: 44.96 μg dm-3 for lead, 32.47 μg dm-3 for cadmium and 37.50 μg dm-3 for zinc. The results of individual measurements deviated by 1.02% lead, 1.90% for cadmium and 1.89% for zinc. Simultaneously the contents were lower than real for: −4.58% for lead, cadmium for −1.91% and −1.89% for zinc. For the conditions determined, except for lead, deviations did not exceed ±2%. This indicates that Potentiometric Stripping Analysis is a good way of individual and simultaneous determination of lead, cadmium and zinc and for determination of their concentrations in water (river and groundwater).

picture_as_pdf View Full-Text DOI 10.5937/univtho7-13649 Published: 15 Jul 2017

Open Access Review Paper

CAVE MOTH AND BUTTERFLY FAUNA (Insecta: Lepidoptera) OF SERBIA: CURRENT STATE AND FUTURE PROSPECTS

by Predrag Jakšić

A history of the study of Lepidoptera in caves in Serbia is given. On this basis, a comparative analysis with Lepidoptera species in neighboring countries – Croatia, Romania and Bulgaria, was carried out. The presence of cavernicolous habitats and ecological niches suitable for Lepidoptera was investigated. There is a need to investigate these groups of organisms in Serbia and it is suggested that caves in Serbia be a priority in this research.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-14038 Published: 10 Jul 2017

Open Access Review Paper

THE CIRCADIAN CLOCK AND HUMAN ATHLETIC PERFORMANCE

by Biljana Vitošević

The importance of circadian clock in managing of key muscle physiological processes, and therefore the impact on athletic performance is well studied. Specifically chronobiology examines the mechanisms of the biological clock and the consequences of disrupting its rhythm. Although a body of literature indicates that the peak performance of notable indicators of athletic performance exerts mainly in the afternoon and evening hours which is attributed to increased temperature of the body, certain variables such as vigilance, alertness and cognitive domains can influence the shift of the peak performance during the day. In addition, athletes face issues of desynchronization of their circadian rhythm during frequent transcontinental travels, since their performance is reduced and the adjustment of the biological clock requires some recommendations in the training process and behavioral approach. This review focuses on some current studies on endogenous and exogenous factors which affect the circadian rhythm in order to achieve better sport results, evaluation of the impact chronotype through chronometric tests and revising more valuable determinants of sport performance, as well as the application of new mathematical models in individual treatment of recovery of athletes in the phase of resynchronization.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-13650 Published: 30 Jun 2017

Open Access Original Scientific Paper

SYNTHESIS AND SPECTROSCOPIC CHARACTERIZATION OF LITHIUM SALTS OF COPPER(II) AND NICKEL(II) COMPLEXES WITH 1,3-PROPANEDIAMINE-N,N,N’,N’-TETRAACETATE

by Nenad S Drašković, Dejan M Gurešić

The complexes Li2[Ni(1,3-pdta)]•5H2O and Li2[Cu(1,3-pdta)]•5H2O (where 1,3-pdta represents the 1,3-propanediaminetetraacetate anion) have been synthesized and characterized by applying IR and UV-vis spectroscopy. The obtained spectroscopic results of these complexes are discussed in relation to those for Mg[M(1,3-pdta)].8H2O complexes (M = Ni(II) and Cu(II)) of known crystal structure.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-13688 Published: 18 Jun 2017

Open Access

ON THE STARK BROADENING OF Ar VII SPECTRAL LINES

by Milan S. Dimitrijević, Sylvie Sahal-Bréchot

Stark broadening parameters, full width at half maximum of spectral line and shift, have been calculated for 3 spectral lines of Ar VII, for broadening by electron, proton, and He III impacts. For calculations, the semiclassical perturbation approach in the impact approximation has been used. The results are provided for temperatures from 20 000 K to 500 000 K and for an electron density of 1017 cm-3. Obtained results will be included in the STARK-B database which is also included in Virtual atomic and molecular data center (VAMDC).

picture_as_pdf View Full-Text DOI 10.5937/univtho7-13884

Open Access

CHARACTERISTICS OF HYBRID BROADCAST BROADBAND TELEVISION (HBBTV)

by Branimir Jakšić, Ivana Milošević, Mile Petrović, Siniša Ilić, Slobodan Bojanić, Selena Vasić

This paper describes the working principle of hybrid broadcast-broadband TV (Hybrid Broadcast Broadband TV - HbbTV). The architecture of HbbTV system is given, the principle of its operation, as well as an overview of HbbTV specification standards that are in use, with their basic characteristics. Here are described the services provided by Hybrid TV. It is also provided an overview of the distribution of HbbTV services in Europe in terms of the number of TV channels that HbbTV services offer, the number of active hybrid TV devices, HbbTV standards which are in use and models of broadcast networks used to distribute HbbTV service.

picture_as_pdf View Full-Text DOI 10.5937/univtho7-14347