Milos Davidovic

• M. Sc. EE, PhD
• University of Belgrade

Convergence of finite-element-method solutions for electric field distributions of resonant modes is discussed and analyzed in two canonical microwave cavity problems when B-splines are utilized for geometrical modeling of elements. While the analyzed problems, namely, those of a spherical cavity and a ridged cavity, respectively, are relatively...

Time-frequency analysis is important to identify the localized information of a non-stationary signal in the time and frequency domains simultaneously. There are few different time-frequency analysis methods available with their own specialty and suitability. In quantum mechanics Husimi function of any quantum mechanical state arises naturally when...

Кontinuirano praćenje nivoa zagađujućih materija u vazduhu kao što su suspendovane čestice od izuzetne je važnosti kako bi se mogle preduzeti odgovarajuće mere zaštite životne sredine i zdravlja ljudi. Unapređenje sistema nadzora ovih zagađujućih materija, uz korišćenje novih tehnologija kao što su senzorske mreže i kompaktni senzori, može biti od...

Conventional air quality monitoring networks typically tend to be sparse over areas of interest. Because of the high cost of establishing such monitoring systems, some areas are often completely left out of regulatory monitoring networks. Recently, a new paradigm in monitoring has emerged that utilizes low-cost air pollution sensors, thus making it...

In this study, we describe the development of seasonal winter and summer (heating and non-heating season) land use regression (LUR) models for PM2.5 mass concentration for the city of Novi Sad, Serbia. The PM2.5 data were obtained through an extensive seasonal measurement campaign conducted at 21 locations in urban, urban/industrial, industrial and...

The aim of the study was to analyse relationship between PM2.5 and PM10 concentrations, traffic density and meteorological factors during the week with regular traffic regime and first week of COVID-19 lockdown in Novi Sad, Serbia. During the study period, which included working days and weekends, traffic emission contributions to PMs were also det...

Scalable and effective calibration is a fundamental requirement for Low Cost Air Quality Monitoring Systems and will enable accurate and pervasive monitoring in cities. Suffering from environmental interferences and fabrication variance, these devices need to encompass sensors specific and complex calibration processes for reaching a sufficient acc...

Particulate matter (PM) in air has been proven to be hazardous to human health. Here we focused on analysis of PM data we obtained from the same campaign which was presented in our previous study. Multivariate linear and random forest models were used for the calibration and analysis. In our linear regression model the inputs were PMs, temperature...

A novel statistical model based on a two-layer, contact and information, graph is suggested in order to study the influence of disease prevalence on voluntary general population vaccination during the COVID-19 outbreak. Details about the structure and number of susceptible, infectious, and recovered/vaccinated individuals from the contact layer are...

Changes in air pollution in the region of the city of Novi Sad due to the COVID-19 induced state of emergency were evaluated while using data from permanently operating air quality monitoring stations belonging to the national, regional, and local networks, as well as ad hoc deployed low-cost particulate matter (PM) sensors. The low-cost sensors we...

Featured Application An ANN model successfully helped in harmonizing inputs from several instruments of different grade (low cost radon and lab grade particulate matter monitors) and enabled predictions of small ions concentration of comparable quality to the lab grade Gerdien type instrument. Abstract In this work we explore the relationship betw...

Air quality information from high-end instruments is currently supplemented, and even challenged, by data and information based on low-cost sensor systems. Low-cost sensor systems, including particulate matter sensors/monitors (LCS-PM), can be deployed in larger numbers because of their lower costs, but questions remain regarding the quality of dat...

We consider a linear quantum amplifier consisting of NA two-level atoms and study the problem of amplification of N-photon states. The N-photon states are associated with N-quantum states of the harmonic oscillator. We show that the process of interaction of the electromagnetic field with atoms can be associated with some transformation of the phas...

The current compliance networks of automatic air-quality monitoring stations in large urban environments are not sufficient to provide spatial and temporal measurement resolution for realistic assessment of personal exposure to pollutants. Small low-cost sensor platforms with greater mobility and expected lower maintenance costs, are increasingly b...

In a diffraction pattern of a laser beam on a sharp edge of a half-plane two characteristic regions are noticeable. In the central region, one can notice the diffraction of laser light in the region of geometric shadow, while intensity oscillations are observed in the non-obstructed area. There are also, on both sides of the edge, very long light t...

In the diffraction pattern produced by a half-plane sharp edge when it obstructs the passage of a laser beam, two characteristic regions are noticeable. There is a central region, where it can be noticed the diffraction of laser light in the region of geometric shadow, while intensity oscillations are observed in the non-obstructed area. On both si...

Рассматриваются преобразования масштаба $(q,p)\to(\lambda q,\lambda p)$ в фазовом пространстве. Они индуцируют преобразования функций Хусими $H(q,p)$, заданных на этом пространстве. Рассматриваются функции Хусими состояний, которые являются произвольной суперпозицией $n$-частичных состояний гармонического осциллятора. Развит метод, позволяющий нахо...

We consider scale transformations (q, p) → (λq, λp) in phase space. They induce transformations of the Husimi functions H(q, p) defined in this space. We consider the Husimi functions for states that are arbitrary superpositions of n-particle states of a harmonic oscillator. We develop a method that allows finding so-called stretched states to whic...

The aim of this research was to investigate the usability of low-cost Sharp GP2Y1010AU0F sensors attached to Arduino platforms for indoor measurement of PM 2.5 mass concentrations. The OSIRIS (Turnkey Instruments, Model 2315) particulate monitor has been used for colocation. Strong positive correlation (r>0.7) was observed between the mean 15-min P...

Children spend substantial part of their childhood in school buildings. The school staff might not have the time or knowledge to investigate the indoor environment, even though they acknowledge it could be improved, nor do they have the capacity to have a dialogue with the students regarding good indoor environment. As part of CITI-SENSE project, w...

We consider the Husimi Q(q, p)-functions which are quantum quasiprobability distributions on the phase space. It is known that, under a scaling transform (q; p) → (⋋q; ⋋p), the Husimi function of any physical state is converted into a function which is also the Husimi function of some physical state. More precisely, it has been proved that, if Q(q,...

We propose a new method for the derivation of Husimi symbols, for operators that are given in the form of products of an arbitrary number of coordinates, and momentum operators, in an arbitrary order. For such an operator, in the standard approach, one expresses coordinate and momentum operators as a linear combination of the creation and annihilat...

We present a derivation of the Lagrangian for a system of relativistic particles, starting from d'Alembert's principle. We follow the virtually forgotten derivation of Pars, using generally accepted notation, while introducing some new steps in the derivation and clarifying others.

We propose a new method for calculating Husimi symbols of operators. In contrast to the standard method, it does not require using the anti-normal-ordering procedure. According to this method, the coordinate and momentum operators \(\hat q\) and \(\hat p\) are assigned other operators \(\hat X\) and \(\hat P\) satisfying the same commutation relati...

We analyze the widely spread statement that moving clocks go more slowly than those at rest. For purposes of clarifying this statement, we explicitly introduce the periods of clocks, which are absent in the Lorentz transformations. Due to this, the statement under consideration, based exclusively on the direct application of Lorentz transformations...

Novel type of finite elements, based on independent three-dimensional higher-order modeling of geometry and electric fields using trivariate B-spline functions, is presented. The method is evaluated in simulations of rectangular, spherical, and ridged canonical microwave cavity problems. The examples demonstrate excellent accuracy and efficiency of...

In this paper, a detailed comparison of modal electromagnetic field distribution in two canonical microwave cavities, obtained via analytical and recently introduced numerical approaches, is presented and discussed. While the analyzed problems, namely, those of a spherical cavity and a ridged cavity are relatively simple, they still provide valuabl...

A method for obtaining an optimal concrete container composition used for storing radioactive waste from nuclear power plants is developed. It is applied to the radionuclides 60Co, 137Cs, 85Sr, and 54Mn. A set of recipes for concrete composition leading to an optimal solution is given.

A method for obtaining an optimal concrete container composition used for storing radioactive waste from nuclear power plants is developed. It is applied to the radionuclides Co-60, Cs-137, Sr-85, and Mn-54. A set of recipes for concrete composition leading to an optimal solution is given.

In the treatment of 133Ba decay by the method of coincidence summing, the transitions to the first two excited states of 133Cs were ignored in former works. By applying the most accurate values for these transitions available in literature, we include them into the count rate equations and obtain solutions for the corresponding system. As a result...

A novel entire-domain finite element technique based on curvilinear hexahedral geometrical modeling using B-splines in conjunction with higher order hierarchical polynomial curl-conforming vector basis functions for field expansions is proposed for electromagnetic analysis of microwave devices. The effectiveness of the technique is evaluated in ana...

A new method for deriving counting rate equations describing coincidence summing of gamma and X-rays for germanium spectrometers is developed. It is applied to the decay of 139Ce and 57Co. It is shown that the results obtained using the proposed method are in complete agreement with the results obtained using other methods, however these results ar...

To better elucidate the essential energy transmission mechanism in the most common, typical waveguides, the electromagnetic energy flow lines for a planar optical slab waveguide and a microwave rectangular waveguide are constructed. The obtained results supply more direct and transparent insight into the distribution of electromagnetic energy in th...

Radiation sensing MOSFETs (RADFETs) have found numerous applications in space research, as well as in nuclear technology and research, and radiotherapy. Since proton irradiation is an essential part of the space radiation environment, it is important to know RADFET proton response precisely. In this work a numerical simulation of RADFET proton resp...