BER Performance of IM/DD FSO System with OOK using APD Receiver

In this paper, the performance of intensity-modulated with direct detection (IM/DD) free space optical (FSO) system using the on-off keying (OOK) and avalanche photodiode (APD) receiver is observed. The gamma-gamma model is used to describe the effect of atmospheric turbulence since it provides good agreement in the wide range of atmospheric conditions. In addition, the same FSO system with equal gain combining applied at the reception is analyzed. After theoretical derivation of the expression for the bit error rate (BER), the numerical integration with previously specified relative calculation error is performed. Numerical results are presented and confirmed by Monte Carlo simulations. The effects of the FSO link and receiver parameters on the BER performance are discussed. The results illustrate that the optimal APD gain in the minimum BER sense depends considerably on the link distance, atmospheric turbulence strength and receiver temperature. In addition, the value of this optimal gain is slightly different in the case of spatial diversity application compared with single channel reception

Impact of climatic factors to the percentage of young in the population of brown hare (Lepus europaeus P) in the Bačka district

Climatic factors, especially temperature and precipitations, greatly affect the dynamics of the hare number and population. Climatic factors directly affect the physiological and reproductive processes of both individuals and entire populations, or indirectly, through the availability of food, competition with other species, predators and other. The age structure of the hare population at the end of the period of reproduction is an important indicator of the population growth that is used for planning the level of explotation of the hare population (hunting). The rational use of the hare's population is one of the most important protection procedures and it should be well monitored and controlled by the hunting professionals. We used the average monthly temperature and the sum of monthly precipitations in the hare reproductive period (March-September) during ten years (2000 - 2009), together with the percent of young in the hare population, on the territory of Bačka, for multiple regression (stepwise) analysis. Results of the regression analysis show an association between the percentage of young hares and the influence of climatic factors. The average temperature and sum of precipitation in June, are the strongest predictor of the percent of young in the hare’s population in Bačka. According to the coefficient of determination (R2=0.50) climatic parameters account for 50% of variance in the percentage of young hares in Bačka. The regression correlation coefficient of all factors was R=0.70, which is on the border line between medium and high correlation

Another Way for the Laboratory Preparation ofAnhydrous Chromium(III) Chloride

Two methods for the laboratory preparation of anhydrous chromium(III) chloride are described in the standard handbooks of inorganic syntheses, i. e. (i) the chromium metal is heated in a porcelain tube in a stream of chlorine at high temperature, (ii) the green aqua-chloride [CrCl2 (H2 0)4 ]Cl · 2H20 is heated and the resulting mass of oxide and basic chloride is then chlorinated with carbon tetrachloride

An exact analytical solution for the second order slip-corrected Reynolds lubrication equation

Izvedena je opšta Rejnoldsova jednačina podmazivanja za uslove strujanja sa klizanjem primenom opštih graničnih uslova klizanja drugog reda i pokazano je da ona ima tačno analitičko rešenje. Rešenje je dobijeno tansformacijom zavisno promenljive što je dovelo do mogućnosti analitičkog proračuna raspodele pritiska i masenog protoka u mikroležaju. Na taj način, poređenjem sa datim analitičkim rešenjem omogućena je provera eksperimentalnih i numeričkih rezultata za strujanje gasa u mikroležajima.We derive a general slip-corrected compressible Reynolds lubrication equation, valid for any choice of the slip velocities, and show that it possesses the exact analytical solution. It is obtained by a suitable transformation of the dependent variable, and it yields both the pressure distribution in the bearing and the mass flow rate through it. It can be usefully applied for testing the other, experimental or numerical results obtained under the same or similar physical conditions, against this solution

An exact analytical solution for the second order slip-corrected Reynolds lubrication equation

Izvedena je opšta Rejnoldsova jednačina podmazivanja za uslove strujanja sa klizanjem primenom opštih graničnih uslova klizanja drugog reda i pokazano je da ona ima tačno analitičko rešenje. Rešenje je dobijeno tansformacijom zavisno promenljive što je dovelo do mogućnosti analitičkog proračuna raspodele pritiska i masenog protoka u mikroležaju. Na taj način, poređenjem sa datim analitičkim rešenjem omogućena je provera eksperimentalnih i numeričkih rezultata za strujanje gasa u mikroležajima.We derive a general slip-corrected compressible Reynolds lubrication equation, valid for any choice of the slip velocities, and show that it possesses the exact analytical solution. It is obtained by a suitable transformation of the dependent variable, and it yields both the pressure distribution in the bearing and the mass flow rate through it. It can be usefully applied for testing the other, experimental or numerical results obtained under the same or similar physical conditions, against this solution

The exact analytical solution for the gas lubricated bearing in the slip and continuum flow regime

The exact analytical solution for the compressible two-dimensional gas flow in the microbearing is presented. The general slip-corrected Reynolds lubrication equation is derived and it is shown that it possesses an exact analytical solution. It is obtained by a suitable transformation of the independent variable, and it provides the pressure distribution in the bearing as well as the mass flow rate through it. By neglecting the rarefaction effect, this solution is also applicable to the continuum gas flow in the bearing, which also does not exist in the open literature. The obtained analytical solution can be usefully applied for testing the other, experimental or numerical results

Problemi normativne snage i kritike agonističke participacije - ka mogućoj komplementarnosti agonističke i participativne demokratije

In this article I argue that there are grounds for considering agonistic democracy and participatory democracy complementarity in order to institutionalize agonism which has thus far lacked an elaborate articulation of its institutional dimension. The two democratic theories share a commitment toward widening the scope of the political as a way of inclusion of citizens and their subsequent political subjectivation and empowerment. Furthermore, there are authors on both sides who think democracy does not need foundations. Agonistic participation and contestation, on the one hand, and the broadening and strengthening of various sectors of political participation, on the other, both open up new possibilities for critique and change, but also create new risks. Building on a redefinition of agonisitic participation, I aim to attenuate an objection that agonism is normatively weak in terms of lacking resources to motivate citizens and justify their critique of practices of domination and oppression. The article concludes that we need to embrace agonistic participation as a means towards the development of democratic political judgement, as there are no other guarantees, i.e. secure foundations, for our ability to distinguish between democratic and non-democratic agon.U članku se tvrdi da postoje osnovi komplementarnosti agonističke demokratije i participativne demokratije u pogledu mogućnosti institucionalizacije agonizma koji dosad nije imao razrađenu institucionalnu dimenziju. Dve demokratske teorije dele težnju za širenjem političkog kao načina uključivanja građana i njihove političke subjektivizacije i osnaživanja. Takođe, ima autora na obe strane koji dele shvatanje da demokratiji nisu potrebni temelji. Agonističkom participacijom kao osporavanjem, s jedne strane, i širenjem i jačanjem različitih oblasti političke participacije, s druge, otvaraju se mogućnosti za kritiku i promenu, ali se prostor otvara i za rizike. Oslanjajući se na redefinisanu agonističku participaciju, želim da ublažim prigovor da agonizam nema normativnu snagu u smislu neposedovanja resursa za motivisanje građana i opravdanje njihove kritike praksi dominacije i ugnjetavanja. Zaključak je da je potrebno prihvatiti agonističku participaciju kao sredstvo razvijanja demokratskog političkog rasuđivanja jer nema drugih garancija, tj. nema sigurnosti temelja, koji bi nam omogućili da razlikujemo demokratski od nedemokratskog agona

Lišeni diskursa legitimacije - zazidane zemlje Centralne Evrope i politički subjektiviteti u nastajanju

In this paper I want to compare rare theoretical justifications of border walls with discourses on boundaries and walls by Central and Eastern European political actors in dealing with refugee crisis in 2015. I analyze three such discourses: consequentiality, discourse of responsibility for fair distribution of cosmopolitan duties, and nationalistic discourse. This comparison allows me to question applicability of Wendy Brown's argument that the states with waning sovereignty display symbols of force in building border walls aimed at defending fragile egos built around national and religious identities. Finally, I want to elucidate what type of political subjectivity is produced and legitimated by these acts of fortification within and around CEE 'walled' states.U ovom članku želim da uporedim retka teorijska tumačenja i opravdanja zidova na granicama sa diskursima o granicama i zidovima centralnoevropskih i istočnoevropskih političkih aktera koji se tiču izbegličke krize iz 2015. godine. Analiziram tri diskursa: konsekvencijalistički, diskurs odgovornosti za pravednu raspodelu kosmopolitskih dužnosti i nacionalistički diskurs. To poređenje treba da mi pomogne u preispitivanju primenjivosti argumenta Vendi Braun da države čiji su suvereniteti na izmaku pokazuju simbole moći i snage izgradnjom zidova koji treba da odbrane njihov krhki ego sagrađen oko nacionalnog ili religijskog identiteta. Najzad, želim da ocrtam političke subjektivitete koji bivaju proizvedeni i legitimisani činovima fortifikacije unutar i izvan zazidanih zemalja Centralne i Istočne Evrope