324 research outputs found
Two-dimensional Kolmogorov-type Goodness-of-fit Tests Based on Characterizations and their Asymptotic Efficiencies
In this paper new two-dimensional goodness of fit tests are proposed. They
are of supremum-type and are based on different types of characterizations. For
the first time a characterization based on independence of two statistics is
used for goodness-of-fit testing. The asymptotics of the statistics is studied
and Bahadur efficiencies of the tests against some close alternatives are
calculated. In the process a theorem on large deviations of Kolmogorov-type
statistics has been extended to the multidimensional case
Some Characterizations of Exponential Distribution Based on Order Statistics
In this paper some new characterizing theorems of exponential distribution
based on order statistics are presented. Some existing results are generalized
and the open conjecture by Arnold and Villasenor is solved
Constrained Dynamics of Tachyon Field in FRWL Spacetime
In this paper we continue study of tachyon scalar field described by a
Dirac-Born-Infeld (DBI) type action with constraints in the cosmological
context. The proposed extension of the system introducing an auxiliary field in
the minisuperspace framework is discussed. A new equivalent set of constraints
is constructed, satisfying the usual regularity conditions.Comment: 10 pages, to be published in the Special Issue of the Facta
Universitatis Series: Physics, Chemistry and Technology devoted to the
SEENET-MTP Balkan Workshop BSW2019 (3-14 June 2018, Nis, Serbia
Serbian civilian capacities for peace operations: Untapped potential
This article examines Serbia's capacities to participate in civilian peace operations, including the analysis of legislation regulating international cooperation and contribution to peace operations. Furthermore, based on interviews with representatives of various institutions, it also addresses the key practical challenges that these institutions are currently facing in civilian contribution. It examines the roles of relevant stakeholders, the Ministry of Foreign Affairs, the military and the police, with potential participants from other branches of government also included in this analysis. The research sample also included local persons working by contract for international organizations in Serbia, in order to examine the capacities they possess. Several challenges and opportunities for further development of existing frameworks were detected therein. Initial interest expressed by various 'civil' ministries to contribute to peace operations (Ministry of Foreign Trade, Ministry of Justice) could contribute to building of CIVCAP. Also, existing institutions, such as Office for cooperation with CSOs and Governmental Department of Human Resources Management could be easily turned into rosters of potential candidates for peace operations. The article argues that a huge potential exists in Serbia, however, its adequate use is prevented by the lack of clear foreign policy goals and coherent government policy. In this regard, the article recommends the government to increase the existing training capacities, coordinate the efforts of various stakeholders and establish two potential rosters of experts
Geospatial determinants of mega-landslides in Serbia
Полазиште у овој дисертацији било је да се дефинише појаммегаклизишта. На основу прегледа највећих клизишта на Земљи као референтанкритеријум за класификацију клизишта према величини узета је запреминаклизишта. Уважавајући запреминску класификацију клизишта ICL-a и номенклатурумеђународног система јединица (SI) као основни квантитативни критеријум заиздвајање мегаклизишта узета је запремина од 106m3. Основни извор података заистраживање представљали су дигитални модели терена (ДМТ) који су самосталнокреирани на основу картографске основе високе резолуције. У следећој фазиприступило се инвентаризацији мегаклизишта. Границе појединих мегаклизиштапреузете су из ранијих истраживања. Границе осталих клизишта самостално суреконструисане на основу анализе ДМТ, топографских карата и теренскихистраживања. На овај начин, задовољавајући квантитативни критеријум (запремина>106m3), издвојено је 25 мегаклизишта на територији Србије. На основу просторнедистрибуције извршена је њихова регионализација на Подунавска, Поморавска иПосавинска клизишта. У наредном кораку спроведена је њихова геоморфометријскаанализа. Као основни елементи ове анализе били су контурна и топографскаморфометрија. Најзначајнији природни услови за формирање мегаклизиштапрепознати су у геолошкој подлози (кластични седименти), неотектоници игеоморфологији (умерена и велика вертикална рашчлањеност рељефа, долинскаасиметрија). Најчешћи узрочник клизишта је речна ерозија (поткопавање ножицеклизишта) док су у улози активатора издвајају падавине (Јовачко тециште, Умка,Дубоко, Крчедин). Приликом класификације клизишта према механизму кретања иактивности дефинисани су квалитативни и квантитативни индикатори на основу којихсу одређени типови клизишта. Утврђено је да се мегаклизишта у географскојсредини не понашају инертно већ постоји одређена интеракција која је условљенастањем активности клизишта као и свешћу човека (лаика и стручњака). У зависностида ли их човек доживљава као природан услов или као хазард разликују се она којасу се интегрисала од оних која се нису интегрисала у географску средину. У случајуда се нису интегрисала у простору доћи ће до појаве трансформације итранспозиције географских објеката и процеса.The starting point of this dissertation was a search for the definition of megalandslides.Analysing the data related to the largest landslides on the Earth, the landslidevolume was chosen to be the indicator of size. Taking into account the ICL volumeclassification and SI nomenclature, the main quantitative criterion is the volume of 106m3.The main data sources were the Digital Terrain Models (DTMs); the high resolution modelscreated particularly for this purpose on the basis of official topographical maps. The nextstep was inventorization. For some of the selected mega-landslides, the boundaries weretaken from the available sources. For all the other landslides, the boundaries have beencreated within the present research, using the DTM analysis, topographical maps and fieldresearch/mapping. In this way, the total of 25 mega-landslides in Serbia were selected,fulfilling the volume criterion. Their spatial distribution enabled the regionalization based onthe river systems, to Danube- , Morava- and Sava- related landslides. The next step of theresearch was the geomorphometric analysis, the main elements of which are the outlineand topographic morphometry. The most significant natural conditions for mega-landslidedevelopment are geological composition (clastic sediments), tectonics andgeomorphological characteristics (moderate or large vertical dissection, valley asymmetry).The most usual cause of sliding is a river erosion (landslide toe undercutting), while heavyprecipitation is the most usual reason of landslide activation (e.g. Jovac earthflow, Umka,Duboko, Krčedin landslides). Landslide classification according to the movementmechanism and activity defines the qualitative and quantitative indicators for the definitionof their typology. Within the geographical environment, the landslides are not inert – thereis a particular interaction conditioned by landslide activity degree, as well as by humanperception (both expert and laymen). Depending on human perception of particularlandslides (either as natural features or as hazards), it is possible to distinguish betweenthose which are integrated into geographical milieu and those which are not. In case theyare not integrated, the transformation and transposition of geographical objects andprocesses will occur
Razvoj i primena ARCH i GARCH modela u funkciji optimizacije strategije investiranja na finansijskim tržištima zemalja u razvoju
Predmet istraživanja doktorske disertacije se odnosi na analizu, razvoj i primenu značajnih finansijskih ekonometrijskih modela ARCH (engl. Autoregressive Conditionally Heteroscedastic) i GARCH (engl. Generalized Autoregressive Conditionally Heteroscedastic) na finansijskim tržištima zemalja u razvoju. Razvoj modela podrazumeva uključivanje u modele faktore za koje se de facto pretpostavlja da utiču na kretanja na finansijskim tržištima, a tu se ubrajaju: stopa inflacije, referentna kamatna stopa, kamatna stopa na državne obveznice, bruto domaći proizvod i strane direktne investicije.U posmatranom periodu u disertaciji od 2005. do 2015.te, primena prilagođenih modela ARCH i GARCH doprinosi optimizaciji strategije investiranja na finansijskim tržištima zemalja u razvoju: Slovenije, Mađarske, Hrvatske i Srbije. Istraživanje se primenilo u segmentiranom periodu posmatranja koje u disertaciji obuhvata period od 2005. do 2015. godine i podeljen je na tri segmenta: predkrizni (2005–2007), krizni (2008–2010) i postkrizni (2011–2015) period. Osnovni cilj istrаživаnjа, odnosno disertacije, jeste ispitivаnje znаčаjnosti primene prilagođenih ARCH i GARCH modela i njihovih rezultata na finansijskim tržištima zemalja u razvoju u segmentiranom periodu posmatranja (predkriznom, kriznom i postkriznom) u funkciji optimizacije strategije investiranja. Razvoj i primena prilagođenih regresionih ekonometrijskih modela ARCH i GARCH ima za cilj da prikaže tačnu korelacionu vezu između dnevnih stopa povrata berzanskih indeksa i faktora koji utiču na kretanje berzanskih indeksa (stopa inflacije, referentna kamatna stopa, kamatna stopa na državne obveznice, bruto domaći proizvod i strane direktne investicije). U skladu sa gore navedenim, disertacija ima za cilj da prikaže naučno verifikovana saznanja koja će doprineti donošenju optimalnih odluka o investiranju na finansijskim tržištima zemalja u razvoju
Indications for endoscopic sinus surgery at "Sisters of Charity" Uneversity Hospital from 2012 to 2017
Cilj ovog retrospektivnog randomiziranog istrživanja bio je utvrditi učestalost pojedinih indikacija za endoskopsku sinusnu kirurgiju na Klinici za otorinolaringologiju i kirurgiju glave i vrata Kliničkog bolničkog centra "Sestre milosrdnice" u razdoblju od 1. siječnja 2012. do 31. prosinca 2016. Prikazane su i vrste operativnih zahvata te učestalost istih, učestalost pridruženih stanja, dviju vrsta anestezije i hitnih stanja. Također su pokazane povezanosti među svim opisanim parametrima. Istraživanje je provedeno na 350 pacijenata, od toga 165 žena i 185 muškaraca, čiji je raspon dobi bio od 6 do 81 godine, s medijanom dobi od 43,5 godina. Najčešća dijagnoza koju navodimo kao indikacije za operativni zahvat u promatranoj populaciji bila je kronični sinuitis bez nosne polipoze, slijedi je kronični sinuitis s nosnom polipozom te sinusne ciste s mnogo manjom učestalosti. Većina pacijenata liječena je kombinacijom etmoidektomije, antrostomije maksilarnog sinusa i polipektomije, pri čemu se etmoidektomija može izdvojiti kao najčešći zahvat endoskopske sinusne kirurgije. Pridružena stanja su bila brojna, ali je u najvećem broju slučajeva bila zastupljena deformacija nosnog septuma. Endotrahealna anestezija bila je zastupljenija od lokalne, a hitni zahvati su bili potrebni kod 5 pacijenata.The goal of this retrospective radomized study was to assess the incidence of indications for endoscopic sinus surgery at the Department of Otorhinolaryngology and Head and Neck Surgery at the Sisters of Charity University Hospital between
January 1, 2012 and December 31, 2016. The study also included types of operations and their incidence, the incidence of conditions adjacent to these indications, as well as the types of anesthesia and emergencies. The associations between all the mentioned parameters were also explained. The study was done on 350 patients, of whom 165 were women and 185 men, from 6 to 81 years of age, with the median age being 43.5 years. The most frequent diagnosis that was listed as an
indication for operation in the observed population was chronic sinusitis without nasal polyposis, followed by chronic sinusitis with nasal polyposis and sinus cysts, at a significantly lower rate. Most of the patients we observed were treated with a combination of ethmoidectomy, maxillary sinus antrostomy and polypectomy, with ethmoidecomy being the most frequent procedure of endoscopic sinus surgery. Adjacent diagnoses were abundant, but in most cases the associated diagnosis was nasal septum deformity. Endotracheal anesthesia was used more often than local, and emergency procedures were performed on 5 patients
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