Multivariate classification and regression analysis of multiple meteorological variables and indoor radon activity concentration in Ground Level Laboratory in the Institute of Physics Belgrade, was ...performed and discussed. Meteorological variables used in this analysis were from radon active device, nearby meteorological station and finally from Global Data Assimilation System. Single variate analysis has identified variables with greatest value of Pearson's correlation coefficient with radon activity concentration and also, variables with greatest separation of events with increased radon activity concentration of over 200 Bqm-3 and of events with radon level below this value. This initial analysis is showing the expected behavior of radon concentration with meteorological variables, with emphasis on data periods with or without air conditioning and with emphasis on indoor water vapor pressure, which was, in our previous research, identified as important variable in analysis of radon variability. This single variate analysis, including all data, proved that Global Data Assimilation System data could be used as a good enough approximate replacement for meteorological data from nearby meteorological station for multivariate analysis. Variable importance of Boosted Decision Trees with Gradient boosting multivariate analysis method are shown for all three periods and most important variables were discussed. Multivariate regression analysis gave good results, and can be useful to better tune the multivariate analysis methods.
This paper reports a detailed study of crystal structure and dielectric properties of ruthenium-substituted calcium-copper titanates (CaCu
Ti
Ru
O
, CCTRO). A series of three samples with different ...stoichiometry was prepared: CaCu
Ti
Ru
O
,
= 0, 1 and 4, abbreviated as CCTO, CCT3RO and CCRO, respectively. A detailed structural analysis of CCTRO samples was done by the Rietveld refinement of XRPD data. The results show that, regardless of whether Ti
or Ru
ions are placed in
crystallographic position in
'
O
(CaCu
Ti
Ru
O
) unit cell, the crystal structure remains cubic with Im3¯ symmetry. Slight increases in the unit cell parameters, cell volume and interatomic distances indicate that Ru
ions with larger ionic radii (0.62 Å) than Ti
(0.605 Å) are incorporated in the CaCu
Ti
Ru
O
crystal lattice. The structural investigations were confirmed using TEM, HRTEM and ADF/STEM analyses, including EDXS elemental mapping. The effect of Ru atoms share in CaCu
Ti
Ru
O
samples on their electrical properties was determined by impedance and dielectric measurements. Results of dielectric measurements indicate that one atom of ruthenium per CaCu
Ti
Ru
O
unit cell transforms dielectric CCTO into conductive CCT3RO while preserving cubic crystal structure. Our findings about CCTO and CCT3RO ceramics promote them as ideal tandem to overcome the problem of stress on dielectric-electrode interfaces in capacitors.
The results of analysis using correlative and multivariate methods, as developed for data analysis in high-energy physics and implemented in the Toolkit for Multivariate Analysis software package, of ...the relations of the variation of increased radon concentration with climate variables in shallow underground laboratory is presented. Multivariate regression analysis identified a number of multivariate methods which can give a good evaluation of increased radon concentrations based on climate variables. The use of the multivariate regression methods will enable the investigation of the relations of specific climate variable with increased radon concentrations by analysis of regression methods resulting in 'mapped' underlying functional behaviour of radon concentrations depending on a wide spectrum of climate variables.
The Belgrade underground laboratory consists of two interconnected spaces, a
ground level laboratory and a shallow underground one, at 25 meters of water
equivalent. The laboratory hosts a ...low-background gamma spectroscopy system
and cosmic-ray muon detectors. With the recently adopted digital data
acquisition system it is possible to simultaneously study independent
operations of the two detector systems, as well as processes induced by
cosmic-ray muons in germanium spectrometers. Characteristics and potentials
of the present experimental setup, together with some preliminary results
for the flux of fast neutrons and stopped muons, are reported here.
Beogradska laboratorija sastoji se od dva laboratorijska prostora, jednog na
povrsini i jednog podzemnog, na dubini od 25 metara vodenog ekvivalenta.
Detaljno su opisani i ilustrovani potencijali ovih laboratorija za merenje
niskih aktivnosti i za kontinuirano merenje mionske i elektromagnetne
komponente kosmickog zracenja, kao i za studije procesa koje ova zracenja
indukuju u germanijumskim spektrometrima smestenim u niskofonskim podzemnim
laboratorijama. Sva ova merenja se izvode simultano, novim sistemom za
digitalnu spektroskopiju, a podaci se zapisuju dogadjaj po dogadjaj, i
analiziraju posle zavrsenih merenja. Takodje su prikazani preliminarni
rezultati koji su u fazi testiranja opreme dobijeni za fluks brzih neutrona i
zaustavljenih miona u povrsinskoj i u podzemnoj laboratoriji.
PR Projekat Ministarstva nauke Republike Srbije, br. 171002
In order to create valid CAD (computer-aided design) model for planning orthopedic operations, rapid prototyping, designing of implants, etc., the accurate definition of geometry and topology of all ...regions of human tibia is essential. Therefore it is logical to base process of geometrical modeling of human tibia on its anatomical and morphological properties. This paper presents and compares the application of two modeling techniques for creating geometrical model of the human tibia. The techniques applied are developed considering the natural features of the human tibia bone, and not only standard CAD techniques for geometrical modeling which are common in standard engineering. The application of these methods can be extended to other bones in human body.
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