15,716 research outputs found
Wave-front sets in non-quasianalytic setting for Fourier Lebesgue and modulation spaces
We define and study wave-front sets for weighted Fourier-Lebesgue spaces when
the weights are moderate with respect to the associated functions for general
sequences which satisfy Komatsu's conditions . In
particular, when is the Gevrey sequence (, ) we
recover some previously observed results. Furthermore, we consider wave-front
sets for modulation spaces in the same setting, and prove the invariance
property related to the Fourier-Lebesgue type wave-front sets.Comment: 30 pages. arXiv admin note: text overlap with arXiv:1806.0440
Composition principles for generalized almost periodic functions
In this paper, we consider composition principles for generalized almost
periodic functions. We prove several new composition principles for the classes
of (asymptotically) Stepanov -almost periodic functions and (asymptotically,
equi-)Weyl -almost periodic functions, where and explain
how we can use some of them in the qualitative analysis of solutions for
certain classes of abstract semilinear Cauchy inclusions in Banach spaces
Development of a low profile laser Doppler probe for monitoring perfusion at the patient – mattress interface
The clinical importance of pressure ulcers is reviewed confirming the need for continuous monitoring of skin blood perfusion at the patient – mattress interface. The design of a low profile (H≈1mm) laser Doppler probe is then described together with the experimental setup used for evaluation. The results show that the performance of the new sensor does not vary significantly from that of currently available probes over a wide range of operating parameters. The authors conclude that the sensor design provides a low cost perfusion monitoring solution with potential to significantly reduce the risk of bed sores in hospital patients
Kolmogorov complexity spectrum for use in analysis of UV-B radiation time series
We have used the Kolmogorov complexity and sample entropy measures to
estimate the complexity of the UV-B radiation time series in the Vojvodina
region (Serbia) for the period 1990-2007. We defined the Kolmogorov complexity
spectrum and have introduced the Kolmogorov complexity spectrum highest value
(KLM). We have established the UV-B radiation time series on the basis of their
daily sum (dose) for seven representative places in this region using (i)
measured data, (ii) data calculated via a derived empirical formula and (iii)
data obtained by a parametric UV radiation model. We have calculated the
Kolmogorov complexity (KL) based on the Lempel-Ziv Algorithm (LZA), KLM and
Sample Entropy (SE) values for each time series. We have divided the period
1990-2007 into two sub-intervals: (a) 1990-1998 and (b)1999-2007 and calculated
the KL, KLM and SE values for the various time series in these sub-intervals.
It is found that during the period 1999-2007, there is a decrease in the KL,
KLM and SE, comparing to the period 1990-1998. This complexity loss may be
attributed to (i) the increased human intervention in the post civil war period
causing increase of the air pollution and (ii) the increased cloudiness due to
climate changes.Comment: 10 pages, 1 figure, 1 table. arXiv admin note: substantial text
overlap with arXiv:1301.2039; This paper has been accepted in Modern Physics
Letters B on Aug 14, 201
Analysis of Daily Streamflow Complexity by Kolmogorov Measures and Lyapunov Exponent
Analysis of daily streamflow variability in space and time is important for
water resources planning, development, and management. The natural variability
of streamflow is being complicated by anthropogenic influences and climate
change, which may introduce additional complexity into the phenomenological
records. To address this question for daily discharge data recorded during the
period 1989-2016 at twelve gauging stations on Brazos River in Texas (USA), we
use a set of novel quantitative tools: Kolmogorov complexity (KC) with its
derivative associated measures to assess complexity, and Lyapunov time (LT) to
assess predictability. We find that all daily discharge series exhibit long
memory with an increasing downflow tendency, while the randomness of the series
at individual sites cannot be definitively concluded. All Kolmogorov complexity
measures have relatively small values with the exception of the USGS (United
States Geological Survey) 08088610 station at Graford, Texas, which exhibits
the highest values of these complexity measures. This finding may be attributed
to the elevated effect of human activities at Graford, and proportionally
lesser effect at other stations. In addition, complexity tends to decrease
downflow, meaning that larger catchments are generally less influenced by
anthropogenic activity. The correction on randomness of Lyapunov time
(quantifying predictability) is found to be inversely proportional to the
Kolmogorov complexity, which strengthens our conclusion regarding the effect of
anthropogenic activities, considering that KC and LT are distinct measures,
based on rather different techniques
The creation of folk music program on Radio Belgrade before World War Two: Editorial policies and performing ensembles
This paper deals with the establishing of the organizing models, on one side,
and with folk music and its aesthetic characteristics in the interwar period,
on the other. This problem significantly contributed to the present meaning
of the term “folk music” (“narodna muzika”). The program of Radio Belgrade
(founded in 1929) contained a number of folk music shows, often with live
music. In order to develop folk music program, numerous vocal and
instrumental soloists were hired, and different bands accompanied them.
During that time, two official radio ensembles emerged - the Folk Radio
Orchestra and the Tambura Radio Orchestra - displacing from the program the
ensembles that were not concurrent to their technical and repertoire level.
The decisive power in designing the program concept and content, but also in
setting standards for the aesthetic values, was at the hands of music
editorship of Radio Belgrade. The radio category of folk music was especially
influenced by Petar Krstić (folk music editor in the period from 1930 to
1936) and his successor Mihajlo Vukdragović (1937-1940), who formally defined
all of the aforementioned characteristics, but in rather different ways. A
general ambivalence in the treatment of the ensembles that performed at the
radio reflects the implementation of their policies. In comparison to the
official orchestras, the tavern singers and players received poor reviews in
the editors’ reports, despite their strong presence on the program. On the
other side, the official orchestras were divided according to the regional
folklore instrumentarium, but also according to the quality of playing. The
Folk Radio Orchestra probably had double leadership, so it was possible to
observe different approaches to the music folklore, which eventually resulted
in a unique tendency towards cherishing folk music. This paper represents an
attempt to show how the media term “folk music” was constructed and where it
currently stands in comparison to the usual study objects of ethnomusicology
and popular music studies. My argument is that the discourse of authenticity
was fundamental for the creation of official folk music. [Projekat
Ministarstva nauke Republike Srbije, br. ON 177004: Serbian Musical
Identities within Local and Global Frameworks: Traditions, Changes,
Challenges
Sintering of different hydroxyapatite nanopowders
Poster presented at the Workshop: Processing of Nanostructured Ceramics, Polymers, and Composites, Faculty of Technology and Metallurgy, University of Belgrade, November 29–30, 201
Intergranular area microalloyed aluminium-silicate ceramics fractal analysis
Porous aluminium-silicate ceramics, modified by alloying with magnesium and microalloying with alluminium belongs to a group of advanced multifunctional ceramics materials. This multiphase solid-solid system has predominantly amorphous microstructure and micro morphology. Intergranular and interphase areas are very complex, because they represent areas, where numbered processes and interactions take place, making new boundaries and regions with fractal nature. Fractal analysis of intergranular microstructure has included determination of ceramic grain fractal dimension by using Richardson method. Considering the fractal nature of intergranular contacts, it is possible to establish correlation between material electrical properties and fractal analysis, as a tool for future correlation with microstructure characterization. [Projekat Ministarstva nauke Republike Srbije, br. ON 172057 i br. III 45012
Investigation of sintering kinetics of NiO using photo acoustic spectroscopy
Sintering kinetics of NiO was investigated using photo acoustic spectroscopy This method was used to follow the change of phase and amplitude of the photo acoustic signal of nickel-oxide samples sintered at 1373 K for 15-240 min. as a function of modulation frequency of the laser beam. Fitting of experimental data enabled determination of photo acoustic properties including thermal diffusivity of sintered nickel-oxide. Analysis of the change of sample density during sintering showed that the sintering process of this material can be observed from the view
Influence of dimensionality on phase transition in VO2 nanocrystals
Hydrothermally synthesized one-dimensional and two-dimensional nanocrystals of VO2 undergo phase transition around 65°C, where temperature and mechanism of phase transition are dependent on dimensionality of nanocrystals. Both nanocrystalline samples exhibit depression of phase transition temperature compared to the bulk material, the magnitude of which depends on the dimensionality of the nanocrystal. One-dimensional nanoribbons exhibit lower phase transition temperature and higher values of apparent activation energy than two-dimensional nanosheets. The phase transition exhibits as a complex process with somewhat lower value of enthalpy than the phase transition in the bulk, probably due to higher proportion of surface atoms in the nanocrystals. High values of apparent activation energy indicate that individual steps of the phase transition involve simultaneous movement of large groups of atoms, as expected for single-domain nanocrystalline materials. [Projekat Ministarstva nauke Republike Srbije, br. 142015
- …