932 research outputs found
Exploring the cosmic microwave background as a composition of signals with Kolmogorov analysis
The problem of separation of different signals in the Cosmic Microwave
Background (CMB) radiation using the difference in their statistics is
analyzed. Considering samples of sequences which model the CMB as a
superposition of signals, we show how the Kolmogorov stochasticity parameter
acts as a relevant descriptor, either qualitatively or quantitatively, to
distinguish the statistical properties of the cosmological and secondary
signals.Comment: Mod. Phys. Lett. (in press), 13 pages, 7 figure
Probing the statistic in the cosmic microwave background
Kolmogorov's statistic is used for the analysis of properties of
perturbations in the Cosmic Microwave Background signal. We obtain the maps of
the Kolmogorov stochasticity parameter for W and V band temperature data of
WMAP which are differently affected by the Galactic disk radiation and then we
model datasets with various statistic of perturbations. The analysis shows that
the Kolmogorov's parameter can be an efficient tool for the separation of
Cosmic Microwave Background from the contaminating radiations due to their
different statistical properties.Comment: 6 pages, 4 figure
Analytical models of probability distribution and excess noise factor of Solid State Photomultiplier signals with crosstalk
Silicon Photomultipliers (SiPM), also so-called Solid State Photomultipliers
(SSPM), are based on Geiger mode avalanche breakdown limited by strong negative
feedback. SSPM can detect and resolve single photons due to high gain and
ultra-low excess noise of avalanche multiplication in this mode. Crosstalk and
afterpulsing processes associated with the high gain introduce specific excess
noise and deteriorate photon number resolution of the SSPM. Probabilistic
features of these processes are widely studied because of its high importance
for the SSPM design, characterization, optimization and application, but the
process modeling is mostly based on Monte Carlo simulations and numerical
methods. In this study, crosstalk is considered to be a branching Poisson
process, and analytical models of probability distribution and excess noise
factor (ENF) of SSPM signals based on the Borel distribution as an advance on
the geometric distribution models are presented and discussed. The models are
found to be in a good agreement with the experimental probability distributions
for dark counts and a few photon spectrums in a wide range of fired pixels
number as well as with observed super-linear behavior of crosstalk ENF.Comment: 10 pages, 2 tables, 3 figures, Reported at 6th International
Conference on "New Developments In Photodetection - NDIP11
On the Earth's tidal perturbations for the LARES satellite
Frame dragging, one of the outstanding phenomena predicted by General
Relativity, is efficiently studied by means of the laser-ranged satellites
LARES, LAGEOS and LAGEOS 2. The accurate analysis of the orbital perturbations
of Earth's solid and ocean tides has been relevant for increasing the accuracy
in the test of frame-dragging using these three satellites. The Earth's tidal
perturbations acting on the LARES satellite are obtained for the 110
significant modes of corresponding Doodson number and are exhibited to enable
the comparison to those of the LAGEOS and LAGEOS-2 satellites. For LARES we
represent 29 perturbation modes for l=2,3,4 for ocean tides.Comment: 14 pages, 9 figures, to appear in Eur Phys J Plus (subm. Sept 20,
2017
Hubble Diagram of Gamma-Rays Bursts calibrated with Gurzadyan-Xue Cosmology
Gamma-ray bursts (GRBs) being the most luminous among known cosmic objects
carry an essential potential for cosmological studies if properly used as
standard candles. In this paper we test with GRBs the cosmological predictions
of the Gurzadyan-Xue (GX) model of dark energy, a novel theory that predicts,
without any free parameters, the current vacuum fluctuation energy density
close to the value inferred from the SNIa observations. We also compare the GX
results with those predicted by the concordance scenario -CDM.
According to the statistical approach by Schaefer (2007), the use of several
empirical relations obtained from GRBs observables, after a consistent
calibration for a specific model, enables one to probe current cosmological
models. Based on this recently introduced method, we use the 69 GRBs sample
collected by Schaefer (2007); and the most recently released SWIFT satellite
data (Sakamoto et al. 2007) together with the 41 GRBs sample collected by
Rizzuto et al. (2007), which has the more firmly determined redshifts. Both
data samples span a distance scale up to redshift about 7. We show that the GX
models are compatible with the Hubble diagram of the Schaefer (2007) 69 GRBs
sample. Such adjustment is almost identical to the one for the concordance
-CDM.Comment: 9 pages, 17 figures, 11 tables; Astr. & Astrophys. (in press
A weakly random Universe?
The cosmic microwave background (CMB) radiation is characterized by
well-established scales, the 2.7 K temperature of the Planckian spectrum and
the amplitude of the temperature anisotropy. These features were
instrumental in indicating the hot and equilibrium phases of the early history
of the Universe and its large scale isotropy, respectively. We now reveal one
more intrinsic scale in CMB properties. We introduce a method developed
originally by Kolmogorov, that quantifies a degree of randomness (chaos) in a
set of numbers, such as measurements of the CMB temperature in some region.
Considering CMB as a composition of random and regular signals, we solve the
inverse problem of recovering of their mutual fractions from the temperature
sky maps. Deriving the empirical Kolmogorov's function in the Wilkinson
Microwave Anisotropy Probe's maps, we obtain the fraction of the random signal
to be about 20 per cent, i.e. the cosmological sky is a weakly random one. The
paper is dedicated to the memory of Vladimir Arnold (1937-2010).Comment: 4 pages, 3 figs, A & A (Lett) in press; to match the published
versio
The Role and Necessity of Change Management in Organizations։ Investing CRM as an Effective System to Manage Customer Relations
This paper summarizes the arguments and counterarguments within the scientific discussion on the issue of change management characteristics in organizations. The main purpose of the research is to find out and discuss the role of change management in organizations, the main change management models, the benefits of investing CRM in a banking system that will change the way of work. A systematization of literary sources on the issue of change management presents some models steps of change management in organization. It indicates the importance of change management in today’s fast-moving world. Investigation of the topic proves that change management may help organizations become more effective customer-oriented. Analysis in the paper is carried out in the following logical sequence: literature review shows some examples of international experience of the discussed topic; also, the experience of CRM investing is discussed in one of the Armenian banks. Methodological tools of the research methods were analysis and synthesis, surveys. The paper presents the results of an empirical study, which shows that there are some transactions for which people prefer going to the bank. Certain services tend to go online, for example, to request account information or transfer money between accounts. The trend is that customers are moving more and more to online platforms. It was due to the introduction of the latest IT technologies in the banking system; also, during Covid-19, people preferred to do transactions online. The results show that it is necessary to use CRM tools to manage customer relationships throughout a customer life cycle, including marketing, sales, digital marketing, and customer service interactions. We suggest using CRM tools in banks to identify customers' needs as much as possible to build a stable and long-lasting bank-customer relationship. The results of the research can be helpful for banks to improve their experience, invest in CRM systems and do better change management
Planck's confirmation of the M31 disk and halo rotation
Planck's data acquired during the first 15.4 months of observations towards
both the disk and halo of the M31 galaxy are analyzed. We confirm the existence
of a temperature asymmetry, previously detected by using the 7-year WMAP data,
along the direction of the M31 rotation, therefore indicative of a
Doppler-induced effect. The asymmetry extends up to about 10 degrees (about 130
kpc) from the M31 center. We also investigate the recent issue raised in Rubin
and Loeb (2014) about the kinetic Sunyaev-Zeldovich effect from the diffuse hot
gas in the Local Group, predicted to generate a hot spot of a few degrees size
in the CMB maps in the direction of M31, where the free electron optical depth
gets the maximum value. We also consider the issue whether in the opposite
direction with respect to the M31 galaxy the same effect induces a minimum in
temperature in the Planck's maps of the sky. We find that the Planck's data at
100 GHz show an effect even larger than that expected.Comment: 4 pages, 1 table, 2 figures, in press as a Letter in A&
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