652 research outputs found
Kredibilitas Customer Service Dan Citra Perusahaan
: This study aims to analyse the relationship between credibility of customer service and corporate image by using explanatory with quantitative approach as the method. The total number of participants was 100. They are customers who have complaint or critique to the customer service about their service or other issues. It is found that there is a strong correlation between customer service and corporate image (r=0,743 or 74,3%). Sex, age, and education are the factors that determine this correlation
Energy Spectra and Normalized Power Spectral Densities of X-Ray Nova GS 2000+25
The X-ray energy spectra and Normalized Power Spectral Densities (NPSDs) of
an X-ray nova, GS 2000+25, were investigated. The X-ray energy spectra of the
source consist of two components: a hard component, which can be represented by
a power-law, and an ultra-soft component, represented by radiation from an
optically-thick accretion disk (the disk component). In a model in which the
power-law component is the Compton-scattered radiation, it is found that the
temperature of the incident blackbody radiation to the Compton cloud decrease
from 0.8 keV to 0.2 keV according to the decay of the intensity, which
coincides with that of the inner accretion disk. When the source changed from
the high-state to the low-state, both the photon index of the power-law
component (or Compton y-parameter) and the NPSD of the hard component
dramatically changed as did GS 1124-683. That is, the photon index changed from
2.2--2.6 to 1.7--1.8 and the absolute values of the NPSDs at 0.3 Hz of the hard
component in the low-state became about 10-times larger than those of the hard
component in the high-state. These X-ray properties were similar to those of
other black-hole candidates, such as Cyg X-1, GX 339-4, and LMC X-3.Comment: 24 pages, text only, Full version is published in PASJ 54, 609-627
(2002
Patient-Specific Neurovascular Simulator for Evaluating the Performance of Medical Robots and Instrumens
Proceedings of the 2006 IEEE International Conference on Robotics and Automation, Orlando, Florida, May 200
X-Ray Fluctuations from Locally Unstable Advection-Dominated Disks
The response of advection-dominated accretion disks to local disturbances is
examined by one-dimensional numerical simulations. It is generally believed
that advection-dominated disks are thermally stable. We, however, find that any
disurbance added onto accretion flow at large radii does not decay so rapidly
that it can move inward with roughly the free-fall velocity. Although
disturbances continue to be present, the global disk structure will not be
modified largely. This can account for persistent hard X-ray emission with
substantial variations observed in active galactic nuclei and stellar black
hole candidates during the hard state. Moreover, when the disturbance reaches
the innermost parts, an acoustic wave emerges, propagating outward as a shock
wave. The resultant light variation is roughly (time) symmetric and is quite
reminiscent of the observed X-ray shots of Cygnus X-1.Comment: plain TeX, 11 pages, without figures; to be published in ApJ Lette
Variability of Active Galactic Nuclei from the Optical to X-ray Regions
Some progress in understanding AGN variability is reviewed. Reprocessing of
X-ray radiation to produce significant amounts of longer-wavelength continua
seems to be ruled out. In some objects where there has been correlated X-ray
and optical variability, the amplitude of the optical variability has exceeded
the amplitude of X-ray variability. We suggest that accelerated particles
striking material could be linking X-ray and optical variability (as in
activity in the solar chromosphere). Beaming effects could be significant in
all types of AGN. The diversity in optical/X-ray relationships at different
times in the same object, and between different objects, might be explained by
changes in geometry and directions of motion relative to our line of sight.
Linear shot-noise models of the variability are ruled out; instead there must
be large-scale organization of variability. Variability occurs on
light-crossing timescales rather than viscous timescales and this probably
rules out the standard Shakura-Sunyaev accretion disk. Radio-loud and
radio-quiet AGNs have similar continuum shapes and similar variability
properties. This suggests similar continuum origins and variability mechanisms.
Despite their extreme X-ray variability, narrow-line Seyfert 1s (NLS1s) do not
show extreme optical variability.Comment: Invited talk given at Euro Asian Astronomical Society meeting in
Moscow, June 2002. 20 pages, 4 figures. References update
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