238 research outputs found
A DESIGN METHOD OF LOGICAL SYSTEMS BASED ON PARALLEL PROCESSING
The paper outlines a design method of digital systems. The effect of problem partitioning
can be taken into consideration in the specification of the control proced ure. The event-
sequence represented by the operation order of the functional units can be handled and
so, maximally parallel structures can be formed in systematic steps. The functional units
are considered as "black boxes" and there is no need to make any difference between
hardware and software realisations during the design procedure of the architecture. For
that reason, the method can be used for redesigning e.g. a software problem, realised by a
single source, in order to implement it in a parallel structure, which may consist of either
software or hardware units
Constraining RRc candidates using SDSS colours
The light variations of first-overtone RR Lyrae stars and contact eclipsing
binaries can be difficult to distinguish. The Catalina Periodic Variable Star
catalog contains several misclassified objects, despite the classification
efforts by Drake et al. (2014). They used metallicity and surface gravity
derived from spectroscopic data (from the SDSS database) to rule out binaries.
Our aim is to further constrain the catalog using SDSS colours to estimate
physical parameters for stars that did not have spectroscopic data.Comment: 2 pages, 1 figure, proceedings of the RRL2015 - High-Precision
Studies of RR Lyrae Stars conference, to appear in the Communications from
the Konkoly Observator
Target selection of classical pulsating variables for space-based photometry
In a few years the Kepler and TESS missions will provide ultra-precise
photometry for thousands of RR Lyrae and hundreds of Cepheid stars. In the
extended Kepler mission all targets are proposed in the Guest Observer (GO)
Program, while the TESS space telescope will work with full frame images and a
~15-16th mag brightness limit with the possibility of short cadence
measurements for a limited number of pre-selected objects. This paper
highlights some details of the enormous and important work of the target
selection process made by the members of Working Group 7 (WG#7) of the Kepler
and TESS Asteroseismic Science Consortium.Comment: 4 pages, 1 figure, proceedings of the RRL2015 - High-Precision
Studies of RR Lyrae Stars conference, to appear in the Communications from
the Konkoly Observator
Total phenolic content and antioxidant capacity of ginkgo teas
Total phenolic content and antioxidant capacity (FRAP method) of Ginkgo biloba L. leaves and of different commercial ginkgo teas were determined and compared. Different water extracts (infusions and decoctions) were prepared varying the time of infusing, boiling, and steeping, and also aqueous ethanolic (water/ethanol 80/20 v/v) extract was made.
Total phenolic contents and FRAP values of collected ginkgo leaves were similar to those of commercial ginkgo mono teas, while these parameters were significantly higher for ginkgo teas containing ginseng or green tea. Decoction was more effective than infusion for extracting antioxidative compounds, in contradiction to suggested preparation methods by the producers. Aqueous ethanolic extracts had significantly higher total phenolic content and antioxidant capacity than water extracts. The correlation between phenolic content and FRAP values was very strong and positive for water extracts of collected leaves, while it was weak and negative for the tea products
Kinetics of four-wave mixing for a 2D magneto-plasma in strong magnetic fields
We investigate the femtosecond kinetics of an optically excited 2D
magneto-plasma at intermediate and high densities under a strong magnetic field
perpendicular to the quantum well (QW). We assume an additional weak lateral
confinement which lifts the degeneracy of the Landau levels partially. We
calculate the femtosecond dephasing and relaxation kinetics of the laser pulse
excited magneto-plasma due to bare Coulomb potential scattering, because
screening is under these conditions of minor importance. In particular the
time-resolved and time-integrated four-wave mixing (FWM) signals are calculated
by taking into account three Landau subbands in both the valance and the
conduction band assuming an electron-hole symmetry. The FWM signals exhibit
quantum beats mainly with twice the cyclotron frequency. Contrary to general
expectations, we find no pronounced slowing down of the dephasing with
increasing magnetic field. On the contrary, one obtains a decreasing dephasing
time because of the increase of the Coulomb matrix elements and the number of
states in a given Landau subband. In the situation when the loss of scattering
channels exceeds these increasing effects, one gets a slight increase at the
dephasing time. However, details of the strongly modulated scattering kinetics
depend sensitively on the detuning, the plasma density, and the spectral pulse
width relative to the cyclotron frequency.Comment: 13 pages, in RevTex format, 10 figures, Phys. Rev B in pres
Investigation of Integrated Twin Corner Reflectors Designed for 3-D InSAR Applications
There are potentially dangerous areas where InSAR technology cannot be applied routinely in the absence of proper persistent or distributed scatterers. Here, we planned and investigated the use of truncated trihedral triangle corner reflectors (CRs) oriented to ascending and descending directions for Sentinel-1 orbit, which were mounted on the optimal concrete basement including an additional global navigation satellite system (GNSS) adapter. These integrated benchmarks were designed to produce a signal-to-clutter ratio of about 100 (i.e., 20 dB). The mechanical design allows optimal orientation of the reflectors and resistance against dynamic effects. We investigated 1:5 models of the CRs and integrated benchmarks in an anechoic chamber to estimate the effects of truncation and the interference of the twin reflectors. The main effect of the interference is the asymmetric monostatic radar cross section, which can be neglected. The integrated benchmarks were also investigated in two recent landslide areas in Hungary using Sentinel-1 single look complex (SLC) scenes, which confirmed that the preliminary requirements can be met
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