38 research outputs found
Improvement of information support for formation of management reporting on the example of the activities of an energy company
The purpose of the study is to develop a system for generating management reporting on the production activities of an energy company on the SAP Business Objects Platform. To build a reporting system, the following tasks has been set and solved: the conceptual and datalogical models of the data warehouse were created, data areas have been selected from the general data model, the data warehouse has been designed and developed, universes for report groups have been created, a mechanism for integrating data with the data warehouse has been implemented.The paper analyses the information and technological infrastructure of an energy company as well as formulates the basic requirements for the system being created for generating reporting. Two main subsystems have been designed: data storage and integration. The process of implementing the designed subsystems in physical form has been described using the appropriate software products: SAP Hana, SAP Universe Designer, SAP Data Services, SAP Business Intelligence.Thanks to the configured system through the corporate data bus, a relatively simple data integration mechanism became possible. In its information and technological architecture, the company managed to simulate an acceptable data warehouse model and set up the appropriate data flows. A complex data warehouse model has been implemented, and a convenient platform for further data processing has been provided. A clear data integration scheme is configured using SAP Data Services, with the ability to scale and configure the data loading schedule. The developed system has been put into operation and is used by employees to make management decisions within the framework of their professional activities
THE MAIN DIRECTIONS OF THE DIGITAL PROFILE CONCEPT DEVELOPMENT. FOREIGN EXPERIENCE AND DEVELOPMENT PROSPECTS
An approach to solving a comlex and urgent problem facing state and near-state agencies has been described: to provide popular modern services to citizens, while reducing operating costs through the use of digital technologies to improve citizen service and develop more effective ways to work. At the moment, this is achievable by developing a unified information base for the provision of public services, based on the creation of a digital citizen profile. A comparative review of international experience in the field of digitalization of the process of interaction between citizens and government structures has been presented. In accordance with the digitalization programs launched in many countries almost simultaneously, many commercial and social projects are being developed. All of them become available when using complex analytical tools for processing Big data and a Unified identification and authentication system
The Active Corona of HD 35850 (F8 V)
We present Extreme Ultraviolet Explorer spectroscopy and photometry of the
nearby F8 V star HD 35850 (HR 1817). The EUVE spectra reveal 28 emission lines
from Fe IX and Fe XV to Fe XXIV. The Fe XXI 102, 129 A ratio yields an upper
limit for the coronal electron density, log n < 11.6 per cc. The EUVE SW
spectrum shows a small but clearly detectable continuum. The line-to-continuum
ratio indicates approximately solar Fe abundances, 0.8 < Z < 1.6. The resulting
emission-measure distribution is characterized by two temperature components at
log T of 6.8 and 7.4. The EUVE spectra have been compared with non-simultaneous
ASCA SIS spectra of HD 35850. The SIS spectrum shows the same temperature
distribution as the EUVE DEM analysis. However, the SIS spectral firs suggest
sub-solar abundances, 0.34 < Z < 0.81. Although some of the discrepancy may be
the result of incomplete X-ray line lists, we cannot explain the disagreement
between the EUVE line-to-continuum ratio and the ASCA-derived Fe abundance.
Given its youth (t ~ 100 Myr), its rapid rotation (v sin i ~ 50 km/s), and its
high X-ray activity (Lx ~ 1.5E+30 ergs/s), HD 35850 may represent an activity
extremum for single, main-sequence F-type stars. The variability and EM
distribution can be reconstructed using the continuous flaring model of Guedel
provided that the flare distribution has a power-law index of 1.8. Similar
results obtained for other young solar analogs suggest that continuous flaring
is a viable coronal heating mechanism on rapidly rotating, late-type,
main-sequence stars.Comment: 32 pages incl. 14 figures and 3 tables. To appear in the 1999 April
10 issue of The Astrophysical Journa
Recent Advances in Understanding Particle Acceleration Processes in Solar Flares
We review basic theoretical concepts in particle acceleration, with
particular emphasis on processes likely to occur in regions of magnetic
reconnection. Several new developments are discussed, including detailed
studies of reconnection in three-dimensional magnetic field configurations
(e.g., current sheets, collapsing traps, separatrix regions) and stochastic
acceleration in a turbulent environment. Fluid, test-particle, and
particle-in-cell approaches are used and results compared. While these studies
show considerable promise in accounting for the various observational
manifestations of solar flares, they are limited by a number of factors, mostly
relating to available computational power. Not the least of these issues is the
need to explicitly incorporate the electrodynamic feedback of the accelerated
particles themselves on the environment in which they are accelerated. A brief
prognosis for future advancement is offered.Comment: This is a chapter in a monograph on the physics of solar flares,
inspired by RHESSI observations. The individual articles are to appear in
Space Science Reviews (2011
Ultracool dwarfs in Gaia DR3
Aims. In this work we use the Gaia DR3 set of ultracool dwarf candidates and
complement the Gaia spectrophotometry with additional photometry in order to
characterise its global properties. This includes the inference of the
distances, their locus in the Gaia colour-absolute magnitude diagram and the
(biased through selection) luminosity function in the faint end of the Main
Sequence. We study the overall changes in the Gaia RP spectra as a function of
spectral type. We study the UCDs in binary systems, attempt to identify
low-mass members of nearby young associations, star forming regions and
clusters, and analyse their variability properties. Results. We detect 57
young, kinematically homogeneous groups some of which are identified as well
known star forming regions, associations and clusters of different ages. We
find that the primary members of 880 binary systems with a UCD belong mainly to
the thin and thick disk components of the Milky Way. We identify 1109 variable
UCDs using the variability tables in the Gaia archive, 728 of which belong to
the star forming regions defined by HMAC. We define two groups of variable UCDs
with extreme bright or faint outliers. Conclusions. The set of sources
identified as UCDs in the Gaia archive contains a wealth of information that
will require focused follow-up studies and observations. It will help to
advance our understanding of the nature of the faint end of the Main Sequence
and the stellar/substellar transition.Comment: Accepted by Astronomy and Astrophysics. 29 pages, 20 figures plus 3
appendice
Gaia Focused Product Release: A catalogue of sources around quasars to search for strongly lensed quasars
Context. Strongly lensed quasars are fundamental sources for cosmology. The
Gaia space mission covers the entire sky with the unprecedented resolution of
" in the optical, making it an ideal instrument to search for
gravitational lenses down to the limiting magnitude of 21. Nevertheless, the
previous Gaia Data Releases are known to be incomplete for small angular
separations such as those expected for most lenses. Aims. We present the Data
Processing and Analysis Consortium GravLens pipeline, which was built to
analyse all Gaia detections around quasars and to cluster them into sources,
thus producing a catalogue of secondary sources around each quasar. We analysed
the resulting catalogue to produce scores that indicate source configurations
that are compatible with strongly lensed quasars. Methods. GravLens uses the
DBSCAN unsupervised clustering algorithm to detect sources around quasars. The
resulting catalogue of multiplets is then analysed with several methods to
identify potential gravitational lenses. We developed and applied an outlier
scoring method, a comparison between the average BP and RP spectra of the
components, and we also used an extremely randomised tree algorithm. These
methods produce scores to identify the most probable configurations and to
establish a list of lens candidates. Results. We analysed the environment of 3
760 032 quasars. A total of 4 760 920 sources, including the quasars, were
found within 6" of the quasar positions. This list is given in the Gaia
archive. In 87\% of cases, the quasar remains a single source, and in 501 385
cases neighbouring sources were detected. We propose a list of 381 lensed
candidates, of which we identified 49 as the most promising. Beyond these
candidates, the associate tables in this Focused Product Release allow the
entire community to explore the unique Gaia data for strong lensing studies
further.Comment: 35 pages, 60 figures, accepted for publication by Astronomy and
Astrophysic
Gaia Focused Product Release: Radial velocity time series of long-period variables
The third Gaia Data Release (DR3) provided photometric time series of more
than 2 million long-period variable (LPV) candidates. Anticipating the
publication of full radial-velocity (RV) in DR4, this Focused Product Release
(FPR) provides RV time series for a selection of LPVs with high-quality
observations. We describe the production and content of the Gaia catalog of LPV
RV time series, and the methods used to compute variability parameters
published in the Gaia FPR. Starting from the DR3 LPVs catalog, we applied
filters to construct a sample of sources with high-quality RV measurements. We
modeled their RV and photometric time series to derive their periods and
amplitudes, and further refined the sample by requiring compatibility between
the RV period and at least one of the , , or
photometric periods. The catalog includes RV time series and variability
parameters for 9\,614 sources in the magnitude range , including a flagged top-quality subsample of 6\,093 stars
whose RV periods are fully compatible with the values derived from the ,
, and photometric time series. The RV time series
contain a mean of 24 measurements per source taken unevenly over a duration of
about three years. We identify the great most sources (88%) as genuine LPVs,
with about half of them showing a pulsation period and the other half
displaying a long secondary period. The remaining 12% consists of candidate
ellipsoidal binaries. Quality checks against RVs available in the literature
show excellent agreement. We provide illustrative examples and cautionary
remarks. The publication of RV time series for almost 10\,000 LPVs constitutes,
by far, the largest such database available to date in the literature. The
availability of simultaneous photometric measurements gives a unique added
value to the Gaia catalog (abridged)Comment: 36 pages, 38 figure
Gaia Focused Product Release: Asteroid orbital solution: Properties and assessment
Context. We report the exploitation of a sample of Solar System observations based on data from the third Gaia Data Release (Gaia DR3) of nearly 157 000 asteroids. It extends the epoch astrometric solution over the time coverage planned for the Gaia DR4, which is not expected before the end of 2025. This data set covers more than one full orbital period for the vast majority of these asteroids. The orbital solutions are derived from the Gaia data alone over a relatively short arc compared to the observation history of many of these asteroids. Aims. The work aims to produce orbital elements for a large set of asteroids based on 66 months of accurate astrometry provided by Gaia and to assess the accuracy of these orbital solutions with a comparison to the best available orbits derived from independent observations. A second validation is performed with accurate occultation timings. Methods. We processed the raw astrometric measurements of Gaia to obtain astrometric positions of moving objects with 1D sub-mas accuracy at the bright end. For each asteroid that we matched to the data, an orbit fitting was attempted in the form of the best fit of the initial conditions at the median epoch. The force model included Newtonian and relativistic accelerations to derive the observation equations, which were solved with a linear least-squares fit. Results. Orbits are provided in the form of state vectors in the International Celestial Reference Frame for 156 764 asteroids, including near-Earth objects, main-belt asteroids, and Trojans. For the asteroids with the best observations, the (formal) relative uncertainty σa/a is better than 10−10. Results are compared to orbits available from the Jet Propulsion Laboratory and MPC. Their orbits are based on much longer data arcs, but from positions of lower quality. The relative differences in semi-major axes have a mean of 5 × 10−10 and a scatter of 5 × 10−9
Gaia Focused Product Release: Radial velocity time series of long-period variables
Context. The third Gaia Data Release (DR3) provided photometric time series of more than 2 million long-period variable (LPV) candidates. Anticipating the publication of full radial-velocity data planned with Data Release 4, this Focused Product Release (FPR) provides radial-velocity time series for a selection of LPV candidates with high-quality observations. Aims. We describe the production and content of the Gaia catalog of LPV radial-velocity time series, and the methods used to compute the variability parameters published as part of the Gaia FPR. Methods. Starting from the DR3 catalog of LPV candidates, we applied several filters to construct a sample of sources with high-quality radial-velocity measurements. We modeled their radial-velocity and photometric time series to derive their periods and amplitudes, and further refined the sample by requiring compatibility between the radial-velocity period and at least one of the G, GBP, or GRP photometric periods. Results. The catalog includes radial-velocity time series and variability parameters for 9614 sources in the magnitude range 6 ≲ G/mag ≲ 14, including a flagged top-quality subsample of 6093 stars whose radial-velocity periods are fully compatible with the values derived from the G, GBP, and GRP photometric time series. The radial-velocity time series contain a mean of 24 measurements per source taken unevenly over a duration of about three years. We identify the great majority of the sources (88%) as genuine LPV candidates, with about half of them showing a pulsation period and the other half displaying a long secondary period. The remaining 12% of the catalog consists of candidate ellipsoidal binaries. Quality checks against radial velocities available in the literature show excellent agreement. We provide some illustrative examples and cautionary remarks. Conclusions. The publication of radial-velocity time series for almost ten thousand LPV candidates constitutes, by far, the largest such database available to date in the literature. The availability of simultaneous photometric measurements gives a unique added value to the Gaia catalog