Tracing and using data lineage for pipeline processing in Astro-WISE     

Johnson Mwebaze  Danny Boxhoorn  Edwin A. Valentijn 《Experimental Astronomy》2013,35(1-2):131-155

Most workflow systems that support data provenance primarily focus on tracing lineage of data. Data provenance by data lineage provides the derivation history of data including information about services and input data that contributed to the creation of a data product. We show that tracing lineage by means of full backward chaining not only enables users to share, discover and reuse the data, but also supports scientific data processing through storage, retrieval and (re)processing of digitized scientific data. In this paper, we present Astro-WISE, a distributed system for processing, analyzing and disseminating wide field imaging astronomical data. We show how Astro-WISE traces lineage of data and how it facilitates data processing, retrieval, storage and archiving. Particularly we show how it solves issues related to the changing data items typical for the scientific environment, such as physical changes in calibrations, our insight in these changes and improved methods for deriving results.  相似文献   

Comparison of ground-based and Viking Orbiter measurements of Martian water vapor: Variability of the seasonal cycle     

Bruce M. Jakosky  Edwin S. Barker 《Icarus》1984,57(3):322-334

Earth-based observations of Mars atmospheric water vapor, made from McDonald Observatory, are presented for the 1975–1976, 1977–1978, and 1983 apparitions. Comparisons are made with near-simultaneous spacecraft measurements made from the Viking Orbiter MarsAtmospheric Water Detection experiment during 1976–1978 and with previous Earth-based measurements (made since 1964). Differences occur between the behavior in the different years, and may be related to the Mars climate. Measurements during the southern summer in 1969 indicate a factor of three times as much water as is present at this same season in other years.This difference may have resulted from the sublimation of water from the south polar residual cap upon removal of most or all of the CO₂ ice present; sublimation of all the CO₂ ice during some years could be a result of a greater thermal load being placed on the cap due to the presence of differing amounts of atmospheric dust. If substantiated, the water vapor variability will turn out to be a very sensitive indicator of yearly variability in the Martian climate.  相似文献   

Introduction     

M. Kitamura  E. Budding 《Astrophysics and Space Science》1986,118(1-2):1-2

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Estimating macropore and matrix flow using the hydrograph separation procedure in an experimental forest plot     

Jos Nvar  Donald J. Turton  Edwin L. Miller 《水文研究》1995,9(7):743-753

This study was conducted to estimate macropore space, macropore flow and matrix flow in an experimental forest plot in the Ouachita Mountains of Arkansas. Lateral soil water fluxes and soil capillary potentials were observed in the isolated plot during applied rainfall experiments. Rainfalls were applied 17 times during the period 17 July to 10 October 1991. The subsurface hydrograph separation technique was used to estimate macropore space, macropore flux and matrix flux. The boundary between macropore and matrix flow was statistically determined by covariance analysis. The maximum estimated lateral macropore space was approximately 0.006 (cm³ cm^?3). The maximum estimated lateral macropore and matrix flow were 0.042 and 0.00066 cm s^?1, respectively. This report also emphasizes the need for further research on the hydrograph separation procedure for estimating macropores and macropore flow.  相似文献   

Observation and analysis of some recent Galilean satellite phenomena     

W. H. Allen  M. Loudon  E. Budding 《Earth, Moon, and Planets》1992,58(2):105-114

Five well observed recent mutual phenomena (1 occultation, 4 eclipses) of the Galilean satellites have been analysed and four fitting parameters determined for each event.The times of mid-minima are well determined in all cases (generally to within a second or two), but the separation and velocity parameters depend on the penumbral illumination modelling. For this reason, parameters derived from eclipses are somewhat less well determined than from occultations.Taken together with the dependence on the inherent surface reflection properties of the rearward satellite, the results indicate that Asknes et al.'s (1984) suggestion of order 0.01 arcsec accuracies on positional determinations from mutual phenomena data represents rather a lower limit to the real errors in most cases.  相似文献   

The eclipses of starspots     

E. Budding 《Astrophysics and Space Science》1988,143(1):1-14

Formulae are set out from which the light loss may be derived in a close binary system in which a component affected by a starspot, of the type considered previously (Budding, 1977) is also in eclipse, in such a way that the starspot itself is undergoing eclipse. In this way the hitherto postponed problem of thecombination of eclipse and maculation effects — which are sometimes believed to be present, e.g., in RS CVn-stars — is treated, and shown to be reducible to expressions involving algebraic or elliptic integrals.A more practical approach using a small-spot approximation is given, and demonstrated on an example. Such an approach should be easy to manage by computer, and is expected to find a ready application in the analysis of active cool, close binaries.  相似文献   

Spatial mining of migration patterns from web demographics     

T. Edwin Chow  Ryan T Schuermann  Anne H Ngu  Khila R Dahal 《International journal of geographical information science》2018,32(10):1977-1998

Volunteered Geographic Information, social media, and data from Information and Communication Technology are emerging sources of big data that contribute to the development and understanding of the spatiotemporal distribution of human population. However, the inherent anonymity of these crowd-sourced or crowd-harvested data sources lack the socioeconomic and demographic attributes to examine and explain human mobility and spatiotemporal patterns. In this paper, we investigate an Internet-based demographic data source, personal microdata databases publicly accessible on the World Wide Web (hereafter web demographics), as potential sources of aspatial and spatiotemporal information regarding the landscape of human dynamics. The objectives of this paper are twofold: (1) to develop an analytical framework to identify mobile population from web demographics as an individual-level residential history data, and (2) to explore their geographic and demographic patterns of migration. Using web demographics of Vietnamese–Americans in Texas collected in 2010 as a case study, this paper (1) addresses entity resolution and identifies mobile population through the application of a Cost-Sensitive Alternative Decision Tree (CS-ADT) algorithm, (2) investigates migration pathways and clusters to include both short- and long-distance patterns, and (3) analyze the demographic characteristics of mobile population and the functional relationship with travel distance. By linking the physical space at the individual level, this unique methodology attempts to enhance the understanding of human movement at multiple spatial scales.  相似文献   

The Invasive Species Challenge in Estuarine and Coastal Environments: Marrying Management and Science     

Susan L. Williams  Edwin D. Grosholz 《Estuaries and Coasts》2008,31(1):3-20

Despite the widely acknowledged threat posed by invasive species in coastal estuaries, there are substantial gaps at the intersection of science and policy that are impeding invasive species management. In the face of pressing management needs in coastal and estuarine environments, we advocate that introduced species should receive the kind of management effort dedicated, for example, to reducing pollution. We support our argument with some examples of economic costs of estuarine and coastal introduced species and a summary of recent evidence for the ecological costs. We highlight some of the issues that either thwart or facilitate the successful marriage between science and management of introduced species, including the regulatory framework for management. We use the available information on coastal eradication programs, including case histories of the programs for Caulerpa taxifolia and Spartina alterniflora (and hybrids) in the western USA, to indicate the feasibility of managing introduced species and to help point out how management and science can improve the outcome. We close with a research agenda that focuses primarily on science that will really assist with invasive species management and reflects our own experience and the opinions of managers directly involved with this issue.  相似文献   

Modeling the effects of bond environment on equilibrium iron isotope fractionation in ferric aquo-chloro complexes     

Pamela S. Hill  Edwin A. Schauble 《Geochimica et cosmochimica acta》2008,72(8):1939-1958

Four or five sets of ab initio models, including Unrestricted Hartree Fock (UHF) and hybrid Density Functional Theory (DFT) are calculated for each species in a series of aqueous ferric aquo-chloro complexes: , , , FeCl₃(H₂O)₃, FeCl₃(H₂O)₂, , FeCl₅H₂O²⁻, , ) in order to determine the relative isotopic fractionation among the complexes, to compare the results of different models for the same complexes, to examine factors that influence the magnitude of the isotopic fractionation, and to compare bond-partner-driven fractionation with redox-driven fractionation.Relative to , all models show a nearly linear decrease in ⁵⁶Fe/⁵⁴Fe as the number of Cl⁻ ions per Fe³⁺ ion increases, with slopes of −0.8‰ to −1.0‰ per Cl⁻ at 20 °C. At 20 °C, 1000 ln β (β = ⁵⁶Fe/⁵⁴Fe reduced partition function ratio relative to a dissociated Fe atom) values range from 8.93‰ to 9.73‰ for , 8.04-9.12‰ for , 7.61-8.73‰ for , 7.14-8.25‰ for , and 3.09-4.41‰ for . The fractionation between and ranges from 1.5‰ to 2.6‰, depending on the model; this is comparable in magnitude to fractionation effects due to Fe³⁺/Fe²⁺ redox reactions. β values from the UHF models are consistently higher than those from the hybrid DFT models.Isotopic fractionation is shown to be sensitive to differences in ligand bond stiffness (above), coordination number, bond length, and the frequency of the asymmetric Fe-X stretching vibrational mode, as predicted by previous theoretical studies. Complexes with smaller coordination numbers have higher 1000 ln β (7.46‰, 5.25‰, and 3.48‰ for , ,, respectively, from the B3LYP/6-31G(d) model). Species with the same number of chlorides but fewer waters also show the effect of coordination number on 1000 ln β: (7.46‰ vs. 7.05‰ for FeCl₃(H₂O)₂ vs. FeCl₃(H₂O)₃ and 5.25‰ vs. 4.94‰ for vs. FeCl₅H₂O²⁻ with the B3LYP/6-31G(d) model). As more Fe-Cl bonds substitute for Fe-OH₂ bonds (with a resulting decrease in β), the lengths of the Fe-Cl bonds and the Fe-O bonds increase.Preliminary modeling of shows an Fe³⁺/Fe²⁺ fractionation of 3.2‰ for the B3LYP/6-31G(d) model, in agreement with previous studies. The addition of an explicit outer hydration sphere of 12 H₂O molecules to models of improves agreement with measured vibrational frequencies and bond lengths; 1000 ln β increases by 0.8-1.0‰. An additional hydration sphere around increases 1000 ln β by only 0.1‰.Isotopic fractionations predicted for this simple system imply that ligands present in an aqueous iron environment are potentially important drivers of fractionation, and suggest that significant fractionation effects are likely in other aqueous systems containing sulfides or organic ligands. Fractionation effects due to both speciation and redox must be considered when interpreting iron isotope fractionations in the geological record.  相似文献   

Basic stellar parameter determination for active cool eclipsing binaries     

E. Budding  C. J. Butler  J. G. Doyle  P. B. Etzel  K. Oláh  M. Zeilik  D. Brown 《Astrophysics and Space Science》1996,236(2):215-227

We examine procedures for the determination of reliable parameter sets characterizing stars in short period eclipsing binary systems of later dwarf, generally sunlike, spectral types. These stars have magnetodynamically active components and form a useful extension to the solar laboratory. Their much more rapid rotation than that of the Sun implies correspondingly enhanced indications of activity-particularly with relatively large maculation effects in broadband data.We concentrate on five such systems, for which we discuss new data and analyses-CG Cyg, ER Vul, YY Gem, BH Vir and UV Psc. Our main aim is to enable more reliable absolute comparisons between the basic properties of such stars and the Sun. Some indications of the ages of these binaries can also provide further pointers to the relative importance of different parameters (e.g. rotation, age, etc.), in determining stellar activity.This article originally appeared as Poster JD12 G42 at the 22nd General Assembly of the IAU, The Hague (van Woerden, 1994).  相似文献