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751.
Open data strategies are being adopted in disaster-related data particularly because of the need to provide information on global targets and indicators for implementation of the Sendai Framework for Disaster Risk Reduction 2015–2030. In all phases of disaster risk management including forecasting, emergency response and post-disaster reconstruction, the need for interconnected multidisciplinary open data for collaborative reporting as well as study and analysis are apparent, in order to determine disaster impact data in timely and reportable manner. The extraordinary progress in computing and information technology in the past decade, such as broad local and wide-area network connectivity (e.g. Internet), high-performance computing, service and cloud computing, big data methods and mobile devices, provides the technical foundation for connecting open data to support disaster risk research. A new generation of disaster data infrastructure based on interconnected open data is evolving rapidly. There are two levels in the conceptual model of Linked Open Data for Global Disaster Risk Research (LODGD) Working Group of the Committee on Data for Science and Technology (CODATA), which is the Committee on Data of the International Council for Science (ICSU): data characterization and data connection. In data characterization, the knowledge about disaster taxonomy and data dependency on disaster events requires specific scientific study as it aims to understand and present the correlation between specific disaster events and scientific data through the integration of literature analysis and semantic knowledge discovery. Data connection concepts deal with technical methods to connect distributed data resources identified by data characterization of disaster type. In the science community, interconnected open data for disaster risk impact assessment are beginning to influence how disaster data are shared, and this will need to extend data coverage and provide better ways of utilizing data across domains where innovation and integration are now necessarily needed. 相似文献
752.
Alan T. Murray Jing Xu Zifan Wang Richard L. Church 《International journal of geographical information science》2019,33(5):1106-1130
An essential location analytic method is GIS, able to support map-based display along with geographic data creation, management, manipulation in addition to functions for suitability evaluation. Location models have proven to be critical as well, with many prominent approaches found in popular GIS software. This paper reviews a class of location models and provides an overview of the methods used to solve these models. This is significant because of the broad use and application of location models in GIS to address important problems and issues facing society. Spatial analytical insights are essential. The implications of models and methods available through GIS are explored, particularly notions of solution quality. Case studies are offered to highlight ease of access to location models in GIS along with observed computational performance. 相似文献
753.
We study the effect of eccentricity and inclination on small amplitude librations around the equilibrium points L
4 and L
5 in the circular restricted three-body problem. We show that the effective libration centres can be displaced appreciably
from the equilateral configuration. The secular extrema of the eccentricity as a function of the argument of pericentre are
shifted by ∼25 °
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
754.
M. R. Truss J. R. Murray G. A. Wynn R. G. Edgar 《Monthly notices of the Royal Astronomical Society》2000,319(2):467-476
We present a numerical scheme for the evolution of an accretion disc through a dwarf nova outburst. We introduce a time-varying artificial viscosity into an existing smoothed particle hydrodynamics code optimized for two- and three-dimensional simulations of accretion discs. The technique gives rise to coherent outbursts and can easily be adapted to include a complete treatment of thermodynamics. We apply a two-dimensional isothermal scheme to the system SS Cygni, and present a wide range of observationally testable results. 相似文献
755.
J. C. Pickering A. P. Thorne J. E. Murray U. Litzén S. Johansson V. Zilio J. K. Webb 《Monthly notices of the Royal Astronomical Society》2000,319(1):163-167
The quality of astronomical spectroscopic data now available is so high that interpretation and analysis are often limited by the uncertainties of the laboratory data base. In particular, the limit with which space–time variations in the fine structure constant α can be constrained using quasar spectra depends on the availability of more accurate laboratory rest wavelengths. We recently measured some transitions in magnesium by high-resolution Fourier transform spectroscopy for this purpose, and we now report measurements on some ultraviolet resonance lines of Zn ii (2062 and 2026 Å), Cr ii (2066, 2062 and 2056 Å) and Ni ii (1751, 1741, 1709 and 1703 Å). Apart from the last line, which is very weak, the uncertainty of these measurements is 0.002 cm−1 (0.08 må) for the lines around 2000 Å and 0.004 cm−1 (0.12 må) for the lines around 1700 Å. 相似文献
756.
Land-use changes on the Sheyenne Delta in southeastern North Dakota, USA, have prompted research on impacts to the unconfined
Sheyenne Delta aquifer (SDA). This study examines effects of the saline discharge of a flowing artesian well that taps the
Dakota aquifer (DAK) on SDA groundwater chemistry and soil salinity. Objectives were to map the saline plume in the SDA using
induction techniques, to assess chloride migration in the SDA, and to evaluate induction sensitivity to moderately saline
sands. Induction data, collected in a 2.9-ha grid, were compared to 31 soil profiles analyzed for gravimetric moisture, electrical
conductivity, and chloride. Soil salinization is widespread, but only 7% of the area meets the 4-dS/m threshold for saline
soils. SDA chloride distribution was determined on transects oriented with and perpendicular to the flow path determined from
induction readings. Chloride was detected in the aquifer 550 m from the source, indicating a transport rate of 21 m/yr. Complex
recharge and discharge patterns and hummocky relief contribute to a wide chloride plume at this site. A mass balance based
on soil-water content and chloride concentration shows that only 4% of the chloride from the DAK well remains in the grid
volume.
Received, January 1998 · Revised, January 1999 · Accepted, March 1999 相似文献
757.
Small-scale fluctuations in acoustic and physical properties in surficial carbonate sediments and their relationship to bioturbation 总被引:1,自引:0,他引:1
Measurements of physical and acoustic properties within the top 40 cm of sediment indicate that there are three classes of
parameter variability relevant to acoustic bottom scattering at the Marquesas Keys and Dry Tortugas sites. The three classes
of variability, spatially and temporally different in terms of scale, are generated by biological and physical processes acting
on sediments. Interplay of bioturbation, trawling and storm events create fine laminations of sand–silt–clay and high gravel-size
mollusk shell content at the Marquesas Keys site; the predominance of biological processes creates strong surficial gradients
and lateral variability in sediment properties at the Dry Tortugas site. 相似文献
758.
Summary. Erosion of continental crust has two effects on surface heat flow: a decrease due to the removal of heat-producing elements, and an increase due to the movement of hot rock towards the surface. In an orogenic belt, where erosion may remove tens of kilometres of material, these effects are important over time-spans comparable with the life of the belt as an elevated region.
An expression is derived which relates surface heat flow to time, heat flow through the deep lithosphere, the distribution of heat sources and the amount and time constant of erosion. The variability of crustal processes permits wide ranges of values for these parameters and geologically reasonable parametral combinations can readily be found which satisfy the surface heat flow observations. These combinations can account for the long time-scale of surface heat flow decay, and the influence of erosion on 'reduced' heat flow has important consequences. This approach predicts a relationship between reduced heat flow and age which is close to that observed, and a linear relation between surface heat flow and reduced heat flow similar to that reported by Pollack & Chapman. The intercept on q0 – A 0 plots (the reduced heat flow) has a physical meaning which changes with time and should not be interpreted as, for example, the heat flux across the Moho.
We conclude that an important part of the observed variation of surface heat flow with age may be explained by the effects of erosion and the variability of crustal processes. In its range of greatest variation surface heat flow mainly reflects these crustal processes and should not be used to infer directly the thermal development of the subcrustal lithosphere. 相似文献
An expression is derived which relates surface heat flow to time, heat flow through the deep lithosphere, the distribution of heat sources and the amount and time constant of erosion. The variability of crustal processes permits wide ranges of values for these parameters and geologically reasonable parametral combinations can readily be found which satisfy the surface heat flow observations. These combinations can account for the long time-scale of surface heat flow decay, and the influence of erosion on 'reduced' heat flow has important consequences. This approach predicts a relationship between reduced heat flow and age which is close to that observed, and a linear relation between surface heat flow and reduced heat flow similar to that reported by Pollack & Chapman. The intercept on q
We conclude that an important part of the observed variation of surface heat flow with age may be explained by the effects of erosion and the variability of crustal processes. In its range of greatest variation surface heat flow mainly reflects these crustal processes and should not be used to infer directly the thermal development of the subcrustal lithosphere. 相似文献
759.
On the nature of superoutbursts in dwarf novae 总被引:1,自引:0,他引:1
M.R. Truss J.R. Murray G.A. Wynn 《Monthly notices of the Royal Astronomical Society》2001,324(1):L1-L5
We determine a crucial feature of the dark halo density distribution from the fact that the luminous matter dominates the gravitational potential at about one disc scalelength R d , but at the optical edge the dark matter has already become the main component of the galaxy density. From the kinematics of 137 spirals we find that the dark matter halo density profiles are self-similar at least out to R opt and show core radii much larger than the corresponding disc scalelengths. The luminous regions of spirals consist of stellar discs embedded in dark haloes with roughly constant density. This invariant dark matter profile is very difficult to reconcile with the fundamental properties of the density distribution of cold dark matter haloes. With respect to previous work, the present evidence is obtained by means of a robust method and for a large and complete sample of normal spirals. 相似文献
760.