Reference data enhancement for geographic information retrieval using linked data   总被引：1，自引：0，他引：1       下载免费PDF全文

Tiago H. V. M. Moura  Clodoveu A. Davis Jr.  Frederico T. Fonseca 《Transactions in GIS》2017,21(4):683-700

Gazetteers are instrumental in recognizing place names in documents such as Web pages, news, and social media messages. However, creating and maintaining gazetteers is still a complex task. Even though some online gazetteers provide rich sets of geographic names in planetary scale (e.g. GeoNames), other sources must be used to recognize references to urban locations, such as street names, neighborhood names or landmarks. We propose integrating Linked Data sources to create a gazetteer that combines a broad coverage of places with urban detail, including content on geographic and semantic relationships involving places, their multiple names and related non‐geographic entities. Our final goal is to expand the possibilities for recognizing, disambiguating and filtering references to places in texts for geographic information retrieval (GIR) and related applications. The resulting ontological gazetteer, named LoG (Linked OntoGazetteer), is accessible through Web services by applications and research initiatives on GIR, text processing, named entity recognition and others. The gazetteer currently contains over 13 million places, 140 million attributes and relationships, and 4.5 million non‐geographic entities. Data sources include GeoNames, Freebase, DBPedia and LinkedGeoData, which is based on OpenStreetMap data. An analysis on how these datasets overlap and complement one another is also presented.  相似文献   

Brazil's premier gold province. Part II: geology and genesis of gold deposits in the Archean Rio das Velhas greenstone belt, Quadrilátero Ferrífero     

Lydia Lobato  Luiz Ribeiro-Rodrigues  Frederico Vieira 《Mineralium Deposita》2001,36(8):808-809

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Post-LGM sedimentation on the outer shelf-upper slope of the northernmost part of the São Paulo Bight, southeastern Brazil     

Michel Michaelovitch de Mahiques  Ilson Carlos Almeida da SilveiraSilvia Helena de Mello e Sousa  Marcelo Rodrigues 《Marine Geology》2002,181(4):387-400

Sedimentary and isotope data as well as ¹⁴C AMS dating on 15 box cores were used to identify the main post-Last Glacial Maximum (LGM) processes in the outer shelf and upper slope of the northernmost part of the São Paulo Bight, southeastern Brazil. Results show slight but significant variations in calcium carbonate, total sulphur and nitrogen contents as well as carbon and oxygen isotope ratios. Sedimentation rates, varying from 5 to 184 mm kyr⁻¹ are controlled by the shelf and upper slope morphology, the Brazil Current meander dynamics, and the Coastal Water offshore motion.  相似文献   

¹³⁷Cs, ⁶⁰Co and ¹²⁵I bioaccumulation by seaweeds from the Angra dos Reis nuclear power plant region     

J.R.D. Guimarães  E. Penna-Franca 《Marine environmental research》1985,16(2):77-93

As part of a broad research program on the behavior of critical radionuclides to be discharged into the sea by the first Brazilian nuclear powerplant, the uptake accumulation and loss of ¹³⁷Cs, ⁶⁰Co and ¹²⁵I by locally abundant seaweed species was studiedUptake in static 12 liter aquarium experiments reached apparent steady-state in 2–7 days (⁶⁰Co and ¹²⁵I) or 2–3 weeks (¹³⁷Cs). Elimination followed a reverse pattern, being comparatively fast for ¹³⁷Cs and slow for ⁶⁰Co and ¹²⁵I. Dry weight bioaccumulation factors (BFs) were variable, falling in the 10¹ range for ¹³⁷Cs, 10³ for ¹²⁵I and 10³–10⁴ for ⁶⁰Co. Various short-term experiments performed over a 16 month period, showed marked temporal variations of ⁶⁰Co BFs for all species.The results demonstrated that the studied species may play an important role in the transfer of the critical radionuclides through local food webs and can be employed as useful monitors for routine or accidental radionuclide releases.  相似文献   

How to evaluate the quality of coarse‐resolution DEM‐derived drainage networks          下载免费PDF全文

Thâmara Martins Ismael Sousa  Adriano Rolim Paz 《水文研究》2017,31(19):3379-3395

The quality of digital elevation model (DEM)‐derived river drainage networks (RDNs) is influenced by DEM quality, basin physical characteristics, scale, and algorithms used; these factors should not be neglected. However, few research studies analyse the different evaluation approaches used in the literature with respect to adequacy, meaning of the results, advantages, and limitations. Focusing on coarse‐resolution networks, this paper reviews the use of these techniques and offers new insights on these issues. Additionally, we propose adaptations for selected metrics and discuss distinct interpretations for the evaluation of RDNs derived at different spatial resolutions (1, 5, 10, 20, and 30 km) considering the Uruguay River basin (206,000 km²) as a case study. The results demonstrate that lumped basin/river characteristics and basin delineation analysis should not be used as evaluation criteria for RDN quality; however, some of these metrics offer useful complementary information. Percentage of the DEM‐derived RDN within a uniform buffer placed around a river network considered as reference and mean separation distance between these two networks are more suitable metrics, but the former is insensitive to serious errors. The change in reference from a fine‐scale network to a coarse‐resolution manual tracing network significantly augments the discrepancy of these largest errors when the mean distance metric was applied, and visual comparison analysis is necessary to interpret the results for other metrics. We recommend the use of the mean distance metric in combination with a detailed visual assessment, the importance of which increases as the resolution coarsens. In both cases, the impact of network quality can be further refined by quantifying the basin shape and river length errors.  相似文献   

The influence of land use/land cover variability and rainfall intensity in triggering landslides: a back-analysis study via physically based models     

Ávila  Frederico F.  Alvalá  Regina C.  Mendes  Rodolfo M.  Amore  Diogo J. 《Natural Hazards》2021,105(1):1139-1161

Natural Hazards - The objective of this study was to use physically based models to carry out a back-analysis of the set of factors that may have influenced slope instability and the consequent...  相似文献   

Tidal variation in a rocky inter‐tidal fish population: the case of white seabream Diplodus sargus juveniles          下载免费PDF全文

Ana Ribeiro Gonçalves  Liliana de Sousa  Pedro Duarte‐Coelho  Vitor Carvalho Almada 《Marine Ecology》2015,36(4):1468-1471

The rocky inter‐tidal habitat is a harsh and fluctuating environment, subject to frequent disturbances. Field observations of juvenile white seabream Diplodus sargus in inter‐tidal rocky habitats were conducted to analyse the spatial distribution and feeding activity of this species in relation to the tidal cycle. The depth at which fish were observed did not change in most tidal phases while feeding activity changed with tidal level, showing the occurrence of tidal migrations and that feeding may be limited by habitat availability in shallow waters and thus be dependent on tidal changes. The present results show the exploitation of available feeding areas in the rocky inter‐tidal by juvenile white seabream, which corroborates the importance of these habitats for the first developmental stages of this fish species.  相似文献   

Determination of the mean H<Emphasis Type="SmallCaps">i</Emphasis> absorption of the intergalactic medium     

A. Aghaee  P. Petitjean  R. Srianand  C. S. Stalin  R. Guimarães 《Journal of Astrophysics and Astronomy》2010,31(2):59-79

In recent years, the Lyman-α forest in quasar spectra has been used, together with N-body simulations, to determine the underlying matter distribution in the intergalactic medium (IGM). One of the key parameters to be known in order to compare observations and numerical simulations is the mean HI absorption in the IGM. To derive the latter, one has first to fit the quasar continuum. We have observed 20 high redshift and highly luminous QSOs (m _V ≤ 17.5 and 2.40 ≤ z _em ≤ 3.91) at intermediate spectral resolution, with either EMMI (ESO Multi-Mode Instrument) on the ESO-NTT telescope or CARELEC at the OHP (Observatoire de Haute-Provence), and applied different methods of determining the QSO continuum to this QSO sample. We have measured the amount of absorption, known as the flux decrement, DA, in the Lyman-α forest for these different methods and compared the results. In addition, we have compared DA values measured along the same lines of sight observed at high and intermediate spectral resolutions. We discuss the systematics resulting from the use of automatic continuum fitting methods.  相似文献   

From Geo-Pragmatics to Derivation Ontologies: New Directions for the GeoSpatial Semantic Web     

Frederico Fonseca  rea Rodriguez 《Transactions in GIS》2007,11(3):313-316

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Soil geochemical prospecting for gold at Marrancos (Northern Portugual)     

A. P. Reis  A. J. Sousa  E. Cardoso Fonseca 《Journal of Geochemical Exploration》2001,73(1)

This paper discusses some geochemical mapping techniques and their effectiveness in detecting of gold and its pathfinder's geochemical anomalies. The study area (Marrancos area) is situated in Northern Portugal. Gold occurs in a quartz breccia with pyrite and arsenopyrite hosted by metamorphic rocks (hornfels) and it is present in these two sulphide minerals as inclusions or disseminated in the crystal lattice. In this area, the geochemical anomalies obtained by isoconcentration mapping of single elements were difficult to interpret. The use of alternative geochemical mapping such as multielement halos (additive halos) proved to be effective in the definition of Au, As, Bi, Sb, Te and Se secondary geochemical signature.  相似文献