Direct Sequential Simulation and Cosimulation   总被引：7，自引：0，他引：7  

Amilcar Soares 《Mathematical Geology》2001,33(8):911-926

Sequential simulation of a continuous variable usually requires its transformation into a binary or a Gaussian variable, giving rise to the classical algorithms of sequential indicator simulation or sequential Gaussian simulation. Journel (1994) showed that the sequential simulation of a continuous variable, without any prior transformation, succeeded in reproducing the covariance model, provided that the simulated values are drawn from local distributions centered at the simple kriging estimates with a variance corresponding to the simple kriging estimation variance. Unfortunately, it does not reproduce the histogram of the original variable, which is one of the basic requirements of any simulation method. This has been the most serious limitation to the practical application of the direct simulation approach. In this paper, a new approach for the direct sequential simulation is proposed. The idea is to use the local sk estimates of the mean and variance, not to define the local cdf but to sample from the global cdf. Simulated values of original variable are drawn from intervals of the global cdf, which are calculated with the local estimates of the mean and variance. One of the main advantages of the direct sequential simulation method is that it allows joint simulation of N _v variables without any transformation. A set of examples of direct simulation and cosimulation are presented.  相似文献   

Lithosphere conductivity structure using the CAM-1 (Lisbon-Madeira) submarine cable     

Fernando A. Monteiro Santos  António Soares  Rita Nolasco  Helena Rodrigues  Rafael Luzio  Nick Palshin  the ISO-D team 《Geophysical Journal International》2003,155(2):591-600

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Diurnal evolution of solar radiation at the surface in the city of São Paulo: seasonal variation and modeling     

A. P. de Oliveira  A. J. Machado  J. F. Escobedo  J. Soares 《Theoretical and Applied Climatology》2002,71(3-4):231-249

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Deep seismic refraction and gravity crustal model and tectonic deformation in Tocantins Province, Central Brazil     

Jesus Berrocal  Yara Marangoni  Nelsí C. de S  Reinhardt Fuck  Jos E.P. Soares  E. Dantas  Fbio Perosi  Celia Fernandes 《Tectonophysics》2004,388(1-4):187

Interpretation of seismic refraction data in the central sector of Tocantins Province, Central Brazil, has produced a seismic crustal model with well-defined upper, intermediate, and lower crust layers having smooth velocity gradient in each layer. The depths to Moho vary from 32 to 43 km, and mean crustal P velocity varies from 6.3 km/s, beneath Goiás magmatic arc on the western side, to 6.4 km/s, below Goiás massif in the central portion and the foreland fold-and-thrust belt on the eastern side. The behaviour of the lower crust layer allows an improved understanding of regional gravimetric features of the central and northern sectors of Tocantins Province and suggests subduction of the Amazon plate in Central Brazil. In the southeastern sector, the refraction experiment resulted in the detection of a thinner crust (38 km) below Brasília fold belt and a thicker crust (41 km) below Paraná basin and São Francisco craton (42 km). The upper crust beneath Paraná Basin is around 20 km thick, whereas it is less than 10 km thick below the craton. These results bring new insights into the geological history of the central and southeastern sectors of Tocantins Province.Gravimetric measurements in the central sector of Tocantins Province delineate a high and a low anomaly separated by a steep gradient with a NE direction. The axis of the gradient seems to bend still further to NE in the northern sector of that province, whereas the gravimetric high continues northwards, defining a separation between them. This suggests that those features belong to different tectonic processes that occurred during Tocantins Province orogenesis. The gravimetric model, which incorporates seismically resolved structure beneath Tocantins Province, better matches the observed gravimetric data.Although tectonic movements have only been monitored with high-precision GPS for short time interval (1999–2001), the results suggest observable deformations. The main seismicity of Central Brazil, the Goiás–Tocantins seismic belt, seems to be spatially associated with the large gravimetric high anomaly and with the observed tectonic deformation.  相似文献   

Freshwater-saltwater interface and estuarine sediment in situ assays based on post-exposure feeding of chironomids and polychaetes     

Sara Soares  Susana Moreira  Sofia Andrade  Lúcia Guilhermino  Rui Ribeiro 《Estuaries and Coasts》2005,28(2):314-319

An integrated approach for ecological and ecotoxicological sediment assessments along the freshwater saltwater interface (FSI) and estuarine areas in general was developed, through the adaptation of recently proposed methods for the midge larvaChironomus riparius (an in situ assay based on post-exposure feeding for sediment toxicity assessments in freshwater systems) and the development of new techniques for the polychaeteHediste (Nereis) diversicolor (an in situ post-exposure feeding assay). Based on the previously proposed methods, improvements were made to the feeding quantification ofC. riparius fourth instar larvae. A method to quantify the post-exposure feeding ofH. diversicolor was developed and optimized under laboratory conditions using newly hatchedArtemia franciscana nauplii as a food source. Assay chambers and procedures fromC. riparius assays were easily adapted forH. diversicolor in situ exposures. Sediment assays using this integrated approach were successfully performed at an uncontaminated river-estuarine system. They consisted of a 48-h exposure followed by a 1-h post-exposure feeding for chironomids and a 2-h post-exposure feeding for polychaetes. Good recovery rates were obtained after the 48-h field exposure. Fluctuations in various physicochemical variables at the FSI, due to the tidal regime, did not significantly influenceC. riparius larval post-exposure feeding rates, suggesting that uncontaminated freshwater sites located upstream of FSI areas can be used as reference sites forC. riparius in situ evaluations in estuaries. Adapted assay chambers and procedures were suitable forH. diversicolor in situ exposures.  相似文献   

Factors influencing human beach choice on three South African beaches: A multivariate analysis   总被引：1，自引：0，他引：1  

A. M. C. De Ruyck  A. G. Soares  A. McLachlan 《GeoJournal》1995,36(4):345-352

Knowledge of recreational use patterns, preferences and opinions of beach users can be useful in developing beaches in such a way as to ensure quality recreational experiences. This paper investigated, by means of questionnaire survey, a) the factors influencing human beach choice on three beaches with different levels of development and b) whether respondents on the different beaches considered different characteristics important on an ideal beach. By means of multiple discriminant analysis, visitors could be classified according to the beaches they were interviewed on, based solely on the different reasons given for visiting the beach as well as on the characteristics they considered important on a beach.Although factors relating to level of beach development were the most important in influencing beach choice on highly developed King's Beach and undeveloped Sardinia Bay, traditional/historical, socio-economic factors and accessibility (all unrelated to beach development) were more important on semi-developed Joorst Park, visited by people of a lower-socio-economic level. These people considered Joorst Park underdeveloped but were prevented by socio-economic restraints from visiting a beach of their choice, eg King's Beach. The highly and semi-developed beaches were visited for their facilities, social activities and accessibility. The undeveloped beach was visited for experiencing nature, peace and quiet, its few people and because dogs were allowed there. In addition, respondents' opinions were obtained on litter, additional facilities, preferred distances between groups on the beach and in the surf and whether dogs and off-road vehicles should be allowed on beaches. More basic facilities (toilets and refuse bins) were considered necessary on all beaches, especially on the semi-developed beach. Beyond a minimal level of amenities, additional comforts were undesired by users on the undeveloped beach and limited funds should rather be used to upgrade and improve beaches such as Joorst Park, that are already developed to attract people with greater demands for a wider range of facilities. However, beaches with different levels of development are necessary to cater for people who desire different recreational experiences. Limiting beach access beyond a certain number of visitors seems to be unpopular with the public.  相似文献   

Motional induction voltage measurements in estuarine environments: the Ria de Aveiro Lagoon (Portugal)     

Rita Nolasco  António Soares  João M. Dias  Fernando A. Monteiro Santos  N. A. Palshin  Patricia Represas  Nuno Vaz 《Geophysical Journal International》2006,166(1):126-134

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Valorization of coffee byproducts for bioethanol production using lignocellulosic yeast fermentation and pervaporation     

D. Dadi  A. Beyene  K. Simoens  J. Soares  M. M. Demeke  J. M. Thevelein  K. Bernaerts  P. Luis  B. Van der Bruggen 《International Journal of Environmental Science and Technology》2018,15(4):821-832

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Changes in physicochemical properties of biodiesel after degradation and remediation     

V. F. Mello  T. C. Soares  M. G. Fonseca  L. N. Batista 《International Journal of Environmental Science and Technology》2018,15(8):1713-1718

Biodiesel is the main substitute for petrodiesel being constituted by several alkyl esters including unsaturated compounds. It can undergo partial oxidation when stored for long periods and transported over long distances. The aims of this study were to analyze the impact of the oxidation process on the physicochemical properties of biodiesel and its remediation through distillation and esterification. Due to its high susceptibility to oxidation, sunflower biodiesel was used as a model. Specific mass, cloud point, cold filter plugging point, oxidation stability and iodine value were the properties analyzed. The results revealed that the treatments affected each sample differently, and in some cases the product after remediation had properties close to or even better than the initial biodiesel. The results reported here indicate that although biodiesel undergoes degradation during storage and transport, this does not mean the affected fuel cannot be marketed. Some important properties can be recovered with simple treatment.  相似文献   

Optimized History Matching with Direct Sequential Image Transforming for Non-Stationary Reservoirs     

M. Helena Caeiro  Vasily Demyanov  Amilcar Soares 《Mathematical Geosciences》2015,47(8):975-994

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