Artificial Intelligence Applications in Transportation Geotechnics   总被引：1，自引：1，他引：0  

A. Gomes Correia  P. Cortez  J. Tinoco  R. Marques 《Geotechnical and Geological Engineering》2013,31(3):861-879

This paper presents a brief overview of artificial intelligence applications in transportation geotechnics, highlighting new approaches and current research directions, including issues related to data mining interpretability and prediction capacities. Several practical applications to earthworks, including the compaction management and quality control aspects of embankments, as well as pavement evaluation, design and management, and the mechanical behaviour of jet grouting material, are presented to illustrate the advantages of using data mining, including artificial neural networks, support vector machines, and evolutionary computation techniques in this domain. This study also propose a novel simplified compaction table for reusing geomaterials and compaction management in embankments and applied one- and two-dimensional advanced sensitivity analyses to better interpret the proposed data-driven models for the prediction of the deformability modulus of jet grouting field samples. These applications show the capabilities of data mining models to address complex problems in transportation geotechnics involving highly nonlinear relationships of data and optimisation needs.  相似文献   

Annual fossil organic carbon delivery due to mechanical and chemical weathering of marly badlands areas     

Yann Graz  Christian Di‐Giovanni  Yoann Copard  Nicolle Mathys  Alexandre Cras  Vincent Marc 《地球表面变化过程与地形》2012,37(12):1263-1271

A key issue in the study of the carbon cycle is constraining the stocks and fluxes in and between C‐reservoirs. Among these, the role and importance of fossil organic carbon (FOC) release by weathering of outcropping sedimentary rocks on continental surfaces is still debated and remains poorly constrained. Our work focuses on FOC fluxes due to chemical and mechanical weathering of marls in two experimental watersheds with typical badlands geomorphology (Draix watersheds, Laval and Moulin, Alpes de Haute Provence, France). Organic matter from bedrock, soil litter and riverine particles are characterized by Rock‐Eval 6 pyrolysis. FOC fluxes due to mechanical weathering are then estimated by monitoring the annual particulate solid exports at the outlets of the watersheds (1985–2005 period). FOC fluxes from chemical weathering were calculated using Ca²⁺ concentrations in dissolved loads (year 2002) to assess the amount of FOC released by the dissolution of the carbonate matrix. Results show that FOC delivery is mainly driven by mechanical weathering, with a yield ranging from 30 to 59 t km^‐2 yr^‐1 in the Moulin (0.08 km²) and Laval (0.86 km²) catchments, respectively, (1985–2005 average). The release of FOC attributed to chemical weathering was 2.2 to 4.2 t km^‐2 for the year 2002. These high FOC fluxes from badlands are similar to those observed in tectonically active mountain catchments. At a regional scale, badland outcropping within the Durance watershed does not exceed 0.25% in area of the Rhône catchment, but could annually deliver 12 000 t yr^‐1 of FOC. This flux could correspond to 27% of the total particulate organic carbon (POC) load exported by the Rhône River to the Mediterranean Sea. At a global scale, our findings suggest that erosion of badlands may contribute significantly to the transfer of FOC from continental surfaces to depositional environments. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

Gully erosion in mountain areas: processes,measurement, modelling and regionalization     

John Wainwright  Nicolle Mathys  Michel Esteves 《地球表面变化过程与地形》2006,31(2):133-134

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Interpretation of fast ripple structure in solar impulsive bursts     

Loran  Jon M.  Brown  John C.  Correia  Emilia  Kaufmann  Pierre 《Solar physics》1985,95(2):363-370

The Helios spacecraft zodiacal light photometers are used to observe the earthward-directed solar mass ejection transient of 27 November, 1979 described by Howard et al. (1982) that completely circles the Sun in coronagraph observations. At this time, Helios B was situated 30° east of the Sun-Earth line at 0.5 AU. The brightness increase moved outward directly along the Sun-Earth line over a period of approximately 24 hr, indicating a strong collimation of the ejection. The outward motion and mass estimates of the ejected material from the photometers compared with near-Earth observations from IMP spacecraft show that at least a portion of the density increase observed at Earth on 29 and 30 November was associated with this ejection.  相似文献   

The sustained yield forest management act and the roots of environmental conflict in Northern New Mexico     

David Correia 《Geoforum》2007,38(5):1040-1051

Recent research on environmental conflict in New Mexico has focused on racial and ethnic conflict between environmentalists and Hispanic loggers as a means to explain the trajectory of environmental struggle and the failure of Hispano/environmentalist coalitions opposing Forest Service management policies. This paper seeks to extend this explanation by considering the constraining role of federal legislation, institutional management and commercial resource exploitation that limited opportunities for Hispano/environmental collaborative challenges to federal resource management arrangements. I analyze the foundations of sustained yield forestry on the Carson National Forest in northern New Mexico though a focus on the legal construction of sustained yield policies and the practices of implementing sustained yield on the Vallecitos Federal Sustained Yield Unit, a special timber production sub-unit of the Carson. The paper illustrates how the deployment of sustained yield forestry in New Mexico produced not only conditions of production favorable to commercial timber operators, but also established a complex and contradictory regulatory environment that effectively constrained collaborative efforts between environmentalists and small-scale loggers in their efforts to construct alternative futures for resource management in the region.  相似文献   

Effects of water-borne copper on metallothionein and lipid peroxidation in the marine amphipod gammarus locusta     

Ana D. Correia  David R. Livingstone  M. Helena Costa 《Marine environmental research》2002,54(3-5)

The aim of the current work was to determine over 10 days the effects of water-borne exposure of the marine amphipod Gammarus locusta to 4 μgCu l⁻¹ on the metallothionein (MT; measured by differential pulse polarography) protection system and lipid peroxidation (LP; thiobarbituric acid-reactive malondialdehyde equivalents) as a measure of oxidative damage. MT levels in exposed animals increased significantly at day 2 (36% > control; P<0.001) and remained high at days 6 and 10 (55 and 38%, respectively, P<0.001). The maximum level of MT at day 6 coincided with the highest Cu body-burden. LP increased within 1 day of exposure, indicative of Cu as an oxidative stressor. However, in contrast to MT, the highest LP level was seen at day 4 (68% > control, P<0.001) before returning to control values by day 6, indicating a protective role of MT against the pro-oxidant effects of Cu.  相似文献   

A multibeam antenna for solar MM-wave burst observations with high spatial and temporal resolution     

R. Herrmann  A. Magun  J. E. R. Costa  E. Correia  P. Kaufmann 《Solar physics》1992,142(1):157-170

In this paper a new method for the determination of the position of microwave burst sources on the Sun, its implementation and first observational results, are presented. The 13.7 m antenna at Itapetinga with a five-channel receiver operating at 48 GHz and with a time resolution of 1 ms is used. Five horn antennas clustered around the focus of the Cassegrain reflector provide 5 beams diverging by about 2. This configuration allows the observation of different parts of an active region and the determination of the center of the burst position with an accuracy of 5 to 20 depending on the angular distance relative to the antenna axis. The field of view is 2 by 4. The time resolution of 1 ms is suitable to search for fast structures at 48 GHz. A total bandwidth of 400 MHz is used in order to achieve a sensitivity of 0.04 s.f.u. sufficient for the detection of weak bursts. First observational results of the flare on May 11, 1991 show a well-located source position during all stages.Paper presented at the 4th CESRA workshop in Ouranopolis (Greece) 1991.  相似文献   

Multiple energetic injections in a strong spike-like solar burst   总被引：1，自引：0，他引：1  

P. Kaufmann  E. Correia  J. E. R. Costa  B. R. Dennis  G. J. Hurford  J. C. Brown 《Solar physics》1984,91(2):359-376

An intense and fast spike-like solar burst was observed with high sensitivity in microwaves and hard X-rays, on December 18,1980, at 19^h21^m20^s UT. It is shown that the burst was built up of short time scale structures superimposed on an underlying gradual emission, the time evolution of which showed remarkable proportionality between hard X-ray and microwave fluxes. The finer time structures were best defined at mm-microwaves. At the peak of the event the finer structures repeat every 30–60 ms (displaying an equivalent repetition rate of 16–20 s^-1). The more slowly varying component with a time scale of about 1 s was identified in microwaves and hard X-rays throughout the burst duration. Similarly to what has been found for mm-microwave burst emission, we suggest that X-ray fluxes might also be proportional to the repetition rate of basic units of energy injection (quasi-quantized). We estimate that one such injection produces a pulse of hard X-ray photons with about 4 × 10²¹ erg, for 25 keV. We use this figure to estimate the relevant parameters of one primary energy release site both in the case where hard X-rays are produced primarily by thick-target bremsstrahlung, and when they are purely thermal, and also discuss the relation of this figure to global energy considerations. We find, in particular, that a thick-target interpretation only becomes possible if individual pulses have durations larger than 0.2 s.  相似文献   

Modelling for anchovy recruitment studies in the Gulf of Lions (Western Mediterranean Sea)   总被引：4，自引：4，他引：0  

Amandine Nicolle  Pierre Garreau  Bernard Liorzou 《Ocean Dynamics》2009,59(6):953-968

Anchovy (Engraulis encrasicolus) is an important commercial species and one of the most abundant pelagic fish in the Gulf of Lions and the Catalan Sea. The factors influencing its recruitment are crucial to fisheries and ecological research. Among those factors transport of larvae by hydrodynamics (currents) is important because it determines whether the organisms can reach areas favourable to recruitment or are dispersed. Therefore, the first step in anchovy recruitment modelling is to simulate North-western Mediterranean Sea circulation. Several years (2001–2008) of hydrodynamics were simulated with the MARS-3D code. The resulting simulated currents and salinity are used by Lagrangian tool, Ichthyop, to transport anchovy eggs and larvae to the Western Mediterranean Sea. The aim of this study is to understand the main hydrodynamic processes that control anchovy transport and the effects of diel vertical migration on the transport and final distribution of anchovy.  相似文献   

Probing the high latitude ionosphere from ground-based observations: The state of current knowledge and capabilities during IPY (2007–2009)     

Lucilla Alfonsi  Andrew J. Kavanagh  Ermanno Amata  Pierre Cilliers  Emilia Correia  Mervyn Freeman  Kirsti Kauristie  Ruiyuan Liu  Juha-Pekka Luntama  Cathryn N. Mitchell  G.A. Zherebtsov 《Journal of Atmospheric and Solar》2008,70(18):2293-2308

During the International Polar Year (IPY), one area of great interest is co-coordinated, multi-instrument probing of the ionosphere at high latitudes. This region is important not only for the applications that rely upon our understanding of it, but also because it contains the footprints of processes that have their origin in the interplanetary space. Many different techniques are now available for probing the ionosphere, from radar measurements to the analysis of very low frequency (VLF) wave paths. Combining these methods provides the ability to study the ionosphere from high in the F-region to the bottom of the D-layer. Thus, coupling processes from the magnetosphere and to the neutral atmosphere can be considered. An additional dimension is through comparisons of the response of the two polar ionospheres to similar (or the same) geomagnetic activity. With more instruments available at the South Pole inter-hemispheric, studies have become easier to accomplish such that a fuller picture of the global response to Sun–Earth coupling can be painted.This paper presents a review of the current state of knowledge in ionospheric probing. It cannot provide a comprehensive guide of the work to date due to the scale of the topic. Rather it is intended to give an overview of the techniques and recent results from some of the instruments and facilities that are a part of the IPY cluster 63—Heliosphere Impact on Geospace. In this way it is hoped that the reader will gain a flavor of the recent research performed in this area and the potential for continuing collaboration and capabilities during the IPY (2007–2009).  相似文献