Prediction of Groundwater Level in Ardebil Plain Using Support Vector Regression and M5 Tree Model          下载免费PDF全文

Mohammad Taghi Sattari  Rasoul Mirabbasi  Reza Shamsi Sushab  John Abraham 《Ground water》2018,56(4):636-646

The Ardebil plain, which is located in northwest Iran, has been faced with a recent and severe decline in groundwater level caused by a decrease of precipitation, successive long‐term droughts, and overexploitation of groundwater for irrigating the farmlands. Predictions of groundwater levels can help planners to deal with persistent water deficiencies. In this study, the support vector regression (SVR) and M5 decision tree models were used to predict the groundwater level in Ardebil plain. The monthly groundwater level data from 24 piezometers for a 17‐year period (1997 to 2013) were used for training and test of models. The model inputs included the groundwater levels of previous months, the volume of entering precipitation into every cell, and the discharge of wells. The model output was the groundwater level in the current month. In order to evaluate the performance of models, the correlation coefficient (R) and the root‐mean‐square error criteria were used. The results indicated that both SVR and M5 decision tree models performed well for the prediction of groundwater level in the Ardebil plain. However, the results obtained from the M5 decision tree model are more straightforward, more easily applied, and simpler to interpret than those from the SVR. The highest accuracy was obtained using the SVR model to predict the groundwater level from the Ghareh Hasanloo and Khalifeloo piezometers with R = 0.996 and R = 0.983, respectively.  相似文献   

Trapping Ionic Mercury Using Different Adsorbents     

Adedamola Titi Ojedokun  Abraham Olusegun Oluwole  Olugbenga Solomon Bello 《洁净——土壤、空气、水》2019,47(12)

Of recent, adsorption process has gained a lot of attention as a cheap and effective means of removing trace metals from wastewater prior to discharge into water bodies. Being flexible in design and operation, the process has enabled an optimal recovery of trace metals such that the treated effluents meet the desired standards for waste disposal. Mercury is a toxicant released into the environment from natural and anthropogenic sources. It is notorious for having an unusual tendency to bio‐accumulate and persist in the food chain. Presence of mercury in food, especially those of aquatic sources has drastic implications on human health. Therefore, efforts have been made to develop and optimize low‐cost activated carbon (AC) as adsorbents for scavenging mercury from aqueous effluents. Herein, how mercury accumulates across the food chain, its health implications, and the recent advancement in the use of low‐cost ACs as adsorbent for trapping mercury from wastewater are highlighted. Relationship between the mercury removal efficiency and the surface morphology of the adsorbents as well as the influence of prevailing experimental condition on the sorption process were addressed. Challenges and future prospects of the use of low‐cost adsorbents in addressing mercury pollution in the environment are discussed.  相似文献   

Effects of Wormhole Configurations on Performance of Cyclic Solvent Injection in Heavy Oil Systems     

David  Nathan Abraham  Torabi  Farshid 《Natural Resources Research》2019,28(3):1021-1035

Natural Resources Research - In this study, the effect of three different wormhole configurations: single-linear, single-branched, and double-branched wormholes on the performance of cyclic solvent...  相似文献   

Effect of Emission From the Moon on Remote Sensing of Sea Surface Salinity: An Example With the Aquarius Radiometer     

Dinnat  E.P. Abraham  S. Le Vine  D.M. de Matthaeis  P. Jacob  D. 《Geoscience and Remote Sensing Letters, IEEE》2009,6(2):239-243

This letter describes the effect of thermal emission from the Moon on remote sensing of sea surface salinity from space. In most cases, radiation from the Moon is negligible; however, at several times during the lunar cycle, it is possible for radiation to be reflected from the Earth's surface into the main beam of the radiometer antennas. The signal in such cases can be important because of the high radiometric accuracy required to monitor salinity. Examples are presented using the Aquarius orbit and antennas for both smooth and rough ocean surfaces.  相似文献   

Dynamics of triple black hole systems in hierarchically merging massive galaxies     

Loren Hoffman  Abraham Loeb 《Monthly notices of the Royal Astronomical Society》2007,377(3):957-976

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Hubble Space Telescope imaging of the CFRS and LDSS redshift surveys – IV. Influence of mergers in the evolution of faint field galaxies from z∼1     

O. Le Fèvre  R. Abraham  S. J. Lilly  R. S. Ellis  J. Brinchmann  D. Schade  L. Tresse  M. Colless  D. Crampton  K. Glazebrook  F. Hammer  T. Broadhurst 《Monthly notices of the Royal Astronomical Society》2000,311(3):565-575

Hubble Space Telescope images of a sample of 285 galaxies with measured redshifts from the Canada–France Redshift Survey (CFRS) and Autofib–Low Dispersion Spectrograph Survey (LDSS) redshift surveys are analysed to derive the evolution of the merger fraction out to redshifts z ∼1. We have performed visual and machine-based merger identifications, as well as counts of bright pairs of galaxies with magnitude differences δm ≤1.5 mag. We find that the pair fraction increases with redshift, with up to ∼20 per cent of the galaxies being in physical pairs at z ∼0.75–1. We derive a merger fraction varying with redshift as ∝(1+ z )^3.2±0.6, after correction for line-of-sight contamination, in excellent agreement with the merger fraction derived from the visual classification of mergers for which m =3.4±0.6. After correcting for seeing effects on the ground-based selection of survey galaxies, we conclude that the pair fraction evolves as ∝(1+ z )^2.7±0.6. This implies that an average L * galaxy will have undergone 0.8–1.8 merger events from z =1 to z =0, with 0.5 to 1.2 merger events occuring in a 2-Gyr time-span at around z ∼0.9. This result is consistent with predictions from semi-analytical models of galaxy formation. From the simple coaddition of the observed luminosities of the galaxies in pairs, physical mergers are computed to lead to a brightening of 0.5 mag for each pair on average, and a boost in star formation rate of a factor of 2, as derived from the average [O  ii ] equivalent widths. Mergers of galaxies are therefore contributing significantly to the evolution of both the luminosity function and luminosity density of the Universe out to z ∼1.  相似文献   

A performance based approach to dolomite risk management   总被引：1，自引：0，他引：1  

David B. Buttrick  Nicole Y. G. Trollip  Ronald B. Watermeyer  Nicolaas D. Pieterse  Abraham A. Gerber 《Environmental Earth Sciences》2011,64(4):1127-1138

Urban development commonly disturbs the meta-stable conditions in the dolomite environment which can lead to sinkhole formation. 650 sinkholes, which manifested from 1984 to 2004 in an approximately 3,700 ha urbanized environment, located on dolomite land south of Pretoria in South Africa, was analyzed in the absence of risk mitigation measures. A 4 year period post the implementation of a comprehensive risk management system was also analyzed. This research permitted a timely review of the Buttrick et al. (J South African Inst Civil Eng 43(2):27–36, 2001) methodology for dolomite land hazard identification which is commonly used in stability analysis and the development of risk mitigation strategies in Southern Africa. The research confirmed this methodology and demonstrated that the approach to the mitigation of hazards through risk management can improve the hazard rating of dolomite land. The research provided much needed data and insights to refine and expand upon the current South African methodology to cover the full spectrum of developments in a manner which is capable of being included in legislative frameworks governing the development of dolomite land, both locally and internationally.  相似文献   

Using McDaniel's model to represent non-Rayleigh reverberation     

Gu  M. Abraham  D.A. 《Oceanic Engineering, IEEE Journal of》2001,26(3):348-357

Reverberation in low-frequency active sonar systems operating in shallow water has often been observed to follow non-Rayleigh statistical distributions. McDaniel's model, generalized to allow noninteger valued parameters, has shown promise as being capable of accurately representing real data with a minimal parameterization. This paper first derives an exact analytical expression for the cumulative distribution function (CDF) of the generalized McDaniel model and then compares it with numerical inversion of the characteristic function. Both methods are seen to provide adequate and equivalent precision; however the characteristic function inversion method is significantly faster. The latter CDF evaluation technique is then applied to the analysis of simulated and real data to show that, when minimal data are available, McDaniel's model can more accurately represent a wide variety of non-Rayleigh reverberation than the K or Rayleigh mixture models. This result arises from the generality of McDaniel's model with respect to the K-distribution (i.e., the K-distribution P_fa estimate can be dominated by model mismatch error) and to its compact parameterization with respect to the Rayleigh mixture (i.e., the Rayleigh mixture model P_fa estimate is usually dominated by parameter estimation error)  相似文献   

Non-Rayleigh reverberation characteristics near 400 Hz observed on the New Jersey shelf     

Preston  J.R. Abraham  D.A. 《Oceanic Engineering, IEEE Journal of》2004,29(2):215-235

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Morphological classification of the OSU Bright Spiral Galaxy Survey     

L. F. Whyte  R. G. Abraham  M. R. Merrifield  P. B. Eskridge  J. A. Frogel  R. W. Pogge 《Monthly notices of the Royal Astronomical Society》2002,336(4):1281-1286

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