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61.
In this research, the simulation of Urmia Lake water level fluctuation by means of two models was applied. For this, Support Vector Machines (SVM), and Neural Wavelet Network (NWN) models that conjugated both the wavelet function and ANN, developed for simulating the Urmia Lake water level fluctuation. The yearly data of rainfall, temperature and discharge to the Urmia Lake and water level fluctuation were used. Urmia Lake is the biggest and the hyper saline lake in Iran. The outcome of the SVM based models are compared with the NWN. The results of SVM model performs better than NWN and offered a practical solution to the problem of water level fluctuation predictions. Analysis results showed that the optimal situation occurred with use of precipitation, temperature and discharge for all station and water level fluctuations at the lag time of one year (RMSEs) of 0.23, 0.41 m obtained by SVM, NWN, respectively, and SSEs of 0.43, 1.33 and R 2 of 0.97, 0 obtained by SVM, NWN, respectively. The results of SVM model show better accuracy in comparison with the NWN model. 相似文献
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Free fluid porosity and rock permeability, undoubtedly the most critical parameters of hydrocarbon reservoir, could be obtained by processing of nuclear magnetic resonance (NMR) log. Despite conventional well logs (CWLs), NMR logging is very expensive and time-consuming. Therefore, idea of synthesizing NMR log from CWLs would be of a great appeal among reservoir engineers. For this purpose, three optimization strategies are followed. Firstly, artificial neural network (ANN) is optimized by virtue of hybrid genetic algorithm-pattern search (GA-PS) technique, then fuzzy logic (FL) is optimized by means of GA-PS, and eventually an alternative condition expectation (ACE) model is constructed using the concept of committee machine to combine outputs of optimized and non-optimized FL and ANN models. Results indicated that optimization of traditional ANN and FL model using GA-PS technique significantly enhances their performances. Furthermore, the ACE committee of aforementioned models produces more accurate and reliable results compared with a singular model performing alone. 相似文献
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The unique (1954–1956) photoelectric B and V light curves of the EB‐type eclipsing variable FU Ara are here analyzed. The Wilson‐Devinney Differential Correction program was used and the analysis of the results shows that the best fit was obtained at photometric mass ratio q = 0.399 and inclination i = 83°, the primary minimum shows a transit. The star is a semi‐detached system with the secondary that accurately fills its limiting lobe. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
64.
Surface wave dispersion curves from microearthquakes are used to obtain group velocity dispersion maps. The calculation of the local dispersion curves for each grid point from these maps then produces the input data to retrieve the 3D shear wave velocity model of the Tehran region. The group velocity maps indicate that the tomographic results agree well with the three main tectonic features and the geological units in the study area. The tomographic maps generally possess high-velocity structures across most of the mountain belts (Central Alborz and east-southeast mountains), whereas the Tehran Basin correlates to a low-velocity structure. Increasing the period in the study area highlights four independent low-velocity zones that reflect faults and fault junction systems. The shear wave velocity profiles indicate that the depth to bedrock exhibits southward variation ranging from ~?300 m to ~?1500 m. We also focus our analysis on the existence of faults within the shear wave profiles and discuss the low shear wave velocity anomalies deeper than 2 km result from the main fault structures (e.g., North Tehran, North-South Rey and Parchin). Furthermore, we argue that the dip angle of the North Tehran fault varies along fault strike, whereas the North-South Rey fault possesses a constant dip angle. Moreover, initial model uncertainties and checkerboard resolution tests are used to identify reliable and robust anomaly features in the 3D shear wave velocity model and 2D tomographic maps, respectively. Microearthquake analysis provides an effective approach for studying the upper crustal structure heterogeneity, especially the fault structure, of the Tehran region. 相似文献
65.
Prediction of River Stage-Discharge Process Based on a Conceptual Model Using EEMD-WT-LSSVM Approach
Farhad Alizadeh Gharamaleki Alireza Faregh Jalilzadeh Mojtaba Akhoundzadeh Ali 《Water Resources》2020,47(1):41-53
Water Resources - This study proposed a hybrid pre-processing approach along with a conceptual model to enhance the accuracy of river discharge prediction. In order to achieve this goal, Ensemble... 相似文献
66.
Mansourpoor Mojtaba Azin Reza Osfouri Shahriar Izadpanah Amir Abbas Saboori Rahmatallah 《Natural Resources Research》2019,28(4):1609-1617
Natural Resources Research - In this work, we studied the feasibility of using disulfide oil (DSO) as a solvent for wax prevention in pipelines. Several tests were carried out to determine the... 相似文献
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In this paper, a mathematical model is presented for the analysis of dynamic fracture propagation in the saturated porous media. The solid behavior incorporates a discrete cohesive fracture model, coupled with the flow in porous media through the fracture network. The double‐nodded zero‐thickness cohesive interface element is employed for the mixed mode fracture behavior in tension and contact behavior in compression. The crack is automatically detected and propagated perpendicular to the maximum effective stress. The spatial discretization is continuously updated during the crack propagation. Numerical examples from the hydraulic fracturing test and the concrete gravity dam show the capability of the model to simulate dynamic fracture propagation. The comparison is performed between the quasi‐static and fully dynamic solutions, and the performance of two analyses is investigated on the values of crack length and crack mouth opening. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
69.
A new CCD (V) light curve is presented for'the semi-detached binary system FU Ara. The light curve, obtained in 2007, is the first one since the last 50 years. With our data we were able to determine six new times of minimum light and refined the period of the system to 0.8645049 days. A Wilson-Devinney analysis leads to a solution of a semi-detached configuration, composed of a main-sequence primary component of spectral type F5, fractionally smaller than its Roche lobe, and an evolved secondary component of spectral type K I which fills its Roche lobe, and which is overluminous and oversized as compared with the main-sequence. The two components of FU Ara differ considerably in effective temperature. It is classified as an FO Virginis type of near-contact binary system. Assuming a reasonable value for the mass of the primary component, an estimate of the absolute elements of FU Ara has been made, on the assumption that the primary has a mass corresponding to its spectral type according to Svechnikov & Taidakova. 相似文献
70.
Zare MR Mostajaboddavati M Kamali M Abdi MR Mortazavi MS 《Marine pollution bulletin》2012,64(9):1956-1961
The natural radioactivity levels in sediment samples of the northern coast of Oman Sea, covering the coastal strip from Hormoz canyon to Goatr seaport, as the first time has been determined. The results of measurements will serve as background reference level for Oman Sea coastlines. Sediments from 36 coastal and near shore locations were collected for analysis. Analysis on the collected samples were carried out to determine (235)U, (238)U, (232)Th, (40)K and (137)Cs using two high purity germanium detectors with 38.5% and 55% relative efficiencies. The concentration of (235)U, (238)U, (232)Th, (40)K and (137)Cs in sediment samples ranged between 1.01 and 2.87Bq/kg, 11.83 and 22.68Bq/kg, 10.7 and 25.02Bq/kg, 222.89 and 535.07Bq/kg and 0.14 and 2.8Bq/kg, respectively. The radium equivalent activity was well below the defined limit of 370Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. 相似文献