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Landslide susceptibility mapping using machine learning algorithms and comparison of their performance at Abha Basin,Asir Region,Saudi Arabia

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Geoscience Frontiers 2021年第2期12卷 639-655页

作者： Ahmed mohamed Youssef hamid Reza Pourghasemi Geology Department Faculty of ScienceSohag UniversityEgypt Geological Hazards Department Applied Geology SectorSaudi Geological SurveyP.O.Box 54141Jeddah21514Saudi Arabia Department of Natural Resources and Environmental Engineering College of AgricultureShiraz UniversityShirazIran

The current study aimed at evaluating the capabilities of seven advanced machine learning techniques(mLTs),including,Support Vector machine(SVm),Random Forest(RF),multivariate Adaptive Regression Spline(mARS),Artificial Neural Network(ANN),Quadratic Discriminant Analysis(QDA),Linear Discriminant Analysis(LDA),and Naive Bayes(NB),for landslide susceptibility modeling and comparison of their *** machine learning algorithms with spatial data types for landslide susceptibility mapping is a vitally important *** study was carried out using GIS and R open source software at Abha Basin,Asir Region,Saudi ***,a total of 243 landslide locations were identified at Abha Basin to prepare the landslide inventory map using different data *** the landslide areas were randomly separated into two groups with a ratio of 70%for training and 30%for validating *** landslide-variables were generated for landslide susceptibility modeling,which include altitude,lithology,distance to faults,normalized difference vegetation index(NDVI),landuse/landcover(LULC),distance to roads,slope angle,distance to streams,profile curvature,plan curvature,slope length(LS),and *** area under curve(AUC-ROC)approach has been applied to evaluate,validate,and compare the mLTs *** results indicated that AUC values for seven mLTs range from 89.0%for QDA to 95.1%for *** findings showed that the RF(AUC=95.1%)and LDA(AUC=941.7%)have produced the best performances in comparison to other *** outcome of this study and the landslide susceptibility maps would be useful for environmental protection.

关键词： Landslide susceptibility machine learning algorithms Variables importance Saudi Arabia

Effect of gap size on microstructure of transient liquid phase bonded IN-738LC superalloy

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Transactions of Nonferrous metals Society of China 2016年第2期26卷 437-447页

作者： Vahid mALEKI hamid OmIDVAR mohammad-reza RAHImIPOUR Department of mining and metallurgical Engineering Amirkabir University of Technology (Tehran Polytechnic) Department of Ceramic Materials and Energy Research Center

In order to investigate the microstructure evolution and gain complete isothermal solidification time, transient liquid phase （TLP） bonding of IN-738LC superalloy was carried out using powdered AmS 4777 as the filler metal. The influence of gap size and bonding time on the joints was investigated. For example, complete isothermal solidification time for 40μm gap size was obtained as 45 min. In the case of lack of completion of isothermal solidification step, the remained molten interlayer cooled in the bonding zone under non-equilibrium condition andγ–γ′ eutectic phase formed in that area. The relationship between gap size and holding time was not linear. With the increase in gap size, eutectic phase width became thicker. In the diffusion affected zone, a much larger amount of alloying elements were observed reaching a peak. These peaks might be due to the formation of boride or silicide intermetallic. With the increase in gap size, the time required for bonding will increase, so the alloying elements have more time for diffusion and distribution in farther areas. As a result, concentrations of alloying elements decreased slightly with the increase in the gap size. The present bi-phasic model did not properly predict the complete isothermal solidification time for IN-738LC-AmS 4777-IN-738LC TLP bonding system.

关键词： IN-738LC superalloy transient liquid phase (TLP) bonding gap size complete isothermal solidification

Impacts of wind erosion and seasonal changes on soil carbon dioxide emission in southwestern Iran

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Journal of Arid Land 2020年第4期12卷 690-700页

作者： Nadia KAmALI hamid SIROOSI Ahmad SADEGHIPOUR Rangeland Research Division Research Institute of Forests and RangelandsAgricultural ResearchEducation and Extension Organization(AREEO)Tehran 13185116Iran Rangeland Sciences Gorgan University of Agricultural Researches and Natural ResourcesGorgan ***Iran Desert Studies Faculty Semnan UniversitySemnan ***Iran

Wind erosion is one of the main drivers of soil loss in the world, which affects 20 million hectare land of Iran. Besides the soil loss, wind erosion contributes to carbon dioxide emission from the soil into the atmosphere. The objective of this study is to evaluate monthly and seasonal changes in carbon dioxide emission in four classes i.e., low, moderate, severe and very severe soil erosion and the interactions between air temperature and wind erosion in relation to carbon dioxide emission in the Bordekhun region, Boushehr Province, southwestern Iran. Wind erosion intensities were evaluated using IRIFR(Iran Research Institute of Forests and Ranges) model, in which four classes of soil erosion were identified. Afterward, we measured carbon dioxide emission on a monthly basis and for a period of one year using alkali traps in each class of soil erosion. Data on emission levels and erosion classes were analyzed as a factorial experiment in a completely randomized design with twelve replications in each treatment. The highest rate of emission occurred in July(4.490 g CO_2/(m^2·d)) in severely eroded lands and the least in January(0.086 g CO_2/(m^2·d)) in low eroded lands. Therefore, it is resulted that increasing erosion intensity causes an increase in soil carbon dioxide emission rate at severe erosion intensity. moreover, the maximum amount of carbon dioxide emission happened in summer and the minimum in winter. Soil carbon dioxide emission was just related to air temperature without any relationship with soil moisture content;since changes of soil moisture in the wet and dry seasons were not high enough to affect soil microorganisms and respiration in dry areas. In general, there are complex and multiple relationships between various factors associated with soil erosion and carbon dioxide emission. Global warming causes events that lead to more erosion, which in turn increases greenhouse gas emission, and rising greenhouse gases will cause more global warming. The

关键词： alkali trap arid areas global warming IRIFR model soil biology

An accurate model for the thin film flow

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Acta mechanica Sinica 2008年第4期24卷 375-380页

作者： hamid Ait Abderahmane Georgios H.Vatistas Department of mechanical and Industrial Engineering Concordia University 1455 de maisonneuve Blvd West montreal OC H3G 1m8 Canada

This paper deals with the linear stability of a liquid film flowing down an inclined plane. The Navier-Stokes equations were reduced into four evolution equations that describe the development of the film depth, the flow rate, the free surface velocity, and the wall shear stress, using the Karman-Polhausen boundary layer integral method. Thus, we were able to determine the stability threshold and approach well the critical wave number for long waves. The obtained results were found to be in good agreement with the experiments of Liu et al.

关键词： Liquid film Linear stability Flow model

Exchange Coupling and magnetic Behavior of SmCo_(5-x)Sn_x Alloys

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Journal of materials Science & Technology 2011年第3期27卷 218-222页

作者： hamid Zaigham F.Ahmad Khalid Faculty of materials Science and Engineering GIK Institute of Engineering Sciences and Technology

Exchange coupling and magnetic properties of SmCo5 alloys containing different amounts of Sn were investigated in sintered magnets. X-ray diffraction analysis revealed the formation of Sm2Co17 and Sm2Co7 phases in SmCo5 matrix. Exchange coupling mechanism was evaluated by switching field distribution, dcdemagnetization and magnetization curves as function of reverse applied field. Energy product of 59.2 kJ/m3 （7.4 mGOe）, remanent magnetization to maximum magnetization ratio of 0.97 and remanence coercivity to intrinsic coercivity ratio of 1.75 were achieved for 0.2 at.% Sn.

关键词： Nanocomposite magnet Nanocrystalline phases Sintering Exchange interactions

Energy loss optimization of run-off-road wheels applying imperialist competitive algorithm

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Information Processing in Agriculture 2014年第1期1卷 57-65页

作者： hamid Taghavifar Aref mardani Department of mechanical Engineering of Agricultural machinery Faculty of AgricultureUrmia UniversityUrmiaIran

The novel imperialist competitive algorithm(ICA)has presented outstanding fitness on various optimization *** of meta-heuristics has been a dynamic studying interest of the reliability optimization to determine idleness and reliability *** application of a meta-heuristic evolutionary optimization method,imperialist competitive algorithm(ICA),for minimization of energy loss due to wheel rolling resistance in a soil bin facility equipped with single-wheel tester is *** required data were collected thorough various designed experiments in the controlled soil bin *** and global searching of the search space proposed that the energy loss could be reduced to the minimum amount of 15.46 J at the optimized input variable configuration of wheel load at 1.2 kN,tire inflation pressure of 296 kPa and velocity of 2 m/***,genetic algorithm(GA),particle swarm optimization(PSO)and hybridized GA–PSO approaches were benchmarked among the broad spectrum of meta-heuristics to find the outperforming *** was deduced that,on account of the obtained results,ICA can achieve optimum configuration with superior accuracy in less required computational time.

关键词： Imperialist competitive algorithm Genetic algorithm Particle swarm optimization Energy loss Soil bin

Integrity control of an RBmK-1500 fuel rod locally oxidized under a bounding reactivity-initiated accident

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Nuclear Science and Techniques 2019年第1期30卷 133-143页

作者： hamid Boucherit Algirdas Kaliatka Azzedine Lounis Division of Fuel Technology Nuclear Research Center of Draria Lithuanian Energy Institute Science and materials Engineering Laboratory University of Sciences and Technology Houari Boumediene

In 2007, the license for the second reactor unit of the Ignalina nuclear power plant was renewed considering the safety-related modifications introduced in this *** Safety Analysis Report for this reactor unit was prepared with more strict criteria. The bounding reactivityinitiated accident(RIA) performed by the Lithuanian Energy Institute could be mentioned as an example. The performed analysis demonstrated that even when the worst initial conditions and possible uncertainties are considered,the fuel cladding remains intact. However, the analysis was performed assuming a fresh fuel assembly. In this study, an analysis of the fuel rod cladding behavior in the RBmK-1500 reactor following a bounding RIA is performed using the computational codes FEmAXI-6 and RELAP5. The analysis is extended by modeling an oxide layer(nodular corrosion) on the external surface cladding. An uncertainty and sensitivity analysis was performed using a method developed by the Society for Plant and Reactor Safety,employing the Software for Uncertainty and Sensitivity Analyses, in order to evaluate the effect of the oxide layer on the inside and outside fuel rod temperatures. The results of the thermo-mechanical analysis(stress, strain, and enthalpy) for a local oxide layer with a thickness of 70μm show that despite the exceeded limit of allowed linear power density, the fuel rod is under acceptable safety conditions.

关键词： Safety Reactivity-initiated accident Corrosion RBmK-1500 FEmAXI-6 RELAP5 Software for Uncertainty and Sensitivity Analyses (SUSA)

Effects of drought and slope aspect on canopy facilitation in a mountainous rangeland

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Journal of Plant Ecology 2017年第4期10卷 626-633页

作者： mohammad Farzam hamid Ejtehadi Department of Range and Watershed management Faculty of Natural Resources and EnvironmentFerdowsi University of MashhadMashhadIran Department of Biology Faculty of SciencesFerdowsi University of MashhadMashhadIran

Aims Species composition and diversity of the mountainous rangelands are results of interactions between environmental severities,het-erogeneous topography and facilitative effects by nurse *** research was aimed to compare relative effects of these three envi-ronmental variables on the natural vegetation of a mountainous *** a more detailed understanding,effects of four dif-ferent nurse species were separately compared on the various plant growth forms and on two community plant responses(diversity and abundance).methods A mountainous semiarid rangeland was selected in Baharkish,Quchan,Northeast of *** and canopy cover of all plant species were recorded under the canopy of four different shrubs and in open areas,in north and south-facing aspects,and in a normal and a drought *** diversity,total abundance(%cover)and the abundance of different growth forms were used as crite-ria for assessing effects of the environmental *** were arranged in a factorial combination and analyzed by three-way analysis of variance using a GLm *** Findings(i)Drought,aspect and canopy created niche differentiation:annual forbs and shrubs were more affected by drought,whereas geophytes and grasses were more responsive to slope *** of drought and slope aspect were more profound on species diversity,whereas that of canopy facilitation was stronger on plant abundance.(ii)Canopy facili-tation was dependent on severity of the abiotic factors and life history of interacting *** facilitation allowed for the persistence of only annual forbs,but it was disadvantaged during the drought *** community responses to abiotic factors(slope and drought)were more dependent on the plant growth form,while responses to canopy facilitation were more dependent on the morphology and/or ecology of nurse shrubs.(iii)Effect of shrubs was dependent on their morphology and ecology:shrubs with larger canopy area and nitrogen fix

关键词： biotic interactions facilitation slope aspect plant ecology growth forms

A low-power and low-energy flexible GF(p) elliptic-curve cryptography processor

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第9期11卷 724-736页

作者： hamid Reza AHmADI Ali AFZALI-KUSHA School of Electrical and Computer Engineering University of Tehran

We investigate the use of two integer inversion algorithms,a modified montgomery modulo inverse and a Fermat's Little Theorem based inversion,in a prime-field affine-coordinate elliptic-curve *** perform this,we present a low-power/energy GF(p) affine-coordinate elliptic-curve cryptography(ECC) processor design with a simplified architecture and complete flexibility in terms of the field and curve *** design can use either of the inversion *** on the implementations of this design for 168-,192-,and 224-bit prime fields using a standard 0.13 μm CmOS technology,we compare the efficiency of the algorithms in terms of power/energy consumption,area,and calculation *** results show that while the Fermat's theorem approach is not appropriate for the affine-coordinate ECC processors due to its long computation time,the montgomery modulo inverse algorithm is a good candidate for low-energy *** results also show that the 168-bit ECC processor based on the montgomery modulo inverse completes one scalar multiplication in only 0.4 s at a 1 mHz clock frequency consuming only 12.92 μJ,which is lower than the reported values for similar designs.

关键词： Elliptic-curve cryptography(ECC) Prime field montgomery multiplication montgomery inverse Low-energy