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Estimating Weibull Parameters Using Least Squares and Multilayer Perceptron vs. Bayes Estimation

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Computers, Materials & Continua 2022年第5期71卷 4033-4050页

作者： Walid aydi Fuad S.Alduais Department of Computer Science College of Humanities and Science in Al AflajPrince Sattam Bin Abdulaziz UniversityAl-AflajSaudi Arabia Department of Mathematics College of Humanities and Science in Al AflajPrince Sattam Bin Abdulaziz UniversityAl-AflajSaudi Arabia Laboratory of Electronics&Information Technologies Sfax UniversitySfaxTunisia Department of Administration Administrative Science CollegeThamar UniversityYemen

The Weibull distribution is regarded as among the finest in the family of failure distributions.One of the most commonly used parameters of the Weibull distribution(WD)is the ordinary least squares(OLS)technique,which is useful in reliability and lifetime modeling.In this study,we propose an approach based on the ordinary least squares and the multilayer perceptron(MLP)neural network called the OLSMLP that is based on the resilience of the OLS method.The MLP solves the problem of heteroscedasticity that distorts the estimation of the parameters of the WD due to the presence of outliers,and eases the difficulty of determining weights in case of the weighted least square(WLS).Another method is proposed by incorporating a weight into the general entropy(GE)loss function to estimate the parameters of the WD to obtain a modified loss function(WGE).Furthermore,a Monte Carlo simulation is performed to examine the performance of the proposed OLSMLP method in comparison with approximate Bayesian estimation(BLWGE)by using a weighted GE loss function.The results of the simulation showed that the two proposed methods produced good estimates even for small sample sizes.In addition,the techniques proposed here are typically the preferred options when estimating parameters compared with other available methods,in terms of the mean squared error and requirements related to time.

关键词： Weibull distribution maximum likelihood ordinary least squares MLP neural network weighted general entropy loss function

Some Formulas Involving Hypergeometric Functions in Four Variables

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Computer Modeling in Engineering & Sciences 2022年第2期130卷 887-902页

作者： Hassen aydi Ashish Verma Jihad Younis Jung Rye Lee Universit´e de Sousse Institut Sup´erieur D’Informatique etDes Techniques de CommunicationH.Sousse4000Tunisia Department of Mathematics and Applied Mathematics Sefako Makgatho Health Sciences UniversityGa-RankuwaSouth Africa ChinaMedical University Hospital ChinaMedical UniversityTaichung40402Taiwan Department of Mathematics V.B.S.Purvanchal UniversityJaunpur222003India Department of Mathematics Aden UniversityKhormaksarP.o.Box 6014Yemen Department of Data Science Daejin UniversityKyunggi11159Korea

Several(generalized)hypergeometric functions and a variety of their extensions have been presented and investigated in the literature by many authors.In the present paper,we investigate four new hypergeometric functions in four variables and then establish several recursion formulas for these new functions.Also,some interesting particular cases and consequences of our results are discussed.

关键词： Recursion formula quadruple hypergeometric functions pascal identity

Two fuzzy internal model control methods for nonlinear uncertain systems

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International Journal of Intelligent Computing and Cybernetics 2017年第2期10卷 223-240页

作者： Amira.aydi Mohamed Djemel Mohamed Chtourou Department of Electrical Engineering National School of Engineering of SfaxUniversity of SfaxSfaxTunisia

Purpose-The purpose of this paper is to use the internal model control to deal with nonlinear stable systems affected by parametric uncertainties.Design/methodology/approach-The dynamics of a considered system are approximated by a Takagi-Sugeno fuzzy model.The parameters of the fuzzy rules premises are determined manually.However,the parameters of the fuzzy rules conclusions are updated using the descent gradient method under inequality constraints in order to ensure the stability of each local model.In fact,without making these constraints the training algorithm can procure one or several unstable local models even if the desired accuracy in the training step is achieved.The considered robust control approach is the internal model.It is synthesized based on the Takagi-Sugeno fuzzy model.Two control strategies are considered.The first one is based on the parallel distribution compensation principle.It consists in associating an internal model control for each local model.However,for the second strategy,the control law is computed based on the global Takagi-Sugeno fuzzy model.Findings-According to the simulation results,the stability of all local models is obtained and the proposed fuzzy internal model control approaches ensure robustness against parametric uncertainties.Originality/value-This paper introduces a method for the identification of fuzzy model parameters ensuring the stability of all local models.Using the resulting fuzzy model,two fuzzy internal model control designs are presented.

关键词： Robust control Uncertainties Descent gradient method Fuzzy modeling Internal model control Nonlinear systems

On a Ginzburg-Landau Type Energy with Discontinuous Constraint for High Values of Applied Field

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Chinese Annals of Mathematics,Series B 2011年第1期32卷 15-26页

作者： Hassen aydi Université de Monastir Institut Supérieur d'Informatique de MahdiaKm 4Réjiche5121 MahdiaTunisie

In the presence of applied magnetic fields H such that |lnε|《H《1/ε2,the author evaluates the minimal Ginzburg-Landau energy with discontinuous constraint.Its expression is analogous to the work of Sandier and Serf... 详细信息

关键词：应用间断能源 u型 Landau 磁场类似

MEIR-KEELER TYPE CONTRACTIONS FOR TRIPLED FIXED POINTS

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Acta Mathematica Scientia 2012年第6期32卷 2119-2130页

作者： Hassen aydi Erdal Karapvnar Calogero Vetro Universitde Monastir Institut Supérieur d'Informatique de MahdiaRoute de RéjicheKm 4BP 35Mahdia 5121Tunisie Department of Mathematics Atilim University 06836IncekAnkaraTurkey Dipartimento di Matematica e Informatica Universitàdi PalermoVia Archirafi3490123 PalermoItaly

In 2011, Berinde and Borcut [6] introduced the notion of tripled fixed point in partially ordered metric spaces. In our paper, we give some new tripled fixed point theorems by using a generalization of Meir-Keeler con... 详细信息

关键词： tripled fixed point theorems Meir-Keeler type contractions partially or-dered sets

Electrical conductivity and vibrational studies induced phase transition in[N(C_(3)H_(7))_(4)]_(2)ZnBr_(4)compound

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Journal of Advanced Dielectrics 2021年第1期11卷 30-39页

作者： Souad Chkoundali Abdelhedi aydi Laboratory of Multifunctional Materials and Applications(LaMMA)Faculty of Sciences of Sfax University of SfaxB.P.11713000 SfaxTunisia

Bis-Tetrapropylammonium tetrabromozincate was synthesized and characterized by X-ray powder diffraction,as well as vibrational and impedance spectroscopy.Rietveld’s refinement of X-ray diffractogram confirmed the crystallization of the compound through the monoclinic system(space group C_(2/c)).A temperature study of Raman scattering revealed two phase transitions at approximately T_(1)=340 K and T_(2)=393 K.The wavenumber and the line width’s evolution as a function of temperature showed some peculiarities associated with these transitions,which suggests that they are governed by the reorientation of the organic part[N(C_(3)H_(7))_(4)]+.The complex impedance plotted as a double semicircular arc in the studied temperature range and the centers of these semicircles lie below the real axis,which indicates that the material is an on-Debye type.These semicircular arcs are related to the bulk and the grain boundary effects.Furthermore,the alternating current conductivity of[N(C_(3)H_(7))_(4)]_(2)ZnBr_(4)obeyed Jonscher’s law:σ_(AC)(ω)=σ_(dc)+Aω^(s) and the conduction could be attributed to the correlated barrier hopping(CBH)model in both region(I)and(II)and the Non-overlapping Small Polaron Tunneling(NSPT)in region(III).

关键词： Bis-Tetrapropylammonium tetrabromozincate Raman spectroscopy phase transition electrical conductivity conduction mechanism

Hydrogeological Study of the Aquifer System in Central Tunisia: New System Structuring of Horchane Aquifers

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Journal of Water Resource and Protection 2013年第5期5卷 502-510页

作者： Soumaya Chaibi Wanissa.aydi Moncef Chalbaoui Laboratory Water Energy and Environment National School of Engineers of Sfax Sfax City Tunisia

Hydrogeological investigations, tectonics and seismic reflection show the complexity of the Horchane groundwater and drainage possibilities with neighboring groundwater in central Tunisia. Seismic reflection lines intersecting the region show the role of halokinetic movements, by the intrusion along preexisting faults, in the restructuring of the hydrogeological basin. The salt domes associated with a chaotic facies at the base of outcrops, that limit the Horchane basin, puch to outcrops the areas of recharge area. Geoelectric section shows the anisotropy and the importance of Mio-Plio-Quaternary (MPQ) sediment along the gutters, between the outcrops of El Hafay and Kebar on the one hand, and outcrops of Kebar and Majoura on the other. These gutters are communicated with channels that facilitate drainage of the Horchane complex groundwater by that Gammouda in North-East and Braga in East. The results of this study clearly indicate the important role of the geology in the restructuring of groundwater basins, through early halokinetic movements. (i.e. halokinetic movements). The aquifer geometry is controlled by the ascent of Triassic salt material, from the Middle Jurassic, in central Tunisia.

关键词： Groundwater Hydrogeological Basin Halokinetic Movement Aquifer Geometry Water Recharge Drainage Filling Triassic Salt Material

Chemical and Organic Contamination of Phreatic Aquifer of Sidi Bouzid （Center West of Tunisia）

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Journal of Environmental Science and Engineering 2010年第5期4卷 6-13页

作者： S. Chaibi N. Khlif M. Chalbaoui W. aydi Laboratory of Water Environment and Energy Ecole Nationale des Ingenieurs de Sfax. Tunisia Geophysics and Water resources - Faculty of Sciences of Gafsa. Tunisia

An understanding of the long-term changes in the nitrate and microbial contamination pattern of the groundwater of Sidi Bouzid (Centre West of Tunisia) is critical to conservation of drinking water in rural areas supporting mixed land-use activities such as cropping, livestock farming, and residence. The phreatic aquifer was revealed polluted by domestic disposals of the wastewaters in the urban zone. The average nitrate concentration in the groundwater of the east of the mioplioquaternary aquifer of Saddaguia (Sidi Bouzid) rose from 50 mg NO3 - during 1996 to over 100 mg in 2003, which represents an increase of some 10 mg per year. Nitrate groundwater pollution during the period 1996-2003 was the result of the abusive use of fertilizers. In the cultivated zone, we must reduce the effects of the excessive use of the nitrogen fertilizers on the basis of monitoring soil once a year, managing water resources, rationalizing the use of the chemical substances. In urban zones, most of lost wells located in the perimeter reveal the gravity of the state of the aquifer. This last is organically polluted and requires an immediate action for the generalization of the purification network. We need to take into account the reality of under soil in all future planning’s and arrangements. A scheme of sanitation seems necessary before all plans of arrangement. The extension of the sewer network must give the priority to the most vulnerable zones.

关键词：潜水含水层化学物质突尼斯杂质含量硝酸盐浓度地下水污染微生物污染污水管网